Undergraduate Theses

A design of a low-pressure steam turbine

Sat, 01 Jan 1910 00:00:00 GMT

A design of a low-pressure steam turbine Jones, Bradley. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1910

Development of a high-speed light source suitable for photoelastic studies

Wed, 01 Jan 1941 00:00:00 GMT

Development of a high-speed light source suitable for photoelastic studies Wyle, Frank S. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1941; Includes bibliographical references (leaf 25).

Double valves

Mon, 01 Jan 1877 00:00:00 GMT

Double valves Faunce, Linus. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1877

The design of a hydraulic draft gear for railway passenger cars

Sun, 01 Jan 1922 00:00:00 GMT

The design of a hydraulic draft gear for railway passenger cars Pearson, Harry L.; McGrady, Charles T. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1922; Includes bibliographical references.

A study of "Chu-Ma" as a textile fiber

Tue, 01 Jan 1924 00:00:00 GMT

A study of "Chu-Ma" as a textile fiber Chou, Cheng Yu, 1901-; Hsueh, Tsu Kang. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1924

The transportation decision making process in metropolitan Boston

Sun, 01 Jan 1967 00:00:00 GMT

The transportation decision making process in metropolitan Boston Zinner, Richard Mark. Thesis: B.S., Massachusetts Institute of Technology, Department of Political Science, 1967; One unnumbered page inserted.; Bibliography: leaf 74.

Oscillographic presentation of impedances on the reflection-coefficient plane

Sat, 01 Jan 1949 00:00:00 GMT

Oscillographic presentation of impedances on the reflection-coefficient plane Eckhart, Myron.; Fowler, Earl Bealle. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1949

Laser induced photoionization of helium

Tue, 01 Jan 1980 00:00:00 GMT

Laser induced photoionization of helium Lewis, Wayne Lloyd. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1980; Includes bibliographical references.

Petrography and geology of the Shoshone mining region in northwestern Wyoming

Sun, 01 Jan 1922 00:00:00 GMT

Petrography and geology of the Shoshone mining region in northwestern Wyoming Benedict, P. C. (Platt Carrico), 1900-1969. Thesis: B.S., Massachusetts Institute of Technology, Department of Geology, 1922

The effect of settlements on the stresses in building frames

Tue, 01 Jan 1935 00:00:00 GMT

The effect of settlements on the stresses in building frames Granberg, Robert J. Thesis: B.S., Massachusetts Institute of Technology, Department of Building Engineering and Construction, 1935; Includes bibliographical references.

Irradiation grafting of styrene onto dacron fibers and films

Thu, 01 Jan 1959 00:00:00 GMT

Irradiation grafting of styrene onto dacron fibers and films Schnetzer, L. J.; Hendren, J. W. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1959; Includes bibliographical references (leaves 43-44).

An investigation of sound transmission irregularity in a one dimensional enclosure

Sat, 01 Jan 1949 00:00:00 GMT

An investigation of sound transmission irregularity in a one dimensional enclosure Foster, Isaac C. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1949

Analysis of a dynamic sales call policy model.

Mon, 01 Jan 1968 00:00:00 GMT

Analysis of a dynamic sales call policy model. Karash, Richard Ivan. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1968; Bibliography: leaf 97.

Comparative tests of the Boston Elevated Co's surface cars

Mon, 01 Jan 1912 00:00:00 GMT

Comparative tests of the Boston Elevated Co's surface cars Jones, Philip C.; Katsainos, Nicholas M. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1912

Dracut nickel ore ; Geology and concentration, ore no. 2592

Sun, 01 Jan 1905 00:00:00 GMT

Dracut nickel ore ; Geology and concentration, ore no. 2592 Burton, Eugene.; Spalding, William Livingston. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1905

A study of the field control operation of railway motors : a thesis

Thu, 01 Jan 1925 00:00:00 GMT

A study of the field control operation of railway motors : a thesis Davis, Stanley W. (Stanley Whitcomb) Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1925; Includes bibliographical references (leaf 91).

Compliance in a gyroscope gimbal

Wed, 01 Jan 1958 00:00:00 GMT

Compliance in a gyroscope gimbal Graham, James William. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1958

Planteez(tm) : business plan and preliminary research

Mon, 01 Jan 2001 00:00:00 GMT

Planteez(tm) : business plan and preliminary research Sanchez, Manuel A. (Manuel Andres), 1979- Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2001; Includes bibliographical references (p. 15).

Investigation of torquemeters for high speed shafts

Thu, 01 Jan 1959 00:00:00 GMT

Investigation of torquemeters for high speed shafts Saluja, Narinder S. (Narinder Singh) Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1959; Includes bibliographical references (leaves 64-67).

Rapid transit use of existing rail lines

Wed, 01 Jan 1958 00:00:00 GMT

Rapid transit use of existing rail lines Kenyon, Michael D. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1958; Includes bibliographical references (leaf 25).

Mass transfer from rotating cylinders

Sun, 01 Jan 1956 00:00:00 GMT

Mass transfer from rotating cylinders Cotter, John.; Schmidt, Guy L. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1956; Bibliography: leaf 38.

An observation about the Chicago Council and its policies

Thu, 01 Jan 1948 00:00:00 GMT

An observation about the Chicago Council and its policies Naber, Fred P. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1948

South End Center for the Arts.

Fri, 01 Jan 1965 00:00:00 GMT

South End Center for the Arts. Dunbar, Gary Arthur. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1965; "Special requirements for group A occupancy: theatres" leaves [34-42] inserted. "Special requirements for group C occupancy: schools" leaves [50-54] inserted.; Bibliography: leaf 20.

Micro-analysis of grinding machine cuttings

Sun, 01 Jan 1922 00:00:00 GMT

Micro-analysis of grinding machine cuttings Zurlo, J. V.; Terkelsen, E. A. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1922

Tests upon bamboo as a concrete reinforcement and a consideration of its application in construction

Tue, 01 Jan 1924 00:00:00 GMT

Tests upon bamboo as a concrete reinforcement and a consideration of its application in construction Young, Joe W.; Guo, Dianbang. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1924

The Image of the Tunnels: Mapping Perception of the MIT Underground

Thu, 01 May 2025 00:00:00 GMT

The Image of the Tunnels: Mapping Perception of the MIT Underground Ravichandran, Shruthi Kevin Lynch’s influential book, The Image of the City, proposes five elements by which residents of a space create mental maps of their neighborhood and use these to define their spatial perception and navigation: paths, edges, districts, nodes, and landmarks. The MIT Tunnels are spaces utilized daily for a myriad of purposes: to reach labs and offices, to avoid slow-moving tourist traffic and biting Boston cold, and to explore MIT’s iconic hacking spots. This work exploresif Lynchian principles apply to these pseudourban underground spaces and culminates in a GeoGuessr-inspired virtual game where students can test and grow their knowledge of tunnel navigation. The hypotheses tested in this thesis project extend Lynch’s framework to relevant tunnel analogs: familiar paths, districts (clusters of buildings and departments), tunnel landmarks, and cross-level relationships between above- and underground mental maps. These hypotheses were tested via preliminary surveys on MIT students. Once completed, the subsequent experiments involved two games - one physically in the tunnels, one online with images of the tunnels gathered with a 360-camera. The games involved having participants navigate to a target building from a starting point. After the in-person game was completed, participants answered a series of questions about their route. These races offered information about familiar paths, landmarks, and strategies participants used to navigate the tunnels. Results from this game confirmed conclusions drawn from preliminary surveys that Lynchian principles do extend to the tunnels via relevant analogs, and above-ground knowledge and connection points offered even more information than Lynch’s five principles alone. Students consistently rely on heavily traveled paths, navigating through familiar districts, and using above ground knowledge to traverse in unknown underground buildings. This work can be extended to help grow students’ understanding of these tunnels, fostering further creativity and student expression in this complex network of spaces.

Dishing It Out: Reimagining Multicultural College Dining Through Student-Centered Design

Thu, 01 May 2025 00:00:00 GMT

Dishing It Out: Reimagining Multicultural College Dining Through Student-Centered Design Dong, Annie Dining halls are central spaces in colleges, fostering not only nourishment but also cultural connection and community. However, when dining centers fall short in catering to the needs of their multicultural student body, students are often left feeling isolated and even further from home. Using MIT as a case study, this thesis employs user research and digital storytelling to explore how collecting student perspectives can inform college dining centers on better supporting the diverse cultural backgrounds and dietary needs of their students. The research and findings highlight the critical gaps and strengths in cultural representation within MIT’s dining halls. Through surveys and user research, this thesis gathers student perspectives on food authenticity, comfort, and identity, which inform the design of an interactive website prototype exploring student culinary backgrounds and preferences. This project serves as both a resource for dining services and a digital cookbook curated by the student body. By centering student voices through a culinary lens, this project aims to reimagine dining spaces as inclusive, representative, and comforting shared spaces within college campuses.

The simulation of a multi-product, multi-department factory

Wed, 01 Jan 1964 00:00:00 GMT

The simulation of a multi-product, multi-department factory Levy, Donald Stephen. Thesis: B.S., Massachusetts Institute of Technology, School of Industrial Management, 1964

Comparative elastic and plastic analysis and design of steel frames

Fri, 01 Jan 1960 00:00:00 GMT

Comparative elastic and plastic analysis and design of steel frames Padilla Valenzuela, Rodolfo Augusto. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil and Sanitary Engineering, 1960

A financial history of the Boston elevated

Fri, 01 Jan 1926 00:00:00 GMT

A financial history of the Boston elevated Stallman, Edward B.; Bush, Horace McM. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1926; Includes bibliographical references (leaf 34).

Verse and Reversal: The Poetic Return to the Inner Child as Black Revolutionary Praxis

Thu, 01 May 2025 00:00:00 GMT

Verse and Reversal: The Poetic Return to the Inner Child as Black Revolutionary Praxis Dunnell, Kaelyn Black revolutionary movements historically have centered the role of the Black child—as either foundation, visionary, or representation of Black liberation. The identity of any given revolutionary movement is characterized by three tenets: resistance, imagination, and love. In order for the individual to uncover the origin of these three tenets for themselves. This thesis is about the poiesis of the revolutionary—the making and re-making of the revolutionary—and in it I argue that the very process of forming revolutionary identity is poetic. I coin the phrase poetic revolutionary to capture that process, which involves tapping into the font of revolutionary soulfulness, which is one’s inner child or the voice and experience of the Black child. The literature guiding this analysis is from June Jordan’s archive hosted at Schlesinger Library, with Voice of the Children, a children’s publication edited by Jordan, as one of the most notable works. I examine June Jordan as the model of the Black revolutionary who has uncovered the language of her child, and I also examine the works of the children she worked with (whose 13– 15-year age ranges, notably, are on the cusp of the definition of childhood that I adopt in this thesis—more in Section I). I gather evidence from workshop diary entries written by Jordan and by her students, poetry excerpts from Voice of the Children, and Jordan’s own writing from her childhood and beyond to support my theory of the poetic revolutionary.

AI Through the Viewfinder: Reimagining the Camera as a Tool for AI Image Generation

Wed, 01 May 2024 00:00:00 GMT

AI Through the Viewfinder: Reimagining the Camera as a Tool for AI Image Generation Shodipo, Bukunmi The rapid emergence of artificial intelligence (AI) is causing profound shifts within the art world, reigniting age-old debates on the boundaries of what can be considered art. For example, many AI systems are employed to mimic the styles of existing artists and their works. Although this approach is deemed to be derivative and uninspiring to many people in the art world, it is also forcing us to reconsider longstanding beliefs attached to creativity such as the importance of originality and authorship. Given that AI is here to stay, this thesis explores a critical question around AI and perception, asking “How and what does AI see? Specifically, this thesis investigates the types of biases that are ingrained or embedded into AI systems, and how these biases are reflected in the output, specifically in the context of images. As part of this investigation, this thesis culminates with a prototype - an AI camera that embodies the process of AI ‘seeing the world’. This camera integrates photography with artificial intelligence, serving not only as a tool for technical exploration but also as a metaphor for examining how AI technologies offer diverse and potentially transformative perspectives on reality, much like a traditional camera. By abstracting AI technology into a camera, this project aims to start a conversation about how AI, like a camera, offers us different, sometimes biased views of the world. In doing so, the camera is redefined from a mere tool for capturing images to one that generates them, and in some cases (mis)represents human forms and identities.

An anthropological study based upon observations of complexion and cephalic measurements of students at the Massachusetts Institute of Technology

Wed, 01 Jan 1896 00:00:00 GMT

An anthropological study based upon observations of complexion and cephalic measurements of students at the Massachusetts Institute of Technology Fisk, Harry George.; Melluish, James George. Thesis: B.S., Massachusetts Institute of Technology, Department of General Studies, 1896

The design and construction of a new density photometer

Mon, 01 Jan 1923 00:00:00 GMT

The design and construction of a new density photometer Brown, Sherwood Fiske.; Perkins, Oliver L. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrochemical Engineering, 1923; Includes bibliographical references (leaves 17-18).

The Pleasant Valley, Nova Scotia, Limestone

Thu, 01 Jan 1959 00:00:00 GMT

The Pleasant Valley, Nova Scotia, Limestone Jeffries, James T.; Manlove, Robert F. Thesis: B.S., Massachusetts Institute of Technology, Department of Geology, 1959; Includes bibliographical references (leaf 63).

Design and evaluation of a frequency-shifting hearing aid.

Sun, 01 Jan 1978 00:00:00 GMT

Design and evaluation of a frequency-shifting hearing aid. Falkenburg, Douglas Emil. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1978; Bibliography: leaves 103-104.

Tool and chip temperatures in machine shop practice

Tue, 01 Jan 1924 00:00:00 GMT

Tool and chip temperatures in machine shop practice Shore, Henry. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1924; Includes bibliographical references.

The oxidation of sulphur dioxide in Cottrell precipitators of a contact sulphuric acid plant

Thu, 01 Jan 1931 00:00:00 GMT

The oxidation of sulphur dioxide in Cottrell precipitators of a contact sulphuric acid plant Haberstoh, Robert H.; Milligan, Sydney.; Roever, Paul H. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1931

Production of carbon black by the decomposition of methane with electrically heated wires

Sun, 01 Jan 1939 00:00:00 GMT

Production of carbon black by the decomposition of methane with electrically heated wires Donatello, Dominic G. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1939; Includes bibliographical references (leaf 24).

Design of a voltage-limiting device using SIC nonlinear resistors.

Tue, 01 Jan 1974 00:00:00 GMT

Design of a voltage-limiting device using SIC nonlinear resistors. Asamoah, William Kafui. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1974; Includes bibliographical references.

An analog circuit simulator for the Connection Machine

Thu, 01 Jan 1987 00:00:00 GMT

An analog circuit simulator for the Connection Machine De Beus, Eric. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1987; Includes bibliographical references.

A study of the developments in the construction, equipment and operation of street railway cars

Thu, 01 Jan 1920 00:00:00 GMT

A study of the developments in the construction, equipment and operation of street railway cars French, Grant Keith. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1920

Development of a 3D Printer for Oxide-free Aluminum Transportation

Thu, 01 May 2025 00:00:00 GMT

Development of a 3D Printer for Oxide-free Aluminum Transportation Smith, Henry R. Hydrogen as an energy carrier is abundant, has a high caloric value and only produces water when combusted. A challenge is directly transporting hydrogen incurs high costs due to its low density. The low flammability limit also makes it dangerous to transport. Aluminum has been proposed as an alternative energy carrier for its high density and ability to be stored at ambient conditions, allowing for cheaper transportation. Hydrogen can be produced on-site by reacting the aluminum fuel with water. However, when exposed to air aluminum forms an inert oxide layer on its surface, preventing reaction. High reaction temperatures are required to overcome the oxide layer leading to a high energy penalty. This thesis proposes a novel concept of aluminum encapsulation with water-soluble polymer. A 3d printer was designed and fabricated which creates aluminum-polymer structures that do not oxidize during storage and can achieve a wide range of reaction rates with water by varying the structure surface area. This new approach provides several benefits, by removing the oxide layer before the reaction happens, the aluminum is in an “activated” state and can react at room temperature. This reduces the energy required for reaction. Additionally, by having control over the reaction rate, ideal production rates can be achieved, reducing waste products and meeting consumption demands. The unique manufacturing flexibility of 3d printers enables the fabrication of structures with wide ranges of surface area to volume ratios. By shipping activated aluminum in the polymer structures, hydrogen can be produced locally and the need for expensive hydrogen transport can be eliminated.

Design and Development of an Atmospheric Dispersion Compensator for the LLAMAS instrument on the 6.5m Baade Magellan Telescope

Thu, 01 May 2025 00:00:00 GMT

Design and Development of an Atmospheric Dispersion Compensator for the LLAMAS instrument on the 6.5m Baade Magellan Telescope Berlanga Molina, Gerardo A. Atmospheric Dispersion is a phenomenon caused by the wavelength dependent refraction of incoming light by Earth’s atmosphere. For non-perpendicular angle of incidence, higher energy light (shorter wavelength) such as blue and violet are refracted more than its lower energy counterparts, for example, red light. As such, when a telescope is pointed at a non-zero zenith angle, there is a varying vertical angular separation between the different wavelengths of incoming light. In order to mitigate this separation and improve the spectral response of a scientific instrument, an Atmospheric Dispersion Compensator (ADC) is employed. At its simplest, this is a device consisting of two zero-deviation prisms that counter-rotate to counteract the unwanted atmospheric dispersion. At zenith, their dispersion axes cancel each other out, and near the horizon, their axes are parallel such that their net dispersion is opposite to that of the atmosphere. Here, a novel otpo-mechanical realization of an Atmospheric Dispersion Compensator is explored involving two hollow stepper motors with the appropriate diameters to house near-athermally RTV bonded powered optic lenses in order to meet dimensional constraints that prevented a more conventional ADC design. Using Hall-effect sensors, the ADC is able to reliably home without the need of motor encoders for positioning. Upon the ADC’s installation on the Large Lenslet Array MAgellan Spectrograph (LLAMAS) and the latter’s subsequent successful commissioning on the 6.5m Baade Magellan Telescope, the ADC has been operating and helping astronomers every night.

G-Code Based Toolpath Simulation for Predicting CNC Energy Consumption

Thu, 01 May 2025 00:00:00 GMT

G-Code Based Toolpath Simulation for Predicting CNC Energy Consumption Anziani, Jonathan Machining is an energy intensive process, and being able to model the energy consumption of machining would allow manufacturers to consider how to reduce their energy footprint. While many models have been developed for estimating energy consumption, they are not easily applicable or accessible to CNC machining, where the material removal rate is variable. This thesis develops a G-code based simulation that uses a voxel mesh to virtually recreate material removal, approximating the material removal rate at discretized points in the machining process. Using an energy consumption model and machine power data, material removal rates are related to the power consumption of machining the part. The simulation pipeline was validated using power data collected from literature, and for a constant material removal rate the model has shown average absolute error of 3.17% predicting power and 2.89% predicting specific energy consumption for simulated test geometries.

Active Multi-View Object Pose Estimation Using a Mobile Ground Robot

Thu, 01 May 2025 00:00:00 GMT

Active Multi-View Object Pose Estimation Using a Mobile Ground Robot Wynia, Ethan Accurate 6-DoF object pose estimation remains a central challenge in robotic perception, particularly when relying on single-view observations subject to occlusions and limited geometric cues. This thesis presents a system that incrementally refines object pose estimates by collecting multi-view observations with a mobile ground robot, the Clearpath Jackal. The robot autonomously navigates in a circular trajectory around a target object, capturing images while maintaining a fixed orientation toward the object center. At each waypoint, 2D image corners are manually annotated and paired with corresponding 3D object coordinates. The Perspective-n-Point (solvePnP) algorithm is then applied to estimate the object's pose relative to the camera. The system transforms these camera-centric poses into a consistent global frame using Robot Operating Systems’ transform library. Using these poses, the system tracks reprojection error to evaluate pose confidence. Across multiple trials, the mean reprojection error consistently decreased as more views were added, confirming that spatially diverse observations improve pose estimation accuracy. A cross-run analysis shows reproducible trends, with error reductions of over 40% in many cases. These results validate the efficacy of active multi-view collection for reducing uncertainty and lay the foundation for future extensions with automated key point detection and You Only Look Once (YOLO) supported multi object detection.

Design of an FSAE Cooling System for Electric In-hub Motors

Thu, 01 May 2025 00:00:00 GMT

Design of an FSAE Cooling System for Electric In-hub Motors Lohawala, Sehar This thesis explores the design of water cooled electric in-hub motors for use in high power automotive applications such as Formula SAE Electric student racecars. The main components of the drivetrain of the 4WD electric vehicle are the motor and the motor controller. This thesis focuses on designing a reliable cooling system for the motors to ensure that they operate in an optimal temperature range that increases drivetrain efficiency, prevents catastrophic motor damage, and ultimately improves vehicle performance. During the design process, extensive heat transfer analysis was conducted for liquid cooling, air cooling, and heat pipes. Additionally, CFD was conducted for various water cooling architectures to determine the influence of coolant flow direction and channel dimensions on cooling performance. Results were subsequently analyzed, plotted, and used in the motor cooling architecture selection process. After determining the motor cooling sleeve architecture and dimensions, detailed CAD was created for both plastic prototype sleeves as well as metal 3D printed sleeves. Testing demonstrated that the cooling sleeve successfully met its target pressure drop of 3-4PSI. More thorough testing and data collection of the cooling sleeve’s thermal performance is still in progress. While details on the CAD, prototyping, testing & validation, and manufacturing, are outside the scope of this thesis, images are included for reference.

Open-IRIS: Low Cost, Fully Open Source In-situ Infrared Inspection of Silicon

Thu, 01 May 2025 00:00:00 GMT

Open-IRIS: Low Cost, Fully Open Source In-situ Infrared Inspection of Silicon Becker, Aaron M. Short-Wave Infrared (SWIR) imaging has become a powerful and well-known technique over the last two decades for silicon inspection and imaging. Open-IRIS is a low-cost, fully open-source system for in-situ InfraRed Inspection of Silicon devices (IRIS). It is designed to lower the cost barrier for academic and research users requiring high-precision IR imaging of silicon microelectronics. This thesis details the design and implementation of the Open-IRIS platform, including its optomechanical components, motion control system, electrical system and software architecture. Its design is highly modular and low cost, making it an invaluable and extensible tool for many future applications, including microarchitectural security research, chip failure analysis, and biological imaging. Key design challenges, such as achieving high mechanical and optical resolution on a budget are addressed. Computational microscopy techniques, including Fourier Ptychographic Microscopy (FPM), are evaluated to improve resolution. The system’s imaging resolution on a standard resolution target is evaluated, as well as its motion repeatability and accuracy. Results show that Open-IRIS achieves 5.34 μm optical resolution with a 5x objective, and 3.47 μm resolution with a 20x objective. Mechanically, it has 6.5 μm repeatability, and 35.5 μm accuracy, all on a total budget of less then US$1000 - a fraction of the cost of comparable commercial systems. The complete design is fully open-source, enabling broader access to advanced chip inspection techniques, and serves as an excellent starting point for future expansion into advanced security research like laser fault injection.

Electrifying a Jet Ski: Designing & Manufacturing an Electric Drivetrain for a Personal Watercraft

Thu, 01 May 2025 00:00:00 GMT

Electrifying a Jet Ski: Designing & Manufacturing an Electric Drivetrain for a Personal Watercraft Hudspeth, Blake H. While many vehicles are well into their transition to electrification, marine vessels are lagging behind; specifically, there are very few electric personal watercrafts (PWC) on the market. Though many engineers and hobbyists have retrofitted combustion engines for cars, motorcycles, and other automobiles for electric propulsion, there are almost no examples of electric conversions for watercraft. This thesis details the designing and manufacturing process of an electric drive train into a 1997 Yamaha Wave Venture 760 Personal Watercraft (PWC). This project aims to serve as a proof of concept for interchanging a combustion engine from an older PWC with an electric motor and Lithium-Ion battery. I performed rigorous calculations to properly size a battery and motor to propel the watercraft. Upon learning to weld, build battery packs, and configure a battery management system, I prototyped extensively—iterating upon battery packs and pack configurations. I assembled a final 72V, 10.4 AH battery pack with waterproof housing to power the 5kW motor that I coupled to the existing impeller drive shaft. Lastly, I performed a dry test monitoring the battery and motor health, confirming successful retrofit of the electric drive train, proving the feasibility in electrifying a used personal watercraft.

The effects of different stiffnesses and coefficient of drag on the performance of a Padel racket

Thu, 01 May 2025 00:00:00 GMT

The effects of different stiffnesses and coefficient of drag on the performance of a Padel racket Mora Armendariz, Francisco David The sport of padel is the fastest growing sport in the world. As the sport has evolved there have been more and more innovations in the equipment of Padel. One of the most important was moving from wooden paddles to ones made of fiber glass and carbon fiber. As such a prototype racket was designed and manufactured for this study through experiments to obtain data on existing commercially available rackets, a specific design was proposed and created. The prototype created is then compared to the other rackets in the same way that the original properties were measured. Although this racket needs to continue to be iterated on, the potential of a viable competitive racket is promising.

Tension Activated Kirigami Structures for Interlayer Use in Circular Construction Applications

Thu, 01 May 2025 00:00:00 GMT

Tension Activated Kirigami Structures for Interlayer Use in Circular Construction Applications Bigler, Thomas Motivated by the use of fully circular materials and improving sustainability, this thesis investigates the use of tension-activated kirigami as an architected material, for which mechanical properties are determined by their designed structure (geometry) rather than the bulk material itself. These architected materials can be used as a dry replacement for adhesives in construction with glass masonry units, enabling reclaimability and recyclability of both the interlayer material and glass masonry unit. The kirigami design and material selection allow for the customization of architected-material properties for best compatibility with the glass units. The research has involved both analytical/mathematical modeling for early material and design selection and an experimental process to develop an empirical database. Experimentation on different materials, designs, aspect ratios, etc. has provided data to begin extrapolating trends and behaviors of the architected material. These data will allow for design decisions and material selections based on the functional requirements of a specific structure or application.

The Design and Fabrication of a Punch and Die System for 2.008 Thermoformed Parts

Thu, 01 May 2025 00:00:00 GMT

The Design and Fabrication of a Punch and Die System for 2.008 Thermoformed Parts De Jesus, Sebastian As a student in 2.008, Manufacturing and Design II, our team successfully manufactured 100 identical yo-yos. Although the class is very well structured and the CNC milling, injection molding, and thermoforming in the Laboratory for Manufacturing and Productivity (LMP) were all optimized for the class, the punch and die system was one process that was more tedious than the rest. Punches, a die, and a calibration piece were designed, fabricated, and tested to find the best clearance size and fill in the gap in documentation of punching plastics. A new, working system was successfully fabricated and assembled, and clearance size 5% was determined to have a lower margin of alignment error. The new punch system will be implemented in the LMP and used by 2.008 students.

High Strain-Rate Responses of Mechanical Metamaterials

Thu, 01 May 2025 00:00:00 GMT

High Strain-Rate Responses of Mechanical Metamaterials DesRoberts, Collin G. Mechanical metamaterials—materials with deterministic microstructures that attain unique combinations of properties—have revolutionized the parameter space of engineering materials over the last decade. While their quasi-static mechanical responses have been thoroughly characterized, their responses in the dynamic regime are not fully understood, especially at strain rates above 10^3 s^−1. Using microscale uniaxial compression and custom microscale Kolsky bar capabilities, we uncover the strain rate dependence of mechanical metamaterials over eight orders of magnitude, ranging from strain rates of 10^−3 to 10^5 s^−1. Herein, we describe the development and execution of direct impact experiments using a custom-built micro Kolsky bar set-up, delving into the details of its design, fabrication, and data analysis. We first characterize the rate dependence of the polymer used for sample fabrication, IP-S, and relate it to the responses of different metamaterial morphologies at the same strain rates. The results of these experiments uncover how geometry greatly affects rate dependence of mechanical properties in the dynamic regime. Understanding the high strain rate behavior of metamaterials is necessary to ensure reliable performance in real-world applications.

Feedback Controller Design For Low-Power Autonomous Blimp Robot

Thu, 01 May 2025 00:00:00 GMT

Feedback Controller Design For Low-Power Autonomous Blimp Robot Ilerbaig-Bajona, Pau J. Low-power autonomous robots are able to do things that humans cannot do alone, ranging from small robots that traverse through the human body or other tight spaces to surveillance and monitoring robots that perform extended missions. Navigation is a key power draw for these robots, and thus, their motion planning must be designed to minimize power usage. In order to test motion planning algorithms, a low-power autonomous blimp robot that uses buoyancy to reduce power requirements for three-dimensional movement was designed. The blimp has two forward-facing rotors and two vertically-facing rotors. Due to the underactuated nature of the robot, the blimp cannot be translated sideways, thus leading to a coupling of the blimp’s two horizontal degrees of freedom. To control this, we present a controller for the blimp robot with three separate PID control loops: one for altitude control, one for angle control, and one for proximity approach. Additional fuzzy logic is implemented to improve performance and limit inefficiencies in the dynamic system and controller, such as turning towards the goal first before approaching forward. Combining the PID control loops and fuzzy logic allows for movement from a start point to a goal point, remaining within a 0.3 m radius of the goal point once it is reached. Further work that can be done to improve the physical system and controller is discussed, such as balancing the blimp gondola and rotors, as well as implementing different, physics-based controllers.

Testing Soccer Cleats Designed to Reduce ACL Tears

Thu, 01 May 2025 00:00:00 GMT

Testing Soccer Cleats Designed to Reduce ACL Tears Sandell, Remi One of the most common lower extremity injuries in soccer are ACL tears which have a long recovery time of 6-13 months and have a high risk of reinjury. The majority of ACL tears are non-contact and the mechanism behind them has been explained to be related to landing flatfooted. This provides an opportunity for engineers to design cleats to reduce the risk of these injuries. The company HBN shoes designed a soccer cleat aimed at reducing ACL tears by increasing the flexibility of the cleat around the metatarsophalangeal joint. The idea behind this is that increased flexibility at this joint will decrease landing flat-footed while running, reducing injury risk. This study evaluated the ability of the shoe to decrease flat-foot running and flatfooted landing while passing the ball using Fscan pressure sensors and GoPro cameras. For the majority of the participants in the study, the HBN cleats had a reduced peak heel force during running compared to the test cleats. When passing the ball wearing the HBN cleats, the majority of participants had a lower percentage of the planting step in a flat-footed position compared to the control cleats. This indicates that the HBN cleats could be effective in reducing flat-footed running and landing in athletes.

Race Car Reverse Gear Design

Thu, 01 May 2025 00:00:00 GMT

Race Car Reverse Gear Design English, Ashley E. This thesis presents the design, simulation, and installation of a reverse gear system for the RUSH SR, a lightweight, motorcycle-engine-powered race car that lacks built-in reverse capability. The proposed solution repurposes a high-torque automotive starter motor to drive the car in reverse through engagement with a custom ring gear on the rear differential. Analytical modeling and time-domain simulation were used to evaluate performance under varying loads, including the effect of incline angle on terminal velocity and motor current draw. Simulated results show that the system can reliably move the car in reverse on slopes up to 10° before stalling, with current draw remaining within safe operational limits. The mechanical design includes a new differential carrier, gear coupler, and ring gear, while the electrical system explores both off-the-shelf and custom high-side switching controllers to manage power and solenoid activation. The final hardware was bench tested and installed on a working vehicle. Recommendations for future validation include current-limited incline testing and dynamic vehicle response trials. This modular and cost-effective system demonstrates a practical solution to a common race car limitation while preserving the RUSH SR’s lightweight performance characteristics.

Design and Characterization of a Pressure Controller Test Stand for Soft Pneumatic Actuator Testing

Thu, 01 May 2025 00:00:00 GMT

Design and Characterization of a Pressure Controller Test Stand for Soft Pneumatic Actuator Testing Comiskey, Evan L. Soft pneumatic actuator design has been of interest to the soft robotics community in recent years for their potential to expand the roles of robotics systems in human-interacting medical devices and delicate manufacturing processes. Unfortunately, it is difficult to analytically predict the degradation behavior over time of soft pneumatic actuators, and to compare such behavior in a repeatable manner between different actuator designs. To gather such degradation data experimentally, this thesis presents an open-source proportional-integralcontrol (PID) control test stand system with only off-the-shelf components, in order to create a tool for standardized and repeatable characterization testing of soft pneumatic actuator life-cycle behavior. The system is open-source and modular, allowing researchers in the MIT Fabrication-Integrated Design Lab (FIDL) as well as other soft robotics researchers to customize the program and associated hardware as necessary for their own soft pneumatic actuator research inquiries. This thesis explores the design of both the hardware and software of this test stand system, which is informed by the system’s functional requirements, and additionally explores the PID controller’s capabilities and limitations.

Exploring Visual and Haptic Feedback Systems on User Performance with a Hand-Held Robot

Thu, 01 May 2025 00:00:00 GMT

Exploring Visual and Haptic Feedback Systems on User Performance with a Hand-Held Robot Shiferaw, Ruth While robotic systems allow users to maintain accuracy in high-precision environments, achieving intuitive control is challenging without real-time feedback. Haptic feedback, which communicates otherwise unfelt sensations through vibrations, is widely used in consumer technologies such as video games and smartphones. However, in contexts where knowing the precise force applied by the robot is critical—such as medical procedures or hazardous environments—haptic cues alone may provide insufficient resolution, increasing user workload. Visual feedback, by contrast, is more commonly used and offers greater versatility and precision. This study compared the impact of visual feedback (a color-changing LED light strip) and haptic feedback (vibrations in a controller) on user performance in a “fragile object” manipulation task. Nine participants completed the task under four feedback conditions: no feedback, visual feedback, haptic feedback, and combined visual-haptic feedback. Subjective ratings showed that most participants preferred modalities that included visual cues, citing lower perceived workload and clearer force awareness. However, despite some participants reporting minimal benefit from haptics, performance metrics revealed that for others, haptic feedback meaningfully supported task success. These findings suggest that while simple visual indicators, such as green-yellow-orange-red light strips, provide accessible and interpretable force feedback, the integration of haptic cues can enhance performance by offering complementary real-time force information. Future designs may benefit from refining both modalities to balance intuitiveness, resolution, and user comfort, especially in applications requiring precise force modulation.

Simulation-Based Reinforcement Learning Policy Optimization for Tactile Manipulation: A Case Study on the Eyesight Hand

Thu, 01 May 2025 00:00:00 GMT

Simulation-Based Reinforcement Learning Policy Optimization for Tactile Manipulation: A Case Study on the Eyesight Hand Chang, Ethan Robotic manipulation remains a complex and unsolved challenge due to the need for adaptability across diverse objects and tasks. In this work, we explore how to train effective manipulation policies using reinforcement learning in simulation for the Eyesight Hand: a novel, low-cost, tactile-enabled robotic hand. We implement a range of experiments in MuJoCo to evaluate the impact of controller types, observation spaces, reward formulations, and curriculum strategies on policy performance. Our findings highlight the benefits of delta position control, a carefully selected observation space including joint states, control vectors, object pose, and contact forces, and success-driven curriculum learning. Our study establishes baseline strategies for training robust, tactile-based policies on this in-house hardware.

Designer-User Validation of a Method for Predicting Cognitive Interventions for Sustainable Product Design

Thu, 01 May 2025 00:00:00 GMT

Designer-User Validation of a Method for Predicting Cognitive Interventions for Sustainable Product Design Ladolcetta, Mia Life cycle assessments to measure the environmental impact of products is often limited by a lack of information about the use phase of a product. To aid this gap by encouraging sustainable user behavior from the early brainstorming and prototype phases of product development, principles of environmental psychology and sustainable product design can be linked through determinants of pro-environmental behavior and cognitive interventions included as product features. A study will be completed to validate these relationships by surveying participants on their determinants, grouping participants into personas that share similar determinant ratings, then pitching sketch prototypes developed with corresponding cognitive interventions and measuring their receptiveness to each sketch prototype. To aid in the development of this sketch prototype evaluation survey, a series of user interviews were conducted with the sample use case of factors that encourage the use of reusable water bottles to better understand how users may evaluate the products depicted in the sketch prototypes. Validating the links between determinants and cognitive interventions can assist designers in determining a hierarchy in the determinants they design for and more efficiently select effective cognitive interventions for users with different experiences.

Effect of Recycling Stream Contaminants on Extrusion and Mechanical Properties of rPET

Thu, 01 May 2025 00:00:00 GMT

Effect of Recycling Stream Contaminants on Extrusion and Mechanical Properties of rPET Escandon, Mercedes The emerging field of large-scale additive manufacturing has a wide range of applications including the potential to use recycled plastics. A type of 3D printing that can use recycled plastics is Fused Granulate Fabrication, which takes in polymer pellets and melts them down in a screw and barrel before extruding them layer by layer. The process of turning plastic trash into print-ready pellets typically involves sorting, shredding, washing, drying, and re-extruding the material into pellets, each step requiring time, equipment, and energy. To reduce both the cost and carbon footprint of 3D printing with recycled plastic, some of these steps could potentially be eliminated. Washing and drying plastic is a very energy-intensive step that could potentially be skipped or significantly modified. The possibility of using unwashed plastics in 3D printing was explored, focusing on residual beverage contamination. Controlled amounts of soda were introduced to clean, virgin PET pellets prior to drying. The contamination levels ranged from 0.25% to 3% soda by mass. The plastic was melted and extruded into thin strands using a stationary horizontal extruder and a conveyor belt. The mass flow rate was determined from the mass of strands to quantify the quality of extrusion. No significant effect of contamination level on mass flow rate was measured. The strength of the parts was determined using a tensile test. The Young’s Modulus initially increases with the contamination level, peaking at 1% contamination with a Young’s Modulus of 2.80 GPa, which was 30% higher than the measured value for the clean PET. Above 1% contamination, there was a significant drop off strength. These results demonstrate that there is an acceptable level of beverage contamination when recycling plastic.

Measuring Density of Novel Technorganic Material

Thu, 01 May 2025 00:00:00 GMT

Measuring Density of Novel Technorganic Material Ramos-Munoz, Jorge Felix Self-healing technorganic materials are critical for organ printing/repair operations. This study characterized one such technorganic material by measuring its density. By ascertaining the density of the material, we hope to later derive other important properties including: the speed of sound within the material, its stiffness, its conductivity, and its natural frequency. The material in question was printed on a gold substrate by depositing hexane within a silver nitrate solution. The density was obtained by observing the volume change of the solution in which it was printed and by measuring the sample’s mass. A final density of 0.622±pm 0.227 g/cm³ was measured, and we hope to continue characterizing the material’s mechanical, thermal, and electrical properties with future studies.

Design and Testing of a Hadal Sediment Sampling System

Thu, 01 May 2025 00:00:00 GMT

Design and Testing of a Hadal Sediment Sampling System Do, Thao X. Sediment cores are conventionally gathered to collect data on seabed chemical and mineral composition. These samples are important in determining the health of the surrounding environment and, if sediment layers are preserved, assessing the environmental history and trajectory of our ocean floors. Over the last few decades, some attempts to collect sediment core samples have been made from as deep as the Mariana Trench, which contains the deepest known point on Earth’s surface at 11,000 meters [1] [2]. However, the hadal region remains one of the most underexplored areas of our oceans [3]. Working in conjunction with Inkfish, a submersible technology company, we developed a deep-sea sediment core sampler that will travel to the Mariana Trench aboard one of Inkfish’s submersible landers and will collect four inches of sediment in ambient pressures of 110.32 MPa [4]. The first phase of this project was to design and fabricate a prototype sediment core sampling device. We designed an entirely mechanical sampler because underwater actuators suitable for use in hadal conditions are difficult to source and require additional communication and power resources. Furthermore, our device aims to preserve the layers of the sediment core samples as the lander ascends to preserve relative time scales within the sample. The next phase involved testing the functionality of different subsystems of our device. In this paper, we considered two different sediment collection apparatuses and one-way valves for our collection tube. We performed field testing at the Charles River in Cambridge, MA to assess which apparatus and valve combination would provide the best results based on the volume of sediment collected and retained. Building on our mechanical proof-of-concept, we improved the design and fabricated a second iteration prototype for 2-3 km depths. In this version, we addressed the two main weaknesses of the initial proof of concept design: substantial friction during sliding and the complexity of assembly and maintenance due to the numerous parts. Lastly, we engineered a deployment system that made our device compatible with Inkfish’s lander deployment procedure. The deployment system was designed to lower the sediment sampler device from within the bay to below the lander once the lander was submerged in water. In early October, the improved sediment sampler and the deployment system were tested during an engineering expedition near the shores of Tonga. Ultimately, we believe that our sediment sampler presents a viable purely mechanical solution to collecting deep-sea sediment from profoundly unexplored areas at hadal depths like the Mariana Trench. Our sampler can easily be mounted onto any surface where it would touch the ocean floor, requiring no electronics or controls. Though we were constrained by the particular seafloor lander used by Inkfish, the size of the sampler is scalable, allowing both the sample diameter and depth to be adjusted for a given mission. By making these sediment samples more accessible, we believe we will have an impact across a number of marine research areas.

Engineering Principles for Scalable Connectomics

Thu, 01 May 2025 00:00:00 GMT

Engineering Principles for Scalable Connectomics Garzon Navarro, Monserrate Brain tissue sectioning presents a significant challenge in connectomics, particularly when scaling to larger volumes. In the MICrONS 1 mm³ mouse visual cortex dataset, 25.1% of scanned images—representing over a month of imaging work—were discarded due to sectioning defects. Current methods result in material loss during cutting and face limitations in tool wear and process efficiency. This thesis examines tissue sectioning through an engineering lens. Drawing from established machining practices and parallel industries, we propose and evaluate potential improvements to sectioning methods. The work aims to contribute to ongoing efforts in mapping larger connectomes, making it more practical and less error-prone.

Ideology and the First Gothics

Mon, 01 Jan 1990 00:00:00 GMT

Ideology and the First Gothics Grove, Allen Whitlock Thesis: B.S., Massachusetts Institute of Technology, Literature

The melting points of isopropyl esters of aromatic nitro acids

Mon, 01 Jan 1923 00:00:00 GMT

The melting points of isopropyl esters of aromatic nitro acids Zeng, Zhaolun, 1898-1967. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1923

An investigation of certain concrete sands in the vicinity of Portland, Maine

Sat, 01 Jan 1927 00:00:00 GMT

An investigation of certain concrete sands in the vicinity of Portland, Maine Blandford, Sidney E. (Sidney Edgar); Cheney, Laurence B. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1927

The misfit and the non-specialist student at M.I.T.

Sun, 01 Jan 1939 00:00:00 GMT

The misfit and the non-specialist student at M.I.T. Peskoe, Irving. Thesis: B.S., Massachusetts Institute of Technology, Department of General Science, 1939; Includes bibliographical references (leaf 64).

The buckling load of hyperbolic paraboloid shells

Mon, 01 Jan 1962 00:00:00 GMT

The buckling load of hyperbolic paraboloid shells Lee, Samuel Tak. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil and Sanitary Engineering, 1962; Includes bibliographical references (leaf 85).

A study of maladjustment in the class of 1955 at M. I. T.

Sat, 01 Jan 1955 00:00:00 GMT

A study of maladjustment in the class of 1955 at M. I. T. Langberg, Arnold. Thesis: B.S., Massachusetts Institute of Technology, Department of General Engineering, 1955

Education in the humanities at the Massachusetts Institute of Technology.

Sat, 01 Jan 1966 00:00:00 GMT

Education in the humanities at the Massachusetts Institute of Technology. Perrolle, Judith Ann. Thesis: B.S., Massachusetts Institute of Technology, Department of Humanities, 1966; Bibliography: leaves 98-99.

Going to MIT.

Fri, 01 Jan 1965 00:00:00 GMT

Going to MIT. Landau, David Lewis. Thesis: B.S., Massachusetts Institute of Technology, Department of Humanities, 1965

The 1970 student strike: the children's crusade at MIT; a study in contemporary history.

Mon, 01 Jan 1973 00:00:00 GMT

The 1970 student strike: the children's crusade at MIT; a study in contemporary history. Giguere, Lee David. Thesis: B.S., Massachusetts Institute of Technology, Department of Humanities, 1973; Leaf 69 used twice.; Bibliography: leaf 163.

The style of M.I.T. education.

Thu, 01 Jan 1970 00:00:00 GMT

The style of M.I.T. education. Green, Patrick Conal. Thesis: B.S., Massachusetts Institute of Technology, Department of Humanities, 1970; Bibliography: leaf 55.

An examination of low hysteresis polyurethane for use in traction drive rolling elements

Thu, 01 Jan 1981 00:00:00 GMT

An examination of low hysteresis polyurethane for use in traction drive rolling elements Castellano, John Philip. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1981; Includes bibliographical references.

Career goals, attitudes, and interpersonal relationships of M.I.T. undergraduates

Fri, 01 Jan 1982 00:00:00 GMT

Career goals, attitudes, and interpersonal relationships of M.I.T. undergraduates Slaughter, Sarah. Thesis: B.S., Massachusetts Institute of Technology, Department of Humanities, 1982; Bibliography: leaf 99.

The work and meanings of science and engineering : interviews with MIT scholars

Fri, 01 Jan 1982 00:00:00 GMT

The work and meanings of science and engineering : interviews with MIT scholars Karaku, Alex Theodore. Thesis: B.S., Massachusetts Institute of Technology, Department of Humanities, 1982; Bibliography: leaf 14.

Nonpolarized relay

Fri, 01 Jan 1915 00:00:00 GMT

Nonpolarized relay Tseng, C. C. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1915

Contract design of a fleet replenishment ship

Sat, 01 Jan 1955 00:00:00 GMT

Contract design of a fleet replenishment ship Morcillo Dosman, Alfonso M. Thesis: B.S., Massachusetts Institute of Technology, Department of Naval Architecture and Marine Engineering, 1955; Bibliography: leaf 97.

Jurassic park--the thesis : simulation of dinosaur social behavior using behavior networks

Fri, 01 Jan 1993 00:00:00 GMT

Jurassic park--the thesis : simulation of dinosaur social behavior using behavior networks LeCompte, David W. (David William) Thesis: B.S., Massachusetts Institute of Technology, Department of Mathematics, 1993; Includes bibliographical references (leaves 38-39).

Students who change majors: a study of adolescent development at MIT.

Mon, 01 Jan 1968 00:00:00 GMT

Students who change majors: a study of adolescent development at MIT. Spitzer, Charles Mark. Thesis: B.S., Massachusetts Institute of Technology, Department of Humanities, 1968; Bibliography: leaves 77-78.

Modeling Exomoon Formation in Circumplanetary Disks Using Dustpy

Thu, 01 May 2025 00:00:00 GMT

Modeling Exomoon Formation in Circumplanetary Disks Using Dustpy Noto, Maurielle I. This study presents one-dimensional simulations of a viscously evolving, gas-starved circumplanetary disk (CPD) modeled around a Jupiter-like planet. The simulations investigate the conditions under which satellites may form, with a particular focus on identifying physical mechanisms that create pressure bumps and dust traps capable of triggering the streaming instability. Multiple simulations were conducted with injected dust particles having maximum sizes of 100 µm, 1 mm, and 1 cm, and with fragmentation velocities set to 100, 500, and 1000 cm/s. Results show that regardless of the initial maximum injection particle size, the CPD consistently evolves toward the same maximum grain size, 0.5 cm, driven by system-wide physical processes such as radial drift, gas-dust coupling, and fragmentation limits. Larger fragmentation velocities enable more rapid and extended particle growth, leading to earlier quasi-steady-state evolution and allowing grains to reach sizes beyond the fragmentation barrier in certain regions. An analysis of dust and gas radial velocity profiles was performed to examine the size-dependent dynamics of particles, offering insight into the evolving coupling between dust and gas across the disk. Although the simulations did not include dust back-reaction—thereby excluding the possibility of observing streaming instability—the framework establishes a baseline for future studies. Enabling back-reaction and incorporating substructures such as radial gaps would help identify localized regions of moon formation. These simulations also pave the way for further investigation into the roles of icelines and volatile transport in setting satellite composition and structure, contributing to a broader understanding of exomoon formation and habitability.

Single-Phase Heat Transfer Effects of Mixing Vane Geometries in a Narrow Rectangular Channel

Thu, 01 May 2025 00:00:00 GMT

Single-Phase Heat Transfer Effects of Mixing Vane Geometries in a Narrow Rectangular Channel Pisinger, Mateo Mixing vane geometries enhance the fuel-to-coolant heat transfer within nuclear reactors, which allows for more efficient use of power reactors. At the same time, their presence affects the critical heat flux (CHF), the upper limit to power produced by the reactor, within the reactor. Numerical simulations do not accurately reflect the changes to CHF when mixing vanes are included in nuclear fuel assemblies, suggesting that the CHF models are not resolving the boiling phenomena that occurs with mixing vane geometries. This thesis aims to address this gap by designing an experiment capable of directly resolving the local single- and two-phase heat transfer processes which occur when mixing vane geometries are introduced into flow channels, building on previously developed high spatial- and temporal- resolution optical and infrared imaging techniques. A high-resolution experimental database would allow researchers to understand the boiling physics at the smallest scales, enabling the creation of more advanced numerical tools for the design and safety analysis of nuclear power reactors. Single-phase heat transfer simulations using the commercial computational fluid dynamics code STAR-CCM+ were performed to aid in the design process, and a preliminary analysis of the results was conducted to identify key single-phase heat transfer phenomena. Modifications to an existing experiment were made for the inclusion of flow obstacles analogous to mixing vane geometries into a flow boiling experiment. Obstacle geometries were 3D printed using high-temperature resistant resin, allowing the creation of complex three-dimensional geometries within the experiment. Experimental validation of the simulations is needed, however, the preliminary analysis identified single-phase heat transfer phenomena of interest for further investigation. These include: the relationship between fluid velocity and turbulent kinetic energy with heat transfer; the effects of impinging flows on heat transfer; and the heat transport within and changing geometries.

Pygmalion and Adonis

Thu, 01 May 2025 00:00:00 GMT

Pygmalion and Adonis Wang, Madison This work contains parts of a draft for a novel with the working title of Pygmalion and Adonis. It can be split into three sections. The first section is the beginning of the novel where the main character Edvard is introduced. He is rejected from the Academy of Horizons, visits the Arbiter’s temple, and receives an unusual commission. The second section is a little after the first where Edvard finishes the statue and it comes to life. The now alive statue is named Marcy. In the third and last section, Edvard and Marcy visit a bookshop where they discover a unique device.

Daikon Summer

Thu, 01 May 2025 00:00:00 GMT

Daikon Summer Le, Alice Trang In Vietnamese, there’s a phrase “ôm sầu riêng” which means “holding onto your sadness on your own.” But if you read it literally, it means “holding durian.” When Juliette, a heartbroken college student, visits locations from her favorite film hoping to find a movie-magical romance, she unknowingly crosses paths with Hana, the film’s jaded screenwriter, who is struggling to come up with ideas for a new script after the end of a long-term relationship. After splitting from their partners, Juliette and Hana emotionally isolate themselves from others to erase the reminder of the connections they’ve lost. Juliette brings a daikon radish (no durians were for sale) around with her for company—rolling it around in a little red wagon—hoping to meet-cute with strangers at each movie location she visits. Meanwhile, Hana trades her normal routine for destructive habits to cope with the new absence surrounding her. However, unbeknownst to Juliette and Hana, while pursuing their own solitudes, they are together in their loneliness. As time passes, marked by missed connections and the daikon radishes that Juliette must replace, and by the new situations Hana gets herself into while searching for inspiration for her next film, the pair find they may have stumbled onto an unexpected path to getting closure that brings them towards one another. Part romance, part drama, part comedy, Daikon Summer is a coming of age story about learning how to be alone. It’s a film that sits with the unfinished, unresolved, and incomplete. The setting of the film—the fictional city of Berlin, California—feels at the same time as stagnant and painfully mundane as the characters’ internal worlds and as absurdly rose-colored as their dreams. In a summer heavy with a suffocating atmosphere of longing and existential ennui, the characters, at first too scared to be alone they can’t even let go of their sadness, learn to hold onto something else—the security of their own company and their growing conviction that they’ll run into something or someone exciting around the next corner. A story about finding one’s hope and romanticism again, Daikon Summer is both a love letter to cinema, to the tender ways stories can connect us to one another, and a meditation on the self in love.

Bridging Simple Models and Observations of the Flexure Zone around Antarctica

Thu, 01 May 2025 00:00:00 GMT

Bridging Simple Models and Observations of the Flexure Zone around Antarctica Cao, Rina This study evaluates whether the length of ice flexure zones in Antarctica can be used to infer the thickness of the ice and the effective Young’s modulus using a 1-D linear elastic beam bending model. The ice flexure zone is defined as the transition region between the grounded ice sheet and the free floating ice shelves, where the ice flexes due to the rise and fall of ocean tides. Surface elevation data from ICESat-2 were analyzed at several sites on the Ross Ice Shelf, and flexure bounds were identified using a derivative-based detection algorithm. The logarithmic relationship between the flexure length and the ice thickness consistently deviated from the predicted 4/3 slope, and the calculated values of Young’s modulus ranged widely, often exceeding the physically plausible limits. Furthermore, the flexure limits identified by the algorithm showed inconsistencies with the idealized beam-bending model. These results indicate that the assumptions of linear elasticity, constant thickness, and simple geometry are likely violated in real flexure zones. More sophisticated modeling approaches are needed to accurately capture the mechanics of ice shelf flexure zones.

Assessing Quantum Magnetometry as an EmergingDetection Modality for Strategic Anti-Submarine Warfare

Thu, 01 May 2025 00:00:00 GMT

Assessing Quantum Magnetometry as an EmergingDetection Modality for Strategic Anti-Submarine Warfare Coy, Liam J. Emerging technologies have been a subject of much consternation in the nuclear deterrence communities as people fear they might erode secure second strike capabilities. One such emerging technology is the idea of ‘quantum magnetometry’—magnetic field sensors which use quantum principles in order to obtain more precise measurements. Nuclear submarines can be detected by the magnetic distortions they cause in the background Earth magnetic field. Quantum magnetometers could enable more precise measurements of such distortions. However, the lack of certainty around the potential for this emerging technology has led to a lack of clarity in policy circles. This thesis explores some limits on the impact of quantum magnetometry in the context of strategic anti-submarine warfare (ASW). It does this in two parts. First, it provides a survey of quantum magnetometry technologies and developments. Second, it characterizes the magnetic anomaly associated with a nuclear submarine (according to the best unclassified estimates of key parameters). It finds that while quantum magnetometers may indeed result in more sensitive magnetic anomaly detectors, their impact on strategic ASW will be limited. Firstly, the magnetic anomaly associated with a submarine scales as the inverse cube of the distance from the submarine. Thus, a ten-fold decrease in the minimum field necessary to detect a submarine would only provide a slightly more than two-fold increase in detection range. Improvements in detection range would have to be quite significant to have any strategic impact, due to the vast areas of the ocean required to search to find submarines. Secondly, magnetometers are limited by more factors than solely their sensitivity. There are signal processing issues involved in determining whether a change in measured magnetic field is as a result of a target or some form of environmental noise. As such, while quantum magnetometry may indeed improve submarine detection capabilities, it is unlikely to do so in a manner that impactfully destabilizes nuclear deterrence.

Evaluating the use of surface source banking to accelerate Monte Carlo transport simulations of far-field particle fluxes

Thu, 01 May 2025 00:00:00 GMT

Evaluating the use of surface source banking to accelerate Monte Carlo transport simulations of far-field particle fluxes Mowery, Eleni T. In order to enhance the verifiability and usability of surface source banking as a far-field flux and dose simulation acceleration method for Monte Carlo neutron transport codes, two surface source stationarity criteria were developed and evaluated. Surface sources were considered defined, or an accurate proxy for fission sources in eigenvalue simulations once enough particles have been banked such that these criteria were met. One criterion utilizes multi-dimensional Shannon entropy to indicate the stationarity of the surface source in physical space and energy. The other criterion uses functional expansions to track the stationarity of Legendre coefficients associated with spatially-dependent banked effective neutron reaction rates with different Z materials. The completion of a test case with an OpenMC model of an MK2 TRIGA facility indicated agreement between the two criteria. Effects of oversampling a surface source that met the stationarity criteria, as well as potential limitations of the surface source banking method itself were also examined via the test case.

Oppenheimer-Snyder Collapse in the BSSN Formalism

Thu, 01 May 2025 00:00:00 GMT

Oppenheimer-Snyder Collapse in the BSSN Formalism Leonard, Aidan J. In general relativity, problems with high degrees of symmetry often serve as illustrative simplifications of complicated scenarios. Oppenheimer-Snyder collapse, an exact solution for the gravitational collapse of a uniform, pressure-less ball of dust into a black hole, provides valuable insight into the collapse of realistic mass distributions such as stars. Early numerical relativity simulations demonstrated that a rotating ball of dust collapses into a Kerr black hole. In this thesis, we formulate the collapse of a slowly rotating dust-ball using the BSSN framework from numerical relativity, with the aim of reproducing this result in a simple manner. By perturbing the Oppenheimer-Snyder solution in isotropic coordinates, we find semi-analytic solutions to the constraint equations at linear order in angular momentum. In addition, we develop a Mathematica simulation code for modeling of spherical vacuum systems using the BSSN formalism. Diagnostics provide comparison of our results with theoretical predictions for the simplified case of a stationary black hole. Further work is required to introduce matter terms and move from spherical to axial symmetry.

Investigation of Ex-Situ Carbon Mineralization Fundamentals andScalability in Wet Supercritical Carbon Dioxide

Thu, 01 May 2025 00:00:00 GMT

Investigation of Ex-Situ Carbon Mineralization Fundamentals andScalability in Wet Supercritical Carbon Dioxide Fong, Andy With the world on average a degree Celsius warmer than the preindustrial 1850s, mitigating global warming is an urgent yet technically complex goal. Carbon mineralization, the trapping of carbon dioxide in the mineral phase via reaction with magnesium/calcium-rich silicates to form carbonates, is a promising method to offset carbon emissions. In addition to the reaction with carbon dioxide dissolved in water, these silicates have also been shown to be reactive with water-saturated (wet) supercritical carbon dioxide, but the rates are poorly constrained. In this study, we investigate the kinetics of carbonating olivine, a magnesium silicate-rich mineral, in wet supercritical carbon dioxide at 90 bars between 50 to 170 °C over time. We find that we can sufficiently model the complex dependence of olivine carbonation rates with a nucleation-crystallization mechanism for any temperature and grain size at 90 bars, although more data is necessary to confirm the model’s accuracy. Using our developed model, we predict that we can achieve near-complete carbonation at 300 °C using <10 micron olivine grains in a single day. Scaling of the process suggests that between 0.8 and 1.3 MWh is required per ton of carbon dioxide captured (via amine scrubbing) and sequestered as carbonates, depending on the energy source, which is comparable to recent carbon mineralization strategies such as those proposed by Carbfix. Furthermore, the silica and carbonate product can be utilized for various industrial applications totaling to an estimated $461 million for 0.7 megatons of carbon dioxide mineralized, which is Carbfix’s 2028 carbon capture goal. Alternatively, aquatic storage of sequestered carbon dioxide can enhance carbon sequestration by up to twofold, leading to between 0.4 and 1.3 MWh per ton of carbon dioxide captured and stored, although such an initiative would be economically inviable. We anticipate that large-scale carbon mineralization initiatives in the future need to be both effective and profitable for continued operation. Therefore, this initial evaluation of carbon mineralization in wet supercritical carbon dioxide reveals its environmental and economic viability at large scale. Application of wet scCO₂ carbonation to other minerals such as serpentine or basalt will ultimately require testing their competency to be carbonated in such conditions.

Globalizing “Humanism”: A Comparative Framework for Understanding Ethical and Literary Revivals Across Eurasia

Thu, 01 May 2025 00:00:00 GMT

Globalizing “Humanism”: A Comparative Framework for Understanding Ethical and Literary Revivals Across Eurasia Chen, Jason Humanism is often framed through the lens of Renaissance Europe, where classical revival and secular individualism defined a powerful cultural ideal. Yet similar movements—grounded in ethical self-cultivation, textual engagement, and educational reform—have emerged independently across diverse historical contexts. This study offers a comparative framework for understanding four such revivals: Confucian classicism in Tang and Song China, Byzantine paideia under the Palaiologos dynasty, Renaissance Italy’s metaphysical humanism, and the Arabic Nahda’s reformist thought in the colonial age. Each reflects a distinctive negotiation between inherited tradition, moral agency, and sociopolitical upheaval. Five core features recur across these cases: a belief in human ethical potential, reverence for classical texts, dialogue with religious orthodoxy, institutional mediation, and the emergence of a learned elite committed to public responsibility. Beginning with China and moving westward, the analysis disrupts conventional genealogies and recasts humanism as a plural, adaptive phenomenon. Figures such as Han Yu, Liu Zongyuan, Theodore Metochites, Giovanni Pico della Mirandola, and Rifa’a al- Tahtawi exemplify the variety of humanistic expression, each articulating a vision of ethical renewal suited to their cultural moment. Rather than advancing a fixed definition, the project treats humanism as a historically contingent mode of reflection on what it means to be human—one that emerges in response to crises of meaning, legitimacy, and identity. Across Eurasia, literary and intellectual revivals have served as means for societies to reimagine moral authority, reassert cultural identity, and envision more just forms of life. Reconsidering humanism in this way not only recovers overlooked traditions but enriches the vocabulary available for confronting contemporary challenges.

Lateral Transfer of DNA in Protocell-like Synthetic Cells

Thu, 01 May 2025 00:00:00 GMT

Lateral Transfer of DNA in Protocell-like Synthetic Cells Gray, Ryan J. Understanding how molecules could have moved between primitive cells is a central problem in Astrobiology and Geobiology. This thesis investigates whether electroporation can mediate the transfer of DNA into and between synthetic cells, potentially enabling gene expression in initially DNA-free compartments. Both TXTL and PURE-based cell-free expression systems were encapsulated in lipid in order to evaluate fluorescence as a proxy for GFP expression following electroporation across varying voltages and pulse numbers. In TXTL-based systems, increased fluorescence in electroporated conditions relative to controls supported the feasibility of environmental DNA uptake. PURE-based systems displayed similar trends, though variability in baseline fluorescence and fold-fluorescence complicated interpretation. In experiments designed to model lateral gene transfer (LGT) between synthetic donor and acceptor vesicles, modest fold changes in GFP expression were observed, particularly after multiple electroporation rounds, suggesting limited but detectable DNA transfer between vesicles. While microscopy provided some support for internal expression, its resolution and interpretability were strongly limited. Altogether, these findings support the concept that electroporation-like events such as those generated by lightning on early earth Earth could have promoted the horizontal movement of genetic material among protocells. Additionally, this work highlights key experimental challenges in modeling prebiotic genetic exchange, while also contributing to the development of synthetic biological systems that emulate early evolutionary processes.

Analyzing Environmental Tritium Cycle for Fusion Energy and National Security

Thu, 01 May 2025 00:00:00 GMT

Analyzing Environmental Tritium Cycle for Fusion Energy and National Security Arias, Liliana R. Although tritium is a sought-after isotope of hydrogen for fusion fuel, it is important to consider the environmental impacts of its release into the environment. In order to prepare for the elevated tritium releases that may result from commercial fusion power, yearly tritium releases from different types of nuclear facilities are compiled, with an emphasis on fusion reactors. Atmospheric modeling using HYSPLIT and a Gaussian Plume model is then conducted in order to better understand current and future global tritium sources and concentrations and their release pathways in the environment. Despite elevated tritium levels near major sources, most emissions remained within regulatory bounds, although proximity to facilities still matters.

Transient Grating Spectroscopy: Compact System Geometry Developments and Improved Software

Thu, 01 May 2025 00:00:00 GMT

Transient Grating Spectroscopy: Compact System Geometry Developments and Improved Software Rajagopal, Jonas A. Transient grating spectroscopy (TGS) is a rapid, non-destructive technique for measuring the thermal, elastic, and acoustic properties of the top several microns of a reflective surface. It has uses across many areas of materials research. Current TGS systems require complex optics tables taking up cumbersome amounts of space, restricting TGS to a predominantly lab-based method. This thesis first outlines a new design for TGS systems: an asymmetric probe, planar (APP) geometry, which enables TGS to be shrunk and simplified, lowering the barrier to entry and allowing for wider adoption in labs and industry. This Mini-TGS system was benchmarked against an existing system on a single-crystal tungsten sample, showing it produces the same SAW frequency as the benchmark system. The design enables TGS to be more widely adopted for use in more varied and compact environments because of its smaller size and simplicity. This thesis then outlines a study of reactor pressure vessel (RPV) coupons aimed at further understanding how properties evolve as a function of time in a reactor, as a step towards demonstrating that TGS can reliably detect if an RPV is fit for service. Ultimately, this work unveiled problems in the TGS fitting code. Lastly, this thesis details the software changes to the general TGS fitting code made to improve the fitting code in response to the RPV study.

Oceans, like highways

Thu, 01 May 2025 00:00:00 GMT

Oceans, like highways Kang, Emily This coming-of-age screenplay of loss, forced confrontation of one’s past, and self-discovery tracks a young female protagonist who runs away from a life in her family’s touring circus. Her story begins in a vivid, unorthodox environment and moves into a more mundane setting as she builds a life of her own, navigating the world outside the circus and away from her family. Through a series of trial and error, she pursues a career in journalism, seeking to honestly tell the stories of others. Eventually, she is presented with an opportunity that seems perfect in almost all dimension— except this commission requires her to confront her own story rather than deferring to those of others. The thesis aims to explore a story of emergence from the enclosed bubble of one environment to the entrance into a reality where only some of the prior rules now apply. The protagonist explores the question of how to reconcile with one’s past when forced to, despite her best attempts to avoid doing so. Through the many possible lenses to think about a past lifetime— nostalgia, gratitude, regret, among so many others— this story grapples with who we are in the midst of leaving everything we know behind, and how we process our past experiences while in a new stage of our lives.

Modeling Mesoscale Eddies: the Effects of Resolution onOcean Turbulence

Thu, 01 May 2025 00:00:00 GMT

Modeling Mesoscale Eddies: the Effects of Resolution onOcean Turbulence Brock, Lucy We describe a non-adiabatic idealized model for studying mesoscale turbulence in the global ocean. Using the ocean model Oceananigans, we perform a grid refinement study to determine the minimal resolution required to represent mesoscale eddies in the primitive equations. Convergence is evaluated through several metrics, including surface and depth-integrated kinetic energy, spectra, and zonally-averaged temperature, in order to establish quantitative resolution thresholds for physical fidelity. We find that while coarse-resolution simulations capture large-scale flow features, key mesoscale dynamics—including vertical stratification gradients and kinetic energy spectra—only converge at resolutions finer than 1/4°. Differences between the 1/8° and 1/16° simulations are small, suggesting that 1/8° resolution may be sufficient for resolving the mesoscale eddy field for many diagnostic purposes in idealized setups.

Triple oxygen isotope measurements in chert: insights into the Snowball Earth glaciations

Thu, 01 May 2025 00:00:00 GMT

Triple oxygen isotope measurements in chert: insights into the Snowball Earth glaciations Freudenburg-Puricelli, Markey Snowball Earth events represent a critical component of the history of the planet, particularly for the trajectory of life, atmospheric oxygen, and planetary habitability. There remains a myriad of questions about the dynamics of these global glaciations, especially regarding the relationship between the cryosphere and hydrosphere during this time. This study analyzes silica precipitates within a carbonate sequence immediately underlying a Cryogenian diamictite to better understand this relationship, particularly the chemistry of subglacial meltwater. Using triple oxygen isotope measurements, clumped isotope palaeothermometry, uranium-lead geochronology, and SEM/EDS and XRD analyses, we present interpretations of both the host rock and possible scenarios for the geochemistry of the precipitating fluid(s) responsible for these silica cements. We posit that these cherts are precipitates either from syn-glacial, sub-ice meltwaters or deglacial fluids from the end of the Marinoan glaciation, providing useful insights into the chemical composition of these source waters and demonstrating the utility of chemical precipitates as a record of ancient sub-ice conditions.

Method for Recharge and Sustainable Groundwater Use Estimation Using Soil Moisture Time-Series Analysis

Thu, 01 May 2025 00:00:00 GMT

Method for Recharge and Sustainable Groundwater Use Estimation Using Soil Moisture Time-Series Analysis Kummel, Kathryn Accurately estimating groundwater recharge is essential for sustainable aquifer management, yet remains difficult to measure directly, especially at large spatial scales. This thesis presents a method to estimate recharge using soil moisture drydown dynamics—the period following precipitation during which soil water is lost to evaporation and drainage. A two-component continuous loss function was developed to model this moisture loss, separating evaporation and drainage processes in a physically consistent, mathematically tractable framework. Using high temporal resolution in situ data from the ARM Southern Great Plains site, the method was calibrated and validated, showing that daily or sub-daily data capture the full shape of the loss function. A key outcome was the derivation of a hydrologic length scale (λ) from precipitation and soil moisture data, enabling conversion of unitless drainage estimates into physically meaningful recharge fluxes (mm/day). The methodology was then applied to satellite-based soil moisture data from the SMAP mission and the combined SMAPSMOS product. Despite resolution and noise limitations, these datasets produced reasonable drainage estimates, and the combined product showed particular promise for capturing drydowns at global scale. The findings demonstrate that soil moisture observations—when analyzed with appropriate temporal resolution and physical modeling—can provide a scalable, remote sensing-based approach to estimating groundwater recharge worldwide.

Modeling Non-Rotational Ocean Circulation and Heat Distribution in Icy Moons

Thu, 01 May 2025 00:00:00 GMT

Modeling Non-Rotational Ocean Circulation and Heat Distribution in Icy Moons Nath, Anika Subsurface oceans beneath the ice shells of icy moons like Europa and Enceladus are considered promising environments for extraterrestrial life. Their long-term habitability depends on internal heating and efficient vertical heat transport to maintain liquid water beneath the surface. This study models vertical heat diffusion in a non-rotating ocean column to investigate thermal structure and energy balance in such systems. A one-dimensional numerical simulation was developed using temperature-dependent thermal conductivity and fixed Dirichlet boundary conditions, initialized with a linear temperature gradient from −10 K at the surface to +10 K at the base. Over 1000 time steps, the temperature profile became nonlinear, with a kink indicating the transition from ice to water. Despite fixed boundary temperatures, the interior warmed, and the average temperature rose to 2.84 K. This resulted from asymmetric conductivity: efficient heating from below and slow heat loss through the upper ice. These results illustrate how conductivity structure controls thermal evolution and ice shell stability on ocean worlds.

Monitoring Anthropogenic Carbon in Cape Cod Bay

Thu, 01 May 2025 00:00:00 GMT

Monitoring Anthropogenic Carbon in Cape Cod Bay Neithardt, Daina M. Coastal oceans are diverse regions which are highly important to human activity, coastal ecosystems, and carbon uptake. Parameters such as pH on the total scale (pHₜ), Dissolved Inorganic Carbon (DIC), and Total Alkalinity (TA) contribute to understanding the health of coastal waters such as Cape Cod Bay, yet are resource-intensive to measure and have little historical data in Cape Cod Bay. Seawater collected from Cape Cod Bay was analyzed for pHₜ, DIC, and TA and compared to historic data from the region. A multi-linear-regression was performed to create a model to predict the measured parameters of the carbon system. Predicted TA accurately matched the measured values for the open water of the bay, while performing less accurately for near-coast samples. DIC could be predicted for the open water, although not to the same degree of precision as TA, while pHₜ showed little correlation with the predictors. Additionally, analysis of historical data revealed an extensive aragonite desaturation event in Cape Cod Bay during fall 2021.

Multi-Tokamak Assessment of Modeled Temperature Profiles

Thu, 01 May 2025 00:00:00 GMT

Multi-Tokamak Assessment of Modeled Temperature Profiles Yanna, Kaitlyn M. This study validates the predictive capability of a newly formalized modeling workflow—referred to here as MAESTRO—developed by Dr. Pablo Rodríguez Fernández of the MIT Integrated Modeling Group by comparing simulated plasma temperature profiles with experimental data from three well-documented tokamak discharges: Holland (2011) [1], White (2014) [2], and Zagorski (2015) [3]. The validation study uses the iterative TRANSP and PORTALS transport solvers to achieve flux-matching and self-consistency between heat sources and transport. The experimental temperature and density profiles were used as a starting point for the analysis. Three different SAT rules were used (SAT3 [4], SAT2-EM [5], and SAT2-EM as implemented in ASTRA [6]) and the edge boundary conditions were perturbed ±15% to simulate experimental error. The resulting profiles were plotted against the experimental profiles to validate the model’s accuracy. The percent difference of the simulated and experimental stored energy across the three cases is calculated. The results establish confidence in MAESTRO’s predictive capabilities for predicting future tokamak performance, while identifying areas for model improvement.

Paleo-aridity records investigated through drip water chemistry in Lehman Caves, Nevada

Thu, 01 May 2025 00:00:00 GMT

Paleo-aridity records investigated through drip water chemistry in Lehman Caves, Nevada Knight, Rory S. In the Great Basin of the southwest United States, climate change is predicted to cause increased precipitation variability, making the future climate of the region uncertain. The paleoclimate record has direct examples of dramatic changes in water availability in this area, allowing for a comparison of precipitation changes and responses for the Great Basin. In Lehman Cave, Nevada, ten drips above actively-forming stalagmites were sampled monthly. Glass growth plates were also placed above three actively-forming stalagmites, allowing for the collection of new calcite growths. This project analyzed the samples for Mg/Ca, Sr/Ca, and U/Ca ratios to provide a comparison of the composition of calcite and the drip waters from which they precipitate. This will improve our understanding of the paleo-aridity of the Great Basin region, as well as provide useful context for the changing precipitation patterns expected with modern climate change.

Even Parity Perturbations of the Janis-Newman-Winicour Singularity

Thu, 01 May 2025 00:00:00 GMT

Even Parity Perturbations of the Janis-Newman-Winicour Singularity Black, Brennen J. In this paper we build upon previous works on odd-parity perturbations to the Janis-Newman-Winicour singularity by extending the analysis to even-parity perturbations. Perturbations to the metric can be decomposed using tensor spherical harmonics and Fourier decomposition, and are further reduced by gauge transformations. By calculating the Einstein field equations and the divergence of the stress-energy tensor, one obtains 8 independent radial equations for the first-order metric perturbations and scalar field perturbation. Through a suitable functional transformation, one can determine a coupled wave equation between a perturbing function and the scalar field, which is most naturally solved using numerical integration techniques. Following this analysis, we briefly discuss the notion of boundary conditions for a globally naked singularity which are essential to proposing a well-defined perturbation problem.

A study of traffic at Governor Square, Boston, with suggestions for its regulation

Mon, 01 Jan 1923 00:00:00 GMT

A study of traffic at Governor Square, Boston, with suggestions for its regulation Phisānsukhumwit, Phra. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1923

A study of the great meadows area Lexington, Massachusetts

Wed, 01 Jan 1958 00:00:00 GMT

A study of the great meadows area Lexington, Massachusetts Banks, Philip Oren. Thesis: B.S., Massachusetts Institute of Technology, Department of Geology and Geophysics, 1958

Erosion test on valve and turbine metals

Mon, 01 Jan 1923 00:00:00 GMT

Erosion test on valve and turbine metals Blackett, Sydney W.; Golding, Harold B. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1923

American medical views on England's National Health Service expressed in three American medical journals, 1948-1967

Sun, 01 Jan 1967 00:00:00 GMT

American medical views on England's National Health Service expressed in three American medical journals, 1948-1967 Schwarz, John Stanley. Thesis: B.S., Massachusetts Institute of Technology, Department of Humanities, 1967; Includes bibliographical references (leaves 70-72).

A reinvestigation of the preparation of 1-carbethoxy-3-hydroxy-2-piperidylacetic acid

Tue, 01 Jan 1957 00:00:00 GMT

A reinvestigation of the preparation of 1-carbethoxy-3-hydroxy-2-piperidylacetic acid Wolpers, Jürgen Paul. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1957; Includes bibliographical references (leaves 20-21).

Ion optics of an electrostatic lens

Tue, 01 Jan 1980 00:00:00 GMT

Ion optics of an electrostatic lens Hangst, Jeffrey Scott. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1980; Includes bibliographical references.

Design Theory for Channel-less, Low-Pressure, Pressure-Compensating Drip Emitters

Wed, 01 May 2024 00:00:00 GMT

Design Theory for Channel-less, Low-Pressure, Pressure-Compensating Drip Emitters Howarth, Julia G. Drip irrigation is a tool used to aid farmers in water scarce locations by offering a higher water efficiency than conventional methods. However, drip systems require larger energy input thus increasing capital and operating expenses posing a barrier to its adoption, specifically in lower-middle income countries (LMIC). Low-pressure drip irrigation (LPDI) has been proposed as a way to achieve water-efficient drip systems with reduced operating expenses. Another barrier to adoption is clogging within emitters that leads to increased maintenance costs and lifespan constraint of the system. To address this challenge, this thesis proposes a design theory for emitters that could be clog-resistant in addition to being low-pressure by removing the smallest hydraulic feature of conventional emitters, the channel. The designs proposed are ‘channel-less’ and replace the pressure-varying hydraulic resistance of the channel with hydraulic resistance stemming from offsetting the outlet of the emitter away from the center axis of the emitter pocket, which is where it is conventionally located. The design theory hypothesizes that as the flexible diaphragm deflects and begins to cover the offset outlet, the gap that flow is able to exit through decreases producing a hydraulic resistance that allows for a constant flow rate. To define this moment of activation, an analytical structural model is used to correlate diaphragm deflection with experimentally observed pressure-compensating (PC) regions for a series of emitters with varying lands depths and outlet positions. Experiments of nine channel-less emitters resulted in six emitters with PC capabilities and activation pressures as low as 0.4 bar and flow rates ranging from 1.3 - 1.8 L/hr. The knowledge of when activation occurs in a channel-less emitter will allow designers the ability to vary geometric parameters and create a low-pressure, channel-less (LPCL) emitter that reduces operating expenses and clogging related barriers against drip adoption.

An analysis of requirements for a road-rail commuting system

Tue, 01 Jan 1963 00:00:00 GMT

An analysis of requirements for a road-rail commuting system Anderson, Ray, 1918- Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1963; Includes bibliographical references (leaf 60).

An office building for Charleston, South Carolina

Wed, 01 Jan 1958 00:00:00 GMT

An office building for Charleston, South Carolina Maybank, Joseph. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1958; Includes bibliographical references (leaf 21).

Camus and the absurd

Thu, 01 Jan 1981 00:00:00 GMT

Camus and the absurd Dorn, Christopher Keith. Thesis: B.S., Massachusetts Institute of Technology, Department. of Humanities, 1981; Includes bibliographical references (leaf 90).

A petrologic study of the Peabody granite stock

Fri, 01 Jan 1909 00:00:00 GMT

A petrologic study of the Peabody granite stock Pearce, J. Stewart.; Robinson, Burr A. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1909

The design of a cane sugar plant

Tue, 01 Jan 1924 00:00:00 GMT

The design of a cane sugar plant Pozas, Emilio.; Stefani, Luis. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1924; Includes bibliographical references (leaf 53).

Design of a reinforced concrete theatre balcony cantilever originally of steel

Sat, 01 Jan 1927 00:00:00 GMT

Design of a reinforced concrete theatre balcony cantilever originally of steel Huang, Chia Jua. Thesis: B.S., Massachusetts Institute of Technology, Department of Architectural Engineering, 1927; Includes bibliographical references.

-A summer resort hotel- in Siam

Sat, 01 Jan 1938 00:00:00 GMT

-A summer resort hotel- in Siam Sobhit, Momluang. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1938; Includes bibliographical references (leaf 48).

A seacoast fort

Sat, 01 Jan 1938 00:00:00 GMT

A seacoast fort Rockwell, Matthew L. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1938; Includes bibliographical references.

A ski centre at Cardigan, New Hampshire

Sat, 01 Jan 1938 00:00:00 GMT

A ski centre at Cardigan, New Hampshire Purcell, William F. H. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1938; Includes bibliographical references (leaf 27).

A new city hall for Boston

Sat, 01 Jan 1938 00:00:00 GMT

A new city hall for Boston Noonan, John J. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1938

Design for a gothic church of five hundred sittings

Fri, 01 Jan 1897 00:00:00 GMT

Design for a gothic church of five hundred sittings LeBaron, F. N. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1897

Duty test on the centrifugal pumping unit, Springvale Pumping Station, Natick, Massachusetts

Sun, 01 Jan 1928 00:00:00 GMT

Duty test on the centrifugal pumping unit, Springvale Pumping Station, Natick, Massachusetts Yin, Cho-Lan.; Sharabata, Ahmed Osman. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1928

Housing for the elderly in Tewksbury, Massachusetts.

Fri, 01 Jan 1965 00:00:00 GMT

Housing for the elderly in Tewksbury, Massachusetts. Roman, George Anthony. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1965; Bibliography: leaf 26.

A normative model for the railroad freight car acquisition planning process.

Thu, 01 Jan 1976 00:00:00 GMT

A normative model for the railroad freight car acquisition planning process. Burton, Philip Marc. Thesis: Civ. E., Massachusetts Institute of Technology, Department of Civil Engineering, 1976; Bibliography: leaves 240-249.

A design of a club house for a country club

Sat, 01 Jan 1898 00:00:00 GMT

A design of a club house for a country club DeGolyer, Robert S. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1898

Optimum route location in an underdeveloped area

Tue, 01 Jan 1963 00:00:00 GMT

Optimum route location in an underdeveloped area Burke, James Eugene, 1920- Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1963; Includes bibliographical references (leaf 24).

An undergraduate dormitory for Massachusetts Institute of Technology

Wed, 01 Jan 1958 00:00:00 GMT

An undergraduate dormitory for Massachusetts Institute of Technology Warbuton, Ralph. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1958; Includes bibliographical references (leaves 34-35).

Ripon 1970, an academic redevelopment program

Wed, 01 Jan 1958 00:00:00 GMT

Ripon 1970, an academic redevelopment program Linde, Richard P. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1958; Includes bibliographical references (leaf 22).

Some methods of securing more effective selling through manufacturers' agents

Sat, 01 Jan 1949 00:00:00 GMT

Some methods of securing more effective selling through manufacturers' agents Jones, William R.; Lannamann, Robert J. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1949; Bibliography: leaves 127-128.

Design criteria for a medium-powered, dynamically converted radioisotopic power generator for terrestrial use.

Sun, 01 Jan 1978 00:00:00 GMT

Design criteria for a medium-powered, dynamically converted radioisotopic power generator for terrestrial use. Esser, Peter D. Thesis: B.S., Massachusetts Institute of Technology, Department of Nuclear Engineering, 1978; Includes bibliographical references.

Magnetic properties of samarium-cobalt and cobalt-platinum.

Thu, 01 Jan 1976 00:00:00 GMT

Magnetic properties of samarium-cobalt and cobalt-platinum. Ralph, Mark Jonathan. Thesis: B.S., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 1976; Includes bibliographical references.

An investigation of type H transformers

Thu, 01 Jan 1903 00:00:00 GMT

An investigation of type H transformers Potter, A. A. (Andrey Abraham), 1882-1979.; Obear, George Barrows. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1903

Design for the main building of a day school for girls

Sat, 01 Jan 1916 00:00:00 GMT

Design for the main building of a day school for girls Pattee, Elizabeth G. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1916

A new approach to the marketing of railroad services

Wed, 01 Jan 1936 00:00:00 GMT

A new approach to the marketing of railroad services Sharp, W. Bennett. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1936; Includes bibliographical references (leaves 120-121).

Design of a flexible system for roadside restaurants

Sat, 01 Jan 1938 00:00:00 GMT

Design of a flexible system for roadside restaurants Weese, Harry M. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1938; Includes bibliographical references.

A beauty establishment

Sat, 01 Jan 1938 00:00:00 GMT

A beauty establishment Thompson, Polly Povey. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1938; Includes bibliographical references (leaf 18).

1863 Virginia: A short story

Sat, 01 Feb 2025 00:00:00 GMT

1863 Virginia: A short story Green II, Kelvin The question that motivates “1863 Virginia: A short story” is rooted in interracial solidarity and whether it exists outside of a common enemy. During this time in U.S. history, free and enslaved black people; slave-owning and poor white people; and assimilated and resistant native people co-existed. The story follows Indi, a Pamunkey woman, and Abram – a self-liberated and formerly enslaved African man from White House plantation. Due to her tribe's Black Laws, Indi is exiled for giving birth to a child of a Black man. Abram loses the love of his life to his murderous master Mr. Lee and runs away from White House plantation where he stumbles across Indi, Baby Joseph, and another person Indi took in during her time in exile named Sophia. Slave catchers come to Indi’s home looking for Abram and she must decide whether she will give him up or defend him. The text seeks to understand the interior character of people surviving impossible realities while also staying true to the connection of human beings and nature. There is a character Mae, a horse, who expresses herself and the river Pamunkey, who speaks.

Nature of the union between benzidine colors and cellolose

Wed, 01 Jan 1890 00:00:00 GMT

Nature of the union between benzidine colors and cellolose Colins, William H. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1890

Investigation of the distribution of phosphorus and nitrogen in the products of modern milling

Wed, 01 Jan 1890 00:00:00 GMT

Investigation of the distribution of phosphorus and nitrogen in the products of modern milling Bragg, Lottie Almira. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1890; Includes bibliographical references (leaves 1-10).

An investigation of several methods of setting indigo vats

Wed, 01 Jan 1890 00:00:00 GMT

An investigation of several methods of setting indigo vats Bartlett, Spaulding. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1890

Oil of maize

Wed, 01 Jan 1890 00:00:00 GMT

Oil of maize Atwood, F. W. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1890; Includes bibliographical references (leaf 1).

The design of a mining plant for a silver-lead mine

Sat, 01 Jan 1916 00:00:00 GMT

The design of a mining plant for a silver-lead mine Loo, Pang Chieh. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1916

A comparison of the outstanding securities of the Virginian and the Norfolk and Western Railway Companies

Thu, 01 Jan 1948 00:00:00 GMT

A comparison of the outstanding securities of the Virginian and the Norfolk and Western Railway Companies Zsembik, Thomas G.; Virtue, William D. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1948; Bibliography: leaf 100.

Determination of silicon in commercial aluminum and the action of reagents upon the metal

Wed, 01 Jan 1890 00:00:00 GMT

Determination of silicon in commercial aluminum and the action of reagents upon the metal Du Pont, Pierre S. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1890; Includes bibliographical references.

Design of a cam and follower linear actuator for satellite optical systems

Sat, 01 Feb 2025 00:00:00 GMT

Design of a cam and follower linear actuator for satellite optical systems Brown, Darrell Optical systems for satellites are used to image and track the physical environment of earth from space. Where the optical system images can be controlled through the rotation and movement of the optical system. Optical alignment is achieved though linear actuators, which constrain different degrees of freedom of the optical system. Optical systems require precise alignment, meaning the linear actuators that align them must have precise resolutions. During satellite launch, the satellite experiences both high acceleration and large magnitude vibrations, which can damage equipment. Common precision actuation methods cannot meet the high stiffness required for these satellite linear actuators. A cam and follower linear actuator was designed to fulfill these stiffness and precision requirements. Through modeling the dynamic and kinematic interactions between the cam and follower, a cam shape was designed, and necessary materials were chosen. Next through analysis of process capabilities of available fabrication tools, manufacturing methods for different parts were selected. Finally, using components designed for testing, kinematic tests were conducted on the linear actuator. Testing of the actuator demonstrated it was capable of actuating with a precision of 9.15 microns. More testing is needed to understand the stiffness of the device.

Development of a computational tool and dynamometer for optimizing variable-speed centrifugal pump selection for a containerized, direct-drive photovoltaic electrodialysis desalination system

Sat, 01 Feb 2025 00:00:00 GMT

Development of a computational tool and dynamometer for optimizing variable-speed centrifugal pump selection for a containerized, direct-drive photovoltaic electrodialysis desalination system McWhinnie, Muriel A. This thesis presents an optimized centrifugal pump selection methodology to improve the hydraulic efficiency of MIT’s Global Engineering and Research (GEAR) Center’s containerized, direct-drive photovoltaic electrodialysis desalination system capable of producing up to 300m3 of potable water per day. The novel flow-commanded current control scheme of this containerized desalination plant (CDP), which enables its minimal energy storage, also means that the centrifugal pumps used are operated at variable speeds to respond to the solar irradiance. Unfortunately, centrifugal pumps are typically designed for fixed operating conditions, and manufacturers often only report pump performance at their rated frequency. By estimating the hydraulic resistances of the CDP and testing potential pumps on a redesigned dynamometer, a MATLAB-based tool was developed to quickly and iteratively characterize pump performance at their expected operating points in the CDP. A "Compatibility Factor" metric, defined by the normalized area under a pump’s efficiency-flow curve at its operating points, was devised to quantify each pump’s efficiency across the entire operating range of flow rates achievable under the CDP’s system constraints. Using this methodology, two 7.5 kW pumps were selected per diluate and concentrate channels to the electrodialysis stacks for alternate operation use. Following testing pumps on a dynamometer, this work outlines a methodology for characterizing a pump’s variable-speed efficiency at its operating points in any modeled system. This approach facilitates informed pump selection for the CDP to increase its water production and reduce its specific energy consumption, with an estimated improvement in hydraulic efficiency from 10% in GEAR Center’s previous system to over 30%. Overall, this work is applicable to various photovoltaic pumping systems aiming to reduce carbon emissions through variable-speed operation.

A model of flow through an aqueous vein

Tue, 01 Jan 1980 00:00:00 GMT

A model of flow through an aqueous vein Yuan, San Shing. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1980; Bibliography: leaf 44.

The kjeldahl nitrogen process for well waters

Wed, 01 Jan 1890 00:00:00 GMT

The kjeldahl nitrogen process for well waters Fuller, George W. (George Washington), 1868- Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1890

A study of brom and nitroso phenols

Wed, 01 Jan 1890 00:00:00 GMT

A study of brom and nitroso phenols Carney, James Andrew. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1890

Oxidation of olive oil by metal catalysts

Sat, 01 Jan 1921 00:00:00 GMT

Oxidation of olive oil by metal catalysts Hart, Morris. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1921; Includes bibliographical references (leaf 16).

An analytical study of the effects of vibrations on heat transfer from a heated horizontal cyclinder

Sun, 01 Jan 1961 00:00:00 GMT

An analytical study of the effects of vibrations on heat transfer from a heated horizontal cyclinder Chiang, Tom. Thesis: Mech. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1961; Includes bibliographical references (leaves 31-32).

Diffusion coefficients of styrene in mayonnaise and yogurt

Tue, 01 Jan 1980 00:00:00 GMT

Diffusion coefficients of styrene in mayonnaise and yogurt Huang, Wendy. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1980; Includes bibliographical references (leaf 74).

Tunability of Electrospun Scaffolds for Tissue Engineering

Fri, 01 May 2020 00:00:00 GMT

Tunability of Electrospun Scaffolds for Tissue Engineering Chyr, Gloria Un Electrospinning is a cheap and quick method of creating non-woven scaffolds for tissue regeneration and growth with the proper fiber diameter for cell adhesion. However, electrospun scaffolds lack large pores between fibers and result in a densely packed mesh in which cells can adhere only to the surface of the material. Control of scaffold fiber size and porosity is critical to ensure scaffolds have a fiber diameter appropriate for cell adhesion and a high-enough porosity to allow for cell migration through the material. This thesis aims to demonstrate the tunability and control of electrospun gelatin scaffolds to make them viable for use in tissue regeneration by altering grounded collector geometry and thus the electric field that nanofiber deposition follows. Previous electrospinning experiments show that processing parameters such as flow rate and voltage can affect fiber diameter and porosity, but are still insufficient in achieving dimensions viable for cell migration. Scaffold porosity is substantially more affected by the grounded collector geometry. By modifying collector geometry, pore size can be controlled without affecting fiber morphology and the deposition of gelatin nanofibers can be aligned or patterned to mimic natural tissue scaffolds. Introduction of a non-conductive, woven mesh in between the collector and source may allow further control of deposition patterns and thus scaffold construction. The path of electrospun fibers and the deposition patterns can be predicted by modeling the electric field.

Searching for Mixed Octahedral-Tetrahedral Interstitial Hydrogen Occupation in Pd-Ti Sublattices: A Computational Study

Fri, 01 May 2020 00:00:00 GMT

Searching for Mixed Octahedral-Tetrahedral Interstitial Hydrogen Occupation in Pd-Ti Sublattices: A Computational Study Metcalf, Isaac With hydrogen conversion and storage technologies promising a revolution in the energy industry if volumetric energy density is increased, the loading of hydrogen to high concentrations in metal lattices has become of special interest. Here we use Projector Augmented-wave density functional theory methods to search the Pd-Ti-H system for stable instances of mixed tetrahedral-octahedral site occupation. We compute the energies of 42 hydrides constructed from seven metal sublattices: Ni₃Ti-prototype Pd₃Ti, CdI₂-prototype PdTi₂, and FCC four-atom unit cells of Pd, Pd₃Ti, PdTi, PdTi₃, and Ti. Our results suggest that mixed octahedral-tetrahedral occupation is energetically unfavorable in most cases, but a Li₃Bi-prototype hydride may be stable within the Pd₁-ₓTiₓH₃ system.

Sanitary design for Hopeworth Sanitarium

Sun, 01 Jan 1911 00:00:00 GMT

Sanitary design for Hopeworth Sanitarium Eli, Carl Stephens.; Babbitt, Harold E. 1888-1970. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil and Sanitary Engineering, 1911

A study of the electrification of the suburban zone of the New York, New Haven and Hartford Railroad centering in Boston

Thu, 01 Jan 1920 00:00:00 GMT

A study of the electrification of the suburban zone of the New York, New Haven and Hartford Railroad centering in Boston Bancker, Elbert H.; Bangratz, Ernest George.; Becker, James H. 1894-1970.; Farist, Charles J.; Moore, Irwin L. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1920; Appendix contains numerous pamphlets.

Initial investigation of the relation between the mode of MHD current transport and the near-electrode boundary layers

Fri, 01 Jan 1982 00:00:00 GMT

Initial investigation of the relation between the mode of MHD current transport and the near-electrode boundary layers Daentl, Wyatt S. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1982; Includes bibliographical references.

A computer controlled fluid supply system

Fri, 01 Jan 1982 00:00:00 GMT

A computer controlled fluid supply system Curtis, Kent Wesley. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1982; Bibliography: leaf 37.

Organic chemistry laboratory

Sat, 01 Jan 1881 00:00:00 GMT

Organic chemistry laboratory Lindsay, William B., 1858- Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1881

Work in organic laboratory

Tue, 01 Jan 1878 00:00:00 GMT

Work in organic laboratory Stantial, Frank G. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1878

Notes on the preparation of: alcohol absolute, ethyl bromide, ethyl iodide, acetyl chloride, ethyl amines, zinc ethyl, chloral, trichloracetic acid

Wed, 01 Jan 1879 00:00:00 GMT

Notes on the preparation of: alcohol absolute, ethyl bromide, ethyl iodide, acetyl chloride, ethyl amines, zinc ethyl, chloral, trichloracetic acid Macfarlane, Wm. W. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1879

Report on work done in the organic laboratory

Wed, 01 Jan 1879 00:00:00 GMT

Report on work done in the organic laboratory Allen, Walter S. (Walter Spooner) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1879

Report of work in organic laboratory

Tue, 01 Jan 1878 00:00:00 GMT

Report of work in organic laboratory Woolworth, J. G. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1878

The wind resistance of ships

Sat, 01 Jan 1916 00:00:00 GMT

The wind resistance of ships Ober, Shatswell, 1894- Thesis: B.S., Massachusetts Institute of Technology, Department of Naval Architecture and Marine Engineering, 1916

A fast response instrument to directly read the ratio of two electrical signals

Fri, 01 Jan 1960 00:00:00 GMT

A fast response instrument to directly read the ratio of two electrical signals Shaw, Edward Eugene. Thesis: B.S., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 1960; Includes bibliographical references (leaf 26).

A compilation of phenomenological methods to solve mesonic problems without a "meson theory"

Fri, 01 Jan 1954 00:00:00 GMT

A compilation of phenomenological methods to solve mesonic problems without a "meson theory" Tarimer, Niyazi. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1954

Stree-rupture properties of beryllium and a beryllium-nickel alloy

Tue, 01 Jan 1952 00:00:00 GMT

Stree-rupture properties of beryllium and a beryllium-nickel alloy Rapperport, Eugene J. (Eugene John); Gelles, Stanley H. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1952; Includes bibliographical references (leaf 22).

Comparison of machining and tensile test data of low carbon steel.

Mon, 01 Jan 1945 00:00:00 GMT

Comparison of machining and tensile test data of low carbon steel. Sevand, Ali Hikmet. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1945; Bibliography: leaves 30-31.

Reorganization and documentation of a motor unit decomposition program

Fri, 01 Jan 1982 00:00:00 GMT

Reorganization and documentation of a motor unit decomposition program Creigh, John Lock. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1982; Bibliography: leaf 150.

Report on work done in the organic laboratory

Sat, 01 Jan 1881 00:00:00 GMT

Report on work done in the organic laboratory Lund, James. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1881

A compilation of notes on steam pumps

Fri, 01 Jan 1875 00:00:00 GMT

A compilation of notes on steam pumps Sargent, F. T. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1875

Treatment of vershire copper ore

Mon, 01 Jan 1877 00:00:00 GMT

Treatment of vershire copper ore Southworth, Harry C. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1877

An investigation and report on the Pomeroy Iron Works at West Stockbridge, Mass.

Sat, 01 Jan 1876 00:00:00 GMT

An investigation and report on the Pomeroy Iron Works at West Stockbridge, Mass. Schwarz, Theodore E. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1876

West Boston Draw

Sat, 01 Jan 1876 00:00:00 GMT

West Boston Draw Rich, C. L. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1876

Nitro-substitution products of benzole

Sat, 01 Jan 1881 00:00:00 GMT

Nitro-substitution products of benzole Briggs, Franklin H. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1881; Includes bibliographical references (leaves 26-27).

Report of work done in the organic chemical laboratory

Tue, 01 Jan 1878 00:00:00 GMT

Report of work done in the organic chemical laboratory Morgan, Frank H. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1878

A family of curves for the geometric mean distance of one rectangle from another

Sat, 01 Jan 1944 00:00:00 GMT

A family of curves for the geometric mean distance of one rectangle from another Uluant, Cemal Ali. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1944; Includes bibliographical references (leaves [25]-26).

Fresnoite examined by circularly polarized Raman scattering.

Sun, 01 Jan 1978 00:00:00 GMT

Fresnoite examined by circularly polarized Raman scattering. Chieu, Trieu Can. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1978; Includes bibliographical references.

Analysis and design of a rotary compressor

Sun, 01 Jan 1978 00:00:00 GMT

Analysis and design of a rotary compressor Cheimets, Peter Norman. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1978; Bibliography: leaf 67.

Riveted lattice bridge

Tue, 01 Jan 1878 00:00:00 GMT

Riveted lattice bridge Ritchie, James, 1882- author. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1878; Manuscript.

Cotton manufacture and the ring frame / by H.M. Silsbee.

Thu, 01 Jan 1874 00:00:00 GMT

Cotton manufacture and the ring frame / by H.M. Silsbee. Silsbee, H. M., author. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1874; Manuscript.

The results of an experiment on cylinder condensation, using steam superheated to a temperature of 590⁰F. with a pressure of 70 lbs. per sq. in. - the apparent cut-off at the front end being 4.38/20 ths. and at the crank end 4.18/20 / Thos. D. Plimpton.

Fri, 01 Jan 1875 00:00:00 GMT

The results of an experiment on cylinder condensation, using steam superheated to a temperature of 590⁰F. with a pressure of 70 lbs. per sq. in. - the apparent cut-off at the front end being 4.38/20 ths. and at the crank end 4.18/20 / Thos. D. Plimpton. Plimpton, Thos. D. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1875

A few notes on governors and their principles of action

Fri, 01 Jan 1875 00:00:00 GMT

A few notes on governors and their principles of action Lewis, Wilfred. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1875

Locomotives

Fri, 01 Jan 1875 00:00:00 GMT

Locomotives Stanwood, J. B. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1875

A discussion on the construction of gear teeth

Fri, 01 Jan 1875 00:00:00 GMT

A discussion on the construction of gear teeth Hibbard, Tom, 1947- Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1875

The expansion of saturated steam

Fri, 01 Jan 1875 00:00:00 GMT

The expansion of saturated steam Head, James H., -1869. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1875

The working of 5668 lbs. third grade and 1147 lbs. 1st grade argentiferous galena ore from the Merrimac Mine, Newburyport, Mass., including crushing, washing, roasting, and smelting of the ore and refining the products obtained

Tue, 01 Jan 1878 00:00:00 GMT

The working of 5668 lbs. third grade and 1147 lbs. 1st grade argentiferous galena ore from the Merrimac Mine, Newburyport, Mass., including crushing, washing, roasting, and smelting of the ore and refining the products obtained Towne, Linwood O. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1878

The vershire copper ore and its metallurgical treatment

Mon, 01 Jan 1877 00:00:00 GMT

The vershire copper ore and its metallurgical treatment Bartol, George. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1877

Steel

Sat, 01 Jan 1876 00:00:00 GMT

Steel Hunt, Alfred E. (Alfred Ephraim), 1855-1899. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1876

The Hancock Inspirator

Tue, 01 Jan 1878 00:00:00 GMT

The Hancock Inspirator Schwamb, Peter, 1858-1928. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1878

Pumping engines

Sat, 01 Jan 1876 00:00:00 GMT

Pumping engines Kilham, A. C. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1876

Study of the alcohol thermometer at low temperatures

Sun, 01 Jan 1882 00:00:00 GMT

Study of the alcohol thermometer at low temperatures White, Anthony C. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1882

On the Columbus Avenue Bridge, Boston, Mass.

Tue, 01 Jan 1878 00:00:00 GMT

On the Columbus Avenue Bridge, Boston, Mass. Kebler, Julian A. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1878

The Ashtabula Bridge

Mon, 01 Jan 1877 00:00:00 GMT

The Ashtabula Bridge Wiggin, Frank E. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1877

A wrought iron post - truss

Sat, 01 Jan 1876 00:00:00 GMT

A wrought iron post - truss Raeder, Henry. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1876

The Albany Street Bridge

Sat, 01 Jan 1876 00:00:00 GMT

The Albany Street Bridge Hodgdon, F. W. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1876

The Broadway Draw Bridge, Boston, Mass.

Sat, 01 Jan 1876 00:00:00 GMT

The Broadway Draw Bridge, Boston, Mass. Freeman, John R., 1950- Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1876

The Front Street Bridge in Worcester, Mass.

Sat, 01 Jan 1876 00:00:00 GMT

The Front Street Bridge in Worcester, Mass. Copeland, Fred K. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1876

A review of the Buffalo Water Supply

Sat, 01 Jan 1876 00:00:00 GMT

A review of the Buffalo Water Supply Buttolph, H. T. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1876

West Chester Park Bridge over B. & P. R.R. in Boston

Sat, 01 Jan 1876 00:00:00 GMT

West Chester Park Bridge over B. & P. R.R. in Boston Breed, Joshua B. F. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1876

Merrimac River Bridge

Sat, 01 Jan 1876 00:00:00 GMT

Merrimac River Bridge Baldwin, Thomas W. (Thomas Williams), 1849- Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1876

A comparison of the different methods of determining carbon and graphite in cast irons and steels of volumetric methods for determining iron in irons steels and iron ores and notes on Meinickes process for determining sulphur and phosphorus in cast irons and steels

Mon, 01 Jan 1877 00:00:00 GMT

A comparison of the different methods of determining carbon and graphite in cast irons and steels of volumetric methods for determining iron in irons steels and iron ores and notes on Meinickes process for determining sulphur and phosphorus in cast irons and steels Pope, Thomas E. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1877

A report of work in the organic laboratory

Tue, 01 Jan 1878 00:00:00 GMT

A report of work in the organic laboratory Allbright, William B. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1878

A study of the possibility of using low voltage A. C. on the third rail system entering the Pennsylvania terminal

Fri, 01 Jan 1926 00:00:00 GMT

A study of the possibility of using low voltage A. C. on the third rail system entering the Pennsylvania terminal Maschi, A. P.; Driscoll, J. J. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1926

Design for a town hall

Tue, 01 Jan 1878 00:00:00 GMT

Design for a town hall Baker, Charles M. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1878

A steam fire engine house

Mon, 01 Jan 1877 00:00:00 GMT

A steam fire engine house Chamberlin, William E. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1877

The experimental working by wet and dry methods, of a low grade silver and gold ore from Newburyport, Mass.

Mon, 01 Jan 1877 00:00:00 GMT

The experimental working by wet and dry methods, of a low grade silver and gold ore from Newburyport, Mass. Wood, F. W. (Floyd William), 1926- Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1877

The Swain Turbine

Thu, 01 Jan 1874 00:00:00 GMT

The Swain Turbine Barrus, George Hale. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1874

The Corliss Steam Engine

Thu, 01 Jan 1874 00:00:00 GMT

The Corliss Steam Engine Pond, Frank H. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1874

Experimental treatment of side products formed in smelting the silver lead ore of Newburyport, Mass.

Mon, 01 Jan 1877 00:00:00 GMT

Experimental treatment of side products formed in smelting the silver lead ore of Newburyport, Mass. Baldwin, G. J. (George Johnson); Hibbard, Henry D. 1856- Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1877

The Port Henry Iron Industry

Sat, 01 Jan 1876 00:00:00 GMT

The Port Henry Iron Industry Allen, C. F. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1876

History of musical pitch and its present condition in Boston

Thu, 01 Jan 1880 00:00:00 GMT

History of musical pitch and its present condition in Boston Miller, Wm. T. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1880

Experiments with Holtz machine

Fri, 01 Jan 1875 00:00:00 GMT

Experiments with Holtz machine Mixter, S. J., 1855-1926. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1875

The mean specific gravity of the earth

Sat, 01 Jan 1876 00:00:00 GMT

The mean specific gravity of the earth Henck, J. B. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1876

The Newton Water Works

Mon, 01 Jan 1877 00:00:00 GMT

The Newton Water Works Plimpton, A. L. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1877

Design for iron railway bridge

Tue, 01 Jan 1878 00:00:00 GMT

Design for iron railway bridge Nichols, E. J. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1878

Design for an iron railway bridge, with a consideration of the principles determining the design

Mon, 01 Jan 1877 00:00:00 GMT

Design for an iron railway bridge, with a consideration of the principles determining the design Swain, Geo. F. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1877

Dover Street Draw-Bridge

Mon, 01 Jan 1877 00:00:00 GMT

Dover Street Draw-Bridge Stewart, Charles E. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1877

Evaluation of electromagnetic interference fringes for two-layer media.

Sun, 01 Jan 1978 00:00:00 GMT

Evaluation of electromagnetic interference fringes for two-layer media. Chew, Weng Cho. Thesis: Elec. E., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1978; Includes bibliographical references.

A scientific academy

Tue, 01 Jan 1878 00:00:00 GMT

A scientific academy Eaton, Charles S., 1838-1896. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1878

Electrophilic C(sp²)–H Cyanation with Inorganic Cyanate (OCN⁻) by Pᴵᴵᴵ/Pⱽ=O-Catalyzed Phase Transfer Activation

Wed, 01 May 2024 00:00:00 GMT

Electrophilic C(sp²)–H Cyanation with Inorganic Cyanate (OCN⁻) by Pᴵᴵᴵ/Pⱽ=O-Catalyzed Phase Transfer Activation Hu, Shicheng A catalytic method for the direct electrophilic cyanation of C(sp²)–H nucleophiles with sodium cyanate (NaOCN) is reported. Mechanistic experiments show that under solid-liquid phase transfer, an inorganic cyanate is activated by halide displacement on a halophosphonium. Redox catalysis is enabled by the usage of a strained phosphine (phosphetane) so that catalyst turnover from phosphine oxide to phosphine can be easily achieved by the usage of a terminal hydrosilane reductant. These results demonstrate the feasibility of deoxyfunctionalization of insoluble inorganic salts by Pᴵᴵᴵ/Pⱽ=O catalyzed phase transfer activation, as exemplified by C(sp²)–H cyanation with NaOCN as the “CN⁺” source.

Steam boilers

Sat, 01 Jan 1876 00:00:00 GMT

Steam boilers Dennett, C. L. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1876

Locomotive engineering

Sat, 01 Jan 1876 00:00:00 GMT

Locomotive engineering Galloupe, Francis E. (Francis Ellis) Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1876

The efficiency of marine engines

Sat, 01 Jan 1876 00:00:00 GMT

The efficiency of marine engines Main, Charles T. (Charles Thomas), 1856-1943. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1876

Treatment of vershire copper ore

Tue, 01 Jan 1878 00:00:00 GMT

Treatment of vershire copper ore Adams, W. W. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1878

Explanations and calculations accompanying a thesis design for a town hall

Mon, 01 Jan 1877 00:00:00 GMT

Explanations and calculations accompanying a thesis design for a town hall Capen, G. W. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1877

Report on the working for silver and gold of a middle grade product from ore of the Merrimac Mine, Newburyport

Mon, 01 Jan 1877 00:00:00 GMT

Report on the working for silver and gold of a middle grade product from ore of the Merrimac Mine, Newburyport Jenney, Walter. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1877

The colors of our common lights

Wed, 01 Jan 1879 00:00:00 GMT

The colors of our common lights Pickering, Wm. H. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1879

New experiments in sound

Sat, 01 Jan 1876 00:00:00 GMT

New experiments in sound Jacques, William W., 1855-1932. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1876

The electrodeposition of iron from perchlorate solutions

Sat, 01 Jan 1921 00:00:00 GMT

The electrodeposition of iron from perchlorate solutions Johnson, Algot J. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrochemical Engineering, 1921; Includes bibliographical references (leaves 40-41).

Compilation of general descriptions and data of pumps manufactured in the United States

Wed, 01 Jan 1947 00:00:00 GMT

Compilation of general descriptions and data of pumps manufactured in the United States Zaworski, Robert Joseph.; Anderson, Donald E. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1947; Bibliography: leaves [1-15].

Loss of dignity : social dangers of a computerized society

Thu, 01 Jan 1976 00:00:00 GMT

Loss of dignity : social dangers of a computerized society Yablon, Jay Russell. Thesis: B.S., Massachusetts Institute of Technology, Department of Political Science, 1976; Includes bibliographical references (leaves 201-206).

Short term distortion in dynamic noise-filters.

Thu, 01 Jan 1976 00:00:00 GMT

Short term distortion in dynamic noise-filters. Wright, John Nelson. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1976; Includes bibliographical references.

Thermodynamic and heat transfer evaluation of a thermic solar panel

Thu, 01 Jan 1976 00:00:00 GMT

Thermodynamic and heat transfer evaluation of a thermic solar panel Yasuda, Arthur Kenichi. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1976; Includes bibliographical references.

Actuated Poppet Hydrogen Peroxide Reactor

Wed, 01 May 2024 00:00:00 GMT

Actuated Poppet Hydrogen Peroxide Reactor Kirkman, Josef X. This thesis discusses the design and characteristics of an actuated poppet valve hydrogen peroxide and silver catalyst reactor that can be used to generate compressed gas to use for self-powered robotic systems. The reactor’s poppet valve conceals and reveals the silver catalyst to control the reaction. The sealing performance of the valve at working pressures are crucial to the accurate control of the reactor itself. This thesis discusses various design variations of the sealing poppet head and how they can improve performance given various design goals.

Some experiments on the volatile oil of the Myrcia Acris

Mon, 01 Jan 1877 00:00:00 GMT

Some experiments on the volatile oil of the Myrcia Acris Fish, Chas. C. R. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1877

Anthracene, and its isomer, phenanthrene, and their derivatives; with a short investigation of the methods for the quantitative estimation of phenanthrene and anthracene

Sat, 01 Jan 1876 00:00:00 GMT

Anthracene, and its isomer, phenanthrene, and their derivatives; with a short investigation of the methods for the quantitative estimation of phenanthrene and anthracene Fletcher, Chas. R. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1876

Terminal problem of an industrial railroad

Thu, 01 Jan 1925 00:00:00 GMT

Terminal problem of an industrial railroad Lyons, H. M.; Lucy, E. D. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1925; Includes bibliographical references (leaves 23-25).

Characteristics of epoxy resin-kaolinite compositions

Tue, 01 Jan 1957 00:00:00 GMT

Characteristics of epoxy resin-kaolinite compositions Waugh, George H.; Feldman, Marnin. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1957; Bibliography: leaf 36.

Experimental verification of breeding performance of fast reactor blankets.

Thu, 01 Jan 1976 00:00:00 GMT

Experimental verification of breeding performance of fast reactor blankets. Wu, Shin-Shyong. Thesis: Nuc. E., Massachusetts Institute of Technology, Department of Nuclear Engineering, 1976; Bibliography: leaves 154-158.

Geology of Eastern Massachusetts

Sat, 01 Jan 1876 00:00:00 GMT

Geology of Eastern Massachusetts Crosby, William O. (William Otis), 1850-1925. Thesis: B.S., Massachusetts Institute of Technology, Department of Geology, 1876

Towards Mindful Consumption

Wed, 01 May 2024 00:00:00 GMT

Towards Mindful Consumption Covarrubias, Juliana Humanity is using up more of the Earth's resources than the planet can replenish each year. The unsustainable rate at which humanity is depleting the Earth's resources threatens the viability of our current lifestyles, posing significant challenges for future generations. Further, it places a heavy burden on the planet, resulting in several environmental problems, most notably climate change. Many approaches to combating climate change focus on lessening the impact of our current living habits on the Earth. Popular initiatives involving biodegradability, recycling, and carbon offsetting seek to reduce the effects of pollution while allowing humanity to keep consuming products at the same rate. Alternatively, reducing the production of these goods in the first place eliminates the need for such anti-pollution interventions downstream. This thesis considers climate change at one of its sources: overconsumption. The thesis examines the history of consumer culture to identify the causes of our current excessive consumption patterns. Through analyzing the influences that advertising and culture have on our behavior, this thesis aims to demystify and uncover the power we have over our actions as consumers. The final output of this thesis is a handwritten book of thoughts and sketches that is distributed around the public sphere to provoke conversations about our individual relationships with consumerism. These discussions may have broader implications as they spread and lead to behavioral shifts towards more mindfully consumerist lifestyles. Ultimately, this thesis uses a dialogue with itself to plant a seed challenging the status quo of overconsumption, catalyzing meaningful discussion about our responsibilities, behaviors, and concerns in a consumption-driven world.

Tools for Togetherness: Building Social Networks through Public Tool-making

Wed, 01 May 2024 00:00:00 GMT

Tools for Togetherness: Building Social Networks through Public Tool-making Liu, Yanjun Emily Our world appears connected with pervasive technology and information saturation. However, beneath the surface, a deep sense of disconnection and individualism persists, exacerbated by the COVID-19 pandemic, which claimed 7 million lives and prompted a reassessment of our societal values towards more collective orientations. This thesis investigates how individuals can help foster a society that values care, support, and mutual aid. By developing, documenting, and disseminating self-organized public tools—including flyers, posters, and installations that facilitate relationship-building—this work aims to challenge the prevailing alienation by demonstrating the importance of connectivity and exchange. Embedding mutual support and connectivity into daily routines should not merely be a contingency for crises but a fundamental component of our reality. The essence of this project is to disseminate this concept through public engagement installation art within the MIT and greater Cambridge community to cultivate awareness and actively engage the audience. The book details three social experiments designed to enhance connectivity and mutual support, with detailed documentation and reflections from a facilitator’s perspective on the complete process for anyone who hopes to start practicing small.

Moving Sculptures: Animating the Human Body in Stop-Motion WithPolymer Clay

Wed, 01 May 2024 00:00:00 GMT

Moving Sculptures: Animating the Human Body in Stop-Motion WithPolymer Clay Smerekanych, Eva B. The purpose of this thesis is to explore novel approaches to stop-motion animation techniques and design and sculpt an original moveable clay figure utilizing those techniques. This thesis focuses on animating human anatomy, testing the extreme physical and emotional states that can be portrayed within the medium of a stop-motion film. Stop-motion animation is a technique wherein a film is shot frame by frame, with animators manually moving characters between each frame to create a sense of movement when the frames are played back sequentially. While there are many possible approaches to producing stop-motion animation, this thesis focuses entirely on hand-sculpted clay animation, due to the tactile nature of the medium and the artistic expression it allows. The motivation for this study is to find a way to bring sculptures to life in a way that does not sacrifice attention to detail. Over the course of this study, a series of experiments were carried out, each testing a different approach to claymation character design. Each experiment culminated in a short stop-motion clip demonstrating the unique design approach. The result of this thesis is a novel design for a moveable clay figure which is used as the main character in an original stop-motion short film. This thesis explores the entire design process behind creating a moveable clay sculpture, including all challenges and considerations that played a role in informing the final figure design.

Enhancing Music Interfaces with Soft Materials

Wed, 01 May 2024 00:00:00 GMT

Enhancing Music Interfaces with Soft Materials Yañez-Laguna, Diego Despite the growing popularity of digital music instruments (DMIs) and relevant technological advances, accessibility and expressive potential remain significant challenges for musical interface designers. These issues stem from generic input-output mappings, sensor limitations, and a lack of physical connection between musicians and instruments. This thesis examines the benefits of incorporating soft materials into musical interfaces and why DMIs should be designed with musician-instrument relationships as a priority in order to enhance intuitiveness and expressiveness. This work culminates with design and analysis of a prototype that explores the potential of a foam user interface. Featuring pressure sensors embedded within foam blocks, the prototype encourages tactile interaction and gives the user nuanced control over various musical parameters. The modular design of the foam blocks allows for versatile configurations, enabling users to control multiple parameters simultaneously with simple, but responsive gestures.

Computational Exploration of Origami Tessellation Design:Harnessing Shape Grammar for Flexible Folding Structures

Wed, 01 May 2024 00:00:00 GMT

Computational Exploration of Origami Tessellation Design:Harnessing Shape Grammar for Flexible Folding Structures Qiu, Lingyi Origami tessellation, with its intricate folding patterns, presents a unique blend of artistic expression and engineering application. However, the design process often proves daunting due to its complexity, limiting accessibility to enthusiasts and impeding its potential impact in engineering and architecture fields. This thesis aims to lower the barrier of origami tessellation pattern design by leveraging shape grammar principles. Shape grammar provides a systematic framework for generating and analyzing folding patterns, offering a more intuitive and structured approach to design. Through computational exploration and experimentation, this research demonstrates the efficacy of shape grammar in creating diverse and innovative origami tessellation patterns. By streamlining the design process, this approach not only enhances the experience for origami enthusiasts but also opens up new avenues for engineering and architecture applications, including deployable structures, flexible materials, and adaptive systems. The integration of shape grammar into origami tessellation design has the potential to catalyze advancements in both artistic expression and practical utility, fostering creativity and innovation in diverse fields. Key words: computational origami design, origami tessellation, shape grammar

Wrought iron seattice bridge

Fri, 01 Jan 1875 00:00:00 GMT

Wrought iron seattice bridge Church, Christopher A. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1875

Lattice girder bridge

Fri, 01 Jan 1875 00:00:00 GMT

Lattice girder bridge Burrison, Henry K. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1875

The infrared spectrum of solid methanol

Thu, 01 Jan 1948 00:00:00 GMT

The infrared spectrum of solid methanol Salter, Leonard P. (Leonard Paul) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1948; Includes bibliographical references (leaves 31-32).

The design of integrated distributed amplifiers

Tue, 01 Jan 1980 00:00:00 GMT

The design of integrated distributed amplifiers McHarg, Jeffrey Clay. Thesis: Elec. E., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1980; Bibliography: leaf 96.

Working of two classes of silver lead ore from the Merrimac Mining Co's Code at Newbury, Mass.

Sat, 01 Jan 1876 00:00:00 GMT

Working of two classes of silver lead ore from the Merrimac Mining Co's Code at Newbury, Mass. Townsend, Walter Davis, 1856-1918. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1876

The Richmond charcoal iron furnace

Sat, 01 Jan 1876 00:00:00 GMT

The Richmond charcoal iron furnace Robinson, Thos. W. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1876

Metallurgical treatment of air argentiferous galewa from Burleigh Tunnel, Colorado

Sat, 01 Jan 1876 00:00:00 GMT

Metallurgical treatment of air argentiferous galewa from Burleigh Tunnel, Colorado James, Samuel. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1876

An article on salt

Fri, 01 Jan 1875 00:00:00 GMT

An article on salt Burnet, Moses D. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1875

Report on the dressing and metallurgical treatment of an argentiferous lead ore from Georgetown, Colorado as performed at the Mining Laboratory of the M. I. T.

Thu, 01 Jan 1874 00:00:00 GMT

Report on the dressing and metallurgical treatment of an argentiferous lead ore from Georgetown, Colorado as performed at the Mining Laboratory of the M. I. T. Jackson, F. H. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1874

Paper mills and machinery

Sat, 01 Jan 1876 00:00:00 GMT

Paper mills and machinery Hollingsworth, S. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1876

Essex Company's Dam, acrop the Merrimac River at Lawrence

Fri, 01 Jan 1875 00:00:00 GMT

Essex Company's Dam, acrop the Merrimac River at Lawrence Sargent, W. F. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1875

Review of the Fall River Water Works

Fri, 01 Jan 1875 00:00:00 GMT

Review of the Fall River Water Works Allen, Samuel E. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1875

Holyoke Dam

Fri, 01 Jan 1875 00:00:00 GMT

Holyoke Dam Huntington, W. F. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1875

Brookline Water Works

Fri, 01 Jan 1875 00:00:00 GMT

Brookline Water Works Handy, Edward A. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1875

Tunnelling

Fri, 01 Jan 1875 00:00:00 GMT

Tunnelling Hammatt, Edw. A. W. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1875

A wrought iron bowstring girder

Fri, 01 Jan 1875 00:00:00 GMT

A wrought iron bowstring girder Dorr, E. S. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1875

The Salem Water Works

Fri, 01 Jan 1875 00:00:00 GMT

The Salem Water Works Dodge, Frank S. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1875

The practical estimation of the value of fanning materials with points on fanning

Sat, 01 Jan 1876 00:00:00 GMT

The practical estimation of the value of fanning materials with points on fanning Nickerson, Wm. E. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1876

An investigation of the action of chloride of sulphur upon spirits of turpentine

Sat, 01 Jan 1876 00:00:00 GMT

An investigation of the action of chloride of sulphur upon spirits of turpentine Waite, Charles N.; Low, Albert Howard, 1855-1936. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1876

Determination of oxygen in organic bodies

Sat, 01 Jan 1876 00:00:00 GMT

Determination of oxygen in organic bodies Fish, Chas. C. R. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1876

An economic study of the A. B. C. Traction Company

Tue, 01 Jan 1924 00:00:00 GMT

An economic study of the A. B. C. Traction Company Bain, L. D.; Estill, Harry, F. 1861-1942. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1924

A measure of the period and amplitude of the variations of AD Canis Minoris

Sun, 01 Jan 1984 00:00:00 GMT

A measure of the period and amplitude of the variations of AD Canis Minoris Martin, David W. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1984; Includes bibliographical references.

A microprocessor driven liquid crystal graphics display for aircraft use

Sun, 01 Jan 1984 00:00:00 GMT

A microprocessor driven liquid crystal graphics display for aircraft use Marzke, Lee Howard. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1984; Bibliography: leaf 35.

The use of transpiration in a precision temperature-controlled enclosure

Sun, 01 Jan 1984 00:00:00 GMT

The use of transpiration in a precision temperature-controlled enclosure Mastanduno, Richard Thomas. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1984; Bibliography: leaf 30.

Non-destructive evaluation of resistance seam welds by acoustic emission

Sun, 01 Jan 1984 00:00:00 GMT

Non-destructive evaluation of resistance seam welds by acoustic emission Markey, Karl R. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1984; Bibliography: leaf 45.

Comparison of techniques to measure the low wavenumber wall pressure spectrum of a turbulent boundary layer

Sun, 01 Jan 1984 00:00:00 GMT

Comparison of techniques to measure the low wavenumber wall pressure spectrum of a turbulent boundary layer Martini, Kyle F. Thesis: Mech. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1984; Includes bibliographical references.

Action of tungstic acid upon gelatin

Sat, 01 Jan 1876 00:00:00 GMT

Action of tungstic acid upon gelatin Atwood, Wm. P. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1876

Shafting and its fittings

Sat, 01 Jan 1876 00:00:00 GMT

Shafting and its fittings Lewis, Theo. J. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1876

Merrimac ore, burleigh tunnel ore

Fri, 01 Jan 1875 00:00:00 GMT

Merrimac ore, burleigh tunnel ore Shockley, W. H., 1855-1925.; Oxnard, Benjamin A. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1875

Design for a water works in a public park

Fri, 01 Jan 1875 00:00:00 GMT

Design for a water works in a public park Boyden, Amos J., 1853- Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1875

Report of a three weeks' experience in the Quarlz Mills at Grass Valley, Cal.

Mon, 01 Jan 1872 00:00:00 GMT

Report of a three weeks' experience in the Quarlz Mills at Grass Valley, Cal. Locke, Brad. H. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1872

Investigation of the stray power in Edison dynamos

Thu, 01 Jan 1891 00:00:00 GMT

Investigation of the stray power in Edison dynamos Garrison, Charles.; Greer, Medorem W. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1891

Design of a single track, iron, Warren Girder Rail Road Bridge

Thu, 01 Jan 1874 00:00:00 GMT

Design of a single track, iron, Warren Girder Rail Road Bridge Howard, C. P. (Charles P.) Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1874

A Murphy-Whipple Truss

Thu, 01 Jan 1874 00:00:00 GMT

A Murphy-Whipple Truss Sweetser, Arthur W. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1874

Description of a design for a single track railroad bridge of 190 feet span

Thu, 01 Jan 1874 00:00:00 GMT

Description of a design for a single track railroad bridge of 190 feet span Shaw, Edward S. (Edward Stone) Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1874

Designs and estimates of a Murphy-Whipple Truss

Thu, 01 Jan 1874 00:00:00 GMT

Designs and estimates of a Murphy-Whipple Truss Perkins, H. B. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1874

The Linville Bridge

Thu, 01 Jan 1874 00:00:00 GMT

The Linville Bridge Emerson, J. S. (Joseph S.) Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1874

Linville Truss

Thu, 01 Jan 1874 00:00:00 GMT

Linville Truss Holbrook, E. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1874

A double Warren girder

Thu, 01 Jan 1874 00:00:00 GMT

A double Warren girder Doane, G. E. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1874

Design for a post truss bridge

Thu, 01 Jan 1874 00:00:00 GMT

Design for a post truss bridge Blunt, William T. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1874

The post iron truss bridge

Thu, 01 Jan 1874 00:00:00 GMT

The post iron truss bridge Barrows, Herbert. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1874

Calculations for the platform of a suspension bridge with special reference to the cross girders

Sun, 01 Jan 1871 00:00:00 GMT

Calculations for the platform of a suspension bridge with special reference to the cross girders Howland, A. H. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1871

Design for a bowstring bridge

Mon, 01 Jan 1872 00:00:00 GMT

Design for a bowstring bridge Dodge, William Baldwin. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1872

A report upon a Howe truss

Mon, 01 Jan 1872 00:00:00 GMT

A report upon a Howe truss Shepard, W. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1872

Design for wrought iron railway bridge

Mon, 01 Jan 1872 00:00:00 GMT

Design for wrought iron railway bridge Allen, C. Frank (Calvin Frank), 1851-1948. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1872

On the composition of the acid oxalates of potassium, ammonium and sodium

Fri, 01 Jan 1869 00:00:00 GMT

On the composition of the acid oxalates of potassium, ammonium and sodium Nichols, Wm. Ripley (William Ripley), 1847-1886. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1869

A user-friendly interface for a poisson-solver

Thu, 01 Jan 1987 00:00:00 GMT

A user-friendly interface for a poisson-solver Johnson, Ted C. (Ted Christian) Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1987; Bibliography: leaf 98.

Modeling Hydrogen Transport in BABY

Wed, 01 May 2024 00:00:00 GMT

Modeling Hydrogen Transport in BABY Weaver, Colin Fusion energy stands as a beacon of hope in the realm of sustainable power generation, offering the potential to meet global energy demands without adverse environmental impacts. However, fusion power is not yet commercially viable, and significant research is still needed to develop the technologies necessary to make it a reality. Central to the realization of practical fusion reactors is the efficient management of tritium, a scarce and radioactive isotope that serves as the fuel in a deuterium-tritium fusion reaction. The liquid immersion blanket concept, pioneered by endeavors like Commonwealth Fusion Systems, represents a significant stride towards addressing the challenges of tritium breeding and extraction. At the forefront of this endeavor lies the LIBRA Experiment, the goal of which is to better understand tritium breeding, containment, and extraction under a fusion-like neutron spectra, and BABY, a scaled-down iteration of the LIBRA Experiment designed to serve as a stepping stone to the full LIBRA Experiment. BABY serves as a testbed for evaluating Tritium extraction mechanisms and assessing the feasibility of achieving self-sufficiency in fuel production within a fusion power plant environment. In this context, understanding hydrogen transport phenomena within the BABY system emerges as a crucial aspect of optimizing tritium extraction and ensuring tritium self-sufficiency. By employing advanced modeling techniques simulating fluid flow and heat transfer to inform tritium transport simulations in FESTIM, this thesis endeavors to elucidate the intricacies of hydrogen migration mechanisms, diffusion rates, and their impact on tritium dynamics within the molten salt environment of BABY. Steady state simulations of bulk tritium transport coefficients provide results for the range of tritium transport coefficients for BABY, while transient simulations provide insight into the complex dynamics surrounding tritium transport through the various surfaces of BABY. The findings of this study hold profound implications for the fusion energy landscape, offering valuable insights that can inform the design and operation of future fusion reactors utilizing liquid immersion blankets. By elucidating the factors governing hydrogen transport in BABY, this research aims to contribute to the overarching goal of achieving sustainable and efficient fusion energy production.

Elastically Housed Kinematic Couplings for InterchangeableElectric Vehicle Batteries

Wed, 01 May 2024 00:00:00 GMT

Elastically Housed Kinematic Couplings for InterchangeableElectric Vehicle Batteries Sams, Sarah A. Commercial adoption of electric vehicle technologies has lagged due to immense charging downtime, but kinematic couplings have the potential to bridge this barrier by allowing for battery swaps and simultaneous operation and back-up battery charging. Designing parameters such as an elastic housing to damp the battery’s connection could overcome challenges with regard to manufacturing tolerance and operational loads. Accounting for proper preload and compliance for disturbance rejection is critical to maintain sufficient electrical contact while avoiding arcing. Kinematic couplings can provide enough contact area through Hertz line contact for a low resistance electrical contact, and Hertz stresses under loads are reasonable for conductive materials to bear without yield for long life cycles. This paper explored kinematic couplings as electrical conductors for electric vehicles by modifying a 2002 GEM E825. Kinematic coupling modifications decrease charging downtime by 98.33%. Elastic housings for ball-socket Kinematic couplings are predicted to increase the hertz contact area by 2684%, while decreasing the stress factor by 98.9% from a typical ball-groove kinematic coupling of the same size, allowing for larger vehicle batteries operated under higher forces and currents. Elastically housed kinematic couplings are a promising design pathway towards interchangeable electric vehicle batteries.

Design and Characterization of a Wave Energy Converter Array Experimental Test Platform

Wed, 01 May 2024 00:00:00 GMT

Design and Characterization of a Wave Energy Converter Array Experimental Test Platform Herrero-Marques, Penelope Wave energy is a promising source of renewable energy that has the potential to play a significant role in the global transition towards sustainable energy. Unlike other forms of renewable energy, wave energy is not dependent on weather patterns or daylight hours, making it a reliable and consistent source of energy. As the demand for clean energy continues to grow, wave energy can provide a valuable contribution to the global energy mix, helping to reduce greenhouse gas emissions and mitigate the negative impacts of climate change. Wave energy is harvested by wave energy converters—devices that convert the kinetic energy of ocean waves into electrical energy. Wave energy converter (WEC) arrays consist of multiple individual WEC devices that are arranged in a specific pattern. The arrangement of the devices within the array is designed to optimize their performance and reduce their negative effects on the surrounding environment. Developing reliable models of WEC array performance and optimal array configurations is critical to advancing research in this exciting field. This thesis details the design and validation of a test rig for experimentally testing wave energy converter array performance in the MIT Building 48 tow tank. The test rig features a novel magnetic damper that was designed and characterized to uniquely suit the conditions of the tow tank. The final test rig is capable of measuring the power captured by oscillating buoys as a function buoy shape, mass, and damping provided. Beyond facilitating hydrodynamics research, the test platform will be a valuable educational resource for classes such as Hydrodynamics that incorporate laboratory components. Its functionality will allow students to explore firsthand the principles of wave energy conversion, buoy dynamics, and the impact of various design parameters on energy capture. By providing hands-on experience, the test rig will enhance learning outcomes and cultivate a deeper understanding of renewable ocean energy technologies.Wave energy is a promising source of renewable energy that has the potential to play a significant role in the global transition towards sustainable energy. Unlike other forms of renewable energy, wave energy is not dependent on weather patterns or daylight hours, making it a reliable and consistent source of energy. As the demand for clean energy continues to grow, wave energy can provide a valuable contribution to the global energy mix, helping to reduce greenhouse gas emissions and mitigate the negative impacts of climate change. Wave energy is harvested by wave energy converters—devices that convert the kinetic energy of ocean waves into electrical energy. Wave energy converter (WEC) arrays consist of multiple individual WEC devices that are arranged in a specific pattern. The arrangement of the devices within the array is designed to optimize their performance and reduce their negative effects on the surrounding environment. Developing reliable models of WEC array performance and optimal array configurations is critical to advancing research in this exciting field. This thesis details the design and validation of a test rig for experimentally testing wave energy converter array performance in the MIT Building 48 tow tank. The test rig features a novel magnetic damper that was designed and characterized to uniquely suit the conditions of the tow tank. The final test rig is capable of measuring the power captured by oscillating buoys as a function buoy shape, mass, and damping provided. Beyond facilitating hydrodynamics research, the test platform will be a valuable educational resource for classes such as Hydrodynamics that incorporate laboratory components. Its functionality will allow students to explore firsthand the principles of wave energy conversion, buoy dynamics, and the impact of various design parameters on energy capture. By providing hands-on experience, the test rig will enhance learning outcomes and cultivate a deeper understanding of renewable ocean energy technologies.

A Framework for Analysis of Softball Pitching, as Applied to Legal and Illegal Pitches

Wed, 01 May 2024 00:00:00 GMT

A Framework for Analysis of Softball Pitching, as Applied to Legal and Illegal Pitches Pendowski, Katia D. In response to the NCAA’s 2023 rule change allowing softball pitchers to legally disengage from the playing surface while delivering a pitch, this study develops a framework to analyze and compare the legal drag, legal leap, and illegal replant pitching techniques. By developing a pose estimation algorithm and Recurrent Neural Network (RNN) for use on videos of real collegiate pitchers, we aim to distinguish physiological differences between these types of pitches and use our RNN to automatically detect illegal pitches. Our pose estimation results demonstrate the algorithm's effectiveness in extracting patterns from pitching videos. Key features such as the distance between the pitcher’s right knee and right toe, as well as the right toe x-position vs. time, emerge as crucial indicators for distinguishing legal and illegal pitches. The RNN achieved an accuracy of 71.4%, with a loss rate of 0.875. This framework offers a data-driven approach to softball pitching mechanics, providing valuable insights for researchers and coaches alike.

Analysis of Origami Flasher-Inspired Deployable Structures Through Dynamic and Experimental Modeling

Wed, 01 May 2024 00:00:00 GMT

Analysis of Origami Flasher-Inspired Deployable Structures Through Dynamic and Experimental Modeling Bai, Jane The Origami “flasher” model holds immense engineering promise due to its ability to alternate between a compressed 3-dimensional form and a deployed 2-dimensional form. While zero-thickness mathematical models have been thoroughly covered, dynamic modeling and material exploration are essential for the successful design of finite-thickness models. In this research, the mathematical effects of parameters such as center polygon size, unit panel length, and crease arrangement on flasher surface area optimization are first established. Software is then used to create a dynamic model that combines kinematic analysis with material properties to visualize the folding geometry and internal strain of the flasher pattern and to identify points of analysis for the experimental model. Finally, a stored-energy-based deployable experimental model is made using Yupo paper and video analysis done to understand damping behavior, deployment trajectory, and torque distribution. A discussion on design considerations for flasher patterns follows and potential topics for future research are set forth.

Optimization of Fasp for Li-Ion Cathode Material Production

Wed, 01 May 2024 00:00:00 GMT

Optimization of Fasp for Li-Ion Cathode Material Production Hickey, Connor The need to improve battery technology is higher than ever given the projected increase in battery consumption in the next decade and beyond. One key limiting factor of batteries is their cost, and one major way to reduce battery costs is by decreasing the time needed to produce them. The FASP system uses Flame-Assisted Spray Pyrolysis, and the principles of combustion to speed the process of creating the materials for lithium-ion cathodes, more specifically the NCM-811 variation of the lithium-ion batteries. This study aims to identify key factors in improving the powder production of the FASP system. One way it aims to do this is by creating a CFD simulation, within ANSYS, to create an accurate picture of the behaviour of the fluids within the pipe flow. Another way it aims to optimize FASP is by conducting various experiments to test the simulations and try to find areas of disagreement to find a direction to improve the CFD model. The final way this paper aims to optimize FASP is by conducting several powder-producing experiments and testing various variables to find the best combination.

A Wearable Device to Inform Pressure Injury Prevention Support Surfaces Selection and Design

Wed, 01 May 2024 00:00:00 GMT

A Wearable Device to Inform Pressure Injury Prevention Support Surfaces Selection and Design Sapozhnikov, Katherina Pressure injuries are a preventable but persistent medical challenge, with 2.5 million Americans developing pressure injuries each year. Pressure injuries are uniquely challenging to manage for wheelchair users, who have to sit for extended periods of time, up to 10-12 hours per day. Measuring the interface pressure between support surfaces and the body can assist in selecting surfaces that minimize the pressure to prevent pressure injuries from developing. However, pressure mapping systems are expensive and inaccessible for personal use outside of rehabilitation centers and hospitals. A prototype was developed to measure the interface pressure and movements of the user, using force sensing resistors and accelerometer data. Through this system, the interface pressure across surfaces can be compared to select appropriate sitting surfaces, inform repositioning habits, and prevent pressure injury development.

Pressure Swing Assisted Desorption for Atmospheric Water Collection

Wed, 01 May 2024 00:00:00 GMT

Pressure Swing Assisted Desorption for Atmospheric Water Collection Kim, Haeri Ensuring water equity is an urgent and challenging issue in the light of climate change, global conflict, and socioeconomic disparities. Atmospheric water harvesting provides a promising option to collect water from the air, even in considerably dry conditions (RH < 40%), expanding the reach of this application to areas that would be particularly prone to clean water scarcity. The MIT Device Research Lab is developing a device for such applications that would be capable of producing drinkable water in even extremely dry environments. Current methods of atmospheric water harvesting focus on thermal desorption, where heat is applied to release the water vapor from the sorbent. Another method worth exploring is utilizing pressure swings to release this water vapor, and seeing how a combined method of thermal and depressurized desorption would affect the efficiency of this device. An initial MATLAB model showed that the methods, in order of slowest to fastest, should be (1) solely pressure swing desorption, (2) solely temperature swing desorption, and (3) the combined method using simultaneous pressure and temperature swings. The results from the experiment using the MOF UiO-66 as the sorbent showed that the combined procedure would indeed be the fastest, potentially twice as fast as a purely thermal desorption method and five times faster than a purely depressurized desorption method. The next step following this project would be the assembly of a vacuum-grade enclosure in which a small scale test unit of the device the MIT DRL is developing. A detailed design and brief procedure is included in the final section of this thesis.

A Data-Driven Analysis to Determine the Electrical Needs of a Hybrid Powertrain System for Small, Hyper-Optimized, Track-Day Vehicles

Wed, 01 May 2024 00:00:00 GMT

A Data-Driven Analysis to Determine the Electrical Needs of a Hybrid Powertrain System for Small, Hyper-Optimized, Track-Day Vehicles Asa, Henry J. In an effort to maximize the performance of RUSH Auto Work’s RUSH SR racecar, a hybrid powertrain system was designed and evaluated to estimate the performance gains from imple- menting such a system. An extensive Python program was developed to analyze real-world race data for the RUSH SR, determining energy losses while braking, the vehicle’s current acceleration capabilities, as well as the vehicle’s limitations. This ultimately quantified the vehicle’s current performance values/capabilities, and provided a strong foundation for the analyses that determined the anticipated implications of adding a hybrid powertrain system to the car. Despite the mass additions associated with adding an electric motor, battery pack, and additional components to control the system, the power gains from the system yielded a net greater power-to-weight ratio than the original vehicle without the hybrid sys- tem. An analysis of energy recuperation through regenerative braking demonstrated the potential to reduce the size of the battery pack (which decreases the mass of the system) without compromising on the power requirements and capabilities of the system. During periods of heavy braking, it was found that a significant portion of the battery could be recharged, allowing for significant reductions in the capacity of the battery pack.

Heart Rate and Neuromuscular Fatigue in Intermittent Sprinting

Wed, 01 May 2024 00:00:00 GMT

Heart Rate and Neuromuscular Fatigue in Intermittent Sprinting Cooksey, Paige E. Monitoring and regulating fatigue are essential tasks for the general well-being and success of competitive athletes. Many wearable fitness devices measure how strenuous workouts are based on time spent in each heart rate zone which represents cardiovascular difficulty. Despite having new adaptations for weight training, these devices do not have a way to quantify the fatigue of less aerobic, yet very strenuous workouts like sprinting. This paper investigates various heart rate metrics, including rate of heart rate increase/decrease, integrated heart rate, and one-minute heart rate recovery, of two well-trained subjects across a sprint-interval workout (2x50-meters, 3x100-meters, 2x50-meters) to determine if they are correlated with neuromuscular fatigue as quantified by the percent reduction in countermovement jump height after each repetition. Out of four workout trials, only one showed a significant relationship between the metrics, which were consistent across workouts for each subject, and fatigue, indicating that the analyzed metrics may not be a sound way to monitor fatigue in athletes. However, it is also possible that more subjects performing more trials of the workout could reveal additional relationships. A further study would be to perform a uniform sprint workout since a significant relationship did exist for one of the subjects across the sprint intervals of the same length (100-meters), indicating that such a workout may yield different results, but, once again, further data collection would be needed to draw conclusive statements. Regardless, other metrics such as muscle activity, velocity, acceleration, oxygen uptake, etc. should be considered for future research into quantifying neuromuscular fatigue in sprinting.

Development of a Millimeter-Scale Laminar Flow Mixer for Rapid Iteration of Sustainable Energy Materials

Wed, 01 May 2024 00:00:00 GMT

Development of a Millimeter-Scale Laminar Flow Mixer for Rapid Iteration of Sustainable Energy Materials Maredia, Sharil Material discovery for sustainable energy materials has historically been rate-limited by low-throughput synthesis and characterization methods. However, using automation, these rate-limiting steps can be improved. The accelerated development of sustainable materials necessitates the creation of a high-throughput synthesis and assembly system, capable of rapidly iterating and characterizing proposed designs. Archerfish, the current tool used for multi-material deposition, is a strong first step in this direction, automatically generating compositional gradients of up to two material precursors. However, Archerfish has room for improvement: the device is only capable of handling at most two input precursors and is imprecise due to poor compositional control and mixing. As such, there is a need for an improved junction apparatus that can handle substantially more precursors and ensure mixing while retaining compositional control. Additional challenges associated with this device include the need to be chemically resistant, have millimeter-scale channels, and mix fluids that are initially joined in the laminar flow regime. The proposed design introduces flow obstacles akin to a magician’s sword box and is validated using CFD simulations and mixing experiments.

Cylinder Casting of the Atlantic “Make- and-Break” Marine Engine

Wed, 01 May 2024 00:00:00 GMT

Cylinder Casting of the Atlantic “Make- and-Break” Marine Engine Mosser, Mark The Atlantic “Make-and-Break” Marine Engine was one of the first engines to be mass produced on the Canadian Atlantic coast, and it quickly revolutionized the fishing industry in that area. The Apprentices of Pappalardo lab began a project to make a replica of one of these engines in 2016 to so that they could gain a deeper understanding of sandcasting and how this engine was fabricated. This thesis is a continuation of that project. Students have been fabricating parts for the engine since 2016, and as of Fall 2024 there was one part left to cast: the cylinder. This thesis covers 3 attempts at casting the cylinder for this engine. I will explain the previous work done to cast this part and what I modified from the previous work to make the part easier to cast. I will explain the failure modes that I experienced from the pours, the ways they can be mitigated in the future, and lessons learned for future attempts to cast this cylinder.

Design of a Testing Fixture for the Characterization and Modeling of a Powered Prosthetic Ankle Using a Lorentz Force Actuator

Wed, 01 May 2024 00:00:00 GMT

Design of a Testing Fixture for the Characterization and Modeling of a Powered Prosthetic Ankle Using a Lorentz Force Actuator Hamed, Yasin Developments in prosthetic ankles have been improving amputee gaits, gradually approaching a more normal, non-amputee gait as designs develop. Currently, powered ankle prosthetics, or bionic ankles, hold the potential to mold the amputee gait much closer to its biological counterpart. This requires accurate control of the prosthesis and thus requires an accurate understanding of the plant model characterizing the bionic ankle. It is typically rather difficult to analytically develop such a model, so this project explores an experimental approach through the use of nonlinear stochastic system identification techniques to characterize the prosthetic. Results from initial experiments which use the method for characterizing known linear models revealed unaccounted for sources of error and nonlinearity which future work will attempt to remedy to continue developing such a characterization fixture.

Design and Fabrication of an Oscillating Tool for Powder Spreading in Metal Additive Manufacturing

Wed, 01 May 2024 00:00:00 GMT

Design and Fabrication of an Oscillating Tool for Powder Spreading in Metal Additive Manufacturing Boronkay, Cadence W. Powder spreading methods for metal additive manufacturing processes, such as laser powder bed fusion and binder jetting, are intended to produce thin, dense, and uniform powder layers in order for finished parts to have satisfactory material and mechanical properties. The spreading of fine powders is particularly challenging due to their cohesive nature. Previous computational simulations have been performed and show that using a linearly oscillating spreading tool can have favorable results on layer quality. This thesis focuses on the design and implementation of an oscillating spreading tool on a pre-existing testbed. The system dynamics of an object oscillating at an amplitude of 40 microns at frequencies in the range of 9.55 - 955 Hz are modeled and analyzed. Two designs are developed for the mechanism, powered by either a piezoelectric stack or a voice coil linear motor. The machining of parts was qualified for runout and straightness, and the assembly of the piezo mechanism was built onto the testbed. Work remains to complete the system implementation and to test the motion and simulation results. Continued improvements and further work are suggested.

Mechanical characterization of BAAM extruded rPET: impact of screw speed and methods for measuring Young’s modulus

Wed, 01 May 2024 00:00:00 GMT

Mechanical characterization of BAAM extruded rPET: impact of screw speed and methods for measuring Young’s modulus Su, Ashley The issue of plastic waste and recycling has reached critical proportions in recent years, exacerbated by the rapid growth in plastic production and consumption. Polyethylene terephthalate (PET), a commonly used plastic, presents particular challenges due to its widespread application in various industries, ranging from food and liquid packaging to electronics and automotive parts. Despite its versatility, PET's non-biodegradable nature contributes significantly to environmental pollution, with a substantial portion ending up in landfills or the natural environment. Current recycling methods, while essential, face limitations in effectively managing PET waste, with only a fraction of it actually being recycled. As a result, there is an urgent need for innovative recycling techniques and sustainable solutions to address the escalating problem of PET waste and its environmental impact. This paper investigates the mechanical properties of recycled polyethylene terephthalate (rPET) samples extruded using the Big Area Additive Manufacturing (BAAM) system at two different screw speeds: 90 and 115 rpm. Two distinct test methods, a simplified three-point bending test and uniaxial tensile test, were utilized to determine the Young’s modulus of the samples. The results indicate that the Young’s modulus of the samples extruded at 90 rpm was consistently greater than those extruded at 115 rpm for both test methods. This suggests that screw speed, as a parameter in the extrusion process, influences the mechanical properties of rPET. Additionally, the study highlights the need for further investigation into the interchangeability of the two test methods. Future research recommendations include exploring methods to encourage consistency in extrusion, such as utilizing moisture analyzers, and investigating the mechanical behavior of rPET when blended with contaminants.

Control of Mecanum Wheels in Arbitrary Position, Angle and Number for Complete Omni-Directional Motion

Wed, 01 May 2024 00:00:00 GMT

Control of Mecanum Wheels in Arbitrary Position, Angle and Number for Complete Omni-Directional Motion Morin, James D. Mecanum wheels are often used in vehicle/robotics applications where agility is a top priority, since they can be used to translate the vehicle in any direction on the ground as well as rotate around any center point. However, the standard placement and orientation of these wheels is quite rigidly adhered to in common practice, causing little to no flexibility and variation in this aspect of the vehicle's design. This thesis shows how the use of mecanum wheels need not fall under such constraints that are currently so widespread. Design considerations for arbitrary arrangements of mecanum wheels are presented, as well as some motivations for deviating from standard configurations. A system for controlling a vehicle with an unconventional arrangement of mecanum wheels is developed, proving that the wheel's rotational axes and relative placement need not align in any specific way. Furthermore, equations are derived and presented that permit for the control of any number of mecanum wheels in any arbitrary configuration on the vehicle. This control is possible for the user simply by measuring a few key details about the vehicle's wheels: for each wheel, the location of the wheel in the vehicle's coordinate frame, the positive-signal direction of the motors, and the angle of the wheel's diagonal rollers. To prove the results, a random arrangement of wheels is generated and assembled on a robot, which is successfully controlled using the framework described in this thesis. Also, an example is given of a robot which uses the methodology described to compete very successfully in an MIT robotics class competition.

Experimental Validation of Indirect Liquid Cooling Computational Thermal Modeling

Wed, 01 May 2024 00:00:00 GMT

Experimental Validation of Indirect Liquid Cooling Computational Thermal Modeling Alvarez, Isabel K. Indirect dry-interface liquid cooling for electronics offers a modular and lightweight approach to thermal management. As part of development for the Navy’s integrated Power and Energy Corridor (NiPEC), multiple computational thermal analyses of this cooling method have been conducted but not yet tested against experimental results. NiPEC involves the deployment of converter units referred to as integrated Power Electronics Building Blocks (iPEBBs), which experience heat generation from four rows of MOSFET switches and a transformer. The goal of thermal simulations is to predict the liquid flow rate through a cold plate given a heat flux which will keep the iPEBBs below 100◦C. Experimental data on indirect liquid cooling of a layered substrate was collected with varied power, temperatures and flow rates. The data was verified through a STAR-CCM+ CFD simulation by David Hernandez, then used as a training and test set for a physics-informed neural net- work (PINN) model by Aniruddha Bora. The PINNs simulations were shown to improve in consistency and accuracy when trained on data gathered in the experimental trials. The collected experimental data set is available to the public for training and testing computational models.

Experimental Determination of an AUV's Drag Resistance in a Towing Tank

Wed, 01 May 2024 00:00:00 GMT

Experimental Determination of an AUV's Drag Resistance in a Towing Tank Hart-Kennedy, Leighton The market for AUVs has expanded dramatically over the past several decades, a trend that is expected to continue over the next 10 years. AUVs operate autonomously using a dynamic controller that accounts for the dynamics of the system, including the drag resistance of the AUV. This paper examines the method of using a calm-water resistance test in a towing tank to determine the resistance of an AUV. A scale model of a survey class AUV was created using a 3d printer and mounted in a towing tank. The model was towed, and the resistance force recorded for a range from 0.3 to 0.9 m/s. An estimation of the AUV’s resistance was determined using this data. The average drag coefficient was calculated at each speed using this data. The average drag coefficient was fit to a linear curve with the logarithm of the Reynolds number of the form Cd = a∗log₁₀(Re) + b where a = −0.0771 ± 0.0507 and b = 0.484 ± 0.277.

Vibrational Control of a Cantilever Beam Using Sensor and Actuator Averaging Methods

Wed, 01 May 2024 00:00:00 GMT

Vibrational Control of a Cantilever Beam Using Sensor and Actuator Averaging Methods Rodriguez, Andre In this paper, governing equations for cantilever beams are derived. We go over sensor and actuator averaging, a method to create a spatial filter that is insensitive to model parameter uncertainty. We develop a controller to actively control cantilever beam vibration using accelerometer input. The controller is a classic single-sensor single-actuator system that achieves a phase margin of 31° and bandwidth of 3.5 kHz. We then use the same controller but implement a sensor averaging method to achieve a phase margin of 45° with the same bandwidth. Therefore, we increase our phase margin by almost 50% at almost no cost to the controls designer.

Impact of the Variable Weighted MOI Baseball Bat on Swing Velocity Enhancement

Wed, 01 May 2024 00:00:00 GMT

Impact of the Variable Weighted MOI Baseball Bat on Swing Velocity Enhancement Chapman, Luke A. The sport of baseball is ubiquitous in American culture and has observed global prominence. Since its creation in the 1800s, individuals have sought to improve batting performance which is evident by the plethora of scientific literature that exists on the topic through today. Bat velocity is one key aspect of a successful baseball swing because as bat velocity improves, key components such as decision time, swing mechanics and batted-ball velocity also improve. As such, a prototype bat design is proposed in this study through a brief validation protocol of identified literature that speaks to core physical principles (i.e. moment of inertia and center of mass) combined with market research validation. This prototype model is adjustable for different age groups to allow for development at a young age. Although this prototype requires further validation, the potential for superior batting performance is promising.

Design of a Testbed for Haptic Sensor Calibration and Characterization

Wed, 01 May 2024 00:00:00 GMT

Design of a Testbed for Haptic Sensor Calibration and Characterization Lee, Man Ching Cindy We present the design, fabrication, and application of a 6-axis test bed for the characterization and calibration of haptic force sensors. This test bed can apply and measure contact forces up to 10N anywhere within a 60x60x60mm volume, at angles up to ±10 degrees from the normal. A procedure for haptic sensor calibration and characterization was developed for this test bed. A visuotactile sensor designed by the Toyota Research Institute was used to demonstrate the application of the test bed, resulting in calibration curves for force measurements in all axes as well as the location of force in x and y. The test procedures also showed the presence of hysteresis in the haptic sensor’s normal force measurement, and a lack of hysteresis in the sensor’s shear force measurement.

Design of Floor Joists Manufactured via Large Scale Additive Manufacturing

Wed, 01 May 2024 00:00:00 GMT

Design of Floor Joists Manufactured via Large Scale Additive Manufacturing Godfrey, Tyler There are 1.6 billion people in the world that lack adequate housing. An enormous amount of plastic is produced in the world; most of it doesn’t get recycled. The MIT HAUS group is looking to solve both of those issues by 3D printing homes out of recycled plastic. The group has printed foundation components using thermoplastic composites. The HAUS group is working from the ground up, so following the foundation would be a floor. This thesis specifically looks at the design of floor joists, the beams under the floor supporting the floor. In trying to build homes for those that lack adequate shelter, the MIT HAUS group has to design to minimize cost. The design of the floor joists seeks to minimize cost by designing a thin joist. These thin designs minimize both weight and production time. The floor joists are trusses, with different designs varying different parameters, such as the number of triangles in the beam. The designs were put through FEA simulation and small scale testing to determine the best design. Lastly, full large scale trusses for the selected design were printed on a BAAM by Additive Engineering Solutions and tested under typical floor loading conditions. Both simulation and test were in good agreement and the mid-span deflection was found to be well within accepted building standards. Key Words: 3D Printing, Floor Joists, Truss, Recycled Plastic

Macroscale Design and Modeling of Multifluidic Cantilever Devices for Advanced Nanoscale 3D Printing Applications

Wed, 01 May 2024 00:00:00 GMT

Macroscale Design and Modeling of Multifluidic Cantilever Devices for Advanced Nanoscale 3D Printing Applications Ceco, Irma A reliably functioning nanoscale 3D printer would be revolutionary in the advancement of the field of bioprinting and nanoprinting technologies; it would have many broad ranging potential applications such as the creation of biocompatible medical devices, alleviation of disease/medical complications through human organ fabrication, optimization of semiconductor manufacturing processes, and many others. One of the current focuses of this research is addressing the technical challenges associated with the development of a nanofluidic device that is capable of producing precise multifluidic, multimaterial prints. Thus, the primary objective of this thesis project is to design, model, and fabricate macroscale models of three potential fluid switching mechanisms/devices that can be implemented onto the existing nanoscale 3D printer to accommodate the use of multiple materials in a desired print. The project will develop designs of different potential fluid switching mechanisms, model their performance and fabricate them for future experimentation, and attempt to determine a suitable scaling factor for transitioning the macroscale model to micro/nanoscale dimensions while ensuring that performance of the device remains replicable. Preliminary functional requirements of the device/mechanism include steady state fluid switching capabilities, compatibility with current AFM nanoscale 3D printer set up and printing fluids, and the ability to reliably create a seal and ensure minimal contamination between fluids while still achieving laminar output flow for printing.

Investigating Internal Biomechanics for Insights into Climbing Difficulty

Wed, 01 May 2024 00:00:00 GMT

Investigating Internal Biomechanics for Insights into Climbing Difficulty Smith, Malia C. This thesis presents an analysis of rock climbing biomechanics, with a focus on understanding how force distribution across the climber’s limbs impacts route difficulty. By applying a static equilibrium model to pose estimations found using machine learning techniques, we examine climber movements filmed in an indoor climbing gym. The two main objectives were to understand optimal body positioning to reduce the amount of force climbers must put out in their arms and to determine whether there was a correlation in the amount of arm force and the rated difficulty of the climbing route. The force distribution across a climber’s limbs for different center of mass positions was found, which can inform more optimal positioning, and there seems to be a trend that as the listed difficulty of a climb increases, so does the required arm force, but the increase is not statistically significant.

Agnostic Testing Kiosk for Remote Vitals Sensing

Wed, 01 May 2024 00:00:00 GMT

Agnostic Testing Kiosk for Remote Vitals Sensing McLaughlin, Randy M. The research group of Brian Anthony has several projects related to the remote sensing of vitals, designed for patients spanning from infants in neonatal intensive care units (NICU) to elderly confined to the home. Many of which utilize a similar collection of sensors designed to collect data without making physical contact with the patient. Despite similarities between the systems, each was developed independently of the other and are largely incompatible, making it difficult to collaborate by sharing sensors and code. An agnostic testing system was developed from Ivan Goryachev’s Kiosk for Non-Contact Vital Sign Detection to incorporate RGB camera, thermal camera, radar, and auxiliary sensors for the measuring of heart rate, respiratory rate, body temperature, blood oxygen saturation, motion performance, ambient temperature and relative humidity, and position, with options to add more sensors. This system will act as a plug-and-play prototyping system for current and future projects of any remote vitals sensing configuration.

CAD Automation and Workflow Development for Novel Obstructive Sleep Apnea Prosthesis

Wed, 01 May 2024 00:00:00 GMT

CAD Automation and Workflow Development for Novel Obstructive Sleep Apnea Prosthesis Wang, Jessica Obstructive sleep apnea (OSA) affects millions of people every year, but standard treatments such as CPAP machines and mandibular advancement devices are invasive, uncomfortable, and troublesome to use. Patients will sometimes refuse these treatments altogether due to the associated negative impact on their lives. For the past year, I have worked within MIT Catalyst’s OSA research group to fabricate custom-fit, suction-activated mouthguards as a more comfortable and less intrusive alternative for OSA treatment. The mouthguard prostheses are being tested in an MIT study, with preparation to be tested in a VA clinical trial, where scalability and precision of manufacturing are crucial to procure meaningful data. To address this need for scalability and precision, the thesis will investigate methods, implementation, and results of code I have developed to automate portions of the device’s 3D CAD protocol. The goal of such automation is primarily to decrease human error in key design steps such as defining mouthguard curvature, and secondarily to increase the repeatability and efficiency of repetitive steps such as combining mesh components. More broadly, the thesis will assess the potential for this CAD protocol to be modularized into manual, semi-automated, and fully automated segments, with scripts being run via the Fusion360 CAD interface.

Electrifying Boost: Design & Optimization of a Hybrid Powertrain for the Rush SR

Wed, 01 May 2024 00:00:00 GMT

Electrifying Boost: Design & Optimization of a Hybrid Powertrain for the Rush SR Altala, Anthony This thesis details the integration of a hybrid powertrain into the Rush SR, a compact, gasolinepowered race car, focusing on the incorporation of the ME1616 electric motor into the vehicle's drivetrain. The project aimed to develop a bolt-on hybrid kit that owners can independently purchase and install. Utilizing design criteria from Rush Auto Works and first-order calculations of anticipated performance gains, the selection of the electric motor was guided meticulously. Using Computer-Aided Design (CAD) software, the electric motor was integrated into the vehicle’s architecture, with a detailed model developed to ensure alignment with the existing structure. Finite Element Analysis (FEA) was employed to validate the design of critical components, confirming their ability to meet the rigorous demands of competitive racing. A comprehensive manufacturing plan and Bill of Materials (BOM) were established to facilitate the immediate steps for building and implementing the electric motor and power transmission systems. This project not only aims to enhance the performance of the Rush SR through hybrid technology but also serves as a practical demonstration of hybrid system integration in performance-focused, small-scale vehicles.

Manufacturing Strategies for NITE-processed SiC/SiC Ceramic Composite Components in the Liquid Sandwich Vacuum Vessel for Fusion Reactors

Wed, 01 May 2024 00:00:00 GMT

Manufacturing Strategies for NITE-processed SiC/SiC Ceramic Composite Components in the Liquid Sandwich Vacuum Vessel for Fusion Reactors Agarwal, Shreya In nuclear fusion tokamaks, vacuum vessels must be able to withstand large disruption forces resulting from potential plasma quenches. The Liquid Sandwich Vacuum Vessel (LSVV) is a novel alternative to conventional thick steel vacuum vessels. In the LSVV design, liquid lead circulates through channels within thin walls made of silicon carbide ceramic composite (SiC/SiC). By dissipating disruption forces within the liquid lead, the SiC/SiC walls can remain thin, improving heat transfer and the overall efficiency of the fusion reactor. However, SiC/SiC’s brittleness and anisotropy present challenges in machining and manufacturing. A literature review explores existing strategies for manufacturing, machining, and joining SiC/SiC components within the nuclear fusion context. A manufacturing plan is proposed for the fabrication and joining of tubular components and walled structures with integrated channels, aiming to further SiC/SiC manufacturing capabilities for the LSVV design. Further research is necessary to develop and validate robust manufacturing and joining methods specific to the LSVV application.

Experimental Strength Characterization of Epoxy Double Lap Joint for Carbon-Fiber Reinforced Polymer Tube

Wed, 01 May 2024 00:00:00 GMT

Experimental Strength Characterization of Epoxy Double Lap Joint for Carbon-Fiber Reinforced Polymer Tube Roach, Jonathan Sheehan Composite materials are increasingly affordable and utilized across many industries as they become better characterized and manufactured at high volumes to stock dimensions. One major challenge in their utilization is designing predictable structural joints. This report focuses on predicting the critical load of an epoxy adhesive double lap joint through experimentation. Test samples were designed and fabricated from off-the-shelf spindle-wound tubes and machined forged carbon fiber. An assembly of aluminum parts was designed and fabricated to hold the samples in an Instron universal testing machine for gathering of force-extension measurements as the joints were tested to failure. The stiffness of the off-the-shelf tubes was also experimentally determined to allow for the calculation of the theoretical critical load to fail the joint, according to a flat-plate joint theory. The collected data did not clearly support or contradict the applicability of the existing theory for double lap joints. While a few issues in the test setup limited the quantity and reliability of data, the process of designing the experimental hardware and procedure demonstrated the feasibility of this type of research and yielded valuable insights that can aid in the design of future experiments.

Our system of coal mining

Wed, 01 Jan 1868 00:00:00 GMT

Our system of coal mining Gilman, Charles C. Thesis: B.S., Massachusetts Institute of Technology, Department of Geology, 1868

Description of a geological section in Addison Co., Vermont

Wed, 01 Jan 1868 00:00:00 GMT

Description of a geological section in Addison Co., Vermont Tilden, Bryant P. (Bryant Parrot), 1817-1859. Thesis: B.S., Massachusetts Institute of Technology, Department of Geology, 1868

Report on Winamuck lead ore

Mon, 01 Jan 1872 00:00:00 GMT

Report on Winamuck lead ore Brewster, B. E. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1872

The process of puddling steel with the codorus ore

Sun, 01 Jan 1871 00:00:00 GMT

The process of puddling steel with the codorus ore Howe, Henry Marion, 1848-1922. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1871

The strains in bridges

Wed, 01 Jan 1873 00:00:00 GMT

The strains in bridges Felton, Samuel M. (Samuel Morse), 1853-1930. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1873

Derivation of formula for calculating the strains on the Howe truss bridge

Sun, 01 Jan 1871 00:00:00 GMT

Derivation of formula for calculating the strains on the Howe truss bridge Weeks, Isaiah S. P. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1871

Construction of a reservoir to supply the upper part of the town of Santa Cruz, California, with water

Sun, 01 Jan 1871 00:00:00 GMT

Construction of a reservoir to supply the upper part of the town of Santa Cruz, California, with water Cutler, Henry M. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1871

A treatise on two of the most popular of modern bridge trusses

Sun, 01 Jan 1871 00:00:00 GMT

A treatise on two of the most popular of modern bridge trusses Connor, A. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1871

The Hoosac Tunnel

Wed, 01 Jan 1868 00:00:00 GMT

The Hoosac Tunnel Stone, Joseph. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1868

Pile foundations

Wed, 01 Jan 1868 00:00:00 GMT

Pile foundations Hoyt, William E. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1868

The Bangor and Piscataquis Railroad

Wed, 01 Jan 1868 00:00:00 GMT

The Bangor and Piscataquis Railroad Greene, Charles E. (Charles Ezra), 1842-1903. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1868

Schweinfurt Green: some experiments on the action of arsenic trioxide on copper acetate, with the view of investigating the composition of the above compound

Sat, 01 Jan 1881 00:00:00 GMT

Schweinfurt Green: some experiments on the action of arsenic trioxide on copper acetate, with the view of investigating the composition of the above compound Hills, E. R. (Edgar R.), 1856- Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1881

A new volumetric assay for lead ores

Sat, 01 Jan 1870 00:00:00 GMT

A new volumetric assay for lead ores Hinman, C. W. (Chauncey Weed), 1873- Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1870

The Weston Smelting Company's Works, Blackhawk, Colorado

Sun, 01 Jan 1871 00:00:00 GMT

The Weston Smelting Company's Works, Blackhawk, Colorado Pratt, Geo. H. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1871

A method of determining experimentally the ratio of the intensity of wind-pressure on a surface inclined, to that one normal to the directions of the wind

Tue, 01 Jan 1895 00:00:00 GMT

A method of determining experimentally the ratio of the intensity of wind-pressure on a surface inclined, to that one normal to the directions of the wind Morey, Adrian, 1904-; Schmitz, Frank C. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1895

Combination rail-highway freight carrying units

Fri, 01 Jan 1943 00:00:00 GMT

Combination rail-highway freight carrying units Wells, Walter G. (Walter Goodwin) Thesis: B.S., Massachusetts Institute of Technology, Department of Civil and Sanitary Engineering, 1943; Includes bibliographical references (leaf 44).

The treatment of bleistein

Tue, 01 Jan 1884 00:00:00 GMT

The treatment of bleistein Doane, Alfred O. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1884

The smelting of native copper

Tue, 01 Jan 1884 00:00:00 GMT

The smelting of native copper Park, D. W. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1884

Description of the Calumet Mine

Wed, 01 Jan 1868 00:00:00 GMT

Description of the Calumet Mine Richards, Robert H. (Robert Hallowell), 1844-1945. Thesis: B.S., Massachusetts Institute of Technology, Department of Geology, 1868

The commercial efficiency of small electric motors

Thu, 01 Jan 1891 00:00:00 GMT

The commercial efficiency of small electric motors Capen, Barnard. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1891

Wrought iron girder bridge; for a double track, narrow gauge railway

Sat, 01 Jan 1870 00:00:00 GMT

Wrought iron girder bridge; for a double track, narrow gauge railway Turner, Edmund K. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1870

Design for an iron girder bridge

Sat, 01 Jan 1870 00:00:00 GMT

Design for an iron girder bridge Mason, Sampson D. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1870

The Canal Railroad Bridge across the Westfield River

Fri, 01 Jan 1869 00:00:00 GMT

The Canal Railroad Bridge across the Westfield River Carson, Howard A. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1869

Design for a plate girder bridge

Sun, 01 Jan 1871 00:00:00 GMT

Design for a plate girder bridge Pike, William A. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1871

Design for an iron girder bridge

Sun, 01 Jan 1871 00:00:00 GMT

Design for an iron girder bridge Fuller, Frank L. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1871

Specifications & calculations for an Howe truss bridge to cross the Housatonic River at South Lee, on the line of the Lee and West Stockbridge Rail Road

Sun, 01 Jan 1871 00:00:00 GMT

Specifications & calculations for an Howe truss bridge to cross the Housatonic River at South Lee, on the line of the Lee and West Stockbridge Rail Road Foote, Ed. H. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1871

Engineering notes upon Mississippi and Missouri River bridges

Wed, 01 Jan 1868 00:00:00 GMT

Engineering notes upon Mississippi and Missouri River bridges Firth, Frank R. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1868

Upon a kind of truss of built beam

Wed, 01 Jan 1868 00:00:00 GMT

Upon a kind of truss of built beam Smith, Charles A. (Charles Augustus), 1846-1884. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1868

The Brooklyn Water Works

Wed, 01 Jan 1868 00:00:00 GMT

The Brooklyn Water Works Sears, Walter H., 1847- Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1868

On the action of tri-iodide of phosphorus on iodide of ethyl

Mon, 01 Jan 1872 00:00:00 GMT

On the action of tri-iodide of phosphorus on iodide of ethyl Emmerton, F. A. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1872

Experiments upon the de composition of sulphide of arsenic by water

Mon, 01 Jan 1872 00:00:00 GMT

Experiments upon the de composition of sulphide of arsenic by water Swan, Clarence. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1872

Fermentation:- a few points of different theories briefly discussed

Sat, 01 Jan 1870 00:00:00 GMT

Fermentation:- a few points of different theories briefly discussed Merrill, Nathan Frederick, 1849- Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1870

Experiments upon the distribution of velocity in jets from standard orifices

Thu, 01 Jan 1891 00:00:00 GMT

Experiments upon the distribution of velocity in jets from standard orifices Knowles, Morris, 1869-1932.; Verges, Luis Francisco. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1891

A comparison of two lines for a railroad between Dedham and Walpole, Massachusetts

Thu, 01 Jan 1891 00:00:00 GMT

A comparison of two lines for a railroad between Dedham and Walpole, Massachusetts Collins, Reuben B. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1891

A study of the fungicidal action of ethylene oxide and carbon dioxide

Tue, 01 Jan 1935 00:00:00 GMT

A study of the fungicidal action of ethylene oxide and carbon dioxide Greenlie, David Graham. Thesis: B.S., Massachusetts Institute of Technology, Department of Industrial Biology, 1935; Includes bibliographical references (leaf 26).

Report on the Burleigh Tunnel, Georgetown, Col.

Sun, 01 Jan 1871 00:00:00 GMT

Report on the Burleigh Tunnel, Georgetown, Col. Lincoln, G. Russell. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1871

Geology of the Snake Mountain Region

Wed, 01 Jan 1868 00:00:00 GMT

Geology of the Snake Mountain Region Tolman, James P. Thesis: B.S., Massachusetts Institute of Technology, Department of Geology, 1868

The mechanism of galvanostatic voltage oscillations in formic acid

Wed, 01 Jan 1964 00:00:00 GMT

The mechanism of galvanostatic voltage oscillations in formic acid Matson, Wayne R. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1964; Includes bibliographical references (leaves 46-47).

The project of a concrete sea wall at Humarock Beach, Sea View, in the town of Scituate, Massachusetts

Fri, 01 Jan 1909 00:00:00 GMT

The project of a concrete sea wall at Humarock Beach, Sea View, in the town of Scituate, Massachusetts Shaw, Arthur L.; Wilson, Claude T. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1909

An acoustic study of the feature retroflex

Mon, 01 Jan 1990 00:00:00 GMT

An acoustic study of the feature retroflex Williams, Shawn Tiffany. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1990; Includes bibliographical references (leaf 39).

An investigation to detemine that grading of Scituate Gravel which will give the strongest concrete

Tue, 01 Jan 1918 00:00:00 GMT

An investigation to detemine that grading of Scituate Gravel which will give the strongest concrete Jones, William A.; Lacey, Henry R. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1918

The value of overseas study and engineering education projects

Sun, 01 Jan 1961 00:00:00 GMT

The value of overseas study and engineering education projects Bulkley, Jonathan W. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil and Sanitary Engineering, 1961; Includes bibliographical references (leaves 50-52).

Black and white referencing paths and the retinex theory of color vision.

Thu, 01 Jan 1976 00:00:00 GMT

Black and white referencing paths and the retinex theory of color vision. Stork, David Geoffrey. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1976; Bibliography: leaves [73-74].

Stewart's reduction works at Georgetown, Colorado ; Hill's smelting works at Black Hawk, Colorado

Sun, 01 Jan 1871 00:00:00 GMT

Stewart's reduction works at Georgetown, Colorado ; Hill's smelting works at Black Hawk, Colorado Whittier, Randal. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1871

Review of the Britannia Bridge

Sat, 01 Jan 1870 00:00:00 GMT

Review of the Britannia Bridge Curtis, Russell H. (Russell Hurd), 1850-1897. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1870

Design for Howes truss bridge

Sun, 01 Jan 1871 00:00:00 GMT

Design for Howes truss bridge Beal, Foster E. L. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1871

The extent of motion of the diaphragm of a telephonic receiver

Thu, 01 Jan 1891 00:00:00 GMT

The extent of motion of the diaphragm of a telephonic receiver Mansfield, Arthur N. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1891

A few instances, showing the possibility of applying the microscope to inorganic, qualitative analysis

Wed, 01 Jan 1873 00:00:00 GMT

A few instances, showing the possibility of applying the microscope to inorganic, qualitative analysis Very, Frank W. (Frank Washington), 1852-1927. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1873

On nitric acid and chlorate of potassium as an oxydizing mixture applicable to sulphur, sulphids, chromium, arsenic, organic matters, etc.

Fri, 01 Jan 1869 00:00:00 GMT

On nitric acid and chlorate of potassium as an oxydizing mixture applicable to sulphur, sulphids, chromium, arsenic, organic matters, etc. Storer, Frank H. (Frank Humphreys), 1832-1914. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1869

Jeweller's residues and lead smelting

Fri, 01 Jan 1886 00:00:00 GMT

Jeweller's residues and lead smelting Handy, James O. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1886

The experimental study of an alternating current dynamo by the air calorimeter method

Thu, 01 Jan 1891 00:00:00 GMT

The experimental study of an alternating current dynamo by the air calorimeter method Spaulding, H. P.; Wason, Leonard C. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1891

Contributions to the history of the compounds of oxalic acid

Fri, 01 Jan 1869 00:00:00 GMT

Contributions to the history of the compounds of oxalic acid Nichols, Wm. Ripley (William Ripley), 1847-1886. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1869

A study of the United States constant potential dynamo

Thu, 01 Jan 1891 00:00:00 GMT

A study of the United States constant potential dynamo Warner, George M.; Spooner, George H. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1891

Some tests on the Union Street Railroad, Dover, N.H.

Thu, 01 Jan 1891 00:00:00 GMT

Some tests on the Union Street Railroad, Dover, N.H. Dorr, Frank H.; England, Paul W. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1891

A treatise upon the Siemens Martin process of making steel upon the open hearth

Mon, 01 Jan 1872 00:00:00 GMT

A treatise upon the Siemens Martin process of making steel upon the open hearth Herrick, J. A. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1872

An experimental study of induction coils

Thu, 01 Jan 1891 00:00:00 GMT

An experimental study of induction coils Conant, Roger W.; Bradlee, Henry G. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1891

A determination of the discharge of the Connecticut River at South Deerfield, Mass.

Thu, 01 Jan 1891 00:00:00 GMT

A determination of the discharge of the Connecticut River at South Deerfield, Mass. March, Clement. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1891

A design for a sewerage system for a portion of the town of Walpole, Mass.

Thu, 01 Jan 1891 00:00:00 GMT

A design for a sewerage system for a portion of the town of Walpole, Mass. Moore, Fred F. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1891

Design for a turntable

Thu, 01 Jan 1891 00:00:00 GMT

Design for a turntable Keene, T. M. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1891

Design for a water supply, for the town of Walpole, Mass.

Thu, 01 Jan 1891 00:00:00 GMT

Design for a water supply, for the town of Walpole, Mass. Roberts, William J. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1891

Flow and yield of ground-water

Thu, 01 Jan 1891 00:00:00 GMT

Flow and yield of ground-water Daggett, H. C. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1891

A study of automatic train control

Tue, 01 Jan 1929 00:00:00 GMT

A study of automatic train control Holdrege, C. F.; House, H. E. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1929; Includes bibliographical references (leaf 153).

A plan of interlocking switches and signals at Ayer Junction, Mass.

Thu, 01 Jan 1891 00:00:00 GMT

A plan of interlocking switches and signals at Ayer Junction, Mass. Hammond, Charles F. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1891

A purchasing program for the M. I. T. fraternities

Wed, 01 Jan 1958 00:00:00 GMT

A purchasing program for the M. I. T. fraternities Jordan, Robert Elijah. Thesis: B.S., Massachusetts Institute of Technology, School of Industrial Management, 1958; Includes bibliographical references (leaf [95]).

Opera House for the city of Zürich, Switzerland

Sun, 01 Jan 1961 00:00:00 GMT

Opera House for the city of Zürich, Switzerland Lieb, Hans Peter. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1961; Includes bibliographical references (leaves 44-45).

Experimental investigation of vortex refrigeration

Wed, 01 Jan 1947 00:00:00 GMT

Experimental investigation of vortex refrigeration Corless, Robert J.; Solnick, Robert L. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1947; Bibliography: leaf 19.

Stair climbing wheelchair accessory device

Tue, 01 Jan 1991 00:00:00 GMT

Stair climbing wheelchair accessory device Chen, Elaine Yee Lan. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1991; Includes bibliographical references (leaf 81).

An analysis of global flow and algebraic factoring techniques in logic synthesis

Tue, 01 Jan 1991 00:00:00 GMT

An analysis of global flow and algebraic factoring techniques in logic synthesis Chen, Curtis S. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1991; Includes bibliographical references (leaves 32-33).

The development of testing methods for the evaluation of wrapping materials used for food packaging

Tue, 01 Jan 1935 00:00:00 GMT

The development of testing methods for the evaluation of wrapping materials used for food packaging Kohr, John M. Thesis: B.S., Massachusetts Institute of Technology, Department of Industrial Biology, 1935; Includes bibliographical references (leaf 54).

A study of the factors influencing alcohol production and yeast growth in beer wort

Tue, 01 Jan 1935 00:00:00 GMT

A study of the factors influencing alcohol production and yeast growth in beer wort Friedman, Isadore E. Thesis: B.S., Massachusetts Institute of Technology, Department of Industrial Biology, 1935; Includes bibliographical references (leaf 29).

A bacteriological study of dasheen fermentations

Tue, 01 Jan 1935 00:00:00 GMT

A bacteriological study of dasheen fermentations Comins, Saul. Thesis: B.S., Massachusetts Institute of Technology, Department of Industrial Biology, 1935; Includes bibliographical references (leaf 35).

A bacteriological study of quick-frozen lima beans

Tue, 01 Jan 1935 00:00:00 GMT

A bacteriological study of quick-frozen lima beans Bernhardt, H. E. Thesis: B.S., Massachusetts Institute of Technology, Department of Industrial Biology, 1935; Includes bibliographical references (leaf 21).

The effect of ultra-violet light on thermophilic bacteria in sugar

Tue, 01 Jan 1935 00:00:00 GMT

The effect of ultra-violet light on thermophilic bacteria in sugar Avery, Maurice E. Thesis: B.S., Massachusetts Institute of Technology, Department of Industrial Biology, 1935; Includes bibliographical references (leaf 51).

The bactericidal action of wood smoke

Tue, 01 Jan 1935 00:00:00 GMT

The bactericidal action of wood smoke O'Brien, Frederick F. Thesis: B.S., Massachusetts Institute of Technology, Department of Industrial Biology, 1935; Includes bibliographical references (leaf 29).

Little Saigons in the US: A story about community and adaptation from 1988 to 2024

Wed, 01 May 2024 00:00:00 GMT

Little Saigons in the US: A story about community and adaptation from 1988 to 2024 Phan, Angelica After the fall of Saigon in 1975, thousands of Vietnamese refugees fled to the US, initiating a significant wave of Vietnamese immigration. With assistance from resettlement agencies and sponsors, Vietnamese immigrants were resettled throughout the country. Despite this dispersion, many Vietnamese refugees clustered together and formed enclaves, which soon became known as Little Saigons. While the first Little Saigon was officially recognized in 1988, they began to take shape in the preceding decade. Since their development, Vietnamese enclaves have encountered various challenges, including the COVID-19 pandemic. However, Vietnamese Americans have been actively working to preserve their enclaves. Exploring Little Saigons across the West, Northeast, Midwest, and South reveals their profound historical and cultural significance. These enclaves provided Vietnamese refugees with economic stability and a sense of community reminiscent of their lost homeland. Moreover, they served as crucial links to Vietnamese culture, granting access to Vietnamese goods and services. Additionally, Little Saigons served as central gathering spaces for socializing and celebrating cultural events, fostering a strong sense of identity and belonging among Vietnamese immigrants. The enduring importance of Little Saigons to Vietnamese Americans underscores the need for their protection and preservation, a sentiment that extends to other ethnic enclaves as well.

Design of an iron Warren Girder R. R. Bridge

Thu, 01 Jan 1874 00:00:00 GMT

Design of an iron Warren Girder R. R. Bridge Hongma, A. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1874

A study of the effect of moisture on the curing of cement

Tue, 01 Jan 1935 00:00:00 GMT

A study of the effect of moisture on the curing of cement Muldowney, Francis W.; Presby, Lorin A. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1935

A theoretical analysis of the stress distribution, due to wheel loads in the subgrade under pavements of flexible type

Tue, 01 Jan 1935 00:00:00 GMT

A theoretical analysis of the stress distribution, due to wheel loads in the subgrade under pavements of flexible type Lavenás, Carlos Fernando.; Nelson, Bernard Helmer. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1935; Includes bibliographical references (leaf 47).

A housing plan for Cambridge, Mass.

Tue, 01 Jan 1935 00:00:00 GMT

A housing plan for Cambridge, Mass. Howard, John T. (Cartographer) Thesis: B. Arch., Massachusetts Institute of Technology, Department of City Planning, 1935

Soot formation in laminar diffusion flames

Wed, 01 Jan 1958 00:00:00 GMT

Soot formation in laminar diffusion flames Jarnagin, L. Alan.; Vahlsing, David H. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1958; Includes bibliographical references (leaves 43-44).

Bicycle rim brake: investigation of a promising friction material and development of performance specificiations.

Fri, 01 Jan 1971 00:00:00 GMT

Bicycle rim brake: investigation of a promising friction material and development of performance specificiations. Hanson, Brian Donald. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1971; Bibliography: leaf 20.

An optimizing quad translator

Tue, 01 Jan 1985 00:00:00 GMT

An optimizing quad translator Strong, E. Gordon. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1985; Bibliography: leaf 50.

Helical rail guns : the application of linear electric motors to aircraft launching

Fri, 01 Jan 1982 00:00:00 GMT

Helical rail guns : the application of linear electric motors to aircraft launching Fitch, Osa Edward. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1982; Vita.; Includes bibliographical references (leaf 185).

Explanatory to a design for the buildings of the water works of a city, embracing the treatment of a system of beams, of an iron arch rib with bracings, of the stability of the chimney and of the tower, and of the pieces of a roof truss covering a small building

Wed, 01 Jan 1873 00:00:00 GMT

Explanatory to a design for the buildings of the water works of a city, embracing the treatment of a system of beams, of an iron arch rib with bracings, of the stability of the chimney and of the tower, and of the pieces of a roof truss covering a small building Phillips, Henry Ayling, 1852-1926. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1873

A study of promotional activity in electrical domestic rate structures

Tue, 01 Jan 1935 00:00:00 GMT

A study of promotional activity in electrical domestic rate structures Edgar, Edward Cooper. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1935; Appendix contains numerous pamphlets.; Includes bibliographical references.

A civic center for Bridgeport, Connecticut

Tue, 01 Jan 1935 00:00:00 GMT

A civic center for Bridgeport, Connecticut Brazel, Frank J. Thesis: B. Arch., Massachusetts Institute of Technology, Department of City Planning, 1935

Alternative design for the compound archery bow

Wed, 01 Jan 1992 00:00:00 GMT

Alternative design for the compound archery bow Griffith, Deanna Lee. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1992; Includes bibliographical references (leaf 65).

Multiplexed network commnication for secure operating systems

Sun, 01 Jan 1978 00:00:00 GMT

Multiplexed network commnication for secure operating systems Ciccarelli, Eugene Charles. Thesis: Elec. E., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1978; Bibliography: leaves 247-251.

Creative design applied on tape recorder

Sun, 01 Jan 1956 00:00:00 GMT

Creative design applied on tape recorder Tang, Arthur Y. C. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1956; Bibliography: leaf 29.

Classification yard effects in rail freight movement reliability.

Sat, 01 Jan 1972 00:00:00 GMT

Classification yard effects in rail freight movement reliability. O'Doherty, John Desmond. Thesis: Civ. E., Massachusetts Institute of Technology, Department of Civil Engineering, 1972; Bibliography: leaf. 117.

A study of the organization and operating methods of the Department of Street Railways of the City of Detroit

Mon, 01 Jan 1923 00:00:00 GMT

A study of the organization and operating methods of the Department of Street Railways of the City of Detroit Ames, William Edley.; Evans, Roger Jackson. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1923

Machine Learning for Physics: from Symbolic Regression to Quantum Simulation

Wed, 01 May 2024 00:00:00 GMT

Machine Learning for Physics: from Symbolic Regression to Quantum Simulation Dugan, Owen Michael In this thesis, we explore the application of machine learning (ML) methods to problems in physics. Because ML has revolutionized a wide range of fields, it is natural to ask whether it may be a valuable tool for physics. Physics applications present a challenge as many physics problems have a precise mathematical definition and a classical (non-ML-based) solution, making ML models less likely to outperform existing techniques. In this paper, we focus on two general problems for which ML techniques provide an improvement as compared to existing techniques in physics: 1) fast simulation, and 2) discovering new physics. To illustrate the potential of ML to advance physics by solving these problems, we develop a physics-optimized ML model for each of the problems identified above, respectively: 1) Q-Flow, a technique for faster bosonic quantum simulation using normalizing flows to simulate a compressed representation of a quantum state, and 2) OccamNet, a framework for scientific discovery through novel algorithms for efficient and parallelizable symbolic regression. Our methods demonstrate the potential for ML as a valuable tool for physics research.

MEMS Simulations and Waveguide Loss Analysis forPhotonic Integrated Circuits

Wed, 01 May 2024 00:00:00 GMT

MEMS Simulations and Waveguide Loss Analysis forPhotonic Integrated Circuits Binbas, Berkin Microelectromechanical systems (MEMS) are promising candidates to be used in photonic integrated chips (PICs) for applications. While there are a variety of MEMS devices used for different purposes, the main concern of this thesis will be the using MEMS as phase shifters and understanding waveguide losses. MEMS devices can be actuated by applying a potential difference, and can be used to adjust the phase shift of light travelling through the waveguides. The shift is observed as a result of the change of the physical distance between the cantilever and the fixed waveguides buried on the surface of the chips. Due to their ease of activation, ability to precisely control the phase shift, and small heat footprint, these devices are excellent candidates for cryogenic applications, such as quantum computers. In this work, we present a summary of the literature regarding the MEMS devices, and investigate their working principles. We introduce a simple theoretical model for understanding the two biggest source factors in characterization of MEMS devices: bending and propagation losses. We then present the experimental setup through used for performing loss measurements on a fabricated chip. We look at simulation results for understanding the behavior of the cantilever, perform loss analysis on measurements, and conclude with potential issues to be resolved for the devices to work as intended in the future.

Paleomagnetic Investigation of Enstatite Chondrite Chondrules: Implications for the Solar Nebula

Wed, 01 May 2024 00:00:00 GMT

Paleomagnetic Investigation of Enstatite Chondrite Chondrules: Implications for the Solar Nebula Mastrola, Becca The early stages of solar system formation were characterized by the rapid evolution of the protoplanetary disk. A magnetic field governed the highly efficient mass and angular momentum transport systems. Paleomagnetic measurements of chondrites have constrained the intensity of the nebular field between ∼3-7 AU. Previous work on two dusty olivine chondrules from high iron enstatite chondrites with variable kamacite grain sizes implied strong inner nebular field (∼1-2 AU) intensities of 185 ± 111 µT and 299 ± 247 µT. One new dusty olivine chondrule, containing exclusively submicron kamacite grains, suggested an inner nebular field intensity of 15.2 ± 12.4 µT. The wide field strength error margins and seemingly low-coercivity grains limit the reliability of calculated paleointensities from these chondrules. Thus, the paleointensity of the inner nebular field cannot be definitively constrained by the magnetizations of the dusty olivine chondrules.

Reconstructing Dark Photons with the DarkQuest Experiment at Fermilab

Wed, 01 May 2024 00:00:00 GMT

Reconstructing Dark Photons with the DarkQuest Experiment at Fermilab Scheuller, Ellison J. The DarkQuest experiment will search for dark photons by looking for their decay into standard model leptons which can be detected. DarkQuest will use the momentum of these standard model leptons to calculate the position or vertex where the dark photons decay. Looking at the vertex positions will show if a dark photon was detected and if it is, physicists will be able to confirm DM predictions and learn a lot about the nature of dark matter which has yet to be detected. We use simulation to study the performance of the vertex reconstruction algorithm that will be used on DarkQuest when it starts taking real data. The vertex is calculated using the vertex reconstruction algorithms which are outlined in this thesis. The performance of the algorithm is then analyzed by looking at the vertex reconstruction efficiency, sensitivity, and displaced dimuon mass resolution.

Ancient Art, Modern Tech: Experiencing the Digital Reinvention of the Mogao Grottoes

Wed, 01 May 2024 00:00:00 GMT

Ancient Art, Modern Tech: Experiencing the Digital Reinvention of the Mogao Grottoes Zhao, Celina(Celina T.) Built from the 4th to 14th century, the Mogao Grottoes in the deserts of northwestern China is the greatest repository of Buddhist art in the world. It has long faced a range of threats from natural disasters to imperialistic plunder. But now it must confront the greatest challenge to its continued existence: modern-day tourism. The sheer volume of visitors seeking a direct experience of this unique but delicate site has resulted in an increasingly rapid process of destruction in the 21st century. Its guardian institution, the Dunhuang Academy (DA), has thus embarked on an ambitious, decades-long undertaking that puts technology at the core of its mission to protect, research, and promote the site. Today, digital resources, replicas, and exhibitions have redefined what it means to experience the caves. Together, they have also expanded Mogao’s reach far beyond its physical boundaries. Against all odds, this middle-of-nowhere desert outpost has emerged as a global pioneer of digital conservation and restoration. It’s a model that can be exported to other fragile sites across the world. This thesis compiles a comprehensive history of Dunhuang’s journey and raises questions about what it means to “authentically experience” such cultural heritage today.

Developing a climatology for dry thunderstorms and associated environmental conditions in the contiguous United States

Wed, 01 May 2024 00:00:00 GMT

Developing a climatology for dry thunderstorms and associated environmental conditions in the contiguous United States Lin, Phoebe Dry thunderstorms are the result of an interesting balance of meteorological variables: they require sufficient moisture and instability in the atmosphere, but also a dry surface layer that facilitates evaporation of falling precipitation. Here, lightning flashes and precipitation amounts for the contiguous United States from 2012-2022 are analyzed, comparing topography, relative humidity, seasonality, hour of the day, and other variables to identify patterns in dry thunderstorms. Dry flash density is found to peak in the Southwestern United States, and the dry lightning fraction for a threshold of 2.5 mm is greater than 1/2 in most of the areas west of the Rocky Mountains. Dry flashes are most active in the JJA and SON, but their location shifts west as the warm season progresses. The distribution of precipitation amounts associated with lightning suggest a difference in environments associated with dry thunderstorms and those that are too wet to be considered dry. The patterns identified here will be useful in preparing for hazards associated with dry thunderstorms.

A Photometric Investigation of the Major Uranian Satellites

Wed, 01 May 2024 00:00:00 GMT

A Photometric Investigation of the Major Uranian Satellites Colclasure, Abigail M. The Uranian system is one of the most unusual in the Solar System and its formation and evolution are poorly understood. Voyager 2 revealed that the major satellites have complex geologic features, including craters, fault systems, and chasmata. The Uranian system has been understudied and current knowledge is limit by a lack of data. The 2023-2032 decadal survey ranked a flagship NASA mission to Uranus, with a required launch window of the early 2030s, as a top priority. Further study is urgently needed, both scientifically and to inform mission planning. We conducted a photometric study, primarily using MIT’s Wallace Astrophysical Observatory, and report the lightcurves of Titania and Oberon in the Sloan g’, r’, and i’ filters. Further observations from larger telescopes are needed, but these data may indicate that ice on both Titania and Oberon has redistributed since the Voyager epoch.

The Effect of Temperature on the Material Stiffness of Field Hockey Balls for Material Selection

Wed, 01 May 2024 00:00:00 GMT

The Effect of Temperature on the Material Stiffness of Field Hockey Balls for Material Selection Ladd, Liberty R. It is well known that temperature affects the material properties of polyvinyl chloride (PVC). In particular, field hockey players report balls made of PVC breaking in half when hit in cold weather. Hockey ball manufacturers are interested in the effect of temperature on balls breaking to inform ball design and material selection. To test whether hockey balls are easier to break in cold temperatures, this study measured the material stiffness [N/mm] of hockey balls at temperatures between -4°C and 23°C using an Instron Universal Testing Machine (UTM). For white PVC hockey balls, this study finds for every 1 degree increase in temperature, there is a 3.44 ± 0.64 N/mm decrease in material stiffness. For yellow and orange PVC hockey balls, there is a 4.91 ± 1.00 N/mm decrease in material stiffness for every 1 degree increase in temperature. A higher material stiffness results in a lower force threshold for brittle fracture. The results indicate that hockey balls are more likely to break at lower temperatures regardless of color. White PVC hockey balls are less likely to break at lower temperatures than orange or yellow PVC hockey balls. This study additionally compares this effect to a white prototype ball made of a different material (polyurethane) and finds there is an 11.32 ± 4.10 N/mm decrease in material stiffness for every 1 degree increase in temperature for the prototype ball.

Design of an Adjustable Compression Glove for Hand Arthritis

Wed, 01 May 2024 00:00:00 GMT

Design of an Adjustable Compression Glove for Hand Arthritis Chen, Sophia Hand osteoarthritis (HOA) is one of the most common forms of arthritis, resulting in pain, aching, stiffness, and inflammation of the joints. One method of alleviating these symptoms is the use of compression gloves, which promote circulation in the hands. However, conventional compression gloves pose several user-based challenges: they are difficult to don/doff; only apply static pressure; and can be uncomfortable, thereby disincentivizing use. Introducing dynamic, shape changing behavior to compression gloves through the use of pneumatics can provide a promising alternative to these limited, conventional forms. Moreover, a pneumatic system allows for high levels of compression that are instantaneous and adjustable. This work explores the design of a pneumatically-actuated adjustable compression glove. The prototype is defined through user needs and is validated through compression testing, successfully and repeatedly producing pressure levels beyond the 3.73 kPa goal defined for HOA in the finger joints.

A development in East Boston, Massachusetts

Tue, 01 Jan 1935 00:00:00 GMT

A development in East Boston, Massachusetts Waferling, John J. Thesis: B. Arch., Massachusetts Institute of Technology, Department of City Planning, 1935; Includes bibliographical references.

Operating and financial policy of the New York, New Haven and Hartford Railroad, 1921-1926

Sun, 01 Jan 1928 00:00:00 GMT

Operating and financial policy of the New York, New Haven and Hartford Railroad, 1921-1926 Larkin, George V. (George Vincent) Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1928; Includes bibliographical references (leaf xlix).

A study of rotational flow in a pipe line

Tue, 01 Jan 1935 00:00:00 GMT

A study of rotational flow in a pipe line Bull, G. R.; Winiarski, K. J. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1935

An experimental investigation of the efficiency of "Teco Rings" in transmitting stress

Tue, 01 Jan 1935 00:00:00 GMT

An experimental investigation of the efficiency of "Teco Rings" in transmitting stress Bates, William J., 1811?-; Ostlund, John J. Thesis: B.S., Massachusetts Institute of Technology, Department of Architectural Engineering, 1935; Accompanied by charts in a folder.

A simulation of New Haven railroad freight train and yard operations

Tue, 01 Jan 1963 00:00:00 GMT

A simulation of New Haven railroad freight train and yard operations Lindquist, Robert Evans, Jr. Thesis: B.S., Massachusetts Institute of Technology, School of Industrial Management, 1963; Appendix contains numerous pamphlets.; Includes bibliographical references (leaf [67]).

The self-service ice cream cabinet

Wed, 01 Jan 1958 00:00:00 GMT

The self-service ice cream cabinet Hess, August P. Thesis: B.S., Massachusetts Institute of Technology, School of Industrial Management, 1958

Weapons systems development in the Air Force

Wed, 01 Jan 1958 00:00:00 GMT

Weapons systems development in the Air Force Henry, Charles Joseph. Thesis: B.S., Massachusetts Institute of Technology, School of Industrial Management, 1958; Includes bibliographical references (leaves [52]-[53]).

Quantitative selection of advertising media

Wed, 01 Jan 1958 00:00:00 GMT

Quantitative selection of advertising media Heimbach, Warren W. Thesis: B.S., Massachusetts Institute of Technology, School of Industrial Management, 1958; Includes bibliographical references (leaves [44]-[45]).

The nature of "trapped oil" in a porous medium

Wed, 01 Jan 1958 00:00:00 GMT

The nature of "trapped oil" in a porous medium Herman, John J. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1958; Includes bibliographical references (leaf 21).

Direct synthesis of acetylene from carbon and hydrogen

Wed, 01 Jan 1958 00:00:00 GMT

Direct synthesis of acetylene from carbon and hydrogen Hausslein, Robert W. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1958; Includes bibliographical references (leaf 30).

The application of electrophoresis to separation processes

Wed, 01 Jan 1958 00:00:00 GMT

The application of electrophoresis to separation processes Hanson, Jens L. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1958; Includes bibliographical references (leaf 28).

Measurement of water saturation during two phase flow through a porous medium by electrical methods

Wed, 01 Jan 1958 00:00:00 GMT

Measurement of water saturation during two phase flow through a porous medium by electrical methods Hahn, Christopher K.; Hartman, Henry E. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1958; Includes bibliographical references (leaf 97).

A method for the assessment of mutually exclusive scenarios in the risk assessment of high-level waste disposal in deep geologic formations

Sun, 01 Jan 1984 00:00:00 GMT

A method for the assessment of mutually exclusive scenarios in the risk assessment of high-level waste disposal in deep geologic formations Ottinetti, Luca. Thesis: Nuc. E., Massachusetts Institute of Technology, Department of Nuclear Engineering, 1984; Includes bibliographics references.

The design of a yacht club to be placed in a city

Wed, 01 Jan 1913 00:00:00 GMT

The design of a yacht club to be placed in a city Swenson, Guy A. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1913

The rate of heat of hydration of neat cement, as affected by a few chemical admixtures

Tue, 01 Jan 1935 00:00:00 GMT

The rate of heat of hydration of neat cement, as affected by a few chemical admixtures Bechstein, Fred J.; De St. Malo, Alberto. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1935; Includes bibliographical references (leaf 39).

A comparison of rates of return on investment between public and private electric utilities in Massachusetts

Tue, 01 Jan 1935 00:00:00 GMT

A comparison of rates of return on investment between public and private electric utilities in Massachusetts Banquer, Irving S. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1935

A study of methods of accounting for unused facilities

Tue, 01 Jan 1935 00:00:00 GMT

A study of methods of accounting for unused facilities Ballard, John B.; King, Arthur M. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1935; Appendix contains numerous pamphlets.

Graphical analysis of recovery voltage across a resistance-shunted circuit breaker

Thu, 01 Jan 1959 00:00:00 GMT

Graphical analysis of recovery voltage across a resistance-shunted circuit breaker Lehner, Theodore James. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1959; Includes bibliographical references (leaves 22-23).

Stability criteria for numerical integration methods.

Fri, 01 Jan 1971 00:00:00 GMT

Stability criteria for numerical integration methods. Glover, Keith. Thesis: Elec. E., Massachusetts Institute of Technology, Department of Electrical Engineering, 1971; Includes bibliographical references.

A city hall for a city of seventy-five thousand inhabitants

Fri, 01 Jan 1904 00:00:00 GMT

A city hall for a city of seventy-five thousand inhabitants Swenson, Omar S. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1904

The properties of amorphous and microcrystalline Ni - Nb alloys.

Sun, 01 Jan 1978 00:00:00 GMT

The properties of amorphous and microcrystalline Ni - Nb alloys. Clay, Carolyne. Thesis: Metal. E., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 1978; Includes bibliographical references.

Revolt, Passion, Freedom: A Collection of Short Stories Exploring Absurdism

Thu, 01 Feb 2024 00:00:00 GMT

Revolt, Passion, Freedom: A Collection of Short Stories Exploring Absurdism Liu, Frank In the face of a rapidly changing and turbulent world, many people around the world are beginning to turn away from established orthodoxies of thought. In doing so, they may feel lost in the world, as all previous ideas of meaning to life may lose their allure. This paper explores the ideas of the absurdism movement and aims to familiarize readers with absurdism. To do so, the philosophy is explained in the preface before being explored in a collection of three fictional short stories that each focus on a facet of absurdism (revolt, passion, and freedom), and explores the ubiquity of its themes through different settings and times. The format of short stories was chosen due to its ability to connect readers with the characters and ideas presented within, making it a powerful tool to convey these messages of absurdism.

Locomotive superheaters and feed water heaters

Sun, 01 Jan 1922 00:00:00 GMT

Locomotive superheaters and feed water heaters Powell, Bryan B. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1922; Includes bibliographical references (leaf 4).

A cost accounting system for the F. L. & J. C. Codman Company buffing wheels

Tue, 01 Jan 1935 00:00:00 GMT

A cost accounting system for the F. L. & J. C. Codman Company buffing wheels Bailey, Richard F.; Loomis, John D. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1935

Rehabilitation study for the outer South End in Boston

Tue, 01 Jan 1935 00:00:00 GMT

Rehabilitation study for the outer South End in Boston Babcox, Henry C. Thesis: B. Arch., Massachusetts Institute of Technology, Department of City Planning, 1935; Appendix contains numerous pamphlets.; Includes bibliographical references.

General manufacturing analysis of a boiler works

Wed, 01 Jan 1936 00:00:00 GMT

General manufacturing analysis of a boiler works Stiles, Winthrop A. (Winthrop Alan); Tobey, J. Lawrence Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1936; Includes bibliographical references (leaf 45).

Photographic materials for interferometer, schlieren, and shadowgraph apparatus

Thu, 01 Jan 1953 00:00:00 GMT

Photographic materials for interferometer, schlieren, and shadowgraph apparatus Henry, John Robert. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1953; Includes bibliographical references (leaves 37-38).

An investigation of high frequency fluorescent lighting

Thu, 01 Jan 1953 00:00:00 GMT

An investigation of high frequency fluorescent lighting Eglowstein, Ira. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1953; Bibliography: leaf 32.

Design of a genuflector.

Sat, 01 Jan 1972 00:00:00 GMT

Design of a genuflector. Eckert, Richard Russell. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1972; Bibliography: leaf 23.

A controlled community for Waterbury, Connecticut

Wed, 01 Jan 1936 00:00:00 GMT

A controlled community for Waterbury, Connecticut Tremaglio, Angelo M. (Angelo Michael); Viola, John D. Thesis: B.S., Massachusetts Institute of Technology, Department of Building Engineering and Construction, 1936

An investigation of the qualitative high-lift characteristics of three representative Davis airfoils

Fri, 01 Jan 1943 00:00:00 GMT

An investigation of the qualitative high-lift characteristics of three representative Davis airfoils Spear, Ernest M. Thesis: B.S., Massachusetts Institute of Technology, Department of Aeronautical Engineering, 1943; Includes bibliographical references (leaf 12).

An airline terminal building for Providence, Rhode Island

Wed, 01 Jan 1958 00:00:00 GMT

An airline terminal building for Providence, Rhode Island Ten Eyck, John Braid. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1958; Includes bibliographical references (leaf 31).

A residence for Miss Frances Murphy at Bradenton, Florida.

Wed, 01 Jan 1964 00:00:00 GMT

A residence for Miss Frances Murphy at Bradenton, Florida. Zoller, William Curry. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1964

A parametric study of the stress distribution in a four-celled box beam model of the ASR-21 Class Catamaran cross-structure.

Sat, 01 Jan 1972 00:00:00 GMT

A parametric study of the stress distribution in a four-celled box beam model of the ASR-21 Class Catamaran cross-structure. Fenton, Paul Herbert. Thesis: Ocean E., Massachusetts Institute of Technology, Department of Ocean Engineering, 1972; Includes bibliographical references.

Evaluation of two tactile speech displays

Sun, 01 Jan 1978 00:00:00 GMT

Evaluation of two tactile speech displays Clements, Mark Andrew. Thesis: Elec. E., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1978; Bibliography: leaves 57-59.

Simple model of energy dissipation distribution of 3 MeV electrons in non-uniform material

Sun, 01 Jan 1978 00:00:00 GMT

Simple model of energy dissipation distribution of 3 MeV electrons in non-uniform material Clark, Patricia Ellen. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1978; Includes bibliographical references.

Co-ordinate squares : a solution to many chess pawn endgames

Sun, 01 Jan 1978 00:00:00 GMT

Co-ordinate squares : a solution to many chess pawn endgames Church, Kenneth Ward. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1978; Bibliography: leaf 55.

Ultimate load analysis using finite element methods

Sun, 01 Jan 1978 00:00:00 GMT

Ultimate load analysis using finite element methods Cimento, Arthur Peter. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1978; Includes bibliographical references.

Kinematic Chain Modelling of Rotary System as Applied to a Selectric Typewriter

Fri, 01 Sep 2023 00:00:00 GMT

Kinematic Chain Modelling of Rotary System as Applied to a Selectric Typewriter Mitchell, Joshua Kinematic chains were created for the rotation and tilting mechanisms of an IBM Selectric II Typewriter. The chain for the rotation mechanism was used to create a homogeneous transform matrix system that allowed the position of the printing character in a local coordinate system to be represented in the global coordinate system through a series of shape and joint matrix transforms. This allowed the position and rotation of the character of interest to be calculated based on a commanded motion at a certain joint. A drive error in that joint, representing a spring losing stiffness, was also included in the transform system and influenced the final values of position and rotation. A particular error value of .01745 radians was used along with a commanded motion of .07667 radians. This resulted in a final rotation of the printhead of .3079 radians, which is an increase of .0233 over the value obtained with no drive error. This same technique could be applied to determine the feasibility of future rotary manufacturing systems.

Test of 72,000,000 gallon pumping engine of Boston (main drainage pumping station)

Tue, 01 Jan 1907 00:00:00 GMT

Test of 72,000,000 gallon pumping engine of Boston (main drainage pumping station) Kelly, E. F. (Evander Francis), 1879-; Kudlich, R. H. 1883- Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1907

The effect of dissolved oxygen on the corrosion of copper by high velocity water

Wed, 01 Jan 1958 00:00:00 GMT

The effect of dissolved oxygen on the corrosion of copper by high velocity water Hadge, Ronald G. (Ronald George); Revelotis, Dennis C. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1958; Includes bibliographical references (leaves 40-51).

An application of resource allocation techniques

Tue, 01 Jan 1963 00:00:00 GMT

An application of resource allocation techniques Brach, John Richard. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1963; Includes bibliographical references (leaf 19).

The effect of dissolved oxygen by the corrosion of copper by high velocity water

Fri, 01 Jan 1954 00:00:00 GMT

The effect of dissolved oxygen by the corrosion of copper by high velocity water Fish, Robert L. (Robert Louis); Dankese, Joseph P. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1954; Includes bibliographical references (leaves 38-39).

An isolated urban community.

Wed, 01 Jan 1964 00:00:00 GMT

An isolated urban community. Richards, Frank Henry Benham. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1964

A theater for the Greek landscape.

Wed, 01 Jan 1964 00:00:00 GMT

A theater for the Greek landscape. Sapounakis, Paul Savas. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1964

Design of frequency dependent impedance for transmission line modeling.

Sat, 01 Jan 1972 00:00:00 GMT

Design of frequency dependent impedance for transmission line modeling. Feero, William Edward. Thesis: Elec. E., Massachusetts Institute of Technology, Department of Electrical Engineering, 1972; Includes bibliographical references.

Design of a pacemeker electrode testing device.

Sat, 01 Jan 1972 00:00:00 GMT

Design of a pacemeker electrode testing device. Erwin, Lewis, 1951-1991. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1972; Includes bibliographical references.

A software system for the Honeywell oculometer.

Sat, 01 Jan 1972 00:00:00 GMT

A software system for the Honeywell oculometer. Errecart, Michael Terry. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1972

A programmable corrupted channel simulator.

Sat, 01 Jan 1972 00:00:00 GMT

A programmable corrupted channel simulator. Esten, David Richard. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1972

The North-Eastern Fishery question since 1886, a record of diplomatic relations

Thu, 01 Jan 1891 00:00:00 GMT

The North-Eastern Fishery question since 1886, a record of diplomatic relations Roots, Willard Holt. Thesis: B.S., Massachusetts Institute of Technology, Department of General Studies, 1891; Includes bibliographical references.

The motor truck vs the railroads as a means of freight transportation from Boston to New England points

Thu, 01 Jan 1925 00:00:00 GMT

The motor truck vs the railroads as a means of freight transportation from Boston to New England points Billman, Charles M. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1925; Appendix contains numerous pamphlets.; Includes bibliographical references (leaf 63).

A working routine for the three-color carbon process of color photography

Wed, 01 Jan 1908 00:00:00 GMT

A working routine for the three-color carbon process of color photography Jones, M. T. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1908; Includes bibliographical references.

Production of bleaching powder by the fluidized powder technique.

Mon, 01 Jan 1945 00:00:00 GMT

Production of bleaching powder by the fluidized powder technique. Wunderlich, Mario R. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1945; Bibliography: leaf 42.

Air - stream atomization of liquids,

Mon, 01 Jan 1945 00:00:00 GMT

Air - stream atomization of liquids, Trageser, David A. (David Adam); Thorkilsen, Harold. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1945; Bibliography: leaves 43-44.

Production of water gas by fluidized powder technique,

Mon, 01 Jan 1945 00:00:00 GMT

Production of water gas by fluidized powder technique, Poorman, Richard M.; Sluis, Peter. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1945; Bibliography: leaf 68.

The effect of inorganic salts on the vapor - liquid equilibrium of inorganic acids.

Mon, 01 Jan 1945 00:00:00 GMT

The effect of inorganic salts on the vapor - liquid equilibrium of inorganic acids. Ruehrmund, Max E. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1945; Bibliography: leaf 43.

Automatic generation of vapor-liquid equilibrium data.

Sat, 01 Jan 1966 00:00:00 GMT

Automatic generation of vapor-liquid equilibrium data. Cukor, Peter Myron. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1966; Bibliography: leaves 109-110.

Solvent extraction of tung oil press cake.

Mon, 01 Jan 1945 00:00:00 GMT

Solvent extraction of tung oil press cake. Lacroix, Arthur Jacques. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1945; Bibliography: leaf 24.

The reduction of visibility due to smoke at the East Boston airport.

Mon, 01 Jan 1945 00:00:00 GMT

The reduction of visibility due to smoke at the East Boston airport. Kennedy, Norman C. Thesis: B.S., Massachusetts Institute of Technology, Department of General Science, 1945

A supreme court of law for India.

Wed, 01 Jan 1964 00:00:00 GMT

A supreme court of law for India. Sikri, Ravi. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1964

Design and construction of submersible hand controllers

Thu, 01 Jan 1981 00:00:00 GMT

Design and construction of submersible hand controllers Shain, Eric Brian. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1981; Lacks leaf 38.

Study of the Fermi surface of alkali-metal graphite intercalation compounds using the Shubnikov-de Haas measurements

Thu, 01 Jan 1981 00:00:00 GMT

Study of the Fermi surface of alkali-metal graphite intercalation compounds using the Shubnikov-de Haas measurements Shayegan, Mansour. Thesis: Elec. E., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1981; Includes bibliographical references.

Investigating Variation in Launch Vehicle Atmospheric Impact by Launch Latitude and Season

Thu, 01 Jun 2023 00:00:00 GMT

Investigating Variation in Launch Vehicle Atmospheric Impact by Launch Latitude and Season McDonald, Helena Launch vehicles are a significant anthropogenic atmospheric emissions vector, and in the past have been shown to cause up to 50% as much global heating as aviation CO2. Despite this high magnitude of emissions impact, few studies quantify the variation in launch vehicle emissions beyond exploring launch number or propellant type, and as such there are few proposed avenues for reducing industry impact. Here, we present two new factors which may be relevant for reducing emissions impact; launch location (hemisphere) and launch season. I perform five two-year GEOS-Chem High Performance simulations, modeling the impact of 3000 Falcon-Heavy launches respectively across the months of January and July from Cape Canaveral in Florida and Rocket Lab Launch Complex in New Zealand. By examining zonal mean ozone and stratospheric water vapor accumulation, we find significant evidence for seasonal and hemispheric variation of launch vehicle emissions impact, leading to between 2 and 5 times as much ozone accumulation in summer versus winter launches for the same hemisphere, and 1.2-1.5x greater accumulation for southern hemisphere launches across the same launch season. The extent of these impacts provides substantial motivation for regulating and reducing summer-season and southern-hemisphere launches.

Egyptian Blue Pigment: An Examination of Effects on Luminescence from the Partial Replacement of Cu with Mg, and the Optimization of Atomic Imaging to Prevent Sample Damage

Sun, 01 May 2022 00:00:00 GMT

Egyptian Blue Pigment: An Examination of Effects on Luminescence from the Partial Replacement of Cu with Mg, and the Optimization of Atomic Imaging to Prevent Sample Damage Mittman, Sophia This research examines the correlation between Egyptian blue pigment luminescence and magnesium inclusions, in addition to atomic imaging of ancient Egyptian blue. Egyptian blue (CaCuSi4O10 crystals and a flux matrix) was the first synthetic pigment created, discovered by ancient Egyptians around 3000 BC. This material has merit both as a stable synthetic pigment that has lasted thousands of years, but also as a modern material under study for uses in energy-saving applications due to its near-infrared luminescence. To engineer Egyptian blue and maximize its luminescent properties, understanding how various inclusion atoms affect the microstructure of Egyptian blue is critical. Current studies observe that magnesium inclusions increases luminescence. Thus, the first module of this thesis correlates Egyptian blue luminescence with the partial replacement of copper with magnesium. Analyses including scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS), and Raman spectroscopy were performed. It was found that magnesium trends towards sodium-rich phases, forms clumps of entirely different phases, and does not itself luminesce. Given these results, further studies are needed to identify why luminescence is, in fact, enhanced by magnesium inclusions, since intensity of luminescence was not measured in this study. In the second module of this research, both modern and ancient samples of Egyptian blue were exfoliated and examined under scanning transmission electron microscopy (STEM). The underlying goal was to quantify compositional changes across crystalline-amorphous interfaces to accurately estimate original Egyptian blue formulae. However, each sample was damaged when STEM was performed. Thus, beam energies and microscope settings were altered in attempts to prevent this damaging. Before damaging occurred, though, high-resolution images of atoms in the cuprorivaite lattice were imaged, which is the first Egyptian blue atomic imaging of its kind.

Explaining a Low-Temperature Magnetic Order in Annealed van der Waals Semiconductor CrSBr

Thu, 01 Jun 2023 00:00:00 GMT

Explaining a Low-Temperature Magnetic Order in Annealed van der Waals Semiconductor CrSBr Song, Samuel W. The van der Waals semiconductor CrSBr stands out as a promising 2D magnetic material due to its high ferromagnetic ordering temperature (135 K), near-infrared direct bandgap (1.5 eV), and stability in air. In this thesis we report on the detection of a low-temperature magnetic order in annealed CrSBr bulk single crystals using SQUID magnetometry. The order manifests as a broad bump centered at 75 K in magnetization measurements. We deduce that the order is the magnetic contribution of secondary phases, which we image and identify via SEM-EDS analysis. We determine that the secondary phase Cr₂S₃ is formed during annealing at 750°C or above and that the secondary phase CrBr₃ is also formed during annealing at 850°C.

A Gear Hobbing Attachment for Manual Milling Machines to Facilitate the Production of Exotic Gears for Full-Scale Working Prototypes

Thu, 01 Feb 2024 00:00:00 GMT

A Gear Hobbing Attachment for Manual Milling Machines to Facilitate the Production of Exotic Gears for Full-Scale Working Prototypes Sieniewicz, Satchel H. This thesis aims to present the design, development, and fabrication of a gear hobbing attachment tailored for manual milling machines. The primary objective is to create a versatile, cost-effective tool that streamlines production of standard and exotic gears, with a specific focus on gears needed to create full-scale working prototypes, to test the performance of the gear train and to ready prototypes for pre-manufacture analysis. This approach seeks to replace the industry-standard prototyping method of manual indexing, which is time-consuming and error-prone, with a more efficient, reliable approach that mirrors the gear hobbing process used for industrial production. The distinctive advantages of this gear hobbing attachment would be especially relevant for creating worm, helical, and screw gears. Because of their complex geometries, these gear types are effectively impossible to produce through conventional manual methods. Currently, producing such gears requires dedicated gear cutting machines and skilled operators, which drastically raises the cost of producing such gears for a prototype. For startup designers and labs, while using a CNC machine with a 4th axis is a feasible option for creating certain gear components, this approach can be time-consuming and challenging to set up. It requires special CAM software packages and programming skills, along with the use of very small cutters, making it primarily viable for gears with larger modules, typically 1.5 and above. [9] The proposed gear hobbing attachment would make the creation of production-accurate prototypes simpler, less costly and more accessible. This innovation would also make it practical to create gear aspect ratios typically unavailable in standard gear catalogs, such as large ring gears or thin worm wheels, providing greater design freedom and flexibility in prototype development. The proposed gear hobbing attachment will consist of a spindle mounted to the bed of the manual milling machine with an AC servo motor for drive.

The resistance of the voltaic arc

Thu, 01 Jan 1891 00:00:00 GMT

The resistance of the voltaic arc White, J. Francis.; Ensworth, H. H. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1891

A metropolitan police station for the city of Manila

Wed, 01 Jan 1941 00:00:00 GMT

A metropolitan police station for the city of Manila Arguelles, Carlos Corcuera. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1941; Includes bibliographical references (leaf 35).

The reorganization of the St.Louis - San Francisco Railway Company

Thu, 01 Jan 1948 00:00:00 GMT

The reorganization of the St.Louis - San Francisco Railway Company Morris, James B. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1948; Bibliography: leaves [62-63].

Peptide-Functionalized Layer-by-Layer Nanoparticles Demonstrate Improved Blood Brain Barrier Permeability for Glioblastoma Treatment

Thu, 01 Jun 2023 00:00:00 GMT

Peptide-Functionalized Layer-by-Layer Nanoparticles Demonstrate Improved Blood Brain Barrier Permeability for Glioblastoma Treatment Ganesh, Priya The greatest obstacle in the treatment of glioblastomas is the blood-brain barrier (BBB), the endothelial cells that line the vessels of the brain and are stitched together into a barrier by tight junction complexes. One approach to overcoming this barrier is encapsulating drugs in nanoparticles whose surfaces are engineered (usually, with the addition of ligands) to promote binding to various receptors of the BBB, thus triggering transcytosis and allowing the nanoparticle and its drug contents to cross the BBB. Previous research has shown that electrostatic absorption (as opposed to covalent functionalization) is a quick and effective method for attaching cationic, tumor-penetrating peptides to anionic nanoparticles synthesized through an iterative layer-by-layer (LbL) approach. Here, I demonstrate that LbL nanoparticles functionalized with Angiopep-2, a BBB-penetrating peptide, can penetrate the BBB to deliver their contents to the brain. Peptide-functionalized particles were screened in an in vitro transwell model of the blood-brain barrier, and particularly promising candidates were screened in a mouse model through intravital imaging, leading to a conclusion that the combination of a poly-L-aspartate outer layer and Angiopep-2 leads to significant improvement in nanoparticle uptake in the brain. Future work will include in vivo experiments with peptide-functionalized LbL nanoparticles with a hyaluronic acid (HA) outer layer, as HA particles have been shown to have in vivo transport properties not reflected in in vitro transport experiments.

Nanoparticle Superlattice Processing: Monodispersed Building-Blocks & Single Crystal Films

Thu, 01 Jun 2023 00:00:00 GMT

Nanoparticle Superlattice Processing: Monodispersed Building-Blocks & Single Crystal Films Gatenil, Perapat Pete Nanocomposite tectons (NCTs) offer a versatile method for systematically modulating material properties at the nanoscale. These building blocks are created by grafting nanoparticles with end-terminated polymers comprising supramolecular binding groups, akin to DNA base pair hydrogen bonding. This approach enables the precise organization and assembly of NCT units into macroscopic materials. By adjusting nanoparticle core sizes, polymer brush lengths, and molecular recognition groups, NCTs can be tailored to produce superlattices with controlled crystalline structures, lattice spacing, and geometries. These superlattices have potential applications in photonics, plasmonics, and microfluidicfluidics. While NCTs can be produced in bulk scale, processing these materials into useful devices remains challenging. One major hurdle is the random aggregation of crystals during assembly, which makes it difficult to identify the properties of single NCT crystals. This study investigates methods to process NCTs and their assemblies into monodisperse crystallites and oriented crystal films, using density gradient centrifugation and scratch-directed assembly, respectively. Density gradient centrifugation allows for the separation of NCT assemblies, comprising various-sized crystallites, into discrete monodisperse distributions. This technique was applied to NCTs composed of gold nanoparticles (AuNPs) and iron oxide nanoparticles (IONPs), grafted with a polystyrene (PS) brush end-terminated with either diaminopyridine (DAP) or thymine (Thy) – which serve as a complementary hydrogen bonding pair. Scanning electron microscopy (SEM) analysis of drop-casted assemblies demonstrated the effectiveness of density gradient separation in processing NCT crystallites into size-specific distributions while revealing a crucial relationship between crystallite size and shape. Heterogenous nucleation provides a means for directing assembly in more controlled ways, for example via nano scratch-directed assembly. SEM analysis of scratched substrates revealed that NCTs in contact with scratches exhibit strong alignment and have the potential to form larger single-crystalline superlattices through oriented attachment.

Structural and Thermal Properties of Ignition Resistant Coatings for Reusable Rocket Engines

Sun, 01 May 2022 00:00:00 GMT

Structural and Thermal Properties of Ignition Resistant Coatings for Reusable Rocket Engines Kiel, Christopher M. This thesis relates my investigation of an environmental barrier coating formulation, first developed for Russian RD-180 engines, which prevents ignition due to particle impact on ox-turbopump turbine. Ignition resistant environmental barrier coatings are of particular interest for reusable rocket systems, which have recently suffered oxygen compatibility failures. The study details the fabrication and characterization of the bulk material for use in a thermomechanical model to predict spallation during a flight cycle. From experimentation, the coating has been determined to be a three-phase metal-ceramic composite composed of nickel, cerium borate, and barium alumino-borate glass. These phases have been verified through thermodynamic modeling using FactSage. Thermal properties are similar to IN-718, while mechanical properties such as modulus and density are significantly lower. Initial studies of the crack propagation mechanisms suggest possible toughening of the composite due to the percolation of the ductile phase nickel. When compared to the theoretical stresses and energy release rates at the interface, the coating is expected to survive modern flight conditions. microstructural modification via experimental characterization and numerical analysis of delamination, could make these coatings suitable for modern reusable rocket engines.

Simulation of Inherent Curvature in Thin Film Rings

Thu, 01 Jun 2023 00:00:00 GMT

Simulation of Inherent Curvature in Thin Film Rings Glass, Josh A. One of the most significant challenges in materials science and engineering is to create materials with tailored surface properties that can be controlled and optimized for specific applications. A common problem in this application is the creation of surfaces of minimal area, since many processes such as surface tension and reactivity create an energy penalty for a surface having unnecessary area. Many processes exist to calculate these surfaces for various scenarios, but the goal of this work is to create a simulation for calculating surfaces that not only try to minimize their area, but also try to adhere to a specific curvature, as surfaces which naturally curve are common in nature, especially biomaterials. In fact, any surface treatment process which leaves one side of an interface with a different compressive force than the other side (thermal tempering of glass, cell membrane formation, thin film vapor deposition) can be a suitable target for simulation using this method. The examples displayed in this work all focus on the evolution of the shape of a soap film between two rings, which in the case of minimal area forms a catenoid. It is important to note, however, that the algorithm developed is not constrained to this problem, and any starting mesh of a surface can be input to calculate upon; as many variables as possible have been left entirely generic to create a multipurpose tool that can calculate ideal curved surfaces for thin film materials. The performance of the system lacks what would be required for processing larger models such as foam surfaces, but this work also details methods by which one could further optimize the system for dealing with larger models in a timely fashion.

Characterizing Mechanical and Gas Transport Properties of Nitrile Norbornene (NN) ROMP in Preparation for Analysis of OMe-NN-ROMP Block Copolymers

Thu, 01 Jun 2023 00:00:00 GMT

Characterizing Mechanical and Gas Transport Properties of Nitrile Norbornene (NN) ROMP in Preparation for Analysis of OMe-NN-ROMP Block Copolymers Qian, Sherrie This study characterized the mechanical and gas transport properties of nitrile norbornene ROMP. At a concentration of 0.15 M, the nitrile norbornene was able to successfully ROMP without becoming gel-like allowing for further characterization. The number average molecular weight was found to be 155 kDa with a polydispersity of 31.04. Thermal analysis of the nitrile norbornene ROMP indicated a T subscript g at 150 °C and a degradation temperature at 410 °C. The density nitrile norbornene ROMP was calculated to be 1.046 ± 0.0290 g/cm³. Using a simulation of the repeat unit the Van der Waals volume was found to be 73.4881 ± 0.1674 cm³ mol-1 and subsequently the fractional free volume was shown to be 0.1614 ± 0.028. The permeation of the 6 pure gases through the film were lower compared to OMe-ROMP with the highest permeating gases being He, H₂, and CO₂ . The selectivities for all the gases were higher than OMe-ROMP which is expected given the drop in permeation. The nitrile norbornene film did plasticize in intervals and the specific plasticization pressure is higher than 5 bar which is the CO₂-induced plasticization pressure point for the OMe-nitrile norbornene ROMP one-pot copolymers. Forming a block copolymer using nitrile norbornene ROMP with OMe-ROMP has potential for securing the mechanical stability from the nitrile norbornene ROMP while maintaining the high gas transport performance from the OMe-ROMP.

Modeling Synapse Formation and Growth as a Non-Biological Analog to the Brain

Thu, 01 Jun 2023 00:00:00 GMT

Modeling Synapse Formation and Growth as a Non-Biological Analog to the Brain Fernandez, Sara V. Efficiency in computing systems is a pressing concern as global reliance on machines and automation grows. Leveraging an understanding of the brain's exceptional computational capabilities, this study presents a preliminary nondimensionalized model of synapses, an essential component for developing brain-inspired computing systems. The model simulates a physical analog of synapse formation wherein a single two-nanowire junction in an electrolytic medium undergoes an electric potential, causing electric field-driven ion transport and subsequent filament growth. Simulations allow for the extraction of meaningful parameter relationships as well as governing equations relating both filament length and time, and current and time. By investigating electric potential-driven cation diffusion, the model provides insights for designing more advanced computing technologies. Future directions involve refining assumptions, adapting system geometry for dendritic growth, and modeling an entire nanowire network. This research bridges the gap between brain-inspired and physical computing, paving the way for highly efficient computing systems beyond traditional approaches.

Characterizing Muscle and Subcutaneous Adipose Tissue Imaging Phantoms for NMR Application

Thu, 01 Jun 2023 00:00:00 GMT

Characterizing Muscle and Subcutaneous Adipose Tissue Imaging Phantoms for NMR Application Khatun, Amena Medical imaging techniques are being increasingly used to derive quantitative information, requiring a new type of imaging phantom for validation. Here, we describe the T2 relaxation properties of an emulsified two-phase imaging phantom for validating a nuclear magnetic resonance (NMR) sensor for measuring fluid volume in vivo. The phantoms simulate muscle and subcutaneous adipose tissues (SCAT) and assure the repeatability and accuracy of the technique. We determined that the 40% phantoms model muscle tissue and 70% model SCAT. The microstructure of the 40% phantoms was changed by controlling temperature and stir rate. Lower temperature and stir rate produced phantoms with a significantly larger average droplet size than higher temperature and stir rate. Microstructure changes did not alter the T2 relaxation behavior (p = 0.05) but altered relative diffusion time. We changed the fabrication protocol by comparing reagent-grade peanut oil to cooking-grade peanut oil and creating the water and lipid phases separately versus together. There was no significant difference (p = 0.05) in T2 relaxation of the 40% and 70%. The phantoms are stable, robust, and reproducible.

Applications of diesel electric power to railways

Tue, 01 Jan 1935 00:00:00 GMT

Applications of diesel electric power to railways Cook, J. T. (Joseph T.) Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1935; Includes bibliographical references (leaf [78]).

A language house cluster for Mount Holyoke College

Tue, 01 Jan 1963 00:00:00 GMT

A language house cluster for Mount Holyoke College Russell, Samuel L. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1963; Includes bibliographical references (leaf 22).

Methods of nomographic disjunction

Wed, 01 Jan 1958 00:00:00 GMT

Methods of nomographic disjunction Muckenhoupt, Joanna. Thesis: B.S., Massachusetts Institute of Technology, Department of Mathematics, 1958; MIT copy bound with: The fixed point theorem in various spaces / by Jerome Paul Levine [1958]; Includes bibliographical references (leaf 36).

Origin to destination unreliability in rail freight transportation.

Sat, 01 Jan 1972 00:00:00 GMT

Origin to destination unreliability in rail freight transportation. Martland, Carl D. (Carl Douglas) Thesis: Civ. E., Massachusetts Institute of Technology, Department of Civil Engineering, 1972; Bibliography: leaves 143-145.

Design and development of an apparatus to study the flow-induced forces in a poppet-type flow valve

Sat, 01 Jan 1955 00:00:00 GMT

Design and development of an apparatus to study the flow-induced forces in a poppet-type flow valve Stone, James Alexander. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1955; Bibliography: leaf 31.

A nonlinear mathematical model of respiratory sinus arrythmia

Fri, 01 Jan 1993 00:00:00 GMT

A nonlinear mathematical model of respiratory sinus arrythmia Tedrow, Usha B. (Usha Beth) Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1993; Includes bibliographical references (leaf 62-63).

A method for calculating the weak field metric and equations of motion for a plasma.

Sat, 01 Jan 1972 00:00:00 GMT

A method for calculating the weak field metric and equations of motion for a plasma. Knauer, James Philip. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1972; Bibliography: leaf 27.

Hierarchical error correcting cassette file system

Sat, 01 Jan 1977 00:00:00 GMT

Hierarchical error correcting cassette file system Siggia, Alan Dale. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1977; Includes bibliographical references.

The Influence of Defects on the Vibrational and Electronic Properties of the Quasi 1D van der Waals Magnet CrSBr

Sun, 01 May 2022 00:00:00 GMT

The Influence of Defects on the Vibrational and Electronic Properties of the Quasi 1D van der Waals Magnet CrSBr Torres, Kierstin The emergence of 2D semiconducting magnets offers exciting potential to explore low dimensional magnetism, magneto-electronic coupling, and the design of novel magnetic phases through defect engineering. The 2D semiconducting antiferromagnet CrSBr has generated recent attention because of its correlated magnetic, optical, and electronic properties, air stability, and quasi-1D electronic structure. In this thesis, we implement resonant Raman spectroscopy to explore the electron-phonon interactions in CrSBr. We find that the electron-phonon coupling is strongly polarized along the b-crystallographic axis, confirming the presence of a quasi-1D electronic structure. We then investigate the influence of defects on the vibrational and electronic properties of CrSBr through resonant Raman spectroscopy of flakes irradiated with helium ions. The defective Raman spectra of CrSBr can be understood through the phonon confinement model, and we identify the emergence of two defect modes. These modes are also strongly polarized along the b-axis and are enhanced by resonant Raman spectroscopy. Remarkably, we find that the polarization response is preserved even at high defect concentrations, indicating that the electronic structure of CrSBr is highly robust. Finally, we exfoliate four additional air-stable 2D magnets with a MOCl (M = Ti, V, Fe, Cr) composition, which we believe may also have similar advantageous properties as CrSBr.

Informing Data-Driven Recyclable Aluminum Design with Phase Constraints

Sun, 01 May 2022 00:00:00 GMT

Informing Data-Driven Recyclable Aluminum Design with Phase Constraints Ahrens, Jacqueline The design of new aluminum alloys for recycling constitutes a large, multi-dimensional composition space. Within a Bayesian optimization blending model, phase or composition constraints are necessary to narrow the design space within and focus on regions that may contain viable alloys. This thesis focuses on the 6xxx-series system through a broad dataset comprising all known Al-Mg-Si composition and thermodynamic calculations of individual compositions. Explicit matrix phase constraints are not superior to basic Al composition constraints within lean alloys. To suppress detrimental 𝛽-AlFeSi constituent phases and promote strengthening 𝑀𝑔₂𝑆𝑖 intermetallic phases, ratios of Fe/Mn=1 and Mg/Si=1.73 are sufficient. Equilibrium and Scheil calculations of commercial compositions show non-linear regimes where the Fe/Mn=1 rule may be too conservative and point towards ways to expand the amount of Fe that recycled aluminum can accommodate.

Interpretable Supervised Learning and Graph-Based Optimization for Glycan-Lectin Binding

Sun, 01 May 2022 00:00:00 GMT

Interpretable Supervised Learning and Graph-Based Optimization for Glycan-Lectin Binding An, Joyce Non-linear biological macromolecules, such as glycans, participate in a wide range of key structural, metabolic, and regulatory functions in all living organisms. Many of these essential roles involve interactions with glycan-binding proteins called lectins. As a result, there is particular interest in the design of highly specific glycan binders to critical lectins such as dendritic cell-specific ICAM-grabbing non-integrin (DC-SIGN). However, insufficient knowledge of the binding specificity of lectins, combined with the enormous structural complexity of glycans that range from linear to highly branched, serve as a barrier to the rational computational and experimental design of effective glycan binders. Here, using mammalian microarray data from the Consortium of Functional Glycomics, we predict glycan-lectin binding affinity and lectin specificity using an interpretable graph-based supervised learning framework. For the first time, we uncovered both monomers and motifs more precise than the monomer unit critical for lectin specificity. Furthermore, we developed a general graph-based optimization framework for macromolecules that employs the trained regression model ensembles to design glycans with high binding strength, low uncertainty in binding strength prediction, and low probability of human immunogenicity. Our work provides a general framework for iterative, chemistry-informed and topology-agnostic design in the macromolecular chemical space.

Supramolecular Nanostructures as Support Materials for Gold Nanoparticle Catalysts

Sun, 01 May 2022 00:00:00 GMT

Supramolecular Nanostructures as Support Materials for Gold Nanoparticle Catalysts Tai, Kiera Y. The high catalytic activity of gold nanoparticles (AuNPs) has led to their use in a variety of industrially-relevant reactions, such as low-temperature CO-oxidation and selective alcohol oxidation. Most current research focuses on heterogenous gold catalysis, with metal oxides being the most commonly employed support material for AuNPs. However, metal oxides are challenging to evenly distribute in solution and intrinsically difficult to modify. Molecular self-assembly provides a novel route to synthesize AuNP support materials, offering precise control over spatial arrangements and tunable surface chemistries. A particularly promising self-assembled molecule is the aramid amphiphile (AA), which overcomes the typical mechanical fragility of self-assembled structures by incorporating a Kevlar-inspired domain into its molecu- lar structure. In this work, we present a cysteine-functionalized aramid amphiphile platform (CysAA) for AuNP stabilization, which exhibits favorable surface chemical affinity to gold. We show that AuNPs are anchored on the surface of CysAA which can be evenly dispersed in solution, enabling quasi-homogeneous catalysis in aque- ous conditions. Furthermore, the high aspect-ratio of these nanostructures allows for the recovery and recycling of AuNPs from solution by simple filtration. Using the model reduction reaction of 4-nitrophenol, we demonstrate the catalytic activity and recyclability of this AuNP-CysAA catalyst.

Characterization of the Effects of Thickness and Composition in Current Induced Phase Change in Sb₂Se₃ and Sb₂S₃

Thu, 01 Feb 2024 00:00:00 GMT

Characterization of the Effects of Thickness and Composition in Current Induced Phase Change in Sb₂Se₃ and Sb₂S₃ Bolzan, Maximilian Adriano Phase-change memory is a promising new field for the world of memory storage, but current limitations such as slower switching speeds than current forms memory like random-access memory (RAM) and flash memory, have made the implementation of phase-change memory infeasible. Antimony triselenide (Sb₂Se₃) and antimony trisulfide (Sb₂S₃) are two materials that have already been investigated for their applications in solar cells, thermal storage, and other photovoltaic . Samples of Sb₂Se₃ and Sb₂S₃ were produced at two varying thicknesses each, 30 nm and 200 nm in order to determine the optimal combination of thickness and composition. Optimal performance was determined by the endurance of the samples when undergoing current induced phase changes and the difficulty in switching between crystalline and amorphous states. Through a combination of optical microscopy, Raman spectroscopy, and scanning electron microscopy, the samples were characterized and analyzed for their performance in phase cycling. The 200 nm samples and Sb₂Se₃ samples generally demonstrated a greater performance in endurance and lack of dewetting after phase cycling.

Photometric Explorations of Volatile Shifts on Pluto’s Surface

Thu, 01 Feb 2024 00:00:00 GMT

Photometric Explorations of Volatile Shifts on Pluto’s Surface McLellan-Cassivi, Claire Pluto was observed over the course of three months with the goal of generating light curves to determine if volatile transport had occurred since the New Horizons Mission in 2015. Pluto’s surface is primarily made up of volatile ices, which are thought to migrate as Pluto’s seasons change. Further understanding of how these volatiles migrate across Pluto could further constrain models of Pluto’s atmosphere. The light curves generated in this project were compared to pre-New Horizons light curves to determine any volatile transport. These comparisons provide evidence of possible migration of ice in the Tombaugh Regio, which could be useful in further atmospheric research. Further observations with higher exposure times are needed to determine if volatile transport has happened in other major regions of Pluto.

The determination of the change in operating expenses of the Old Colony Branch of the New York, New Haven & Hartford Railroad Company after elimination of certain trains from the present schedule

Thu, 01 Jan 1948 00:00:00 GMT

The determination of the change in operating expenses of the Old Colony Branch of the New York, New Haven & Hartford Railroad Company after elimination of certain trains from the present schedule McGowan, Frank M.; Yurgelun, Albert A. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1948

Detection of rapid fluctuations in the earth's magnetic field.

Mon, 01 Jan 1973 00:00:00 GMT

Detection of rapid fluctuations in the earth's magnetic field. Gordon, Michael Jerome Valovis. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1973; Diagrs. and table numbered as preceding leaves (5 leaves).

A modern empire building, Ralph Budd

Sat, 01 Jan 1955 00:00:00 GMT

A modern empire building, Ralph Budd Barriger, Stanley Huntington. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1955; Includes bibliographical references (leaves 234-238).

The effect of inlet port elbows on intake of the internal combustion engine

Sun, 01 Jan 1939 00:00:00 GMT

The effect of inlet port elbows on intake of the internal combustion engine Estes, George Lawton.; Hawkes, James Ellison. Thesis: B.S., Massachusetts Institute of Technology, Department of Aeronautical Engineering, 1939; Includes bibliographical references.

Heavy duty mack truck styling

Sat, 01 Jan 1949 00:00:00 GMT

Heavy duty mack truck styling Jordan, Chuck, 1927-2010. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1949; Index contains numerous pamphlets.; Includes bibliographies.

The element distribution of cosmic rays produced by white dwarf spinars.

Sat, 01 Jan 1972 00:00:00 GMT

The element distribution of cosmic rays produced by white dwarf spinars. Perrenod, Stephen Charles. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1972; Bibliography: leaves 55-56.

Design of embankments on soft soil.

Sat, 01 Jan 1972 00:00:00 GMT

Design of embankments on soft soil. Kirby, Robert Charles. Thesis: Civ. E., Massachusetts Institute of Technology, Department of Civil Engineering, 1972; Bibliography: leaves 68-69.

Determination of the virtual mass of the Akron due to the potential flow of air about it

Fri, 01 Jan 1932 00:00:00 GMT

Determination of the virtual mass of the Akron due to the potential flow of air about it Ebel, Isabel C. Thesis: B.S., Massachusetts Institute of Technology, Department of Aeronautical Engineering, 1932; Includes bibliographical references (leaf 24).

Characteristics and succession of the fossil faunas of the middle devonian (Hamilton Group) at Eighteen Mile Creek, New York

Wed, 01 Jan 1896 00:00:00 GMT

Characteristics and succession of the fossil faunas of the middle devonian (Hamilton Group) at Eighteen Mile Creek, New York Grabau, Amadeus W. (Amadeus William), 1870-1946. Thesis: B.S., Massachusetts Institute of Technology, Department of Geology, 1896

Development of a comparative Markov model for ship overhaul policies

Sat, 01 Jan 1972 00:00:00 GMT

Development of a comparative Markov model for ship overhaul policies Eldred, William Alexander. Thesis: Ocean E., Massachusetts Institute of Technology, Department of Ocean Engineering, 1972; Includes bibliographical references (leaves 78-80).

A design for a recinforced concrete warehouse

Mon, 01 Jan 1923 00:00:00 GMT

A design for a recinforced concrete warehouse Hails, Thomas Jefferson. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil and Sanitary Engineering, 1923

A educational survey of 2.01.

Sat, 01 Jan 1972 00:00:00 GMT

A educational survey of 2.01. Kirkpatrick, Allan. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1972; Bibliography: leaf 84.

PDP/11 LISP and its use to teach automatic computation concepts.

Sat, 01 Jan 1972 00:00:00 GMT

PDP/11 LISP and its use to teach automatic computation concepts. King, Richard Michael. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1972; Title and part of text within red line borders.; Includes bibliographical references.

Improving the efficiency of high pressure homogenizers for cell disruption application

Tue, 01 Jan 1985 00:00:00 GMT

Improving the efficiency of high pressure homogenizers for cell disruption application Masucci, Stephen Francis. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1985; Bibliography: leaves 96-97.

Characterization and Modeling of the Human Mouth Space for the Informed Design of Intraoral Wearable Human-Computer Interfaces

Thu, 01 Jun 2023 00:00:00 GMT

Characterization and Modeling of the Human Mouth Space for the Informed Design of Intraoral Wearable Human-Computer Interfaces Warneryd, Carolina S. This project involved the development of a model for the human oral cavity to aid in the design of intraoral wearable human-computer interfaces, which have great potential for impact especially in the assistive technology domain. The model is intended to provide a preliminary look at the design space of an individual’s mouth, predicting key volumes, dimensions, and biomechanical properties based on a few easily obtainable exterior measurements. The outputs of the model can inform the physical and material properties of the intraoral wearable design, saving the expense, difficulty, and intrusiveness of obtaining a precise mouth scan during the prototyping phase. Initial evaluation of the model showed that it predicted geometries with an average of 20% error. Many outputs of the model still need to be validated and improved through human subject studies. Once the model is refined to estimate mouth geometry within reasonable accuracy, it will be connected to CAD software, creating a 3D mouth space simulation that enhances the intraoral wearable design process.

“Do you collect data to give to the university or do you do the work to benefit people?”: Indigenous Data Sovereignty in Environmental Contexts

Thu, 01 Jun 2023 00:00:00 GMT

“Do you collect data to give to the university or do you do the work to benefit people?”: Indigenous Data Sovereignty in Environmental Contexts Doğan, Amelia Lee Indigenous data sovereignty is the right of tribes to own, control, and apply data about their lands, peoples, and resources. Although grassroots and academic definitions of Indigenous data sovereignty encompass the idea of tribal authority over environmental data, few sources provide case studies or theoretical background on how Indigenous data sovereignty can be operationalized in an environmental context. Through interviews with 3 Indigenous environmental activists and practitioners and an environmental case study with the Penobscot Nation, I explore how Indigenous data sovereignty is currently practiced in the environmental area. I analyze the findings using the CARE principles, a set of Indigenous data sovereignty and governance principles. From this, I find further environmental case studies for the development of environmental specific Indigenous data sovereignty guidelines are necessary. Additionally, I advocate for further detailing of rightsholder and stakeholder obligations in the CARE principles for better collaborative research.

The synthesis of substituted benzophenones and benzhydrols

Fri, 01 Jan 1960 00:00:00 GMT

The synthesis of substituted benzophenones and benzhydrols Kerber, Robert Charles, 1938- Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1960; Includes bibliographical references (leaf 15).

Use of attitude stick force cues to improve velocity control system performance.

Sat, 01 Jan 1972 00:00:00 GMT

Use of attitude stick force cues to improve velocity control system performance. Elberfeld, Lawrence George. Thesis: E.A.A., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 1972; Includes bibliographical references.

The pallet - an important piece of industry's materials handling equipment

Wed, 01 Jan 1947 00:00:00 GMT

The pallet - an important piece of industry's materials handling equipment Adams, Frederick P. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1947; Bibliography: leaves 100-102.

Development of a radiant-heat furnace for the study of chemical reactions

Wed, 01 Jan 1936 00:00:00 GMT

Development of a radiant-heat furnace for the study of chemical reactions Webb, George B. (George Barlow) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1936

Effect of vapor velocity in rectification / by Albert James Ullman.

Wed, 01 Jan 1936 00:00:00 GMT

Effect of vapor velocity in rectification / by Albert James Ullman. Ullman, Albert James. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1936; Includes bibliographical references (leaf 38).

Operating characteristics of an impingement type dust separator,

Tue, 01 Jan 1946 00:00:00 GMT

Operating characteristics of an impingement type dust separator, Almeida, Americo.; Redlien, William. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1946; Bibliography: leaf 33.

Bail bondsmen.

Sat, 01 Jan 1972 00:00:00 GMT

Bail bondsmen. Edwards, Joseph Albert. Thesis: B.S., Massachusetts Institute of Technology, Department of Political Science, 1972; Bibliography: leaf 58.

Exploring the Effect of Irradiation Time on the Damping of Surface Acoustic Waves

Fri, 01 Sep 2023 00:00:00 GMT

Exploring the Effect of Irradiation Time on the Damping of Surface Acoustic Waves Belleque, Bethany Anne Finding relationships between material structure and properties is a key discipline of materials science. Many methods have been used to examine material properties, including transient grating spectroscopy (TGS). These properties were used to probe several scales of structure, and TGS has been applied in this way to solve several challenges. This thesis explores the details of the TGS signal itself, and how the property of irradiation time affects different qualities of the signal. In particular, the acoustic damping parameter is scrutinized in relation to the irradiation time of the samples from Byron Nuclear Generating Station. The trend was found to be similar to that of other material properties when compared with irradiation time, denoting the creation and subsequent clustering of defects. Further research with higher granularity into the relationship is suggested in order to further the development of nondestructive evaluation techniques.

Hysteresis of nitrocellulos films

Wed, 01 Jan 1936 00:00:00 GMT

Hysteresis of nitrocellulos films Terry, Thomas Alexander, 1885-1963. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1936; Includes bibliographical references (leaves 55-56).

A study of captive finance companies

Thu, 01 Jan 1959 00:00:00 GMT

A study of captive finance companies Leahy, John Paul. Thesis: B.S., Massachusetts Institute of Technology, School of Industrial Management, 1959; Includes bibliographical references.

Study for parking garage on M I T property

Mon, 01 Jan 1951 00:00:00 GMT

Study for parking garage on M I T property Sandsto, Bjorn. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1951; Bibliography: leaf [40].

Superplasticity in lead-tin alloys.

Sat, 01 Jan 1966 00:00:00 GMT

Superplasticity in lead-tin alloys. Cannon, Rowland M., 1914-2013. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1966; Bibliography: leaves 39-40.

Applications of computer-aided circuit design and analysis.

Mon, 01 Jan 1968 00:00:00 GMT

Applications of computer-aided circuit design and analysis. Ohm, William Henry. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1968; Leaves 29-50 folded and inserted in pocket on back cover.; Bibliography: leaf 51.

The history and development of locomotive feed water heaters

Sat, 01 Jan 1927 00:00:00 GMT

The history and development of locomotive feed water heaters Hopkins, Irving L. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1927; Includes bibliographical references (leaf [49]).

Effects of XR Technology on Motor Learning in Fencing

Thu, 01 Jun 2023 00:00:00 GMT

Effects of XR Technology on Motor Learning in Fencing Ryu, Enya Increasing benefits of utilizing immersive training environments for sports like basketball and baseball inspired a fencing coach to inquire its role in enhancing traditional coaching methods. This study investigates the potential of immersive training environments in augmenting traditional fencing pedagogy, which commonly involves mimicry of in-person mentors or videos and practice through recollection. Thirty participants with no prior fencing experience were taught the advance-jump-lunge sequence in various extended reality environments, using two common coaching styles: teaching individual sequence elements first and teaching the complete movement before its deconstruction. Initial findings suggest that subjects who learned individual components first generally demonstrated higher learning levels, supporting the part-task training strategy in fencing instruction, although no significant influence of learning environment type on learning levels was observed. This study provides valuable insights into fencing pedagogy and offers a roadmap for future research, which may include a detailed investigation of kinematic properties or additional data collection to track long-term effects and the learning trajectory of alternate movements.

Sewage disposal

Mon, 01 Jan 1906 00:00:00 GMT

Sewage disposal Harvey, Herbert. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1906

Application of store-door delivery to carload freight

Mon, 01 Jan 1934 00:00:00 GMT

Application of store-door delivery to carload freight Roulston, Robert. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1934

The metallographic examination of cast, annealed, and age-hardened high-silicon monel metals

Mon, 01 Jan 1940 00:00:00 GMT

The metallographic examination of cast, annealed, and age-hardened high-silicon monel metals Stroke, Frederick G. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1940; Includes bibliographical references (leaf 24).

Progressive speed trials of steam yacht "Kaleda"

Sun, 01 Jan 1899 00:00:00 GMT

Progressive speed trials of steam yacht "Kaleda" Newell, William Stark, 1878-1954. Thesis: B.S., Massachusetts Institute of Technology, Department of Naval Architecture and Marine Engineering, 1899

Photoexcitation of nuclear isomers

Sat, 01 Jan 1955 00:00:00 GMT

Photoexcitation of nuclear isomers Dupree, Thomas H. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1955; Bibliography: leaf 13.

Centrifugal refrigeration with ammonia

Wed, 01 Jan 1947 00:00:00 GMT

Centrifugal refrigeration with ammonia Schmitz, Andrew J. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1947; Bibliography: leaf 47.

Design and Construction of a Fully Submerged Hydrofoil Drone Boat

Thu, 01 Jun 2023 00:00:00 GMT

Design and Construction of a Fully Submerged Hydrofoil Drone Boat Poss, Jonhenry A remotely operated hydrofoil watercraft was designed and built as a test platform for active electromechanical controls as applied to fully submerged hydrofoils in a form just small and lightweight enough to be tested safely without a human physically at the controls. The goal was to build a watercraft sufficiently large and scalable enough that results obtained from it could be realistically applied to personal hydrofoil vehicles without the danger of a human in the vessel during testing. The project also explores roll dynamics while not on foil. The vessel was built to a length of 1.53 meters with 0.34-meter masts with servo controlled forward foil and aft flippers. The hull is constructed from lightweight 1/8in plywood with a fiberglass and epoxy composite skin. The foils and masts were 3D printed at low density and skinned with fiberglass. These structures have mechanically performed well, surviving both the hydrodynamic forces and repeated crashes. The foils were designed such that the craft would reach foiling speeds at zero degrees pitch at 4 m/s at a mass of 13.1 kg distributed 70% to the aft foil and 30% to the forward foil. The final weight was 14.1 kg. Working towards digital control, the watercraft is equipped with two ultrasonic sensors for height sensing, with room for expansion, and an inertial measurement unit.

Principles of Laser Alignment in Atomic Force Microscopy and its Potential Application for Nanoscale 3D Printing

Thu, 01 Jun 2023 00:00:00 GMT

Principles of Laser Alignment in Atomic Force Microscopy and its Potential Application for Nanoscale 3D Printing Li, Cong Atomic Force Microscopy (AFM) is a well-established technique that has played a significant role in the characterization of nanoscale structures. While its applications in surface profiling and imaging of nanomaterials are widely recognized, the potential of AFM techniques in 3D printing applications has not been fully explored. In this thesis, we present a detailed process of building a custom Atomic Force Microscope, which has been adapted to an AFM probe with microfluidic channels. The construction process involved building and aligning the optics system, testing the optics sensors, assembling the entire AFM system, creating the user interface, coding, and testing the position controllers. The developed AFM-based 3D printer has immense potential in enabling ultra-high resolution 3D printing, as well as in-situ characterization of the printed structure. In future work, the necessary components would be added to the AFM-based 3D printer to enable precise dispensing of materials through the microfluidic channels within the probe, making it possible to print structures with unprecedented precision. The potential of this technology in transforming the way nanoscale 3D printing is done cannot be overstated, and further testing and development would be required to establish its viability in practical applications.

Synthesis and Reactivity of Anthracene-Based Molecular Precursors for Low-Valent Boron Species

Thu, 01 Jun 2023 00:00:00 GMT

Synthesis and Reactivity of Anthracene-Based Molecular Precursors for Low-Valent Boron Species Sukhram, Dion S. The study of compounds containing elusive main group multiple bonds has long been a topic of immense interest. Today, it remains an attractive path towards unlocking new reactivity and developing a complete empirical understanding of chemical bonding. However, due in large part to a lack of suitable synthetic methodologies, the chemistry of numerous desirable functionalities remains poorly accessible. Herein, we report the synthesis of the first series of dibenzo-7-boranorbornadienes, or 9,10-bridged boron anthracene (RBA, A = anthracene or C₁₄H₁₀) compounds, and their unique properties and reactivity. Oxidation of ⁱPr₂NBA with an amine oxide was found to lead to the selective formation of the bicyclic borinate ester ⁱPr₂NBOA, an easily isolable solid that unimolecularly fragments to ⁱPr₂NBO + A upon heating to moderate temperatures in solution. This rare free, monomeric oxoborane has been demonstrated to undergo cycloadditions with a number of organic substrates and efforts to expand both the scope of derivatives and reactivity are underway. The possibility to access species containing highly unstable boron-pnictogen triple bonds has also been explored via the synthesis of the azidoborane trimer (N₃BA)₃ and cyclic(alkyl)(amino)carbene (CAAC) stabilized boraphosphaketene ᵉᵗCAAC·ABPCO. Preliminary and ongoing reactivity studies are discussed.

Leidenfrost Drop Ratchet Impact Dynamics

Thu, 01 Jun 2023 00:00:00 GMT

Leidenfrost Drop Ratchet Impact Dynamics Ramesh, Nathan A drop deposited on a sufficiently hot substrate generates its own vapor cushion preventing contact with the surface. This vapor layer is responsible for the low friction and long lifetime of the drop. Falling water droplets will even bounce on their own vapor layer. By varying the geometry of a surface at the micro-scale, it is possible to control the movement of impacting droplets in this Leidenfrost state. We propose a model for the behavior of droplets impacting a micro scale ratchet structure. In particular, we theorize that surface roughness can lead to an inconsistent vapor layer, allowing for propulsion resulting from contact boiling. Additionally, pressure differences in the vapor layer can drive a convective vapor flow that can drag the drop along. In this study, we examine the horizontal velocity of water dropped on a ratchet surface with varying temperature, impact velocity, and ratchet geometry. We provide a new explanation—involving both propulsion from contact boiling as well as convective vapor flow—for why droplets move in the direction they do.

Base and Manifold Casting of the Atlantic “Make-and-Break” Marine Engine

Thu, 01 Jun 2023 00:00:00 GMT

Base and Manifold Casting of the Atlantic “Make-and-Break” Marine Engine Scherer, Emily The Atlantic Marine Engine, manufactured by the Lunenburg Foundry in Nova Scotia, was a revolutionary two stroke combustion engine that transformed the fishing industry on the east coast in the early 20th century. A replica project of this engine was initiated in 2016 in Pappalardo Lab at MIT by a group of students using modern machining and modeling techniques to understand how parts for this particular engine were cast more than 100 years ago. Students have been fabricating parts for the engine ever since, and as of Fall 2022, three components were left to complete. This thesis covers the casting and machining of two of these three parts: the upper base and the manifold. This thesis will explain how the patterns and cores were made, pour orientations, and machining techniques.

A Low Cost Power Assist for Active Wheelchair Users

Thu, 01 Jun 2023 00:00:00 GMT

A Low Cost Power Assist for Active Wheelchair Users Fan, Max Wheelchair power assists are devices that a wheelchair user may retrofit onto their wheelchair to increase their range, speed, and power. Users of these devices may already have the ability to propel themselves manually, but their mobility is further enhanced with these devices. This is particularly true for “active” wheelchair users, who use wheelchairs specially designed for an active, physical lifestyle. However, commercial power assists often cost thousands of dollars, which can be a significant financial barrier for wheelchair users who cannot get insurance to cover the cost. For this reason, I have partnered with a permanent wheelchair user to create and test a low cost power assist, which we call the “Tailwind,” that wheelchair users can build with minimal tools. By enabling more wheelchair users to add a power assist to their wheelchair, we intend to facilitate exercise and independence for wheelchair users who may feel otherwise restricted in range, speed, or power. Based on the prototype, I estimate the total cost to be less than $450, which is an order of magnitude less than commercially available power assists. I estimate the range to be 11 miles on smooth terrain such as concrete and 4.3 miles on rough terrain such as grass, and I estimate the maximum speed to be 9.7 mph. As for power, I estimate that the Tailwind can climb a slope of 7.4° (13% grade) on its own power and at least 15° (27% grade) when the user is also manually pushing theirself. Additionally, the Tailwind has a lift mechanism that allows the user to lift the Tailwind’s wheel off the ground when not in use. Lifting the Tailwind eliminates its rolling resistance and is a feature that does not appear on any commercial power assists as far as I am aware.

The Rowland disk.

Thu, 01 Jan 1970 00:00:00 GMT

The Rowland disk. Huber, Alan Curtis. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1970; Bibliography: leaf [21].

An investigation into the utilization of secondary images in classroom development of reading comprehension.

Mon, 01 Jan 1973 00:00:00 GMT

An investigation into the utilization of secondary images in classroom development of reading comprehension. Kollisch, Donald Owen. Thesis: B.S., Massachusetts Institute of Technology, Department of Humanities, 1973; Bibliography: leaf 41.

A study of motor truck store door pickup and delivery charges

Wed, 01 Jan 1936 00:00:00 GMT

A study of motor truck store door pickup and delivery charges Gardiner, John Dick.; Danforth, Francis Jenkins.; Gorham, Marvine. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1936; Includes bibliographical references (leaf 142).

Novel Embroidered Actuator Fabrication and Design Optimization

Thu, 01 Jun 2023 00:00:00 GMT

Novel Embroidered Actuator Fabrication and Design Optimization Waft, Sylvia Elise McKibben actuators have extensive applications in soft robotics and wearables; however, traditional manufacturing processes limit their ability to tailor design parameters to specific applications. This thesis explores a novel fabrication method for these actuators: using an embroidery machine to create the ‘outer mesh,’ thus allowing for variation of backing material and embroidery pattern. Having tested and iterated through six assembly processes, the most reliable method is presented, beginning with digital embroidery pattern creation and concluding with the final actuator assembly. Additionally, the actuators are characterized to illustrate how varying the design parameters affects performance. The effect of pressure on actuator movement is explored, and it can be seen that as pressure increases, actuator curvature increases. Out of the three embroidery backing materials explored – felt, cotton, and polyester – felt had the greatest curvature until 24psi, beyond which polyester surpasses it. This work also shows that the addition of embroidery onto the backing material decreases curvature and that varying the embroidery patterns results in different decreases. The resulting curvatures in all these experiments demonstrate how the response of embroidered actuators can be tailored to meet the design requirements for specific uses. Finally, different applications of these actuators are explored, and a robotic hand for which the actuators have been used as fingers is shown.

NITE–Processed SiC/SiC Ceramic Composites in Liquid Sandwich Vacuum Vessel

Thu, 01 Jun 2023 00:00:00 GMT

NITE–Processed SiC/SiC Ceramic Composites in Liquid Sandwich Vacuum Vessel Lin, Yong Jie In 2022, the Biden-Harris Administration released their Bold Decadal Vision for Com-mercial Fusion Energy [1]. The plan called for the rapid development of robust and economical commercial fusion technology. This thesis focuses on the vacuum ves-sels (VVs) surrounding the plasma in an ARC-class fusion tokamak. VVs require signiﬁcant development to go from their current state of the art in research-scale, non-breakeven fusion devices to the much larger, thinner, and robust VVs that com-mercial fusion tokamaks will require. Conventional research tokamaks have VVs made of thick-walled steel or superalloys so that the device can resist the large disruption forces that occur when the plasma quenches. Commercial-scale VVs need to let ther-mal energy and neutrons through to the tritium breeding blanket surrounding the plasma while maintaining a vacuum. Thick-walled VVs hinder eﬃcient heat transfer and absorb neutrons. A new "liquid sandwich vacuum vessel" (LSVV) design proposes to use thin walls of silicon carbide ceramic composite (SiC/SiC) surrounding a layer of liquid lead. Because liquid lead is much more electrically conductive than SiC/SiC, the liquid lead absorbs disruption-induced currents and the resulting forces. This enables the use of a thin-walled VV to promote heat transfer while still resisting dis-ruption damage. The SiC/SiC ceramic composite that the LSVV development team is most interested in is made using the Nano-Inﬁltration Transient Eutectic (NITE) process, which allows for very low porosity composites to be achieved. NITE-type SiC/SiC samples were characterized experimentally. Then, COMSOL simulations were done using a combination of literature data and the novel property data ob-tained in this work to show how an LSVV compares to conventional VV designs. Simulations show that the LSVV design achieves a 32.5% increase in the modiﬁed Carnot eﬃciency and reduces the maximum Von Mises stress in the VV by an order of magnitude, while keeping a safety factor of 1.268, as compared to a conventional solid-walled VV made from EUROFER97.

Analysis of the Effects of Basic Printer Settings on PLA 3D Prints

Thu, 01 Jun 2023 00:00:00 GMT

Analysis of the Effects of Basic Printer Settings on PLA 3D Prints Morch, Nine Desktop-size 3D printers are capable of producing functional prints for an extremely wide variety of designs, but many hobbyist printers still struggle with print defects such as warping, stringing, and blobbing appearing on their prints. There are many existing recommendations for dealing with any of these problems, but some of those recommendations involve materials or resources that hobbyist printers may not have access to, such as printer-specific filament or a heated environment. This thesis investigates how problems such as warping, blobbing and stringing can be affected by changing basic print settings that should be available on all slicing softwares and printers: nozzle temperature, bed temperature, flow rate, and print speed. Blobbing can be caused by the flow rate being too high or the print speed being too low, and is also present around the corners of parts when the nozzle or bed temperatures are too high. Stringing is very print-path-dependent, but may be lessened by lowering the nozzle temperature. Warping is strongly a function of both nozzle and bed temperature, and increasing temperatures will decrease warping. However, increasing bed temperature too high will start to cause uneven cooling, and the bottom of the part will shrink compared to its nominal dimension. The experiments conducted for this thesis find that starting a PLA print with default values of 200°C nozzle temperature, 60°C bed temperature, 100% flow rate and 50 mm/s print speed, then slowly incrementing the values to fix the most evident problems, will provide the best quality print.

Design of a Modular Offshore Autonomous Underwater Vehicle Servicing Platform

Thu, 01 Jun 2023 00:00:00 GMT

Design of a Modular Offshore Autonomous Underwater Vehicle Servicing Platform Woodcock, Luke Deep-sea scientific data is often challenging and expensive to collect because the primary method of acquisition, Autonomous Underwater Vehicles (AUVs), are limited by battery capacity and must be charged and serviced by crewed support ships. The Platform for Expanding AUV exploRation to Longer ranges (PEARL) hopes to solve this through an autonomous offshore AUV-servicing platform that can charge AUVs, collect their data, and upload it to the internet via modern satellite terminals. The second-generation PEARL prototype (PEARL v2) has been tested and developed on for two years and its design weaknesses are showing. This thesis details the design and manufacturing of a third-generation PEARL prototype (PEARL v3) that upgrades the structural and mechanical systems while retaining the size, profile, and core electronics of PEARL v2. The design process examined PEARL v2’s hardware and how it was used to identify points of improvement, such as its inability to easily be launched with a boat ramp, or its susceptibility to corrosion due to fastener choice, and addressed them. The redesign also enables PEARL to achieve the project’s new objectives. PEARL v3’s design significantly improves traversal capabilities which will support a robust autonomous navigation and collision avoidance system. The design also features a modular architecture that will allow PEARL v3 to be re-equipped with various mission packages for different tasks. PEARL v3 will serve as the projects structural base and foundation for future development and testing.

Exploration and Design of a Magnetic Levitation System

Thu, 01 Jun 2023 00:00:00 GMT

Exploration and Design of a Magnetic Levitation System Vu, Kiet The project focuses on exploring the inner workings of a magnetic levitation system: a commercial levitating moon-lamp device. This device is able to levitate the floating lamp from the bottom and is stable when aligned correctly. The objective is to investigate how this device operates. A commercial device is purchased and disassembled to investigate the inner-working of the device. Theoretical models and simulations are used to explain its behavior. For the second part of this project, a new device is then designed and built, featuring custom control circuits, driver and mechanical fixture. This setup is able to achieve levitation indefinitely and handle light disturbance coming from the user. There are a couple extensions to the project that can be explored, including improvement in cooling and electronics design, better analysis framework, and implementation of digital control system.

Characterizing The Response Of A Force Feedback Joystick

Thu, 01 Jun 2023 00:00:00 GMT

Characterizing The Response Of A Force Feedback Joystick Noguera, Joshua The 77 Lab has created a joystick capable of force feedback to be part of their excavator simulator. Using the joystick, they will study the effects of force feedback on novice and experienced heavy machinery users and with the goal of understanding how force feedback can affect learning quality and speed. To create this force feedback and Proportional Derivative controller was selected. By sweeping control loop parameters of a PD controller, the stability region for this joystick was found. In addition further experiments were conducted to characterize the effects of control loop frequency, set position, and springs. Ultimately it was found that the system preforms significantly better at higher control loop frequencies near 600Hz when compared to 300Hz, it has asymmetrical performance in specific directions, and that springs provide a significant improvement towards the stability of the system.

Characterizing Failure Modes in Continuous Flow Microfluidic Pumps

Thu, 01 Jun 2023 00:00:00 GMT

Characterizing Failure Modes in Continuous Flow Microfluidic Pumps Jia, Delace Microphysiological systems provide novel platforms for drug testing and therapeutic target discovery, through their three-dimensional morphologies that mimic specific tissues and organs. In concurrence with these systems, microfluidic channels allow for a sufficient supply of nutrients to the cell culture; by creating pressure gradients across the system, they allow for fluid flow through the tissue medium. A microfluidic pump, Microheart, for continuous flow through microphysiological systems was presented in Offeddu, 2021. The design introduced a novel, low-cost method of delivering cell culture media at low flow rates. While the Microheart pumps in practice have qualitatively provided an indication of media flow through microphysiological systems, the yield rate of production, and efficacy of their function have not been fully characterized. The following study explores the potential failure modes of the Microheart pump, and characterizes the pump consistency over the standard time of function with cell cultures.

Thermal Analysis of Indirect Liquid Cooling for the Navy integrated Power Electronics Building Block

Thu, 01 Jun 2023 00:00:00 GMT

Thermal Analysis of Indirect Liquid Cooling for the Navy integrated Power Electronics Building Block Hernandez, David E. The development of the Navy integrated Power and Energy Corridor (NiPEC) involves the deployment of modular, self-contained universal converter units known as the integrated Power Electronics Building Blocks (iPEBB). An iPEBB unit sees primary heat generation through four rows of MOSFET switches and a transformer, which produce 9600W and 1100W of waste heat respectively. In response to the Navy's prohibition of direct liquid cooling, indirect liquid cooling, which sees the iPEBB unit in dry contact with a liquid-cooled cold plate, has been chosen as a potential thermal solution. A half-iPEBB thermal model was created and tested in steady state using computational fluid and thermal simulation. The chosen cold plate design using a flow rate of 8.4 gpm and inlet temperature of 25°C was found to reduce MOSFET temperatures to a maximum of 148°C, providing 2°C of margin to operational limits. Heat pipes were explored to counter the high temperatures (>100°C) seen within the ferrite transformer core, resulting in highs between 82°C and 118°C for the range of possible ferrite thermal conductivities. This preliminary analysis confirms the viability of indirect liquid cooling for the MOSFET switches of the iPEBB unit and provides insight into the design of the cooling solution for the transformer core. These findings will inform the requirements of the system-level cooling solution and offer a reference for future experimental testing of the iPEBB unit.

Examination of Lubrication Effects on Fracture Measurements of Hydrogels via Cutting

Thu, 01 Jun 2023 00:00:00 GMT

Examination of Lubrication Effects on Fracture Measurements of Hydrogels via Cutting Garcia, Marcelo Despite cutting being a common process in the fracture of soft materials, there is no well-defined method that can be considered equivalent to some of the more traditional methods of fracture based in tension. A recently developed method by the name of razorblade-initiated fracture testing (RIFT) proves itself to be promising for compression-based fracture quantification, however, the effects of friction that arise in some gels makes it difficult to quantify true cutting fracture energy. We identify that by varying lubrication and rate of cutting, the effects of friction can be minimized, but we are unable to eliminate it entirely. These methods prove effective and can be used to further define the RIFT cutting process

Improved Friction and Dynamics Estimation in Legged Robots

Thu, 01 Jun 2023 00:00:00 GMT

Improved Friction and Dynamics Estimation in Legged Robots Schwendeman, Laura A. Reducing the Sim-to-Real gap between robot simulation and robot performance could lead to improved and more efficient robot design through more accurate controls and design testing in simulation and through more accurate state detection for model-based control architectures. This work built upon current research in the field of robot system dynamics by investigating the effect of using single-layer feed-forward neural nets to model non-linear friction forces and other forms of dynamics that are difficult to account for with traditional robot system identification schemes. Applying the single-layer feed-forward neural nets to system identification data from the dynamic MIT Humanoid and MIT Mini Cheetah robots significantly reduced torque prediction errors. The neural net was able to reduce torque errors by modeling both linear and non-linear effects that could not be easily fit by traditional methods. The results of this paper suggest that using the system identification methodology outlined within could lead to more accurate dynamics modeling, which would assist with closing the Sim-to-Real gap through simulated dynamics with more fidelity and a more robust representation of robot dynamics.

Micro-Architected Carbon Composites

Thu, 01 Jun 2023 00:00:00 GMT

Micro-Architected Carbon Composites Kommalapati, Rishi T. Strong, stiff, and lightweight materials are highly desirable in a variety of industries, but this combination has been unavailable in traditional monolithic materials. High stiffness and low-density micro and nano scale lattices have been produced to meet this desire but are highly brittle and unsuitable for mechanical applications. Three lattice topologies with relative density of 20% were produced in a custom polymer and pyrolyzed into carbon lattices. Two different methods of infiltrating an epoxy matrix into these micro-lattices were tested, reaching fill percentages of ~96% and ~99%. Micro-architected carbon composites were created using the superior infiltration method, and all three stages (polymer, carbon, composite) were compression tested to determine the modulus and strength. The infiltration of the epoxy created an interpenetrating phase composite and mitigated the brittle failure mode of the carbon lattice, increasing its strength, stiffness, and toughness. These results are the first step toward characterizing the mechanical properties of a new class of materials: three-dimensional architected carbon composites.

The Structural Design, Validation, and Fabrication of an Electric Drift Trike

Thu, 01 Jun 2023 00:00:00 GMT

The Structural Design, Validation, and Fabrication of an Electric Drift Trike Ulloa, Gabriella E. Drift trikes are a type of entertainment vehicle used to perform power-on oversteer due to its low coefficient of friction at the rear tires. The design of these vehicles is optimized in such a way that allows drifting while maintaining stability. Characteristics such as frame geometry and weight distribution affect the overall performance of the vehicle. Functional requirements are set in order to ensure drift capability and rider safety. These design criteria inform the overall design and geometry of the frame, and preliminary finite element analysis is conducted to ensure structural rigidity is achieved. The fabrication of the drift trike commences once the structural design is validated through analysis, and the final physical vehicle is tested through experimentation and compared to initial predictions.

Investigation into Lithium-Ion Conductivity and Redox Stability of Selenium-Doped Lithium Lanthanum Titanate

Thu, 01 Jun 2023 00:00:00 GMT

Investigation into Lithium-Ion Conductivity and Redox Stability of Selenium-Doped Lithium Lanthanum Titanate Hu, Lambert Selenium-doped lithium lanthanum titanate of composition Li₀.₃₃La₀.₅₆Ti₁₋ₓSeₓO3 (x = 0, 0.025, 0.050, 0.075) was attempted using a two-step conventional synthesis process to investigate the potential of the material as a solid-state electrolyte in lithium-ion batteries. Impedance spectroscopy data yielded a maximum room temperature bulk conductivity of (1.73 ± 0.10) x 10⁻³ S cm⁻¹ (EBulk = 0.35 ± 0.03 eV) and grain boundary conductivity of (1.20 ± 0.10) x 10⁻⁴ S cm⁻¹ (EGB = 0.37 ± 0.01 eV) for nominal composition x = 0.050. Preliminary stability measurements through three-electrode cyclic voltammetry suggests potential for LLTO stabilization against Li metal anode through further selenium substitution. However, further work is required to confirm the exact elemental composition of selenium-doped samples.

Comparison of Force and Flexibility in Gait Analysis of Sunnystep and New Balance Shoes

Thu, 01 Jun 2023 00:00:00 GMT

Comparison of Force and Flexibility in Gait Analysis of Sunnystep and New Balance Shoes Goetz, Delaney The goal of this paper is to discern if there exist any differences in forces, acceleration, and muscle stiffness when wearing different pairs of footwear. The first pair of shoes tested were New Balance shoes and the second were Sunnystep shoes. From the data, it was shown that on average the body experiences more force when wearing the Sunnystep shoes. The data also demonstrated that the feet had higher acceleration during walking in the Sunnystep shoes than the New Balance shoes, meaning more "stomping" was occurring and thus more impact on the joints. Finally, the Sunnystep shoes had significant effects in decreasing calf stiffness but did not appear to affect hip stiffness. Overall, the Sunnystep shoes were worse for the joints but better for the muscle flexibility.

Mechanical Seven-Segment Display Clock

Thu, 01 Jun 2023 00:00:00 GMT

Mechanical Seven-Segment Display Clock Owen-Block, Benjamin J. Over the ages, many different styles of clocks have been designed, but the seven-segment digital display supplanted most because of its simplicity when using LEDs to illuminate each segment. This project explores how the seven-segment display could be realized in an entirely mechanical clock out of curiosity. This is a great platform to study mechanism design because of the complexity of the problem and the many potential solutions that could exist. To solve this problem, many different mechanisms were considered, but ultimately a barrel cam was chosen to drive linkages that controlled the segments of the clock display. Barrel cams have great versatility; for example, they are widely used in motorcycle gearboxes and controlling tool motion in manufacturing equipment. Through multiple iterations, a successful mechanism using a barrel cam was prototyped that easily cycled through the required numbers when rotated.

Entertainment Station Design for 2.00b (Toy Product Design) PLAYsentation

Thu, 01 Jun 2023 00:00:00 GMT

Entertainment Station Design for 2.00b (Toy Product Design) PLAYsentation Wu, Yufei The scope of this project was to design an entertainment station for the audience of Toy Product Design’s (2.00b) PLAYsentation a.k.a. final presentations, with the goal of creating a festive and inclusive atmosphere with guests in costume and fully engaged with the students’ work The audience was able to walk into Killian Court and interact with various substations before the student playsentations started, including a free giveaway zone and a toy display zone. The theme of the toy product design class this year was Timeless. The design helped the audience enjoy and interact with the themed environment by allowing them to select accessories from multiple historical time periods and fictional worlds, and walk through the space while appreciating student toys designed from various interpretations of the theme. This thess documents the final outcome and the design process including: ideation, CAD and visualization, prototyping and testing, budgeting, and the PLAYsentation service. Reflections on the outcomes are also included.

Decoupled Kinodynamic Planning for a Quadruped Robot over Complex Terrain

Thu, 01 Jun 2023 00:00:00 GMT

Decoupled Kinodynamic Planning for a Quadruped Robot over Complex Terrain Burgess, Michael, Jr. (Michael J.) High-level planning for hybrid-dynamic, legged systems can be challenging due to a need to simultaneously satisfy kinematic and dynamic constraints. Previously developed sampling-based approaches can rapidly generate plans that satisfy kinematic constraints, but often lead to dynamically infeasible trajectories. On the other hand, traditional optimization-based approaches can reliably produce feasible trajectories, but are computationally inefficient. In this work, we leverage the strengths of these popular techniques to develop an advantageous novel motion planning formulation. Our methodology decouples kinematic and dynamic constraints to quickly generate emergent, feasible trajectories for legged systems across complex terrains. We decouple constraints into two separate processes. First, we rapidly sample footstep positions across a given terrain using an RRT-like search algorithm. This allows us to satisfy kinematic constraints without committing to a full state trajectory which could be dynamically infeasible, as is a common failure of other sampling-based approaches. Then, we can solve an optimization problem to generate a dynamically feasible trajectory using these contact positions. Since contact locations have already been determined, our optimization problem has a reduced decision space and does not require inconvenient complementarity constraints. As a result, this optimization can be solved more efficiently than traditional trajectory optimization formulations. Implemented in simulation for a 2D quadruped robot, our novel formulation is shown to generate trajectories in less than 15\% of the computation time needed for traditional, coupled planning methods. Furthermore, experiments demonstrate that our method maintains a consistent average solve time across sets of randomly generated terrains, regardless of their complexity.

Performance Simulation and Powertrain Selection for an Electric Drift Trike Vehicle

Thu, 01 Jun 2023 00:00:00 GMT

Performance Simulation and Powertrain Selection for an Electric Drift Trike Vehicle Rohrbaugh, Joshua S. The design process for an Electric Drift Trike Vehicle is examined. Functional requirements and performance specifications for the trike are created. Driving geometrical relations for the trike’s frame are set based on experiments in rider posture and comfort. The coefficient of friction for the drive wheels is measured to inform powertrain design decisions. Acceleration profiles of the trike are simulated to select a motor and chain drive ratio for the vehicle. A motor controller and battery system are selected to match the requirements of the drive motor. System architecture and safety features of the trike’s electrical system are explained through the startup sequence and wiring diagram of the trike.

Modeling and Feedback Control for a Guyed, Flexible, Tubular Lunar Tower

Thu, 01 Jun 2023 00:00:00 GMT

Modeling and Feedback Control for a Guyed, Flexible, Tubular Lunar Tower Portmann, Victor Paul The Self-Erecting Lunar Tower for Instruments (SELTI) is a compact, self-deploying composite lunar tower being developed in support of the NASA Artemis campaign. SELTI can elevate instrument payloads for the purposes of navigation, power beaming, communication, sensing, and imaging around permanently shadowed lunar regions. SELTI deploys by unspooling a collapsible carbon fiber composite mast, which transitions into an erect tubular state. Due to variations in the manufacturing process, an 11 m deployment without stabilization exhibits eccentricity and large tip deflections, causing the payload orientation to deviate from a center, upright position. To control the payload orientation, SELTI has guy wires that manipulate the tip position of the tower. It is necessary to develop feedback control for this system to achieve the desired orientation of payload instruments. To facilitate control system development and to mitigate the risk of damaging the tower, a tenth-scale physical model of SELTI was designed and built for experimentation and analytical model verification. The system dynamics were approximated using a “first principles” second order model. The model’s step response was compared to reality to assess the model’s accuracy. A full state feedback controller was created using the analytical model and simulated to demonstrate the improved step response.

Design of Mobile Robot for use as a Teaching Platform and Autonomous Navigation and Object Avoidance

Thu, 01 Jun 2023 00:00:00 GMT

Design of Mobile Robot for use as a Teaching Platform and Autonomous Navigation and Object Avoidance Thompson, Kyle There is no end to the depth of learning possible In the field of robotics. However, we are many times limited by the methods we choose to teach ourselves and others. As a result, I looked at the current teaching platforms used, along with others available in the market, and found there was room for something more suitable for my coursework taken so far. This thesis covers the design and implementation of a new autonomous mobile robot teaching platform, which has now been adopted by MIT’s Introduction to Robotics class. This involves the design requirements gathered from looking at what both students and instructors needed to improve their current platform for teaching many of the principles of robotics. The end result has been a successful, open-source mobile robot that is capable of a plethora of autonomous tasks and a high level of modularity—useful for applications in whatever designs are produced by students for the ever-changing term projects.

Optimizing the Design of a Wearable EEG System for Improved Signal Quality

Thu, 01 Jun 2023 00:00:00 GMT

Optimizing the Design of a Wearable EEG System for Improved Signal Quality Ngo, Megan This thesis aims to evaluate the impact of various form factors and magnetic interference on the quality of EEG signals acquired by a wearable EEG device. In order to determine an optimal design that minimizes artifact contamination, various cognitive tasks were observed, and users provided feedback while data was collected. Signal quality was assessed based on the distribution of power across specific frequency bands. The EEG data collected from the glasses demonstrated high sensitivity in detecting brain activity while in the proximity to magnets. Limitations in distinguishing between different brain states were observed due to increased impedance and noise from the design changes. The results thereby call for further investigation and testing to isolate artifacts and improve the wearable EEG technology.

Acoustic Method for Detection Large Pneumothoraxes in the Out-of-Hospital Environment

Thu, 01 Jun 2023 00:00:00 GMT

Acoustic Method for Detection Large Pneumothoraxes in the Out-of-Hospital Environment Motz, Andrew J. Pneumothoraxes and hemothoraxes present a medical emergency that can easily be life threatening. However, improper and unnecessarily aggressive treatment is not uncommon and poses significant risk to patients. Much of this is a result of poor diagnostic aids to assist in the detection of pneumothoraxes out-of-hospital, such as by Emergency Medical Service (EMS) providers. A simple, portable, and accurate method of clinically detecting a pneumothorax would increase the quality of patient care in austere environments. We propose to evaluate the acoustic transfer function of the human thorax for signs that a pocket of air or blood has accumulated within the pleural space. In an attempt to validate this hypothesis, we constructed a phantom model of the human thorax with artificial lungs and pleural spaces capable of being inflated with variable sized air pockets to displace the lungs. The model was subjected to a known acoustic input in the form of a frequency sweep and a low frequency square wave and the output signal was recorded at multiple points on the phantom. Analysis of four characteristics of the output revealed no discernable correlation to the volume or location of a pneumothorax. While the initial attempt to verify the hypothesis was unsuccessful, the theory remains intact. Future work to further this hypothesis could include improving the mathematical model and/or creating a higher fidelity phantom model for experimentation.

Something New, Something Old: Combining Conductive Fibers and Classical Tatting Techniques for Lace Structured Circuits

Thu, 01 Jun 2023 00:00:00 GMT

Something New, Something Old: Combining Conductive Fibers and Classical Tatting Techniques for Lace Structured Circuits Ahteck, Amanda Shayna This project applies lacemaking to circuit design as an applications-based focus at the intersection of traditional craft and emerging e- textile materials. Tatting is a particularly durable method of creating lace by the use of sequential half-hitch knots and loops. This type of lace is fairly stiff, consisting of self-knotting rings and chains that form a design. There are similarities in structure of a knot around a core thread to insulation around a wire. With the use of cotton thread knots around a core conductive thread, the structure of the lace becomes a wire. Similar knotting can be employed to sheath existing wires and fibers. The combination of tatting technique with conductive thread and advanced fibers extends existing exploratory work to unify electronic components for complete lace fabric circuits. The organic structure made of free-standing lace serves as an integrated textile alternative to circuit boards and existing sewn or woven e-textile fabric. The unique lace form factor reveals potential for aesthetically appealing integration with or appending existing garments to add interaction and functionality while also protecting components from strain. Similarly, the lace made with conductive thread on its own can be used as an e-textile with sensing and output functions.

Design of an Ultrasound-Guided Steerable Robotic Catheter for Aortic Interventions

Thu, 01 Jun 2023 00:00:00 GMT

Design of an Ultrasound-Guided Steerable Robotic Catheter for Aortic Interventions Rutherford, Emma (Emma Kristen) Endovascular surgery offers minimally invasive solutions to a variety of pathologies affecting blood vessels, such as aneurysms, dissections, and stenoses. During a standard endovascular procedure, the surgeon makes a small puncture in the femoral artery to insert a steerable catheter, and real time x-ray imaging provides guidance as the surgeon maneuvers it to a target site. A variety of interventional devices, such as stents, grafts, and coils can then be delivered through a catheter to reach the treatment area. While these techniques have many advantages over open surgery, there are still clinical challenges. X-ray vision does not provide a 3-dimensional understanding of the vessels or orientation of the catheter tip, and it is often difficult to distinguish various structures due to poor contrast. It also exposes patients and surgeons to extended periods of radiation. Poor visuals and tedious manipulation often make steering catheters a process of trial and error. Manually steered robotic endovascular systems exist, which assist the surgeon in precise control of the device and reduce the likelihood of human error, but the learning curve associated with them can be steep. Incorporating autonomous steering has the potential to reduce risks caused by surgeon errors, shorten procedure time, and make robotic endovascular surgery accessible for surgeons. As an alternative to x-ray imaging, it is possible to use ultrasound technology as a procedural guidance technique. Here we investigate the use of the Philips Verisight Pro intracardiac echo system to guide the surgeon and map the intravascular environment. This paper covers the design of an initial prototype of a steerable catheter system which integrates a separate advanced 3D echocardiography catheter. With the development of a robust robotic platform, next steps will be to continue developing and testing a simultaneous localization and mapping (SLAM) algorithm for semi-autonomous decision making, with the goal of developing an endovascular surgical system that can maneuver quicker and more precisely than a manually-manipulated catheter.

Analytical Modeling of a Heaving Wave Energy Converter

Thu, 01 Jun 2023 00:00:00 GMT

Analytical Modeling of a Heaving Wave Energy Converter Tyshchenko, Valeriia A broad review of wave power is offered, covering its history as well as the gaps and barriers in its development. The cost of wave power commercialization is identified to be a major challenge, driving the need to prioritize and structure theoretical efforts in order to find a focus area for the largely diffused investment. Specifically, it is proposed to shift the theoretical emphasis from analyzing existing wave energy converters using complex numerical simulation methods to employing simple analytical models in early-stage design decision-making, such as finding the most promising mode of wave power generation to dedicate research efforts to. The heaving converter type is therefore chosen as an example of using simple analytical analysis in evaluating maximum theoretical capability of a single wave power generation mode – vertical translation. Given evidence of successful application of control theory to approximating wave interactions, a linear control theory-based model of a simplified heaving device is proposed, with the necessary wave theory background discussed in detail. The implementation of the model in MATLAB and the associated optimization of the converter design parameters are described in the context of a case study that uses experimental ocean data. It has been found that a heavier heaving converter shaped like a streamlined cylindrical buoy can absorb 99.7% of the wave energy input. On the other hand, a lighter bluff buoy absorbing 30.1% of the energy has twice as large of a frequency bandwidth. Nevertheless, it should be noted that the bandwidth values are far from typical wave frequencies which leads to a conclusion that bandwidth does not carry practical importance in the context of the model developed. A sensitivity analysis looking into dependence of both the coefficient of absorption and the bandwidth on the buoy design parameters is performed. The assumptions behind the model as well as its limitations are discussed. The heaving model proposed can serve as a starting point in the process of selecting a wave power generation mode with the most theoretical potential. It can also be used as a basis for developing more complex analytical techniques to complement or substitute resource-intensive numerical tools with more efficient approaches.

Energy consumption and traffic conditions of the Philadelphia-Paoli electrification of the Pennsylvania Railroad

Thu, 01 Jan 1920 00:00:00 GMT

Energy consumption and traffic conditions of the Philadelphia-Paoli electrification of the Pennsylvania Railroad Logan, John William, 1952-; Kinghorn, Archibald H.; Elliott, John T. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1920

Direct synthesis of acetylene from carbon and hydrogen

Tue, 01 Jan 1957 00:00:00 GMT

Direct synthesis of acetylene from carbon and hydrogen Begany, Dennis.; Cowen, Arthur. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1957; Bibliography: leaves 37-38.

37,500 K.V.A. floating power plant

Wed, 01 Jan 1947 00:00:00 GMT

37,500 K.V.A. floating power plant Cavicchi, Richard H. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1947; Bibliography: leaf 76.

The atomic theory as applied to gases, with some experiments on the viscosity of air

Sat, 01 Jan 1876 00:00:00 GMT

The atomic theory as applied to gases, with some experiments on the viscosity of air Holman, Silas W. (Silas Whitcomb), 1856-1900. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1876

A Hebrew community center for Lowell, Massachusetts

Sat, 01 Jan 1938 00:00:00 GMT

A Hebrew community center for Lowell, Massachusetts Weisberg, Eugene B. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1938; Includes bibliographical references.

Demand analysis of rail commuter transportation.

Fri, 01 Jan 1965 00:00:00 GMT

Demand analysis of rail commuter transportation. King, Carl Kenneth. Thesis: B.S., Massachusetts Institute of Technology, Department of Economics and Social Science, 1965

Leveling Out The Left Field: Toy Design for Left-Handed Children

Thu, 01 Jun 2023 00:00:00 GMT

Leveling Out The Left Field: Toy Design for Left-Handed Children Gatta, Audrey The world is designed for right-handers: starting from a young age, left-handed children are being stimulated from a right-handed perspective, including through their interactions with toys, tools, interior design, sports, and more. While left-handers may be able to adapt to certain right-handed tools, it is important to design for left-handers in several realms, including toys, since children are developing fine motor skills as they play. Furthermore, a child’s environment influences hand preference, so it is viable to design in such a way that stimulates the use and development of their dominant hand. This thesis explores how and why handedness should be addressed in toy design, culminating with a prototype of a diagnostic toy that assists in identifying handedness preferences while also targeting play with a specific hand through environmental bias and bilateral coordination.

Satan’s Game

Thu, 01 Jun 2023 00:00:00 GMT

Satan’s Game Carvajal, Mikel The following work is the first three chapters, around 19,000 words, of a prospective fantasy book. Set in Westchester, New York, it follows a group of teenagers starting their senior year of high school when a number of impossible occurrences rope them into a magical world hidden within their town. Daniel, an avid fan of Dungeons and Dragons, is the dungeon master for his other four friends that would love most to ignore the rest of the world and keep making worlds for them to explore. The problems of school, dramas of teenagers, and of course the surprises of magic all create a senior year he is incredibly unprepared for, all of which is unhelped by his anxiety that he understands less than the magic.

Stories through Data: The Relationship between COVID-19 and Data Graphics on The New York TimesFront Page

Thu, 01 Jun 2023 00:00:00 GMT

Stories through Data: The Relationship between COVID-19 and Data Graphics on The New York TimesFront Page Green, Juliana C. The COVID-19 pandemic hit the US in early 2020, radically redefining the daily patterns of millions of people. This project investigates the impact of the pandemic on data graphics usage in reporting and its implications for data literacy. The survey comprises 226 data graphics appearing on the front page of The New York Times from 2019 through 2022. Graphics were collected, categorized along a number of metrics, and visualized along with pandemic caseload and death data from The New York Times. Analysis reveals that these graphics tended to be centrally located above the fold, brightly colored, and took on one of three graphical architectures––time series, bar graph, or map. Perhaps most notably, the average number of front page information graphics per month more than tripled (from 1.6 to 5.2) in the 4 years from 2019 to the end of 2022. However, the average size of graphics followed no consistent trend. Separately, the increase in data graphics coincides with a decrease in test scores indicative of data literacy rates among school children, in a context where data literacy was already poor across age groups. These results bring up concerns regarding critical reader engagement with news graphics.

The Bengal School of Art and Nihonga (19021928): Art Toward a Modern Asian Identity

Thu, 01 Jun 2023 00:00:00 GMT

The Bengal School of Art and Nihonga (19021928): Art Toward a Modern Asian Identity Guo, Katherine Q. Caol At the turn of the twentieth century, both India and Japan increasingly sought to create new modern identities separate from Western influence. These ambitions are reflected in the philosophies of two corresponding art movements, the Bengal School of Art and nihonga which are both considered to be pivotal to the development of modern Indian and Japanese art respectively. India had been ruled and colonized by Great Britain for almost a century and a half with Britain establishing state-run art institutions that mandated the standards of Indian art as well as commodifying it for European consumption. Similarly, though Japan was never directly colonized by a European state in the same manner, it felt pressure to assert its growing power by adopting and emulating Western aesthetics. In contrast, the Bengal School and nihonga both actively rejected Euro-American art techniques. Instead, the artists active in these movements were inspired by traditional Indian and Japanese forms. Initially, they developed their ideologies independently. However, in 1902, Okakura Kazuko, a Japanese art historian and vocal proponent of nihonga, visited Calcutta, India, staying with a prominent Bengali family, the Tagores, known for their contributions to Indian art, literature, music, and social reform. During this initial visit, as well as subsequent voyages to India and Japan by associated artists from the two groups, there was significant cross-pollination of ideologies, techniques, content, and aesthetics. For instance, the hazy ‘wash’ technique introduced by the nihonga artists, known as morotai, was adopted by the Bengal School of Art artists and became one of the movement’s defining features. Another key theme these two groups of artists explored was the tension between nationalism and transnational Pan-Asianism, the idea that all of Asia should be united economically, culturally, and politically in opposition to European values. Overall, this thesis seeks to contribute to a deeper understanding of the nuances of artistic exchange between India and Japan during the early twentieth century and how these interactions sometimes transcended national boundaries to develop a broader sense of Pan-Asian identity.

A Microbial Survey of Lake Kivu: Mechanisms of Nitrogen Cycling

Thu, 01 Jun 2023 00:00:00 GMT

A Microbial Survey of Lake Kivu: Mechanisms of Nitrogen Cycling Przydzial, Kaitlyn Ocean Anoxic Events (OAEs) are periods in Earth’s history during which large por-tions of the oceans contain decreased amounts of oxygen. OAEs can be very difficult to study since modern oceans are generally well-oxygenated. Here Lake Kivu, a meromictic lake with deep anoxic layers, is presented as a potential OAE analogue and is used to study a proposed nitrogen cycling mechanism that could explain the characteristic 𝛿¹⁵N excursions associated with OAEs. Biomarkers are isolated from sediment samples and analyzed across depth below the lake floor. The results are consistent with a biologically mediated nitrogen cycling mechanism, shedding more light on a potential mechanism to explain nitrogen cycling in OAEs.

Eden Creek

Thu, 01 Jun 2023 00:00:00 GMT

Eden Creek Powers, Hudson “Eden Creek” is the first four chapters of a fictional drama and supernatural horror following the story of a protagonist, August, as she reconnects with an old friend and explores the town of Eden Creek. The chapters exhibited focus primarily on dialogue, world-building, and characterization of the two main characters, August and Ellis. Dialogue is a primary driver of characterization and narrative, serving as a vehicle for studying our characters via their interactions with each other. The piece also aims to introduce elements of both a hard magic system -building out fundamental rules of supernatural phenomenon- and trace elements of a soft magic system -implying some unknown “aliveness” to Eden Creek as a physical location. Literary elements endemic to the horror genre, such as suspense, are also used to establish tone and mood.

Probing Local Many-Body Dynamics with Random Quantum Circuits

Thu, 01 Jun 2023 00:00:00 GMT

Probing Local Many-Body Dynamics with Random Quantum Circuits Cui, Laura L. Random quantum circuits are an attractive model for the behavior of complex many-body physics, due to their analytic tractability as well as ability to reproduce the behavior of chaotic quantum systems. Recent progress in elucidating their structure has led to an improved understanding of quantum complexity, both in the context of quantum circuit complexity and state preparation, as well as for the task of measuring and distinguishing quantum states. However, previous results in the literature often rely on the properties of specific theoretical models, or require unrealistic assumptions about the dynamics and experimental realization of large systems. In this thesis we discuss the application of random circuits to probe local dynamics in many-body systems, focusing on the regime in which the depth of the circuit is small compared to the size of the system. Motivated by recent results, we provide a definition for local scrambling based on the difficulty of distinguishing the resulting distribution from a Haar-random transformation in the case where only a region of fixed size may be accessed. We prove that up to the second moment, local scrambling of a product state input occurs in log depth, i.e. requiring circuit depth at most proportional to the logarithm of the size of the region, and is independent of the total system size. In addition, we consider models for classifying topological phases and characterizing the entanglement structure of quantum matter. In particular, we describe the immediate application of our above result to bounds on the detection of these phases. We then discuss the topological entanglement entropy (TEE), a quantity related to the quantum conditional mutual information. Under standard assumptions, we prove that in the trivial phase, spurious contributions to the TEE decay in the limit as the size of the system goes to infinity, suggesting that the TEE is a robust indicator of topological order.

Neural-Network Based b-Tagging in the CMS Level 1 Trigger System

Thu, 01 Jun 2023 00:00:00 GMT

Neural-Network Based b-Tagging in the CMS Level 1 Trigger System Chambers, Aidan D. The Phase II upgrade of the Compact Muon Solenoid (CMS) detector for the High Luminosity Large Hadron Collider will greatly expand the hardware capabilities of the Level 1 Trigger (L1T) system. With the advent of tracks in the L1T, these upgrades bring the idea of b jet identification within the L1T environment into the realm of feasibility for the first time at CMS. This thesis focuses upon the development of a neural network-based algorithm for the identification of jets originating from bottom quarks in the CMS detector. The algorithm is designed for the timing constraints of the L1T, using seeded cone jet reconstruction of PUPPI algorithm objects as inputs. We present the input data, architecture, and training of the network with performance on simulated tt-bar events. We then focus on the application of the network towards the HH to bbbb decay channel, where our neural network-based trigger displays a 12% increase in trigger efficiency for events useful for measuring Higgs self-coupling. Finally, results are presented for the ongoing progress on implementations of this b-tagging algorithm onto Field Programmable Gate Arrays suitable for the L1T environment. From these results we conclude that b-tagging is possible in the Phase II L1T, a novel achievement that opens the chance to study numerous new physics processes with the first instance of L1T heavy flavor tagging at the LHC.

Quantum Computation and Simulation using Fermion Pair Registers

Thu, 01 Jun 2023 00:00:00 GMT

Quantum Computation and Simulation using Fermion Pair Registers Sun, Xiangkai Quantum gas microscopes provide a powerful toolbox for probing quantum many-body physics. Recently, an exciting progress has been reported on realizing a large-scale quantum register of fermion pairs with a quantum gas microscope, in which tightly localized fermion pairs are used to encode qubits exhibiting long coherence time and robustness against laser intensity noise. In this thesis, we propose and analyze a new approach for quantum computation and simulation, leveraging fermionic particles on optical lattices under quantum gas microscopes. We engineer the SWAP gate and high-fidelity controlled-phase gates by adjusting the fermion hopping as well as the Feshbach interaction between two fermions. These gates, together with previously demonstrated single-qubit rotations, form a universal gate set. Furthermore, by modulating the strength of the Feshbach interaction, one can realize 2D quantum Ising Hamiltonians in a programmable geometry with tunable transverse and longitudinal fields. In addition, we present a sample-efficient protocol to characterize engineered gates and Hamiltonian dynamics by improving classical shadow process tomography to require minimal experimental controls. Our work opens up new opportunities to harness existing ultracold quantum gas techniques for quantum information processing.

Deterministic Barcoding of Neuron Identities through Multicolor Fluorescent Markers in C. elegans

Thu, 01 Jun 2023 00:00:00 GMT

Deterministic Barcoding of Neuron Identities through Multicolor Fluorescent Markers in C. elegans Shim, Seung Hyeon Mapping the connectivity of neurons, or the brain connectome, with a clear identification of neuron types and functions is a complicated problem that hinders the development of potential therapeutic interventions. Without understanding the identities of neurons that have fundamental roles in neurological or psychiatric disorders, uncovering the disease mechanism and pathology to observe, control, and even repair neural dynamics remains challenging. In this work, we achieve live animal imaging and cell identification by generating a multicolored fluorescent map of different neurons in C. elegans. We take advantage of neuron type-specific promoters to construct transgenes that label each neuron type with unique red, green, and blue fluorescent colors. We also tag subcellular markers of the nucleolus and nuclear membrane with fluorescent proteins to allow for a combinatorial barcode for neuron types, allowing the differentiation of neurons at a single-cell resolution. Through multicolor barcoding of individual neurons, we distinguish different cell types in vivo, helping reconstruct parts of the C. elegans connectome. With this deterministic strategy, we hope to enable cell typing throughout development and advance the understanding of both the connectome and the shifts in neural circuitry.

Developing and Characterizing Sources of Quantum States of Light: from Single Photons to Million-Photon Fock States

Thu, 01 Jun 2023 00:00:00 GMT

Developing and Characterizing Sources of Quantum States of Light: from Single Photons to Million-Photon Fock States Pontula, Sahil One of the central goals of quantum optics is the generation and control of quantum states of light. Chief among these states are Fock states, the fundamental eigenstates of the electromagnetic Hamiltonian with a perfectly-defined photon number. Decades of research have been devoted to producing Fock states, but no known source can produce Fock states at macroscopic intensities and optical wavelengths. Such a source would revolutionize applications ranging from all-optical quantum information processors to quantum sensing far below the shot noise limit. Here, I describe two projects related to the development of quantum states of light, focusing on Fock state sources. First, I demonstrate an improved characterization of single photon emitters (SPEs) in hexagonal boron nitride (hBN) at optical wavelengths. Specifically, I demonstrate how one can extract information about electron-phonon coupling in SPEs from photoluminescence spectra in order to characterize fidelity in generating N=1 Fock states. Second, I consider methods for generating large N Fock states. I describe a novel method to generate highly intensity-noise squeezed states of light and demonstrate the feasibility of their production on existing semiconductor lasers. This method combines nanophotonics and nonlinear optics to generate photonic dissipation ("nonlinear dispersive loss'') that depends nonperturbatively on the photon number itself. This allows unprecedented squeezing of the intracavity photon number distribution, approaching Fock states of millions of photons. I provide a thorough analysis of intensity and phase noise in these semiconductor lasers and propose realistic platforms amenable to the effects described here.

Wok Palace 88

Thu, 01 Jun 2023 00:00:00 GMT

Wok Palace 88 Li, Felix “Wok Palace 88,” is a parafictional and defunct Chinese-American restaurant brought back to life through the institutional process of excavating, archiving, and displaying. The restaurant is based around shutdown restaurants in Greater Boston including Eldo Cake House and Joyce Chen’s restaurants. Wok Palace 88 consists of two performances: the first titled “A Delivery” where I biked around the greater-Boston area delivering menus to spaces that once housed Chinese restaurants. The second performance titled “A Soft Grand Opening” is the grand opening of the fictional restaurant where I presented and archived fabricated artifacts from the restaurant, as well as embodied the histories ingrained in the objects. I served as the artist, archivist, curator, historian, collector, and subject. These performances were acts of resistance against American Orientalism and engaged with moments and artifacts related to the restaurant and its experience. The project asks what it means to embed time, memory, and place into an object; and consequently how are they valued and commodified? It approaches these questions with the historical implications associated with each item, such as the mystical origins of the chop suey. It is a provocation on what it means to archive and institutionalize cultural objects, how histories connected to material bodies are told, and ultimately the futility of preservation. The performances were an interrogation into the Eurocentric fetishization and hoarding of Chinese material goods. It asks us to reckon with the exoticization of Asian culture and unrecognition of Asian American art. Consequently, it will investigate what it means to archive and institutionalize cultural objects. Wok Palace 88 is positioned as a defunct restaurant because of the impossibility of the defunct to generate futures. It is because it’s defunct that we must begin to excavate and uncover histories.

Crowdsourcing Feedback and Augmenting 3D Visualizations: Online Collaboration Tools for Gamified Participatory Design Workshops

Thu, 01 Jun 2023 00:00:00 GMT

Crowdsourcing Feedback and Augmenting 3D Visualizations: Online Collaboration Tools for Gamified Participatory Design Workshops Zhang, Jenny Crowdsourcing Feedback and Augmenting 3D Visualizations: Online Collaboration Tools for Gamified Participatory Design Workshops is an investigation into how digital tools can be designed to facilitate and enhance the participatory process. The participatory process this thesis focuses on is the Block by Block playbook, a 16 step process curated by Mojang, the studio behind Minecraft, and UN-Habitat. The methodology utilizes the simple voxel-based blocks in Minecraft as a “digital Lego” to empower anyone to learn to express their ideas in 3D in a matter of hours or days. The Block by Block foundation funds and educates community organizers to run participatory workshops that use Minecraft to improve public spaces in more than 35 countries worldwide. Using previous Block by Block workshop participant feedback as a pseudo-needs analysis, this thesis proposes a new external web tool, The Block by Block Expansion Pack, that augments the Minecraft Co-design Workshop Phase with a few logistical changes. The current Block by Block procedure separates the ideation and design stage from the feedback stage which leaves little room for design iteration. The Block by Block Expansion Pack aims to address the participants’ request for more opportunities to converse with the greater community throughout the workshop by creating a web platform that allows anyone to view, annotate, and comment on each group’s latest progress. This extension serves as a medium to incorporate ideas from a more diverse audience, improve understanding of proposed planning changes, and increase sense of ownership of the public spaces created from the workshop. In addition to the communication features mentioned above, the platform also keeps a record of the design progression and iterations through a version history system and provides an interface to easily compare two builds. This tool has the potential to be used throughout the workshop, from the initial brainstorm to post workshop data collection.

I Come Home to Myself

Thu, 01 Jun 2023 00:00:00 GMT

I Come Home to Myself Adamu, Kidist I Come Home to Myself is a documentary film following Marglucy and Faduma, presenting a portrait of their individual relationships to beauty and beauty work. The documentary contrasts the varied experiences that have shaped their beauty practices as well as their negotiations with beauty work. The film also explores the different internal and external forces that influence their beauty ideals and the conclusions they arrive at.

Speleothem-Based Hydroclimate Reconstruction of Northeastern Mexico Across the Last Deglaciation

Thu, 01 Jun 2023 00:00:00 GMT

Speleothem-Based Hydroclimate Reconstruction of Northeastern Mexico Across the Last Deglaciation Intveld, Aviva B. As anthropogenic global warming intensifies, climate models predict more frequent drought conditions across Northeastern Mexico, but regional paleoclimate data is necessary to inform the spatial extent and severity of these droughts. In this thesis, we present a centennial-scale resolution record of Northeastern Mexico hydroclimate spanning 21.77 to 11.56 ka using a speleothem from Rioverde, San Luis Potosí, Mexico. We use trace element ratio data to reconstruct local water balance (P - ET) and compare our results to neighboring proxies and climate models to investigate regional coherency and climate forcings. Our record captures wet conditions during the Last Glacial Maximum, dry conditions during Heinrich Stadial 1, and wet conditions during the Bolling-Allerod Warming, with implications for defining glacial climate and assessing the Mesoamerican North-South precipitation dipole on millennial to orbital timescales. Our results also demonstrate a dynamic control on precipitation via changes in the Atlantic-Pacific SST gradient. Furthermore, our results help fill a crucial gap in our knowledge of the climatic background of the First Peopling of the Americas and offer a potential route for the Peopling of Mexico between 15.5 and 13 ka. Ultimately, this work provides a precisely dated and high-resolution record in an understudied region to better predict future climate and reconstruct human history.

Near-Infrared Spectroscopy of Near-Earth Asteroids: 3122 Florence, (357439) 2004 BL86, 1036 Ganymed, and 4055 Magellan

Thu, 01 Jun 2023 00:00:00 GMT

Near-Infrared Spectroscopy of Near-Earth Asteroids: 3122 Florence, (357439) 2004 BL86, 1036 Ganymed, and 4055 Magellan Larsen, Skylar S. The near-infrared spectra of four near-Earth asteroids, 3122 Florence, (357439) 2004 BL86, 1036 Ganymed, and 4055 Magellan, were analyzed for traces of surface water. NEAs are widely thought to be the source of water and organics delivered to early Earth. Additionally, some NEAs are considered potentially hazardous objects (PHOs), and they could make threateningly close approaches to our planet. The Infrared Telescope Facility (IRTF), located at Mauna Kea, Hawaii, was used to measure long wavelength cross-dispersed (LXD) spectra of these four asteroids with SpeX mode. The measured spectra wavelength ranged from 1.67-4.2 μm, which includes the 3-μm feature attributed to water/hydroxyl. The 3μm spectral feature was found on Florence, but not on 2004 BL86; meanwhile, the Ganymed and Magellan results were inconclusive. Discovering water on a celestial body such as Florence, an S-type asteroid, is highly unusual and warrants further study.

running away, running towards: a collection of sestinas

Thu, 01 Jun 2023 00:00:00 GMT

running away, running towards: a collection of sestinas Zhu, Alan Y. These poems of vulnerability, love, and loss trace the journey of a poet slowly coming into their identity. They emphasize the intensity and quality of the mundane, with poems found in bus stops, bowls of soup, quiet mornings, and inkstains. The repetition of words in the sestina form also gives these poems an obsessive quality, reflecting how we move forwards even as we keep returning to the same thoughts, ideas, places, and words. The thesis consists of three parts. The first, “running away,” grapples most deeply with what it means to lose and fear love; the second, “on the edge,” focuses on moments spent in uncertainty, where we are not so confident about what comes next or what to do. The final, “running towards,” pushes us to keep running towards life in spite of it all, and to choose to become our full, individual selves

Pelagic

Thu, 01 Jun 2023 00:00:00 GMT

Pelagic Gazdus, Hannah The following submission contains five chapters from the beginning of the fantasy novel Pelagic, the first book in a trilogy set in a secondary world. The rough draft of the book was completed January 2023, and the following chapters are either rewrites or new content produced for the second draft. Pelagic follows Maeve Brontide as she recruits allies to help her and her brother rescue their parents from the shipping corporation Argent. In its pursuit of wealth and influence, Argent has killed one of the four gods to steal his power over the sea and sky, known as Aeolia. As the Brontide parents are knowledgeable about Aeolia, their family has been in-hiding for the past several years to escape Argent. After her parents are kidnapped, Maeve navigates her new Aeolian powers and meets other individuals who have suffered as a result of Argent’s conquests. By the end of the novel, she decides she can no longer step aside and let Argent wreak more destruction, even if that means risking the safety of her and her family. After rescuing her parents and friends and meeting the goddess Eurus, Maeve commits to taking down Argent. Pelagic and its subsequent novels Abyssal and Pacific provide an exploration of responsibility, power, and agency; trauma and mental health; faith; and the search for meaning. Now that the death of a god has released magic back into the world, the characters must debate what purpose that magic should be used for; could there be a balance among Aeolia’s use to accrue capital, to provide humanitarian relief, and/or to create? In particular, the author’s background as a mechanical engineer and artist has inspired her to explore the ways elemental magic can influence architecture, construction, and art.

Resummation in Deep Inelastic Scattering

Thu, 01 Jun 2023 00:00:00 GMT

Resummation in Deep Inelastic Scattering Malshi, Luen Deep Inelastic Scattering is the process where an electron collides with a proton at high energies, thus serving as a probe for the internal proton structure. Precise computation of deep inelastic scattering cross sections is crucial for testing our current understanding of the Standard Model. The cross section for this process can be determined through perturbation theory for high momentum transfer. However, in the elastic limit of this process, perturbation theory breaks down, and nonperturbative QCD interactions cannot be ignored. Therefore, new techniques are needed to compute cross sections. Resummation is the process in which the perturbative series in the cross section is reordered and then resummed to give a prediction that includes nonperturbative QCD effects. In this paper we merge the resummed series into a redefinition of the partonic distribution functions. Through this new technique, the new redefined cross section converges quicker with each added perturbative order towards cross section values obtained through conventional resummation.

The Discovery and Characterization of an Ultracompact Hot Subdwarf and Brown Dwarf Binary System

Thu, 01 Jun 2023 00:00:00 GMT

The Discovery and Characterization of an Ultracompact Hot Subdwarf and Brown Dwarf Binary System Blomberg, Lisa Nicole Stellar binary systems are astronomical objects made of two stars gravitationally bound to each other. In some of these systems, the stars are so close that they interact with each other and affect the formation and evolution of one another. As a result, understanding these objects can provide insight into various stellar processes and astrophysical phenomena. In my project, I focused on studying a type of ultra-compact binary system called an HW Vir class binary – which is comprised of a hot sub dwarf and a brown dwarf. Because HW Vir systems can only be produced through the common envelope effect (CEE), understanding their physical parameters allows us to better understand the limitations of the CEE. For example, by studying binaries with the lowest mass companion that have survived the CEE, it allows us to draw conclusions about the lower bound on the companion mass that is able to survive envelope ejection. In my thesis, I outline the methods I used to search for these binary systems and model the lightcurve of ZTFJ2203+4824, a 78-minute orbital period HW Vir class binary that I discovered.

A thesis entitled storage and power possibilities on the Ausable River

Fri, 01 Jan 1926 00:00:00 GMT

A thesis entitled storage and power possibilities on the Ausable River Kinzey, Albert F. (Albert Freeman); Larratt, Arthur E. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil and Sanitary Engineering, 1926

Design of proposed residential subdivision in Brookfield, Connecticut

Wed, 01 Jan 1941 00:00:00 GMT

Design of proposed residential subdivision in Brookfield, Connecticut Watson, Douglas.; Van Greenby, Stanley H. Thesis: B.S., Massachusetts Institute of Technology, Department of Building Engineering and Construction, 1941; Includes bibliographical references.

An investigation of the variation of the heat transfer coefficient in natural convection due to boundary layer interaction in adjacent vertical plates

Sun, 01 Jan 1961 00:00:00 GMT

An investigation of the variation of the heat transfer coefficient in natural convection due to boundary layer interaction in adjacent vertical plates Sununu, John H. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1961; Includes bibliographical references (leaf 63).

Investigation of frothing in molasses

Mon, 01 Jan 1951 00:00:00 GMT

Investigation of frothing in molasses Brody, Aaron L. Thesis: B.S., Massachusetts Institute of Technology, Department of Food Technology, 1951; Bibliography: leaves 41-43.

The preparation of hydrogen polysulfide in the gas phase

Mon, 01 Jan 1951 00:00:00 GMT

The preparation of hydrogen polysulfide in the gas phase Bruce, H. William.; Mattana, John L. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1951; Bibliography: leaf 28.

Freezing and thawing of exterior tile mortar joints

Sat, 01 Jan 1949 00:00:00 GMT

Freezing and thawing of exterior tile mortar joints Reynolds, Paul T.; Warren, Richard W. Thesis: B.S., Massachusetts Institute of Technology, Department of Building Engineering and Construction, 1949

Optimal control of positioning system with non-linear rate-type drive.

Thu, 01 Jan 1970 00:00:00 GMT

Optimal control of positioning system with non-linear rate-type drive. Sasaki, Kōji. Thesis: Mech. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1970; Bibliography: leaves [74]-[75].

Metaphors of nature : the vision of Cézanne, Monet, and Poincaré.

Sun, 01 Jan 1978 00:00:00 GMT

Metaphors of nature : the vision of Cézanne, Monet, and Poincaré. Cavicchi, Elizabeth Mary. Thesis: B.S., Massachusetts Institute of Technology, Department of Humanities, 1978; Includes bibliographical references.

Strength of current produced by the microphone as determined by pressure and material of electrodes

Sun, 01 Jan 1888 00:00:00 GMT

Strength of current produced by the microphone as determined by pressure and material of electrodes Sabine, Annie Ware. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1888

A model for molten fuel movement in an unfailed LMFBR pin.

Mon, 01 Jan 1973 00:00:00 GMT

A model for molten fuel movement in an unfailed LMFBR pin. Kee, James Alfred. Thesis: Nuc. E., Massachusetts Institute of Technology, Department of Nuclear Engineering, 1973; Bibliography: leaves 129-132.

Investigation of acoustic field non-linearities by suspension of particles in a cylindrical resonating cavity.

Mon, 01 Jan 1973 00:00:00 GMT

Investigation of acoustic field non-linearities by suspension of particles in a cylindrical resonating cavity. Fleishon, Neil Lawrence. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1973; Bibliography: leaf 44.

Pressure measurements for steady state inspiratory flow in a model of the central airways.

Sat, 01 Jan 1972 00:00:00 GMT

Pressure measurements for steady state inspiratory flow in a model of the central airways. Watson, William Walcott. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1972; Includes bibliographical references.

Statistical analysis for predicting success at MIT

Wed, 01 Jan 1986 00:00:00 GMT

Statistical analysis for predicting success at MIT Fitzmaurice, Jean Anne. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1986; Bibliography: leaf 27.

Design and construction of a vibrating hypodermic syringe for retrobulbar block injection

Wed, 01 Jan 1986 00:00:00 GMT

Design and construction of a vibrating hypodermic syringe for retrobulbar block injection Fleischner, Richard Eric. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1986; Bibliography: leaf 23.

Force fits

Fri, 01 Jan 1915 00:00:00 GMT

Force fits Basu, Kshitish Chandra. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1915

Endoscopic surgery--an assessment of laparoscopic and arthroscopic techniques and instrumentation

Wed, 01 Jan 1992 00:00:00 GMT

Endoscopic surgery--an assessment of laparoscopic and arthroscopic techniques and instrumentation Vasan, Sandhya. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1992; Includes bibliographical references (leaves 83-85).

Dynamic pressures and plating response in a medium speed planing hull

Thu, 01 Jan 1959 00:00:00 GMT

Dynamic pressures and plating response in a medium speed planing hull Brooks, Richard B.; Clark, Robert T.; Quiñones Lopez, Carlos. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Naval Architecture and Marine Engineering, 1959; Includes bibliographical references (leaves 94-96).

Removal of copper from the reverberatory slag by means of iron sulfide

Thu, 01 Jan 1942 00:00:00 GMT

Removal of copper from the reverberatory slag by means of iron sulfide Kocatopcu, Şahap Şefkati. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1942; Includes bibliographical references (leaf 25).

Magnetohydrodynamic ship propulsion using multipole magnetic fields

Fri, 01 Jan 1965 00:00:00 GMT

Magnetohydrodynamic ship propulsion using multipole magnetic fields Barragan Schenone, Eduardo José. Thesis: S.B., Massachusetts Institute of Technology, Department of Electrical Engineering, 1965; "September 1965."; Includes bibliographical references (leaf 65).

Experimental study of the action of the flat nose diamond point lathe tool

Thu, 01 Jan 1891 00:00:00 GMT

Experimental study of the action of the flat nose diamond point lathe tool Mitchell, Guy Edward.; Libbey, Ernest Linwood. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1891

Comparative tests upon the strength of unbleached and bleached cotton cloth

Thu, 01 Jan 1891 00:00:00 GMT

Comparative tests upon the strength of unbleached and bleached cotton cloth Childs, Edward Lincoln.; Adams, William Hussey. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1891

The effect of convective instabilities and transverse magnetic fields upon crystals grown from the melt.

Mon, 01 Jan 1973 00:00:00 GMT

The effect of convective instabilities and transverse magnetic fields upon crystals grown from the melt. Flego, Steven Edward. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy and Materials Science, 1973; Includes bibliographical references.

A statistical analysis of weekly changes in the market price of National Dairy Common Stock for the period, 1950-1960

Sun, 01 Jan 1961 00:00:00 GMT

A statistical analysis of weekly changes in the market price of National Dairy Common Stock for the period, 1950-1960 Cryer, Charles Richard. Thesis: B.S., Massachusetts Institute of Technology, School of Industrial Management, 1961; Includes bibliographical references (leaf 71).

The electrical activity of the heart as measured at the body's surface.

Fri, 01 Jan 1971 00:00:00 GMT

The electrical activity of the heart as measured at the body's surface. Hansen, Reid Herman. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1971; Bibliography: leaf 36.

The construction of a pulsed ruby laser and its employment in taking holograms.

Fri, 01 Jan 1971 00:00:00 GMT

The construction of a pulsed ruby laser and its employment in taking holograms. Haffner, James William. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1971; Bibliography: leaf 29.

Microstructure of superheated, splat-cooled specimens of cobalt - 25 percent tin.

Sat, 01 Jan 1966 00:00:00 GMT

Microstructure of superheated, splat-cooled specimens of cobalt - 25 percent tin. Capitanio, Francis Emil. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1966; Bibliography: leaves 34-36.

An experimental investigation of stress relations among the rivets of a web splice

Wed, 01 Jan 1936 00:00:00 GMT

An experimental investigation of stress relations among the rivets of a web splice Timmerman, William L. (William Lee) Thesis: B.S., Massachusetts Institute of Technology, Department of Architectural Engineering, 1936

A structural study of rhodium carbonyl chloride and rhodium carbonyl bromide

Fri, 01 Jan 1960 00:00:00 GMT

A structural study of rhodium carbonyl chloride and rhodium carbonyl bromide Wilt, John Robert, 1939- Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1960; Includes bibliographical references (leaf 23).

Sequestration of rabbit platelets labelled with Cr⁵¹

Fri, 01 Jan 1960 00:00:00 GMT

Sequestration of rabbit platelets labelled with Cr⁵¹ Ruttenberg, Michael. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1960; Includes bibliographical references (leaves 22-23).

The attempted oxidation of p-toluic, m-toluic, and dihydrocinnamic acids by potassium hypochlorite ; Part II, A determination of the degree of E₁ character of the methanolyses of a series of phenyldimethylcarbinyl chlorides

Fri, 01 Jan 1960 00:00:00 GMT

The attempted oxidation of p-toluic, m-toluic, and dihydrocinnamic acids by potassium hypochlorite ; Part II, A determination of the degree of E₁ character of the methanolyses of a series of phenyldimethylcarbinyl chlorides O'Connor, Brian R. (Brian Russ) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1960; Includes bibliographical references (leaf 11).

Crystallization kinetics of lunar composition 15555.

Mon, 01 Jan 1973 00:00:00 GMT

Crystallization kinetics of lunar composition 15555. Klein, Lisa Carol. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy and Materials Science, 1973; Includes bibliographical referencess.

Two-beam deckhouse theory including shear deflection.

Mon, 01 Jan 1973 00:00:00 GMT

Two-beam deckhouse theory including shear deflection. Kinay, Nadir Osman. Thesis: Ocean E., Massachusetts Institute of Technology, Department of Ocean Engineering, 1973; Includes bibliographical references.

Study of an audio oscillator stability dependence on tempera ture.

Mon, 01 Jan 1973 00:00:00 GMT

Study of an audio oscillator stability dependence on tempera ture. Kim, Chong-Soo. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1973

Absolute pitch training.

Mon, 01 Jan 1973 00:00:00 GMT

Absolute pitch training. Kiehl, John Clark. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1973; Bibliography: leaves 29-30.

A design for a mosque in the Arabic style of architecture

Fri, 01 Jan 1915 00:00:00 GMT

A design for a mosque in the Arabic style of architecture Abdulnour, Bahjat Amin. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1915

Transient responses in multiple plate absorption columns

Fri, 01 Jan 1960 00:00:00 GMT

Transient responses in multiple plate absorption columns Morris, William C. (William Charles) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1960; Includes bibliographical references (leaves 38-39).

The vulcanization of rubber by induction heating

Fri, 01 Jan 1960 00:00:00 GMT

The vulcanization of rubber by induction heating Morgan, Allan Clark. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1960; Includes bibliographical references (leaves 44-45).

Potential energy gradient on a perforated plate

Fri, 01 Jan 1960 00:00:00 GMT

Potential energy gradient on a perforated plate McDowell, Howard M. (Howard Merrideth) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1960; Includes bibliographical references (leaf 28).

The variables affecting the crystalization of sodium metabisulfite

Fri, 01 Jan 1960 00:00:00 GMT

The variables affecting the crystalization of sodium metabisulfite Levine, Gerald M. (Gerald Melvyn); Marshall, David William. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1960; Includes bibliographical references (leaf 32).

Effect of shear on polyisobutylene solutions

Fri, 01 Jan 1960 00:00:00 GMT

Effect of shear on polyisobutylene solutions Koo, George P. (George Ping-Shan) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1960; Includes bibliographical references (leaf 39).

Unsteady flow inefficiencies in partial-admission turbines

Sun, 01 Jan 1961 00:00:00 GMT

Unsteady flow inefficiencies in partial-admission turbines Lucheta, Roger Angelo. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1961; Includes bibliographical references (leaves 28-[29]).

Radial deflections of cylindrical roller bearings

Sat, 01 Jan 1944 00:00:00 GMT

Radial deflections of cylindrical roller bearings Chapin, Edward C. (Edward Canning) Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1944; Includes bibliographical references (leaf 10).

Effect of dynamic loading on bending modulus of rupture of Eastern spruce

Sat, 01 Jan 1944 00:00:00 GMT

Effect of dynamic loading on bending modulus of rupture of Eastern spruce Axon, Donald T. (Donald Thomas); Loesch, Franklin C. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1944; Includes bibliographical references (leaf 18).

Equivalent analog & digital models

Sun, 01 Jan 1961 00:00:00 GMT

Equivalent analog & digital models Lee, Hong Chak Heili. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1961; Includes bibliographical references (leaf 45).

Residual pore pressures and shear strength of compacted clay

Sun, 01 Jan 1961 00:00:00 GMT

Residual pore pressures and shear strength of compacted clay Gulhati, Shashi K. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil and Sanitary Engineering, 1961; Includes bibliographical references (leaf 32).

Cracking and ultimate strength in shear of curved concrete beams reinforced with welded wire fabric

Sun, 01 Jan 1961 00:00:00 GMT

Cracking and ultimate strength in shear of curved concrete beams reinforced with welded wire fabric George, Charles E. (Charles Edward); Wechsler, Michael J. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil and Sanitary Engineering, 1961; Includes bibliographical references (leaf 77).

Determination of the linear thermal expansion coefficients of the refractory carbides by X-ray diffraction

Sun, 01 Jan 1961 00:00:00 GMT

Determination of the linear thermal expansion coefficients of the refractory carbides by X-ray diffraction Cuklanz, Harlan Dale. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1961; Includes bibliographical references (leaf 9).

Solidification structures of aluminum-copper alloys

Sun, 01 Jan 1961 00:00:00 GMT

Solidification structures of aluminum-copper alloys Born, Richard D. (Richard Durrell) Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1961; Includes bibliographical references (leaf 17).

The electron beam welding of molybdenum sheet

Sun, 01 Jan 1961 00:00:00 GMT

The electron beam welding of molybdenum sheet Berman, Herbert Stanton. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1961; Includes bibliographical references (leaf 23).

The acetolysis of the p-toluenesulfonate of 9-hydroxymethyldianthracene

Fri, 01 Jan 1960 00:00:00 GMT

The acetolysis of the p-toluenesulfonate of 9-hydroxymethyldianthracene Tolman, Chadwick Alma. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1960; Includes bibliographical references (leaf 35).

Reactions of some organotin compounds

Fri, 01 Jan 1960 00:00:00 GMT

Reactions of some organotin compounds Sabet, Claude R. (Claude Raymond) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1960; Includes bibliographical references (leaves 21-22).

An investigation of the structure of the dimer of 2,6-dibenzalcyclohexanone

Fri, 01 Jan 1960 00:00:00 GMT

An investigation of the structure of the dimer of 2,6-dibenzalcyclohexanone Rodricks, Joseph V., 1938- Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1960; Includes bibliographical references (leaf 14).

Extraction of trace quantities of cesium : the aqueous tetraphenylborate-nitrobenzene system

Fri, 01 Jan 1960 00:00:00 GMT

Extraction of trace quantities of cesium : the aqueous tetraphenylborate-nitrobenzene system Prussin, Stanley G. (Stanley Gerald) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1960; Includes bibliographical references (leaf 40).

The kinetics of hydrogen exchange between hydroxyl groups of alcohols

Fri, 01 Jan 1960 00:00:00 GMT

The kinetics of hydrogen exchange between hydroxyl groups of alcohols North, Barry J. (Barry Joel) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1960; Includes bibliographical references.

Solids mixing in a fluidized bed

Fri, 01 Jan 1960 00:00:00 GMT

Solids mixing in a fluidized bed Nicholson, William J. (William Joseph) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1960; Includes bibliographical references (leaf 33).

A correlation for relating the friction factor in curved pipe to the friction factor in a straight length of pipe

Fri, 01 Jan 1960 00:00:00 GMT

A correlation for relating the friction factor in curved pipe to the friction factor in a straight length of pipe Kravitz, Lawrence R. (Lawrence Ronald) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1960; Includes bibliographical references (leaf 24).

The effect of a direct current electric field upon acrylonitrile polymerizations at low temperatures

Fri, 01 Jan 1960 00:00:00 GMT

The effect of a direct current electric field upon acrylonitrile polymerizations at low temperatures Kiley, Roger. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1960; Includes bibliographical references (leaf 32).

The production of chlorine and sodium hydrate by the electrolysis of common salt

Thu, 01 Jan 1891 00:00:00 GMT

The production of chlorine and sodium hydrate by the electrolysis of common salt Fiske, Henry A.; Forbes, Howard C. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1891

A survey of steam railway car lighting by electricity

Fri, 01 Jan 1926 00:00:00 GMT

A survey of steam railway car lighting by electricity Klimowicz, Joseph Robert.; Shaheen, Shahady. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1926

A technical high school

Fri, 01 Jan 1892 00:00:00 GMT

A technical high school Francis, Frederick L. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1892

A microprocessor-based processor board for the new 6.115 laboratory kit system

Thu, 01 Jan 1987 00:00:00 GMT

A microprocessor-based processor board for the new 6.115 laboratory kit system Couto, Paul. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1987; Accompanied by 5 folded sheets in pockets.; Bibliography: leaf 54.

Design of a bank and office building

Fri, 01 Jan 1915 00:00:00 GMT

Design of a bank and office building Schoeppe, Edw. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1915

Design and construction of automatic control for creep testing apparatus

Sat, 01 Jan 1944 00:00:00 GMT

Design and construction of automatic control for creep testing apparatus Callahan, John R. (John Richard); Hoss, Robert D. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1944; Includes bibliographical references.

Cable train : a platform for in-situ manufacturing of underground cable

Mon, 01 Jan 2018 00:00:00 GMT

Cable train : a platform for in-situ manufacturing of underground cable Gray, Luke Alexander, author.; Slocum, Alexander H.,; Du, Qi As the demand for and viability of renewable energies has increased, connecting remote power generation stations to demand centers has become more important. High Voltage Direct Current (HVDC) transmission systems offer efficiency and cost effectiveness over long distances, allow for the linkage of incompatible AC grids, and can be immune to telluric currents and aggressive EMP attacks, which all make these systems particularly applicable to connecting to remote renewables. With the current state-of-the-art in HVDC, overhead lines (OHL) are several times cheaper than underground cables (UGC). However, OHLs have security risks and create substantial visual pollution, which has resulted in significant public opposition and lengthy delays in project permitting. Project developers have reluctantly agreed to replace portions of overhead line with underground cable as a concession to these stakeholders. One way to make UGCs more attractive to developers is to reduce cost by locating UGC systems along railroad right of ways. The increased mobility of heavy machines and materials on railroads and the state-of-the-art in railroad construction machinery provide both precedent and process advantages, which make the concept of augmenting railroads with underground cable systems an attractive one. The practice of installing and maintaining such systems could be less complex than traditional methods required by independent transmission corridors. The use of private railways may avoid conflicts with external stakeholders and eliminate the regulatory delays that have plagued many renewable energy transmission projects. Additionally, taking advantage of the increased accessibility of railroads by in-situ manufacturing high voltage, extruded cable in lengths far greater than what is currently able to be transported by road haulage, may reduce overall project costs by eliminating expensive and vulnerable cable splices. To accomplish this, here we present a method for continuously manufacturing and installing high voltage undergourd cable from a moving "Cable Train" using public-private railway systems. There are three primary challenges associated with such a mobile platform -- extrusion, curing, and degassing. Several promising countermeasures have been presented, which require varying levels of further development continuous extrusion, horizontal curing, and inline degassing. Herein, further discussions on standards, system topology, earthworks, practical limitations to cable production length, and cost estimation, can also be found. The technology and methods to accomplish this vision can be achieved by a pre-competitive technology consortium with member companies capable of completing and fully realizing the proof-of-concept designs proposed. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018; Supervised by Alexander H. Slocum. Cataloged from PDF of thesis. Vitae.; Includes bibliographical references (pages 83-86).

Lithium Transport in Monovalent Selective Electrodialysis: Effect of Brine Salinity, Acidity and Composition

Wed, 01 Feb 2023 00:00:00 GMT

Lithium Transport in Monovalent Selective Electrodialysis: Effect of Brine Salinity, Acidity and Composition Thomas, John Lithium is an increasingly important resource for electrification but current supply will not keep up with expected demand. Monovalent selective electrodialysis (MSED) offers a potential method to separate lithium from other elements from salt lake brine. A monovalent selective electrodialysis setup was used to test conditions of pH, salinity, coexisting cations, and current density in the effectiveness in lithium extraction from salt lake brines. MSED of multi-component brines containing more coexisting ions is shown to be less effective than brines with only one coexisting cation. The study shows that pH 7 had significantly higher separation coefficient than lower pH without significant negative impact on current efficiency. The lowest salinity brines of 10 g/L showed the highest separation coefficient, approaching 10 for the Chinese brine, while still having similar current efficiency to the higher salinity brines. Current density is also shown to increase the separation coefficient 3x while only only reducing current efficiency by 50% or less.

Evaluating a reflexive neuromuscular gait model against real-world results

Wed, 01 Feb 2023 00:00:00 GMT

Evaluating a reflexive neuromuscular gait model against real-world results Seelhoff, Carl Andrew The inner workings of human gait are still not well understood. Many models of human gait exist, although no singular model provides insight on human gait behavior and how it alters under disturbances. In an effort to determine if a neuromuscular walking model is capable of predicting human gait under torque disturbances from an ankle-mounted exoskeleton, the results of a prior experiment involving able-bodied subjects with ankle-mounted exoskeletons attached to their feet were recreated in a MATLAB simulation. An optimization-based workflow attempts to reproduce experimental results through selection of optimization objectives based on human gait metrics, producing walking simulations and comparing them with real-world results and establishing a framework which can be applied to future research and analysis. While the optimized simulations do not accurately reproduce human gait as seen in experiments, the gait patterns observed align broadly in some characteristics, and some objective choices produce more convincing results than others. Further testing and more robust statistical analysis is needed to soundly determine whether this model can be predictive of human gait behavior and what minimal set of constraints and optimization objectives is needed to do so.

Rail Wheel Noise in Road to Rail Maintenance of Way Vehicles

Wed, 01 Feb 2023 00:00:00 GMT

Rail Wheel Noise in Road to Rail Maintenance of Way Vehicles Rizo, Theodore Railroads across North America use railgear devices to enable street legal vehicles to travel on the same railroad tracks used by trains. Thousands of these vehicles are used to regularly inspect and maintain the infrastructure that keeps the North American economy running. A common complaint when operating these vehicles when traveling on rail is an excessive wheel noise at 29 MPH. Because this noise only exists at 29 MPH it was determined through testing to be the result of a resonant natural frequency response in the railgear excited by manufacturing irregularities in the rail wheels. To dampen the resonant natural frequency response and improve the operator experience using railgear equipped vehicles manufacturing changes were identified to improve the rail wheels. These changes will improve an operator’s experience when using railgear-equipped vehicles by reducing noise and vibration.

Evaluating Nuclear Energy Power Conversion Cycles for Microreactors

Wed, 01 Feb 2023 00:00:00 GMT

Evaluating Nuclear Energy Power Conversion Cycles for Microreactors Geschke, Miller Microreactors have become increasingly popular in the past decade, but the economics of these technologies has yet to be proven. Analysis is required to support the development of microreactor designs by comparing design choices and predicting costs. A simulation tool was developed which estimates the size and cost of heat exchangers along with the efficiency of three simple power conversion cycles. Printed circuit heat exchangers with semi-circular channels were used in analysis due to their high power densities and low costs, making them extremely suitable for use with microreactors. A stepwise linear solver was implemented for steam generator analysis, while other heat exchangers use the LMTD difference method to compute overall heat transfer area. Heat exchanger analysis tool iterates on channel length to achieve convergence with user-given inputs, before calculating heat exchanger volume and cost. Cycle efficiency calculations are performed using ideal gas relationships for air and enthalpy relationships given turbine and pump efficiencies for water and CO2. An additional capability is included which can estimate the effect of a regenerative heat exchanger in the conversion cycle. A reference design was picked to show the ability of the analysis tool to effectively compare different primary fluids coupled to a steam Rankine, air Brayton, or supercritical CO2 cycle. A sensitivity study on channel diameter was conducted, illustrating the design optimization capability of the tool.

Electromagnetic Steering of Sodium-Seeded Rocket Thrust Plumes: Design & Analysis

Wed, 01 Feb 2023 00:00:00 GMT

Electromagnetic Steering of Sodium-Seeded Rocket Thrust Plumes: Design & Analysis Gershon, Levi This paper explores the use of the Lorentz force to magnetically steer a rocket engine’s thrust plume, creating an off-axis thrust component. The perpendicular force component thus generated, for the sample design used is estimated at 0.002% without sodium seeding, and 3.5% with said seeding. The design of a prototype thruster is undertaken, burning gaseous propane and oxygen, resulting in a combustion chamber, expansion nozzle, and a magnetic circuit to drive the Lorentz steering force. While the predicted unseeded effect is too small to be useful, sodium seeding may be viable on small vehicles or satellites where minimizing overall system complexity is benefited by eliminating otherwise separate attitude control systems.

Modular Plancha Cookstove Design for Capacity Building in Santa Catarina, Guatemala

Wed, 01 Feb 2023 00:00:00 GMT

Modular Plancha Cookstove Design for Capacity Building in Santa Catarina, Guatemala Horowitz, Sylas Indoor air pollution from cooking on inefficient firewood cookstoves and open fires leads to 3.2 million premature deaths every year (World Health Organization, 2022). In Santa Catarina Palopó, Guatemala, women spend much of their time cooking and primarily use wood fuel, which disproportionately exposes them to air pollutants. An efficient, modular, user-friendly cookstove would improve the health, safety, independence, and cooking experience of women in the community while helping families save wood fuel. Through the Guatemala-based non-profit, Link4, women and builders in Santa Catarina co-designed, prototyped, and user-tested a cookstove that could be manufactured locally for community capacity building. A prototype was also produced in D-Lab to evaluate emissions and efficiency through burn testing. The resulting prototype was a horizontal-feed fiber-reinforced concrete rocket stove with perlite insulation and a plancha (flat stovetop), similar to but smaller than traditional Guatemalan stoves. The size and geometry was designed for modularity and portability, allowing multiple stoves to be used in various configurations, and to maximize thermal efficiency. A burn test D-Lab demonstrated a thermal efficiency of 13-14%. A user test in Guatemala found that the stove heated up quickly and reduced fuel consumption but required more tending and was difficult to transport.

An official residence

Fri, 01 Jan 1892 00:00:00 GMT

An official residence Feland, Logan, 1869-1936. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1892

Design for an opera house

Fri, 01 Jan 1892 00:00:00 GMT

Design for an opera house Vining, John F. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1892

Design for a club house

Fri, 01 Jan 1892 00:00:00 GMT

Design for a club house Dennett, Wm. Hartley. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1892

Design for a school of architecture and general studies

Fri, 01 Jan 1892 00:00:00 GMT

Design for a school of architecture and general studies Koch, A. D. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1892

Stamping and amalgamation of a gold-bearing quartz from Nova Scotia with concentration of the pyritic minerals on a true vanner ; Concentration of a low grade copper ore from Butte, Montana

Thu, 01 Jan 1891 00:00:00 GMT

Stamping and amalgamation of a gold-bearing quartz from Nova Scotia with concentration of the pyritic minerals on a true vanner ; Concentration of a low grade copper ore from Butte, Montana Weston, W. H. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1891

A college memorial building

Thu, 01 Jan 1891 00:00:00 GMT

A college memorial building Clement, H. B. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1891

Smelting of a dry silver ore from Butte, Montana

Thu, 01 Jan 1891 00:00:00 GMT

Smelting of a dry silver ore from Butte, Montana Hamilton, Edwin L. (Edwin Lee), 1914-1998. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1891

The true vanner as a concentrator of calumet and hecla by-products

Thu, 01 Jan 1891 00:00:00 GMT

The true vanner as a concentrator of calumet and hecla by-products Favor, G. W.; Haskins, W. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1891

A method of studying the motion of the diaphragm of a telephone receiver

Thu, 01 Jan 1891 00:00:00 GMT

A method of studying the motion of the diaphragm of a telephone receiver Wait, H. H.; Ricker, Charles W. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1891

An acoustic study of the Blake transmitter

Thu, 01 Jan 1891 00:00:00 GMT

An acoustic study of the Blake transmitter Thompson, H. A. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1891

On the least number of vibrations necessary to determine pitch

Thu, 01 Jan 1891 00:00:00 GMT

On the least number of vibrations necessary to determine pitch Maltby, Margaret E. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1891

Experiments upon certain commercial electric meters

Thu, 01 Jan 1891 00:00:00 GMT

Experiments upon certain commercial electric meters Clough, Albert L. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1891

An experimental investigation of the bi-sulphite process of making chemical fibre

Thu, 01 Jan 1891 00:00:00 GMT

An experimental investigation of the bi-sulphite process of making chemical fibre Wilder, Salmon W. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1891; Includes bibliographical references.

Experiments upon the relative effect of burners for fuel and illuminating gases

Thu, 01 Jan 1891 00:00:00 GMT

Experiments upon the relative effect of burners for fuel and illuminating gases Kimball, Herbert S. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1891

On the heat of vaporization of ammonia

Thu, 01 Jan 1891 00:00:00 GMT

On the heat of vaporization of ammonia Holmes, George Alfred. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1891

Plan for widening a stone arch at Pawtucket, R.I.

Thu, 01 Jan 1891 00:00:00 GMT

Plan for widening a stone arch at Pawtucket, R.I. Dill, Howard A.; Heywood, Lincoln C. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1891

A design for a round house

Thu, 01 Jan 1891 00:00:00 GMT

A design for a round house Dunham, L. A.; Stearns, E. B. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1891

Standardized cardinal and gray dyeings

Wed, 01 Jan 1930 00:00:00 GMT

Standardized cardinal and gray dyeings Fell, Ernest M. (Ernest Millward) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1930; Includes bibliographical references (leaves 32-33).

A municipal lodging house for the city of Boston

Sun, 01 Jan 1933 00:00:00 GMT

A municipal lodging house for the city of Boston McClellan, Hugh D. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1933; Includes bibliographical references (leaves 46-49).

The feasibility of operating a light weight, high speed train on the Lehigh Valley Railroad between Wilkes-Barre and New York

Mon, 01 Jan 1934 00:00:00 GMT

The feasibility of operating a light weight, high speed train on the Lehigh Valley Railroad between Wilkes-Barre and New York Carpenter, Floyd R.; Golsan, Page. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1934; Includes bibliographical references (leaf 80).

Viscosity of coke oven gases

Sat, 01 Jan 1944 00:00:00 GMT

Viscosity of coke oven gases Holbrook, Stanley E. (Stanley Earle); Laredo y Caturla, Rafael. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1944; Includes bibliographical references (leaf 25).

The absorption of sulfer dioxide in milk of lime

Sat, 01 Jan 1944 00:00:00 GMT

The absorption of sulfer dioxide in milk of lime Higgins, Harold Bailey.; Meier, Frederick Bronson. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1944; Includes bibliographical references (leaf 49).

Liquid channeling in small packed towers

Sat, 01 Jan 1944 00:00:00 GMT

Liquid channeling in small packed towers Docal, Gonzalo Constantino.; Ufford, Page S. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1944; Includes bibliographical references (leaf 35).

Critical speeds of shafts with overhung flywheels

Sat, 01 Jan 1944 00:00:00 GMT

Critical speeds of shafts with overhung flywheels Bliss, Warren E. (Warren Ernest) Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1944; Includes bibliographical references (leaf 25).

Investigation of a thermoelectric refrigerator with a water-cooled heat dissipator

Sun, 01 Jan 1961 00:00:00 GMT

Investigation of a thermoelectric refrigerator with a water-cooled heat dissipator Lederman, Warren Alan. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1961; Includes bibliographical references (leaf 23).

An investigation on the variation of the pressure distribution for compressible laminar flow in a choked-flow tube due to changes of the back pressure

Sun, 01 Jan 1961 00:00:00 GMT

An investigation on the variation of the pressure distribution for compressible laminar flow in a choked-flow tube due to changes of the back pressure Lazo Gallo, Jorge A. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1961; Includes bibliographical references (leaf 24).

Prediction of tear resistance of some aluminum and steel alloys by small scale tensile tests

Sun, 01 Jan 1961 00:00:00 GMT

Prediction of tear resistance of some aluminum and steel alloys by small scale tensile tests Lane, Charles F. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1961; Includes bibliographical references (leaves 23-24).

Mechanical properties of recrystallized, high purity tungsten and a tantalum-tungsten alloy

Sun, 01 Jan 1961 00:00:00 GMT

Mechanical properties of recrystallized, high purity tungsten and a tantalum-tungsten alloy Blossey, Robert Gates. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1961; Includes bibliographical references (leaf 21).

Aging characteristics of a wrought alloy of the nickel-chromium-aluminum system

Sun, 01 Jan 1961 00:00:00 GMT

Aging characteristics of a wrought alloy of the nickel-chromium-aluminum system Benjamin, John Stanwood, 1939- Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1961; Includes bibliographical references.

Settling of spheres in an oscillating fluid

Sun, 01 Jan 1961 00:00:00 GMT

Settling of spheres in an oscillating fluid Bousman, John H. (John Henri) Thesis: B.S., Massachusetts Institute of Technology, Department of Civil and Sanitary Engineering, 1961; Includes bibliographical references (leaf 30).

An investigation of dendrite-free aluminum alloy solidification

Sun, 01 Jan 1961 00:00:00 GMT

An investigation of dendrite-free aluminum alloy solidification Bardes, Bruce P. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1961; Includes bibliographical references (leaf 16).

Design for a national opera house

Thu, 01 Jan 1891 00:00:00 GMT

Design for a national opera house Lawrence, William Henry, 1868- Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1891

The microstructure of rotary-swaged rod

Sun, 01 Jan 1961 00:00:00 GMT

The microstructure of rotary-swaged rod Bachner, Frank. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1961; Includes bibliographical references (leaf 26).

Programming of Chinese characters for mechanical translation

Wed, 01 Jan 1958 00:00:00 GMT

Programming of Chinese characters for mechanical translation Sivin, Nathan. Thesis: B.S., Massachusetts Institute of Technology, Department of Humanities, 1958; Includes bibliographical references.

A boathouse for the Massachusetts Institute of Technology

Tue, 01 Jan 1952 00:00:00 GMT

A boathouse for the Massachusetts Institute of Technology Schein, Arthur H., 1929-1983. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1952; Bibliography: leaf 40.

A golf and country club, the Charles River Country Club Oak Hill, Newton, Massachusetts

Tue, 01 Jan 1952 00:00:00 GMT

A golf and country club, the Charles River Country Club Oak Hill, Newton, Massachusetts Sack, Bradley T. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1952

A tin can manufacturing plant for Massachusetts

Tue, 01 Jan 1952 00:00:00 GMT

A tin can manufacturing plant for Massachusetts Ong, Eng Hung. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1952; Bibliography: leaf 41.

A fraternity house for the West Campus

Tue, 01 Jan 1952 00:00:00 GMT

A fraternity house for the West Campus Neuschatz, Perry M. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1952; Bibliography: leaf 15.

The replanning of the commercial and civic center of Wilton, New Hampshire

Tue, 01 Jan 1952 00:00:00 GMT

The replanning of the commercial and civic center of Wilton, New Hampshire Myer, John Randolph, 1927-2016. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1952; Bibliography: leaf 44.

A villa

Fri, 01 Jan 1892 00:00:00 GMT

A villa Ingraham, George Hunt, 1870-1950.; Perkins, Frank E. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1892

A design for an armory

Fri, 01 Jan 1892 00:00:00 GMT

A design for an armory Gill, Edward Paddington. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1892

Constraint analysis of radiation-induced amorphizability of zirconate- and titanate-based nuclear wasteforms

Sat, 01 Jan 2005 00:00:00 GMT

Constraint analysis of radiation-induced amorphizability of zirconate- and titanate-based nuclear wasteforms Frame, Gabrielle Lynn. Pyrochlores have long been a target of researchers looking for ceramic materials that remain stable under high doses of radiation. However, its constituent atoms have a drastic effect on how stable the structure is. The focus of this paper is to explain how titanate pyrochlores are on average an order of magnitude less structurally stable than zirconate pyrochlores. This paper explores the effect of the 48f oxygen position parameter on the structural stability of pyrochlore under heavy ion irradiation. Pyrochlores with intermediate position parameters for oxygen in the 48f location are predicted to be most stable. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2005; "June 2005."; Includes bibliographical references (leaves 27-28).

Town hall for a town of several thousand inhabitants

Fri, 01 Jan 1892 00:00:00 GMT

Town hall for a town of several thousand inhabitants Newman, F. E. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1892

Link motion

Mon, 01 Jan 1877 00:00:00 GMT

Link motion Peabody, Cecil H. (Cecil Hobart), 1855-1934. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1877

A systematic method of procedure for the qualitative detection of mercury, gold, platinum, palladium, osmium, selenium, and tellurium

Tue, 01 Jan 1901 00:00:00 GMT

A systematic method of procedure for the qualitative detection of mercury, gold, platinum, palladium, osmium, selenium, and tellurium Robinson, Ralph C. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1901

The organization of a course of study, as a second year subject in the curriculum of architecture, for the correlating of constructive and architectural design

Sun, 01 Jan 1933 00:00:00 GMT

The organization of a course of study, as a second year subject in the curriculum of architecture, for the correlating of constructive and architectural design FitzPatrick, Thomas K. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1933

A hospital for the mentally diseased

Sun, 01 Jan 1933 00:00:00 GMT

A hospital for the mentally diseased Hyzen, Leon. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1933; Includes bibliographical references.

Preparation of strong bleach solutions

Sat, 01 Jan 1944 00:00:00 GMT

Preparation of strong bleach solutions Braendle, Richard O. (Richard Ottmar); Sanders, Frank H. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1944; Includes bibliographical references (leaf 42).

Low cost industrial housing units in India

Fri, 01 Jan 1943 00:00:00 GMT

Low cost industrial housing units in India Rahman, Habibur. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1943

Preliminary design of a satellite-launched manned vehicle for exploration of the surface of the planet Mars

Thu, 01 Jan 1959 00:00:00 GMT

Preliminary design of a satellite-launched manned vehicle for exploration of the surface of the planet Mars Donaldson, Norman L.; Posey, Dennis C.; Talbot, Richard J.; Ward, Dennis K. Thesis: B.S., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 1959; Includes bibliographical references (leaves 80-86).

An experimental investigation of the stresses and strains in iron and steel I beams

Thu, 01 Jan 1891 00:00:00 GMT

An experimental investigation of the stresses and strains in iron and steel I beams Cole, Fred Allen.; Cole, Harrison Irving. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1891

An experimental study of a method of determining the vertical throw in the drivers of a locomotive

Thu, 01 Jan 1891 00:00:00 GMT

An experimental study of a method of determining the vertical throw in the drivers of a locomotive Leland, William E. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1891

The commercial production of oxygen by electrolysis

Thu, 01 Jan 1891 00:00:00 GMT

The commercial production of oxygen by electrolysis Bryant, W. P. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1891

A digest of the literature relating to the separation of the following metals - beryllium, indium, tantalum, titanium, uranium, zirconium

Tue, 01 Jan 1901 00:00:00 GMT

A digest of the literature relating to the separation of the following metals - beryllium, indium, tantalum, titanium, uranium, zirconium Wood, Howard I. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1901

Design for a sewerage system for the western district of the city of Central Falls, Rhode Island - considering the Dexter Street division in detail and a brief sketch of the accompanying sewage disposal plant

Thu, 01 Jan 1891 00:00:00 GMT

Design for a sewerage system for the western district of the city of Central Falls, Rhode Island - considering the Dexter Street division in detail and a brief sketch of the accompanying sewage disposal plant Keene, William F. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1891

Cathodic reduction

Thu, 01 Jan 1903 00:00:00 GMT

Cathodic reduction Martin, W. C. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1903; Includes bibliographical references (leaves 2-12).

A concrete mansion to be built in the South

Fri, 01 Jan 1909 00:00:00 GMT

A concrete mansion to be built in the South Packwood, Lahvesia P. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1909

The preparation of the derivatives of β-alanine

Sun, 01 Jan 1961 00:00:00 GMT

The preparation of the derivatives of β-alanine Emmett, Arthur Fred. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1961; Includes bibliographical references (leaf 23).

Reaction of carbon dioxide and hydrogen in a liquid phase reactor

Sun, 01 Jan 1961 00:00:00 GMT

Reaction of carbon dioxide and hydrogen in a liquid phase reactor Ball, Roger Theodore. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1961; Includes bibliographical references (leaf 40).

A critical analysis of the differences between the operating brotherhoods and the railroads of the nation, arising out of the increasing use of the diesel-electric locomotive

Sun, 01 Jan 1950 00:00:00 GMT

A critical analysis of the differences between the operating brotherhoods and the railroads of the nation, arising out of the increasing use of the diesel-electric locomotive Slater, H. Nelson. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1950; Bibliography: leaf 126.

Dendritic infiltration of a fiber array.

Sat, 01 Jan 1966 00:00:00 GMT

Dendritic infiltration of a fiber array. Coulson, Barbara Jane. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1966; Bibliography: leaf 14.

Microstructural behavior in superplastic lead-tin eutectic.

Sat, 01 Jan 1966 00:00:00 GMT

Microstructural behavior in superplastic lead-tin eutectic. Doyle, Gregory Francis. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1966; Bibliography: leaf 33.

American misperceptions and the Korean War.

Fri, 01 Jan 1971 00:00:00 GMT

American misperceptions and the Korean War. Haggerty, William Michael. Thesis: B.S., Massachusetts Institute of Technology, Department of Political Science, 1971; Bibliography: leaves 47-49.

The electrolysis of hydrochelidonic and adipic acid

Tue, 01 Jan 1901 00:00:00 GMT

The electrolysis of hydrochelidonic and adipic acid Schlesinger, Bart E. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1901; Includes bibliographical references (leaves i-vii).

Comparison of the dry assay with the wet analysis of platinum sands

Thu, 01 Jan 1903 00:00:00 GMT

Comparison of the dry assay with the wet analysis of platinum sands Picard, D. C. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1903; Includes bibliographical references (leaves 2-4).

The electro plating of aluminum

Thu, 01 Jan 1903 00:00:00 GMT

The electro plating of aluminum Strong, H. D. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1903; Includes bibliographical references.

The constitution of lead salts dissolved in ammonium salt solutions

Thu, 01 Jan 1903 00:00:00 GMT

The constitution of lead salts dissolved in ammonium salt solutions Whitcomb, William H. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1903

A study of certain generic and specific tests for organic compounds of order I

Thu, 01 Jan 1903 00:00:00 GMT

A study of certain generic and specific tests for organic compounds of order I Odell, John Ripley. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1903

Use of reactive chrome-complexes for the tanning of leather

Thu, 01 Jan 1953 00:00:00 GMT

Use of reactive chrome-complexes for the tanning of leather Sadowski, Stanley. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1953; Includes bibliographical references (leaf 33).

Solid electrolyte for fuel cell

Thu, 01 Jan 1953 00:00:00 GMT

Solid electrolyte for fuel cell Pohl, Raymond F. (Raymond Frederick) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1953; Includes bibliographical references (leaf 19).

Supersaturation effects on the change of phase in the equilibrium solid [to & from] solid + gas / Donald E. Pickles.

Thu, 01 Jan 1953 00:00:00 GMT

Supersaturation effects on the change of phase in the equilibrium solid [to & from] solid + gas / Donald E. Pickles. Pickles, Donald E. (Donald Edward) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1953; On t.p., "[to & from]" appears as left and right arrows.

The array E (Apollo 17) command decoder tester set.

Fri, 01 Jan 1971 00:00:00 GMT

The array E (Apollo 17) command decoder tester set. Grahek, Paul Matthew. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1971; Lacking leaf 33.

An experimental study of an Edison dynamo

Thu, 01 Jan 1891 00:00:00 GMT

An experimental study of an Edison dynamo Oxford, George H. K.; Palmer, William Irving. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1891

Designing & Manufacturing Powder Skis

Sun, 01 May 2022 00:00:00 GMT

Designing & Manufacturing Powder Skis Sholler, Rebecca Growing up skiing was something I did every weekend with my family. As I got older I got more into racing and learned a lot about the technical aspects of skiing. Since I began studying mechanical engineering it has been a dream of mine to build my own skis. The goal of this project was to build a pair of functional powder skis as well as test and compare the skis to professionally made ones. I began by doing research into the aspects of different types of skis and how they affect skiing. From there I designed the shape and looked into the layering and material composition determining where to acquire all the materials. I began with the wooden core using a CNC machine to perfect it. Then cut out all the necessary layers including fiberglass and PTEX to go into the skis. Along with this I created a mold in order to press the rocker and camber into the ski. I did this step along with some of the design process with my partner Allison King who shares my passion for skiing and is also in the department. We built different skis however the mold design was the same so we used the same one. Once this was built we epoxied the layers and pressed them into the mold. This created the final skis. From there I did vibration testing in order to compare the modes of vibrations of three pairs of professionally made skis to my skis in order to determine how the chatter would feel in our skis compared to others. Through this process I was able to successfully build skis which are somewhat comparable to professionally made skis especially at low frequencies.

The decomposition of hydrogen peroxide vapor on catalytic surfaces

Fri, 01 Jan 1960 00:00:00 GMT

The decomposition of hydrogen peroxide vapor on catalytic surfaces Israel, Lawrence. Thesis: Chem. E., Massachusetts Institute of Technology, Department of Chemical Engineering, 1960; Includes bibliographical references (leaf 44).

Design and Analysis of a Monocoque Chassis for an Electric Formula SAE Vehicle

Thu, 01 Sep 2022 00:00:00 GMT

Design and Analysis of a Monocoque Chassis for an Electric Formula SAE Vehicle MacNeely, Oliver The chassis design of a racecar is fundamental to unlocking the maximum vehicle performance by supporting the applied external loads with a low-mass, high-stiffness structure. Thus far, MIT’s Formula SAE team has developed and utilized welded steel tube chassis designs for their racecars due to their relative simplicity and economy. By taking advantage of the directional stiffness of anisotropic carbon fiber materials, a monocoque design offers a stiffer structure with similar or lower total mass resulting in a high specific stiffness design that out-performs conventional welded designs. This thesis provides a detailed background on chassis design and the necessary design requirements to meet performance targets and competition regulations. Composite laminate designs are proposed and then integrated into a full-chassis structural design that is then analyzed for torsional stiffness in the ANSYS FEM package. Finally, potted insert design and avenues for future development are considered.

A theoretical study of alienation, apathy and anomie

Wed, 01 Jan 1964 00:00:00 GMT

A theoretical study of alienation, apathy and anomie Eyestone, Robert B. Thesis: B.S., Massachusetts Institute of Technology, Department of Economics and Social Science, 1964; Includes bibliographical references (leaves 58-60).

Design of a "talking ball" sensory aid for the blind

Tue, 01 Jan 1963 00:00:00 GMT

Design of a "talking ball" sensory aid for the blind Rothchild, Ronald. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1963

On the mechanics of textile packaging

Tue, 01 Jan 1963 00:00:00 GMT

On the mechanics of textile packaging Marzoli, Pierfranco. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1963; Includes bibliographical references (leaf 44).

A proposed student union building for Boston College

Fri, 01 Jan 1960 00:00:00 GMT

A proposed student union building for Boston College Patterson, Howard A. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1960; Includes bibliographical references (leaves 52-53).

A public library and civic center for the village of Rockville Centre, New York

Fri, 01 Jan 1960 00:00:00 GMT

A public library and civic center for the village of Rockville Centre, New York Niederman, Ted A. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1960; Includes bibliographical references (leaf [60]).

A housing development ; Design of a neighborhood community in Tegucigalpa, Honduras

Fri, 01 Jan 1960 00:00:00 GMT

A housing development ; Design of a neighborhood community in Tegucigalpa, Honduras Padilla Valenzuela, R. V. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1960

An Arts Center for the University of Chicago area

Fri, 01 Jan 1960 00:00:00 GMT

An Arts Center for the University of Chicago area Klawans, Joan R. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1960; Includes bibliographical references (leaf 16).

A municipal center and courthouse for Lexington, Kentucky

Fri, 01 Jan 1960 00:00:00 GMT

A municipal center and courthouse for Lexington, Kentucky Johnson, E. Verner (Ernst Verner), 1937- Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1960; Includes bibliographical references (leaf 25).

The design and construction of a thermoelectric refrigerator

Thu, 01 Jan 1959 00:00:00 GMT

The design and construction of a thermoelectric refrigerator Sargent, Wesson Phineas. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1959; Includes bibliographical references (leaves 33-36).

Study of a Nernst type gas turbine

Thu, 01 Jan 1953 00:00:00 GMT

Study of a Nernst type gas turbine Myers, H. Joseph (Henry Joseph); Polk, John G. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1953; Includes bibliographical references (leaf 57).

Alkaline condensation of ethyl alcohol

Thu, 01 Jan 1953 00:00:00 GMT

Alkaline condensation of ethyl alcohol Pennepacker, Jesse G. (Jesse Goodacre) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1953; Includes bibliographical references (leaf [19]).

A study of the synthesis of sodium carbonyl

Thu, 01 Jan 1953 00:00:00 GMT

A study of the synthesis of sodium carbonyl Mitchell, William J. (William Joseph) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1953; Includes bibliographical references (leaf 39).

The design of a brake mechanism for a portable hospital bed with variable height

Wed, 01 Jan 1992 00:00:00 GMT

The design of a brake mechanism for a portable hospital bed with variable height Vargas, John G. (John Gabriel) Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1992

A simple spectroscopic pollution analyzer.

Fri, 01 Jan 1971 00:00:00 GMT

A simple spectroscopic pollution analyzer. Halperin, John Jacob. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1971; Includes bibliographical references.

Effect of fields on uni-directional solidification of aqueous salt solutions.

Sat, 01 Jan 1966 00:00:00 GMT

Effect of fields on uni-directional solidification of aqueous salt solutions. Eldis, George Thomas. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1966; Bibliography: leaf 14.

Stepping out of line: A systems-thinking, materials-centric approach to designing for sneaker circularity

Sun, 01 May 2022 00:00:00 GMT

Stepping out of line: A systems-thinking, materials-centric approach to designing for sneaker circularity Yan, Leslie Designing for sneaker circularity presents an opportunity to recover material value within an industry that produces 20+ billion pairs of shoes each year. However, the barriers to a circular sneaker economy are reflected in the complexity of sneaker design, as well as the broader system elements dictating the linear model through which shoes have traditionally been produced and consumed. Sneaker circularity can only be realized by addressing the industrial, financial, and social contexts in which a product economy operates. In light of this complexity, the goals of this thesis are twofold. The first is to construct a systematic understanding of the broad, product-oriented challenges facing the development of a circular sneaker economy. Direct insights from those within the footwear industry The second is to build upon this understanding in order to to inform a new ethos for designing sneakers for materials circularity. This holistic approach will be demonstrated through concept and practice through the material lens of a mono-polyethylene sneaker. Novel textile-based techniques oriented towards circular material design and recovery will be explored. This thesis argues that advancing towards a circular sneaker economy will first require taking one step back: to recognize the larger systems picture surrounding the vision of sneaker circularity, as well as to ground their efforts in materials, the foundational currency of any circular product economy.

Ball milling process

Tue, 01 Jan 1963 00:00:00 GMT

Ball milling process Krzepicki, Yagiv. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1963; Includes bibliographical references (leaf 35).

Investigation of germanium in high electric and magnetic fields

Fri, 01 Jan 1960 00:00:00 GMT

Investigation of germanium in high electric and magnetic fields Indreko, Oolep. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1960; Includes bibliographical references (leaves 22-24).

A Police Station, Boston, Massachusetts

Fri, 01 Jan 1960 00:00:00 GMT

A Police Station, Boston, Massachusetts Hughes, John Taylor, 1817-1862. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1960; Includes bibliographical references (leaf 22).

The effectiveness of Plan E government in Cambridge.

Fri, 01 Jan 1971 00:00:00 GMT

The effectiveness of Plan E government in Cambridge. Gottfried, Joel Alan. Thesis: B.S., Massachusetts Institute of Technology, Department of Political Science, 1971; Bibliography: leaves 81-83.

Design for a public bath

Mon, 01 Jan 1894 00:00:00 GMT

Design for a public bath Newhouse, Henry L. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1894

An automobile garage

Mon, 01 Jan 1906 00:00:00 GMT

An automobile garage Logan, Frank. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1906

An investigation of architectural acoustics with an illustrative example : comprising the S.B. thesis

Mon, 01 Jan 1923 00:00:00 GMT

An investigation of architectural acoustics with an illustrative example : comprising the S.B. thesis Reno, Robert Wales. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architectural Engineering, 1923; Includes bibliographical references (leaf vi).

A community dining hall

Tue, 01 Jan 1907 00:00:00 GMT

A community dining hall Darling, Maude Frances. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1907

A Christian Science Church

Mon, 01 Jan 1912 00:00:00 GMT

A Christian Science Church Willis, C. M. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1912

The design of a high-speed slave Brailler for a Braille converter device

Sun, 01 Jan 1961 00:00:00 GMT

The design of a high-speed slave Brailler for a Braille converter device Lichtman, Stuart A. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1961

Reflectance spectra of the Galilean satellites of Jupiter

Sat, 01 Jan 1994 00:00:00 GMT

Reflectance spectra of the Galilean satellites of Jupiter Person, Michael James. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1994; Includes bibliographical references (leaf 43).

Design considerations for improving the control of a dynamics measuring device

Thu, 01 Jan 1987 00:00:00 GMT

Design considerations for improving the control of a dynamics measuring device Meer, David William. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1987; Bibliography: leaves 52-53.

An office building erected by a rail-way corporation

Fri, 01 Jan 1892 00:00:00 GMT

An office building erected by a rail-way corporation Hopkins, Prescott A. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1892

Integrated Microfluidic Culture Media Oxygenator for Organ-on-a-Chip Applications

Sun, 01 May 2022 00:00:00 GMT

Integrated Microfluidic Culture Media Oxygenator for Organ-on-a-Chip Applications Dey Barsukova, Anita Microphysiological systems (MPS) are in vitro platforms for the culture of human cells in a manner that closely mimics the in vivo physiological microenvironment. Oxygen is a key element for maintaining cell viability and function in MPS devices. Thus, this thesis presents the design, fabrication, and testing of a microfluidic oxygenator chip, or "Oxychip", for providing control of oxygen concentration in MPS cell culture media. The oxygenation mechanism of the device features a serpentine fluidic channel that contacts a pneumatic pocket through a gas permeable membrane, to allow for oxygen exchange between the liquid media and the gas in the pneumatic compartment. Additionally, the Oxychip integrates the oxygenator module with an on-board micropump, pressure regulator, culture media reservoir, and oxygen probe interface, in a compact 40 x 25 mm microfluidic chip. To validate the functionality of the device, a series of three experiments were conducted in which oxygen partial pressure within circulating fluid media was monitored using oxygen probes, and rapid deoxygenation and re-oxygenation of fluid media was demonstrated.

A computer simulation of cogeneration plant costs

Wed, 01 Jan 1986 00:00:00 GMT

A computer simulation of cogeneration plant costs Babalitis, Panagiotis Alexander. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1986; Bibliography: leaf 38.

Prediction and filtering of binary sequences

Thu, 01 Jan 1959 00:00:00 GMT

Prediction and filtering of binary sequences Blankenbaker, John Virgil. Thesis: E. Eng, Massachusetts Institute of Technology, Dept. of Electrical Engineering, 1959; Includes bibliographical references (leaf 53).

Present and future uses of aluminum and magnesium in building construction

Fri, 01 Jan 1954 00:00:00 GMT

Present and future uses of aluminum and magnesium in building construction Sherwood, Richard M. Thesis: B.S., Massachusetts Institute of Technology, Department of General Engineering, 1954; Includes bibliographical references (leaves 92-95).

Improvements in Powder Rheometry Through Novel 3D Printed Tools

Sun, 01 May 2022 00:00:00 GMT

Improvements in Powder Rheometry Through Novel 3D Printed Tools Moose, Robert Cody Powders and other granular media are used in a variety of industries, including pharmaceutical manufacturing, 3D printing, food production, construction, and more. As such, understanding the frictional rheological behavior of granular media is of great interest. We present a novel testing paradigm to characterize the rheology of granular media in both the quasistatic and transitional regimes. We introduce a family of 3D printed tools. The main geometry comprises an annular helix formed to smoothly penetrate a powder bed and measure while compressing powder due to the helix shape. To optimize the design, we varied the helix angle from 10° to 35° and blade count from 2 to 6 and tested this range of designs experimentally. In addition, we introduce an aerated cup to optionally aerate and fluidize the powder bed during measurements. Using this method, we report the frictional rheology flow curve of noncohesive glass microspheres for shear rates ranging from 0.53s⁻¹ to 5300s⁻¹, or inertial number I ranging from 6.9×10⁻⁵ to 0.95. We also demonstrate that this form of tool is robust against perturbations from aeration, and that data still collapse to the same measurements for multiple aerated conditions.

Design for a co-operative agricultural settlement in the Negev region of Israel

Tue, 01 Jan 1952 00:00:00 GMT

Design for a co-operative agricultural settlement in the Negev region of Israel Rubin, Laurence L. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1952; Bibliography: leaf 16.

Experimental determination of the structure of shock waves in fluid flow through collapsible tubes with application to the design of a flow regulator

Mon, 01 Jan 1979 00:00:00 GMT

Experimental determination of the structure of shock waves in fluid flow through collapsible tubes with application to the design of a flow regulator Kececioglu, Ifiyenia. Thesis: Mech. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1979; Includes bibliographical references.

Experimental check of Grossers method for finding the sum of the principal stress inside a photoelastic model knowing the boundary conditions

Sat, 01 Jan 1944 00:00:00 GMT

Experimental check of Grossers method for finding the sum of the principal stress inside a photoelastic model knowing the boundary conditions Barclay, Ralph G. (Ralph Gordon) Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1944; Includes bibliographical references.

Studies of the fractional separation of the rare earth elements reaction of the anhydrous chlorides with ethyl benzoate.

Mon, 01 Jan 1945 00:00:00 GMT

Studies of the fractional separation of the rare earth elements reaction of the anhydrous chlorides with ethyl benzoate. Jeffries, Maryruth Claypool. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1945; Bibliography: leaf 29.

Between rigid and soft robotics : discrete assembly of heterogeneous cellular structures

Wed, 01 Jan 2020 00:00:00 GMT

Between rigid and soft robotics : discrete assembly of heterogeneous cellular structures Ochalek, Megan (Megan E.) Traditional robots consist of rigid links and joints to create mechanisms, end effectors, and limbs. Soft robotics is a subfield of robotics which utilizes highly compliant materials to create bio-inspired movement. The field is of high interest at the moment, as it presents new opportunities for adapting and navigating in environments difficult for conventional robotics. Despite these benefits, soft robotics still has some limitations due to the inherent manufacturing challenges of polymeric and elastomeric materials. A recent approach based on discrete assembly of modular lattice components shows promise for scalable construction of tunable material systems. This thesis proposes the use of a tool kit of components to discretely assemble lightweight, cellular structures with spatially programmable anisotropy. This bridges the gap between soft and hard robotics, allowing robots to exhibit both soft and hard characteristics. Starting at the basic building block, this thesis will describe going from 0D to 1D to 2D to 3D structures. Two part types - rigid and compliant - will be used to tune spatial heterogeneity. As a simple case study, I will take an anisotropic beam, and show how analytical, numerical, and experimental characterizations compare. Then, I will study how actuation can be used to provide shape authority over the beam, and compare numerical results with experiments. Through this, I can extract performance metrics relating mass, stiffness, strength, energy, and deflection. From here, leveraging the inherent modularity and hierarchical scaling of discrete lattice systems, I can project performance for larger scale morphing structures, thereby describing a method to combine soft and hard robotics. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from student-submitted PDF of thesis.; Includes bibliographical references (pages 36-37).

Adsorption of ammonia and carbon dioxide in solutions of magnesium sulfate / by Ernest T. Schoenwald, Frank E. Rush, Richard J. McGarry.

Sat, 01 Jan 1944 00:00:00 GMT

Adsorption of ammonia and carbon dioxide in solutions of magnesium sulfate / by Ernest T. Schoenwald, Frank E. Rush, Richard J. McGarry. Schoenwald, Ernest Theodore.; Rush, Frank Edward.; McGarry, Richard J. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1944; Includes bibliographical references (leaf 29).

Removal of light ends from coke-oven light oils

Sat, 01 Jan 1944 00:00:00 GMT

Removal of light ends from coke-oven light oils Alden, Gardner E. (Gardner Evans); Stearns, Thornton. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1944; Includes bibliographical references (leaf 26).

Parallel retrieval algorithms for semantic nets

Wed, 01 Jan 1986 00:00:00 GMT

Parallel retrieval algorithms for semantic nets Baek, Hae Jin. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1986; Bibliography: leaf 61.

Between AB and D : a new class of audio amplifier

Tue, 01 Jan 1985 00:00:00 GMT

Between AB and D : a new class of audio amplifier Granderson, Kenneth Arnold. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1985; Bibliography: leaf [37].

Production control in the Revere Sugar Refinery

Sun, 01 Jan 1922 00:00:00 GMT

Production control in the Revere Sugar Refinery Hall, Reginald Sexton.; Malcolm, Charles Gordon.; Taylor, Charles Herbert. Thesis: B.S., Massachusetts Institute of Technology, Dept. of Business and Engineering Administration, 1922; Includes bibliographical references (leaf 141-143).

A study of the effect of the Hoppes live steam feed water purifier on the composition of the feed water

Thu, 01 Jan 1891 00:00:00 GMT

A study of the effect of the Hoppes live steam feed water purifier on the composition of the feed water Cunningham, Edward. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1891

Efficiency of alternate current transformers

Thu, 01 Jan 1891 00:00:00 GMT

Efficiency of alternate current transformers Vielʹe, Francis Stuart.; Bolan, Thomas Vincent. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1891

Risk based control in uncertain environments

Wed, 01 Jan 2020 00:00:00 GMT

Risk based control in uncertain environments Roudebush, George Imre. Controllers for dynamic robots which regulate around an optimized trajectory often struggle with reliability in uncertain environments, and making control decisions in real-time. Using a map of risk to the robot's state, a risk gradient controller can be created to find paths back to safety from anywhere in the robot's reachable space. Despite generating a variety of complex and dynamic behaviors, this method suffers from sensitivity to sensor and process noise, as the value of risk associated with the robot's state is not well behaved. In order to correct for this sensitivity, a Stochastic Risk Gradient Controller (RGC) and sample-based Extended Kalman Filter (EKF) are proposed. The Sample Based EKF uses pre-simulated dynamics to generate optimal state and uncertainty estimate up to 10 times faster than an online-simulation. The Stochastic RGC then uses those estimates to calculate more robust control actions in real-time. This framework is applied to a model of a pogo-stick robot and simulated with various levels of sensor and process noise. In trials with relatively large measurement noise, the Stochastic Risk Gradient controller succeeded up to 15% more often than the naive risk gradient controller, while failing up to 8% more often in cases when measurement noise was relatively low. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2020; Cataloged from the official PDF of thesis. "Due to the condition of the original material, there are unavoidable flaws in this reproduction. We have made every effort possible to provide you with the best copy available. The images contained in this document are of the best quality available"--Disclaimer Notice page.; Includes bibliographical references (pages 61-62).

Rheological measures of the fracture toughness of hydrogels

Wed, 01 Jan 2020 00:00:00 GMT

Rheological measures of the fracture toughness of hydrogels Will, Carolynn E. Hydrogels are pertinent to many applications, including tissue engineering, contact lenses and drug delivery. However, traditional tensile tests cannot be performed on soft hydrogels due to the soft and sometimes transient nature of their stiffness response. To address this issue, a method is proposed to determine the fracture toughness of a notched hydrogel using rheology, as opposed to tensile tests. Notched polyacrylamide hydrogels underwent constant strain rate tests on a rheometer to fracture the samples. Tensile tests were performed on notched samples as a baseline for comparison. Both tests used hydrogels with varying crosslinker concentration. Rheology tests were performed with varying testing conditions. The hydrogels were created using a Teflon spacer sandwiched between acrylic plates to induce the notch in the sample. Tests were performed with the hydrogel removed from the spacer with mineral oil and also with the hydrogel remaining in the Teflon spacer with mineral oil to reduce abrasion during shear, and finally with the hydrogel in the Teflon spacer without mineral oil. Several different strain rates were tested. A comparison between fracture toughness values obtained from tensile tests and the rheology tests revealed that rheology resulted in similar fracture toughness values. This is a positive indication of the ability to use rheology to measure nonlinear properties of soft materials. Varying the testing procedure is important to eventually determine the optimal way for a soft hydrogel to be tested. In this study, tests performed with the hydrogel in the Teflon spacer resulted in lower fracture toughness and critical strain. A strain rate dependence of the fracture toughness and critical strain was also found for the hydrogel. This information about the response of the materials to different testing conditions will be valuable for testing soft gels using rheology moving forward. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 36-37).

Scalability of carbon-neutral cooling system

Tue, 01 Jan 2019 00:00:00 GMT

Scalability of carbon-neutral cooling system Noh, Christine (Researcher in mechanical engineering). The scalability of a carbon neutral cooling system to provide the MIT campus its annual cooling needs was assessed. The cooling system under observation requires 400 W of electricity mainly to power unidirectional fans that propel air through the chambers and 1423.88 W of hot water to raise the temperature of the airflow in the regenerative cycle. The results of the theoretical energy calculations, based on the annual cooling needs and energy consumption of MIT in the 2017 fiscal year, determined that there is not enough excess hot water supplied by the natural gas utilized by the power plant on campus in order to fully operate enough system units to contribute adequate cooling. MIT requires 207,679,950.191 kWh of energy of cooling annually with an excess of 211 kWh of excess hot water, which is not enough to power the required 101,839 system units necessary to provide total campus cooling, which is 8.45 x 10⁷ kWh of energy. Evacuated tube solar collectors across an area of 181 m² may be able to bridge the thermal energy gap assuming 800 W/m² at 65% efficiency. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 26).

Radiation damage assessment of atomically thin membranes

Wed, 01 Jan 2020 00:00:00 GMT

Radiation damage assessment of atomically thin membranes Parks, Sean M. This thesis investigates the methodologies and results of gas transport across atomically thin membranes, which are relevant to reducing Tritium inventory in fusion reactors by separating Helium from the plasma exhaust stream. A novel experimental apparatus and set-up is devised to measure the gas transport rate across a membrane by containing a pool of liquid water that evaporates over time and passes through the membrane interface to the environment. This device minimizes flow resistance on both sides, allowing for membrane resistance changes to be appropriately assessed. This apparatus also measures less than 5 % error between trials on the same membrane, which can be improved with more data collection for each transport measurement. Graphene is transferred onto high pore density polyimide (-50 nm pore diameter, 6E9 pores cm⁻²) and is imaged with a scanning electron microscope (SEM) to assess graphene transfer fidelity. It is found that graphene coverage (defined as the fraction of the polyimide covered by visibly intact graphene) for samples can be as high as 98% using the transfer method explained in this work. The resulting membranes are irradiated with varying levels of Gallium ion radiation in a focused ion beam machine. It is found that irradiating the sample with ion beam settings of 8 keV acceleration voltage and a dosage of 2.53E+13 Gallium ions cm 2 causes no noticeable change in membrane performance of water vapor transport. Future work will include irradiating the sample at higher dosages and assessing membrane performance while correlating these dosages to what is expected in a fusion reactor setting. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 27).

Computation within the context of mechanical engineering at MIT

Tue, 01 Jan 2019 00:00:00 GMT

Computation within the context of mechanical engineering at MIT Lee, Kyubin (Researcher in mechanical engineering). Computation is undoubtedly playing a significant role in mechanical engineering both inside and outside of MIT, impacting how mechanical engineers approach and solve problems as well as how mechanical engineering is defined and evaluated. This study focuses on how computation is defined within MIT by analyzing input from both faculty and students in Course 2. Responses from faculty were collected by conducting a series of semi-structured interviews with the teaching staff while input from students were collected in a more indirect manner, by analyzing a historical data set of Course 6 classes taken by Course 2 students from 2014 to 2019 and by assessing 107 responses collected from a student survey. Based on inputs from faculty, computation takes various forms inside a Course 2 classroom, functioning as a skillset or a platform for learning and teaching. Student inputs suggest that there is a growing interest in learning various computation tools both inside and outside of their major. While most Course 2 students feel satisfied with their computational experience at MIT, there are still aspects of the Course 2 and Course 6 curriculum in need of improvement. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from the official PDF of thesis. "May 2019."

Design and analysis of the power electronics system for the Lean Operation Rotary Adsorption Cooling System

Tue, 01 Jan 2019 00:00:00 GMT

Design and analysis of the power electronics system for the Lean Operation Rotary Adsorption Cooling System Anwer, Wasay. The Lean Operation Rotary Adsorption Cooling System (LORACS) was developed in order to investigate avenues for more sustainable space cooling systems in the face of the growing threat of global warming. While traditional cooling systems rely on large amounts of grid electricity and a suite of environmentally harmful chemicals, the LORACS instead leverages thermal properties of water and desiccants to create cooling power from low-grade waste heat sources. Although low-grade waste heat comprises of the majority of the LORACS power input, electrical power is still necessary to drive critical system components such as the fans, pumps, and instrumentation equipment. The LORACS system was designed to provide 3.5 kW of cooling with an expected electrical power input of roughly 475 W. Based on preliminary system testing, it was observed that the system produced roughly 2.7 kW of cooling power with 570 W of electrical power. This paper seeks to outline the power electronics selection process for the initial LORACS prototype, as well as consider solutions and alternatives for future system revisions that would result in a higher coefficient of performance. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, September, May, 2019; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 19).

Microstructure of electro-deposited brass

Tue, 01 Jan 1935 00:00:00 GMT

Microstructure of electro-deposited brass Castleman, Jacob Israel. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrochemical Engineering, 1935

Analyzing the effect of pressure drop on flow rate of hot water in the intercoolers assembly of the Lean Operation Rotary Adsorption Cooling System

Tue, 01 Jan 2019 00:00:00 GMT

Analyzing the effect of pressure drop on flow rate of hot water in the intercoolers assembly of the Lean Operation Rotary Adsorption Cooling System Yoon, Jung Yun Susan. The lean operation rotary adsorption cooling system, a novel idea using a readily available low-grade heat and using desiccant wheel to provide a cooling power, was tested this semester. Specifically, this experimental study focuses on the pressure drop of hot water in the two intercoolers that are part of the desiccant wheel module and the flow rate. The measured pressure drop was 1.3 psi, which was close to the calculated value of 1.59 psi and 1.60 psi. There is a great potential for future work on this project as the initial testing results of the overall system were favorable. There were also various limitations of the testing environment that can be optimized in the future. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from the official PDF of thesis. "Due to the condition of the original material, there are unavoidable flaws in this reproduction. We have made every effort possible to provide you with the best copy available. The images contained in this document are of the best quality available"--Disclaimer Notice page.; Includes bibliographical references (page 22).

Geometry and entanglement in AdS/CFT and beyond

Sun, 01 May 2022 00:00:00 GMT

Geometry and entanglement in AdS/CFT and beyond Chen, Chang-Han Holographic duality is the most well-understood non-perturbative framework of quantum gravity that we have. In particular, it has revealed a deep connection between quantum entanglement and the dual gravitational geometry. A semiclassical analysis on geometries has shed insights on the non-perturbative aspects of quantum field theories, some of which does not seem to require an asymptotic anti-de Sitter boundary. This raises the question, “What does the semiclassical gravity actually know, and how?” This thesis aims to approach a very narrow aspect of this question by, first, summarizing developments in the leading order perturbation theory. Then, we make some small advances on generalizing the perturbative framework to geometries beyond AdS/CFT. On the field theory we side, we discuss perturbation theory with irrelevant deformations; on the gravity side, we study cutoff AdS and D3 brane geometry. The result is not conclusive, but we believe that the framework we set up, along with knowledge in the first few chapters, will lead us to a better understanding of what the perturbation theory of semiclassical gravity is actually capable of.

Luminosity functions consistent with a pulsar-dominated Galactic Center Excess

Sun, 01 May 2022 00:00:00 GMT

Luminosity functions consistent with a pulsar-dominated Galactic Center Excess Dinsmore, John T. A new population of millisecond pulsars is a long-standing proposed explanation for the excess of GeV-scale gamma rays emanating from the region surrounding the center of the Milky Way (the “Galactic Center excess”). We examine several simple parameterizations of possible luminosity functions for this population, as well as several benchmark luminosity functions proposed in the literature, and compare the predicted populations of resolved point sources to the Fermi 4FGL-DR2 point source catalog and a sub-population recently identified using wavelet-based methods. We provide general results that can be used to translate upper limits on the number of resolved point sources associated with the excess, and the fraction of the flux in the excess that can be attributed to resolved sources, into limits on the luminosity function parameter space. We discuss a number of important systematic uncertainties, including in the detection threshold model and the total flux attributed to the excess. We delineate regions of parameter space (containing existing benchmark models) where there is no apparent tension with current data, and the number of total pulsars needed to explain the excess is in the range of O(10⁴⁻⁵). In the future, lowered point source detection thresholds could be achieved either by new analysis methods or new data. An order-of-magnitude reduction in the sensitivity threshold (which may already be achieved by novel analyses probing sub-threshold source populations) could hope to resolve more than 30% of the flux of the excess even in pessimistic scenarios.

mARble: a Research-Based Design Process in Educa9onal Technology

Sun, 01 May 2022 00:00:00 GMT

mARble: a Research-Based Design Process in Educa9onal Technology Iwasaki, Ibuki Over the past few decades, an increasing variety of educa9onal technologies, or edtech, have become available. This was especially evident during the height of the pandemic, when most schools became fully reliant on digital learning tools as they took on a virtual format. But edtech is an extremely broad field, encompassing everything from games to learning plaXorms to assessment tools. Moreover, the world of technology is constantly evolving. Where and how does one begin when designing edtech products, especially those that use newer technologies, while making sure that they actually serve their purpose of enhancing learning? This is the main ques9on I seek to address, and to do so, I will be presen9ng a case study of my own research-based edtech design and development process for a simula9on applica9on that introduces physics concepts using augmented reality (AR). In demonstra9ng my own process, I hope to encourage more designs in the future that are grounded in research insights to ensure that they benefit the users that they are intended for - in edtech and beyond.

Evaluating the Time of Emergence of Heat Waves using Different Definitions

Sun, 01 May 2022 00:00:00 GMT

Evaluating the Time of Emergence of Heat Waves using Different Definitions Padalino, Christine M. Heat extremes, such as heat waves, are characterized by human health effects, increased mortality, and ecosystem-wide impacts. Previous studies of heat waves do not define when and where heat wave frequency will be distinguishable from the background frequency of heat waves in the coming century, and previous studies of heat extremes do not analyze how varying the definition of heat waves contribute to emergence. Using daily resolution of 10 CMIP6 era General Circulation Models forced by the SSP2-4.5 warming scenario, we evaluate the frequency of two definitions presented by the Intergovernmental Panel on Climate Change (IPCC) of heat waves in a reference period and in the future climate to determine the “time of emergence”, or the time when the frequency of heat waves becomes perceptibly different from the background frequency. For heat waves that exceed 5°C above the historical climatology, time of emergence is earliest in high latitude regions and is most correlated with the signal. For heat waves that exceed the 90th percentile of the historical climatology, time of emergence is earliest in low latitude regions and is most correlated with the signal to noise ratio. Identifying the time of emergence for the frequency of heat waves can contribute to potential mitigation policies and techniques that are region and time specific.

Point of Use Semi-Batch Reverse Osmosis Desalination Prototype Experimental Validation

Sun, 01 May 2022 00:00:00 GMT

Point of Use Semi-Batch Reverse Osmosis Desalination Prototype Experimental Validation Moya, Janice Water scarcity is undoubtedly a growing problem worldwide. Desalination provides a potential solution to water scarcity by providing water from typically unusable sources (saline brackish aquifers, seawater, or saline surface water), especially to regions that previously did not have reliable access to treated piped water. A range of desalination systems exists, from large seawater distillation plants in Kuwait to home-scale point-of-use (POU) reverse osmosis (RO) purifiers in India. However, current home-use systems produce significant amounts of wastewater, achieve a recovery of 20-30% of the input feed as drinking water, and consume significant energy. Through previous testing and analysis of a POU RO system, it was identified that recirculating brine within a semi-batch configuration with a brine flushing mechanism can potentially achieve 75% or higher recovery ratios. A prototype made from off-the-shelf parts was engineered by a group of graduate students associated with the Global Engineering and Research (GEAR) lab. In the preliminary testing that they performed the prototype demonstrated recovery rates of 75% without affecting production rate and quality. This work aims to design and integrate engineering a data acquisition board with voltage and current sensors, pressure sensors, and flow meters to facilitate autonomous operation; where this is characterized by automated switches between batch production and flush system states to dispose of an empirically derived flush volume based on a derived threshold system operating pressure. This project experimentally defines the conductivity saturation limits for a semi-batch POU RO system prototype and observes the change in recovery ratio as the prototype continuously operates to perform a long-term, lifetime test of an RO membrane.

The THESAN Project: ionizing escape fractions of reionization-era galaxies

Sun, 01 May 2022 00:00:00 GMT

The THESAN Project: ionizing escape fractions of reionization-era galaxies Yeh, Jessica Yuan-Chen A fundamental requirement for reionizing the Universe is that a sufficient fraction of the ionizing photons emitted by galaxies successfully escapes into the intergalactic medium. However, due to the scarcity of high-redshift observational data, the sources driving reionization remain uncertain. In this work we calculate the ionizing escape fractions (𝑓 subscript esc) of reionization-era galaxies from the state-of-the-art THESAN simulations, which combine an accurate radiation-hydrodynamic solver (arepo-rt) with the well-tested IllustrisTNG galaxy formation model to self-consistently simulate both small-scale galaxy physics and large-scale reionization throughout a large patch of the universe (𝐿 subscript box = 95.5 cMpc). This allows the formation of numerous massive haloes (𝑀 subscript halo ≳ 10¹⁰ M⊙), which are often statistically underrepresented in previous studies but are believed to be important to achieving rapid reionization. We find that low-mass galaxies (𝑀 subscript stars ≲ 10⁷ M⊙) are the main drivers of reionization above 𝑧 ≳ 7, while high-mass galaxies (𝑀stars ≳ 10⁸ M⊙) dominate the escaped ionizing photon budget at lower redshifts. We find a strong dependence of 𝑓 subscript esc on the effective star-formation rate (SFR) surface density defined as the SFR per gas mass per escape area. The variation in halo escape fractions decreases for higher mass haloes, which can be understood from the more settled galactic structure, SFR stability, and fraction of sightlines within each halo significantly contributing to the escaped flux. We show that dust is capable of reducing the escape fractions of massive galaxies, but the impact on the global 𝑓 subscript esc depends on the dust model. Finally, AGN are unimportant for reionization in THESAN and their escape fractions are lower than stellar ones due to being located near the centres of galaxies gravitational potential wells.

Design of a Mechanically Divinatory I Ching Split-Flap Display Device

Sun, 01 May 2022 00:00:00 GMT

Design of a Mechanically Divinatory I Ching Split-Flap Display Device Platt, Lauren E. This project centered around the design and modeling of a mechanical split-flap display device with anthropological applications in connections to the I Ching, an ancient Chinese divination technique. The device was designed to be an interactive mechanical system to introduce new perspective on different areas of the user’s life. The ambition of this project was to create a device to breach the conceived boundaries between the mind and the material through deeply human-centered design at the human machine interface. This project served as an experiment in incorporating interdisciplinary perspectives of engineering, design, art, and anthropology to engineer an aesthetically rich, mechanically interesting, and immersive human experience. This work followed a mechanical engineering design process including brainstorming technological solutions, prototyping, and creating a full computer-aided model designed for ease of future manufacturing and production.

A Percolation Model for Boiling and Predicting CHF

Sun, 01 May 2022 00:00:00 GMT

A Percolation Model for Boiling and Predicting CHF Wyttenbach, Minna Z. Boiling is a ubiquitous process in numerous applications, characterized by the heat transfer coefficient (HTC) and critical heat flux (CHF). Exceeding CHF can result in catastrophic failure of a system, making it an important value to understand; however, there is no universal model for predicting it. A recently investigated way to model CHF uses percolation theory, which states that CHF is reached at the percolation threshold. A bubble percolation model is used to visualize and predict boiling performance. The predictions of these models will then be used for characterizing the boiling performance of sandblasted surfaces, for which there are ongoing experiments.

Evolution of Trending Topics in Mechanical Engineering Research Theses

Sun, 01 May 2022 00:00:00 GMT

Evolution of Trending Topics in Mechanical Engineering Research Theses Leon, Sofia Eva As new concepts and technologies emerge, researchers in mechanical engineering have focused on various areas of study. This thesis seeks to understand the evolution of research topics over time and identify which subjects have been favored at different points. To accomplish this goal, the titles of MIT Mechanical Engineering theses were analyzed to measure the frequency with which certain keywords appear each year. Text data from theses published between 1975 and 2021 (inclusive) was collected from two MIT websites using an automated script. Using R, the text data was broken up and processed to count the number of occurrences of a particular word in each year. To account for differences in the amount of available data each year, the annual number of occurrences of a word was normalized by the total number of words that appeared that year. Through this analysis, several interesting trends are revealed. Key words and phrases tend to have small time windows (about 5 to 10 years) where they experience heightened popularity and then see decreased usage. This likely represents a rise in research interest when a technology is novel, followed by a decrease in interest once the technology becomes commoditized or obsolete. Furthermore, we will take a deep dive into trends in manufacturing technologies and explore a case study comparing various manufacturing techniques. We take particular interest in additive manufacturing as the research interest in this topic has grown in recent years.

Coral Reef Flood Protection and Coral Growth Typology

Sun, 01 May 2022 00:00:00 GMT

Coral Reef Flood Protection and Coral Growth Typology Eses, Seif One of the main consequences of our actions as humans is the ever increasing force of climate change and the many natural disasters that come as a result of it. A major threat to the stability of our cities and societies is that of rising sea level and the resulting coastal flooding. A city that has began to think of solutions is the city of Boston, pushing them to form an initiative known as “Climate Ready Boston”. The issue of both coastal and storm water flooding are highlighted by this initiative and are addressed with a proposed solution. This project explores the use of natural buffer systems as a source of knowledge to be applied to a coastal protection typology. The element of nature chosen to be studied in this thesis is the coral and more specifically, how the form and material of coral reefs are able to mitigate the damages of incoming waves as a result of storm surges. The form and materiality of the coral reefs are translated into a modular coastal protection typology that can be applied on any coast. However, the project places the typology on the coast of Dorchester, MA due to the high level of sea level rise and therefore, flooding events that will occur in the short, middle, and longer terms in the region. The area relies on a resilient harbor front to thrive, due to the saturation of the inland zones by residential areas. As a result, protection of the water front access pathways is crucial since they also align with the flooding inundation pathways. Hence, this project zooms in on one of the inundation pathways and places the typology in that region. The aims of the intervention are to not only mitigate flooding, but to also use the materiality of limestone in order to regrow a coral reef in the longer timescale. This in turn helps achieve the goal of increasing biodiversity. This thesis therefore translates a natural system to protect both humans, as well as promote healthier and protected habitats for the betterment of coastal marine life.

Optically Clear FDM Printing

Sun, 01 May 2022 00:00:00 GMT

Optically Clear FDM Printing Pettit, Leah 3D printers are becoming increasingly common in homes and libraries across the country. With it comes a desire to make something, but little direction about what to make. A large percentage of the US population wears glasses, so a project which allows people to 3D print their own glasses would be both meaningful and practical if it can be done using easy-to-learn skills. While there is a single documented example of producing a 3D printed lens with some post-processing, that used SLA printer, which is currently less common, especially amongst individuals. I set out to determine whether this process could be amended for FDM 3D printing or if there is another way to make optically clear lenses with an FDM printer. I discovered that the other traditional smoothing techniques were not sufficient to create a clear surface, but resin coating could result in a fully transparent object. However, further research is needed to determine whether a specific focus can be repeatably created using this method, and it would still require a substantial time investment on the part of the potential user. This makes it a poor early-learning project, but leaves open the potential value to more advanced makers.

Application of Unsupervised Machine Learning for Event Classification

Sun, 01 May 2022 00:00:00 GMT

Application of Unsupervised Machine Learning for Event Classification Kryhin, Serhii We study quark and gluon jets separately using public collider data from the CMS experiment. Our analysis is based on an Open Data dataset of proton-proton collisions collected at the Large Hadron Collider in 2011. We define two non-overlapping data mixtures via a pseudorapidity cut—central jets with |𝜂| ≤ 0.65 and forward jets with |𝜂| > 0.65—and employ jet topic modeling to extract individual distributions for the maximally separable categories. Under certain assumptions, such as sample independence and mutual irreducibility, the extracted “topic” categories correspond to “quark” and “gluon” distributions. We consider a number of different methods for extracting reducibility factors from the central and forward datasets and determine fractions of quark jets in each sample dataset. We also utilize the extracted fractions to reconstruct the distributions of observables for “quark” and “gluon” components, explore the change of topic fraction with the rapidity spectrum, compute the intrinsic dimensionality for each of the topics, and perform a crosscheck by exploring the tagging performance. The greatest stability and robustness to statistical uncertainties is achieved by a novel method based on parametrizing the endpoints of a receiver operating characteristic (ROC) curve. To mitigate detector effects, which would otherwise induce unphysical differences between central and forward jets, we use the OmniFold method to perform central value unfolding. To our knowledge, this work is the first application of full phase space unfolding to real collider data, and one of the first applications of topic modeling to extract separate quark and gluon distributions at the LHC.

Paleomagnetic Constraints on Assembly of the Superior Craton: Results from the 2.72-2.69 Ga Vermilion District of the Wawa Subprovince, MN

Sun, 01 May 2022 00:00:00 GMT

Paleomagnetic Constraints on Assembly of the Superior Craton: Results from the 2.72-2.69 Ga Vermilion District of the Wawa Subprovince, MN Levitt, Zoe I. Paleomagnetism can reveal ancient tectonic motions and identify the processes that regionally overprint magnetizations. We present paleomagnetic data from greenstones in the 2.72-2.69 Ga Vermillion Belt, Superior Craton, Minnesota. The Vermillion Belt has experienced lower greenschist facies alteration associated with volcanic-hosted massive sulfide (VHMS) deposits on the Archean paleoseafloor, as well as weak metamorphism from later reworking events. We isolate four magnetization components: a low-temperature viscous remanent magnetization (VRM) recording the present geomagnetic field, a mid-temperature direction consistent with a ~1.11 Ga Midcontinent Rift overprint, a higher temperature component interpreted to be a 1.78 Ga Penokean overprint, and a high-temperature component that exhibits two clusters in in situ coordinates depending on locality: samples from the southern limb of an anticline host a direction D, I = 165.82°, -70.23° (α₉₅ = 14.4°; n= 2 VGPs), while those from the northern limb host D, I = 198.5°, 78.85° (α₉₅ = 14.0°; n = 5 VGPs). To understand the relative timing of these magnetization directions, we also report results for a 2.69 Ga fold test and baked contact test, a 1.78-1.11 Ga baked contact test, and a conglomerate test. Based on these field tests, we constrain our high temperature component magnetization to either a VMS-related primary thermochemical remanent magnetization at 2.69 Ga, or a 1.78 Ga thermochemical post-orogenic overprint associated with the collapse of the Penokean Orogeny. If primary, our data define a paleopole at 46.85°N/ 84.12°E (α₉₅ = 14.95°; n = 7 VGPs). This would suggest rapid plate motion during the accretion of the Wawa-Abitibi Terrane onto the Superior Craton, suggesting that subduction leading to ribbon continent accretion occurred at a higher velocity than observed in Phanerozoic time. However, more data is required before this motion can be fully confirmed.

Literature Review on Li⁺/Na⁺ and Li⁺/K⁺ Separation Processes Compatible with Multistage MSED/NF Lithium Extraction System

Sun, 01 May 2022 00:00:00 GMT

Literature Review on Li⁺/Na⁺ and Li⁺/K⁺ Separation Processes Compatible with Multistage MSED/NF Lithium Extraction System Vemulapalli, Meghana Demand for lithium, a major battery component, is increasing in the ongoing clean energy transition. To increase potential sources, lithium extraction from geothermal brines is being researched. Extracting Li⁺ from brine is difficult as there are other ions present as well. Mg²⁺ and Ca²⁺ are about the same size as Li⁺, but they can be separated out using membrane-based desalination processes like monovalent-selective electrodialysis (MSED) or nanofiltration (NF). The Lienhard Research Group has developed a multistage MSED or NF system to extract lithium from brine. This system still must address the separation of Li⁺ from Na⁺ and K⁺; this separation increases the purity of the final product. This thesis reviews the literature on the Li⁺/Na⁺ and Li⁺/K⁺ separation processes of solvent extraction (SX) and lithium-composite membranes (LCM). SX is used today in other industrial metal separation processes and has potential in this context; LCMs are still early in technological development. SX literature reveals some promising extractants and process parameters that yield high selectivities S(Li⁺/Na⁺) & S(Li⁺/K⁺) and high lithium recovery rates. Next steps would include evaluating the desired S values, recovery rate values, and costs for the designed system and potentially experimenting with SX systems if those specifications are met.

Evaporative Controls on Convective Adjustment: A Satellite-Based Assessment of Convective Available Energy (CAPE) During Surface Drydowns

Sun, 01 May 2022 00:00:00 GMT

Evaporative Controls on Convective Adjustment: A Satellite-Based Assessment of Convective Available Energy (CAPE) During Surface Drydowns Zhang, Lily N. Changes in surface properties are known to influence weather and climate through interactions between the land and atmosphere. In convective atmospheres, convective available potential energy (CAPE) drives convective adjustment and can lead to precipitation. We study the evolution of CAPE during drydowns, interstorm periods over which evapotranspiration occurs, to understand the impact of evaporative controls on convective adjustment. Our results show that drydown CAPE development varies geographically based on hydroclimate and can also depend on initial soil moisture content and moist enthalpy conditions. The impact of these factors on CAPE can be explained by their effect on evaporation, demonstrating the importance of evaporative controls on convective adjustment and providing a benchmark for understanding the relationship between soil moisture and precipitation.

Investigating the Putative Diagenetic Origins for Neoproterozoic Sponge Steranes

Sun, 01 May 2022 00:00:00 GMT

Investigating the Putative Diagenetic Origins for Neoproterozoic Sponge Steranes Drozd, Juliana K. Living organisms often leave molecular traces in the fossil record and these can provide a lens to understand the history of life on Earth, even when body fossils are not present. One widely discussed molecular fossil, useful for unraveling the record of animal life, is 24-isopropylcholestane (24-ipc). 7KLV µELRPDUNHU¶ LV the C30 hydrocarbon derivative of 24-isopropylidene cholesterol, an uncommon marine sterol that is abundant in some species of demosponges. The hydrocarbon 24-ipc has been identified in many late Neoproterozoic sedimentary rocks and oils and notably earlier than the first uncontroversial sponge fossil spicules. The sponge biomarker hypothesis argues that this Neoproterozoic 24-ipc comes from ancient demosponges, which would have implications for the timing of the evolution of animals as a whole. Despite the sponge biomarker hypothesis having considerable support in terms of the secular distribution patterns of 24-ipc and related molecules, combined with the limited biological distributions of its biological precursor, it has seen numerous challenges. In one example, Bobrovskiy et al. (2021) suggest that the sponge steranes found in the rock record have a diagenetic origin via methyl migrations from and to C29 algal sterols. Here, we examine the suggested diagenetic production of 24-ipc from algal sterols based on geologically plausible diagenesis experiments in order to further understand the preservation pathways of algal sterols. We find that, while 24-ipc can be produced diagenetically from C29 algal sterols, it is only produced sporadically and in minute quantities, making it an unlikely source for the Neoproterozoic sponge steranes.

Analysis of Transient Fog Features on Titan

Sun, 01 May 2022 00:00:00 GMT

Analysis of Transient Fog Features on Titan Romashkova, Elena Saturn’s moon Titan is the only known solar system body other than Earth with an active hydrologic cycle, based on methane instead of water. To better characterize this environment, this thesis examines transient low-altitude methane clouds (hereafter referred to as fogs) that have been observed near Titan’s surface in data from the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini mission. We compile a data set of 19 fog features, expanded from previous studies, and investigate a range of factors that could influence fog formation. We find a tendency for fogs to be observed at high latitudes and primarily in the north, in agreement with modeling of Titan’s humidity. They also show a potential correlation to the locations of methane lakes, with several features that appear to trace shorelines. They may also be preferentially observed in seasons with higher insolation. These results can guide future modeling efforts, as well as continued data collection, to further constrain fog formation mechanisms.

Electro-Mechanical Design and Testing of a Prototype Low-Cost Rheometer

Sun, 01 May 2022 00:00:00 GMT

Electro-Mechanical Design and Testing of a Prototype Low-Cost Rheometer Erni, Makita F. Rheology is a key part of modern society, but the devices used to measure complex fluids are large and expensive, making them unobtainable for individuals or small organizations. This thesis presents the first and second prototypes of an effort to design an accurate but low-cost (<$200) rheometer using fused deposition modeling 3-dimensional printing (FDM 3D printing) and off-the-shelf components. Both designs utilized a cylinder rotating concentrically inside a cylindrical cup of sample fluid. The first prototype used an encoded direct current (DC) motor to rotate at a constant rate while measuring the motor current draw to estimate torque and was able to measure a fluid viscosity standard with η = 100 Pa.s within 17% of the known value. The second prototype used a microstepping stepper motor to rotate at a constant rate while using a loadcell to measure the reaction torque on the cup used to hold the sample and was able to measure a η = 0.1 Pa.s sample within 18% of the actual value. The second prototype was also able to measure viscosity vs shear rate curves for shear-thinning fluids over shear rates from 22.6 to 3.8 s-1 all at a cost less than 0.4% that of a laboratory rheometer (DHR-3; TA Instruments) which was used to obtain the comparison data. Finally, this thesis suggests changes to improve the accuracy and versatility of future designs.

Eliminating Plastic Waste by Transitioning Machine Shop to Produce Its Own 3D Printer Filament

Sun, 01 May 2022 00:00:00 GMT

Eliminating Plastic Waste by Transitioning Machine Shop to Produce Its Own 3D Printer Filament Spitz, Talia As 3D printing becomes more popular, the issue of excess plastic grows. In response, companies and hobbyists have developed recycling systems to turn waste material back into 3D printing filament. In the Laboratory for Manufacturing and Productivity (LMP), students use injection-molding and thermoforming machines, and 3D printers for prototyping. All of these tools generate waste products; LMP throws out barrels of plastic every semester. To better align with MIT’s commitment to fighting climate change, LMP needs to cut down on its excess plastic. Filament extrusion and injection molding testing was conducted to pave the way for the LMP to switch over to recycling its own plastic into 3D printer filament and pellets for injection molding. The experiments were promising and confirmed that LMP has the potential to be a model for other labs looking to be more environmentally friendly. Next steps include sourcing a plastics supplier, filament extrusion system and grinder, as well as setting up plastic storage and documenting the recycling system.

The Design of Post-Disaster Housing Units For The East Boston Community

Sun, 01 May 2022 00:00:00 GMT

The Design of Post-Disaster Housing Units For The East Boston Community Teichner, Nicole A. Climate change poses a significant threat to the communities; over the next 50 years, sea level in East Boston can rise up to 14 feet, contributing to significant inland flooding that will occur unless mitigated by further development of flood pathways. Resultantly, many families will be displaced from their homes experiencing flood damage. FEMA provides temporary post-disaster housing in the form of Manufactured Housing Units (MHUs), often prefabricated off-site and transported to the post-disaster location in need. While these units provide to families basic living necessities for up to 18 months, they can rarely satisfy the specific needs of the community. This design proposes a new housing unit suited to the needs of East Boston. East Boston consists of a high socially vulnerable population, and families rely heavily on their communities and local, family-run businesses. Though the primary unit of this design consists of a one-bedroom 15’ x 35’ backyard unit, the impact lies in how units are aggregated and form shared interior and exterior community spaces. Before assembly, families can choose from a set of predetermined designs for shared interior space, including shared space for child care, laundry, or kitchen. The original units consist of 1-2 beds, though a shared kitchen allows for the creation of more sleeping space for extended families; additionally, a shared kitchen minimizes appliance cost. Upon larger aggregation within parking lots on high ground, the formation of semi-private spaces can serve as small gardens, markets, artisanal shops, bike storage, or outdoor library reflective of many healthy East Boston initiatives. Assembly is from a timber frame fabricated off-site, though design and aggregation of the units is designed to minimize the number of unique frame parts. This reduces both cost of housing and level of skilled-labor required for assembly. Roof structure allows for more light to encourage healing post-disaster, extra ceiling space to double as storage, and for optional placement of photovoltaic panels. At the end of 18 months, these units can be repurposed as affordable housing.

Listening in: An Exploration of Forms for Hearing Aid Design

Sun, 01 May 2022 00:00:00 GMT

Listening in: An Exploration of Forms for Hearing Aid Design Tjan, Janice Motivated to inspire more proactive hearing aid adoption and retention, this thesis explores how to generate new forms for OTC hearing aids. In the process of doing so, the opportunity gap between the success of consumer audio hearables and the lack of proactivity for hearing aid adoption is investigated. Information collected from interviews, surveys and codesign sessions was synthesized into three design considerations: expressivity, versatility, and extensibility. Feedback and critique about existing hearable forms inspired the formulation of a user-centric design method for hearing aid form design and two example implementations of this method are presented.

Lavender@MIT: The Case for an All-Gender Restroom Paradigm on the MIT Campus

Sun, 01 May 2022 00:00:00 GMT

Lavender@MIT: The Case for an All-Gender Restroom Paradigm on the MIT Campus Seaman, Elliott S. L. It is obvious that transgender and gender non-conforming students experience MIT differently than cisgender students – what is less obvious is that one of the biggest differences in experiences stems from, ironically, something universally human: the need to use the restroom. In this thesis, we approach the issue of restroom equity (and inequity) on the MIT campus in three areas, offering a window into how nonbinary students experience MIT’s restroom infrastructure, documenting the history and recent progress around all-gender restrooms at MIT, and showing that MIT students have a vested interest in and thoughts about both all-gender restrooms and institutional restroom design in general. Parts I and II offer an account of my personal journey interacting with all-gender restrooms and all-gender restroom policy and activism on the MIT campus, and culminate with a series of proposed physical interventions and a single renovation to both increase the visibility of all-gender restrooms on campus and to act as a possible example for future single-gender to all-gender multi-stall restroom conversions. Part III widens in scope, and acts primarily as proof that the general student body truly does care about the existence of all-gender restrooms on campus, whether they are transgender/gender non-conforming or not.

MICA: Fluid Flow Over Varying Geometries

Sun, 01 May 2022 00:00:00 GMT

MICA: Fluid Flow Over Varying Geometries Hoffmann, Sarah J. The MICA program attempts to make hands on experiments involving measurement, instrumentation, controls, and analysis broadly available in the form of affordable and portable set-ups. A portable water flow visualization chamber was designed and prototyped for use in fluids courses to enable hands on opportunities in classes that are typically theory based. The initial prototype had a lower flow rate than expected, but was able to generate some flow visuals. Changes are proposed that could make this set-up more refined and helpful in classes at the institute and beyond.

Design and Build of a Hydrofoil Boat

Sun, 01 May 2022 00:00:00 GMT

Design and Build of a Hydrofoil Boat Basinger, Nathan L. To investigate techniques of personal watercraft design and manufacturing, while exploring the functional use of hydrofoils, a small hydrofoil watercraft was designed and built. The hull of the boat is a skiff measuring 14 feet and 5 inches in length and weighing 142 pounds. This hull was designed and built as a platform to support the development of the hydrofoil attachments. The watercraft is powered using a 15-horsepower outboard motor, an Evinrude Super Fastwin 1953, restored for the purpose of this project. Two surface-piercing dihedral hydrofoils were affixed to the hull to provide lift sufficient to raise the main hull out of the water. The dihedral surface piercing foils also provide the height control and roll stability necessary for stable flight. The hydrofoils are removable and thus allow the watercraft to be operated as a conventional personal watercraft when foiling is undesired. Estimates based on the hydrofoil boat design and manufactured components predict a takeoff velocity of 5 knots, with foils at a 6° angle of attack, a flying weight of 566 pounds, and a drag at takeoff of 283 pounds.

Structural limitations of additively manufactured building panels

Sun, 01 May 2022 00:00:00 GMT

Structural limitations of additively manufactured building panels Satterfield, Emily An experimental study on the performance of structural panels designed to serve as roofing and walls in low-cost Costa Rican homes manufactured with additive manufacturing of recycled polymers. Designs were simulated iteratively in Solidworks and performance was measured based on weight, print time, and deflection under loading. Loads were calculated based on standards from the Housing and Urban Development Council and Costa Rican weather patterns. A slicer provided by Oakridge National Laboratory was used to calculate an estimated print time for each design. The results from simulation were then plotted to find an optimal design minimizing weight, deflection and print time. As expected, the optimal roof panel design used a small minimum feature size of 0.2” while maintaining stiffness by maximizing the distance between the outer casing of the panel with a thin i-beam inspired inner structure. The optimal roof panel design was used as inspiration for design iterations of the walls. With the optimal geometry selected from iteration, the designs were then evaluated for printing on the BAAM using the design constraints laid out by ORNL. Strict limitations in terms of possible print path required changes to the geometry of the structure that increased deflection under loading by a factor of 10. Tensile tests in accordance with ISO 527-2 were run on samples of rPET printed on an Ultimaker 2 Extended+ to get the material properties of the plastic depending on print direction. The results of these tests can be used to add rigor to previous Solidworks simulations of the house.

Interactive Procedural Design Exploration for Modular Structures

Sun, 01 May 2022 00:00:00 GMT

Interactive Procedural Design Exploration for Modular Structures Rao, John Huanshuo This thesis presents a grammar-based methodology for generating and evaluating structures that are constructed as aggregations of modular units. Using modular units as a building system can be more efficient for construction and potentially high performing structurally. Most of modular structures today are built in simple stacks which clearly advantages construction efficiency and the structural load transfer. However, other more complex configurations of modules might better address other important design factors such as daylight availability and the creative design intent of the architects. With the goal of expanding the design exploration process for modular structures, this thesis proposes a new methodology that integrates procedural design generation using shape grammars and structural performance evaluation using finite element analysis. Algorithmically, this paper takes inspiration from recent advances in discrete modeling tools. Under the existing frameworks, aggregations can be generated following either stochastic procedures or deterministic procedures. However, using deterministic systems often yields expected results with limited diversity while using stochastic systems does not give designers direct control over the generation process. By controlling the stochasticity of the generation process based on user feedback and performance goals, the methodology proposed in this thesis generates design options that follow specific design intent yet provides unexpected results.

Quantification of Aggregate Formation in Prochlorococcus

Sun, 01 May 2022 00:00:00 GMT

Quantification of Aggregate Formation in Prochlorococcus Hou, Lin (Vivian) Prochlorococcus, a unicellular cyanobacterium, is the smallest and the numerically dominant phytoplankton found in the oligotrophic ocean. Despite being one of the most important primary producers in the ocean, there are many questions regarding its lifestyle. Over recent years, aggregates have been regularly observed forming at the bottom of Prochlorococcus cultures, somewhat resembling macroscopic biofilms formed by related bacteria. This study aimed to investigate and quantify this aggregate formation in Prochlorococcus. Nine diverse strains from two clades, low-light IV (LLIV) and high-light II (HLII), were cultured for this study in order to compare the phenotype between and within ecotypes. The aggregate formation was tracked via hourly time-lapse imaging of Prochlorococcus grown under constant light axenically, and xenically with Alteromonas sp. EZ55, and after environmental stressors of dark incubation, heat shock, and EDTA- addition. An algorithm was developed to measure the size of aggregates over time, as well as to evaluate the density of both these aggregates and the surrounding liquid culture in the tube. While LLIVs generally formed more robust aggregates, this wasn’t universal and varied with strains and conditions. MIT9313 and MIT9301 had the most consistent and robust aggregate formation in these experiments. SB and MIT9215, in contrast, were the least disposed to aggregate formation. Notably, all strains formed aggregates under some conditions. The presence of a heterotroph increased the robusticity of the culture and aggregate formations in all strains. The heat shock, similarly, increased aggregation in all strains by triggering the stress response. Moreover, the size of aggregates grew independently from their density. This suggests that the aggregate formation is regulated by particular signals, which affect the interactions between cells when they join and expand an aggregate. In addition, the formation of a “hole” in the aggregate was observed and may be the result of changes in nutrients and light access for cells at the center of the aggregate. This study provides a preliminary analysis of Prochlorococcus aggregation and reveals many questions to be answered in the future regarding Prochlorococcus lifestyles in the open ocean.

A Theoretical Exploration of the Growth and Stability of Alveolospheres

Sun, 01 May 2022 00:00:00 GMT

A Theoretical Exploration of the Growth and Stability of Alveolospheres Bonavia, Joseph37 An alveolosphere is a type of stem cell derived lung organoid. They have a distinct “balloon-like” structure which resembles the alveoli in human lungs. In recent years, they have become increasingly popular as model systems for disease research and treatment development, especially with the onset of COVID-19. Patients born with a rare mutation on both copies of their SFTPB genes face severe respiratory issues after birth which often lead to poor outcomes. Lung cells derived from the stem cells of patients with this double-mutation fail to form the complex structure indicative of successful alveolosphere development. The tension-dominated nature of this structure reveals that the biology of the formation of alveolospheres is heavily coupled with their mechanics. Therefore, in order to fully understand an alveolosphere’s biology it is essential to understand its mechanics. This thesis outlines a theoretical framework which, in conjunction with targeted experiments, could serve as the basis for a mathematical theory of the development and growth of alveolospheres. Such a theory would provide a better understanding of what needs to go right, and what can go wrong, during alveolosphere development. By extension, this framework offers a path forward towards the discovery of new treatments for genetic and pathological lung diseases that directly affect alveoli.

Robotic Finger Hardware and Controls Design for Dynamic Piano Playing

Sun, 01 May 2022 00:00:00 GMT

Robotic Finger Hardware and Controls Design for Dynamic Piano Playing Castro Ornelas, Ruben Robotic manipulators have traditionally been designed with the industrial world in mind. High degrees of freedom (DOF) robotic hands are starting to enable a new section of tasks like grasping unfamiliar objects with complex shapes, in-hand re-orientation, and even solving Rubik's cubes. This work explores a new kind of task: playing piano. Unlike most common robotic hand objectives, playing piano requires much higher accelerations and control over velocity rather than position. Proper velocity control allows us to play the piano like professionals, with different music dynamics, allowing us to play soft and hard depending on the emotion of the notes being played. To understand the critical factors, constraints, and next steps to creating a full robotic hand for dynamic piano playing, I designed and built several one degree of freedom fingers capable of the high accelerations and velocity control needed for playing the piano using actuators that are appropriately sized for a 10+ DOF robotic hand. With this setup, I was able to consistently play individual notes within 1dB of their respective desired output volume, ranging from -25dB to -4dB, at song speeds of up to 129 beats per minute (BPM). This range is equivalent to playing pianissimo (very quiet) to fortissimo (very loud).

Design and Kinematics of a Dielectric Elastomer Actuated Micro Dragonfly Robot

Sun, 01 May 2022 00:00:00 GMT

Design and Kinematics of a Dielectric Elastomer Actuated Micro Dragonfly Robot Arase, Cathleen Dragonflies fly in a unique way compared to other hovering insects. Soft robotics are used to learn more about their flapping motion. An at-scale dragonfly robot is designed around Dielectric Elastomer Actuators that compress and expand 0.5mm. With this knowledge, MATLAB was used to predict the linkage sizes that control the wing stroke movement. Using the values calculated in MATLAB, Solidworks was used to design a soft robot that mimics a dragonfly’s flight. Motion analysis was then used to map the movements of the robot. This analysis showed an angular wing displacement of 93⁰ in the θ direction. The wing hinge (φ direction) moves 90⁰ on the upstroke and is stopped by a limiting piece to 40⁰ on the downstroke.

Optimizing American Football Kickoffs

Sun, 01 May 2022 00:00:00 GMT

Optimizing American Football Kickoffs Wichman, Claire B. The kicker's goal during a kickoff is to strategically minimize the starting field position of the opposing team. This gives his team an advantage by making it less likely for the opponent to score. To determine the initial velocity and angle that minimizes the field position, an aerodynamic model for the ball trajectory and a biomechanical model for running players was used. The model confirmed that kicking the ball at a higher angle and at a higher velocity is better as long as the ball doesn't go into the endzone for a touchback. Analysis of a specific player revealed that he typically kicks the ball at an angle that is lower than optimal.

Analysis of Alternative Queue Systems in Simulated Amusement Parks

Sun, 01 May 2022 00:00:00 GMT

Analysis of Alternative Queue Systems in Simulated Amusement Parks Megchelsen, Thaddaeus Robert This thesis seeks to analyze the effects of alternative queueing systems on guest welfare in amusement parks. Many parks have implemented these systems, allowing some guests to skip the traditional lines for attractions. This project entailed building an amusement park simulation system, permitting analysis of five common alternative queueing systems. Numerous trials were run across a varied set of facility types. In each system type, the guest access and attraction capacity fractions were varied to gain insight into the systems. Output parameters relating to guest welfare were compared between systems, and extension options for the simulation were provided, leaving room for growth in another iteration of the project.

Design and Construction of a Hydrofoil Watercraft

Sun, 01 May 2022 00:00:00 GMT

Design and Construction of a Hydrofoil Watercraft Nall, Ryan A design project aiming to construct an operational hydrofoil watercraft powered by an outboard engine. The hull of the vessel was constructed of plywood and timber, measuring 14’ 6” long with a 54” beam. A 15-horsepower outboard engine was utilized as the vessel’s power plant. The hydrofoils were arranged into surface piercing dihedral foils and utilized NACA 4412 and NACA 4418 foil cross sections. Documentation of the design and build process was maintained to help destigmatize hydrofoil technology and bring awareness of the benefits hydrofoils possess. Testing of the hydrofoil watercraft occurred on the Charles River. The vessel’s hull demonstrated remarkably accuracy between prediction of the numerically calculated maximum drag and speed values and the experimentally obtained results. The high degree of correlation between the vessel’s hull and its calculated performance indicates a high degree of likelihood of success of the foils once attached to the vessel. Calculations estimate a takeoff velocity of 8.4 knots, requiring just less than 2/3 of the motors rated capacity. More data needs to be collected to adequately study other parameters surrounding hydrofoil technology.

Design & Development of Short Benchtop Welding Positioner

Sun, 01 May 2022 00:00:00 GMT

Design & Development of Short Benchtop Welding Positioner Oke, Mojolaoluwa O. The spindle of a benchtop welding positioner is designed to meet a defined set of specifications. These particular specifications consist of dimensional optimizations for spindle height and thru bore diameter and performance requirements, such as speed. Preliminary static analyses are conducted on the subsystems with the heaviest design consideration to ensure they meet the spindle’s requirements. The design takes into account the spindle’s manufacturability, assemblability, components’ overall cost, bearing protection, grounding cable path, and more important aspects. Ultimately, a welding positioner spindle is designed, and a prototype is manufactured to investigate the outcome of the design.

Application of Natural Language Processing to Unstructured Data: A Case Study of Climate Change

Sun, 01 May 2022 00:00:00 GMT

Application of Natural Language Processing to Unstructured Data: A Case Study of Climate Change Ceylan, Ceylan With the ascension of the Information Age and the widespread use of the Internet, a plethora of knowledge exists apropos of numerous areas of interest. The resurgence of big data and machine learning has brought a high hope that designers can learn from past successes and failures. However, when the available data is in a mixture of textual, numerical or graphical form, then the currently popular deep learning tools cannot be applied directly. The question today is about the ability to represent this heterogeneous form of data and to find the relevant information from a huge depository of data in an efficient manner. My study of data preparation is a part of a big group effort in applying Artificial Intelligence based Natural Language Processing models to large corpora of technical design documentation such as climate change reports, which then enable the retrieval of accurate information via semantic search capabilities. The methodology was able to successfully retrieve suitable answers to the user’s questions without reading hundreds of pages of reports. Additionally, the query process was able to bring up Figures and Tables that provided meaningful context to the answers via associate data-linking during the data reading and embedding process.

Failure Analysis and Casting a Gooseneck for Mashnee

Sun, 01 May 2022 00:00:00 GMT

Failure Analysis and Casting a Gooseneck for Mashnee Brandyberry, Everett The gooseneck of MIT Sailing’s classic Herreshoff sailboat Mashnee recently failed. A failure analysis was conducted, and the failure mode identified. Steps were taken to mitigate this failure in a redesign of the gooseneck geometry, and the subsequent patternmaking, sandcasting, and finish machine was completed.

Optimizing Forced-Air Evaporative Cooling Chambers for Vegetable Preservation

Sun, 01 May 2022 00:00:00 GMT

Optimizing Forced-Air Evaporative Cooling Chambers for Vegetable Preservation Alvarez Perez, Gabriela Forced air evaporative cooling is an emerging approach to help with post-harvest fruit and vegetable storage and preservation. The rapid cooling of produce harvested has been shown to reduce food waste substantially making it a promising area for food waste reduction. This technology will be used by farmers who live in hot arid regions of the world with limited electricity access and would benefit from a cooling chamber that can run off minimal energy and will cool produce quickly. To advance understanding of the technology, a test chamber of the forced air evaporative cooler has been designed and built. This chamber will be used to test key design parameters to understand their impacts on the cooling performance and inform the design of full-scale chambers used to cool produce shortly after harvest. This thesis describes the rationale for the test chamber design as well as information on the application of the test chamber and the testing areas of interest.

A Better Bus Map: How Good Transit Map Design Can Strengthen the MBTA’s Bus System

Sun, 01 May 2022 00:00:00 GMT

A Better Bus Map: How Good Transit Map Design Can Strengthen the MBTA’s Bus System Boccon-Gibod, Alexander (Alexander J.) Greater Boston is poised to radically reimagine its bus system in the coming years. With an ongoing network redesign by the Massachusetts Bay Transportation Authority (MBTA) seeking to create a dense network of high frequency bus lines as well as growing political momentum for fare-free transit spearheaded by Mayor of Boston Michelle Wu, the current moment is an exciting one for the future of sustainable, equitable mobility. Improvements to the bus system have the potential to attract more riders, decrease transportation-related carbon emissions, and increase equitable access to opportunities for marginalized communities. Despite ongoing service improvements, there has been little discussion of visual improvements to the bus system. How will riders perceive and discover a redesigned network? How can historic improvements in bus service be bolstered by systemwide visual cues? A key gap in the MBTA’s otherwise strong brand identity represented by color-named transit lines lies in its printed bus system maps available at bus shelters and online. Visually unifying the transit system is a crucial part of maximizing the benefits of these changes in service. This thesis explores bus map redesign precedents, historical MBTA maps, and transit mapping techniques to reconsider what the MBTA bus system map could be. Guided by two main principles of consistency with the MBTA’s brand and highlighting service frequency, this thesis iterates through different options to arrive at a draft proposal of a new bus map that reframes how the transit system—and broader region—can be depicted and perceived.

Investigating if MLB pitchers are self-selecting for high or low drag balls

Sun, 01 May 2022 00:00:00 GMT

Investigating if MLB pitchers are self-selecting for high or low drag balls Sonner, Jessica The drag coefficient of 4928 batted balls in the MLB in 2019 were measured and matched with 121 pitchers who threw the ball to examine if they are statistically more or less likely to select a high or low drag ball to throw. It was hypothesized that (1) pitchers are routinely selecting for either high or low drag balls, and (2) the regular selection of high drag balls are associated with "better performing" pitchers, or pitchers who have less home runs scored against them, as high drag balls travel less far through the air than low drag balls. However, it was found that pitchers in this data set do not appear to be selecting for higher or lower drag balls, and the average drag coefficient of the balls they select is not correlated with that of higher or lower performing pitching statistics.

Manipulating Stiffness of Biomechanical Systems to Train Muscle

Sun, 01 May 2022 00:00:00 GMT

Manipulating Stiffness of Biomechanical Systems to Train Muscle Thompson, Erik M. A new design for the skeleton of biohybrid robots, millimeter scale soft robots powered by engineered muscle actuators, was developed to provide a binary change in stiffness. Two variations of the design were created, one using elastic 50A resin and the other PDMS. The elastic 50A resin design was fabricated successfully. The design uses a manually placed stiffening beam to create the desired change in stiffness. This would allow for the determination of the effects of training with higher stiffnesses after muscle differentiation. These biohybrid robots provide a test bed for studying engineered skeletal muscle and contribute to potential future applications in tissue engineering and biomechanical devices.

Design of a Resistance-Based High Temperature Liquid Metal Flow Meter

Sun, 01 May 2022 00:00:00 GMT

Design of a Resistance-Based High Temperature Liquid Metal Flow Meter Vawter, Logan Flow rate is a parameter that is vital to measure in high temperature pumped liquid metal systems, yet traditional flow meters are unable to perform at these extreme conditions. As a part of the Atomic Simulation & Energy (ASE) Research Group here at MIT, this research seeks to develop a flow meter able to measure the 1200 ºC pumped liquid tin in their methane pyrolysis system. This paper presents a summary of a literature review of methods for measuring liquid metal flow rate. The most viable method allows flow rate to be determined by a height measurement through Torricelli’s law. While liquid metal surface height can be measured in a variety of ways, this paper explores the use of a resistant-based measurement. After reviewing existing designs, an original simple rod design and temperature-insensitive rod-sheath design are presented. A working prototype of the rod-sheath design is detailed and discussed with an experimental procedure as well as considerations recommended for continued work on this inquiry.

Mobility-Aid Smart Pants with Embedded Harness for Daily Use

Sun, 01 May 2022 00:00:00 GMT

Mobility-Aid Smart Pants with Embedded Harness for Daily Use Chen, Karen Mobility aids help individuals that experience problems with moving around maintain autonomy, and can take many forms such as canes, crutches, walkers, among others. These devices are commonly used among the elderly, as decreased mobility is a natural effect of aging. In fact, mobility aids and gait training, often facilitated through the use of bulky gait trainers, harnesses, and or railings, have great potential to improve patient’s cardiovascular health, blood circulation, and disease prevention. However, gait training is often inaccessible due to the heavy equipment required, impractical to purchase for individual use; giving patients more optionality in their mobility aids through everyday wearables could improve the overall health of the mobility-aid user population. In particular, smart garments can adapt to the user and the user’s environment. These harness-embedded pants come into play as the pants are physically connected to the walker, so the harness effectively prevents the user from sustaining a potentially life threatening injury, while discreetly disguised as a regular pair of pants.

Modeling Outdoor Air Pollution and the Urban Form

Sun, 01 May 2022 00:00:00 GMT

Modeling Outdoor Air Pollution and the Urban Form Stamler, Natasha Lia As cities continue to grow rapidly, air pollution is becoming an increasing health problem. However, air pollution’s spatial and temporal variability make it difficult to quantify, even with field measurements. Models are thus useful to understand how pollutants interact with the built and natural environment. Computational fluid dynamics (CFD) offers the highest spatial and temporal resolution for aerial pollutant dispersion modeling within dense urban environments such as urban canyons. An open-source platform such as OpenFOAM is valuable as it can be fully customized for the varying intricacies of urban airflow and is accessible to a wide audience. This thesis develops a solver for aerial pollutant transport by adding a passive-scalar transport equation to buoyantBoussinesqPimpleFoam, the OpenFOAM transient solver for buoyant, turbulent flow of incompressible fluids, with Reynolds Averaged Navier-Stokes (RANS) turbulence modeling. It then demonstrates that this solver can be applied to cases, such as that of an urban canyon, with geometry generated parametrically using Grasshopper, a design tool commonly used by architects and urban designers. The successful implementation of this solver could enable future integration into a streamlined Grasshopper tool that allows designers to easily evaluate the impacts of their designs on urban air pollution during the design process.

Experiments and Design Considerations toward a Novel Continuous Flow Aluminum Fuel Reactor for Underwater Vehicles

Sun, 01 May 2022 00:00:00 GMT

Experiments and Design Considerations toward a Novel Continuous Flow Aluminum Fuel Reactor for Underwater Vehicles Rolfness, Zachary S. Presented here is experiments and design consideration toward the development of an activated bulk aluminum slurry and liquid water reactor. Previous work has shown successful activation of bulk aluminum for 99% successful oxidation with water. However, this reaction has only been seen in bulk reactors with only a bit of progress toward slurry reactors Several experiments were conducted over the semester. The results for high-pressure activated aluminum showed a positive correlation between initial pressure and reactivity. This trend held for both experimental results for the BB form and the slurry form. Experiments on the development of a homogenous slurry showed that a higher shear rate mixer and double the amount of fumed silica were needed to produce a homogenous non-clumping aluminum slurry. Lastly, pumping experiments, unfortunately, showed that in its current state, the fuel cannot be reliably pumped due to the settling of the aluminum inside the piping. Solutions are discussed to overcome the issues seen while pumping. Among other contributions, a theoretical reactor design is presented that hopes to eliminate issues with jamming seen during experimentations. Future hope is that with the contributions found in this paper, further work can be done to successfully engineer a continuous flow aluminum slurry reactor for a wide array of applications.

Design and Manufacturing of a Lead Screw Robotic Gripper

Sun, 01 May 2022 00:00:00 GMT

Design and Manufacturing of a Lead Screw Robotic Gripper Paul-Ajuwape, Kolade Alexander Robotic grippers have many amazing uses. From helping to rescue trapped animals underwater to holding surgical tools in precise locations during an operation, robotic grippers have proved to be useful for many functions that are tedious, dangerous and difficult for the human hand to perform. The MIT MRL needs a robotic gripper to attach to a rotating shaft for a current project that is being worked on. The addition of this gripper as an end effector to the system can provide unique data that will be informative for real world mechanical systems. This thesis provides a review of a range of different robotic grippers through their history and explains the uses of different robotic gripper and have they have developed over time. Looking at two specific case studies the paper collects advantages and drawbacks of the two grippers and identifies the most important factors to take into account when designing a gripper. Using this information, a gear operated gripper is designed and its features are briefly discussed. Based on the drawbacks of the original gripper design a lead screw gripper is designed and then a prototype is manufactured. The process of manufacturing found that the gripper can be assembled by hand, it is strong and articulates smoothly. The drawbacks with the design are mainly from the size of the body and the difficulty with press-fitting between a 3mm aluminum shaft and its bearing. The prototype worked effectively to grip the shaft; however, the gripper could be improved in order to be stronger and articulate even smoother.

Designing & Manufacturing Free-Ride Skis

Sun, 01 May 2022 00:00:00 GMT

Designing & Manufacturing Free-Ride Skis King, Allison Growing up as a passionate outdoorswomen and now an engineer, I have always loved to do two things: skiing and building things. As such, it only felt natural that for my undergraduate thesis, I should attempt to build a pair of skis and see how close I could come to creating professional grade skis. To do this, first a detailed design of a freeride/powder ski was created. From there, and with lots of learning and guidance in the machine shop, a pair of skis and a press were manufactured. When it was all said and done, the skis looked like skis; albeit homemade skis but skis nonetheless. There were clear areas for manufacturing processes improvements that would have improved the physical appearance of the skis but also would have decreased the risk of delamination of the skis. However, to understand how close my skis got to professional grade skis, an experiment was designed to measure the modes of vibrations of several different types of skis to be able to characterize ski behavior. When analyzing and comparing my skis to professional skis, the nose, which accounts for in theory over 80% of energy absorption in skis, compared very closely to that of professional skis. The peaks happened in comparable places, with comparable amplitudes. However, the tail demonstrated abnormally high amplitudes in their key frequency zones. While this is likely a result of our skis having a lack of bindings unlike other skis tested, this could also indicate some issues in layering and manufacturing of the skis. However, the only way to fully know is to test them out on a mountain. So in 7-8 months, the on snow ski testing can validate which one it is!

Nonlinear Amplification of Extreme Climate-Carbon Cycle Events

Sun, 01 May 2022 00:00:00 GMT

Nonlinear Amplification of Extreme Climate-Carbon Cycle Events Vanegas Ledesma, Amanda The geological records of carbon cycle change present significant disruptions at intermittent times, which are often associated with events of abrupt climate change. Despite the variety of mechanisms driving these fluctuations, different disruptions present common characteristics. Through this work, we describe time series analysis methods that allow us to study disruptions in the carbon cycle in a general manner. Our analysis suggests that nonlinear amplifications have contributed substantially to many past climate-carbon cycle disruptions. The study of the mechanisms driving these disruptions becomes an valuable case study for the evolution of human-driven climate change. Better understanding these feedbacks within the carbon cycle would provide insights into the response of the Earth system to the increase of concentrations of carbon in the atmosphere driven by human activity.

An In-Depth Review of the History of the MIT HAUS Team

Sun, 01 May 2022 00:00:00 GMT

An In-Depth Review of the History of the MIT HAUS Team Palacios, Lynda V. Shelter insecurity is a problem that affects people globally, with the United Nations estimating that 1.6 billion people lack access to adequate shelter. The MIT HAUS research group was founded with the goal to create sustainable and affordable housing out of recycled plastics. This will be done using large-scale additive manufacturing and microfactories for distribution of homes. HAUS has been running for 3 years, since the beginning of 2019. The project has been worked on by many people and research has been done on a variety of areas. This thesis presents a cohesive review of the progress HAUS has made over the past three years, discussing any gaps in the existing research, and suggestions on the research to prioritize in the immediate future. The work is split into three main categories: design, materials, and manufacturing. There are two main gaps in the current work done by HAUS. The material properties of rPET are not yet known with enough certainty to determine if it is safe to use in housing. Additionally, there is not enough knowledge on how the anisotropic nature of 3D printing may affect the structural integrity of the home. These two areas should be prioritized for future work.

Tool Carousel to Support Agricultural Rover Soil Testing

Sun, 01 May 2022 00:00:00 GMT

Tool Carousel to Support Agricultural Rover Soil Testing Bick, Amber A tool carousel was designed and fabricated to meet the needs of an agricultural rover autonomously conducting various field tests. The carousel was designed to meet high precision and reliability needs with relaxed speed and space constraints. The carousel is about the size of the rover. It can hold twenty tools at a time that can be up to 1 kg each. The rover can approach the carousel from any direction and will direct the carousel to do a 30 s homing procedure with the intent to then exchange tools. The primary sensors are the Intel RealSense 435i camera and the tool-detecting current sensor both established on the rover, as well as limit switches for tool detection on the carousel. With polished fabrication and completed code implementation, the tool carousel will be fit for field testing.

Applications of Investment Casting as a Manufacturing Process for Injection Mold Tooling

Sun, 01 May 2022 00:00:00 GMT

Applications of Investment Casting as a Manufacturing Process for Injection Mold Tooling Wine, Lila N. An exploration in the utility of investment casting aluminum molds for small-scale plastic injection molding, compared against traditional machining methods for these molds. The intention of this study was to determine if lost wax casting could provide a more efficient option for tool manufacturing. Complex patterns were designed and 3D printed using castable resin, following manufacturers specifications. Various parameters throughout each step of the casting process, such as part design, 3D print settings, and investment procedures were altered to determine their effect on the end result. In the end, more time is necessary to achieve the desired results given the resource limitations of this study. Investment casting could still be a viable option for this type of tooling, given adequate time and resources to optimize each parameter and create a highly repeatable process.

First Order Thermal Model of the Navy integrated Power Electronics Building Block

Sun, 01 May 2022 00:00:00 GMT

First Order Thermal Model of the Navy integrated Power Electronics Building Block Lietch, Ethan To accomplish the United States Navy’s goal of developing a fully electric warship, it is essential to cool critical electronic components within the Navy integrated Power Electronics Building Block (iPEBB) for it to function at its full capacity. The current study develops a first order analytical understanding of the most prolific heat transfer modes within the iPEBB and identifies critical constraints for the design of future cooling systems. The main heat loads within the iPEBB are the rows of MOSFET switches generating 4752 W of waste heat and the transformer which generates 858 W through the outer protective wall. The analysis presented in this thesis defines the critical temperatures and heat fluxes of the critical heat generating sources and can be used as a benchmark for future thermal cooling design.

Design of a small steam-electric power plant

Fri, 01 Jan 1943 00:00:00 GMT

Design of a small steam-electric power plant Holt, James. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1943; Includes bibliographical references.

The effect of accelerated ageing on the corrosion resistance of sheet duralumin

Tue, 01 Jan 1935 00:00:00 GMT

The effect of accelerated ageing on the corrosion resistance of sheet duralumin Brooks, Carson L. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrochemical Engineering, 1935; Includes bibliographical references (leaf 36).

Determining the key of a melody

Tue, 01 Jan 1985 00:00:00 GMT

Determining the key of a melody Hill, Thomas (Thomas W.) Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1985; Bibliography: leaf 42.

An investigation of the stresses in spruce headers

Fri, 01 Jan 1892 00:00:00 GMT

An investigation of the stresses in spruce headers Burnham, H. A.; Fuller, Charles E. 1871- Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1892

A theoretical approach to the journey to work

Tue, 01 Jan 1952 00:00:00 GMT

A theoretical approach to the journey to work Ranyak, John A. (John Andrew) Thesis: B.C.P., Massachusetts Institute of Technology, Department of City and Regional Planning, 1952; Includes bibliographical references (leaf 47).

Design of apparatus for threaded part mating experiments

Thu, 01 Jan 1981 00:00:00 GMT

Design of apparatus for threaded part mating experiments Ranyak, Paul Stephen. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1981; Vita.; Includes bibliographical references.

A surficial geology map of Quincy, Massachusetts

Wed, 01 Jan 1964 00:00:00 GMT

A surficial geology map of Quincy, Massachusetts Reed, Donald E. Thesis: B.S., Massachusetts Institute of Technology, Department of Geology and Geophysics, 1964; Includes bibliographical references (leaf 22).

A wide-range analog to digital converter

Tue, 01 Jan 1980 00:00:00 GMT

A wide-range analog to digital converter Gussow, Seth James. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1980

Solution of LaPlace's equation by Monte Carlo method

Thu, 01 Jan 1959 00:00:00 GMT

Solution of LaPlace's equation by Monte Carlo method Colina Marie, Miguel L. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1959; Includes bibliographical references.

Optimizing the performance of solar-powered absorption cooling systems

Tue, 01 Jan 1980 00:00:00 GMT

Optimizing the performance of solar-powered absorption cooling systems Hainsworth, Eugenie. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1980; Bibliography: leaf 38.

Design and testing of a rotating cryogenic check valve

Tue, 01 Jan 1980 00:00:00 GMT

Design and testing of a rotating cryogenic check valve Hamkins, Christopher P. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1980; Includes bibliographical references.

Digital watt-meter

Tue, 01 Jan 1980 00:00:00 GMT

Digital watt-meter Haltmaier, Richard G. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1980; Includes bibliographical references (leaf 44).

Effect of different annealing times on the microstructure of a dual-phase steel

Tue, 01 Jan 1980 00:00:00 GMT

Effect of different annealing times on the microstructure of a dual-phase steel Hammerman, Evan Joseph. Thesis: B.S., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 1980; Includes bibliographical references.

Evaluation of the Relative Neutronic Risk of Alternative Fusion Fuels

Tue, 01 Feb 2022 00:00:00 GMT

Evaluation of the Relative Neutronic Risk of Alternative Fusion Fuels Jerkins, Joseph The radiological risk profiles of a variety of fusion fuels were assessed, to aid understanding of the influence of fuel choice on the safety and cost of future commercial fusion power plants. Shielding thickness and activation dose rates were modeled for five fusion fuels consisting of Deuterium-Tritium, Deuterium-Deuterium, Deuterium-Helium 3, Deuterium-Lithium 6, and Hydrogen-Boron 11. Simplistic shielding and activation models were carried out in standardized 500MW reactors.

Mini Cheetah Sensor Suite for Visual Perception

Tue, 01 Feb 2022 00:00:00 GMT

Mini Cheetah Sensor Suite for Visual Perception Papalia, Lillian C. The mini cheetah robot is a small lightweight quadruped capable of dynamic movements. Currently, the mini cheetah does not have a method of collecting stabilized perception data. Research has been conducted at the University of Michigan, where a sensor suite for collecting perception data has been created. While the sensor suite is able to collect perception data, it is heavy and affects the agility of the mini cheetah robot and does not incorporate any active stabilization into the design. A lightweight sensor suite was designed and manufactured incorporating a commercial gimbal. Three tests were conducted on a rigid mounted camera and a gimbal stabilized camera. AprilTag detection as well as visual qualitative analysis determined the rigid mounted camera performed better than the current gimbal configuration. Further work involving active stabilization will be needed to determine a satisfactory solution, particularly when the mini cheetah is pronking.

Design of a Deformable Spherical Robot

Tue, 01 Feb 2022 00:00:00 GMT

Design of a Deformable Spherical Robot Lee, Nathaniel Justin The design of a uniquely actuated point-supported spherical robot is investigated to support the claim that deformable spherical robots that are point-supported can increase the speed of the robot. The spherical robot design investigated in this thesis has a unique actuation system because it uses a low number of actuators with the goal of increasing average speed and reducing weight. The most relevant design requirements for this robot were to follow a 40cm/s trajectory and weigh 10 kg or less. The overall design to meet these design requirements and others is discussed and is further explained how the proposed robot functions. A dynamic model was developed to determine a control system for the robot, and to verify the design. The robot was modeled in Simulink using this control system to determine if the 40 cm/s was feasible and to determine if the selected actuators meet the simulated torque and speed requirements. The torque and speed requirements were higher than anticipated for some of the selected actuators in the design presented in this work. When point-supported, the robot was able to follow 40 cm/s circular trajectory in a Simulink model. The robot was also modeled without the parts that make it point-supported, so that a comparison could be made between the two configurations. The robot in the configuration that was not point-supported followed the trajectory much more slowly, supporting the claim that point-supported deformable spherical robots can be faster.

MIT SoFi: A Study in Fabrication, Target Tracking, and Control of Soft Robotic Fish

Tue, 01 Feb 2022 00:00:00 GMT

MIT SoFi: A Study in Fabrication, Target Tracking, and Control of Soft Robotic Fish Williamson, Robert This thesis examines the continuation of the MIT SoFi project by exploring the development of a new fabrication process and implementation of a target tracking algorithm. A new fabrication process to increase the consistency and quality of silicone fish tails using advance silicone molding techniques was explored and included material selection, process redefinition, fabrication, and testing. Two different silicone materials were used and evaluated using video analysis in Logger Pro. A target tracking control algorithm using computer vision and a particle filter was deployed in simulation and tested using recorded data from real SoFi experiments. The hardware and software challenges will be discussed and the proposed solutions will be evaluated. The combination of a consistent fabrication procedure and increased target tracking capabilities opens the door to fabricate a school of SoFi's and carry out robotic swarm operations in the future.

Estimating H₂ production and storage cost targets for cost-competitively meeting electricity and H₂ fuel demand in deeply decarbonized electric power systems

Tue, 01 Feb 2022 00:00:00 GMT

Estimating H₂ production and storage cost targets for cost-competitively meeting electricity and H₂ fuel demand in deeply decarbonized electric power systems Anderson, Eva In order to address carbon emissions from the electricity sector, we must reduce our reliance on fossil fuels to power the grid. Renewable energy produced from solar and wind presents one part of the solution, but energy storage is critical to combat the intermittency of these renewable resources. Currently deployed storage solutions such as hydropower and lithium-ion batteries face certain limitations, and hydrogen storage offers one potential alternative. Along with other members of the Trancik Lab at MIT, I set out to study how renewables-powered-hydrogen production could be utilized as a long duration storage technology in renewables-dominated electricity systems in the future. This question requires systems-level modeling, and I was responsible for much of the early-stage development necessary to build the model. I developed the logic for the hydrogen-plus-electricity system operation, completed a literature review to understand the power and energy capacity costs of hydrogen production, hydrogen storage, and hydrogen-to-power technologies, and modified an existing Trancik Lab model to accommodate the specifics of hydrogen storage. My work will help enable simulations and cost estimates of an energy system that combines electricity production, hydrogen fuel production, and hydrogen storage with hourly resolution on a 20-year system lifetime.

Strengths and Challenges of Mechanical Design Processes in a Federally Funded Research and Development Center

Tue, 01 Feb 2022 00:00:00 GMT

Strengths and Challenges of Mechanical Design Processes in a Federally Funded Research and Development Center Avila, Mariana Sofia Compared to product design processes, design processes for research and development (R&D) are usually less structured, and there is less literature about them. The lack of structure can lead to a lack of clarity or processes that are not well-defined. This research uses a not-for-profit company operating a federally funded R&D center as a case study for mechanical design processes in R&D. Subjects in the mechanical engineering department of the company were interviewed to learn more about the successes and challenges of their design processes. Results demonstrated the effects of the team structures, sponsored vs. internal work, interdisciplinary teams, different management and design techniques, and challenges with planning and executing timelines for design in R&D. The suggestions and conclusions that arose not only provide insights for the company involved but for any organization involved in R&D. Despite the uncertain nature of the work, R&D teams can incorporate a level of structure in their design processes to increase their efficiency and chances of success.

Evaluation of Textile Force-Sensitive Resistors in Quantifying Athletic Shoe Fit

Tue, 01 Feb 2022 00:00:00 GMT

Evaluation of Textile Force-Sensitive Resistors in Quantifying Athletic Shoe Fit Light, Lydia Gaulding A well-fitting shoe is valuable for many reasons, ranging from daily comfort to prevention of injuries. It is no surprise that a good fit is a driving factor in consumer purchase decisions, and is thus highly prioritized by shoe companies. However, ensuring consistent sizing and fit between shoes of varying shapes, layouts, and materials is challenging. Shoe companies use feedback from volunteer fit testers to adjust the design of new shoes before final production, but this process is time-consuming and provides only subjective information. There is need for a sensor-driven method for shoe companies that can provide accurate and objective data about the fit of a shoe. There is extensive research on the value and methodology of quantifying shoe fit. Current approaches use dimensional comparison of foot and shoe shapes. However, this technique has its limitations, considering that both the shoe and foot deform differently based on shoe material and shoe-foot alignment. Ideally, fit would be measured when someone is wearing the shoe. There is precedent in research studies for measuring shoe-foot contact pressures with plastic thin-film pressure sensors and using this to successfully quantify shoe fit. However, the physical properties of plastic thin-film sensors are limited and the testing procedure for the sensors used in the studies does not translate well to an industry R&D setting. Instead, this paper investigates the design and use of textile pressure sensors for measuring shoe-foot contact pressures. Textile pressure sensors have been used in embedded socks for measuring plantar pressure in the research of gait analysis, but there is no literature yet on measuring upper foot pressures with textile pressure sensors for shoe fit analysis. A design is proposed for a sensor system with textile pressure sensors that could be used in a shoe company to evaluate shoe fit. The sensor component specifically was investigated further with four prototypes of textile sensors – two prototypes were made with Amradield Stretch conductive fabric, and two were made with Adafruit Knit Jersey fabric; one prototype of each fabric was constructed with 2 ply conductive thread, while the remaining two used 3 ply. The four sensor prototypes were tested with a voltage probe in a voltage divider circuit using standardized weights. Pressures of 20-350 kPa were applied in long-term (45 sec) and short-term (10 sec) tests, and the sensor outputs were evaluated on precision, accuracy, range, and temporal consistency. All four sensors demonstrated the expected inverse relationship between applied force and resistivity and had an adequate range and temporal precision for testing shoe fit. The results indicate that sensors made of Amradield Stretch performed better in accuracy and precision. There was no significant difference in sensor performance between those with 2 ply and those with 3 ply conductive thread.

Researches in relation to cable telephony

Fri, 01 Jan 1886 00:00:00 GMT

Researches in relation to cable telephony Stebbins, Theodore. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1886

An experimental investigation on the relation of the heat-of-solution of dissociated substances to the effect of temperature on their solubility and dissociation

Tue, 01 Jan 1901 00:00:00 GMT

An experimental investigation on the relation of the heat-of-solution of dissociated substances to the effect of temperature on their solubility and dissociation Sammet, G. Victor. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1901; Includes bibliographical references (leaves 1-3).

The production, precipitation, and migration of colloids

Thu, 01 Jan 1903 00:00:00 GMT

The production, precipitation, and migration of colloids Sammet, C. Frank (Charles Frank) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1903; Includes bibliographical references (leaves 1-5).

Flexible discussion under student control in the ELIZA computer program : Coordination of small discussion units illustrated in a tutorial discussion of the train paradox of special relativity

Sun, 01 Jan 1967 00:00:00 GMT

Flexible discussion under student control in the ELIZA computer program : Coordination of small discussion units illustrated in a tutorial discussion of the train paradox of special relativity Hayward, Paul Raymond. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1967; Bibliography: leaf 33.

A layered virtual memory manager.

Sat, 01 Jan 1977 00:00:00 GMT

A layered virtual memory manager. Mason, Andrew Halstead. Thesis: Elec. E., Massachusetts Institute of Technology, Department of Electrical Engineering, 1977; Bibliography : leaves 127-132.

The product design process : a graphic novel

Wed, 01 Jan 2003 00:00:00 GMT

The product design process : a graphic novel Wong, Alison, 1981- Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2003; Includes bibliographical references (leaf 44).

Longshore labor conditions in the port of Boston

Fri, 01 Jan 1932 00:00:00 GMT

Longshore labor conditions in the port of Boston Hiscock, Earle F. Thesis: B.S., Massachusetts Institute of Technology, Department of Naval Architecture and Marine Engineering, 1932; Includes bibliographical references (leaf [190]).

A study of the practicability of enlarging the Lynn water supply with water from the Ipswich River

Fri, 01 Jan 1909 00:00:00 GMT

A study of the practicability of enlarging the Lynn water supply with water from the Ipswich River Madenigian, K.; Lenox, John E. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1909

Design of a four track railroad bridge over the Bronx River Parkway at Woodlawn N. Y.

Sun, 01 Jan 1933 00:00:00 GMT

Design of a four track railroad bridge over the Bronx River Parkway at Woodlawn N. Y. Morosoff, S. M. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1933

A study of the Boston longshoremen

Fri, 01 Jan 1954 00:00:00 GMT

A study of the Boston longshoremen Kariotis, Andrew S. (Andrew Stephen); Palmer, Valfrid E. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1954; Includes bibliographical references (leaves 99-100).

Frictional characteristics of quartz.

Sat, 01 Jan 1966 00:00:00 GMT

Frictional characteristics of quartz. Dickey, Joseph W., 1944- Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1966; Bibliography: leaf 70.

Design and construction of a band to position and set electromyographic surface electrodes for use on the upper leg

Sat, 01 Jan 1977 00:00:00 GMT

Design and construction of a band to position and set electromyographic surface electrodes for use on the upper leg Masters, Gene Paul. Thesis: B.S., Massachusetts Institute of Technology, Department of Biology, 1977

Recent developments in market research in New England industries

Wed, 01 Jan 1930 00:00:00 GMT

Recent developments in market research in New England industries Verveer, Louis. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1930; Includes bibliographical references (leaf 40).

An electronic accelerometer

Sun, 01 Jan 1939 00:00:00 GMT

An electronic accelerometer Mueller, Richard A. Thesis: B.S., Massachusetts Institute of Technology, Department of General Engineering, 1939; Includes bibliographical references (leaves 48-50).

The consolidation analogy model

Mon, 01 Jan 1951 00:00:00 GMT

The consolidation analogy model Rigas, Augustas C. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil and Sanitary Engineering, 1951; Bibliography: leaf 47.

A conservatory or school of music and of elecution

Fri, 01 Jan 1904 00:00:00 GMT

A conservatory or school of music and of elecution Codd, Eliza. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1904

Emission-tailored GaAsSb:Si luminescent diodes.

Wed, 01 Jan 1975 00:00:00 GMT

Emission-tailored GaAsSb:Si luminescent diodes. Brierley, Steven Kenneth. Thesis: Elec. E., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1975; Includes bibliographical references.

The Lawrence Water Works

Mon, 01 Jan 1877 00:00:00 GMT

The Lawrence Water Works Mudge, B. C. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1877

A roadway bridge across the Merrimack River between Groveland and Haverhill

Mon, 01 Jan 1877 00:00:00 GMT

A roadway bridge across the Merrimack River between Groveland and Haverhill Kittredge, Geo. W. (George Watson), 1856- Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1877

The Pawtucket Bridge at Lowell, Mass.

Mon, 01 Jan 1877 00:00:00 GMT

The Pawtucket Bridge at Lowell, Mass. Hale, Richard A. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1877

The Charles River Bridge

Mon, 01 Jan 1877 00:00:00 GMT

The Charles River Bridge Grover, E. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1877

The sea walls of South Boston flats

Mon, 01 Jan 1877 00:00:00 GMT

The sea walls of South Boston flats Gay, Martin, 1950- Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1877

The Lowell Water Works

Mon, 01 Jan 1877 00:00:00 GMT

The Lowell Water Works Gray, Joseph P. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1877

Central Avenue Bridge over the Neponset River, Dorchester, Mass.

Mon, 01 Jan 1877 00:00:00 GMT

Central Avenue Bridge over the Neponset River, Dorchester, Mass. Carter, Henry H. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1877

The highway bridge at Haverhill, Mass.

Sat, 01 Jan 1876 00:00:00 GMT

The highway bridge at Haverhill, Mass. Wood, Henry B. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1876

A trip to Nova Scotia

Tue, 01 Jan 1884 00:00:00 GMT

A trip to Nova Scotia Rich, W. J. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1884

A study of wing flutter

Sat, 01 Jan 1927 00:00:00 GMT

A study of wing flutter MeVay, Francis.; Rauscher, Manfred. Thesis: B.S., Massachusetts Institute of Technology, Department of Mathematics, 1927

A study of the flotation characteristics of cobaltite

Wed, 01 Jan 1958 00:00:00 GMT

A study of the flotation characteristics of cobaltite Decker, Thomas Garland. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1958; Includes bibliographical references (leaf 22).

Fusion zone properties of arc-welded modified 4330 steel

Wed, 01 Jan 1958 00:00:00 GMT

Fusion zone properties of arc-welded modified 4330 steel D'Andrea, Mark Michael. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1958; Includes bibliographical references (leaf 32).

Information processing in the MIT Admissions Office

Wed, 01 Jan 1975 00:00:00 GMT

Information processing in the MIT Admissions Office Breen, Daniel Edward. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1975; Bibliography: leaf [66].

Eastern Avenue Swing Bridge over Fort Point Channel, city of Boston

Sat, 01 Jan 1876 00:00:00 GMT

Eastern Avenue Swing Bridge over Fort Point Channel, city of Boston Waitt, Henry M. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1876

Headline specifications determination for computer-aided newspaper layout.

Wed, 01 Jan 1975 00:00:00 GMT

Headline specifications determination for computer-aided newspaper layout. Bracken, Diane Fay. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1975; MICROFICHE COPY AVAILABLE IN ARCHIVES.; Includes bibliographical references.

The correspondence of dislocation etch pits revealed on (111) and (100) surfaces of germanium grown in the <100> direction.

Wed, 01 Jan 1975 00:00:00 GMT

The correspondence of dislocation etch pits revealed on (111) and (100) surfaces of germanium grown in the <100> direction. Boylan, John Francis. Thesis: B.S., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 1975; Includes bibliographical references.

The cultural life of suicide : observing care and death at MIT

Mon, 01 Jan 2018 00:00:00 GMT

The cultural life of suicide : observing care and death at MIT Ko, Allan, S.B. Massachusetts Institute of Technology. Four undergraduate students died by suicide during my enrollment at MIT between 2013 and 2017. I document the ways in which suicide becomes more than the event of death itself, embedding itself back into everyday life. Suicide becomes what I describe as ambient and infrastructural, articulated through community traditions, announcement emails, Facebook posts, publicity posters, awareness flags, and all the other structures and artifacts of daily life in the MIT community. Drawing on field observations with the student-run texting help line Lean On Me, as well as interviews of students and administrators working in campus mental health organizations, I then explore how mental health organizations approach their work within an environment where suicide is ambient and infrastructural. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B. in Comparative Media Studies, Massachusetts Institute of Technology, Department of Comparative Media Studies/Writing, 2018; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 56-61).

Multimodal Learning Methods for the Fundamentals of Atomic Force Microscopy

Tue, 01 Jun 2021 00:00:00 GMT

Multimodal Learning Methods for the Fundamentals of Atomic Force Microscopy Ovitigala, Nisal Nanotechnology is a specialized field which requires an in-depth understanding of unintuitive concepts and significant capital for equipment. These requirements pose a large barrier to entry for the field and can intimidate students from pursuing studies in nanotechnology. This study explores the feasibility of teaching nanotechnology concepts, specifically the working principle of an Atomic Force Microscope (AFM), through multimodal learning methods to assess whether students have an easier time understanding unintuitive concepts. This study used a custom lowcost haptic feedback controller as the main interaction tool for students to “feel” the forces that an AFM tip feels as it approaches the surface of a sample and an activity was developed to teach students the concept of the force-distance (FD) curve in the AFM using the haptic feedback controller. This activity was implemented in the MIT Micro/Nano Engineering Laboratory class (2.674) with 11 students taking part in this experimental study. These students were split into two groups, Group 1 (N=7) and Group 2 (N=4), where students in Group 1 received regular lab instruction and students in Group 2 received the haptic activity after which both groups were asked to complete an assessment. The two groups then had their roles reversed and were asked to complete another assessment so that all students received both type of instruction. Results of the first assessment reveal that Group 1 students scored an average of 55% and Group 2 students scored an average of 88% showing that the haptic module taught students the FD curve more effectively. These results suggest that multimodal learning methods can be a useful tool in teaching students’ nanotechnology and hence, increases accessibility and lowers cost of teaching nanotechnology.

Design of Motor Controller for Intragastric Applications

Tue, 01 Jun 2021 00:00:00 GMT

Design of Motor Controller for Intragastric Applications Maier, Kai P. Intragastric devices are a tool which have the capability to help a great number of people around the world. However, as seen with the gastric balloon, intragastric devices also represent a danger to patients if they are designed poorly and are not studied in a variety of situations. Especially in the US there is a growing need for new and improved medical devices which can help study and treat gastric disorders such as obesity, Celiacs Disease, and Gastroesophageal Reflux Disease. This thesis showcases the design and possible utility of an intragastric motor controller which has the capability to remain within the stomach for long periods of time performing simple tasks or acting as a long term stomach health monitor. This device was designed using a custom PCB which would be powered by a Li-ion battery and would be able to maneuver a linear actuator actuated by a stepper motor. This device would then be placed through a simple example experiment to show its utility and feasibility

Implementing Climate Policy and Renewable Energy Technology – The Role of Lobbying

Tue, 01 Jun 2021 00:00:00 GMT

Implementing Climate Policy and Renewable Energy Technology – The Role of Lobbying Guettler, Darya C. Climate Change has become an increasingly discussed issue in the United States and around the world. Despite levels of support of over 60% in all states, very little action has been taken on this front in the United States. Understanding how to effectively implement renewable energy technology and climate policy will be vital for moving climate legislation forwards in coming years. This thesis analyzes the role that fossil fuel companies play in lobbying on climate legislation, and uses theoretical models of lobbying to categorize the behavior of the companies. Overall, lobbying was found to be skewed heavily towards the poles of climate opinion, namely those heavily in favor and heavily against climate policy legislation. It is found that lobbying expenditures from the largest oil and gas companies in the United States were related to the voting behavior of members of Congress from 2012-2020. Voting consistently against climate legislation was found to be a strong indicator for being lobbied by oil and gas companies. Members of Congress with anti-climate voting behavior were over two times as likely to experience lobbying. K-means clustering and PCA analyses also confirmed this, showing lobbying to be one of the largest predictors for categorizing behavior in Congress.

Strength, stretch, and cracking of Persian lambskin

Sun, 01 Jan 1950 00:00:00 GMT

Strength, stretch, and cracking of Persian lambskin Vort, Alan Harvey. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1950; Bibliography: leaf 58.

Television apparatus

Wed, 01 Jan 1930 00:00:00 GMT

Television apparatus Centeno V., Melchor. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1930; Includes bibliographical references (leaf 66).

Bubble migration in a velocity field

Tue, 01 Jan 1963 00:00:00 GMT

Bubble migration in a velocity field Lee, Man-Suk. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1963; Includes bibliographical references (leaf 31).

The effect of reducibility, time, load, and reducing gases on the hot strength of iron-ore pellets

Wed, 01 Jan 1958 00:00:00 GMT

The effect of reducibility, time, load, and reducing gases on the hot strength of iron-ore pellets Grimes, Donald Eugene. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1958; Includes bibliographical references (leaf 24).

Diffusivity of tin in low concentrations in silver

Wed, 01 Jan 1958 00:00:00 GMT

Diffusivity of tin in low concentrations in silver Carlson, Toby Nahum. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1958; Includes bibliographical references (leaf 17).

A theoretical investigation of liquid droplet evaporation in a high velocity gas stream

Mon, 01 Jan 1951 00:00:00 GMT

A theoretical investigation of liquid droplet evaporation in a high velocity gas stream Rivas, Miguel A. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1951; Bibliography: leaves 41-42.

A study of consumer acceptance of the Midget Louver in metropolitan Boston

Thu, 01 Jan 1948 00:00:00 GMT

A study of consumer acceptance of the Midget Louver in metropolitan Boston Foster, Robert E. (Robert Eugene); Mahfood, Winston.; Miller, Francis J. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1948

A study of feasibility of draining and irrigating a tract of land, in Westboro, Mass.

Thu, 01 Jan 1920 00:00:00 GMT

A study of feasibility of draining and irrigating a tract of land, in Westboro, Mass. Sehagian, E. K.; Shlager, A. E. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1920

Digital Communities x Collaborative Storytelling

Tue, 01 Jun 2021 00:00:00 GMT

Digital Communities x Collaborative Storytelling Liu, Clare All virtual spaces are driven by the people who reside within them, from the way the architecture is constructed and rearranged to the way people choose to inhabit and utilize these spaces. Although the methods of communication, the concept of identity, and the persistence of these digital spaces differ from their physical counterparts, how they should be designed and inhabited remains an inevitable question. In this thesis, I perform an ethnographic inquiry into a virtual roleplay community situated on the text and voice-chat program, Discord. My goal with this research was to provide insight into a niche corner of Internet communities, understand the affordances of the program and how they were utilized, and finally understand how these implements allowed the community to develop their own culture and succeed. By engaging with member activities within the virtual community, I documented my insights within the following scaffold: the members, their creations, the Discord platform, and the member-arranged server architecture. In my analysis, I sought to understand the relationships that emerged between the constraints of the platform, how users utilized these constraints, and how they interacted with one another, eventually proposing this virtual community’s process as one way to design a digital space for a creative community.

Consequence-Based Methodology to Determine Physical Security Requirements for Micro-Reactors

Tue, 01 Jun 2021 00:00:00 GMT

Consequence-Based Methodology to Determine Physical Security Requirements for Micro-Reactors Galanek, Leanne Micro-reactors are an emerging advanced fission technology seeking to provide clean energy solutions to aid in the global de-carbonization of energy systems. Without changes to current NRC regulations, micro-reactors may face unduly burdensome onsite physical security costs, leading to reduced economic attractiveness of the technology. A consequence-based methodology is developed and applied to two micro-reactor plants- the Oklo Aurora and the MIT Research Reactor- to better understand if the worst-case consequences of security breaches at micro-reactors warrant the need for onsite physical protection systems. Preliminary results indicate that micro-reactors may be able to prove that, based on inherent plant mitigation features alone, there are no unacceptable radiological consequences associated with any form of security attack on the plant. This would indicate that onsite physical security, including onsite armed guards, may not be necessary for micro-reactors to ensure the protection of the environment and public health and safety.

Early-Stage Research and Design of a Diagnostic Sensor for Peripheral Vascular Disease

Tue, 01 Jun 2021 00:00:00 GMT

Early-Stage Research and Design of a Diagnostic Sensor for Peripheral Vascular Disease Mahaffey, Hannah K. Peripheral Vascular Disease (PVD) is a blood circulation disorder that involves the narrowing and blocking of arteries in the lower extremities of the body. Symptoms of PVD include pain and restricted mobility, and as the disease progresses, it can lead to high risk of heart attack and stroke. PVD is underdiagnosed due the high amount of asymptomatic cases as well as issues with the current diagnosis process. The current process relies heavily on. The Ankle-Brachial Index (ABI). While ABI is an effective test, it is not widely preformed because it is time consuming and requires technical expertise. This project seeks to evaluate the possibility of developing a new diagnostic sensor or device to fill a similar role as ABI in the PVD diagnosis process. For evaluating the design space in the PVD diagnosis process, this project established clinical need for a new device, evaluates prior art, and then explores potential solutions. One potential solution identified is a modified digital ABI device that uses cuffless blood pressure measurements. Additionally, pulse oximetry is identified as a possible solution that would provide the fastest test time and greatest ease of use. Given the research done in this project, the recommendation for continuation is to pursue both potential solutions, but with an emphasis on expanding research into a pulse oximetry based device. If pulse oximetry is validated as a PVD screening method with similar accuracy to ABI, then it has the potential to be a fast and effective tool that will expand PVD screening in both primary care and hospital settings.

Fabrication Methods for Polarized Light Collages

Tue, 01 Jun 2021 00:00:00 GMT

Fabrication Methods for Polarized Light Collages Huang, Laura In this thesis, we discuss the best methods of fabricating polarized art collages, inspired by the artwork of Austine Wood-Comarow that creates brightly colored images from cellophane, a colorless birefringent material, placed in between two polarizers. Her artwork appears alive as the colors morph between images seamlessly and invites viewers to interact with it to explore the many images hidden within. To recreate the same color and image shifting result with a more streamlined process, we created a visualization tool and tested various laser cutting settings and fabrication processes. The visualization tool takes in two vector image inputs and allows the user to play around with the color and image shifting by mimicking the rotation of the polarizers or birefringent material. The optimal fabrication process of incrementally layering cellophane sheets with water as a temporary adhesive produces quality polarized light mosaics that reliably demonstrate the image morphing behavior.

The Impact of Radiometric Calibration Error on Earth Observation-supported Decision Making

Tue, 01 Jun 2021 00:00:00 GMT

The Impact of Radiometric Calibration Error on Earth Observation-supported Decision Making Baber, Sheila Earth Observation through satellites enables decision makers to assess situations near real-time with unprecedented spatial coverage. The data-value added products from radiometric satellite images often use indices derived from the unique spectral properties of materials and are sensitive to the relative gains of the different bands of the satellite sensor. However, satellite sensors are susceptible to degradation from the space environment, leading to drift in band response. For well-calibrated satellites such as Landsat 8, these drifts are well characterized and can be corrected for during processing—however, for satellites lacking on-board calibration (such as CubeSats), these trends can be difficult to detect and require novel methods combining cross calibration with machine learning. Given that satellite data often undergoes several levels of processing prior to use, there is a need to quantify the relationship between calibration errors and the errors of the final data-valued added product. This study investigates two applications of Earth Observation data: crop classification and Harmful Algal Bloom detection, and quantifies the impact of induced radiometric error on the final data product.

Optimizing Ion-Shuttling Operations in Trapped-Ion Quantum Computers

Tue, 01 Jun 2021 00:00:00 GMT

Optimizing Ion-Shuttling Operations in Trapped-Ion Quantum Computers Qi, Luke Trapped ions are a promising candidate for quantum computation. As experiments with ions increase in size and complexity, a trap array-based architecture for an ion trap with many independent zones provides a path towards large-scale integration. A crucial element in the operation of a trap array is the ability to split, move and recombine chains of ions on diabatic timescales and without incurring excessive decoherence of information stored in ion qubits. In this thesis, I investigate whether ion transport and splitting can be realistically integrated in the future quantum processor and what the requirements are to achieve this. I discuss my end-to-end numerical simulation pipeline of the ion shuttling process. Using these simulation tools, I investigate the leading theories for ion transport and splitting, based on Shortcuts-to-Adiabaticity principles, and extend these methods into two central criteria for optimal ion shuttling. I present a novel method for optimizing the voltage controls to achieve optimal ion shuttling, that use accurate models of the digital-to-analog converters, amplifiers, and low-pass filters of our ion trapping system. I demonstrate fast and robust transport of 40Ca on our custom-designed surface electrode trap and share spectroscopy data taken during the first ever attempt at optimal splitting. I then outline the necessary steps to achieve fast splitting with less than 1 quanta of excitation. It is my hope that the theories, software, and experimental results presented in this thesis demonstrate the feasibility of optimal ion transport and splitting in state-of-the-art, scalabale surface traps and become a standard for future ion shuttling experiments.

Randomized Benchmarking Simulations of Quantum Gate Sequences with Z-gate Virtualization

Tue, 01 Jun 2021 00:00:00 GMT

Randomized Benchmarking Simulations of Quantum Gate Sequences with Z-gate Virtualization Baldwin, Matthew James The implementation of quantum algorithms relies on high fidelity quantum gate operations. Single and two-qubit gate errors lead to reductions in the average fidelity of quantum gate sequences. Using the Z-gate virtualization procedure, the average sequence fidelity of single-qubit gate sequences can be increased. In two-qubit gate sequences containing the iSWAP gate, the Z-gate virtualization procedure can in some cases result in reduced average sequence fidelities due to the presence of coherent errors from the implementation of the iSWAP gate. In this thesis, we study the effect of single and two-qubit gate errors on the Z-gate virtualization procedure in single and two-qubit gate sequences. We develop randomized benchmarking simulations in order to identify when the Z-gate virtualization procedure is effective at increasing the average sequence fidelity.

Uncovering the Structure of the Galactic Bulge Using Kinematic Data from the JASMINE Near-Infrared Astrometric Satellite

Tue, 01 Jun 2021 00:00:00 GMT

Uncovering the Structure of the Galactic Bulge Using Kinematic Data from the JASMINE Near-Infrared Astrometric Satellite Lertprasertpong, Jitrapon The Galactic Center (GC) is the region with the most extreme stellar densities, a strong gravitational field, and the most prolific star formation region in the Milky Way. Furthermore, the Milky Way is the only galaxy that we can resolve individual structure such as Nuclear Stellar Disk (NSD) and Nuclear Bulge (NB) from the whole bulge structure. These reasons make the observation of the Galactic Center appealing to astronomers. Due to the high extinction from interstellar dust in the visible band (Aᵥ ≈ 30 mag), it is necessary to study the Galactic Bulge in the Near-Infrared (NIR) band. JASMINE mission is designed to observe the Galactic Nuclear Bulge at the region of 100-300 parsecs from the Galactic Center in the Near-Infrared band. In this thesis, we evaluate the capability of the JASMINE satellite in studying the galactic bulge structure in several aspects, including the JASMINE’s capability to distinguish gravitational potential models at the Galactic Bulge, possible uncertainties in JASMINE parallax and proper motion measurements, and the population of stars that JASMINE can observe. The result of this study indicates that JASMINE can distinguish two limiting cases of mass distribution: point mass, and homogeneous sphere within the proper motion accuracy in the order of 10 mas/year. In addition, we also notice that the accuracy of 25 µas for parallax measurement would result in the probability of 45% to mistake bulge star as disk stars. Finally, we also conclude that the sample population of stars suitable for JASMINE are Giants with a sample size of approximately 2.6 x 10⁵ stars.

The Implementation of Stellar Occultation Light Curve Modelling for Arbitrary Planetary Atmospheric Structures and the Analysis of Pluto’s Occultation Light Curves and Its Atmosphere

Tue, 01 Jun 2021 00:00:00 GMT

The Implementation of Stellar Occultation Light Curve Modelling for Arbitrary Planetary Atmospheric Structures and the Analysis of Pluto’s Occultation Light Curves and Its Atmosphere Tubthong, Chanita For decades, the analyses of stellar occultation light curves have been the most efficient method to study atmosphere of small solar system bodies. The variation in stellar flux due to the refraction in planetary atmosphere is directly related to the temperature profile of the planetary atmosphere. In this thesis, we implemented the occultation model derived by Chamberlain and Elliot (1997) [2], which is compatible with any occulting body with arbitrary temperature profile. The implementation was used to analysed Pluto occultation light curve of the star P384.2 on June 12, 2006. The result from the fit suggested that, if Pluto’s temperature profile in June 2006 were isothermal, it profile would be consistent with the surface temperature of 74.2 ± 1.4 𝐾. The best fit light curve from the isothermal model, however, expressed some inconsistency near the closest approach. The result, therefore, suggested that neither isothermal model nor the model with temperature gradient are sufficient to describe Pluto’s temperature profile. More complicated temperature profiles should be considered, which are enable with this implementation.

The Influence of Variable Oxygen Fugacity on the Source Depths for Lunar High-Titanium Ultramafic Glasses

Tue, 01 Jun 2021 00:00:00 GMT

The Influence of Variable Oxygen Fugacity on the Source Depths for Lunar High-Titanium Ultramafic Glasses Guenther, Megan E. High pressure, high temperature experiments were carried out under variable oxygen fugacity conditions on lunar high titanium ultramafic glasses to determine the conditions of multiple saturation where both olivine and orthopyroxene are stable on the liquidus. The investigated compositions are the Apollo 17 Orange glass (A17O, 9.1 wt.% TiO₂), Apollo 15 Red glass (A15R, 13.8 wt.% TiO₂), and Apollo 14 Black glass (A14B, 16.4 wt.% TiO₂). Experimental temperatures and pressures varied from 1420-1590°C and 1.4 to 4.0 GPa. Graphite and iron metal capsules were used to control oxygen fugacity (𝑓ₒ₂) at 1.5 log units above the iron-wustite (IW) buffer and 2.1 log units below IW, respectively. Our results indicate that the olivine - orthopyroxene multiple saturation point (MSP) shifts to higher pressures in the Fe metal capsules for each glass, and the magnitude of the shift (ΔMSP) increases with increasing TiO₂ content, an effect previously noted in Krawczynski and Grove (2012). We propose that TiO₂ content does indeed play the most significant role in causing this shift due to the reduction of Ti⁴⁺ in an ilmenite melt component to Ti³⁺ in a titanium-enriched armalcolite melt component. Our results confirm the occurrence of a late-stage overturn of the lunar magma ocean, and we suggest that the source region of the high-titanium ultramafic magmas is more oxidizing than previously assumed. More oxidized source region conditions are necessary for these magmas to be buoyant relative to their surrounding lunar mantle.

Phase-Coherent Drag of Plasmons in a 2D Flowing Fermi Liquid

Tue, 01 Jun 2021 00:00:00 GMT

Phase-Coherent Drag of Plasmons in a 2D Flowing Fermi Liquid Gao, Haoyang Collective modes in electron fluids feature phase-coherent drag response under a background carrier flow, resembling the optical Fizeau drag of photons by a moving medium. Time reversal breaking due to Fermi surface polarization by the flow results in nonreciprocity: collective modes acquire a ±𝑘 asymmetry in mode dispersion. This thesis explores plasmonic drag in two-dimensional electron fluids with a full account given to the Fermi-liquid interactions. These interactions are essential when the electron band is nonparabolic, as in graphene, giving rise to subtle “motional” Fermi-liquid effects which describe the flow-induced change in the quasiparticle velocities and interactions. These new Fermi-liquid effects can be represented as the flow-dependent interactions between quasiparticles on the Fermi surface deformed by the flow, in general not reducible to the standard Fermi-liquid parameters. A model of graphene Fermi-liquid predicts a substantial enhancement in the plasmon frequency shift, pointing to an opportunity to directly probe the motional Fermi-liquid effects in plasmonic near-field imaging experiments.

Implementing Continuous Fiber Reinforcement for Concrete Additive Manufacturing

Tue, 01 Jun 2021 00:00:00 GMT

Implementing Continuous Fiber Reinforcement for Concrete Additive Manufacturing Nelson-Arzuaga, Chloe Concrete additive manufacturing is a promising alternative to standard concrete construction, but the inability to print reinforcement as part of the manufacturing process is a significant limitation. This thesis proposes a method of extruding continuous fiber reinforcement during the 3D printing process. Reinforcement is important in the process of creating concrete structures because while concrete is strong in compression, it has almost no tensile capacity. Reinforcement compensates for this by introducing a high-tensile strength material such as steel rod into the concrete to give it tensile properties. Current methods of reinforcing concrete 3D printing mainly consists of manually adding rebar into cavities created during the printing process (Mechtcherine et al., 2018). Since the rebar has to be cast into place by hand, many of the benefits of having an autonomous process are reduced. This project designed an extruder for a continuous strand of Kevlar to be extruded alongside the concrete extrusion. Through controlling the speed at which the Kevlar extruder was linearly translated, different densities of Kevlar were created within two layers of concrete. These reinforced concrete pieces were then tested against a similar, but unreinforced piece. The results of this test showed an increase in the residual strength of the concrete as the density of Kevlar was increased. This proves the validity of Kevlar as a reinforcing material and could lead to a more flexible method of adding reinforcement to 3D printed concrete.

Mechanical Engineering Student Perspectives on the Impact of Company Sustainability on their Career Decisions

Tue, 01 Jun 2021 00:00:00 GMT

Mechanical Engineering Student Perspectives on the Impact of Company Sustainability on their Career Decisions Kennedy-Moore, Sheila Companies can be an important part of solving major world problems such as climate change, pollution, and race and gender-based inequalities. Although awareness of the need for corporate sustainability has grown, companies could be doing a lot more. During the recruiting process, students showing they care about corporate sustainability can pressure companies to do more. As the number of students who are asking companies sustainability-related questions or showing they value corporate sustainability increases, it becomes more likely that companies will feel pressured to change to attract new talent. To empower more students to pressure companies this thesis aims to understand how MIT mechanical engineering seniors currently consider sustainability with respect to their career decisions and what would make students more likely to think of sustainability as an important aspect of their career decisions. The analysis found that although the majority of students care about sustainability, they face barriers such as knowledge gaps, lack of preparation, and discomfort. These barriers prevent them from questioning companies and factoring sustainability into their career decisions. Educating students on corporate sustainability, how to evaluate, and question companies may help reduce these barriers. Additionally, students may feel more empowered if they understand the impact they can have on corporate sustainability.

NUSTAR and XMM-Newton Spectroscopy of Ark 564

Tue, 01 Jun 2021 00:00:00 GMT

NUSTAR and XMM-Newton Spectroscopy of Ark 564 Zhang, Rachel C. Ark 564 is a Narrow line Seyfert 1 that has been well observed in the 0.3-10 keV X-ray band. It has also been previously observed in the 3-50 keV band in a previous analysis using 200 ks NuSTAR observational data [24], which has revealed features such as a steep spectrum, strong soft excess, an iron K emission line, and dramatic variability. We conduct a detailed analysis combining this 2015 NuSTAR observation with another 2 NuSTAR observations, one for 400 ks, and a shorter one for 38 ks, both collected in 2018. We also include 2 ~114 ks XMM-Newton observations that overlap with the 400 ks NuSTAR observation to span the whole 0.3-50 keV energy range. We perform spectral analysis of both the NuSTAR and the NuSTAR+XMM- Newton data to test whether previously observed features are still displayed. We find that the best fit model requires a relativistic reflection component, although the current state of available models still needs to be improved on to understand the physical picture of these sources. We also examine the root mean square (RMS) spectra of the observations and find that the current models underestimate the variability of the soft excess, which could imply a higher variable reflection component or an additional variable soft excess component.

Tunable Three-Dimensional Photonic Crystal Microwave Resonator with Ultra-Small Mode Volume

Tue, 01 Jun 2021 00:00:00 GMT

Tunable Three-Dimensional Photonic Crystal Microwave Resonator with Ultra-Small Mode Volume Chotrattanapituk, Abhijatmedhi Microwave resonator is an important electromagnetic tool with applications in many areas, including communication, nonlinear optics, cavity quantum electrodynamics, and precision metrology. In this work, we did simulations and experiments on a design of three-dimensional (3D) dielectric photonic crystal (PhC) cavity (PhCC) based on ABCD woodpile structure. Low material loss of the dielectric and radiation loss suppression of the 3D PhC’s complete bandgap give PhCC high quality factor (𝑄). The design also includes field focusing structure into the PhCC to achieve ultrasmall effective mode volume (𝑉ₑ subscript 𝑓𝑓). Moreover, the topology of the woodpile structure allows us to tune the PhCC’s resonance frequency as well. Our simulation results agree with the experiments’ on the band structure of the PhC, 𝑄, and the tunability of the PhCC. Furthermore, the simulation shows that we can achieve indefinitely small 𝑉ₑ subscript 𝑓𝑓 by the field focusing structure limited only by the fabrication resolution. Our experiments on the design’s 6 × 6 × 5 unit-cell PhCC demos give a complete bandgap between 3.6 GHz and 4.1 GHz. We measured their 𝑄 to be in the order of 10² for the resonance inside the complete bandgap regardless of the existence of the field focusing structure which normally cause high radiation loss. We also can tune the resonance of the PhCC up to 64% of the width of the complete bandgap.

Benchmarking of neutrino energy reconstruction methods using electron-deuterium scattering data

Tue, 01 Jun 2021 00:00:00 GMT

Benchmarking of neutrino energy reconstruction methods using electron-deuterium scattering data Nambrath, Anjali Neutrinos exist in one of three types or “flavors” (𝜈ₑ , 𝜈 subscript 𝜇, or 𝜈 subscript 𝜏 ) which oscillate from one to another when propagating through space. Understanding the detailed features of this phenomenon can provide new insight into the nature of our universe. Neutrinos oscillate as a function of their propagation distance divided by their energy (𝐿/𝐸), so experiments extract oscillation parameters by measuring the neutrino energy distribution at different locations. As accelerator-based oscillation experiments cannot directly measure 𝐸, their interpretation relies heavily on phenomenological models of neutrino-nucleus interactions to infer 𝐸. Here, we exploit the similarity of electron- and neutrino-nucleus interactions, and use electron-scattering data with known beam energies to test energy reconstruction methods and interaction models. In particular, we analyze 5 GeV electron-deuteron scattering data measured using the large-acceptance CLAS detector at Jefferson Lab. Despite deuterium having a simple nucleus that is relatively well-understood, we find that large nuclear effects can bias the electron beam-energy reconstruction. We thus develop a set of event selection cuts that strongly suppress nuclear effects and propose a viable path for precision measurements. We further compare our data with the theoretical predictions of the GENIE event generator, commonly used by most neutrino experiments based in the US, to validate simulation models used for interpreting lepton-nucleus scattering reactions.

No Winning Moves: Calculated Casualties and Damages of a Nuclear Attack on the United States by Russia for First and Second Strike Scenarios

Tue, 01 Jun 2021 00:00:00 GMT

No Winning Moves: Calculated Casualties and Damages of a Nuclear Attack on the United States by Russia for First and Second Strike Scenarios Montoya, Natalie G. Simulations of nuclear attacks are a valuable assessment tool to analyze the capabilities of arsenals in order to inform policies and negotiations. Targeting strategies were developed for Russian first strike, Russian second strike with strategic warning, and Russian second strike without strategic warning scenarios utilizing the full Russian arsenal for the first strike and only the arsenal expected to survive a U.S. first strike with and without warning for the second strikes. The countervalue targets consisted of oil refineries and pipelines, shipping ports, and high voltage (HV) transformers in order to eliminate the U.S. supply of petroleum products and blackout the electrical grid. Beyond infrastructure damage, the blast fatalities and injuries were calculated using NUKEMAP, and the number of U.S. missile silos expected to survive an attack was calculated using a Monte Carlo simulation. The Russian first strike resulted in 49.73 million casualties and all oil refineries and major shipping ports and 2,809 HV transformers destroyed with 132—-225 surviving U.S. silos and 520 unused warheads. The Russian second strike with strategic warning resulted in 69.86 million casualties; all oil refineries, all major shipping ports, and 2,244 HV transformers destroyed with 783 or more unused warheads. The second strike without strategic warning resulted in 7.76 million casualties and 71 oil refineries, 27 major shipping ports, and 618 HV transformers destroyed. This study showed that deep arsenal reductions are possible while maintaining deterrence, the role of the U.S. ICBMs should be evaluated, and grid security and oil dependence should be addressed.

Constructing a High-Resolution Record of Silurian Paleoclimate Using Carbonate Oxygen Isotopes

Tue, 01 Jun 2021 00:00:00 GMT

Constructing a High-Resolution Record of Silurian Paleoclimate Using Carbonate Oxygen Isotopes Clarke, Julia W. The collection of δ¹⁸O data from carbonates provides insight into the temperature of Earth millions of years ago. Paleozoic δ¹⁸O records are currently compiled from brachiopod fossils because of their resistance to diagenetic alteration, but this data is relatively sparse and not well time-resolved. Bulk carbonate δ¹⁸O data can present a more full view geographically and temporally, but is more susceptible to diagenesis. Here we overcome these challenges by using simple age models alongside previously collected δ¹⁸O data from δ¹³C studies to show that bulk carbonates can preserve a primary isotopic signal of Silurian temperatures, as well as generate a high-resolution climate record of the Silurian Period that correlates climate fluctuations with δ¹³C events. We then present Δ47-derived temperatures from clumped stable isotope analysis from four Silurian sites, and show that the reported temperatures can be consistent with the bulk rock δ¹⁸O record. With bulk carbonate δ¹⁸O measurements able to reconstruct an accurate record of Silurian temperatures, this generates an even larger dataset than the existing brachiopod compilation from E. Grossman and Joachimski (2020), and shows that this technique can be further applied to construct temperature records throughout the Paleozoic. Additionally, having a clear link between δ¹³C and temperature allows for a better understanding of carbon isotope excursions and their causes.

Electromagnetic and Systems Design of a Permanent Magnet Synchronous Motor for an Electric Vehicle

Tue, 01 Jun 2021 00:00:00 GMT

Electromagnetic and Systems Design of a Permanent Magnet Synchronous Motor for an Electric Vehicle McCabe, Rebecca G. This project explores the analysis and design of a Surface Permanent Magnet (SPM) motor for an electric racecar application. Magnetic fields and forces are analyzed using simplified magnetic circuits as well as the more accurate magnetic scalar potential and the Maxwell stress tensor. Thermal analysis is performed to determine peak and continuous current capability. Parameter sweeps are used to optimize machine design for a 20 kW hub motor in a student-built high-performance electric vehicle. The optimization maximizes simulated points scored in the Formula Society of Automotive Engineers (FSAE) competition. Performance is estimated with full-vehicle sensitivities linearized around the point of breaking traction.

Vehicle Dynamics on an Electric Formula SAE Racecar

Tue, 01 Jun 2021 00:00:00 GMT

Vehicle Dynamics on an Electric Formula SAE Racecar Gaither, Audrey Vehicle dynamics on a Formula SAE vehicle are inter-dependent with almost all mechanical systems on the car and require a thorough understanding of design tradeoffs in order to maximize the vehicle’s acceleration capabilities while maintaining consistent driver feedback. This thesis summarizes the developments and accumulated knowledge on MIT’s Formula SAE team with regards to suspension and vehicle dynamics of the 2018 – 2020 seasons in order to inform the design and vehicle development for future years. Vehicle kinematics, vehicle dynamics, and tire selection are covered, in addition to the impact of aerodynamics, steering, and control arms on suspension development. Areas for further research are described. Throughout the thesis, the importance of quantifying and documenting design decisions is highlighted.

Characterization of Magic-angle Twisted Bilayer Graphene using Microwave Techniques

Tue, 01 Jun 2021 00:00:00 GMT

Characterization of Magic-angle Twisted Bilayer Graphene using Microwave Techniques Dinh, Thao H. Magic-angle twisted bilayer graphene (MATBG) is a highly tunable material platform that exhibits a wide range of novel phases, including correlated insulating states and unconventional superconductivity. Its tunability and potentially high kinetic inductance in the superconducting state are desirable properties for high-coherence, small-form-factor superconducting qubits. This thesis presents a promising experimental method to characterize MATBG in the gigahertz-frequency regime, the operating regime of superconducting qubits. A hybrid on-chip DC-microwave circuit, which integrates a DC four-probe measurement and microwave resonator readout functionalities, enables the investigation of DC transport response and microwave response in the same twisted bilayer graphene device. By measuring the frequency shift of a standard Aluminum coplanar waveguide resonator terminated by a twisted bilayer graphene device, we can extract the contribution of the twisted bilayer graphene inductance. We expect that the experimental method can be utilized to measure MATBG kinetic inductance and superfluid density in a non-invasive manner. This experiment will also be a crucial step towards realizing MATBG-based superconducting qubit circuits.

Design and Characterization of a Nonlinear Stiffening Spring for a Series-Elastic Ankle-Foot Prosthesis

Tue, 01 Jun 2021 00:00:00 GMT

Design and Characterization of a Nonlinear Stiffening Spring for a Series-Elastic Ankle-Foot Prosthesis Klein, Melissa A. Over 150,000 patients in the United States undergo a lower extremity amputation every year. Powered ankle-foot prostheses greatly improve amputees’ walking experiences by replicating the biological motion of human gait. Series elastic actuators improve the prostheses, simulating the function of a biological tendon by storing and releasing energy during gait, reducing the mechanical work required by the motor and transmission system. This thesis aims to describe the preliminary design and characterization of a nonlinear stiffening spring, which acts as the elastic element of a powered transtibial prosthesis with cycloidal drive transmission. A mathematical model for angular deflection of the spring wrapping around a cylindrical surface was created, and finite-element analyses were performed to analyze the impact of individual design parameters on the spring stiffness. An experimental setup was designed and built to measure the deflection angle of the spring as a vertical force is applied. Three springs made from nylon 6/6 were tested in this thesis at thicknesses of 26 mm, 27.5 mm, and 29 mm, which yielded a 931.4±3.7 Nm/rad, 1076±5 Nm/rad, and 1234±5 Nm/rad stiffness, respectively. This lays the groundwork for the development of a unidirectional carbon fiber foot spring whose high strength-to-weight ratio is able to achieve the target stiffness while minimizing weight.

Possibilities for DERs: Evaluating Existing and New Models for DER Participation

Tue, 01 Jun 2021 00:00:00 GMT

Possibilities for DERs: Evaluating Existing and New Models for DER Participation Shrestha, Swochchhanda A literature review was performed to evaluate existing participation models for distributed energy resources (DERs), including those of both the demand response variety and the distributed generation variety (such as small-scale solar rooftop solar PV). This literature review consisted of both academic papers and public information from commercial DER aggregators. Through the literature review, DER participation models in different regions of the United States were determined. In some areas, such as New England, DERs can only participate independently as price-takers in the wholesale electricity market while other regions, such as California, allow DERs to actively bid into the wholesale electricity market through large-scale aggregators that represent many individual DERs. Potential novel models for DER participation were also examined in the form of retail markets, which have been covered extensively in past work done by MIT’s Active Adaptive Control Lab. Under these proposed retail markets, a Distribution System Operator (DSO) coordinates energy transactions with local DERs while interfacing with the wholesale electricity market to maintain system reliability. Previous research on the topic of these novel retail markets suggests that they are well equipped for scheduling and responding to variations in DERs in real time. DER participation models of the California Independent System Operator (CAISO) and the Independent System Operator – New England (ISO-NE) were modeled onto a 30-bus network, and simulated using historical data of load demand from each Independent System Operator. The performance of these models in key metrics of average cost paid per node and the uptake of DERs were compared to the same systems under a retail market using the IEEE 123-bus network. The simulation results suggest that existing models of DER participation are not as effective as the proposed retail market in these key metrics.

Implementing a Lattice Formulation of the Schwinger Modelwith Periodic Boundary Conditions Using Tensor Networks

Tue, 01 Jun 2021 00:00:00 GMT

Implementing a Lattice Formulation of the Schwinger Modelwith Periodic Boundary Conditions Using Tensor Networks Kazi, Sujay I attempt to develop a simple tensor network formulation of the Schwinger model with periodic boundary conditions. The primary challenge is to enforce the local constraints imposed by Gauss's Law. I do this by combining global conservation of a specially defined quantum number with the local optimization steps used in the density matrix renormalization group (DMRG) algorithm for finding the ground state of a quantum system. However, due to practical constraints, I still use matrix product states and matrix product operators with open boundary conditions. I demonstrate the efficacy of the model in computing the bulk limit (the limit as the number of lattice sites goes to infinity) for the energy density, chiral condensate, and electric field energy density of the ground state. Future investigation should begin with recreating the model using periodic matrix product states and matrix product operators and using a version of DMRG that has been optimized for periodic boundary conditions.

Measuring the Reconstructed A' Acceptance of the Darkquest Electromagnetic Calorimeter

Tue, 01 Jun 2021 00:00:00 GMT

Measuring the Reconstructed A' Acceptance of the Darkquest Electromagnetic Calorimeter Cuadra, Sergio E. The Darkquest experiment seeks to utilize the existing proton dump beam and detector array at Fermilab, along with the addition of an Electromagnetic Calorimeter (EMCal), for a low cost but well suited way to search for dark matter candidates at energies in the MeV to GeV range. Darkquest will focus specficially on searching for long lived dark photons. We use simulation data to achieve three main goals as part of our preparation for the Darkquest project: Calibration of the EMCal, reconstruction of electron paths through the detectors, and most importantly, measuring the rate of geometric acceptance once the EMCal is added. We found that the reconstructed acceptance rates are in agreement with those predicted by theory for the bremsstrahlung emission production method, and slightly below predictions at low masses for the $\eta$ meson decay production method. These results support the idea that Darkquest will be able to effectively measure dark photon production at the proposed mass ranges.

Participatory Design in the Himalaya: Understanding Himalayan Home Cooking and Heating Practices

Tue, 01 Jun 2021 00:00:00 GMT

Participatory Design in the Himalaya: Understanding Himalayan Home Cooking and Heating Practices Patel, Arnav Y. Communities in the Himalaya continue to use biomass-fueled cooking and heating arrangements, which have the potential to introduce harmful levels of household air pollution (HAP) and use fuels inefficiently. Utilizing participatory design practices, fifteen surveys were conducted in three villages in the Chakrata district of Uttarakhand, India to assess household cooking and heating problems and needs. The scale of the survey implementation was in part limited due to the COVID-19 pandemic and its devastating impact on India during 2020 and 2021. The results of these surveys indicated a need for more efficient cooking and heating systems that emit less HAP. These households presented different needs than surveys of other regions of the Himalaya, underscoring the necessity of participatory design and co-creation at even the village level for possible cooking and heating solutions. Following this preliminary survey, next steps were created on clarifying answers from the community, gathering measurements of household cooking and heating methodologies, and evaluating priorities and potential solutions.

Digital Narratives for Self-Therapy

Tue, 01 Jun 2021 00:00:00 GMT

Digital Narratives for Self-Therapy Kwak, Seo Yeon Trauma exposure, whether caused by external events or internal struggles, is experienced by many individuals around the world, leaving them in need for emotional healing. This process has been studied by psychologists throughout many years, but today, it is something that should be pursued more strongly than ever before. With COVID-19, social isolation has become a norm and has illuminated the need for accessible and everyday methods of emotional growth and healing. Digital products are a promising solution to making self-therapy methods more accessible and flexible to individuals’ lifestyles. This thesis explores the application of digital narratives in encouraging emotional healing and self-therapy. Storytelling has been a significant means of growth and learning throughout all of human history and across all cultures. The potential for reading personal stories to become a popular means of emotional support has already been experienced, such as through the success of the “Chicken Soup for the Soul” book series. Turning personal, moving stories — such as those in the book series — into digital experiences opens the opportunity to enrich them with audio, visual, animated, and interactive elements. It also makes possible a scalable and flexible system for lightweight self-therapy that can be accessed by many people around the world, at any time or location that fits into each individual’s lifestyle. This thesis project is proposed as a case study that can be expanded in the future to create a robust system for self-therapy through digital storytelling.

Design of a Pressure Vessel to Characterize Frictional Ignition of Metals in High-Pressure Oxygen Environments

Tue, 01 Jun 2021 00:00:00 GMT

Design of a Pressure Vessel to Characterize Frictional Ignition of Metals in High-Pressure Oxygen Environments Allen, Kailey The components of rocket engines are exposed to environments that are oxygen-rich, reach high-pressures, and cause the abrasion of rotating parts. Studies have shown that these conditions cause nearly all metals to develop an oxide tribolayer, which initially lubricates the rubbing surface, but later exposes fresh metal to be ignited once it wears away [1]. Frictional ignition has caused multiple catastrophic vehicle failures, and the mechanisms that drive it are poorly understood [2, 3]. Understanding the factors behind wear and ignition of different metals in rocket engines is essential to making more informed design decisions that prevent failures. One way to characterize the behavior of metals is to perform experiments in a testing rig that simulates the conditions of rocket engines. The goal of this study is to create a pressure vessel for such a rig. After designing and analyzing two vessels, it was determined the final design will be cylindrical and allow the use of a torsional sonotrode to rapidly wear down samples, which will be imaged and measured to determine the relative flammability of different metals.

Developing a Platform for Expanding AUV exploRation to Longer ranges (PEARL)

Tue, 01 Jun 2021 00:00:00 GMT

Developing a Platform for Expanding AUV exploRation to Longer ranges (PEARL) Tran, Jimmy Autonomous underwater vehicles (AUVs) are often limited in their range and mission time due to their battery capacity. Additionally, the data onboard AUVs usually needs to be downloaded directly, due to their limited data transmission capabilities, requiring time and labor to fish the AUVs out of the water. The Platform for Expanding AUV exploRation to Longer ranges (PEARL) described in this thesis aims to extend the range and duration of AUVs while reducing the overall operating cost. PEARL is an autonomous floating platform that utilizes renewable energy to recharge docked AUVs, while simultaneously uploading their mission data to a high-bandwidth low-Earth orbit satellite constellation for remote access and monitoring. This thesis describes the various stages of design and testing to develop PEARL. The first prototype explores the structures and docking capabilities of PEARL to inform initial designs. A model was then created and validated to predict energy management onboard PEARL to determine the optimal power system to be implemented. A larger scale prototype was then created, integrating several systems like sensing, energy production and management, data transmission, and autonomous waypoint navigation. This prototype was then placed in an aquatic environment for six months to monitor its interaction with the environment during long-term testing. The results will be used to inform design changes for the full-scale prototype.

Cooling Power Electronic Building Blocks Aboard Navy Ships

Tue, 01 Jun 2021 00:00:00 GMT

Cooling Power Electronic Building Blocks Aboard Navy Ships Padilla, Joushua G. The Navy Integrated Power and Energy Corridor (NiPEC) is a modular entity that encapsulates all the power handling requirements of a shipboard power and energy distribution system including transmission, conversion, protection, isolation, control and storage. The basic component of the NiPEC is the Power Electronics Building Block (PEBB), which is envisioned to be a universal converter that is programmed for the specific application when installed. The PEBB is a modular unit that can be easily swapped out and is small and light enough to be carried and installed by a single person. One constraint placed on the PEBB to ensure ease of swapping is that no liquid can cross the boundary of the PEBB, thus eliminating the possibility of leaking at the interface. This thesis describes the design and analysis of a system for removing up to 10 kW of heat from each PEBB in a stack of four PEBB units, using liquid cooling via a dry interface. This is achieved by hard-mounting cold plates in the electronics cabinet, placing the heat-transfer surface of each PEBB adjacent to a cold plate, and improving heat transfer across the interface through the use of a thermal pad. The thesis presents initial thermal and structural analyses using analytical models, computational fluid dynamics and mechanical design tenets. These analyses demonstrate that this is a viable solution to the PEBB cooling problem.

Design and Manufacturing of a Novel Intraoral Prosthesis for Obstructive Sleep Apnea

Tue, 01 Jun 2021 00:00:00 GMT

Design and Manufacturing of a Novel Intraoral Prosthesis for Obstructive Sleep Apnea Maloney, Charlotte A. Obstructive sleep apnea (OSA) is a common chronic condition which requires ongoing, often lifelong, management. It is a global problem which, left untreated, can result in lower quality of life and general health. Although a wide range of existing treatments exist, their rates of compliance among patients are low. Along with our MIT Catalyst team, I set out to develop and refine a device which prioritized patient comfort with a minimally intrusive design while maintaining safety and efficacy in reducing OSA. I tested multiple parameters within the device to optimize comfort and created a comfort survey to evaluate success. Throughout this process, I simultaneously developed and documented my manufacturing technique for the device, providing a foundation for further tests in patients to measure OSA reduction. In combination with altering the design for comfort, I completed computational simulations in Abaqus to ensure the device did not damage intraoral tissue. This model will allow for team members to quickly test different device configurations prior to manufacturing. Further development of the computational model is necessary to fully mimic the biological tissue.

When Being Sick Makes Us Sicker: A Black Feminist Approach to Financial Toxicity

Tue, 01 Jun 2021 00:00:00 GMT

When Being Sick Makes Us Sicker: A Black Feminist Approach to Financial Toxicity Davis, Meghan E. Health and wellbeing have a significant impact on our quality of life. They matter to people. Unfortunately, there are vast inequities in healthcare and health outcomes in the United States on the basis of race, gender, and class. Often, being sick makes people sicker, especially those impacted by the aforementioned systems of oppression – racism, sexism, and class. One axis through which being sick makes us sicker is the financial toxicity of sickness. Here, financial toxicity is defined as the negative health effects of financial hardship, typically associated with health care. In this thesis we take a Black Feminist approach towards understanding the mechanism of financial toxicity using the Healthy Neighborhood Study, a participatory action research study in nine Massachusetts communities. We observe a significant relationship between health status, stress, and financial insecurity and propose next steps for Black Feminist research in the Health Neighborhood Study

Modeling of Nanostructured Heaters for Out-of-Oven Curing of Aerospace Composites

Tue, 01 Jun 2021 00:00:00 GMT

Modeling of Nanostructured Heaters for Out-of-Oven Curing of Aerospace Composites Jung, Minsu Primary aerospace composite structures have traditionally been processed by applying vacuum, heat, and pressure to a laminate using an autoclave. More recently, aerospace secondary structures have been able to be processed without the need of an autoclave, but with just vacuum pressure in an oven. However, both of these methods are energy, space, and time intensive processes. A new composite manufacturing approach has recently emerged that utilizes carbon nanotube (CNT) based heaters to conductively cure the composite (termed out-of-oven, OoO curing) and nanoporous network (NPN) materials to replace the need for autoclave pressure. The OoO curing method uses CNT films which act as a thin-film heater to conductively process a composite structure. OoO curing is enabled by the advantageous thermal and electrical properties of CNT networks, which allow Joule heating to be used by applying a voltage to the CNT films. This approach was previously found to reduce the energy to cure a composite by ∼ 2 orders of magnitude when compared to conventional oven-based techniques and presents much greater flexibility for complex structures and curing configurations. This thesis models the composite cure process driven by CNT film heaters with ANSYS Composite Cure Simulation (ACCS) and particularly focuses on a curing configuration of two heaters with a non-heated gap in the middle, needed for both scaling of the OoO approach and for spatial cure tailoring. It is found that a minimum gap of 5 mm between two CNT film heaters is recommended for a maximum difference of 12 ∘C and 2.3% degree of cure (DoC) between the centers of the heated and the non-heated zones as a worst case scenario. Experimental verification of the computational temperature results is performed to verify the simulation results.

Design of an Automated, High-Throughput Optical Characterization Tool for Photovoltaics

Tue, 01 Jun 2021 00:00:00 GMT

Design of an Automated, High-Throughput Optical Characterization Tool for Photovoltaics Troupe, Anthony Photovoltaic (PV) devices are traditionally optimized through an iterative, top-down engineering approach in which many devices are built, tested, and studied to determine where performance improvements can be made. Researchers typically perform multiple measurements on each device using various manual characterization tools. This practice is ultimately time-intensive, inefficient, and expensive. This thesis documents the development of an automated, large-format characterization tool capable of performing multiple optical measurements simultaneously in order to address existing PV characterization inefficiencies. The resulting prototype demonstrates potential to serve as a high-throughput research tool that could ultimately advance the pace of future PV research.

An Analysis on the Environmental Impact of the Fashion Industry

Tue, 01 Jun 2021 00:00:00 GMT

An Analysis on the Environmental Impact of the Fashion Industry Navarro, Alejandra M. The fashion industry is a large global sector. Cultivation, manufacturing, and distribution is spread out throughout the world with travel connecting all these pieces to deliver garments. With clothing accounting for 7% of the world’s exports, demand is high, and the sector is evidently growing. This projected growth, however, is not able to be sustained for much longer. This thesis explores the current state of the industry, expanding on different metrics to grasp its impact on the environment. The lifecycle of textiles is used to get a holistic picture of the fashion world. With pressure on companies and individuals to change and adopt to needed sustainability efforts, there are already movements occurring to encourage a green industry. These are seen through alternative textiles, new technologies, and sustainable marketing. Studies reveal that consumers’ shopping behaviors do not always agree with their belief that current environmental status is a concern, which could pose new threat. With promising solutions emerging, the time to act and mobilize action to reshape the fashion industry is now.

Investigation of Interstellar Object Flux Through the Solar System

Tue, 01 Jun 2021 00:00:00 GMT

Investigation of Interstellar Object Flux Through the Solar System Hahn, Katherine M. Currently, the number of interstellar objects through the solar system is a key factor in creating engineering projects that will allow for ISOs to be studied more closely, revealing important information about planetary formation and star system history. Thus, a current observational upper limit of the number density of ISOs through the Solar System was calculated. An updated number density was calculated by incorporating two known ISOs into Engelhardt’s previous estimates which were created through simulation of synthetic ISO detection through the Pan-STARRS1 telescope (Engelhardt 2014). The updated number density was estimated as 0.11 AU⁻³ and 3 * 10⁻³ AU⁻³ for an inert and active population of ISOs, respectively. As more ISOs are detected, it is estimated the number density will continue to increase following a Poisson Distribution until 15 ISOs have been detected at which point a new distribution should be invoked. The increased number density provides motivation for new scientific missions which will aim to explore complex topics such as planetary formation.

Incorporating Mullins Effect into the Modeling of Hyperelastic Actuators

Tue, 01 Jun 2021 00:00:00 GMT

Incorporating Mullins Effect into the Modeling of Hyperelastic Actuators Callahan, Andrew B. The use of hyperelastic materials in actuators has become increasingly popular due their immense number of degrees of freedom, ability to recover from large deformations, and the capability to absorb energy in many types of environments. Some prototypes for these actuators utilize instabilities that result from the nonlinear stress-strain response in these hyperelastic materials. However, these prototypes fail to include in their supporting analysis any sort of irreversible processes whose inclusion would help realize their potential in cyclical loading scenarios. One such irreversible framework is the Mullins effect, which describes a range of phenomena, most importantly stress softening, that all depend on the hysteresis in deformation of the material. This thesis proposes a comprehensive model that captures Mullins effect stress softening and its subsequent convergence. An experimental study was performed to calibrate a hyperelastic pressure-volume relationship for thin-walled cylinders with Ogden-Roxburgh damage. Included in this model is a fractional multiplier to capture the convergence of stress softening after roughly 10 cyclic loadings. The Ogden-Roxburgh model was calibrated using uniaxial tension tests on super-soft latex samples, and the fractional multiplier was calibrated via cyclic fluid loadings on separate samples. Ultimately, this model allows for a more precise understanding of how a hyperelastic actuator will respond over many load cycles.

Development and Analysis of a Minimally Invasive Post-Infarction Epicardial Patch Delivery Device

Tue, 01 Jun 2021 00:00:00 GMT

Development and Analysis of a Minimally Invasive Post-Infarction Epicardial Patch Delivery Device Tagoe, Jonathan(Jonathan N.) After a myocardial infarct (heart attack), the heart develops scar tissue that can impede normal function and eventually result in heart failure. There are a number of methods currently employed in the field to slow this degeneration, but none focus on explicitly returning the heart to pre-heart attack levels of function. The Roche lab has developed an epicardial patch that can mechanically reinforce the heart back to prevent it from progressing into heart failure after a heart attack , but current implantation methods are too invasive. In this study, researchers designed and developed a delivery tool that would adhere the hydrogel and composite based epicardial patches on infarcted hearts in a minimally invasive operation. The device is a collapsible and inflatable sleeve prototyped using thermoplastic polymer films and casted silicone rubber components, designed for minimally invasive subxiphoid surgery. It utilizes vacuum for stabilization during application. By characterizing the material properties with a universe mechanical tester, it was also found that the tool can reliably supply the necessary pressure to properly adhere the hydrogel patches. Through a series of ex vivo and in situ porcine experiments, it was found that the sleeve is effective at effectively positioning and adhering the patches to the epicardium. Such a tool would be helpful in applying therapeutics like the patch, presenting a low-cost, accessible solution for interventionalists. This delivery tool is still in development, as it is on its fourth iteration and in the future, would require extensive preclinical studies before moving into human trials..

Review of Membrane-Based Brackish Groundwater Desalination and Pretreatment in the United States

Tue, 01 Jun 2021 00:00:00 GMT

Review of Membrane-Based Brackish Groundwater Desalination and Pretreatment in the United States Klise, Flora Membrane-based brackish groundwater desalination increases freshwater supply, which is especially significant in arid, land-locked regions. Brackish groundwater is a widely available but underutilized alternative water source in the United States, where the risk of water scarcity is increasing in many areas. A primary limitation of brackish groundwater desalination is particulate accumulation called scaling on the membranes. By pretreating feedwater before desalination by filtering or adding chemicals, a plant can increase its efficiency and decrease total costs by increasing its recovery ratio and decreasing membrane maintenance costs. If left untreated, these scalants accumulate on the membranes and require costly removal treatment techniques. Pretreatment requirements vary with feedwater composition, geography, and technology. The associated capital, operating and maintenance costs of membrane-based brackish groundwater desalination plants with pretreatment in the United States are influenced by factors such as plant capacity, feedwater TDS and pretreatment requirements. Environmental costs include brine disposal and carbon-emitting energy usage.

Understanding changes in precipitation with climate change over wet and dry land

Tue, 01 Jun 2021 00:00:00 GMT

Understanding changes in precipitation with climate change over wet and dry land Weidman, Sarah Observed precipitation increased moderately in both wet and dry regions over the past 60 years, contradicting the wet-gets-wetter, dry-gets-drier (WWDD) mechanism. This study uses the perturbation atmospheric energy budget to understand the projected increase in precipitation over dry and wet land with climate change. Using global climate model output, the change in each term in the perturbation energy budget was calculated as a regional average over wet and dry tropical land. Increases in precipitation over wet and dry tropical land are primarily driven by increases in radiative loss, which are moderated by increases in sensible heat flux. Although the dry static energy flux divergence has a strong spatial pattern, cancellation between the horizontal and vertical advection terms, as well as cancellation between the dynamic and thermodynamic components of vertical advection, result in relatively small contributions from the dry static energy flux divergence towards the change in precipitation in the regional average. Only when wet and dry regions are allowed to change seasonally is WWDD given, suggesting that the movement of wet and dry regions is a significant factor in opposing the WWDD mechanism over land.

Collinear Supergravity at Linear Order

Tue, 01 Jun 2021 00:00:00 GMT

Collinear Supergravity at Linear Order Pramanik, Debaditya We review the concept of collinear superspace and reparametrisation invariance which we use to guide us in constructing collinear superspace Lagrangians. We describe the process of doing so for matter as well as gauge Lagrangians and note the similarities between the two. We use a similar approach to obtain a supergravity Lagrangian while using a non-conventional gauge fixing choice. The constructed Lagrangian maintains some similarities to the above two cases. We also identify the form of gauge field-current coupling as well as gravity-current coupling and note the similarities between the two couplings as well.

Competition among simulated plant species in a toy local vegetation model

Tue, 01 Jun 2021 00:00:00 GMT

Competition among simulated plant species in a toy local vegetation model Séguin, Azzo F. S. Kleidon and Mooney (2000) used a trait-based simulation of plants in the global environment to argue that the tropics maintain more biodiversity because a greater variety of strategies of allocation of functional parts, such as leaves and roots, lead to viable physiologies in those regions. However, they did not account for competition for resources, which often leads to competitive exclusion and thus to low diversity of plant types. Here we sought to revisit Kleidon and Mooney’s study by simplifying their modelling approach in a local mid-latitude temperate environment but including explicit competition for water. We hypothesized that competition would reduce potential biodiversity. We first explored the viability of 1000 randomly assigned strategies of allocation to roots, leaves and storage in this environment. After identifying individual plants that can survive in the local ecosystem, we investigated whether pairs of these viable species can stably co-exist in a 20 year simulation when competing for water. The toy model, though highly idealized, leads to plausible growth curves for isolated plants, although simulated plants are smaller and slower growing than real world plants. In isolation, 86% of allocation strategies were viable. In our framework, direct competition for water did not prevent coexistence for the majority of plant “species” that survived in isolation. The results are intriguing in the light of the competitive exclusion hypothesis. Next steps for examining our hypothesis more carefully include further development and calibration of the trait-based plant model and exploration of the climatic parameter space.

The Path Toward Racial Reconciliation in Salisbury, North Carolina

Tue, 01 Jun 2021 00:00:00 GMT

The Path Toward Racial Reconciliation in Salisbury, North Carolina Wahid, Miriam “Mimi” Imani In January 2019, the city council of Salisbury, North Carolina passed a resolution to renounce its past racial injustices, recognize the ways it has continued to uphold racial inequality, and work to improve equity in the future. The city, from a governmental level, promised to remedy its violent, racially divisive history and specifically renounced a lynching that occurred there in 1906. The Resolution wasn’t easy to pass, and spent months in revision, protest, and standstill. The process by which the Resolution was presented, revised, and eventually approved opens up the question of to what extent the Resolution has had, or will have, an impact on racial justice in Salisbury. This thesis also examines the ways that reconciliation is occurring in public space. In the three years since the resolution was first introduced, community members have been working with the Equal Justice Initiative’s Community Remembrance Project to erect a marker which memorializes the victims of racial terror in this town. The town has simultaneously engaged in a debate over its confederate monument, Fame. Through archival research, literature review, and narrative storytelling, I analyze the formal reconciliation process initiated in Salisbury as well as the role of memory, monuments, and markers in that work.

Characterization of clasts in the Glen Torridon region of Gale crater observed by the Mars Science Laboratory Curiosity Rover

Tue, 01 Jun 2021 00:00:00 GMT

Characterization of clasts in the Glen Torridon region of Gale crater observed by the Mars Science Laboratory Curiosity Rover Khan, Sabrina Y. Granule- to cobble- sized clasts in the Glen Torridon region of Gale crater on Mars were studied using data captured by the Mars Science Laboratory (MSL) Curiosity rover between martian days (’sols’) 2302 and 2593. The morphology and composition of clasts has the potential to reveal the nature and extent of erosional processes acting in a region. In this analysis, measurements of shape, size, texture and element abundance of unconsolidated clasts within lower Glen Torridon were compiled. Eight primary clast types were identified, all of which are sedimentary rock and can be linked to local bedrock, suggesting short transport distances. Several clast types exhibit signs of eolian abrasion, such as facets, pits, flutes and grooves. These results indicate that clasts are the products of bedrock degredation followed by extensive eolian wear.

Evaluating Beijing’s transit network expansion through a longitudinal analysis of the equity of public transit accessibility

Tue, 01 Jun 2021 00:00:00 GMT

Evaluating Beijing’s transit network expansion through a longitudinal analysis of the equity of public transit accessibility Guo, Alexander China’s rise as a global economic powerhouse brings with it enormous challenges to its ever-expanding megacities. Beijing, in particular, has experienced exponential growth in the last few decades, causing serious problems with traffic congestion, air quality, and sprawl. Planners have increasingly invested in public transit, particularly in subway and commuter rail, to solve these issues. This thesis investigates the effectiveness of such investment on the overall accessibility and equity of accessibility of public transit, for the past, present, and future. Using global satellite datasets for trip generation and a comprehensive graph of Beijing’s full, multi-modal transit system, including bus, subway, and commuter rail, this study calculates accessibility at a fine level and equity at a city-wide level, finding that although Beijing’s transit system is overall equitable, equity improvements from rural transit infrastructure are negated by increased decentralization of the city’s population and economic activities in recent years. As such, although equity of transit accessibility (ETA) has improved in general since 2006, this phenomenon has caused a noticeable deterioration in ETA recently and into the future, and serves as a strong argument to either reduce urban sprawl or accelerate Beijing’s transformation into a polycentric city with multiple, high-density urban cores linked by high-speed commuter rail.

Analysis of a solar oven for Pakistan

Tue, 01 Jan 1963 00:00:00 GMT

Analysis of a solar oven for Pakistan Lakhani, Husain Gulamhusain. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1963; Includes bibliographical references (leaf 29).

Angular distribution of [rho]-[pi] decay products of J/[psy]

Sat, 01 Jan 1994 00:00:00 GMT

Angular distribution of [rho]-[pi] decay products of J/[psy] Hales, David Scott. Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1994; On t.p., "[rho]," "[pi]," and "[psy]" appear as the lower case Greek characters.; Includes bibliographical references (leaf 47).

A determination of the live load on locomotive driving springs, under actual running conditions

Mon, 01 Jan 1906 00:00:00 GMT

A determination of the live load on locomotive driving springs, under actual running conditions Coes, H. V.; Howard, Christopher A. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1906

An investigation of the strain in reinforced-concrete beams of unusual depth

Fri, 01 Jan 1909 00:00:00 GMT

An investigation of the strain in reinforced-concrete beams of unusual depth Gilkison, G. M. (Gordon Mercer); Millard, R. W. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1909

The measles defect in CA-15 alloy steel castings

Wed, 01 Jan 1958 00:00:00 GMT

The measles defect in CA-15 alloy steel castings Fraunhofer, Harold G. An investigation was made to determine the effects of various mold variables on the surface condition of CA-15 alloy steel castings. This alloy often suffers from a peculiar defect known as measles, and an attempt was made to determine what reactions at the old-metal interface cause this defect. To this end, small cylindrical pins were rammed in sand molds and heated or melted in a small induction furnace. The type of sand and clay used were held constant while various atmospheres were provided in the mold flask. It was found that samples heated to 50°C below the melting point in an oxidizing atmosphere showed the characteristic measles defect encountered in casting CA-15 alloy in green sand molds. Samples melted, cooled to 50°C below the melting point, and held at that temperature in an oxidizing atmosphere showed a combination of the two defects. It was found that the measles defect is due to a liquid state reaction in which the chromium in the melt is oxidized to Cr₂O₃·Fe₂O₃ and Cr₂O₃·FeO. The mechanism was found to be akin to a pitting form of corrosion. The oxidizing atmosphere is provided by moisture in the molding material and carbon dioxide formed by the combustion of organic binders. Thesis: B.S., Massachusetts Institute of Technology, Dept. of Metallurgy, 1958; Cataloged from PDF version of thesis.; Includes bibliographical references (leaf 18).

Fluidity in pure aluminum and an aluminum-copper alloy

Wed, 01 Jan 1958 00:00:00 GMT

Fluidity in pure aluminum and an aluminum-copper alloy Blakely, Gary L.; Burgie, Richard R. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1958; Includes bibliographical references (leaf 24).

Variations in the cobalt based J alloy

Wed, 01 Jan 1958 00:00:00 GMT

Variations in the cobalt based J alloy Barone, Richard Vincent. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1958; Includes bibliographical references (leaf 33).

The observation of peak temperatures as a method of examining heat flow and metallurgical transformations due to a moving heat source in a metal plate

Wed, 01 Jan 1958 00:00:00 GMT

The observation of peak temperatures as a method of examining heat flow and metallurgical transformations due to a moving heat source in a metal plate Barber, James G. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1958

The desulphurization of grey cast iron by means of calcium carbide injection

Wed, 01 Jan 1958 00:00:00 GMT

The desulphurization of grey cast iron by means of calcium carbide injection Lynch, Peter F.; Aronson, Arthur Harry, 1935- Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1958; Includes bibliographical references (leaf 16).

Experimental investigations of the pressure distribution in a regenerative turbine pump, the Sta-Rite TH-7

Thu, 01 Jan 1953 00:00:00 GMT

Experimental investigations of the pressure distribution in a regenerative turbine pump, the Sta-Rite TH-7 Lutz, Gilbert F. (Gilbert Francis) Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1953; Includes bibliographical references (leaf 22).

The design and construction of test equipment for a regenerative

Thu, 01 Jan 1953 00:00:00 GMT

The design and construction of test equipment for a regenerative Taylor, Theodore.; Lippman, Daniel A. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1953; Includes bibliographical references (leaves ).

Local overheating during gasification of coke with air in a fluidized bed / by R.J. Weidman.

Thu, 01 Jan 1953 00:00:00 GMT

Local overheating during gasification of coke with air in a fluidized bed / by R.J. Weidman. Weidman, R. J. (Richard Joseph) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1953; Includes bibliographical references (leaf 34).

An investigation of the viscosity characteristics of Buna-N rubber in several solvent-non-solvent combinations

Thu, 01 Jan 1953 00:00:00 GMT

An investigation of the viscosity characteristics of Buna-N rubber in several solvent-non-solvent combinations Vieira, Herbert L. (Herbert Longworth) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1953; Includes bibliographical references (leaf 49).

Heat transfer in a batch fluidized bed

Thu, 01 Jan 1953 00:00:00 GMT

Heat transfer in a batch fluidized bed Miskinis, Richard T. (Richard Thomas) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1953; Includes bibliographical references (leaf 44).

Elemental sulfur from ferrous sulfide

Thu, 01 Jan 1953 00:00:00 GMT

Elemental sulfur from ferrous sulfide Leonard, Edward F. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1953; Includes bibliographical references.

The entrainment of solids from fluidized beds

Thu, 01 Jan 1953 00:00:00 GMT

The entrainment of solids from fluidized beds Hinds, Robert J. (Robert James) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1953; Includes bibliographical references.

The selection of the foundations for the Charles Hayden Library and the Eastgate apartments

Sun, 01 Jan 1950 00:00:00 GMT

The selection of the foundations for the Charles Hayden Library and the Eastgate apartments Dawson, Charles D. Thesis: B.S., Massachusetts Institute of Technology, Department of Building Engineering and Construction, 1950; Bibliography: leaf 13.

On the zirconium activities found in slow neutron fission of uranium

Sat, 01 Jan 1949 00:00:00 GMT

On the zirconium activities found in slow neutron fission of uranium Sakakura, Arthur Y. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemistry, 1949; Bibliography: leaf 26.

Absorption studies of metastable helium atoms.

Sat, 01 Jan 1966 00:00:00 GMT

Absorption studies of metastable helium atoms. Casperson, Lee W. (Lee Wendel), 1944- Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1966; Bibliography: leaf 38.

Aids for the design, acquisition, and use of large speech databases

Wed, 01 Jan 1986 00:00:00 GMT

Aids for the design, acquisition, and use of large speech databases Kassel, Robert H. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1986; Bibliography: leaves 27-28.

A performance analysis of the relational data management system.

Thu, 01 Jan 1976 00:00:00 GMT

A performance analysis of the relational data management system. Martin, Thomas Joseph. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1976; Includes bibliographical references.

The internal scattering of ultrasound by biological tissues

Thu, 01 Jan 1976 00:00:00 GMT

The internal scattering of ultrasound by biological tissues Mansfield, Ann Beth. Thesis: B.S., Massachusetts Institute of Technology, Department of Biology, 1976; Includes bibliographical references.

A study of propellers used on sailing auxiliaries.

Thu, 01 Jan 1976 00:00:00 GMT

A study of propellers used on sailing auxiliaries. Mango, Nicholas Kilduff. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1976; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.; Includes bibliographical references.

Vessel passage through straits : past, present, and future.

Thu, 01 Jan 1976 00:00:00 GMT

Vessel passage through straits : past, present, and future. Mar, Thomas Webb. Thesis: M.S., Massachusetts Institute of Technology, Department of Ocean Engineering, 1976; Bibliography: leaves 154-158.

The effect of steam at atmospheric pressure on cement mortars

Tue, 01 Jan 1918 00:00:00 GMT

The effect of steam at atmospheric pressure on cement mortars Salah, John S. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1918

A statistical social study of the Negroes of Cinclare Central Factory and Calumet Plantation, Louisiana

Tue, 01 Jan 1901 00:00:00 GMT

A statistical social study of the Negroes of Cinclare Central Factory and Calumet Plantation, Louisiana Laws, James Bradford. Thesis: B.S., Massachusetts Institute of Technology, Department of General Studies, 1901

Geology of Bradford oil rocks : some experiments pertaining to their structure and capacity to furnish petroleum

Thu, 01 Jan 1885 00:00:00 GMT

Geology of Bradford oil rocks : some experiments pertaining to their structure and capacity to furnish petroleum Newell, Frederick Haynes, 1862-1932. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1885

A country residence

Mon, 01 Jan 1906 00:00:00 GMT

A country residence Manning, Eleanor, 1884-1973. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1906

The geology of the Cape Ann granite

Wed, 01 Jan 1908 00:00:00 GMT

The geology of the Cape Ann granite Chipman, Kenneth G.; Maxwell, Jesse Worth. Thesis: B.S., Massachusetts Institute of Technology, Department of Mining Engineering and Metallurgy, 1908; Includes bibliographical references (leaf 95).

A votive chapel foring a subordinate element in a great cathedral - monastery scheme

Mon, 01 Jan 1912 00:00:00 GMT

A votive chapel foring a subordinate element in a great cathedral - monastery scheme Doane, Ralph Harrington, 1886-1941. Thesis: B.S., Massachusetts Institute of Technology, Department of Architecture, 1912

Illumination design for certain rooms of the Simplex Wire and Cable Company

Mon, 01 Jan 1917 00:00:00 GMT

Illumination design for certain rooms of the Simplex Wire and Cable Company Wallis, James E., B.S. Massachusetts Institute of Technology. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1917

Investigation of the characteristics of a two cylinder outboard motor

Sun, 01 Jan 1928 00:00:00 GMT

Investigation of the characteristics of a two cylinder outboard motor Dean, Walter B.; Francis, George E. Thesis: B.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1928

The manganese veins at West Cummington, Massachusetts

Sun, 01 Jan 1933 00:00:00 GMT

The manganese veins at West Cummington, Massachusetts Brashears, M. L. Thesis: B.S., Massachusetts Institute of Technology, Department of Geology, 1933; Includes bibliographical references (leaf 20).

A beach development

Sun, 01 Jan 1933 00:00:00 GMT

A beach development Kelly, Margaret B. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1933; Includes bibliographical references (leaf [33]).

Effect of storgae conditions on dried scallions

Mon, 01 Jan 1962 00:00:00 GMT

Effect of storgae conditions on dried scallions Song, Chokyun Rha. Thesis: B.S., Massachusetts Institute of Technology, Department of Food Technology, 1962; Includes bibliographical references (leaves 52-54).

Experiments on the buckling of skewed hyperbolic paraboloid shells

Tue, 01 Jan 1963 00:00:00 GMT

Experiments on the buckling of skewed hyperbolic paraboloid shells Efimba, Robert Elangwe. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1963; Includes bibliographical references (leaf 38).

A critical path program manual

Tue, 01 Jan 1963 00:00:00 GMT

A critical path program manual Champy, James A. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1963; Appendix contains numerous pamphlets.; Includes bibliographical references.

The LaGrange Country Club, LaGrange, Illinois

Fri, 01 Jan 1960 00:00:00 GMT

The LaGrange Country Club, LaGrange, Illinois Booth, Laurence D. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1960

An undergraduate dormitory for M.I.T.

Wed, 01 Jan 1958 00:00:00 GMT

An undergraduate dormitory for M.I.T. Turk, Theodore Michael. Thesis: B. Arch., Massachusetts Institute of Technology, Department of Architecture, 1958; Includes bibliographical references.

Voting rights for non-U.S. citizens in the City of Los Angeles

Sat, 01 Jan 1994 00:00:00 GMT

Voting rights for non-U.S. citizens in the City of Los Angeles Padilla, Alejandro (Composer) Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1994; Includes bibliographical references.

Determination of the equation of state constants for carbon dioxide

Thu, 01 Jan 1953 00:00:00 GMT

Determination of the equation of state constants for carbon dioxide Selby, Elmer E. (Elmer Everett) Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1953; Includes bibliographical references (leaf 30).

Industrial diversification in the Merrimac Valley : an analysis of recent community efforts

Tue, 01 Jan 1952 00:00:00 GMT

Industrial diversification in the Merrimac Valley : an analysis of recent community efforts Gillett, Richard B., 1926- Thesis: M.S., Massachusetts Institute of Technology, Department of Business and Engineering Administration, 1952; Includes bibliographical references (leaves 116-121).

The New Bedford Water Works

Mon, 01 Jan 1877 00:00:00 GMT

The New Bedford Water Works Lawton, C. F. Thesis: B.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1877

Coarse powder metallurgy.

Sat, 01 Jan 1966 00:00:00 GMT

Coarse powder metallurgy. Davison, Ralph Morgan. Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1966; Bibliography: leaf 37.

In defense of Mencken.

Wed, 01 Jan 1969 00:00:00 GMT

In defense of Mencken. Varteressian, Armen. Thesis: B.S., Massachusetts Institute of Technology, Department of Humanities, 1969; Bibliography: leaves 50-51.

Estimation of the thermal conductivity of polyatomic gases.

Sun, 01 Jan 1967 00:00:00 GMT

Estimation of the thermal conductivity of polyatomic gases. Hewitt, Robert Carlton. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1967; Bibliography: leaves [81]-86.

Anti-static nylon and Mylar surface via graft copolymerization.

Sun, 01 Jan 1967 00:00:00 GMT

Anti-static nylon and Mylar surface via graft copolymerization. Gomes Casseres, Ronald. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1967; Bibliography: leaves 66-67.

The effect of free volume on the radiation acceleration of creep in polycarbonates.

Sun, 01 Jan 1967 00:00:00 GMT

The effect of free volume on the radiation acceleration of creep in polycarbonates. Goldsmith, Andrew Harry. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1967; Lacking l. 50.; Bibliography: leaves 58-60.

Determination and evaluation of the permeability of membranes for the artificial kidney

Sun, 01 Jan 1967 00:00:00 GMT

Determination and evaluation of the permeability of membranes for the artificial kidney Galpin, Lawrence Burrowes. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1967; Bibliography: leaves 82-84.

Mathematical model of a cement rotary kiln.

Sun, 01 Jan 1967 00:00:00 GMT

Mathematical model of a cement rotary kiln. Farookhi, Riaz. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1967; Bibliography: leaves 65-66.

Modulation and coding for deep space probes.

Fri, 01 Jan 1965 00:00:00 GMT

Modulation and coding for deep space probes. Goldfein, Henry David. Thesis: B.S., Massachusetts Institute of Technology, Department of Electrical Engineering, 1965

Designing an instrument for cutting and removing vitreous membranes from human eyes.

Tue, 01 Jan 1974 00:00:00 GMT

Designing an instrument for cutting and removing vitreous membranes from human eyes. Numata, Tetsuto. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1974; Includes bibliographical references.

Design and applicability of a mechanical impedance sensor for vein penetration detection

Wed, 01 Jan 2020 00:00:00 GMT

Design and applicability of a mechanical impedance sensor for vein penetration detection Grown-Haeberli, Serena (Serena C.); Montague-Alamin, Healey.; Slocum, Alexander H.; Hanumara, Nevan Clancy.; Ramirez, Aaron Eduardo.; Connor, Jay.; Hom, Gim Poy.; Pott, Philipp H.; Stewart, Kent K. Intravenous needle insertion is typically conducted manually, with needles guided into vessels by feel while looking for a brief flash of blood. This process is imprecise and leads to mispositioned needles, multiple reinsertion attempts, increased procedure time and higher costs for the hospital. We present a method for indicating that the needle has reached the vein by measuring the change in mechanical impedance of the needle as it passes through different tissue layers. Testing in a phantom indicated that this has the potential to identify transitions through tissue boundaries. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, September, May, 2020; Cataloged from the official PDF of thesis. Thesis also published in: Serena Grown-Haeberli, Healey Montague-Alamin, Alexander Slocum, Nevan Hanumara, Aaron Ramirez, Jay Connor, Gim Hom, Peter Pott and Kent Stewart. "Design and Applicability of a Mechanical Impedance Sensor for Vein Penetration Detection." 2020 42nd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), 2020, pages 4016-4019, doi: 10.1109/EMBC44109.2020.9175501.; Includes bibliographical references.

Exploring crystallographic compatibility in polycrystalline Cu-based shape-memory alloys

Tue, 01 Jan 2019 00:00:00 GMT

Exploring crystallographic compatibility in polycrystalline Cu-based shape-memory alloys Payne, Madelyn (Madelyn I.) Shape-memory alloys (SMAs) are a class of materials that can recover from apparent permanent strain (on the order of 5%) due to a solid-to-solid phase transformation. It has been recently suggested that SMAs satisfying a set of so-called cofactor conditions possess perfect interface compatibility and additional microstructural flexibility during transformation, which are theorized to result in excellent reversibility. Cu-based SMAs are cheaper than other alternatives, but polycrystalline Cu-based SMAs are unable to withstand many cycles because they are prone to cracking and degradation of functional properties. Previous research has identied improved shape-memory properties in Cu-Al-Ni-Mn SMAs in the oligocrystalline state, but polycrystalline material of the same composition has yet to be characterized. In this thesis, I characterize the compatibility of Cu-Al-Ni-Mn alloys according to the cofactor conditions and correlate these findings with results from superelastic mechanical cycling. Building on this knowledge, I also present a new alloy design that is predicted to meet the cofactor conditions and provides a promising path forward for a functionally stable, low-cost, polycrystalline Cu-based SMA. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, June, 2019; Cataloged from the official PDF version of thesis.; Includes bibliographical references (pages 47-49).

Synthesis of perovskite-ceria composites for solar-to-fuel conversion

Mon, 01 Jan 2018 00:00:00 GMT

Synthesis of perovskite-ceria composites for solar-to-fuel conversion Aggarwal, Neil, S.B. Massachusetts Institute of Technology. Finding suitable replacements for fossil fuels is key to a more sustainable energy economy. This thesis investigated the effectiveness of novel composite materials made from previously researched state-of-the-art materials as catalysts in the thermochemical solar-to-fuel conversion process. Materials such as ceria and gadolinium-doped ceria (GDC) have been determined to have excellent kinetics for this process but have a very high operating temperature. In contrast, perovskites have the advantage of a lower operating temperature but it comes at the expense of lower production rates. Composites containing ceria/GDC/YSZ and perovskite were synthesized to explore synergies that may result in improved performance as a catalyst for the fuel conversion process. Two of these perovskite-ceria composites, LSCF-GDC and LSCC-ceria, showed promise as materials that perform better than their respective individual components. Improved fuel production and oxygen release was observed with these composites in specific temperature regimes (1000-1100°C for oxidation, 1200°C for reduction). Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, June, 2018; Cataloged from the PDF version of thesis. "June 2018."; Includes bibliographical references (page 30).

Increased biopolymer pigment production in bacteria and fungi exposed to ionizing radiation

Wed, 01 Jan 2020 00:00:00 GMT

Increased biopolymer pigment production in bacteria and fungi exposed to ionizing radiation Wilson, Sara L., S.B. Massachusetts Institute of Technology. A major concern for manned space missions is ionizing radiation, which is known to pose both acute and chronic risks to many organisms. It is critical to expand strategies for radiation protection, including utilizing new materials and fabrication methods designed to support and augment health and wellbeing. The Mediated Matter Group in the Media Lab is researching the application of pigments for biocompatible radioprotection. These pigments' properties--including both UV and ionizing radiation absorption--lend themselves to interesting potential applications in biomedicine and biotechnology¹,². Some bacteria and fungi respond to ionizing radiation with enhanced growth and pigment production, and they have been found in a variety of extreme and high radiation environments³. This thesis is an exploration of the potential of pigments, like melanins and carotenoids, to protect from and react to ionizing radiation in the context of space. Certain bacteria and fungi show a remarkable ability to persist, and even thrive, in high-radiation environments⁴. The bacteria of interest in this study are Bacillus subtilis and Rhizobium etli; the fungi of interest are Aspergillus niger, Neurospora crassa, and Xanthophyllomyces dendrorhous. These organisms form biopolymer pigments, including melanins and carotenoids, which may potentially have an important role in the radioresistance of the organisms⁵. For this reason, the Mediated Matter Group is conducting research both simulating and in space environments to understand the impact of radiation on biological systems and their adaptive strategies. In this work, we examine the growth and behavior of several species of bacteria and fungi while exposed to radiation to determine mechanisms by which they may adapt to these harsh conditions. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, May, 2020; Cataloged from the official PDF version of thesis. "May 2020."; Includes bibliographical references (pages 29-35).

Uniaxial optical phase change metamaterials

Wed, 01 Jan 2020 00:00:00 GMT

Uniaxial optical phase change metamaterials Ogunlade, Babatunde Olamide. Optical metamaterials are artificially engineered materials with exceptional electromagnetic properties that cannot be found in nature. Over the last 20 years, optical metamaterials have driven forward a plethora of fields from telecommunications to solar energy harvesting. They owe their unique optical properties to their carefully arranged subwavelength structural elements. By tuning the shape, geometry, and arrangement of these structures, unconventional optical properties like a negative refractive index can be achieved over a broadband wavelength range of operation. By incorporating optical phase change materials, materials with outstanding optical contrast upon a solid-state phase transition, more control over the optical modulative properties of metamaterials can be achieved. In this paper, Ge₂Sb₂Te₅ (GST) is chosen as a model phase change material due to its high reflectance contrast between states, fast switching speeds, and high metastability. Here, we theoretically investigate the reflectance and form birefringence of GST-based optical metamaterials. These optical properties are simulated on the basis of effective medium theory (EMT) and transfer matrix method (TMM). The findings in this paper demonstrate that broadband wavelength regions of high reflectance, high birefringence, and zero-crossing birefringence can be found and tuned as a function of material thickness and fill fraction in simulated GST-based optical metamaterials. These findings will be valuable for imminent nano and microfabrication in optical devices. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, May, 2020; Cataloged from the official PDF version of thesis.; Includes bibliographical references (pages 23-24).

Development and research of porous alumina xerogel membranes for electrospray propulsion applications

Wed, 01 Jan 2020 00:00:00 GMT

Development and research of porous alumina xerogel membranes for electrospray propulsion applications Hannahs, Maia Hall. Electrospray engines have been under development at the MIT Space Propulsion Laboratory (SPL) for many years. The operating principle of electrospray engines is a voltage drives a charged liquid fuel through an extractor membrane, the momentum of the exiting fuel is what propels the engine. The extraction membrane must have a specific geometry of an array of tips to allow for the amount and direction of the fuel emitted to be controlled. The membrane also must not react with the fuel under high voltages, and must be stable in the extreme conditions of space. Therefore this thesis discusses the past materials which have been used as candidates for this application and a discussion of electrospray performance in comparison to other forms of electric propulsion. The experimental section specifically focusses on cast alumina xerogels (porosities less than 90% typically around 40-50%) and briefly investigates a manufacturing procedure. The main problem facing the performance of these extractor membranes is the consistency of their geometry and porosity given the manufacturing constraints to make these engines easily scalable and relatively cheap. Xerogels are prepared through the sol-gel method can be cast into the emitter tip array, are synthesized from a liquid solution, and their porosity and total density can be affected through the drying conditions or sintering. To simplify the manufacturing process these samples were allowed to dry slowly by partial exposure to air. Many of the samples cracked but also exhibited very uniform pore size and distribution. So a discussion of possible ways to best control the solvent removal without straining the structure follows, as well as a discussion of possible characterization methods. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, May, 2020; Cataloged from the official PDF version of thesis. "May 2020."; Includes bibliographical references (pages 36-38).

Simulating and calibrating stretchable optical fibers for studying neural dynamics

Wed, 01 Jan 2020 00:00:00 GMT

Simulating and calibrating stretchable optical fibers for studying neural dynamics Shi, Cindy H. Study of the central nervous system (CNS) in freely-moving animal behavior experiments is greatly limited by the materials available for neural probing and optical recording, such as silica, which are stiff and can damage neural tissue with vigorous test subject movement. In this work, we develop a polyvinyl alcohol (PVA) hydrogel optical fiber for photometric recording of neural dynamics that is flexible and stretchable, leading to minimal harm to surrounding brain tissue. The hydrogel fiber fabrication method is optimized for highest refractive index and lowest autofluorescence for best signal recording precision, and further customized to allow chemical delivery to the fiber implantation site via either payload adsorption and diffusion through a porous outer layer of the fiber or an embedded polytetrafluoroethylene (PTFE) fluidic channel along the side of the PVA hydrogel. Absorption swelling and kinetics of the nonporous and porous fibers are characterized experimentally and backed by theoretical analysis. PVA-PTFE composite fiber curling during drying due to mismatched material swelling behavior is also theoretically modelled to determine the constraining force needed to keep the fiber straight for better surgical precision, and a fiber straightening device is designed for this purpose. To demonstrate the optical recording capability of this flexible fiber, the nonporous PVA hydrogel is implanted into the ventral tegmental area of the mouse deep brain, along with a viral injection containing fluorescence-expressing gene GCaMP6s, mouse social behavior tests with simultaneous photometry recording are conducted up to 2 months after implantation, and resulting photometric curve amplitudes are analyzed to distinguish between neural activity during social and nonsocial interaction. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, May, 2020; Cataloged from the official PDF version of thesis.; Includes bibliographical references (page 30).

Hydrological disasters : designing to shelter in place

Fri, 01 Jan 2021 00:00:00 GMT

Hydrological disasters : designing to shelter in place Gonzalez- Placito, Alejandro. The focus of this thesis is hydrological disasters and the question it attempts to answer is: how can we design and implement housing structures along U.S. coastlines that fully withstand hydrological disasters? Priority and severity is shown by increasing trends in natural disaster occurrence frequency and damage and reconstruction costs. Cost increase is due in part because disaster events are more destructive, but also because of overbuilding and high housing density located within high risk areas. First, using several literature sources, this thesis analyzes various aspects of natural disaster response and education. This paper achieves its goal to increase awareness about the flaws in government risk management and lack of disaster awareness and mitigation design curricula amongst architecture institutions. As a design thesis, alternative housing models are presented in the later sections. The design process begins with hazard-risk identification and then outlining important building regulations. FEMA Coastal Construction Manual along with other sources were useful in understanding necessary mitigation measures required for coastal development designs. After research, a new design solution is presented. Design inspiration was drawn from similar technology and the need for innovative, resilient, and economical designs. This thesis hopes to use idealized designs to start more conversation about natural disaster defensive architecture. Thesis: S.B. in Art and Design, Massachusetts Institute of Technology, Department of Architecture, February, 2021; Cataloged from the official pdf version of thesis.; Includes bibliographical references (pages 49-50).

Experimental validation of the predicted emergent magnetism in diamagnetic cadmium sulfide (Cds) doped with boron

Wed, 01 Jan 2020 00:00:00 GMT

Experimental validation of the predicted emergent magnetism in diamagnetic cadmium sulfide (Cds) doped with boron Azhar, Bilal. The large and persistent photoconductivity displayed by some semiconductors provides a way to control magnetism with light, through illumination-control of free carrier concentration and thereby magnetic interaction in dilute magnetic semiconductors. CdS is a wide band-gap semiconductor that displays large and persistent photoconductivity and is predicted to become magnetic when doped with certain dopants such as Boron[1]. In this work, we experimentally test the prediction of magnetic CdS:B, and lay groundwork for testing the hypothesis that magnetism can be controlled by photoconductivity. We make CdS:B nanoparticles by co-precipitation[2]. We use X-ray diffraction and plasma optical emission spectroscopy to quantify boron doping. We use magnetometry to confirm the presence of magnetic B. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, May, 2020; Cataloged from the official PDF version of thesis.; Includes bibliographical references (pages 41-42).

Analytical and numerical study of the unstable limit cycles of walking droplets

Wed, 01 Jan 2020 00:00:00 GMT

Analytical and numerical study of the unstable limit cycles of walking droplets Kurzban, Benjamin(Benjamin A.) Recent studies have shown that a vibrating fluid bath can support a bouncing droplet, generating a pilot wave which propels the droplet into horizontal motion. Walking droplets have been demonstrated not only to follow linear trajectories, but to exhibit a range of rich dynamical behavior, including tunneling, diffraction, and orbital quantization. Current theoretical models for the walking droplet system can be difficult to analyze. Here, by reducing the dimension of the bath, a simpler model has been derived and analyzed. We summarize this derivation, explore the stability of the system's dynamical states, and provide evidence of a previously unreported homoclinic bifurcation. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, September, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 8).

Mechanical properties of gels formed by nickel and cobalt complexation with histamine-grafted polyisoprene and polystyrene in non-aqueous solvents

Wed, 01 Jan 2020 00:00:00 GMT

Mechanical properties of gels formed by nickel and cobalt complexation with histamine-grafted polyisoprene and polystyrene in non-aqueous solvents Laris, Omar A. Leveraging metal-coordination crosslinks for materials design of polymers can enable fine-tuning of the mechanical properties of rubbers without requiring the use of sophisticated vulcanization pathways. In this work, we synthesized several polyisoprene-graft-histamine gels in toluene, coordinated by Ni²⁺ and Co²⁺ ions. In addition, we synthesized polystyrene-graft-histamine-Ni(OH)₂ composites in DMF, with Ni(OH)₂ nanoparticles nucleated and grown in situ upon the addition of a hydroxide. The viscoelastic mechanical properties of these materials are improved relative to the base polymers. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, May, 2020; Cataloged from the official PDF version of thesis.; Includes bibliographical references (page 28).

Analysis of patent data for flame-retardant plastics additives

Wed, 01 Jan 2020 00:00:00 GMT

Analysis of patent data for flame-retardant plastics additives Mulcahy, Ciara(Ciara Renee) Plastics are commercially produced by selecting a polymer resin and incorporating chemical additives to affect specific mechanical, chemical or aesthetic properties of the plastic products. The number of possible combinations of polymers and additives yields an enormous engineering space to meet the design requirements of the many applications of plastic materials. However, the broad scope of plastics science hinders both the invention of new plastics formulations and efforts to investigate potentially harmful polymer resins and plastic additives. In this thesis, a method of representing and analyzing the claims section of patents is presented and applied to a set of patents that refer to flame retardants. The claims section of a patent is presented as a graph, with individual claims as points and references between claims as lines connecting those points.; The chemical terms mentioned in the text of each of the claims were split into individual words or short sequences of words, called "tokens", by an existing materials tokenizer that had been trained on scientific journal articles. The term frequency - inverse document frequency (tf-idf) statistic for each token within each claim was computed, using the entire claims section of the individual patent to calculate the document frequency. Each claim was attributed the tokens that had tf-idf scores greater than the highest-scoring term shared with a claim to which that claim referred. By researcher inspection, this method served to extract relevant chemical terms, while omitting words that did not contribute to the chemical relevance of the claim or patent as a whole. A visualization of these labelled graphs of the claims was generated.; This reduced, graphical representation of materials patents could be implemented to aid in researcher review or computational tasks to survey for chemical components or resin-additive compatibilities. Such a representation of patent data could make the prioritization and review of commercial chemicals a more tractable task. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, May, 2020; Cataloged from the official PDF version of thesis.; Includes bibliographical references (pages 33-35).

Synthesis of guanidinium-functionalized amphiphiles for the exploration of chaotropic supramolecular nanoribbons

Fri, 01 Jan 2021 00:00:00 GMT

Synthesis of guanidinium-functionalized amphiphiles for the exploration of chaotropic supramolecular nanoribbons Grey-Stewart, Danielle(Danielle N.) Nanoscale self-assembly driven by the hydrophobic effect is of intense research interest due to the ability to synthesize complex, chemically diverse structures with molecular length scales. Supramolecular self-assemblies comprised of amphiphilic molecules have been engineered to achieve diverse applications, from drug delivery to 3D printing. The design of the component molecules in engineered assemblies are often bio-inspired, where structures are highly dynamic to respond to changes in their environment. Molecules within dynamic assemblies move rapidly due to molecular exchange and rearrangement, and the supramolecular structure is often only retained for a limited amount of time before breaking down. Aromatic amide (aramid) amphiphiles, which can form strong hydrogen bonding and pi-pi stacking between them, self-assemble into stable, mechanically strong nanofibers, in stark contrast to the assemblies that precede them. This study seeks to functionalize the aramid amphiphile nanofibers surface for the study of water dynamics by attaching a chaotropic guanidinium head group. This head group will disturb the hydrogen bonding network of surrounding water, causing a measurable change in water dynamics when analyzed using Overhauser Dynamic Nuclear Polarization. Guanidinylation was achieved, but future work must be done to create a kosmotropic analog. These two structures will be used to run parallel experiments to study the water dynamics in the local environment. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, February, 2021; Cataloged from the official PDF version of thesis.; Includes bibliographical references (pages 28-30).

Feeding Rome : innovation in the economy of the Roman grain supply

Wed, 01 Jan 2020 00:00:00 GMT

Feeding Rome : innovation in the economy of the Roman grain supply James, Alden(Alden T.) Thesis: S.B., Massachusetts Institute of Technology, History Section, May, 2020; Cataloged from the official PDF version of thesis.; Includes bibliographical references (pages [56]-[57]).

Production of phosphorus alloys through thermal reactions and electrochemical reduction of molten apatite

Wed, 01 Jan 2020 00:00:00 GMT

Production of phosphorus alloys through thermal reactions and electrochemical reduction of molten apatite Richardson, Caleb,1792?-1820. A process for extracting phosphorus from fluorapatite through high temperature electrochemical means. Theoretical modelling and calculations show that P-alloys can be manufactured directly from decomposed molten fluorapatite. Nickel-phosphide is chosen as an examplary alloy both for its incredible thermodynamic stability and for its mechanical properties. Molten hydroxyapatite decomposes as it melts into two solid phosphorus rich phases, tricalcium phosphate and tetracalcium phosphate. Fluourapatite behaves in a similar manner, albeit at a higher temperature. These two calcium phosphates can be reduced to calcium oxide and oxygen in the presence of nickel, forming Ni₃P. Included in this paper is an in-depth overview of current and past phosphorus reduction methods and a discussion of their improvement. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, May, 2020; Cataloged from the official PDF version of thesis.; Includes bibliographical references (pages 32-34).

Multi-scale investigations of the Resistance to helium embrittlement with Direct Energy Deposited Inconel 718

Fri, 01 Jan 2021 00:00:00 GMT

Multi-scale investigations of the Resistance to helium embrittlement with Direct Energy Deposited Inconel 718 Stapelberg, Myles Graham. To address the high levels of helium production in advanced fission and fusion reactors, in an economical manner, Direct Energy Deposition (DED) was utilized with the existing alloy, Inconel 718. Based on previous works with DED and laser welding, it was hypothesized that nano-sized pores could be engineered within the matrix of the sample to maximize the number of available sinks for helium bubbles to migrate towards, instead of migrating towards grain boundaries. A sparse experimental matrix with 316L Stainless Steel, followed up with 2-Factor, 3 Level full factorial experiments with Inconel 718 was conducted to understand the input parameters for engineering nanoporosity. In-situ ion irradiation TEM was conducted to analyze the helium bubble kinetics in real time at the nanoscale and ex-situ ion irradiation followed by Vicker's microhardness tests, X-ray Diffraction, Energy Dispersion Spectroscopy, and Focused Ion Beam Analysis were conducted to gauge the effectiveness of the printed sample at inhibiting helium migration and embrittlement. Due to insufficient measurements and the sensitivity of Inconel 718's microstructure to temperature, no significant change between the control and helium implanted specimens were observed at the micro scale. However, at the nanoscale, nanopores were found and were able to suppress the nucleation of helium bubbles. As such, a followup study, investigating nuisance factors discussed in this work is warranted to better assert whether or not DED can effectively reduce the effects of helium embrittlement. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, February, 2021; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 101-114).

The politics and perceptibility of breath during the COVID-19 pandemic

Fri, 01 Jan 2021 00:00:00 GMT

The politics and perceptibility of breath during the COVID-19 pandemic Shah, Vaibhavi(Vaibhavi B.) Thesis: S.B., Massachusetts Institute of Technology, Program in Science, Technology and Society, February, 2021; Cataloged from the official PDF version of thesis.; Includes bibliographical references (pages 56-62).

Motional state engineering for continuous-variable quantum computation

Fri, 01 Jan 2021 00:00:00 GMT

Motional state engineering for continuous-variable quantum computation Mintzer, Gabriel L. The standard approach to quantum computation uses qubits, which are well-described as a two-level system. An alternative approach to quantum computation is continuous-variable quantum computation (CVQC), which uses physical observables, such as the strength of an electromagnetic field or the position of a particle in space, whose numerical values belong to continuous intervals. Trapped ions are well-developed for quantum computation, and they possess both qubit and continuous degrees of freedom that can be precisely controlled, making them a good candidate for a realization of CVQC. Although there exist software frameworks capable of simulating CVQC experiments, these frameworks do not incorporate realistic noise sources and cannot be tailored to a specific trapped-ion setup. In this work, we develop a computational framework for simulating CVQC operations using trapped ions in a realistic system with realistic noise sources. We do so first with ideal Hamiltonians and then with Hamiltonians generated directly from the electric potential and fields that can be applied to the trapped ion in a representative Paul trap. This allows for the direct simulation of a squeezing operation that can be implemented through application of voltages in trapped-ion experiments. These methods can be applied to other CVQC operations in order to allow for their direct simulation as well. We package these tools into a usable application with which we can load information about an experimental configuration and then use this simulation procedure to design and test experiments in CVQC achievable with an ion-trap setup, thus facilitating the experimental design process and eventually allowing for prediction of system behavior and comparison with experimental results. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, February, 2021; Cataloged from PDF of thesis.; Includes bibliographical references (pages 61-63).

Noble Hills : settler colonialism and the making of the Lick Observatory, 1846-1919

Wed, 01 Jan 2020 00:00:00 GMT

Noble Hills : settler colonialism and the making of the Lick Observatory, 1846-1919 Minsky, Charlotte(Charlotte L.) Thesis: S.B., Massachusetts Institute of Technology, History Section, May, 2020; Includes bibliographical references (pages 46-48).

Design of a virtual environment for physiological and subjective monitoring of user presence in VR

Wed, 01 Jan 2020 00:00:00 GMT

Design of a virtual environment for physiological and subjective monitoring of user presence in VR AlAlawi, Marwa. User presence is a natural construct of the human psyche that is central to VR development. If analyzed well, presence can indicate the effectiveness of VR settings on amplifying a user's sense of 'being' in the environment. Consequently, allowing VR developers to save time and money. Several methods of measuring presence exist, and are classified as subjective or objective, with the latter being the most omnipresent. This paper discusses the process of designing a VR environment for subjective and objective presence measurement. The main physiological cue this study aims to inspect is grip-force, and its possible consistency with changes in other physiological responses, such as heart rate and respiratory response. In order to engender measurable variations in grip-force, the developed VE was designed to incorporate a gripping task for consistent grip-force feedback, and a virtual height stimulus to evoke objective physiological changes. The environment consisted of three stages: a training stage, a transition-to-stimulus stage, and a stimulus stage. Based on initial user testing, it was concluded that a virtual height situation with an environment disconnect between the training stage and the stimulus stage induced subjective stress. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis. "Due to the COVID-19 outbreak, user testing was halted and we were unable to proceed with the experiment. We hope to resume our data collection once the outbreak ceases"--Abstract page.; Includes bibliographical references (pages 52-55).

An accelerated K[subscript ISCC] test for high-strength steels in hydrogen

Tue, 01 Jan 1980 00:00:00 GMT

An accelerated K[subscript ISCC] test for high-strength steels in hydrogen Conley, Helen T. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1980; Includes bibliographical references.

Read and do with the Animaroos(tm) / by Amilcar Fuertes.

Sat, 01 Jan 2000 00:00:00 GMT

Read and do with the Animaroos(tm) / by Amilcar Fuertes. Fuertes, Amilcar,1976- Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2000

Cogeneration system size optimization and return on investment study

Sun, 01 Jan 1984 00:00:00 GMT

Cogeneration system size optimization and return on investment study Mayer, Kevin Andrew. Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1984; Bibliography: leaf 74.

The effect of unbalanced voltages on the operation of a three phase synchronous motor

Tue, 01 Jan 1924 00:00:00 GMT

The effect of unbalanced voltages on the operation of a three phase synchronous motor Hunter, John McN. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering, 1924.; Includes bibliographical references (leaf [72]).

The geology of Spencer Mountain, Somerset Co., Maine

Sun, 01 Jan 1961 00:00:00 GMT

The geology of Spencer Mountain, Somerset Co., Maine Baker, David W.(David Warren),1939- Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Geology, 1961.; Includes bibliographical references (leaf 27).

The synthesis of methane from blue water gas with a fluidized catalyst bed

Thu, 01 Jan 1953 00:00:00 GMT

The synthesis of methane from blue water gas with a fluidized catalyst bed Schwarz, Eric G.(Eric George) Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1953.; Includes bibliographical references (leaf 64).

A review of the environmental impacts of meat and meat alternatives

Wed, 01 Jan 2020 00:00:00 GMT

A review of the environmental impacts of meat and meat alternatives Das, Neel,S.B.(Neel K.)Massachusetts Institute of Technology. Awareness of the personal impacts individuals have on the environment is increasing in the United States. There are many different trends in the perception of how individuals can reduce their environmental impact. Examples include using metal straws instead of plastic straws, driving an electric car instead of a gas car, and eating meat alternatives instead of meat. This study primarily investigates the environmental impact of eating meat alternatives instead of meat. Life cycle analyses of the two most common meat alternatives--the Beyond Burger and the Impossible Burger-- were compared to life cycle analyses of beef. Life cycle analyses indicate that meat alternatives have significantly fewer GHG emissions than meat does. The LCA for the Impossible burger reports a 89% reduction in CO₂eq emissions over beef, while the Beyond Burger LCA reports a 90% reduction in CO₂eq emissions over beef. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from student-submitted PDF of thesis.; Includes bibliographical references (pages 29-32).

Harnessing thermoacoustics for waste heat recovery

Wed, 01 Jan 2020 00:00:00 GMT

Harnessing thermoacoustics for waste heat recovery Aguilar, Alex. Environmental concerns and economic incentives have created a push for a reduction in emissions and an increase in efficiency. The U.S. Department of Energy estimates that 20 to 50% of the energy consumed in manufacturing processes is lost in some form to waste heat. The purpose of this study is to review the waste heat recovery technologies currently available in both commercial and research applications to determine how thermoacoustics may serve a role in furthering the use of waste heat recovery units. A literary review of the most common waste heat recovery units was compiled to determine the advantages and disadvantages of the different technologies by comparing components and their governing processes. An existing model of a thermoacoustic converter (TAC) was reviewed and a conceptual analysis written to suggest improvements for future experimental designs. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, September, 2020; Cataloged from student-submitted PDF of thesis.; Includes bibliographical references (pages 25-26).

Studying the atmosphere of HD 189733 b using the Rossiter-McLaughlin effect

Wed, 01 Jan 2020 00:00:00 GMT

Studying the atmosphere of HD 189733 b using the Rossiter-McLaughlin effect Minsky, Charlotte(Charlotte L.) Transmission spectroscopy is a widely-used method for studying exoplanetary atmospheres. However, the differential data analysis techniques that are generally applied to high-resolution ground-based spectroscopic data are only sensitive to narrow spectral features and do not preserve broadband features. This makes them insensitive to the strong Rayleigh scattering slope of HD 189733 b that is due to possible atmospheric aerosols. The Rossiter-McLaughlin (RM) effect provides a way to probe broadband spectral features because its amplitude varies as a function of wavelength according to the effective planet radius. Previously, radial velocity (RV) variations caused by the RM effect were interpreted as being a tentative detection (2.5[sigma]) of the broadband scattering slope of HD 189733 b. We developed a new method that directly models the distortions in spectral lines (rather than the resulting RV variation) and applied this method to the same archival HARPS data that was used in the previous tentative detection. Here we will present this method and the ongoing work necessarily to problem-solve and fully implement it. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, May, 2020; Cataloged from student-submitted PDF of thesis. "May 21 2019."; Includes bibliographical references (pages 29-32).

Designing for focus in a distracted world : a proposal for new design heuristics

Wed, 01 Jan 2020 00:00:00 GMT

Designing for focus in a distracted world : a proposal for new design heuristics Zhang, Annie Tianci. People feel happy when deeply focused on something meaningful. Yet, it is increasingly difficult to focus in our attention-extractive economy because the technology driving our consumer products exceeds our human vulnerabilities. Cognition research has long shown that constantly being distracted by our devices decreases our performance on complex tasks and deteriorates our emotional health. So far, attempted solutions (such as screen usage limits) have largely placed the responsibility of corrective action on the user. However, when it comes to more traditionally harmful products, the responsibility lies with product designers to design less harmful products and warn users of risks. Why should it be any different for our devices The responsibility still lies with the product designers to create products that don't exploit our cognitive vulnerabilities. However, designers have no framework to follow. Designers are currently generating concepts based on short-sighted design heuristics (guidelines) that aim to reduce product failure and user confusion when using the product. Instead of only considering functionality, we need a framework to turn us toward the freedom of focus. New heuristics should be introduced that help us prioritize the protection of our minds and allow users to reclaim their control of their attention. This research details a process for discovering new focus-oriented design heuristics, as well as a proposal for 10 focus-oriented heuristics that have been demonstrated to improve the quality of concepts generated by junior designers. Thesis: S.B. in Art and Design, Massachusetts Institute of Technology, Department of Architecture, May, 2020; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 19-20).

LIVING TINY

Wed, 01 Jan 2020 00:00:00 GMT

LIVING TINY Jia, Effie. Living Tiny is a thesis that explores the role of architecture as a tool for designing both the built environment as well as the social realm of living. In a rapidly urbanizing world, the current pattern of city development results in unwanted isolation, expensive housing prices, and unsustainable growth. Can alternative forms of densification produce more appealing economical, social, and environmental results? This thesis proposes a design that builds upon the already existing infrastructure of alleyways and streets of typical urban neighborhoods. Through the implementation of a secondary scale, a new housing typology can emerge that satisfies the needs of the missing middle. Based on case studies of tiny houses and cohousing principles, Living Tiny envisions a two-part system of collective living that involves tiny house accessory dwelling units (ADUs) and communal buildings for shared amenities. Sited in Austin, Texas, the thesis presents its design for Mueller Tower District, a neighborhood featuring mixed-use zoning and a variety of housing typologies. The envisioned community benefits not only from the increased affordability and sustainability of living, but also from a greater quality of life through social interactions with the people around them. Through thoughtful, human-based architecture, cities of the future can avoid becoming concrete jungles; instead, they can become vibrant communities that support diverse, interconnected populations. Thesis: S.B. in Art and Design, Massachusetts Institute of Technology, Department of Architecture, May, 2020; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 59-61).

Design for a residence in the Italian Renaissance style

Mon, 01 Jan 1912 00:00:00 GMT

Design for a residence in the Italian Renaissance style Kebbon, Harold Eric. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1912.

Recording and processing data from transient events

Fri, 01 Jan 1988 00:00:00 GMT

Recording and processing data from transient events Westlund, Kenneth P.(Kenneth Peter) Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1988.; Includes bibliographical references.

Performance impact of ion sources in Inertial Electrostatic Confinement devices

Wed, 01 Jan 2020 00:00:00 GMT

Performance impact of ion sources in Inertial Electrostatic Confinement devices Calburean, Alexandru D. In order to improve the performance of Inertial Electrostatic Confinement (IEC) based fusion devices, so as to improve their effectiveness as low cost, portable neutron sources, a novel use of ion sources is proposed as a means of increasing fusion reaction rate at similar power levels. This paper aims to determine the success and practicality of the proposed use type for ion sources and characterize the IEC device in question, in terms of performance, and neutron emission. The application outlined aims to improve upon the performance of IEC devices with an anode layer ion source. The above-mentioned approach was evaluated by first conditioning the IEC fusion device in question. Then a neutron flux baseline was recorded as a metric for performance, and to evaluate the assumption of neutron emission isotropy in the device. Then an ion source was installed in the chamber, and the system was once again conditioned in the same manner. A similar baseline reading and analysis was done to ensure a correct comparison could be made between performance with the ion source turned on and off. Next the system was run with the ion source at full power to allow for further characterization of the performance and stability of the device. Finally, a last run was carried out with the ion source properly tuned, and results were compared to both baseline runs. It has been shown that there is a potential performance gain from operation with an ion source, both in terms of system stability and improved neutron emission. Across all run campaigns, the assumption of isotropic emission was shown to be a poor representation of the actual emission. With a higher degree of certainty, it has been shown that operation with an ion source serves to reliably exaggerate the anisotropy found in baseline campaigns. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, February, 2020; Cataloged from student-submitted PDF of thesis. "February 2020."; Includes bibliographical references (pages 38-39).

Flying boat design from a naval architect's point of view

Tue, 01 Jan 1924 00:00:00 GMT

Flying boat design from a naval architect's point of view Bozzano, Jose A. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Naval Architecture and Marine Engineering, 1924.; Includes bibliographical references (leaves 51-52).

Theoretical and practical devolopment (i.e. development) of a transmission dynamometer

Thu, 01 Jan 1953 00:00:00 GMT

Theoretical and practical devolopment (i.e. development) of a transmission dynamometer Kingsbury, E. P.(Edward P.) Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1953.

Cold drawing of austenitic stainless steel wire

Thu, 01 Jan 1953 00:00:00 GMT

Cold drawing of austenitic stainless steel wire Howard, James Henry. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1953.; Includes bibliographical references (leaf 16).

A method to determine the performance of a natural-circulation evaporator

Thu, 01 Jan 1953 00:00:00 GMT

A method to determine the performance of a natural-circulation evaporator Herrera y Castro, Edmundo N.(Edmundo Nelson) Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1953.; Includes bibliographical references (leaf 61).

Cation adsorption on clay surfaces

Thu, 01 Jan 1953 00:00:00 GMT

Cation adsorption on clay surfaces Rice, William L'Amoureax Robert. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1953.; Includes bibliographical references (leaves 44-45).

Finished product standardization in the stationary air compressor industry

Mon, 01 Jan 1951 00:00:00 GMT

Finished product standardization in the stationary air compressor industry O'Brien, John D.; Rooks, Albert H. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Business and Engineering Administration, 1951.; Bibliography: leaf 88.

Interfacing the Mattel Power Glove to a personal computer and evaluating its capabilities as a three-dimensional position sensor

Tue, 01 Jan 1991 00:00:00 GMT

Interfacing the Mattel Power Glove to a personal computer and evaluating its capabilities as a three-dimensional position sensor Chen, Eugene Samuel. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1991.; Includes bibliographical references (leaf 80).

The hydrodynamic permeability of sclera

Tue, 01 Jan 1991 00:00:00 GMT

The hydrodynamic permeability of sclera Chen, Anthia Yenshiu. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1991.; Includes bibliographical references (leaves 30-31).

A FAX application for the NeXT computer

Tue, 01 Jan 1991 00:00:00 GMT

A FAX application for the NeXT computer Chee, Yi-Min. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1991.; Includes bibliographical references (leaves 65-66).

Cheveux crépus et identité : démêler les attitudes des femmes d'origine africaine vis-à-vis de leurs cheveux

Tue, 01 Jan 2019 00:00:00 GMT

Cheveux crépus et identité : démêler les attitudes des femmes d'origine africaine vis-à-vis de leurs cheveux Yakpo, Sefa A. This thesis concerns the question of the relationship that women of African origin have with their hair. Based on an analysis of the perceptions and attitudes of these women towards their hair, the thesis attempts to answer the question: what standards do they hold for their hair, and what factors contribute to that? To respond to these questions, I analyze two media sources created by African women, for a female, African audience -- postcolonial-era magazine, AWA: la revue de lafemme noire, and the modern-day YouTube channel of a young Franco-Senegalese woman, Aïcha Danso. The analysis raises questions about identity and its construction, and the meanings hair holds for black women. It leads to the hypothesis I propose: that natural, kinky hair is fundamentally racialized, and that the ways in which black women choose to style it -- although imbued with meanings that are multidimensional, profound, and personal -- come under structural factors such as the ideals of feminine beauty. Thesis: S.B., Massachusetts Institute of Technology, MIT Global Studies and Languages, 2019; Cataloged from PDF version of thesis. "February 2019." Vita.; Includes bibliographical references (pages 67-69).

Recent developments in cost policies and methods in New England contracting organizations

Wed, 01 Jan 1930 00:00:00 GMT

Recent developments in cost policies and methods in New England contracting organizations Horton, Claude F.; Horton, Dwight. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Business and Engineering Administration, 1930.; Includes bibliographical references (leaf 99).

Proposal for high temperature - high rate convection billet reheating furnace

Mon, 01 Jan 1951 00:00:00 GMT

Proposal for high temperature - high rate convection billet reheating furnace Schultz, George E. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mechanical Engineering, 1951.; Bibliography: leaf 36.

Electric drive applications for hydrofoil ships

Sat, 01 Jan 1983 00:00:00 GMT

Electric drive applications for hydrofoil ships Ahearn, Leo Francis. Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1983.; Includes bibliographical references.

An experimental study of a pneumatic jet-pipe valve controlled servomechanism

Tue, 01 Jan 1963 00:00:00 GMT

An experimental study of a pneumatic jet-pipe valve controlled servomechanism Nanavati, Harit M. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1963.; Includes bibliographical references (leaf 28).

A theoretical and experimental investigation of the performance of some short flues under steady-state conditions

Mon, 01 Jan 1951 00:00:00 GMT

A theoretical and experimental investigation of the performance of some short flues under steady-state conditions Thulman, Robert D.; Shenkle, William H. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mechanical Engineering, 1951.; Bibliography: leaf 63.

The design of a combination room heater and hair dryer

Mon, 01 Jan 1951 00:00:00 GMT

The design of a combination room heater and hair dryer Semple, Eleanor L. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mechanical Engineering, 1951.; Bibliography: leaf 23.

Tensile testing of welds

Mon, 01 Jan 1951 00:00:00 GMT

Tensile testing of welds Casey, Walter Edward.; Terrenzio, Antonio. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Business and Engineering Administration, 1951.; Bibliography: leaf 20.

The terminal facilities of the port of Cleveland

Sat, 01 Jan 1927 00:00:00 GMT

The terminal facilities of the port of Cleveland Steinbrenner, Henry George. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Naval Architecture and Marine Engineering, 1927.

Models of common errors in a Tetris session

Mon, 01 Jan 1990 00:00:00 GMT

Models of common errors in a Tetris session Chang, Alice Ai-Yuan. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1990.; Includes bibliographical references (leaf 71).

History of the MIT Servomechanisms Laboratory and its implications for MIT's relations with government and industry

Fri, 01 Jan 1988 00:00:00 GMT

History of the MIT Servomechanisms Laboratory and its implications for MIT's relations with government and industry Paik, Kyoung Soo. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Humanities, 1988.; Includes bibliographical references.

The effects of changing enrichment supply conditions on world nuclear fuel trade patterns

Tue, 01 Jan 1980 00:00:00 GMT

The effects of changing enrichment supply conditions on world nuclear fuel trade patterns Hammond, Gerald Ellsworth. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1980.; Bibliography: leaf 49.

Security of nuclear fuel supplies to Western Europe

Mon, 01 Jan 1979 00:00:00 GMT

Security of nuclear fuel supplies to Western Europe Swartz, Gordon Spencer. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1979.; Bibliography: leaf 66.

Force-sensing foot design and control for reflexive balance control of biped robots

Tue, 01 Jan 2019 00:00:00 GMT

Force-sensing foot design and control for reflexive balance control of biped robots Whalen, Mallory(Mallory M.) In this work a force-sensing foot was designed and verified through balancing an inverted pendulum on an inclined plane. Its design, development, and verification are motivated by the stability needs of external robotic legs attached to workers that can help carry heavy personal protective equipment. The foot uses four load cells to sense changes in the normal force applied to the foot, thus being able to sense the angle of the ground. Verification testing shows that the system can be balanced, without an Inertial Measurement Unit, using only the load cells. In addition, a lightweight system of external robotics legs for use in human testing of quadrupedal gaits is designed. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, June, 2019; Cataloged from PDF of thesis. "The Table of Contents does not accurately represent the page numbering"--Disclaimer page.; Includes bibliographical references (page 29).

Characterizing the mechanical properties of rapid liquid printed silicone for use in prosthetic liners

Tue, 01 Jan 2019 00:00:00 GMT

Characterizing the mechanical properties of rapid liquid printed silicone for use in prosthetic liners Phillips, Elaine,S.B.(Elaine M.)Massachusetts Institute of Technology. Prosthetic socket liners have previously been commercially available only in set size increments. The Self Assembly Lab's new Rapid Liquid 3D printing will allow custom-fit flexible socket liners to be printed with medical-grade silicone, however the material characteristics of the silicone in this deposition pattern are not well understood. Under loaded conditions in a prosthetic socket, this uncertainty leads to suboptimal performance and comfort. The goal of this thesis project is to characterize the 3D printed soft silicone, which can then be used to 3D print custom-fit silicone socket liners that generate a custom pressure map on each residual limb. Samples of hyperelastic silicone were gathered from representative liners, their stress stretch curves were measured, and various hyperelastic models were fit to the data. The Ogden model was determined to yield the best fit for each specimen. These hyperelastic model parameters can be used to enable more accurate modeling and design of custom socket liners. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2019; Cataloged from PDF of thesis. "The Table of Contents does not accurately represent the page numbering"--Disclaimer page.; Includes bibliographical references (page 14).

Evaluating the effectiveness of green earth winterizer"̳ in breaching ice dams

Wed, 01 Jan 2020 00:00:00 GMT

Evaluating the effectiveness of green earth winterizer"̳ in breaching ice dams Guillaume, Mitchell L. Ice dams are a common and destructive problem faced by property owners in climates that experience winter weather. Floe is a startup developing a novel solution to prevent water damage caused by ice dams. The central concept of their product is to use a liquid deicing chemical to cut channels in ice at the roof's edge, allowing water to escape before it can enter the building. Before the product can be brought to market, its efficacy must be proven. To do so, it is necessary to be able to determine if an ice dam has been successfully breached by the deicing fluid without any manual inspection or intervention. To evaluate the merits of different measurement methods, a section of roof is constructed and placed in a cold chamber. A simulated ice dam is formed, and deicing fluid is dispensed. The roof's runoff is collected, and its pH and conductivity are recorded. The mechanics of breaching ice dams are also documented qualitatively. Though pH is a useful indicator of the runoff's concentration of deicing fluid, it is a more sensitive measurement and conductivity may be more reliable. The concentration of deicing fluid in the runoff increases as the ice dam is cut by the deicer. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis. ""̳" in title on title page appears as superscript TM.; Includes bibliographical references (page 16).

A private art gallery in Southern California

Sat, 01 Jan 1910 00:00:00 GMT

A private art gallery in Southern California Johnson, Reginald Davis,1882- Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1910.

Manufacturing urethane and latex molds for plaster casting

Tue, 01 Jan 2019 00:00:00 GMT

Manufacturing urethane and latex molds for plaster casting Olsen, Marianne E. This thesis compares nonindustrial, hobbyist materials and techniques for manufacturing multi-use molds for casting dozens of consistent and cost-effective complex objects out of plaster; in this case, skulls. Urethane, a pourable mold material, and latex, a spreadable mold material, were used to create molds and identify process issues. Plaster test casts were manufactured to identify defects; these defects were evaluated for their impact on the desired purpose and mitigation strategies were proposed. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2019; Cataloged from student-submitted PDF of thesis.; Includes bibliographical references (page 35).

An investigation of the saccharification of wheat mashes by fish amylases

Tue, 01 Jan 1952 00:00:00 GMT

An investigation of the saccharification of wheat mashes by fish amylases Brody, Herbert D.,1931- Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Food Technology, 1952.; Includes bibliographical references (leaves 22-23).

NIR silicon photodetector enhancement using photonic crystal cavity resonators

Tue, 01 Jan 2019 00:00:00 GMT

NIR silicon photodetector enhancement using photonic crystal cavity resonators Al Johani, Ebrahim Dakhil. The growing demand for efficient infrared sensors for light ranging, thermal-cameras, and soon, free-space optical communications has yet to be answered. In this study, we use polycrystalline silicon in conjunction with a photonic crystal cavity (PhCC) to enhance light absorption for efficient sensing. We present a cost-effective alternative to the current III-V detectors. By adding a 2D-PhC resonator layer, surface-illuminated light can be confined within a 10 micron region with great intensity, leading to a higher effective path-length and improved detector responsivity. More than 1000 variants of this detector are designed and implemented in a 65nm CMOS process. Using a nearest neighbor method, we find the optimized designs. We validate experimental findings by simulating mode behavior of the PhCC structures using FDTD models. In addition, a numerical study on cavity parameter optimization for achieving high Q-factors and extinction ratios specifically for surface-illumination is presented. We report polysilicon PhCC-enhanced sensors with Q-factors of 6500 resulting in responsivities at 1300nm up to 0.13mA/W -a 25x improvement over non-resonant surface-illuminated Silicon detectors. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2019; Cataloged from PDF of thesis. "The Table of Contents does not accurately represent the page numbering"--Disclaimer page.; Includes bibliographical references (pages 45-47).

Analysis of slurry composition for the direct ink writing of mayenite electride for use in thermionic cathodes

Tue, 01 Jan 2019 00:00:00 GMT

Analysis of slurry composition for the direct ink writing of mayenite electride for use in thermionic cathodes Han, Gina(Researcher in mechanical engineering)Massachusetts Institute of Technology. Thermionic cathodes, for use in electric propulsion thrusters, often utilize materials of low work function to decrease operating temperature and thus decrease power consumption. The ability to form these materials into complicated geometries allows for design of more efficient thermionic cathodes, such as multi-channel hollow cathodes. Mayenite electride, a calcium aluminate ceramic with a cage-like lattice structure that traps in electrons, has been identified as a low-work function ceramic that could be used for these thermionic cathodes. This thesis explores an additive manufacturing (AM) process for mayenite electride components, including the synthesis process for insulating mayenite and the development of an acetone-based slurry composition for direct ink writing (DIW). As the ink composition is critical to the success of any direct ink writing process, an in depth analysis was performed on mayenite slurries, which focused on different solvents, binders, and the dispersion of the ceramic particles. Water and acetone-based slurries were developed with mayenite, and printing tests showed that the printing mayenite with acetone as the solvent is viable, but greater dispersion of the mayenite powder within the slurry is necessary. In order to make quality components, the mayenite powder needs to be ground to a finer powder, the slurry needs to be mixed more thoroughly, or a dispersant must be added. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2019; Cataloged from PDF of thesis. "The Table of Contents does not accurately represent the page numbering"--Disclaimer page.; Includes bibliographical references (page 25).

Modeling flow characteristics of a low specific-speed centrifugal pump with different volute shapes

Tue, 01 Jan 2019 00:00:00 GMT

Modeling flow characteristics of a low specific-speed centrifugal pump with different volute shapes Wettermark, Susan Daly. A centrifugal pump is typically designed for a specific operating condition. The pump's shape and size are fine-tuned so that it can produce a specified output pressure and flow rate at the maximum possible efficiency. When a pump begins operating off of its design flow rate, its efficiency drops. Pumping systems often involve dynamic demands. They may have a fluctuating flow rate demand throughout the day, or the system may evolve and change size over time. In these cases, pumps with a single operating point are inefficient and insufficient. This thesis assesses the effects of changing a pump's volute casing geometry on the volute's internal flow characteristics. All analysis is performed on a low-specific-speed, radial flow centrifugal pump. 2D flow models from literature and CFD are analyzed and compared to experimental data. With properly-chosen solution methods, a 2D CFD simulation is found to match well with experimental results. Efficiency estimates and life-cycle cost changes due to changing flow characteristics in the variable volute system are presented. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, June, 2019; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 39).

Flow test of a Bristol sleeve-valve engine cylinder

Mon, 01 Jan 1951 00:00:00 GMT

Flow test of a Bristol sleeve-valve engine cylinder Thomson, Mark Riley. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mechanical Engineering, 1951.; Bibliography: leaves 32-33.

Preliminary report on the quadratic Zeeman effect

Mon, 01 Jan 1951 00:00:00 GMT

Preliminary report on the quadratic Zeeman effect Erber, Thomas,1930- Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Physics, 1951.

Design of an apparatus to measure the gravitational constant

Mon, 01 Jan 1951 00:00:00 GMT

Design of an apparatus to measure the gravitational constant Duane, Bernard H. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Physics, 1951.

Electron density and average electron energy in the D.C. glow discharge

Mon, 01 Jan 1951 00:00:00 GMT

Electron density and average electron energy in the D.C. glow discharge Dreicer, Harry. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Physics, 1951.; Bibliography: leaf 44.

Analysis of aerosol coagulation in a sound field

Mon, 01 Jan 1951 00:00:00 GMT

Analysis of aerosol coagulation in a sound field Cole, Earl Gage. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Physics, 1951.; Bibliography: leaf 24.

Some improvements in the automatic recording spectrophotometer of the color measurements laboratory

Mon, 01 Jan 1951 00:00:00 GMT

Some improvements in the automatic recording spectrophotometer of the color measurements laboratory Champeny, John C.(John Charles) Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1951.; Bibliography: leaves 31-32.

Application of narrow light beams to the photoelastic study of tempered glass

Mon, 01 Jan 1951 00:00:00 GMT

Application of narrow light beams to the photoelastic study of tempered glass Resnick, Ira L.; Casella, Russell C. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Physics, 1951.

The microwave absorption spectrum of deutero formaldehyde

Mon, 01 Jan 1951 00:00:00 GMT

The microwave absorption spectrum of deutero formaldehyde Sieck, Peter Wieboldt.; Blumberg, Leroy Norman. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Physics, 1951.; Bibliography: leaves 44-45.

Initial velocity grid current in acorn tube type 954

Mon, 01 Jan 1951 00:00:00 GMT

Initial velocity grid current in acorn tube type 954 Benson, Robert C. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Physics, 1951.; Bibliography: leaf [17].

The extension of the linear bandwidth of the Granlund frequency detector

Mon, 01 Jan 1951 00:00:00 GMT

The extension of the linear bandwidth of the Granlund frequency detector Baker, Charles Lewis. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Physics, 1951.; Bibliography: leaves 35-36.

The design of a machine to powder milk

Sun, 01 Jan 1922 00:00:00 GMT

The design of a machine to powder milk Young, William Hoyt.; Sutherland, Kenneth Reynold. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1922

Studying methods of facing mail

Wed, 01 Jan 1958 00:00:00 GMT

Studying methods of facing mail Seigle, Louis Buck,1936- Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1958.; Includes bibliographical references (leaf 31).

An experimental study of heat transfer film coefficients for turbulent flow of water at the inlet of a horizontal tube

Wed, 01 Jan 1958 00:00:00 GMT

An experimental study of heat transfer film coefficients for turbulent flow of water at the inlet of a horizontal tube Schnitzer, Herbert Allen. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1958.; Vita.; Includes bibliographical references.

Jet losses in partial admission turbine

Wed, 01 Jan 1958 00:00:00 GMT

Jet losses in partial admission turbine Schmidt, Robert Max. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1958.; Includes bibliographical references (leaf 31).

The manufacture of a spring driven man's face shaver

Wed, 01 Jan 1958 00:00:00 GMT

The manufacture of a spring driven man's face shaver Skala, Paul John.; Scharer, Hans Rudolph. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1958.; Includes bibliographical references.

A probe to measure stagnation pressure, static pressure, yaw and pitch angle

Wed, 01 Jan 1958 00:00:00 GMT

A probe to measure stagnation pressure, static pressure, yaw and pitch angle Samela, Daniel A.(Daniel Aloysius) Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1958.

Analysis of a six bar intermittent motion linkage

Wed, 01 Jan 1958 00:00:00 GMT

Analysis of a six bar intermittent motion linkage Rosenthal, Richard Alan. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1958.; Includes bibliographical references (leaf 41).

Investigation of exit plan conditions for a 90 ̊bend in circular pipe as a function of inlet mach number

Wed, 01 Jan 1958 00:00:00 GMT

Investigation of exit plan conditions for a 90 ̊bend in circular pipe as a function of inlet mach number Rodolitz, Allan J.(Allan Jay) Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1958.; Includes bibliographical references (leaves [18]).

The testing of a static temperature measuring probe in high velocity air streams

Tue, 01 Jan 1952 00:00:00 GMT

The testing of a static temperature measuring probe in high velocity air streams Coakley, Donald William. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mechanical Engineering, 1952.; Bibliography: leaf 22.

The grinding of leather and other non-metallic materials

Tue, 01 Jan 1952 00:00:00 GMT

The grinding of leather and other non-metallic materials Burditt, Robert B. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mechanical Engineering, 1952.; Bibliography: leaves 24-25.

Mechanical properties and grinding characteristics of titanium

Tue, 01 Jan 1952 00:00:00 GMT

Mechanical properties and grinding characteristics of titanium Buckland, Lawrence F. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mechanical Engineering, 1952.; Bibliography: leaf 36.

Development of an improved two stage centrifugal blower for the electrolux vacuum cleaner

Tue, 01 Jan 1952 00:00:00 GMT

Development of an improved two stage centrifugal blower for the electrolux vacuum cleaner Brownell, James Fulton.; Chen, William Sang-One. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mechanical Engineering, 1952.; Bibliography: leaf 76.

Instrumentation for the performance testing of miniature two stroke engines

Tue, 01 Jan 1952 00:00:00 GMT

Instrumentation for the performance testing of miniature two stroke engines Borden, Roger Richmond.; Smith, Everett D. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mechanical Engineering, 1952.; Bibliography: leaf 41.

Evaporation from free water surfaces

Wed, 01 Jan 1958 00:00:00 GMT

Evaporation from free water surfaces Freese, Lee B. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Civil and Sanitary Engineering, 1958.; Includes bibliographical references (leaves [37]-[39]).

Study of traffic operations on Massachusetts route 128

Wed, 01 Jan 1958 00:00:00 GMT

Study of traffic operations on Massachusetts route 128 Fisher, Fred.; Fleischer, Gustave. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Civil and Sanitary Engineering, 1958.; Includes bibliographical references (leaf 33).

Design of a short concrete shell

Wed, 01 Jan 1958 00:00:00 GMT

Design of a short concrete shell Finn, Richard Allan. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Civil and Sanitary Engineering, 1958.

Separating the effects of water activity and humectant on the growth of staphylococcus aureus

Thu, 01 Jan 1976 00:00:00 GMT

Separating the effects of water activity and humectant on the growth of staphylococcus aureus Hirasuna, Thomas Jyun. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1976.; Includes bibliographical references (leaves 46-47).

The multidimensional Wegstein method and the comparison of convergence procedures

Thu, 01 Jan 1976 00:00:00 GMT

The multidimensional Wegstein method and the comparison of convergence procedures Frank, Harry Charles. Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1976; Includes bibliographical references (leaf 95).

The effect of liquid characteristics upon the breakup of a liquid jet

Thu, 01 Jan 1976 00:00:00 GMT

The effect of liquid characteristics upon the breakup of a liquid jet Chmura, Richard Anthony. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1976.; Includes bibliographical references (leaves 122-123).

A dynamic model for continuous adiabatic drying

Thu, 01 Jan 1976 00:00:00 GMT

A dynamic model for continuous adiabatic drying Campanella, David Anthony. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1976.; Includes bibliographical references (leaf 43).

Evaluation of reactor catalyzed secondary reactions in the captive sample pyrolysis reactor

Thu, 01 Jan 1976 00:00:00 GMT

Evaluation of reactor catalyzed secondary reactions in the captive sample pyrolysis reactor Bennet, Kevin E.(Kevin Elliott) Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1976.; Includes bibliographical references (leaves 58-59).

The effect of heat-treatment upon the physical properties of wrought iron

Sat, 01 Jan 1916 00:00:00 GMT

The effect of heat-treatment upon the physical properties of wrought iron Loo, P. Y.; Tai, S. T. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1916.

The development and characteristics of fans

Sun, 01 Jan 1922 00:00:00 GMT

The development and characteristics of fans Southam, Albert Edward.; Loss, Isidor. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1922; Includes bibliographical references (leaves 86-87).

Preferred orientations in rolled metals, construction of pole figure by back-reflection method

Fri, 01 Jan 1943 00:00:00 GMT

Preferred orientations in rolled metals, construction of pole figure by back-reflection method Siddhi Savetsila. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Metallurgy, 1943.; Includes bibliographical references (leaf 25).

Ferrotungsten: the direct reduction of scheelite by ferrosilicon

Fri, 01 Jan 1943 00:00:00 GMT

Ferrotungsten: the direct reduction of scheelite by ferrosilicon Pei, Yu Kun. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Metallurgy, 1943.; Includes bibliographical references (leaves 25-26).

The production metallurgy of beryllium salts

Fri, 01 Jan 1943 00:00:00 GMT

The production metallurgy of beryllium salts Greenewald, Herbert. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Metallurgy, 1943.; Includes bibliographical references (leaves 45-46).

The solubility of hydrogen in alloys of aluminum and copper

Fri, 01 Jan 1943 00:00:00 GMT

The solubility of hydrogen in alloys of aluminum and copper Feuerring, Ralph.; Safoglu, Rejep. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Metallurgy, 1943.; Includes bibliographical references (leaf 29).

The design of a desmodromic valve mechanism for an internal combustion engine

Sun, 01 Jan 1961 00:00:00 GMT

The design of a desmodromic valve mechanism for an internal combustion engine Oberhauser, Charles John. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1961.; Includes bibliographical references.

Thermal conductivity of metals and non metals

Sun, 01 Jan 1961 00:00:00 GMT

Thermal conductivity of metals and non metals Gujral, Deepa Mohan. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1961.; Includes bibliographical references (leaf [19]).

Investigation of the isotropic points, in a circular ring subjected to concentrated diametral loads, in a section parallel to the loading plane

Sun, 01 Jan 1961 00:00:00 GMT

Investigation of the isotropic points, in a circular ring subjected to concentrated diametral loads, in a section parallel to the loading plane Bloom, George H. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1961.; Includes bibliographical references (leaf 29).

The thermite welding of cast iron

Wed, 01 Jan 1958 00:00:00 GMT

The thermite welding of cast iron French, David N. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Metallurgy, 1958.

Physical property constant estimation of coal liquids

Sun, 01 Jan 1978 00:00:00 GMT

Physical property constant estimation of coal liquids Tsang, Mun C. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1978.; Includes bibliographical references (leaves 105-106).

A least square procedure for solving complex integral equations of a single real variable by polynomial approximation

Sun, 01 Jan 1956 00:00:00 GMT

A least square procedure for solving complex integral equations of a single real variable by polynomial approximation Wenker, Jerome,1934- Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mathematics, 1956.; Bibliography: leaf [37].

Programing for a digital computer

Sun, 01 Jan 1956 00:00:00 GMT

Programing for a digital computer Rosene, A. Frederick. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mathematics, 1956.; Bibliography: leaf 29.

Approximation and computation of fourier transforms

Sun, 01 Jan 1956 00:00:00 GMT

Approximation and computation of fourier transforms Romberg, Bernhard Walter,1934- Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mathematics, 1956.; Bibliography: leaf 37.

The use of divided differences in error estmates

Sun, 01 Jan 1956 00:00:00 GMT

The use of divided differences in error estmates Hanson, D. L.(David Lee),1935- Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mathematics, 1956.; Bibliography: leaf 30.

Some aspects of the early history of mathematics

Sun, 01 Jan 1956 00:00:00 GMT

Some aspects of the early history of mathematics Gorenstein, Judith. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mathematics, 1956.; Bibliography: leaves 29-30.

The application of a least square procedure to the solution of a homogeneous linear integral equation problem by polynomial approximation

Sun, 01 Jan 1956 00:00:00 GMT

The application of a least square procedure to the solution of a homogeneous linear integral equation problem by polynomial approximation Creese, Thomas M. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mathematics, 1956.; Bibliography: leaf 21.

A digital computer program for the computation of commutation tables

Sun, 01 Jan 1956 00:00:00 GMT

A digital computer program for the computation of commutation tables Binner, Doretta Ann. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mathematics, 1956.; Bibliography: leaf [45].

Statistical satructure of consonant clusters

Sun, 01 Jan 1956 00:00:00 GMT

Statistical satructure of consonant clusters Bell, Alan Edward. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mathematics, 1956.; Bibliography: leaves 47-48.

The theory of adiabatic invariants in statistical mechanics

Sun, 01 Jan 1956 00:00:00 GMT

The theory of adiabatic invariants in statistical mechanics Barakat, Richard Gordon. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mathematics, 1956.; Bibliography: leaf [47].

Information content as a determinant of average reaction times to pure tones a preliminary investigation

Sun, 01 Jan 1956 00:00:00 GMT

Information content as a determinant of average reaction times to pure tones a preliminary investigation Albert, Arthur E. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mathematics, 1956.; Bibliography: leaf 22.

A relaxation method for linear programming

Sun, 01 Jan 1956 00:00:00 GMT

A relaxation method for linear programming Abrahams, Paul W. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mathematics, 1956.; Bibliography: leaf 29.

The selection and testing of a tension member for a height-variable portable hospital bed

Fri, 01 Jan 1993 00:00:00 GMT

The selection and testing of a tension member for a height-variable portable hospital bed Watanabe, Gwendolyn Ann. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1993.; Includes bibliographical references (leaf 22).

Niobium sulfide : a study of the effects of pressure and substrate orientation on kinetics and structure

Thu, 01 Jan 1987 00:00:00 GMT

Niobium sulfide : a study of the effects of pressure and substrate orientation on kinetics and structure Sedlacek, Louise Mae. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1987.; Bibliography: leaf 36.

Quantitative phonetic and frequency domain characterization of vocal blend for sung vowels

Wed, 01 Jan 2020 00:00:00 GMT

Quantitative phonetic and frequency domain characterization of vocal blend for sung vowels Lu. Jennifer,S.B.Massachusetts Institute of Technology. Choral performance focuses on achieving the illusion of many voices singing as one smooth, cohesive tone, known as vocal blending. Choral pedagogy includes instructions on how to blend, but there is little information in the literature on how these qualitative instructions result in quantitative changes in the frequency domain. Voice samples of two altos with choral backgrounds were collected. They sung vowels [i], [u], [el, [o], and [[alpha]] together on a D4 (293 Hz), transitioning from unblended to blended tones, and data were analyzed using frequency domain techniques. For a musical pitch, the presence of higher harmonics amplifies dissonant intervals, which are undesirable in a blended choral sound. Choral singers are taught to ''darken" their tones (reduce the amplitude of higher harmonics) and modify their vowels by dropping their jaws and rounding their lips to achieve blend. The summed Fourier amplitudes for higher harmonics as a fraction of the sum of the fundamental frequency and second harmonic decreases by (82 ± 8)% for vowels [i] and [u], and (62 ± 12)% for vowels [e], [o], and [a] after transitioning to a blended sound. It can be concluded that significant overtone suppression occurs after blending. Vowel formants, the resonance frequencies of cavities in the vocal tract, amplify higher harmonics close in frequency to a given formant frequency. Across all vowels, the 2nd, 3rd, and 4th formant drop 1-3 harmonics between the unblended and blended time states, indicating that vowel modification reduces the intensity of dissonant intervals in higher harmonics by amplifying lower, more consonant harmonics. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis. Page 44 blank.; Includes bibliographical references (page 43).

Using publicly available financial data to measure production depth in the automobile industry

Wed, 01 Jan 2020 00:00:00 GMT

Using publicly available financial data to measure production depth in the automobile industry Legg, Cole C. Often companies must make the decision whether or not to manufacture a part on their own or to outsource the manufacturing of that part to a supplier. The results of these "make-or-buy" decisions have impacts on that company's manufacturing competencies and strategies moving forward [1]. They also compound over time to define that company's production depth. A company's production depth is defined as the ratio of value-adding content that a company creates itself [2]. While the impact of "make-or-buy" decisions have clear implications on a company's long-term strategies, the relationship between a company's production depth and its profitability has not yet been studied as there is not a defined way to measure production depth from a company's publicly available financial data. This study examines two different methods of estimating production depth using publicly available financial data.; The first method uses the ratio of raw and in-progress materials versus finished goods in a company's inventories to represent the company's production depth. The second method for estimating production depth is the ratio of the difference between the company's manufacturing cost and total trade purchases to its total cost of manufacturing. This study used the first method to evaluate different automotive companies' production depth in 2018. This study also examines BMW's production depth using both methods. The first method of measuring production depth is advantageous because all public automotive companies published the data on their inventories necessary to make the calculation. The second method is advantageous because it takes into account costs with manufacturing outside of just material costs.; While there were no statistically significant relationships found between this study's production depth estimates and profitability, applying these two methods two automotive companies allowed us to gain insight into estimating production depth using publicly available financial data. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 14).

Design of a load-lock system for the lyophilization of unit-dose pharmaceuticals in a continuous manufacturing machine

Wed, 01 Jan 2020 00:00:00 GMT

Design of a load-lock system for the lyophilization of unit-dose pharmaceuticals in a continuous manufacturing machine Le, Serena. Lyophilization, or freeze drying, of unit-dose pharmaceuticals eliminates the need to preserve quality through regulated temperature storage during transport. Typical lyophilization is performed through batch processing, but implementing continuous manufacturing instead can lead to improved process control, higher quality product, and increased flexibility. Lyophilization involves four processing chambers at specific pressures and transferring vials between the chambers requires a load lock system. Load lock systems, commonly used in the semiconductor industry, act as a transfer chamber in order to reduce pump-down and venting time of its adjacent processing chambers. This thesis documents the research and design of a load lock system for a continuous manufacturing lyophilization machine. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 65-66).

Manifold and base casting of Lunenburg Foundry Atlantic Marine Engine

Wed, 01 Jan 2020 00:00:00 GMT

Manifold and base casting of Lunenburg Foundry Atlantic Marine Engine Kirby, Chiaki(Chiaki Louise) Previous work started by mechanical engineering students in the spring of 2016 established a basis for applying modern machining and modeling techniques to the fabrication of century old sand cast designs, specifically a Lunenburg Foundry Atlantic Engine. This project was continued by mechanical engineering students in the spring of 2019. From there, this groundwork was used to fabricate one of the remaining parts of the engine, the lower base. Due to COVID-19 pandemic and MIT campus shut down, this thesis project was virtualized. From this, casting simulation software (Visual Cast) used to simulate the casting of another engine part, the manifold, with a variety of geometries and process conditions. The simulations were completed to predict the casting quality of the part if physically cast. Additionally, the next steps for completion of the engine are outlined. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 41).

Optical detection of finger pressure through utilization of nailbed color changes

Wed, 01 Jan 2020 00:00:00 GMT

Optical detection of finger pressure through utilization of nailbed color changes Henshaw, Katie(Katherine A.) This thesis presents the theory and design of a sensor that detects a when a finger is pressed by visually examining a user's fingernail coloration. Unlike other finger-based controllers that primarily depend on covering the finger pad, this method of sensing allows for accurate measurements without impairing a user's tactile sense. First the color change of a fingernail is examined based on the underlying biological mechanisms of the finger. Then the hue, saturation, and value (HSV) coordinates of videos of the fingernails are analyzed in three different locations; the entire image, a segment of the rear of the fingernail, and a segment of the tip of the fingernail. The front of the fingernail, where a white band develops when pressure is applied to the finger, proved to have statistically significant increases in saturation and value for all test subjects. With these results a simple sensor was designed and tested that accurately sensed finger presses, however with a significant time lag. Finally, the mechanical design of such a sensor was proposed, leaving room for further study and development. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 14-15).

Analysis of the materials and energy cost to manufacture graphene by roll-based chemical vapor deposition

Wed, 01 Jan 2020 00:00:00 GMT

Analysis of the materials and energy cost to manufacture graphene by roll-based chemical vapor deposition Hanlon, Henry M.(Henry M. S.) A single layer of graphite, called graphene, has immense promise as a material. Despite being essentially two-dimensional, graphene is stronger than steel in tension. The material has extremely high electron mobilities even at room temperature. It can be used as a filter and has the added benefit of being transparent. Despite this impressive resume, graphene remains the topic of scientific papers and not dinner tables. One of the reasons for this is the difficulty and associated costs of mass manufacture. This paper proposes parameters for the production of graphene via roll-to-roll chemical vapor deposition, through the lens of eight case study experiments. Once the parameters are understood, the paper seeks to provide variable cost estimates, focused mostly on the cost of materials and energy required for this process. The analysis reveals that cost of production depends heavily on the substrate -- commonly copper (typically $40 m⁻²) -- and specifically the thickness and quality or purity of the metal. Considering process parameters based on literature reports of roll-based graphene synthesis, the costs of energy and gasses are significantly less, approximately $1.74 and $1.11 per m⁻², respectively. The equipment based on currently available prices is approximately $ 1 m⁻². Future experiments or for-profit production should explore different substrates, the recycling of copper substrates, optimization of the gas flow rates and furnace insulation, or multi-side production of graphene. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 18-20).

Analyzing the feasibility of lithium-ion batteries to reduce carbon dioxide emissions in Maritime shipping

Wed, 01 Jan 2020 00:00:00 GMT

Analyzing the feasibility of lithium-ion batteries to reduce carbon dioxide emissions in Maritime shipping Hartnett, Luke(Luke S.) The International Maritime Organization aims to reduce CO2 emissions in the shipping industry by 50% by 2050. One of the methods for meeting this goal is to electrify ships with lithium-ion batteries. A 14-ship sample was analyzed to determine the feasibility of installing lithium-ion batteries onto modern-day vessels. The two feasibility constraints that guided this discussion were mass and volume of the necessary battery system. Results show that the mass of the battery pack was well within the current mass of engine rooms, but the volume required was often too high. In order to compensate for this, an increase in the estimate of energy density improved the number of trips made possible by lithium-ion batteries. When coupled with increases in depth of discharge and the volume available for the system in the engine room, 11 out of 14 vessels could complete at least one trip with one charge of the battery. This corresponded to about 48% of the total miles travelled by all 14 ships. Hybrid vessels could be deployed to test out the technology, but eventually moving to lithium-ion battery technology could come close to reducing emissions by 50% under the right parameters. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 31).

Relaxation behavior of dense suspensions

Wed, 01 Jan 2020 00:00:00 GMT

Relaxation behavior of dense suspensions Griese, Andrew Herman. Dense suspensions of solid particles in Newtonian fluids exhibit a variety of non-Newtonian behaviors depending on the shear stress applied to the suspension and the particle mass fraction ([mathematical symbol]m). Suspensions at sufficiently high fm shear-thicken dramatically and eventually shear jam, showing behaviors typified by solids. But, little is known about how dense suspensions relax out of this stressed rheological state. To understand the relaxation behavior of a cornstarch/water dense suspension, samples are prepared at different fm, in the range that shows dramatic shear thickening, between 54.5% and 58.5% cornstarch. Each sample is formed into drops and kept in the stressed state through dynamic shearing using a B&K permanent magnet shaker, then allowed to relax. We show that dense suspensions relax with two distinct timescales. A short timescale that is independent of [mathematical symbol]m, denoting the settling of the drop onto the flat surface, and a longer timescale that is governed by the viscosity of the dense suspension and increases as [mathematical symbol]m increases above 55.75%. Our work provides an understanding of how a dense suspension relaxes out of a shear-thickened state. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 16-17).

Effect of ball impact location and temperature on softball bat handle vibration

Wed, 01 Jan 2020 00:00:00 GMT

Effect of ball impact location and temperature on softball bat handle vibration Goetz, Devon K. The bat-ball collision is a crucial part of softball, and minimizing excessive vibrations in the bat after impact makes batting more comfortable for the hitter and optimizes the transfer of momentum between the bat and ball. To better understand this collision, the magnitude of bat handle vibrations as a function of ball impact location was measured across three bat brands and at three different temperatures. The bat barrel was struck with an impact hammer and an accelerometer placed near the handle of the bat collected the output data. Following an experiment conducted at room temperature, the bats were placed in extreme heat and cold and the same experiment was performed. The bats resonate in two main frequency ranges associated with the first bending mode and a hoop mode. The bending mode frequency was consistent across all impact locations, but did vary slightly between bat types. The hoop mode frequency varied depending on location. Hitting a ball with the bat's sweet spot, where a node of the bending mode is located, minimizes the magnitude of vibrations at the handle, primarily by eliminating the first bending mode. In general, cold temperatures tend to inhibit the bat's ability to minimize vibrational output, leading to more energy being transferred to the batter's hands. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 34).

Review of energy harvesting methods for twin screw extruders

Wed, 01 Jan 2020 00:00:00 GMT

Review of energy harvesting methods for twin screw extruders Lenhard, Allison N. Energy harvesting is the process of accumulating and storing energy from residual sources for use in powering electronic devices. Low-power energy harvesting technologies typically utilize either mechanical, thermal, radiation, flow-based, or bio-chemical energy sources. Research in low-power energy harvesting technologies is motivated by an increased interest in the Internet of Things and the need to create isolated electronic systems, such as wireless sensor networks for system monitoring. Twin screw extruders are a type of extrusion processing machinery and could benefit from a condition monitoring system. Implementing a condition monitoring system for a twin screw extruder can prevent wasting materials, producing unusable products, and working extensively on machine maintenance. However, it becomes difficult to integrate a condition monitoring system into the machinery because of the lack of accessibility. Condition monitoring would have to occur in the process section of the twin screw extruder, but the nature of the process section makes it difficult to implement a traditionally wired and powered condition monitoring system. A condition monitoring system powered by energy harvesting techniques would be ideal for a twin screw extruder. The shaft mechanical vibrations, high temperature thermal dissipation, and polymer fluid dynamics present in a twin screw extruder can potentially be used in an energy harvesting system. After a literature review, mechanical vibrations and temperature gradients were regarded as the best potential energy harvesting drivers. Based on preliminary analysis of the system, vibrational energy harvesting is predicted to produce between 3.35-16.75 mW of power, while thermally driven energy harvesting is expected to produce between 8-15 mW of power. The estimated power output would be significant enough to power a low-power consumption strain sensor and has the potential to power other sensors as well. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 44-48).

TeachBot : an automated, hands-on apprenticeship program

Wed, 01 Jan 2020 00:00:00 GMT

TeachBot : an automated, hands-on apprenticeship program Go, Albert(Albert P.) There are a plethora of medium and small-sized manufacturing companies that do not rely completely on autonomous systems. As a result, it is more economical to use a mixture of human labor and manufacturing robots; however, with the thousands of people who apply for these jobs, many do not have the experience to work along-side robots or understand how robots works. The research described by this thesis introduces a solution to this problem through TeachBot, an automated, hands-on apprenticeship program. TeachBot seeks to empower manufacturing workers with the skills necessary to work collaboratively with robots in the manufacturing industry. Through the use of ROS, the program teaches key topics in robotics such as encoders, kinematics, feedback, and programming through multiple interactive modules. TeachBot is setup with three main components: a JSON file of instructions, a JavaScript file, and a python file. The JavaScript file parses the instructions and sends commands to the python script. The python script then sends these commands to the robot. This process allows TeachBot to be modular and universal such that it can be modified easily and applied to any robot. This research focuses on implementing TeachBot onto the Sawyer Robot and the possible extension to the Universal Robot 5e. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 55-56).

An exploration and review of ethics instruction methods for undergraduate engineering students and an examination of the MIT Mechanical Engineering Department's current practices in teaching ethics

Wed, 01 Jan 2020 00:00:00 GMT

An exploration and review of ethics instruction methods for undergraduate engineering students and an examination of the MIT Mechanical Engineering Department's current practices in teaching ethics Gavin, Kiera(Kiera A.) All accredited undergraduate engineering programs are required to teach ethics based on the ABET mandated Student Outcomes. How programs choose to do this is highly variable, but curriculum typically falls into one of three categories: the case method, theory-based method, and professional codes method; despite their prevalence in contemporary teaching, each of these methods has its flaws [1]. One school of thought argues that teaching the ethical thought process as a parallel to the engineering design process is the most effective way to communicate ethics to engineering students [2-5]. In order to understand what mechanical engineering students at MIT take away from their ethics education, a survey was sent to all students who had completed the most recent semester of one of the MIT Mechanical Engineering capstone courses. 52% of students responded, revealing a large variation in understanding of ethics and engagement with the ethics components of the course. Recommendations are made for changes to the ethics components of the course curriculum, aiming to improve the deficiencies highlighted in the survey and approach ethics instruction through the design process lens. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 28).

Interrogating the lungs through wearable fabric electronics

Wed, 01 Jan 2020 00:00:00 GMT

Interrogating the lungs through wearable fabric electronics Fung, Johnny(Johnny Z.) Lung disease such as pneumonia is one of the leading causes of mortality throughout the world. Currently, many screening techniques performed on the lungs are too expensive, cumbersome, not continuous, and not easily understood without proper medical training. Furthermore, with the pandemic of Covid-19, the demand of screening patients in a non-invasive method has skyrocketed. Stethoscopes require training to understand the abnormalities when listening to the sounds the body makes, also known as auscultation. In this thesis, we sought to develop a lightweight, flexible, wearable fabric that can perform auscultation on the lungs. These fibers were created using the thermal drawing process that allows the fibers to perform various functions depending on the materials used for the draw. The initial solution used a conductive fiber created by injecting a liquid metal into a hollow fiber. This was deemed inadequate as the fiber generated a lot of noise and was only capable of detecting respiratory rates on a body with minimal movement. With minimal movement, this destroyed the purpose of having the fiber be mobile and flexible. The second solution utilized a nanostructured piezoelectric fiber to listen to the sounds the body makes. The piezoelectric fiber was successfully able to detect the sound of a heartbeat, but the lung sounds were overwhelmed due to the loudness of the heart. These sounds were measured with the fiber placed on the chest. For future studies, the fiber will be placed in various locations on the body to determine the optimal location for auscultation of the lungs. Furthermore, the shape of the fiber network will be optimized, creating an amplifying effect in the direction of interest. This will be an attempt to minimize the noise coming from the heart and focus more on the sounds the lung makes. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 17).

Stiffness prediction methods for additively manufactured lattice structures

Wed, 01 Jan 2020 00:00:00 GMT

Stiffness prediction methods for additively manufactured lattice structures Folinus, Charlotte Méry. Since the initial 300 pair release of the Futurecraft 4D in April 2017, adidas has scaled its 4D program to mass produce additively manufactured shoe midsoles. The 4D midsoles are constructed from lattice structures, and if there is variation in the manufacturing process, the structure's material and/or geometric properties may be altered. This means midsoles may have the same geometry but different material properties and thus different stiffnesses, and they may also have the same material properties but different overall stiffness due to geometric changes. The current quality control test is slow, expensive, and does not scale well. This thesis explores two potential techniques: using ultrasonic waves to determine the lattices' acoustic properties, and weighing them to determine their mass. Pulse-echo testing data for n = 8 samples shows a statistically significant (p = 0.0398 < 0.05) increase in response time due to sample stiffness. Stiffness scaled linearly with lattice mass for both physical and simulated lattices, and mass predicted lattice stiffness with a minimum accuracy of 90% across a range of simulated manufacturing conditions. An analytical framework parameterized around a bivariate normal distribution can determine accuracy of new test methods or from additional mass-stiffness data. Lastly, cost minimization is presented for a hybrid test protocol which combines mass testing with secondary testing for rejected samples. At specification limits of ±1[sigma], the hybrid test achieves 99% accuracy at 69.8% of the cost for the current test. Increasing the specification limit to ±2[sigma] reduces cost further, achieving 99% accuracy at 16.4% of the current cost. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 87-91).

Design of load-lock door for unit dose continuous lyophilization process for complex biologics

Wed, 01 Jan 2020 00:00:00 GMT

Design of load-lock door for unit dose continuous lyophilization process for complex biologics Flores, Ryan Maximiliano. The process of unit dose continuous lyophilization consists of moving vials containing unit doses of pharmaceutical product though a series of process chambers with varying pressures and temperatures. In order to move the vials between process chambers with varying pressures without disturbing the conditions within each respective chamber, a load lock is required. Although load locks are commonly used in the semiconductor industry, existing designs are not directly applicable to the unit dose continuous lyophilization process due to the unique geometric constraints on the system. This thesis document details the design of a load-lock door for the unit dose continuous lyophilization process. To meet the load-lock door functional requirements, a four-bar linkage load-lock door and a load-lock door with ground pivots offset from the sealing surface were designed. Because the driving performance parameters cannot be reliably modeled, the seal performance, particle generation, and seal adhesion of each design will be experimentally tested. The highest performing design will be chosen and improved based on the experimental results. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 61-62).

Student team decision-making processes and assessment criteria in early stage engineering design

Wed, 01 Jan 2020 00:00:00 GMT

Student team decision-making processes and assessment criteria in early stage engineering design Fang, Amy Q. Background: Lab meetings are observed at the beginning and the middle of a senior product design capstone course for mechanical engineering students. Purpose: This paper seeks to understand how social team decision-making processes and assessment criteria affect the quality and process of group coherence and communication for mechanical engineering students Design and Method: Audio and video meeting recordings with written transcripts, mid-term product milestone evaluations, and course materials are analyzed through qualitative observation and thematic analysis. Pivotal moments and key differences between teams and within the same teams over time are noted in relation to the ideation and decision-making process. Results: Emerging themes that affect decision-making are compared across teams and lab meetings, and influential teamwork dynamics and assessment criteria are qualitatively noted as well. Conclusions: Novice student designers are solution-oriented in prioritizing technical feasibility and product details in selecting product design ideas. Across teams, they vary in levels of acceptance of undefined key terms in navigating ill-defined design problems. In the context of design education, class materials and instructor feedback play an influential role in shaping team meetings, discussions, and assessment criteria. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 36).

Design of a stabilization method for cable suspended camera systems

Wed, 01 Jan 2020 00:00:00 GMT

Design of a stabilization method for cable suspended camera systems Arons, Nicolas(Nicolas H.) Scootah Hockey is a small sport with a yearly championship held in Simmons Hall at MIT. To help grow the sport, a cable suspended camera system called the SHKYCAM was designed to enable online streaming of matches. Due to unique features of the sport, the SHKYCAM encounters large disturbances during the normal course of play, resulting in shaky video footage and a poor streaming experience. In this thesis, a literature study of cable mounted camera systems was performed to understand current solutions used in camera stabilization during sporting events. Additionally, a controller was designed to be used with a flywheel to steady the system in response to a disturbance. In simulation, the controller reduced the settling time by four orders of magnitude, but was ultimately deemed infeasible to implement. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 19).

The design and fabrication of an autonomous hybrid VTOL aircraft

Wed, 01 Jan 2020 00:00:00 GMT

The design and fabrication of an autonomous hybrid VTOL aircraft Alshareef, Amro A. Low-cost Unmanned Aircraft Systems have proven to be extremely useful for tracking and mapping coherent atmospheric structures. These aircraft systems are often required to alternate between dynamic, non-uniform sampling and deterministic trajectories, which makes VTOL aircrafts especially suitable for these applications. Outlined is the process by which an autonomous VTOL aircraft weighing less than 10 kg and powered by a hybrid engine is designed and fabricated. The preliminary design of the aerodynamic shell is overviewed. Design requirements for the aircraft are then listed, followed by design and analysis of individual components and mechanisms within the structure in order to inform material selection. The fabrication process of the aircraft is then described, followed by the design and fabrication of a 4-axis CNC foam cutter needed to cut the aerodynamic surfaces of the aircraft out of EPP foam. Lastly, further work to be done on the CNC foam cutter and the Aircraft is listed. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 25).

Design architecture for dynamic low inertia multi DOF robotic manipulators

Wed, 01 Jan 2020 00:00:00 GMT

Design architecture for dynamic low inertia multi DOF robotic manipulators Massie, Mason(Massie R.) This thesis is intended as a background for robotic designers interested in creating low inertia, high bandwidth, multi DOF robotic arms and hands capable of proprioceptive force feedback from the world. This thesis briefly outlines the physics that govern the dynamics of robotic manipulators. It further covers various actuators and transmissions along with their dynamic and mechanical properties. Finally, this thesis covers overall robotic arm and hand architecture; where degrees of freedom can be placed and how actuators can be mounted and transmitted. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 60).

Model of reflectance of thermophotovoltaic cell and cold plate

Wed, 01 Jan 2020 00:00:00 GMT

Model of reflectance of thermophotovoltaic cell and cold plate Milde, Lucy(Lucy E.) The reflectivity of a gold-plated cold plate, and mounted multi-junction photovoltaic cells, is studied in the context of a thermal energy grid storage system. The emitter is modeled as a black body emitter. Improving the efficiency of the system requires high reflectance below the bandgap energy of the cells, and high absorption above the bandgap. The matrix transfer method is used to predict the total reflectance of the cell, and to study the effect of changing the thickness of the most significant layer. Decreasing the thickness of this layer can lead to a higher reflectance below the bandgap, but more data is needed to fully integrate the effect of doping concentration (using the Drude model) into these reflectance calculations. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 22-23).

A universal assistive door unlatching device

Wed, 01 Jan 2020 00:00:00 GMT

A universal assistive door unlatching device McKellar, Fiona(Fiona L.) A seemingly easy task for some, opening doors can cause frustration or pain for many people, due to difficulty spinning or gripping the handle. While technology does exist to make door handles more accessible or easy to use, there is no option that is low cost, quick easy to install, and will completely take away the need to grip or twist. This project focused on designing a method of unlatching doorknobs and handles that does not obstruct or change the pre-existing hardware of the door, can be easily installed and removed, and is compatible with most interior door handles. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 29-31).

Designing a device to create a metered two-phase mixture

Wed, 01 Jan 2020 00:00:00 GMT

Designing a device to create a metered two-phase mixture Miller, Elijah(Elijah B.) Foams are used in a variety of applications. It can be used as a lightweight structural component, has favorable heat transfer properties for use as an insulator, and commonly used to attenuate vibrations. Mixing a gas phase and a liquid phase requires energy input related to the surface tension of the liquid, and much higher than its thermal energy, as a large amount of bubbles must form. This thesis investigates the Tessari or two-syringe method of foam-making by attempting to scale the design from hand-operation to the use of pneumatic cylinders to accomodate more viscous fluids, or greater quantities. Based on mathematical modeling, the design can accommodate a maximum fluid viscosity exceeding 96.3 Pa-s (96,300 cps) through 1/8 NPT pipe with no restriction. A sintered metal filter was also modeled, resulting in restrictions that reduced the maximum viscosity to the order of 1 cps (10-3 Pa-s). Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 43).

Recycled material selection for affordable and sustainable homes using large scale additive manufacturing

Wed, 01 Jan 2020 00:00:00 GMT

Recycled material selection for affordable and sustainable homes using large scale additive manufacturing Mynio, Erika P. Worldwide estimates indicate nearly 150 million people are homeless, and 1.6 billion lack adequate shelter. One of the biggest barriers of home ownership is cost, which is often driven heavily by the cost of materials required. Plastic waste is also at an all-time high, with over 5 billion tons of plastic on the earth's surface and in its oceans. This waste will take hundreds of years to degrade if not longer and incentives and use for recycled plastic is needed now more than ever. Making lightweight homes using 3D printed recycled polymer materials is proposed as a solution to this problem. Assuming a network of manufacturing sites, a significant number of homes could be produced, raising the issue of material selection and availability. After creating an extensive comparison of potential materials, stressing properties, availability and cost, the best candidate appears to be polyethylene terephthalate (PET). Recycled PET (rPET), is available in volumes comparable to the projected demand for low cost housing. rPET material properties optimize the feasibility, processing, and engineering use qualities of the building material, but further testing is necessary to explore the effect of feedstock processing and additives on the performance of the material. This thesis examines the choice of (rPET) as the best potential material for large scale 3D printing of low-cost homes and presents an experimental setup for confirming this hypothesis. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 58-63).

Design of a mechanism to increase lateral force resistance of an autonomous ship hull cleaning robot

Wed, 01 Jan 2020 00:00:00 GMT

Design of a mechanism to increase lateral force resistance of an autonomous ship hull cleaning robot Morgan, Harith. Marine biofoul accrues on ship hulls and increases the resistance of a ship during voyage. This is a widespread issue within the shipping an industry -- which supports the vast majority of global trade. To address this problem, we are developing Bio-Inspired HullCrawler -- an autonomous robot capable of cleaning ship hulls while a ship is underway. The novelty of our design centers on the bio-inspired suction cups that are cast as composite silicon elastomer. The purpose of this thesis is to look specifically at the lateral force resistance of elastomeric suction cup mechanisms. Here we propose new design concepts for the attachment system to improve on the drag force resistance of the HullCrawler device. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 27).

Development and validation of a single mass Lap simulation

Wed, 01 Jan 2020 00:00:00 GMT

Development and validation of a single mass Lap simulation Noel, Jeremy R. In this thesis, a single mass model lap time simulation was designed, implemented and validated in MATLAB. The goal of this simulation was to accurately predict the velocity of a formula style open wheeled race car on a given track. The simulation was constructed in MATLAB, and features a function based design that will allow the core algorithm to be used with more sophisticated vehicle models. The code was tested and validated using a combination of contrived and collected map data, and a strong correlation of 0.8067 was shown with 95% confidence bounds of 0.8028, and 0.8105. Finally, this thesis outlines proper testing techniques to obtain the data required to complete the validation process of this simulation. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 63).

Design of a high performance liquid-cooled lithium-ion battery pack for automotive applications

Wed, 01 Jan 2020 00:00:00 GMT

Design of a high performance liquid-cooled lithium-ion battery pack for automotive applications Perrin, Ethan(Ethan B.) This thesis explores the design of a water cooled lithium ion battery module for use in high power automotive applications such as an FSAE Electric racecar. The motivation for liquid cooling in this application is presented with an adiabatic battery heating simulation followed by a discussion of axial cooling based on the internal construction of an 18650 battery cell. A novel design is proposed, implementing soldering the negative terminal of electroplated 18650 battery cells directly to a metal core printed circuit board material as the critical cell-to-water interface that provides high thermal conductivity while maintaining electrical isolation. Cold plate design, sealing, and manufacturing is discussed and implemented concluding with pressure and leak testing of a scale test article. Cell soldering efficacy is explored through testing of various low temperature solder alloys, fluxes, and surface plating to make recommendations on full scale module builds. A single cell test article is constructed and tested to validate thermal performance expectations with preliminary results suggesting constant power discharge rates of up to 60 W per cell is possible without overheating, which greatly exceeds the power requirements of existing FSAE Electric vehicles built by MIT Motorsports. Further work is needed to quantify solder joint reliability and examine thermal gradients present at the full module and pack scales. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 75).

On the feasibility of the Hyperloop Concept

Wed, 01 Jan 2020 00:00:00 GMT

On the feasibility of the Hyperloop Concept Rana, Yaseem. The Hyperloop is a ground-based transportation system proposed by Elon Musk in 2013 as a potential alternative to airplanes and high-speed rail. This thesis presents methods for first-order evaluation of design options for a Hyperloop system from technical and economic perspectives. The models are presented in generalized form so additional effects can be added by those with appropriate experience in the many different areas associated with long distance mass transport systems. The framework built in this thesis includes basic performance and cost analysis of the aerodynamics, levitation, propulsion, structure, and energy generation of a Hyperloop system. The first order models are intended to illustrate a process for investigating design trade-offs, but greater detail and domain specific expertise is needed to obtain realistic cost comparisons. The analysis culminates in a model to estimate the ticket cost for a Hyperloop route between any two cities, with many variables which can be input by the user to make conclusions about route feasibility. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 43).

Feasibility and technoeconomic analysis of small-scale biomass to power system with novel producer gas cleanup technology

Wed, 01 Jan 2020 00:00:00 GMT

Feasibility and technoeconomic analysis of small-scale biomass to power system with novel producer gas cleanup technology Sampson, Jonathan A. As global energy demand grows and climate change becomes an ever-evolving phenomenon, it is imperative that current energy systems are re-evaluated, and new energy systems begin to penetrate global markets. In the developing world, a number of factors make small-scale biomass to power systems an interesting proposition. One such iteration of this technology involves novel producer gas cleanup and tar removal, where instead of using chemical processes, the system employs rich partial combustion through auto-ignition to destroy tars in vapor form above 300°C. This investigation serves to technically and financially analyze the feasibility of this system using experimental data found through testing of the cleanup engine to inform the theoretical design of the remainder of the system. 22kWe was selected as the system electric power output. Based on these results, it was determined that a 3.08-liter engine would be necessary for cleanup, and a 4.58-liter engine would be necessary for downstream power generation at 22kWe. This corresponds to a capital cost of $9,600, which is 34% of the retail price of current similar systems. This results in a levelized cost of energy range of $0.07 per kWh to $0.34 per kWh depending on the cost of biomass feedstock. This range is large for a levelized cost of energy, but shows that this system can be financially competitive in certain settings depending on the local fuel cost, proximity to biomass feedstock, and electricity needs.. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 40-41).

Design of a two-stage multi-state experimental biogas reactor

Wed, 01 Jan 2020 00:00:00 GMT

Design of a two-stage multi-state experimental biogas reactor Stampfli, John J. Anaerobic digestion is a process that breaks down waste and other feed materials and produces biogas. A biogas reactor, or anaerobic digester, is designed to conduct anaerobic digestion in a closed environment and to collect the produced biogas. This is an important field of study because biogas is a renewable energy source. If it can be produced more efficiently, it may become a feasible alternative source of green energy. This thesis outlines the design of a lab-scale experimental reactor with a large range of functionality. The design permits many different environmental conditions, allowing anaerobic digestion to be thoroughly studied with one setup. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 23-25).

Rheometric measurement of hydrogel toughness

Wed, 01 Jan 2020 00:00:00 GMT

Rheometric measurement of hydrogel toughness Read, Helen E.S.B.Massachusetts Institute of Technology. As soft physical gels become more popular due to their biological applications, there is increased interest in measuring mechanical properties such as toughness. However, traditional tensile testing methods do not work for such materials due to the intrinsic softness of the material. We present a novel method for measuring fracture energy using a rheometer and show it is broadly consistent with the pure shear test, a standard method where the material exhibits mode I fracture. This method has potential applications in characterizing a wide range of soft and transient gels. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 11-12).

The effects of geometrical changes on airflow of developing-world solar fruit dryers

Wed, 01 Jan 2020 00:00:00 GMT

The effects of geometrical changes on airflow of developing-world solar fruit dryers Tang, Lisa(Researcher in mechanical engineering)Massachusetts Institute of Technology. Small fruit-drying operations are becoming increasingly prevalent in the developing world. Many of these operations rely on solar thermal dryers with small fans to induce active air flow, which enhances drying capabilities. This thesis examines the effects of changes in dryer geometry on the air flow within flatbed solar dryers. The interior of a dryer was simulated using Ansys Fluent, and air flow velocity and patterns were observed as the dryer's length, width, and height were varied. It was found that a small fan placed at the dryer's entrance introduces a thin jet of air, which slows and spreads out over the course of the dryer. A steady air flow pattern was reached 4 meters into the modeled dryer. Reducing dryer height was found to increase the air flow velocity at the dryer's center, but not at the dryer's bottom where fruit is usually located. In addition to decreasing dryer height, the study recommends vertically raising the racks of fruit further above the dryer bottom. Air flow consistency across the width of the dryer persisted as an issue through the variations of width and height. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 43-45).

Design and evolution of creative capacity building program for refugee youth empowerment

Wed, 01 Jan 2020 00:00:00 GMT

Design and evolution of creative capacity building program for refugee youth empowerment Tenali, Srimayi. There are over 5,000 unaccompanied refugee minors in Greece who have fled violence from Syria, Pakistan, Afghanistan, and Iraq. In addition to pre-existing trauma and psychological challenges, living in shelters and streets has further put youth at risk of trafficking, exploitation, and substance abuse. In 2017, MIT D-Lab partnered with Faros, a Greek NGO, to develop a design workshop for the unaccompanied minors. At the end of training, they demonstrated an improved capacity to identify and solve challenges, work in teams, and recognize self-potential. Since then, this weeklong design workshop has evolved into a multi-stage, modular training program taught over several months. The purpose of this study was to identify the successes and failures of each developmental stage of this program to determine overarching trends for building a design curriculum for vulnerable youth populations. Analysis revealed that cultural significance, flexible structure, and addressing social and behavioral concerns are among the key elements for effectively reaching refugee youth. By documenting the evolution and implications of these factors, we hope to provide a baseline for future education work with this unique and vulnerable population. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 40-41).

Optimizing the efficiency and filter area of the SurgiBox Environmental System by redistributing effective media area across filter length

Wed, 01 Jan 2020 00:00:00 GMT

Optimizing the efficiency and filter area of the SurgiBox Environmental System by redistributing effective media area across filter length Walter, Sandra L. Across the globe, billions of people lack access to safe surgery. SurgiBox is working to lower that number by creating a portable surgical environment for patients in need. To do this, they are working to improve their air filtration system by better utilizing filter media to create a more efficient system. To help SurgiBox achieve this goal, Solidworks Flow Simulation Models were created and analysed to determine what parameters would be necessary to achieve a goal of a uniform velocity profile while meeting volumetric flow rate specifications. These models show that it is possible to achieve a uniform velocity distribution by using filters with varied resistances to air flow. It was found that, neglecting edge effects, the pressure drops (at a defined velocity) of the filter follow a linear trend across the length of the filter. However, these models also show that edge effects lead to significant air flow inconsistencies revealing that if these edge effects are not addressed, the system may quickly fall out of specification. Numerically generated "ideal" system centerline velocity and pressure curves were created to be used as comparative tools while conducting experiments on the SurgiBox system. These, in combination with the SolidWorks models will inform design changes to the SurgiBox system and help the SurgiBox team quantitativly assess the quality of their designs. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 46).

Design, analysis, and validation of Interface electronics for use in axially coupled 2-DOF brushless motor control system

Wed, 01 Jan 2020 00:00:00 GMT

Design, analysis, and validation of Interface electronics for use in axially coupled 2-DOF brushless motor control system Wiest, Daniel Tortora. This thesis describes the design, assembly, and (abbreviated) validation of the interface electronics and housings required to drive and receive position feedback from two brushless motors with a National Instruments myRIO embedded real-time evaluation board. Eight LT1167 instrumentation amplifiers are used in combination with four AD790 high speed comparators to appropriately scale, threshold, and isolate the encoder position data and control output commands. The interface board was designed such that it does not require any additional power supplies for operation and can withstand use by students in a laboratory context. The resulting interface board eliminates the possibility of improper connection, which in the past, has resulted in the destruction of several encoder systems. Students utilizing this board can explore a variety of topics including but not limited to modes of brushless motor commutation, sine-cosine encoding, quadrature encoding, and multi-input multi-output (MIMO) control systems. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 38).

Evaluating a multi-jet Impingement air heat exchanger design for PEBB 6000 using Solidworks Flow Simulation

Wed, 01 Jan 2020 00:00:00 GMT

Evaluating a multi-jet Impingement air heat exchanger design for PEBB 6000 using Solidworks Flow Simulation Wu, Qingmei,S.B.Massachusetts Institute of Technology. The Power Electric Building Block (PEBB) 6000 is a shipboard power converter unit developed by the Navy's Electric Ship Research and Development Consortium (ESRDC). Cooling strategies for the PEBB 6000 are constrained by its size, accessibility, and high heat flux. This paper proposes an air heat exchanger design that combines a parallel plate-fin heat sink with air jet impingement onto its fins. Previous studies showed that jet impingement methods can yield heat transfer rates that are three times of those produced by conventional cooling methods, which confines a parallel flow to a surface. In order to evaluate the design feasibility of a multi-jet impingement air heat exchanger, this paper simulates the temperature contours and the flow trajectories for various multi-jet impingement models using SOLIDWORKS Flow Simulation in two stages. First, multi-jet impingement models with varying number of nozzles, nozzle diameters, impingement heights, arrangements, and velocity configurations were simulated for a single parallel plate fin. Cooler fin temperatures were achieved with larger diameter size, smaller impingement height, higher inlet velocity, and more nozzles. In the second stage, a model for the multi-jet air heat exchanger was created. When compared with simulation results for the heat sink with conventional parallel air flow, the fin thermal resistance of the heat sink was reduced by approximately 60 percent and the heat transfer rate was increased by almost threefold with the multi-jet impingement heat exchanger setup. These results help assess the potential of using a multi-jet impingement heat exchanger to cool the PEBB and provide valuable insight to improve future models. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 59).

Ultraportable surgical enclosure : human centered design for high usability in unpredictable environments

Wed, 01 Jan 2020 00:00:00 GMT

Ultraportable surgical enclosure : human centered design for high usability in unpredictable environments Zhang, Annie Tianci. Access to safe and sterile surgical infrastructure dramatically reduces the risk of infection for both patients and medical providers. However, this access is limited for many, especially those in austere environments and developing countries. SurgiBox is a product that aims to solve this problem by providing a sterile surgical micro-environment in a cost-effective manner. SurgiBox is a transparent, inflatable plastic enclosure which isolates the surgical site, creating a localized, sterile region in which surgical procedures may take place. The two primary markets -- humanitarian and defense applications -- have overlapping needs and similar design constraints. For both markets SurgiBox needs to be highly portable and useful in unpredictable environments with ad-hoc medical infrastructure. Using SurgiBox should be a predictable, reliable, and easy to understand experience even in the most unpredictable environments. The redesign of SurgiBox components through a Human Centered Design approach has enhanced its usability, effectiveness, and efficiency for both patients and medical providers. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 28).

Comparing the efficacy of fiber reinforced actuators to replicate inhalation vs. exhalation

Wed, 01 Jan 2020 00:00:00 GMT

Comparing the efficacy of fiber reinforced actuators to replicate inhalation vs. exhalation Zollinger, Lyndie. Fluid Powered Elastomeric Actuators are a class of soft robotic actuators of particular interest for biomimetic designs because researchers can replicate certain motions by tailoring the mechanical properties of the actuator through the use of different fibers and materials. [1] Hu et al. showed that pre-curved fiber-reinforced actuators could be used to mimic more complex geometries and motions. [2] Optimization techniques for determining optimal fabrication parameters for such actuators were developed by Hu et al. from a modified version of Connolly et al.'s technique to generate fiber reinforced actuators optimized to follow a given input trajectory. [2, 1] This modified optimization technique was adapted for the specific application of creating biomimetic actuators to follow the motion of the human diaphragm. [2] The technology relies on extracting motion trajectories from clinical imaging data.; This work analyzes and optimizes Hu et al.'s assumptions in visually choosing a planar location for the diaphragm anchoring point into the ribs based off of pixel locations within a Magnetic Resonance Imaging (MRI) scan in order to choose actuators to fabricate for further testing. We conducted a sensitivity analysis on the effect of varying this assumed anchoring point over a span of 3.1cm. We found no statistically significant differences in the mean error of the fabrication datasets corresponding to three selected anchoring location values. We determined that an assumed offset of 130 pixels (28.9 cm from the top of the image) provided an optimal compromise for minimizing error while still being a biologically realistic assumption. This fabrication dataset was thus selected for further development. Computer-aided design (CAD) models of the actuators were developed and used in creating molds. The actuators were then manufactured using the developed molds.; Due to the complex nature of studying generated forces on a curved actuator, a modular test fixture compatible with minor modifications to the molds was developed for an Instron test setup. The test fixture was developed and prepared for testing. The future results of this testing will provide further insights into the feasibility of developing a soft robotic biomimetic diaphragm. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 61).

Responsive wearables for rheumatoid arthritis

Wed, 01 Jan 2020 00:00:00 GMT

Responsive wearables for rheumatoid arthritis Fang, Jierui. The purpose of this thesis is to investigate and create more responsive and adaptive assistive technology for patients with rheumatoid arthritis (RA), using computational design methods to embed individualized data within the design and materiality. Rheumatoid arthritis is a chronic, autoimmune disease that attacks the joints and causes progressive deformity and bone erosion directed mostly at joint linings and cartilage. Living with RA means sudden flare-ups of pain and inflammation that can last anywhere from hours to months and dramatically impact the ability to accomplish ordinary tasks. While there is no cure, the disease can be slowed down through intensive drugs and or mitigated with assistive wearable devices such as braces, splints, and compressive gloves. These wearables are used to minimize swelling in affected joints, lessen ulnar deviating forces, and reduce pain. However, many people are unwilling to wear these devices because they can be quite obtrusive and hinder patients' lifestyles. Most wearables are only available in set sizes, and when sized incorrectly can aggravate pain and symptom flare-up or have no healing benefits. This thesis asks whether and how computational design methods can be applied to alleviating unique pain points faced daily by people with chronic health issues such as RA and other physical joint or musculature needs. Given that each person suffering from rheumatoid arthritis manifests the debilitating effects of the disease in different ways, this leads to the question of how more effective and personalized assistive devices can be designed using computational design methods that do not put the onus on the user to perform corrective action, but rather automatically offer responsive support as needed. Thesis: S.B. in Art and Design, Massachusetts Institute of Technology, Department of Architecture, May, 2020; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 34-36).

A new paradigm of perception

Wed, 01 Jan 2020 00:00:00 GMT

A new paradigm of perception Abubakar, Zidane. What we experience on a day to day basis, our reality, is dictated by what we see, hear, feel, taste and smell - what we sense. These daily experiences are directly tempered by our perceptions. On one end of the spectrum, the hearing or visually impaired may experience fewer senses than most. On the other end of the spectrum exist synesthetes - people with the condition known as synesthesia, and who experience a reality with blended senses. Synesthesia is a condition in which stimuli in one sense involuntarily and automatically trigger perceptions in another sense. The unique experience that this extra layer of perception presents could potentially revolutionize the human experience by offering a new paradigm of creation and perception. Unfortunately, synesthesia is a very rare phenomenon that only affects a very small portion of the population. There have been some successful endeavors to replicate a variety of different forms of synesthesia, from art installations to audiovisual performances. While they are interesting utilizations of synesthesia, these replications aren't accessible or widely known to the general public, and so the potential for this revolution has not been fully realized. This thesis asks the question: How can we learn from synesthesia to discover and design new, useful, and accessible ways of perceiving the world? This thesis theorizes possible ways of creating new sensory experiences that utilize synesthesia as a model in order to create new, enhanced perceptions that are as accessible as possible to the general public. Specifically, this thesis will focus on creating a new sensory experience, the realm of which will be influenced by results from a survey of the MIT population, with Arduino tools, as they grant access to a great deal of senses and are relatively cheap and easy to construct. Thesis: S.B. in Art and Design, Massachusetts Institute of Technology, Department of Architecture, May, 2020; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 50-51).

The effect of time upon the elongation and set of copper and composition wires

Wed, 01 Jan 1913 00:00:00 GMT

The effect of time upon the elongation and set of copper and composition wires Chow, H. K.; Keh, S. S. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1913; Includes bibliographical references (leaf 11).

Effect of coriolis force on the turbulent boundary layer in rotating fluid machines

Wed, 01 Jan 1964 00:00:00 GMT

Effect of coriolis force on the turbulent boundary layer in rotating fluid machines Moon, I. Man. Thesis (Mech.E)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1964.; Includes bibliographical references (leaf 17).

Experimental problems in nuclear reaction studies

Sun, 01 Jan 1961 00:00:00 GMT

Experimental problems in nuclear reaction studies Kwok, Philip Chi-Kuen. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1961.; Includes bibliographical references (leaf 61).

An investigation of submillimicrosecond light sources

Sun, 01 Jan 1961 00:00:00 GMT

An investigation of submillimicrosecond light sources Kutsko, Michael James. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1961.; Includes bibliographical references (leaf 40).

Color centers in calcite

Sun, 01 Jan 1961 00:00:00 GMT

Color centers in calcite Kolbe, William Frederick. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1961.; Includes bibliographical references.

Alpha particle sources for calibration purposes

Sun, 01 Jan 1961 00:00:00 GMT

Alpha particle sources for calibration purposes Klages, Karlene Corbit. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1961.; Includes bibliographical references (leaf 50).

Stimulated optical emission in ruby

Sun, 01 Jan 1961 00:00:00 GMT

Stimulated optical emission in ruby Keck, Max Johann. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1961.; Includes bibliographical references (leaf 24).

The operation characteristics of a semiconductor detector

Sun, 01 Jan 1961 00:00:00 GMT

The operation characteristics of a semiconductor detector Huang, Philip Tsung-Fu,1938- Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1961.; Includes bibliographical references (leaves 20-21).

The production and study of a thermally ionized cesium plasma

Sun, 01 Jan 1961 00:00:00 GMT

The production and study of a thermally ionized cesium plasma Kulpa, Stanley M.; Hilton, Wesley W. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1961.; Includes bibliographical references (leaf 25).

Comparison of the spectrum line width of Dy₁₆₂ and "natural" Dy

Sun, 01 Jan 1961 00:00:00 GMT

Comparison of the spectrum line width of Dy₁₆₂ and "natural" Dy Hill, Tony C.(Tony Charles) Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1961.; Includes bibliographical references (leaf 29).

A histological and immunological response study of an implantable microcapsule drug delivery device for the treatment of glioblastoma

Sun, 01 Jan 2012 00:00:00 GMT

A histological and immunological response study of an implantable microcapsule drug delivery device for the treatment of glioblastoma Van Schaik, Graham(Graham W.) Glioblastoma Multiform (GBM) and the more prevalent metastatic brain tumor are some of the most deadly forms of cancer, accounting for the death of nearly 14,000 individuals yearly. Previous treatment options for brain cancers include tumor resection, radiation, and chemo therapy but such options provide limited success in prolonging patients' life. Most patients experience tumor recurrence near the resected areas within a few months and are ineligible for additional rounds of chemotherapy due to systemic toxicity associated with many chemotherapeutic drugs. Advances in implantable drug delivery devices look promising, but can suffer from the possibility of biofouling, or loss of function due to a patient's own immune response. An implantable microcapsule device, designed to deliver locally chemotherapeutics in the brain, was developed by Alex Scott and Yoda Patta in the Cima Lab at the MIT Koch Institute for Integrative Cancer Research.; The device passively delivers a payload of two common chemotherapeutics, Doxorubicin HCI or Temozolomide, and can be inserted post tumor resection to limit the possibility of tumor recurrence. In vivo implantation and sham surgeries using the device cap were performed on Sprague Sawley rats to assess an immune response and to look for potential biofouling 3, 7, 14, and 28 days post surgery. Immune response was quantified using a [mu]BCA assay for total protein concentration and an ELISA targeting Glial Fibrillary Acidic Protein (GFAP). Histology assays targeting 3 markers for new cell growth GFAP, NeuN, and CD68, were performed to determine relative location and prevalence of potential biofouling. Histological analysis offered little insight in the potential for biofouling near the implantation site as little fluorescence was seen for any markers.; Fluorescence was slightly higher on the edge of the implantation wound site, but this may have been due to factors other than the increased presence of protein. ELISA and [mu]BCA analysis suggested that the immune response was activated and biofouling a possibility as total protein concentration was significantly higher 3 days post surgery than that seen at later time points (p < 0.05) and GFAP concentration for implantation groups remained elevated throughout the study. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2012; Cataloged from the PDF of thesis.; Includes bibliographical references (pages 40-42).

Designing public transit at the margins

Wed, 01 Jan 2020 00:00:00 GMT

Designing public transit at the margins Jacobsen, Adriana(Adriana M.) Boston's public transportation network, the MBTA, is a "hub-and-spokes" system: rail lines radiate out to the suburbs from a few central downtown stations, and traveling between the "spokes" often requires taking multiple buses or traveling all the way inbound in order to transfer. Particularly on the bus and Commuter Rail systems, off-peak service is limited. For those who live in the suburbs and commute to the city during rush hour, this setup works relatively well. However, many women that depend on public transportation face unique difficulties. Women are more likely to make care-related and household-sustaining trips such as grocery runs and dropping off and picking up children from school, to make multiple trips in a row (trip-chaining), and to feel unsafe on public transit. Understanding the limitations that transit-reliant women face can help to build a more comprehensive public transit system that supports all types of trips and improves public transportation for everyone, following the theory of "designing from the margins." Using data from a survey I conducted of almost 200 women in the Boston area, I examine some of the issues and obstacles that these women face when using public transit, suggest some design guidelines for new transit infrastructure, and imagine how the MBTA could change to accommodate the travel patterns of the women surveyed. Thesis: S.B., Massachusetts Institute of Technology, Department of Urban Studies and Planning, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 58-60).

The role of open government data in Boston's climate adaptation process

Wed, 01 Jan 2020 00:00:00 GMT

The role of open government data in Boston's climate adaptation process Lin, Jackie J.S.B.Massachusetts Institute of Technology. This thesis asks the question, what is the role of open government data? Has the open aspect of open government data democratized participation to create more insightful, just, equitable, and inclusive action or research? Studying open government data use is important because more efforts can be made to replicate successes and bridge gaps between reality and perceived benefits. To examine this question, this thesis uses Boston, Massachusetts as a case study. The City of Boston is a leader in municipal climate adaptation, and has worked with a diverse set of private, public, non-governmental, and academic actors to create and implement resilience initiatives for their climate adaptation plan Climate Ready Boston. Boston's open data initiative and its context in the broader national open government data environment hints at potential influence of open government data on Climate Ready Boston. In this thesis, I study traces of open government data in Climate Ready Boston's ecosystem of actors to understand the role of open government data in climate adaptation. Two network maps were produced to identify the relationships and information exchanges in an attempt to trace the role and presence of open data. The results suggest current minimal usage of open government data in Climate Ready Boston, and that Boston climate adaptation could benefit from increased collaboration between academic institutions and local nonprofit organizations to create valuable insights from open government data.. Thesis: S.B., Massachusetts Institute of Technology, Department of Urban Studies and Planning, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 53-57).

The dual nature of rent growth : a theory-based approach to the housing choice voucher program

Wed, 01 Jan 2020 00:00:00 GMT

The dual nature of rent growth : a theory-based approach to the housing choice voucher program McDaniel, Noah Jefferson. The Housing Choice Voucher program is the largest low-income housing subsidy program in the U.S., serving over 2.2 million households annually. The Department of Housing and Urban Development provides the same subsidy level for program participants, whether new and searching for a unit, or continuing. In its design of the subsidy amount, the Fair Market Rent, HUD negotiates the balance between enabling voucher holders to access better quality housing, and spending efficiently. In this thesis, I argue that the FMR methodology does not recognize the different mechanisms that influence rent for available units, compared to continually occupied units. Through a theoretical model and empirical analysis of a case study in San Francisco, I present a new methodology with two subsidy levels - one for searching voucher holders, and one for continuing voucher holders. This proposal builds on the theory presented and considers the implications for program budget and decision making for the agents involved. Thesis: S.B., Massachusetts Institute of Technology, Department of Urban Studies and Planning, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 21-22).

Using machine learning, particle tracking, and grain shape modeling to characterize bedƯload sediment transport

Wed, 01 Jan 2020 00:00:00 GMT

Using machine learning, particle tracking, and grain shape modeling to characterize bedƯload sediment transport Rushlow , Matthew R.S.B.Massachusetts Institute of Technology. Rivers are generally understood through their bulk characteristics and on a river by river scale, while the motion and characteristics of the individual sediment that progresses through those rivers is poorly understood. This project sought to track the bed-load transport of individual natural and artificial sediment grains through a flume to understand the effects of grain shape on motion, and creation of multi spherical approximations of natural sediment grains for use in numerical simulations. Machine learning tools processed the position of millions of grains through a flume. Successful identification and tracking of nearly 75% of all grains within a flume, and multi spherical approximations of natural grains using 20 spheres or less that reproduced important shape characteristics of natural grains were achieved. Accurate grain locations allowed the possibility for velocities, accelerations, entrainments, and flux to be studied with uniquely high resolution. Efficient flume simulations that better represent actual sediment became possible. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 39-41).

Assessment of a compact steam generator aided by computational fluid dynamics

Wed, 01 Jan 2020 00:00:00 GMT

Assessment of a compact steam generator aided by computational fluid dynamics Aranda Ocampo, Brandon Ariel. Steam generators are an essential component in nuclear power plants which serve to transfer thermal power from a liquid coolant to steam by boiling water. Even with many advancements in the designs of steam generators, they still require extremely large sizes and have high costs which are major hurdles for the implementation of new reactor designs such as Small Modular Reactors. Using a Printed Circuit Heat Exchanger (PCHE) such as those from the company HeatricTM as a steam generator to boil the liquid in the secondary side has potential to overcome the disadvantages of conventional steam generators. Computational Fluid Dynamics was used to aid the assessment of such compact steam generator. The models used were bench marked against a 1-D MATLAB code which simulated a compact steam generator with straight, semi-circular channels. The same conditions were used to simulate a zig-zag, semi-circular PCHE. The zig-zag configuration resulted in a 22 °C increase in superheat over the straight channel configuration at the cost of pressure drops that are over 4 times higher but yet easily accommodated. The PCHE was also simulated in different orientations with respect to gravity and determined there is little advantage in using a vertical layout regarding pressure drop for the zig-zag configuration. Plugging of a single channel was also simulated to determine the effect on surrounding channels and potential hot spots. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 63-65).

Development of an experimental technique to investigate droplet cooling phenomena on accident tolerant fuel materials

Wed, 01 Jan 2020 00:00:00 GMT

Development of an experimental technique to investigate droplet cooling phenomena on accident tolerant fuel materials McGhee, Warner(Warner A.) Droplet cooling is used in many heat removal applications, including core spray coolers in boiling water reactors. As new accident tolerant fuels are developed, understanding how they respond to droplet cooling is important to ensuring safe operations. Recent studies have indicated that surfaces engineered with micro- and nanostructures may affect the Leidenfrost point temperature of water and thus the efficiency of droplet cooling by altering the wettability of the surfaces. In this project, smooth and rough chromium surfaces were subjected to droplet cooling at temperatures ranging from 100 to 400°C, and the surface temperature was measured with a high speed infrared camera while a video camera observed the droplet shape and behavior during boiling. While the rough and smooth surfaces performed similarly at temperatures below 200°C, the data indicates that at higher temperatures the smooth surface allows for greater heat flux, longer droplet contact time, and more total heat removed. The sparsity of data makes this result very uncertain, especially since it seems to oppose most literature on the topic. The techniques developed for this study are promising for future illumination how surface structure affects droplet cooling. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 51).

Application of genetic algorithm and deep reinforcement learning for in-core fuel management

Wed, 01 Jan 2020 00:00:00 GMT

Application of genetic algorithm and deep reinforcement learning for in-core fuel management Reed, Jane C.,S.B.Massachusetts Institute of Technology. The nuclear reactor core is composed of few hundred assemblies. The loading of these assemblies is done with the goal of reducing its overall cost while maintaining safety limits. Typically, the core designers choose a unique position and fuel enrichment for each assembly through use of expert judgement. In this thesis, alternatives to the current core reload design process are explored. Genetic algorithm and deep Q-learning are applied in an attempt to reduce core design time and improve the final core layout. The reference core represents a 4-loop pressurized water reactor where fixed number of fuel enrichments and burnable poison distributions are assumed. The algorithms automatically shuffles the assembly positions to find the optimum loading pattern. It is determined that both algorithms are able to successfully start with a poorly performing core loading pattern and discover a well performing one, by the metrics of boron concentration, cycle exposure, enthalpy-rise factor, and pin power peaking. This shows potential for further applications of these algorithms for core design with a more expanded search space. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 21).

Developments and benchmarking applications for Grasshopper : a Geant4 based physics simulation tool

Wed, 01 Jan 2020 00:00:00 GMT

Developments and benchmarking applications for Grasshopper : a Geant4 based physics simulation tool Miske, Jacob N. Current particle physics simulations take place largely within small communities developing limited tools for specific areas of study. These particle simulations are essential to evaluating environments outside of the realm of experimentation in the radiation sciences. While multi-use toolkits exist for particles simulation (such as the popular MCNP or SRIM programs), these computational tools are often difficult for untrained users to adapt into their projects. Geant4 is one such toolkit that is used widely by physicists in radiology, fission reactor work, and space irradiation studies among many other fields. As it happens, Geant4 and related programming libraries are not the default program to install and use for scientific simulations by physicists or the general public interested in this work. However, a widely applicable simulation engine using Geant4, called Grasshopper, has been developed to allow for generating straightforward Monte Carlo simulations for engineers and scientists in a wide range of fields. This thesis evaluates Grasshopper with a series of benchmarks that show the software is able to accurately match empirical results. These benchmarks evaluate the accuracy of Grasshopper to run simulations involving alpha, proton, beta, gamma, and neutron radiation in the range of 1 MeV to beyond 100 MeV. By allowing users of Geant4 to easily generate these simulations, the time it takes to develop insights can now be reduced further with the increased efficiency from the use of these tools. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 36).

Evaluation of material attractiveness to non-state actors of various nuclear materials in Thorium fuel cycles

Wed, 01 Jan 2020 00:00:00 GMT

Evaluation of material attractiveness to non-state actors of various nuclear materials in Thorium fuel cycles Lisowski, Eva. Thorium-based fuel cycles for advanced nuclear reactors have been explored to utilize thorium resources in nations where uranium is scarce, increase fissile material utilization, and enhance proliferation resistance. As a stepping stone, thorium-based fuels have been paired with pressure tube heavy water reactors because of their high neutron economy and online refueling capability. However, thorium fuel cycles have raised proliferation concerns regarding the presence of U-233 following the irradiation of fuel bundles. The presence of Pa-233, which decays into pure U-233, and the creation of Pu-239 due to the neutron capture of U-238 in mixed lightly-enriched uranium (LEU)/Thorium fuels, are also causes for proliferation concern.; Based on a method developed in a previous study, the material attractiveness to non-state actors of fissile materials present in a 40%LEU/60%Th fuel lattice concept was evaluated for six metrics: bare critical mass (BCM), heat content, net weight, acquisition time, dose rate, and processing time & complexity. The lattice, composed of 35 fuel pins and a central ZrO2 displacer rod, was modeled and depleted in the OpenMC reactor physics software, over a range of burnups up to 40 MWd/kg followed by two years of cooling. It was found that the material attractiveness of uranium isotopes in the irradiated fuel bundle was Very Low due to the high fraction of U-238 present in the fuel and the assumed lack of enrichment capabilities among non-state actors. However, for a state with basic enrichment capabilities, this fuel may be attractive. The attractiveness of plutonium isotopes was also found, as expected in a thorium-cycle, to be Very Low.; However, the low BCM and heat content of this mixture reveals that it could be attractive to states that can easily acquire the material and do not need to rely on the theft of many fuel bundles to acquire an IAEA Category I quantity of material. Further investigation of the material attractiveness to states is required. Material attractiveness evaluations are important to informing future decisions regarding which fuel bundles to select when designing advanced reactor facilities and developing methods to safeguard them. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 42-43).

Mapping and analyzing nuclear weapons programs development

Wed, 01 Jan 2020 00:00:00 GMT

Mapping and analyzing nuclear weapons programs development Strei, Thomas J.III. An in-depth review of the types of nuclear reactors and their relationship to the development of nuclear weapons was conducted in order to provide a better understanding of the intention of a state in the creation of an internal nuclear program. An analysis of countries that have developed nuclear weapons and countries that have not was conducted. Following this analysis, the relationship between the weapons program, or lack thereof, was compared to the research reactors possessed by the country. The political environment of the country was also taken into account in order to determine the motivations behind the nuclear weapons development. It was concluded that there are a myriad of factors at play in the decision made by a country to develop nuclear weapons. There is a direct correlation between the construction of research reactors that were previously utilized for weapons research and the pursuit of an independent nuclear weapons program. However, a political impetus is necessary for the proper motivation to develop nuclear weapons to exist. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 23-25).

Tufa-based reconstructions of Huasco Basin Lake levels

Wed, 01 Jan 2020 00:00:00 GMT

Tufa-based reconstructions of Huasco Basin Lake levels Tweedy, Ruth Rosegrant. This thesis investigates the Salar del Huasco (northern Chile) as a potential site for palaeohydrological reconstructions of precipitation over the South American Altiplano, and presents a preliminary lake level chronology for the last deglaciation. Resolving the timings of past lake level highstands in the South American Altiplano will ultimately provide better understanding of what climate events force the South American Summer Monsoon (SASM) further south. Better insight into the forcing mechanisms of the SASM will improve our understanding of monsoon systems, and can be applied to refine global climate models of the region. To create this lake level chronology, tufa samples deposited at different elevations within the Salar del Huasco were dated using U/Th disequilibrium dating, and stable isotope measurements were applied to examine the past hydrology of the basin. The Salar del Huasco was found to have remained a hydrologically closed basin during highstand events, meaning lake level variations within the basin are purely driven by local precipitation-evaporation balances. Furthermore, the preliminary lake level chronology broadly agrees with the timings suggested by other palaeohydrological studies from the region, and provides support for a currently controversial lake level highstand between 120-100 ka. These results imply that the Salar del Huasco accurately reflects SASM-forced lake level histories, and should be studied further. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 55-58).

Relationship Between West African monsoon precipitation characteristics and maize yields across Sub-Saharan West Africa

Wed, 01 Jan 2020 00:00:00 GMT

Relationship Between West African monsoon precipitation characteristics and maize yields across Sub-Saharan West Africa Shiu, Janice. Sub-Saharan Africa faces significant challenges to its food security in the coming decades as climate change and rapid population growth strains its agricultural systems. In a region where crops are near exclusively rainfed, precipitation from the West African Monsoon (WAM) plays a significant role in the region's food production. This study aims to add to the limited literature on the relationship between country-level maize yields and the WAM, particularly through the use of high resolution precipitation estimates to characterize the spatiotemporal variability of the monsoon. Multi-year annual precipitation characteristics of the monsoon such as total precipitation, number of non-precipitating days, and timing were derived and aggregated across the maize growing regions of West African countries. Aggregated precipitation metrics were linearly regressed against country-level maize yields that have undergone timeseries analysis to remove trends occurring independently of the WAM. The metrics most correlated with maize yields while maintaining statistically significant slopes were the minimum of total precipitation, standard deviation of the number of non-precipitating days, and the minimum monsoon end date. The strong positive correlations of the minimum of total precipitation and minimum monsoon end date metrics suggest that the worst performing areas in terms of total precipitation and monsoon end date drive down annual country-level maize yields. The positive correlation found using the standard deviation of the number of non-precipitating days is uninterpretable as an instance of Simpson's paradox, as the opposite relationship is discovered in analyses using individual countries. These results show the efficacy of analyzing maize yields against satellite mapped precipitation characteristics of the WAM. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 27-32).

Exploring the silicification of microbes and understanding their role in the fossil record

Wed, 01 Jan 2020 00:00:00 GMT

Exploring the silicification of microbes and understanding their role in the fossil record Morgenstein, Kyle J.(Kyle Jarad) Filamentous cyanobacteria that built macroscopic tufted mats in Proterozoic peritidal environments were fossilized by silicification, but the environmental and biological factors that shaped these structures and enabled this type of preservation are not well understood. Recent work has shown that coccoidal cyanobacteria can become fossilized because they can sequester silica from seawater that is undersaturated with respect to silica. Here, we use taphonomy experiments to demonstrate that filamentous cyanobacteria that form tufted and conical mats are also able to mediate the precipitation of silica in seawater that is undersaturated with respect to silica as well. These results show that different marine cyanobacteria and their macroscopic structures have a high potential to be preserved by silicification. We find that the exterior of macroscopic structures such as tufts and pillars are preferentially silicified, and more completely silicified at silica concentrations below saturation in seawater. The interior of these structures may be preserved by later diagenetic minerals. These results are consistent with microfossil assemblages found in early diagenetic chert deposits throughout the Proterozoic. The data suggest abundant Ca-rich sulfated polysaccharides in the exopolymeric substance (EPS), which are likely the site of silicification. Interactions among similar organisms, seawater chemistry, and silica in evaporative environments may account for the two-billion-year long record of exceptionally silicified filamentous and coccoidal cyanobacteria and their macroscopic aggregates in peritidal environments. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages [24]-[29]).

Characterization of solar X-ray response data from the REXIS instrument

Wed, 01 Jan 2020 00:00:00 GMT

Characterization of solar X-ray response data from the REXIS instrument Cummings, Andrew T. The REgolith X-ray Imaging Spectrometer (REXIS) is a student-built instrument that was flown on NASA's Origins, Spectral Interpretation, Resource Identification, Safety, Regolith Explorer (OSIRIS-REx) mission. During the primary science observation phase, the REXIS Solar X-ray Monitor (SXM) experienced a lower than anticipated solar x-ray count rate. Solar x-ray count decreased most prominently in the low energy region of instrument detection, and made calibrating the REXIS main spectrometer difficult. This thesis documents a root cause investigation into the cause of the low x-ray count anomaly in the SXM. Vulnerable electronic components are identified, and recommendations for hardware improvements are made to better facilitate future low-cost, high-risk instrumentation. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 67-68).

Investigating the influence of spin-curvature coupling on extreme mass-ratio inspirals

Wed, 01 Jan 2020 00:00:00 GMT

Investigating the influence of spin-curvature coupling on extreme mass-ratio inspirals Hanselman, Alexandra. In this report, extreme mass ratio inspiral worldlines and gravitational waveforms were produced considering radiation reaction and spin-curvature effects. Spin-curvature coupling was predicted to modify the inspiral by introducing oscillations to the small body's worldline. Investigating these effects led to the observation that spin-curvature effects introduce a resonance-like feature in the worldline. This feature is affected by the mass ratio, spin axis phase angle, and eccentricity of the system. The modifications to the inspiral worldline imprint themselves in the gravitational waves produced. Understanding how spin-curvature coupling modifies these waveforms will help gravitational wave detectors characterize the types of systems they detect. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 49).

Stress evolution of thin film RuO₂ Li-ion battery electrodes

Wed, 01 Jan 2020 00:00:00 GMT

Stress evolution of thin film RuO₂ Li-ion battery electrodes Mills, Brian(Brian A.) Abstract Thin Film Li-ion batteries (TFB) are seen as a promising candidate for powering small, low power microelectronic devices as they exhibit high energy density and can operate reliably at low voltages. Currently the biggest obstacle to TFB battery development is high volume expansion and material degradation in electrodes with high theoretical Li ion capacities. Among these materials is RuO₂, which exhibits excellent capacity and great potential for use as either cathode or anode in low power electronics. In order to better understand the mechanisms that underlie mechanical failure in RuO₂, we perform the first in situ measurement of mechanical stress evolution in thin film RuO₂ electrodes. The results of these measurement reveal a very unique stress evolution pattern in RuO₂, which has not been observed or modeled in any previous experiment, exhibiting near zero stress delithiation and linear increase in stress during lithiation. These results point to a mode of failure of RuO₂ which does not occur in other materials currently being studied. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 35-39).

Sensitivity Models for [Beta]+/EC Discovery in Large-Volume Scintillation Detectors

Wed, 01 Jan 2020 00:00:00 GMT

Sensitivity Models for [Beta]+/EC Discovery in Large-Volume Scintillation Detectors Graham, Eleanor(Eleanor L.) In this thesis, we consider the [Beta]+/EC decay of 124Xe and take the first steps towards characterizing a hypothetical experiment to detect it, making use of techniques traditionally employed in neutrinoless double beta decay experiments. We use a simulated large-volume scintillation detector modeled on the Super-Kamiokande experiment, fully implementing this detector in RAT/Geant4. This allows us to extract authentic spectra for the experimental signature of the [Beta]+/EC decay in 124Xe, paving the way for future sensitivity studies. We also consider the relevance of next-generation techniques for background discrimination, specifically particle identification based on counting Cherenkov photons. We find that discrimination between [Beta] and [Beta] particles is readily possible in experiments run at the 1.25 MeV energy scale and also see evidence for the possibility of distinguishing between [Beta]+ and [Beta]- particles via their Cherenkov signatures Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2020; In title on title page, "[Beta]" is the Greek letter. Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 47-49).

Investigation of non-normal incidence charged-particle response of CR39 nuclear track detectors, with applications in nuclear diagnostics for inertial confinement fusion

Wed, 01 Jan 2020 00:00:00 GMT

Investigation of non-normal incidence charged-particle response of CR39 nuclear track detectors, with applications in nuclear diagnostics for inertial confinement fusion Przybocki, Ryan. CR39 is a plastic nuclear track detector used at inertial confinement fusion (ICF) facilities to characterize the energy spectra of fusion products. This thesis presents data collected at MIT's Linear Electrostatic Ion Accelerator (LEIA) to measure CR39's detection efficiency for protons at non-normal incidence to CR39 detectors. We specifically study protons resulting from D-D fusion reactions with incident angles up to 50 degrees. Understanding the CR39 response to charged particles at an angle is essential to designing a D-D neutron spectrometer at the Z facility, which uses CR39 to detect protons incident at an angle. We find that small adjustments of 10 degrees have no effect on detection efficiency, and high detection efficiency is preserved up through 25 degrees in the range of 1.0 to 2.1 MeV. For the ICF applications, incident angles above 30 degrees are generally impractical for spectrometer design due to significant drops in proton detection. We compare the experimental results to related theoretical simulations, proposing significant constraints on these theoretical models of detection efficiency. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 44-45).

Probing electron-electron and electron-phonon interactions in twisted bilayer graphene

Wed, 01 Jan 2020 00:00:00 GMT

Probing electron-electron and electron-phonon interactions in twisted bilayer graphene Phinney, Isabelle Y. Two-dimensional systems, and, most recently, moire systems, have risen to the forefront of condensed matter physics with the advent of experimental techniques that allow for controlled stacking of van der Waals heterostructures [17, 54]. For example, it was recently discovered that when two pieces of atomically thin carbon (graphene) are twisted at 1.1° with respect to one another, they display a variety of effects, including superconducting behavior [10]. Experimental investigation of the behavior of small-angle twisted bilayer graphene (SA-TBG) as a function of twist angle is imperative to understanding the mechanisms that play into the many interesting, strongly-interacting phenomena that the moire system displays. In this thesis, I present three experiments which explore electron-electron and electron-phonon interactions in SA-TBG. I first consider SA-TBG as a host for a viscous electron fluid and look for the onset of fluid behavior via electron transport. Then I investigate the temperature dependence of resistivity in SA-TBG devices at a number of angles. The final experiment examines magnetophonons in three devices above the magic angle and compares the findings to theoretical results. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 81-86).

Supersymmetry, supergravity, and String Theory based inflationary cosmology

Wed, 01 Jan 2020 00:00:00 GMT

Supersymmetry, supergravity, and String Theory based inflationary cosmology Kraj, Megan C. The aim of this thesis is to investigate and present an overview of inflationary theory. As part of this effort, the main motivations for cosmic inflation, which are known as problems in the standard big bang scenario, are reviewed. These problems are the "flatness problem", "horizon problem", and the "monopole problem." Analysis of inflation caused by a single scalar field rolling on a scalar potential is considered. This enables the introduction of the "slow-roll parameters" and their application. Since supersymmetry is considered a candidate beyond the standard model theory, we explore the connection between supersymmetry and the early universe. In order to incorporate gravity at energy scales of the early universe, supergravity is examined as well. Having considered inflation in the context of supersymmetry and supergravity, it is therefore natural to present the role of string theory in inflationary model building. As a result, axion monodromy is considered. Representative models are compared to analysis of precision measurements of the cosmic microwave background radiation. This comparison is achieved using observable derived constraints of the spectral index and tensor to scalar ratio. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 150-151).

Implementation of the Fizeau aether drag experiment for an Undergraduate Physics Laboratory

Wed, 01 Jan 2020 00:00:00 GMT

Implementation of the Fizeau aether drag experiment for an Undergraduate Physics Laboratory Trbalic, Bahrudin. This work presents the description and implementation of the historically significant Fizeau aether drag experiment in an undergraduate physics laboratory setting. The implementation is optimized to be inexpensive and reproducible in laboratories that aim to educate students in experimental physics. A detailed list of materials, experimental setup, and procedures is given. Additionally, a laboratory manual, preparatory materials, and solutions are included.. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (page 69).

Low noise magnetic fields in ultracold experiment

Wed, 01 Jan 2020 00:00:00 GMT

Low noise magnetic fields in ultracold experiment Nolasco-Martinez, Eber. Ultracold atomic and molecular experiments rely on low noise ambient magnetic fields for precision spectroscopy and studying Feshbach resonances with narrow linewidths, which can be on the order of 1 [mu] T. The ambient field is impacted by both the Earth's magnetic field and technical noise from surrounding electrical equipment, which can vary through the day. We built an apparatus using an Arduino microprocessor to record the ambient fields with magnetometers located outside the vacuum chamber containing the atoms and output transformed waveforms at 30 Hz intervals to be feed forwarded to the coils and cancel both the average field and fluctuations. We achieved an RMS of 37 nT along one axis in the magnetic fields in our test setup using this apparatus, reducing the 60 Hz component by 30 dB and the 180 Hz component by 20 dB. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 54-55).

Electronics first : development of a basic electronics course of study for naval engineers

Wed, 01 Jan 2020 00:00:00 GMT

Electronics first : development of a basic electronics course of study for naval engineers Ruggles, Tikhon(Tikhon James) MIT's 2N program produces naval engineers for the U.S. Navy. It provides its students with a solid foundation of critical engineering, design, construction, and naval architecture concepts. However, within that curriculum, there is less of an emphasis on electrical engineering and electronics as it applies to shipboard systems. The purpose of this project is to outline a new course of study centered around laboratory assignments designed especially for the 2N program that will provide an accelerated introduction to electronics and electrical engineering for the naval engineer. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Thesis: S.M. in Naval Architecture and Marine Engineering, Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 109-110).

Incorporating contact management and marine dynamics in decentralized auction bidding for autonomous surface vehicles

Wed, 01 Jan 2020 00:00:00 GMT

Incorporating contact management and marine dynamics in decentralized auction bidding for autonomous surface vehicles Stanfield, Brian(Brian Asunuma) This research studies techniques that can be applied to practical multi-task multi-vessel marine applications to manage mission planning for autonomous surface vehicles (ASVs). This thesis investigated the use of a decentralized Consensus Based Auction Algorithm (CBAA) for marine autonomous vehicles while incorporating contact management and marine vehicular dynamics [1]. CBAA is a task allocation system that does not require a central agency. The task investigated in this thesis is to transit to a waypoint in a dynamic environment, including other moving vessels to avoid. To reach the goal of this thesis, this methodology is implemented to assign a value to an auction bid given the contact environment and vehicle dynamics. The Mission Oriented Operating Suite with Interval Programming (MOOS-IvP) was utilized to demonstrate this capability and finally, this work provides an analysis of MOOS-IvP simulated data runs utilizing contact management and vehicular dynamics. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 53-54).

The design, feasibility and cost analysis of sea barrier systems in Norfolk, Virginia and the comparative cost of shoreline barriers

Wed, 01 Jan 2020 00:00:00 GMT

The design, feasibility and cost analysis of sea barrier systems in Norfolk, Virginia and the comparative cost of shoreline barriers Hasenbank, Charles H.(Charles Hayden) Protecting a coastline from the damage of a storm surge, or tidal flooding associated with sea level rise, is a challenging and costly engineering endeavor. Low lying properties located directly on an ocean coastline are limited in protective solutions to include constructing shoreline barriers, increasing building elevations, or relocation. However, shoreline properties on an estuary are afforded the additional protective option of a dynamic sea barrier spanning the mouth of the bay or river. The Delta Works projects in the Netherlands pioneered the design and construction of large scale dynamic sea barriers. Although similar projects have been built or proposed, the high costs have minimized wide spread implementation. Even with positive benefit-cost ratios of prevented property damage to sea barrier cost, the willingness to fund these multi-billion dollar projects is reduced when the probability of extreme coastal flooding is associated with 100 to 1000 year storms. However, if sea level rise shifts the flooding probability to include king tides and annual storms, the perspective regarding the relative cost of a sea barrier system may soon change. This study serves as a design, feasibility and cost analysis of potential sea barrier systems in the Chesapeake Bay near Norfolk, Virginia. Several sea barrier concept designs were proposed, and analyzed against intermediate sea level rise scenarios for the year 2100, to determine feasibility based on topography and projected tide levels. The cost and performance of the design concepts were then examined to determine an optimal design. Finally, the cost of the optimal sea barrier system was compared to the notional cost of installing shoreline barriers along the extent of the estuary, to determine the most cost effective method of coastal flooding protection. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 157-159).

Beamforming performance enhancement by adaptive hyperbola array shape estimation

Wed, 01 Jan 2020 00:00:00 GMT

Beamforming performance enhancement by adaptive hyperbola array shape estimation Liu, Michael Kaiping. Analysis of U.S. Navy Ice Exercise 2016 (ICEX16) data, through a collaboration with MIT Lincoln Laboratory, demonstrated that towed array curvature commonly exhibited heading differences up to 100° and never maintained heading differences less than 30° between the forward compass and the aft compass. These deviations reflected a disparity from the underlying assumption that the towed array remained rigid with no deviations from a rigid, straight-line configuration. Using lessons learned from ICEX16, a field experiment in Massachusetts Bay 2019 (FEX19) tested whether a hexagonal search pattern would sufficiently address the curvature concern, thereby, validate the underlying rigid, straight-line beamformer assumption more commonly used. Results from the experiment showed that a hexagonal search pattern maintained a heading differences of less than 4° within 79 seconds of an initiation of a 60° maneuver.; This was a marked improvement when compared to ICEX16's vehicle maneuvers, which never maintained a heading difference of less than 30°. Even with this improvement in FEX19, 39.6% of the acoustic data was collected when the towed array did not meet the straight-line assumption. Use of the hexagonal search pattern, in two instances during U.S. Navy Ice Exercise 2020 (ICEX20), showed that 45.1% and 27.1% of the collected acoustic data did not meet the towed-array straight-line assumption. Although this realization will influence operators to minimize maneuvers that introduce significant deviations from the underlying beamforming model, field experiments often call for sharper maneuvers. This realization spurred the development of a beamformer that modeled towed array curvature using headings, effectively tangential slopes, at either end of the hydrophone portion of the towed array with a known fixed length to predict how the towed array bends.; Analysis of FEX19 showed that the hyperbola-shaped beamformer output aligned to GPS heading data over 30% of the experimental window compared to less than 10% for the straight-line beamformer. This improvement held true even when the towed array had little or no curvature. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, System Design and Management Program, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 107-112).

Design, construction, and analysis of a modular ship model and open-source autonomous surface vehicle

Wed, 01 Jan 2020 00:00:00 GMT

Design, construction, and analysis of a modular ship model and open-source autonomous surface vehicle Jolley, Austin(Austin Robert) Existing models used to explore hydrostatic, hydrodynamic, seakeeping, and maneuvering characteristics of ships are limited in that their characteristics are essentially static. The effects of various hull appendages, propulsion configurations, and bow and stern designs are difficult to quantify without procuring, instrumenting, and testing entirely new hullform models. Additionally, the realm of marine autonomy has opened up new avenues for exploration in naval architecture which favor endurance and economy over more traditional design goals of speed and capacity. This creates a need for a framework to rapidly design and prototype unmanned surface vessels. This thesis explores the design, manufacture, and analysis of an additively manufactured modular ship model. This model allows for easily altering the shape of the bow and/or stern and it can be lengthened or shortened by the addition or removal of parallel midbody modules. Other designed modules allow the model to be connected to a towing carriage for captive model testing, or be powered and controlled remotely or autonomously for free-running model testing or use as a small Autonomous Surface Vehicle. Analysis of various combinations of these modules was conducted and the results are presented. Additionally, select experiments and design analyses have been developed for educational use as laboratory experiments or academic projects with the goal of furthering the teaching of naval architecture and marine engineering. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 79-80).

Automated decision making for operations within a Traffic Separation Scheme using MOOS-IvP

Wed, 01 Jan 2020 00:00:00 GMT

Automated decision making for operations within a Traffic Separation Scheme using MOOS-IvP Barker, Jason(Jason Barnell) This thesis proposes a set of practical applications that utilizes the sharing of intent information and intended courses between marine vehicles operating in the vicinity of a Traffic Separation Scheme in order to reduce risk of collision for vehicles with intentions to join in accordance with Rule 10 of the COLREGs. The proposed set of applications also creates a method to digitally represent a Traffic Separation Scheme in MOOS-IvP simulation software using a structure modeled after Title 33 of the Code of Federal Regulations. Two types of Traffic Separation Scheme intents are communicated: traffic lane compliance, in which the vessel in the traffic lane is within the lane and on a compliant vessel heading in accordance with Rule 10.b, and compliant lane approach/traffic crossing, in which vehicles with lane crossing intent or intent to enter are on a compliant heading in accordance with Rule 10.c. Incorporating inter-vehicle communications to share intended courses allows for discrete extrapolation of future positions, determination of risk conditions, and ultimately a recommendation for an early speed maneuver to reduce risk conditions. Communications between shore and vehicle are also used to allow the vehicle to populate a Traffic Separation Scheme instance onboard which will enable future flexibility and minimize pre-loading of data for harbor operations. Simulation experiments demonstrate the feasibility of the proposed Rule 10 method in terms of both vehicle safety and proper traffic lane operation. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 97-99).

Toward robust active semantic SLAM via Max-Mixtures

Wed, 01 Jan 2020 00:00:00 GMT

Toward robust active semantic SLAM via Max-Mixtures Baxter, David P.,Nav. E.(David Paul)Massachusetts Institute of Technology. In a step towards the level of autonomy seen in humans, this work attempts to emulate a high level and low level approach to world representation and short term adaptation. Specifically, this work demonstrates an implementation of robotic perception that transforms stereo camera and LIDAR sensor data into a sparse map of semantic objects and a locally consistent flexible occupancy grid. This provides a topological representation for grouping objects into higher level classes and a geometric map for traditional planning. Additionally, a reactive dynamic window obstacle avoidance system is shown to quickly plan short term trajectories that avoid both static and dynamic objects while progressing towards a goal. To combine computational efficiency with the robust advantages of multimodal inference, this work uses Semantic Max Mixture factors to approximate multimodal belief in a manner compatible to nonlinear least squares solvers. Experimental results are presented using a RACECAR mobile robot operating in several hallways of MIT, using AprilTags as surrogates for objects in the Semantic Max Mixtures Algorithm. Future work will seek to further integrate the components to create a closed-loop active semantic navigation and mapping algorithm. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 75-78).

Creating a shipboard power simulation tool using electrical load behavior modeling

Wed, 01 Jan 2020 00:00:00 GMT

Creating a shipboard power simulation tool using electrical load behavior modeling Deeter, Thomas,Lieutenant(Thomas Andrew) Trends in power system simulation that demand computationally-intensive, physics-based models may impede the acquisition of useful results for applications like condition-based maintenance [1], electrical plant load analysis (EPLA) [2], and the scheduling and tasking of finite generation and distribution resources. A tool that can quickly evaluate many scenarios, as opposed to intense, high fidelity modeling of a single operating scenario, may best serve these applications. This thesis presents a behavioral simulator that can quickly emulate the operation of a relatively large collection of electrical loads, providing "what-if" evaluations for more complete exploration of a design or plant operating envelope. Comparisons to field data collected from a microgrid on-board a 270 foot US Coast Guard "Famous" Class medium endurance cutter demonstrate the utility of this tool and approach. The usefulness of this tool is further demonstrated by showing simulated EPLA load factors within 10%of observed load factors over comparable mission sets, both inport and underway. Finally, this thesis will discuss the lessons learned during SPS development and testing, specifically, the need to expand its modeling capability so it can support direct current (DC) electrical distribution systems. The SPS, in its current form can only model alternating (AC) electrical distribution systems. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020; Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, System Design and Management Program, May, 2020; Cataloged from the official PDF of thesis.; Includes bibliographical references (pages 625-626).

The M. I. T. linear accelerator as a pulsed neutron source for a time-of-flight neutron spectrometer

Mon, 01 Jan 1951 00:00:00 GMT

The M. I. T. linear accelerator as a pulsed neutron source for a time-of-flight neutron spectrometer Burkhardt, James Lee.; Fox, John D. 1929- Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Physics, 1951.; Bibliography: leaf 27.

Basic factors affecting smooth engine idling

Wed, 01 Jan 1958 00:00:00 GMT

Basic factors affecting smooth engine idling Rosen, Arthur S. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1958.

Heat requirement for chemically self-heating containers

Thu, 01 Jan 1976 00:00:00 GMT

Heat requirement for chemically self-heating containers Adolph, Gerald Stephen. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1976.; Includes bibliographical references (leaf 28).

An investigation of the properties of protective paints as a coating for masonry and wood surfaces

Wed, 01 Jan 1958 00:00:00 GMT

An investigation of the properties of protective paints as a coating for masonry and wood surfaces Hazan, Robert A.; File, Richard P. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1958.; Includes bibliographical references (leaf 30).

Feasibility of constructing minimum houses (small) using stabilized soils

Wed, 01 Jan 1958 00:00:00 GMT

Feasibility of constructing minimum houses (small) using stabilized soils Carroll Carazo, Victor W. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Civil and Sanitary Engineering, 1958.; Includes bibliographical references (leaves 56-57).

Two undecidability results in probabilistic automata theory

Tue, 01 Jan 1985 00:00:00 GMT

Two undecidability results in probabilistic automata theory Kilian, Joe. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1985.; Bibliography: leaf 13.

A study and implementation of real-time Pascal on the LSI-11

Sun, 01 Jan 1984 00:00:00 GMT

A study and implementation of real-time Pascal on the LSI-11 Hsy, Joe Pei-Wen. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1984.; Includes bibliographical references.

Re-strengthening demineralized bone via tannin-iron crosslinking

Tue, 01 Jan 2019 00:00:00 GMT

Re-strengthening demineralized bone via tannin-iron crosslinking Hart, Sawyer(Sawyer H.) As the world population continues to age, the social and economic impacts resulting from osteoporosis will continue to rise. New treatments for the disease are needed now more than ever. Using tannin iron complexes we show that thin film deposition of the complexes are not only possible but effective at strengthening demineralized bone. Furthermore we show that by taking advantage of newly discovered tris-complexes that are able to form between tannic acid and ferrous iron ion in solution, the strengthening ability of the film increases dramatically. Specifically, we show that tannin iron tris-complex coating results in a 1062% increase in the flexural modulus for fully hydrated and demineralized bone. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages [30]-[31]).

Restructuring the Israeli-Palestinian Joint Water Committee

Tue, 01 Jan 2019 00:00:00 GMT

Restructuring the Israeli-Palestinian Joint Water Committee Schwind, Kathleen K. How can the Israeli-Palestinian Joint Water Committee (JWC) be restructured as a problem-solving entity and how can this newly structured JWC contribute to mutual water security in the region? While the Israel-Palestine conflict remains unresolved, thousands in the region lack a reliable water source. Climate change continues to exacerbate water scarcity, while new technologies like desalination are changing the nature of the relationship between the two parties. Overall, though, there is a deeply rooted sense of distrust between the parties, and political tensions have stalled fruitful water collaboration in recent years. Oslo II called for the creation of the Israel-Palestine JWC in 1995, but since then joint-efforts have had limited success. For over half a decade there were no formal meetings due to political tensions.; Through a review of the literature, a case comparison with the Israel-Jordan water agreement and subsequent JWC, and interviews with leading Israeli, Palestinian, Jordanian, and American water diplomacy experts, hydrologists, professors and past JWC members, I draw five prescriptive conclusions regarding the best ways to restructure the Israeli-Palestinian JWC. First, the JWC needs to adopt a long-term perspective and allow itself to evolve over time, rather than expecting to create a committee with an unchanging structure. In doing so, it should establish a mutually agreed upon conflict resolution and joint-fact finding mechanism, to ensure equal power dynamics between the parties. Second, technical decision-making should be given a larger role to the JWC.; Third, the JWC should shift from a model based on confidentiality to one based on transparency, becoming more transparent as outsiders (the public, respective governments, international community) start building more faith in the JWC's ability to make positive and tangible change. Fourth, the JWC should seek international support to help financially implement joint-projects outlined by the technical subcommittees under the JWC. Lastly, the JWC should work on reframing water in terms of "water security" not "national security." A restructured Israeli-Palestinian JWC could help facilitate collaboration towards actually discussing and carrying out joint-water research and projects, and rekindle trust between the water negotiators and experts on both sides. It cannot be said for certain that water will be an immediate stepping stone towards overall peace in the region.; But water is a worthy first step: Israelis and Palestinians should work together to mutually achieve water security, building some amount of trust along the way, and demonstrate that the two sides can work together to provide their people with the water they need without compromising each sides most important interests. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: M.C.P. and S.B., Massachusetts Institute of Technology, Department of Urban Studies and Planning, 2019; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 156-164).

Renovation & Relocation : MIT Undergraduate Residences : How could MIT house students during the renovations of undergraduate residences in order to mitigate the negative impacts of displacement?

Tue, 01 Jan 2019 00:00:00 GMT

Renovation & Relocation : MIT Undergraduate Residences : How could MIT house students during the renovations of undergraduate residences in order to mitigate the negative impacts of displacement? Edgar, Sarah H. As MIT renovates many of its undergraduate dormitories, special attention must be paid to the fate of displaced students and communities. This thesis examines the context that necessitates renewal processes on college campuses and at MIT specifically. It connects the issue to existing displacement research from urban renewal and gentrification, as well as theories of practice for participatory planning processes. Much of the research involves interviews held with students from communities that have been displaced by recent emergencies and renovations as well as communities in buildings that are slated for future renovation. The key findings are used to form a number of recommendations for best practices in future planned displacements at MIT. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B. in Planning, Massachusetts Institute of Technology, Department of Urban Studies and Planning, 2019; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 85-86).

A study of the relationship between micropulsations and solar wind properties

Sun, 01 Jan 1989 00:00:00 GMT

A study of the relationship between micropulsations and solar wind properties Yedidia, Barak A. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1989.; Includes bibliographical references (leaf 18).

Interaction design and healthcare : a mobile experience for engaging with personal health records

Tue, 01 Jan 2019 00:00:00 GMT

Interaction design and healthcare : a mobile experience for engaging with personal health records Liu, Cindy Rae. One of the innate challenges of primary healthcare is the transfer of information from expert to patient, the root of a myriad of problems relating to medical noncompliance and suboptimal care. The constant challenge for patients to understand and act on the medical data they receive brings to light an issue entangling communication and human behavior. Especially as modern technology makes data increasingly accessible, it is more important than ever to ensure that this information is being presented effectively and serves the fundamental purpose of informing and educating patients for their well-being. In recent years, a digital health movement has made common a variety of electronic platforms, such as patient portals and apps, aiming to enhance the healthcare experience. However, most of these platforms focus on digitizing and increasing access to care rather than actually helping patients understand their health data and its implications. Additionally, studies on current systems emphasize a lack of user-friendliness and failure to adopt (nearly 80% of mobile applications are abandoned after two weeks). Furthermore, these platforms can distance patient from physician and lack reliable follow-up methods. This thesis proposes a unique mobile web experience that addresses current gaps and refocuses on the fundamental user needs of the patient from an interaction design perspective. I specifically narrow in on the common experience of receiving lab test results from a routine check-up. Based on user research and design principles, this concept aims to help patients better consume, comprehend, and activate on their health data, as a demonstration of the increasing value of design in the industry and in an increasingly digital world. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B. in Art and Design, Massachusetts Institute of Technology, Department of Architecture, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 34).

A study on the post-graduate outcomes of mechanical engineering undergraduate students at MIT

Tue, 01 Jan 2019 00:00:00 GMT

A study on the post-graduate outcomes of mechanical engineering undergraduate students at MIT Yang, Illina(Illina Y.) This study investigates the immediate post-graduation outcomes of undergraduate students from the Massachusetts Institute of Technology with a focus on those from the Course 2 (Mechanical Engineering) department. Outcomes for students graduating between the years of 2006 through 2018 were analyzed, including salaries, industries, and companies for students following their graduation. The majority of students chose to either attend graduate school or work in industry immediately after receiving their undergraduate degree. Of those who chose to work, most start in roles related to their major in Computer/Engineering/Technology or in Consulting/Finance industries. The For Course 2 students, a large number also went to companies working in the Aerospace/Automotive/Energy sector. The salaries for MIT undergraduates has increased steadily over the years. This study also identified gaps in current research and knowledge and presents questions to guide future studies on post-graduation outcomes of MIT students. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 45).

Design of sensor system to monitor napkin usage for sustainable user behavior

Tue, 01 Jan 2019 00:00:00 GMT

Design of sensor system to monitor napkin usage for sustainable user behavior Yan, Toria F.(Toria Faye) This paper discusses the process of designing and integrating a sensor that is able to detect each individual napkin removed from a napkin dispenser to aid in long term data-collection with the implementation of eco-feedback designs. With the implementation of this sensor, we would be able to evaluate the effects of various design for sustainable behavior strategies and their influence on user sustainable behavior. To create this measurement method, multiple sensor types were tested for accuracy, sensitivity, and other features before down-selecting and integrating into a final sensor design. It was determined that the use of limit switch sensors connected by a lever could be used to collect more accurate results than the current method of hand measuring inventory or taking an approximate measurement of the height of total napkins remaining. Our results were promising, as we were able to successfully trigger our sensor once at almost every instance of napkin removal as well as solve our battery capacity issue. The main task that still needs to be tweaked are the edge cases, specifically the notorious case in which one napkin is removed at a slow speed, causing bouncing and multiple triggers to occur. With this sensor in place, we will be able to collect more accurate data and better analyze the effects of positive information, negative information, and feedback designs in napkin dispensers on long term user interaction. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 39).

Compression model on a clinically-relevant in-vitro lactating breast model

Tue, 01 Jan 2019 00:00:00 GMT

Compression model on a clinically-relevant in-vitro lactating breast model Xi, Tiffany(Tiffany Jane) Breastfeeding is incredibly important in infant nutrition and can provide many health benefits for the lactating parent as well [1]. Breast pumps allow for the expression and feeding of breastmilk when natural breastfeeding cannot occur. However, breast pumps only use suction to express milk, and the mechanics that come from a baby's natural suckling [2] are ignored. The aim of the research in this thesis is to understand the capabilities of compression via soft robotics in assisting the expression of milk from a lactating breast. The work presented in this thesis is two-fold: (1) a clinically-relevant in-vitro model of the lactating breast is developed, and (2) a soft robotic compression model mimicking natural breastfeeding and hand expression is tested on the lactating breast model. Although the compression model alone was able to express liquid from the model, it was not as effective as suction alone, nor did it increase the efficacy of suction when used in conj unction. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 21-22).

The effects of different quenching mediums on the hardness and microstructures of steel

Tue, 01 Jan 2019 00:00:00 GMT

The effects of different quenching mediums on the hardness and microstructures of steel Peinado Estrada, Ruben. The rate of heat extraction, hardness, and severity of quenching steel has been investigated using conventional and nonconventional methods. A variety of steel alloys such as 4140, D2, S7, and O1 were used in the preliminary tests with conventional quenching methods to observe the microstructures and hardness development. Results showed that as the cooling rate of the steel increase, the hardness of the steel increased. The microstructure of the conventional quenching methods were similar throughout the metal samples; air quenching produced larger grains of pearlite, ferrite, and cementite, oil quenching produced martensite and pearlite grains, and water quenching produced martensite. Afterwards, a further study was done with unconventional quenching methods on 1045 steel. The unconventional quenching methods that were studied included Olive Oil, Peanut Oil, Quench Fast, and Super Quench, quenchants which have been proliferated through blogs, online forums, and discussion boards.; The results have shown that the unconventional quenching produces hardnesses greater than control samples. The quenching methods, however, within the range of 50 Vickers Hardness of each other, which is a small difference. Super Quench and water quench samples are within the standard deviation of their samples set from the hardness of each other similarly to Olive Oil and Quench Fast. Additionally the two groups of similar hardness had similar microstructures being composed of mainly martensite. It could be concluded that water and Olive Oil have the same effects as Super Quench and Quench Fast on 1045 steel respectively; therefore water and olive oil can be used as substitution providing a solution that are sustainable, nontoxic and quick to prepare. The metallurgical community has proliferated the use of unconventional quenching media as methods to yield superior results in steels.; However, the results in this work show that the usage of different media rather than conventional quenching media, produce hardness and microstructures that are similar in value and composition. Therefore, there is no advantage to using quenching methods that have been advertised through blogs, online forums, and discussion boards. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 35).

Efficacy of inertial measurment units in the analysis of swim technique

Tue, 01 Jan 2019 00:00:00 GMT

Efficacy of inertial measurment units in the analysis of swim technique Kelsall, Nora Clancy. This experimental study explored the efficacy of inertial measurment units (IMUs) in the analysis of swim technique. A BNO055 IMU was used to record linear acceleration for three different scenarios: normal stroke technique, straight arm swimming, and swimming while crossing the midline. Video recordings from front and side angles were taken for comparison, as video analysis is the gold standard for technique assessment. Acceleration data was used to create a model of a normal stroke in the x,y, and z directions. The model was compared against samples of each type of technique disturbance. Analysis of fit to the model showed that while the average distance from the model for the straight arm technique was higher, the cross over stroke had similar deviation from the model as the normal stroke samples. This result suggests that this method of analysis makes characterization of technique difficult, although it remains a promising field for continued study. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 29).

Viability of Ion Concentration Polarization technology for creation of a portable desalination Unit

Tue, 01 Jan 2019 00:00:00 GMT

Viability of Ion Concentration Polarization technology for creation of a portable desalination Unit D'Alessandro, Alexis(Alexis M.) Ion Concentration Polarization (ICP) is an emerging desalination technology developed by the Han Group of MIT Research Laboratory of Electronics. ICP desalination has significant benefits over conventional desalination technologies, and subsequently, may be well equipped for the creation of a portable desalination unit. Portable desalination units have applications in disaster relief and providing drinking water to remote regions of developing nations without established water infrastructure. In this thesis, the viability of a portable desalination unit based upon ICP is assessed. A number of different system modifications, both theoretical and experimental, are proposed to increase the propensity of ICP to meet the needs of such a portable system. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis. "June 2019."; Includes bibliographical references (pages 45-47).

Effect of self-irradiation damage on thermal diffusivity and SAW speed in a thorium-doped lead sulfide thin film

Tue, 01 Jan 2019 00:00:00 GMT

Effect of self-irradiation damage on thermal diffusivity and SAW speed in a thorium-doped lead sulfide thin film Sergheyev, Keldin Nehmovitch. Lead sulfide (PbS) is an important semiconductor for infrared light detection, and use in space necessitates understanding how it evolves when damaged by ionizing radiation. Previous work in chemical bath deposition (CBD) resulted in thin films of epitaxially grown polycrystalline PbS uniformly doped with radioactive thorium 228 (Th-228), permitting convenient study of a self-irradiating sample. This thesis represents a continuation of that work by studying the evolution of thermal diffusivity and surface acoustic wave (SAW) speed in a self-irradiating PbS thin film using the non-contact, non-destructive transient grating spectroscopy (TGS) assay. Radiation damage is allowed to accumulate and TGS is used to take measurements before and after annealing. Damage was presumed to create new phonon-scattering defects, thus decreasing SAW speed and thermal diffusivity. However, after annealing, radiation damage caused a monotonic increase in both. Both parameters asymptotically approach a maximum, which indicates a radiation damage saturation point. Thermal diffusivity does not return to its pre-annealed value, indicating an unknown affect. A longer TGS study is recommended to eliminate latent effects, as well as a band gap time-evolution study and an x-ray diffraction study. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 41-43).

Bound states of pseudo-Dirac dark matter

Tue, 01 Jan 2019 00:00:00 GMT

Bound states of pseudo-Dirac dark matter Bhattacharya, Arindam(Arindam A.) We study the bound-state spectrum in a simple model of pseudo-Dirac dark matter, and examine how the rate of bound-state formation through radiative capture compares to Sommerfeld-enhanced annihilation. We use this model as an example to delineate the new features induced by the presence of a mass splitting between the dark matter and a nearly-degenerate partner, compared to the case where only a single dark-matter-like state is present. We provide a simple analytic prescription for estimating the spectrum of bound states in systems containing a mass splitting, which in turn allows characterization of the resonances due to near-zero-energy bound states, and validate this estimate both for pseudo-Dirac dark matter and for the more complex case of wino dark matter. We demonstrate that for pseudo-Dirac dark matter the capture rate into deeply bound states is, to a good approximation, simply related to the Sommerfeld enhancement factor. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 63-67).

Soft X-ray ptychographic reconstructions of a neodymium nickel oxide thin film

Tue, 01 Jan 2019 00:00:00 GMT

Soft X-ray ptychographic reconstructions of a neodymium nickel oxide thin film Cain, Madelyn(Madelyn G.) Rare earth (R) perovskite nickelates RNiO 3 have a rich phase diagram which includes a metal-insulator and paramagnetic-antiferromagnetic phase transition. In neodymium nickel oxide (NdNiO 3 ), these phase transitions coincide, creating a mixedphase state at the critical point. Imaging these competing phases on a nanometerscale may offer unique insights to the driving mechanism behind the metal-insulator transition, which is not well understood. A combination of soft X-ray ptychography and resonant soft X-ray scattering techniques enable direct imaging of the antiferromagnetic domains of NdNiO 3 at the phase transition. In this thesis, I will present ptychographic reconstructions of an epitaxial NdNiO 3 sample near the critical temperature using data taken at the Coherent Soft X-ray Scattering beamline of the National Synchrotron Light Source II. I used phase retrieval algorithms to reconstruct an image of the sample using the custom-developed software package CDTools, which I helped design and build. My reconstructions reveal the antiferromagnetic domains of NdNiO 3 near the critical point, paving the way for future reconstructions of quantum materials. I address several factors limiting the quality of the reconstructions, including uncertainties in the location of the nanopositioners and the beam energy. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 67-69).

Ultracold neutron storage simulation using the Kassiopeia software package

Tue, 01 Jan 2019 00:00:00 GMT

Ultracold neutron storage simulation using the Kassiopeia software package Bogorad, Zachary. The Kassiopeia software package was originally developed to simulate electromagnetic fields and charged particle trajectories for neutrino mass measurement experiments. Recent additions to Kassiopeia also allow it to simulate neutral particle trajectories in magnetic fields based on their magnetic moments. Two different methods were implemented: an exact method that can work for arbitrary fields and an adiabatic method that is limited to slowly-varying fields but is much faster for large precession frequencies. Additional interactions to simulate reflection of ultracold neutrons from material walls and to allow spin-flip pulses were also added. These tools were used to simulate neutron precession in the Paul Scherrer Institute's neutron electric dipole moment experiment and predict the values of the longitudinal and transverse relaxation times as well as the trapping lifetime. All three parameters are found to closely match the experimentally determined values when simulated with both the exact and adiabatic methods, confirming that Kassiopeia is able to accurately simulate neutral particles. This opens the door for future uses of Kassiopeia to prototype the next generation of atomic traps and ultracold neutron experiments. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 59-62).

Interferometric techniques for detecting axion dark matter

Tue, 01 Jan 2019 00:00:00 GMT

Interferometric techniques for detecting axion dark matter Elwood, Brodi D. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 59-62).

Chemical characteristics of three stellar streams

Tue, 01 Jan 2019 00:00:00 GMT

Chemical characteristics of three stellar streams Gull, Maude. In this thesis, we present high-resolution spectra of stars of three different stellar stream; Helmi debris stream, Helmi trail stream and [omega] Centauri stream. These stars have metallicities ranging from -3.05 < [Fe/HJ < -1.25 and magnitudes ranging from 9 < V < 13.5, thereby classifying them as bright metal-poor stars. We report detailed chemical abundance signatures of light fusion elements and heavy neutron-capture elements. We find that all three streams contain stars with r-process abundance signatures. Additionally, three star show a clear combined r+s-process enhancement. Those stars likely formed from a r-process enhanced gas and then experienced a s-process mass-transfer by a binary companion. Given the occurrence of r-process enhanced stars in all three streams, it is likely that the progenitors of these streams must have been similar in nature to ultra-faint r-process dwarf galaxies like Tucana III and Reticulum II, which were enriched in r-process elements by one neutron star merger or another prolific r-process source at the earliest times. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 37-40).

An optical accordion trap for two-dimensional ultracold gases of ⁶Li and ²³Na

Tue, 01 Jan 2019 00:00:00 GMT

An optical accordion trap for two-dimensional ultracold gases of ⁶Li and ²³Na Kendrick, Lev Haldar. An optical accordion trap is an optical lattice with a variable periodicity. By loading ultracold gases into a node of an accordion trap and then decreasing the lattice spacing, we plan to compress three dimensional ultracold gases of ⁶Li and ²³Na down to two dimensions, to create two-dimensional ultracold Fermi and Bose gases with high atom number. We describe the design, construction, and operation of our accordion trap, and comment on potential future improvements. By enabling the study of two-dimensional ultracold atomic Fermi gases at comparatively high density, our work will help to address contemporary topics in many-body quantum physics, such as two-dimensional fermionic superfluidity and quantum Hall physics. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 79-82).

The hierarchy of excitation lifetimes in two-dimensional Fermi gases

Tue, 01 Jan 2019 00:00:00 GMT

The hierarchy of excitation lifetimes in two-dimensional Fermi gases Ledwith, Patrick John. In this thesis we show that omentum-conserving quasiparticle collisions in two-dimensional Fermi gases give rise to a large family of exceptionally long-lived excitation modes. The lifetimes of these modes exceed by a factor (TF/T)2 >> 1 the conventional Landau Fermi-liquid lifetimes T ~ TF/T2. The long-lived modes have a distinct angular structure, taking the form of cos m6 and sin mO with odd m values for a circular Fermi surface, with relaxation rate dependence on m of the form m4 log m, valid at not-too-large m. In contrast, the even-m harmonics feature conventional lifetimes with a weak m dependence. The long-time dynamics, governed by the long-lived modes, takes the form of angular (super)diffusion over the Fermi surface. Altogether, this leads to unusual long-time memory effects, defining an intriguing transport regime that lies between the conventional ballistic and hydrodynamic regimes. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 79-81).

Analyzing CMS open collider data through topic modeling

Tue, 01 Jan 2019 00:00:00 GMT

Analyzing CMS open collider data through topic modeling Mastandrea, Radha. We conduct an investigation of jet substructure at the Large Hadron Collider (LHC) on the CMS Open Data. We analyze a sample of jets detected by the CMS experiment in 2011 with the companion simulated (both pre- and post-detector) jet datasets to demonstrate the ability of our analysis framework to accurately quantify jet substructure observables as well as properly describe the effects of the CMS detector. We move to a specific analysis of jet classification using the unsupervised algorithm of jet topics to provide a new way of defining the categories of quark and gluon jets through their observable properties. We finally outline a means of accessing our sample of 883,431 high quality CMS-detected jets so that other scientists may conduct their own analyses on this sample. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 57-60).

The frequency spectrum of gravitational waves from eccentric orbits

Tue, 01 Jan 2019 00:00:00 GMT

The frequency spectrum of gravitational waves from eccentric orbits Sen, Bidisha. Gravitational waves emitted from binary black hole systems carry energy away from the orbit, and cause the black holes to spiral towards one another and eventually merge. While all such detected systems are effectively circular at coalescence, these binaries may start out with non-negligible eccentricity. Due to certain astrophysical phenomena, it is expected that some binary systems may merge with some residual eccentricity, and so understanding how to measure the waveforms from these systems are of particular interest for future third generation detectors, such as LISA. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 39).

Dynamic line integral convolution for quantum hydrodynamics

Tue, 01 Jan 2019 00:00:00 GMT

Dynamic line integral convolution for quantum hydrodynamics Vo, Ethan(Ethan V.) This thesis demonstrates the application of the dynamic line integral convolution (DLIC) algorithm to the Gross-Pitaevskii equation and quantum hydrodynamics. Line integral convolution is a powerful method of visualizing vector fields, particularly in fluid mechanics and electromagnetism. By assigning specific hues along streamlines of a fluid, line integral convolution helps to visualize flow and understand physical phenomena. This method was applied to a specific quantum state, a squeezed coherent state with Kerr nonlinearity, in order to demonstrate the effectiveness of this method in illustrating the state's quantum hydrodynamical properties. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 39-40).

Measuring coronary artery flow rates using intravascular optical coherence tomography to improve the assessment of percutaneous coronary intervention

Tue, 01 Jan 2019 00:00:00 GMT

Measuring coronary artery flow rates using intravascular optical coherence tomography to improve the assessment of percutaneous coronary intervention Yoon, Ha Yun Anna. In this project, a blood flow quantification technique was developed based on a novel backscattering indicator-dilution approach for intravascular optical coherence tomography (IV-OCT). It achieved the goal of obtaining the flow velocity in a coronary artery of interest by analyzing the backscattering signal from blood after passage of a bolus of Ringer's lactate or another transparent injectate, in parallel to thermodilution coronary flow reserve (CFR). In contrast to thermodilution CFR, the structural OCT image can be used to determine the bolus volume and transit time, as well as used to account for motion and volume change between the two flow readings. More importantly, this technique allows the absolute blood velocities to be determined, providing information that has been challenging to obtain in the past. The experiments conducted using porcine blood in a phantom setup and saline bolus injectate allowed the author to develop an analysis technique to determine transit time, confirming a relation between transit time and flow rate and a relation between the derivative of the transit time and flow rate. Flushing time ([tau]), defined as the time when the normalized flushed area reaches 50%, is inversely proportional to flow rate. Therefore, experimental results validated the feasibility of using OCT to determine transit time of the blood circulation in coronary arteries. Future implication of this experiment is the ability to get more accurate measurement of the blood flow rate at any location regardless of the blood vessel geometry. Findings of this and future experiments can be used to implement intravenous OCT flowmetry for clinical use in diagnosing cardiovascular diseases. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 32-33).

Optomechanical design for CubeSat Laser Infrared CrosslinKs

Tue, 01 Jan 2019 00:00:00 GMT

Optomechanical design for CubeSat Laser Infrared CrosslinKs Yenchesky, Laura K.(Laura Katarina) The CubeSat Laser Infrared CrosslinK (CLICK) mission is a technology demonstrator for a 1.5U intersatellite link laser communications terminal deployed on a pair of 3U CubeSats in Low Earth Orbit (LEO). The narrow transmission full-width half-maximum (FWHM) beamwidth of 14.6 arcseconds coupled with a wider beacon FWHM beamwidth of 0.75 degrees requires precise alignment between and inside both terminals. A two stage pointing, acquisition, and tracking approach is used with a fixed beacon. The coarse pointing stage allocates pointing error to misalignments between the payload aperatures and star tracker aperatures induced by thermoelastic effects. A thermal model, structural model, and statistical analyses are integrated to conclude total thermoelastic induced beacon pointing error with respect to the spacecraft body frame to be less than 9 arcseconds. The ne pointing stage of the approach drives optical mount design with tight tolerances, as well as structural and fastener analysis. Required decentering allowances are as tight as 25.4 [mu]m and 0.1° of allowable rotation from the ideal positions. Kinematic mounts with a translational resolution of ± 15 [mu]m and an angular resolution of ±30 arcsec are implemented at the most sensitive mount locations to enable precision calibration of the payload on the ground. Structural static loading and modal analyses of the CLICK payload under launch loads are conducted to show that the spacecraft bus will not deform sufficiently to cause a beacon pointing loss and that payload elements will not fail under launch loads of 30 G. Margins of safety for static loading in each direction and for fasteners with respect to separation, shear, and tension are greater than 10, above the recommended value of 0. The first resonant frequency of the payload is over 800 Hz, greater than the standard minimum of 100 Hz. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 54-56).

Development of a photolithography procedure for the fabrication of micro-engineered boiling surfaces

Tue, 01 Jan 2019 00:00:00 GMT

Development of a photolithography procedure for the fabrication of micro-engineered boiling surfaces Cassidy, Christopher(Christopher M.) Boiling is a very effective heat removal process, used for heat management in many engineering systems, such as electronic devices or nuclear reactors. However, if the heat flux to remove exceeds the so-called Critical Heat Flux (CHF), the process fails, leading the whole system to failure. A higher CHF is desirable, as it translates into higher power density or, in the case of nuclear reactors, a high power rating. Thus, many researchers are exploring solutions to increase this limit by engineering the boiling surface. However, while promising results have been obtained, the enhancement mechanisms, and how to optimize them, are not clear. The goal of this project was to develop a procedure for fabricating special "research" boiling surfaces to explore these phenomena. These surfaces have well-controlled features. These consist of a layer of copper with star-shaped holes 250 or 500 microns in diameter and 10 microns deep. The steps to create this surface involve photolithography with a positive photoresist, to create the pillars (filled-in holes), and electroplating to build the surface around the pillars. The procedure developed requires a double coat of AZ 9260, exposure, partial development in AZ 435, and re-exposure and developing to achieve the desired thickness. Electroplating at very low current, roughly 0.015 A (3.75 mA/cm2), with minimal stirring, yields a uniform layer of copper. This method will be applied to the fabrication of heaters for boiling experiments. Should these experiments demonstrate a substantial increase in CHF, this procedure could serve as a first step towards applying the technology to industrial surfaces, such as nuclear reactor claddings. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2019; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (page 38).

Characterization of the MIT Graphite Exponential Pile

Tue, 01 Jan 2019 00:00:00 GMT

Characterization of the MIT Graphite Exponential Pile Hauptman, Sara(Sara E.) Subcritical graphite piles were originally built as an important tool for determining diffusion length and criticality in the early days of nuclear engineering. MIT still retains a graphite exponential pile, recently recommissioned back into service, and utilized by students for hands-on demonstration of classroom topics like buckling, subcritical multiplication, and 1 group diffusion. For most effective use, the characteristics of the pile, including flux profile, source-dependence, and fuel slug composition, should be well known. In this thesis neutron radiography was performed on 10 different fuel slugs from the pile to directly measure the thickness of the aluminum cladding and confirm the suspected method of slug fabrication. This sample of fuel slugs had an average clad thickness of 4.66mm±0.03mm on the bottom, 4.10mm±0.02mm on the top, and 1.48mm±0.02mm on the side. Additionally, a detailed neutronic model of the pile was created using MCNP5 software and used to map the spatial source dependence. Experimental measurements were taken to compare to simulated model data and determine the accuracy of the model. The overall flux shapes were similar, but the error between the model prediction and the measured data was greater than 15% for the 6-7 sampling locations that were furthest from the source. The characterization of the slugs and development of a neutronic model will allow for more localized calculations of a wide variety of fuel loading patterns and better utilization of the Pile as a teaching tool.. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2019; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 49-50).

Exploring the improvement of HTGR economics with heat storage for variable electricity output at base-load operations

Tue, 01 Jan 2019 00:00:00 GMT

Exploring the improvement of HTGR economics with heat storage for variable electricity output at base-load operations Inman, Charles T. Nuclear power plants operate most efficiently at a constant power output. This creates problems for nuclear power plants operating in electricity markets with large amounts of non-dispatchable energy generation, where the price of electricity can reach zero as a result of supply overload. Nuclear reactors must sell electricity for extremely low prices or complicate operation by adjusting the output of the reactor core. Heat storage can serve as a solution to this problem by enabling nuclear power plants to store the thermal output of a reactor and convert it to electricity at more profitable times. This study considers multiple design options for a sensible heat storage system with the intent of limiting capital investments required to construct the heat storage system. A novel design based on existing heat recuperator is proposed. This design is integrated into the primary loop of an HTGR reactor to minimize the use of inefficient heat exchangers. The proposed system is connected to the reactor outlet and inlet and operates a separate turbine loop once charged. The heat storage media is chosen to be ceramic brick made of alumina or magnesia, though cast iron and graphite are also considered as candidates. The system is housed in a prestressed concrete pressure vessel with an approximate volume of 25000 - 27000m3. A detailed cost analysis must be performed on this system, or any variation, in order to assess the viability of the design in a market setting. By providing a framework for gigawatt-hour scale thermal storage in nuclear reactors, this thesis aims to prompt a greater design focus on coupling heat storage capacity to nuclear power plants. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 55-57).

Design of the gas-puff imaging diagnostic for Wendelstein 7-X

Tue, 01 Jan 2019 00:00:00 GMT

Design of the gas-puff imaging diagnostic for Wendelstein 7-X Tang, Kevin(Nuclear science engineer)Massachusetts Institute of Technology. Stellarators, being not as well-studied as tokamaks, have plenty of interesting physics to examine, as investigations of stellarators as a viable configuration for future power plants continue. One of these aspects is boundary turbulence in the plasma, as the magnetic configuration in stellarators is different from that in tokamaks and thus provides different plasma behavior. To study this turbulence, we are designing a "gas-puff imaging" diagnostic to install onto the Max Planck Institute of Plasma Physics's Wendelstein 7-X (W7-X), which is currently the world's most advanced and largest stellarator. This diagnostic employs a fast-camera to observe a localized puff of gas as it interacts with the boundary plasma near the last closed flux surface of the plasma. The diagnostic consists of a fast-camera component, a light-collection component, a "gas-puff" component with valves to inject controlled amounts of gas, and a component for valve control and data collection purposes. This thesis documents some of the aspects of the design of the diagnostic and its components for W7-X. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 97).

Machine learning for nuclear fission systems : preliminary investigation of an autonomous control system for the MGEP

Tue, 01 Jan 2019 00:00:00 GMT

Machine learning for nuclear fission systems : preliminary investigation of an autonomous control system for the MGEP Wilson, Jarod(Jarod C.) Commercial nuclear technology today is facing challenges due to both economic viability and concerns over safety. Next-generation reactors could potentially improve with respect to both concerns through recent advancements in computation and machine learning, through autonomous control systems which minimize human error. The MIT Graphite Exponential Pile (MGEP) has been selected as the basis of a realworld demonstration of such a system, because of its simple properties and inherent safety. This study evaluated the preliminary feasibility of an autonomous control system for the MGEP through two parallel avenues; a practical investigation of various machine learning algorithms applied to fission systems, as well as the design and fabrication of a control rod for the pile. It was found that Convolutional Neural Networks (CNNs) outperform Support Vector Regression (SVR) in predicting the MITR power-shape. Additionally, acceptable results were achieved when applying the CNN algorithm to the MGEP to predict the flux distribution of its fuel elements. Finally, it was verified that neutron detectors in the pile respond predictably to control rod insertions. Taken together, the groundwork for the further development of an autonomous control system has been laid, and the path forward is promising. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 69-70).

Search for the production of quark-gluon plasma in e+e- collisions at [square root of] s = 91.2 GeV with Archived ALEPH LEP1 data

Tue, 01 Jan 2019 00:00:00 GMT

Search for the production of quark-gluon plasma in e+e- collisions at [square root of] s = 91.2 GeV with Archived ALEPH LEP1 data Badea, Anthony Shane Nicolae. Measurements of two-particle angular correlations for charged particles emitted in e+ e- collisions at a center-of-mass energy of 91 GeV are presented. The archived data are collected with the ALEPH detector at LEP. The correlation functions are measured over a broad range of pseudorapidity and full azimuth as a function of charged particle multiplicity. No significant long-range correlation is observed in both the lab coordinate analysis and in the thrust coordinate analysis, where the later is sensitive to a medium expanding around the color string between the outgoing qq̄ pair from the Z boson decay. The associated yield distributions in both analyses are in better agreement with predictions from the PYTHIA event generator than those from HERWIG, providing new insights into the hadronization modeling. These results serve as an important reference to the observed long-range correlation in proton-proton, proton-nucleus and nucleus-nucleus collisions. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2019; In title on title-page, "[square root of]" is the symbol. Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 135-145).

Mechanism for actuating seaweed harvesting device

Tue, 01 Jan 2019 00:00:00 GMT

Mechanism for actuating seaweed harvesting device Goul, Christopher. Mechanical systems to automate a critical aspect of the seaweed farming process were designed and iterated to determine their feasibility as a substitute for human labor on a commercial large-scale seaweed farm. This paper explores various proposed alternatives and the advantages and disadvantages inherent to each design, with the ultimate goal of determining a single system best suited for adoption by the commercial seaweed industry. Each mechanism was designed and critiqued according to the needs of US seaweed farmers, and evaluated over criteria such as cost, complexity, speed and efficiency. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 28).

Analysis of MIT's past and future energy expenditure/

Tue, 01 Jan 2019 00:00:00 GMT

Analysis of MIT's past and future energy expenditure/ Hartman, Michael(Michael J.),S.B.Massachusetts Institute of Technology. With the current rate at which technology is advancing, MIT has to update and replace out-of-date facilities as well as add new ones to stay at the forefront of university research. As MIT continues to expand its facilities, the amount of energy required to run those facilities will also increase. An analysis of future energy usage allows for energy saving systems to be planned before the facilities are complete, and implementation can be started before the energy has been spent. This thesis will be such an analysis on the energy usage of MIT's current capital projects, as well as the historical trends of MIT's energy usage. Conclusions will be drawn on how much these facilities or renovations will increase the university's energy expenditure by comparing facilities that currently exist to ones that are still in planning. By comparing the EUI of planned capital projects to that of existing facilities, a range was found for each facility's energy usage. Using this data, it was found that MIT will see a change in purchased energy between -16.5% and 4.28% by 2030. The low energy estimate matches with MIT's claimed -15% by 2030. The high energy estimate does not match, and shows that the rate at which MIT is currently expanding is not sustainable until 2030. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 24).

Transport of n-alkanes through graphene nanoporous atomically thin membrane

Tue, 01 Jan 2019 00:00:00 GMT

Transport of n-alkanes through graphene nanoporous atomically thin membrane Han, Kyung-Eun. Accurately characterizing molecular transport through a nanoporous atomically thin graphene membrane is important in determining potential for graphene's application as a filter. Amongst many factors that affect the transport, the effect of size of molecules is analyzed in this paper. Diffusion of n-alkanes between C10 and C18 was analyzed to isolate the effect of molecule size in transport trends. The n-alkanes are chosen as the solutes for their similar long-chains but differing lengths. Differently branched structures cause variable interactions with graphene between molecules. Thus, this structural consistency in n-alkanes make them optimal solutes. Additionally, these molecules are comprised of only carbon and hydrogen, allowing the same functional groups and polarities. However, their distinct boiling points allow detection in the gas chromatography-mass spectrometry (GCMS).; A diffusion cell with feed and permeate chambers, separated by a semipermeable membrane, was used to induce diffusion with difference in solute concentration between the chambers. Diffusion concentration and rates were calculated using GCMS analysis of samples taken over 6-hour period during the diffusion. The calculations were done for diffusion with and without graphene membrane for comparison. When integrating the GCMS peaks, two types of integration methods - wide-peak and narrow-peak integrations - were used to estimate the error due to difficulties in identifying peak boundaries. These results were further compared to the inherent diffusivity coefficients of the molecules, in order to quantify the selectivity imparted by graphene for diffusion. The diffusion trends from each data set were compared to the diffusion trend from inherent diffusivity coefficients, which shows that diffusiyity should decrease with larger and heavier n-alkanes.; The experimentally obtained data shows that smaller molecules diffused at faster rates, and there was a noticeable drop in the diffusion transport between C 12 and C 14. This is consistent with the expected trend. Studies that minimize sources of errors are recommended to further understand the transport of alkanes through graphene. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 67-68).

Design and implementation of a pair of robot arms with bilateral teleoperation

Tue, 01 Jan 2019 00:00:00 GMT

Design and implementation of a pair of robot arms with bilateral teleoperation Hattori, Alexander. Modern robotics has progressed in the manufacturing industry so that many manual labor tasks in assembly lines can be automated by robots with high speed and high positional accuracy. However, these robots typically cannot perform tasks that require perception or disturbance rejection. Humans are still needed in factories due to their innate ability to understand situations and react accordingly. Teleoperated robots can allow human perception to be combined with the dexterity and safety of a robot as long as the user interface and controls are carefully designed to avoid hindering the operator. Force feedback bilateral teleoperation is one method for providing users with an intuitive user interface and feedback. This thesis documents the design, construction, and implementation of a pair of bilateral teleoperated robotic forearms, each consisting of a 2 degree of freedom wrist, and a gripper. The forearm uses commercial off the shelf actuators in order to keep cost and additional development time low, while also testing the feasibility of using non-custom actuators. Development of the forearms included design and manufacturing of the mechanical assemblies, implementation of high-speed communication protocol, and tuning of control parameters. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 35).

Analysis of publicly available data to explore the role of assist in the NBA

Tue, 01 Jan 2019 00:00:00 GMT

Analysis of publicly available data to explore the role of assist in the NBA He, Wei Xun,S.B.Massachusetts Institute of Technology. In most team-based ball sports, the ability to pass the ball is an important aspect of a team's offense. While most teams understand that passing the ball well can create valuable offensive opportunities and win games, many traditional teams still view passing as an ambiguous art form. On the other hand, the advanced teams are using data to make data-driven decisions about their passing. Specifically, the NBA has collected a wealth of data over the past few decades, and teams are trying to transform this data into valuable insights that can help them edge their competition. Using publicly available data, I explored how the passing dynamics of teams compare across seasons and teams, and created diagrams to better communicate the assist relationships between teammates (see Appendix). This information has revealed interesting insights regarding individual players, teams, and the greater league. Through this research, I hope to help teams better understand the science of passing so they can make more informed basketball decisions. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 48-49).

Modeling and control of a four wheel drive Formula SAE car

Tue, 01 Jan 2019 00:00:00 GMT

Modeling and control of a four wheel drive Formula SAE car Hua, Cheyenne D. Formula SAE is a collegiate design competition in which student teams design, build, and race an electric formula racecar every year. In 2019, the MIT team built its first four wheel drive vehicle. The new architecture requires more robust and performant control systems. One major challenge is that the vehicle is not functional for the majority of the year. A longitudinal vehicle simulation was written and tested for the purpose of testing control algorithms without a physical testbed, as well as to learn more about vehicle behavior in general. The simulation was written in Simulink and the structure kept versatile so that it could be easily expanded in complexity in future years. Test data was used to successfully correlate the model to the actual system. Several launch control algorithms were also tested using this simulation, for both a rear wheel drive and four wheel drive architecture. Although basic, the control schemes produced promising results for both speed and stability, notably the normal force proportional controller. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 42).

Gastric-resident drug delivery system for prolonged gram-level dosing of Tuberculosis treatment

Tue, 01 Jan 2019 00:00:00 GMT

Gastric-resident drug delivery system for prolonged gram-level dosing of Tuberculosis treatment Ikeanyi, Chinonyelum. Medication non-adherence is one of the biggest challenges facing effective treatment of disease around the world. In developing and developed countries, approximately 50-70% of patients fail to correctly follow the drug regimen prescribed by their health care providers. Gastric resident systems have the potential to improve medication non-adherence as they enable more infrequent dosing, a key recognized determinant of improved adherence. A number of diseases could benefit from a change in treatment protocol in particular those requiring prolonged treatment courses with high pill burdens and where non-adherence could manifest in significant morbidity and mortality to the individual and the public as is the case for communicable disease. Tuberculosis is a disease that requires up to approximately 100 grams of medication to be taken each month for effective treatment. Previous gastric resident devices are limited in their drug loading capacity with most holding less than 500mg at a time. Recently, a multigram gastric resident drug delivery system applied towards the treatment of tuberculosis was reported. This system had to overcome several challenges and several remain. In this thesis, specific contributions made over the last two years to address the device's limitations as well as future improvements will be documented and their significance explained. Namely, working to achieve pulsatile release as well as sustained release through the use of water dissolvable polymer films, increasing the drug load capacity of the device (going from uncompressed powder to pills), and the creation of a high-throughput hole punch device that increased the efficiency of the manufacturing process. These improvements helped to facilitate the creation of gastric-resident device that will be used to affect the lives of patients around the world. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 31-32).

Factors contributing to pain in military helicopter pilots

Tue, 01 Jan 2019 00:00:00 GMT

Factors contributing to pain in military helicopter pilots Johnson, Lauren(Lauren E.),S.B.Massachusetts Institute of Technology. It is commonly accepted that for military helicopter pilots, neck and back pain is part of the job. This pain can decrease pilot situational awareness, increase medically related downtime, and increase healthcare costs incurred due to pilots. This literature review analyzes factors that contribute to neck and back pain and injury in military helicopter pilots, evaluates effectiveness of exercise regimes in mitigating pain, and assesses the potential for engineering design changes to reduce pain. Most of the reviewed literature confirms that exercise could be an effective means at decreasing pain in pilots; however, there was no universal finding regarding the impact of factors such as height, age and flight hours, gender, and airframe on pilot pain and injury. These topics remain worthy of further study as it is important to fully understand what factors contribute to pilot pain so they can be addressed in future military helicopter cockpit designs. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 14-15).

Variable stiffness orthosis for gait normalization in patients with toe walking

Tue, 01 Jan 2019 00:00:00 GMT

Variable stiffness orthosis for gait normalization in patients with toe walking Huerta, Alyda. Duchenne muscular dystrophy (DMD) is an X-linked recessive neuro-muscular disorder that causes progressive muscle degeneration. DMD patients tend to walk on their tip toes because of their weak calf muscles and currently do not have many options for managing the fatigue induced by supporting most of the foot strike impact with the ball of their feet. Patients with Idiopathic Toe Walking (ITW) suffer from similar symptoms and lack of physical support when walking. The addition of external heel support through an orthosis attached on the exterior of the heel of the shoe may help reduce this fatigue and correct the tip toe gait of DMD and ITW patients, enabling them to walk for longer distances unassisted. In order to study the effect of additional heel support with an orthosis, a custom orthosis with variable stiffness cushioning was designed. A healthy subject walked with simulated tip toe walking observed in DMD and ITW patients on a treadmill for three thirty-second trials, each with a cushioning material of rubber, gel, or foam added to the orthosis. The force on the foot, calf muscle activity, and video were recorded. Controls of "normal" walking and tip toe walking without prototypes were used for baseline comparisons. Material firmness and Young's modulus were measured for each of the materials with a compression test using a texture analyzer. There was a significant decrease in muscle activity from the tip toe control with the foam orthosis for both feet and for all orthosis materials for the right foot. There was also a significant improvement in heel-to-ball force ratios for all orthosis materials compared to the tip toe control. There was no observed correlation between material firmness and Young's modulus with muscle activity or heel-to-ball force ratio. The gait analysis from the video showed a gait appearance closer to that of the normal control than the tip toe control with the orthoses.. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 33-34).

The development and characterization of soft robotic contractile actuators

Tue, 01 Jan 2019 00:00:00 GMT

The development and characterization of soft robotic contractile actuators Hua, Sarah T. In this paper, I describe the development of a soft-robotic myocardium and pneumatic artificial muscles (PAMs) that replicate the physiological motion of the heart. We were able to generate physiological twisting motion in a confined geometry, but additional actuators would be required to generate physiological force for blood ejection. However, McKibben PAMs with thermoplastic polyurethane (TPU) bladders were too bulky and prevented the embedding of additional actuators. Therefore, multiple alternate PAM designs which occupy minimal unpressurized volume were explored. Of the various bladder and mesh pairings for traditional McKibben PAMs, latex bladders with nylon braided mesh proved the most promising. 2D PAMs with zero volume bladders were also developed: 2D McKibben, 2D Pleated, and 2D Cardiac Geometry PAMs. Candidate PAMs were characterized and compared to the physiological linear contraction (14.7%) and force generation (60N) of the heart. The 2D PAMs successfully reduced the volumetric footprint and were able to generate a maximum force of 0.46 N/cm3 (7mm-width five channel 2D McKibben PAM matrix), close to the amount generated by the baseline TPU PAMs (0.53 N/cm3), and up to 10.1% linear contraction (3mm-width nine channel 2D McKibben PAM matrix). However, none of the PAM matrices characterized were able to meet both linear contractile and force generation targets. With more characterization and iteration, the 2D PAMs seem promising for the biomimetic soft-robotic myocardium application. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 51-52).

Concussion preventative head-gear in contact sports

Tue, 01 Jan 2019 00:00:00 GMT

Concussion preventative head-gear in contact sports Jurko, Adam. This thesis explores the concussion preventative head-gear used in four contact sports: football, baseball, soccer, and basketball. The most effective head-gear from each sport is presented along with the reasons behind their success. Football and baseball organizations have regulations set in place for players to be required to wear helmets, while soccer and basketball organizations do not require players to wear any sort of head-gear. This thesis presents the reasons why soccer and basketball organizations do not require players to wear head-gear, but it also shows the equipment that have been used by players in the past to prevent further head injuries. This paper includes a personal anecdote as well as a recommendation for soccer organizations to require head-gear during competition and for basketball organizations to fund research into protective equipment specific to basketball players. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 23-24).

Design of a novel electromechanical gastric resident device for long term controlled drug delivery

Tue, 01 Jan 2019 00:00:00 GMT

Design of a novel electromechanical gastric resident device for long term controlled drug delivery Koeppen, Ryan(Ryan P.) Medication non-adherence is a global problem in health which has drastically hindered efforts to eradicate widespread diseases such as tuberculosis. Non-adherence has adverse effects on treatment efficacy and in the area of infectious disease it can increase the likelihood of developing antibiotic resistance to treatments. Despite global intervention efforts, non-adherence persists because the burden of administering medication is often placed directly on patients. One proposed strategy for overcoming non-adherence is the use of gastric resident devices, which are devices that hold large doses (-10-100 grams) of medication and deliver the medication in a controlled manner over long time periods (on the order of a month). Most gastric resident devices developed to date do not have the ability to load large doses of medication and release the pills in a controlled, pulsatile manner. Instead, they rely on continuous release processes which may not be sufficient for many treatments. This thesis details the design of a gastric resident device which can load approximately one week of medication and release the medication at a frequency of one pill per day using an electromechanically-driven mechanism. The device contains onboard electronics and a miniature direct current (DC) motor to drive a linkage that creates a reciprocating, linear motion at the output link. Intermediate, proof-of-concept tests were conducted to validate material choice, mechanism functionality, and mechanism reliability. A bench level prototype was developed and demonstrated the ability to release six pills from the action of controlled, electrical triggering only. Future work is being done to incorporate retention capabilities and self-contained electronics to make the device safe and autonomous for in vivo testing. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 69-70).

Autonomous active ankle exo-skeleton devices provide metabolic cost reduction

Tue, 01 Jan 2019 00:00:00 GMT

Autonomous active ankle exo-skeleton devices provide metabolic cost reduction Koo, Bon Ho Brandon. In this thesis, I designed and conducted an experiment that looks to confirm the metabolic cost decrease associated with the usage of an autonomous active ankle exoskeleton. The primary method to identify the associated metabolic costs was through the comparison of cardiovascular and respiratory activity during gait with and without the use of the exoskeleton. Rates of oxygen consumption, carbon dioxide production, and pulse were recorded for both control and experimental trials. Using these physiological responses, associated energy expenditure rates were calculated. The results of these trials suggest the presence of a quantifiable reduction in energy expenditure rate seen by the implementation of an autonomous active ankle exoskeleton in flat-terrain walking protocols. Additionally, the time to convergence, defined as the time a particular data-set takes to reach steady-state, was calculated using the same physiological responses. The results of this observation suggest that the time to convergence of metabolic indicators is much shorter than previously assumed. Finally, the potential benefits of utilizing a custom exoskeleton interface are quantified and elaborated. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 35-36).

Modular auger design to prevent clogging in suction

Tue, 01 Jan 2019 00:00:00 GMT

Modular auger design to prevent clogging in suction Leathrum, Travis. A mechanical design was conducted for a modular auger system that reduces the risk of clogging in suction piping meant to process sargassum seaweed. The auger supports a slurry pump-based system being designed to address sargassum blooms adversely affecting beaches in the Caribbean. By reducing clogging, the auger will prevent damage to the pump and reductions in productivity. A mathematical model of the auger system was created, then a small-scale physical model was built to test the concept. These tests exposed flaws in the mechanical details of the design, but the viability of the concept was shown, so a full-scale design was completed to be implemented as a backup in an extended field test that will be conducted in the Caribbean during the summer 2019. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 47-48).

A stress-reducing explorable musical object

Tue, 01 Jan 2019 00:00:00 GMT

A stress-reducing explorable musical object Lienhard, Hannah Rhiannon In this thesis, an explorable musical object - which is meant to help reduce anxiety and stress in the user - was designed and built. Using the program Pure Data, output data from an Arduino was manipulated to create varied tones when several pressure, bending, and soft potentiometer sensors were activated. These sensors were embedded in a soft, spherical outer shell made of roto-cast silicone. The final object was fully contained within this outer shell, as a Raspberry Pi computer was used to run Pure Data so it did not have to be plugged in. The sound created was output through a radio transmitter connected to a radio and headphones, again so the instrument could be fully contained within its outer shell. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 33).

The design and performance of a low-cost inflatable wheelchair seat cushion

Tue, 01 Jan 2019 00:00:00 GMT

The design and performance of a low-cost inflatable wheelchair seat cushion McCoy, Shannon E. K. For wheelchair users, the use of wheelchair seat cushions is vital to preventing life-threatening pressure sores, but high quality air cushions are often too expensive and inaccessible for many people. Given the prevalence of pressure sores, there is a need for a more accessible alternative to expensive air cushions. The design of a low-cost inflatable wheelchair seat cushion made of bicycle inner tubes, the Loop cushion, was evaluated through conducting user research interviews and performance tests as outlined in the ISO standards regarding wheelchair seat cushions. Ten tests were conducted on the Loop prototype, including accelerated aging, interface pressure mapping, hysteresis, impact damping, loaded contour depth, envelopment, 10% force deflection, horizontal stiffness, and sliding resistance. An additional test was conducted to evaluate the cushion's pressure distribution in tilted conditions. The results of the above mentioned tests were compared with published data of other cushions, particularly the ROHO High Profile cushion and foam cushions, where available. Loop performed comparably to the ROHO cushion and outperformed the foam cushions on many counts, showing that it is a promising cushion design. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 55-57).

Effect of geometry under emitter membrane on pressure compensating performance

Tue, 01 Jan 2019 00:00:00 GMT

Effect of geometry under emitter membrane on pressure compensating performance McLaurin, Tristan(Tristan J.) In order to better understand pressure compensating drip irrigation emitters, an experiment was carried out in order to characterize the effects of emitter dimensions under the membrane on emitter performance. Emitter performance was characterized by two models, an overdamped model and a piecewise model. A comparison of the models found an overdamped model to predict parameters with a greater degree of certainty than the piecewise model. No trends in emitter behavior could be identified with 95% certainty, but slight trends were noted for their ability to possibly inform future emitter design. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; "June 2019." Cataloged from PDF version of thesis.; Includes bibliographical references (page 55).

Design of a power limiter for an FSAE electric racecar

Tue, 01 Jan 2019 00:00:00 GMT

Design of a power limiter for an FSAE electric racecar Melendez, Alvaro J. MIT Motorsports is the Formula SAE team at MIT that has competed in Lincoln, NE since 2013. Last year's racecar performed exceptionally in all dynamic events but was disqualified from the endurance event due to a power violation. In order to prevent a violation in the following year, a power limiter was developed to ensure that the power consumption of the vehicle is reliably under the limit. Since weight and space come at a premium when it comes to an electric racecar, the power limiting approaches were implemented through C code in the car's Vehicle Control Unit. The power limiter makes use of a feed-forward mechanical power limiter combined with an electrical power limiter that makes use of the battery's power consumption with the use of a PI closed-loop controller. Powertrain efficiency calculations were performed to best model the power consumption of the vehicle. Testing became an essential tool used to develop, debug, and validate the power limiter. This year's power limiter will reliably keep the team under the power limit while minimally affecting performance to increase our potential at the next competition. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 23).

Scrap aluminum as fuel

Tue, 01 Jan 2019 00:00:00 GMT

Scrap aluminum as fuel Miller, Shannon(Shannon E.) The new development of a low cost, low risk aluminum fuel production method has extended the viable use cases of aluminum as a fuel. Scrap aluminum has the potential to provide fuel in disaster relief zones when infrastructure is ruined and scrap metal is abundant. Additionally, converting scrap aluminum to fuel can provide an alternate option to traditional recycling methods. The following paper presents various methods used to process and treat scrap aluminum and the resulting efficacy of these methods. Four different fuel production methods are presented. Parameters such as method of reforming scrap aluminum, percent mass eutectic in fuel, eutectic coating time, and pretreatment of aluminum cans are varied. The various methods achieved a wide range of efficiencies with the best being 57%. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 32).

Detection of launch frame in long jump videos using computer vision and discreet computation

Tue, 01 Jan 2019 00:00:00 GMT

Detection of launch frame in long jump videos using computer vision and discreet computation Muñiz, Pablo E.(Muñiz Aponte) Pose estimation, a computer vision technique, can be used to develop a quantitative feedback training tool for long jumping. Key performance indicators (KPIs) such as launch velocity would allow a long jumping athlete to optimize their technique while training. However, these KPIs need a prior knowledge of when the athlete jumped, referred to as the launch frame in the context of videos and computer vision. Thus, an algorithm for estimating the launch frame was made using the OpenPose Demo and Matlab. The algorithm estimates the launch frame to within 0.8±0.91 frames. Implementing the algorithm into a training tool would give an athlete real-time, quantitative feedback from a video. This process of developing an algorithm to flag an event can be used in other sports as well, especially with the rise of KPIs in the sports industry (e.g. launch angle and velocity in baseball). Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 44).

Physiochemical properties of nonaqueous amine-containing electrolytes

Tue, 01 Jan 2019 00:00:00 GMT

Physiochemical properties of nonaqueous amine-containing electrolytes Mutty, Christopher(Christopher B.) Recent developments in Li-CO2 batteries have demonstrated the viability of using amines to electrochemically activate CO2 before reduction and yield kinetic benefits, but little research has been done to optimize this new system. This thesis investigates the reduction of amine-activated CO2 and the properties of nonaqueous amine-containing electrolytes. The equilibrium voltage of the discharge reaction was found to be greater than 3.1 V versus Li/Lie, which is significantly higher than the thermodynamic potential of direct CO2 reduction (2.8 V versus Li/Lie). The equilibrium voltage can be used in future research to determine cell overpotentials, which are key indicators of cell performance. The research also found that varying the electrolyte salt and the type of amine can greatly increase the ionic conductivity of the electrolyte. Specifically, solutions containing salts with larger cations and larger anions were generally found to have larger ionic conductivities. These findings indicate that there is room to improve on and optimize the recently demonstrated amine-promoted Li-CO2 battery through more research into electrolyte and amine properties. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 34-36).

Fabrication process and electromechanical characterization of a sliding connector system for modular stretchable electronics

Tue, 01 Jan 2019 00:00:00 GMT

Fabrication process and electromechanical characterization of a sliding connector system for modular stretchable electronics Nandy, Ananya. The development of stretchable electronics has opened the potential for novel types of wearable electronic devices that can conform to curvilinear surfaces. In the traditional wearable space, modularity has been explored as a way to make devices customizable and multi-functional. Extending modularity and customizability to stretchable electronics could allow improved data collection in contexts where traditional sensor deployment is more challenging, such as on the human body. However, the use of soft materials for creating the stretchable electronic circuits necessitates a solution to modular connections for which traditional rigid electrical connectors are not adequately suited. To address the electrical connection problem, a process was developed for fabricating a new custom connector that was intended to be integrated more easily into the stretchable electronic circuit. The sliding custom connector was evaluated against integrating off-the-shelf electrical connectors into the stretchable substrate. It was found that the custom connector had several desirable traits in comparison to the existing connectors, including a low profile, good form factor at the band interface, and easier integration into a stretchable substrate. In addition, the connector was able to achieve an average of 12.1% strain before failure, higher than the maximum 8.7% strain achieved by the snap-button, a tested off-the-shelf connector. However, the custom connector resistance was much higher, on the order of 10 [Omega] in comparison to between 0.2 and 2 [Omega] in the tested off-the-shelf connector systems. It will be necessary to pursue further iterations to reach the electrical properties afforded by the tested off-the-shelf connectors and to increase the strain before failure. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 48-49).

Reverse-engineering and restoration of a four stroke single cylinder universal fisherman marine engine

Tue, 01 Jan 2019 00:00:00 GMT

Reverse-engineering and restoration of a four stroke single cylinder universal fisherman marine engine Nettleton, Coby Austin. To understand the inner workings of a 4-stroke engine and all of its components, a complete computer aided design (CAD) model was created of a historic marine engine. The parts were cleaned, measured, modeled in CAD and assembled. To ensure longevity of the rebuilt engine, original parts were repaired and, where necessary, new parts were fabricated. Fixing parts and post machining new castings allowed for machining practice on complex rough castings. The rebuilt engine was tested and successfully ran approximately seventy five years after this engine was first built. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 53).

Quantifying coordination of human gait : fall risk and effects of aging

Tue, 01 Jan 2019 00:00:00 GMT

Quantifying coordination of human gait : fall risk and effects of aging Oeding, Jacob F. Falls have become an immense source of physical, social, and economic hardship among older adults. Compromised coordination, defined as a decrease in the ability to properly time the motion of body segments with one another, is thought to be one factor contributing to the high rate of falls in older populations. Thus, coordination is often used by clinicians as a measure to help identify a patient's risk of falling, as well as by therapists to design targeted rehabilitative programs with the goal of reducing that fall risk. However, these assessments are currently evaluated subjectively, motivating the need for an objective measure of coordination. The aims of this study were to assess age-related differences in inter-joint coordination during the timed "Up and Go" (TUG) test of functional movement in an attempt to provide more information regarding the underlying coordination patterns of older adults that might contribute to an increased fall risk. Motion data from fourteen older and fifteen young adults performing the TUG test were analyzed using the Relative Coordination Metric (RCM). Significant differences in TUG task completion time were found between young and old populations. While TUG task completion time has been shown to correlate strongly with fall risk, no significant differences in RCM values were found when averaging across the gait phases. While older adults might require more time to complete a TUG task, the basic inter-joint coordination patterns utilized during gait seems to be preserved, suggesting a potential mechanism by which the brain is able to compensate for physiological changes due to aging. Thesis: S.B. in Engineering, Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 20-21).

Design and development of mechanical metatarsophalangeal joint for powered ankle-foot prostheses

Tue, 01 Jan 2019 00:00:00 GMT

Design and development of mechanical metatarsophalangeal joint for powered ankle-foot prostheses Palmer, Jasmin Elena. This thesis seeks to explore passive designs for a mechanical alternative to the metatarsophalangeal (MTP) joint, a critical anatomical component in human feet which allows for various types of anatomical motion. Our goal is to design a system that will act as a platform to test a proof of concept for a passive ankle-foot prosthesis with an MTP joint, but can also be adapted to use an actuated joint in the future. To increase the user's range of motion, our aim was for the mechanical MTP joint to achieve a maximum 600 dorsiflexion angle. We developed 2 MTP joint designs (Rubber Hinge and Fabric Hinge) with 2 body geometries varying at the heel for each (Traditional Heel and Inverted Heel) for a total of 4 models. We performed a static load Finite Element Analysis (FEA) using the Solidworks FEA Simulation Tool. The FEA was performed under the worst-case static load scenarios for the toe and body components of the prosthesis, standing on tiptoe with a dorsiflexion angle of 60' for the toe components and standing with all weight on the heel for the body components. The simulation yielded that not only did no components experience any irreversible deformation, but that the Rubber Hinge design had a minimum safety factor of 5.7, 10, and 4.5 for the Toe, Inverted Heel Body, and Traditional Heel Body respectively and the Fabric Hinge Design had a minimum safety factor 1.4, 9.9 and 4.5 for the Toe, Inverted Heel Body, and Traditional Heel Body respectively. This informed us that though both designs did not undergo failure under the prescribed loads, material utilization was in excess and could be further optimized to decrease the weight. Future designers should focus on implementing this platform into high fidelity physical models to be tested under various static and dynamic loading conditions as well as further optimizing the dimensions of the prosthesis. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 46).

Development of a low-cost, low-volume alternative for purification fraction collection

Tue, 01 Jan 2019 00:00:00 GMT

Development of a low-cost, low-volume alternative for purification fraction collection Piotti, John(John S.) An essential aspect of chemical research is the ability to accurately and repeatably isolate and extract different compounds from a chemical mixture. In a lab setting, this process is often automated via benchtop devices that can breakdown a sample mixture and collect the individual compounds. However, these systems are often large, expensive, and difficult to customize. This research sets out to design, build, and test a small, low-cost system that can be deployed in a variety of lab settings as an alternative to a larger industrial system. This research focuses on the chemical process of separation and fraction collection, as well as the mechanical and computational development of the prototype system. Through trial experimentation, it was found that the prototype system performs comparatively to commercial platforms, and offers unique benefits such as reduced size, an accessible design, and ease of customization. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 41-43).

Development of techniques to determine temperature coefficient of resistance

Tue, 01 Jan 2019 00:00:00 GMT

Development of techniques to determine temperature coefficient of resistance Seo, Scott Y. The focus of this thesis was to develop a simple, repeatable method for characterizing the relationship of different materials' electrical resistance with respect to temperature. A measurement of this relationship is the temperature coefficient of resistance (TCR). Determining the TCR allows a material to be used as a temperature probe and can be utilized in thermal conductivity measurements. The test apparatus and measurement setup proved capable of determining the temperature coefficients of resistance of a copper-alloy wire and a carbon film resistor, giving TCR values of 0.0036 1/K and -0.00014 1/K, which was consistent with their published values. The work of this project aims to aid in the development of a micro-cooling system, which uses polycarbonate for its heat exchanger at cryogenic temperatures. A potential carbon film temperature probe was tested, but was found to be unfit for the intended use as a temperature probe on a polycarbonate surface due to catastrophic failures in the film, most likely caused by the different thermal expansion rates of the carbon and polycarbonate. Further research should be conducted to first find a more suitable temperature probe for polycarbonate and then conduct tests at cryogenic temperatures. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 27).

Design & analysis of a parallel drive spherical rotation mechanism for application in high tech farming robots

Tue, 01 Jan 2019 00:00:00 GMT

Design & analysis of a parallel drive spherical rotation mechanism for application in high tech farming robots Rose, JamiLynn. Increasing global use of pesticides has resulted in a significant amount of pollution which continues to harm the life and ecology of our planet. This thesis proposes and investigates a mechanized alternative to chemical pesticide use which employs high tech farming robots to directly identify and eliminate harmful insects and invasive plant species in agricultural settings. We focus specifically on the design and control of a parallel drive spherical rotation mechanism capable of manipulating a miniaturized steam jet ejector along the surface of a sphere. The jet ejector is capable of shooting out a lethal high-pressure steam jet towards the targeted pest while the rotation mechanism allows for fast and precise control of the jet ejector through a full hemisphere of rotation. This is well beyond the small angle range achieved by other commonly utilized parallel drive mechanisms such as the Gough-Stewart Platform. The design of the parallel spherical rotation mechanism was inspired by a similar parallel manipulator invented by Professor Ian Hunter in 1990. The mechanism design was simplified, miniaturized, and adapted to fit the design requirements of our specific use case. The forwards kinematics of the mechanism as well as the mathematical inversion problem are analytically solved for. An alpha prototype of the device is designed, constructed, and controlled using the derived equations. Through testing the device demonstrated targeted levels of precision and repeatability. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 57-59).

Gaze tracking : seeking critical information for autonomous excavation

Tue, 01 Jan 2019 00:00:00 GMT

Gaze tracking : seeking critical information for autonomous excavation Shiozawa, Kaymie. Automating excavation in mining and construction applications is crucial today as the supply of skilled operators cannot match market demand. To efficiently make control decisions for autonomous excavators without having to take in all visual inputs from a typical operator's field of view, gaze tracking is employed in solely extracting key visual information that skilled operators use in the field. Both a front facing camera depicting the world view of the subject and two eye facing cameras that track the subject's pupil movement are worn by a subject to identify regions and features that are of high interest to operators during a digging task. Key features, such as the interface between the soil and the bucket, are characterized using U-Net, a Convolutional Neural Network designed for image segmentation. Through this study, key regions, the inside of the bucket and the opening of the bucket, as well as key features, the soil-bucket interface, were identified to be of high interest to subjects. This information can serve to identify only the necessary visual inputs in the control decision process, thus shortening computation time. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 37-38).

Choosing methods and metrics for design feedback

Tue, 01 Jan 2019 00:00:00 GMT

Choosing methods and metrics for design feedback Steindl, Riley M. Collecting feedback is an invaluable part of the design process because it helps inform useful and effective changes to products. With a multitude of different methods for gathering feedback and metrics for evaluation, it can be difficult to select the method and/or metrics that will provide the most useful feedback for a given stage of design. There is currently no condensed guide for selecting methods and metrics for feedback on the bases of stage of design, effort level, and data type. This study filled this gap through a literature review of 9 academic papers related to design evaluation methods and metrics. Following review, the information in these papers was analyzed to establish how evaluation methods and metrics relate to different stages of design, different data types, and relative effort levels. The result is description of the relationships between stage of design and suitability, evaluation method and data type, evaluation method and effort level, and evaluation metric vs data type. In all, this study provides useful information for designers to use when selecting the right evaluation methods and metrics to collect feedback on their designs. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 18-19).

De-noising and de-blurring of images using deep neural networks

Tue, 01 Jan 2019 00:00:00 GMT

De-noising and de-blurring of images using deep neural networks Fike, Amanda(Amanda J.) Deep Neural Networks (DNNs) [1] are often used for image reconstruction, but perform better reconstructing the low frequencies of the image than the high frequencies. This is especially the case when using noisy images. In this paper, we test using a Learning Synthesis Deep Neural Network (LS-DNN) [2] in combination with BM3D [3], an off the shelf de-noising tool, to generate images, attempting to decouple the de-noising and de-blurring steps to reconstruct noisy, blurry images. Overall, the LS-DNN performed similarly to the DNN trained only with respect to the ground truth images, and decoupling the de-noising and de-blurring steps underperformed compared to the results of images de-blurred and de-noised simultaneously with a DNN. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 12).

Digital modeling of 1930 Santos Hernandez classical guitar geometry

Tue, 01 Jan 2019 00:00:00 GMT

Digital modeling of 1930 Santos Hernandez classical guitar geometry DeShields, Andrew(Andrew D.) With advancement in computational power, it is possible today to create digital instruments with highly accurate geometry as well as material properties. Here, a Santos Hernandez classical guitar built in 1930, is digitally constructed in SolidWorks from plans of the actual instrument. The complete instrument consists of more than twenty parts, which were then meshed with appropriate finite elements in HyperMesh. This assembled finite element model can be analysed in any finite element solver such as Abaqus to understand the structural and acoustic wonders of such great instruments of the past, which would be very difficult to do otherwise. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 20).

Design of motor controller water cooling system for a Formula SAE electric racecar

Tue, 01 Jan 2019 00:00:00 GMT

Design of motor controller water cooling system for a Formula SAE electric racecar Demir, Asli. This thesis explores the design of a water cooled cold plate system for motor controller used in an FSAE Electric racecar. Models for pressure drop and rate of heat transfer along with the constuction of Computational Fluid Dynamics (CFD) simulations are presented to predict the pressure drop and heat transfer rate. The goal is to provide a framework to design cold plates for motor controllers, along with any other components that generate heat, such as the vehicle battery. A test bench is constructed to validate the results of the models used. Preliminary results show that while such models are useful in understanding the fundamental relationships between different variables and the properties of the flow, it is difficult to construct a model that predicts pressure losses reliably using introductory material on thermodynamics and heat transfer. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 39).

Modelling, design, and control of a spherical rolling robot

Tue, 01 Jan 2019 00:00:00 GMT

Modelling, design, and control of a spherical rolling robot Stuart, Anthony D.,S.B.Massachusetts Institute of Technology. Spherical rolling robots offer a number of advantages over traditional wheeled robots. Their geometry allows for increased mobility and the inability to tip over, while their enclosed design provides protection for the electronic and mechanical components driving the robot. However, these advantages come with significantly more complex system dynamics, with design parameters impacting system performance in sometimes non-intuitive ways. This thesis explores the effect of different design parameters such as sphere mass and center of mass location on the performance of a spherical rolling robot. A kinematic and dynamic model of the system was created, along with a first iteration of the mechanical design to generate realistic starting values for the simulation. The system dynamics were linearized and used to design a linear quadratic regulator (LQR) controller. Sphere mass and center of mass location were varied across a range of values and simulated to analyze the system's ability to quickly converge to position and velocity set points. This study found that increasing the mass of the sphere resulted in a linear increase in settling time, while increasing the radial distance between the center of mass and the sphere caused an exponential decrease in settling time, up until a critical point. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 37).

A joule heating mechanism for high-speed fused filament fabrication

Tue, 01 Jan 2019 00:00:00 GMT

A joule heating mechanism for high-speed fused filament fabrication Daguilh, Thad. Extrusion-based additive manufacturing, known as fused filament fabrication (FFF), is one the most accessible methods of rapid prototyping, capable of handling a wide variety of engineering thermoplastics. Productivity limitations hinder the further application of FFF to both prototyping and production. An FFF system consists of three synchronized processes: heat conduction into the feedstock, gantry speed, and extrusion of the feedstock by a pinch wheel mechanism. Each one of these processes can become a rate-limiting factor for prints. This work explores resistive joule heating as a method to increase heat transfer into an electrically conductive composite feedstock. This requires usage of an electrically insulating liquefier in order to co-locate both conduction and joule heating. A prototype mechanism was designed and fabricated including an anodized aluminum liquefier capable of printing. This was tested and no significant difference in print times were noted because of a failure in the system due to a current jump around the joule heating section. Although physical tests were not a success, a LabVIEW VI was created for future testing. In addition, modeling was performed to conclude that a 2.85mm PLA filament would be used in the range of 80-100V and 0.2-0.25A with a joule heating length of 0.75cm in the system in order to reach an extrusion rate of 200 cm³ /hr. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 31).

Characterization of ion-selective electrodes for an on-field soil nutrient analysis system

Tue, 01 Jan 2019 00:00:00 GMT

Characterization of ion-selective electrodes for an on-field soil nutrient analysis system Tregoning, Bailey. There is an established need for more careful application of soil nutrients and fertilizer to maximize crop yield for an ever-growing population. This study focuses on the manufacturing and characterization of ion-selective electrodes (ISEs) to further study if they could be used to reliably measure soil markers like nitrate, phosphate, potassium, and pH for farming applications. Research into a low-cost design for a soil nutrient analysis system to characterize the viability of farming soil has already begun through proof-of-concept prototypes and testing. This study builds upon such early-stage testing. The goal of this investigation was to build an understanding of the accuracy of these ion-selective electrodes in soil samples. To arrive at the end goal of this investigation, we divided this project into three main stages for these nitrate, phosphate, potassium, and pH ISEs.; Stage one focused on characterizing the performance of ISEs cured in environments with two different oxygen levels, in effort to describe the variation in slope and detection limit contributable to curing environment. This study found that ISEs cured in lower oxygen settings (-10 ppm) were more reliable. Stage two focused on characterizing the selectivity of ISEs for the target ion over interfering ions commonly found in soil, in effort to describe the magnitude of error in a soil measurement due to interfering ions with the ranges found in soils. This study found that the nitrate electrodes tested performed with reasonable selectivity for the interfering phosphate, sulfate, and carbonate ions. Stage three focused on benchmarking the accuracy of the ISEs against standard lab techniques for a library of soil samples. The soil concentrations calculated from the potentials measured by the ISEs were reasonable for some of the soil sample ranges, but not all of them.; The results from these three stages of testing imply that the manufacturing process needs to be updated to include conditioning the ISEs in strontium chloride in effort to improve the reliability and stability of the ISEs. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 48).

Design, analysis, and control of a nitinol shape memory alloy rotary actuator for spacecraft deployable structures

Tue, 01 Jan 2019 00:00:00 GMT

Design, analysis, and control of a nitinol shape memory alloy rotary actuator for spacecraft deployable structures Contreras, Mario Melendrez. Small satellites known as CubeSats are becoming more and more popular in the aerospace industry and in academia. The new availability of rockets such as SpaceX's Falcon 9 or even dedicated CubeSat rockets such as Rocket Lab's Electron rocket have provided a new opportunity for many organizations to launch satellites. Depending on the goals of each satellite, they can be configured with many different payloads and mechanisms. Solar panels are one of the most common payloads on CubeSats but are mostly spring-actuated, meaning they cannot be deployed to precise angles. Shape memory alloys have been used to create rotary mechanisms in the past but closed loop control of shape memory alloys in a bending architecture is relatively novel. A rotary shape memory alloy actuator was designed with the use case of precisely pointing solar panels to maximize energy collection. Here we show identification of a system transfer function through multiple step responses and the use of a closed-loop PID control to achieve rise times of about 15 seconds with overshoot errors of 2 to 8 degrees. The experiments also showed the possibility of achieving rapid rise times of less than 2 seconds and accuracy within 2 degrees with some slight changes to the control system. This actuator prototype further develops the possibilities of precision angular actuation in a lightweight, robust, low volume, low power, and simple mechanical system. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 34-35).

Design and build of artificial blood vessels with variable compliance

Tue, 01 Jan 2019 00:00:00 GMT

Design and build of artificial blood vessels with variable compliance Cimmino, Emily(Emily C.) To more accurately recreate hemodynamic conditions in a benchtop circulatory simulator, it is important to develop artificial blood vessels with tunable mechanical characteristics. These vessels simulate the varying properties of blood vessels at different regions within the circulatory system by mimicking the compliance and therefore recreating physiological flow velocities and pressure waveforms. The compliance of a blood vessel defines how its volume will change in response to a pressure change. This project recreates variable compliance through a mechanism called laminar jamming, which utilizes friction between layers to tune the stiffness of a composite material. In the first experiment, a sample of composites with a wide range of materials and designs were tested, and looped materials exhibited behavior most similar to the mechanics of blood vessels. In the second experiment, a sample of looped materials was tested to further characterize the effects of different parameters on the composite's response to laminar jamming. Finally, in the third experiment, laminar jamming was applied to a tubular composite to mimic the shape of a blood vessel, and changes in the artificial vessel's compliance were observed through its volume-pressure relationship. These artificial vessels will be incorporated into a benchtop circulatory simulator to mimic disease physiology and evaluate cardiovascular support devices. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 50).

Design of a FSAE cooling system

Tue, 01 Jan 2019 00:00:00 GMT

Design of a FSAE cooling system Chiu, Harriet Alicia. MIT Motorsports is a FSAE Electric team at MIT that designs, manufactures, and tests electric formula-style racecars to compete in an annual collegiate competition. The cooling system for the Model Year 19 vehicle must provide adequate cooling to the motors and motor controllers, meet power consumption requirements dictated by the low voltage battery, and minimize system mass. Fluid modelling and benchtop testing were used to select the most suitable pump, fan and radiator. Tube routing and mounting design also have to allow for serviceability. With the use of a cooling test bench, a flow architecture was developed, and components were modified and tested to meet specifications. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 24).

Design and development of a modular test machine for students in 2.001

Tue, 01 Jan 2019 00:00:00 GMT

Design and development of a modular test machine for students in 2.001 Bornhorst, Zoe. The Mechanical Engineering course, Mechanics and Materials I (2.001), focuses on providing an introduction to the mechanics of solids with applications to science and engineering. While the current curriculum teaches in-depth theory, it can be improved in applicable knowledge. The focus of this thesis is the design, development, and evaluation of a modular test machine for students to build throughout the course. The design and build challenge will force students to explore the inner-workings of loaded structures and material properties. The pursued design emphasizes learning potential, gaining a physical feel of the course material, and ease of construction. This addition will walk students through the process of building a two-part lever design with a significant mechanical advantage and then acquiring material data from the structure they have built. The design successfully measures the yield strength of a low-density polyethylene sample within its documented range. Initial testing of the structure with a group of previous 2.001 students resulted in an increased understanding of loading, material properties, and mechanical advantage, when compared to previous testing prior to structure introduction. Estimated outcomes of this new model display increased efficiency among students, saving them an average 4 months of delayed extracurricular activities, 30 hours of unnecessary work, and another 20 hours of poor designing. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 71-[72]).

Characterizing grippers for transmitting prosthetic device for upper limbs

Tue, 01 Jan 2019 00:00:00 GMT

Characterizing grippers for transmitting prosthetic device for upper limbs Chen, Michelle X.,S.B.Massachusetts Institute of Technology. In this thesis, I designed and tested various fingertip grippers for a wearable force transmitting prosthetic device. This device uses fluid displacement to provide force feedback to the user, allowing the user to feel how much force they are gripping an object with. The device consists of two molded rubber fingertips filled with fluid and actuated by a motor. Various strengths and shapes of the molded rubber fingertips were tested and characterized by how much force was required to displace a certain volume. With this data, the fingertips can be optimized for compactness in a more wearable design. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 33).

"Sump-Inlet" deployment linkage design for sargassum ocean sequestration (SOS)

Tue, 01 Jan 2019 00:00:00 GMT

"Sump-Inlet" deployment linkage design for sargassum ocean sequestration (SOS) Bockman, Samuel Jacob. Invasive floating sargassum seaweed has become a serious problem for Caribbean nations due to the blocking of fisheries and distinct rotten smell that disincentivizes tourism to these countries. The solution to this problem conceived in Luke Gray's master's thesis was to pump the sargassum to a depth where the hydrostatic pressure is sufficiently greater than the sargassum bladder internal pressure such that the bladders are compressed, and the plant sinks [1]. This would be achieved by feeding a mixture of sargassum and seawater through a suction hose to an onboard solids pump, which then transports the sargassum to a depth where the hydrostatic pressure renders the sargassum negatively buoyant. One inlet device, discussed in Gray's thesis, is called the "sump-inlet" which operates much like an oil skimmer, controlling and enforcing a high solids concentration by locating a weir close to the free surface of the water. Once sargassum and seawater flows over the weir, into the sump, the sargassum is dragged downward toward suction piping, against its natural rate-of-rise, due to the constrained cross-sectional area of the sump and the high downward fluid velocity. With this method chosen, a single DOF linkage system was needed to deploy the sump-inlet and constrain it during operation. The hydrodynamic response of this linkage must ensure that the weir stays at an acceptable depth, in as wide a range of sea states as possible, to avoid inconsistent solids concentration and dry-running. Dimensions and mass properties of the sump-inlet linkage were informed by Gray's hydrodynamics model [1]. This thesis focuses on structural analysis of the deployment linkage, deck frame, attachments, and pivot. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 42).

Exploring mechanisms for harvesting of farmed seaweed

Tue, 01 Jan 2019 00:00:00 GMT

Exploring mechanisms for harvesting of farmed seaweed Badr, Ali(Ali H.) In this thesis, I explore different harvesting mechanisms for farmed seaweed off of a line. The seaweed market is large and growing globally, and currently relies heavily on manual labor and coastal waters for the farming process. The main goals of the designed mechanisms are to achieve a simple, reliable system that can be implemented on seaweed farms and allow off-shore farming as well as increase overall efficiency by reducing the reliance on manual labor. Alongside a colleague, we designed and built three iterations of the mechanism and I propose a fourth design that we will be exploring in the future. The three designs center around different actuation and cutting methods. The first design uses a ski lift actuation method and a circular saw blade as the cutting instrument. The second design uses the same cutting method but a spool method for actuation (described in more detail in paper). The third design uses a suction method for cutting and has multiple actuation methods. The designed mechanisms are then tested with live seaweed. By comparing the results of these tests and evaluating each design across a few metrics that we learned by speaking to seaweed farmers and throughout the process of building the mechanisms, I propose a fourth theoretical design that aims to improve on all previous designs and meet the proposed design requirements. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 37-38).

Implementation of travelling waves on lifting surface for drag reduction

Tue, 01 Jan 2019 00:00:00 GMT

Implementation of travelling waves on lifting surface for drag reduction V'Dovec, Taylor. NACA series airfoils are the standard cross-section shapes for lift-generating surfaces widely used in both aeronautic and aquatic transportation. As with any wing, the key design goal of such airfoils is to attain a large lift-to-drag ratio, namely increasing the lift force while reducing the drag force. At moderate angles of attack, boundary layer separation begins near the trailing edge, and moves up to the leading edge as the angle increases. Such a phenomenon raises the form drag significantly, and a method of pushing the separation point back towards the trailing edge could improve the overall efficiency of the foil tremendously. One such new approach is to introduce a travelling wave on the lifting surface, a technique inspired by the undulatory motion of fish. In order to manufacture and test such a surface, first the necessary design specifications must be determined. Using NACA0012 and NACA0018 wings at a Reynolds number of 1 x 10 5, key parameters including the location of the point of separation on the wing, the angles of attack where the surface would be most effective, and the characteristics of the travelling wave itself were determined. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 27).

A waypoint-driven gradient descent solution for a parallel robot

Tue, 01 Jan 2019 00:00:00 GMT

A waypoint-driven gradient descent solution for a parallel robot Valdes, Gabriel(Gabriel D.) This project aims to introduce a more robust navigation architecture for the Triple Scissor Extender Robot Arm (TSERA) at the d'Arbeloff Laboratory for Information Systems and Technology. TSERA was developed to access a confined area through a narrow channel, commonly known as the last one-foot problem found in final assembly, inspection, and maintenance operations within the aviation, automobile, and industrial equipment industries. Inspired from plant growth mechanisms, the robot is built from a sequence of expandable segments that can each extend and tilt. The current path planning algorithm computes arm motion by solving a series of inverse kinematic relations for each segment. This requires a user input of a three-dimensional coordinate to a kinematics solver for a robot in a complex and unknown operating space with parasitic displacement characteristics. This new path-planning design allows users to instead input a desired orientation for an expandable segment, utilizes a gradient ascent algorithm to determine the three-dimensional coordinate that would allow for that desired orientation, and then creates waypoints across the path in order to ensure minimal displacement error and reduce chances of damage to the robot's motors all in realtime. This solution allows for a more intuitive user experience with TSERA and increases robustness of the robot itself. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 26).

Designing anisotropic friction through limit curve analysis

Tue, 01 Jan 2019 00:00:00 GMT

Designing anisotropic friction through limit curve analysis Vasquez, Elizabeth Danielle. Friction is an essential component of robotic manipulation which is highly dependent on contact surfaces. In practical applications, these surfaces are often anisotropic, a property that has been known to produce interesting movements in nature and uncertainty in human applications. Therefore, control of anisotropic frictional surfaces could result in more precise movement in manipulation, locomotion, and other facets touched by frictional contact. To arrive at such controllability, frictional force was collected across a spectrum of anisotropic micro-textures, and a limit curve was generated. Experimental data was analyzed in accordance to friction laws such as limit curve and maximum-inequality principle (MPI). Qualitative observation and residual sum of squares (RSS) was used to detect lack of normality and non-convexity within each limit curve. This lack of both normality and convexity contradicts MPI and suggests that an alternative model is necessary. Additionally, the anisotropic frictional behaviors observed advances the feasibility of "designing" micro-textures capable of controllable anisotropic friction. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 26).

Dependence of typing speed and accuracy on device type and familiarity

Tue, 01 Jan 2019 00:00:00 GMT

Dependence of typing speed and accuracy on device type and familiarity Veldee, Kim E. Typing has become increasingly present in modem lives through its uses in laptops, phones, tablets, and other consumer electronics. Current computers encourage high typing speeds by implementing mistake corrections such as "backspace" or "delete" keys, functions that were previously done by cross-outs or complete rewrites of the entire page. These mistake correction options have minimized the consequences for typing errors and have caused typists to place less importance on typing accuracy. As more models of electronic devices are placed on the market, users build familiarity with and skills for their specific device model. Twelve participants were asked to complete a series of thirty-two typing tests on various laptop keyboards and mobile phones. Measurements were taken of typing speed and accuracy on familiar and unfamiliar keyboards for both laptops and phone keyboards, and specific mistake types were counted and recorded.; The effects of Autocorrection were observed through the transcription of multiple passages with and without Autocorrection enabled. The results were compared between device types (phone vs. laptop keyboards), level of familiarity (personal vs. unfamiliar keyboards), presence of Autocorrection, participant sex, and undergraduate major. Participant sex and undergraduate major did not significantly affect typing speeds on phones or laptop keyboards. Participants typed approximately 20% faster on laptop keyboards than on phone keyboards. Participants decreased in speed when typing on unfamiliar phone and laptop keyboards (approximately 46% slower on phones and 2.7% to 5.5% slower on laptops) and typed about 10% slower when prohibited from utilizing the "backspace" or "delete" keys.; Misspellings were consistently the most frequent mistake type and account for approximately 50% of mistakes, along with bad ordering on laptops (approximately 30%) and incorrectly-located spaces on phones (approximately 20%). Participants who regularly enable Autocorrect typed about 20% slower on phones when Autocorrection was disabled. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 68-69).

Increased production of aligned cellulose nanofibrils using microfluidic mixture chambers

Tue, 01 Jan 2019 00:00:00 GMT

Increased production of aligned cellulose nanofibrils using microfluidic mixture chambers Weiss, Daniel(Daniel W.),S.B.Massachusetts Institute of Technology. In this thesis, the production of cellulose macroscale fibers from cellulose nanofibrils using flow focusing in microfluidic mixture chambers is examined and tested. This process accomplishes the difficult task of aligning cellulose nanofibrils and gelling them together to create macroscale cellulose fibers, and this study seeks to test the limit of macroscale cellulose fiber production using this method. Using a volumetric flow rate of 1.1 x 10-7 m3 /s, which is over 100 times greater than that from Nechyporchuk et al.'s 2018 experiments [11, cellulose nanofibrils were pumped through a microfluidic mixture chamber. Deionized water and hydrochloric acid were pumped through two different cross-flow channels at 5.28 x 10-7 m3/s and 1.32 x 10-6 m3 /s , respectively, to focus the nanofibril suspension flow. The mixture chamber was examined using video data to observe if the focusing and alignment of the nanofibril suspension occurs at these higher volumetric flow rates. Tests found that the flow can be narrowed to roughly 6% of its nominal width, and birefringence examinations indicate that the cellulose nanofibrils were being aligned due to the flow focusing. Furthermore, the use of an even higher volumetric flow rate is feasible for this process. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 33-34).

A Multi-modal Robot for Ground and Aerial Locomotion

Tue, 01 Jan 2019 00:00:00 GMT

A Multi-modal Robot for Ground and Aerial Locomotion Winston, Crystal(Crystal E.) This thesis describes the design and testing of a quadcopter that capable of both driving and flying. This was achieved by mounting quadcopter motors and propellers to the center of each of the robot's four wheels. The wheels are then capable of changing orientation in order to allow the robot to either drive or fly. Each of these wheels contains a gearing and bearing system that decouples the rotation of the wheels from the rotation of the propellers and also houses the system's landing gear. The prototype described in this thesis is capable of driving on flat surfaces as well as vertical take-off and landing. Further improvements to the system would be required in order for it to perform longer flights, complex aerial maneuvers, drive on uneven surfaces, or carry additional payloads. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 39-40).

Membrane deflection in inline drip emitters

Tue, 01 Jan 2019 00:00:00 GMT

Membrane deflection in inline drip emitters Villapando, Alyanna Zsalee. This study explores the behavior of membranes found within inline drip emitters when subjected to a concentrated load. Knowing the response of the membrane can be useful in optimizing future emitter designs for characteristics such as lower activation pressure. Two different types of membranes were studied, one from the Jain Turbo Cascade® emitters, and the other from the Jain Turbo Top® emitters. These membranes were placed in a fixture, and a texture analyzer fitted with a ball-end probe was used to measure the force exerted by the membrane at a given deflection. The results were compared to analytical models of the deflection of a simply-supported or clamped rectangular plate with a point load, and it was found that these models do not accurately describe the measured behavior. A sensitivity analysis of the models show that changes in the value of the membrane thickness have the greatest effect on change in theoretical deflection at a given force. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 25).

Design of a dual beam optical trap

Tue, 01 Jan 2019 00:00:00 GMT

Design of a dual beam optical trap Frejowski, Tom. Dual beam optical traps use radiation pressure from two counterpropagating laser beams to manipulate microscopic particles. Typical traps use optical fibers to guide those beams. This thesis proposes a design for the coaxial alignment of optical fibers that allows for the fibers to translate along a common axis while maintaining alignment. Additionally, this design enables the optical fibers and trapping samples to be quickly and easily swapped out for different experiments. A full optical trapping setup was constructed using this design and successfully demonstrated the trapping of multiple polystyrene microspheres. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 29-30).

Mechatronic design of an ISO 22675 prosthetic foot tester

Tue, 01 Jan 2019 00:00:00 GMT

Mechatronic design of an ISO 22675 prosthetic foot tester Liang, ZhiYi,S.B.Massachusetts Institute of Technology. Researchers in the Global Engineering and Research Lab (GEAR Lab) at MIT have been actively working on an improved design of the most widely distributed prosthetic foot in India, known as the Jaipur Foot. By developing an ISO 22675 prosthetic foot life cycle tester, researchers in GEAR Lab can test the durability of the prosthetic designs and fulfill the life cycle requirements. This thesis explores the mechatronic design of an ISO 22675 prosthetic foot life cycle tester and its contribution towards establishing fatigue testing infrastructure for prosthetics in GEAR Lab. It is broken down into three sub-systems: mechanical design, electrical design, and control architecture. It also serves as a documentation file detailing the engineering design decisions that were made during the development of the project. By building upon a mechanical framework that was established by past researchers, mechanical redesigns were conducted on the force loading assembly and the pivoting loading platform. The redesigned mechanical assembly were tested to be able to sustain maximum test force level with a safety factor of at least 1.5. The redesigned structure also provides adjustability to four crucial geometric parameters specified by the ISO 22675 standard and enables testing of prosthetic foot ranging from 23 cm to 31 cm in length. In addition, a system control PCB was designed and developed to serve as an electrical communication hub for reliable communication between the host controller LabVIEW myRIO-1900, various sensors, and the two actuators responsible for applying the test force and rotating the loading platform. A control architecture was developed and implemented through a LabVIEW parallel timed loop control structure to execute the control loop at a rate of 1kHz to reliably control both the stepper motor and the servo in parallel, read sensor states and display system current real time state through a graphical user interface. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 85-86).

"Space Became Their Highway" : the L-5 society and the closing of the final frontier

Tue, 01 Jan 2019 00:00:00 GMT

"Space Became Their Highway" : the L-5 society and the closing of the final frontier Glenhaber, Mehitabel. Introduction: In the 1970s in America, outer space became the locus for many imaginings of the future, from Gene Roddenberry's Final Frontier, to George Lucas's Galaxy Far Far Away, to NASA's own predictions for the future of manned space travel. Outer space has long held a sort of mystical sway over the human imagination. Throughout the 19th and 20th century, it has been the realm of science fiction and futurist imaginings alike- almost as if we want to fill the void with fantastical technologies and speculative civilizations. But in the Apollo Era especially, space took on a particularly vivid role in the popular consciousness - a vast new frontier just at the edge of humanity's reach. The question of what was out there, or what could be out there, was a compelling one for many Americans - whether they seriously believed in the possibility of space colonization or not.; The 70s vision of the future of space travel was a fraught site for many social conflicts, ranging from large geopolitical ones - would the future of space be American or Soviet? - to more local cultural ones - would space colonization and space flight support the values of the mainstream culture, or the counterculture, in America? In this paper, I explore 1970s hopes, fears, and imaginings for space through the lens of a particularly dedicated group of 1970s space enthusiasts: the L-5 Society, and their vision for a self-sufficient space station, located at earth's 5th Lagrangian point. In Dreamscapes of Modernity, Sheila Jasanoff calls for historians of science to study not only the history of actual technologies, but also what she refers to as "sociotechnical imaginaries" - historical imaginations of technologies which didn't quite exist yet.; By Jasanoff's definition, a sociotechnical imaginary is a sort of imagined landscape which a society constructs in order to explore the implications of current or future technologies. Sociotechnical imaginaries may be placed in the future, or in far away unexplored places; only, like Thomas More's utopia, or "no place", they must be somewhere we can't go - at least not yet.4 In her analysis, Jasanoff argues that sociotechnical imaginaries are rarely constructed by lone visionary authors. Instead, they are collaborative works of worldbuilding which members of a society all contribute to shaping. While core texts like works of science fiction, utopian novels, and economic or sociological predictions of the future can have a major role in shaping sociotechnical imaginaries, individual's beliefs about technology and the future help shape how these texts are read.; And these individual's reactions to and interpretations of these texts are what transform them from isolated pieces of writing into a landscape in the collective imagination. Furthermore, Jasanoff argues, the collaborative nature of sociotechnical imaginaries makes them a useful tool for historians. Because sociotechnical imaginaries are constructed collectively, they are often sites of negotiation, sandboxes where cultural conflicts over beliefs about, and hopes and fears for, new technology can be fought out, explored, and potentially reconciled. For these reasons, sociotechnical imaginaries often reveal contemporary cultural fissures and conflicts in a society that manifested in concerns about technology and the future. Though sociotechnical imaginaries may be entirely fictional, they are still worth taking seriously because they are constructed by real people, and reflect real conflicts in the real society that created them ... Thesis: S.B., Massachusetts Institute of Technology, Program in Science, Technology and Society, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 64-67).

Imaging black holes with simulated space expansions to the event horizon telescope

Mon, 01 Jan 2018 00:00:00 GMT

Imaging black holes with simulated space expansions to the event horizon telescope Palumbo, Daniel(Daniel C.) The Event Horizon Telescope (EHT) is a multinational Very-Long-Baseline Interferometry (VLBI) network of dishes joined to resolve general relativistic behavior near a supermassive black hole. The imaging quality of the EHT is largely dependent upon the sensitivity and spatial frequency coverage of the many baselines between its constituent telescopes. The EHT already contains many highly sensitive dishes, including the crucial Atacama Large Millimeter/ Submillimeter Array (ALMA), making it viable to add smaller, cheaper telescopes to the array, greatly improving future capabilities of the EHT. We explore the feasibility of adding small orbiting dishes to the EHT, and develop orbital optimization tools for space-based VLBI imaging. Unlike the Millimetron mission planned to be at L2, we specifically treat low and medium Earth orbiters which rapidly fill spatial frequency coverage across a large range of baseline lengths. Finally, we demonstrate significant improvement in image quality when adding small dishes to planned arrays in simulated observations of both SgrA* and M87. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 47-52).

Statistically-based two-dimensional finite element analysis of problems with uncertain stiffness and strength properties

Wed, 01 Jan 1986 00:00:00 GMT

Statistically-based two-dimensional finite element analysis of problems with uncertain stiffness and strength properties Quigley, Joseph J. Thesis (Mech. E.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1986.; Bibliography: leaf 143.

Gamma ray production cross sections of proton bombardment of fluorine for light element analysis and depth profiling

Tue, 01 Jan 2019 00:00:00 GMT

Gamma ray production cross sections of proton bombardment of fluorine for light element analysis and depth profiling Pham, Monica. Due to the interdependence of fusion reactor performance and the surface conditions of the plasma facing components (PFC), diagnostic techniques that monitor the conditions of PFCs are useful. One ion beam analysis (IBA) diagnostic technique utilizes particle induced gamma emission (PIGE) analysis to diagnose the conditions of PFCs. Gamma production differential cross section data is essential to PIGE because it provides a way predict and interpret data. Fluorine may be a candidate for this technique because it is low-Z and not typically intrinsic to fusion reactors. However, differential cross section measurements for 19F(p, [alpha] [gamma])16O do not exist yet. Differential cross section measurements for the 19F(p, [alpha] [gamma])16O reaction have not been measured primarily because of the difficulty of deconvolving overlapped peaks in the gamma ray spectra of the reaction. This work presents, for the first time, the 6.13 MeV gamma production differential cross section for the 19F(p, [alpha] [gamma])16O reaction in the 840 to 1520 keV energy range. Although there exists gamma yield data for this reaction in Dababneh et al. [1], yield measurements can only be used as a comparison or for relative measurements. Additionally, previous yield measurements relied on integrating the entire spectrum with approximate bounds of 4.5 to 9 MeV likely due to overlap of peaks. In this work, yield of the 6.13 MeV full energy peak was obtained by deconvolving overlapping peaks by utilizing the constant ratio of the double escape and the single escape peaks. The subsequent yield curve was converted to differential cross section. The presented differential cross section measurements expands current knowledge and contributes to diagnostic techniques that utilize gamma production reactions. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2019; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 42-43).

Predicting genomic interactions using deep learning

Tue, 01 Jan 2019 00:00:00 GMT

Predicting genomic interactions using deep learning Syed, Tahin Fahmid. Physical promoter-enhancer and CTCF-CTCF interactions organize the human genome in 3-dimensions, and contribute to the regulation of gene expression. Hi-C and related approaches have enabled profiling of these interactions, though how the instructions for these interactions are encoded in the genome is still largely not understood. We develop a deep learning model, Deep3DGenome, to predict genomic interactions using both genomic sequence data and chromatin features. We find that a machine learning model that has anchor specific modules and uses rich chromatin features outperforms previous approaches at predicting 3D interactions. Thesis: E.C.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 39-43).

Classifying teams in the NBA with player behavioral data

Mon, 01 Jan 2018 00:00:00 GMT

Classifying teams in the NBA with player behavioral data Poler, Colin(Colin M.) I use SecondSpectrum play-by-play data from the 2016-2017 NBA season to assemble behavioral event data for each player. Behavioral data includes propensity to dribble/pass/shoot, and also the resulting quality of shot when players decide to shoot or make another pass. I apply a k-means clustering algorithm to cluster teams based on their starting lineup behavior data; the clusters show different team makeups within the behavioral data collected. In particular, the clustering identified pass-heavy vs dribble-heavy offenses, and good shot-decision making teams. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018; Cataloged from PDF version of thesis.; Includes bibliographical references (page [25]).

Commercialization of a masonry tool designed in a senior-capstone class through a licensing agreement

Mon, 01 Jan 2018 00:00:00 GMT

Commercialization of a masonry tool designed in a senior-capstone class through a licensing agreement Rudoltz, Hannah R. Many seemingly viable products are designed and built in MIT Mechanical Engineering's senior capstone design class, 2.009, but a small fraction make it to real markets. The 2017 2.009 Orange Team is commercializing their product through the company Rhino Tools and Equipment (RTE). The product, a rotary hammer attachment that guides the chisel bit as it moves within a mortar joint, was designed with the aim of improving the repointing work done by masons on brick exteriors. Given the real constraints on a team of soon-to-be graduating students and analysis of the market and the product, a licensing business model was chosen. The licensing business model is heavily reliant on intellectual property. Thus, an extensive prior art search was carried out to determine the product's novelty. By this analysis the product is patentable. Cash flows were projected to determine a fair allocation of economic benefit in a licensing agreement; RTE should expect to receive about 4.5% royalty on revenue. Moving forward, RTE should pursue funding to complete the patent process as well as a pilot program with masons, and continue to develop its connections within the tool industry. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018; Cataloged from PDF version of thesis.; Includes bibliographical references.

Design and control of an optical fast-scanning system for silicon wafer feature measurement

Mon, 01 Jan 2018 00:00:00 GMT

Design and control of an optical fast-scanning system for silicon wafer feature measurement Taglic, Joseph C. Modem semiconductor manufacturing requires great precision for fabricating features on the surface of silicon wafers. However, testing of these wafers currently consists of selecting a subset of manufactured wafers and analyzing them with a scanning electron microscope. That process is slow and destructive to the tested wafers, and does not allow for examination of every wafer produced. This project seeks to develop an optical fast-scanning system for in-situ optical nanostructure measurement. This would be able to process many silicon wafers in a short amount of time, without destruction of the measured wafers. One key requirement for the project is thus the ability to scan a laser over the entire area of a silicon wafer in a short amount of time. Additional requirements include high precision, for accurate measurement, and adaptability to a variety of sample sizes. This thesis centers on the design and control of devices to attain these goals. Different options for design of the system are explored, with approximate scanning speed and accuracy calculated for different configurations. From these, one layout is explored in detail. The design of this system as it would be constructed is described. Driving voltage waveforms that allow for galvanometer scanning of the entire wafer area are also specified. A geometric and programmatic model of the system shows that it would be capable of detection of features greater than 1.5 mm in size in the span of 5 minutes, with speed that is easily increased. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018; Cataloged from PDF version of thesis.; Includes bibliographical references (page 38).

Modeling methylmercury in Maine's tribal meres

Mon, 01 Jan 2018 00:00:00 GMT

Modeling methylmercury in Maine's tribal meres Hoffman, Nick(Nicholas D.) Methylmercury (MeHg) concentrations in the fish of twenty Maine lakes were projected for the year 2035 under three different policy scenarios. A mechanistic model of Hg fate and transport was calibrated for Maine's environment using four parameters: volumetric outflow rate, settling velocity, burial velocity, and Hg(II) biotic solids partitioning coefficient. The model was evaluated through comparison with measured results from the year 1993. The model results showed that the strictest global Hg regulations will lead to the greatest decreases in MeHg concentration. No piscivore will be safe for frequent consumption, even under the strictest regulations in the cleanest lakes. The Wabanaki traditional-subsistence diet will continue to entail unsafe MeHg exposures. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2018; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 59-76).

Crossing educational borders : the effects of state financial aid on undocumented students' pursuit of higher education

Tue, 01 Jan 2019 00:00:00 GMT

Crossing educational borders : the effects of state financial aid on undocumented students' pursuit of higher education Guzman, Yazmin Yesenia. Currently there are twenty-two states (and the District of Columbia) that offer in-state resident tuition (ISRT) rates to undocumented youth who meet set residential criteria. As of January 2019, ten states (and the District of Columbia) have passed legislation allowing undocumented students to access state financial aid. While previous research focuses on how ISRT policies affect college entry, this study examines the effect state financial aid policies have on college enrollment. Using Current Population Survey (CPS) Merged Outgoing Rotation Groups (MORG) data from 1998-2017, I exploit the time variation in the passage of the laws to evaluate the effects of state financial aid has on undocumented students' decision to attend college. In my preferred specification, I find that state financial aid causes a statistically significant 2.7 percentage point increase in the proportion of undocumented youth enrolled in college. Additionally, men aged 21-24 experience the largest increase in college enrollment at a 5.5 percentage point increase. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: M.C.P., Massachusetts Institute of Technology, Department of Urban Studies and Planning, 2019; Thesis: S.B., Massachusetts Institute of Technology, Department of Urban Studies and Planning, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 69-72).

The physics of artificial intelligence

Mon, 01 Jan 2018 00:00:00 GMT

The physics of artificial intelligence Peurifoy, John Edward. In this thesis, I explore both what Physics can lend to the world of artificial intelligence, and how artificial intelligence can enhance the world of physics. In the first chapter I propose a method to use artificial neural networks to approximate light scattering by multilayer nanoparticles. This neural network model is experimentally shown to describe the system well, and is then further used to solve the inverse design problem and propose a generalized template for how to use neural networks to enhance numerical calculations. In the second and third chapter I explore the use of Unitary matrices in neural networks to attempt to solve the exploding and vanishing gradient problem. The norm-preserving property of unitary matrices is shown through experiments to allow neural networks to retain information over many more layers. This model achieves state of the art results on a number of toy and real world tasks. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 83-87).

Quantification of extreme event statistics in ship design

Tue, 01 Jan 2019 00:00:00 GMT

Quantification of extreme event statistics in ship design Rathore, Uditbhan S. Increased operational demands on Navy vessels extend time at sea and service life, making the accurate prediction of catastrophic failures increasingly challenging. The high value of these capital assets puts great pressure on designers and decision-makers as they work towards preventing such failures while balancing both engineering and material cost. The current method for the quantification of extreme events is direct Monte Carlo simulation supplemented by complex statistical models. When such models are not sufficiently bound by physics-based simulation, the noise of statistical uncertainty quickly overpowers the response predictions for rare events. This thesis builds on previous work at the MIT Stochastic Analysis and Non-linear Dynamics (SAND) lab for the quantification of extreme events using wave groups. By separating the event probability from the physics models, we are able to capture rare events in ship motion and loading conditions for a modest computational cost. Improvements to the wave groups methodology ensured the slope and amplitude of the incident waves reflected the waves encountered in a given wave spectrum. The remaining discussion explores the value of a near-real-time risk analysis tools in reference to ship design and ship operations, with unique application to Navy and commercial vessels. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, System Design and Management Program, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 85-86).

Naval additive manufacturing : bridging the gap between research and implementation

Tue, 01 Jan 2019 00:00:00 GMT

Naval additive manufacturing : bridging the gap between research and implementation Johnsen, David P.Nav. E.Massachusetts Institute of Technology. Additive manufacturing (AM), commonly known as three-dimensional printing, presents numerous advantages over traditional production methods, including design-to-end-use process reduction and on-demand generation of needed parts. While some companies have recently been founded with AM as their focus, many established large organizations are striving to find ways that the technology facilitates strategy execution. With its manufacturing base and requisite supply infrastructure, the military branches pose a significant opportunity for AM implementation. In particular, the U.S. Navy's continual pursuit to enhance operational readiness and advance unit self-sustainability provides a ripe environment for AM. This research sought to advance the Navy's AM implementation initiatives through the identification of candidate applications, bridging the detected gap between ashore AM research developments and the cognizance of its front-line personnel.; The resultant coordination of multiple exercises involving the Navy's operational units and field activities, culminating in two Naval AM Part-Identification Exercises, led to the discovery of over 600 AM applications that have established the Fleet's demand for AM and expedited the branch's adoption of the technology. While polymer and metal applications were identified, metallic components entail additional testing and analysis prior to shipboard use. Numerous Navy-wide efforts have stemmed from the exercises' findings, including affordability initiatives, technical data package developments, and a refined timeline for shipboard AM installation engagements. In addition, multiple avenues for the expansion of identified applications are recommended, leveraging the Fleet's existing methods of tracking material condition. An examination of the Navy's existing guidance and many of its leading AM organizations provides the context for the research efforts.; Seeking to inform these key stakeholders of considerations that must be understood prior to widespread AM utilization, an evaluation of product quality using digitally-shared print files and shipboard material distribution analyses are incorporated, providing opportunities for future development. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 197-200).

Z-source circuit breakers in naval power systems

Tue, 01 Jan 2019 00:00:00 GMT

Z-source circuit breakers in naval power systems Taft, William T.(William Theodore) New power system components and control systems are required to facilitate the U.S. Navy's move to medium voltage direct current power (MVDC) systems on future vessels. Integrating the z-source circuit breaker into a "typical" naval MVDC power system requires understanding system dynamics that may cause the circuit breaker to inadvertently energize a circuit through regenerative turn-on of the thyristor. An electrically-scaled model and a simulation model are used to characterize voltage transients that could lead to this false triggering. The results of this experiment show that these transients are within the specifications of commercially available components. Limitations in the circuit breaker's protective capabilities during turn-on transients are identified and discussed. Potential topology modifications, control schemes, and power system arrangements that provide protection across the operating range are proposed for further investigation. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 97-100).

Resilient acquisition : unlocking high-velocity learning with model-based engineering to deliver capability to the fleet faster

Tue, 01 Jan 2019 00:00:00 GMT

Resilient acquisition : unlocking high-velocity learning with model-based engineering to deliver capability to the fleet faster Rapp, Travis J.(Travis Joseph) As the nation's security needs call for a growing naval fleet, the public-private industrial base for construction and weapon system acquisition will be stressed to perform at a high level of operational excellence. While reaching the required fleet size is a major challenge, ships are the delivery vehicles for complex weapons systems whose design and production is equally critical to deliver capability that the Fleet needs. Underperformance in defense acquisitions is found to be caused by complexity, uncertainty, and risk manifested through poor requirements that are unadaptable to the changing reality of the global security landscape. This thesis hypothesizes that use of model-based engineering (MBE) will enable the needed efficiency and responsiveness.; MBE consists of digital tools motivated by the principles of traceability and high-velocity design iteration that collectively connect requirements to technical specifications in a model-centric format in contrast to the document-based form prevalent today. Given the problem of disengagement between the request for proposal and the finished product, prior case examples of using MBE elsewhere in the defense and industrial establishment show a bridge for the divide between capability requirements and technical realization. An original process-based shipbuilding production model further demonstrates how understanding effects of component changes affects overall system production. Changes in a ship's required operational capabilities, translated to technical design parameters, are mapped to production steps. The simulated performance is compared across three successive stages of construction when the change is ordered.; Results of model simulations demonstrate that similar MBE applications contribute to increased early requirement fidelity, decreases in rework through missed changes, and more rapid design iteration when the models used are properly verified and validated. Verification and validation (V&V) must be performed in a very specific environment to engender confidence in model usage through a systemic framework. One method of V&V, System Theoretic Process Analysis for Security, is illustrated using an original concept illustration of a Fictional Submarine Strategic Missile. The domain of MBE is expanded to include definition of cybersecurity requirements for a new weapon system to illustrate an iteration of model-based system design. The modeling of these requirements contributes to validated resilience upon delivery, decreasing the likelihood that cyber-physical systems will be forced to rely on time-consuming updates that delay the capability delivery. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, System Design and Management Program, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 161-165).

Use of an asymmetric propeller for unmanned underwater vehicles

Tue, 01 Jan 2019 00:00:00 GMT

Use of an asymmetric propeller for unmanned underwater vehicles Carelli, Robert Beltri. This thesis describes the development and execution of a test program to determine the suitability of an asymmetric propeller for unmanned underwater vehicles (UUV). The idea to utilize a single blade propeller had been pioneered in the past for aviation as an attempt to generate greater thrust, but was quickly abandoned. Recently, Woods Hole Oceanographic Institute reevaluated the concept for use on a UUV, but for two different objectives. The first was a possible improvement in propulsive efficiency. For UUVs meant to operate for long periods without recharging, any increase in propeller efficiency can result in more time on station. The second object was to allow for an alternate method of steering the UUV. By controlling the speed of the propeller through each revolution, the thrust at any given point can be controlled. This allows for a non-uniformly distributed thrust about the longitudinal axis of the UUV which can be used to steer the UUV. This thesis evaluated the efficiency of using such a propeller. This data was used to determine the suitability for UUVs and in which use cases an asymmetric propeller used for propulsion and steering. Due to issues during testing the control authority provided along a variety of speeds could not be determined for comparison to a traditional propeller and rudder configuration. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, System Design and Management Program, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 83).

A small palace for receptions and balls

Sun, 01 Jan 1899 00:00:00 GMT

A small palace for receptions and balls Dozier, Henrietta Cuttineau. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1899.

Evaluating the relationship between the temperature response to volcanic aerosols and climate sensitivity

Sun, 01 Jan 2017 00:00:00 GMT

Evaluating the relationship between the temperature response to volcanic aerosols and climate sensitivity Panasawatwong, Warittha. Climate sensitivity is an important concept in climate science, but its estimated value has considerable uncertainty. Some previous studies have argued for a link between the temperature response to volcanic radiative forcing and climate sensitivity. Bender et al. (2010) showed that equilibrium climate sensitivity is correlated across Coupled Model Intercomparison Project Phase 3 (CMIP3) models to the ratio of surface temperature response to top-of-atmosphere shortwave radiation response following Pinatubo, when excluding one anomalous model. In this thesis, Bender et al.'s calculation for CMIP3 models was repeated and was found to give a correlation coefficient of -0.44 (p = 0.23), which is lower than what Bender et al. found. Extension to Coupled Model Intercomparison Project Phase 5 (CMIP5) models also shows a lower correlation coefficient. Using transient climate response instead of equilibrium climate sensitivity or lower-troposphere temperature instead of surface air temperature in Bender et al.'s approach increased the correlation coefficient. Alternatively, regression of the temperature response on the shortwave radiative response and an ENSO index gave the highest correlation with climate sensitivity for a 7-year running mean surface temperature series (r = -0.65, p = 0.04) and a 7-year running mean lower-troposphere temperature series (r = -0.68, p = 0.03) based on CMIP5 models. Future work could explore the use of a transient climate response calculated from lower-troposphere temperature or a transient climate response of even shorter time-scale as alternative measures of climate sensitivity. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2017; Cataloged from PDF version of thesis. "The pagination in this thesis reflects how it was delivered to the Institute Archives and Special Collections. The Table of Contents does not accurately represent the page numbering"--Disclaimer Notice page.; Includes bibliographical references (pages 42-43).

Modeling ion mobility in solid-state polymer electrolytes

Tue, 01 Jan 2019 00:00:00 GMT

Modeling ion mobility in solid-state polymer electrolytes Chen, Songela Wenqian. We introduce a course-grained model of ion diffusion in a solid-state polymer electrolyte. Among many tunable parameters, we investigate the effect of ion concentration, ion-polymer attraction, and polymer disorder on cation diffusion. For the conditions tested, we find that ion concentration has little effect on diffusion. Polymer disorder creates local variation in behavior, which we call "trapping" (low diffusion) and "free diffusing" (high diffusion) regions. Changing ion-polymer attraction modulates the relative importance of trapping and free diffusing behavior. Using this model, we can continue to investigate how a number of factors affect cation diffusion both mechanistically and numerically, with the end goal of enabling rapid computational material design. Thesis: S.B., Massachusetts Institute of Technology, Department of Chemistry, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 31-32).

Aquadio : wearable product development

Mon, 01 Jan 2018 00:00:00 GMT

Aquadio : wearable product development Gulland, Ryan.; Libsack, Travis. Aquadio was a product design project started by a group former 2.009 students who wanted to continue learning through doing - we were interested in running our own learning experience by designing our own product. The team was organized like a start-up, using a top-down organizational structure and breaking up our team into a number of sub-teams. We started with an idea following a nominal product development process, were able to research and interview enough users to convince ourselves and others that our idea was feasible and useful. Throughout the project we honed our electrical, mechanical, software, and integration skills as a team. The product, called Aquadio, was device designed to help competitive swim teams train smarter by providing real time information and feedback to coaches and swimmers. By the end of the term we had successfully been through two iterations of our product. This work documents these design iterations and what was learned about industrial design, printed circuit board design, software user interface design, and integrating all three of these aspects. Further, through the course of the project, we justified our design decisions with responses from real world users. Finally the thesis reflects on the process that was followed. Overall, the design process we used throughout the semester was successful. The hardware challenge of creating a wearable was successfully executed - we were able to match the size constraints swimmers needed with our electronics and mechanical components. However, it was realized that electrical and mechanical design should have been more tightly coupled, and a stronger focus placed on industrial design at the earlier stages of the project. Additionally we underestimated the importance and the amount of time required to integrate all device systems for a working alpha prototype. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018; Cataloged from PDF version of thesis.; Includes bibliographical references (page 50).

Security and the Offshore Nuclear Plant (ONP) : security simulation testing and analysis of the multi-layer security system

Tue, 01 Jan 2019 00:00:00 GMT

Security and the Offshore Nuclear Plant (ONP) : security simulation testing and analysis of the multi-layer security system Conway, Jared Thomas. The ONP research team from the Nuclear Science and Engineering Department at MIT has been researching and developing the possibility of a nuclear reactor deployed on an offshore platform out to sea. Such a reactor deployed up to twelve nautical miles offshore poses a significant security risk that needs to be addressed. Through the studies of MIT graduate Vince Kindfuller, a security plan was proposed in the ICONE24-61029 paper of 2016. This research aims to investigate the effectiveness of the proposed security plan for the ONP-300 and ONP-1100 through the use of a simulation software developed by ARES Corporation, to expand on the security plan to include a response to nonviolent adversaries, and to alter the security plan and plant design as necessary to increase the effectiveness of the security configuration while limiting expenses.; Initially, different attack scenarios were investigated and four design-basis threats (DBT) were formulated based on knowledge from industry professionals. Through the use of ARES software, results indicated that the initial platform design for the ONP 300 led to major line-of-sight issues for security officers on the top deck of the plant causing performance below the minimum acceptable level. This realization led to changes in the ONP 300's security configuration and structural layout. Upon development of a platform layout that maximized security performance, a sensitivity analysis was conducted on the following aspects of the security plan: size of the adversary force, size of the guard force, and use of a hostile insider attack. The results of sensitivity analysis proved sufficient to lower the anticipated number of guard positions from 10 to 5 with 5.2 security officers per position to maintain watch at all times. This corresponds to a significant reduction in operational costs.; Sensitivity analysis also indicated that functioning radar is the key to success for security. This analysis concluded with blast analysis to determine the location of the physical barrier which should be placed about 250 m from the ONP and an overview of ONP-1100 security performance with five guard positions. The major contribution of this work is therefore two-fold: First, implementation of security-enhancing features have been accomplished at the very early stage of the ONP design when innovative features can be best identified and implemented in a cost-effective manner. Second, application of a Monte Carlo numerical tool has allowed confirmation of the effectiveness of the design to defeat a wide range of intruder scenarios under a variation of different situations proving the robustness of the security design. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, June 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 94-96).

Interaction of amphiphilic nanoparticles with structurally perturbed lipid membranes

Mon, 01 Jan 2018 00:00:00 GMT

Interaction of amphiphilic nanoparticles with structurally perturbed lipid membranes Derry, Alexander(Alexander W.) Understanding the interactions between nanoparticles and lipid membranes is important for applications such as drug delivery and membrane-protein mimetics. Perturbations such as area asymmetry and lateral tension affect these interactions by inducing various structural changes to the membranes. We use molecular dynamics simulations to demonstrate that the introduction of area asymmetry to a bilayer membrane significantly decreases the insertion latency of amphiphilic gold nanoparticles into both the densely and sparsely packed leaflets. We further demonstrate using transition state analysis that the dominant mechanisms for insertion into the dense and sparse leaflets are lipid desorption and lipid tail protrusions, respectively. These findings are supported by potential of mean force calculations showing that the energy barrier to protrusion is lower in the sparse leaflet, while that of desorption is lower in the dense leaflet. We also demonstrate that the structural characteristics of the bilayer when subject to lateral tension are similar to that observed in membranes with area asymmetry, suggesting a similar reduction in insertion latency. Further, we observe that lateral tension also increases the likelihood of nanoparticle ligands flipping across the bilayer, which is necessary for the nanoparticle adopting a stable symmetric configuration in the membrane. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 43-45).

Examining the evidence for Chthonian planets : superdense exposed exoplanet cores

Tue, 01 Jan 2019 00:00:00 GMT

Examining the evidence for Chthonian planets : superdense exposed exoplanet cores Bates-Tarasewicz, Haley. Planetary cores are of interest because they provide insight into the internal dynamics and composition of planets. By using mass-radius relationship compositional analysis, this work originally set out to look for evidence of exoplanet exposed iron cores; it stumbled, however, upon potential superdense core candidates (or "Chthonian" cores). We identify 19 potential superdense core candidates, and compare them to the Fossilized Core Theory and the Giant Impact Theory of formation. Additionally, while there are 19 superdense core candidates, they represent only 11 solar systems. We find that both theories plausibly describe the formation of these superdense candidates, and note that all candidates have very typical stars similar to our own sun. Until the mass measurements of the candidates are better constrained, further conclusions cannot be drawn, however, this new type of planet could help inform planetary formation, evolution, and interior dynamic models. Thesis: S.B., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 24-30).

Coastal urban atmospheric mercury cycling and emissions in Boston, MA

Tue, 01 Jan 2019 00:00:00 GMT

Coastal urban atmospheric mercury cycling and emissions in Boston, MA Rutkowski, Emma. This study aims to contribute to the body of knowledge regarding mercury emissions by reporting on a coastal, urban setting subject to inputs from both anthropogenic and oceanic reservoirs, in order to improve related policy decisions. Mercury can have serious health and ecological consequences, but the chemistry, transport and deposition of gaseous elemental mercury (Hg0) are still not well understood. Estimates of anthropogenic emissions also remain uncertain. To better constrain urban- and regional-scale chemistry and emissions in a specifically coastal environment, concentrations of Hg0 were measured at an urban site in Boston, MA from Aug 2017 to Sept 2018. The recorded concentrations were compared against supplementary records of several additional pollutants and meteorological variables. Concentrations in Boston were found to be relatively low, but follow diurnal and seasonal trends previously observed in other sites in the United States driven by meteorology. Further, back-trajectory and potential source contribution function analysis revealed oceanic re-emission of legacy deposits is a major input of Hg0 to the Boston area, but no influence from specific large anthropogenic point sources was discernible in the data. A one box model was developed to represent the physical processes controlling Hg0 concentrations in Boston in order to replicate concentrations, capture the difference in concentrations from land and ocean sources, and estimate both anthropogenic and oceanic emissions. Results from the box model analysis show the sensitivity of local Hg0 concentrations to varying assumptions of mixing, background flux, meteorology, and emissions, and indicate that oceanic emissions and anthropogenic emissions are likely both higher than current estimates. The results of this study indicate the ocean plays a major role in Hg0 cycling in coastal areas and provides motivation for further improvement of models to better capture local sources and cycling. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2019; Page 57 blank. Cataloged from PDF version of thesis.; Includes bibliographical references (pages 48-52).

Sulfurizing and selenizing metal films in ultra-high vacuum by hydride gas kinetic control

Tue, 01 Jan 2019 00:00:00 GMT

Sulfurizing and selenizing metal films in ultra-high vacuum by hydride gas kinetic control Luhman, Xavier D. Molecular beam epitaxy (MBE) is an important, well-established method for creation of thin films. The addition of gaseous sources of hydrogen sulfide and hydrogen selenide is not currently a well-documented or common modification to such systems. While the thermodynamics of using such sources for the production of various chalcogenide thin films are favorable, the actual results thus far do not demonstrate the desired outcome. This indicates that the kinetics of the desired reactions are inhibiting the process. Compared to oxygen, reactions involving sulfur and selenium are slow. In order to ensure that the hydride gases have the opportunity to react as desired, it is necessary to keep the system free of oxygen and to maximize the collisions of gas molecules with the substrate. The first requirement should be achieved simply by using MBE for the process. The second requirement is not provided for in a typical MBE system. Thus, modifications are necessary to increase the reaction rate of the gases, namely by extending the source lines to be closer to the substrate. This thesis addresses the design process for tubing inserts in an existing MBE system. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2019; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (page 30).

Risk based decision making for the deferment of U.S. Navy submarine maintenance

Tue, 01 Jan 2019 00:00:00 GMT

Risk based decision making for the deferment of U.S. Navy submarine maintenance Washko, J. Matthew(Jon Matthew) Maintenance of United States Navy submarines is a complex set of operations comprised of scheduling, budgeting, and executing a continuous stream of work across multiple vessels in the same maintenance facility year after year. Local personnel are involved in the details of the day to day operations and focus deeply on today and tomorrow, with little bandwidth to focus on larger, systemic issues with impacts far removed from today. The addition of fluctuating annual funding levels, a younger workforce, and the pressures to meet national defense requirements add complexity and compound the pressure to mortgage tomorrow for today by deferring work without regards to its later impact. Recently, the maintenance community has begun to invest time and resources in these larger, systemic issues. This thesis investigates the impacts of deferred maintenance actions on the timely completion of submarine maintenance periods by analyzing data from 50 refits executed over a decade at Trident Refit Facility in King's Bay, Georgia. The results of this thesis are best understood in three parts: the impact of deferred maintenance actions on submarine refit on-time completions, the development of a technical, risk-based deferment decision tool, and the possible application of deferring or canceling certain maintenance items as a way to reduce the maintenance workload across the fleet. The first part shows the quantitative analysis of the data demonstrating that deferred maintenance actions are not having any negative impacts to on-time schedule execution. The second part shows how through technical analysis and application of a probability and consequence risk framework, deferment decisions can be analyzed to ensure that only low-risk work is being deferred. And finally, an application of that same framework can be made across the fleet to lower the maintenance backlog. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 49).

A launch and recovery system for integrating unmanned ocean vehicles onto surface platforms

Tue, 01 Jan 2019 00:00:00 GMT

A launch and recovery system for integrating unmanned ocean vehicles onto surface platforms Strouse, Casey L. Unmanned vehicles (UxVs) are becoming more prevalent across all domains. As UxV technology improves and their operations become more essential to mission success, the challenge of integrating these vehicles onto current surface platforms becomes increasingly more important to solve. Surface ships are designed to be adaptive and meet the changing requirements of their operational environment over their 25-plus year life. However, the majority of the current surface fleet was not designed from the beginning for launch and recovery of unmanned ocean vehicles and must be retrofitted to support unmanned vehicle operations. While integration of UxVs will be limited by the size of the host platform, their integration should not be limited due to the inability to safely launch and recover them. This paper will analyze current manned launch and recovery systems across all naval surface platforms and present recommendations for improving these systems to be more adaptive to launching both manned and unmanned ocean vehicles. Specifically, this research will focus on minimizing the heave motions exhibited by the vehicle during launch and recovery. To achieve minimized heave motions and improve operational performance, an analysis was conducted to determine the feasibility, performance, and safety benefits of integrating an active heave compensating winch into the system. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 64-65).

Simulation-guided lattice geometry optimization of a lightweight metal marine propeller for additive manufacturing

Tue, 01 Jan 2019 00:00:00 GMT

Simulation-guided lattice geometry optimization of a lightweight metal marine propeller for additive manufacturing Dagres, Ioannis. Additive manufacturing (AM) is one of the most promising emerging technologies for advanced mechanical systems. When compared to conventional manufacturing processes, AM offers major advantages in production of complex components, enhanced performance, material savings, and supply chain management. These advantages are driving a shift towards AM in marine industry, which is highlighted by recent relative publications of the American Bureau of Shipping (ABS) and others. This thesis focuses on the design of an exemplary marine propeller that leverages the advantages of AM through simulation-guided design of an internal lattice structure. Specifically, a B-series Wageningen three-blade propeller model, provided by Naval Warfare Surface Center (NSWC) Carderock, was used as a baseline. Its open water loading conditions were calculated numerically using OpenFOAM®, a computational fluid dynamics (CFD) software. The CFD results were verified using the provided test data, the thrust and torque coefficients differed by a maximum of 2.7%. The derived loads were introduced to the Finite Element Analysis (FEA) based optimization utility in Autodesk® Netfabb Ultimate, in order to identify the optimum lattice geometry for this application. The design limitations were dictated by the material (316SL stainless steel), the metal additive manufacturing process, and the propeller outer geometry.A variety of lattice infill designs were generated to create a design trade space and conclude to the most appropriate design for this application. The design with the best performance was a hexagonal grid lattice with 1 mm wall thickness, which was prescribed as a manufacturing constraint (i.e., the thinnest wall). The material volume was reduced by more than 50%, while exhibiting a satisfactory safety factor based on the material properties and the simulated loads. Sections of the propeller were prototyped by Desktop Metal Studio System[superscript TM]. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 149-153).

The nature and effects of hiring practices in the construction industry

Thu, 01 Jan 1959 00:00:00 GMT

The nature and effects of hiring practices in the construction industry Sampson, Richard Lee. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Civil and Sanitary Engineering, 1959.; Includes bibliographical references (leaves 51-53).

Response of a simple span highway bridge to dynamic loading

Thu, 01 Jan 1959 00:00:00 GMT

Response of a simple span highway bridge to dynamic loading Rossow, Edwin C. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Civil and Sanitary Engineering, 1959.; Includes bibliographical references (leaves 66-68).

Comparative study of structural aluminum and steel

Thu, 01 Jan 1959 00:00:00 GMT

Comparative study of structural aluminum and steel Rodriguez-Andrade, J. Antonio(Jesus Antonio) Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Civil and Sanitary Engineering, 1959.; Includes bibliographical references (leaf 110).

Drying shrinkage of Portland cement mortar

Thu, 01 Jan 1959 00:00:00 GMT

Drying shrinkage of Portland cement mortar Priluck, Herbert M. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Civil and Sanitary Engineering, 1959.

Proposed centralized traffic control on the Boston and Maine : a study of the feasibility of a centralized traffic control system on the Boston and Maine Railroad between Springfield and Greenfield, Massachusetts

Thu, 01 Jan 1959 00:00:00 GMT

Proposed centralized traffic control on the Boston and Maine : a study of the feasibility of a centralized traffic control system on the Boston and Maine Railroad between Springfield and Greenfield, Massachusetts Prentiss, Arthur T. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Civil and Sanitary Engineering, 1959.

An investigation of the Ibanez Dynamometer

Sat, 01 Jan 1949 00:00:00 GMT

An investigation of the Ibanez Dynamometer Sprague, Donald R. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Civil Engineering, 1949.

Low-cost reinforced-concrete housing employing prefabricated plywood panels

Sat, 01 Jan 1949 00:00:00 GMT

Low-cost reinforced-concrete housing employing prefabricated plywood panels Roberts, Robert J. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Civil Engineering, 1949.; Bibliography: leaves 67-69.

A laboratory investigation of the shearing strength of fine sands as a function of saturation

Sat, 01 Jan 1949 00:00:00 GMT

A laboratory investigation of the shearing strength of fine sands as a function of saturation Lowry, Emmert M.; Reusswig, Frederick W. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Civil and Sanitary Engineering, 1949.; Bibliography: leaf 41.

Proposed centralized traffic control installation and second main track retirement on the Boston And Maine Railroad

Sat, 01 Jan 1949 00:00:00 GMT

Proposed centralized traffic control installation and second main track retirement on the Boston And Maine Railroad Lamphier, Thomas J. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Civil and Sanitary Engineering, 1949.; Bibliography: leaf 24.

Design and testing of an autonomous mothership for surface vehicle swarm docking

Tue, 01 Jan 2019 00:00:00 GMT

Design and testing of an autonomous mothership for surface vehicle swarm docking Freeman, Andrew(Andrew John) The field of marine autonomous systems has blossomed over the past several decades yet much remains to be explored. One important focus area gaining increased attention in this domain is the understanding and development of cooperative groups of vessels, known as swarms. Using simple behavioral rule sets, these systems of marine vehicles can work together in many ways including traveling in a "flock" or forming a perimeter around an area of interest. In many cases, however, the vehicles encounter limitations with respect to their capacity to carry a certain resource. This can manifest itself in the form of finite electrical energy, cargo-carrying capacity, or the need to replenish a swarm vehicle's deployable payloads. In all of these situations, there are many useful scenarios where the addition of a "mothership" can improve overall system performance. This thesis elucidates the essential parameters for the design of such a mothership and considerations for docking the two vehicles together autonomously. Focus is placed on maintaining the mothership lightweight, compact, and low cost to ensure the results are usable by a broad audience and that the principles are shown to apply to the widest array of designs. A methodology and tools are presented herein to prepare future designers for creating similar systems. These include a theoretical analysis of the finite resource problem and how to leverage parameter relationships to determine design specifications for the mothership. A computational analysis of mother-daughter relative motions in waves follows which validates that the hullform characteristics support reduced complexity at the docking bay. Finally, a prototype developed by the author using the proposed methodology is detailed and experimental results are presented which highlight important considerations contributing to the success of autonomous mothership docking. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 129-131).

Analyzing recent latitudinal and seasonal changes in simulated atmospheric temperatures from a global chemistry-climate model

Tue, 01 Jan 2019 00:00:00 GMT

Analyzing recent latitudinal and seasonal changes in simulated atmospheric temperatures from a global chemistry-climate model Benjamin, Jordan T. Recent work by Santer et al. (2018) in Science examined the usefulness of the latitudinal structure and seasonal behavior of warming for fingerprinting anthropogenic climate change using satellite data and the CMIP5 multi-model ensemble over 1979-2016. They identify the first seasonal fingerprint in the northern hemisphere annual cycle and structure of warming, but do not specify what forcing agent (e.g. ozone, soot, or greenhouse gases) is responsible for causing it. We further probe this phenomena using 3 ensembles-of-opportunity over 1955-1979 and 1995-2024 of the Whole Atmosphere Community Climate Model version 4 (WACCM4), one of the world's few best fully coupled interactive chemistry-climate models. While our ensembles' construction covers limited time periods, it has the advantage of avoiding the effects of El Chichón (1982) and Pinatubo (1991), which are difficult to capture in models and have different drivers (volcanic) than the ones of interest here. The key findings of this research are that added greenhouse gas forcings nearly fully determine the latitudinal structure of warming and change in the amplitude of the annual cycle, that WACCM4 does a much better job than the CMIP5 multi-model ensemble of predicting the magnitude and latitudinal structure of climate change, and that tropical expansion and a poleward shift of the jet may drive the key subtropical features Santer observed. Interactive chemistry is not found to be a defining factor in representing the rate and structure of warming in CMIP5, and is certainly much less important than other details of model construction. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 28-29).

Field measurements of deposition mode ice nucleating particles at Puy de Dôme/

Tue, 01 Jan 2019 00:00:00 GMT

Field measurements of deposition mode ice nucleating particles at Puy de Dôme/ Goodell, Megan M. Ice nucleating particles are a critical aspect of the atmosphere to study due to their importance for cloud processes, weather, and climate. This thesis discusses deposition mode ice nucleating particle concentrations measured using the SPectrometer for Ice Nuclei at Puy de Dôme, France. These concentrations were most strongly dependent on source of the sampled air mass; meteorology and concentrations of gas phase species were poor predictors of INP abundance. Of particular interest is the distinct difference observed in activated fraction of particles between air masses from continental, marine, and new particle formation event sources, suggesting formation mechanism and particle chemistry as important factors in a particle's ability to nucleate ice. Analysis of new particle formation events also indicates that secondary organic aerosols derived from isoprene could be an important source of ice nucleating particles to consider. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 21-24).

Water and carbon flux responses to soil moisture pulses in the Western United States

Tue, 01 Jan 2019 00:00:00 GMT

Water and carbon flux responses to soil moisture pulses in the Western United States Chulakadabba, Apisada. In this study, the relationships among plant water and carbon flux responses to soil moisture resource pulses in semi-arid lands of the Western United States were diagnosed. Measurements from twelve AmeriFlux tower (in situ) and SMAP (satellite) sites across the region were used to estimate relationships between carbon flux and resource availability. The differences between respiration and photosynthesis dominant regimes and the transition from water to energy limited regimes could be observed. Water use efficiency of plants in the regions was estimated to be around 5.0 grams of carbon dioxide per 1 kilograms of water when water was excess. Response patterns were shared among the similar ecosystems. The role of water and carbon flux response to intermittency resource availability could lead to improved estimation of land carbon budgets. Thesis: S.B., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 37-38).

Mechanical reinforcement of hydrogels via bio-inspired mineralization

Tue, 01 Jan 2019 00:00:00 GMT

Mechanical reinforcement of hydrogels via bio-inspired mineralization Saouaf, Olivia(Olivia MIchelle) Nanocomposites made of polymer networks and mineral particles lend great mechanical integrity to biological materials. This study aims to imitate these natural materials by creating a hydrogel mineralized with magnetite particles. We create a hydrogel of polyallylamine crosslinked via tannic acid molecules. Crosslinking is dependent upon pH as well as amounts of periodate and tannic acid. The addition of greater amounts of tannic acid and periodate at higher pH creates a more strongly crosslinked network, shown through rheological measurements as the gel's shear modulus increases. Upon mineralization, a 10²-10³ order of magnitude increase in shear modulus occurs. This work elucidates a method for nanocomposite hydrogel synthesis that creates a mechanically strong biocompatible material for future applications in bio-interfacing technology and drug delivery. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 25-26).

Natural carbonaceous materials for use in transparent Joule heaters

Tue, 01 Jan 2019 00:00:00 GMT

Natural carbonaceous materials for use in transparent Joule heaters Hasbach, Ximena. Natural carbonaceous materials have the potential to be used in a new class of more economically and environmentally sound electronic devices due to their tunable conductivity as well as robust mechanical and thermal properties. This study aims to explore the potential of steam cracker tar (SCT), a byproduct of ethylene production, for use in conductive applications, specifically transparent Joule heaters. The SCT was made into thin films using both rod-rolling and spray-coating methods. After the superior uniformity of the rod-rolled films was observed, a 2 laser cutter was used to anneal the rod-rolled films with the intention of increasing their sp² content and thus improving their conductivity. First the power and then the z-defocusing of the laser were varied, and the ability of the resulting films to heat was tested with an applied voltage. To test the conductivity and heating capabilities of the annealed SCT films, 60 volts were applied, the current measured, and the number of degrees heated measured with a thermal camera software. A combination of Raman spectroscopy and profilometry was used to characterize the films. The film with the best heating capabilities was found to be the one annealed with 8% laser power and 0.2 inch z-defocus. This film was observed to heat to 35 degrees Celsius, and was demonstrated to efficiently de-ice a frozen sheet of tempered glass. Future work in this study will focus on finding ways to improve conductivity in SCT films with better transparency. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 35).

Investigation of physical and chemical properties of scandium oxide using a thermal imaging furnace

Tue, 01 Jan 2019 00:00:00 GMT

Investigation of physical and chemical properties of scandium oxide using a thermal imaging furnace Wu, Mindy(Mindy Li) Properties of high melting temperature materials have yet to be well-established due to the experimental difficulty of making such measurements. One such material for which properties are not reported are scandium oxide, a material of recent interest due to the wide range of technological applications it has and the enormous development potential of scandium metal. The absence of such knowledge is a limiting factor for its further application in high temperature and molten environments. An experimental study was performed to determine the density and surface tension of scandium oxide at varying temperatures using the pendant drop method in the thermal imaging furnace (TIF), which is uniquely suited to making containerless studies of molten materials. From 2781 to 2962°C, the density was found to range from 2.92 ± 0.02 to 3.23 ± 0.13 g/cm³ and the surface tension from 697.3 ± 13.1 to 765.7 ± 7.02 mN/m. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2019; "June 2019." Cataloged from PDF version of thesis.; Includes bibliographical references (pages 64-68).

Design and construction of a propeller open water testing apparatus and testing of a stereolithography 3D printed model propeller

Tue, 01 Jan 2019 00:00:00 GMT

Design and construction of a propeller open water testing apparatus and testing of a stereolithography 3D printed model propeller Hentschel, William R.(William Ryan) This thesis describes the design and construction of a propeller open water testing apparatus for educational and experimental use at MIT. This test apparatus was built as an inexpensive alternative to conducted in-house model scale marine propeller testing. A complimentary study was conducted to explore the process of manufacturing a model propeller using additive manufacturing. A propeller open water test apparatus, commonly referred to as a test boat, is used to measure the performance of marine propellers in uniform flow. The test boats performance was validated using a Wageningen B-series aluminum propeller as a benchmark. The test boat measured the open water performance of this benchmark within a small percentage of error. The practicality of using additive manufacturing to produce a model propeller was explored by manufacturing and testing a 3D printed replica of the benchmark propeller. The replica propeller was manufactured using a benchtop stereolithography 3D printer. The open water characteristics of the replica were measured and compared to the benchmark propeller. Results of this testing revealed some limitations of 3D printed model propellers, such as size constraints and imprecision of propeller blade geometry. This research has provided MIT students with an inexpensive method to conduct preliminary marine propeller testing and offers in-sight into the use of additively manufactured model propellers. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 85).

Development of a physiologically accurate 3D blood-brain barrier hydrogel model

Tue, 01 Jan 2019 00:00:00 GMT

Development of a physiologically accurate 3D blood-brain barrier hydrogel model Kioulaphides, Sophia. The blood-brain barrier (BBB) is a tightly interconnected network of cells that creates a semi-permeable barrier between the central nervous system and the rest of the human body, taking in nutrients and blocking/excreting waste/potentially toxic chemicals from the brain, maintaining the brain's health and stability. When toxins are able to make it past the BBB, the BBB is degraded and can lead to further neurodegenerative disorders such as Alzheimer's and dementia. In order to better understand the structure of the BBB, the causes of its degradation, and potentially curing diseases, drug delivery experiments have been performed on the brain. However, since the drug carriers tested often may be perceived as toxins to the brain due to their large size or composition, researchers have leaned towards making in vitro 3D hydrogel models of the BBB. This project aims at making an in vitro 3D BBB hydrogel model that is physiologically accurate as possible. Components in the biological BBB were researched and these gels containing these polymers were created in order to determine if homogenous gels could be made and if they would support healthy human astrocyte (HAst) growth. Numerous compositions of hyaluronic acid, collagen IV, and a crosslinker were found to both create homogenous gels and support healthy astrocyte growth. Additionally, the processing steps for making these hydrogels was optimized further in order to ensure as much homogeneity as possible in the final gel. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2019; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 38-39).

Antiperovskite crystal growth

Tue, 01 Jan 2019 00:00:00 GMT

Antiperovskite crystal growth Eiler, Stephanie L. Research towards the implementation of solid state electrolyte in lithium ion batteries is necessary to increase the energy density of such devices. This technology is imperative for the adoption of sustainable technology such as electric vehicles. The study of antiperovskites is vital for success of solid state electrolyte. Antiperovskites have been shown to have high ionic conductivities in literature, making it an attractive area of study. Single crystals of this structure are necessary to fully identify the mechanism of ion conduction in antiperovskite. X-ray photon correlation spectroscopy on a single crystal would provide clear data that could help determine the mobility of various defects through the antiperovskite lattice. Characterization of defect mobility would allow for the better design of antiperovskites as a solid state electrolyte by providing parameters for how the material can be altered for higher ionic conductivity.; Experiments show that Li₂OHCl is an antiperovskite possibly capable of congruent melting, making it a possible candidate for single crystal growth through the Bridgman method. With this rational, the PARADIM Bulk Crystal Growth Facilities at Johns Hopkins University were utilized to attempt this type of crystal growth. Additional crystal growth experiments were conducted by simply slowly cooling the material in box furnaces with the notion that this would promote large grain growth. Samples created using these methods were examined using optical microscopy and Laue diffraction. Crystals grown in PARADIM Bridgman furnaces were shown to have some grains that are roughly two mm across. From these attempts at crystal growth, recommendations for improved Li₂OHCl crystal growth have been identified. Phase transformations in the material presented clear challenges in crystal growth by offering an opportunity for twinning to occur in the crystal as it cooled.; In addition to this, the volume change during solidification and the thermal coefficient of expansion was such that very slow cooling rates would be necessary for single crystal growth. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2019; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 45-46).

Hierarchical control of hydrogel dynamics via choice of ligand chemistry

Tue, 01 Jan 2019 00:00:00 GMT

Hierarchical control of hydrogel dynamics via choice of ligand chemistry De Quesada, Felipe Alexander. Hydrogel networks formed via dynamic metal-coordination chemistry display remarkable mechanical properties, such as self-assembly, stimuli-responsiveness, and the ability to self-heal. Recent efforts have looked into expanding the prevailing knowledge of metal ion-coordination chemistry to nanoparticle-ligand interactions, with the goal to further provide rational control over the mechanical properties of the gel. Although studies have focused on varying nanoparticle size and shape, little work has been conducted to understand how the choice of ligand chemistry affects the macroscopic gel dynamics. This thesis investigates the orthogonal control of macroscopic gel dynamics via variations in the choice of ligand chemistry. More specifically, 4-arm poly(ethylene glycol) (4-PEG) functionalized with either catechol, nitro-catechol or terpyridine end groups are crosslinked with either iron(III) ions (i.e. Fe³⁺) or ferrite nanoparticles (i.e. Fe₃O₄). Rheological and spectroscopic measurements show that the macroscopic dynamic behavior of gels can be controlled orthogonally from the choice of metal chemistry and polymer architecture via choice of ligand chemistry and that this choice can be guided by the activation energy barrier for the dissociation of the metal-ligand complex. In addition, the range of accessible gel dynamics can be further expanded by adjusting the pH of the gel and combining the choice of ligand chemistry with other design parameters. These findings allow to create tailor-made hierarchical relaxation moduli in soft structural matter and further adapt the dynamic behavior to any given application. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2019; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (page 36).

The prediction of amplitude of oscillation in vacuum tube [fari,jam,c

Sun, 01 Jan 1933 00:00:00 GMT

The prediction of amplitude of oscillation in vacuum tube [fari,jam,c Fink, Donald G. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering, 1933.; Includes bibliographical references.

A study of the effects of velocity profile development and polyethylene oxide addition on liquid jet stability

Sun, 01 Jan 1967 00:00:00 GMT

A study of the effects of velocity profile development and polyethylene oxide addition on liquid jet stability Dotson, James William. Massachusetts Institute of Technology. Dept. of Chemical Engineering. Thesis. 1967. B.S.; Bibliography: leaf 31.

Interfacial turbulence arising from surface tension effects.

Sun, 01 Jan 1967 00:00:00 GMT

Interfacial turbulence arising from surface tension effects. Heines, Henry. Massachusetts Institute of Technology. Dept. of Chemical Engineering. Thesis. 1967. B.S.; Bibliography: leaf 60.

A study of the Weston hydro-electric plant at Skowhegan, Maine

Thu, 01 Jan 1925 00:00:00 GMT

A study of the Weston hydro-electric plant at Skowhegan, Maine Butler, Theodore Herrick. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering, 1925.; Includes bibliographical references.

A study of storage effects on the Connecticut River at fifteen mile falls

Thu, 01 Jan 1931 00:00:00 GMT

A study of storage effects on the Connecticut River at fifteen mile falls Holden, Donald A. Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1931.; Appendix contains numerous pamphlets.

An index of composite productivity

Sun, 01 Jan 1933 00:00:00 GMT

An index of composite productivity Holt, Robert Gerald.; Laird, William Winder.; Van de Water, Charles Franklin. Thesis (B.S.)-- Massachusetts Institute of Technology, Dept. of General Engineering, 1933.

An investigation of the diamond impression method for measuring tool wear

Tue, 01 Jan 1952 00:00:00 GMT

An investigation of the diamond impression method for measuring tool wear Adams, Robert B.(Robert Bernard); Goode, Robert E. Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mechanical Engineering, 1952.; Bibliography: leaf 44.

Electron density variation with incident power in a steady state microwave discharge.

Mon, 01 Jan 1968 00:00:00 GMT

Electron density variation with incident power in a steady state microwave discharge. Terry, Robert Eli. Massachusetts Institute of Technology. Dept. of Physics. Thesis. 1968. B.S.; Bibliography: leaf 47.

Paradox East and West: some parallels between Zen Buddhism and western philosophy.

Mon, 01 Jan 1973 00:00:00 GMT

Paradox East and West: some parallels between Zen Buddhism and western philosophy. Plzak, Richard Francis. Massachusetts Institute of Technology. Dept. of Humanities. Thesis. 1973. B.S.; Bibliography: leaves 96-98.

Reactor core meltdown containment for offshore applications.

Mon, 01 Jan 1973 00:00:00 GMT

Reactor core meltdown containment for offshore applications. Bowman, Frank Lee. Massachusetts Institute of Technology. Dept. of Ocean Engineering. Thesis. 1973. M.S. (Also M.S. in Nuclear Engineering.); Bibliography: leaves 152-157.

Plastic analysis of dented tubes subjected to combined loading

Fri, 01 Jan 1988 00:00:00 GMT

Plastic analysis of dented tubes subjected to combined loading Suh, Myung Sung. Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1988.; Title as it appeared in M.I.T. Graduate List, June 1987: Plastic analysis of dented tubes under combined loading.; Bibliography: leaves 194-198.

Biomimetic improvement of the maneuvering qualities of unmanned underwater vehicles

Tue, 01 Jan 2019 00:00:00 GMT

Biomimetic improvement of the maneuvering qualities of unmanned underwater vehicles Trakht, Yuri. In recent years, biomimetics has been used as a source of inspiration to improve the performance of engineered systems in several disciplines. In this thesis, we emulate the function of the retractable dorsal fins in tunas to improve the maneuvering performance of a typical autonomous underwater vehicle, the REMUS 100 AUV. We are introducing dorsal-like fins on the AUV that can be erected to alter its maneuvering hydrodynamic coefficients, and hence affect the transient and steady-state turning response. In order to study systematically the effect of adding dorsal fins, we built a six degrees of freedom simulation model of the REMUS AUV. The model included body and rudder lift forces and moments, added mass forces and moments, gyroscopic and centrifugal forces, drag forces and moments, and body forces and moments such as buoyancy and gravity terms. To target the horizontal plane maneuvering characteristics, we reduced the model to a 3 DOF simulation, allowing the dorsal fin to vary in area, location along the length of the AUV, as well as having a turning angle with respect to the REMUS x-axis. We find that the addition of the fin can improve the performance, as measured by the radius of turning and rate of turning, moderately only when placed ahead of the center of gravity. However, when the dorsal fin is also allowed to rotate in the opposite direction that the rudder, substantial improvement in maneuvering performance is noted, increasing the turning rate up to 25%. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (page 70).

Spectral analysis of integrated F-center feedback dosimeter

Mon, 01 Jan 2018 00:00:00 GMT

Spectral analysis of integrated F-center feedback dosimeter Schumaker, Daniel(Daniel C.) Proton therapy has yet to implement an in-vivo, real-time, fault-tolerant integral dosimeter. Proposed in this thesis is a conceptual dosimeter to meet such requirements, relying on the radiation-stimulated production of F-centers in alkali halide salts. F-centers are optically active vacancies in the cation-anion lattice filled with a lone electron. These vacancies cause dimming bands in broad-band illumination of the crystal, and the vacancies increase in number in a proportional fashion to the dose received. The experiment proposed here will serve both to measure the dimming quality of various alkali halide salts as well as their decay rate in the dark at room temperature. Once performed, this experiment will demonstrate the feasibility of correlating dose to a real-time color measurement of an implanted alkali halide crystal in a patient undergoing proton radiotherapy. Thus far no such experiments have been performed, however the experimental assembly outlined herein is nearly fully constructed and nearly ready for experimentation upon time of completing this thesis. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2018; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 48-53).

The design and implementation of NewsPeek : an interactive news gatherer for future communications systems

Mon, 01 Jan 2018 00:00:00 GMT

The design and implementation of NewsPeek : an interactive news gatherer for future communications systems Labalme, Fen(Fen née Steven Ford) This thesis describes work done at the Architecture Machine Group at MIT in the field of Media Technology. An interface to a information intensive network is discussed and proposed. A prototype implementation of such an interface has been designed and built and is currently being used as a test bed for the development of a future Home Communication Set . This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (page 34).

Quantum diamonds : a discussion of the chemistry, materials science, physics and applications of ternary (Cu-In-S) nanocrystals

Tue, 01 Jan 2019 00:00:00 GMT

Quantum diamonds : a discussion of the chemistry, materials science, physics and applications of ternary (Cu-In-S) nanocrystals Romero, Trevor Walton. Quantum dots (QDs) are nanometer-sized crystallites of inorganic semiconductors with tunable optoelectronic properties, which has led to a variety of real-world applications beginning in the 1980s, ranging including electronic displays, solar cells, and quantum computers [(Lee, SID), (Tang, Nature Mater.), (Puri, Phys Rev. B)]. However, most high-quality QD materials explored to date have been limited for large-scale application due to toxicity concerns or difficult-to-scale preparative methods. This thesis explores the synthesis and properties of colloidal nanocrystals composed of the non-toxic semiconductor copper indium sulfide (CulnS₂). We report an improved core nanoparticle synthesis with unique compositional control, a rationally-designed precursor for the synthesis of high-quality CulnS₂/ZnS nanocomposites, and describe the dependence on the photophysical properties of CulnS₂/ZnS on core CulnS₂ elemental composition. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2019; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 33-34).

Umplementation of Mathematica® interface for DOME (Distributed Object-based Modeling Environment)

Mon, 01 Jan 2001 00:00:00 GMT

Umplementation of Mathematica® interface for DOME (Distributed Object-based Modeling Environment) Lee, Kathleen Jheehye, 1978- Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.; Includes bibliographical references (p. 23).

Three-dimensional magnetic domain imaging with polarized neutrons

Sun, 01 Jan 2017 00:00:00 GMT

Three-dimensional magnetic domain imaging with polarized neutrons Delmore, Alexandra R Application and fundamental understanding of magnetic materials requires knowledge of their properties and phase diagrams, which depend on the structure and dynamics of magnetic domains. Current techniques for studying magnetic domains are limited to imaging near-surface magnetic structure. Techniques for investigating bulk magnetic structure are under development, particularly for applications in electronics and superconductivity. This study investigates the feasibility of observing bulk magnetic domain structure using polarized neutron imaging and tomography. Polarized neutrons are advantageous for studying internal magnetic structure because they penetrate materials, and their spin-polarizations are sensitive to magnetic fields. This study experimentally tested the depolarization of neutrons in five different materials with known magnetic order using PONTO, an instrument at Helmholtz-Zentrum Berlin (Germany) that uses a polarization-sensitive filter and analyzer to measure neutron depolarization in magnetic samples. Magnetic structure was observed when samples were subjected to magnetic fields to increase magnetization, and to cooling beneath the Curie temperature. Samples measured at zero field and room temperature randomly depolarized the neutron beam because their domains are smaller than the resolution of PONTO. Successful observation of magnetic effects indicates the promise of polarized neutron imaging for studying bulk magnetic domain structure; however, further development of imaging methods is necessary for understanding the connection between neutron depolarization and domain structure. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 36-38).

The effects of thermal history and degree of cross-polymerization on the thermochromic behavior of diacetylene-containing polyesters

Sat, 01 Jan 1994 00:00:00 GMT

The effects of thermal history and degree of cross-polymerization on the thermochromic behavior of diacetylene-containing polyesters Stengel, Kelly Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1994.; Includes bibliographical references (leaves 32-33).

A study of the folding paper box industry : with particular reference to factors influencing size and expansion

Sat, 01 Jan 1949 00:00:00 GMT

A study of the folding paper box industry : with particular reference to factors influencing size and expansion Bezark, Leonard; Krinsky, Jerome D; Salz, Jay S Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Business and Engineering Administration, 1949.; MIT copy bound with: The radarange for home use : a market evaluation / Donal Laurence Botway and Gerald Daniel Bernstein. 1949.; Bibliography: leaf 134.

An emittance scanner for high-intensity, low-energy ion beams

Mon, 01 Jan 2018 00:00:00 GMT

An emittance scanner for high-intensity, low-energy ion beams Corona, Jesus, S.B. Massachusetts Institute of Technology My work in this thesis is a contribution toward the IsoDAR experiment, which aims to test the sterile neutrino hypothesis. In the IsoDAR experiment, neutrinos are generated by a 60 MeV proton beam impinging on a 9Be target and diffusing through 7 Li. This results in 'Li which beta decays, thereby producing an electron-antineutrino beam. To overcome space charge limitations, H+ is accelerated instead of protons. Acceleration is accomplished by a cyclotron, and the beam injected into the cyclotron needs to have a low emittance (a figure of merit for the beam quality). This is where the need for a way to measure our beam's emittance arises. This thesis covers the process of designing, fabricating, assembling, and commissioning an emittance scanner. The main challenges I faced were the high-intensity of the beam and a need for high precision. I designed an emittance scanner using CAD software. Its parts were then machined in MIT's Central Machine Shop and subsequently built and installed into vacuum. As of now, preliminary commissioning of the scanners has begun with a few initial scans already performed. The scan Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 53-54).

Influence of gene expression gradients on positional information content in fly embryos

Mon, 01 Jan 2018 00:00:00 GMT

Influence of gene expression gradients on positional information content in fly embryos Hastewell, Alasdair The concept of positional information was introduced to qualitatively explain how individual cells are involved in forming patterns. Recent experimental and theoretical developments have made studying specific biological systems in a quantitative manner possible using the framework of positional information. Much previous work has focused on using the full gene expression profiles when calculating the available positional information. In an attempt to simplify the model a discretized version, where the gene expression profiles are simplified to a binary system, was proposed. Binarizing, however, results in a significant loss of information over using the full profiles. The question remains how coarsely can we discretize the full model without losing essential positional information. Recent work has shown the importance of concentration gradients in impacting the folding of proteins during embryonic development. Based on this work we posit that the gradients of gene profiles might be an important addition to the discretized model. Using data provided by the Gregor lab at Princeton University we test this hypothesis on the gap gene network of Drosophilia embryos. In order to implement the addition of gradients to the positional information requires producing an algorithm that can efficiently take meaningful derivatives of noisy data, which is done using Chebyshev interpolation. An adaptation of Monte Carlo methods to find maxima of multidimensional functions is also implemented. We find that the derivatives can account for over one bit of the information lost by the discretization process. Allowing the cells to locate themselves with an average precision close to one internuclear spacing. This suggests that a binary model using gradients may be almost as efficient as the model that uses the full gene profiles. We propose that a discrete model of positional information that includes gradients does not lose significant information over a model that uses full profiles. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 49-51).

Spontaneous chiral ordering in titanium diselenide

Mon, 01 Jan 2018 00:00:00 GMT

Spontaneous chiral ordering in titanium diselenide Mier Valdivia, Andrés M In this work, we studied the chiral charge density wave (CDW) phase in titanium diselenide (TiSe₂) with the circular photogalvanic effect (CPGE). Mechanically exfoliated bulk TiSe₂ flakes were obtained and implemented into nanoscale devices using standard fabrication techniques. Four samples' photocurrent response to a 120 meV laser was subsequently measured as a function of temperature and laser power. The onset of the CPGE at approximately 174 K confirms the emergence of chiral order below the regular CDW transition at 197 K. Furthermore, we were able to train the chirality of the system by cooling it while shining circularly polarized light. With this study, we have confirmed that TiSe₂ is a novel kind of material that spontaneously breaks inversion, all mirror, and roto-inversion symmetries and attains gyrotropic order, paving the way for future experimental work on similar condensed matter systems. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 69-72).

The absorption of nitrogen dioxide in concentrated nitric acid

Mon, 01 Jan 1940 00:00:00 GMT

The absorption of nitrogen dioxide in concentrated nitric acid Stern, William Rogers Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1940.; MIT copy bound with: The use of a liquid model in studying the characteristics of non-premix flames / Judson M. Rogers. 1940.; Includes bibliographical references (leaf 48).

Understanding the relationship between weather conditions and home run rates in the MLB

Mon, 01 Jan 2018 00:00:00 GMT

Understanding the relationship between weather conditions and home run rates in the MLB Ashoff, Tyler (Tyler L.) This observational study explores the relationship between home run rates and weather conditions, both on game day and over the preceding weeks. Data were collected from ESPN and Weather Underground for over 36,000 games between the 2003 and 2017 seasons. These consisted of game statistics and 59 weather variables. Random Forests was used to determine which set of these variables were important predictors of home run rates. Humidity was found to be the most important weather variable for predicting home run rates. The data suggest that a change of game day humidity from 100% to 0% can increase home run rates by 27% and ball travel by 15ft. For access to the data, please visit tylerashoff.com. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 24).

A preliminary analysis on the emotional impact of synchronous, collaborative CAD tools

Mon, 01 Jan 2018 00:00:00 GMT

A preliminary analysis on the emotional impact of synchronous, collaborative CAD tools Arnet, Cameron (Cameron Josef) This thesis seeks to explore the effectiveness or lack thereof of synchronous, collaborative CAD software, and compare the performance of individuals utilizing such software to one another. Two platforms were used, Solidworks and Onshape, in which the latter had both an independent and a synchronous, collaborative option available. 16 individuals who were already familiar with CAD tools participated in the study, with each utilizing one of the prescribed workflows for the entirety of the hour long trial. Video of the participant's faces and onscreen interaction with the software was recorded throughout the duration of a prescribed task, and the video was utilized in the analysis section of this study. An in depth empirical and statistical analysis is subsequently outlined, and is intended to be utilized as a stepping stone to a later study that will correlate the emotional analysis summarized here with another study dedicated to the user interaction with the software. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 29).

Analysis of a shuffling detection device for fall prevention

Mon, 01 Jan 2018 00:00:00 GMT

Analysis of a shuffling detection device for fall prevention Alexander, Alaisha (Alaisha Diahann) According to the World Health Organization, falls are the second leading cause of accidental or unintentional injury deaths worldwide. In order to address this issue from a fall prevention perspective, I began developing a footwear device to give feedback to the user on their walking. In this iteration, I've identified characteristics to distinguish between shuffling and walking strides for implementation in a threshold-based algorithm and the device created was effective in making this distinction with a 74.65% accuracy and 73.17% sensitivity. The errors identified are those common to threshold-based algorithms and can be corrected in future iterations with a more sensitive threshold and stride detection method. Moving forward, the device can be improved in order to be integrated into a feedback device for the intended user. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 16).

Identification and evaluation of techniques for quality control of low-cost xylem filters

Mon, 01 Jan 2018 00:00:00 GMT

Identification and evaluation of techniques for quality control of low-cost xylem filters Arkhurst, Bettina K 2.1 billion people worldwide, majority of whom are of the poorest income quintile, lack access to safe, readily available water in their homes. The need for affordable, decentralized methods of water filtration led to the development of a low-cost membrane filter produced from the xylem of coniferous trees. Due to xylem structure variation and the potential for improper filter processing during mass production, quality control protocols are a necessity. Manufacturers must ensure xylem filters are functional in terms of microbial rejection and adequate flow rates. Testing methods similar to those mentioned in this thesis can also be developed for other membrane filters. The suitability of two fluids, water and air, were evaluated for use in the quality control process. For testing using water, turmeric and blue dye were used to create a visual indication test to detect a filter's major failures. We found that this method has the potential to detect both leaks and improperly prepared filters, but it lacks affordable, quantitative analysis for determining rejection percentages. Air was found to be a viable option for xylem filter testing at pressures of 6 psi and above, though presence of the xylem lowered the concentration of particles detected at the outlet by one-fourth. The substances found to be most suitable for testing the filter were Baker's yeast, jeweler's rouge, turmeric, and buttermilk given their affordability, particle/microbe size, and availability. Further exploration is required to determine the optimal particle to use in water and air testing and the equipment necessary for the quality control process to be implemented. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 49-51).

Angled roller mecanum wheel design that exhibits speed reduction

Mon, 01 Jan 2018 00:00:00 GMT

Angled roller mecanum wheel design that exhibits speed reduction Abdalla, Ali Alsalih This thesis presents the testing of speed reduction exhibited by custom angle mecanum wheels. A simple trigonometric model is put forth for the speed reduction, along with the kinematic analysis and simulation of a 3-wheeled-vehicle. Then a 150 mecanum wheel is designed and built, along with a testing fixture allowing it to freely move in the direction the roller pushes towards. This fixture also allowed the collection of the encoder data from the motor and the linear distance the wheel travels. Based on that, the detected speed reduction ratio was 4.9:1, as opposed to the modeled ratio of 3.9:1. This discrepancy is likely cause by the absence of slippage in our model, the jiggle in the wheel's motion, the compliancy of the surface it rotates on, as well as the uncertainty from the linear distance measurement. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 35).

Non-invasive system identification of a tactical generator

Mon, 01 Jan 2018 00:00:00 GMT

Non-invasive system identification of a tactical generator Bell, John Harry, IV Microgrids, small power distribution networks, are gaining traction as an approach to increasing the fuel efficiency of tactical operations. In order to design controllers for microgrids, accurate models of the generators providing power are needed. In this thesis, non-invasive experimental methods for determining synchronous machine system parameters for a Tactical Quiet Generator (TQG), a generator commonly used by the US military, are explored. While the generator's rotor is at standstill, direct voltage excitation over a large range of excitation frequencies of a synchronous machine's stator is employed to determine electrical parameters for the synchronous machine. With the generator in running, the response of the frequency of generated AC power to a step in load is employed to determine the inertia of the generator's rotor. The stator excitation test is performed with the rotor positioned at a series of angles relative to the stator, so as to determine the location of the principal axes (d and q axes) of the rotor and impedances of the synchronous machine as seen in the d-q reference frame. Least-squares curve fitting is applied to the Bode plots of these impedances to fit the predictions of equivalent circuit models to the data, thus determining the model parameters represented by each equivalent circuit element. For the load step response test, the swing equation is used to calculate the system inertia from measured changes in frequency due to known steps in power. From execution of these techniques, it was determined that they are viable methods for estimating system parameters, though greater precision needs to be exercised in the stator excitation test in order to accurately estimate parameters. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 57-58).

Fabricating sand cast parts for a Herreshoff steam engine

Mon, 01 Jan 2018 00:00:00 GMT

Fabricating sand cast parts for a Herreshoff steam engine Bianchini, Elizabeth (Elizabeth G.) Through a Pappalardo Apprenticeship program, MIT undergraduates in mechanical engineering collaborated to construct an 1897 Herreshoff steam engine for intent for demonstration at an MIT Museum exhibit scheduled to open in fall 2018. With a brief overview of the functionality and inner workings of the engine provided, this thesis focuses on the fabrication process followed in making a sand cast part for this project. Two specific parts exemplify the variations in this fabrication process: the iron column and the bronze bearing crosshead. In both cases, the same CAD and CAM practices, pattern fabrication processes, and post-machining techniques were used. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 55).

Cost analysis and profitability of the cable train : a mobile platform for manufacturing underground cable systems

Mon, 01 Jan 2018 00:00:00 GMT

Cost analysis and profitability of the cable train : a mobile platform for manufacturing underground cable systems Bratten, Richard C As the profitability and technological viability of renewable energy projects continues to improve, the issue of connecting remote supply and demand becomes increasingly important. In certain instances where supply and demand locations are far apart, high voltage direct current (HVDC) power transmission lines become more efficient and cost effective than traditional alternating current lines. Installing overhead HVDC cables is sometimes the simplest, cheapest solution to this problem, but there is often difficulty in getting these projects approved due to public displeasure as well as higher security risks. The alternative solution, laying underground lines, can be four to fourteen times more costly than overhead lines. However, over long distances, there is a break-even distance where underground HVDC becomes more efficient than overhead because of factors such as lower power losses, less accessories are necessary, and a smaller right-of-way is required. Luke A. Gray, Professor Alexander H. Slocum, et al. have proposed a method of transporting raw materials along existing railroad lines and continuously manufacturing and laying HVDC cables in trenches made along the railroad's right-of-way.We hypothesize that it is possible to lay HVDC cable at a lower cost than traditional methods by using this newly proposed solution. This paper investigates the cost breakdowns of both the overhead and operating costs involved in a "Cable Train" HVDC cable manufacturing system and does a fiscal analysis of profitability and potential for scaling. The overhead costs of the "Cable Train" provide a relatively high barrier to entry at $61 million, and operating costs for the project in our chosen configuration are $2.8 million per mile. Compared to $21.1 million for other projects discussed in this paper in the same configuration, the Cable Train lays cable at a much lower cost. For expected project lengths of over 100 miles, overhead becomes relatively small, indicating high potential for the "Cable Train" to be used on different projects. Methods used to calculate the costs of overhead on the "Cable Train" rely on quotes (minimum of two) provided by anonymous vendors, while operating costs largely rely on industrial estimation methods requiring two or more statistics gathered by myself, Gray, or by data conglomerates. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 33-35).

Design of a rear powertrain and suspension system for an electric vehicle

Mon, 01 Jan 2018 00:00:00 GMT

Design of a rear powertrain and suspension system for an electric vehicle Fisher, Jacob Charles This is the summary of the design process of the drivetrain and suspension systems made for the purpose of converting a 1972 Opel GT to electric power. The goals of this study were to optimize the suspension for ride handling as well as integrate the suspension and power systems into a single modular unit that could then be tweaked for integration into other electric vehicle conversion projects. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 17).

Design of a control system for a mobile torrefaction reactor

Mon, 01 Jan 2018 00:00:00 GMT

Design of a control system for a mobile torrefaction reactor Garcia, Alejandro, S.B. Massachusetts Institute of Technology In MIT's Tata Center, work is being done to develop a mobile torrefaction reactor that can be used to aid those in developing countries in need of alternative sources of energy. A vital component of the reactor is developing an appropriate control system for the necessary components. The previous method of control has proven time intensive, inaccurate, and overall inefficient. A new control method is needed to allow for effortless control of the torrefaction reactor both in the lab and on the field. The new controller would have to be compact, control multiple components simultaneously and be uncomplicated to use. The proposed solution is to utilize a microcontroller board to develop a singular interface that would provide ease of use and the ability to accurately control all of the components involved in the reactor. It would utilize a simple numeric keypad to receive inputs that would be used to control the components and a small lcd display to monitor the system. Despite not being able to build the final control system, the framework for it has been developed here and suggestions on moving forward are outlined. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 49-50).

Design of water carts as educational and cultural objects in Syrian refugee camp

Mon, 01 Jan 2018 00:00:00 GMT

Design of water carts as educational and cultural objects in Syrian refugee camp Kawecki, Anthony Ray The Future Heritage Lab at the Massachusetts Institute of Technology has been working with residents of the Azraq refugee camp to develop projects that address the issues of everyday life within the camp. One prevalent problem is the lack of access to water. It is often the duty of children to hike through the desert sands in order to fill their jugs with water and lug them back home for their families. In order to address this issue, this thesis explores means of constructing carts for carrying water. The cart will serve both as a tool for transporting water, and as an object of play for those who use it. Through its design and construction, people in the camp will learn valuable lessons in engineering and gain hands on experience using the tools to build it. Materiality is an important factor in the development of the cart. One model will be constructed at MIT as a proof of concept from PVC pipe and bicycle components, then the final versions will be comprised entirely of scrap bike frames and other components from within the camp. On top of its water carrying capability, the cart will also serve as a cultural object. One of the greatest struggles within these refugee crises is how heritage and culture can be preserved and celebrated through displacement. With that in mind, this portion of the cart will include history lessons and references to pre-Islamic mythology, in order to inspire a cultural symbolism to be integrated into the design of the carts. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references.

The effects of inelastic self-interacting dark matter on galactic halo properties v/

Mon, 01 Jan 2018 00:00:00 GMT

The effects of inelastic self-interacting dark matter on galactic halo properties v/ Dibert, Karia Radh Self-interacting dark matter, which serves as an alternative to collisionless cold dark matter, may be useful for solving the small-scale galaxy formation problems present in the Lambda-Cold Dark Matter model. So far, most self-interacting dark matter simulations have considered only elastic collisions between particles. Using the results of a numerical implementation in the AREPO code, the effects of two-state inelastic dark matter on the density profiles, velocity dispersions, pseudo-phase-space density profiles, orbital anisotropy parameter profiles, and principal axis ratios of galactic halos are examined. We find that inelastic self-interacting dark matter halos differ from both cold dark matter halos and elastic self-interacting dark matter halos in density profiles, in velocity dispersion profiles, in pseudo-phase-space density profiles, and in orbital anisotropy parameter profiles, while the shapes of the halos generated by elastic and inelastic self-interacting dark matter models are relatively similar. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 37-40).

Signatures of hydrodynamic transport in an electron system

Mon, 01 Jan 2018 00:00:00 GMT

Signatures of hydrodynamic transport in an electron system Guo, Haoyu, S.B. Massachusetts Institute of Technology Electrons in strongly-correlated systems move in a neatly coordinated manner, in many ways resembling the movement of viscous fluids and leading to surprising collective behaviors. Here we explore how the hydrodynamic behavior manifests itself in the electron transport through nanoscale constrictions. Free electron flows through constrictions in metals are often regarded as an ultimate high-conduction charge transfer mechanism. However, as shown in this thesis, interactions can facilitate transport and give rise to super-ballistic conduction, allowing conductance to exceed the ballistic limit value. In other words, interactions and viscous effects, rather than presenting a hindrance for conduction, help increase carrier mobility and suppress dissipation. This interesting behavior represents a clear signature of the electron hydrodynamic regime, and provides a way to determine electron viscosity. These results show that interactions and viscous effects can facilitate high-mobility transport, granting a new route for designing low-power nanoscale devices. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 63-64).

Quantum blackjack : quantum strategies and advantages in games with limited classical communication

Mon, 01 Jan 2018 00:00:00 GMT

Quantum blackjack : quantum strategies and advantages in games with limited classical communication Lin, Joseph Xiao In this thesis, we examine the advantages that quantum strategies afford in communication-limited games. Inspired by the card game blackjack, we particularly focus on cooperative, two-party sequential games in which a single classical bit of communication is allowed from the first-mover to the late-mover. Within this setting, optimal usage of quantum entanglement is explored, and conditions of quantum advantage over classical strategies are examined. Furthermore, theoretical, computational, and experimental techniques are presented that can be useful in the analysis and implementation of quantum strategies in these types of games. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 59-60).

Photon isolation and jet substructure

Mon, 01 Jan 2018 00:00:00 GMT

Photon isolation and jet substructure Hall, Zachary (Zachary H.) We introduce soft drop isolation, a new photon isolation criterion inspired by jet substructure techniques. Soft drop isolation is collinear-safe and is equivalent to Frixione isolation at leading order in the small R limit. However, soft drop isolation has the interesting feature of being democratic, meaning that photons can be treated equivalently to hadrons for initial jet clustering. Taking advantage of this democratic property, we define an isolated photon subjet: a photon that is not isolated from its parent jet but is isolated within its parent subjet after soft drop declustering. The kinematics of this isolated photon subjet can be used to expose the QED splitting function, in which a quark radiates a photon, and we verify this behavior using both a parton shower generator and a perturbative calculation in the collinear limit. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 41-45).

Controlling light emission with shaped electron wavefunctions

Mon, 01 Jan 2018 00:00:00 GMT

Controlling light emission with shaped electron wavefunctions Murdia, Chitraang The extent to which can one change the nature of spontaneous emission from a free electron by shaping the its wavefunction has been a long-standing question. In this work, we use both a semi-classical formalism and a QED formalism to show that Bremsstrahlung radiation can be tailored by altering the electron superposition states. Using the semi-classical formalism, we show that wavefunction shaping can greatly enhance the collimation of radiation from electron beams passing through spatially periodic electromagnetic fields, such as those in undulators. Moreover, the radiation from rapidly decelerated shaped electrons can be made directional and monochromatic. Using the QED formalism, we show that the radiation can be markedly different from an incoherent sum of the radiations of the two states because of interference between the scattering amplitudes from the two components of the superposition. The ability to control free electron spontaneous emission via interference may eventually result in a new degree of control over radiation over the entire electromagnetic spectrum in addition to the ability to deterministically introduce quantum behavior into normally classical light emission processes. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 65-67).

The search for orbital decay in hot Jupiters

Mon, 01 Jan 2018 00:00:00 GMT

The search for orbital decay in hot Jupiters Patra, Kishore Chandra We summarize our results, so far, in the search for orbital decay in exoplanets. Orbital decay is the gradual shrinkage of the planetary orbit due to tidal dissipation. We ranked currently known exoplanetary systems according to the theoretical orbital decay rate and trimmed the list down to 12 best targets. We collected new transit light curves for the targets visible in the northern hemisphere using the 1.2 m telescope at the Fred L. Whipple Observatory, Arizona. For the southern targets, we are currently collaborating with the Las Cumbres Observatory Telescope Network to obtain new transits. We analyzed the timing residuals for each target, seeking evidence for any change in the orbital period. Currently, the best candidate for orbital decay is WASP-12 b with an observed period derivative ... . However, we find that a few other possible models, including apsidal precession, nodal precession and color-dependent transit times, cannot be ruled out completely. Continous monitoring of WASP-12 b is necessary in the future to resolve the current conundrum. The search for orbital decay is still in its infancy for most other targets. However, we aim to produce a few transit times for each target to serve as an "anchor" for when TESS relays back more high quality light curves. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 87-93).

Diffusional instabilities on curved manifolds

Mon, 01 Jan 2018 00:00:00 GMT

Diffusional instabilities on curved manifolds Shackleton, Henry (Henry J.) Diffusionally-driven instabilities provide a versatile mechanism for pattern formation, and have found applications in modeling a variety of biological and chemical systems. Although pattern formation has been observed in systems with a variety of geometries, the theoretical study of diffusional instabilities has primarily been restricted to systems of uniform curvature, such as flat planes, spheres, and cylinders. In this thesis, I study a method of analyzing pattern formation on more generally deformed surfaces, with a focus on perturbatively calculating effects due to small deformations from geometries of uniform curvature. Analytical predictions, ranging from pattern modifications to pinning of pattern development, are obtained on deformed drums, cylinders, and spheres. These predicted effects are compared to numerical studies, and additional cases where our analytical methods break down are studied numerically. Finally, the interplay between advection and non-uniform curvature is studied numerically. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 61-64).

A method for detecting nonequilibrium dynamics in active matter

Mon, 01 Jan 2018 00:00:00 GMT

A method for detecting nonequilibrium dynamics in active matter Watson, Garrett (Garrett A.) Active force generation is an important class of out-of-equilibrium activity in cells. These forces play a crucial role in vital processes such as tissue folding, cell division and intracellular transport. It is important to determine the extent of such nonequilibrium activity during cellular processes to understand cell function. Here we present a framework for measuring nonequilibrium activity in biological active matter using time reversal asymmetry based on the Kullbeck-Leibler Divergence (KLD), also known as relative entropy. We estimate the KLD from a stationary time series using a k-nearest neighbors estimator, comparing the time-forwards process to the time-reversed process Using time series data of probe particles embedded in the actin cortex, we establish a lower bound for the entropy production of cortical activity. Our results demonstrate a reliable way to measure the breaking of detailed balance in mesoscopic systems. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 55-56).

Modeling beta decay spectra to analyze the sensitivity of a neutrino mass experiment

Mon, 01 Jan 2018 00:00:00 GMT

Modeling beta decay spectra to analyze the sensitivity of a neutrino mass experiment Weiss, Talia E The Project 8 experiment aims to measure the electron neutrino mass by obtaining and analyzing [beta] spectra from tritium decay. Using an inferential model of the experiment's anticipated data, I evaluate its projected sensitivity to certain parameters of interest. I focus on the precision and accuracy with which Project 8 can expect to resolve the [beta]-decay spectrum's endpoint in an upcoming stage of the experiment. I also present an initial prediction of Project 8's eventual expected sensitivity to the electron neutrino mass. This analysis involved generating and analyzing [beta]-decay spectral data using a model implemented in Stan, a platform for Bayesian statistical inference. The sensitivity analysis was designed to account for the anticipated distribution of results (mass and endpoint measurements) produced by the potential variation in a number of physical and experimental parameters. In addition, the method used here allows for a calibration of the consequences of inferences and decisions made in reaching those results. I find that, using one year of Project 8 Phase II data, the T2 endpoint can be resolved within a 13.7 eV window (90% C.I.) with 62% coverage (or accuracy), corresponding to a 4.1 eV posterior standard deviation. Preliminarily, using one year of Phase IV data, the electron neutrino mass can be resolved within a 0.051 eV window (90% C.I.) with 56% coverage. I also outline a way that model-based sensitivity procedures and calibration of inference can be extended to the neutrino mass hierarchy problem. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 46-47).

Statistical analyses of gravitational microlensing probability densities

Mon, 01 Jan 2018 00:00:00 GMT

Statistical analyses of gravitational microlensing probability densities Yahalomi, Daniel Alexander Gravitational microlensing is a powerful modelling tool, that is essential in accurately understanding the lensing behavior of astronomically strong lensed objects. Using Joachim Wambsganss micro-magnification maps, we discuss the creation of a Monte-Carlo tool that can determine the likelihood for microlensing to account for flux ratio anomalies between macro-models and observations. We apply this tool to the study of iPTF16geu, a recently discovered type IA lensed supernova, and determine that it is unlikely for microlensing alone to account for flux ratio anomalies. We apply the tool, and an extension of the tool that allows us to predict the source's intrinsic magnitude, to Huchra's Lens. We study the light curves of Huchra's lens over time, and predict that image B is stuck in an uninteresting place in its micro-magnification map, causing its microlensing to consistently corrupt the source light curve over the past twenty years. Using Charles Keeton's lens model, a macro-modelling tool, we investigate the quadruply lensed system, DES J0408-5354. We present a new macro-model for the system, which predicts that image C, a perturbed saddle point, is outside the second perturbing galaxy relative to the primary lensing galaxy. This represents a new macro-model for the system, supported by recent unpublished Hubble observations. Finally, we present a method for investigating the quasar continuum emitting region size, and a way to test the point-like assumption at varied wavelengths. We discuss the framework and describe the process for how future work can provide essential constraints on the quasar continuum emitting region. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 67-69).

Micro-images of macro-lensed objects

Mon, 01 Jan 2018 00:00:00 GMT

Micro-images of macro-lensed objects Weisenbach, Luke The study of gravitational micro-lensing at high optical depth has only rarely involved the close examination of the individual actual micro-images that arise as a result of the phenomenon. We discuss methods that refine on previous work done in the search for micro-images, which have been largely ignored in favor of other methods to study micro-lensing. With the help of magnification maps generated by Herr Prof. Dr. Joachim Wambsganss, we ran simulations that track positions and magnifications of micro-minima as functions of source position. We discuss the breakdown of a commonly used approximation for magnifications near fold caustics. Our results show that the approximation is noticeably broken at a caustic strength-scaled distance of 0.1. The relevance of this breakdown to work done by other authors is briefly examined. We then then discuss a few new results for the statistics of micro-images, deriving a formula for the mean micro-minimum magnification. We present a method for exactly calculating the caustic networks of micro-lensed systems, and calculate probability distributions for the caustic strength for two sets of parameters of interest. We present the creation of videos of the micro-lensing affect for pedagogical purposes. Finally, we briefly examine micro-lensing near macro-caustics and study the motion of micro-images as a point source crosses a macro-caustic. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 79-80).

A study of the use of scientific and technical data in judicial decision-making

Mon, 01 Jan 1979 00:00:00 GMT

A study of the use of scientific and technical data in judicial decision-making Neblett, Adonis A. (Adonis Alfonso) Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1979.; MIT copy bound with: Development of a recycle reactor for methanation rate studies / by William S. Kleinman [1979] jlh; Includes bibliographical references (leaves ).

An investigation of the aerodynamic characteristics of a combined swept back-swept forward wing configuration

Thu, 01 Jan 1953 00:00:00 GMT

An investigation of the aerodynamic characteristics of a combined swept back-swept forward wing configuration Mazzola, Luciano L; Romer, Eugene Mark Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Aeronautical Engineering, 1953.; MIT copy bound with: Stiffener design for light planes / David Lissner. 1953.; Bibliography: leaf 17.

Axially force limited grinding spindle for robotic grinding

Mon, 01 Jan 2018 00:00:00 GMT

Axially force limited grinding spindle for robotic grinding Brown, Austin (Austin R.) Grinding and Polishing of small parts is often easily performed by human hands, yet is challenging to automate. The grinding and polishing process is best done using a force-control scheme, which human hands perform naturally. Heavy robotic arms, which favor a position-control scheme, are difficult to control precisely, and trajectory errors can cause excessive grinding force which leads to burning of the part or destruction of the grinding wheel. Prior art of direct force control on a large robot arm requires the end-effector to have a 6-axis dynamometer, which is unwieldy, costly, and greatly limits the speed/precision of the process. We will discuss a new type of grinding spindle which is axially compliant, allowing the position-control robot arm to be used in a force-control nature. The spindle has a disjoint force-displacement curve, effectively operating in two modes: position-control mode at first, until a critical force is exceeded, when the spindle transitions into force-mode, keeping constant grinding force on the part though a certain range of travel. This limits the amount of force which can be imparted during grinding to a safe amount. The spindle is very simple and mechanically robust. We have built this hybrid position-force control spindle and tested it. The spindle was shown to perform correctly and successfully completed the test grind. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 35).

Effects of training methods on classification on surface electromyographic signals for myoelectric control

Mon, 01 Jan 2018 00:00:00 GMT

Effects of training methods on classification on surface electromyographic signals for myoelectric control Day-Williams, Hugh C Myoelectric devices, devices which use the electric signals from human muscles as a control scheme, have shown promise in their potential to aid in human movement augmentation and assistance for those that have suffered injury. Previous studies involving myoelectric devices and the classification of surface electromyographic (sEMG) signals, electrical impulses obtained from muscles from sensors on the skin, have sought to use various types of machine learning models for sEMG pattern recognition. This technique shows promise in being able to accurately classify human sEMG signals and map them to certain movements, which can then be used as a method of myoelectric control. In this study we explored how two methods of training a K-Nearest Neighbor (KNN) classifier, used to control a MyoPro arm orthosis, affect two subjects' performance on various experimental tasks and their measured sEMG activation throughout the tasks. It was found that for subject 1, the assisted training method, where another individual helps move the orthosis while training the KNN, resulted in a lower variance in the measured mean sEMG values, and reduced the cross validation accuracy of the controller, but did not reduce subjects' performance of the experimental trials, as compared to the KNN controller trained without assistance. For subject 2, the assisted controller reduced the performance on three out of the four tests performed compared to the unassisted controller. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 25).

Tactile sensor design optimization for footwear applications from piezoresistive elastomer to Hall-effect integrated sensing methods

Mon, 01 Jan 2018 00:00:00 GMT

Tactile sensor design optimization for footwear applications from piezoresistive elastomer to Hall-effect integrated sensing methods Chen, Ann Annie Our ability to move across various terrains depends heavily on the mechanical interactions between our feet and the external environment. Understanding how to best replicate mechanoreceptors in feet can lead to major improvements in plantar sensing for athletic performance analysis and medical devices. However, current plantar sensing technologies are unable to meet the associated demands for accuracy, sensitivity, and durability. In addition, current sensors are also unable to withstand the large impact forces and inertial noise associated with human locomotion. To address this issue, this thesis investigates alternative designs for a tactile force sensors that are largely inspired by mechanoreceptors found in human skin. Two different sensing methodologies will be analyzed: piezoresistive elastomer and Hall-effect integration. The piezoresistive elastomer method will involve testing mixtures of urethane or silicone rubbers with various conductive substances such as carbon black. Compressing the sensors at various forces will correspond to lower resistance measurements as more electrical connections are made by the conductive particulates. Though these designs have high sensitivity to changes in force, the resulting data is inconsistent and slow to stabilize due to material creep. The Hall-effect integrated method will involve a magnet and four Hall-effect sensors molded in an elastomer matrix. Compressing the sensors will register different readings in each of the four embedded Hall-effect sensors which will correspond to a certain shear and deflection measurement. This sensor design shows promise as a cost-effective plantar sensor, but additional analysis is needed. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 51-54).

The development of online media to support design prototyping with a laser cutter

Mon, 01 Jan 2018 00:00:00 GMT

The development of online media to support design prototyping with a laser cutter Diaz, Stephanie, S.B. Massachusetts Institute of Technology Online education has been growing and there has also been work done to support residential design education with online media. This thesis focuses on developing online media providing instruction on how to use the laser cutter, a tool that can be used in early-stage prototyping as part of the design process. User research was conducted to understand what information would be helpful for design students while using the laser cutter. The development of the site, targeting MIT Mechanical Engineering design students who are beginner level laser cutter users, is discussed. The resource explains the basics of using the laser cutter and provides additional content and resources that may be useful to design students. The webpage is meant to serve as a reminder of how to operate the tool following training by an authorized laser cutter user. The resource was tested with 7 design students with zero to limited experience using a laser cutter. The tests were successful and showed that the webpage was helpful in providing students with the information needed to create a simple laser cut part without overwhelming them with too many details. A list of revisions and additional media that should be added was developed. Future work should include the development of a webpage targeting intermediate to advanced laser cutter users. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 41).

Making Haiti "The Pearl of the Antilles" again : what can be done?

Mon, 01 Jan 2018 00:00:00 GMT

Making Haiti "The Pearl of the Antilles" again : what can be done? Delmy, Cédric From being the "Pearl of the Antilles", Haiti has regressed to being the poorest country in the Western hemisphere. Several factors contributed to this decline, including a long history of exploitation, corruption, political instability, and devastating natural disasters. Today, only 25% of the population has access to electricity [1], and 71% has access to water with low level of sanitation [2]. To remediate that, this thesis proposes to Integrate Pumped Hydro systems with Reverse Osmosis plants (IPHROS) to reduce the capital and operating cost of the systems if they were to be built separately. The overall goal is to provide clean energy and freshwater to the Haitian population. An analysis of Haiti's topography showed that the southeast region of the country would be a prime candidate for IPHROS which requires an elevation of at least 500m as close as possible to the sea. We found that if used to its full potential, the region can provide freshwater and energy to more than 30% of the population. It was also found that such a project could cost around USD 6.5 billion which would need to be supplied mostly through investment. Haiti's political atmosphere as well as our society's value system, makes it challenging to attract investors. Fortunately, a micro-utility company, called Sigora Haiti, might provide an opportunity for a partnership that would help implement IPHROS and get Haiti back on the right development path. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 17-18).

Mechanical design of a jumping and self-balancing monopedal robot

Mon, 01 Jan 2018 00:00:00 GMT

Mechanical design of a jumping and self-balancing monopedal robot Brown, Evan (Evan C.) This project involved the design and fabrication of a self-balancing monopedal robot which is intended to be used as a platform for physically validating simulated risk network based control analysis. A precomputed risk network allows a robot to evaluate the risk that an action will lead to an imminent fall or lead to a state from which the robot will eventually fall after several jumps.' The physical implementation of the simulated robot will allow the theoretical boundaries of safety to be validated. If validated, risk matrix analysis will allow a system to be modeled such that the controller can modify control inputs which would lead falls. The results of physical testing will be used to refine the simulated model. The robot was designed to be as simple as possible while still being capable of operating in three dimensions to study hybrid dynamics and underactuated locomotion. A mechanism with a direct kinematic relation to the output along with a static contact area was designed to allow the ground force profiles to be accurately controlled. In order to utilize the risk network, the force applied by the foot as well as the robot's take-off angle and rate of angular rotation at take-off are key parameters which must be measured and controlled. The robot was be optimized to precisely control these parameters rather than to achieve the longest or highest jump possible as is the objective of other studies. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 59-60).

Luck and skill in professional League of Legends (E-sports)

Mon, 01 Jan 2018 00:00:00 GMT

Luck and skill in professional League of Legends (E-sports) Douglas, Cameron (Cameron David) As professional gaming (e-sports) develops a greater global infrastructure, it will be critical to create league systems in which skill and luck balance to create competitive, exciting, and fair environments. This study uses the most developed e-sport leagues, found in the game League of Legends (LoL), to examine early efforts at crafting such environments. The use of "winning persistence" and Bayesian statistical analyses reveal that best-of-one matches in LoL demonstrate an overall luck-skill ratio similar to professional baseball (MLB) and football (NFL). Best-of-three matches exhibit an understandably higher ratio of skill, similar to professional basketball (NBA). With both match lengths exhibiting viable but significantly different luck-skill ratios, LoL creator, Riot Games has the tools to control how much luck and skill exist in their matches and leagues, setting an important precedent for future leagues and organizations. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 35-36).

Design of a hermetically sealing inlet for in-situ planetary exploration

Mon, 01 Jan 2018 00:00:00 GMT

Design of a hermetically sealing inlet for in-situ planetary exploration Fessenden, Jane Mae A miniature low-powered life detection device for in-situ isolation and sequencing of nucleic acids is to be used to test the hypothesis of a plausible shared ancestry due to meteoric exchange between Earth and Mars. The soil sample collection inlet is a critical part of the device. The following paper presents a design review of previous inlet mechanisms and an inlet design proposal for in-situ planetary exploration. The key attributes of the design are the sealing interfaces and an inverted dovetail cross sectional geometry for a linear carriage. The inlet emphasizes a design for manufacturability, weight savings, durability, and many cycles. Based on the established fundamental requirements, the design is evaluated on the thermal analysis at the extreme theoretical temperatures and the force, power, and energy required to actuate and seal the inlet, using Finite Element Analysis and numerical computation. The design successfully meets the majority of the fundamental requirements. The modularity and low required actuation force of the design are applicable to many current and future space instruments. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 101-106).

Analyzing how optimization features impact people's use of design tools

Mon, 01 Jan 2018 00:00:00 GMT

Analyzing how optimization features impact people's use of design tools Gaylord, Elizabeth (Elizabeth H. W.) Design is the first step in creating a product but can be the most challenging. Much design software has been created to meet these needs, but these tools consider only a small part of the design process. This limitation stunts creativity and provides challenges to designers when trying to solve complex problems. Better tools take into account the needs of designers throughout the process of creating, analyzing, and optimizing designs. To provide the best integrated solutions, it is necessary to determine what features of analysis and optimization most help designers explore the solution space and ultimately create better physical designs. Tacit was developed as research tool to create simple designs with analysis and optimization built-in to the software. The most optimized version of Tacit was used as the control in a new study, which utilized two new versions excluding certain optimization features. A comparison between these versions was done to examine how optimization features impacted overall result, solution space exploration, and user experience. The usefulness of these optimization features is highly dependent on the type of problem being solved, and these features do not guarantee the best solution or sufficient exploration of the design space. Results from this experiment allow researchers to identify what is most useful to designers and how better to design tools to help them. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 21-22).

Characterizing reaction bandwidths in a position-controlled robotic arm

Mon, 01 Jan 2018 00:00:00 GMT

Characterizing reaction bandwidths in a position-controlled robotic arm Gano, Selam Position-controlled robotic manipulators remain an industry standard but are ill-suited for guarded move approaches to advanced manipulation. Adding additional feedback with the expectation that a position-controlled system can account for it cannot guarantee successful implementation. To explore and define the limitations of position-controlled arms, I attempt to characterize different motion and force bandwidths of a large, 6-DOF robotic arm. Peak force and motion overshoot measurements were taken at varying speeds of the robot. These experiments showed that at speeds as low as 10 mm/s, the robot still exerted over 40 Newtons of force, enough to crush objects typically used for manipulation tasks. Overcoming these issues in using position-controlled arms are difficult to account for with software approaches, but different mechanical solutions can be envisioned to combat this problem in robotic manipulation. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 11).

Determining the effects of alloy composition, forging technique, and flux on the strength of forge welds

Mon, 01 Jan 2018 00:00:00 GMT

Determining the effects of alloy composition, forging technique, and flux on the strength of forge welds Gonzalez, Beatriz Andrea Welding is an essential manufacturing process in industries that require the joining of metal components such as the automotive and aerospace industries. While specialized techniques have developed for many of these industries, the process of welding remains fundamentality the same, and the effectiveness of these processes to securely join metal is always characterized by the material properties of the metal after welding. The tensile test performance of forge welds when made with different iron alloys, forge welding techniques, and fluxes was measured. The alloys used were 1018 steel, A36 steel and wrought iron. The forge welding techniques were the hydraulic press, the power hammer, and hand hammer. The fluxes were borax, fine silica sand, anti-borax, and no flux. Control tensile samples (un-welded) of each alloy, as received, were tested along with annealed samples. All testing was performed with an Instron 5984 Universal Testing Machine with 150kN capacity. The results of the welded alloy tests showed that welded 1018 and A36 steel both had considerably lower strength than their control annealed counterparts, whereas welded wrought iron remained just as strong. The results of the forge welding techniques test showed consistent welded A36 steel strengths across techniques used which may suggest that the effectiveness of particular techniques may be more dependent on experience and practice. The flux results show that silica sand and anti-borax work just as well as, if not better than, borax. Using no flux resulted in failed welding, revealing that achieving successful welds without flux requires more welding experience or a different method than the one performed by the welder of the samples for the present experiment. The results of the control alloys showed that 1018 and A36 steel both had considerably lower strength than their annealed counterparts, whereas wrought iron remained just as strong. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 41).

The optimization of a Formula SAE vehicle's suspension kinematics

Mon, 01 Jan 2018 00:00:00 GMT

The optimization of a Formula SAE vehicle's suspension kinematics Harvey, William Thomas, S.B. Massachusetts Institute of Technology The suspension geometry is the foundation of a performance vehicle's design because it dictates the overall packaging constraints and the connection between the chassis and the tires. This thesis details the design process used to produce the suspension geometry for MIT Motorsports' 2018 Formula SAE car and the justification for each design decision made. A thorough iteration process was used to prevent compromises that could significantly detract from specific component performance in order to meet suspension kinematic requirements. Using this process, the kinematic performance of the suspension was maximized by minimizing the roll center's movement and designing the tire camber change characteristics to achieve 0° of outer-wheel camber while at the car's maximum lateral acceleration. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 33).

Reverse-engineering a naturally-aspirated Lunenburg Foundry carburetor

Mon, 01 Jan 2018 00:00:00 GMT

Reverse-engineering a naturally-aspirated Lunenburg Foundry carburetor Hinton, Zoe Lynne The Lunenburg Foundry, based out of Nova Scotia, is a well-known manufacturer for early 20th century marine engines made famous by its Atlantic Marine Engine. This engine revolutionized the fishing industry along the Atlantic coast of Canada by creating a sort of "iron sail" for fisherman and sailors. The goal of this thesis is to reverse-engineer a naturally-aspirated Lunenburg Foundry carburetor from the Atlantic engine. The actual carburetor at MIT is one of few in existence, and has no accompanying patterns or drawings. The carburetor was disassembled and each part carefully measured by hand. A CAD assembly was developed of the entire carburetor to serve as an engineering database for future manufacturing and study. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 33).

Design and manufacturing of a microcalorimeter for measuring heat flows in electrochemical reactions to milli-Kelvin precision

Mon, 01 Jan 2018 00:00:00 GMT

Design and manufacturing of a microcalorimeter for measuring heat flows in electrochemical reactions to milli-Kelvin precision Kestin, Rebecca (Rebecca Sarah Elmer) Due to their high energy density, lithium-air batteries have tremendous potential for application to batteries for electric vehicles. While significant efforts have been made in understanding the material origins of electrochemical performance under discharging and charging conditions, there is still very limited understanding of the thermodynamics and thermal science, including heat transfer, of such reactions. Several methods and procedures that have been previously used to deduce entropy profiles in batteries are examined. One such microcalorimetric device allows for measurements of heat flows in electrochemical reactions to milli-Kelvin precision. This device has not previously been applied to gas-to-solid reactions. Next, an explanation of the design and manufacture of a device adapted to measure heat flows in solid-togas electrochemical reactions is explained. The high sensitivity of the measurements resulted in high noise levels. This paper also explains the main methods used to address and reduce this level of noise. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 27-28).

Realizing a design for a cloud chamber cooled by thermoelectric modules

Mon, 01 Jan 2018 00:00:00 GMT

Realizing a design for a cloud chamber cooled by thermoelectric modules Larson, Michael (Michael K.), S.B. Massachusetts Institute of Technology A cloud chamber consists of a super-saturated vapor inside a sealed chamber which forms visible trails of mist when radiation particles are emitted from a nearby source. Such behavior can be used to supplement the teaching of entry-level physics students, as the cloud chamber provides a visual demonstration for phenomena which otherwise might remain somewhat abstract, such as Lorentz Force Law. However, most cloud chambers require the use of material such as dry ice to induce surface temperatures below -26° C. Cooling a surface below this threshold enables the formation of super-saturated vapors of fluids such as isopropyl alcohol, which is used in this experiment. In order to address the problems with space, storage, and flexibility that typically exist with cloud chambers, this thesis explores the use of thermoelectric coolers (TECs) instead of dry ice to create the temperature difference needed to visualize radiation particles. The TECs, which are cooled by a Liqmax II 120S liquid CPU cooler, interface with a copper plate on which isopropyl alcohol forms a super-saturated vapor. A 3D printed plate houses the TECs and copper plate, and supports an acrylic covering which seals the chamber. Using a multi-stage TEC module, the copper plate reaches a temperature of -40° C within two minutes of being powered. The visibility of radiation in the super-saturated region was observed using three materials: Polonium-210, Lead-2 10, and Strontium-90. The cloud chamber can be improved and further work is discussed. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references.

Evaluating the feasibility of using screw conveyors as a means to continuously grow black soldier fly larvae

Mon, 01 Jan 2018 00:00:00 GMT

Evaluating the feasibility of using screw conveyors as a means to continuously grow black soldier fly larvae Ingram, Ty (Ty L.) This research attempted to assess the feasibility of using screw conveyors as a means of continuously rearing black soldier fly larvae. Farming of the black soldier fly (BSF) has gained popularity in recent years as means to supply protein for animal feed and recycle food waste. However current methods for BSF farming are labor intensive and costly. This is due partly from the batch system in which BSFs are grown. It is also a factor of space inefficiency, as BSF larvae can only live in the first 7-10 cm of the substrate they are grown in due to oxygen depletion. Screw conveyors in theory could solve both these problems by allowing for continuous production and mixing which could aerate the substrate preventing oxygen depletion. In order to test the feasibility of using screw conveyors an analysis was done to predicted energy cost. Based on the calculations done in this work energy cost would be trivial, on the order of 0.01 US dollars or less per pound of dry weight BSF larvae. Physical experiments were also done on the effectiveness of mixing in aerating the substrate and allowing BSF larvae to live deeper. This involved filling a tube with substrate and BSF larvae to various depth between 15 and 45 cm and measuring oxygen levels at the bottom depth. The tube was also flipped to simulate mixing. While there is a high level of uncertainty, the results in general indicate oxygen was depleted in the substrate on the order of 5-10 minutes for depths bellow 15 cm. This does not support the feasibility of using screw conveyors for BSF farming as the conveyor would have to be running almost constantly to prevent the development of anaerobic conditions. However many factors in this research where high conservative and the development of anaerobic zones in BSF substrate and the effects of mixing warrant further research. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 38).

Why engineering? : descriptive study mapping the motivations of aspiring engineers

Mon, 01 Jan 2018 00:00:00 GMT

Why engineering? : descriptive study mapping the motivations of aspiring engineers Lloyd, Isabel Marie As the importance of technology and innovation grows with the progression of society, so does the importance of engineers. Because of this, the engineering disciplines come with promise of good salaries and job security, but not all students choose engineering as a career path for the promise of jobs. In order to further understand their motivations, ten engineering students from the Massachusetts Institute of Technology were interviewed and eighteen others completed an online survey pertaining to their personal motivations for choosing engineering as a career path. The interview and survey questions gathered demographic information from each of the participants, statements regarding why they chose to attend MIT and pursue engineering as a career path, self reported data on their high school, university, and intended professional extra curricular activities, and lastly a list of their important personal values. Combined, the results of analysis showed that the motivations of aspiring engineers can generally be grouped into three broad categories - intrinsic motivation, external influence, and extrinsic motivation. The intrinsic motivation for choosing engineering comes from a place of interest in the subject matter, and the problem solving mindset necessary in the field. External influence refers to the outside factors to the decision making process such as role models or past experiences. The extrinsic motivation comes from a place of potential for impact creation, and the promise of creating long lasting and meaningful change. Though many students cite two or more of the broad motivational categories as important to their engineering aspirations, when asked to state the top contributing factor in their decision for choosing engineering all study participants responded within one of these three categories. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 70).

Solid particles flow through labyrinth channels in drip emitters

Mon, 01 Jan 2018 00:00:00 GMT

Solid particles flow through labyrinth channels in drip emitters Luu, Trang (Trang N.) Clogging of drip irrigation emitters can reduce the effectiveness of drip irrigation systems. The most common way of studying clogging in a laboratory setting is to recreate the actual timing conditions of on-site drip irrigation systems. However, this requires a clogging period on the order of hours to days and an intermission period on the order of days to weeks. This thesis explores the recreation of actual drip irrigation clogging effects in lab in a shorter amount of time, using water highly concentrated with grit particles. Three different non-pressure compensating emitters with rated flow rate of 0.8 LPH, 1.6 LPH, and 2.0 LPH from Jain Irrigation System were studied. Eight different concentrations of grit were pumped through the system. A clogging period of 30 minutes and an intermission period of 30 minutes were used in the tests. The grit used was aluminum oxide sized at 180 microns. The flow rate and discharged from each emitter were measured and calculated. The data showed a significant amount of clogging with high grit concentrations. This thesis will serve as the first part to achieving a short term clogging procedure for drip irrigation that will significantly allow more emitters designs to be tested and improved upon in shorter amount of time. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 24-25).

Improving surface quality of SLA 3D printed parts via controlled dip-coating

Mon, 01 Jan 2018 00:00:00 GMT

Improving surface quality of SLA 3D printed parts via controlled dip-coating Lu, Shirley Suet-Ning 3D printing is useful for rapid prototyping, and is quickly becoming an option to aid in mass manufacturing, whether to make low-volume molds for injection molding and thermoforming or to make unique fixtures. 3D printing via stereo lithographic apparatus (SLA) builds parts by curing photopolymer resins layer by layer. SLA 3D printing is often chosen for its relatively high quality surface finish. However, the average surface roughness of SLA 3D printed parts is in the range of 0.4 to 2 [mu], which is relatively rough compared to that of polishing/finishing processes, typically 0.1 to 0.4 gm. Therefore, the objective of this research is to determine whether controlled dipcoating can be used to improve surface quality of SLA 3D printed parts. Contact profilometer data was collected for SLA 3D printed parts that were dip-coated with varying withdrawal speeds (1 mm/s, 5 mm/s, 0.1 mm/s), printed with different resolutions (0.05 mm, 0.1 mm, 0.2 mm), and angled (0, 15, 30, 45, 60, 75 degrees from vertical). The results suggest that dip-coating is an effective means of improving surface quality, achieving 0.3 to 0.5 micron range of surface roughness. However, validating the effect of withdrawal speed and print resolution as well as how print orientation and geometry can be optimized with dip-coating require further study. The results showed that, in general, dip-coating with faster withdrawal speeds tended to give lower surface roughness, and printing at 0.2 mm resolution gave greatest improvement in surface quality, achieving approximately the same surface quality as the dip-coated 0.05 mm resolution parts. Dip-coating appears to increase surface waviness due to the drainage effect of the dip-coating dominating over the layer by layer print periodicity. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 35).

Design of a FSAE braking system

Mon, 01 Jan 2018 00:00:00 GMT

Design of a FSAE braking system Mora, Luis Alberto MIT Motorsports is a FSAE Electric team at MIT that designs, manufactures, and tests electric formula style racecars to compete in an annual international collegiate design competition. The braking system for the MY18 vehicle developed by MIT Motorsports must enable the driver to consistently and reliably decelerate the vehicle at the maximum rate allowed by the traction limit of the tires. Crucial engineering data needed for a well-informed design, such as the coefficient of friction of the brake pads, motivated the development of a custom brake dynamometer to empirically test for the required data. The brake dynamometer became a very valuable tool eventually being used to select an appropriate brake rotor material and the most effective cooling geometry for the brake rotors. The braking system also integrates a regenerative braking system that works in parallel with the hydraulic braking system for the purpose of recovering braking energy and thus increasing vehicle efficiency. The MY18 braking system, will increase the maximum vehicle deceleration by 50% compared to MY17 and allow for up to 1kW-Hr more of energy recovery compared to MY17 without compromising reliability or consistency. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 42).

Smart shoe force sensor development and analysis for walking gait

Mon, 01 Jan 2018 00:00:00 GMT

Smart shoe force sensor development and analysis for walking gait Luo, Jingya Lauren Foot contact forces are imperative to gait analysis for uses such as elderly rehabilitation and athletic training. Previously developed methods for legged locomotion force detection involved convoluted sensing systems and significant external equipment. This thesis builds upon previous developed smart shoe sensors adapted from the MIT Cheetah robot using pressure sensors embedded in urethane rubber, Smooth-On's Vytaflex® 20. Past work developed accurate material models in Abaqus CAE to simulate foot contacts for compression and shear. This thesis builds upon the FEA models for two sensor sizes to create a simple model to measure torque and contact angle given force measured by the sensor. Using experiments with physical footpads on a CNC mill verified by simulations from Abaqus FEA, we derived models for contact angles between 0 to 15 degrees and rolling movement from -7 to 7 degrees at various compressions. Models successfully derive relationships between roll and contact angle versus force. These models can be used as a jumping point for data analysis using the smart shoe sensor. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 31).

User-centered product design of live-action game experiences

Mon, 01 Jan 2018 00:00:00 GMT

User-centered product design of live-action game experiences Orozco, Eduardo, S.B. Massachusetts Institute of Technology Recently, escape rooms, or live-action physical and mental adventure games that require players to solve puzzles and riddles to complete certain objectives in order to "escape" the room have been very popular. The design of this type of game demands knowledge and expertise in user-oriented product design in a live-action game scenario that engages and challenges participants of all ages. 5 Wits Productions is in the process of producing a live-action game experience based around dozens of "rooms" that each contain physical and mental challenges for small groups of guests to solve. Using the elements of user-centric design such as storyboarding and sketch modeling, a room theme was created and refined to give users a one of a kind experience that transports them to that theme. The theme was based off of the board game "Battle Ship" where players have to sink a ship using balls to defeat the game within the time limit. The final product was a display board ball detection system that showed the players their progress in the game and what areas they needed to hit in order sink the ships. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 48).

Comparing the deflection of different colored glass strips

Mon, 01 Jan 2018 00:00:00 GMT

Comparing the deflection of different colored glass strips Oppenheimer, Or Glass is a material that has been used for both practical and artistic purposes starting as early as the 1st century BC, and the stiffness of the glass affects how easy the glass is to work with. A three-point bending test was performed at 582°C (1080°F) for strips of transparent red, clear, black, transparent blue, and white glass. The deflection of the center point of each strip of glass was measured as the temperature was held constant. A proportional relationship of deflection with time was found for the red and white glass and the deflection of the clear, black, and blue glass was characterized by a parabolic relation. It was found that the red glass is the least stiff, followed by black, blue and clear, which have no statistically significant difference in stiffness, and finally the white glass was found to be the most stiff. These were contrary to the glass workers expectations, which was that black would be the least stiff. This will help glass workers know which colors will act similarly, and what to expect of different colors of glass. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 18).

Career path analysis of professionals selected by MIT undergraduates

Mon, 01 Jan 2018 00:00:00 GMT

Career path analysis of professionals selected by MIT undergraduates Pina, Kyle (Kyle Richard) For current MIT undergrads, life after graduation can seem daunting. With uncertainty about job duration, graduate school, and career paths in general, many undergraduates enter the real world unsure of what the future holds, or if what they have decided to do post-graduation is the "best" option. As such, MIT undergraduates in the Undergraduate Practice Opportunities Program (UPOP) were asked to interview professionals that they believed had jobs they would one day also like to have. This resulted in a large dataset of career paths for an extremely diverse group of individuals, all with their own unique stories and time-lines. This data was filtered, cleaned, and analyzed to gain insight into life after graduation. From the analyzed data it was found that the distributions of durations spent at graduate school, in companies, or in specific job titles were all not significantly different, and the average duration spent in each of these options was 2-6 years, with some noticeable outliers. Overall these analyses showed that there are many options for students in the first 10 years after completing their BS, and there is no clear "correct" option to choose from. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.

An assessment of stingless beeswax as a pattern material in ancient Mesoamerican lost-wax casting

Mon, 01 Jan 2018 00:00:00 GMT

An assessment of stingless beeswax as a pattern material in ancient Mesoamerican lost-wax casting Pitses, Eleni Chrisoula Metal objects were of great cultural significance in pre-Columbian Mesoamerica. Historical and archaeological evidence prove that these items were made by the process of investment casting, or "lost wax" casting, by which a wax model of the object is created, and a ceramic mold is built around it. The wax is melted out to allow for the pouring of the molten metal. Considerable research has focused on the alloy composition of these objects, and some research has been done on the ceramic molds, but little is known about the composition, source, and manufacture of the wax itself. This paper builds upon work by Michael Tarkanian and Dr. Elizabeth Paris, attempting to fill this gap in the literature. Spanish written accounts of ancient Mesoamerican casting processes mention that wax from stingless bees was mixed with copal, or tree resin, and used to form the models for lost-wax casting. Waxes from Mexican stingless bees Melipona beecheii, Scaptotrigona pectoralis, and Melipona yucatanica were considered in this study, in addition to three copals: Bursera copallifera, Protium copal, and Pinus contorta. Thermal data from Differential Scanning Calorimetry revealed no changes in thermal behavior between waxes and their blends with copals, showing that none of the blends considered in this study are miscible. However, hardness testing revealed that the blends of Pinus contorta with Melipona beecheii and with Melipona yucatanica were harder than their respective waxes. This is in line with a Spanish account of the casting process, which mentions that copal was added so the wax may "[become firm and] harden well". Including data collected by Tarkanian and Paris, the most favorable material for investment casting would be Friesomelitta nigra wax mixed with Bursera copallifera, according to the criteria considered in this study. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 43-45).

Self-propulsion of floating objects

Mon, 01 Jan 2018 00:00:00 GMT

Self-propulsion of floating objects Roggeveen, James Interfacial phenomena are of growing interest due to the burgeoning field of microfluidics enabled by recent advances in microfabrication techniques. One particular area of interest in the realm of interfacial effects is the generation of self-propulsion of floating bodies. We examine means of interfacial propulsion employed by floating bodies. Nature utilizes dynamic and quasistatic phenomena to induce propulsion. However, we show that quasi-static propulsion due to manipulation of the shape of the surface, as used by some insects in regions with background curvature, is impossible on a flat surface. We move from consideration of quasi-static phenomena to investigate the use of vertical vibration of a fluid bath as a mechanism to incite self-propulsion of objects at the interface. We build on the work of Pucci et al. (2013), who first noted that fluid lenses floating on an interface driven above the Faraday threshold may be induced to self-propel. Here, we advance the study of Faraday lenses by characterizing the shapes assumed by these lenses as a function of the size of the lens and the driving acceleration, yielding a rich array of dynamics at different driving forces. Seeking to describe the instability and transient behavior of the lenses we develop a model for the elongation of the films as they undergo the Faraday instability, predicting a t14 scaling that is well supported by experimental results. We also test the dependence of the radiation pressure on the bath acceleration by using the radiation pressure to drive motion. Particular attention is given to a Faraday boat and gear, which consist of rigid bodies with unstable fluid lenses pinned inside. The wave-field of the lens is rendered asymmetric due to the asymmetry of the body. We find that we can drive propulsion of these rigid bodies via radiation pressure. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 50-52).

Models of entrainment of human walking

Mon, 01 Jan 2018 00:00:00 GMT

Models of entrainment of human walking Rigobon, Daniel E Stable human locomotion may be described as a non-linear limit cycle oscillator. This claim has been supported through the observation of dynamic entrainment and phase-locking to external mechanical perturbations applied at the ankle. Simple models have been developed in attempts to understand these behaviors, but have been unsuccessful at replicating experimental studies. In this manuscript, an energy-based controller was implemented on a single degree-of-freedom model, adjusting its leading leg angle at heel strike and consequently the energy dissipation of the model. Stochasticity was applied to the controller to simulate the variability which has been observed and quantified in walking. The results indicate that energy control may be responsible for entrainment in human walking, but a revised model may be required to match the experimental coefficients of variation in step duration and velocity. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 39-40).

Design and construction of high-temperature, high-vacuum tensile tester for fusion reactor materials

Mon, 01 Jan 2018 00:00:00 GMT

Design and construction of high-temperature, high-vacuum tensile tester for fusion reactor materials Nick Schwartz, Nick (Nick Raoul) Fusion energy is a promising carbon-free, limitless source of energy that could contribute to mitigating global climate change. One of the critical challenges in realizing fusion energy is the survival of structural materials in the extreme environment of a fusion device. Specifically, materials that surround the 100 million °C plasma must survive high temperatures (>500 °C), intense thermal cycling, transient high heat loads, large structural forces during off-normal plasma events, and exposure to high energy neutrons. Neutron exposure leads to high levels of radiation damage, which results in changes to critical material properties such as ductility and strength. In order to facilitate a better understanding of the effect of radiation on fusion material properties at high temperatures, a novel high-vacuum (<106 torr), high-temperature (<1000°C), tensile testing stand for irradiated specimens was designed and constructed. The test stand was designed to perform tensile testing of structural materials that have been irradiated by 12 MeV protons, which emulate the material response to high-energy neutrons produced in a deuterium-tritium burning fusion device. The specimen will then be heated to 500-1000 °C and tensile tested in high vacuum to eliminate sample oxidation and provide clean measurements. The design and fabrication of the test stand are given in this thesis, and first results from its commissioning are presented. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 24-25).

Image processing for in-situ feedback control of fiber spinning of carbon nanotubes

Mon, 01 Jan 2018 00:00:00 GMT

Image processing for in-situ feedback control of fiber spinning of carbon nanotubes Scigliuto, Siena Carbon nanotubes (CNTs) have gained momentum in industrial applications over the last few decades due to their versatile mechanical, thermal, and electrical properties. Demand for manufactured CNT structures to have precise properties has increased, and with it emerge new manufacturing techniques. This project focuses on an emerging technology that uses an extensional flow apparatus to produce continuous strands of CNTs from a suspension of CNT nanoparticles. The properties of the CNTs produced depend heavily on the configuration of flow rates of the CNT solution and the surrounding solvent. To examine the effects of various flow configurations on a specific property, CNT strand diameter, and provide the basis for a control loop, a LabVIEW virtual instrument (VI) was designed to process experimental images and measure the diameters of the CNT strands produced through an edge detection module. A proof-of-concept experiment was run to do a brief survey of various flow configurations and to test the performance of the LabVIEW system. Several key setup considerations were identified, including lighting of the apparatus to facilitate accurate image processing, and suggestions for improvement of the design of the physical apparatus were identified. The experiment investigated several flow configurations and measured both the average diameter of the CNT strand and the change in diameter as the CNT flows downstream, both of which are important to the control of the flow, where the first one determines the absolute size of the fiber, and the second one relates to the elongational force that the fiber feels. [2] The LabVIEW VI successfully identified and measured the CNT strand 80% of the time, and the unsuccessful cases were examined to determine solutions for improving the VI. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 23).

Rotational speed dependent motor properties

Mon, 01 Jan 2018 00:00:00 GMT

Rotational speed dependent motor properties Suzuki, Aya K The coils of alternating current (AC) motors experience back electromotive force (EMF) at high rotational speeds, which acts against applied voltage and drops motor efficiency steeply. By reducing the magnetic flux surrounding the coil of the stator, back EMF can be reduced and motor efficiency can be maintained at any rotational speed. Several prototypes that take advantage of centrifugal force and moving motor components are created; the prototypes prove that high overall magnetic permeability is achieved at low rotational speeds, and low overall magnetic permeability is achieved at high rotational speeds. In the more successful motor prototype, magnetic flux simulation results show a 43.5% reduction in peak values of back EMF. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 37).

Deriving and verifying a general granular locomotion scaling law

Mon, 01 Jan 2018 00:00:00 GMT

Deriving and verifying a general granular locomotion scaling law Townsend, Stephen (Stephen C.) The complexities of granular materials make modeling the interactions between grains and solid intruders, such as a wheel, incredible difficult. Often, modeling these interactions requires discrete particle simulation methods, such as the Discrete Element Method (DEM), a process that is prohibitively computationally intensive for large systems. The difficulty of modeling granular materials has posed great difficulty for design engineers, particularly those interested in granular locomotion, since there is no way to gain predictive insight into the performance of a given granular locomotion system. A granular locomotion scaling law was developed, which instructs how to scale size, mass, and driving parameters in order to relate dynamic behaviors of different locomotors in the same granular media. For the development of this scaling relationship, a general wheel operating in an ideal Coulombic material was considered. Through dimensional analysis, the system was described as a function of a set of dimensionless numbers which are ratios of the dimensional parameters of the system. From the dimensionless description of the system, a set of scaling families are derived, where each member of a family has the same dimensionless inputs but different dimensional parameters. Then, DEM simulations were used to verify that each member of a given scaling family had the same dimensionless outputs. The DEM simulations found a high level of agreement between the dimensionless outputs of systems in the same scaling family, demonstrating the predictive power of the granular locomotion scaling law. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 59).

Development of a gear shift test setup for hybrid transmission vehicles

Mon, 01 Jan 2018 00:00:00 GMT

Development of a gear shift test setup for hybrid transmission vehicles Sweeney, Katelyn (Katelyn M.) As fuel and efficiency regulations tighten, precise and highly efficient transmission systems are becoming necessities. Previous studies at the MIT Global Engineering and Research (GEAR) Laboratory demonstrated mathematically the ability to improve the shift event via Hall Effect sensing; this study sought to implement those results in practice. To accomplish this, measurements of the physical gearsets, motors, and actuators were implemented into Computer Aided Design (CAD) software in order to design mounts and fixtures. Those mounts and fixtures were then manufactured and implemented into the real setup. In addition, brushless DC motors were utilized and tailored to drive the transmission. The end result was both CAD and physical assemblies that are simple, easy to assemble, and precise to the specifications of the experiment. From this study a proof-of-concept was built, showing that it is indeed possible spatially and physically to build an effective test setup that can support the theoretical needs of the experiment. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 39-40).

Investigating a non-invasive method for determining muscle fiber composition

Mon, 01 Jan 2018 00:00:00 GMT

Investigating a non-invasive method for determining muscle fiber composition Treers, Laura This study aims to explore a new method for analysis of muscle fiber type, using data collected from weightlifts on a leg press. A dynamic muscle model is developed, which utilizes the Descherevskii kinetic theory in combination with a muscle "matrix" model to predict net muscle contraction forces and velocities as a function of fiber type. These relationships are integrated into a dynamic model for lifting a weight, allowing for the derivation of joint trajectories in time, from the molecular properties of muscle. The model-predicted velocity trajectories for the lift are compared with curves obtained experimentally from weightlifting trials. Longer lifts with slower peak velocities indicate higher ratios of slow-twitch fibers, and shorter lifts with greater peak velocities indicate higher ratios of fast-twitch fibers. This idea is supported by both the model results and in experimental trends. With further refinement of experimental protocols, the leg press test has the potential to be a powerful training tool for athletes-both to compare their muscle makeup with other athletes, and to track their own progress over the course of their training. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 39-40).

A strategic framework for effective sketch modeling

Mon, 01 Jan 2018 00:00:00 GMT

A strategic framework for effective sketch modeling Willmer-Shiles, Emma Pearl MIT's undergraduate mechanical engineering capstone class titled 2.009: The product Engineering Process introduces students to the process and tools used by designers to successfully design a product. One of the main skills introduced to students is prototyping as a means of learning about and communicating a product vision. Early stage prototypes, called "sketch models" in 2.009, are made and used in the concept selection phase to explore and validate the design teams concepts. At this point students are new to the design process and unsure of how to develop physical models that are not merely physical representation of their concepts but also tools for exploring, answering design questions and validating a concept. To help students arrive at more effective sketch models this framework has been developed to outline a set of actionable steps that allow students to apply key concepts in the design process to their sketch models. The first portion of the framework focuses on guiding students to arriving at a useful and strategic learning objective for the sketch model. Students are first guided to consider four main areas of concern for concept validation: market, feasibility, scope and customer need in order to target major areas of uncertainty in their concept. To focus on questions that directly relate to a physical model, the next level of consideration focuses on appearance, user experience and functionality of the concept. Lastly, students use the criteria of uncertainty, criticalness to concept validation, and learning potential to prioritize questions for the current design phase. The second portion of the framework suggest the use of examples of other sketch models with similar learning objectives to demonstrate how models have answered similar questions to those that the design team has proposed. Grouped by their physical area of exploration and categorization as "looks like" or "works like" models, a set of examples will conceptually demonstrate how to make their sketch models effective in answering similar design questions. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 35).

Social and academic synergies in MIT's Mechanical Engineering department for empowering twentieth-century Chinese leaders

Mon, 01 Jan 2018 00:00:00 GMT

Social and academic synergies in MIT's Mechanical Engineering department for empowering twentieth-century Chinese leaders Woodard, Joshua Charles Between 1854 and 1954, MIT awarded 734 degrees to students studying abroad from China, which is the third largest number among all American universities during this time period. Within the MIT Mechanical Engineering department, the number of students is well within the hundreds. While these students studied engineering topics uniquely influenced by the developments and needs of twentieth-century China, their courses of study were furthermore influenced by the tutelage they received from a small set of MIT professors willing to cross cultural gaps. These students also had support through affinity groups and made notable impacts on MIT's social landscape during their time at the Institute. Finally, they went on to play significant roles in the subsequent industrialization of China. What, then, were the academic and social environments in the twentieth-century MIT Mechanical Engineering department that led to the successful graduation of students studying abroad from China, and what lessons can be applied to present-day MIT? Based on information from the 1931 MIT Chinese Students' Directory, which provides data on Chinese students from 1877 to 1930, Chinese students' social and academic presence at MIT was quantified, and efforts were made to identify their research advisors and academic mentors, and also to delineate what interpersonal relationships and connections existed between the faculty and the students. In the first decades of the twentieth century, several Mechanical Engineering professors took on more Chinese students than others, most notably, George B. Haven. From the analysis of 20+ theses written by these students between 1877 and 1931, the Mechanical Engineering faculty certainly rallied to support these students as they faced linguistic, cultural, and other challenges during their courses of study. This cohort of Chinese mechanical engineering students was responsible for inventing the first Chinese typewriter, doing the earliest mechanical tests on China-native materials such as ramie and bamboo, and was fundamental to the development of the Mechanical Engineering department at MIT's sister school, Tsinghua University in Beijing. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 41-43).

The benefits of 4WD drive for a high-performance FSAE electric racecar

Mon, 01 Jan 2018 00:00:00 GMT

The benefits of 4WD drive for a high-performance FSAE electric racecar Owen, Elliot Douglas This thesis explores the performance of Rear-Wheel Drive (RWD) and Four-Wheel Drive (4WD) FSAE Electric racecars with regards to acceleration and regenerative braking. The benefits of a 4WD architecture are presented along with the tools for further optimization and understanding. The goal is to provide real, actionable information to teams deciding to pursue 4WD vehicles and quantify the results of difficult engineering trade-offs. Analytical bicycle models are used to discuss the effect of the Center of Gravity location on vehicle performance, and Acceleration-Velocity Phase Space (AVPS) is introduced as a useful tool for optimization. Lap-time Simulation is used to determine the regenerative braking energy available for recovery during a race for RWD and 4WD vehicles. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 81).

Effects of geometry on compliant, stress field force sensor characteristics

Mon, 01 Jan 2018 00:00:00 GMT

Effects of geometry on compliant, stress field force sensor characteristics Romero, Juan (Juan Andrés) This thesis details the development and characterization of multiple geometries for compliant, stress field (SF) force sensors. The goal of exploring these different sensor designs is to begin identification of the geometric properties of SF force sensors that are most optimal for certain loading conditions. This work prioritizes robotic locomotion as the qualifying loading condition, with some considerations towards human locomotion. The stress field force sensors are comprised of a protected array of piezoelectric pressure sensor elements, embedded in an elastomer body. The geometric properties considered are orientation of the sensor elements, and shape and size of the elastomer body. In previous work, cylindrical stress field force sensors were developed and characterized for use in a force sensing smart-shoe. A material model for the elastomer used was also found. Depending on the geometry chosen, voltage values reported by the piezoelectric sensor elements are able to be resolved into forces along three axes, torques about the non-normal axes, and ground contact angle. This computation is done using linear and nonlinear methods, notably linear regression to determine coefficients for force and angle estimator functions and the use of least squares artificial neural networks (LSANN), respectively. The SF force sensors are manufactured using methods developed by Meng Yee (Michael) Chuah of the MIT Biomimetic Robotics Laboratory (BRL). These SF force sensors are able to measure forces over several orders of magnitude, ranging from 10-2 to 103 N depending on the geometric properties of the sensor. Certain SF force sensor geometries provide different outcomes in terms of accuracy, sensitivity, maximum loading, torque measurement, and contact angle measurement. For example, sensors with decreased thickness displayed increased ability to measure smaller forces, and sensors that have outwardly cylindrical elastomer layers are capable of estimating torques. Additionally, of the SF force sensor geometries explored, sensors with hemispherical elastomer shapes had a lower (2-4%) root mean squared (RMS) error in both normal and shear force directions, and were most capable of measuring roll angles. These outcomes will be further detailed in this paper. The creation of these footpad sensors are a part of ongoing work aimed at developing low-cost, durable force sensors for use in the locomotion of dynamic robots. These force sensors would be beneficial in aiding robotic pose estimation and contact detection, thereby allowing traversal of more variable terrain. Implementation of these SF force sensor geometries was conducted by measuring standing and walking forces of the MIT Cheetah 3 quadruped robot and the little HERMES biped robot while each was outfitted with SF force sensing feet. Accurate normal force and roll angle estimates were able to be produced for hemispherical SF force sensors attached to Little HERMES. The MIT Cheetah 3 quadrupedal robot posed challenges to establishing a reliable force comparison. However, the SF force sensors (error of -17 N in flight) performed better then the Cheetah's proprioception (error of ±150 N in flight) when it came to distinguishing between stance and flight. It is postulated that this is due to decreased susceptibility to inertial noise. Future iterations of the SF force sensors developed in this thesis could enable legged robots to have more robust force measurement and pose estimation when undergoing dynamic locomotion. Such capabilities could allow legged robots to achieve performances matching those of animals and take on complex tasks to the benefit of our society. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 91-92).

Design, fabrication, and characterization of split axle skateboard trucks

Mon, 01 Jan 2018 00:00:00 GMT

Design, fabrication, and characterization of split axle skateboard trucks Winter Fox, Terran L A new design for skateboard trucks has been developed and tested in an effort to reduce the uncomfortable vibration experienced when riding a skateboard. The new design interfaces with existing hardware but also features a split axle geometry which allows the left and right wheels to move independently. In order to determine whether the split axle trucks improved rider comfort, the trucks were tested on a skateboard outfitted with sensors that measure acceleration normal to the road surface. Similar measurements were taken with standard skateboard trucks to serve as a control. Multiple trials were run at each of three different test speeds over a set course. Results showed that the majority of the dominant vibration frequencies are in the range of 20-450 Hz for both truck designs. The magnitude of the peak acceleration and the arms were observed to increase faster with speed for the standard truck design, and at the highest speed of 20 km/h the split axle design was shown (with 95% certainty) to have a peak acceleration which was 96 m/s2 lower than that of the standard truck. Overall the results suggest that the new split axle design primarily improves rider comfort during localized vibration events by reducing the peak acceleration that is experienced. This effect, along with a reduction in the measured arms, become increasingly apparent at higher speeds. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 30-31).

Induction heating of firebricks for the large-scale storage of nuclear and renewable energy

Mon, 01 Jan 2018 00:00:00 GMT

Induction heating of firebricks for the large-scale storage of nuclear and renewable energy Ibekwe, Richard Tochi The lack of low-cost, large-scale energy storage is one of the biggest obstacles to the ongoing transition from an energy market dominated by fossil fuels to one dominated by nuclear and renewable energy. Storing energy as heat in firebricks has a number of potential advantages over existing energy storage methods such as batteries and pumped-storage. This work investigated the application of induction heating to firebrick energy storage. The distributions of magnetic field and temperature in firebricks under induction heating were simulated and compared with experiments. It was found that firebricks can be induction heated to high temperatures (>700°C); different material compositions give different temperature responses; and rate of temperature increase is positively correlated with electrical conductivity. It was also shown that, in addition to use in large-scale energy storage, induction heating can be used to measure electrical conductivity and for firebrick quality assurance. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2018.; Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (page 40).

A center of transportation for the city of Algiers

Wed, 01 Jan 1941 00:00:00 GMT

A center of transportation for the city of Algiers Kopp, Anatole Thesis (B.Arch)--Massachusetts Institute of Technology, Dept. of Architecture, 1941.; MIT copy bound with: A resort hotel on Tuckernuck Island / Robert Saunier Lundberg. 1941. -- A country club, design for summer living / John Victor Manget. 1941. -- A refrigeration plant / Charles Julius Müller, Jr. 1941. Accompanying drawings held by MIT Museum.; Includes bibliographical references.

Weight-strength analysis of a modern destroyer with varying frame spacings

Tue, 01 Jan 1957 00:00:00 GMT

Weight-strength analysis of a modern destroyer with varying frame spacings O'Toole Kevin James; Fox, Kenneth; Bleakley, Wilfred Robert Thesis (Nav.E.) Massachusetts Institute of Technology. Dept. of Naval Architecture and Marine Engineering, 1957.; Bibliography: leaf 94.

Electrolyte selection for cobalt-free solid-state batteries

Mon, 01 Jan 2018 00:00:00 GMT

Electrolyte selection for cobalt-free solid-state batteries Hernandez Alvarez, Erick Ivan Lithium-ion batteries are widespread in use due to their thermal stability and high energy density. The most common design uses an organic electrolyte and lithium-cobalt electrode. While safe under typical operating conditions, the use of an organic electrolyte subjects the battery user to certain risks; in particular, Li-ion liquid batteries are explosive when exposed to air and subject to thermal runoff, making them highly sensitive to any physical damage. The use of cobalt also poses a moral concern, as the mining and sourcing of cobalt is geographically restricted and most commonly sourced from countries that have a history of foreign exploitation and child labor. An all solid state battery is suggested as a possible alternative battery that reduces operation risks and maintains similar performance characteristics. Lithium-lanthanum-zirconium oxide is presented as a suitable electrolyte replacement. Coupled with cobalt-free electrodes, this battery design would provide a safer, more responsible battery. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 30).

The design and implementation of a multi-programming virtual memory operating system for a mini-computer

Mon, 01 Jan 1979 00:00:00 GMT

The design and implementation of a multi-programming virtual memory operating system for a mini-computer Parks, Lee Stephen Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Physics; and, (B.S.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1979.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.; Includes bibliographical references.

Harmonic analysis of radial engine torque

Wed, 01 Jan 1936 00:00:00 GMT

Harmonic analysis of radial engine torque Nelligan, Thomas P Thesis (B.S.)-- Massachusetts Institute of Technology, Dept. of General Engineering, 1936.; MIT copy bound with: Science in the newspapres since 1875 / Richard L. Odiorne -- Mechanical aids to computations involving Beer's law / Charles W. Parce -- The production of an alpha brass rod of the minimum copper content / John C. Rowell -- Calculation of friction factors / Donald C. Spencer -- Flow of water through an oil sand / Elmer Hibbard Summersgill -- Effect of flame cutting on low carbon steel / Lee P. Tolman.

A plan for Boston University

Sat, 01 Jan 1938 00:00:00 GMT

A plan for Boston University Irvin, Benjamin W; Hartmann, William E Thesis (B.Arch)--Massachusetts Institute of Technology, Dept. of Architecture, 1938.; MIT copy bound with: An exposition building for the British Empire at the New York World's Fair 1939, Inc. / A. H. Alexander. Accompanying drawings held by MIT Museum.

Evaluation of an aluminum latent heat storage system for the fluoride-salt-cooled high-temperature reactor

Mon, 01 Jan 2018 00:00:00 GMT

Evaluation of an aluminum latent heat storage system for the fluoride-salt-cooled high-temperature reactor Fears, Kendall A. (Kendall Alexander) Latent heat energy storage (LHS) systems offer multiple advantages over sensible heat storage systems in terms of energy density, cost, and cycle efficiency. LHS systems use a phase change medium (PCM) that transfer heat at constant temperature. The use of metallic PCMs allows LHS to be used with high-temperature heat sources, such as the Fluoride-Salt-Cooled High- Temperature Reactor, and the use of a metallic heat transfer fluid (HTF) allows for a high rate of heat transfer. In this thesis, a 0.993 GWh thermal battery (ALTA) comprised of an aluminum PCM and sodium HTF is designed and evaluated in the steady-state. A novel rod design is also proposed to accommodate aluminum expansion as it changes phases. A final capital cost of $25.00/kWh is found, suggesting that ALTA is economically competitive. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 41-43).

Determining the economic value of nuclear power in Spain

Mon, 01 Jan 2018 00:00:00 GMT

Determining the economic value of nuclear power in Spain Fils-Aime, Fabrice A The nature of deregulated energy markets in the United States has forced several nuclear reactors into early retirement over the next few years subjecting the energy market and economy as a whole to uncalculated risk. The unforeseen implications of early retirements of nuclear assets has inspired a cause for concern in Spain where nuclear power faces similar problems. In order to assess the danger that Spain's current market structure incentivizes a premature retirement of nuclear assets and suggest possible implications for carbon emissions, this thesis research project analyzed the economic performance of nuclear power generators in Spain and identified the underlying factors driving it. This was done by calculating the short run profitability of each nuclear reactor. Historical data on the generation, operating costs, and marginal price from the Spanish electricity market was gathered to develop a net profit model. The model was then applied looking forward into the future and revealed an average profitability of +32.24523 E/MWh for the nuclear reactors in Spain. These results point to a positive future for nuclear power in Spain and an incentive to extend the licenses of soon-to-be-retired reactors. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 21).

Cobalt demand : past, present, and future

Mon, 01 Jan 2018 00:00:00 GMT

Cobalt demand : past, present, and future Zele, Alexandra A. (Alexandra Astrid) Cobalt has become more and more popular in the realms of academia, industry, and media due to its integral role in many of the most commonly-used lithium-ion battery cathodes today. Many issues have been evaluated regarding the controversial labor and volatile sociopolitical environments associated with cobalt mining and concerns over the ability of cobalt supply to continue to meet demand, especially the increasing demand due to the electric vehicle revolution. Cobalt is a critical element in a variety of products outside of the battery industry, including: superalloys, hard-facing metals, cutting tools, magnets, chemical catalysts, and pigments. In this thesis, I assessed the criticality of cobalt demand in non-battery sectors with the intention of assessing whether demand of cobalt in its traditional, inelastic sectors will supply be a limiting factor of technological progress by 2030 and by 2050. In order to do so, data was collected on the past and present demands of cobalt in its four primary sectors, outside of batteries: superalloys, cutting tools and hard-facing metals, magnets, and chemical catalysts. Future demand projections were made based on the historic data as well as via a bottom-up approach from industry projections for future product demand and cobalt intensity of products. Substitutes for cobalt in these applications were also investigated and are discussed below. The prices at which substitutes become more favorable than cobalt were also evaluated. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 65-66).

Polymer synthesis for corona phase molecular recognition based on single-walled carbon nanotubes

Mon, 01 Jan 2018 00:00:00 GMT

Polymer synthesis for corona phase molecular recognition based on single-walled carbon nanotubes Sun, Jessica H Current work within Strano Research Group shows that single-walled carbon nanotubes (SWNT) wrapped with methacrylic acid-styrene heteropolymer (MA-ST) can be used for specific corona phase molecular recognition (CoPhMoRe) of Vardenafil, a small molecule drug. This project is a follow-up study on viability of related polymers for CoPhMoRe sensing of five small molecule drugs: Fluticasone, Sumatriptan, Valacyclovir, Vardenafil, and Bupropion. Methacrylic acid-vinylphenylboronic acid (MA-VBA) heteropolymer and acrylic acid-styrene (AA-ST) heteropolymer were synthesized at different monomer ratios and chain lengths. These polymers were suspended with the carbon nanotubes and screened against the five drugs. The (12,1) chirality of MA-VBA-4 and (7,5) chirality of AA-ST-2 were found to be potential candidates for sensing of Fluticasone and Vardenafil respectively. However, MA-ST 8 remains as the superior choice for the specific sensing of Vardenafil. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 32-34).

Vapor-liquid-solid (VLS) growth of lead chalcogenide thin films for infrared sensing applications

Mon, 01 Jan 2018 00:00:00 GMT

Vapor-liquid-solid (VLS) growth of lead chalcogenide thin films for infrared sensing applications Sourakov, Alexandra Andreevna Infrared sensors are used in a variety of applications, from gas and moisture analysers, to human body detection to spectrophotometers. Available IR technology falls on two ends of the spectrum: state-of-art photon detectors are high-quality but expensive and cumbersome due to the need for cryogenic cooling, while thermal detectors are inexpensive but not very sensitive. The goal of this project is to develop materials for uncooled IR sensors with improved performance. Lead selenide (PbSe) detectors are direct narrow band gap materials that have shown promise for relatively inexpensive IR sensing with modest cooling requirements. Adapting the vapour-liquid-solid (VLS) growth mechanism traditionally used for growing nanowires to growing PbSe thin films circumvents the very slow adsorption of a gas phase into a solid surface by introducing a catalytic liquid alloy phase, while simultaneously retaining the stoichiometric control, simplicity, and economy of vapor phase growth. We have set the stage for further experimentation by demonstrating that we can attain a single phase PbSe thin film via VLS growth on an epitaxially matched substrate. We have explored the effects of VLS growth vs. vapor growth on crystal quality as well as the factors that influence diffusion and nucleation rates, such as film thickness, growth temperature, and the presence of a capping layer. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 41-42).

Sintering of small particles

Mon, 01 Jan 2018 00:00:00 GMT

Sintering of small particles Paras, Jonathan (Jonathan Steven) An atomistic approach to modeling the sintering of nanocrystalline alloys has been developed. It has been shown that there exist alloys that exhibit both nanostructured stability and undergo an accelerated sintering process [1], [2]. However, the widespread adoption of such alloys has been limited by a lack of understanding of the processing kinetics that lead to the accelerated sintering phenomena. To better understand the role of surface diffusion, and the effect that system enthalpies of mixing have on inter-particle neck formation, a 3D kinetic monte carlo (KMC) model was proposed to study these phenomena. The results of these simulations demonstrate that positive enthalpy of mixing highlighted as a necessary criterion for nanocrystalline stability in [1], also leads to the fast diffusing elements ability to form the interparticle neck. The condition of lower temperature neck formation by fast diffusing alloy elements is hypothesized to be the mechanism behind which accelerated sintering occurs. The findings in this paper demonstrate that positive enthalpy of mixing alloys can be designed to sinter at lower temperatures and shorter cycle durations if they have adequate solute present on the surface of the particle. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 34-36).

High-resolution transmission electron microscopy of III-V FinFETs

Mon, 01 Jan 2018 00:00:00 GMT

High-resolution transmission electron microscopy of III-V FinFETs Kong, Lisa (Lisa Fanzhen) III-V materials have great potential for integration into future complementary metal-oxide-semiconductor technology due to their outstanding electron transport properties. InGaAs n-channel metal-oxide-semiconductor field-effect transistors have already demonstrated promising characteristics, and the antimonide material system is emerging as a candidate for p-channel devices. As transistor technology scales down to the sub-10-nm regime, only devices with a 3D configuration can deliver the necessary performance. III-V fin field-effect transistors (finFETs) have displayed impressive characteristics but have shown degradation in performance as the fin width is scaled to the sub-10-nm regime. In this work, we use high-resolution transmission electron microscopy (HRTEM) in an effort to understand how interfacial properties between the channel and high-k dielectric affect device performance. At the interface between the channel material, such as InGaSb or InGaAs, and the high-k gate dielectric, properties of interest include defect density, interdiffusion between the semiconductor and dielectric, and roughness of the dielectric - semiconductor interface. Using HRTEM, we can directly study this interface and try to understand how it is affected by different processing conditions and its correlation with device characteristics. In this thesis, we have analyzed both InGaAs and InGaSb finFETs with state-of-the-art fin widths. Analysis of TEM images was combined with electrical data to correlate interfacial properties with device performance. We compared the materials properties of InGaAs and InGaSb and also explored the impact of processing steps on interfacial properties. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 47-50).

Analysis of historical trends in material production and price volatility

Mon, 01 Jan 2018 00:00:00 GMT

Analysis of historical trends in material production and price volatility Kim, Jae Hyun, S.B. Massachusetts Institute of Technology Volatilities generate uncertainties in the market that critically impact the decisions of producers, consumers, and speculators alike. Historical trends in volatility can be studied as a means of better understanding current volatilities and predicting future ones in the industry. This study used the coefficient of variation (CV) as a relative metric to compare the historical production and price volatilities of various materials - 12 metals, cement, and steel - from 1900 through 2015. The long-term (1900-2015) and short-term (1995-2015) volatilities of these materials were quantified, and decades corresponding to periods of warfare and/or economic recession were shown to exhibit highest volatility. To complement the breadth of this approach, aluminum and steel were used as case studies to determine which factors - amongst production, consumption, energy price, and raw material price - drive trends in U.S. material price volatility. Volatility comparison graphs of material price and the factor in question were generated, and the root mean square (RMS) error between the volatilities was taken as a measure of their correlation. Volatilities in both aluminum and steel price were shown to correlate strongest with volatilities in raw material (bauxite and iron ore) price, with volatilities in steel also correlating comparatively with production and consumption dynamics. Overall, this study demonstrated the effectiveness of CV as a quantitative metric to assess historical volatilities and identified key market forces driving these volatilities for the aluminum and steel industries. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 42-44).

Bioconjugation of aminated DNA as a method of rapid polymer library generation for Corona Phase Molecular Recognition

Mon, 01 Jan 2018 00:00:00 GMT

Bioconjugation of aminated DNA as a method of rapid polymer library generation for Corona Phase Molecular Recognition Harris, Jasmine K An experimental study was performed to determine the effects on Corona Phase Molecular Recognition (CoMoRe) of bioconjugating a host of small molecules to DNA wrapped single-walled carbon nanotubes. In addition, the study observed the effects of the DNA sequence length on the subsequent effectiveness of the small molecules to alter the corona phase. The conjugation of small molecules was shown to alter both the intensity and the position of the fluorescence and absorbance profile. The length of the DNA sequence was found to change the small molecule's ability to alter the fluorecence spectra of the wrapped nanotubes. The EDC/sulfo-NHS reaction was done to conjugate the small molecules to two identical DNA sequences with varying lengthes. Through the methods of ultraviolet-visibile-near infrared absorption spectroscopy, near infrared fluorescence spectroscopy, and high-performance liquid chromatography characterization and structural analysis were performed. The results showed the successful conjugation of the small molecules to the amino-modified DNA and an alteration in the corona phase. The small molecules were found to bind to the DNA at multiple locations and the length of the sequence was found to have an effect on the corona phase. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 39).

The effects of regulatory constraints on the deep ocean mining industry.

Sat, 01 Jan 1977 00:00:00 GMT

The effects of regulatory constraints on the deep ocean mining industry. Antrim, Lance Thesis. 1977. Env.E.--Massachusetts Institute of Technology. Dept. of Ocean Engineering.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.; Bibliography : leaves [67]-72.

Fault-tolerant passively integrating in-vivo dosimeters for feedback-enabled proton therapy (IF²D, or integrating feedback F-center dosimeter)

Mon, 01 Jan 2018 00:00:00 GMT

Fault-tolerant passively integrating in-vivo dosimeters for feedback-enabled proton therapy (IF²D, or integrating feedback F-center dosimeter) Iturbide, Rossana Current dosimeters used in radiotherapy for cancer treatment fail to distinguish between radiation received by the targeted tumor and the surrounding healthy tissue. The Integrating Feedback F-center Dosimeter is designed to be fault-tolerant, with the capability to distinguish the radiation dose received between a targeted tumor and surrounding tissue. To provide a proof of concept of the IF²D, five alkali halide salts will be irradiated by a tandem electrostatic proton accelerator. These salts, (NaCl, NaI, NaBr, NaF, CsF), were chosen for their f-center properties which enable a direct conversion between the wavelength of the irradiated salt i.e. color change, and the expected radiation dose. We expect that analytical calculations between wavelength and expected radiation dose will correlate with experimental data. A direct conversion will enable the doctor to determine how much radiation the salt has received and therefore how much radiation dose the tumor itself has received. As a result, the patient will require less exposure time, and less radiation treatments, thus reducing the probability of obtaining secondary cancers. The following paper outlines the initial procedures taken to irradiate the selected salts and theoretical calculations that we expect to parallel future experimental data. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2018.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 22-23).

Quantifying measurement uncertainties of MIT Research Reactor's new digital nuclear safety system

Mon, 01 Jan 2018 00:00:00 GMT

Quantifying measurement uncertainties of MIT Research Reactor's new digital nuclear safety system Parus, Rachel (Rachel Elizabeth) Accurate measurement of reactor power is one of the most important requirements in order to ensure the reliable and safe operation of a nuclear reactor. The MIT research reactor, (MITR-II), currently has outdated analog reactor period and power monitoring instruments that are difficult to read and in need of frequent adjustment. Replacing these old monitors with digital ones is an important step in continuing to ensure MITR-II's reliable and safe operation. Four Mirion DWK 250's, wide-range neutron ux monitors that provides reactor period and power level monitoring, have been assembled and connected to the MITR for parallel testing. Before they can fully replace the existing analog monitors, the accuracy of measurement of the DWK's must be quantified to meet the performance requirements described in the Safety Analysis Report (SAR) and obtain Nuclear Regulatory Commission (NRC) approval. As part of the calibration tests, reactor power measured by the four DWK channels was recorded and compared to the reactor thermal power obtained through calorimetry calculations. The measurement uncertainties of the four DWK channels were quantified by taking into account the statistical uncertainties of data recorded over two separate operating periods in 1 minute intervals after thermal and xenon equilibrium were reached. The reactor neutron power measured by each channel was found to t a normal distribution during steady-state operation, and the 3 values, 99.7% condence level, were found to be less than 1.6% of the average power detected for each DWK indicating each device's high level of precision. The average percent error between DWK and thermal power was determined to be 4% for each DWK, thus a thorough review of calibration procedures should be performed to ensure an accurate indication of reactor power. Furthermore, as the setpoints of the DWK's may be adjusted over the core cycle of the reactor, the relationship between shim blade height and DWK adjustment was also determined by parallel testing and modelling. The adjustment of each of the DWK's over a fuel cycle was found to be minimal. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2018.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (page 53).

Developing modern graphite exponential pile experiments to augment reactor physics education

Mon, 01 Jan 2018 00:00:00 GMT

Developing modern graphite exponential pile experiments to augment reactor physics education Gale, Micah D. (Micah David) Reactor Physics is not always an intuitive subject for students to understand. When nuclear engineering was beginning as a field it was common for students to complete measurements on sub-critical reactors, which could not sustain a fission chain reaction, in order to develop student intuition. The Massachusetts Institute of Technology has one such reactor, a graphite exponential pile, which went unused for decades. In this thesis the MIT Graphite Exponential Pile was returned to experimental operation, and a prototypic student experiment was completed. The material buckling was found by indium foil activations completed with a plutonium-beryllium source in the pile. From the experimental results it was calculated the pile would have to be a cube with sides that are 5.42m long to become a critical reactor. This proof of concept experiment makes it possible for mens et manus based education at MIT for reactor physics. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2018.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 39-40).

Design and analysis of low-cost x-ray imaging system incorporating consumer camera imaging

Mon, 01 Jan 2018 00:00:00 GMT

Design and analysis of low-cost x-ray imaging system incorporating consumer camera imaging Abel, Logan B X-ray imaging is a core component of our modern medical diagnosis arsenal in combatting a broad range of disease. X-ray imaging allows medical professionals to see the internal structure and layout of the human body, and in this way allows for the visualization of unseen ailments. A current "disease of poverty" which is the target of this study is tuberculosis, a lung bacteria which is visible on x-ray imaging. X-ray imaging is a well known and used technology, yet x-ray imaging remains very expensive and unwieldy for use in less-developed regions of the world. Within the last three to four decades, the world has seen a massive explosion in consumer camera technology development, largely driven by circuit miniaturization, and this has led to cheaper and higher resolution cameras being produced. X-ray images themselves rely on a material to turn x-rays, the photons which pass through the person in medical imaging, into electrical signals which can be read by a computer. This collection of x-ray photons can be done through the coupling of a scintillating screen and a camera which images the scintillating screen to create an x-ray image. This study explores this particular method of x-ray imaging which is likely to be cheaper than existing methods of x-ray imaging, yet also likely yields images of poorer resolution and contrast distinction in x-ray images. The theoretical components necessary to setup such a system in the most efficient manner possible were analyzed, taking into consideration safety and finance constraints. The imaging capabilities of a Nikon D810 (f/1.4, 50 mm lens) and iPhone 5S (f/2.2 lens), higher and lower quality cameras respectively, were analyzed using three scintillating screens, the MCI Optonix DRZ High, Scintacor DRZ Medium, and Scintacor DRZ Ultrafine screens, to capture the x-rays produced from a 14 mA 100 kV x-ray tube. It was found that the Nikon D810 coupled with the MCI Optonix DRZ High Screen produced results similar in performance to current medical imaging, and the iPhone 5S images were too noisy to be conclusive. Further work should go into developing a more finalized and standalone product that can be tested in clinically important settings, as this study does provide the proof-of-concept framework for this to be possible. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2018.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 52-54).

Geometric and optical transformations of supramolecular host-guest amphiphiles

Mon, 01 Jan 2018 00:00:00 GMT

Geometric and optical transformations of supramolecular host-guest amphiphiles Lo, Cynthia Tsien Molecular self-assembly has been an area of recent interest due to its application in a variety of important contexts including drug delivery, regenerative medicine, energy applications, and others. Simultaneously, host-guest chemistry provides a robust and powerful mechanism for inducing switching on the molecular level. In this research, we demonstrate a new platform that combines molecular self-assembly of an amphiphilic chromophore guest molecule with its host molecule counterpart, CB[8] in water. We find that upon addition of CB[8] to a solution of the amphiphilic guest molecule, host-guest complexation occurs and a transition in the morphology of the observed self-assembled nanostructures occurs. Here we present the synthetic route to our amphiphilic guest molecule, in addition to the nanostructural characterization of the supramolecular nanostructures and the host-guest nanostructure by TEM, UV-Vis, and fluorescence spectra. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 30-31).

Introduction of the reduced surface energies at zero absolute temperature.

Sat, 01 Jan 1977 00:00:00 GMT

Introduction of the reduced surface energies at zero absolute temperature. Daryanian, Bahman Thesis. 1977. B.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.; Includes bibliographical references.

Engineering a human Factors analysis of a novel one Atmosphere Diving Suit (ADS) elbow joint

Mon, 01 Jan 2018 00:00:00 GMT

Engineering a human Factors analysis of a novel one Atmosphere Diving Suit (ADS) elbow joint Ingraham, David M. (David Michael) An Atmospheric Diving Suit (ADS) is a one person anthropomorphic submersible which is used to facilitate undersea work while keeping the diver/operator at atmospheric pressure thus removing them from the harmful physiological effects associated with diving at depths. Most ADS in use today have limited range of motion/mobility due to the combination of rotary joints utilized. The joint discussed in this thesis differs from rotary joints, widely in use today, in that it is a bellows type joint which allows sixty degrees of motion in plane. The engineering required to allow this joint to operate under pressure is to maintain a constant volume as it travels throughout its range of motion. If volume changes while subjected to pressure from the ocean the joint will seek the position with the smallest volume. Energy would be required to move the joint from the position associated with the smallest volume, making the joint a poor design which could fatigue the operator. This thesis will explain the engineering behind maintaining the volume through a range of motion. Material selection of the joint membrane is a critical component. When designing the joint to maintain constant volume throughout its range of motion an assumption of a perfectly flexible and inelastic material is made. We discuss the ramifications associated with a membrane which is not perfectly inelastic. This thesis continues the work that has been completed in conjunction with a Small Business Technology Transfer (STTR) contract funded by the Office of Naval Research (ONR) between the Massachusetts Institute of Technology and Midé. The elbow joint prototype, developed and manufactured by Midé, was tested in a rig, designed and built at MIT, consisting of a water tank with the joint completely submerged. Range of motion for 15 subjects was captured using image processing software and qualitative interviews were conducted to capture the experience for users with different anthropomorphic measurements. A human factors analysis was performed which proved that the joint operated as designed in a shallow water environment. A prototype ADS consisting of rotary and bellows joints is also proposed. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 81).

An automatic, multi-fidelity framework for optimizing the performance of super-cavitating hydrofoils using Gaussian process regression and Bayesian optimization

Mon, 01 Jan 2018 00:00:00 GMT

An automatic, multi-fidelity framework for optimizing the performance of super-cavitating hydrofoils using Gaussian process regression and Bayesian optimization Parker, Benjamin W. (Benjamin Wade) Computer automated design of complex physical systems is often limited by the computational resources required for the high precision solvers. Determining an optimum design necessitates high accuracy simulations due to the multi-dimensional design space and the interconnectedness of the constraint and objective quantities. This paper will present an automated framework for iterating through a design loop that includes both physics-based computer simulations and surrogate model training using machine learning techniques. To alleviate the computation burden and efficiently explore the design space, a surrogate model for each quantity of interest that cannot be found deterministically will be utilized. Further reduction of the computational cost is accomplished by utilizing both low- and high-fidelity data to build the response surfaces. These response surface models will be trained using multi-fidelity Gaussian process regression. The models will be iteratively improved using Bayesian optimization and additional high-fidelity simulations that are automatically initiated within the design loop. In addition, Bayesian optimization will be used to automatically determine the optimum kernel for the Gaussian regression model. The feasibility of this framework is demonstrated by designing a 2D super-cavitating hydrofoil and comparing the optimum shape found with a known benchmark design. This automated multi-fidelity Bayesian optimization framework can aid in taking the human out of the design loop, thus freeing manpower resources and removing potential human bias. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 99-100).

Enabling tactical autonomy for unmanned surface vehicles in defensive swarm engagements

Mon, 01 Jan 2018 00:00:00 GMT

Enabling tactical autonomy for unmanned surface vehicles in defensive swarm engagements Campbell, Adam Michael This research incorporates practical applications of marine vehicles with robotics control theory to reduce the vulnerability of allied assets to asymmetric warfare. This work utilizes distributed decentralized multi-objective optimization in the Mission Oriented Operating Suite with Interval Programming (MOOS-IvP) to enable a number of simulated unmanned surface vehicles (USV) to provide defense for a high value unit (HVU) against fast attack craft (FAC) aggressors. The primary objective is to enable a swarm of defending vehicles to protect the HVU and successfully counter a swarm of aggressors with the ability to adapt to changing situations. This research makes it possible for autonomous defenders to react according to variables such as number of defenders, number of aggressors, known kinematic capabilities of defenders, perceived kinematic capabilities of aggressors, and positional distribution of aggressors. A theoretical framework is first described for analyzing the engagements based on game theory by constructing the defense scenario as a three-party differential game. MATLAB is then utilized to demonstrate optimal solutions to this scenario as an application of game theoretical guidance, which was developed for use in missile guidance systems. Algorithms and behaviors are then presented to demonstrate that the multi-objective optimization in MOOS-IvP approaches the optimal solutions in the vehicles' autonomous response during engagements consistent with the three-party differential game. Finally this work presents MOOS-IvP simulation data to demonstrate autonomous tactical decision-making in more realistic engagement scenarios. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 91-93).

Combined tensile-compressive biaxial loading of Li-ion battery components

Mon, 01 Jan 2018 00:00:00 GMT

Combined tensile-compressive biaxial loading of Li-ion battery components Byrd, Nathaniel J. (Nathaniel Joseph) Lithium-ion batteries under a mechanical load can develop failures in the internal multi-layer structure. Due to the flammable materials required for construction, the safety of the battery has been in question since it was first developed. Internal failures can create a short circuit which may lead to thermal runaway, resulting in fire and sometimes the explosion of the battery. Due to the increasing use of lithium-ion batteries in military and consumer products, the number of incidents involving batteries has also risen and with it a growing concern for safety. The larger batteries required for unmanned vehicles and electric vehicles increase the potential for damage due to a battery fire aboard a ship or a battery damaged in a collision. This thesis investigates the failure mechanism of internal lithium-ion battery components when subject to a constant out-of-plane compression while applying and increasing a decoupled in-plane tension until failure. This thesis also describes the methods used to optimize the mechanical system designed to apply constant compression while increasing tension. The results will be used to characterize and anticipate the effect of lateral compression on the failure load of lithium-ion battery cells. The existing microstructural based finite element model can be modified to the experimental conditions in this thesis in order to compare the experimental and modeled results. This comparison will be used to refine and validate the micro model and ultimately bring us closer to improving the design of lithium-ion batteries. Experimental results showed there is a quantifiable relationship between the amount of pre-compression internal battery components are exposed to and the maximum failure load. In the tested 0 to 30 MPa compression range was a 40% reduction in fracture displacement and a 20% reduction in load displacement. The change in failure order, predicted by the micro model was validated by this experimental data. However, failure did not occur in the area of compression which indicates friction due to the compression had a significant effect on testing therefore a design to eliminate friction was proposed. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 62-63).

Making space : pedagogical interventions to foster equity in introductory maker education

Mon, 01 Jan 2018 00:00:00 GMT

Making space : pedagogical interventions to foster equity in introductory maker education Weishaar, Katherine (Katherine R.) The maker movement has spread widely among both adults and children, but its recent integration into K-12 education has forced makerspace coordinators to examine their work through a new lens. Experienced makers need little beyond safety training to get started making their own projects, but new makers, particularly young students, need more. Without properly scaffolded introductory activities, inexperienced students quickly become discouraged and opt-out of maker activities. This thesis explores possible pedagogical guidelines for introductory activities that create more inclusive educational makerspaces. Education theorists and maker educators consistently express a need to support beginners, but the exact type of support differs. Some foster equity by choosing non-gendered introductory projects that can be easily modified for personal customization. Many suggest that the most useful support comes from creating a maker community, typically by leveraging both peer interactions and mentor relationships. In the workshop I taught, I tested my lesson plan both with and without explicit emphasis on peer feedback. The sections with an emphasis on peer feedback were more creative, social, and willing to ask questions than the sections without it. Though their techniques for creating community may differ, educators must be aware of the psychological barriers that keep students from making. Some students claim that they lack certain skills, whether technical or creative, that are necessary to make an original project. Others believe that makerspaces are only for "smart people" or "engineers" and do not view themselves as part of those groups. And still others are eager to get started, but simply lack the economic privilege necessary to continue work with expensive tools at home. All of these students need different types of support, but they will all benefit from a community where they view their mentors and peers as sources of inspiration and feedback instead of as unsurpassable competition. Thesis: S.B., Massachusetts Institute of Technology, Department of Architecture, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 63-64).

Power at Battersea : understanding post-industrial Britain through an art deco monolith

Mon, 01 Jan 2018 00:00:00 GMT

Power at Battersea : understanding post-industrial Britain through an art deco monolith Sanchez, Brandon (Brandon A.) In the modern age, a building serves a purpose beyond that of its intended architectural function. This is especially true of famous buildings, which become important as icons independent of their physical presence. When a building reaches a certain level of fame, its symbolic significance shifts not only as a result of its programming, but as a result of its political, social, and cultural context. These buildings often long outlive their original purposes. When this occurs, architects strive to find a way to best honor that building's history in their redevelopment. This thesis explores the symbolic history of one building in particular, Battersea Power Station in London. Constructed in a long period from 1929-1955, Battersea entered the cityscape in controversy. In less than a century Battersea has gone from environmental demon to beloved architectural icon, from the symbol of a nation's vulnerabilities to the symbol of a nation's ability to oppress. Its meteoric rise to international visibility in the 1970s led to its depiction in countless works of film, television, and other artistic media, each with their own interpretation of the building's significance. The new millenium has brought with it the opportunity to redevelop Battersea. However, its current redevelopment has brought with it a controversy comparable to that which mired its construction nearly a century ago. In a key period since the early 20th century, Britain has seen its industrially-fuelled empire collapse and its international standing fall. The rise and fall of Battersea can help trace Britain's national anxieties over the course of this post-industrial age. In so doing, Battersea Power Station indicates the power that architecture has not only to signify its socio-political context, but to influence it as well. Thesis: S.B., Massachusetts Institute of Technology, Department of Architecture, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 117-123).

Inclusive : a human centered approach to accessible architectural design

Mon, 01 Jan 2018 00:00:00 GMT

Inclusive : a human centered approach to accessible architectural design Liu, Jenny, S.B. Massachusetts Institute of Technology Architecture is about creating spaces for people to live their best lives, yet architecture can be disconnected from the people most directly impacted by its work. According to a survey in 2015, only 2.6% of non-architects feel that the profession does an excellent job of understanding the needs and desires of those living and working in our buildings. As such, occupants suffer spaces that are uncomfortable and sometimes unusable; in particular, people with disabilities are often restricted to certain spaces because most places are designed without any consideration of their needs.. Universal design, a new concept in architecture, asks how can we design in a way that makes life easier, healthier, and friendlier for all by putting people with disabilities on an equal playing field with other types of users. Universal design draws from accessibility standards and design principles to create environments that can be used by as many as possible without specialized design accommodations. Integrating accessibility and universal design principles in architecture could enrich our understanding of a space and add a new layer of spatial experience for everyone. The purpose of this thesis is to investigate what makes spaces inclusive and usable for those with disabilities, how we can design for a broader population, and whether we should embrace universal design ideas. This thesis will use a review of the history and current practices of universal and accessible design and precedent studies to inform a design process focused on understanding the users and their experiences in order to maximize usability. Then, this thesis will apply this knowledge by assessing the MIT Stratton Student Center and the Ray and Maria Stata Center using observations and surveys to find the gap between their designs and universal design principles. This analysis will provide findings and recommendations of how universal design can be better incorporated in public spaces on MIT's campus. Thesis: S.B., Massachusetts Institute of Technology, Department of Architecture, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 72-74).

Folding fan fac̦ade : designing an actuated adaptive fac̦ade system for fine-grain daylight control

Mon, 01 Jan 2018 00:00:00 GMT

Folding fan fac̦ade : designing an actuated adaptive fac̦ade system for fine-grain daylight control Kim, June,S.B.Massachusetts Institute of Technology. In architecture, natural light is one of the main factors to consider when designing a building or a room. A building has to be designed in such a way to allow the right amount of natural light in which influences the building occupants' visual and thermal comfort level. Curtains, blinds, shades, or shutters are the most common static shading methods currently used to regulate the amount of sunlight coming into a room. However, traditional blinds or shades cannot be customized with respect to fine-grain localized control, which can result in suboptimal indoor lighting levels when the blinds or shades are down. While static window treatments are practical low-cost options, they cannot offer the level of adjustment that dynamic shadings can provide. Majority of the time, occupants of a room have the freedom to adjust the shades; however, the shades are often left in one position since occupants are not willing to constantly adjust the shutters every time the outside environmental conditions change. Unlike traditional blinds, adaptive fac̦ades are designed to automatically adjust positions depending on the environmental changes or have the ability to be fine-grain controlled by the occupant. Because of the ability to respond to fluctuating weather conditions, adaptive fac̦ades can provide optimal indoor day lit space. The purpose of this thesis is to design and build a proof-of-concept prototype of a folding fan-shaped actuated adaptive facade system. Because of the scope of this thesis, the prototype is designed to fit in one of the windows at McCormick Hall instead of a full scale building fac̦ade. There are 13 fan-shaped shades units that can be individually controlled to reduce direct sunlight coming into the indoor space. The results demonstrate that this technology can be designed and built with a modest budget and commonly available tools to achieve high quality results for customized daylight control. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Thesis: S.B., Massachusetts Institute of Technology, Department of Architecture, 2018; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 57-58).

3D geographic model vs street view panorama a cognitive study on navigation in different Google maps representations

Mon, 01 Jan 2018 00:00:00 GMT

3D geographic model vs street view panorama a cognitive study on navigation in different Google maps representations Gu, Tianxia Throughout history, different tools have been invented to help people navigate in space. The different tools use different modes of representation as abstractions of 3-dimensional space. Two of the representations used in Google Maps, a modem wayfinding technology, are the 3D geographic model mode and the street view panorama mode. In this thesis, we explore the wayfinding behaviors of people in those two representations by performing experiments. We find that each representation mode is advantageous for a different type of city structure (e.g., regular grid vs. irregular streets). Each representation mode is also preferred by people according to their spatial processing type preference and the wayfinding task type they perform. After evaluating our findings from the experiments, we propose a design of a new representation with facade images augmenting a 2D satellite map. We believe this design incorporates the advantages of both representations studied. Thesis: S.B., Massachusetts Institute of Technology, Department of Architecture, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 48).

Design for infectious disease control in the developing world : the power of natural ventilation

Mon, 01 Jan 2018 00:00:00 GMT

Design for infectious disease control in the developing world : the power of natural ventilation Anderson, Abigail M Contaminated particles in hospitals can spread from infected patients to those who are hospitalized for non-disease-related reasons. The reputation of hospitals, especially in the developing world, as places where diseases are spread rather than cured necessitates design strategies focused on stopping or controlling disease spread among patients. In this thesis, I examine the potential of architectural layout, among other factors, to reduce the spread of contaminants through passive ventilation strategies. Using Computational Fluid Dynamics, I propose a system of hospital rooms which minimizes contaminant spread among patients while maintaining comfortable airflow rates. Thesis: S.B., Massachusetts Institute of Technology, Department of Architecture, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 55-56).

Next generation probabilistic prediction model for submarine propulsion shaft life

Mon, 01 Jan 2018 00:00:00 GMT

Next generation probabilistic prediction model for submarine propulsion shaft life Huynh, Daniel Duc Cong With the development of the U.S. Navy's new COLUMBIA class ballistic missile submarine, the Navy plans to implement a new, longer operational inspection interval for the propulsion shaft system, attempting to double the current 6-year inspection interval for the OHIO class of submarine it is replacing. However, an initial study conducted suggests unsatisfactory levels of failure at this interval due to corrosion fatigue, although with a high level of uncertainty. This thesis addresses that uncertainty by developing a more robust probabilistic model for submarine propulsion shaft reliability in order to more accurately predict probabilities of failure. To improve upon previous efforts, all the components and failure modes of the propulsion shaft were first identified. While the most likely scenario involves water ingress and a wetted propulsion shaft leading to corrosion, pitting, and cracking, other factors that could contribute to shaft failure include damage during installation or failure of cathodic protection systems. Using literature and data gathered during visits to Portsmouth Naval Shipyard (PNSY), these failure modes were approximated with appropriate relationships and statistical distributions and ultimately combined to form a complete probabilistic model of the propulsion shaft system, including all the expected components and the best physics available. Additionally, while this model was designed with extension to the COLUMBIA class of submarine in mind, it can be tailored and easily modified to apply to a broad range of shafting systems, including other classes of submarines, conventional surface ships, and even offshore platforms. The GoldSim program was used as the vehicle for the model, with failure probabilities for the submarine shaft predicted using Monte Carlo simulations. To calibrate the model, outputs from the probabilistic model were compared against hypothetical shaft inspection data, adjusting distributions and variables as appropriate to match target values. While the model used the OHIO class submarine as its baseline, it is expected that the new COLUMBIA class shafting system will use similar materials and have a similar configuration. These inspections have typically taken place at around the 6-year operational interval, but the calibrated model can be used to predict propulsion shaft failures at a range of inspection intervals. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 81-85).

Multipath arrival tracking for marine vehicles utilizing pattern recognition

Mon, 01 Jan 2018 00:00:00 GMT

Multipath arrival tracking for marine vehicles utilizing pattern recognition Fouquette, Jordan William In recent years, interest in the Arctic Region has been steadily growing as it has become more accessible due to continued ice recession. This increased accessibility opens up the possibility for nations to take advantage of the region's abundant resources and trade routes thereby increasing military, political, and commercial interest. The extreme temperatures and significant ice cover in this region have created a unique and challenging acoustic environment. At increased distances, individual acoustic ray path data becomes inconsistent due to improper ray path identification and fading. Marine vehicles have the ability to overcome these challenges and increase contact tracking capabilities by taking advantage of the patterns associated with these multipath arrivals. Through the use of pattern recognition, a multipath arrival tracking algorithm was developed to utilize the unique characteristics associated with each individual ray path for long range tracking purposes. This tracking algorithm analyzes the amplitude and arrival time patterns amongst all individual ray paths in order to accurately identify each ray path as scattering and fading occurs, thereby increasing range-tracking capabilities. This becomes especially useful in the Arctic Region as contacts of interest can be tracked regardless of their position above, below, or within the Beaufort Duct- a newly discovered sound duct from 100 to 200 meters depth. Simulations covering the numerous depth combinations of sources and receivers with respect to the Beaufort Duct illustrate the difficulty in contact tracking within this harsh environment and highlight the effectiveness that is presented by utilizing multipath arrival data. The developed algorithm takes advantage of these unique patterns in order to provide a unique tracking capability for marine vehicles to employ. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 123-124).

Time-optimal multi-waypoint mission planning in dynamic flow fields

Mon, 01 Jan 2018 00:00:00 GMT

Time-optimal multi-waypoint mission planning in dynamic flow fields Ferris, David, S.M. (David Lee). Massachusetts Institute of Technology This thesis demonstrates the use of exact equations to predict time-optimal mission plans for a marine vehicle that visits a number of locations in a given dynamic ocean current field. The missions demonstrated begin and end in the same location and visit a finite number of locations or waypoints in the minimal time; this problem bears close resemblance to that of the classic "traveling salesman," albeit with the added complexity of a continuously changing flow field. The paths, or "legs," between all goal waypoints are generated by numerically solving exact time-optimal path planning level-set differential equations. The equations grow a reachability front from the starting location in all directions. Whenever the front reaches a waypoint, a new reachability front is immediately started from that location. This process continues until one set of reachability fronts has reached all goal waypoints and has returned to the original location. The time-optimal path for the entire mission is then obtained by trajectory backtracking, going through the optimal set of reachability fields in reverse order. Due to the spatial and temporal dynamics, a varying start time results in different paths and durations for each leg and requires all permutations of travel to be calculated. Even though the method is very efficient and the optimal path can be computed serially in real-time for common naval operations, for additional computational speed, a high-performance computing cluster was used to solve the level set calculations in parallel. This method is first applied to several hypothetical missions. The method and distributed computational solver are then validated for naval applications using an operational multi-resolution ocean modeling system of real-world current fields for the complex Philippines Archipelago region. Because the method calculates the global optimum, it serves two purposes. It can be used in its present form to plan multi-waypoint missions offline in conjunction with a predictive ocean current modeling system, or it can be used as a litmus test for approximate future solutions to the traveling salesman problem in dynamic flow fields. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 43-49).

Analysis of consistently poor work estimates in U.S. submarine availabilities

Mon, 01 Jan 2018 00:00:00 GMT

Analysis of consistently poor work estimates in U.S. submarine availabilities De Vlaming, Sjaak André The maintenance of a warship requires an involved combination of scheduling, funding, and execution. For one finite maintenance period, known as an "availability," a small setback in one of these areas can have a significant deleterious effect on the availability as a whole. Compounded and obscured by complexity, the root causes of such setbacks may remain unresolved and recur within the same availability or in one that follows, resulting in cumulative cost increases and schedule delays. The United States Navy has a strong incentive to better understand availability execution. In support of that objective, this thesis investigates man-hour cost data from 57 submarine availabilities across all four public naval shipyards, spanning 315 ship systems, from December 2006 to December 2017. The results of this thesis are best understood in two parts: the first is an observation of system population characteristics, and the second is a multiple linear regression analysis. The first part identifies nine specific submarine systems for which work is consistently over- or underestimated in a majority of availabilities, and also partitions the data to gain insights about the performance of categorical subsets, such as a particular shipyard, availability type, or period in time, compared to the aggregate. These results include a "tier ranking" of the systems whose improvement would yield the greatest benefit for cost. The second part yields two different multiple regression models of the data to create revised estimates for what is known as "New Work," which is unexpected work whose scope is notoriously difficult to predict. Both models result in significantly higher error than that which exists without them, invalidating multiple linear regression analysis as a path to gaining insights about availability performance. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 61-62).

Risk-based treatment of uncertainty in trade space exploration : application via Monte Carlo simulation on a manned, mini-submersible model

Mon, 01 Jan 2018 00:00:00 GMT

Risk-based treatment of uncertainty in trade space exploration : application via Monte Carlo simulation on a manned, mini-submersible model Dadds, Nicholas Andrew In design, modeling and simulation are commonly used to answer questions of interest as it is both inefficient and expensive to physically build and evaluate numerous possibilities. Any modeling effort aims to build the simplest model while capturing the real-world trends appropriately. When modeling highly complex systems or pushing technological bounds, variables in the model will possess elements of uncertainty. In a trade space approach, different design combinations may exhibit different uncertainty profiles. Omitting uncertainties in the modeling effort can bias design combinations in the overall trade space in terms of capability and cost as well as misrepresent the value of tradeoffs between designs. Therefore, if the uncertainties are not represented, the decision-maker is accepting an unknown level of risk when selecting a design. This thesis proposes that uncertainty in early stage design is not well represented, despite its playing a major role in a system's ultimate success. This research explicitly accounts for uncertainty in model inputs via probability distributions instead of simply applying "best estimate" deterministic values. These distributions are sampled via Monte Carlo simulation to generate uncertainty profiles for different design combinations, thereby increasing the validity of the model outputs. This approach for capturing the implications of uncertainty in early stage design allows for a more accurate representation of design risk. Ultimately, the deterministic design points in the trade space are quantitatively and qualitatively evaluated against the design points incorporating uncertainty. Understanding that model outputs can only ever be as good as model inputs, the exploration of the effect of uncertainty on the design trade space is important. An example of Trade Space Exploration for the conceptual design of a manned, mini-submersible is used to demonstrate an approach for quantifying and visualizing uncertainty to inform decision-making. This case study suggests that visualizing risk at the system level in a typical performance versus cost context is valuable. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 87-88).

A design for a parish church

Thu, 01 Jan 1903 00:00:00 GMT

A design for a parish church Hood, Raymond M. (Raymond Mathewson), 1881-1934 Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1903.; Accompanying drawings held by MIT Museum.

Thermal imaging of quenched microstructural evolution in steel alloys

Mon, 01 Jan 2001 00:00:00 GMT

Thermal imaging of quenched microstructural evolution in steel alloys Zacharia, Nicole, S.B. Massachusetts Institute of Technology A method was devised for quenching undercooled samples of Fe-12Cr-16Ni. The samples were levitated in a magnetic field as a way of containerless processing. They were dropped onto a nucleation trigger and then into a quenching bath. This process was successful in producing quenched samples , but the layer of In-Ga wetting their surface showed problematic in the analysis of the samples. Data shows that double recalescence was observed in a few cases. SEM proved inconclusive and was not sensitive enough to detect the small chemical variations expected in the dendrites. Also, across the entirety of the sample there was no significant partitioning of Cr or Ni. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2001.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 41).

Exploring strengthening mechanisms for Class C and Class F fly ash in load bearing floor tile applications

Tue, 01 Jan 2013 00:00:00 GMT

Exploring strengthening mechanisms for Class C and Class F fly ash in load bearing floor tile applications Schein, Jaclyn Approximately 62.8 trillion kJ are consumed annually worldwide in the manufacturing process of traditional clay tiles. With this in mind, the goal of this project was to develop an eco-friendly alternative to clay tiles that maintain the ASTM building code standards. Through experimentation, a fly ash tile was produced that consumes 99% less energy in the manufacturing process than commercial clay tiles. The final product is a fly ash tile composed of two classes of fly ash, water, and several additives to strengthen the material. Standard ASTM tests were conducted. This fly ash tile is an energy efficient clay-tile alternative that excels in many mechanical properties. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2013.; "June 2013." Cataloged from PDF version of thesis.; Includes bibliographical references (pages 36-37).

Effects of silica nanoparticle surface treatment and average diameter on the physical and mechanical properties of poly(dimethylsiloxane)-silica nanocomposites

Fri, 01 Jan 2010 00:00:00 GMT

Effects of silica nanoparticle surface treatment and average diameter on the physical and mechanical properties of poly(dimethylsiloxane)-silica nanocomposites Guha, Ingrid F The purpose of this thesis was to quantify the effects of silica nanoparticle surface treatments and average silica nanoparticle diameter on various macroscopic properties of poly(dimethylsiloxane)-silica nanocomposites, specifically stiffness, wettability, and permeability to organic solvents. Poly(dimethylsiloxane)-silica nancomposites were prepared with constant amounts (4.8 wt%, 1.8 vol%) of fumed silica nanoparticles with varying surface treatments (hexamethyldisilazane and octamethylcyclotetrasiloxane) and varying particle diameter (7 and 12 nm). The Young's elastic modulus, mass increase due to dodecane absorption after 10 minutes, and advancing and receding water contact angles were measured for each nanocomposite. PDMS-silica nanocomposites containing untreated silica nanoparticles were found to have a higher Young's elastic modulus than nanocomposites containing hexamethyldisilazane-treated silica nanoparticles with the same diameter. However, nanocomposites containing identically sized silica nanoparticles with and without the octamethylcyclotetrasiloxane surface treatment had the same stiffness. The average nanocomposite stiffness increased slightly as the untreated silica nanoparticle diameter decreased from 12 nm to 7 nm. Varying the surface treatment or particle diameter of the filler did not significantly affect the level of dodecane absorption or the wettability of the nanocomposite. All nanocomposites showed approximately 20-23 wt% increase from dodecane absorption after 10 minutes of dodecane immersion. All nanocomposites exhibited average advancing contact angles around 115-120° and average receding contact angles around 85-90°. Nanocomposites were imaged using optical coherence tomography to examine particle dispersion. Potential differences in particle dispersion are discussed. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2010.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 35-37).

Natural variability in eastern tropical Pacific nitrous oxide emissions

Mon, 01 Jan 2018 00:00:00 GMT

Natural variability in eastern tropical Pacific nitrous oxide emissions Boles, Elisabeth L Nitrous oxide (N2O) is a powerful greenhouse gas and ozone depleting substance, but its natural sources remain poorly constrained. Marine emissions are likely much higher than IPCC estimates predict, due to unusually high emissions from the oxygen minimum zones (OMZs) in the eastern tropical Pacific and Arabian Sea that are not accounted for in assessments. Measurements of atmospheric concentrations from a selection of AGAGE stations around the Pacific Ocean were combined with back-trajectories calculated using the HYSPLIT4 atmospheric model, in order to study the relative importance of OMZs on Pacific N2O emissions. Spatial and temporal variability in nitrous oxide concentrations were analyzed in order to determine potential regions of higher emissions, as well as the impacts of ENSO on biogeochemistry in the OMZs. Air parcels that passed over the oxygen minimum zone in the Eastern Tropical South Pacific were found to have N2O concentrations as much as 0.5 ppb higher than average. Average concentrations over the OMZ were modulated by an additional ~0.2 ppb higher during La Niia events and ~0.2 ppb lower during El Niio periods, a deviation of the same order of magnitude as N2O's seasonal cycle. Comparisons with CFC-12 and SF6 suggested strong influences on nitrous oxide concentrations in the Southern Hemisphere from stratosphere-troposphere exchange, but little influence from inter-hemispheric transport. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 45-47).

Detecting the inclusion and exclusion of a neuronal XDP-associated microexon in situ

Mon, 01 Jan 2018 00:00:00 GMT

Detecting the inclusion and exclusion of a neuronal XDP-associated microexon in situ Ondik, Mercedes Maye X-linked dystonia parkinsonism (XDP), also known as torsion dystonia type 3 (DYT3), afflicts hundreds of individuals. Under an X-linked mode of inheritance, the DYT3 haplotype occurs in Filipino populations and is of the highest frequency in the Panay Islands of the Philippines. Recently, convincing evidence has shown the causative mutation to be an insertion of the repetitive sequence SINE-VNTR-Alus (SVA). This insertion is associated with misregulation of 3' end exons in the gene TBP-associated factor 1 (TAF1). TAF1, the largest of fourteen TAF proteins, incorporates into a TATA binding complex that promotes transcription by RNA polymerase II. In a collaborative effort, singleplex BaseScope" probes as well as antibodies have been produced to target two TAF1 isoforms, canonical TAF1, C-TAF1, and neuronal TAF1, N-TAF1, separately. N-TAF1 differs from C-TAF1 by the inclusion of a two amino acid microexon, 3' to the SVA insertion, known as 34'. Here, I show that N-TAF1 expression is confined to neurons and interneurons whereas C-TAF1 is widely expressed, particularly by astrocytes, interneurons, neurons, and cells present in other organs including the heart and liver in mouse. Additionally, the antibodies produced show promise for use in human tissue. These results support the hypothesis that C-TAF1 and N-TAF1 have canonical and neuron-specific functions, respectively, and misregulation of N-TAF1 is capable of causing neuronal degeneration. Ultimately these results set the foundation for the study of C-TAF1 and N-TAF1 functions and isoform misregulation in XDP diseased tissue. Furthermore, these probes and antibodies may serve as tools for the validation of XDP models, under development, in which forthcoming XDP therapies may be tested. Thesis: S.B. in Chemistry-Biology, Massachusetts Institute of Technology, Department of Brain and Cognitive Sciences, 2018.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged student-submitted from PDF version of thesis. "Submitted to the Department of Brian and Cognitive Sciences in supplement to the requirements for the degree of Bachelor of Science in Chemistry-Biology."; Includes bibliographical references (pages 52-54).

The empirical analysis of the red blood cell shape.

Sat, 01 Jan 1972 00:00:00 GMT

The empirical analysis of the red blood cell shape. Poulsen, Richard Stanley Massachusetts Institute of Technology. Dept. of Electrical Engineering. Thesis. 1972. B.S.; Includes bibliographical references.

Alternating conditional expectation (ACE) applied to classification and recommendation problems

Mon, 01 Jan 2018 00:00:00 GMT

Alternating conditional expectation (ACE) applied to classification and recommendation problems Kozynski Waserman, Fabián Ariel In this thesis, a geometric framework for describing relevant information in a collection of data is applied for the general problems of selecting informative features (dimension reduction) from high dimensional data. The framework can be used in an unsupervised manner, extracting universal features that can be used later for general classification of data. This framework is derived by applying local approximations on the space of probability distributions and a small perturbation approach. With this approach, different information theoretic results can be interpreted as linear algebra optimizations based on the norms of vectors in a linear space, which are in general, easier to carry out. Fundamentally, using known procedures such as Singular Value Decomposition (SVD) and Principal Component Analysis (PCA), dimension reduction for maximizing power can be achieved in a straight forward manner. Using the geometric framework, we relate calculation of SVD of a particular matrix related to a probabilistic channel to the application of Alternating Conditional Expectation (ACE) in the problem of optimal regression. The key takeaway of this method is that such problems can be studied in the space of distributions of the data and not the space of outcomes. This geometric framework allows to give an operational meaning to information metrics in the context of data analysis and feature selection. Additionally, it provides a method to obtain universal classification functions without knowledge of the important feature of the problem. This framework is the applied to the problem of data classification and analysis with satisfactory results. Thesis: Elec. E., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 37).

Fabricating Van der Waals heterostructures with air sensitive materials : a study of flake Bi₂Sr₂CaCu₂08₊x.

Mon, 01 Jan 2018 00:00:00 GMT

Fabricating Van der Waals heterostructures with air sensitive materials : a study of flake Bi₂Sr₂CaCu₂08₊x. Cohen, Liam Augustus Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, June 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages [96]-[97]).

Microneedle gastric retention for drug delivery

Mon, 01 Jan 2018 00:00:00 GMT

Microneedle gastric retention for drug delivery Dellal, David (David M.) Traditional drug delivery methods, such as injection and ingestion, are associated with many challenges, including patient needle-phobia and patient adherence to a medication regimen. Biologic molecules, in particular, must be injected due to degradation by enzymes in the GI tract. Previous scientists have developed a method with the potential to inject macromolecules in the GI tract using microneedles that can implant themselves in the stomach lining; however, they do not provide long-term drug delivery. To create a controlled release micro injection, I hypothesize that a hooked needle will latch onto the muscularis mucosae layer in the stomach and reside.upwards of a week to deliver drugs. A number of trials and simulations have been designed to test the efficacy of this retention mechanism. Coupled with work in the creation of new pharmaceutical formulations, these needles can be loaded with any drug to ensure uptake into the blood stream over the course of several days. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, June 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 25-28).

Effect of plastic strain on the corrosion of X65 pipeline steel

Mon, 01 Jan 2018 00:00:00 GMT

Effect of plastic strain on the corrosion of X65 pipeline steel Chitty, Chelsea Corrosion is an important mode of degradation and failure for iron alloys used in oil and gas pipelines. Pitting corrosion is a particular type of corrosion that is not well-understood and can play in important role in material failure. Research has shown that areas of increased plastic strain develop within pits which may promote crack initiation and material failure. This paper aims to analyze the impact of increased plastic strain on the general corrosion rate of X65 pipeline steel. Samples of X65 steel cold-rolled to 0%, 5%, 10%, 15% and 20% plastic deformation were tested using linear polarization methods in a 10% NaCl, CO2 saturated environment. It was found that there was no impact from the amount of plastic strain on the general corrosion rate of the X65 steel. Thesis: S.B., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, June 2018.; According to the thesis title-page, the thesis was submitted to the Department of Nuclear Science and Engineering. According to the MIT Registrar's Office, she got a degree from the Department of Civil and Environmental Engineering. Cataloged from PDF version of thesis.; Includes bibliographical references (pages [18]-[19]).

Methane and carbon dioxide cycling in soils of the Harvard Forest

Mon, 01 Jan 2018 00:00:00 GMT

Methane and carbon dioxide cycling in soils of the Harvard Forest Jaeger, Alexa Soil is Earth's largest terrestrial carbon pool (Oertel et al., 2016) and can act as a net source of greenhouse gases (GHG). However, if organic material accumulates in soils faster than it is converted to CO2 by cellular respiration, soil becomes a smaller GHG source and even has the potential to become a GHG sink. Not much is known about factors that drive soil to be a source or a sink of GHG. Soil temperature and moisture have both been shown to correlate with CH4 emissions and temperature has been shown to correlate with CO 2 emissions (Jacinthe et al., 2015). Currently these relationships are not well constrained, particularly in upland soils, which are soils found at elevations between 100 and 500 m (Carating et al., 2014). Soil from the Harvard Forest was collected and used in two in-lab flux experiments to constrain the effect that soil moisture has on i.) the rate of CH4 and CO2 production/consumption and ii.) the fraction of injected CH4 that is oxidized to CO2 by soil microbes. The first experiment involved injecting vials containing soil samples with CH4 , taking an initial measurement with a residual gas analyzer (RGA), incubating for three days, and taking final measurements using the RGA. The results of this experiment indicated that cellular respiration is an important carbon source in these soils, with more CO2 coming from cellular respiration than from the oxidation of CH4. The second experiment involved injecting vials containing soil samples with CH4 and 14CH4 as a tracer, incubating for six days, and analyzing CO2 from each sample using a scintillation counter. This experiment showed a weak trend indicating that increased soil moisture may result in decreased CH4 oxidation. Results showed that decays per minute from the samples were lower than in a control. These results indicated that not all CO 2 from each sample was successfully captured and analyzed using the methods here. So while the trend may hold true, it should be supported by reconducting the experiment using a more reliable means of CO2 capture. The unexpected results from both experiments indicated that there is still much to be learned about the reactions that occur in these soils and how to perfect laboratory methods to study them. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 18).

Identifying binary central stars of planetary nebulae with Kepler K2 campaign 11 photometric data

Mon, 01 Jan 2018 00:00:00 GMT

Identifying binary central stars of planetary nebulae with Kepler K2 campaign 11 photometric data Hurowitz, Jonathan L A large majority of planetary nebulae (PNe) are non-spherical, and many have complex structures; these are unlikely to be created trivially by a single central star. The Binary Hypothesis proposes that the complex morphologies of most non-spherical PNe are caused by interactions between their central stars and companions, with some unknown percentage in close binary systems. In this study, a software pipeline was developed to generate light curves for 140 PNe targets from the Kepler K2 campaign 11 field. Of these 140 targets, 29 appeared to show periodicity in their light curves, all of which had period under two weeks, for a close binary fraction of 21%; furthermore, 25 out of 29 (86%) detected periods were between two hours and five days. The size of this data set (140 PNe) is larger than any previous photometric search for close binary companions of PNe central stars, and the calculated short-period binary fraction is consistent with past photometric searches. These results support the Binary Hypothesis, which in turn helps explain the development of the varied and complex morphologies of PNe. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 24-26).

Investigation of the heterogeneous ice nucleation potential of sea spray aerosol

Mon, 01 Jan 2018 00:00:00 GMT

Investigation of the heterogeneous ice nucleation potential of sea spray aerosol Dove, Lilian A Bubble bursting at the ocean surface generates smaller film-burst particles and larger jet drop particles that differ in composition. The chemical composition of sea spray aerosols is an important parameter for the evaluation of their impact on the global climate system. This study investigates the role of particle chemistry on the heterogeneous ice nucleation potential of laboratory-generated sea spray aerosols. Cultures of Procholorococcus, a highly abundant marine phytoplankton species, were used as a model source of organic sea spray aerosols. Results show that smaller particles generated from the lysed Procholorococcus cultures were organically enriched and effectively activated as ice nucleating particles at warmer temperatures and lower supersaturations than larger particles. The role of chemical composition in the activation of the particles was studied by measuring the nucleation abilities of single component organic molecules that mimic proteins, lipids, and carbohydrates in Procholorococcus. Amylopectin, agarose, and aspartic acid exhibited nucleation behaviors similar to particles generated from Procholorococcus cultures. Therefore, carbohydrates and proteins with numerous and well-ordered hydrophilic functional groups may determine the ice nucleation potential of organic sea spray aerosols. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 19-23).

Development of a leaching procedure for isotopic study of metal/silicate partitioning experiments

Mon, 01 Jan 2018 00:00:00 GMT

Development of a leaching procedure for isotopic study of metal/silicate partitioning experiments Spanjers, Mary C The ratio of 238U/ 235U has long been assumed to be constant and equal to 137.88. However, recent research has found that uranium fractionation occurs in a variety of environments, especially reducing environments. Fractionation in metal/silicate systems could be a contributor to Earth's geodynamo heating and affect Pb-Pb geochronology. Sixteen experimental iron/silicate samples were separated magnetically into iron and silicate fractions. Each fraction was leached with 2.5 M HCl, 10 M HCl, 10 M HCl at a higher temperature, and HF and the uranium released in each step was measured by mass spectrometry. The depleted nature of the uranium used to create the samples precludes high-precision isotope fractionation assessments. However, the effectiveness of the leaching procedure was examined for potential use on future samples. The U release pattern in silicate fractions was not consistent between all of the samples, and major element concentration measurements will allow identification of the phase being digested in each step. The contamination from silicate and graphite in the metal fractions prevents uranium from being accurately measured. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 18-19).

Sublimative torques as the origin of bilobate comets

Mon, 01 Jan 2018 00:00:00 GMT

Sublimative torques as the origin of bilobate comets Safrit, Taylor K About 70 percent of observed cometary nuclei are bilobate (made up of two masses of material connected by a narrow neck). In contrast, only 10-20 percent of similarly-sized asteroids are contact binaries or bilobate, suggesting that some process unique to comets is responsible for the formation of bilobate shapes. We examine a new mechanism for creating bilobate nuclei in Jupiter-family comets (JFCs), in which sublimative torques acting on a comet during its migration through the Centaur region spin the nucleus up to disruption, after which it may reform in a bilobate shape. We find that JFCs smaller than approximately 100 kilometers in radius should experience enough torque from carbon monoxide and carbon dioxide sublimation over their dynamical evolution through the Centaur region to be restructured into bilobate shapes. This suggests that the observed bilobate distribution of comet shapes could be the result of cometary evolution, rather than a feature of primordial cometary reservoirs. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, June 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 23-26).

Evaluating Trends in Light-Duty Vehicle Technologies to Project Fuel Economy

Mon, 01 Jan 2018 00:00:00 GMT

Evaluating Trends in Light-Duty Vehicle Technologies to Project Fuel Economy Adcock, Christiane Predicting the fuel economy of future light-duty vehicles provides insight into the expected greenhouse gas emissions, oil consumption, and operating costs in the transportation sector. Fuel economy is difficult to directly predict, however, due to the large number of vehicle characteristics that influence fuel economy. These characteristics include curb weight, powertrain efficiency, tire properties, and aerodynamic properties. In addition, the characteristics vary by powertrain technology and vehicle class. This study evaluates past trends and literature projections for each attribute. It then projects fuel economy for three powertrain technologies and eight vehicle classes using current values, past trends, and literature projections for the vehicle characteristics and the Environmental Protection Agency's drive cycles. Fuel economy for internal combustion engine vehicles (ICEVs), hybrid electric vehicles (HEVs), and battery electric vehicles (BEVs) are projected to increase at rates similar to past years. At these rates, average HEVs and BEVs will significantly exceed Corporate Average Fuel Economy standards for 2021 and 2025, and ICEVs will fall significantly short of these standards. This analysis provides an easily adaptable framework to project fuel economy that accounts for the large number of contributing vehicle characteristics. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 39-40).

New buildings for the New England Peabody Home for Crippled Children : Oak Hill, Newton, Massachusetts

Fri, 01 Jan 1954 00:00:00 GMT

New buildings for the New England Peabody Home for Crippled Children : Oak Hill, Newton, Massachusetts Limon, Sylvan Thesis (B. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1954.; MIT copy bound with: A campus senior high school for Middletown, Connecticut / Jean Eleanor Fisch [1954] Accompanying drawings held by MIT Museum.; Includes bibliographical references (leaves 44-45).

Automated mask aligner for multilevel mask exposures

Fri, 01 Jan 1988 00:00:00 GMT

Automated mask aligner for multilevel mask exposures Owens, Anthony L. (Anthony LeRoy) Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1988.; Includes bibliographical references.

Imaging of residual limbs using motion processing with IMUs

Sun, 01 Jan 2017 00:00:00 GMT

Imaging of residual limbs using motion processing with IMUs Steinmeyer, Rebecca Hope Accurate imaging of residual limbs is necessary for the design of well-fitting sockets for prosthesis wearers. Unfortunately, current methods of acquiring residual limb geometry are often expensive and inaccessible. A measurement method is proposed using coordinated IMUs to achieve residual limb imaging through motion processing. The IMUs are fixed to an object which traces the surface of the residual limb. Trajectories are calculated for each IMU, and a correction method is applied using all IMUs fixed to the instrument surface to mitigate measurement drift. The IMU trajectories are then used to generate a triangulated geometry to digitally represent the residual limb. This method was simulated to guide instrument design and provide insight on performance and measurement process. The eventual goal is a glove with IMUs at the fingertips which may be used by an untrained individual, who may simply wear the glove and lightly survey the surface of the residual limb with their hand to produce data which will then be used to generate a digital limb geometry. Using the results of the simulation, a design is proposed for the glove. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 82-83).

Transit timing variations of the exoplanet K2-25b

Sun, 01 Jan 2017 00:00:00 GMT

Transit timing variations of the exoplanet K2-25b Nisley, Ishara Transit light curves of the exoplanet K2-25b were studied to examine the possibility of transit timing variations (TTVs) in the system, which could imply the presence of a perturbing planet. Observations of K2-25b transits were taken using 14-inch and 24-inch telescopes at Wallace Astrophysical Observatory. Two transit light curves were fit using an MCMC implementation to find the orbital period, planetary radius, and semi-major axis. A new period calculation yielded an orbital period of 3.48457 +/-0.00004, consistent with the period of 3.484552 +0.000044/-0.000036 from Mann et al. 2016. No significant variations were found in the midtimes of the new transit observations when comparing them to the midtime originally published in Mann et al. 2016. Future observations will require smaller uncertainties to meaningfully constrain the mass and period of potential perturbing planets. Signal-to-noise ratio calculations showed that telescopes over approximately 2.2 meters in diameter have better potential to detect small TTVs. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2017.; Cataloged from PDF version of thesis. "May 16, 2017." "This thesis was submitted to the Institute Archives without all the required signatures"--Disclaimer Notice page.; Includes bibliographical references (page 53).

Distribution of olivine and pyroxene in S-type asteroids throughout the inner main belt

Tue, 01 Jan 2008 00:00:00 GMT

Distribution of olivine and pyroxene in S-type asteroids throughout the inner main belt Storm, Shaye Perry The mineralogical composition of asteroids can be constrained using visible and near-infrared (VNIR) spectroscopy. The most prominent spectral features observed over this wavelength range are due to olivine and pyroxene, the two most abundant minerals in both chondritic and achondritic meteorites. The observed ratio of these two minerals is highly dependent on the amount of heating that an asteroid has undergone. The 1-micron band center wavelength and the band area ratio (BAR) between the 2- and 1-micron bands reveal relative abundances of olivine and/or pyroxene on an asteroid surface (Gaffey, 1993). A large sample of S-, A-, V-, and R-type asteroid spectra was collected over the visible and near-IR wavelengths during the second phase of the Small Main-belt Asteroid Spectroscopic Survey (Bus and Binzel, 2002) and using the low-resolution SpeX spectrograph (Rayner, 2003) at NASA's Infrared Telescope Facility (IRTF). Here we present a methodology for calculating the location of the 1-micron band center wavelength and BAR with appropriate 1- sigma uncertainties. This method was used to characterize 188 S-type asteroids throughout the inner main belt. We will also present the distribution of olivine / pyroxene throughout the main belt by measuring how the S-type mineralogy varies with heliocentric distance. This will provide a better understanding of both the thermal processing across the main belt and subsequent mixing of asteroids through collisional and dynamical processes. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2008.; Cataloged from PDF version of thesis. "May 5, 2008." "This thesis was submitted to the Institute Archives without all the required signatures"--Disclaimer Notice page.; Includes bibliographical references (page 33).

Low rare earth element concentration impact glass from the K/T Boundary at Beloc

Sat, 01 Jan 2011 00:00:00 GMT

Low rare earth element concentration impact glass from the K/T Boundary at Beloc Fantone, Dennis W This paper seeks to describe an impact glass from the K/T boundary layer at Beloc that is depleted in rare earth elements (REE) relative to continental crust. It is widely agreed that a large bolide struck the Yucatan Peninsula roughly 65 Ma spreading a worldwide iridium anomaly. However, there is only one case of a piece of the impactor being found (Kyte et al., 1995). Impact glass from the K/T boundary at Beloc, Haiti has been widely researched with several types of glass documented. So far, all of the documented glass exhibits a crustal REE compositional pattern. In this study, REE composition from two glass types from the same K/T boundary layer sample are examined using a laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS). One glass type exhibits crustal REE composition which is enriched normalized to chondrite. The other glass type, however, displays a meteoritic REE composition signature. REE patterns for this glass are nearly flat when plotted normalized to chondrite with an average La/Sm ratio of 1.51 compared to 2.69 for crustal glass. Major element data were obtained through electron microprobe analysis and displays a composition that differs from one glass type to the other. Results suggest chondritic parent material from the Chicxulub impactor. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, February 2011.; Cataloged from PDF version of thesis. "December 20, 2010." "This thesis was submitted to the Institute Archives without all the required signatures"--Disclaimer Notice page.; Includes bibliographical references (pages 33-34).

Analyzing the effects of different types of vegetation on evapotranspiration in Big Cypress National Preserve, FL

Tue, 01 Jan 2008 00:00:00 GMT

Analyzing the effects of different types of vegetation on evapotranspiration in Big Cypress National Preserve, FL Brown, Allison R Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2008.; Cataloged from PDF version of thesis. "Appendix B section - Variable Scatter Plots - contains pages with binder punch holes resulting in deleted text"--Disclaimer Notice page.

A 3-D tomographic survey of compound chondrules in two carbonaceous chondrites : Acfer 139 and Renazzo

Sat, 01 Jan 2005 00:00:00 GMT

A 3-D tomographic survey of compound chondrules in two carbonaceous chondrites : Acfer 139 and Renazzo Hylton, Shavonne Nyoka, 1983- Compound chondrules (CCs) are two or more chondrules fused or mechanically joined together. Studies of compound chondrules have been conducted in order to understand the chondrule formation process, including the environment and precursor materials. Chondrule formation is still not currently understood and much doubt still remains as to whether the chondrule formation process is nebular and/or planetary However, our evidence suggests that a primary and secondary process are responsible for CCs: (1) semi-molten collisions among individual (I) chondrules (Gooding and Keil, 1981) and (2) Parent-body impacts that cause jostling, fracturing and compaction (Wasson et al., 1995). By understanding chondrule collisions and impacts we can gain greater knowledge into what was happening during early solar system formation, including mean interparticle distances and velocities (Gooding and Keil, 1981). This thesis introduces x-ray tomography as a new method of measuring and surveying CCs; and explores the advantages and limitations of this method. A 3-D tomographic study of two CR carbonaceous meteorites, Acfer139 and Renazzo, reveals a higher frequency of compound chondrules in CR chondrites than in ordinary chondrites. Previous two-dimensional studies of compound chondrules are reexamined and two new categories, touching and aggregate compounds, are also introduced. Our reexamination suggests a 9.6% frequency of compound chondrules (excluding the new categories), twice more than the value of 4% found by Gooding and Keil (1981) and almost 4 times the value of 2.4% found by Wasson et al. (1995) in their studies of ordinary chondrites. The implications of a higher compound chondrule frequency on chondrule formation are also examined. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2005.; Cataloged from PDF version of thesis. "May 2005." "This thesis was submitted to the Institute Archives without all the required signatures."--Disclaimer Notice page.; Includes bibliographical references (pages 19-[21]).

Effects of space weathering on the Trojan asteroids

Tue, 01 Jan 2002 00:00:00 GMT

Effects of space weathering on the Trojan asteroids Deet, April A. (April Anne) Trojan asteroids orbit at Jupiter's L4 and L5 points. They are included in the D-class of asteroids because of their steep spectral slope. According to spectra of other asteroid classes, the larger the diameter is of a D-class asteroid, the redder the asteroid should be in the visible spectrum. We examined a total of fifteen asteroids, five (from the SMASS 1 data set) were small, and ten (newly collected data) were large. The actual results did not match our expected results, most likely due to the large error bars and the small data set. Space weathering may affect Trojans in the same way as it does other asteroid classes. To know with certainty, further investigation is needed. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2002.; Cataloged from PDF version of thesis. "The pagination in this thesis reflects how it was delivered to the Institute Archives and Special Collections. Thesis was submitted to the Institute Archives without all the required signatures"--Disclaimer Notice page.; Includes bibliographical references (page 40).

Photoluminescence and cathodoluminescence of undoped and cerium doped YAG single crystals

Fri, 01 Jan 1982 00:00:00 GMT

Photoluminescence and cathodoluminescence of undoped and cerium doped YAG single crystals Wong, Chon Meng Thesis (Elec.E)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.; Bibliography: leaves 172-176.

Using surface topography to re-analyze gradients in mussel byssal threads

Thu, 01 Jan 2015 00:00:00 GMT

Using surface topography to re-analyze gradients in mussel byssal threads Ryan, Emmie A Thin film instabilities have been heavily utilized in recent years in the fields of thin film production, biology and nano-fabrication. The creation of specific wrinkling and buckling patterns has been used as both a characterization and control technique. This project aims to apply the analysis of thin film wrinkling patterns to characterize the mechanical gradient in the collagenous core fiber of mussel byssal threads. Mussel byssal threads have a natural, stiff, thin outer coating that is chemically and mechanically distinct from the softer collagenous core making them a prime subject for wrinkling analysis. Past work in the area has focused on full thread strain recovery dynamics and biochemical analysis of the collagenous and coating components in an attempt to understand the physical characteristics of the mussel byssal threads. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2015.; "June 2015." Cataloged from PDF version of thesis.; Includes bibliographical references (pages 28-29).

Computation of the stresses in a parabolic arch rib and partial design of the bridge

Sat, 01 Jan 1910 00:00:00 GMT

Computation of the stresses in a parabolic arch rib and partial design of the bridge Navarro, M. A Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1910.

The effect of quick freezing on the bacteria in food products

Wed, 01 Jan 1930 00:00:00 GMT

The effect of quick freezing on the bacteria in food products Abare, Lawrence Parker Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Biology and Public Health, 1930.; Includes bibliographical references (leaves 67-68).

Characteristics of the house as determined by space-use, and its application to storage

Fri, 01 Jan 1943 00:00:00 GMT

Characteristics of the house as determined by space-use, and its application to storage Netsch, Walter Thesis (B.Arch)--Massachusetts Institute of Technology, Dept. of Architecture, 1943.; MIT copy bound with: An abattoir and meat packing plant in Baghdad, Iraq / Yusuf Meer. 1943.

Study of population sampling procedures and development of proportionate-stratified area random sample within Cambridge, Massachusetts

Fri, 01 Jan 1960 00:00:00 GMT

Study of population sampling procedures and development of proportionate-stratified area random sample within Cambridge, Massachusetts Coady, Edmond Patrick Thesis (B.S.)--Massachusetts Institute of Technology, School of Industrial Management, 1960.; MIT copy bound with: Approximating the point binomial with the Gram-Charlier type B series / by David Aaker, David Butterfield [1960]; Includes bibliographical references (leaves 84-85).

A comparision of the effects of Harvard and MIT on attitudes of technically oriented students

Fri, 01 Jan 1960 00:00:00 GMT

A comparision of the effects of Harvard and MIT on attitudes of technically oriented students Christensen, Duane Lee Thesis (B.S.)--Massachusetts Institute of Technology, School of Industrial Management, 1960.; MIT copy bound with: Approximating the point binomial with the Gram-Charlier type B series / by David Aaker, David Butterfield [1960]

Steps towards automatic scheduling of production at the Boston Naval Shipyard

Fri, 01 Jan 1960 00:00:00 GMT

Steps towards automatic scheduling of production at the Boston Naval Shipyard Buncher, C. Ralph (Charles Ralph), 1938- Thesis (B.S.)--Massachusetts Institute of Technology, School of Industrial Management, 1960.; MIT copy bound with: Approximating the point binomial with the Gram-Charlier type B series / by David Aaker, David Butterfield [1960]

Dynamic changes in the retail appliance and television market

Fri, 01 Jan 1960 00:00:00 GMT

Dynamic changes in the retail appliance and television market Bloom, Alan S. (Alan Stuart) Thesis (B.S.)--Massachusetts Institute of Technology, School of Industrial Management, 1960.; MIT copy bound with: Approximating the point binomial with the Gram-Charlier type B series / by David Aaker, David Butterfield [1960]; Includes bibliographical references (leaf 44).

Consumer preference within a wide range of fragrances by Lee Jay Alter.

Fri, 01 Jan 1960 00:00:00 GMT

Consumer preference within a wide range of fragrances by Lee Jay Alter. Alter, Lee Jay Thesis (B.S.)--Massachusetts Institute of Technology, School of Industrial Management, 1960.; MIT copy bound with: Approximating the point binomial with the Gram-Charlier type B series / by David Aaker, David Butterfield [1960]; Includes bibliographical references.

An addition to the Albright Art Gallery, Buffalo, N.Y.

Fri, 01 Jan 1960 00:00:00 GMT

An addition to the Albright Art Gallery, Buffalo, N.Y. Dattner, Richard, 1937- Thesis (B. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1960.; MIT copy bound with: A medium-security prison for Framingham, Massachusetts / George Adler [1960] Accompanying drawings held by MIT Museum.; Includes bibliographical references (leaf 33).

A magnetic accelerator

Tue, 01 Jan 1957 00:00:00 GMT

A magnetic accelerator Rushforth, William K. (William Kurth) Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Electrical Engineering, 1957.; MIT copy bound with: Fringe effects in a magnetohydrodynamic field / Benjamin Kornbluth. 1957.

Entrainment of solids from fluidized beds

Thu, 01 Jan 1953 00:00:00 GMT

Entrainment of solids from fluidized beds Ing, S. W. (Samuel W.) Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Chemical Engineering, 1953.; MIT copy bound with: The effect of sodium methyl siliconate on air dried bricks / Francis M. Glazier, Jr. 1953.; Bibliography: leaf 34.

An intercity bus terminal for Boston.

Wed, 01 Jan 1964 00:00:00 GMT

An intercity bus terminal for Boston. Heller, Jeffrey David Massachusetts Institute of Technology. Dept. of Architecture. Thesis. 1964. B.Arch.; Accompanying drawings held by MIT Museum. MIT Institute Archives and Special Collections copy bound with: Boorn, John P. A private day school from the Princeton community. (1964).

The effect of temperature on the electrical properties of standard cables

Fri, 01 Jan 1909 00:00:00 GMT

The effect of temperature on the electrical properties of standard cables Doane, R. E; Chase, P. H Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering, 1909.; Includes bibliographical references (leaf 87).

Investigation of air propellers

Mon, 01 Jan 1912 00:00:00 GMT

Investigation of air propellers Caldwell, Frank Walker; Lehmann, Hans Frank Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1912

A study of the methods of constructing foundations for high office buildings in Boston, Massachusetts

Wed, 01 Jan 1930 00:00:00 GMT

A study of the methods of constructing foundations for high office buildings in Boston, Massachusetts Guertin, Joseph David Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1930.; MICROFICHE COPY AVAILABLE IN ENGINEERING.

A neighborhood branch for the New England Museum of Natural History

Sat, 01 Jan 1944 00:00:00 GMT

A neighborhood branch for the New England Museum of Natural History Adams, Katherine B. (Katherine Brinkley) Thesis (B. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1944.; MIT copy bound with: A hydroelectric plant / by Richard W. Barry [1944] -- A newspaper publishing plant / Rosemary Burghoff [1944] -- A restaurant for the Massachusetts Institute of Technology / Abraham J. Goldberg [1944] -- Accompanying drawings held by MIT Museum.; Includes bibliographical references (leaves [32]-[34]).

Applying work simplification to the restaurant industry

Fri, 01 Jan 1960 00:00:00 GMT

Applying work simplification to the restaurant industry Baldwin, Bruce Wood Thesis (B.S.)--Massachusetts Institute of Technology, School of Industrial Management, 1960.; MIT copy bound with: Approximating the point binomial with the Gram-Charlier type B series / by David Aaker, David Butterfield [1960]; Includes bibliographical references.

Approximating the point binomial with the Gram-Charlier type B series

Fri, 01 Jan 1960 00:00:00 GMT

Approximating the point binomial with the Gram-Charlier type B series Aaker, David A; Butterfield, David Thesis (B.S.)--Massachusetts Institute of Technology, School of Industrial Management, 1960.; MIT copy bound with: Consumer preference within a wide range of fragrances / by Lee Jay Alter [1960] -- Applying work simplification to the restaurant industry / by Bruce Wood Baldwin [1969] -- Dynamic changes in the retail appliance and television market / by Alan S. Bloom [1960] -- Steps towards automatic scheduling of production at the Boston Naval Shipyard / by Charles Ralph Buncher [1960] -- A comparision of the effects of Harvard and MIT on attitudes of technically oriented students / by Duane Lee Christensen [1960] -- Study of population sampling procedures and development of proportionate-stratified area random sample within Cambridge, Massachusetts / by Edmond Patrick Coady, Jr. [1960]; Includes bibliographical references (leaf 11).

An experimental investigation of the flutter characteristics of low density wings

Wed, 01 Jan 1958 00:00:00 GMT

An experimental investigation of the flutter characteristics of low density wings Deyst, John J. (John Jacob) Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Aeronautical Engineering, 1958.; MIT copy bound with: An application of beryllium in the designing and testing of a high supersonic flutter model / John W. Brice, Jr. 1958.; Includes bibliographical references (leaf 17).

A six story apartment house

Wed, 01 Jan 1941 00:00:00 GMT

A six story apartment house Polivnick, Norton Thesis (B.Arch)--Massachusetts Institute of Technology, Dept. of Architecture, 1941.; MIT copy bound with: Cooperative farming and the independent home / Myron Dean Phillips. 1941. Accompanying drawings held by MIT Museum.; Includes bibliographical references (leaves [30]-[31]).

A quantitative study of some predetermined elemental time standard systems

Fri, 01 Jan 1960 00:00:00 GMT

A quantitative study of some predetermined elemental time standard systems Monahan, Richard E. (Richard Edward) Thesis (B.S.)--Massachusetts Institute of Technology, School of Industrial Management, 1960.; MIT copy bound with: The relative retention by the public of cartoon versus live, factual television advertising / by Arthur David Krulik [1960]; Includes bibliographical references (leaves [22]-[23]).

The relationship between Centaur activity and ring formation

Mon, 01 Jan 2018 00:00:00 GMT

The relationship between Centaur activity and ring formation Tigges, Sophia E Introduction: Centaurs are small bodies whose orbits lie between those of Jupiter and Neptune (Gehrels, 1999). They are thought to be transition objects that originate in the Kuiper belt and occupy the cis-Neptunian region before potentially becoming Jupiter-family or other short-period comets (Dones, Levison, & Duncan, 1996). Their short dynamical lifetimes are on the order of 106 years (Horner, Evans, & Bailey, 2004) due to their unstable, planet-crossing orbits (Horner, Evans, Bailey, & Asher, 2003). Some Centaurs have been observed to be active, and the bodies in the population of active Centaurs have perihelion distances that are statistically smaller than the median perihelion distance for all Centaurs, suggesting that Centaur activity is thermal in nature (Jewitt, 2009). Centaur activity may be observed through changes in the brightness of an object such as those exhibited by the Centaur Chiron (Parker et al., 1997). The presence of a coma around a Centaur may also provide evidence of activity, and dust comae have been detected around several bodies including Chiron (Meech & Belton, 1989; Luu & Jewitt, 1990) and Echeclus (Choi, Weissman, & Polishook, 2006). In addition to comae, other structures have been observed around Centaurs, such as the ring system that was discovered around Chariklo during a stellar occultation (Braga-Ribas et al., 2014). A symmetric feature was observed around Chiron during an occultation (Ruprecht et al., 2015), and some interpret this feature to be possible ring material (Ortiz et al., 2015). Similarly, the trans-Neptunian dwarf planet Haumea was revealed to have a ring during a stellar occultation (Ortiz et al., 2017). The collisional spreading time of Chariklo's rings was calculated to be on the order of 101 years, which is short in comparison to the estimated Centaur lifetime of approximately 106 years (Pan & Wu, 2016), yet Centaur rings are still observed despite this contradiction. Shepherd satellites may serve to increase the lifetime of a Centaur's rings (Pan & Wu, 2016) and maintain distinct ring edges such as those observed in Chariklo's ring system (Charnoz, Canup, Crida, Dones, 2017). Moreover, Centaur activity could supply material to an already present ring system, thus prolonging its lifetime. This study explores the potential connection between Centaur activity and Centaur ring systems by using the N-body integrator REBOUND to model outburst particle interactions and distributions. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 22-25).

Exploration vs. exploitation in coupon personalization

Mon, 01 Jan 2018 00:00:00 GMT

Exploration vs. exploitation in coupon personalization Atwi, Aliaa Personalized offers aim to maximize profit by taking into account customer preferences inferred from past purchase behavior. For large retailers with extensive product offerings, learning customer preferences can be challenging due to relatively short purchase histories of most customers. To alleviate the dearth of data, we propose exploiting similarities among products and among customers to reduce problem dimensions. We also propose that retailers use personalized offers not only to maximize expected profit, but to actively learn their customers' preferences. An offer that does not maximize expected profit given current information may still provide valuable insights about customer preferences. This information enables more profitable coupon allocation and higher profits in the long run. In this thesis we 1) derive approximate inference algorithms to learn customer preferences from purchase data in real time, 2) formulate the retailers' offer allocation problem as a multi armed bandit and explore solution strategies. Thesis: Elec. E. in Computer Science, Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 51-52).

Generator-level acceptance for the measurement of the inclusive cross section of W-boson and Z-boson production in pp collisions at [square root of] s = 5 TeV with the CMS detector at the LHC

Mon, 01 Jan 2018 00:00:00 GMT

Generator-level acceptance for the measurement of the inclusive cross section of W-boson and Z-boson production in pp collisions at [square root of] s = 5 TeV with the CMS detector at the LHC Andriatis, Alexander The inclusive cross section of vector boson production in proton-proton collisions is one of the key measurements for constraining the Standard Model and an important part of the physics program at the LHC. Measurement of the inclusive cross section requires calculating the detector acceptance of decay products. The acceptance of the CMS detector of leptonic decays of W and Z bosons produced in pp colisions at [square root of]s = 5 TeV is calculated using Monte Carlo event simulation. Statistical and systematic uncertainties on the acceptance measurement from PDF and a, uncertainty and higher-order correction are reported. The use of the calculated acceptance in combination with measurements of detector efficiency, luminosity, and particle counting to determine the inclusive cross section is outlined. A total integrated luminosity of 331.64 pb-1 from 2015 and 2017 CMS data at [square root of]s = 5 TeV is available for the calculation of the inclusive cross section. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2018.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 39-42).

An investigation of the aerodynamic characteristics of rotating wind-driven airfoils

Thu, 01 Jan 1925 00:00:00 GMT

An investigation of the aerodynamic characteristics of rotating wind-driven airfoils Hosch, John L; Weihmiller, H. E Thesis (B.S.)-- Massachusetts Institute of Technology, Dept. of General Engineering, 1925.

X-ray determination of the solid solubility of silver in cadmium

Fri, 01 Jan 1937 00:00:00 GMT

X-ray determination of the solid solubility of silver in cadmium Cuthbert, Stuart Verne Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mining and Metallurgy, 1937.; MIT copy bound with: Investigation of E.G. Herbert's magnetic hardening of metals / by Farmer L. Current [1937]; Includes bibliographical references (leaf 37).

The phase diagram of the sodium bromide-water system by the thermal analysis method

Sun, 01 Jan 1950 00:00:00 GMT

The phase diagram of the sodium bromide-water system by the thermal analysis method Hebert, Richard Armand, 1929- Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Chemistry, 1950.; MIT copy bound with: Indicators for work with nonpolar solvents / Paul H. Egan. 1950.; Bibliography: leaves 50-51.

An automatic news article editor

Thu, 01 Jan 1987 00:00:00 GMT

An automatic news article editor Côté, Robert G. (Robert Gerard) Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1987.; Bibliography: leaf 50.

Trade and the environment : the political economy of CO₂ emission leakage with analysis of the steel and oil sands industries

Thu, 01 Jan 2009 00:00:00 GMT

Trade and the environment : the political economy of CO₂ emission leakage with analysis of the steel and oil sands industries Chan, Gabriel Angelo Sherak Introduction: In 2007, scientists and governmental officials from around the world contributed to the United Nations-authorized Intergovernmental Panel on Climate Change's (IPCC) Fourth Assessment Report. Through peer-reviewed scientific research and governmental review, the IPCC came to the conclusion that "warming of the climate system is unequivocal," and that "most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations." The IPCC Fourth Assessment states that humans have "more likely than not" contributed to the phenomena of more frequent "warm spells/heat waves," larger "area[s] affected by droughts," more "intense tropical cyclones.. .and heavy precipitation events," and "extreme high sea level[s]." Citing "high agreement" and "much evidence," the IPCC states that "with current climate change mitigation policies and related sustainable development practices, global GHG [greenhouse gas] emissions will continue to grow over the next few decades." (Intergovernmental Panel on Climate Change, 2007) Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2009.; Thesis: S.B., Massachusetts Institute of Technology, Department of Political Science, 2009.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 113-116).

Characterizing the evolution of porosity and permeability in porous media undergoing pressure solution creep.

Sun, 01 Jan 2012 00:00:00 GMT

Characterizing the evolution of porosity and permeability in porous media undergoing pressure solution creep. Swanberg, Cassandra This work looks at the change in pore-scale morphological properties such as porosity and permeability using modeled sphere packs. The effects of varying pressure, temperature, and stress upon these properties are evaluated in numerically derived sphere packs undergoing creep and elastic compaction processes. This thesis will utilize the abilities of the lattice Boltzmann method and the network model method to determine various morphological properties of these sets of packed spheres. The results from these two methods can be combined to further analyze the relationship between pore space morphology and fluid flow parameters in porous media that can be used to develop correlations to predict permeability based upon the physical structure of the pore space. S.B. Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences June 2012; Thesis: S.B. in Engineering, Massachusetts Institute of Technology, Department of Chemical Engineering, June 2012.; "May 18, 2012." Title page signed, "Cassandra Swanberg." Cataloged from PDF version of thesis.; Includes bibliographical references (pages 38-40).

Pre-eruptive conditions beneath Medicine Lake Volcano, California, during the Pleistocene epoch

Sat, 01 Jan 2000 00:00:00 GMT

Pre-eruptive conditions beneath Medicine Lake Volcano, California, during the Pleistocene epoch Hooper, Heather J. (Heather Julie), 1975- This investigation uses the variations in composition of lavas and mineralogical evidence to characterize the preeruptive conditions beneath Medicine Lake Volcano (MLV) during the Pleistocene epoch. Prior to this investigation, the Pleistocene lavas of MLV had not been extensively studied because detailed time relations among them were not known. Recent work by Donnelly-Nolan has provided a time framework for relating these lavas, and has afforded us the opportunity to perform this study. Whole rock analyses for major elements, trace elements, and rare earth elements were performed, as well as electron microprobe analyses of individual minerals in the lavas. These analyses indicate that the lavas were formed by the mixing of three components. The first component was formed by fractional crystallization of a high-H20 magma (water content of 3-4 wt%) which was emplaced in the shallow crust, at approximately 1 kbar of pressure and temperatures between 980-1300K. The emplacement and crystallization of the first component supplied the heat necessary to melt the granitic crust under MLV. The crustal melt that resulted formed the second component. The third component was a fresh input from the mantle, whose injection into the shallow crust mixed all three components together. The pre-eruptive environment of these lavas was more oxidizing than those of other MILV lavas, such as the Holocene-aged Glass Mountain rhyolite. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, June 2000.; "June 2000." Cataloged from PDF version of thesis.; Includes bibliographical references (page 31).

Simulation of X-ray phase imaging on integrated circuits

Sun, 01 Jan 2017 00:00:00 GMT

Simulation of X-ray phase imaging on integrated circuits Arthur, Kwabena (Kwabena K.) A study on the simulation of the X-Ray phase imaging on multi-layered integrated circuits (IC) is presented. Model IC's were created with random nanoscale features. First order Rytov approximation was then used in order to accurately and rapidly create diffraction images. This study lays the foundation for future use as a forward model in limited-angle tomography or other inverse problems approaches (e.g neural networks) to reconstruct IC layout from x-ray diffraction images. In particular, it is hoped that the simulation presented here can be used to train neural networks that will carry out the inverse problem in experimental situations. The results of the study show that the first Rytov method is promising for use in this application of IC reconstruction. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; DISCLAIMER NOTICE: The pagination in this thesis reflects how it was delivered to the Institute Archives and Special Collections. Massachusetts Institute of Technology. The images contained in this document are of the best quality available. Cataloged from PDF version of thesis.; Includes bibliographical references (page 12).

After treatment and turbocharger effects on emissions of a diesel engine

Sun, 01 Jan 2017 00:00:00 GMT

After treatment and turbocharger effects on emissions of a diesel engine Schmidt, Kristina (Kristina E.) An experimental study on the effects of after treatments and a turbocharger on emissions of a single cylinder diesel engine. The study measured the concentration of CO, CO2, HC, NO, NO2, and NOx. Tests on the engine were performed at different engine loads and engine speeds. The engine power ranged from 0 to 9 HP, and the engine speed ranged from 1500 to 3500 rpm. Emissions were characterized in terms of engine speed, engine power, and exhaust temperature. The results showed that the optimal strategy for emission reduction was to combine the Diesel Oxidation Catalyst and the Diesel Particulate Filter to form a Continuously Regenerating Trap. These after treatments would be combined with the use of a turbocharger and air capacitor to ensure that the back pressure doesn't take away too much power and increase fuel consumption. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; DISCLAIMER NOTICE: The pagination in this thesis reflects how it was delivered to the Institute Archives and Special Collections, Massachusetts Institute of Technology. Cataloged from PDF version of thesis.; Includes bibliographical references.

Telluridm-induced corrosion of structural alloys for nuclear applications in molten salts

Sun, 01 Jan 2017 00:00:00 GMT

Telluridm-induced corrosion of structural alloys for nuclear applications in molten salts Skowronski, Natasha (Natasha C.) The mechanism by which tellurium causes intergranular corrosion (IGC) of structural alloys in molten salt reactors is currently poorly understood. Limited corrosion testing has been performed on a few select alloys in simulated reactor conditions. In this thesis, the results of performing 50 h, 100 h, and 150 h corrosion tests on alloys Hastelloy N, Nickel-201, Incoloy 8ooH, and 316L Stainless Steel are presented. Upon inspection of the corroded surfaces of each alloy after its immersion in molten LiF-NaF-KF (FLiNaK) salt at 700 °C using scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS), a consistent corrosion rate could not be determined for any of the alloys, nor could confident identification of telluride compounds within the corrosion layer or grain boundaries of any alloy be made. However, the results did appear to confirm the importance of using a low oxygen environment and avoidance of galvanic corrosion during testing. Furthermore, preliminary results from EDS analysis of one alloy sample implied that, with improved count rates taken during the elemental identification process, tellurium may be more clearly revealed in the corrosion layers and grain boundaries of the alloys tested. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.; DISCLAIMER NOTICE: The pagination in this thesis reflects how it was delivered to the Institute Archives and Special Collections. Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 46-48).

Redesign of the platform-side actuation system for the Kendall Band interactive musical sculpture

Sun, 01 Jan 2017 00:00:00 GMT

Redesign of the platform-side actuation system for the Kendall Band interactive musical sculpture Heman-Ackah, Marian The Kendall Band is an interactive musical sculpture by Paul Matisse located within the MBTA's Kendall/MIT Train Station. The sculpture, installed in 1987, consists of three instruments, Kepler, Galileo, and two sets of bells known as Pythagoras, each operated by its own system of mechanisms and linkages, and "played" by passengers using handles located on each platform. The sculpture as a whole has ceased to function as a result of a series of mechanical failures. Repair needs outpaced the resources available to maintain the sculpture. The primary known failure points are located within the portion of the actuation system on the platform of the station. Several components within this current actuation system are prone to fracture and wear. A new actuation system has been designed with various features that serve to increase overall durability, including a kinematic coupling with a spring-loaded interface that decouples actuation above a torque threshold of 225 in-lbf. Additionally, the newly designed actuation system has been standardized across all three instruments to simplify maintenance of the sculpture by incorporating a modular plate that has connection points for each instrument. Preliminary load testing performed upon a simplified version of the coupling interface proved promising for the design, but further work is required to prepare the design for installation. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; DISCLAIMER NOTICE: The pagination in this thesis reflects how it was delivered to the Institute Archives and Special Collections, Massachusetts Institute of Technology. Cataloged from PDF version of thesis.; Includes bibliographical references (page 24).

Mercury vapor - binary cycle boiler versus high pressure units

Fri, 01 Jan 1932 00:00:00 GMT

Mercury vapor - binary cycle boiler versus high pressure units Jenkins, Thomas H; Powell, Edwin B Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1932.; MICROFICHE COPY AVAILABLE IN ENGINEERING.

Electrodeposition of aluminum from organic solutions

Sun, 01 Jan 1939 00:00:00 GMT

Electrodeposition of aluminum from organic solutions Sze, Morgan Chuan-yuan, 1917- Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1939.; MIT copy bound with: Vulcanization of rubber under stretch / Irving N. Smith. 1939.; Includes bibliographical references (leaves 31-32).

Using machine learning for hydrocarbon prospecting in Reconcavo Basin, Brazil

Fri, 01 Jan 2016 00:00:00 GMT

Using machine learning for hydrocarbon prospecting in Reconcavo Basin, Brazil Zhakiya, Elezhan Machine Learning techniques are being widely used in Social Sciences to find connections amongst various variables. Machine Learning connects features across different fields that do not seem to have known mathematical relationships with each other. In natural resource prospecting, machine learning can be applied to connect geochemical, geophysical, and geological variables. However, the biggest challenge in machine learning remains obtaining the data to train the ML algorithms. Here, we have applied machine learning on data extracted from maps via image processing. While the overall accuracy of prediction remains as low as 33% at this stage, we see places where the algorithm can be improved and the accuracy increased. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages [28]).

A machine-learning approach to aerosol classification for single-particle mass spectrometry

Sun, 01 Jan 2017 00:00:00 GMT

A machine-learning approach to aerosol classification for single-particle mass spectrometry Christopoulos, Costa (Costa D.) Compositional analysis of atmospheric and laboratory aerosols is often conducted via single-particle mass spectrometry (SPMS), an in situ and real-time analytical technique that produces mass spectra on a single particle basis. In this study, machine learning classification algorithms are created using a dataset of SPMS spectra to automatically differentiate particles on the basis of chemistry and size. While clustering methods have been used to group aerosols into broad categories based on similarity, these models do not incorporate known aerosols labels and are not explicitly formulated for classification. Furthermore, traditional methods often rely on a smaller set of well-known, important variables whereas the proposed method is more general and flexible, allowing researchers to automatically quantify and select important variables from any aerosol subset. In this work, machine learning algorithms build a predictive model from a training set in which the aerosol type associated with each mass spectrum is known. Several such classification models were created to differentiate aerosol types in four broad categories: fertile soils, mineral/metallic particles, biological, and all other aerosols using -40 common positive and negative spectral features. For this broad categorization, machine learning resulted in a classification accuracy of -93%. More complex models were developed to classify aerosols into specific categories which resulted in a classification accuracy of -87%. The trained model was then applied to a 'blind' mixture of aerosols with model agreement on the presence of secondary organic aerosol, coated and uncoated mineral dust and fertile soil. Additionally, the model is used to characterize an ambient atmospheric dataset collected from the free troposphere. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 21-26).

An investigation into the design of surface piercing super cavitating hydrofoils

Sun, 01 Jan 2017 00:00:00 GMT

An investigation into the design of surface piercing super cavitating hydrofoils Dutton, Timothy Spaulding The fluid-dynamic design of hydrofoils to support marine crafts at high speeds has received growing interest in recent years. Physics involved in the design of high-speed surface-piercing hydrofoils is complex involving three different fluid phases (air, water and vapor) and complex fluid dynamic mechanisms like unsteady cavitation and ventilation and their interaction. For speeds considerably higher than the incipient cavitation speed, the hydrofoil sections need to be adapted and design to exploit cavitation instead of avoiding it. This is particularly true for surface piercing hydrofoils that in addition to cavitation are affected by ventilation from the free surface. This thesis presents main results of an investigation into the relative formation of ventilation and cavitation regions of surface piercing super cavitating hydrofoils (SPSCHs), with special attention to the effects of cavitation number. A series of 3D multi-phase Reynold Averaged Navier-Stokes Equation (RANSE) simulations of varying cavitation number reveal the dependence of the ventilation and cavitation regions on the cavitation number, angle of attack, and distance from the free surface. The RANSE simulations are validated against an analytical estimate based on an appropriate lifting line method at near zero cavitation numbers, and against empirical results obtained through tow tank testing at higher cavitation numbers. The analytical and empirical validation bound the range of cavitation numbers considered in this study from [sigma]= 0.05 to [sigma]= 2.37. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 49-50).

Surface characteristics of near-earth objects

Wed, 01 Jan 2003 00:00:00 GMT

Surface characteristics of near-earth objects Hsia, Nancy P Asteroids are thought to be the source of all meteorites found on Earth. Numerous spectroscopic studies have been performed to try and link certain types of meteorites with certain classes of asteroids in space. However, these spectroscopic studies of meteorites and asteroids have often shown a discrepancy between the meteorite and asteroid spectra, with the asteroid spectra showing a higher red slope and less prominent absorption bands. This effect has been seen especially in the spectra of asteroids located in the main belt. Scientists now believe that space weathering processes, such as solar wind ion implantation and bombardment by micrometeorites, can affect the upper few millimeters of an asteroid's surface to produce the higher red slope and reduced absorption bands seen in spectra. However, asteroids in the near- Earth region, which are generally smaller than those found in the main belt, have not shown signs of space weathering as much as asteroids in the main belt. The purpose of this study was to investigate factors that might influence the appearance of near-Earth asteroid spectra, in particular the conditions at the time of observation. The two main observational conditions examined were the apparent magnitude of the object, or V-magnitude, and the angle between the Earth, object, and Sun, commonly called the Phase Angle. Running-box average plots and least-squares analysis was performed on a data set of 332 near-Earth asteroids to determine if any links could be made between the spectral characteristics and observational parameters. The most interesting finding of this study was a correlation in the SQ-complexes between the second spectral component, PC2', which indicates the presence or absence of an absorption band at 1 [mu]m, and the Phase Angle for the SQ-complex asteroids, suggesting that the observation angle affects the spectrum of an asteroid. One possible explanation may lie in the fact that the particle size of the asteroid surface must be much larger than the wavelength of the light to create the multiple scattering needed to reflect light in the direction of the Earth. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2003.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 32-33).

Direction of spin of Koronis family member (1289) Kutaïssi

Wed, 01 Jan 2003 00:00:00 GMT

Direction of spin of Koronis family member (1289) Kutaïssi Klesman, Alison J. (Alison June), 1981- Observations of lightcurve of Koronis family member asteroid (1289) Kutaïssi were taken in January, 2003, at MIT's Wallace Astrophysical Observatory. The goal of these observations included obtaining a precise rotation period and direction of rotation for the asteroid extracted from data obtained in two different filters. By combining the new data with data from previous epochs, a rotation rate and direction of spin were found; results give a period of 3.62424 ± 0.00001 hrs and the asteroid was found to be spinning retrograde to its orbital motion. The results obtained from this project will be useful in the future for determining a shape and pole solution for (1289) Kutaïssi. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2003.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 41).

The Mercurian magma ocean, first crust, and implications for planetary formation mechanisms

Fri, 01 Jan 2010 00:00:00 GMT

The Mercurian magma ocean, first crust, and implications for planetary formation mechanisms Brown, Stephanie Marie,Ph.D.Massachusetts Institute of Technology. The size of the Mercurian core and the low ferrous iron bearing silicate content of its crust offer constraints on formation models for the planet. Here we consider a bulk composition that allows endogenous formation of the planet's large core, and by processing the mantle through a magma ocean, would produce a low-iron crust. More Earth-like bulk compositions require silicate removal, perhaps by a giant impact, to create the planet's large core fraction. The earliest crusts expected in a giant impact scenario are discussed in comparison to the endogenous model. We find that the endogenous model can produce a large core with either a plagioclase flotation crust or a low-iron magmatic crust. For the giant impact model, in the absence of a plagioclase flotation crust, the impact may be constrained to occur within about 300,000 years of the planet's initial fractionating magma ocean, at which time the giant impact can remove most of the silicate iron oxide budget of the planet before gravitational overturn carries it into the deep planetary interior. Thus a specific bulk composition is required to make Mercury endogenously, but specific timing of events is required to make it exogenously through giant impact. Measurements taken by the MESSENGER mission, when compared to predictions given here, may help resolve Mercury's formation process. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, June 2010.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 29-33).

The impact of Arctic cloud water and ice on cloud radiative forcing during the Arctic Summer Cloud-Ocean Study in August 2008

Fri, 01 Jan 2010 00:00:00 GMT

The impact of Arctic cloud water and ice on cloud radiative forcing during the Arctic Summer Cloud-Ocean Study in August 2008 Maroon, Elizabeth A The Arctic atmosphere is especially sensitive to changes in climate forcing; however, Arctic processes and feedbacks are not understood well enough to accurately predict how the Arctic environment might change under anthropogenic forcing. Further study of the basic atmospheric processes is needed, especially due to uncertainties in modeling cloud feedbacks. August and September are the months when the Arctic sea surfaces begin to freeze; clouds play an important role in determining when this process begins. In this study, the radiative properties of Arctic stratocumulus are studied by comparing measurements for two days in August 2008 during the Arctic Surface Cloud Ocean Study (ASCOS) with simulations using the Rapid Radiative Transfer Model (RRTM). Cloud radiative forcing for both days is examined, and the modeled radiative fluxes were found to compare well to observations. Sensitivity studies are conducted on single and multi-level stratocumulus clouds to study their radiative interactions with each other. Cloud-top cooling in upper clouds is found to radiatively turn off cloud-top cooling in clouds below it. The RRTM and the surface radiative observations are used together to constrain estimates of liquid droplet radius; constraining these radii shows the sensitivity of shortwave cloud radiative forcing and the insensitivity of long wave cloud forcing to changes in drop size. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2010.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 49-52).

The contact relationship between an large orogenic ultramafic massif and its surrounding units: Beni Bousera northern Morocco

Thu, 01 Jan 2009 00:00:00 GMT

The contact relationship between an large orogenic ultramafic massif and its surrounding units: Beni Bousera northern Morocco Piasecki, Alison M Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2009.; Cataloged from PDF version of thesis. Original thesis missing page 1, the Abstract page.; Includes bibliographical references (page 32).; Introduction - The Beni Bousera ultramafic massif is an orogenic lherzolite in northern Morocco, and is part of a large series of ultramafic massifs (Chalouan and Michard, 2004). Like all orogenic lherzolite the method of emplacement into the upper crust is not well understood (Reuber et al., 1982). In this thesis, the Filali gneiss, Kinzingite gneisss, and leucocratic dikes were studied in order to find out their contact relationship with the ultramafic body. A detailed cross section was completed starting in the south, 2 kilometers from the contact, up to the contact. The detailed structures of the exposed gneiss along a transect towards the contact between the host gneiss and ultramafic was studied. Additionally, pressure and temperature estimates on three samples along the transect has been conducted.

High precision U/Pb geochronology on the Cenomanian Dakota Formation, Utah : implications for paleobotany and the transgression of the Western Interior Seaway preceding Oceanic Anoxic Event 2

Fri, 01 Jan 2010 00:00:00 GMT

High precision U/Pb geochronology on the Cenomanian Dakota Formation, Utah : implications for paleobotany and the transgression of the Western Interior Seaway preceding Oceanic Anoxic Event 2 Meyer, Laura (Laura B.) The Dakota Formation was deposited during the Cenomanian, a time when the Western Interior Seaway spanned much of North America. The Dakota Formation contains a rich record of plant and animal fossils. Key to understanding their importance, it is imperative to precisely place the Dakota Formation within the geological time scale. Volcanic ash samples interlayed with fossil bearing sandstones of the Dakota were collected from two localities in Westwater, and Henrieville, Utah. Samples were dated using isotope dilution thermal ionization mass spectrometry (ID-TIMS). The samples collected from the Westwater, Utah localities have a weighted mean 206Pb/238U date of 97.656±0.082 Ma, while the samples taken from Henrieville, Utah have weighted mean 206Pb/238U dates of 95.170 0.056 Ma and 94.941±0.032 Ma. Based on an analysis of stratigraphic, paleontological, and geochronological data, the Dakota Formation was then correlated across much of the Western Interior. These dates provide a base of the initiation of the transgression across Utah, and set a context for the CT boundary and OAE2 that follow. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2010.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 31-35).

A paleomagnetic study of the angrite Sahara 99555

Thu, 01 Jan 2009 00:00:00 GMT

A paleomagnetic study of the angrite Sahara 99555 Slotznick, Sarah Pearl Sahara 99555 (SAH 99555) is the oldest dated angrite sample, a rare type of meteorite, and is only ~2 Myr younger than the age of the solar system (1, 2). SAH 99555 shows no post-cooling brecciation or weathering from the parent body, and does not display signs of significant terrestrial weathering. Therefore, paleomagnetic experiments were conducted for the first time on SAH 99555 to discover if it contains a primary paleomagnetism and then to determine a paleointensity estimate and its ferromagnetic mineralogy. Our studies show that the primary ferromagnetic mineral in SAH 99555 is magnetite and there are also some accessory ferromagnetic minerals including titanomagnetite and hematite. The natural remanent magnetization (NRM) of SAH 99555 appears to have a low-coercivity component probably from a collector's hand magnet or the Earth's field as well as a high-coercivity component, similar to D'Orbigny, another angrite. The paleointensity measurements of the high-coercivity component of SAH 99555,5 agree with the paleointensity estimates made for other angrites (D'Orbigny and A-881371) by Weiss et al. (2008) (4). Therefore, it appears that SAH 99555 does record a primary paleofield from when it was on the angrite parent body, which would be the oldest known paleomagnetic record yet identified in a planetary rock. Further studies are suggested to verify these conclusions, which make SAH 99555 one more key data point in the understanding of the early solar system. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2009.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 25-30).

U-Pb geochronology of the Acasta Gneiss Complex in Northwest Canada

Thu, 01 Jan 2009 00:00:00 GMT

U-Pb geochronology of the Acasta Gneiss Complex in Northwest Canada Safipour, Roxana G The Acasta Gneiss Complex in Northwest Canada contains the oldest dated rocks in the world. The gneisses range in age from 4.03-3.6 Ga, as determined by U-Pb dating of zircons (Bowring and Williams 1999). U-Pb dating of xenocrystic cores in these zircons indicates a cryptic record of continental crust older than 4.0 Ga. In this study, zircons were selected and characterized from thirteen samples of Acasta Gneisses. Many of the zircons contain xenocrystic cores mantled by younger domains. U-Pb geochronological data were collected using laser ablation inductively coupled plasma mass spectrometery (LA-ICPMS). Twelve of the samples show evidence for two distinct crystallization events, one which formed the cores and another in which the mantle domain overgrew the cores. The oldest cores were dated at >4.0 Ga. This provides additional evidence for pre-4.0 Ga crust formation in the late Hadean. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2009.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 58-59).

Paleomagnetism conglomerate test on Archean conglomerate rock from Jack Hills, Australia

Sat, 01 Jan 2011 00:00:00 GMT

Paleomagnetism conglomerate test on Archean conglomerate rock from Jack Hills, Australia Bowens-Rubin, Rachel A paleomagnetism study known as a conglomerate test was run on an Archean sandstone conglomerate rock to determine if the sample contained a remnant magnetization from the time of its formation. Twenty-nine clasts from a thin section of the sample were thermally demagnetized up to a temperature of 395°C. The heating revealed two components of magnetization which were unblocked at low and mid temperatures, revealing a magnetic mineralogy of Pyrrhotite.Eight matrix samples were heated to a temperature of 650°C which revealed two components of magnetization at mid and high temperatures, providing evidence for a magnetic mineralogy of Hematite.The direction of measured magnetic moment of the clasts were statistically similar, indicating that the rock failed the conglomerate test and was remagnetized after the rock formed. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2011.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 59-60).

A global and tropical quasi-decadal oscillation of the atmosphere and Ocean

Sat, 01 Jan 2011 00:00:00 GMT

A global and tropical quasi-decadal oscillation of the atmosphere and Ocean Agard, John Vincent An oscillatory, quasi-periodic signal with a period of around 10 years was found in radiosonde- and satellite-measured datasets of lower stratospheric temperature. Power spectrum analysis and Fourier decomposition were used to characterize the temporal and vertical manifestations of the signal, while EOF analyses were used to analyze its spatial characteristics. The oscillation was found to be unrelated to the solar activity cycle, while it displayed coherence with similar oscillatory signals in ENSO, PDO and AMO indices, as well as with a quasi-decadal signal in SST data. Finally, the quasi-decadal signal in lower stratospheric temperature was found to have a small but measurable contribution to the signal of tropical cyclone potential intensity in the Atlantic MDR. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2011.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 72-75).

Developing proxy radar data with the aid of cloud-to-ground lightning for a nowcasting system

Thu, 01 Jan 2009 00:00:00 GMT

Developing proxy radar data with the aid of cloud-to-ground lightning for a nowcasting system Munsell, Erin B Air traffic managers need up to date nowcast information over the entire CONUS for efficient operations in the National Airspace System. In areas of degraded or no radar coverage, cloud-to-ground lightning (provided by the National Lightning Detection Network) can provide valuable information through the creation of proxy vertically integrated liquid (VIL) and echo tops (ET). To develop these lightning-VIL and lightning-ET relationships, analysis of the lightning and radar data was done in "climate zones" throughout the CONUS, due to the potential for different lightning behavior in different areas of the country. After a quantile analysis revealed differences in the data between zones, lightning-VIL. and lightning-ET relationships were developed using a probability matching method for a baseline relationship (all climate zones) and for each individual climate zone. The potential benefits of the inclusion of each zone were analyzed through a bootstrap testing of the proxy VIL and proxy ET models, and performance was assessed using a system of binary scoring. For a given lightning flash rate, VIL values in the Mid-Latitude Land West zone were considerably lower than in other zones. The Mid-Latitude Land West zone also showed a noticeable improvement in the performance of the proxy VIL model. For a given lightning flash rate, ET values in the Mid-Latitude Water zone were considerably lower than in other zones. The Mid-Latitude Water zone appeared to provide a statistical improvement in the proxy ET model, but because of a lack of data in this zone on the days chosen for model testing, this improvement was not noticeable in the overall performance of the proxy ET model and needs to be investigated further. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2009.; Cataloged from PDF version of thesis. Original thesis missing page 55.; Includes bibliographical references (pages 71-72).

Theoretical detection limits and error reduction for radial velocity observations of an Earth-like exoplanet

Thu, 01 Jan 2009 00:00:00 GMT

Theoretical detection limits and error reduction for radial velocity observations of an Earth-like exoplanet Moberger, Allison L The intent of this project was to determine the relationship between the number of radial velocity observations of an Earth-twin exoplanet and the error in the mass calculated from the detected signal. If the planet's period is known through prior transit observations, the mass may be measured by radial velocity more accurately; this project tested and measured the conditions for this error reduction. Simulated sets of radial velocity data taken by HARPS (accurate to 1 m/s) for an Earth-mass planet in a circular, edge-on, 1 AU orbit around a Sun-like star were used with a least-squares fit to measure the amplitude of the sinusoidal radial velocity curve. The three conditions in which the mass fit was compared were: evenly-spaced observations with the period unknown; evenly-spaced observations with the period known; and an unevenly-spaced observation method in which observation times are chosen to be very frequent and clustered around the peaks of the radial velocity curve. For evenly-spaced observations, knowledge of the period did not reduce the error in the mass measurement compared to the period-unknown case, though it did allow for the elimination of the false-negative detection case. When observations were evenly spaced, the percent error in the detected mass had a power law relationship with the number of observations of [sigma]%error 1250=N -⁰.⁵. However, when using the knowledge of the period from transits to choose clustered observation times near the peaks of the curve, the error in the mass was reduced by about 20% for the same number of total observations, and was thus approximated by the power law [sigma]%error = 1030N-⁰.⁵. This indicates that if the period of a low-mass planet is known through transits, the use of clustered observations allows its mass to be measured more accurately with the same number of radial velocity observations than if the period were unknown. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2009.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 36) and index.

Mantle thermal evolution of tidally-locked super-earths

Thu, 01 Jan 2009 00:00:00 GMT

Mantle thermal evolution of tidally-locked super-earths Gelman, Sarah E. (Sarah Eva) Most super-Earth (mass < 10M[mathematical symbol]) detection techniques are biased towards massive planets with close-in orbits. A planet's orbital decay timescale decreases with a lower semi-major axis, thereby providing a high probability of detecting exoplanets which are in tidal-lock with their star. We model the effect of fixed stellar flux on an Earth-like planet's mantle convection structure and evolution using an axisymmetric finite element fluid convection code, SSAXC. Three punctuating evolutionary steps have been identified. First, a sequence of three initial downwellings form at the antistellar point, the substellar point, and at the terminator. After approximately 250,000 years, lithospheric instabilities drip down into the mantle, inducing pervasive small scale convective cells. Finally, after 3.5 billion years of planetary evolution, a cold region (~ 300°C) develops at the antistellar point, spanning the depth of the mantle, and inducing a pseudo-Mode 1 convective pattern. Though initial models have focused on an incoming stellar flux equivalent to that at the Earth, we also discuss the possibility of steady-state partial magma oceans in the substellar region induced by higher stellar fluxes. We propose that, though these tidally-locked planets may not be considered habitable in general, they may contain locally habitable regions due to their variety of long-lived extreme environments. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2009.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 37-41).

Determining the effects of ocean perturbations on marine phytoplankton assemblages

Thu, 01 Jan 2009 00:00:00 GMT

Determining the effects of ocean perturbations on marine phytoplankton assemblages Foreman, Alan Dean The ocean provides a dynamic, constantly changing environment for marine phytoplankton. Understanding the effects of these changes on phytoplankton assemblages is fundamental when trying to anticipate future responses of primary producer's community to long-term environmental changes. In this study, artificial perturbation experiments were successfully performed on natural assemblages of phytoplankton to simulate conditions consistent with ocean acidification and North Pacific Subtropical Gyre (NPSG) upwelling patterns. These experiments demonstrated the feasibility and value of such perturbations in studying phytoplankton responses to environmental forcing. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2009.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 34-35).

An overview of the volcano-tectonic hazards of Portland, Oregon, and an assessment of emergency preparedness

Sat, 01 Jan 2011 00:00:00 GMT

An overview of the volcano-tectonic hazards of Portland, Oregon, and an assessment of emergency preparedness Jordan, Alexandra M Portland, Oregon, lies within an active tectonic margin, which puts the city at risk to hazards from earthquakes and volcanic eruptions. The young Juan de Fuca microplate is subducting under North America, introducing not only arc magmatism into the overlying plate, but also interplate and intraplate seismicity related to the subduction zone. Large crustal earthquakes are also probable in Portland because of the oblique strike-slip Portland Hills Fault zone. These hazards create risk to Portland residents and infrastructure because of pre-existing vulnerabilities. Much of Portland's downtown area, including the government and business districts, is at risk of ground shaking infrastructure damage, liquefaction and landslides due to earthquakes. Additionally, the city is within 110 km of three active Cascadia stratovolcanoes, two of which pose hazards from tephra and lahars. Though the city is under the umbrella of four emergency response plans-city, county, state and federal-there are critical gaps in mitigation strategies, emergency exercises and community education and outreach. Portland cannot prevent earthquakes or volcanic eruptions, but the city can reduce its vulnerability to these hazards. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2011.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 106-119).

The formation history of Olympus Mons from paleo-topography

Sat, 01 Jan 2011 00:00:00 GMT

The formation history of Olympus Mons from paleo-topography Jozwiak, Lauren M The formation of the volcano Olympus Mons, is linked directly to the geodynamic history of both Tharsis, and Mars as a whole. We sought to constrain the bulk formation period using paleo-topographic evidence. On the northeastern edge of the flexural trough, we located a lava flow whose path is radically discordant with current down-slope directions, indicating entrenchment prior to large-scale flexural trough formation. To constrain the end of bulk formation, we used the aureole deposits that surround the flanks of Olympus Mons, and were a consequence of crustal fracture under the weight of Olympus. Applying crater retention age dating to images from THEMIS VIS and THEMIS IR, we proposed the bulk formation of Olympus Mons occurred between 3.67 -010+005 Ga and 3.53-0.28+0 09 Ga. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2011.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 34-35).

Measuring channel mobility through the analysis of area-based change in analog experiments, with insights into alluvial environments

Tue, 01 Jan 2008 00:00:00 GMT

Measuring channel mobility through the analysis of area-based change in analog experiments, with insights into alluvial environments Wickert, Andrew David We quantify the mobility of alluvial river channels in order to better understand the relationship between channel mobility and fluvial environment. We analyze five analog experiments, performed between 2002 and 2007 at the Saint Anthony Falls Laboratory, for area-based change in river-channel plan form with time. These experiments isolate the effects of (1) sediment input and deposition, (2) base-level, and (3) bank cohesion on channel mobility. (1) In experimental deltaic environments with aggradation and sea-level rise in equilibrium, aggradation rates scale non-linearly with channel mobility. The channels in the experiment with the higher aggradation rate move more rapidly overall, but the channels in the experiment with slower aggradation are more mobile when both experiments are scaled by their respective aggradation rates. Lower aggradation rates result in lower slopes, causing the flow to be shallower and broader, and for more deposition to occur. These low slopes result in lower Froude number, allowing the formation of flow-depth-high ripples that divert the flow. (2) We study experiments in which base-level change was slow, rapid, and intermediate in terms of average channel mobility when base-level is constant. Channels in an experimental basin with rapid (12.2 mm/hr) aggradation are three times as mobile during base-level rise as during base-level fall. Channels in a cohesive delta experiment (producing significantly lower channel mobility) are 1.5 times as mobile during slow base-level rise (0.237 mm/hr) as during steady base level. Base-level change that is slow on an average channel mobility timescale has little to no influence on channel mobility. (3) Channels in an experimental system of noncohesive sediment are 6.5 times as mobile as channels with alfalfa (Medicago sativa) planted in the flume. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, June 2008.; Cataloged from PDF version of thesis. "31 May 2007."; Includes bibliographical references (pages 125-128).

Elemental and reactive gaseous mercury deposition and diurnal cycles over terrestrial environments

Sat, 01 Jan 2011 00:00:00 GMT

Elemental and reactive gaseous mercury deposition and diurnal cycles over terrestrial environments Maheras, Anastasia Francis The atmospheric component of the global biogeochemical mercury cycle was studied to determine the mechanisms behind diurnal trends and amplitudes in elemental and reactive gaseous mercury concentrations over terrestrial environments. This analysis was done using the 3D GEOS-Chem chemical transport model and the creation of a simple one-box model. Mercury is a significant neurotoxin for humans and other species that has been addressed in the policy realm on both national and international levels. Being able to model atmospheric mercury processes correctly is an important part of regulation and policy drafting. GEOS-Chem model results were compared with Weiss-Penzias et al. [2009] measurements for three Nevada, USA sites. The magnitude of elemental mercury concentrations differed by 0.07-0.2 ng/m3 , with GEOS-Chem underestimating concentrations due to an under-representation of mercury emissions at naturally enriched sites. The amplitude of reactive gaseous mercury diurnal variations differed by a factor of 3-4, with GEOS-Chem underestimating the diurnal trend. Based on the diurnal nature of this error, it is hypothesized that GEOS-Chem under represents the magnitude of elemental mercury emissions, the amount of oxidation occurring in the atmosphere, and the scale of entrainment from the free troposphere. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2011.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 88-93).

Determining the concentration of lead in MIT athletic facilities and estimating student-athlete exposure to lead

Thu, 01 Jan 2009 00:00:00 GMT

Determining the concentration of lead in MIT athletic facilities and estimating student-athlete exposure to lead Barnard, Alison M In April of 2008, there were reports of elevated lead levels in several AstroTurf surfaced fields in New Jersey that motivated this investigation of MIT's synthetic turf field and other athletic facilities for elevated lead levels. I have analyzed samples of chalk, paint, dust, water, air, and synthetic turf fibers for lead concentration and isotopic composition by thermal ionization mass spectrometry. Additionally, blood lead levels were tested in a student-athlete and a non-athlete for control. The synthetic turf, water, chalk, and air analyzed from the athletic facilities were found to pose no significant lead hazard for student-athletes using the facilities, and the tested student-athlete had a normal blood lead level. The dust and paint did not pose a significant hazard to student athletes, but hazardous levels of lead were found in some dust and paint samples. It is recommended that further studies of the lead in duPont Gymnasium paint and Rockwell and duPont Gymnasium dust be performed and the potential hazards to be investigated. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2009.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 63-66).

Observations from working with a simple mathematical model of light absorption by small particles in the ocean

Tue, 01 Jan 2008 00:00:00 GMT

Observations from working with a simple mathematical model of light absorption by small particles in the ocean Tay, Derric (Derric G.) In order to investigate the possibility of using oceanic visual spectrum data (i.e., ocean color) to differentiate between phytoplankton cell types, a simple mathematical model of light absorption was constructed in MATLAB, in order to investigate the effects of depth, cell size, and water on light absorption by a layer of water containing suspended particles. The model takes chlorophyll a absorption data, cell diameter, intracellular and bulk concentrations of chlorophyll a, pure water absorption data, and thickness of water layer as inputs, and outputs the attenuation by absorption of light that shines through a layer of water containing suspended, absorbing cells. Plots of absorptive attenuation were made, varying thickness, cell diameter, and inclusion of water absorption. These plots were qualitatively analyzed. It was found that water greatly dominates absorption, when included. This finding suggests that using visual data may be difficult with ocean water, though scattering effects remain to be accounted for, and thus this problem warrants further study. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2008.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 48).

Using thermochronology to constrain exhumation in the Swiss-Italian Alps

Tue, 01 Jan 2008 00:00:00 GMT

Using thermochronology to constrain exhumation in the Swiss-Italian Alps Stanley, Jessica R Twelve bedrock samples were collected from Ticino, Switzerland and Northern Italy for thermochronological studies using the (U-Th)/He technique on zircon and apatite and fission track on subset of zircons. Nine samples were collected from the Lepontine Dome, north of the Insubric Line, six of which were in an approximate vertical, or elevation, transect. Three samples were also taken in a vertical transect from the Southern Alps, south of the Insubric Line. (U-Th)/He Zircon dates from north of the Insubric line ranged from 7 to 14 Ma, and indicate an approximate exhumation rate for the region of 1000 m/Ma. U-Th/He zircon dates from south of the Insubric Line ranged from 100 to 180 Ma, with one reliable apatite date of 23 Ma. These data lead to an approximate exhumation rate of 20 m/Ma in the south with rates increasing to about 150 m/Ma since 23 Ma. Thus very different exhumation histories can be inferred north and south of the Insubric Line, with the north side showing much younger dates and a higher exhumation rate related to continued orogenic activity, whereas to the south, there are lower rates and older dates indicating little to no orogenic activity until ca 23 Ma. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2008.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 52-56).

Modeling the sorting of sediments on delta tops

Thu, 01 Jan 2009 00:00:00 GMT

Modeling the sorting of sediments on delta tops Baumgardner, Sarah E Sediment sorting in fluvial rivers produces great variation in the grain-size of deposit over the length of a river. Knowledge of the pattern of sediment deposition may help to shed light on the processes that sort by grain size. A simple geometric model was developed to predict the location of the transition between coarse and fine sediment in a bimodal sediment distribution and tested against flume-created deposits with a variety of flow and depositional conditions. The models agreed well with the overall form of plane-bed clinoform deposits but not with rippled-bed clinoform deposits, thus a new model for predicting transitions in rippled-bed deposits is needed. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2009.; Cataloged from PDF version of thesis. Page 40 blank.; Includes bibliographical references (pages 36-37).

Evaluating the use of Sr, Pb, and U isotopes for fingerprinting surface and groundwaters in southern New Hampshire

Tue, 01 Jan 2008 00:00:00 GMT

Evaluating the use of Sr, Pb, and U isotopes for fingerprinting surface and groundwaters in southern New Hampshire Song, Lisa Increased pressure on fresh water reserves in southern New Hampshire requires new methods for monitoring exploitation. In a pilot study, surface water and groundwater samples from southern New Hampshire were analyzed for Sr, Pb, and U isotopes to test if they could be used to distinguish between different reservoirs (surface waters, bedrock wells, and sand and gravel wells). Detecting and monitoring communication between different aquifers is an essential part of water management, and mixing between the reservoirs due to overproduction of the wells could adversely impact drinking water quality. The results show that a mix of ²³⁴U/²³⁸U, ²⁰⁶Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb ratios was the most useful in distinguishing between the reservoirs. This method has great potential for the long-term monitoring of water wells to prevent overproduction. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2008.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 50-52).

Modeling sea surface height in the Gulf of Mexico

Tue, 01 Jan 2008 00:00:00 GMT

Modeling sea surface height in the Gulf of Mexico Rigel, Adam C A model was created to form synthetic plots of sea surface height (SSH) from monthly SSH statistics in the Gulf of Mexico generated from satellite laser altimetry data. SSH is a signal of the upper ocean mixed layer heat content and is an input for hurricane intensity models. A significant ocean feature in the Gulf of Mexico is the Loop Current (LC) which sheds warm eddies into the Gulf of Mexico at irregular intervals, which adds to the variability in monthly SSH readings beyond seasonal change. Satellite laser altimetry data was used from October 14th 1992 to May 23rd 2007. The SSH data included an area of the Gulf of Mexico (16°N-30°N latitude, 80°W-100°W longitude) with a resolution of 1/3° by 1/3° on a Mercator grid. Monthly SSH averages, variances, and covariances were created from a total of 763 samples, which allowed for approximately 65 samples per month. Once monthly SSH averages, variances, and covariances were made, synthetic plots were made by using a Karhunen-Loève transform, the Singular Variable Decomposition of the SSH monthly covariance, and random vector composed of random numbers in a Gaussian distribution. Differences in synthetic SSH plots compared to individual SSH observations could vary greatly; the average of all synthetic SSH plot nodes differed by no more than plus or minus 10 cm. The difference between observed and synthetic SSH variance was no more than 400 cm². The large differences occurred in the in the eddy shedding region of the LC. To assess the effectiveness of the model, the synthetic SSH model will need to be used in a hurricane intensity model. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2008.; Cataloged from PDF version of thesis. "May 9, 2008."; Includes bibliographical references (pages 25-26).

Investigation of regional variation in Lunar crater morphometry from (Lunar Orbiter Laser Altimeter) LOLA observations

Sat, 01 Jan 2011 00:00:00 GMT

Investigation of regional variation in Lunar crater morphometry from (Lunar Orbiter Laser Altimeter) LOLA observations Talpe, Matthieu Jean The advent of global Digital Elevation Models of the lunar surface, obtained from the Lunar Orbiter Laser Altimeter (LOLA), has allowed for a quantitative assessment of crater morphometry. 351 simple and complex craters in the Mare Serenitatis, far side highlands, near side highlands, and South Pole-Aitken basin are decomposed into 50 elevation profiles, from which key geometric crater properties are extracted. The geometric properties and their respective standard variation, such as height-to-diameter ratios, and average elevation profile are compared on a global level to investigate regional differences in terrain rheology and study the transition between the simple and complex crater regime. Furthermore, the relationship between known degradation mechanisms and crater morphometry is discussed, as well as the current state of quantitative methods to assess crater degradation. The resulting regional differences observed in crater morphometry are explained in the context of lunar geologic history. Finally, the addition of other crater geometric properties in future quantitative assessments will broaden the study of crater morphometry, and improvements to current methods are necessary to conclusively define degradation states in terms of quantitative factors. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2011.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 41-42).

Decarbonization related to continental arc magmatism as a possible mechanism for Cretaceous warming

Sun, 01 Jan 2012 00:00:00 GMT

Decarbonization related to continental arc magmatism as a possible mechanism for Cretaceous warming Brunner, Anna Elizabeth Elevated concentrations of CO₂ have been proposed as the reason that the Cretaceous climate was 6-14°C warmer than the present, however the source of Cretaceous CO₂ is unknown [Barron, 1983]. This study examines the possibility of continental arc magmatism as a mechanism for CO2 release, specifically as a volatile produced during crustal assimilation and contact metamorphism of carbonates around plutons. Bedrock maps of the North American Cordillera (a region of active continental arc magmatism during the Cretaceous), the relative locations of the carbonates, the Cretaceous plutons, and the calculated "decarbonation zones"around the plutons. These measurements were then input in a thermal and petrologoical model in order to estimate the quantity of CO₂ released by continental arc magmatism. Testing a number of cases with varying parameters, the model found the arc-magmatism-induced temperature difference between the present and Cretaceous global climates to have a lower limit of [Delta]T < 1°C and an upper limit of 5.1 < [Delta]T < 12.3°C. Decarbonation from continental arc magmatism is shown to be a possible mechanism of paleoclimatic warming, and more work is required to either confirm or refute the hypothesis. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 53-56).

Paleomagnetism of Lonar impact glass

Tue, 01 Jan 2008 00:00:00 GMT

Paleomagnetism of Lonar impact glass Pedersen, Shelsea A. (Shelsea Anne) Several dozen impact glasses from Lonar Crater, in Maharashtra, India, were analyzed for evidence of impact-generated paleofields, and possible motional remanent magnetization. Lonar Crater formed when a meteorite impacted a bed of Deccan Trap basalts. Upon impact, the basalt was super heated into a fluid melt that would have been ejected from the crater, moving at speeds that allowed the smaller pieces of basalt to cool in mid-air. These smaller pieces would have cooled instantaneously, and due to their ferromagnetic composition may have recorded the presence of an impact generated magnetic field. This paper focuses on analyzing several dozen basaltic glass samples from the perimeter of Lonar Crater that are considered to be some of the most plausible known terrestrial analogs to the lunar impact glasses. Lonar impact glasses could serve as a decent analogue to lunar tektites, although differences in their rotational NRM and grain size suggest that they may not be the best recorders of paleointensity. The impact glasses display clear evidence of a series of wild, directionally unstable magnetic moments when heated to temperatures in excess of 400 to 500°C that are not observed in other terrestrial samples. The simplest explanation for this unusual behavior is that these randomized magnetic moments are the result of the progessive removal of different magnetization moments that had, up until the higher temperatures, been blocked in. Upon their removal, these randomized high temperature moments were revealed. Based on the NRM/sIRM ratios of the splash-form spherules the glasses slightly underestimate the intensity of the field in which they cooled. This underestimate is in part possibly due to the effects of rotation during cooling. Their unique motional remanent magnetization is quite fascinating, but may be detrimental to the spherules' ability to retain a strong enough NRM, preventing them from displaying evidence of an impact-generated paleofield at Lonar Crater. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2008.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 65-68).

Impact modification of Mercury's mantle composition

Sat, 01 Jan 2011 00:00:00 GMT

Impact modification of Mercury's mantle composition Wahl, Sean M Difficulties encountered in reproducing Mercury's compositional attributes through modeling of formational processes have bolstered support for the hypothesis that one or more giant impacts stripped away a significant proportion of proto-Mercury's silicate mantle. Previous investigations demonstrate sufficient removal of mantle material to account for the planets unusually high mean density, but do not consider the effects of multiple silicate and oxide phases. In this study, we extend the present theory by investigating the consequences of a more realistic chemical model on the evolution of the ejected material. We suggest that the majority of condensation within the expanding vapor plume can be modeled as an equilibrium process following homogeneous nucleation of refractory phases leading to larger particle sizes than previously estimated. We use a thermodynamic model focused on major element composition of ejected material to analyze the effect of differential condensation on the expansion and final state of ejecta. We also adapt pre-existing models for chemistry of condensation and impact shock compression to address additional problems associated with the process. For ejecta of sufficiently high specific entropy, our simplified chemical models indicate that energy released during condensation of MgO-rich phases buffers the temperature, delaying or preventing onset of FeO condensation. If sufficient spatial separation between condensates and vapor arises or if significant amounts of uncondensed FeO vapor remain uncondensed, reaccumulated ejecta would be enriched in MgO and refractory phases. This is compatible with an FeO depletion of Mercury's surface relative to other terrestrial bodies as some spectroscopic data suggests. The proposed process leads to a greater depletion in FeO and a lesser depletion in refractory, incompatible elements (Al2 O3, CaO, TiO2 ), than models assuming uniform removal of material from a differentiated proto-Mercury. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2011.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 53-57).

Magmatic processes that generated the rim andesites of Medicine Lake Volcano, N. California

Sun, 01 Jan 2012 00:00:00 GMT

Magmatic processes that generated the rim andesites of Medicine Lake Volcano, N. California Fuentes, Jocelyn J This paper characterizes the compositionally distinctive high-Na andesite lavas at Medicine Lake Volcano that erupted at ~100 ka and that built most of Medicine Lake's caldera. These high-Na lavas define a compositional trend that formed by fractional crystallization in a shallow magma chamber (~ 4 to 8 km). Petrologic evidence indicates pre-eruptive H20 contents of 2 to 4 wt.% H20 over a temperature range of 1070 to 900 C. Oxygen fugacity recorded in coexisting spinel and rhombohedral oxides varies from NNO (Nickel - Nickel Oxide) to NNO 0.7 log units. Experiments performed at 1 kbar - H20 saturated conditions at the NNO buffer on a primitive andesite reproduce most of the major element compositional variability exhibited in the high-Na lavas. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages [32]-[34]).

The Green's function for the diffusion coefficient

Sun, 01 Jan 2012 00:00:00 GMT

The Green's function for the diffusion coefficient Hess, Clarion Hadleigh The scattering diffusion coefficient between two points can theoretically be extracted from a random distribution of sources. An improved ability to measure the diffusion coefficient of the Earth's crust would simplify the process of characterizing the fracture network for applications in geothermal energy. This has the potential to make geothermal wells more economical to make, more efficient to operate, and longer lived. Previous work has shown the diffusion coefficient can be extracted from synthetic datasets in both one dimension and three dimensions using seismic interferometry. This paper attempts to recover the diffusion coefficient for a realistic source distribution taken from a microseismic dataset from a geothermal field in Indonesia. This dataset did not have an ideal distribution of sources, so the estimated diffusion coefficient did not match the expected value. A better estimate of the expected diffusion coefficient and an improved dataset with sources more evenly distributed in all directions around the receivers would likely give a better result. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 53-54).

Exploring the microbe-mediated soil H² sink : a lab-based study of the physiology and related H² consumption of isolates from the Harvard Forest LTER

Sun, 01 Jan 2012 00:00:00 GMT

Exploring the microbe-mediated soil H² sink : a lab-based study of the physiology and related H² consumption of isolates from the Harvard Forest LTER Rao, Deepa,Ph.D.Massachusetts Institute of Technology. Atmospheric hydrogen (H²) is a secondary greenhouse gas that attenuates the removal of methane (CH⁴) from the atmosphere. The largest and least understood term in the H² biogeochemical cycle, microbe-mediated soil uptake, is responsible for about 80% of Earth's tropospheric H² sink. A recent discovery of the first H²-oxidizing soil microorganism (Streptomyces sp. PCB7) containing a low-threshold, high-affinity NiFe-hydrogenase functional at ambient H² levels (approx. 530 ppb) made it possible to identify a model organism to characterize microbial H²-uptake behavior. In the present research, several strains of Streptomyces containing the high-affinity NiFe-hydrogenase were isolated from the Harvard Forest LTER and used to characterize H² uptake alongside analysis of their life cycles. It was found that containing the gene encoding for the specific hydrogenase predicted H² uptake behavior in the wild Streptomyces strains and also in more distantly related organisms that contained the gene. The H² uptake rates were correlated with the microorganisms' life cycles, reaching a maximal uptake corresponding with spore formation. Understanding how environmental conditions, organismal life cycle, and H² uptake are connected can help reduce the uncertainty in atmospheric models. With the rise of H²-based energy sources and a potential change in the tropospheric concentration of H² , understanding the sources and sinks of this trace gas is important for the future. Thesis: Ph.D., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 91-92).

Investigation of the depth and diameter of simple craters in the lunar mare

Sun, 01 Jan 2012 00:00:00 GMT

Investigation of the depth and diameter of simple craters in the lunar mare Clark, Madeline E Using altimetry data from the Lunar Orbiter Laser Altimeter (LOLA), the depths and diameters of 1429 simple craters in six different lunar maria units were measured, The analysis utilized a Graphical User Interface that was developed to access the LOLA data base and measure crater depth and diameter.The craters were compared to a published trend of depth/diameter relationships for fresh craters by Pike. By and large, the measured craters were shallower than the fresh crater trend. The pattern of shallowing did not correlate with the age of maria units, indicating a complex pattern of basin degradation. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 33).

Testing general relativity using millimeter wavelength radio interferometry of Sgr A*

Sun, 01 Jan 2012 00:00:00 GMT

Testing general relativity using millimeter wavelength radio interferometry of Sgr A* Ruprecht, Jessica Dawn General relativity, though widely accepted in the weak-field limit, is difficult to test in the strong-field regime. Millimeter wavelength VLBI offers a unique opportunity to resolve the black hole structure on event-horizon scales. The ability of millimeter wavelength VLBI observations of Sgr A* to constrain black hole parameters such as mass, spin, and deviation from general relativity was considered. Realistic simulations of Sgr A* were performed using the MAPS software. Image reconstructions were made using MACIM and image-based parameter extraction using the Hough transform was considered. Non-imaging techniques using least-squares fitting of a simple ring and gaussian model to VLBI amplitudes and closure phases were considered. The Hough transform is not able to place strong constraints on black hole parameters. Least-squares fitting techniques indicate possible sensitivity to deviations from general relativity and prove able to extract the photon ring radius to within 5-7% of the expected value. It is concluded that VLBI observations of Sgr A* represent a promising opportunity for testing general relativity in the strong-field regime. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 77-78).

Pluto's atmosphere from the May 22, 2011 stellar occultation

Sun, 01 Jan 2012 00:00:00 GMT

Pluto's atmosphere from the May 22, 2011 stellar occultation Sallum, Stephanie E This paper reports the observations and atmospheric fitting results from the May 22, 2011 stellar occultation by Pluto. Of the nine sites across the United States that attempted to observe the event, three obtained light curves at the predicted midtime without being clouded out. Simultaneous fitting of these three light curves utilizing a model fully detailed in Elliot and Young [1992] resulted in a best fit half-light radius of 1309 ± 25 km, a calculated temperature of 94 ± 4 K, and a calculated pressure scale height of 55 ± 2 km. These parameters, in the context of the previous occultations, reveal a trend in which Pluto's half-light radius has been increasing slightly since an initial dramatic increase between 1988 and 2002. While the pressure scale height has remained relatively constant, the temperature has decreased slightly over the recorded events. The changes in half-light radius agree with frost migration models in which Pluto's surface has a low thermal inertia [Hansen and Paige, 1996; Elliot et al., 2007], but further constraints on frost migration model parameters such as substrate and frost albedo, frost emissivity, and the supply of N2 require additional observations. The New Horizons spacecraft should encounter a dynamic atmosphere on Pluto during the scheduled fly by in 2015. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 40-41).

The role of precipitation on Bedrock Channel Incision in Kauai, HI

Sun, 01 Jan 2012 00:00:00 GMT

The role of precipitation on Bedrock Channel Incision in Kauai, HI Slosberg, Michelle I Erosion of bedrock channels is frequently modeled with the stream power law, which relates erosion rates to drainage area, slope, and an erosional efficiency coefficient k. The value of k, however, varies with many physical factors and most of these relationships are not well quantified. This study uses a form of stream power dependent on mean annual precipitation. The island of Kauai in the Hawaiian island chain is used as a case study due to the island's steep precipitation gradient and relatively constant lithology. Erosion rates are calculated by constructing splines to approximate the island's shape at the end of the shield-building phase, and these data are used to calculate erosion rates. The precipitation-dependent stream power model is tested with a multiple regression analysis of the Kauai data. Erosion rates are positively correlated with precipitation rates and erosional efficiency is related to precipitation rate by a power of ~0.4. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 35-38).

Rotational lightcurve analysis of binary Asteroid (22) Kalliope/Linus

Tue, 01 Jan 2008 00:00:00 GMT

Rotational lightcurve analysis of binary Asteroid (22) Kalliope/Linus Kramer, Emily Anne Binary asteroids have been insightful to scientists in recent years in their quest to better understand the Solar System in its early stage. Observing a mutual event between a primary and its moon can yield the sizes of the objects in units of the semi-major axis a. When the linear dimensions of the orbit can be known, Kepler's Third Law allows for a solution of the mass. As an example, because the absolute linear scale of (22) Kalliope/Linus is known [1], one can determine the component sizes and reduce error bars on the mass and density of this M-type asteroid. Since the bulk composition is known from spectral data, the porosity of the asteroid can be calculated. Knowing the porosity of the asteroid can give scientists a better understanding of its formation and dynamical evolution. Binary object (22) Kalliope/Linus is a classic example of a system for which this technique can yield valuable results. An observing campaign involving five observers resulted in twenty-eight nights of data. The data were used to create rotational lightcurves, which were scanned for signatures of mutual events. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2008.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 34).

Characterization of a 3D printed pumped counterflow virtual impactor and an aerodynamic lens concentrator

Sun, 01 Jan 2017 00:00:00 GMT

Characterization of a 3D printed pumped counterflow virtual impactor and an aerodynamic lens concentrator Koolik, Libby (Libby P.) Atmospheric aerosols have an important role in cloud formation and, by extension, in the overall climate system. Field studies are required to refine the uncertainty associated with the net radiative effect of atmospheric aerosols. Two pre-existing cloud sampling devices, the pumped counterflow virtual impactor (PCVI) and aerodynamic lens concentrator (ADL), were modelled using computer aided design software and printed using stereolithography printing. These devices were compared against their industrial counterparts. The printed PCVI was proven to be as effective as the industrial PCVI in a smaller working range. The printed concentrator effectively concentrated particles, but at a lower concentration factor than the industrial concentrator. This study revealed potential for further refinement in design features for both devices and it served as an essential pre-study for future field campaigns that will use these 3D printed devices. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 11-12).

Precursors to atmospheric blocking events

Tue, 01 Jan 2008 00:00:00 GMT

Precursors to atmospheric blocking events Marino, Garrett P Atmospheric blocking disturbs synoptic-scale features from their normal eastward progression, causing extreme weather conditions for the duration of the blocking event. Blocking precursors, as indicators of meridional flow preceding the onset of strong Atlantic blocking episodes, have been identified by using a modified version of the Tibaldi and Molteni blocking index (1990). Hovmoller diagrams of the modified index were found to be particularly useful in finding the potential cases, clearly showing a precursor signal propagating from the western United States down to the Atlantic to initiate the blocking pattern. A composite of the 14 cases identified showed the precursor pattern to be consistent with the positive phase of the PNA, while the composite mature phase of Atlantic blocking resembles the negative NAO and AO phases. The results suggest that blocking is a global, rather than localized, phenomenon. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2008.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 51-55).

Imaging of the Hellenic subduction zone by seismic tomography

Tue, 01 Jan 2008 00:00:00 GMT

Imaging of the Hellenic subduction zone by seismic tomography Hosa, Aleksandra M The Hellenic subduction zone is a complicated tectonic boundary, along which transitions in the nature of subducted material are believed to occur. The objective of this study was to better constrain the subsurface geometry of the Hellenic subduction zone by increasing the resolution of an existing tomographic model of the region. Increase in resolution is important for understanding the effects of inferred transitions in subducted material at depth. Nonlinear inversion of P-wave travel times was used on a global dataset expanded by temporary array data collected in southern Greece. Results show a vertically continuous slab, with a break at the depth 200-400 km detected only in the NW portion of the system. At depth above 400 kin, there is a lateral discontinuity marked by the Central Hellenic Shear Zone and Kephalonia Transform Fault, with slab more pronounced in southern part of the system. Our study supports the hypothesis of the change in subduction mode between northern and southern part of Hellenic arc in late Pliocene. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2008.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 24-25).

Molecular toxicity of lead

Tue, 01 Jan 2008 00:00:00 GMT

Molecular toxicity of lead Jacox, Laura (Laura A.) Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2008.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 23-28).; Introduction - Lead is a heavy metal that has been in use for over 8000 years (White, 2007). It was first smelted it 4000BC as a byproduct of silver processing. Since then, Pb has played a dynamic role in history, possibly contributing to the fall of the Roman Empire (Nraigu, 1983). Pb is a highly malleable and ductile Group IVa metal. It has been utilized in a variety of products including makeup, water pipes, cooking vessels, wine bottle seals, glass, batteries, solder, electronic components, paint, and antiknock fuel additives (White, 2007). Its prevalent, long-term use has distributed anthropogenic Pb across the planet in soil, air-borne dust, and water (White, 2007). As a result, human exposure can occur via inhaled air, dust, food, and drinking water. Pb has no known biological functions, yet it has numerous detrimental effects on the body, several of which have been recognized for millennia.

Remanent magnetization in angrite NWA 4931

Tue, 01 Jan 2008 00:00:00 GMT

Remanent magnetization in angrite NWA 4931 Berdahl, James Scott Angrites are among the oldest known rocks and may record planetesimal dynamo activity and protoplanetary disk fields in the early solar system. Towards this goal, the natural remanent magnetism and its origin were examined in newly discovered angrite NWA 4931. Measurements were conducted on subsamples cut from various distances along a drilled core sample of the meteorite. The samples were then progressively demagnetized to isolate primary magnetization from contaminant overprints and to calculate paleofield intensity. Dust produced during the subsampling process was analyzed to determine that the mineralogical source of the magnetism was magnetite. Analyses of fusion crusted and adjacent samples showed that the exterior of the meteorite had been contaminated by a collector's hand magnet. However, the interior of the core yielded a pristine record, indicative of a paleointensity strength on the order of 25 [mu]T. These results, in light of magnetic measurements on other angrite samples, are suggestive of a core dynamo active for at least seven million years on the angrite parent body, beginning by 4564 Ma. Thesis: S.B. in Geoscience, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2008.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 26-27).

Spontaneous tropical cyclogenesis in a cloud revolving numerical model

Tue, 01 Jan 2008 00:00:00 GMT

Spontaneous tropical cyclogenesis in a cloud revolving numerical model Hoffman, Paul M., S.B. Massachusetts Institute of Technology In this thesis, spontaneous tropical cyclogenesis occurring in a cloud-resolving numerical model is studied. The model environment is one of radiative convective-equilibrium on an f-plane with doubly periodic boundary conditions and constant sea surface temperature. While a variety of initial conditions may exhibit spontaneous tropical cyclogenesis, this study focuses on one. Using assumptions of axisymmetry for the growing disturbance and focusing on the large scale processes, fields were created for a number of thermodynamic variables along constant height surfaces and as azimuthal means plotted against height. The tropical cyclone is hypothesized to develop in three steps. First, convective aggregation creates regions of high moist static energy, and regions of cold dry air. Importantly, a deep moist column is created which provides a perfect environment the developing storm. In the second step, mid-level cyclone intensification, a mid-level cold core cyclone develops in the deep moist region, and benefits from moist static energy and potential vorticity fluxes from the upper troposphere. Exhibiting anticyclonic convergent flow, the upper troposphere is an unlikely source for the mid-level disturbance, while convective downdrafts and divergent surface flow hinder energy transport from the ocean to the growing system. In fact, a cold surface anticyclone exists near the center for much of the second step. It is not until potential vorticity anomalies advect down to the surface that the final step, low-level cyclone intensification, creates a classical hurricane structure. Potential vorticity advection stimulates cyclonic flow at the surface, extinguishing the surface anticyclone, and thereby linking the mid-level disturbance to the oceanic energy source. While like some cold core cyclones previously studied, the anticyclone as an energy source is unique to this spontaneous case. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2008.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 24).

High-precision U/Pb dating of the Cenomanian-Turonian boundary Kaiparowits Plateau, Utah

Sun, 01 Jan 2012 00:00:00 GMT

High-precision U/Pb dating of the Cenomanian-Turonian boundary Kaiparowits Plateau, Utah Stangroom, Amber M The massive marine species turnover at the Cenomanian-Turonian boundary is associated with Oceanic Anoxic Event 11 (OAE II) and is often identified by an increase of a13C in the carbon isotopic record. A high-precision chronology of the Cenomanian- Turonian boundary is needed to better constrain the cause, timing, and extent of OAE II. To create such a timeline, four bentonite samples from the Kaiparowits Plateau, Utah were dated using U/Pb geochronology. The Cenomanian-Turonian boundary is constrained to be 94.040 ± 0.029/0.098/0.14 Ma, in agreement with recent astrochronologic studies of the same time period. This research will help improve the calibration of the astronomical time scale, as well as provide a greater understanding of the Cretaceous environment.. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 33-40).

Determining the concentration and source of lead in chocolate using lead isotopes

Mon, 01 Jan 2007 00:00:00 GMT

Determining the concentration and source of lead in chocolate using lead isotopes Thompson, Jessica Ann Single-origin dark chocolate samples derived from cocoa grown in developing countries from around the world were analyzed to determine their lead concentrations and the isotopic composition of the lead. The lead isotope ratios were compared with published data from aerosols and volcanic rocks nearest to the cocoa growing regions. Samples from different countries and manufacturers were compared, and we conclude that the source of lead depends on the country of origin and not the manufacturer. Chocolates grown in the Northern Hemisphere usually had lead isotope ratios that matched the global atmospheric lead isotopic signature from the Northern Hemisphere. Chocolates grown in the Southern Hemisphere did not match the global signature, but rather more closely matched the lead isotopic signature from volcanic rocks in their respective countries, and had a lower average lead concentration than chocolates from the Northern Hemisphere. Soils from Venezuela were also analyzed, and confirmed the conclusion that atmospheric lead is the predominant source of bioavailable lead. Many of the chocolates also had lead concentrations below the limit of 0.1 ppm set by the FDA; however, one manufacturer, Dagoba, consistently had lead concentrations above the limit. The percent of cocoa in each chocolate bar was also compared with the lead concentrations, concluding that the concentration of lead is not necessarily dependent on the amount of cocoa in the bar. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2007.; Cataloged from PDF version of thesis. Pages 81 and 87 missing from original thesis.; Includes bibliographical references (pages 86-91).

Predicted and observed free-air gravity anomalies for delamination models of the formation of the Siberian Flood Basalts

Mon, 01 Jan 2007 00:00:00 GMT

Predicted and observed free-air gravity anomalies for delamination models of the formation of the Siberian Flood Basalts Rosenburg, Margaret Anne The mechanism responsible for the formation of the Siberian Flood Basalts (SFB) has yet to be discovered and adequately quantified. One theory proposes that thinning of the lithosphere due to delamination triggered the eruption. This model is characterized by a drip of denser material within the mantle, and because it involves a density-driven process, calculations of predicted gravity at the surface can be used to test the model. Temperature, composition, and stress output from the delamination model presented in Elkins-Tanton (2007) were used to calculate predicted gravity measurements at the surface. These predictions were then compared to gravity observations of the SFB, focusing on the potential eruptive center at Noril'sk. Model runs in both Cartesian and axisymmetric coordinates were analyzed, and each run predicted a negative anomaly over the site of the drip with a magnitude ranging from 20 to 50 mGal. In the observations, an average radial gravity profile centered on Noril'sk also contained a slight negative anomaly at the center, suggesting partial agreement with the delamination theory. Because the amplitude of the observed gravity anomaly is substantially smaller than the predicted amplitude, the qualitative agreement is encouraging, but not definitive. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2007.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 30).

The Day Nui Con Voi mylonitic belt in Southwestern China and Its implications for the early Cenozoic extrusion of Indochina

Mon, 01 Jan 2007 00:00:00 GMT

The Day Nui Con Voi mylonitic belt in Southwestern China and Its implications for the early Cenozoic extrusion of Indochina Swanson, Erika M The early Cenozoic India-Asia collision resulted in the extrusion of large crustal fragments southeast from the Eastern Himalayan syntaxis, with large shear zones at their boundaries that could have accommodated displacements of hundreds to perhaps a thousand kilometers. Along the northeastern edge of the Indochina extruded fragment, the belt of mylonitic metamorphic rocks generally referred to as the Ailao Shan/Red River shear zone forms the extrusion boundary. This shear zone actually consists of at least two belts, the Ailao Shan and the Day Nui Con Voi, which are separated by a narrow belt of unmetamorphosed Triassic sedimentary rocks. In the Chinese extension of the Day Nui Con Voi, the presence of sillimanite and garnet indicates the shear zone formed at amphibolite grade, and the mylonitic fabric defined by muscovite and biotite indicate left-lateral shearing. Ar/Ar cooling ages indicate the metamorphic rocks reached the cooling temperature of muscovite and biotite 26.07 ± 0.20 to 32.46 ± 0.25 Ma, ages that match those in the Day Nui Con Voi in north Vietnam. These data come from both the core orthogneiss of the shear zone as well as a narrow carapace of metasedimentary rocks of unknown age. Both rock units form an antiform in southern China that plunges below Triassic sedimentary rocks of South China. These relations show that: 1) the Day Nui Con Voi in China is the direct continuation of the same belt in north Vietnam, 2) the Day Nui Con Voi does not directly connect with the Ailao Shan shear zone, 3) the Day Nui Con Voi shear zone has a structural (?) cover of South China Mesozoic sedimentary rocks, 4) structural relations limit the amount of late stage left-lateral shear on the Indochina boundary, and 5) the structural relations require a more complex history for the shear zone along the NE boundary of the extruded Indochina crustal fragment than proposed by all earlier workers. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2007.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 42-43).

A comparison of kinematic and dynamic schemes for calculating long-range atmospheric trajectories

Sun, 01 Jan 2017 00:00:00 GMT

A comparison of kinematic and dynamic schemes for calculating long-range atmospheric trajectories Schneider, Allison (Allison M.) Two numerical models, one kinematic and one dynamic, were created and compared in their ability to predict trajectories of atmospheric parcels over eight days. While kinematic models are more widely used due to their accuracy, dynamic models can be used pedagogically to visualize the balance of forces in the atmosphere. The kinematic model used gridded wind speed data from the Global Forecast System (GFS) to predict parcel flow, while the dynamic model calculated wind speeds from advection equations using geopotential height fields from GFS. The trajectories of ensembles of parcels were simulated from five launch locations. The spread of parcels from each location was calculated along with the deviation from reference trajectories. The dynamic model performed comparably to the kinematic model, despite the presence of inertial oscillations in some computed trajectories at mid- and high- latitudes which are likely to be physically unrealistic. The dynamic model was more sensitive to changes in spatial resolution than the kinematic model. Dynamic trajectory models were shown to be accurate enough to be used as a tool to visualize the interplay of forces acting in the atmosphere. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 57-58).

Time series photometry of the dwarf planet Eris

Mon, 01 Jan 2007 00:00:00 GMT

Time series photometry of the dwarf planet Eris Pike, Rosemary Ellen This project utilizes time series photometry to attempt to find the period of the newly discovered Kuiper Belt Object (KBO), Eris. Eris is known to have a radius slightly larger than Pluto and an extremely high albedo of 86%, indicative of fresh surface ices. This high albedo makes it likely that the brightness variations of Eris are small and difficult to detect. The data for this project were collected using the Swift Ultra Violet Optical Telescope (UVOT) over 29 nights. The 266 good images were analyzed using aperture photometry on Eris and 33 reference stars. A least squares fit was applied to correct for changes in overall image brightness, and Eris' magnitude was plotted over time. A periodogram was used to search for a periodic solution, but did not yield a significant signal. This means that the rotation period of Eris was below the detection limit of the data, so this detection limit was calculated. For a 6 hour period, the data would have had a 2 sigma significance for a full amplitude of 0.16 magnitudes, a 12 hour period is 0.125 magnitudes, an 18 hour period is 0.155 magnitudes, and a 24 hour period is 0.185 magnitudes. Knowing the detection limit of this data set helps to constrain future observations. In order to determine a period for Eris, new data would have to be more sensitive than these magnitude change detection limits. These results also make the 5-day period proposed by Carraro et al. (2006) unlikely, as this data set shows no periodogram peaks at that frequency. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2007.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 29).

Mechanisms governing avulsions in transient landscapes : analysis of the May 2006 Suncook River avulsion in Epsom, New Hampshire

Mon, 01 Jan 2007 00:00:00 GMT

Mechanisms governing avulsions in transient landscapes : analysis of the May 2006 Suncook River avulsion in Epsom, New Hampshire Perignon, Mariela C Avulsions, or rapid changes in the location of a river, usually occur in environments such as deltas, floodplains, and alluvial fans where net-deposition can raise the bed of the river above its floodplain. Avulsions are less frequent in transient landscapes, such as New England, where topography and hydrography are still responding to recent glaciation. One of these rare avulsions occurred during a 100-year flood on the Suncook River, Epsom, NH, between May 14 and 15,2006. We studied the Suncook River event to develop a model for the drivers of avulsions in transient landscapes. We suggest that a strong substrate in the parent channel, such as bedrock or immobile boulders, can facilitate an avulsion by preventing incision and driving water overbank. Easily erodible substrates in the path of the new channel can also contribute to avulsions by allowing a knickpoint to migrate quickly upstream and create a channel with a more favorable slope during a single flood. Based on Slingerland and Smith's (2004) model, we also propose that a low water-surface slope in the parent channel could be a direct driver for avulsions. In the Suncook River, this low water-surface slope was created in the backwater of a small mill dam in the parent channel. A 200-year flood that occurred in the Suncook River in 1936 did not create an avulsion. We suggest that ice floats could have damaged the dam and increased the water-surface slope of the parent channel, making an avulsion less favorable and reducing the depth of water flowing overbank. The topography in the path of the 2006 avulsion, which was lowered by activity in a sand pit starting in the 1960s, probably prevented water from finding a new path. We believe that these anthropogenic modifications directly contributed to the occurrence of the May 2006 avulsion in the Suncook River. These conditions are common throughout New England, and could increase the risk of avulsions in the region. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2007.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 60-66).

Local and expert knowledge in experienced mining communities : the case of a proposed uranium mine in Crownpoint

Mon, 01 Jan 2007 00:00:00 GMT

Local and expert knowledge in experienced mining communities : the case of a proposed uranium mine in Crownpoint Roth, Cassandra (Cassandra B.) Public access to science is an essential environmental justice component of any mining development. Both limited public access to professional scientific knowledge and little acknowledgment by professionals of the contributions of local knowledge hinder discussion of proposed mines. A proposed uranium mine in Crownpoint, New Mexico, a predominantly Navajo community, presents a case for studying the role of expert and local knowledge in the individual's perception of the risks and benefits associated with the mine. Interviews, supplemented with numerous Nuclear Regulatory Commission documents and other articles of the public record, were used to understand how people developed their personal understanding of the trade-offs of mining uranium in their town. This research reveals that family experiences and personal observations are correlated with individual perception of risk, but the perception of uncertainty is related the group of experts available to the individual. The results suggest that individuals in such communities should have access to a range of experts and that local knowledge and experiences should be taken into account when journalists, industry representatives and government officials translate expert knowledge for public consumption. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2007.; Thesis: S.B., Massachusetts Institute of Technology, Department of Urban Studies and Planning, 2007.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 51-53).

An analysis of a continuum X-ray Diffraction/Fluorescence instrument

Mon, 01 Jan 2007 00:00:00 GMT

An analysis of a continuum X-ray Diffraction/Fluorescence instrument Murphy, Caitlin Anne Scientists at NASA's Goddard Space Flight Center have developed a Combined X-ray Diffraction/Fluorescence (CXRDF) instrument. CXRDF performs simultaneous chemical and structural analysis of an unprepared sample, making it ideal for planetary mineral identification. In an effort to analyze the effectiveness of CXRDF, samples were chosen from a list of minerals that are important in the debate about the origin of the outcrops at Meridiani Planum on Mars. These samples were run on both CXRDF and a laboratory X-ray diffractometer. The datasets were compared, looking at peak identification, d-spacing resolution, and whether the instruments could definitively identify each sample. CXRDF successfully measured the d-spacings for each mineral, and the chemical analysis data were very valuable. However, for CXRDF to be able to definitively identify minerals, its d-spacing range and resolution will need to be improved, in addition to its data analysis software. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2007.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 40-41).

The influence of the Atlantic Meridional Mode on the frequency, duration, and intensity of tropical North Atlantic cyclones

Mon, 01 Jan 2007 00:00:00 GMT

The influence of the Atlantic Meridional Mode on the frequency, duration, and intensity of tropical North Atlantic cyclones Loyd, Nicholas (Nicholas W.) This paper describes the Atlantic Meridional Mode (AMM) and its influence on tropical storm activity in the North Atlantic Basin. The Atlantic Meridional Mode is the oscillating sea- surface temperature (SST) gradient anomaly between the Northern Hemisphere (NH) and Southern Hemisphere (SH) portions of the Tropical Atlantic Ocean (TAO). Synthetic data generated from computer simulations as well as actual reanalysis data from North Atlantic Basin tropical storms was examined. A moderate correlation exists between increased (decreased) North Atlantic tropical storm activity and the high (low) phase of the AMM. The AMM correlates more strongly with the duration and intensity of tropical storms than the frequency. Increased understanding about the AMM and its affects on tropical storm activity will lead to improved forecasting of tropical systems, which affect many human lives each year. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2007.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 31).

Stable isotope probing of hyperthermophilic filamentous microbial communities in Octopus Spring, Yellowstone National Park

Mon, 01 Jan 2007 00:00:00 GMT

Stable isotope probing of hyperthermophilic filamentous microbial communities in Octopus Spring, Yellowstone National Park Dibbell, Augusta K Stabe isotope probe (SIP) incubation studies were performed using ¹³C-labeled carbon substrates on hyperthermophilic filamentous streamer communities inhabiting Octopus Spring in Yellowstone National Park. Biomass was removed from the outflow stream and incubated at near-in situ conditions with labeled bicarbonate, formate, or acetate. Lipids from the biomass were extracted and analyzed using gas chromatography-mass spectroscopy (GC-MS) and gas chromatography-isotope ratio monitoring-mass spectroscopy(GC-IRMS). We observed incorporation of ¹³C-labeled acetate into the total biomass, archaeal lipids, and a small number of bacterial lipids, but no incorporation of labeled formate or bicarbonate. During 67 hours of incubation, 0.060 [mu]g of labeled acetate was incorporated by the archaeal and bacterial community. The lack of acetate incorporation by most bacteria, or formate and bicarbonate incorporation by any community member may reflect rates of carbon turnover, the carbon acquisition pathway used, or inhibition under experimental conditions, Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2007.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 49-50).

Lability of dissolved organic carbon in Arctic rivers on the North Slope of Alaska

Mon, 01 Jan 2007 00:00:00 GMT

Lability of dissolved organic carbon in Arctic rivers on the North Slope of Alaska Frazer, Breton B Rivers are an important pathway of organic carbon-mobilization in the arctic, and their influence is projected to grow as precipitation and soil temperatures increase in response to highlatitude warming. This study addresses the bioactivity of arctic riverine dissolved organic carbon (DOC) in three North Slope Alaskan rivers: the Kuparuk, the Colville, and the Sagavanirktok. While lability experiments have previously been conducted during late summer discharge on arctic rivers, none have analyzed the early hydrograph spring-melt peak DOC. During the summer of 2006, water samples were taken from significant periods of the hydrograph (upswing, peak, downswing, and quasi-stable summer) of the three rivers for DOC lability experiments. DOC from spring melt discharge proved to be highly labile and therefore dynamically different from summer DOC. Over a three-month sample incubation period, these samples lost up to 40 and 33 percent of their DOC (with and without added nutrients, respectively) while samples taken later in summer lost merely 9 and 5 percent. As spring melt contributes half of the total annual discharge and DOC flux of winter-freezing rivers, a significant portion of annual arctic DOC is labile and is therefore a large input of bioactive organic DOC to the Arctic Ocean carbon cycle. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2007.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 16-18).

Oxygen isotope systematics of nitrification

Mon, 01 Jan 2007 00:00:00 GMT

Oxygen isotope systematics of nitrification Buchwald, Carolyn During nitrification there is an exchange of oxygen atoms between water and nitrite, causing the [delta]¹⁸O of nitrate produced by nitrification to be closer to the [delta]¹⁸O of water than expected. A series of lab and field experiments were set up in order to quantify the exchange, and then calculate the [delta]¹⁸O of nitrate with these values. The lab experiments tested the exchange in ammonia oxidation, using ammonia oxidizing bacteria, Nitrosomonas sp. C113a and Nitrococcus oceani, and nitrite oxidation using cultures of the nitrite oxidizing bacterium, Nitrosococcus mobilis. The exchange value in the ammonia oxidation experiments could not be calculated because of unexpected complications in the analysis in the [delta]¹⁸O of nitrite. Although we weren't able to obtain a confident value for the exchange we were able to find a way to correct the [delta]¹⁸O of nitrite, for blank and exchange that affects the sample [delta]¹⁸O value for nitrite measured by the mass spectrometer. The exchange in the nitrite oxidation experiment could not be measured because there was full abiotic exchange in the bottle preventing us from calculating biotic exchange. A control experiment was successful in eliminating this exchange by adjusting the pH to a value higher than 8 prior to inoculation of the media during the experiment. In a future nitrite oxidation experiment this change in experimental design would make it possible to measure the exchange during nitrite oxidation. The experiments were a good step toward developing the best way to measure microbially-catalyzed exchange, and hopefully this value can be quantified in future analysis. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2007.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 39-41).

Refinements and improvements to a phenomenological model for the jet opening angles of gamma-ray bursts

Sun, 01 Jan 2006 00:00:00 GMT

Refinements and improvements to a phenomenological model for the jet opening angles of gamma-ray bursts Tsitkin, Yelena Long duration gamma-ray bursts (GRBs) are thought to originate from the core collapse of massive, rapidly rotating stars - events called "hypernovae." In this thesis, we improve upon a phenomenological model to determine [theta], the jet opening angle of GRBs. We assume that hypernova progenitors are massive stars in binary systems. We calculate [theta] by equating two expressions for the probability of a given GRB being detected - one based on the geometry of the beaming model and the other based on the observed and expected rates of long duration GRBs. These expressions give [theta] as a function of several key physical parameters. We estimate these parameters, perform a Monte Carlo simulation, and obtain the most probable value of [theta] for both single and double jet GRB models. In contrast to previous work, we allow the minimum mass of star-forming galaxies to vary between 10⁶Mo and 10⁷Mo, and we calculate the galactic number density separately for three subtypes of spiral galaxies. For single jet and double jet models, we find that [theta] = 2.8+³.²-¹.². deg and [theta] = 1.9+².²-⁰.⁸. deg respectively. These results are somewhat lower than the results obtained in the earlier stages of this project [15, 16], but are in agreement with values inferred from the observed properties of GRBs [4]. Our results therefore support the assumption that massive binary stars are the progenitors of hypernovae that produce long-duration GRBs. Thesis: S.B. in Planetary Science and Astronomy, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 33-35).

Lower Charles River bathymetry : 108 years of fresh water

Sun, 01 Jan 2017 00:00:00 GMT

Lower Charles River bathymetry : 108 years of fresh water Yoder, Madonna K The Lower Charles River has been a heavily utilized urban river that runs between Cambridge and Boston in Massachusetts. The recreational usage of the river is dependent on adequate water depths and there have been no definitive prior studies on the sedimentation rate of the Lower Charles River. The river transitioned from tidal to a freshwater basin in 1908 and the study area for historical comparisons was from the old Charles River Dam to the Boston University Bridge. This study surveyed the river, digitized three prior surveys that spanned 114 years, calculated volumes and depth distributions for each survey, and estimated sedimentation rates from fits to the volumes over time. The average sedimentation rate is estimated as 5-10 mm/year, which implies 1.8-3.5 feet sedimentation since 1908. Sedimentation rates and distributions are necessary to develop comprehensive management plans for the river. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 22).

A coupled atmosphere-ocean model of thermohaline circulation, including wind-driven gyre circulation with an analytical solution

Sun, 01 Jan 2006 00:00:00 GMT

A coupled atmosphere-ocean model of thermohaline circulation, including wind-driven gyre circulation with an analytical solution Olson, Elise Marie Black A parameter representing circulation due to wind forcing is added to the thermohaline circulation model of Marotzke (1996). The model consists of four boxes and is governed by a system of two differential equations governing the temperature and salinity differences between high latitude ocean and low latitude ocean boxes. The modified model is solved numerically for equilibrium solutions, and then solved analytically by the method of Krasovskiy and Stone (1998). At the maximum strength of wind-forced circulation studied, v = 5 x 10-¹¹ s-¹, a stable thermal mode equilibrium temperature difference of 25 K is calculated. Once v reaches a critical value, which is within the range of physically reasonable values, the stable haline mode equlibrium and unstable thermal mode equilibrium are no longer observed. It is concluded that strong wind-forced circulation suppresses the thermal mode equilibrium, but that more research is necessary to determine the degree to which this effect is present in the real world. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.; Cataloged from PDF version of thesis. "February 2006."; Includes bibliographical references (page 35).

Photometric and spectral analysis of the distribution of crystalline and amorphous ices on Enceladus as seen by Cassini

Sun, 01 Jan 2006 00:00:00 GMT

Photometric and spectral analysis of the distribution of crystalline and amorphous ices on Enceladus as seen by Cassini Newman, Sarah F Photometric and Spectral analysis of data from the Cassini Visual and Infrared Mapping Spectrometer (VIMS) has yielded intriguing findings regarding the properties and composition of the surface of Saturn's satellite Enceladus. Spectral cubes, which contain both spatial and spectral information, were obtained of this satellite with a wavelength distribution in the infrared far more extensive than from any previous observations and at much higher resolution. Using these cubes, we have discovered a distribution of amorphous and crystalline ices on the southern pole of Enceladus, indicating intense ion bombardment in those latitudes and recent geological activity at the "tiger stripe" cracks. Using a composite mosaic of the satellite, we map this distribution of ices according to a "crystallinity factor" and consider investigation of the time scale of the geologic activity based on amorphization rates in the outer solar system. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.; Cataloged from PDF version of thesis. Pages 26 to 30 missing from original thesis.; Includes bibliographical references (pages 30-31).

Comets in the near-Earth object population

Sun, 01 Jan 2006 00:00:00 GMT

Comets in the near-Earth object population DeMeo, Francesca E Because the lifespan of near-Earth objects (NEOs) is shorter than the age of the solar system, these objects originated elsewhere and they must have a source of re-supply. We seek to determine what fraction of the NEO population consists of dormant or extinct comets. We identify comet candidates among NEOs using three criteria: the Jovian Tisserand parameter Tj < 3, comet nucleus-like spectral parameters (generally linear spectra which correspond to C, D, or P taxonomic types), and low (<0.075) albedos. Out of 31 objects we sample having Tj < 3, we find 17 objects or approximately 55% also satisfy these comet candidate criteria. Bias corrected discovery statistics (Stuart 2003, Ph.D. thesis; Stuart & Binzel 2004, Icarus 170, 295) estimate 30% of the entire NEO population resides in orbits having a value of Tj < 3. Combining these two factors suggests that approximately 16% of the total NEO population has both dynamical and physical properties consistent with a cometary origin. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.; Cataloged from PDF version of thesis. Original thesis missing pages 14, 15, 17, 30 and 31.; Includes bibliographical references (pages 31-32).

A preliminary analysis of the lipid contents of a biofilm from a Yellowstone hydrothermal pool

Sat, 01 Jan 2005 00:00:00 GMT

A preliminary analysis of the lipid contents of a biofilm from a Yellowstone hydrothermal pool Hays, Lindsay Elizabeth The hot springs at Yellowstone National Park, such as Obsidian Pool, have been extensively studied as a source for previously unidentified microorganisms. Most of the previous studies focused on the genomic diversity of these environments, but recent interest in environmental samples for the study of lipid biomarkers has extended to these hot springs as well. In this preliminary study of Obsidian Pool, I used a modified Bligh and Dyer extraction process to create a total lipid extract (TLE), which was then further separated and processed by an acetone precipitation, mild alkaline methanolysis and column chromatography to isolate different fractions of the TLE. Compounds were then identified by gas chromatography-mass spectrometry (GCMS). The mild alkaline methanolysis allowed for the identification of decanoic acid methyl ester, a fatty acid methyl ester. From the column chromatography, only the saturated hydrocarbon fraction yielded interesting compounds; these were a series of n-alkanes (n-C₁₇, n-C₂₀, and n-C₂₃ - n-C₃₁), two branched alkanes (5-methyloctodecane and 4-methylheptadecane), an isoprenoid (dibiphytane), a series of branched aliphatic alkanes with a quaternary substituted carbon atom (5,5 diethylalkanes), and a variety of hopanoids and steroids. These compounds indicate a strong community of bacterial and archaeal species in Obsidian pool. Some compounds that were indicative of eukarya were also identified, although a more in-depth study is necessary to determine whether these signals were from the pool or from external inputs. The lipids identified in this study indicate that the genomic diversity established by previous studies is reflected in the lipid diversity of Obsidian Pool. However, more study is required to fully categorize the lipids in the pool. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2005.; Cataloged from PDF version of thesis. Original thesis missing page 15.; Includes bibliographical references (pages 28-30).

Spin directions of asteroids : lightcurve analysis of Koronis family members 158 Koronis and 720 Bohlinia

Mon, 01 Jan 2001 00:00:00 GMT

Spin directions of asteroids : lightcurve analysis of Koronis family members 158 Koronis and 720 Bohlinia Crespo da Silva, Lucy (Lucy d'Escoffier) Clusters of asteroids within the main-belt are referred to as dynamical families because they are believed to have originated as the result of collisional destructions of large parent bodies. Family members are the remnants of the parent body break-up and often retain some of the parent body's original rotational information. Previous studies have indicated that the Koronis dynamical family may have been relatively recently formed due to the non-random nature of the orientation of its members spin vectors. This project was undertaken to contribute to the rotational data on Koronis family members in order to better understand the unusual properties observed. The goal of this project was to determine the directions of spin of Koronis family members 158 Koronis and 720 Bohlinia. Observations were made at the MIT Wallace Astrophysical Observatory in Westford, Massachusetts during 1999. Both of the targets were determined to have a retrograde sense of rotation, which is in agreement with the previously known sense of rotation of Koronis family member 243 Ida. In addition, the synodic period of 158 Koronis was confirmed by these observations, and a new value for the sidereal period of 720 Bohlinia was found to be 8.920 ± 0.005 hours. During the course of the observations, an uncataloged asteroid was discovered and has since been assigned the designation 1999 QQ2 by the IAU Minor Planet Center. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, February 2001.; "May 2000." Cataloged from PDF version of thesis.; Includes bibliographical references (page 43).

Analysis of biomarker candidates from plant lipid inputs into Galapagos lacustrine sediments

Thu, 01 Jan 2004 00:00:00 GMT

Analysis of biomarker candidates from plant lipid inputs into Galapagos lacustrine sediments Ricke, Katharine (Katharine Leigh) Paleoclimatological investigations into past precipitation and temperature patterns in regions of the tropical Pacific may be the key to resolving scientific disputes about the effects of global warming on the magnitude and frequency of the El Niño/Southern Oscillation (ENSO) phenomenon. Plant lipids identified in the sediment record of lakes in regions of high ENSO activity can act as biomarkers to reconstruct past precipitation patterns by measuring the D/H ratios preserved in these compounds to observe the local climate changes with global temperature variations. Twelve plant species and two sediment samples from in and around El Junco lake catchmernt on Sari Cristobal in the Galapagos Islands were solvent extracted, identified and quantified using gas chromatography arid mass spectrometry. The analysis revealed evidence for significant aquatic and terrestrial vascular plant inputs to lake sediments. High concentrations of unsaturated C₁₆ and C₁₈ fatty acids were found in all plant samples, but these compounds appear to be degraded significantly in the sediment record. n-Alkane distributions suggest a strong hydrocarbon contribution from submerged and floating plants. Additionally, a terrestrial biomarker, fernene, was identified. The information in this study should be a helpful guide for further biomarker identification efforts at the El Junco lake and in other tropical crater lakes. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2004.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 55-57).

Analysis of shock propagation in the magnetosheath

Wed, 01 Jan 2003 00:00:00 GMT

Analysis of shock propagation in the magnetosheath Wallace, Aletta M. J. (Aletta Margaret Jensen) Four interplanetary shock waves and disturbances are analyzed. Data recorded by multiple spacecraft are compared in order to determine how the speed of these events is modified when they cross Earth's bow shock into the magnetosheath. To accomplish this, it was necessary to find shocks that were seen by spacecraft both in the solar wind and inside the magnetosheath. Using a velocity coplanarity and a Rankine-Hugoniot methods of shock normal analysis, the speeds of these events in the solar wind were calculated. The time of their arrival at a spacecraft in the magnetosheath was determined. The predicted arrival time, assuming a constant shock speed from the spacecraft in the solar wind to the spacecraft in the magnetosheath is then compared to the actual arrival time. The resulting data support the conclusion that there is no change in the speed of the shock as it propagates through the magnetosheath. Thesis: S.B. in Planetary Science and Astronomy, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2003.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 25-26).

Finite element comparison for a geologically motivated benchmark

Wed, 01 Jan 2003 00:00:00 GMT

Finite element comparison for a geologically motivated benchmark Peters, Teresa Baker, 1981- Geologic deformation in three dimensions can be modeled using finite element analysis. In choosing the elements used to solve a model it is important to consider the accuracy of the solution and the computational intensity. The results for models using six element types and six element side lengths are compared for the accuracy of the displacements calculated by the solution and the number of nodes required, as a proxy for computational intensity. Elements that allow higher order solutions are much more accurate than elements that only allow linear interpolation of the stresses and displacements between nodes; however the number of nodes required is five times greater. Free-form meshes do not significantly improve the performance of tetrahedra for the models tested, but could be accurate enough to model curved problem geometries. Comparisons for other models, such as a thrust fault, can be made using a twodimensional simplification of the three-dimensional problem. If three-dimensional comparisons are required it is important to choose a model that has an analytical solution. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2003.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 22).

The role of eddies in buoyancy flux

Mon, 01 Jan 2001 00:00:00 GMT

The role of eddies in buoyancy flux Ring, Michael J., 1979- This thesis explores the role of eddies in determining the stratification of the ocean through a laboratory experiment. The experiment uses a dual-tank apparatus, with a smaller tank sitting inside the larger tank. Both tanks sit on a rotating turntable, which simulates the rotation of Earth. During the experiment, salty water is pumped from the outer tank through small holes in the base of the inner tank, which is initially filled with fresh water. The evolution of the dense fluid in the inner tank is observed, with particular regard to the number of eddies that form. These observations are checked against theoretical predictions, derived from analysis of buoyancy flux, for the number of eddies expected to form. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2001.; Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2001.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 35).

A method for the determination and distribution of the mill room costs of the Converse Rubber Shoe Company

Thu, 01 Jan 1920 00:00:00 GMT

A method for the determination and distribution of the mill room costs of the Converse Rubber Shoe Company White, Kenneth Blake; Warriner, R. Peverell Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Business and Engineering Administration, 1920.

Buckling of reinforced rings

Wed, 01 Jan 1964 00:00:00 GMT

Buckling of reinforced rings De Sá Freitas, Elcio Thesis (Nav.E)--Massachusetts Institute of Technology, Dept. of Naval Architecture and Marine Engineering, 1964.; Includes bibliographical references (leaf 73).

Hillslope evolution in response to lateral base level migration

Fri, 01 Jan 2010 00:00:00 GMT

Hillslope evolution in response to lateral base level migration Hamon, Jennifer L. Hillslopes evolve in response to base level change, sediment production, and sediment transport. Many previous studies have focused on hillslopes undergoing vertical base level migration due to tectonic forcing and bedrock incision. Many geomorphic features, however, are characterized by lateral hillslope retreat and have not been adequately studied. Here I adapt a theory of linear diffusive hillslope evolution to relate the velocity of lateral hillslope retreat to the steady-state hillslope form. A case study in a Florida sapping network, in which headward migration of seepage faces in a sandy soil sets the base level for the surrounding hillslopes, provides numerous opportunities to test the analytical model by direct measurement. Measurements of hillslopes in the Florida sapping network found quantitative agreement between the predicted and observed hillslope morphology. An expected relationship between geometric drainage area and channel growth velocity was not borne out in the data, but the distribution of measured v/K ratios is consistent with what I expect based on my preferential sampling of slow-moving gently-sloped heads. Several explanations are given to explain why the expected relationship with drainage area is not observed, and suggestions for future work based on these findings is offered. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2010.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 32-33).

Measuring transit timing variations of exoplanets using small telescopes

Fri, 01 Jan 2010 00:00:00 GMT

Measuring transit timing variations of exoplanets using small telescopes Morley, Caroline V Transits of exoplanets were observed from June 2009 through January 2010. Six transit light curves are presented in this paper for three planets: WASP-10b, WASP- 11/HAT-P-10b, and TrES-3. Measurements of the planetary radii, semi-major axis, transit duration, and period confirmed literature values to within two sigma. Transit timing variations were not observed in these systems, but calculations show that it would be possible to measure transit timing variations induced by large exomoons (greater than about 6 Earth masses) in the WASP-11/HAT-P-10b system. Challenges of exoplanet observation from small telescopes are discussed. It was determined that overall, transit measurements of many exoplanets using small telescopes can be successful and scientifically useful. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2010.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 57-58).

Stable isotope and organic biomarker analysis of the late Proterozoic Coppercap formation in the MacKenzie Mountains

Fri, 01 Jan 2010 00:00:00 GMT

Stable isotope and organic biomarker analysis of the late Proterozoic Coppercap formation in the MacKenzie Mountains Thomas, Katherine S., S.M. Massachusetts Institute of Technology Sulfur and carbon stable isotope ratios and organic biomarker abundance were performed on drill core samples from the Coppercap Formation of the Coates Lake Group in the Windermere Supergroup of the MacKenzie Mountains to reconstruct an environmental condition proceeding the first Neoproterozoic Snowball Earth event. The Coppercap Formation directly underlies the Rapitan Group, Sturtian glacigenic deposits, and represents a depositional environment existing directly before the Cryogenian glacial episodes. Based on aryl isoprenoids, n-propyl cholestane, isopropyl cholestane, total organic carbon, carbonate mineral analysis, [delta]34S from pyrite, [delta]13Corganic and [delta]13Ccarbonate values, environmental conditions of the Coppercap Formation were reconstructed. The Coppercap Formation was found to be a shallow euxinic marine basin with purple and green sulfur bacteria microbial mats. This suggest persistent hydrogen sulfide rich waters in the shallow photic zone persisted until the Sturtian. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2010.; Cataloged from PDF version of thesis.; Includes bibliographical references (unnumbered pages 56-59).

QX Pup : the fascinating yolk of the Rotten Egg Nebula

Tue, 01 Jan 2013 00:00:00 GMT

QX Pup : the fascinating yolk of the Rotten Egg Nebula Berry, Kristin L QX Pup is a known Mira variable at the core of the Rotten Egg Nebula that has not been studied in detail since its discovery in 1983. In this study, four years of photometric data in V and I and two years of photometric data in R and B are analyzed. A period of T = 535.4 ± 8 days, and a magnitude drop of [Delta]mI , = 2.2 ± 0.69 are measured in I, and and phase shifts between the the other three filters and I are determined to be [o]R = 6 ± 40 days, [o]B = 66 ± 64 days, #, [o]v = 16 ± 86 days. These results are used to speculate about the possibility of a light-echo off the Rotten Egg Nebula and the conditions on Earth-like planets around Mira variables. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2013.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 31-32).

Comparison of PSF fitting methods for determining centroids of stars

Tue, 01 Jan 2013 00:00:00 GMT

Comparison of PSF fitting methods for determining centroids of stars Gibson, Stephanie, S.B. Massachusetts Institute of Technology This paper shows a comparison of four fitting models used in order to calculate the centroids for twelve stars. The offsets for each coordinate are calculated with respect to the mean of the coordinates for varying aperture sizes. The computed offsets are then compared to determine if there was any effect from the magnitude of the star or the star's position on the CCD chip. An appropriate aperture size of 12 pixels is chosen in order to compare each method. It is determined that a magnitude effect exists, though it is very small and results in an approximate difference between residuals of between 0.02 and 0.04 pixels, which for most methods is within the fitting error. For the position on the chip effect, the vectors of the x and y residuals are produced in vector plots in order to demonstrate the directional tendency each fitting method had dependent on chip position. Each model has some dependency on position on the CCD chip, with 0.033 pixels as the largest variation between models. Therefore, for accuracy less than 0.033 pixels any of these models can be used for fitting a PSF to a star. However, if greater accuracy is needed more steps need to be taken in order to determine the best PSF fit. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2013.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 45).

Feasibility of using cloud top altimetry for estimating tropical cyclone intensity estimation

Sun, 01 Jan 2006 00:00:00 GMT

Feasibility of using cloud top altimetry for estimating tropical cyclone intensity estimation Wong, Valerie (Valerie Wan Chi) This project explores whether cloud top altimetry can be used as an accurate and reliable means of estimating the intensity of tropical cyclones. Professor Kerry A. Emanuel developed the theory that is under investigation. His theory aims to calculate the peak surface wind speed in hurricanes using only three parameters, all of which can be collected from satellite imagery: cloud top height, sea surface temperature and cloud top temperature. Cloud top heights for selected hurricanes were obtained from the ICESat, and points were identified where the ICESat may have traversed the hurricanes. These points were compared with IR images to confirm the intersection of the ICESat track and the hurricane tracks. Out of 18 hurricanes examined, four provided feasible points to test this new technique. Two of these points were from hurricanes that were at the end stage of their life cycle; these two data points were discarded. Data from the two usable data points were compared to the recorded wind speeds from Unisys. It seems that the new method is overestimating the maximum surface wind speed by less than 10%. Two data points are insufficient for conclusively validating this technique. However, this project has established a viable method for gathering and analyzing altimetry data, providing a basis for further testing of the theory. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.; Cataloged from PDF version of thesis. Some pages in the original thesis contain text that runs off the edge of the page.; Includes bibliographical references (pages 36-37).

Analyzing the large-scale curvature of interplanetary shocks

Sun, 01 Jan 2006 00:00:00 GMT

Analyzing the large-scale curvature of interplanetary shocks Vogt, Marissa Farland The 3-dimensional structure of interplanetary shock surfaces are analyzed using observations from the Wind and ACE spacecraft. Events seen by both spacecraft were selected from the available data and used to calculate the radius of curvature R, of the shock surface. The surface structure was examined within the ecliptic plane, and evidence of large-scale curvature was seen when the spacecraft separation was sufficiently large. A simulation was run to test the effects of small errors in the shock normal, and showed that these errors could affect R, calculations at small separation. The radius of curvature was studied as a function of shock strength to look for evidence of ripples on the shock surface, though no correlation was found. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.; Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2006.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 36-37).

Rotationally resolved visible spectroscopy of the Asteroid 1 Ceres

Tue, 01 Jan 2013 00:00:00 GMT

Rotationally resolved visible spectroscopy of the Asteroid 1 Ceres Henderson, Phoebe J This thesis was designed to make spectroscopic measurements of Ceres within the visible spectrum, specifically within the wavelength range of 6000 and 7000 Angstroms. The asteroid was observed for 6 nights, for lengths of time varying from 3 to 7.5 hours. The main goal was to support/refute the previous findings about absorption features within the wavelength range being observed. Additionally, this thesis was designed to determine the rotational variability of minerals on Ceres. In order to determine the asteroid's variablity, the rotational period of Ceres was divided into eight phases, and average spectra were determined for each phase. The results show that there is a weak rotational variability of the feature between 6200 and 6400 Angstroms. The feature varies over the surface of Ceres by 2.5% with a mean error of 1.6%. There have been previous reports of absorption features on asteroids between 6000 and 6500 Angstroms, which have been associated with ferric Fe absorptions in Fe alteration minerals. Examples of such minerals include goethite and iron oxide hematite. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2013.; "June 2013." Cataloged from PDF version of thesis.; Includes bibliographical references (pages 23-24).

Killer asteroids : feasibility of using the IRTF to track near-earth objects

Sun, 01 Jan 2006 00:00:00 GMT

Killer asteroids : feasibility of using the IRTF to track near-earth objects Shah, Kaya (Kaya Y.) The possibility of an asteroid or comet impact necessitates the tracking and cataloging of all such objects which could potentially impact Earth. Currently, no comprehensive catalog of Near Earth Objects (NEOs) exists which contains information on the physical properties of the objects. Spectroscopic observation of NEOs must be carried out in an efficient and timely manner in order to determine the physical properties of NEOs for this catalog. The cumulative fractions of objects visible at certain magnitudes were examined and compared for the NEOs discovered in 2005 at discovery, those at the first quarter moon following discovery, and all known NEOs in 1, 3, 5, and 10 year forecasted surveys to determine the best combination of Infrared Telescope Facility (IRTF) instrumentation, telescope observation time, and survey length. This thesis finds that the IRTF instrumentation should be improved to at least 19.5 to spectroscopically observe 57% of the objects discovered in 2005. Furthermore, spectroscopic observation of the objects should not occur at the first quarter moon immediately after discovery, as is currently the case, because as much as ~15% of the objects discovered in 2005 cannot be observed at this time. As survey length is increased, the fraction of objects that can be observed at the IRTF's current limiting magnitude also increase; thus it is best to conduct the survey as long as possible. Additionally, spectroscopic observation of the objects should be carried out every 7 days in order to gather the most information. Lastly, it is best to spectroscopically observe the objects within 7 days of discovery because the objects are generally discovered when they are at their closest possible approach to the Earth. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 31).

Characterizing fault structure and general morphology of the Tensleep Sandstone of Teapot Dome, Wyoming as it relates to industrial carbon sequestration

Sun, 01 Jan 2006 00:00:00 GMT

Characterizing fault structure and general morphology of the Tensleep Sandstone of Teapot Dome, Wyoming as it relates to industrial carbon sequestration Michalak, Melanie J Consistent data demonstrates a rise in global atmospheric concentrations of carbon, in the form of carbon dioxide. A large portion of the current atmospheric concentration is due to emissions from the burning of fossil fuels, which humans use for energy consumption. Many experts believe that of all the mechanisms in which carbon dioxide emissions can be mitigated, sequestering carbon dioxide, specifically in geologic reservoirs, is among the most promising of all approaches. This paper examines a fault structure in the specific geologic reservoir known as NPR-3, or the Teapot Dome oilfield. Using seismic modeling and subsurface modeling software packages to interpret seismic data of the region, geologic features and faults are mapped. These maps provide valuable characterization information useful to an overall evaluation of the effectiveness of geological storage of carbon sequestration in the Teapot Dome site. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 17).

Sizing the X-ray spectral resolution limits of the REgolith X-ray Imaging Spectrometer (REXIS) instrument at Asteroid 1999RQ36

Tue, 01 Jan 2013 00:00:00 GMT

Sizing the X-ray spectral resolution limits of the REgolith X-ray Imaging Spectrometer (REXIS) instrument at Asteroid 1999RQ36 Megyery, Suzanna The REgolith X-ray Imaging Spectrometer (REXIS), a Charge-Coupled Device (CCD)-based coded aperture soft X-ray (0.3-7.5 keV) telescope for remote geochemical X-ray Fluorescence (XRF) spectrometry, will be flying on board the Origins Spectral Interpretations Resource Identification Security Regolith Explorer (OSIRIS-REx) asteroid sample return mission that will be visiting the asteroid 1999 RQ36 and sending a sample back to Earth. REXIS will detect elemental XRF lines and produce a histogram of results as the spacecraft orbits the asteroid as well as produce a global map of elemental abundance ratios. The accuracy requirement for measuring the global ratios of elements and the spectral resolution requirement for discriminating unique XRF lines from each other have been set in place. The correct interpretation of X-ray measurements from the surface of 1999 RQ36 is limited by properties that are intrinsic to the CCD detector, CCID-41, that has been chosen for REXIS. This thesis study outlines student experimentation and results that were conducted on the CCID-41 detector to gauge the intrinsic detector noise as a function of detector temperature. Further, the widening of spectral lines on the resultant histogram was also equated as a function of detector temperature. Members of the REXIS Team built a spectral resolution model to investigate both the widening of spectral lines as a function of detector temperature and the accuracy of the measurement of elemental abundance line ratios as a function of detector temperature. Data from the student laboratory experimentation suggested that the detector temperature remain at or below -75°C to minimize intrinsic noise properties. Data from the computational analyses of the spectral resolution model suggest consistent results that the detector temperature remains at or below -55°C to remain within the established REXIS requirements. The combination of these three results leads to the author's recommendation that a detector temperature requirement be set that the temperature of the CCD detector onboard REXIS shall not exceed -55°C and that a detector temperature goal be set that the temperature of the CCD detector shall not exceed -75°C. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2013.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 64-68).

Active deformation of the Shargyn Basin, a transpressional strike-slip intersection in western Mongolia

Tue, 01 Jan 2013 00:00:00 GMT

Active deformation of the Shargyn Basin, a transpressional strike-slip intersection in western Mongolia Thompson, Thomas Ben Intraplate faulting in central Asia is a major component of the Indo-Eurasian collision. The kinematics and mechanisms of intraplate deformation are important in understanding broad active tectonic patterns, reconstructing past tectonics, analyzing seismic hazard and identifying potential resources. We examine the fault kinematics surrounding the 150 km wide Shargyn Basin at the intersection of the left-lateral transpressional Gobi-Altai fault system and the right-lateral transpressional Altai fault system. The studies were performed using satellite data and targeted field transects. The results suggest the Shargyn basin is formed by a compressional stepover, an uplifted wedge from the intersecting strike-slip systems and many strike-slip terminating thrust splays. Furthermore, local foliation is almost always fault parallel, pointing to the importance of pre-existing structural weaknesses in the development of active faults. This research demonstrates some of the potential kinematics for intraplate transpressional orogenies and emphasizes the importance of pre-existing crustal structure in the development of active faults. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2013.; "June 2013." Cataloged from PDF version of thesis.; Includes bibliographical references (pages 37-41).

A test for a see-saw oscillation between the Amazon and Congo basins using regional climate modeling

Sun, 01 Jan 2006 00:00:00 GMT

A test for a see-saw oscillation between the Amazon and Congo basins using regional climate modeling Ling, Christopher S. K The Amazon and Congo basins represent two of the three largest regions of rainfall found on the globe. Eltahir et al. (2004) have proposed the existence of a "see-saw" oscillation between these two basins, where a reduction of rainfall in one region is marked by an increase in the other. This inverse relationship has been observed both directly by Eltahir et al., using satellite data of regional rainfall (Simpson et al. 1988), and indirectly through changes in river flow measurements (Amarasekera et al. 1977) during the last century. However, little work has been done to study this see-saw effect through the use of climate models. Using a regional climate model (RegCM), the appearance of the oscillation was tested by converting rainforest area in one basin into two different land types, simulating drought-like climate conditions to induce additional rainfall in the other basin. In total, one control run and four land-modified runs were simulated for this experiment. The effects of these conditions were modeled over a one-year period (1980). It was found that in some cases, reduction of rainfall in one basin resulted in increased rainfall in small areas of the other; however, over the entirety of both basins, evidence of the see-saw hypothesis was not simulated. Several factors may have contributed to this result, including the limitations associated with using a regional model, as well as the initial conditions set for the five climate simulations. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 49-50).

Understanding the spatial distribution of the Southern Hemisphere near-surface westerlies and Its trends

Thu, 01 Jan 2015 00:00:00 GMT

Understanding the spatial distribution of the Southern Hemisphere near-surface westerlies and Its trends Hilgenbrink, Casey C In some experiments in which idealized general circulation models (GCMS) are used to study the tropospheric response to stratospheric perturbations, the tropospheric response is much stronger and longer-lived compared to observations (e.g., Polvani and Kushner 2002, Kushner and Polvani 2004). Chan and Plumb (2009) found that those experiments which exhibited particularly long tropospheric decorrelation times (and, by the fluctuation dissipation theorem, much stronger annular mode responses) were marked by bimodality in the distribution of the latitude of surface zonal-mean zonal winds. Here, ERA-Interim and NCEP/NCAR reanalysis data are used to establish if this bimodality exists in the Southern Hemisphere (SH) near-surface winds, which would predict the existence of an additional mode of tropospheric variability exhibiting stronger and longer-lived responses than what has previously been observed. Histograms of the latitudinal position of maximum near-surface zonal-mean zonal winds turn up no convincing evidence of jet bimodality, although they do reveal an interesting - but probably spurious trimodality in the NCEP/NCAR June-August 850-hPa distribution of jet latitude. A climatology of wintertime zonal winds reveals that there is a time-mean split jet over the South Pacific Ocean; furthermore, empirical orthogonal function analysis reveals that, over the South Pacific, the dominant mode of wintertime zonal wind variability is a splitting and un splitting of the jet. Ultimately, both the climatological split jet and its variability are determined not to be evidence of jet bimodality. The temporal trends in the distribution of near-surface jet latitude are also examined. Stratospheric ozone depletion has been implicated in surface circulation changes in the SH high latitudes; one of these changes has been a poleward shift of the jet in austral summer. In this thesis, it is found that a poleward shift of the December-February distribution of jet latitude has taken place from the pre-ozone-hole to ozone-hole eras, consistent with previous findings. The novel result is that there has also been a poleward shift of this distribution in May, which is consistent with a secondary maximum in ozone depletion near the tropopause in April-May as observed by other authors (Thompson et al. 2011), and would imply the occurrence of troposphere-stratosphere coupling in late fall. An in-depth investigation of these May zonal wind trends will be pursued in future work. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2015.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 62-63).

Complex lipids in microbial mats and stromatolites of Hamelin Pool, Shark Bay, Australia

Wed, 01 Jan 2014 00:00:00 GMT

Complex lipids in microbial mats and stromatolites of Hamelin Pool, Shark Bay, Australia Myers, Elise McKenna Stromatolites, columnar rock-like structures, are potentially some of the oldest, microbially mediated fossils visible in the rock record; if biogenesis is able to be confirmed for these ancient stromatolites, some being greater than 3 billion years old, these ancient stromatolites could be used to demonstrate the microbial community assemblages throughout ancient time. Hamelin Pool, Shark Bay, Australia is an ideal field site for this task, as stromtolites and modern microbial mats coexist and the microbial mats have been shown to contribute to the formation of the stromatolites. Comprehensive lipid biomarker profiles were determined in this study for non-lithified smooth, pustular, and colloform microbial mats, as well as for smooth and colloform stromatolites. Intact polar lipids, glycerol dialkyl glycerol tetraethers, and bacteriohopanepolyols were analyzed via liquid chromatography-mass spectrometry (LC-MS) coupled to a Quadropole Time-of-Flight (QTOF) mass spectrometer, while the previously studied fatty acids (Allen et al., 2010) were analyzed using gas chromatography-mass spectrometry (GC-MS) to prove consistent signatures. From the lipid profiles, sulfate-reducing bacteria and anoxygenic phototrophic bacteria and archaea could be inferred. The presence of the rare 3-methylhopanoids was discovered in a significant portion of the samples, which could add to the characterization of this molecule, which has only been concretely linked to oxygenic conditions for formation. In accordance with Allen et al. in 2010, 2-methyhopanoids were detected, as well as limited signals from higher (vascular) plants. While the lipid profiles for all sediment types were similar, there were some differences that are likely attributable to morphological differences. However, the overall similarities suggest microbial communities can be similar between non-lithified microbial mats and stromatolites. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2014.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 44-50).

Ice and the apparent variation of GPS station positions for Alaska

Thu, 01 Jan 2015 00:00:00 GMT

Ice and the apparent variation of GPS station positions for Alaska Kochanski, Kelly Anne Most GPS stations in Alaska show apparent seasonal variations on the order of one centimeter. The majority of these stations move downwards throughout the winter, a motion which is in phase with regional snowfall and has been attributed to hydrological loading (Fu et. al., 2012). The range of phases across the state, however, spans half the year and does not correlate with snow patterns. Six stations show discontinuous seasonal variations on the order of 1-10cm. After examining the geography and windspeed at these sites, we conclude that at least three of them will accumulate rime ice during the winter, and that this ice can cause apparent upwards motions of the stations. This hypothesis is supported by seasonal variations in the stations' multipath values, which indicate increased signal scattering during the winter. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2015.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 49-50).

First autonomous telescope at Wallace Observatory : impact and preliminary results

Thu, 01 Jan 2015 00:00:00 GMT

First autonomous telescope at Wallace Observatory : impact and preliminary results Kosiarek, Molly (Molly R.) The construction and characterization of an autonomous telescope began in Fall 2014 at the MIT George R. Wallace, Jr. Astrophysical Observatory. An 11-inch Cassegrain Telescope was assembled in a 10-foot Technical Innovations ProDome. This telescope, the Small AUtonomous Robotic Optical Nightwatcher (SAURON), has the potential to autonomously collect photometric images. Data were taken on T-And0-15785, an eclipsing binary star, in order to test and characterize the system. The out-of-ecliptic R magnitude of T-AndO-15785 was found to be 13.487 ± 0.016. The magnitude changes for the primary and secondary eclipses were found to be 0.72 ± 0.036 and 0.62 ± 0.031 R magnitudes respectively. The telescope, SAURON, is currently able to locate targets and collect data robotically with an observer monitoring from afar. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2015.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 75-76).

Variable star photometry in a secondary school curriculum

Thu, 01 Jan 2015 00:00:00 GMT

Variable star photometry in a secondary school curriculum O'Brien, Hollie M The author proved that photometry of variable stars can be performed by anyone using the shoestring budget of only a digital camera along with a laptop. Extrinsic variable star Algol was observed using a 14" telescope as well as CCD and had its light curve plotted. In direct comparison, V474 Mon was observed using only a low cost $200 digital camera. Armed with a laptop for data analysis, the author plotted its light curve. Lastly, the whole process of research astronomy was applied to a classroom final project setting. Future work includes expanding this thesis into a full semester long astronomy course for high school students. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2015.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 61-64).

A near-ultraviolet spectroscopic survey of B-type asteroids

Thu, 01 Jan 2015 00:00:00 GMT

A near-ultraviolet spectroscopic survey of B-type asteroids Peter, Ashley J This study aimed to evaluate the presence of spectral slope variations of B-type asteroids in the near-ultraviolet wavelength range and further compare variations to those found in the near-infrared (de Leon et al., 2012) and infrared (All-Lagoa et al., 2013). New observations of 19 B-type asteroids were obtained using the Telescopio Nazionale Galileo (TNG) and additional observations were collected on the William Herschel Telescope (WHT) and Isaac Newton Telescope (INT). After identifying appropriate solar analogs for spectral reduction, it was found that 1) not all asteroids are B-types as classified by the M4AST online tool (Popescu et al., 2012), and 2) spectral slope variations were present amongst the B-type asteroids. These spectral slope variations could not be traced to the use of certain solar analogs or differences in airmass during observations. Furthermore, these variations were in good agreement spectral slope variations of carbonaceous chondrites, particularly in the near-UV region. These results support the work of de Leon et al. (2012) and Alf-Lagoa et al. (2013) in identifying spectral slope variations and contributing to a three-part survey of B-type asteroids across different wavelengths. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2015.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 29-31).

Controlling factors on Mesozoic and Cenozoic metamorphism and deformation in the Maria Fold and Thrust Belt and Colorado River Extensional Corridor, Southeastern California and Western Arizona

Thu, 01 Jan 2015 00:00:00 GMT

Controlling factors on Mesozoic and Cenozoic metamorphism and deformation in the Maria Fold and Thrust Belt and Colorado River Extensional Corridor, Southeastern California and Western Arizona Pershken, James R The Maria Fold and Thrust Belt (MFTB) and Colorado River Extensional Corridor (CREC) were the sites of atypically extreme compression in Mesozoic time and extension in Cenozoic time, respectively. The orientations of these deformational structures are at odds with the Sevier and Laramide thrust belts and the Basin and Range Extensional Province surrounding these areas, a fact that remains largely unexplained. Data pertaining to metamorphic grade, deformational structures, and plutonism are compiled and reported in order to characterize compression and metamorphism. Field data on the 18.6 Ma Peach Spring Tuff are collected and presented and data on cooling ages are compiled in order to characterize extension. It is suggested that high metamorphic temperatures and ductile compressional structures are related to Late Cretaceous S-type plutonism; furthermore, it is suggested that later extension is related to earlier metamorphism and compression. It is demonstrated that the spread in attitudes of the Peach Spring Tuff correlates well with the degree of post- 18.6 Ma extension. Finally, a favored model is presented for the Mesozoic-Cenozoic evolution of the MFTB and CREC. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2015.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 40-46).

Establishing an unambiguous connection between grain size and style of sediment transport in the Lower Niobrara River, Nebraska, USA

Sun, 01 Jan 2006 00:00:00 GMT

Establishing an unambiguous connection between grain size and style of sediment transport in the Lower Niobrara River, Nebraska, USA Leung, Vivian The transport of sediment is often separated into two components, bedload and suspended load. This division is important because bedload has a dominant control on channel morphology while suspended load dominates the formation of overbank deposits. Experimental data has related the style of sediment transport to mean flow conditions and bed topography. However direct application of this method in natural, sandy rivers is difficult due to large variabilities in flow. We propose a method for determining local flow conditions using the distribution of grain sizes traveling in the water column. Local shear velocity is found by fitting the Rouse equation for suspended sediment transport to measured sediment concentrations. Empirical criteria for distinguishing between suspended load and bedload are used to determine the fraction of sediment traveling in each respective mode. Application of this method to the Niobrara River, Nebraska, shows that -80 % of the sediment is traveling as suspended load, ~ 20 % is traveling in a transitional mode between bedload and suspended load and less than 1 % is traveling as pure bedload. We establish an unambiguous connection between grain size and the style of sediment transport and highlight the importance of the transitional transport mode in natural systems. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 22).

Ozone chemistry during global glaciations : a possible climate feedback

Sun, 01 Jan 2006 00:00:00 GMT

Ozone chemistry during global glaciations : a possible climate feedback Hsiang, Solomon M A theory for changes in ozone chemistry during late Proterozoic global glaciations is developed. The possible significance of temperature, humidity, nitrogen oxides, reactive chlorine, lightning frequency, surface deposition and albedo as altered constraints on ozone processes is discussed. An elementary box model is developed by the author to make first order judgments regarding the significance of chemistry changes on ozone concentrations and its climactic effect. A one dimensional photochemical-transport model (Kasting, 1995) was used to more precisely determine the effects of global glaciations on ozone concentrations up to 5 hPa in several latitude bands. Reduced NO₂ availability in the stratosphere seems to dominate ozone's response (positive anomalies) in the stratosphere. Low temperatures, low humidity, reduced lighting frequency and altered chlorine and nitrogen chemistry collectively reduce ozone presence in the troposphere, however the overall sign of the tropospheric ozone anomaly depends heavily on poorly characterized deposition rates. With output from the one-dimensional photochemistry model, a time-varying ozone concentration field was assembled for the entire planet and used in snowball runs of the General Circulation Model (NCAR Community Atmosphere Model 3.0). These runs were compared to a controlled snowball run with a modern ozone field to discern the climactic significance of altered ozone. Results suggest that ozone concentrations during global glaciations might directly produce global average surface radiation anomalies of -1.5 ~ 1.5 W/m² , resulting in global average surface temperature anomalies of -0.5 ~ 0.5°K. Magnitude and sign uncertainties result from poorly known deposition rates for ozone over frozen surfaces and the simplicity of the modeling technique. The indirect effect of increasing stratospheric ozone, i.e. a reduction in atmospheric oxidative capacity, may result in positive anomalies of other green house gasses and is discussed as an area for further research. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.; Cataloged from PDF version of thesis. Pages 77-78 missing from original thesis.; Includes bibliographical references (pages 76-84).

Methods for the study of virus adsorption to metal oxide in order to improve ceramic water filters

Sun, 01 Jan 2006 00:00:00 GMT

Methods for the study of virus adsorption to metal oxide in order to improve ceramic water filters Dumas, Marion (Marion M.) As of 2002, 1.1 billion people lacked access to clean water, causing several million deahts each year from highly-infectious enteric diseases. It has been recognized that an appropriate way of addressing this problem may be to enhance the effectiveness and the usage of house-hold water treatment and storage (HWTS) systems. Ceramic filters are examples of HWTS systems. Ceramic filters decrease the concentration of bacteria by pore size filtration but are not able to filter the nanometer-size viruses. It is proposed that adding an adequate amount of metal oxides to the clay before firing the filters would allow the ceramic to adsorb the viruses present in the water. This thesis takes two steps towards evaluating this proposition. It demonstrates the microbiological methods needed to assess the presence of viruses in water and to carry out experiments with bacteriophages, used as model viruses. It also presents the theory necessary to understand, measure and model virus adsorption to surfaces. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.; Cataloged from PDF version of thesis. Some pages in the original thesis contain text that is illegible.; Includes bibliographical references (pages 91-93).

Stream profiles as a proxy for uplift in the San Bernardino Mountains

Sun, 01 Jan 2006 00:00:00 GMT

Stream profiles as a proxy for uplift in the San Bernardino Mountains Cornell, Katrina Muir Stream profile analysis provides new insight into the tectonic history of the San Bernardino Mountains of Southern California. The San Bernardino Mountains, along with the nearby San Gabriel Mountains, have been tectonically uplifted since the late Miocene due to transpression-related thrust faulting. Although regional uplift patterns are not as clear from this data as those of a stream profile analysis in the San Gabriel Mountains, the results observed indicate that this technique can extract useful tectonic data and provide a fast, inexpensive, and easy way to focus fieldwork in a region. For example, in the San Bernardino Mountains, stream profile interpretation from digital elevation models (DEMs) indicates the current/most recent uplift rates on the Yucaipa Ridge at the southern range front are only ~0.5-0.6 mm/yr, much lower than indicated by a published (U-Th)/He age-elevation transect. Also, a change in steepness index (ksn) values between the north and south sides of the Santa Ana Thrust Fault suggests differential uplift across it as recently as the mid to late Quaternary. However, there are important limitations to the method that render interpretations non-unique. For example, the channel downstream of the dam at Big Bear Lake is much steeper than adjacent streams; a tectonic explanation is unlikely. One possibility is that large landslide- and debris-flow-derived boulders have armored the channel and caused the river to oversteepen. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 30-32).

A digital path to environmental education

Sun, 01 Jan 2006 00:00:00 GMT

A digital path to environmental education Bassein, Emma (Emma R.) Digital technology has become completely engrained in the process of scientific research. Grade schools are beginning to incorporate computers and other digital devices into the learning process as tools for learning other subjects, including science. Educators have experimented with a variety of programs that incorporate computers, such as digital tutors, simulations of natural systems, and interactive simulations. This study aimed to demonstrate that handheld computers are a useful resource in problem-based learning environments. A "mini-curriculum", focused on making handheld computer-aided measurements of the key environmental parameters in marine estuaries, was designed and taught to eleven students from the Palmetto Ridge High School in Naples, Florida over a two week period. Students' reactions to both the curriculum and the computers were overwhelmingly positive. This proof-of-concept trial indicates that handheld computers have the potential to be a very useful tool in problem-based learning. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.; Cataloged from PDF version of thesis. Pages 25 and 37-39 missing from original thesis.; Includes bibliographical references (page 28).

Sensitivity study and stability analysis of the Marotzke and Stone ocean-atmosphere model under buoyancy and energy constraints

Sat, 01 Jan 2005 00:00:00 GMT

Sensitivity study and stability analysis of the Marotzke and Stone ocean-atmosphere model under buoyancy and energy constraints Wood, Christie L. (Christie Lynn) The oceanic circulation plays a significant role in earth's climate by transporting heat polewards. Here the ocean's thermohaline circulation is studied using the Marotzke and Stone four box ocean-atmosphere model under both the buoyancy constraint proposed by Stommel and the energy constraint proposed by Huang. Both a sensitivity study and stability analysis is performed. In the sensitivity study it is evident that the model under the buoyancy constraint reacted to variations in flow between ocean boxes, net incoming radiation gradient and longwave radiation reflection coefficient in the same manner regardless of whether it was in thermal mode or haline mode. Under the energy constraint the study yielded similar results in both modes, with the exception of the equilibrium temperature and salinity having opposite relationships to the energy parameter in the thermal and haline modes. The model under the buoyancy constraint under both limits becomes more sensitive to changes in both the net incoming radiation gradient and the longwave radiation reflection coefficient as the rate of flow between the two ocean boxes decreases. The model under the energy constraint, in contrast, becomes more sensitive to changes in the longwave radiation reflection coefficient as the energy parameter decreases but the model's sensitivity to changes in the net incoming radiation gradient is unaltered by changes in the energy parameter. This suggests that the model under the energy constraint is less sensitive to global climate changes. The stability analysis shows that the model under both the buoyancy and energy constraint is stable to realistic perturbations in temperature and salinity. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2005.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 44).

Permeability modifying processes : thermal cracking and crack healing of geomaterials

Sat, 01 Jan 2005 00:00:00 GMT

Permeability modifying processes : thermal cracking and crack healing of geomaterials Dorfman, Susannah M We explored two complementary mechanisms for change in porosity and permeability of geomaterials: thermal cracking and crack healing by diagenesis. A suite of thermal cracking experiments was performed on andesite plugs from the geothermal field in Awibengkok, Indonesia. Permeability (k) and specific storage capacity were measured by the oscillating flow method in a wide range permeameter, at room temperature, with effective pressures between 15 MPa and 95 MPa, before and after thermal cracking. The samples were cracked at 150 and 300 °C and ambient pressure. Andesite samples have low permeability, on the order of 10-²⁰ M² . With increased pressure, permeability is reduced by a factor of two. Contrary to expectations, thermal cracking reduced the permeability of this material by an order of magnitude. We also examined a set of samples from crack healing experiments performed on Sioux quartzite by M. Messar. In these experiments the quartzite permeability fell by three orders of magnitude within a few days when the samples were saturated with water and heated to temperatures from 300 to 500 °C and pressures from 25 to 200 MPa. In order to correlate Messar's permeability measurements and experimental conditions with visual observations of the pore structure (mainly consisting of grain boundary cracks), we took scanning electron microscope micrographs of the samples. We then counted the intersections of test lines with healed and unhealed cracks. This yielded a set of measurements of the crack area per volume of the quartzite. We found that the final permeability of the samples was related to the area per volume of unhealed cracks by a power relation. Combining the findings from the two sets of experiments, it seems that cracking and healing effects due to the ambient temperature and pressure in geothermal fields such as Awibengkok could eliminate any permeability through grain boundary scale cracks within a matter of days. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2005.; Cataloged from PDF version of thesis. Pages 29-37, 42 and 46 not in original thesis.; Includes bibliographical references (pages 44-48).

Determining land use change and desertification in China using remote sensing data

Thu, 01 Jan 2004 00:00:00 GMT

Determining land use change and desertification in China using remote sensing data Hutchison, Leah (Leah Ellen Ann) Desertification, the spread of desert-like conditions in arid or semiarid areas due to human influence or to climatic change, affects most arable land in arid and semi-arid China. This project provides an analysis of desertification in northeastern arid and semi-arid China to determine its spatial distribution, severity, and causes. It locates areas of desertification and identifies and ranks in order of importance their anthropogenic and climatological causes. It especially focuses on the savanna transition zone west of Beijing to see if climate factors or increasing population density can be correlated to land cover change. GIS (Geographic Information Systems) software is used to recognize locations of rapid land cover change. Statistical tests, such as unbalanced multi-way ANOVA, determine if climatic or anthropogenic factors can predict if an area is undergoing rapid land cover change. The climate and population data is resampled to an uniform 0.5' scale and converted into qualitative, data before statistical testing. This project tests if land cover change, a more difficult indicator to measure, can be predicted by analyzing trends in vegetation, precipitation, temperature, wind and population. Desertification is more likely and more severe in climates with low precipitation. Areas with low population density tend to have less severe land degradation than areas with medium or high density; this may be due to more intense land use in high population areas. Thesis: S.B. in Geosciences, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2004.; Cataloged from PDF version of thesis. Some pages in original thesis contain text that run off the edge of the page.; Includes bibliographical references (pages 61-64).

Two-dimensional, viscous flow modeling of roll-back subduction : numerical investigation into the role of slab density in subduction dynamics

Thu, 01 Jan 2004 00:00:00 GMT

Two-dimensional, viscous flow modeling of roll-back subduction : numerical investigation into the role of slab density in subduction dynamics Haurin, Jessica L. (Jessica Lyn) Observations of retreating subduction systems in the Mediterranean region suggest the density of subducting lithosphere is dynamically related to trench retreat rate and upper-plate deformation. Most numerical and analog studies of retreating subduction systems have not explored the effects of lithospheric density variations on subduction processes. This study is a preliminary effort to construct a two-dimensional, viscous flow model of "roll-back" subduction to explicitly examine how slab density influences retreat rate, mantle flow, and slab geometry. For a given lithosphere-mantle density contrast, the model computes the evolution of a viscous, thermal slab using a finite element code for incompressible convection (ConMan). Imposed velocity boundary conditions guide lithospheric material into a uniformly weak "subduction zone" and out into the mantle below, generating stable, asymmetric subduction. Slabs driven faster than the "intrinsic" (dynamically consistent), steady-state retreat rate of the system (vr) are characteristically arcuate, pushed upward from the base of the mantle layer by strong horizontal "return flow" beneath the descending lithosphere. Slabs driven slower than vr are sigmoidal: the slabs steepen at depth, where vertical buoyancy forces overcome lateral viscous forces set up by weak surface velocities. The diagnostic behaviors of slabs driven faster and slower than vr define a set of qualitative criteria (slab geometry, mantle flow patterns) for converging on the consistent, steady-state retreat rate of the system. For slab-mantle density contrast [delta]p = 198 kg/m³ (defined as the density difference between lithosphere at surface of the system and mantle material at the base of the system), vr ~~ 16 mm/yr. The slab is roughly planar, with 500 dip. For [delta]p = 168 kg/m³, vr is slightly slower (14 mm/yr), and steady-state slab geometry is nearly identical (moderately-dipping planar surface). It is found that the angle at which lithospheric material is forced into the mantle does not significantly affect either steady-state retreat rate or slab geometry. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2004.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 37-38).

H107[alpha] recombination-line emission, 4800-MHz and 1666-MHz continuum emission in the HII region RCW38

Wed, 01 Jan 2003 00:00:00 GMT

H107[alpha] recombination-line emission, 4800-MHz and 1666-MHz continuum emission in the HII region RCW38 Vigil, Miquela, 1981- We present results from observations of H107[alpha] recombination-line emission and the related 4800 MHz continuum emission of the HII region RCW 38 using the Australia Telescope Compact Array. We find the continuum emission to be concentrated in a ring-like structure with the 05 star, IRS2, approximately centered in the cavity within the ring. The temperature of the ionized gas ranges from 5200 to 7500 K and the emission is optically thin. The H107[alpha] line emission appears to be confined within the continuum ring. We also find the continuum ring to encircle the peak in the diffuse X-ray gas. The radio continuum emission matches closely to NIR observations with a bright western ridge containing the peak in the 10[mu]m emission known as IRS1 (Frogel et al. 1974) apparent in both observations. From calculations of continuum and line parameters, we estimate the spectral type of the ionizing source for the region to be an 05/06 star which is consistent with the spectral type of IRS2. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2003.; Cataloged from PDF version of thesis. In title on title page, "[alpha] appears as lower case Greek letter. "May 21, 2003."; Includes bibliographical references (page 31).

Stellar occultation investigations of Pluto's atmosphere

Wed, 01 Jan 2003 00:00:00 GMT

Stellar occultation investigations of Pluto's atmosphere Salyk, Colette Vanessa We investigate the shape of Pluto's atmosphere using data from the occultation of the V=15.7 star P131.1 by Pluto on 2002 Aug 21 (UT). We find that Pluto's atmosphere, as projected onto the sky, is noticeably non-circular. This implies an overall ellipsoidal shape, which could be an indication of high winds and/or latitudinal stratification. We decide to compare our results to those obtained from datasets of the occultation of P8 by Pluto on 1988 June 9 (UT). Previous analyses of these datasets by Millis et al. (1993) had led to the conclusion that Pluto's atmospheric shape did not deviate from that of a sphere. However, we find that the 1988 datasets do not conclusively demonstrate that this is the case. We conclude that Pluto's atmosphere is currently non-spherical and could have been non-spherical at the time of the 1988 occultation. Implications for high winds and/or latitudinal stratification present exciting possibilities to be investigated by the upcoming New Horizons mission to Pluto. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2003.; Cataloged from PDF version of thesis. Page 21 missing from original thesis.; Includes bibliographical references (pages 27-28).

Analysis of lunar oxygen production methods under varying lunar conditions

Wed, 01 Jan 2003 00:00:00 GMT

Analysis of lunar oxygen production methods under varying lunar conditions Neubert, Joshua, 1981- This research thesis compares the major, most feasible methods of providing the needed amounts of oxygen on the lunar surface for a future human mission. Past studies are combined to provide a comprehensive look at each process and their processing requirements (for example, the mass a processing plant requires, the speed at which the oxygen could be produced, and the cost of setting up such a processing system). There are three methods of in-situ oxygen production that will be researched: hydrothermal reduction, carbothermal reduction, and water/ice electrolysis. Transportation from the Earth is also noted as a basis of comparison. These three methods were chosen because they are the three simplest, most studied methods of regolith reduction to produce oxygen. There have been several studies done on these methods from which I base my research. Pure electrolysis is being studied because of the possibility of water ice at the lunar poles. All three processes are compared and analyzed under various lunar constraints. These constraints limit the feedstock of the system at different locations on the lunar surface. It is found that the water ice concentrations estimated at the north-pole are significantly above that needed to make ice electrolysis the most beneficial method of extraction. However, in mid-latitudes and the south-pole such a definite conclusion is not yet seen. In the south polar regions if the water ice concentration is in the lower half of the bound estimated then ice electrolysis is not the most beneficial, yet if it is in the upper half it will be at least more beneficial than the hydrothermal process, if not the most beneficial. More research must be conducted on the carbothermal system to make definite analysis quantitatively conclusive. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2003.; Cataloged from PDF version of thesis. Page 36 missing from original thesis.; Includes bibliographical references (page 37).

A statistical approach to predicting snowfall using the SPF

Wed, 01 Jan 2003 00:00:00 GMT

A statistical approach to predicting snowfall using the SPF Acosta, Wesley C. (Wesley Cordell) A snowfall potential probability density function is introduced that uses an alternate method of statistical analysis in predicting snowfall by using concepts of normal probability distributions. The snowfall potential function (hereby referred to as the SPF) assumes certain identifiers are associated with snowfall of varying intensities. The conceptual relation of each identifier with snowfall is explained and the statistical association of each identifier to the SPF is determined by a correlation coefficient and the relative strength of that particular identifier with respect to the expected value (the mean). The intensity of the snowfall over an area is estimated by calculating the SPF's overall deviation from some expected value, where any given SPF value can estimate a snowfall value. The framework for the SPF is explained using a simple model. The correlation coefficients for several identifiers are calculated and an example of an application of the SPF is demonstrated. Further hypotheses are given as to how the SPF could ultimately be used to provide possible higher-accuracy snowfall forecasts through the development of time-dependent functions for each identifier and the assigning of specific functional forms for the SPF based on region of analysis, storm type (i.e.: coastal, Alberta clipper), and storm track. 2 Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2003.; Cataloged from PDF version of thesis. Pages 15, 16 and 35 not in original thesis.; Includes bibliographical references (pages 38-40).

Mercury emissions inventories in the Lake Superior states

Fri, 01 Jan 2016 00:00:00 GMT

Mercury emissions inventories in the Lake Superior states Berg, Elizabeth (Elizabeth J.) Mercury pollution can cause harmful impacts on human health and the environment, a concern that is magnified in marine environments like the Great Lakes. While there are many local, national, and global efforts to track emissions, one key complication to accurately estimating atmospheric mercury is the disagreement between the two national EPA inventories, the National Emissions Inventory (NEI) and Toxics Release Inventory (TRI), which differ in both location and magnitude of emissions. By comparing the NEI and TRI datasets from 2008 and 2011 in the states bordering Lake Superior, this study aims to uncover potential biases in each inventory and determine when a given inventory is more accurate. Additionally, year-to-year TRI emission totals since 2000 are studied to produce a more precise visualization of mercury trends in the Lake Superior Basin. The most notable difference between the two inventories was the absence of mining in TRI, one of the most significant sectors in NEI for both years studied. The utilities sector, however, showed more agreement between the two inventories. The relationship between the NEI and TRI numbers for the facilities within the utilities sector that were found in both datasets was found to be TRI = (1.206)NEI, matching the results from a previous study. Additionally, the study of the yearly TRI data from 2000 to 2014 showed that while average emissions per facility have been declining since 2000, particularly in the manufacturing sector, there is a surprising degree of variability in yearly totals than expected, exposing a potential topic of future research. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 41-43).

Analysis of magnetic activity cycles in solar analogs using Solar - Stellar Spectrograph data

Fri, 01 Jan 2016 00:00:00 GMT

Analysis of magnetic activity cycles in solar analogs using Solar - Stellar Spectrograph data Doan, Duy Anh N The Solar-Stellar Spectrograph (SSS) Project includes frequent observations of 30 - 50 Sun-like stars to address a wide variety of questions regarding the nature of stellar magnetic activity cycles. The magnetic activity cycles of 18 stars in the SSS project are analyzed using the Lomb Scargle method of least-squares spectral analysis. Periodograms reveal that out of 18 stars, 9 stars have one magnetic cycle and 6 stars have two magnetic cycles, with periods ranging from 2 years to 17 years. The remaining stars show significant variability but without pronounced periodicity. Most of the detected cycles have a false alarm probability (FAP) well below 10-3 The results for a number of stars are compared and confirmed with earlier observations by Mount Wilson Observatory's project, published by Baliunas et. al. (1995). Four more stars are added to the plot of activity cycle period - rotational period relation by Bohm-Vitense (2006), and they all lie on either the active sequence or the inactive sequence. This result, together with the fact that several stars have two different cycles lying on different sequences, lends more evidence to the hypothesis that stars have multiple dynamos but are dominated by one of them. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 30-31).

Constraints on passive margin escarpment evolution from river basin reorganization in Brazil

Fri, 01 Jan 2016 00:00:00 GMT

Constraints on passive margin escarpment evolution from river basin reorganization in Brazil Douglas, Madison M Escarpments are present on passive margins around the world, but their evolution is poorly understood. Some geologists interpret escarpments as stationary features, whereas others have argued that they are retreating inland faster than a kilometer per Myr. I investigate Brazilian escarpments by determining whether or not the river networks on either side of the escarpment are in erosional equilibrium with each other. My approach is based on the premise that rivers on opposite sides of a stationary escarpment would be eroding at the same rate (erosional equilibrium), whereas rivers on opposite sides of a mobile escarpment would be eroding at different rates (erosional disequilibrium). I use a recently developed technique called chi mapping to assess the erosional disequilibrium of river networks along the Brazilian escarpments. For comparison, I also compile erosion rates on either side of the escarpments from cosmogenic "Be measurements in the existing literature, and use these to calculate recent retreat rates of the escarpments, which fall between 4 and 40 m/Myr. I determine that chi mapping and cosmogenic erosion rates agree on the direction of escarpment movement, but disagree on the magnitudes of the retreat rates. I also estimate the percentage of drainage area exchanged by stream capture as the escarpment drainage divide moves across the landscape. Using two different estimation methods, I find that less than 40% of drainage area is exchanged by stream capture, making divide migration the dominant mechanism for drainage basin reorganization. If my estimates of recent escarpment retreat rates are representative of long-term rates, the Brazilian escarpments have retreated up to 5 km since their formation during the Cretaceous rifting event. My analysis shows that the topographic retreat of the Brazilian escarpments could have been driven by drainage basin disequilibrium resulting in divide migration. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 37-40).

Recent changes in the variability and seasonality of temperature and precipitation in the Northern Hemisphere

Fri, 01 Jan 2016 00:00:00 GMT

Recent changes in the variability and seasonality of temperature and precipitation in the Northern Hemisphere Hui, Katrina L This study investigates recent changes in the variability and seasonality of temperature and precipitation in the Northern Hemisphere. The mean and variance of daily temperature and precipitation anomalies are calculated for each year over a 35-year period and compared to a base period. For temperature in the Northern Hemisphere, a noticeable warming trend amplified in the higher latitudes was observed, as well as a significant decrease in variability in the mid and high latitudes. For precipitation in the Northern Hemisphere, a drying trend and decreasing trend in variability were observed in the mid latitudes during summer. The seasonal cycles of both temperature and precipitation were also analyzed. The trends in temperature seasonal amplitude and phase were studied and revealed some influence of Arctic sea ice loss that changes the seasonality of local temperature, and Arctic amplification that potentially influences temperature seasonality in the mid and high latitude land regions. To determine whether the changes in temperature seasonality may affect temperature variance, analyses were performed by removing the phase trends from the temperature data using two methods. The phase trend-removed temperatures were found to have no prominent trends in variance. This suggests that changes in the temperature variance may be related to changes in temperature seasonality. To study what affects precipitation variability, the coefficient of variation (ratio of standard deviation to mean), which determines the shape of the mixed gamma probability distribution function (PDF) of precipitation, was studied. It was found that the mean and variance of precipitation have a fixed ratio over time, suggesting that the shape of the precipitation PDF has not changed. Therefore changes in the precipitation variance in the midlatitudes could be simply explained by the change in the mean precipitation in the same region. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 59-60).

Records of Great Basin precipitation during MIS 11 from two Lehman Cave stalagmites

Fri, 01 Jan 2016 00:00:00 GMT

Records of Great Basin precipitation during MIS 11 from two Lehman Cave stalagmites Neary, Ashling Trace elements (Mg/Ca and Sr/Ca) and stable isotopes ([delta]13C and [delta]18O) were measured in two coeval stalagmites, LC3 and BT1, from the Lehman Caves, Nevada. BT1 spans 388 to 384 ka. The LC3 record is split into two parts due to a hiatus observed through fluorescent imaging. The section prior to the hiatus spans 411 ka to 402 ka. The post-hiatus section of the stalagmite has a single age of 383 ka; an age model cannot be constructed for this part of the record. These stalagmites span Marine Isotope Stage 11 (MIS 11), a long interglacial that occurred around 424-374 ka. Comparison with more recent stalagmite records has shown prior calcite precipitation to be the dominant control on Mg/Ca and [delta]13C in the cave. The trace element and stable isotope records obtained point to an arid climate in the Great Basin during MIS 11. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 26-29).

Analysis of Pluto's light curve to detect volatile transport

Fri, 01 Jan 2016 00:00:00 GMT

Analysis of Pluto's light curve to detect volatile transport Mansfield, Megan (Megan L.) Changes in the volatile distribution on Pluto's surface and in its atmosphere are expected to occur over its orbital path due to varying surface insolation[14]. To investigate these changes, a model was created to synthesize light curves of Pluto, given the viewing geometry and surface albedo distribution. Using an initial surface albedo distribution based on images taken by New Horizons, changes in the light curve mean magnitudes and amplitudes over time were compared to the smallest magnitude changes detectable by a variety of telescopes. The model predicts that yearly observations on a large ground-based telescope, such as the 6.5-meter Magellan telescopes, could observe magnitude changes due to both changes in viewing geometry and surface albedo changes. The model can be compared to future observations to estimate how much surface albedo change is necessary to produce the observed light curves, and can therefore be used to link observational data to physical changes on Pluto's surface and the methods of volatile transport responsible for those changes. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 65-66).

National technological and military prestige heavily influenced the development of early United States space policy

Tue, 01 Jan 2002 00:00:00 GMT

National technological and military prestige heavily influenced the development of early United States space policy Barboza, Michael A. (Michael Anthony) The purpose of this thesis is to discuss the relationship between U.S. space policy and: 1) national technological prestige 2) military superiority 3) and ultimately the political competition between the United States and the Soviet Union. The paper will focus primarily on national and military prestige, while briefly touching on the price tag of the early space advancements. It will concentrate on the early days of space exploration. The thesis will examine the impact the Russian satellite, Sputnik, had on the American people and the reaction of the United States. The thesis will also look at the beginning of the Apollo program and the decision to send man to the Moon. In conclusion, the thesis will look at a possible future for the United States space program and analyze the decision of America's leaders to abandon ambitious endeavors since the Apollo Moon landing. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2002.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 21).

Relating size and spectral reflectance properties of S-type asteroids

Mon, 01 Jan 2001 00:00:00 GMT

Relating size and spectral reflectance properties of S-type asteroids Malcom, Lindsey Ellen, S.B. Massachusetts Institute of Technology The spectral slopes of 701 S-type asteroids have been statistically shown to depend on asteroid size. The spectral reflectance data were taken during the second phase of the Small Main-belt Asteroid Spectroscopic Survey. It was concluded that larger S-type asteroids have a higher spectral slope than smaller S-type asteroids, implying that S-type asteroids are likely to be undergoing a time-dependent surface alteration process, known as space weathering. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2001.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 47-48).

An examination of trace element concentrations across calcite/aragonite transitions in a Madagascan stalagmite

Sun, 01 Jan 2017 00:00:00 GMT

An examination of trace element concentrations across calcite/aragonite transitions in a Madagascan stalagmite Brent, Kaylee Calcite and aragonite speleothems have been used for the past few decades to provide paleoclimate information, but in speleothems of mixed mineralogy the signal of mineral changes can complicate understanding of climate signals also present. This mineral signal must therefore be examined and controlled for. In this work, ICP-MS (inductively-coupled plasma mass spectrometry) analysis of trace element (strontium and magnesium) incorporation into calcium carbonate provides additional evidence for a shift in CaCO3 polymorphs identified via XRD (xray diffraction) analysis of speleothem AB-2 from Anjohibe Cave, Madgascar. The ICP-MS Sr/Ca data qualitatively supports the Sr/Ca data collected by the XRF core scanner, exhibiting a sharp decrease in value across the identified mineral transition. A corresponding increase in Mg/Ca revealed by the ICP-MS provides further evidence for a change from aragonite to calcite at this location. This mineralogical change occurred between 870-880 CE (+/- 13 years) is nearly concurrent with a shift in [delta]13C isotopes that was identified in previous work on this speleothem and attributed to an ecological shift in dominant photosynthetic pathways (Bums et al 2016). A second, control section was identified as pure calcite by XRD analysis, but revealed Mg/Ca and Sr/Ca ratios characteristic of mineralogical transitions, suggesting that there may have been layers of aragonite that have recrystallized to calcite since deposition. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 21-23).

Optical analysis of the Wallace Astrophysical Observatory 24-inch and Magellan I 6.5-meter telescopes

Sat, 01 Jan 2000 00:00:00 GMT

Optical analysis of the Wallace Astrophysical Observatory 24-inch and Magellan I 6.5-meter telescopes Wu, Janet P., 1978- The goal of this thesis is to propose a layout for the Wallace Astrophysical Observatory (WAO) 24-inch optical system that would utilize the full potential of the telescope and a new CCD imaging instrument. An optical analysis of the 6.5-meter Magellan I telescope was first performed to determine the optimal mounting location for the Raymond and Beverly Sackler Magellan Instant Camera (MAGIC). The analysis method used for the Magellan I model was then applied to the WAO 24-inch telescope. The results of the optical analysis of the WAO 24-inch model suggest that the optimal layout would follow a Cassegrain model with a focal ratio of between 15.3 and 16.6 to obtain image sizes of approximately 1.0 arcsecond or less over a field of up to 26.4 arcminutes in diameter. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2000.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 61).

Does the theory of parameterized conveciton apply to layered mantle convection?

Sat, 01 Jan 2000 00:00:00 GMT

Does the theory of parameterized conveciton apply to layered mantle convection? Hsung, Jenwa There are numerous models for convection of the Earth's mantle, the end cases of which are whole-mantle convection and layered convection. Heat flow is an important consideration in the evalution of these models. Simple thermal evolution models based on boundary layer theory have in the past been used to look at these models. However, insufficient attention has been paid to how well the theory applies. This was particularly uncertain for the case of layered convection with a radiogenically enriched lower mantle. I modified the finite-element code ConMan to include exponentially decaying internal heating so that the radiogenic isotopes in the lower layer would be accurately represented, and compared the experimental results of a one-layer case and a two-layer case to the theoretical solutions for those cases from boundary layer theory. It turns out that boundary layer theory does indeed seem to be accurate for the case of a two-layered convecting system with a radiogenic lower layer that produces exponentially decaying internal heating. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2000.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 70-71).

Geochronological constraints on the Trinity diamictite in Newfoundland : Implications for Ediacaran glaciation

Fri, 01 Jan 2016 00:00:00 GMT

Geochronological constraints on the Trinity diamictite in Newfoundland : Implications for Ediacaran glaciation Pu, Judy (Judy P.) The Avalon terrane in Newfoundland includes the Ediacaran Gaskiers Formation, which has been associated with a Snowball glaciation event. The complicated regional stratigraphy and lack of precise geochronological constraints has made it difficult to determine the spatial and temporal extent of the Gaskiers glaciation. Recent recognition of a diamictite facies on the nearby Bonavista Peninsula correlative with the Gaskiers diamictite has allowed for new, high-precision geochronological constraints on the Gaskiers glaciation and constrains the duration of the event to less than 390 ±320 kyr. The Snowball Earth hypothesis requires that glaciation continued for several millions of years so that CO2 could build up to high enough levels in the atmosphere for catastrophic deglaciation; the short duration of the Gaskiers event makes it unlikely to have been a Snowball event. Further geochronological studies are needed to determine whether the Gaskiers glaciation was a discrete event or if it was a glacial maximum in a longer Ediacaran ice age. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 21-26).

Finding the location of Planet Nine

Sun, 01 Jan 2017 00:00:00 GMT

Finding the location of Planet Nine Downey, Brynna G To find Planet Nine, we use N-body simulations to find the true anomaly of Planet Nine that would render distant KBOs the most stable. We obtain an interval of 162-198°matching the intervals given by Medvedev & Vavilov (2016) of 176-184° and Brown & Batygin (2016) of 180°. According to our results, Planet Nine should reside in the constellation Lepus. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, June 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 19).

Air quality applications of extreme value theory : return levels of extreme ozone events in Chicago and surrounding areas

Sun, 01 Jan 2017 00:00:00 GMT

Air quality applications of extreme value theory : return levels of extreme ozone events in Chicago and surrounding areas Rider, Elizabeth Ndayu To quantify the effects of the NO, SIP call in urban and rural locales, surface ozone data from the Air Quality System is analyzed. Methods from extreme value theory are applied to calculate and compare 20-year return levels at 5 urban and 17 rural/suburban sites in Illinois based upon maximum daily 8-. hour average ozone concentrations from summer (JJA) for two periods (1992- 2002 and 2003-2013) and a threshold of 70 (ppb). Between the two periods, 21 out of 22 sites experienced a decrease in 20-year return levels. The magnitude of these decreases does not indicate a strong correlation between population density and air quality improvements, however, further analysis is required. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 21-24).

Distribution of NMHC ratios in the Pacific during PEM-West B and PEM-Tropics A

Sat, 01 Jan 2000 00:00:00 GMT

Distribution of NMHC ratios in the Pacific during PEM-West B and PEM-Tropics A Casso, Christopher Chay Under the auspices of NASA's Global Tropospheric Experiment (GTE), the Pacific Exploratory Missions (PEM) have collected numerous air samples of many regions of the troposphere. Data from PEM-West B (February 7 to March 15, 1994), and PEM-Tropics A (August 15 to October 5, 1996) have been used here to study non-methane hydrocarbon (NMHC) ratios and to compare pollution transport by large scale convection and subsidence, as well as horizontal transport across the Pacific. For PEM-Tropics A, 7 cases are studied, each involving different aspects of transport. Persistent circulation features in the South Pacific played a significant role in NIMHC ratio distribution and processing. For PEM-West B, sources of a large pollution region are studied and compared to equatorial transport. NMHC ratios were found to be useful tracers of pollution distribution through the troposphere. The contrasts of these ratios across relatively small distances, particularly on either side of the South Pacific Convergence Zone in PEM-Tropics A, suggest that convection shapes pollution transport and distribution, particularly in the South Pacific. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2000.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 21-22).

Cost benefit analysis of process change implementation : alternate wet cleaning technology in the semiconductor manufacturing industry

Mon, 01 Jan 2001 00:00:00 GMT

Cost benefit analysis of process change implementation : alternate wet cleaning technology in the semiconductor manufacturing industry Vazirani, Raj A. (Raj Anand) Maintaining wafer surfaces free of contamination is an essential requirement for the successful fabrication of semiconductor devices. With the growing trend of increased device complexity and reduction of device feature sizes, the area of wet cleaning of substrate surfaces has gained importance. The existence of organic and metallic contaminant particles and thin films on a wafer surface can drastically reduce line yield. Recent improvements in wet cleaning technology have presented alternate wafer cleaning techniques. The J.T. Baker clean process is a two step replacement for the four step RCA clean which is the current industry standard. The J.T. Baker clean process involves a significant reduction in chemical costs, process time, volume of disposed effluent, and parts usage. Furthermore, the J.T. Baker clean process eliminates the use of environmentally hazardous chemicals such as hydrochloric acid and ammonium hydroxide. However, process change in high volume semiconductor manufacturing facilities presents high levels of risk. A cost benefit model can be used to clearly outline the potential cost benefits and risks associated with implementing a process change in the semiconductor manufacturing facility. Only after understanding the risks involved and having a clear sense of the potential for financial gain can an informed decision on process change be made. This study used the Intel Fab 12 fabrication facility in Chandler, Arizona as a case study to model cost benefits and risk factors associated with implementing the J.T. Baker clean process. It was found that an expected value of cost savings of $285,000 per year could be achieved by replacing the RCA clean method with the J.T. Baker clean process. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2001.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 29).

Technical choice in pottery production : a west Mexican example

Mon, 01 Jan 2001 00:00:00 GMT

Technical choice in pottery production : a west Mexican example Meanwell, Jennifer L. (Jennifer Lauren) This thesis identifies the pottery engineering techniques of ancient Mexican potters from the site of La Queseria in the Balsas depression of Guerrero. I used data from petrography, geologic maps, clays from the area, x-ray diffraction and mechanical testing to determine whether these potters were using different clays for different functional designs. I determined that the potters used local clay for all pots, that some relation exists between the function of the pot and its material and processing technology, and that hence these potters were engineering their pottery. Thesis: S.B. in Archaeology and Materials, Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2001.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 69).

Oxygen precipitate studies in silicon for gettering in solar cell applications

Mon, 01 Jan 2001 00:00:00 GMT

Oxygen precipitate studies in silicon for gettering in solar cell applications Salomon, Ashley Oxygen precipitates in silicon can be used (in a process called internal gettering) as sites of heterogeneous nucleation of precipitates of iron and other transition metal that are harmful to solar cell device operation. Oxygen precipitate densities in p- (10¹⁴ boron atoms/cm³) wafers were quantified using chemical etch techniques. The precipitate densities were then used to estimate times to getter iron based on a diffusion limited precipitation model. Oxygen precipitate densities in p++ (10¹⁹ boron atoms/cm³) wafers were quantified using chemical etch techniques. High levels of boron in p++ wafers make quantifying precipitate densities particularly difficult, via etching, or other methods because precipitate densities in highly doped wafers are very high and the size of precipitates small. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2001.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 31).

Optical absorption of bismuth silicon oxide (Bi₁₂SiO₂₀) crystals

Mon, 01 Jan 2001 00:00:00 GMT

Optical absorption of bismuth silicon oxide (Bi₁₂SiO₂₀) crystals Lee, Grace W. (Grace Wang) The purpose of this work is to characterize the optical absorption in bismuth silicon oxide (Bi₁₂SiO₂₀) crystals grown using the Bridgman technique and to identify electronic transitions responsible for absorption. Optical measurements were taken in the range of 0.4 - 11 pm at 300 K and 77 K using a spectrometer. The results show that near the band edge, there is evidence of indirect transitions at 2.3 eV and excition transitions at 1.8 eV. Low temperature measurements revealed peaks of free carrier absorption in the visible light range at 1.7 eV and 2.1 eV. Illuminated samples at low temperature revealed empty donor levels in the visible range at 1.6-1.9 eV and 2.1 eV, indicating the presence of the photochromic effect and photorefractivity. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2001.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 23).

Diffuse double-layer interaction for nonspherical colloidal particles

Mon, 01 Jan 2001 00:00:00 GMT

Diffuse double-layer interaction for nonspherical colloidal particles Jhon, Mark The DLVO theory of colloids is used to consider the stability of clay colloid particles. An approach to colloid physics using classical electrostatic methods is presented. Specifically, the electrical double layer is examined using computational methods. To this end, the Poisson-Boltzman equation is solved numerically for geometries corresponding to interacting clay particles. The interaction energies of double layers is calculated for several particle configurations. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2001.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 35-36).

Fabrication of In₂(Se, Te)₃ chalcogenide thin films by thermal co-evaporation

Mon, 01 Jan 2001 00:00:00 GMT

Fabrication of In₂(Se, Te)₃ chalcogenide thin films by thermal co-evaporation Gupta, Shikha, S.B. Massachusetts Institute of Technology In₂(Se, Te)₃ III-VI chalcogenides belong to a unique class of phase change materials that have interesting optical and electrical properties, making them suitable for a wide variety of applications, including absorbers for solar cells and storage materials in memory devices. A greater understanding of how different growth parameters influence the crystallinity and microstructure of such chalcogenide thin films can lead to an enhanced ability to manipulate the materials for desired optoelectrical characteristics. The purpose of the following thesis was threefold. The first was to fabricate homogeneous, single-phase thin films of In2(Se, Te)₃ using thermal co-evaporation of elemental In and (Se, Te) in a high vacuum vapor deposition chamber. The In₂(Se, Te)₃ samples prepared by this method were found to be single phase textured films. Since re-evaporation of (Se, Te) from the films has previously resulted in deviations from the stoichiometric In₂(Se, Te)₃ compound [1], the second element of this thesis involved the microstructural characterization of films deposited with an excess of (Se, Te). The results from XRD and AFM reveal that after annealing the films the excess material does not manifest itself in any observable manner. Preliminary results from RBS and EDS reveal that some of the excess material may actually be evaporating through the 50 Å A1₂O₃ capping layer deposited on the film's surface, though further analysis with Auger and XPS will be necessary to enhance the understanding of what happens to the excess material. The third element was to assess how temperature and duration of post deposition thermal treatment influenced the crystal structure and surface morphology of the films. The films were annealed at temperatures ranging from 473 to 673K for 5 minutes, 1 hour, and 4 hours. Results from XRD showed that vacuum annealing of the samples at temperatures above 623K for times above 1 hour consistently produced well-oriented thin films of high crystalline quality. Higher annealing temperature resulted in films with higher crystallinity, whereas annealing durations longer than 1 hour did not contribute significantly to the film phase or crystallinity. AFM measurements of surface morphology before and after annealing showed that the roughness of the films before annealing was on the order of a few angstroms, whereas large, distinct grains and surface inhomogeneites were present on the sample surface after annealing. Again, no observable change was reported for films with excess (Se, Te) indicating that the single-phase compound that formed was very stable. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2001.; Cataloged from PDF version of thesis. "May 2001."; Includes bibliographical references (pages 46-47).

Materials characterization and transmission analysis in erbium-doped gallium nitride microresonator structures

Mon, 01 Jan 2001 00:00:00 GMT

Materials characterization and transmission analysis in erbium-doped gallium nitride microresonator structures Gibbons, David M GaN:Er is an attractive material for room temperature 1.54 pm luminescence enhancement devices for use in telecommunications because it does not experience thermal quenching at room temperature like Si:Er and can be electronically pumped. GaN:Er layers grown by molecular beam epitaxy (MBE) on single crystal substrates have shown excellent room temperature 1.54 [mu]m luminescence, but to integrate GaN:Er into microresonator devices it is necessary to grow a good quality GaN:Er film on an amorphous substrate. This thesis examines the optical properties and morphology of GaN:Er layers grown on Si₃N₄ and SiO₂ substrates, and evaluates two microresonator devices with incorporated GaN:Er layers. GaN:Er layers grown by MBE on SiO₂ and Si₃N₄ substrates were shown to give room temperature luminescence comparable to that of GaN:Er grown on (11 1)Si. GaN:Er layers grown on a buffered oxide etched Si₃N₄ substrate showed the best luminescence. The ability to grow good quality layers on amorphous substrates allows GaN:Er to be used in waveguide devices, the first of which studied was the microring resonator. Microring resonators were made by depositing a blanket GaN:Er layer on patterned Si₃N₄ microring structures. These structures were damaged, and transmission measurements were not possible. When looking at surface roughness measurements it appears that channel waveguide structures are unsuitable for GaN:Er grown on amorphous substrates, and so a ridge waveguide structure is proposed to lower this surface roughness scattering loss. A microcavity with a GaN:Er defect layer and a-Si/a-SiO₂ stacks was fabricated and tested for luminescence enhancement. The refractive index of GaN:Er was determined by reflectance measurements to be 2.1. The layer was not of uniform thickness which led to a broad resonance peak, but a distortion of the spectrum including a lower luminescence at the 1517 nm peak and a higher luminescence at the 1557 nm peak were observed, which suggests enhancement by the microcavity. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2001.; Cataloged from PDF version of thesis. "June 2001."; Includes bibliographical references (pages 47-48).

Finite element modeling of the human eye

Mon, 01 Jan 2001 00:00:00 GMT

Finite element modeling of the human eye Chan, Venetia (Venetia V.) A three-dimensional finite element model was created to analyze the mechanical interactions between the various substructures within the human eye. During certain activities, mechanical interactions may lead to a resultant distribution of stresses within the eye that may in turn produce various retinal diseases. The entire eye was modeled using dynamic finite element analysis to incorporate the mechanical effects of all of the substructures on the retina. A set of mechanical properties for each substructure was determined from previously published studies. Saccadic motion was modeled in the normal human eye to determine the location and magnitude of peak stresses in the retina and optic nerve head during initial loading. After 0.6125 ms, stresses as high as 5.4 x 10⁷ Pa were reached. The peak stresses occurred in the portions of the retina and the optic nerve head close to the boundary between these two substructures. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2001.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 37-38).

Evidence of thermal equilibration in large-scale atmospheric blocking episodes over Europe and the North Atlantic during winter

Sun, 01 Jan 2012 00:00:00 GMT

Evidence of thermal equilibration in large-scale atmospheric blocking episodes over Europe and the North Atlantic during winter Kowch, Roman S Atmospheric thermal equilibration occurs when all thermal forcings diminish. Characteristics of equilibration include low diabatic heating and calm conditions throughout the atmospheric column. Large-scale planetary waves can remain in these equilibrated states for long time periods, as identified in previous work. Relationships between thermal equilibration and large-scale atmospheric blocking episodes however have not been explored in much detail previously. In this paper we evaluate whether or not thermal equilibration becomes more evident in blocking episodes. We identify wintertime, large-scale blocking episodes over the North Atlantic and Europe using a dynamical blocking index on the ECMWF ERA40 reanalysis dataset. After identifying episodes, evidence of thermal equilibration is presented and analyzed through global composites of atmospheric variables in blocked and nonblocked situations. Relationships between potential vorticity and streamlines are also described and presented through scatter plots. Results from composites, and primarily scatter plots, provide significant evidence that thermal equilibration is more probable in blocking episodes than in non-blocked states. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2012.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 60-61).

Irradiated recycled plastic as a concrete additive for improved chemo-mechanical properties in hardened cement pastes

Sun, 01 Jan 2017 00:00:00 GMT

Irradiated recycled plastic as a concrete additive for improved chemo-mechanical properties in hardened cement pastes Schaefer, Carolyn (Carolyn E.) Portland cement based concrete production contributes heavily to greenhouse gas emissions. Thus a need exists for the development of durable and sustainable concrete with a lower carbon footprint. This can be achieved when Portland cement is partially replaced with another material without compromising the concrete's strength. The use of waste plastics in concrete has been explored as a means of improving concrete's mechanical properties while also providing an efficient way to both re-purpose waste plastic and partially displace cement for the purpose of reducing carbon emissions. This replacement, however, typically comes with a sacrifice of compressive strength. This work discusses the design for and progress toward a high-strength concrete with a dense cementious matrix that contains an irradiated plastic additive. Cement samples containing various combinations of cement binder and plastic content were prepared; compressive strength tests showed that for all cement binder types, the addition of high dose irradiated plastic resulted in increased compressive strength as compared to the strengths achieved by samples with regular, non-irradiated plastic. This suggests that irradiating plastic at a high dose is a viable potential solution for gaining some of the strength back that is lost when plastic is added to concrete. To assess the internal structure of the samples and gain some insight into what aspects of their chemical compositions' contributed to the observed strength differences, a microstructural analysis -- consisting of XRD, SEM, and X-ray microtomography -- was performed. XRD analysis showed that various differences in C-S-H and C-A-S-H phase formation from the addition of both irradiated plastic and mineral additives helped to form high-density phases that contributed to higher relative strengths. BSE analysis showed that an increased alumina content among fly ash samples helped to form the high-density phases that contributed to higher relative strength among the fly ash samples, as evidenced through a ternary phase diagram. X-ray microtomography showed that the addition of high dose irradiated plastic consistently contributed to a decrease in segmented porosity, indicating that irradiated plastic may have acted as a pore-blocking agent. The results presented clearly show the benefit of using irradiated plastic as a concrete additive for improved compressive strength. By partially replacing Portland cement with a repurposed waste material, this design, when scaled to the level of mass concrete production, could contribute to reduced carbon emissions and provide a long-term solution for waste plastic storage. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Page 37 blank. Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 33-36).

A suitable method of overhead distribution at the Converse Rubber Shoe Company

Tue, 01 Jan 1918 00:00:00 GMT

A suitable method of overhead distribution at the Converse Rubber Shoe Company White, George R Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Business and Engineering Administration, 1918.; Includes bibliographical references (leaf 42).

Magnetobiology and possible implications for awareness research

Sun, 01 Jan 1967 00:00:00 GMT

Magnetobiology and possible implications for awareness research Gevins, Alan Stuart Massachusetts Institute of Technology. Dept. of Humanities. Thesis. 1967. B.S.; Includes bibliographical references.

Buffalo Forge Company : a case study in sales engineering management.

Sat, 01 Jan 1977 00:00:00 GMT

Buffalo Forge Company : a case study in sales engineering management. Bond, Michael Joseph Thesis. 1977. B.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.

The building of honor for an important scientific university

Wed, 01 Jan 1908 00:00:00 GMT

The building of honor for an important scientific university Schmidt, Frederic Becker Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1908.; Accompanying drawings held by MIT Museum.

Software tools for experimenting with cellular automata

Fri, 01 Jan 1982 00:00:00 GMT

Software tools for experimenting with cellular automata Choi, Inwhan Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING; Bibliography: leaf 22.

Early stage product design process : a case study of an educational building kit

Sun, 01 Jan 2017 00:00:00 GMT

Early stage product design process : a case study of an educational building kit Alper, Natalie B A Science, Technology, Engineering, and Math (STEM) kit for the assembly of a lamp was created to encourage children's interest in mechanical and electrical engineering. To ensure the lamp was intuitive and fun to use, user testing was conducted. As the user interface (UI) for the lamp was designed and developed, tests were conducted with users using a variety of prototypes ranging from paper, cardboard, and plastic to PowerPoint storyboards on the computer. By incorporating user testing throughout the process of identifying possible button layouts as well as proper lamp proportions, a final intuitive UI with a single panel of buttons was converged upon. This UI utilized one button to switch through the four possible light modes instead of having a separate button for each mode. This UI will be employed in a future prototype that will be further tested with children in the intended age range. These tests will utilize 3D printed pieces for the base and buttons, and will incorporate all the PCBs and LEDs that are intended for use in the final product. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 35).

Gelsight robotic fingertip

Sun, 01 Jan 2017 00:00:00 GMT

Gelsight robotic fingertip Liu, Melody Grace Tactile sensing is integral in robotic manipulation, enabling robot hands to identify objects and explore the environment. The gelsight tactile sensor designed in MIT CSAIL is able to reconstruct the surface topography of objects up to submicron accuracy. This thesis is focused on the integration of the gelsight tactile sensor into the MIT Team's gripper for the 2017 Amazon Robotics Challenge. The design of the sensor is dependent on the three manipulation primitives in the gripper platform: scooping, grasping, and suction. This paper discusses the primitives and the sensory inputs they would require to create more precise manipulation models. We then propose a gelsight tactile sensor around those primitives, creating a design that can recover shear, deflection, compliance, and contact area information. Lastly, we implement some of the image processing to recover deflection by creating a mapping between image points and ground truth vicon values, producing an 75% accuracy rate within a distance threshold, a value that can be improved with increased measurements and better image processing techniques. Further work focuses on image processing for shear, compliance, and contact area, to be integrated into the overall design for the 2017 ARC gripper. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 28).

Design of educational engineering projects fabricated with the laser-cutter and CNC wire bender

Sun, 01 Jan 2017 00:00:00 GMT

Design of educational engineering projects fabricated with the laser-cutter and CNC wire bender Sayre, Larkin V The aim of this investigation is to design educational project enclosures for engineering students at MIT that utilize the laser-cutter, CNC "DiWire" wire bender and various other mechanical engineering tools. Introducing students to the laser-cutter and wire bender gives them hands-on experience with some exciting mechanical tools for fabrication to supplement their courses in electrical engineering. The key objective of this investigation is finding a cheap, safe, professional-looking, easy-to-manufacture setup that teaches students the desired concepts and gives flexibility for Professor Leeb to integrate novel engineering projects into his classes. The second section of this design project is the creation of a soldering iron holder made using components bent on the DiWire. Many design iterations are carried out before settling on the final design and material choice. The soldering iron holder is then incorporated into a larger electrical engineering project. This larger project is a speaker that students put together and house in a special enclosure. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, February 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references.

Pump-sizing software tool for small-scale solar-powered irrigation systems in water-scarce conditions : a case study in Uttar Pradesh

Sun, 01 Jan 2017 00:00:00 GMT

Pump-sizing software tool for small-scale solar-powered irrigation systems in water-scarce conditions : a case study in Uttar Pradesh Sung, Christina Two small-scale well-irrigation systems in rural Uttar Pradesh which had previously operated via diesel pumps have been modified to operate via solar pumps. The regions where the irrigation systems are located are currently experiencing drought, and the well of one of the systems runs dry during irrigation. It is hypothesized that the 3HP solar pumps installed in the systems are larger than necessary, and are overdrawing from the water supply. A pump-sizing software tool was developed in Excel Spreadsheets to model and analyze the two specific systems, as well as to aid in future pump-sizing for long-term water sustainability for similar types of irrigation systems operating in water-scarce conditions. It was determined that the 3HP pumps installed in the irrigation systems are not unreasonably large for the crop water demands, and that under drought conditions, it was inevitable that continued irrigation at the two sites studied would eventually lead to well depletion and is thus unsustainable. Focusing on pump-sizing for these types of irrigation systems in water-scarce conditions may not be as effective for water sustainability as adjusting the irrigation systems and methods at the sites. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 20).

Robustness of adaptive control systems to unmodeled dynamics : a describing function viewpoint

Sun, 01 Jan 2017 00:00:00 GMT

Robustness of adaptive control systems to unmodeled dynamics : a describing function viewpoint Sharma Subedi, Chandan Recently, it was shown that a standard model reference adaptive controller modified with a suitably tuned projection algorithm ensures robustness (global boundedness) of the overall adaptive system to a class of unmodeled dynamics with minimal restrictions. However, extensive first-principle based arguments and/or analysis of the parameter trajectory is employed. An alternative to such analysis, albeit approximate, is to use the well-known Describing Function (DF) method. In doing so, the analysis of the robust adaptive control problem becomes tractable and resembles that of familiar and classical linear stability analysis. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 43-44).

Device for mechanical plotting of power/speed curves for a D.C. motor

Sun, 01 Jan 2017 00:00:00 GMT

Device for mechanical plotting of power/speed curves for a D.C. motor Warner, Jace Cali The relationships between power, speed, and torque in a direct current motor are often not intuitive to students based on functionality of modern dynamometers. Previous work in a 1998 master's thesis by Peter T. Lee built a device to mechanically demonstrate the torque/speed relationship for engineering students. This thesis expands that work to prototype a modified device to show the power/speed relationship utilizing a mechanical multiplier. Speed and torque output are converted into linear motions along perpendicular axes, and power is output as their product. This thesis summarizes the design and construction of a first prototype of such a mechanical dynamometer device that can be used in teaching demonstrations. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 23).

A design for a sewerage system for Weymouth, Massachusetts

Fri, 01 Jan 1915 00:00:00 GMT

A design for a sewerage system for Weymouth, Massachusetts Bibolini, Alejandro; Cohen, Jacob Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1915.

An experimental investigation of the minimum Reynolds' number for instability in water jets

Fri, 01 Jan 1960 00:00:00 GMT

An experimental investigation of the minimum Reynolds' number for instability in water jets Viilu, Andrus Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Aeronautical Engineering, 1960.; MIT copy bound with: Nonlinear control system for the control of yaw angle of an aircraft / Jason L. Speyer. 1960.; Includes bibliographical references (leaf 14).

Experiments on explosive mixtures

Wed, 01 Jan 1890 00:00:00 GMT

Experiments on explosive mixtures Glidden, John W; Loring, Atherton Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1890.; MIT copy bound with: A study of the balancing of the drivers of the eight-wheel locomotive by means of counterweights / Wm. Parker Flint.

Design and test of an automatic chucking, drilling and ferruling machine

Fri, 01 Jan 1915 00:00:00 GMT

Design and test of an automatic chucking, drilling and ferruling machine Kingsbury, Edward J; Roy, Kenneth W Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1915

A library for a large university like Harvard

Mon, 01 Jan 1900 00:00:00 GMT

A library for a large university like Harvard Ford, George B. (George Burdett), 1879-1930 Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1900.; MIT copy bound with: A public library for a city of 40,000 inhabitants / Rudolph J. Clausen. Accompanying drawings held by MIT Museum.

The conversion of an Otto cycle into an Atkinson cycle

Fri, 01 Jan 1937 00:00:00 GMT

The conversion of an Otto cycle into an Atkinson cycle Ferrary, Ferdinand F Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1937.; MICROFICHE COPY AVAILABLE IN ENGINEERING.; Includes bibliographical references (leaf [20]).

Acquaintances and contacts of Franklin Roosevelt : the first 86 days of 1934

Fri, 01 Jan 1960 00:00:00 GMT

Acquaintances and contacts of Franklin Roosevelt : the first 86 days of 1934 Rosenthal, Howard L Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Economics and Social Science, 1960.; MIT copy bound with: A collective bargaining model / by George Lermer [1960]; Includes bibliographical references (leaf 57).

Heavy nuclides in cosmic radiation.

Wed, 01 Jan 1969 00:00:00 GMT

Heavy nuclides in cosmic radiation. Hallock, Geoffrey Gaddis Massachusetts Institute of Technology. Dept. of Physics. Thesis. 1969. B.S.; Bibliography: leaf 41.

A study of Nb3(Al.75Ge.25) and V3Au superconducting tunnel junctions.

Mon, 01 Jan 1973 00:00:00 GMT

A study of Nb3(Al.75Ge.25) and V3Au superconducting tunnel junctions. Gregory, James Allen Massachusetts Institute of Technology. Dept. of Metallurgy and Materials Science. Thesis. 1973. B.S.; MICROFICHE COPY ALSO AVAILABLE IN SCIENCE LIBRARY.; Leaves with plates and diagrams unnumbered (20 leaves).; Includes bibliographical references.

Effects of conjugated oligoelectrolytes on cell transformation

Sun, 01 Jan 2017 00:00:00 GMT

Effects of conjugated oligoelectrolytes on cell transformation Fernandez, Nicholas (Nicholas J.) A key step in genetic engineering is the delivery of genetic material into the cell. Increasing bacterial cell transformation efficiency can help advance an area of scientific research with a wide range of applications. Previous work has demonstrated conjugated oligoelectrolytes (COEs) neutralize the surface charge of bacterial cells and increase membrane permeability, which can potenitally increase their competence in accepting exogenous DNA. This study tested the effect of the COE DSSN+ combined with electroporation on the transformation of Escherichia coli cells. Multiple experiments with varying concentrations of DSSN+ and varying voltages provided bacterial colony growth and transformation efficiency data for each of the testing conditions. A repeatable experimental procedure is outlined with comments on potential future work that can help better understand and improve cell transformation. While this study cannot make any statistically significant claim from the data, the results of the experiments still provide necessary insight into the effect of DSSN+ on cell transformation. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 28).

A payload-centric approach towards resilient and robust electric-propulsion enabled constellation mission design

Sun, 01 Jan 2017 00:00:00 GMT

A payload-centric approach towards resilient and robust electric-propulsion enabled constellation mission design Graham, John Kyle Recent studies have shown that distributed spacecraft missions, or constellations, can offer similar performance to monolithic satellite missions for lower cost and less risk. Additionally, recent developments in and implementation of electric propulsion (EP) technologies further the case for the use of constellations because they enable operational possibilities otherwise unavailable to satellites with chemical thrusters by reducing costly fuel requirements. Through more efficient fuel usage, EP allows for wide-scale rendezvous of satellites for refueling/maintenance as well as constellation reshuffling and orbit raising to recover system performance after losing a satellite. With these constellation-wide maneuvers at an operator's disposal, distributed space-craft missions will be able to operate longer and will have more flexibility to adapt and respond to malfunctions in the constellation. This thesis analyzes the performance gains of distributed spacecraft missions that utilize EP by analyzing satellite constellations at both microscopic and macroscopic levels - first, by understanding how payloads of different types, when combined with higher power requirements for EP systems, impact and influence an individual satellite's design and mass, and then exploring how, within a 2D orbital plane, this individual satellite can use its greater endurance to move within the network and influence entire constellation performance. Together, these different levels of understanding provide the necessary framework to effectively design and analyze robust and effective constellations, regardless of mission type. A case study of the OneWeb global internet mission demonstrates that use of currently available electric propulsion technologies can save up to 3000 kg per plane over chemical thrusters and can completely eliminate the need for spare satellites for lifetime failure rates of up to 10%. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 187-189).

Open wheel racecar steering

Sun, 01 Jan 2017 00:00:00 GMT

Open wheel racecar steering Gerasimoff, Steven (Steven A.) The steering system of a rear wheel drive open wheel racecar is the only directional control the driver possesses while driving. Steering linkages must be carefully designed to allow cars to navigate turns without exhausting the driver. Motorsports vehicles are designed to make tight turns while maximizing tire grip to maintain higher velocities in corners. Steering geometry must be optimized not only for car performance, but also to maximize driver comfort and improve the "feel" of the vehicle. In competitive motorsports, the steering system is critical to vehicle performance: an incorrectly designed system can at best cost a few fractions of a second on the track, and at worst cause severe driver injury. In the Formula SAE competition, student teams are tasked with designing and manufacturing all subsystems of a racecar for an annual competition while balancing safety, cost, and performance. This thesis will introduce fundamentals of steering system design, and will document in detail the design, analysis, manufacture, and testing of the 2017 MIT FSAE steering system. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 36).

A framework for collecting data : revising sensor synchronization methods

Sun, 01 Jan 2017 00:00:00 GMT

A framework for collecting data : revising sensor synchronization methods Gonzalez, Sara (Sara H.) Data collection is frequently carried out in research, as well as in industry for purposes ranging from quality control to assessing system limits. However, several complications may arise to hinder optimal data collection and analysis, including synchronization of different data types from a variety of sensors. A benchtop model was designed with the primary goal of understanding human-spacesuit interactions through the collection and analysis of force, pressure, and internal kinematics data. This thesis addresses shortcomings in the setup that led to difficulty in data analysis and synchronization and presents a revised framework for collecting these data. A system was designed such that the start of each trial of data collection can be synced across the three types of sensors: a load cell, a pressure mat, and inertial measurement units. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 29).

Designing Course 2 assignments to emphasize practical engineering applications

Sun, 01 Jan 2017 00:00:00 GMT

Designing Course 2 assignments to emphasize practical engineering applications Edwards, Allison (Allison R.) MIT's educational philosophy, mens et manus, stresses the importance of providing students with both a conceptual and practical understanding of engineering. This thesis explored the development of design guidelines for creating assignments for introductory Course 2 classes that better emphasize the practical side of this educational mission. These design guidelines were identified by redesigning one case study 2.004 laboratory assignment, the tall building vibration lab. From student feedback on this case study assignment, the successful features of this redesigned assignment could be identified and used as guiding principles for the design of future assignments. Student reviews of the case study assignment indicated that the most promising feature of this assignment was the fact that it was structured as an interactive story set in a specific engineering project context. This feature may be used as an initial guiding design principle for the creation of other Course 2 assignments. More work must be done to test and develop these design guidelines further and to understand how to create assignments that teach practical applications of engineering while still allowing students to efficiently complete their graded work. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.

Finite Element Analysis on the skin properties affecting wound closure

Sun, 01 Jan 2017 00:00:00 GMT

Finite Element Analysis on the skin properties affecting wound closure De Maillé, Austin (Austin C.) This thesis presents a Finite Element Analysis investigation on the properties of skin that affect skin wound closure and scar formation. It begins with an in depth literature review of mammalian studies and computer simulations of skin wounds, providing a better understanding of the mechanics of skin during wound healing. Details are then provided into the construction, simulation, and data processing of a finite element model in which wound shape, wound contraction forces, and subcutaneous tissue resistance are all varied. Two major conclusions can be drawn from these simulations. (1) When comparing rectangular, square, and circular wounds of the same initial wound size, rectangular wounds close fastest and circle wounds close slowest. (2) Subcutaneous tissue appears to be physically connected to the underlying dermis. Increased resistance/stiffness forces by subcutaneous tissue lead to less tissue contraction, however the relationship between skin deformation and subcutaneous resistance has not been determined. It appears that as skin displacement increases, subcutaneous tissue stiffness exponentially increases. Additional simulations must be completed to confirm this theory. Other factors affecting skin contraction, including skin thickness and Langer lines, have yet to be tested and should be pursued in future studies. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 32-33).

Force control in flapping foils using in-line motion and passive pitch

Sun, 01 Jan 2017 00:00:00 GMT

Force control in flapping foils using in-line motion and passive pitch Grant, Fiona (Fiona R.) Flapping foils are the standard engineering approximation for many biological actuators in air and water, but these devices typically provide propulsion at the cost of parasitic oscillatory forces. The addition of in-line motion to a flapping foil trajectory can improve the control of the fluid force. Previous work has shown that by actuating the heave, surge, and pitch motions of a foil and iteratively optimizing the results, the lift and thrust forces on the foil can be precisely and independently controlled. In this thesis, the same experiment is modified to include solely passive pitch to determine if similar force control performance can be achieved without either a fully actuated pitch motion or an optimization process. In the new experiment, the fluid forces naturally drive the pitch motion for most of the flapping cycle, until the foil reaches a maximum pitch angle, which is set with a mechanical stopper. The hydrodynamic forces are recorded for a range of trajectories that include forwards in-line, backwards in-line, and no in-line motion. Lift force control improves over that of the fully actuated system, but thrust force control is not achieved to the same level of performance. Further work can be done to determine whether simple pitch angle control can be implemented to improve thrust force control without the addition of the optimization process. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 39).

Redesign of FlexLab cantilever beam for reduced resonance frequencies and increased damping

Sun, 01 Jan 2017 00:00:00 GMT

Redesign of FlexLab cantilever beam for reduced resonance frequencies and increased damping Harmon, Christopher (Christopher T.) Hands-on learning remains a key aspect of the educational path through MIT. It provides the practical experience and real-world tie-in that theoretical study and analysis alone could not uphold. Thus, it is necessary to ensure that a lack of lab resources, space, and time do not present barriers to prospective students. As such, the portable FlexLab/LevLab module serves to bring laboratory teaching beyond the lab. This paper presents the results of efforts to redesign the FlexLab portion's cantilever beam to meet two design goals. First of all, that the frequency of the second natural mode of the beam fall below 100 Hz. Second, that the beam's damping is increased such that the first peak gain is within an order of magnitude of the surrounding gain. After testing, a new beam geometry and damping mechanism that satisfied both goals is proposed. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 40).

Models to predict dynamic response of motorcycles with a outrigger & trailer

Sun, 01 Jan 2017 00:00:00 GMT

Models to predict dynamic response of motorcycles with a outrigger & trailer Harris, Jimmie D., V It is of interest, especially in the developing world, to explore the feasibility of using motorcycles in applications beyond personal transport. In particular, adding an outrigger wheel to a motorcycle may increase its capabilities for heavier duty operations like road haulage and agricultural mechanization. This thesis examines the feasibility of using motorcycles for low-speed high-weight towing and outrigger like attachments. Two different configurations will be evaluated. The first looks at how the addition of a large trailer affects the turning ability, stability, and power delivery of a motorcycle. The trailer is modeled as a single body system consisting of a single axle and large load and to attached by a definable hitch mounted near the rear wheel of the motorcycle. The second case examines the attachment of an outrigger like structure. This is of interest to farm like vehicles that wish to simply support a tool over a set of wheels using a motorcycle Here the motorcycle and third wheel are modeled as a single body system with a long simply supported beam that has a load applied from the forces due to the side car. A MATLAB model detailing the ability, stability, and power delivery of a motorcycle was created to determine these performances. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 30).

Exploring assistive technology solutions and universal design

Sun, 01 Jan 2017 00:00:00 GMT

Exploring assistive technology solutions and universal design Green, Erica (Erica L.) Creating devices that take those with limited physical abilities into account can make everyday tasks easier for everyone to perform. During this project, a user with restricted fine finger dexterity was considered in the design of a product that assists people with opening sealed packages. The primary user was first interviewed about his needs and limitations. After initial research was performed, the team ideated and completed basic sketches of products concepts. The user was again consulted for impressions and feedback about the variety of ideas, and the team continued by focusing on one broad concept and fleshing out the details. Once several different mock-ups of the chosen concept were made, they were presented to the user. His feedback then informed the design of a second round of prototypes. User testing will be completed before settling on a final design. The final product will be presented at the Design for America Spring Critique on May 18th, 2017. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 21).

Investigating the coefficient of restitution of major league baseballs

Sun, 01 Jan 2017 00:00:00 GMT

Investigating the coefficient of restitution of major league baseballs Hesslink, David In the middle of the 2015 Major League Baseball season there was a sudden increase in home run rate. Such a sudden league-wide change is difficult to explain, and many baseball pundits suggested that a "juiced" or altered baseball was the culprit. In this thesis, large scale coefficient of restitution (COR) testing is performed on baseballs from before (2014) and after (2016) the alleged change. No evidence is found to suggest that the baseball was altered between 2014 and 2016. The investigation nevertheless revealed telling properties of the coefficient of restitution. First, it was largely found that baseballs from both years fell within the COR specifications of Major League Baseball (between 0.514 and 0.578). Second, the COR is revealed to be a noisy quantity in that the same baseball can exhibit differences in COR on the order of 0.01. Third, most of the variation between baseballs' COR comes from being manufactured on different days in the plant and thus being packaged in different boxes. Additionally, an unexpected fatigue in the strike plate used in the test apparatus is found to have affected the COR measurements for the first 200 trials. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 23-24).

Creating a materials library for mechanical engineering students

Sun, 01 Jan 2017 00:00:00 GMT

Creating a materials library for mechanical engineering students Das, Patricia (Patricia Adalia); Mo. Roget A material can enhance or distract from the end-user experience and is an important decision for designers. As such, material libraries exist to provide designers with a hands-on resource to understanding materials beyond just data sheets. When we took 2.009, a mechanical engineering capstone class, we found it difficult to decide which materials to use. Thus, in this work, we sought to create a materials library under an engineering context for student product designers to use. To understand how material libraries function and which materials would best suit the collection, we benchmarked three physical and one virtual material library. We also sought input from those involved in product design classes, such as past students, Professor Wallace who teaches 2.009, and Pappalardo shop staff who support the students in their creations. We also looked at past receipts to supplement our knowledge as well as looked at distributors and what they offered to expand our selection. Our six main categories of materials were: woods, metals, composites, polymers, fabrics, and Smooth-On products. The material libraries key criteria were to be well organized, portable, and useful. We went through several design sketches before deciding on utilizing a modular wire rack so we could place dividers and shelves as necessary. A coding system was also implemented that included main categories and subcategories with associated colors to help with the user experience of quickly locating, using, and returning. Each material comes attached with information and a more complete overview is located in an information packet. While this first version the materials library was met with excitement, it is by no means complete. As such, there are also a number of ways to improve the experience and the collection. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 47).

Introducing engineering and design to homeschooled middle and high school students

Sun, 01 Jan 2017 00:00:00 GMT

Introducing engineering and design to homeschooled middle and high school students Huynh, Hannah (Hannah E.) In this thesis, the researcher organized and taught an introduction to engineering and design course to her local middle and high schools. Inspired by an industry experience and MIT resources, she developed a curriculum that incorporated interactive activities and culminated into a design challenge for these homeschooled students. She surveyed their interests in and perceptions of engineering and design before and after this introductory course, and the students were 81% percent more interested in engineering and 80% in design after having taken the course. Both student and parent feedback, formally through surveys or informally through conversations, shared about the positive influence this course has had on bringing exposure of engineering and design to the students. This program achieved the researcher's goal of exciting students to consider pursuing engineering and design. The researcher hopes to continue this program in the future with some revisions like cutting back some taught material to allow for more build time or developing a separate more specific and advanced engineering course for students already interested in engineering. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 101-102).

Design of a recycling method for treated aluminum fuel

Sun, 01 Jan 2017 00:00:00 GMT

Design of a recycling method for treated aluminum fuel Cox, Wesley (Wesley T.) An experimental study was performed to characterize the waste byproduct of a high energy density aluminum fuel in order to identify an effective recycling method. A sample of fuel waste was generated and viewed under a scanning electron microscope. The sample was then subjected to an energy-dispersive X-ray spectroscopy analysis which focused on points of interest identified by the scanning electron microscope. The results of the imaging and analysis showed that gallium and indium, which are used in the fuel manufacturing process, are randomly scattered around the reacted aluminum waste. These metals were found in their elemental form, meaning they do not react alongside the aluminum fuel. As such these metals can be recovered by suspending them in water and using mass differences to isolate them from the remainder of the waste. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 14).

Quantitative analysis of 200 meter track times

Sun, 01 Jan 2017 00:00:00 GMT

Quantitative analysis of 200 meter track times Corts, Brandon (Brandon E.) Using male, varsity, division 3 collegiate track and field results from the past decade, critical coaching decisions such as optimizing meet scheduling, targeting efficient training programs to mimic, and identifying potential performance-influencing factors on athletes can be made more easily. To come to these conclusions, 200-meter race times were normalized using seasonal athlete improvement factors and wind data to identify at which facilities athletes tended to run faster times and what factors make those facilities fast. It can be concluded that the variation in banked track and field facilities makes the banked-to-flat track conversion factor implemented by the NCAA in 2012 is potentially too harsh for athletes to compete on some banked indoor tracks compared to others. The data also has the potential for many other applications such as identifying the highest quality training programs, analyzing conversion factors and facility speed for races other than the 200-meter dash, and applying similar principals to variations in swimming facilities. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 19).

Learning while producing : the use of games in teaching statistical process control

Sun, 01 Jan 2017 00:00:00 GMT

Learning while producing : the use of games in teaching statistical process control Coffrin, Jane S Statistical Process Control is used daily in factories throughout the world and its use improves the quality of manufacturing parts. But while it is widely used, it is not widely understood by the workers implementing these techniques. Without a strong understanding of Statistical Process Control, it can be misused and cause more harm than if it wasn't implemented. Correctly implemented Statistical Process Control, however, can improve the quality of the implemented parts. To remedy this, a game was designed to teach people with limited exposure to manufacturing and/or statistics an understanding for how Statistical Process Control is used in manufacturing. This game implements a mathematical model that takes factors within the game and raises or lowers the variance based on in-game factors then random gives a number based on the expected values. A paper prototype for this game was made and tested with students from multiple majors, then was turned into a python program. A pre-test and a post-test were developed and then used to test the base knowledge of the participants as well as their learning after playing the game. From the observations of participants playing the game and from their pre-test and post-test results a set of next steps was developed to make this a more viable game for teaching workers about Statistical Process Control. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 26).

Automating structural stress analysis : beam deflection, shear, and moment diagram generator for single and multi-span beams

Sun, 01 Jan 2017 00:00:00 GMT

Automating structural stress analysis : beam deflection, shear, and moment diagram generator for single and multi-span beams Jacobucci, Cody A new tool has been developed with Aurora Flight Sciences to automate stress analysis of beams under loading. It is a Microsoft Excel based tool to be consistent with Aurora's other analysis tools and analyst preference, and is coded in Visual Basic. The tool can generate the shear, moment, and deflection diagram of a single span or multi-span beam in less than 10 seconds for any combination of edge constraints and applied loads, as well as output the reaction force at each support. The tool can also analyze beams that change material or shape after reaching a support to account for changes in longer beams across the airframe. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 87).

Development of a sandcasting process for an Atlantic Marine Engine

Sun, 01 Jan 2017 00:00:00 GMT

Development of a sandcasting process for an Atlantic Marine Engine Joba-Woodruff, Kyle The Atlantic Marine Engine, designed and manufactured by Lunenburg Foundry of Lunenburg, Nova Scotia, is a historically significant gasoline marine engine from the beginning of the 20th century. The Atlantic and other similar engines transformed the American and Canadian fishing industries with their power and reliability. A project to recreate a historic J model, single cylinder, two-cycle "make and break" engine is ongoing at MIT's Pappalardo Laboratory by a number of students. This thesis will focus on making progress towards a completed engine with the design and fabrication of the engine base. The fabrication will continue to use a traditional sandcasting process, but will explore the viability of using computer-aided design and manufacturing (CAD/CAM) processes to make high quality patterns out of high-density polyurethane foam. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 26).

Review of flapping foil actuation and testing of impulsive motions for large, transient lift and thrust profiles

Sun, 01 Jan 2017 00:00:00 GMT

Review of flapping foil actuation and testing of impulsive motions for large, transient lift and thrust profiles Kotidis, Miranda Flapping foils were tested to produce large, transient forces in still water. These swift, onetime strokes take advantage of added mass/inertial effects and large, stably attached vortices to avoid delay due to the realization of a jet wake for propulsion [1]. Previous work has produced trajectories, characterized by heave and pitch, for which the lift and thrust profiles were confirmed. Two trajectories were reproductions from previous studies, and the lift and thrust force profiles match those produced before. An additional trajectory was tested, which produced a much different profile. All three trajectories included a smooth sweeping motion, but the third trajectory included a subsequent sharp change in pitch. This sharp change in pitch, or pure rotation, produced sharp force peaks and oscillations in thrust, in addition to force peaks from the sweeping motion which resembled the other two trajectories' profiles. Further work includes confirming the lift and thrust coefficients and exploring additional trajectories or optimizing current trajectories for producing large, transient forces for underwater vehicle propulsion and control. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 17).

Effectiveness of active cooling on torque performance for prosthestic applications

Sun, 01 Jan 2017 00:00:00 GMT

Effectiveness of active cooling on torque performance for prosthestic applications Chen, Ava E Motors used to actuate powered prostheses generally under-utilize their torque capacity due to thermal limitations of the windings. This thesis investigates the effectiveness of increasing the rate of heat transfer away from the windings in order to enable running motors at higher currents than their rated maximum levels, thus raising this torque saturation limit. Simulation models and physical prototypes based on the RCTiger 100KV U8 brushless outrunner motor were built to observe the temperature of the windings as constant current was applied to the motor. The addition of a fan-based active cooling system allowed the motor to run at 142% of its maximum continuous current rating for up to 56 seconds before winding temperatures exceeded 550 C, and limited temperature increase in simulation to 26' above ambient temperature when the full 35A stall current was applied for one second. Although the simplified circuit model was not able to fully capture nonlinear thermal behavior of the motor, simulations were able to predict approximate heating time constants and time duration before windings reached threshold temperature for current ranges 5- 15A. Experimental and simulation results support the hypothesis that active cooling enables motors to run at their full torque potential for short periods of time, which holds promise for the use of cooling mechanisms in prosthetic applications. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 53-54).

Characterizing the failure of parachute seams : the impact of stitch concentration and strain rate on ultimate tensile strength

Sun, 01 Jan 2017 00:00:00 GMT

Characterizing the failure of parachute seams : the impact of stitch concentration and strain rate on ultimate tensile strength Karafillis, Pavlina Parachutes are commonly used in space mission landings. With increasing payloads, parachutes are getting larger, bearing larger loads and operating at faster speeds. Designing these devices requires a knowledge of aerodynamics, fluid flow, and the mechanical properties of cloth. A brief overview of the basics of parachute design are described. There are many possible failure modes, but catastrophic failures are caused by failures at the weakest point of the parachute, the seam. Seams are characterized by a seam efficiency, a percentage of the strength of the cloth used to stitch the seam together. In this study, seams and cloth were tested to failure on an Instron 5582 to experimentally determine their respective Ultimate Tensile Strengths (UTS). The ratio of the seam UTS to the cloth UTS was used to determine seam efficiency. Results indicated no clear relationship between strain rate and seam efficiency in the range tested. However, a strong relationship between stitch concentration and seam efficiency was established. A best fit curve was developed and with an an R2=0.80. In order to better understand the failure mode, the open source Matlab function Ncorr was also used to provide a visualization of the strain on the coupons during testing. The results of the digital correlation analysis performed by Ncorr are also reported, and indicate the importance of transverse and shear strain in causing catastrophic failure. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 29).

Freestanding public toilet design and location in Boston and Cambridge : a comparative case study

Sun, 01 Jan 2017 00:00:00 GMT

Freestanding public toilet design and location in Boston and Cambridge : a comparative case study Castaños, Emma Isabel This paper explores urban sanitation provision in the United States via a comparative case study of the freestanding public toilets in Boston and Cambridge. The research attempts to capture the influence of municipal institutions and local actors on public toilet design and location, and further attempts to assess to what degree the resulting design and location meet project stakeholders' own communicated priorities as well as anticipated user needs. This is an IRB approved project that engaged stakeholders through interviews and further corroborated online research with toilet block site visits. The study concluded that the Portland Loo design, while it lacked many amenities of the Automatic Public Toilet design, it is a more robust and suitable toilet for a high-demand and high-risk urban environment. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 57-59).

Exploration of configurations of wave energy converters to mechanically drive a seawater uranium harvester

Sun, 01 Jan 2017 00:00:00 GMT

Exploration of configurations of wave energy converters to mechanically drive a seawater uranium harvester Cao, Cyndia A Nuclear power accounts for about 20% of the electricity generated in the United States today [29], but conventional reserves of terrestrial uranium are estimated to be depleted within the century [19]. Fortunately, an estimated 4.5 billion tonnes of uranium exists as ions in the ocean [281, and a system of adsorbent polymers has been designed to extract the uranium. A proposed machine to harvest seawater uranium, the Symbiotic Machine for Ocean uRanium Extraction (SMORE), is fixed to a floating wind turbine and requires 550 kW to power four nets of shell enclosures containing the adsorbent and the chemical processing required to remove the uranium and reuse the polymer [161. Given the high energy density of ocean waves, this thesis explores the potential of wave energy converters to provide the power requirements of SMORE. Each net requires 92 kW of power, or about 1100 kNm to drive continuous movement at 0.087 rad/s. This thesis found that harnessing that amount of power would require a heaving buoy of 11.5 m diameter and 1 m height, though the large geometry and range of motion caused structural concerns. In contrast, a pitching buoy of 4.7 m diameter and 2 m height could provide the same amount of power, and the structure could be more easily reinforced with only one moving body. Various configurations of pitching buoys are discussed as well. While this thesis defined a first order approximation of a future system, the modeling of realistic sea states and several mechanical optimizations need to be explored further. The integration of some electronics to power the chemical processing tanks and optimize the response control of the buoy may also provide benefit at a small increase in cost. Using a wave energy converter reduces not only the power load on the turbine, but also may decrease the incident wave loads and stabilization requirements of the turbine [13]. Further cost analysis is required, but a future implementation of this wave energy converter could add great value to both the uranium harvesting system and floating wind turbine. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 97-99).

Analysis of human coordination patterns between a younger and older age group during the timed up and go test

Sun, 01 Jan 2017 00:00:00 GMT

Analysis of human coordination patterns between a younger and older age group during the timed up and go test Barillas, Danielle (Danielle Celeste) An experimental study was performed to understand lower limb movement patterns between older and young adults, and to explore a new metric of coordination. Lower limb and torso movement in an older and younger population was captured using both IMU sensors and an optical tracking system. Only data from the optical method was processed and analyzed for this thesis. The participants executed several trials of a Timed-Up-and-Go test (TUGT), a 10 meter Walk Test (10MWT), and a Standing Balance Test (SBT). This paper specifically analyzed data from seven of the participants when executing the TUG test. The Relative Coordination Metric (RCM) from Hip to Knee and from Knee to Ankle was briefly explored for one subject from each age group. Several qualitative differences in motion were seen between the younger subject and the older subject for the Hip-Knee RCM, while similarities were identified for the Knee-Ankle RCM. The TUG time for the younger age group (M = 11.48s, SD = 1.26s) and the older age group (M = 12.06s, SD = 0.69s) was also compared and it was found that they were significantly different (t =1.998, p = 0.017). Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 25).

Analysis & characterization of a flow thermo-electrochemical cell for power generation & heat convection

Sun, 01 Jan 2017 00:00:00 GMT

Analysis & characterization of a flow thermo-electrochemical cell for power generation & heat convection Booeshaghi, Ali Sina In this thesis, I analyzed and characterized a new flow thermo-electrochemical cell that generates power from waste-heat, while in parallel convecting this heat away from the source. I also reviewed previous research on the topic of thermo-electric energy generation, governing physics behind thermo-electrochemical energy generation, actual device fabrication, device testing, results, and applications of this technology. Thermo-electric devices (TE devices) exhibit the thermo-electric effect, where temperature gradients and material properties work in tandem to drive electron transfer at electrode surfaces, thereby generating electricity. For example, a typical sold-state TE device such as a bismuth telluride TE device, can generate up to 0.300 mV/K [31]. New reseach has emerged [25, 26, 14] focusing on liquid-based thermo-electrochemical (TEC) cells that take advantage of the temperature dependence of oxidation/reduction chemical reactions to generate electricity. One of the major benefits of these TEC devices over traditional TE devices is a much higher S, = 1.5 mV/K; another is the low cost of manufacturing, making them promising for commercial applications. The new TEC device that I fabricated and studied utilizes a flowing electrolyte instead of a stationary electrolyte. With this new configuration, and a heated boundary condition, I studied both the energy generation and convective heat transfer capabilities of the flowing electrolyte TEC cell. Numerically I obtained a maximum power output and heat transfer coefficient for the TEC cell of Pmax = 2.6 [mu]W and h = 340 W/m²K which corroborates well with the experimentally found value of Pmax = 2.0 [mu]W and h = 450 W/m². K. If employed in data centers, as a device for CPU cooling, with the given power output I found that a 100,000 ft² data center can generate about 21.96 MWh of energy, which at a cost of 0.20 $/kWh can save a data center about 5,000 $/year. More generally, the application of this technology in locations where waste-heat is prevalent, will allow for energy recycling and consequent cost savings. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 53-55).

Modeling and fabrication of an Atlantic marine engine

Sun, 01 Jan 2017 00:00:00 GMT

Modeling and fabrication of an Atlantic marine engine Andrews, Gordon Moseley P Three-dimensional CAD models for the one-lunger Atlantic marine engine cylinder and manifold were developed from original engineering drawings, and the corresponding patterns and core molds for casting designed. The viability of CNC milled high-density foam for fabricating complex casting patterns and molds was demonstrated with the Atlantic engine cylinder and manifold. The modeling processes presented in this paper can be applied to other projects in documenting historical components and machinery, and the CNC fabrication techniques can be applied generally for rapid pattern and mold generation. From a historical perspective, the development of the models, patterns and physical castings presented in this paper are one step in restoring the heritage of the one-lunger marine engines and bringing life to the first Atlantic engine of the 2 1st century. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 44).

Effects of cross-link and myosin motor concentrations on active muscle gel contraction time and extent

Sun, 01 Jan 2017 00:00:00 GMT

Effects of cross-link and myosin motor concentrations on active muscle gel contraction time and extent Babcock, Joseph M. (Joseph Michel) The cytoskeleton is a crucial network of actin filaments that gives the cell its shape, assists in organelle organization, and allows for cell movement. Active muscle gels are a class of materials that that mimic the functionality of the cytoskeleton. Utilizing myosin II motor proteins to initiate contraction events in actin networks, active muscle gels have the unique potential of acting as microscopic actuators. Two challenges currently faced by active muscle gels are their slow contraction time and weak contraction forces. This thesis seeks to achieve contraction events in a lab setting and observe how contraction speed and extent varies with the concentration of myosin motors and alpha-actinin crosslinks. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 26).

Fabrication of an 1897 Herreshoff marine steam engine

Sun, 01 Jan 2017 00:00:00 GMT

Fabrication of an 1897 Herreshoff marine steam engine Agosto, Priscilla (Priscilla M.) A 19th century Herreshoff marine steam engine was developed using a combination of traditional and modern fabrication methods. Background on Nathaniel Herreshoff, his connection to MIT and the Herreshoff Manufacturing Company was provided. The process for selection of appropriate steam engine with the input from the Francis Russell Hart Nautical Museum at MIT was explored. CAD models were developed from the original drawings from MIT's Haffenreffer-Herreshoff Collection. Pattern making options, casting, sand types and machining practices were explored and analyzed. Furthermore, a blueprint for a single-semester course in advanced fabrication methods for MIT 2.007 Senior Undergraduate Apprentices was proposed. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 46-47).

A parametric study of the repeatability of 3D printed LEGO®-like mechanical couplings

Sun, 01 Jan 2017 00:00:00 GMT

A parametric study of the repeatability of 3D printed LEGO®-like mechanical couplings Kurfess, Rebecca (Rebecca Ann) Parts made using Additive Manufacturing (AM) are limited in size to the build area of the 3D printer being used. Embedded elastically averaged locators can be used to join AM parts into assemblies, resulting in a piece larger than the build area, yet the design and placement of these locators must enable sufficient accuracy and repeatability of the couplings. In this thesis, locator design was formulated and verified using contact area, interference, and stiffness of the couplings as the design variables. A LEGO®-like coupling design was printed out of ABS on an Afinia H480 Fused Deposition Modeling (FDM) printer and measured with a ZEISS MICURA Coordinate Measuring Machine. The accuracy of each coupling was determined by measuring the radial misalignment between the base and the top of the coupling, and the repeatability of each coupling was determined by calculating the standard deviation of the radial misalignment after decoupling and re-coupling five times. The couplings were displayed accuracy on the order of 10 [mu]m and repeatability on the order of 1 [mu]m. Varying interference, contact area, and stiffness had a statistically insignificant effect of accuracy. Varying interference had a statistically insignificant effect on repeatability, increasing contact area increased repeatability by 0.75 [mu]m, or 15%, and increasing increased repeatability by 0.57 [mu]m, or 12%. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 43-44).

Finite element method with hierarchical domain decomposition : enabling experimentally relevant mesoscale models

Sun, 01 Jan 2017 00:00:00 GMT

Finite element method with hierarchical domain decomposition : enabling experimentally relevant mesoscale models Malhotra, Laura (Laura A.) Mesoscale materials such as metallic glass present a difficult modeling challenge because their time and length scales place them in a gap where neither continuum mechanics nor quantum mechanics-based models are computationally tractable. The STZ dynamics model is a mesoscale approach to modeling this class of materials. However, modeling the response of such amorphous metals to deformation is still very computationally expensive. As meshes get larger, the runtimes of the mesoscale models get much longer, particularly in three dimensions; in fact, the computation is currently not efficient enough to run on experimentally relevant length scales. This thesis focuses on a hierarchical domain decomposition method that will be combined with other strategies to speed up the current models. A hierarchical mesh was generated, and then used to make the finite-element portion more efficient. The runtime and error of this accelerated model were then studied in order to assess the usefulness of the technique. The results show a mediocre runtime speedup that could become more impressive after optimization. More importantly, error drops off superlinearly with distance from the strained element, so accuracy is not sacrificed when using the accelerated method. Therefore, hierarchical domain decomposition can be used with the other speedup strategies to enable larger mesoscale simulations. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 23).

Dynamic optimization of two methods of the long jump

Sun, 01 Jan 2017 00:00:00 GMT

Dynamic optimization of two methods of the long jump Mo, Stacy (Stacy M.) In this thesis, I analyzed, modelled, and optimized two different techniques of the long jump: the hitchkick and hang. Using video data, I made a dynamic model of both techniques, then created a cost function that took torques and angles into consideration to simulate physical limitations. Using a function minimizing optimizer, trajectories were simulated over a range of torque limits and angle penalties. Over the course of 292 simulations, we found that the hitchkick technique improved jump distances more than the hang technique, improving by up to 34.65% with an average of 7.7% while the hang technique increased jump distance by a maximum of 30.21%, with an average of -15.89%. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 45).

Fuel economy of a turbocharged, single-cylinder, four-stroke engine

Sun, 01 Jan 2017 00:00:00 GMT

Fuel economy of a turbocharged, single-cylinder, four-stroke engine McCoy, Colleen (Colleen M.) Agriculture is the main source of livelihood for a majority of India's population. However, despite the number of workers, the yield and the yield of principal crops in India is much lower than that in developed nations. One of the reasons for this is the lack of farming mechanization in India. One of the common ways to run farming equipment is by using a single-cylinder, four-stroke diesel engine. Diesel engines can be turbocharged in order to make them more efficient for less cost. A method has been found to turbocharge a single-cylinder diesel engine by adding an air capacitor to form a buffer between the intake and exhaust strokes. This thesis analyzes how the size and heat transfer of the air capacitor for this turbocharged diesel engine are correlated to engine performance and fuel economy. According to the modeled engine, a 3.0 liter capacitor had better peak power and fuel economy at high loads and speeds than a 2.4 or 1.25 liter capacitor. Additionally, forced convection cooling on the capacitor using a fan allowed the intake air density to increase, and the engine to have better fuel economy than the . However the peak power and fuel economy of the modeled naturally aspirated engine was better than the turbocharged engine for speeds below 2500 rpm. The general trends from the model were reflected in the experimental data. The forced convection increased cooling, and improved the intake air density. However, it was difficult to make any confident recommendations about the fuel economy based on the experimental data. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 56-57).

Design and analysis of a battery pack enclosure for Formula SAE

Sun, 01 Jan 2017 00:00:00 GMT

Design and analysis of a battery pack enclosure for Formula SAE Merrow, Henry (Henry W.) This thesis documents the design and analysis of the enclosure for the high voltage battery pack which powers the Model Year 2017 MIT Formula SAE racecar. The battery pack is custom designed and built with six modules of 144 Samsung INR18650-25R lithium-ion cells each. Each component of the enclosure is analyzed to ensure structural integrity and optimized to reduce mass of the battery pack. The enclosure is able to secure the modules during sudden accelerations or decelerations from crash scenarios, allows for air flow to cool the cells, and allows for convenient serviceability of the modules. The final mass of the enclosure, at 8.5 kg, results in an overall battery pack mass of 59.5 kg, 76% of the mass of the Model Year 2016 battery pack. All components of the enclosure have been manufactured, and the assembly process with the modules and high voltage electronics has been tested and verified. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 41).

Feasibility of translating earthships in Africa and future design considerations

Sun, 01 Jan 2017 00:00:00 GMT

Feasibility of translating earthships in Africa and future design considerations Nabahe, Sade Kailani Earthships are passive solar buildings with renewable power, water harvesting, and sewage systems, designed to be off grid with minimal reliance on public utilities, and use recycled and natural materials. Due to high initial capital cost and resources needed, earthships have primarily been implemented in developed countries. However, the self-sufficiency earthships offer through their subsystems presents an opportunity for resource-constrained environments. Three earthship projects have been developed in Africa, each serving a unique purpose and overcoming different obstacles. Through earthship design principles, technical reports, and lessons learned from each project, this paper aims to outline design considerations for those who are interested in implementing an earthship in Africa. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 35-36).

Design and manufacturing of a benchtop thermoforming machine

Sun, 01 Jan 2017 00:00:00 GMT

Design and manufacturing of a benchtop thermoforming machine Owusu-Akyaw, Akwasi The following work details the design and fabrication of a tabletop thermoform machine with the goal of making this machine cheaper than the ones on the market, yet able to fulfill specific requirements. These functional requirements include creating parts that have dimensions within .05" of the original part; thermoforming plastics that range between a 3" x 3" and 12" x 12" size; and having the ability to heat the plastic to at least 150°C in order to thermoform plastics such as polycarbonate. In addition, this machine had to be simple to manufacture and use. In order to achieve these requirements, a top to bottom drape forming architecture with a four bar linear slider and carriage, was constructed. In order to constrain the plastics of different sizes, two similar, modular wooden plates were used such that the plastic was held in between them via t-nuts and screws. When the user clamps the plastic onto the carriage, he or she slides the carriage upwards to an oven that radiates heat via nichrome wire on a mica sheet. Once the desired temperature is reached, the user then slides the carriage down onto a vacuum box platform, where a mold is present, and forms the plastic over the mold. While that happens, a negative pressure is applied inside the box via a standard commercial vacuum, so that the plastic adheres more closely to the mold. For the testing process, this work focuses on two manufacturing strategies for thermoforming parts: heating the air to the glass transition temperature before thermoforming, and heating the plastic to the glass transition temperature before thermoforming. Once this test was performed, the dimension of each plastic part was examined in order to see if the tolerance levels were reached. In addition, this test determined whether or not there was a statistical significance between the qualities of parts made by either of these processes. In the end, the thermoform machine was only able to reach an average tolerance of .07" for the created parts. In addition, there was no statistical significance between the part qualities of either one of the tested manufacturing processes. Some of the main reasons behind this include having an ineffective vacuum box and clamp design issues, which will be focused on in the future iteration of this project. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Page 39 blank. Cataloged from PDF version of thesis.; Includes bibliographical references (page 38).

Design of creative narrative and technical systems for an immersive multimedia nighttime spectacular show

Sun, 01 Jan 2017 00:00:00 GMT

Design of creative narrative and technical systems for an immersive multimedia nighttime spectacular show Parrish, Garrett V The goal of this thesis is to explore the design process for the creative and technical components of a nighttime spectacular show. As spectacular shows are a unique art form with unusual narrative structures and conventions and complex technical systems involved in their implementation, they present an intriguing case study for the design process. There exists almost no academic literature on the process used to effectively design and construct large scale entertainment experiences as virtually all of those projects are carried out in the private sector and any innovations required to complete the projects are documented in patents as opposed to academic publications. With a specific narrative goal in mind and distinct derivative works, a twelve minute show narrative was written and designed. Furthermore, the various production elements (set, lighting, audio, music, and control systems) were also designed and constructed to serve as an explicit implementation of the creative narrative. The show consists of three main 'acts', with individual beats and scenes, each of which fulfills a certain set of creative and technical design requirements. The practical producing of this show is exempt from this thesis as the focus is on the creative narrative and technical systems design processes. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references.

Hydrodynamics of magnet-coil actuated robotic fish

Sun, 01 Jan 2017 00:00:00 GMT

Hydrodynamics of magnet-coil actuated robotic fish Petelina, Nina The hydrodynamics of two robotic fish were analyzed: a low cost toy robotic fish for developing live fish experimental techniques, HEXBUG(TM) Aquabot, and a low cost robotic fish for swarm robotics experiments, Scuba Fish. Both of these robotic fish use a magnet-coil actuation method in order to create caudal fin motion. A velocity imaging technique,, Particle Image Velocimetry (PIV), was used in order to characterize the wake structure created by the tail beat. Both robotic fish were towed through water as a high speed camera recorded the movement of seeding particles around the caudal fin, which are illuminated with a laser. From 2D PIV and 3D Synthetic Aperture PIV experiments for the Aquabots it has been identified that the discrete tail beat from the bang bang control creates vortex pairs at each start or stop motion of the caudal fin. Moreover, the wake structure from the shark Aquabot tail beat creates a wake structure similar to live dogfish sharks. Since the design of the Scuba Fish allowed more control over the motion of the tail, an additional ramp pwm caudal fin control was designed and tested in order to analyze the wake from a continuous tail beat. The results show that the vortex shedding pattern created by the pwm ramp design is different from the bang bang cases; the method creates a negative vortex ring with a small vortex pair at the end of the motion. This suggests that further designs of a continuous control have to be investigated in order to achieve a more real fish-like swimming behavior. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 44).

Causes and analysis of failures in in-situ microscopy observation for the characterization of scaling in membrane distillation membranes

Sun, 01 Jan 2017 00:00:00 GMT

Causes and analysis of failures in in-situ microscopy observation for the characterization of scaling in membrane distillation membranes Polanco, Pedro (Pedro D.) In membrane technology at large, fouling limits membrane performance and membrane lifespan. In the case of reverse osmosis membrane distillation (MD) involving fluid mixtures of inorganic elements, inorganic foulants build up on membrane surfaces, and reduce the flux of fluids across a membrane. Inorganic fouling can degrade the quality of water produced by membrane distillation. In order to counteract the effects of membrane fouling, potentially costly procedures like intense chemical cleaning or membrane replacement are necessary. Some theory suggests that, instead of reacting and adhering to membrane surfaces, salts tend to bulk nucleate in solution, and then deposit on high energy surfaces, like metal heat exchangers and hydrophilic reverse osmosis membranes. This is in contrast to the theory that crystals first deposit on the membrane surface to cause fouling. A solution of Na2SO4. and CaCl, was pumped across a membrane at 70°C at 2.6 GPM (9.8 LPM) to observe membrane fouling. Using an in-situ camera, fouling on a membrane distillation surface was captured to characterize the nature of MD fouling. Due to failures in heat distribution across the solution and system leaking, no fouling on the membrane surface was observed. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 27).

Design of a mechanical system for tillage tool depth control on small farm tractor

Sun, 01 Jan 2017 00:00:00 GMT

Design of a mechanical system for tillage tool depth control on small farm tractor Porter, Elizabeth (Elizabeth C.) Tractor implements increase the risk of injury by destabilizing the tractor, and therefore they must be designed with caution and mechanical integrity. Tillage tool attachment systems must be designed to determine a tool's maximum depth into the soil and withstand the resulting forces from the soil. The following paper presents a design for an attachment system that incorporates a self-locking rack and pinion jack, load-bearing sliding surfaces, and rack clamp that is used to secure the cultivator sweep. The design is evaluated for deformation and deflection at the maximum theoretical loads using Finite Element Analysis. The design successfully minimizes deflection, but exhibits stresses higher than the material yield stress in a small area. After slight modifications to the bar attachment structure in a future design iteration, the tillage tool design will be ready to test in the field. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 34).

Design of soft-body robot with wireless communication for leak detection in large diameter pipe systems

Sun, 01 Jan 2017 00:00:00 GMT

Design of soft-body robot with wireless communication for leak detection in large diameter pipe systems Saleeby, Kyle Scott Water leaks pose a major problem of efficiency and cost to municipalities and industries that cover significant area. While current commercial methods to address these problems do not provide convenient or low cost methods to detect leaks, a soft-body pipe leak detection robot has been developed to traverse small, 50mm diameter water pipe systems. This robot has proven to be effective in small diameter pipes, but its scalability for large diameter pipes is unknown. The focus of this thesis is to scale up the leak detection robot for 300mm diameter pipes and fabricate a robot prototype. In particular, the relationship between the shape of the robot and its maneuverability was explored, such that it was designed to passively travel through the pipe, driven by water flow. The robot was designed to successfully pass through changes in pipe diameter, pipe bends, and through partially clogged regions. To detect and distinguish pipe leaks from other debris in the pipe, two sensors were integrated in the robot. Experimental testing was conducted with the robot to verify functionality of its leak detection sensors. Supporting electronics were also implemented to wirelessly charge and communicate with the robot. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references.

Material modeling and sensor characterization for optimizing footpad force sensing array

Sun, 01 Jan 2017 00:00:00 GMT

Material modeling and sensor characterization for optimizing footpad force sensing array Studebaker, Seth with the ultimate goal of assisting the elderly and disabled with fall prevention and mitigation as well as providing athletes with critical data for training. The force sensing footpad, originally developed for use on the MIT Cheetah robot, integrates lightweight pressure sensors and a urethane rubber, Smooth-On's Vytaflex@ 20, to sense force in both the normal and shear directions. In previous work, cylindrical footpads with a single pressure sensor of differing heights and diameters were tested by applying displacements to the material. The experimental force and voltage from the pressure sensor were recorded. The thesis aims to provide a Finite Element Analysis (FEA) model in Abaqus that accurately simulates and models the footpad sensors and is validated by the physical experimental results. While previous work had been done to model and simulate the footpad using FEA, little was known about the properties of the Vytaflex@ material and a Neo-Hookean model based on coefficients for a silicone rubber was used to model the footpad. In order to provide accurate simulations, the thesis seeks to determine the best hyperelastic constitutive model to describe the material. Uniaxial tensile, uniaxial compression, planar tension, and volumetric compression tests were performed to determine the hyperelastic material model of the rubber. The Odgen n=2 material model was determined to be the best fit for the data and was used to describe the material properties in the Abaqus simulations. Abaqus models were created to represent the various cylindrical footpads and simulations were run using Abaqus's dynamic explicit analysis. Stress data from the simulation results was then converted to a voltage using an effective sensitivity and intercept adjustment factor. The effective sensitivity and intercept adjustment factor were adjusted until the simulation results matched that of the experiments. Using these constants, the stresses inside the footpad can now be determined from the voltage readings of the pressure sensor. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 54).

Design of housing for stove use monitors (SUMs) to measure adoption/

Sun, 01 Jan 2017 00:00:00 GMT

Design of housing for stove use monitors (SUMs) to measure adoption/ Waller, Erica (Erica M.) Billions of people around the globe rely on solid fuels such as wood or charcoal to heat their homes and cook their meals which negatively impacts health as well as the environment. Improved cook stoves negate these problems but are often not used over time. Stove use monitors (SUMs) are attached to improved cook stoves to track adoption rates. Three basic designs were generated of a housing for the SUM. They were analyzed by considering material choices, manufacturing options, and customer needs. Thermal images were taken of an improved cook stove in use to measure temperatures at key locations around the stove. It was found that the sides and handles of the stove attain a maximum temperature of above 150 °C (300 °F), and the feet and base of the stove below that. It was determined the best course of action is to design a housing for the base or feet of the stoves and use resin casting and later injection molding as production needs increase. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 27-28).

Design of a Formula SAE electric powertrain

Sun, 01 Jan 2017 00:00:00 GMT

Design of a Formula SAE electric powertrain Wanek, Brian (Brian J.) The design requirements for the new electric powertrain were the ability to deliver the peak power of 80kw allowed by rules and meet the mass goal of 23kg. Rear wheel independence needed to be maintained either through a multi-motor design or a differential, but with vehicle performance in mind. Stiffness of the mounting system was another goal, as the previous design had lateral deflections larger than deemed acceptable. Along with system design requirements, various components and packaging options were considered. Preliminary design and estimation coupled with fundamental engineering rational focused the design to a particular setup. In parallel with system design, analysis was performed to select materials, geometry, bearings, and hardware. Load cases were analyzed to determine how FEA simulations would be set up. Failure modes checked were primarily yield conditions, but stiffness of the mounting plates was also analyzed to ensure the system met the max deflection goal of 0.005". The final design included a single three phase electric motor capable of up to 100kW peak with a limited slip differential, and a mass reduction of almost 45% over the previous powertrain, meeting the mass goal. Eccentric rings allow for easy chain tensioning. A simple 6 bolt mounting system makes the self-contained unit easy to remove from the frame, and overall stiffness is improved from the previous design. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 21).

The development of a multistage centrifugal pump for use in flow chemistry

Sun, 01 Jan 2017 00:00:00 GMT

The development of a multistage centrifugal pump for use in flow chemistry Yue, Brian (Brain J.) Flow chemistry is an emerging approach to chemical synthesis in which chemical processes are performed on reactants as they continuously flow through reactors. In order to drive such flows, low flow rate, high pressure pumps are used. The standard pump in use is the displacement pump. However, it tends to be expensive and produces a discontinuous flow. The goal of this investigation is to prototype a miniature multistage centrifugal pump and assess whether or not such pumps can perform in flow chemistry applications in the place of displacement pumps. This thesis explores the design features implemented in the development of this pump and how they contributed to its performance as pertaining to use in flow chemistry. Specifically, the pump was designed to be comprised of modularly stackable pump stages and to be thermochemically stable, operating without the use of dynamic seals. Ultimately, the device designed succeeded in being modularly stackable and in operating without dynamic seals. However, the target pressure rise per stage was not fully met. Moreover, testing of the pump revealed a high sensitivity in flow rate to changes in generated pressure head. Thus, it is not yet deemed a viable alternative to the current standard of displacement pumps. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 44).

Design and implementation of cantilever probe holder for tapping mode atomic force microscopy

Sun, 01 Jan 2017 00:00:00 GMT

Design and implementation of cantilever probe holder for tapping mode atomic force microscopy Yu, Jennifer, S.B. Massachusetts Institute of Technology In this thesis, I present the design and implementation of a novel cantilever probe holder that is capable of tapping mode operation. The probe holder is implemented in a previously designed high-speed, large-range atomic force microscope (AFM). This AFM used a cantilever probe holder that was only capable of contact mode operation, placing limitations on imaging speed and increasing the risk of probe tip damage. Therefore, the focus of this thesis presents the improved design of a cantilever probe holder that actuates and utilizes probe dynamics. This will allow for more flexible and sustainable use of the AFM system. Additionally, two versions of this improved design are developed for operation in air and in liquid. Classical plate theory, finite element analysis (FEA), and non-parametric system identification are used to validate the structure dynamics of the cantilever probe holder. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 71-72).

Analysis and optimization of passive knee prosthetic design parameters over varying cadences

Sun, 01 Jan 2017 00:00:00 GMT

Analysis and optimization of passive knee prosthetic design parameters over varying cadences Swaminathan, Krithika The need for effective prostheses is prevalent worldwide, and is especially dire in developing countries and low-resource settings. The MIT GEAR Lab is addressing this gap through the ATKnee, a low-cost, passive prosthetic knee that employs the use of spring and damper components to replicate the knee torque of the able-bodied human knee. In this study, we build upon prior work to optimize the components used in the ATKnee by accounting for results from field-testing. We first develop an inverse dynamics model to confirm understanding of previous work. We then use a genetic optimization algorithm to optimize parameters across different walking speeds and various spring-damper configurations. The best fit, as measured by the highest R2 value, is obtained when a viscous damper is active during the first dissipative phase (b*11 ), a friction damper is active during the second dissipative phase (b*/20 ), and an additional friction damper is active throughout both phases (b*/0). We make the suggestion that b*/0 = 0.084, b*/11 = 0.008, b*/0 = 0.183, gives the most optimal passive system knee torque with the engagement and disengagement timings teng = 51.3%, tdis1 = 64.2% for the first damper, and teng2 = 86.1%, tdis2 = 95.2% for the second damper. We find that the parameters are robust to subject body mass, but show a positive correlation with walking speed. We conclude that while we are able to suggest an optimized parameter set that includes higher order dampers, it will be important to investigate the effects of cadence, as well as to study the joint torques at the hip, which is further from the foot. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 38-39).

Design and analysis of a turbocharged single cylinder diesel engine intake system for increased power output and transient response

Sun, 01 Jan 2017 00:00:00 GMT

Design and analysis of a turbocharged single cylinder diesel engine intake system for increased power output and transient response Ward-Santos, Orlando Small displacement, single-cylinder diesel engines have many applications in developing countries such as small-powered agricultural equipment, water pumps, and other power sources. Research has shown that the power of a turbocharged single-cylinder engine can match that of a larger displacement multi-cylinder, naturally aspirated engine, at a fraction of the cost. The valve timing mismatch that occurs when turbocharging a single cylinder engine is solved by adding a large volume air intake as a buffer for the pressurized air. This thesis explores the design, methodology, and testing of modifying the additional air intake to passively varying its volume during operation. Mechanical design of the variable volume air capacitor is established. Next, the experimental setup is discussed. Finally, both steady state and transient experimental results are discussed. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 35).

Analysis of materials properties of thin film structures for thermoelectric and thermophotovoltaic applications

Fri, 01 Jan 2010 00:00:00 GMT

Analysis of materials properties of thin film structures for thermoelectric and thermophotovoltaic applications Baum, Brian K Metal-organic chemical vapor deposition (MOCVD) was used to grow InAsP graded layers and AlAs/GaAs superlattices for materials studies related to thermophotovoltaics and thermoelectrics respectively. High resolution x-ray diffraction (HRXRD) was used to determine the As concentration in each of the InAsP layers. Arsenic concentration was found to vary linearly with the percentage of AsH3 in the reactive gas flow up to 60 % deposited, and had an asymptotic relationship for higher incorporated concentrations. Higher growth temperatures reduced As incorporation. Transmission electron microscopy (TEM) images were used to determine layer thicknesses. The growth rate of InAsP layers was found to be independent of growth temperature and the percentage of As. Superlattice samples with 0 %, 5 %, 10 %, and 20 % variations in the superlattice period were grown via MOCVD and analyzed using HRXRD. The intensities of the satellite peaks were found to decrease and broaden with increasing variation in the period length and disappeared completely in samples with up to 10 % variation. Thermal conductivity measurements performed using an optical pump-probe technique showed lower thermal conductivities for samples with greater variation. The irregularity of the superlattice period is believed to enhance the structure's ability to impede phonon propagation. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2010.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 45-46).

In search of martensite : titanium-tantalum shape-memory alloy

Fri, 01 Jan 2010 00:00:00 GMT

In search of martensite : titanium-tantalum shape-memory alloy Disko, Jeffry There is a broad range of life-saving medical implants and devices that rely on the shape-memory (SME) and superelastic properties of various nickel-based alloys [8]. Unfortunately, there is also serious concern about the toxicity of nickel. Titanium based shape-memory alloys have been noted as potentially non-toxic replacements of the more traditional, nickel-based shape memory alloys. In this thesis I present research concerning the potential of SME-capable titanium-tantalum alloys to replace Ni-based alloys in medical implants. A method for heat treatment of Ti -Ta alloys of varying compositions to induce formation of martensite was developed. Heat-treated alloys were then tested for SME and superelastic behavior by means of hot oil recovery tests and were characterized through optical microscopy. Metallographs of some of the samples were taken throughout the processing and testing procedures in order to directly observe changes in microstructure.. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2010.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 47-48).

Semi-solid redox flow battery

Fri, 01 Jan 2010 00:00:00 GMT

Semi-solid redox flow battery Duduta, Mihai materials used in Li-ion batteries and the design and functioning of a redox flow cell. The use of Li-ion battery materials offers significant increases in energy and power density (200 Wh/kg compared to 25-35 Wh/kg for current commercial vanadium redox batteries). The implementation of a redox flow system allows for energy to be stored outside the cell and for the power and energy of the battery to be decoupled. A proof of concept is achieved by successful cycling of anode and cathode suspensions under intermittent flow conditions. The importance of materials' stability to cell life, energy and power densities is discussed. The high energy densities may enable the use of the proposed system in a variety of application, ranging from grid-level storage to fully electric charge. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2010.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 53).

Edible photonic crystals tunable within the visible regime

Fri, 01 Jan 2010 00:00:00 GMT

Edible photonic crystals tunable within the visible regime González, Xavier (Xavier R. González Barrios) An experimental study was performed to design and fabricate an edible photonic crystal made of alternating layers of food grade titanium dioxide and agar that is able to selectively reflect wavelengths of light within the visible spectrum and allow for dynamic color changes through the tuning mechanism of swelling its agar layers with the addition of edible solvents. After doing a literature search to discover which materials were available to create this edible photonic structure, a trial and error process was conducted using deposition and film thickness characterization techniques to optimize the physical and optical characteristics of the layers composing the photonic structure. The materials selected for the layers in the structure yield a high refractive index contrast, which allows for high reflectivity with a reduced amount of total layers. The multilayer stack can be designed to reflect particular wavelengths by selecting the thickness of the layers accordingly. Thin film characterization took place through the use of profilometry, ellipsometry, and atomic force microscopy. The feasibility and practicality of two manufacturing techniques, spin-coating and RF-sputtering, were analyzed in the process of learning how to assemble an edible multilayer stack for molecular gastronomy applications. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2010.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 50-52).

The natural interface between bone and tendon : SEM observations of the enthesis in an ovine model

Fri, 01 Jan 2010 00:00:00 GMT

The natural interface between bone and tendon : SEM observations of the enthesis in an ovine model Reese, Willie Mae The present study investigates the naturally occurring interface between bone and tendon using scanning electron microscopy. The micrographs revealed a cartilaginous layer, 100 to 400 [mu]m thick apposing bone, that contained cells varying in size and shape as a function of their location in this cartilaginous layer. Further investigation is required to conclude whether these cells are undergoing further differentiation during development of this graded layer. This study found the interface between bone and the cartilaginous layer to be interdigitated, which may explain why injuries at the bone-tendon interface are comparatively rare. Also, the cartilaginous layer was revealed to be substantially mineralized. A somewhat higher concentration of calcium and phosphorus was observed near the interface with the apposing bone that gradually diminished into the cartilaginous layer. These findings support the four zone description of the bone-tendon interface established by others using histological methods. However, further research is suggested to resolve other questions about the observed sub-micrometer morphologies of the bone-tendon interface. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, June 2010.; "May 2009." Page 47 blank. Cataloged from PDF version of thesis.; Includes bibliographical references (pages 28-29).

Radiation damage quantification in elemental copper using Wigner energy storage

Sun, 01 Jan 2017 00:00:00 GMT

Radiation damage quantification in elemental copper using Wigner energy storage Carter, Ki-Jana (Ki-Jana B.) Radiation damage in materials can cause critical components in fission and fusion reactors to fail with potentially catastrophic consequences. Radiation damage quantification is essential for understanding, predicting, and preventing such failures. The current unit of radiation damage, displacements per atom (DPA), is not a measurable quantity, and it is known to be an inaccurate measure of radiation damage. This project aims to quantify radiation damage accurately and measurably by characterizing the storage of energy in radiation-induced material defects, known as Wigner energy storage. In order to gain an atomistic understanding of radiation damage, the irradiation and calorimetry of elemental copper were simulated using molecular dynamics code. A custom defect analysis script was used to determine the energy stored as a function of irradiation energy and defect type. Wigner energy peaks were clearly visible in the calorimetry data, indicating that Wigner energy measurement is a plausible technique for quantifying radiation damage. Future work should focus on achieving more realistic heating rates and measuring Wigner energy storage experimentally using fast scanning calorimetry. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 55-58).

A combined radiographic and time-of-flight method for zero-knowledge warhead verification

Sun, 01 Jan 2017 00:00:00 GMT

A combined radiographic and time-of-flight method for zero-knowledge warhead verification Hecla, Jake J A novel means of combined spectroscopic and radiographic zero-knowledge warhead verification has been developed and investigated using Monte Carlo simulations. This verification approach, henceforth called "epi-ZK," uses time-structured beams of epithermal neutrons to verify weapon isotopics and geometry without creating or transmitting meaningful information about the device design. This method seeks to remedy information security and hoax resistance issues inherent in previously proposed zero-knowledge verification methods such as fast neutron radiography with preloaded detector arrays and NRF based methods. By using a combination of epithermal neutron radiography and time-of-flight analysis, the epi-ZK method achieves sensitivity to subtle isotopic and geometric hoaxes, while preserving a high level of information security. Results using a MCNP5¹ model of the verification setup on the "Black Sea Object" pit geometry as well as a speculative HEU implosion weapons design indicate that the method would be highly effective, even using existing research reactor or accelerator neutron sources. This method of verification therefore presents a viable means of verification for weapons previously excluded from treaties such as ST ART due to a lack of information-secure means of assuring device authenticity. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.; "June 2017." Cataloged from PDF version of thesis.; Includes bibliographical references (pages 49-51).

High-fidelity simulations of transverse electric waves propagating through Alcator C-Mod

Sun, 01 Jan 2017 00:00:00 GMT

High-fidelity simulations of transverse electric waves propagating through Alcator C-Mod Major, Maximillian R This project represents an attempt to model the propagation of microwaves into Alcator C-Mod's plasma in high fidelity and with a reduced number of degrees of freedom. The success of this endeavor would accelerate progress within the field of fusion energy, as simulations of C-Mod's plasmas, or other plasmas in general, can be run more quickly while still maintaining their accuracy. The main procedure involves producing simulations within COMSOL that use mode numbers based on a power spectrum of waves at 4.6 GHz. These simulations are then overlaid to model how the waves will propagate as a function of position, plasma density, and local flux. Future work could focus on verifying the accuracy of the simulations when compared to data acquired from C-Mod as well as ensuring the run-time of the simulations is indeed faster than other methods. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 28).

Diverting steam created in a nuclear reactor to produce electricity more economically

Sun, 01 Jan 2017 00:00:00 GMT

Diverting steam created in a nuclear reactor to produce electricity more economically Shifflet, Natalie J Nuclear power is not as economically competitive as other electricity generation methods. To increase the use of nuclear power, nuclear power must become more profitable. A way to accomplish this is by storing superfluous energy during times of low energy prices to be used when the electricity price is greater. This could be done by varying the load to the turbine by diverting steam from before the turbine while the nuclear reactor runs at full power. In order to understand this project idea of diverting steam to a thermal storage to increase profit, literature on nuclear systems, steam turbines, and regulations was analyzed. It was found that between 40% and 75% of steam can be diverted from the secondary system of a pressurized water reactor. This number depends on the specific reactor and turbine system. The energy of the steam will be stored through a thermal storage method that can be directly or indirectly connected to the diverted steam. Each set-up comes with its advantages and disadvantages as adding a heat exchanger loses work, but would make regulatory considerations easier. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 22-24).

Transition metal-facilitated C-C and C-F bond forming

Sun, 01 Jan 2017 00:00:00 GMT

Transition metal-facilitated C-C and C-F bond forming Perry, Ian B. (Ian Brooks) Chapter 1. Copper-Catalyzed Asymmetric Addition of Olefin-Derived Nucleophiles to Ketones A copper (I) catalyzed coupling olefins and ketones has been developed for the diastereo- and enantioselective generation of homopropargyl alcohols bearing vicinal stereocenters. This method allows for the generation of enantioenriched tertiary alcohols with a high degree of functional group compatibility. The utility of the process is further illustrated by a large scale synthesis with extremely low catalyst loading as well as the late stage modification of several pharmaceuticals. Chapter 2. Copper-Catalyzed Enantioselective Addition of Styrene-Derived Nucleophiles to Imines We describe the catalytic generation of amines bearing vicinal stereocenters with a moderate degree of diastereoselectivity. The stereoselective hydrocupration of an unactivated olefinic component is followed by nucleophilic addition of the organocuprate to an N-phosphinoyl protected imine. The mild and general process tolerates a broad-range of functionality, and the process was shown to be successful at a gram-scale synthesis. Chapter 3. Palladium-facilitated Regioselective Nucleophilic Fluorination of Aryl and Heteroaryl Halides. The preliminary findings regarding an aryl and heteroaryl halide fluorination process facilitated by palladium as a reagent is described. Stoichiometric studies illustrate the utility of the method in producing aryl fluorides with unprecedented regioselectivity, and preliminary studies into the fluorination of five- and six-membered heteroaryl bromides are described. Halogen atom substitution as a route to irreversible oxidative addition of aryl and heteroaryl halides is discussed. This strategy may serve to facilitate the fluorination of particularly problematic heteroaryl bromide and chloride substrates. Thesis: S.B., Massachusetts Institute of Technology, Department of Chemistry, 2017.; Cataloged from PDF version of thesis. "June 2017."; Includes bibliographical references.

Design of PolyMOCs and the synthesis of crosslinkers for the BASP platform

Sun, 01 Jan 2017 00:00:00 GMT

Design of PolyMOCs and the synthesis of crosslinkers for the BASP platform Park, Jiwon Victoria In Chapter 1, two stepwise assembly strategies for the integration of metal-organic cages (MOCs) into polymers were explored. The first strategy creates Block Co-PolyMOCs (BCPMOCs), which feature the integration of MOCs into block copolymers (BCPs). In the first assembly step, BCPs functionalized with a bispyridyl ligand on the chain end undergo Pd induced MOC assembly. In the second step, microphase separation of BCPs is induced, introducing a physical cross-link between the star polymers and producing the desired BCPMOC networks in the bulk or gel state. In the second strategy, another orthogonal interaction is explored to create a different type of polyMOC. In this case, poly(methyl acrylate) (PMA) homopolymers are synthesized from initiators featuring a diene or dienophile on one end and functionalized with a bispyridyl ligand on the other end. Diels-Alder (DA) cycloaddition is used in the second step to create a polyMOC network. Given the functional diversity of MOCs, both strategies should enable access to materials with a wide range of properties and applications. Chapter 2 outlines the synthesis of norbornene macromonomers (MMs) with varying anchor groups and crosslinkers that are stimuli-sensitive for the brush-arm star polymer (BASP) drug delivery platform. Variation of MM anchor groups modifies the rate of propagation of ring-opening metastasis polymerization (ROMP), while the design of crosslinkers that are acid- and photo-labile contributes to the expansion of a wide-ranging library of crosslinkers for drug loading and release. The brush-first ROMP polymerization strategy allows for the synthesis of BASPs for single drug or multiple drug combinations. Thesis: S.B., Massachusetts Institute of Technology, Department of Chemistry, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 33-34).

A cost optimization of solar-powered, drip irrigation systems

Sun, 01 Jan 2017 00:00:00 GMT

A cost optimization of solar-powered, drip irrigation systems Doan, David, S.B. Massachusetts Institute of Technology This thesis presents a design and cost optimization for solar-powered, drip irrigation systems. Historical irradiance data and crop consumption data are considered and modelled during these design steps. A cost optimization is utilized in order to determine low-cost, optimum configuration that meets the required water consumption rate of a given crop. In this case, Jalgaon, India is used as an example to determine the configuration and cost per acre for solar-powered, drip irrigation systems for sunflowers, tomatoes, and barley. These configurations consisted of five 310 Watt solar panels coupled with a 5m³ water buffer, three 295 Watt solar panels coupled with a 5m³ water buffer, and three 320 Watt solar panels coupled with a 4m³ water buffer, respectively. These systems are projected to cost $4,600, $3,870, and $3,750, respectively. The results of this study show the value of a system optimization of solar-powered, drip irrigation systems. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 79-81).

Design and analysis of a Stewart-platform-based six-axis load cell

Sun, 01 Jan 2017 00:00:00 GMT

Design and analysis of a Stewart-platform-based six-axis load cell Ruiz, Maria Rosa, S.B. Massachusetts Institute of Technology In this work, a six-axis load cell based on the geometry of a Stewart platform was developed. Its geometry and functional requirements were motivated by the needs of robotic limbs designed to be attached to human workers to support them in typically unergonomic positions. The sensor can measure forces and torques in six degrees of freedom, and can stably support the worker in various hanging positions while still being sensitive to load measurements in different directions. Furthermore, it is made from inexpensive, commonly available cantilever beam load cells. In the least accurate direction, Mx, our measurements were consistently 20% below the nominal applied load. In the most accurate directions, Fx, My, and Mz, our measurements were consistently within 5% of the nominal applied loads. Performance can be optimized using the condition number of the transformation matrix. The full-scale version of the hex sensor is also designed and optimized based on its condition number. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 43).

Quantifying the fouling resistance of Accident-Tolerant Fuel (ATF) cladding coatings with force spectroscopy

Sun, 01 Jan 2017 00:00:00 GMT

Quantifying the fouling resistance of Accident-Tolerant Fuel (ATF) cladding coatings with force spectroscopy Auguste, Rasheed CRUD (Chalk River Unidentified Deposits) is buildup of metal oxides on the interior of nuclear reactors. This is caused by corrosion in reactor internals, leading to problems such as coolant contamination in porous deposits left by CRUD. CRUD has forced many nuclear reactors into temporary shutdown or production downgrades, costing millions of dollars US per reactor. If the CRUD growth factors could be fully understood, they could be controlled, and the CRUD problem could be eliminated altogether. Atomic force microscopy can be used to measure the force, or the strength of the CRUD-clad bond with different materials. This research focuses on answering this question: How does the force change between CRUD particles and different materials that could be used for reactor cladding? This study will analyze lab-grown CRUD samples on different substrate materials and characterize CRUD growth on each. It was found the CRUD-bond forces (from least to greatest) on silicon carbide (SiC), Titanium aluminum carbide (Ti2AlC), and max-phase zirconium alloy 211(Zr4M211) behaved similarly in air and in water. The forces on each surface increased with increasing dwell time for the Fe3O4 particle AFM tip; in contrast, most adhesion forces stayed constant with the NiO AFM tip. Furthermore, these CRUD forces were compared to other non-accident tolerant fuels, and there are cases in which non-ATF materials show more CRUD resistance (less adhesive force) than ATF-materials. This study's analysis could be applied to other materials to be used for reactor cladding. Once the material with the lowest-strength CRUD bond is identified and installed, the nuclear industry could save millions of dollars US per reactor fuel cycle. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 418-420).

Assessing the applicability of the ASME V&V20 standard for uncertainty quantification of CFD in nuclear systems fluid modeling

Sun, 01 Jan 2017 00:00:00 GMT

Assessing the applicability of the ASME V&V20 standard for uncertainty quantification of CFD in nuclear systems fluid modeling Alvarez, Andres Felipe, S.B. Massachusetts Institute of Technology Advanced modelIng and sImulatIon (M&S) of nuclear systems could offer a key contrIbutIon In enhancIng the competItIveness and safety performance of nuclear power plants. Large multI-organIzatIonal InItIatIves such as the ConsortIum for Advanced SImulatIon of LIght Water Reactors (CASL) and the Nuclear Energy Advanced ModelIng and SImulatIon (NEAMS) emphasIzes the Importance of M&S research to the U.S. nuclear Industry. UncertaInty QuantIfIcatIon (UQ) represents a fundamental area of research necessary to expand the applIcatIon of M&S Into nuclear Industry, but the fIeld Is stIll not mature, and no general consensus exIsts on current UQ methods. In thIs study, the ASME V&V20 I a proposed methodology for UQ of CFD -- Is applIed to a benchmark nuclear system turbulent mIxIng case In an effort to assess the applIcabIlIty and lImItatIons of the standard. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 73-76).

Construction of a model for the improved planning of MCO-informed VMAT in RayStation using a knowledge base of clinical IMRT-MCO treatment plans

Sun, 01 Jan 2017 00:00:00 GMT

Construction of a model for the improved planning of MCO-informed VMAT in RayStation using a knowledge base of clinical IMRT-MCO treatment plans Colbert, Caroline M Intensity Modulated Radiation Therapy (IMRT) is a type of external beam radiation therapy that has proven effective at treating many cancers. A related therapy type, Volumetric Modulated Arc Therapy (VMAT), has the potential to provide comparable dose coverage to tumor sites while better sparing nearby organs at risk (OARs). Multi-criteria Optimization (MCO) is an algorithm that is used to optimize a patient's personalized IMRT treatment plan. VMAT treatment plans cannot be optimized using early versions of the MCO algorithm. The purpose of this study was to construct a model for the automated generation of VMAT treatment plans for prostate cancers using a knowledge base of previously implemented IMRT-MCO treatment plans. An initial model configuration was iteratively refined to produce VMAT plans that represent a quality 'first pass" that can be further optimized by trained treatment planners. The clinical implementation of a model like this one could significantly improve the timeliness of standard non-MCO VMAT optimization methods. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 51-53).

The economic and political significance of Russia's RBMK reactors

Sun, 01 Jan 2017 00:00:00 GMT

The economic and political significance of Russia's RBMK reactors Corney, Daniel E The safety of continued operations of Russian Raktor Bolshoy Moshchnosti Kanalnyy (RBMK) reactors is often questioned. The original RBMK design was riddled with deficiencies in its shutdown procedures resulting in unsafe operation under certain conditions, most notably resulting in the April 26th Chernobyl disaster. Despite implementing modifications to correct these problems, almost all countries permanently cancelled existing RBMK reactor operations. The sole exception to the European decommissioning effort was Russia. In Russia, RBMKs make up approximately 35% of the country's nuclear power, and are a significant source of heat energy and electricity for specific high priority and remote regions. As a result, Russia relies on the RBMK reactors as an important component within a weakened industrial infrastructure. By analyzing the safety concerns of the RBMK reactors in conjunction with the reactors' economic and political contributions to the country, a conclusion as to whether or not Russia should continue operating the reactors or transition to an alternative technology should be discoverable. Subsequent discussion should address the modern safety and operating issues of RBMKs along with the generic risks of operating nuclear power plants to determine whether the reactors' are capable of operating safely. Furthermore, this research should help consolidate existing, yet scattered data, pertaining to the significance of RBMKs to create a concise evaluation of their continued operation. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 38-40).

Designing an experiment to study absorption vs. dose for feedback enabled radiation therapy

Sun, 01 Jan 2017 00:00:00 GMT

Designing an experiment to study absorption vs. dose for feedback enabled radiation therapy Green, Hadrick Alexis In the field of radiation oncology, while there are simulations and devices that allow users to be relatively confident that radiation to the tumor and sparing of healthy tissue is being maximized, the inability to reliably measure and control the dose during radiation treatment is a major source of uncertainty. This uncertainty is due to issues such as organ movement, a lack of precise and constant knowledge of beam current at the target site, and the inability to correctly register dose during hardware or software failures; all of which result in radiation treatments being measured after the procedure or in a fault susceptible manner during the procedure. The integrating feedback f-center dosimeter (IF2D) is a dosimeter that would address these challenges and enable feedback during radiotherapy procedures, which would give doctors and patients confidence that the correct dose was delivered to the target sites without exceeding allowable doses to healthy tissue. An in-situ irradiator will be designed and later used to quantify the relationship between dose and f-center absorption. This design will help guide the future experiment and further the development of the IF2D. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 43-44).

Investigation of velocity gradient as driving force of flow pulsation in fuel assemblies

Sun, 01 Jan 2017 00:00:00 GMT

Investigation of velocity gradient as driving force of flow pulsation in fuel assemblies Everett, Patrick F The presence of quasi-periodic flow pulsations in fuel assemblies has been observed since the 1960's but is still not fully understood. Current design and licensing practices for nuclear reactor fuel mostly rely on 1-dimensional subchannel simulation tools, which might not accurately predict the increased subchannel mixing caused by flow pulsations. The present work develops a quantitative relationship between subchannel mixing and the inter-subchannel velocity gradient, shown to be the driving force of flow pulsation. A sensitivity study on rod-bundle geometry, based on an experiment by Bardet and Balaras at George Washington University, was conducted with a URANS method in transient simulations using the commercial software Star-CCM+. A linear relationship was observed between crossflow mixing and [delta]vbulk, defined as the difference in bulk velocities of adjacent subchannels. A threshold value of [delta]vbulk was seen close to 0.4 m/s, below which very little crossflow mixing was observed. Using these results, an analytical relationship between inter-subchannel velocity gradient and crossflow mixing could be developed and implemented into subchannel codes for more accurate modeling of flow in a fuel assembly. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 24-26).

North Korea's nuclear weapons : interpreting weapon design progress based on nuclear test data

Sun, 01 Jan 2017 00:00:00 GMT

North Korea's nuclear weapons : interpreting weapon design progress based on nuclear test data Kenausis, Luisa R The proliferation of nuclear weapons is a significant global security issue, and it is important to carefully study the nuclear weapons programs of states that are actively engaging in nuclear proliferation. In this thesis, I interpret the seismic and radionuclide data from North Korea's first two nuclear tests in 2006 and 2009, emphasizing the limitations of that data in reaching deterministic conclusions about the precise devices tested by North Korea. I also review the seismological and radiological literatures surrounding a proposed North Korean nuclear test in May 2010, and summarize the process by which that proposal was investigated and rejected. The most recent North Korean nuclear tests, in 2013 and 2016, are reviewed only briefly. It is found here that the technical data available after the North Korean nuclear tests in 2006 and 2009 provide relatively little information about the designs of the devices that were tested. In the case of the 2009 test, the apparent containment of radioactive material from the test could indicate some improvements in the testing process relative to 2006. The explosive yield of North Korea's nuclear tests has generally increased over time, but this trend in yield does not provide clear information about the advances that have been made in the design of North Korean nuclear warheads. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 55-56).

Using molecular dynamics simulations to quantify the energy stored in irradiation defects in tungsten and aluminum

Sun, 01 Jan 2017 00:00:00 GMT

Using molecular dynamics simulations to quantify the energy stored in irradiation defects in tungsten and aluminum Lowder, Sean Radiation damage in materials can create potentially catastrophic effects by causing failure in critical reactor components. In order to prevent such failures, it is imperative that this damage is understood and quantified. Currently, displacements-per-atom (DPA) is the most common form of expressing the amount of radiation a material has received. With its limitations on accurately expressing how much damage remains in a material post-irradiation, the DPA does not provide enough information about an exposed material to fully understand how it is has been compromised. One suggested replacement for the DPA is the Wigner stored energy, which is a measurement of the energy stored in radiation defects. To prepare for future experimental work, irradiation in tungsten and aluminum was simulated and analyzed for trends in defect energy. With increasing amounts of radiation exposure, it was found that the average energy associated with individual defects remains constant, but that defect clustering and dislocation forming increases. Simulations were then performed to mimic the process of calorimetry heating. These simulations showed how the defects annealed out with heating, and the results will be extrapolated to predict experimental results. If Wigner energy can be successfully measured and characterized, it can become a more universal and reliable way of expressing radiation damage, improving safety throughout the nuclear industry. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 49-52).

Experimental evaluation of polychromatic neutron diffraction

Sun, 01 Jan 2017 00:00:00 GMT

Experimental evaluation of polychromatic neutron diffraction Morrell, Jonathan T Neutron diffraction is a technique that allows scientists to measure the arrangement and motions of atoms in a crystalline lattice by observing neutrons scattering at angles that are characteristic of the interatomic distances of the crystal. This is useful for studying the response of crystals to stress, irradiation, or for observing their phases. This thesis implements and analyzes a technique known as polychromatic neutron powder diffraction, which has the potential to be used by an instrument to make many simultaneous neutron diffraction measurements. In this experiment, powder diffraction patterns were measured with a diffractometer in polychromatic mode, using both angle-dispersive and wavelength-dispersive scans of a silicon powder. The intensity and resolution of the Bragg peaks with the instrument in this configuration were compared to Bragg peaks measured by the same instrument in a monochromatic configuration. The intensity of the polychromatic mode was only comparable to the monochromatic mode with looser collimation, which had the consequence of increasing the widths of the measured peaks. This resulted in a polychromatic signal intensity that was greater than the monochromatic signal intensity, and a Bragg peak that was wider than the monochromatic Bragg peak. The effects of the collimators and the sample to detector distances were quantified in experiment and in ray-tracing simulations. While both the monochromatic and the polychromatic configurations had similar counting rates in this experiment, they were both limited by the high background due to the open-beam geometry. A successful implementation of a polychromatic instrument would require substantial filtering and shielding to overcome this effect. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 57-58).

Material characterization and axial loading response of pouch lithium ion battery cells for crash safety

Sun, 01 Jan 2017 00:00:00 GMT

Material characterization and axial loading response of pouch lithium ion battery cells for crash safety Mason, Amber J Recent research conducted at MIT's Impact and Crashworthiness Laboratory (ICL) has focused on material characterization of lithium ion battery cell components for use in the development of an accurate and practical computational model intended to predict mechanical deformation and related short circuit behavior of Li-ion battery cells and stacks in real world impact scenarios. In an effort to continue to refine and validate this modeling tool, characterization testing was conducted on battery cell pouch material using uniaxial stress and biaxial punch tests. At the full cell level, hemispherical punch indentation validation testing and internal electric short circuit testing was conducted on large, high energy pouch cells. Further investigations at the full cell level examined the buckling response of small pouch cells as a result of in-plane axial compression under varying degrees of confinement. To this end, a custom testing device was designed and constructed to provide controllable cell confinement for axial loading experimentation purposes. All experimentation results will feed into a computational model of the cell extended for use in comprehensive mechanical deformation simulation modeling. Thesis: Nav.E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 75-76).

Network control in a globalized world : how Visa and Swift's founding structures serve their stakeholders on the International stage

Sun, 01 Jan 2017 00:00:00 GMT

Network control in a globalized world : how Visa and Swift's founding structures serve their stakeholders on the International stage Cowan, Thomas C., S.B. Massachusetts Institute of Technology The Visa credit card network and the Society for Worldwide Interbank Financial Telecommunications (Swift) network both provide a backbone for financial interchange across the world. Visa's network connects consumers, merchants, banks, and processors to ease the purchases of millions of consumer-facing products worldwide. Swift's interbank network connects banks, corporates, and other financial institutions to ease the flow of high-value, highly-secure international financial transactions. Both networks grew to become industry incumbents in the second half of the 20th century, connecting nearly every country on earth. However, the globalized networks differ in their organizational structures: Visa utilizes a centralized, U.S. focused, hub-and-spoke model; Swift uses a decentralized, transaction-volume neutral, point-to-point network. Although Visa's centralized network fosters innovation, standardization, and security, its U.S.-centered hub pulls the organization from global neutrality and aligns it with the United States on global issues. Meanwhile, although Swift's decentralized network nurtures technological localization-at the expense of technological standardizationits transaction-based global governing structure promotes a relative international neutrality among global organizations. This contrast between Visa and Swift-both networks that balance local and global, centralized and decentralized, and technical and non-technical tensions across the world-reveals the structural effects of worldwide networks, and how network system design impacts global stakeholders in the societies that they touch. Thesis: S.B., Massachusetts Institute of Technology, Program in Science, Technology and Society, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 51-55).

Load bearing interface design for a pan-tilt mechanism for severe marine environments

Sun, 01 Jan 2017 00:00:00 GMT

Load bearing interface design for a pan-tilt mechanism for severe marine environments Beautyman, Michael John, Jr The Naval Research Laboratory (NRL) requested the design of a two-axis gimbal device for the shipboard support of a sensor payload. Previous design efforts presented a low-mass two-axis (pan and tilt) machine. Vibration and shock testing induced failure in the interface between the payload and the tilt shaft, through which the control cabling connected to the sensors, taking the system out of service and creating a hazard for Sailors. This thesis proposes a tapered, hollowed shaft and flange interface connected by an interference fit that is preloaded and retained by a single hollowed bolt for ease of maintenance at sea. This simplified design is a departure from existing rotary tapered interfaces, such as seen in machine tooling, and focuses on connecting massive payloads to their actuators when subjected to severe loading. This design is uniquely suited to withstand large bending moments and loading as demanded by military standards for shock. A custom rig was designed and constructed to subject reduced-scale designs to military standard environmental testing for shock in the laboratory. These test results were analyzed using moving average filtering to develop confidence intervals to validate the design mathematics. A full-scale prototype was manufactured and subjected to shock testing and analysis. The design exceeded all requirements and is ready for immediate integration into the gimbal. This research also revealed the potential for tapered interfaces to connect massive payloads to their actuators in industry. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 123-125).

Examination of hull forms for an Offshore Nuclear Plant

Sun, 01 Jan 2017 00:00:00 GMT

Examination of hull forms for an Offshore Nuclear Plant Jagoe, Randall Thomas The Nuclear Science and Engineering Department at MIT has a concept design for an Offshore Nuclear Plant (ONP). This project highlights the advantages of the offshore location by reducing the risk of natural disasters and cost of terrestrial nuclear power facilities. The original ONP conceptual design consists of a large cylindrical floating platform similar to existing platforms in the offshore oil and natural gas industries. This study investigates the advantages and disadvantages of different hull forms that the ONP may use in an effort to identify an optimal balance between hull configuration and stability. Multiple platform designs were modeled to compare the differences in seakeeping and stability. These variants explored the characteristics and combinations of fiat hull plating to replace the original cylinder shape, lengthening the platform to minimize overall depth and draft. The different hulls were modeled and then analyzed using a three dimensional radiation-diffraction panel method to simulate each platform's response in a given sea state. The variants were compared utilizing the JONSWAP spectrum for a 100-year storm in North Sea and evaluating the response in six degrees of freedom. While seakeeping performance is the primary characteristic evaluated, other effects of the design changes such as mooring complexity, ease of construction, and arrangeable area were also compared. The key trade off is the seakeeping performance prediction versus the estimated economic benefits of the alternate hull form arrangement. This consideration has to be made with respect to the actual meteorological and ocean conditions for the operational location. This is particularly true with respect to ocean depth, as the deep draft of the vertically arranged hulls can allow for greater non-linear effects on the motions. For the environment specified in this study and the economic benefits perceived by the design, the laterally arranged "stretched" design is worthy of more attention. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 61).

Slip clutch design for position sensitive systems in marine environments

Sun, 01 Jan 2017 00:00:00 GMT

Slip clutch design for position sensitive systems in marine environments Finley, Thomas Patrick The Naval Research Laboratory (NRL) requested a two-axis pan tilt mechanism be designed, built, and tested for shipboard deployment of a sensor payload. Of paramount consideration to this design was the robustness of the system in the face of wave impact loading from "green water" taken over the superstructure of naval vessels. Central to providing such a system is the prevention of drive train failures given wave or other forms of impact loading. Through the course of work completed for his Master's thesis, Nathan M. Mills brought the design effort through initial bench testing. Several failures were experienced due to minor design flaws and mechanical component selection. One component selection that required improvement was the torque limiting slip clutch used in both the pan and tilt drive sections. The unit selected induced positioning errors resulting from backlash inherent to its design. The backlash encountered is unavoidable when using the type of slip clutch selected, as it is with many of the slip clutches available to the machine designer. Slip clutches are available that have limited backlash, but the majority of these are friction based and have setpoints that either do not have tight tolerances or change as the component is cycled. The goal of the present work was to design a slip clutch that maintains its setpoint and minimizes backlash to allow for its shipboard use in the NRL sponsored pan tilt system. The design was completed in a manner that supports the use of the slip clutch in other systems that require accurate positioning and torque overload protection in both marine and non-marine environments. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 133-134).

Intent-aware collision avoidance for autonomous marine vehicles

Sun, 01 Jan 2017 00:00:00 GMT

Intent-aware collision avoidance for autonomous marine vehicles Leavitt, Joseph William Applications of autonomous marine vehicles in dynamic and uncertain environments continuously grow as research unveils new enabling technology and academic, commercial, and government entities pursue new marine autonomy concepts. The safe operation of these vehicles in the marine domain, which is currently dominated by human-operated vehicles, demands compliance with collision avoidance protocol, namely the International Regulations for Preventing Collisions at Sea (COLREGS). Strict application of this protocol can lead to a highly constrained motion planning problem, in which it is difficult for a vehicle to identify a safe and efficient motion plan. This thesis proposes a multi-objective optimization-based method for COLREGS-compliant autonomous surface vehicle collision avoidance in which vehicles use shared intent information, in addition to vehicle state information, to identify safe and efficient collision avoidance maneuvers. The proposed method uses intent information to relax certain COLREGS-specified constraints with the goal of providing sufficient maneuvering flexibility to enable improvements in safety and efficiency over a non-intent-aware system. In order to arrive at an intent-aware solution, this thesis explores the concept of intent, including intent formulations for the marine domain, intent communications, and the application of intent to the COLREGS-compliant motion planning problem. Two types of intent information are specifically evaluated: COLREGS mode intent, in which the give-way vessel in an overtaking or crossing scenario communicates its intent to maneuver in a certain direction with respect the stand-on vessel, and discrete trajectory intent in which vehicles communicate projected future positions. Simulations and on-water experiments demonstrate the feasibility of the proposed intent-aware method, as well as improvements in performance, in terms of both vehicle safety and mission efficiency, over a non-intent-aware, COLREGS-compliant collision avoidance method. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 259-278).

Design, evaluation, and validation of a naval ship structural health monitoring tool

Sun, 01 Jan 2017 00:00:00 GMT

Design, evaluation, and validation of a naval ship structural health monitoring tool Olena, Jessica Jill The US Navy implements structural preventative maintenance procedures onboard its vessels using ship's personnel inspection. These procedures have been largely successful in identifying major problem areas before any interference with mission execution has occurred. However, changes in the Navy's manning philosophy to minimal manning and new ship designs focused on automation encourage a re-evaluation of these structural preventative maintenance procedures. Automation of structural inspection and damage detection would reduce associated manpower costs as well as inform better preventative maintenance schedules for US Navy vessels. This study outlines a modeling tool for structural health monitoring using nonlinear Kalman Filter methodologies such as the Extended Kalman Filter and the Ensemble Kalman Filter to identify damage within a structural model. Through the observation of structural responses and the formulation of a Kalman Filter, it is possible to produce estimates of structural parameters related to damage, specifically changes to elastic modulus and changes in material density. The results of this modeling tool were evaluated to quantify the time and length scales required for damage detection and were validated against a structural model generated in the MAESTRO Global Structural Analysis software suite. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 123-125).

Design and numerical analysis of an unconventional surface-piercing propeller for improved performance at low and high speeds

Sun, 01 Jan 2017 00:00:00 GMT

Design and numerical analysis of an unconventional surface-piercing propeller for improved performance at low and high speeds Parker, Justin Richard Traditional propellers operate fully submerged, with cavitation limited as much as possible in order to minimize its disruptive and damaging consequences. Conversely, supercavitating propellers operate in an encompassing vapor cavity, thereby averting these negative effects while substantially reducing drag on the blades. Surface-piercing propellers, operating under a similar concept as supercavitation, often achieve even greater efficiency by drawing in an air cavity from the free surface. Existing small craft have demonstrated the ability of such propellers to yield extremely high speeds (110+ knots); nevertheless, the full potential of these propellers has yet to be explored. In particular, designs often neglect low-speed performance, focusing solely on high-speed operation. This research therefore developed a new surface-piercing propeller concept designed instead to maximize performance across the spectrum of operating speeds. Applying established theory for supercavitating hydrofoils, the new blades were shaped based on theoretical maximally-efficient two-dimensional profile sections. Furthermore, in order to affect the low-speed performance enhancement, the trailing edge of each profile was appended with a unique "tail" form that allows the blade to resemble a traditional propeller when operating at subcavitating speeds without sacrificing supercavitating performance. The design used an existing racing propeller as a baseline for comparison, matching certain characteristics (rotational speed, advance speed, number of blades, hub size) in order to ensure equivalent operating conditions. Computational fluid dynamics (CFD) of the 2D profiles informed changes to the profile shapes until lift-to-drag (L/D) was maximized while ensuring a fully-encompassing vapor cavity. The complete propeller was drafted from these optimized radial sections for full 3D CFD analysis. Results from both the 2D and 3D CFD simulations revealed promising benefits to propulsive efficiency. High-speed performance met or exceeded that of the baseline propeller, and low-speed performance showed significant improvement. This surface-piercing propeller concept offers an unconventional design with convincing results for balanced low- and high-speed operation. Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 95-98).

Calculation of the axial charge of a heavy nucleon in Lattice QCD

Fri, 01 Jan 2016 00:00:00 GMT

Calculation of the axial charge of a heavy nucleon in Lattice QCD Pefkou, Dimitra Anastasia In this thesis, we aim to calculate the non-renormalized axial charge gA of a heavy nucleon made out of quarks at the physical mass of the strange quark. We present the framework of Lattice QCD which makes the calculation of such observables attainable from first principles. The data used for the estimation of gA were obtained on a 243 x64 hypercubic lattice with lattice spacing a ~ 0.12 fm and pion mass m[pi] = 0.450 GeV. Three different source-sink seperations were used, tsink = [12a, 14a, 16a]. For each timeslice seperation signal we perform a correlated x2 fit and obtain the following values for gA: 0.551, 0.564 and 0.556. The unrenormalized value value for gA is extracted taking the limit as tsink --> [infinity] and is shown to be gA = 0.558. We discuss how the accuracy of this result is compromised by the small number of tsink values, by excited state contamination and by the increase of statistical noise with time. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 55-57).

Study of a short distance top mass with a cross-section at NNLL + NNLO

Sun, 01 Jan 2017 00:00:00 GMT

Study of a short distance top mass with a cross-section at NNLL + NNLO Bachu, Brad We consider top-quarks produced at large energy in e+e- collisions and address the question of what top-mass can be measured from reconstruction. The production process is characterized by the center-of-mass energy, Q, the top mass, m, the top decay width, It, and also AQCD. These scales are well separated and can be disentangled with effective theory methods such as the Heavy-Quark Effective Theory and Soft-Collinear Effective Theory. We compute a top mass observable for future e+e- colliders to next-to-next-to-leading-logarithmic order + [Omicron] [alpha] 2/[sigma](NNLL+NNLO), which goes beyond previous next-to-leading-logarithmic + [Omicron] [alpha] 2/[sigma] (NLL+NLO) analysis. We use the two-loop heavy quark jet-function, [Omicron] [alpha] 2/[sigma] corrections to the partonic hemisphere soft function, and hard matching for boosted tops at two loops. We find that the higher order corrections exhibit good convergence and reduced uncertainty in this cross section. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 49-51).

Spin-orbit coupled Bose-Einstein condensates with observation of a stripe phase

Sun, 01 Jan 2017 00:00:00 GMT

Spin-orbit coupled Bose-Einstein condensates with observation of a stripe phase Burchesky, Sean In this work we build a new spin-orbit coupling experiment to observe the supersolidlike stripe phase. The phase diagram of a 1-dimensional spin-orbit coupled Bose- Einstein condensate shows several interesting phases including the stripe phase. We find the stripe phase particularly interesting because the condensate develops a density modulation in free space while remaining superfluid, which are the signature of supersolidity. In order to observe the stripe phase, we develop a novel spin-j basis which uses the orbital bands of an optical superlattice. Our choice of pseudo-spin basis allows the condensate components to remain miscible at high enough spin-orbit coupling strengths to observe the stripe phase. The superlattice constitutes a chain of spins which develop an antiferromagnetic spin texture and a density modulation at twice the lattice spacing. Breaking the discrete translational symmetry of the lattice while maintaining superfluidity indicates the formation of a lattice supersolid which we detected with Bragg scattering. Finally, the density modulation of the stripe phase is measured with a Bragg reflected beam and a camera setup to resolve the angular spread of the beam. An angle resolved, coherent Bragg beam is direct evidence of the stripe phase density modulation in free space. The formation of a free space density modulation in a superfluid Bose-Einstein condensate breaks the continuous spatial translation symmetry of space; fulfilling the definition of supersolidity. My primary contributions to the work include: controlling the superlattice, designing and building the Bragg detection scheme, some data collection and analysis. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references.

Resolution effects in the hybrid strong/weak coupling model

Sun, 01 Jan 2017 00:00:00 GMT

Resolution effects in the hybrid strong/weak coupling model Hulcher, Zachary R Within the context of a hybrid strong/weak coupling model of jet quenching, we study the consequences of the fact that the plasma produced in a heavy ion collision cannot resolve the substructure of a collimated parton shower within it to arbitrary resolution. We introduce a screening length parameter, LRes, proportional to the inverse of the local temperature in the plasma, estimating the value of the proportionality constant from both weakly coupled QCD calculations and holographic calculations appropriate in strongly coupled plasma. We then modify the hybrid model so that when a parton in a jet shower splits, its two offspring are initially treated as unresolved, and are only treated as two separate partons losing energy independently after they are separated by a distance LRes. This modification delays the quenching of partons with intermediate energy, resulting in the survival of more hadrons in the final state with PT in the several GeV range. We demonstrate that this effect modifies the jet shapes and jet fragmentations functions, as it makes it more probable for particles carrying a small fraction of the jet energy at larger angles from the jet axis to survive their passage through the quark-gluon plasma. We analyze the consequences of different choices for the value of the resolution length LRes on both partonic and hadronic jet shapes and fragmentation functions, as well as on missing-PT observables. More generally, we discuss the qualitative consequences, and importance, of including the effects of finite resolution. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 33-34).

Search for Higgs to invisible decays in vector boson fusion production

Sun, 01 Jan 2017 00:00:00 GMT

Search for Higgs to invisible decays in vector boson fusion production Dominguez, Patricia Zoila A search for invisibly decaying Higgs bosons is performed using the vector boson fusion production (VBF) mode. This search was conducted using Run 2 data, collected by the CMS detector at the LHC in 2016 at a center of mass energy of 13 TeV, corresponding to an integrated luminosity of 5.9 fb-1. The control regions for the signal, invisibly decaying VBF Higgs bosons, are estimated using a cut-based selection strategy adapted from prior analyses. Selection criteria for the signal is applied as well. Assuming standard model Higgs boson cross sections and acceptances, the observed (expected) upper limit on the signal strength of VBF Higgs bosons invisibly decaying at mH = 125 GeV is found to be r < 54.7 (51.8) at a 95% confidence level Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 51-52).

Demonstrating visibly transparent solar cells and photodetectors

Sun, 01 Jan 2017 00:00:00 GMT

Demonstrating visibly transparent solar cells and photodetectors Jungbluth, Anna, S.B. Massachusetts Institute of Technology The fabrication of inorganic semiconductor devices, such as silicon solar cells and photodetectors, is despite significant research still expensive and energy intensive. Especially for solar cells, high upfront costs are a limiting factor for large-scale fabrication and implementation. Organic semiconductors have attracted increasing attention over the last decade for their optoelectronic properties and potential applications in electronics and photonics. The ease of processing, light weight and low cost of organic semiconductors provides the opportunity for inexpensive, large-scale fabrication. In addition, the mechanical flexibility and bandgap tunability of organic materials enables the fabrication of flexible and semi-transparent organic solar cells and photodetectors that could be installed on any surface and integrated into windows and displays. This thesis demonstrates visibly transparent solar cells and photodetectors, fabricated using the organic materials tetraphenyldibenzoperiflanthene (DBP) and chloroaluminum phthalocyanine (CIAlPc). We fabricated our devices through spin-coating, thermal evaporation and sputtering and characterized the performance of our devices by measuring the current-voltage behavior, external quantum efficiency and visible transparency. Our devices demonstrate an average visible transparency of around 56%, power conversion efficiencies between 0.53% and 1.36% and specific detectivities on the order of 1011 to 1012 Jones. These values are comparable to results found in literature. The primary goal of this work is to highlight the potential of organic materials for transparent electronics and to provide a detailed overview of the fabrication and characterization techniques needed to advance research in this area. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 62-66).

Exploration of new methods for Lattice QCD

Sun, 01 Jan 2017 00:00:00 GMT

Exploration of new methods for Lattice QCD Rios Tascon, Andres We explore two methods aimed at alleviating two difficulties in Lattice QCD: statistical noise and data storage. The first method intends to improve the signal-to-noise (S/N) ratio in three-point correlators, by extending previous work by Detmold and Endres. We test the method in the measurement of two observables: the nucleonic axial charge, and a matrix element computation related to the electromagnetic form factor of the rho meson. Only in the case of the rho we see a very slight improvement. We conclude that, in general, a case-by-case study would be needed to determine the effectiveness of the S/N optimization. The second method that we study aims to improve data compression of gauge fields. It consists in generating a set of matrices distributed roughly uniformly along the group manifold, and constructing fine lattices around each of these matrices. We show that this compression can indeed provide better performance for SU(2) and SU(3) than the Lie algebra compression, but the improvement is not very significant. Nevertheless, we show that it is fairly close to the best compression one could hope to achieve with this type of method. We find that the compression procedure is very costly, which makes it currently impractical for machine precision- compression. We conclude that studies must be done to determine if it can be improved by using additional information from the gauge fields. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 59-60).

Formalism for the rapid evolution of primordial black holes

Sun, 01 Jan 2017 00:00:00 GMT

Formalism for the rapid evolution of primordial black holes Russell, Megan, S.B. Massachusetts Institute of Technology This thesis presents two different formalisms which can be used together to evolve a density perturbation produced during inflation forwards in time in the radiation-dominated era of the early universe. The first formalism, based on early work by Misner and Sharp, is for the evolution of a perfect fluid in spherical symmetry under its own gravity. This allows us to efficiently determine if a black hole will form, but due to the formation of a singularity, it does not allow us to extract the black hole's mass. The second, new, formalism allows us to evolve the density perturbation past the formation of a singularity until a time where we can reasonably extract the mass of the black hole. This new formalism has been designed to do this computation as rapidly as possible, improving over our previous methods. The limits of this new formalism are investigated, details regarding a numerical implementation of our code are discussed, and a proof of concept example is presented. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 47-48).

Jet substructure at the Large Hadron Collider

Sun, 01 Jan 2017 00:00:00 GMT

Jet substructure at the Large Hadron Collider Tripathee, Aashish In this thesis, we use the CMS Open Data to study the 2-prong substructure of jets. We use CMS's particle flow reconstruction algorithm to obtain jet constituents, which we then use to perform various jet substructure studies. After validating our basic kinematics and substructure results through a comparison to results from parton shower generators, we extract the 2-prong substructure of the leading jet using the soft drop algorithm. We find good agreement between the results from the Open Data and those obtained from parton shower generators. For the 2-prong substructure, we also compare to analytic calculations performed to modified leading-logarithmic accuracy. To our best knowledge, this is the first ever physics analysis based on the CMS Open Data. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 57-60).

Lower bounds on the classical simulation of quantum circuits for quantum supremacy

Sun, 01 Jan 2017 00:00:00 GMT

Lower bounds on the classical simulation of quantum circuits for quantum supremacy Dalzell, Alexander M Despite continued experimental progress, no task has yet been performed on quantum technology that could not also have been performed quickly on today's classical computers. One proposed path toward achieving this milestone, which is often referred to as quantum supremacy, is to perform specific types of quantum circuits for which it is guaranteed, under plausible complexity theoretic conjectures, that any classical approximate weak simulation algorithm for these circuits must take more than polynomial time. Instantaneous quantum (IQP) circuits and Quantum Approximate Optimization Algorithm (QAOA) circuits are examples of circuits with this guarantee under the assumption that the polynomial hierarchy (PH) does not collapse. However, these arguments do not communicate how large these quantum circuits must be built before simulating them is hard in practice. We show how a fine-grained version of this assumption involving the PH leads to a fine-grained lower bound on the simulation time for IQP and QAOA circuits. Using the lower bound, we conclude that IQP circuits must contain roughly 1700 qubits, and QAOA circuits must contain roughly 7100 qubits before their simulation would be guaranteed to be intractable on today's fastest supercomputers. Additionally, we apply the same logic to find an asymptotic lower bound on the classical weak simulation of Clifford + T circuits with n qubits, m Clifford gates, and t T gates, concluding that any simulation with runtime of the form poly(n;m)2[gamma]t must have [gamma] > 1/135 [approximately equal] 0:0074. The best existing algorithm of this form [gamma] [approximately equal] 0:228. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2017.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 91-93).

Robotic grasping of Orbital Replacement Units

Sun, 01 Jan 1989 00:00:00 GMT

Robotic grasping of Orbital Replacement Units Greiner, Helen Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1989.; Includes bibliographical references (leaves 55-56).

A digital radio modem for the Mobile Robot Project

Tue, 01 Jan 1985 00:00:00 GMT

A digital radio modem for the Mobile Robot Project Pietrzak, Carl Martin Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1985.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING

TCAQ-based polymer for electrochemically mediated separations

Sun, 01 Jan 2017 00:00:00 GMT

TCAQ-based polymer for electrochemically mediated separations Thai, Emily (Emily Sue) Redox-mediated separation systems offer the potential to efficiently desalinate water and to purify contaminated waste streams, among other health and environmental applications. A TCAQ-based polymer, unique for its two-electron redox reaction, was synthesized for use in redox-mediated separation systems, and its performance was quantified in low-concentration aqueous salt solutions. The polyvinyl ferrocene (PVF)//PTCAQ system displayed an ion adsorption capacity much higher than previously reported literature values for capacitive or redox deionization systems. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 35-36).

Assessing the criticality of germanium as a by-product

Sun, 01 Jan 2017 00:00:00 GMT

Assessing the criticality of germanium as a by-product Tadjfar, Nagisa Although germanium production is currently nowhere near its supply potential, many sources cite germanium, a by-product material produced primarily from zinc and coal, as a critical metal. Current methods for assessing criticality include frameworks that rely on geopolitical risk metrics, geological reserves, substitutability, and processing limitations during extraction among others but there is a gap in understanding the complex supply and demand dynamics that are involved in the market for by-products. This thesis addressed this gap by assessing the supply risk of germanium using an econometric framework to generate estimates of price elasticities. Annual world production and price data of years 1967 - 2014 for germanium was used to construct supply and demand models in order to obtain estimates for the price elasticities of supply and demand. Ordinary least squares (OLS) regression was used on an autoregressive distributed lag (ARDL) model for both supply and demand. The supply model was constructed with price, zinc production, and 5-year interest rate as shifters along with lag terms for germanium production, germanium price, 5-year interest rate, and zinc production. The adjusted R2 was 0.761 and the long term supply price elasticity was found to be 0.05 with an upper bound of 0.7 and a lower bound of -0.6 indicating that germanium supply is price inelastic. In a similar fashion, a demand model was constructed with two structural breaks accounting for fundamental changes in the market structure in 1991 and 2003, along with lag terms for germanium production, germanium price and antimony price. The adjusted R2 value for the demand model was 0.683 and the price elasticity was 0.05 with an upper bound of 1 and a lower bound of -1 indicating that demand, too, is price inelastic. This creates an added risk for supply shortages, adding to the criticality of germanium. However, the stabilizing behavior of its carriers, coal and zinc, reduce the likelihood of an actual shortage. This type of analysis improves upon existing methods and can lead to more accurate quantified estimates for long-term criticality. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 37-38).

Selective solar absorber materials : nanostructured surfaces via scalable synthesis

Sun, 01 Jan 2017 00:00:00 GMT

Selective solar absorber materials : nanostructured surfaces via scalable synthesis Rubin, Julia G. (Julia Grace) Current solar to thermal energy conversion technologies, including concentrated solar power (CSP) and solar water heaters (SWH) utilize absorber surfaces that collect incident solar radiation. However, these absorber surfaces emit thermal energy (at their temperature) in the infrared (IR) spectrum, resulting in decreased overall efficiency for solar-to-thermal conversion. Selective absorber surfaces are highly absorptive in the solar spectrum, yet highly reflective in the infrared spectrum and therefore have the potential to minimize thermal energy loss. Copper Oxide (CuO) nanostructures are a candidate selective absorber material due to high absorptivity in the solar spectrum (about 95%), relatively high reflectance in the IR spectrum, scalability, and ease of fabrication. The aim of this study was to analyze optical properties and thermal stability of CuO surfaces in order to assess its feasibility as a selective absorber material. CuO nanostructures were synthesized on copper via chemical wet processing. Samples were thermally cycled to simulate day/night cycles in a typical SWH application. A cycle consisted of 12 hours of heating at 200°C and 12 hours of cooling to ambient temperature. Samples were cycled 1, 2, 3, 8, and 10 times. Surface optical properties were characterized using Ultraviolet-Visible Spectroscopy (UV-Vis) and Fourier Transform Infrared Spectroscopy (FTIR) and compared to optical properties of Pyromark®, the industry standard. Reflectance in the IR spectrum of CuO samples was found to increase after initial heating, whereas the absorptivity decreased. This tradeoff in optical performance resulted in an overall efficiency that remained relatively stable between 0 and 10 cycles (69.5±1.6%, 70.2±1.6%, respectively). CuO samples were found to be roughly 10% more efficient (optical conversion) than Pyromark® (npyromark,3x = 59.5±0.7%), indicating that CuO samples have the potential to be an efficient selective absorber material. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 32).

Synthesis and characterization of magnetic nanorings for neuronal stimulation

Sun, 01 Jan 2017 00:00:00 GMT

Synthesis and characterization of magnetic nanorings for neuronal stimulation Garcia, Francisco J.(Materials scientist) Massachusetts Institute of Technology Magnetic nanorings (MNRs) are anisotropic nanomaterials that can support a magnetic vortex state, which can yield both colloidal stability and large hysteretic power losses when exposed to an alternating magnetic field (AMF). Coupled with the biocompatibility of polymer surface coatings, MNRs have the potential of being used for many biological applications, including neuronal stimulation, drug delivery, and cancer hyperthermia. In this work, we synthesized varying geometries of MNRs via a thermal decomposition route and characterize their structural, chemical, and magnetothermal properties. Scanning and transmission electron microscopy was used to analyze surface morphology and geometry of nanostructures. X-ray diffraction allowed for differentiation of paramagnetic and ferrimagentic phases of synthesized iron oxide. Vibrating scanning magnetometry and induced coupled plasma atomic emission spectroscopy were used to determine magnetic properties, including saturation magnetization (Ms) and coercive field (He). Finally, calorimetric measurements were performed to calculate specific power losses (SLPs) of varying compositions of MNRs. We demonstrate that MNRs exhibit hysteretic power loss and can be optimized for neuronal stimulation under biologically safe AMF conditions. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 32-33).

Hydrophobic nanostructured glass surfaces using metal dewetting process

Sun, 01 Jan 2017 00:00:00 GMT

Hydrophobic nanostructured glass surfaces using metal dewetting process Chao, Michelle (Michelle L.) This project aims to create a hydrophobic surface through a top down fabrication process of a nanostructure surface on a glass surface. The nanostructure is created through reactive ion etching utilizing silver as a mask. The silver mask is the result of a solid state thermal dewetting process which is controlled by varying the temperature and time of the process. Using this fabrication process, contact angles up to 137 degrees was achieved. Further surface modification resulted in contact angles exceeding 150 degrees. Superhydrophobic surfaces were made with the addition of a secondary roughness feature and the a PDMS coating. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 18).

Optimizing the synthesis process of wood-derived biomorphic silicon carbide

Sun, 01 Jan 2017 00:00:00 GMT

Optimizing the synthesis process of wood-derived biomorphic silicon carbide Alsalloum, Abdullah Yousef Biomorphic silicon carbide, a porous, light and high strength ceramic typically derived from natural wood, has great potential in high temperature and structural applications. Over the past several years, researchers have developed three main routes to fabricating biomorphic SiC: reactive infiltration of molten Si, chemical vapor infiltration of Si or SiO, and SiO₂-bearing solution infiltration. In this study, the latter was investigated and optimized. In addition, a novel synthesis technique, Si suspension infiltration, is proposed that overcomes the major issues present in the current methods. Four wood species (balsa, pine, maple and oak) offering a wide range of porosities were infiltrated with colloidal SiO₂ under varying pressure conditions, and the corresponding weight gains were recorded and studied. The samples were then fired at 1600 °C for 2h under argon flow, and examined via X-ray diffraction (XRD), scanning electron microscopy (SEM) and compression testing. It was found that applying pressure or vacuum produced more effective SiO₂ weight gains. Pine showed superior absorption to other types with its maximum obtained value achieved under vacuum followed by pressure. The starting concentration of SiO₂ solution proved to be crucial in controlling the final mechanical properties of the specimens. XRD analysis revealed that the resulting samples consisted of nearly pure SiC, and SEM images indicated that the initial structure of wood was retained. Due to the nature of the reactions involved with using SiO₂ as a-precursor, the produced specimens tend to be mechanically weak. The new synthesis approach involves the use of <10 pm sized particles of Si instead of nano-sized SiO₂ particles. Pine was selected to serve as the template for absorption, and after two infiltration treatments, the sample absorbed 55.6% of its weight, ~4% higher than its theoretical stoichiometric need, 51.3%. EDS analysis revealed that Si was able to spread homogenously, and XRD spectra confirmed the material identity to be composed of mainly pure SiC with minor trace metal contamination. Compression testing illustrated better mechanical properties of the Si prepared specimen, suggesting the potential of this method to replace existing techniques. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 41-46).

Sulfate attack on cement paste with volcanic ash : durability analysis

Sun, 01 Jan 2017 00:00:00 GMT

Sulfate attack on cement paste with volcanic ash : durability analysis Johnston, Maranda Lee Sulfate attack is responsible for deterioration of infrastructure and often occurs in sulfate rich soil or brackish environment. The aim of this study is to investigate the effect of volcanic ash cements when exposed to different forms of sulfate attack, specifically to sodium and magnesium sulfates. Pozzolanic volcanic ash can be a viable partial substitute for Portland Cements to develop cement paste compositions for superior sulfate resistance with potential for durability and sustainable solutions. Pumiceous volcanic ash was used in preparing Roman hydraulic pozzolan concrete that was used to build the Bay of Naples. This study reports the microstructural and mechanical characterization of cement paste with volcanic ash when exposed to accelerated sulfate attack via electrokinetics. The test specimens were exposed to sodium and magnesium sulfate solutions for a period of 30 days. The effect of gradual decomposition of calcium-silicate-hydrate (C-S-H) gel was examined using Raman spectroscopy and Magic Angle Nuclear Magnetic Resonance (MAS NMR), while the mechanical properties were determined using nanoindentation and compression tests. Exposure to magnesium sulfate solution led to formation of magnesium-silicate-hydrate (M-S-H) along with crystallization of gypsum and brucite, while exposure to sodium sulfates led to the formation of thenardite and mirabilite. An optimum mix combination of 10-30% partial substitution of volcanic ash was determined for optimal sulfate resistance and compressive strength. This mix combination was determined by considering the resulting mechanical, micro and pore structure characteristics of the hardened cement pastes. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 31-32).

Sensitivity, selectivity, and stability of a palladium-loaded single-walled carbon nanotube methane gas sensor

Sun, 01 Jan 2017 00:00:00 GMT

Sensitivity, selectivity, and stability of a palladium-loaded single-walled carbon nanotube methane gas sensor McGee, Melissa Keiko There exists a need to detect methane (CH₄) gas, and optical sensors provide many advantages over electronic sensors. Single-walled carbon nanotubes (SWNT) can be used as optical sensors, as SWNTs emit fluorescence upon photoexcitation. The photoluminescent (PL) intensity upon excitation depends on the electronic structure of the SWNT. Here, SWNTs are loaded with palladium (Pd) nanoparticles using sodium dodecyl sulfate (SDS). The Pd-loaded SWNTs offer a detection mechanism for methane (CH 4) by comparing the PL intensity before and after exposure to CH₄.A significant PL change (relative to the experiment) indicates a "turn-on" response to CH₄ Preliminary experiments showed no response to CH4 at zero and high (>10mM) Pd loading in both aqueous solution and film, indicating that there must be an optimal Pd concentration in the middle. This optimal loading for methane response was found to be in the range 2.61mM - 5.21mM Pd²+. The Pd-SWNTs in aqueous solution showed selectivity to CH₄ over nitrogen gas (N₂ and ambient air (20-22% O₂). SDS-SWNT (the control) showed a significant response to N₂ and air while Pd-SWNTs in aqueous solution showed the greatest response to methane. In film, the optimal Pd-loading (5.21mM) for sensitivity was found to exhibit an inexplicable high response to N₂ but still displayed selectivity to methane over ambient air. Pd-SWNTs in aqueous solution and film showed stability of response over time. Pd- SWNTs in aqueous solution maintained the PL intensity with a minor decrease (3- 19% decrease) in Day 14 as compared to Day 1. Pd-SWNT in aqueous solution showed turn-on response under the methane gas in Day 14. In film, the optimal Pd-loading (5.21mM) and a lower Pd-loaded SWNT (2.61mM) displayed a turn-on response to methane after 14 days, showing stability in response over time. This work has thus demonstrated an optimally Pd-loaded SWNT that is sensitive, selective, and stable over time to methane gas. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 48-49).

Electrochemical and structural properties of superionic conductors in aqueous electrolyte

Sun, 01 Jan 2017 00:00:00 GMT

Electrochemical and structural properties of superionic conductors in aqueous electrolyte Jing, Linda Wei The intermittent nature of renewable electricity generation has created a global need for low-cost, highly scalable energy storage. One potential solution is the low-cost air-breathing aqueous sulfur redox flow battery proposed by the Chiang group. Currently, the battery power output is significantly limited by high resistance from the membrane, a superionic conductor. This thesis investigates the electrochemical and structural properties of these superionic conductors (NaSICON and LiSICON) in aqueous electrolyte of varying pH to determine its suitability for this new battery chemistry. The membranes were characterized in acidic, neutral, and alkaline electrolytes through Electrochemical Impedance Spectroscopy (EIS), X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). NaSICON and LiSICON were stable in alkaline and neutral electrolytes, but unstable in acidic electrolytes. The major contribution to membrane instability in acidic electrolyte stemmed from its high interfacial area specific resistance (ASR) of 1.1 x 10³ and 9.5 x 10³ [omega]-cm² for NaSICON and LiSICON, which were 2 magnitudes above the bulk membrane ASR values of 68.6 and 101.0 [omega]-cm² all at 25°C. The high interfacial ASR were due to the incorporation of hydronium ions into the lattice structure and significant surface degradation. Twenty-four hours of exposure in acidic electrolyte resulted in micron-scaled cracks, and only a sparse network was observed after 170 hours. Based on these findings, the theoretical peak powers of the proposed flow battery are 17.1mW/cm² and 4.03mW/cm² for using NaSICON and LiSICON, respectively. For a battery with an alkaline electrolyte, NaSICON is the optimal choice. However, with an acidic electrolyte, further surface remediation methods must be explored. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 49-50).

Assessing materials quality for high efficiency electricity generation

Sun, 01 Jan 2017 00:00:00 GMT

Assessing materials quality for high efficiency electricity generation Postelnicu, Eveline Thermalization losses drastically reduce the efficiency of silicon solar cells. In an age where we need sustainable energy production more than ever, silicon is the best material to target due to its high stake in the sustainable energy market. An organic-inorganic solar cell hybrid of tetracene-covered silicon can reduce thermalization losses through the downconversion process of using a high energy photon to generate two lower energy electron-hole pairs. This occurs through the singlet-triplet fission process that excitons can undertake in tetracene. The effect of the interface quality between tetracene and silicon on successful triplet energy transfer is investigated. RFPCD (Radio Frequency Photoconductive Decay) is used to measure the bulk lifetime as well as the surface recombination lifetime of minority carriers in both n- and p-type Silicon of various doping concentrations. The surface recombination velocity was calculated from the measurement of surface recombination lifetime and analyzed after the silicon underwent RCA clean, RCA clean followed by an HF dip, tungsten nitride ALD, and tetracene evaporation using various combinations of these steps to form appropriate process flows. It was found that the highest surface quality was obtained by the lowest doped wafers. Additionally, similar doping levels were affected similarly by the various processing steps outlined above while the type of dopant did not seem to dictate the surface quality response. Triplet energy transfer was not fully confirmed from tetracene to silicon, but the surface quality turned out to be a very important indication for whether or not this energy transfer could occur. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 54-55).

Designing in virtual reality : tools with the human field of vision

Sun, 01 Jan 2017 00:00:00 GMT

Designing in virtual reality : tools with the human field of vision Chang, Joie Z. (Joie Zhi Fan) Virtual reality, or VR, will be the next common medium for digital visualization. The purpose of this thesis is to explore how designers will use and discover new design methods with the representation in virtual reality. How do computational design tools such as CAD and VR, which are digital representations of the physical, affect our designs of physical space? In this thesis, I explore the benefits and shortcomings of VR as a design medium. My first hypothesis claims that VR will excel in representing site context, depth, and scale, in comparison to CAD. The second hypothesis says that VR will encourage a preference for monumentality and open spaces in comparison to a higher packing density of objects in CAD. The third hypothesis claims that designers will prefer 3d models with realistic rendering textures in VR, more so than CAD. The fourth and final hypothesis is that architects, familiar with CAD, can design immersive views just from a 3d omniscient plan without immersion, unlike novices. The first part of the research is the creation of a proof-of-concept virtual reality design review tool that can be integrated easily into existing design practices. The VR tool allows a user to explore their 3d modeled spaces with full locomotion and visually records their experiences in the space. This VR tool integrates virtual reality into the process of iterative design. Through subject testing, we explore our understanding of how our spatial perception interacts with simulated virtual space and thus affects our manners of designing. The results led us to several different conclusions. First, intuitive perception of scale and other spatial relationships is easier in VR. Secondly, VR, despite its intimate relation to the human scale, does not promote a preference for large spaces and monumentality. Thirdly, designers slightly prefer realistic rendering textures in VR. Finally, those with architecture training perform slightly better than novices in visualizing 3d immersive views from plans. This project illustrates where virtual reality's value and flaws as a digital visualization medium. It examines what manner the mode of representation affects and limits the process of designing and making. Thesis: S.B., Massachusetts Institute of Technology, Department of Architecture, 2017.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (page 35).

Investigating coordinate network based films through mechanical and optical properties

Sun, 01 Jan 2017 00:00:00 GMT

Investigating coordinate network based films through mechanical and optical properties Gallivan, Rebecca Anne Both biological and synthetic materials crosslinked via metal coordinate dynamic chemistry display interesting advanced behavior. In particular, coordinate networks have been shown to form self-healing, self-assembling, and stimuli-responsive behaviors through its tunable optical and mechanical properties as well as its ability to for dynamic networks. However, while the majority of research has focused on characterization of bulk coordinate networks, coordinate complexes have also been shown to be useful in molecular film formation [1 and 2]. This study investigates the mechanical and optical properties of tannic acid and 4 arm catechol polyethylene glycol based coordinate network films. It shows that these films can contribute to energy dissipation and undergo pH-induced optical shifts when used as coatings on soft hydrogels. It also provides evidence that the molecular architecture of the network formers may have considerable effect on the properties and behavior of coordinate network films. Ultimately this work lays the foundation for further investigation of the underlying mechanisms and engineering potential of coordinate network based films. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (page 31).

A brewery and beer garden

Sun, 01 Jan 1933 00:00:00 GMT

A brewery and beer garden Bunshaft, Gordon, 1909-1990 Thesis (B.Arch)--Massachusetts Institute of Technology, Dept. of Architecture, 1933.; MIT copy bound with: A graduate dormitory group for Tufts College / Draveaux Bender. Accompanying drawings held by MIT Museum.; Includes bibliographical references (leaf [41]).

Advanced electrochemical characterization of copper deposition

Fri, 01 Jan 2016 00:00:00 GMT

Advanced electrochemical characterization of copper deposition Wagner, Mary Elizabeth, S.B. Massachusetts Institute of Technology The electrodeposition of copper metal in a concentrated sulfuric acid solution is reported to occur through a four-step mechanism: (I) the dehydration of Cu2+ (H2O)6, (II) the reduction of Cu2+ to cu+, (III) the dehydration cu+ (H2O)6-x, (IV) the reduction of Cu+ to copper metal. The dehydration steps have been found to be responsible for the pH-dependence of the electrodeposition reaction. It is also reported, although not well understood, that the presence of Fe2+ ions affects the reaction kinetics. In this work, the kinetics of copper electrodeposition were studied using alternating current cyclic voltammetry. The reaction was studied at a copper rotating disk electrode with varying concentrations of Cu2+ and Fe2+ . At sufficiently low pH, and a sufficiently high concentration of Fe2+ , the deposition kinetics may be slowed enough to separately observe the two electron transfer steps involved in copper reduction. It was found that Fe2+ ions affect the electrodeposition kinetic by slowing down reaction kinetics, particularly the second electron transfer reaction. Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, February 2016.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 51-52).

Fabrication of reinforced alginate fibers for cell based therapies

Fri, 01 Jan 2016 00:00:00 GMT

Fabrication of reinforced alginate fibers for cell based therapies Carter, Sydney C. (Sydney Cheyenne) Type I Diabetes is a condition in which the pancreas does not produce enough insulin, leading to dysregulation in glucose metabolism. Most Type I diabetics take insulin injections after each meal in order to remain euglycemic. Transplantations of islet cells in immuno-protective alginate capsules has been shown to be promising as a long-term cure for Type I Diabetes. In this study, reinforced alginate fibers were fabricated as an alternative to alginate capsules for islet transplantation. Surgical thread was covered in alginate-cell solution by the microfluidic nozzle system to give a stronger structure to be used for implanting the cells. The thickness of the cell-encapsulated alginate layer produced by microfluidic nozzle processing system was controlled by varying the flow rate of alginate being pumped through the nozzle as well as by varying the speed by which the thread was extracted from the nozzle. The study showed that higher flow rates of alginate and lower thread speeds result in thicker alginate layers for encapsulating more cells within the fiber. The cells remained viable over a month, suggesting plausibility of cell-encapsulated microfibers as a long term solution to diabetes treatment. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, June 2016.; "February 2016." Cataloged from PDF version of thesis.; Includes bibliographical references (page 19).

The utilization of spent black ash from the soda recovery system of the Penobscot Chemical Fibre Company

Sun, 01 Jan 1922 00:00:00 GMT

The utilization of spent black ash from the soda recovery system of the Penobscot Chemical Fibre Company Koch, Fred Chase Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1922.; Includes bibliographical references (leaf 24).

An investigation of reciprocity in the exponential assembly

Thu, 01 Jan 1959 00:00:00 GMT

An investigation of reciprocity in the exponential assembly Pearson, John F; Sims, Robert B Thesis (Nav.E.)--Massachusetts Institute of Technology, Dept. of Naval Architecture and Marine Engineering, 1959.; Includes bibliographical references (leaves 76-79).

Motion tracking with computer vision

Fri, 01 Jan 2016 00:00:00 GMT

Motion tracking with computer vision Clayton, Tyler (Tyler T.) In the Mechatronics laboratory, work is being done to develop methods for robot collision avoidance. A vital component of the project is motion detection and tracking. Currently, 3d-imaging software and hardware are employed, but this technique carries the drawbacks of blind spots in the environment. Since the camera is placed directly above the robot, there are blind spots underneath the robot, which are a major problem. The idea is for the robot to work side-by-side to a human counterpart, which would allow for quicker assembly of parts. But, with the current visual system, the robot would be unable to detect limbs that may maneuver underneath its linkages. This is an obvious problem. In this thesis, an automated rotary vision system attachable to each linkage of the robot is being proposed. By attaching cameras directly to the robot, we will have the increased ability to eliminate blind spots and detect objects in the environment. The proposed assembly involves a four-piece clamp-on shaft collar. Two parts will clamp to the linkages while the other two clamp around enabling free rotation. In testing, this proposed solution was able to track and detect, but it has drawbacks of increased weight to linkages and speed of image processing. Suggestions for improving upon the device are outlined. Overall, this device shows much promise for the Optical Assembly Station. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 27).

Setting language parameters using genetic algorithms

Wed, 01 Jan 1992 00:00:00 GMT

Setting language parameters using genetic algorithms Bourne, Juliet C. (Juliet Cassandra) Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1992.; Includes bibliographical references (leaf 59).

A circular pipelined bus architecture for high-speed computation

Sun, 01 Jan 1984 00:00:00 GMT

A circular pipelined bus architecture for high-speed computation Antaki, Patrick R Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1984.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.; Bibliography: leaves 60-61.

A study of the conditions required for a stable interface between phases in two phase flow

Tue, 01 Jan 1957 00:00:00 GMT

A study of the conditions required for a stable interface between phases in two phase flow Strawson, David George Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1957.; MIT copy bound with: The inlet conditions with aeration tube in dense phase fluidized solids down-flow / by Barnard Stewart Silver [1957]; Includes bibliographical references (leaf 46).

A taxonomy of participatory design projects in architecture

Sun, 01 Jan 2017 00:00:00 GMT

A taxonomy of participatory design projects in architecture Bogoev, Lia Since its advent in the 1960s, participatory design has been an interesting and innovative technique to use in architectural projects. The nature of participatory design projects is varied and diverse. Much of the existing documentation does not provide a generalized framework under which to analyze how participatory design techniques are applied. As a result, it is difficult to understand the benefits or drawbacks to using participatory design. It can also be difficult to evaluate in which context a participatory design technique is appropriate, and how to integrate it within a project. This thesis summarizes eight case studies that use a variety of participatory design approaches within several different contexts and generalizes the approaches for application to other projects. Three methods of categorization have been developed, each providing a different set of considerations for future projects. Thesis: S.B., Massachusetts Institute of Technology, Department of Architecture, 2017.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 55-56).

A study of tidal power project at Passamaquoddy Bay

Fri, 01 Jan 1926 00:00:00 GMT

A study of tidal power project at Passamaquoddy Bay Ko, Choong Myung Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of General Science, 1926.

Electrical analytical balance

Sat, 01 Jan 1949 00:00:00 GMT

Electrical analytical balance Teager, Arthur R Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mechanical Engineering, 1949.; MIT copy bound with: Design of an axial piston air compressor / W. B. Richards. 1949.; Bibliography: leaf 45.

Of frames, scripts, and stories

Mon, 01 Jan 1990 00:00:00 GMT

Of frames, scripts, and stories Seow, Choong Huei Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1990.; Includes bibliographical references (leaves 37-38).

A statistical analysis of ambient noise monitored in the Arctic Ocean Basin

Sat, 01 Jan 1983 00:00:00 GMT

A statistical analysis of ambient noise monitored in the Arctic Ocean Basin Makris, Nicholas Constantine Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1983.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.; Includes bibliographical references.

Arctic Ocean ambient noise.

Mon, 01 Jan 1979 00:00:00 GMT

Arctic Ocean ambient noise. Shepard, George Woods Thesis (Ocean E)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1979.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.; Bibliography: leaves 178-180.

An experimental comparison of hitting mechanics in softball

Fri, 01 Jan 2016 00:00:00 GMT

An experimental comparison of hitting mechanics in softball Jensen, Tori (Victoria M.) To score points to win games, a softball team must be able to hit the ball with as the largest velocity as possible. In softball, there are two well-known hitting models, rotational and linear, yet little quantitative research has been done to determine which model produces the greatest ball velocity and if certain key inputs, such as weight shift and bat velocity, of the models contribute to that velocity. To determine these components, a high-speed EXLIM camera recorded the change in ball position to calculate the its exit velocity, a 70g accelerometer measured centripetal acceleration of the bat to determine bat velocity, while two force plates measured the transfer of weight as nine softball players swung a bat twenty times- ten times with a ball on the tee and ten times with a ball off of the tee. Although it was found that the two hitting models had statistically different weight shifts with 95% confidence, the average ball velocity for a linear model, 22.0 m/s ±1.9 m/s, was not different from the average ball velocity for a rotational model, 22.0 m/s ± 0.7 m/s, at 95% confidence. Since these values are not different with statistical significance, this research concludes that players that weight shift does not effect ball velocity and that players are encouraged to use whichever model feels most comfortable to them. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Page 37 blank. Cataloged from PDF version of thesis.; Includes bibliographical references (page 36).

Two-phase flow of fluids through a horizontal pipe

Tue, 01 Jan 1935 00:00:00 GMT

Two-phase flow of fluids through a horizontal pipe Kelakos, Michael G; Crowley, Arthur H Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1935.; MIT copy bound with: The hydroxylation of chlorinated rubber / Faustino Andreoli and Alfred McDonald.; Appendix contains numerous pamphlets.; Includes bibliographical references.

Finding the swing voter : definitions and survey methods for voter classification

Fri, 01 Jan 2016 00:00:00 GMT

Finding the swing voter : definitions and survey methods for voter classification Swasey, Charlotte (Charlotte A.) This thesis proposes a theory mapping emotional reactions to political information onto a theory of vote decisionmaking and then further onto measurable survey response. Using on-line processing based in emotion, voters form affective summaries about candidates, which store previous information as an emotional response. The act of voting is treated as a single realization of a probabilistic event, with the relative probabilities of each vote option being an expression of the affective summary. These summaries are expressed as warmness or feeling towards each candidate, which can be captured using the ANES Feeling Thermometer scales. A metric of the difference between the scores given to the Republican and Democratic candidates is used, based in the work of William Mayer. This metric suffers from significant survey error, but is related to party ID and expressed vote choice, as well as demographic factors and perceived efficacy. Feeling thermometer responses are found to carry meaningful information about a respondent's relationship to the election and candidate preference. Thesis: S.M., Massachusetts Institute of Technology, Department of Political Science, 2016.; Thesis: S.B., Massachusetts Institute of Technology, Department of Political Science, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 43-48).

Ancient West Mexican bellmaking

Thu, 01 Jan 1998 00:00:00 GMT

Ancient West Mexican bellmaking Doherty, Shawn Patrick, 1976- Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1998.; Includes bibliographical references (leaf 40).

A study of the aerodynamic damping of airfoils in pitching oscillations

Mon, 01 Jan 1940 00:00:00 GMT

A study of the aerodynamic damping of airfoils in pitching oscillations Lindblom, Charles Wm; Brewer, Walter Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1940.; Microfiche copy available in Barker. MIT copy bound with: Characteristics of gasoline-alcohol blends / Edgardo N. Accinelli. 1940.; Includes bibliographical references (leaf 17).

Design of an emergency power plant for the fallout shelter areas of the M.I.T. community

Wed, 01 Jan 1964 00:00:00 GMT

Design of an emergency power plant for the fallout shelter areas of the M.I.T. community Anderson, David M Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1964.; MICROFICHE COPY AVAILABLE IN ENGINEERING. MIT copy bound with: Commuter transportation: problems and solutions / Thomas J. Cerny, III. 1964. -- A study of methods of determining the softness of toilet tissue / William Bedford Harper, Jr. 1964. -- Comparison of burning rates, pressures, and temperatures for solid propellants under controlled and uncontrolled burning processes / Dennis Lee Hinrichs. 1964. -- Effect of vacuum on sliding friction coefficient / Clarence Walter Malick. 1964. -- Feasibility study of an active vibration damping system / William Andrew Nelson, Junior. 1964. -- A method of estimating electric power costs for underdeveloped countries / Walter Thomas Norwich. 1964.; Includes bibliographical references (leaves 11-12).

Tramp shipping

Wed, 01 Jan 1947 00:00:00 GMT

Tramp shipping Long, Sumner Adam Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Marine Transportation, 1947.; Bibliography: leaf 101.

Using the Landau-Levich law to seal seams in waterproof clothing

Thu, 01 Jan 2015 00:00:00 GMT

Using the Landau-Levich law to seal seams in waterproof clothing Houston, Cole In high performance waterproof clothing, seam tape and welds fail before other parts of the garment. This paper examines a method of sealing seams in which the needle waterproofs the holes it creates by sealing them with a film of a thickness governed by the Landau-Levich law. The equation governing Landau-Levich behavior is combined with equations describing hole geometry to develop a phase space describing the fluidic and geometric properties necessary to seal a hole. A manual proof of concept test is performed which demonstrates that the basic method works. The needle speed of a standard sewing machine is then measured as is the size of the hole made by a standard sewing machine needle. These values are then used to calculate the viscosity of a fluid that will satisfy the conditions described by the phase space. An adhesive with the calculated viscosity is made and is used on a test bed to seal holes made by a needle. Each individual hole is sealed and further tests show that the seals are waterproof. Both the proof of concept and test bed experiments confirm the theory and it is concluded that needle speed, film length, and viscosity are the variables that can be controlled to tune hole sealing. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 19).

Impact of x-ray dose on the response of CR-39 nuclear track detector to 1-5.5 MeV alphas and 0.5-9.1 MeV protons for spectroscopy at the OMEGA Laser Facility and the National Ignition Facility

Fri, 01 Jan 2016 00:00:00 GMT

Impact of x-ray dose on the response of CR-39 nuclear track detector to 1-5.5 MeV alphas and 0.5-9.1 MeV protons for spectroscopy at the OMEGA Laser Facility and the National Ignition Facility Rojas, Jimmy A. (Rojas Herrera) The CR-39 nuclear track detector is used in many nuclear diagnostics fielded at inertial confinement fusion (ICF) facilities. Large x-ray fluences generated by ICF experiments may impact the CR-39 response to incident charged particles. To determine the impact of x-ray exposure on the CR-39 response to protons and alpha particles, a thick-target bremsstrahlung x-ray generator was used to expose CR-39 to various doses of 30 and 8keV Cu-K[alpha] and K[beta] x-rays. The CR-39 detectors were then exposed to 1-5.5 MeV alphas or 0.5- 9.1 MeV protons. The regions of the CR-39 exposed to x-rays showed a smaller track diameter than those not exposed to x-rays: for example, a dose of 3.0±0.1 Gy causes a decrease of (19±2)% in the track diameter of a 5.5 MeV alpha, while a dose of 6.0±0.1 Gy results in a decrease of (29±1)% in the track diameter of a 3.0 MeV proton. The reduced track diameters were found to be predominantly caused by a comparable reduction in the bulk etch rate of the CR-39 with x-ray dose. A residual effect, due to changes in track etch rate and dependent on incident particle energy, was characterized by an empirical formula. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, June 2016.; Page 47 blank. Cataloged from PDF version of thesis.; Includes bibliographical references (pages 45-46).

Measurement of optical properties of molten salts and metallic compounds for advanced solar and nuclear systems

Thu, 01 Jan 2015 00:00:00 GMT

Measurement of optical properties of molten salts and metallic compounds for advanced solar and nuclear systems Berdibek, Shapagat Renewable energies can reduce the dependence on fossil fuels. Solar thermal systems designed to use molten salts to directly absorb the solar heat are promising due to (1) potentially higher efficiency in capture of sunlight and (2) use of the salt to simultaneously capture sunlight and store heat in the salt. The optical properties of the molten salts are crucial for the design of such thermal systems because they determine the depth of the salt required to absorb sunlight and allow modeling of the performance of such systems. Molten salts are also being developed as coolants for high temperature reactors. Optical properties are also required to determine the radiative heat transfer of the coolant. The objectives of this thesis were to build a better system to measure these properties and measure the optical properties of the proposed salt for a direct absorption concentrated solar thermal system. The attenuation coefficient of light in a binary nitrate salt mixture (KNO 3-NaNO3 40-60 wt%) was measured over the wavelength range 833-2500 nm and the temperature range 300-400°C. This salt is the leading candidate for the first generation of a proposed concentrated solar power on demand (CSPonD) concept [3]. The relevant data was obtained using a FTIR spectrometer and an experimental apparatus designed for semitransparent liquids. The apparatus was validated using the published data for the attenuation of light in deionized water. The attenuation coefficients of the binary nitrate salt mixture for the lower wavelengths matched the data obtained by Passerini [1]. For the longer wavelengths, the attenuation coefficient peaked around 2.5 Pm as predicted by Drotning [2]. Since certain metallic components of solar and nuclear systems are exposed to the molten salt, it is important to characterize the behavior of their reflectivity in the presence of the molten salt. The reflectivity of 304L stainless steel was measured for the wavelength range 600-5000 nm at incident angles of light 10°, 40°, and 70° after an 8-day molten salt immersion test. The reflectivity was measured to be less than 10% for the solar spectrum. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2015.; "June 2015." Cataloged from PDF version of thesis.; Includes bibliographical references (page 29).

Meta-analysis of Tokamak reactor designs

Fri, 01 Jan 2016 00:00:00 GMT

Meta-analysis of Tokamak reactor designs Hernández, Manuel S. (Manuel Segundo) The long-term interest in nuclear fusion using tokamaks has yielded many published reactor designs. This study performs the first meta-analysis of tokamak reactor designs in an attempt to unveil new understanding not available in the traditional bottom-up method of looking at each design individually. Forty tokamak designs intended to produce significant fusion power at gains above one were identified in the published literature. Thirty-three important parameters describing a tokamak design were compiled by examining the set. The parameters from each design were extracted and placed into a database and plotted against each other to identify trends and outliers. Major outliers include two low aspect ratio designs and two He-3 reactor designs. Two classes are apparent in the database indicating two design philosophies: large major radius (~7 m), high power (~1.8 GW), and low density (~1 * 1020 m-3) designs utilizing superconducting magnets; and small major radius (~2.5 m), low power (~0.2 GW), and high density (~4* 1020 m-3 designs utilizing copper magnets. The former class has longer confinement times, higher plasma current, and lower magnetic field while the latter class tends to have lower gain, higher power per surface area, higher power per volume, and much smaller stored magnetic energies. Between the two sets, the non-dimensional plasma physics parameters are similar. These two basic design strategies have been in practice for the last 40 years. Since tokamak designs were first published, there has been little appreciable change in the mean and design envelope of the major parameters such as major radius, fusion power, magnetic field, and plasma current and of the plasma physics parameters such as beta, safety factor, temperature, density, and confinement time. The lack of significant change suggests that no major technological or physics breakthrough that could radically affect design philosophy has been discovered, and neither design philosophy has dominated. Trade-offs in triple product are apparent as all designs are at similar plasma temperature except He-3 reactors, while confinement time and density vary inversely among designs. The major dependencies on plasma current and size in the experimental confinement time scaling are also apparent. The conservatism inherent in reactor designs can be inferred from plasma physics parameters such as the confinement enhancement factor, normalized beta, and safety factor. The database indicates designers push all plasma physics limits simultaneously instead of individually. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 55-60).

Dwelling : a figural exploration of domesticity

Fri, 01 Jan 2016 00:00:00 GMT

Dwelling : a figural exploration of domesticity Perone, Francesca (Francesca E.) This thesis seeks to re-establish the necessity for specialized, figured spaces. Through the lens of the domestic sphere, the rooms become chambers of reflection, contemplation, and intimacy. The architecture is inspired by spatial hierarchies of carving, that is to say, labyrinthine undergrounds that are highly articulated through figure, and represent a sacred procession, a ritual, a journey. Historically, this introduces the spatial organizations of the Danteum, and of Peter Eisenman's house studies. The architecture is always reflective of an enfilade of discrete elements, highly idiosyncratic and articulated to show what lies within. The architecture is localized and intimate. The spatial reading of the space is to be recognized as being within a family of discrete figures, each one serving their inhabitants differently. This thesis is a counterargument to flexibility, as it stands rigidly within a grid, carved from the immaterial, an object in itself. Yet to preserve the sacred thresholds of each room, there are hints of animation, placements of objects that seemingly are derived from the will of the character. It is in this way that architecture informs space typologies, how life can be situated within figures as a microcosm, seemingly localized. Thesis: S.B., Massachusetts Institute of Technology, Department of Architecture, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 30).

Diffusional stability studies of a T91/12Cr-2Si-Fe functionally graded composite

Tue, 01 Jan 2013 00:00:00 GMT

Diffusional stability studies of a T91/12Cr-2Si-Fe functionally graded composite Morton, Sean (Sean C.) Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013.; MIT Institute Archives copy: incomplete; ends at page 7.; Includes bibliographical references (leaf 16 ).

Double streaming at 35 AU during the coronal mass ejections of March 1991

Thu, 01 Jan 2009 00:00:00 GMT

Double streaming at 35 AU during the coronal mass ejections of March 1991 Nampaisarn, Thanasin V We analyze data associated with the coronal mass ejections of March 1991, with emphasis on a remarkable double-streaming proton event observed at 35 AU. The plasma data used in our analysis were collected by three spacecraft: Voyager 2 near 35 AU, Ulysses near 3 AU, and IMP-8 at 1 AU. The observations of the same CME events by three spacecraft over such a wide range of radii gives insight into the evolution of CMEs as they propagate from the Sun to 1 AU and then into the outer heliosphere. Of the many characteristics observed, we are especially interested in the double-streaming proton events seen at Voyager 2 in June 1991 over a two day period. Such pronounced double-streaming has not previously been reported to be a feature of CMEs at any distance, much less at distances of 35 AU, with its 120 day transit time from the Sun. The double streaming events show a remarkably large separation between the two peaks that is close to the Alfvén speed and much greater than the thermal spread of either peak. These double streaming events were followed a day later by a large scale polarity reversal in the interplanetary magnetic field at Voyager 2. This reversal is thought to be a site of magnetic reconnection, where energy in the field is being converted into particle energy. We speculate that the free energy involved in the earlier double streaming events is somehow related to this magnetic reconnection process, although we have found as yet no direct causal connection. Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2009.; Includes bibliographical references (leaf 52) and index.

Design of a dredger for Pearl River

Mon, 01 Jan 1917 00:00:00 GMT

Design of a dredger for Pearl River Wu, Daiming; Yeh, Chi Foo; Tu, Hin Yung Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Naval Architecture and Marine Engineering, 1917.

An investigation of the relevant parameters of an exponential pile

Tue, 01 Jan 1957 00:00:00 GMT

An investigation of the relevant parameters of an exponential pile Knapp, Richard William Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Physics, 1957.; MIT copy bound with: The electrostatic support of suspended mass in a torsion balance / Julius Hyman, Jr. 1957.; Bibliography: leaf 35.

A student-faculty house for the Putney School, Putney, Vermont

Fri, 01 Jan 1954 00:00:00 GMT

A student-faculty house for the Putney School, Putney, Vermont Rogers, John B. (John Bateman) Thesis (B. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1954.; Accompanying drawings held by MIT Museum.

Negotiation strategies in American-North Korean nuclear talks, 1992-2013

Fri, 01 Jan 2016 00:00:00 GMT

Negotiation strategies in American-North Korean nuclear talks, 1992-2013 Brandt-Erichsen, Haley North Korea's relationship with nuclear technology has concerned the world for decades. A wide array of negotiation methods from punitive sanctions to energy assistance have been attempted to dissuade the nation from developing its weapons program -- but every resolution has been temporary at best. We focus on the United States' negotiation strategy and attempt to uncover inconsistencies between it and the material facts of the North Korean situation. The historical record of past negotiations and rhetoric used by each party during previous attempts are considered in our analysis, in order to construct a picture of diplomatic evolution over time. We believe that the North Korean bargaining position -- which has been highly consistent across decades of cyclic negotiating behavior -- is fundamentally incompatible with US demands for complete denuclearization. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2016.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 63-68).

Data processing and inference methods for zero knowledge nuclear disarmament

Fri, 01 Jan 2016 00:00:00 GMT

Data processing and inference methods for zero knowledge nuclear disarmament DeMaio, William (William Aloysius) It is hoped that future nuclear arms control treaties will call for the dismantlement of stored nuclear warheads. To make the authenticated decommissioning of nuclear weapons agreeable, methods must be developed to validate the structure and composition of nuclear warheads without it being possible to gain knowledge about these attributes. Nuclear resonance fluorescence (NRF) imaging potentially enables the physically-encrypted verification of nuclear weapons in a manner that would meet treaty requirements. This thesis examines the physics behind NRF, develops tools for processing resonance data, establishes methodologies for simulating information gain during warhead verification, and tests potential inference processes. The influence of several inference parameters are characterized, and success is shown in predicting the properties of an encrypting foil and the thickness of a warhead in a one-dimensional verification scenario. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2016.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 63-64).

Improvements to the Cheng-Todreas wire-wrapped rod bundle friction factor correlation in response to pin number and in the transition flow region

Fri, 01 Jan 2016 00:00:00 GMT

Improvements to the Cheng-Todreas wire-wrapped rod bundle friction factor correlation in response to pin number and in the transition flow region Kindfuller, Vincent John The Cheng-Todreas Detailed (CTD) Pressure Drop Correlation (1986) is the most accurate correlation for measuring the pressure drop of sodium coolant through a Sodium-Cooled Fast Reactor (SFR). Although CTD is the most accurate correlation, there is room for improvement with new data and modern ways to visualize data and check the accuracy of changes easily. This thesis attempts to offer a method for altering the CTD correlation to better account for changing pin numbers in SFR assemblies, and a better fit for the correlation to the data in the transition flow region between turbulent and laminar flow. Although CTD is more accurate than other correlations, it shows an inverse response to changing pin number in some geometries of bundle assemblies. In this thesis, a method is laid out to attempt to correct for that inverse response. Although no successful conclusion was reached, the thesis also offers a method for future attempts at improvement. In addition, a set of Matlab codes are offered that allow changes to be easily attempted and checked for validity. In addition, examining the data points of bundles in the transition flow regime shows possibilities for improving the accuracy of the correlation in that flow region. Two changes are implemented in this thesis: a change to the equation for the boundary between laminar and transition flow, and a change to the transition region friction factor equation. Both changes, when implemented, offer slight improvements to the overall accuracy and precision of the Cheng-Todreas Pressure Drop Correlation.. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2016.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 51-52).

Automating radiation damage studies of materials irradiated by high-energy protons using multiphysics simulations

Fri, 01 Jan 2016 00:00:00 GMT

Automating radiation damage studies of materials irradiated by high-energy protons using multiphysics simulations Ledoux, Gabrielle J Understanding radiation and corrosion damage in nuclear materials has become increasingly important in reactor design considerations. However, running irradiation damage studies in nuclear reactors is expensive and time-consuming. Thus, accurate, quick simulations have become more attractive to researchers studying alternative materials in nuclear reactors. This thesis investigates the possibility of automating irradiation damage studies using ion stopping range simulations coupled with heat generation simulations to find the change in temperature across a sample. The range simulations generate 1D slabs with different thicknesses and bombards them with high-energy proton beams. The slabs are automatically sorted, a meshed geometry is created, and the recoil energy information is entered into a multiphysics Finite- Element solver. Ultimately, the optimal beam current for which the temperature gradient across a coolant-sample geometry is less than 5 K is predicted. This thesis examines the possibility of automating the entire simulation process so that many materials and slab thicknesses can be tested for resistance to temperature change (and thus implying specifics of radiation damage effects). Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2016.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (page 81).

Radiation-induced bystander fibroblasts both reduce and amplify micronuclei induction through the reciprocal bystander effect and the secondary bystander effect

Fri, 01 Jan 2016 00:00:00 GMT

Radiation-induced bystander fibroblasts both reduce and amplify micronuclei induction through the reciprocal bystander effect and the secondary bystander effect Liu, Chang Aside from directly causing DNA damage, the traversal of radiation through cells also induces the bystander effect, which is the biological response of unirradiated cells that are neighboring or sharing medium with the irradiated cells. Although the mechanisms through which irradiated cells send signals to the bystander cells are not well understood, the bystander effect could potentially have clinical relevance or play a significant role in low dose radiation environments. The research in this thesis focuses on the ability of the bystander cells to influence the behavior of cells that share medium with them, which can be separated into three categories: unirradiated cells, irradiated cells, and the original irradiated cells that caused the bystander effect. These can be considered the "secondary bystanders." Human AG01522 fibroblasts were irradiated with 250 kVp X-rays and co-cultured with unirradiated fibroblasts to generate bystander cells, which were then cocultured with one of the three types of secondary bystander cells. The micronucleus assay was used to analyze the amount of chromosome aberrations present. In the unirradiated secondary bystander population, an increase in percentage of binucleated cells with micronuclei from the background level to approximately the level of the primary bystander cells was observed, indicating that bystander cells can send damaging signals. The data also showed that there was a lower frequency of micronuclei formation in the irradiated population with bystander inserts in comparison to irradiated populations without bystanders. However, there were no conclusive data on the effect of the bystander cells on other irradiated cells. Overall, the results suggest that bystander fibroblasts are capable of sending both detrimental and beneficial signals and can induce a range of behaviors in other cells. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2016.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 25-27).

Analyzing the Wien filters for the DANTE ion accelerator

Fri, 01 Jan 2016 00:00:00 GMT

Analyzing the Wien filters for the DANTE ion accelerator Ruprecht, Carolena Materials used in nuclear reactors, both fission and fusion, are continuously interacting with high energy ions. Tandem electrostatic accelerators, such as DANTE, are able to produce ions at high energies that can be used to simulate these interactions. In order to enhance the quality of experimental data taken using an accelerator, it is useful to ensure that the particles being accelerated are of the same species. Wien filters use electromagnetic forces to filter particles in an ion beam. Also referred to as mass selectors or velocity selectors, Wien filters operate on the principles of the Lorentz force in order to select ions of a certain mass while filtering out all others. The Wien filters in DANTE were modeled and tested in order to determine their effectiveness and ideal operating conditions. Experimental data was taken by varying the voltage applied to the Wien filters operating in DANTE. Preliminary results concluded that the Wien filters are able to steer the beam, as demonstrated by the impact of Wien filter voltage on the beam current through the accelerator. However, the experiment was inconclusive as to whether or not the Wien filters successfully filtered out unwanted ions. The settings applied during the experiment were then simulated with a model. For a deuterium beam, the model recommends voltage settings of 312 V and 341 V for the horizontal and vertical Wien filters, respectively. The model results are consistent with the experimental data. Recommendations for future work on this project are outlined following the results. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2016.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (page 45).

Computational treatments for neutron resonance elastic scattering in Monte Carlo nuclear simulations

Fri, 01 Jan 2016 00:00:00 GMT

Computational treatments for neutron resonance elastic scattering in Monte Carlo nuclear simulations Tran, Vivian Y Simulations are vital to the safe design and operation of nuclear reactors. It is therefore important that they accurately treat the physics of nuclear interactions. This work investigates the phenomenon of neutron resonance scattering with a moving target, which can affect the post-collision properties of the neutron and macroscopic values such as temperature reactivity coefficients. First, this research validates a faster computational treatment for resonance scattering--the accelerated resonance elastic scattering (ARES) kernel sampling method--against the already verified Doppler broadening rejection correction (DBRC) treatment in the open-source OpenMC Monte Carlo neutron transport code being developed at the Massachusetts Institute of Technology. In an effort to improve computational efficiency, the optimal energy limits where this phenomenon should be treated are determined and compared to the less costly but inaccurate approximation of assuming a constant constant cross section for determining the reaction kinematics. To reduce memory requirements and facilitate coupling with heat transfer, a new data representation was recently adopted in OpenMC based on the multipole formalism. However, this new approach invalidates the previous implementations of DBRC and ARES. This thesis thus developed a modified DBRC algorithm compatible with the new data representation. This new method is also validated against the previous DBRC method. While more computationally costly, the use of the multipole representation in treating resonance scattering reduces memory requirements by a hundred-fold and facilitates the representation of temperature dependent cross sections. Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2016.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (pages 58-60).

One size does not fit all : innovation in emergency housing with a focus on Nepal 2015

Fri, 01 Jan 2016 00:00:00 GMT

One size does not fit all : innovation in emergency housing with a focus on Nepal 2015 Voros, Jamie L Abstract Every year millions of people are displaced due to natural disasters and very primitive transitional shelters, or 't-shelters', exist to provide semi-permanent housing. Many t-shelter designs do not cater to all the needs of their inhabitants and are only functional in the short term, often leaving many people relying on t-shelters for housing in an unsafe and unsanitary environment. This thesis addresses the problem of people needing housing and of unsafe transitional housing by presenting a new design process and ultimately a t-shelter design specifically for the victims of the 2015 earthquakes in Nepal in the Kathmandu area. The process involves three key elements; identifying the specific needs of the displaced people, analyzing what materials and labor are available and ensuring that the shelter will be used as intended and therefore remain safe. The resulting shelter design harnesses the structural strength of the geodesic dome, the simplicity of reciprocal joinery and strong yet lightweight nature of bamboo. The effectiveness of the proposed new design process is demonstrated through checking the resulting shelter design meeting measurable outcomes like cost, structural integrity and skill level required to construct. Thesis: S.B., Massachusetts Institute of Technology, Department of Architecture, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 71-72).

To discover Hashima Island

Fri, 01 Jan 2016 00:00:00 GMT

To discover Hashima Island Lee, Dohyun, S.B. Massachusetts Institute of Technology From 1916 to 1945, Japanese governments recruited Korean laborers from South Korea for coal mining. The laborers ranged from thirteen to nineteen years old-most of them were still middle school or high school students. Hoping to earn money as the government promised, but unaware of the hostility and danger to which they would be exposed, 600 young Korean laborers were sent to an island called Hashima Island. Hashima Island has been desolate since 1974 after its coal resources were depleted. Although the island is no longer in use, the current condition of the architecture of Hashima Island speaks the truth of the history. The perimeter of the island is surrounded by walls; the laborers were never able to escape the hostile situation nor had a chance look at the world outside of the island. The wall is composed of three different layers: pre-cast concrete, rocks, and noise barrier; the wall as a whole is three-meters thick. Although the physical distance between the interior and exterior of the island is only three meters, the historical distance stopped in the thickness of the wall. The wall, which is the most problematic yet potentially useful component of the island, has to be interrupted architecturally in order to re-vitalize the timeline of the Korean laborers. My thesis is to reveal the neglected and hidden histories of Korean forced laborers in Hashima Island through intervention upon the existing walls. By creating an outdoor city museum by transforming the wall, the architecture of the island is re-discovered. The wall is punctured, chiseled, carved, and shaped to create an episodic and linear path along the wall and to be in communication with the surrounding water, mountains, and ultimately the users. The wall allows water to overflow into the site, delineating the lowest topography, and provides access to the underground basement dormitories of the Korean laborers. The wall is no longer a static barricade; it performs as a moving network among the existing materials of the island and the visitors. Thesis: S.B., Massachusetts Institute of Technology, Department of Architecture, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 55).

Urban building energy modeling and retrofit design as a means to inform effective public policy : Boston case study

Fri, 01 Jan 2016 00:00:00 GMT

Urban building energy modeling and retrofit design as a means to inform effective public policy : Boston case study Irani, Ali(Architect), Massachusetts Institute of Technology Residential buildings use upwards of 20% of the total energy consumed annually in the United States. This, coupled with the desire to reduce overall utility costs and improve occupant comfort on the part of residents, places cities, as the main catalyst for local energy policy, at the forefront of the drive for a more sustainable built environment. This thesis seeks to explore the potential savings associated with energy retrofits in selected neighborhoods in the city of Boston, by developing a comprehensive urban energy model and implementing two retrofit strategies. As part of the methodology, this thesis will combine GIS data with building construction, use, and equipment data to develop a quick, accurate, and adaptable energy simulation model. By combining the findings of the simulation with socio-economic indicators such as income level and ownership type, this thesis will examine how to best implement the selected building retrofit strategies. Of particular interest, is the idea of an annual adoption rate for a particular strategy and the perceived effects of socio-economic indicators on the actual adoption. Ultimately, the findings of this thesis will enable a thoughtful discussion of the effective implementation of public policy and serve as a guide for further investigations focusing on the demographics of urban energy use. Thesis: S.B., Massachusetts Institute of Technology, Department of Architecture, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 41-42).

Improving mental wellbeing on college campuses through participatory art installation

Fri, 01 Jan 2016 00:00:00 GMT

Improving mental wellbeing on college campuses through participatory art installation Han, Sonya Lei In recent years, the mental wellbeing of the students and faculty here at MIT has generated a lot of discussion, both on campus and in the press. In response to this, a large number of student-lead and institute-lead mental health initiatives have been launched, promoting conversation and acceptance, and providing a wide range of social and medical resources. However, can we further supplement our community's mental wellbeing through altering our physical surroundings? This thesis draws on precedent research and case studies in the fields of psychology, biology, and art, and combines it with site-specific observational studies of student life on campus. The culmination is the proposal and implementation of a public art installation that uses properties of soil, nature, and customizable components that users can interact with. This installation aims to improve the mental wellbeing of the community at MIT and/or anyone who comes into contact with the art objects through different modes of active interaction and passive interaction. The thesis concludes with an examination of the installation and a discussion of the feedback gained from users as well as observed behaviors exhibited in relation to the objects. Thesis: S.B., Massachusetts Institute of Technology, Department of Architecture, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 45-46).

Illuminating education : composition and use of lighting in public K-12 classrooms

Fri, 01 Jan 2016 00:00:00 GMT

Illuminating education : composition and use of lighting in public K-12 classrooms Ballina, Mariana Despite ample research on light's effect on the human body (and particularly its effect on student and teacher health and performance), understanding of light's role in operational energy consumption, and advancement made in architectural design to address these impacts, little is known about actual use patterns and occupant exposure to light in classroom settings. Through the measurement of lighting conditions and an examination of occupant behavior under both electric and natural lighting systems in K- 12 schools of Southern California, this research aims to bridge gaps between knowledge of light's impact on the human body and results of human exposure to various light as well as our understanding of occupant use and the current architectural design of schools. An analysis of illuminance and color temperature measurements across 21 classrooms, observations, and questionnaire responses from 27 teachers reveals muted daylight availability and low and warm color electric lighting conditions in the classroom that consistently falls below recommended illuminance and light levels, as well as lighting controls, installations, and design that may not allow for adequate control within these rooms by occupants. The work presented informs future design choices and assumptions made by architects of K- 12 schools, and may provide context for research on and estimates of light's biological impact on students. Thesis: S.B., Massachusetts Institute of Technology, Department of Architecture, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 101-102).

The properties of ramie fabric as covering for airplane wings

Thu, 01 Jan 1920 00:00:00 GMT

The properties of ramie fabric as covering for airplane wings Moy-Ding, William; Chun, Ki Kee Introduction: The coming commercialization of aircraft has led to the investigation of many constructive textile fabrics - Silk, linen, and cotton fabrics are used most commonly. On account of the high cost, the use of silk and linen is limited to a great extent. today mercerized cotton fabric plays the predominating part in the construction of airplane wings. The object of this experiment is to investigate the physical properties of ramie for its possible entering into the realm of its sister fabrics. Ramie is a fiber obtained from the base of the stingless nettle or Baehmerica tenncissima, which grows best in tropical and sub-tropical countries. The plant is a shrub, reaching four to six feet in height, and is very hardy. It is largely cultivated in China and India. In China it is cultivated in Hupeh, Szechuen Kiangsi, and Kwangtung. In Kwangtung, the local product is made into glass cloth. (Appendix IV) The piece of ramie fabric used in this research was imported from China. The fiber is white in color, but not very elastical and flexible. It can be separated as fine as silk. Its surface is smooth and regular. On this account it lacks cohesion and does not adhere to each other. Thesis: B.S., Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1920. [first author].; Thesis: B.S., Massachusetts Institute of Technology, Dept. of Business and Engineering Administration, 1920. [second author].; Includes bibliographical references (leaf 41).

Radial equilibrium of toroidal plasmas.

Thu, 01 Jan 1976 00:00:00 GMT

Radial equilibrium of toroidal plasmas. Pickrell, M. M. (Mark Manley) Thesis. 1976. B.S.--Massachusetts Institute of Technology. Dept. of Physics.; Microfiche copy available in Archives and Science.

Design, development, and fabrication of a vibration detecting robotic foot-pad using embedded PVDF strips

Fri, 01 Jan 2016 00:00:00 GMT

Design, development, and fabrication of a vibration detecting robotic foot-pad using embedded PVDF strips Abdolrahim Poorheravi, Negin This thesis shows the design, fabrication, and early characterization process of a slip-sensing foot-pad made from PVDF strips embedded in a rubber molded structure. What follows suggests a proof-of-concept for a design that can be used to detect vibrations on the edges of a teethed structure. The ability to detect localized vibrations in the embedded PVDF sensors in this foot-pad can be used in future studies to measure the contact-patch area and investigate the relationship between the change in such area and incipient slip. The future iterations of the proposed foot-pad can be used to integrate with current foot-pads worn by legged robots such as MIT Cheetah to enable them to predict slippage. An experimental procedure was used to find the effect of a localized stress on the embedded sensors' data. Three iterations of the foot-pad were designed and fabricated. Furthermore, a custom slippage tester was designed and built for future studies. The experimental results suggested that the effect of triggering on the foot-pad was highly localized since it did not affect neighboring sensors. This behavior can be used to measure changes in the contact-patch area since loss of contact between the ground and foot-pad introduces vibrations on the edges of the pad. Though further data collection and mapping should be conducted for this foot-pad to be able to predict slippage, the experimental results suggest that usage of urethane embedded PVDF sensors can be a viable and promising approach in achieving this goal by detecting the localized vibrations induced by the slip incident. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 31).

Introduction to kinetic sculpture : a one-week course for middle school students

Thu, 01 Jan 2015 00:00:00 GMT

Introduction to kinetic sculpture : a one-week course for middle school students Suresh, Martin R. (Martin Ravindra) A one-week course in kinetic sculpture was designed to introduce middle school students to the marriage of art and engineering. Because art can appeal to different sensibilities than engineering alone, it can serve as a means to broaden perspectives of students with different motivations. In light of increasing emphasis on the development of programs in STEM (Science, Technology, Engineering, and Math) in U.S. education, this project fills a need for more opportunities in STEAM (Science, Technology, Engineering, Arts, and Math). Even though the availability and popularity of STEAM programs for children is growing, these opportunities for young children are still limited. Therefore, there is a market for a course that incorporates art and the engineering design process like this one. Daily activities in an introductory week-long kinetic sculpture course are defined. Each day's lessons are provided along with resources for further study. The structure of the course is based on sound pedagogical practice. The strength of the course is its ability to incorporate science and art in a fun way that will be appealing to students. Future work would consist of the expansion of the lessons with more detail for teachers and the addition of more alternate activities. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 49-50).

Improving the concentrated solar power plant through connecting the modular parabolic solar trough

Fri, 01 Jan 2016 00:00:00 GMT

Improving the concentrated solar power plant through connecting the modular parabolic solar trough Abiose, Kabir Concentrating solar power (CSP) stands as a promising renewable energy technology with the ability to contribute towards global reduction of carbon emissions. A major obstacle to increased adoption of CSP plants has to do with their high initial investment cost; consequently, there is a powerful desire to find improvements that decrease the initial capital investment for a CSP plant. One such improvement involves connecting modularized parabolic trough segments, each with the same dimensions, decreasing the overall amount of actuators required along with greatly simplifying system control architecture. This thesis is concerned with the extent to which parabolic solar trough modules can be connected together while still being able to operate to desired accuracy under expected load. Accuracy requirements are calculated, along with expected loads resulting in frictional torque on the trough. These expected loads are combined with a model for the effect of connecting multiple trough modules to generate a relationship between number of chained modules and required torsional stiffness. To verify said model, an experimental setup was designed and constructed to simulate loads due to both trough weight and wind loads. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.

Characterization of synchronizer performance for a clutchless transmission

Fri, 01 Jan 2016 00:00:00 GMT

Characterization of synchronizer performance for a clutchless transmission Antonini, Amado Synchronizers are a ubiquitous component of almost every type of transmission in modem vehicles. They are mechanical devices whose function is to ensure that components rotating at different rates can be harmonized smoothly and without eroding their surfaces. They are responsible for both the durability of the transmission and the comfort of the passengers. This work analyzes the capabilities and limitations of synchronizers to be used in a novel transmission. It is a contribution to a larger project whose goal is to develop a hybrid, clutchless transmission for a performance vehicle that will improve efficiency by eliminating the friction and mechanical losses inherent in a traditional clutch. An overview of the synchronization process is presented followed by a simplified mathematical model of the common baulk-ring synchronizer. The model is experimentally validated in order to make predictions of the device's performance on the new transmission. Several simulated scenarios are then developed that provide information that is critical for designing synchronizers for the clutchless transmission. Matlab code was developed for these simulations and is provided at the end for replication of the results. Considering the demanding environment under which the synchronizers are expected to operate in the clutchless transmission, the possible failure modes of the synchronizer components are investigated. Finite element analysis (FEA) is used to predict the maximum loads on the synchronizer ring before the material yields. An energy analysis is also performed to ensure that the energy dissipation rate of the friction surfaces is adequate. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 50-51).

Effect of feed temperature on the performance and properties of the NF270 membrane

Fri, 01 Jan 2016 00:00:00 GMT

Effect of feed temperature on the performance and properties of the NF270 membrane Bolaji, John O. (John Olaoluwa) An experimental study was done to explore the effect of feed water temperature on the properties and performance of nanofiltration membranes. The NF270 membrane was selected for this study, in which two temperatures of feed solution were passed through the membrane and water flux and salt rejection were measured. Results from fitting with experimental data show that water flux increased 23% and salt rejection changed minimally from 25°C to 40°C. A numerical fitting method used the experimental data to determine the parameters of the membrane: pore radius, effective active layer thickness, and volumetric charge density. From 25°C to 40°C, the fitted parameters showed a 29% increase in pore size, and an 84% increase in effective active layer thickness; volumetric charge density increased in magnitude by approximately 64%. Pre-compaction and pre-soaking the membrane in alcohol are two separate membrane pretreatment procedures that showed significant effects on the performance of the membrane. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 35).

Analysis and design of a Formula SAE powertrain

Fri, 01 Jan 2016 00:00:00 GMT

Analysis and design of a Formula SAE powertrain Bray, Samantha (Samantha Jo) This thesis will analyze the MIT Formula SAE car to determine performance of our current and future cars. The conclusion of this analysis will drive the powertrain decisions for our Model Year 2017 (MY 17) and other future cars. Very little data relating to our cars currently exists, but is vital to proper design; therefore, that is the first step of this thesis. After current performance has been gaged, the next step will be determining a motor that will optimize vehicle performance for competition. From this our team could use either two motors with an electronic differential or one motor with a limited slip differential. Tangential to determining motors, analysis will also be done to determine whether chains or a planetary gear system would be more optimal for connecting the motor output to the rear wheels. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 23).

Simulations of a three degree of freedom brachiating Y-bot robot

Fri, 01 Jan 2016 00:00:00 GMT

Simulations of a three degree of freedom brachiating Y-bot robot Breton, Alexander (Alexander G.) Brachiation is a means of locomotion for lightweight apes like gibbons. It involves the animal swinging its arms to gain moment and swing forward. A large amount of research has been done studying a simplified two-link two DOF robot, named "acrobot" by Mark Spong. While the problems of this robot have been studied extensively, it's functionality is quite limited. This paper studies a three-link three DOF brachiating robot, dubbed "Y-bot". The goal of adding the extra link is to add functionality. Simulations of a model were run in Matlab taking advantage of Russ Tedrake's toolbox Drake, which was designed to solve optimization problems of underactuated systems. The main method used in the trajectory optimization was direct collocation. The task of the robot in the simulations was to swing from a one "branch" point to another. The trajectories of two Y-bot models swinging from rest were optimized. Furthermore, the gait of one of the models was examined, and a beneficial state for the second swing of a gait was suggested. A method to optimizing the gait of a model was proposed. A linear relationship between the total trajectory time and the scale of the model was defined. The paper suggests a physical model of the Y-bot could be constructed using Saito's two DOF brachiating robot as a benchmark. The problems of gait optimization and payload transportation were mentioned as future work to be done. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages [23]-[24]).

Investigating the trade-offs involved in augmenting a DC brushless motor with an active heat sink in order to improve performance.

Fri, 01 Jan 2016 00:00:00 GMT

Investigating the trade-offs involved in augmenting a DC brushless motor with an active heat sink in order to improve performance. Browne, Deron Adriel This thesis seeks to establish solutions to the issue of electric motor heating and the problems it presents for use of these motors in biomechatronic applications. As electric motors are used, their windings heat up and the resulting temperature limits torque. Larger motors may be used to obtain more torque, but this adds undesirable weight to the devices in which they are used. Cooling methods also exist, but do not necessarily consider suitability to bionic applications. This thesis therefore aims to improve the torque output of a given motor by effectively removing heat while minimizing the addition of mass. I hypothesize that the torque density of an EC-4 pole 30 48V Maxon DC brushless motor can be improved by augmenting it with an electronics fan and an annulus. Results showed that the housing to ambient thermal resistance of the motor was decreased by 68% from the experimentally found value of 11.5KW-3 to a value of 4.03KW- 3 by using a 4.72 x 10- 3 m3s-1 (10 cfm rated) electronics fan. The projected torque density of the motor was also found to be maximally improved from 0.382Nmkg-1 to 0.393Nmkg-1. These results were obtained under the assumptions that the motor could be reasonably represented by its brushed counterpart and that parallel plate fluid dynamics closely approximates annular fluid dynamics. While more investigation is necessary to fully validate the results, they do show that there is potential for using simple methods to significantly improve the torque density of small electric motors. It is possible then that added mass can work to noticeably improve motor performance. There is therefore scope to improve the use of these motors in biomechatronic devices. Smaller, more efficient motors will decrease the weight of these devices and improve their overall efficiency. Bionic devices will thus be one step closer to better mimicking human capability. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 53).

Casting a one-lunger Atlantic marine engine

Fri, 01 Jan 2016 00:00:00 GMT

Casting a one-lunger Atlantic marine engine Castellanos, Samantha Nicole Fabrication of a one-lunger Atlantic marine engine for the purposes of developing a curriculum for an advanced fabricating and machining class for the Papplardo Apprentices at MIT. One-lunger marine engines greatly influenced the fishing cultures of Nova Scotia at the turn of the 20th century. Discussion of proper casting practices and terminology in addition to theory of sand types, machinability, engine cycles, and ignition systems. In depth descriptions of basic and advanced casting processes using the ignitor body and piston as examples. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 39).

Mechanical and trajectory design of wearable Supernumerary Robotic Limbs for crutch use

Fri, 01 Jan 2016 00:00:00 GMT

Mechanical and trajectory design of wearable Supernumerary Robotic Limbs for crutch use Cheung, Michael Yanshun The Supernumerary Robotic Limbs (SRL) is a wearable robot that augments its user with two robotic limbs, kinematically independent from the user's own limbs. This thesis explores the use of the SRL as a hands-free robotic crutch for assisting injured or elderly people. This paper first details the mechanical and material design choices that drastically reduced the weight of this SRL prototype, including advanced composite materials, efficient joint structure, and high-performance pneumatic actuators. The latter half of this paper characterizes the biomechanics of both traditional crutch-assisted and SRL-assisted ambulation, models this gait pattern with an inverted pendulum system, and derives equations of motion to create a simulation that examines the effect of various initial parameters. Finally, an optimum set of initial parameters is identified to produce a successful SRL-assisted swing. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 22).

Elastic stretchable optical fibers

Fri, 01 Jan 2016 00:00:00 GMT

Elastic stretchable optical fibers Cholst, Beth (Beth Ellen) The utilization of soft materials in the design of optical systems provides opportunities for imparting these optical systems with completely unprecedented properties. This will enhance performance of systems, such as optical fibers, and enable new application scenarios. Here, we report the design, manufacture and characterization of elastic stretchable optical fibers. Analogous to conventional optical fibers, the elastic fibers consist of a high index core, made from a polystyrene-polyisoprene triblock copolymer, and a low refractive index cladding, formed by a fluorinated thermoplastic elastomer. The fibers are manufactured by co-extrusion of their constituent materials. They can be stretched to 300% strain repeatedly. Axial deformation of the fibers results in a variation of their light guiding properties. The fibers' attenuation coefficient was determined to be 0.021 ± 0.003 dB/mm, which is 2 orders of magnitude higher than for standard optical glass fibers. The high attenuation coefficient is likely due to scattering of light by air inclusions incorporated during manufacturing at the core-cladding interface. The fibers elastic modulus is 960 ± 280 kPA and their yield strength lies in the range of 2150 ± 480 kPA. The variation in intensity of guided light as a function of strain applied axially to the fibers was measured with a customized optical setup. Our experiments show that elastic optical fibers have properties that make them desirable as mechanical sensors and components in a range of other applications, provided current manufacturing shortcomings are addressed. The fibers could be used for light delivery to individual pixels of flexible deformable displays. They could be incorporated into clothing for delivery of light for display purposes or textile-integrated photonic circuits to create functional textiles. Because the fibers can stretch, the textiles or displays will be able to undergo deformation without damage or loss in performance. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 23-24).

Ghanaian entrepreneurship and innovation

Fri, 01 Jan 2016 00:00:00 GMT

Ghanaian entrepreneurship and innovation Connors, Grace (Grace B.); Press-Williams, Jessica This study explores local innovation and entrepreneurship in Ghana. It presents the results of 28 in-person interviews with Ghanaian entrepreneurs who live and work in four cities across Ghana. The interviews detailed the entrepreneurs' business endeavors, backgrounds, and thoughts regarding Ghanaian innovation and entrepreneurship. The interview data was supplemented with a statistical analysis in order to observe trends among the entrepreneurs, and the main findings offer some insight into Ghanaian entrepreneurship. Overall, the interview participants found it relatively easy to start businesses in Ghana, and started businesses for a variety of reasons, which included a deficit of currently existing jobs and the desire to solve a local problem in an entrepreneurial way. In addition, the makeup of the businesses varied, and many included both a for-profit and philanthropic arms. The philanthropic arms of businesses also varied in terms of focus and informativeness. Although the cities in which the entrepreneurs are situated are very different, geography did not seem to impact the businesses' focus overall. The study also investigated the relationship of entrepreneurship to innovation in Ghana. Overall, we determined that entrepreneurship in Ghana does not always mean that innovation is occurring, and that many entrepreneurs seemed limited in their capacity to innovate. The study identifies several barriers to innovation in Ghana, including a lack of capital, infrastructure challenges, and an entrenched system of apprenticeship. Within the bounds of the study, the more innovative businesses tended to be headed by entrepreneurs who were more highly educated, and businesses with more innovative philanthropic arms tended to be started by entrepreneurs with more clearly-defined role models. The results of this study are not representative of the whole pool of Ghanaian entrepreneurs because the interview participants were not selected rigorously. The findings are intended to be used as guidelines for future work relating to entrepreneurship and innovation in Ghana, and potentially other developing countries. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 85-86).

Forces and time delay due to impact with gates in ski racing

Fri, 01 Jan 2016 00:00:00 GMT

Forces and time delay due to impact with gates in ski racing Fitzgerald, Meaghan (Meaghan E.) In an effort to better understand impacts with gates during ski racing competition, on-snow measurements and observations were made of both standard gates and inflatable gates. These observations highlighted the importance of impact force and time. Two additional experiments were done to analyze these factors and compare their values for standard gates and inflatable gates. Gates were hit with a controlled weighted pendulum and force sensor to measure the impact force. To measure time, slow motion footage was taken of the gates clamped in a baseball pitching machine. The baseball's velocity was scaled to model the skier using conservation of energy principles. The footage was analyzed with position tracker software. Inflatable gates were found to have a lower mean impact force of 28.55 ± 5.89 N compared to the standard gate impact force of 44.55 ± 7.12 N. Although they exhibited lower impact force, the inflatable gates had a longer time to clear out of the skier travel path due to isolated bending in the small area of impact. The time for the tip of the inflatable gate to clear was 0.63 ± 0.1s compared to the 0.43 ± 0.03s it took for the tip of the standard gate to clear. From these results, it can be concluded that inflatable gates have a softer impact force, but require a modification in racing form in order to increase the impact area and thus decrease momentum and balance losses due to gate bending around extremities. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 37).

Effectiveness of grips at minimizing vibrations during field hockey hits

Fri, 01 Jan 2016 00:00:00 GMT

Effectiveness of grips at minimizing vibrations during field hockey hits Gulliver, Morgan (Morgan E.) An experiment was carried out in order to determine the frequencies experienced in two locations on the stick during two different field hockey hits, the push and the strike. The results from these experiments showed that the top hand during a hit experiences a higher resonant frequency. During the push the top hand experienced an average resonant frequency of 349.1 Hz, compared to the lower hand which experienced an average resonant frequency of 43.95 Hz. During the strike the top hand experienced an average resonant frequency of 197.8 Hz, compared to the lower hand which experienced an average resonant frequency of 24.41 Hz. A second experiment was carried out in order to determine how effective the grip was at dissipating frequencies. The results determined that the grip is most effective over the frequencies of 117 Hz-470 Hz. Both an old and new grip were tested. The new grip was slightly more effective over the frequencies of 117 Hz - 235 Hz, and similar over the frequencies 250 Hz - 470 Hz. From these experiments it was concluded that field hockey grips are most needed and effective on the shaft of the field hockey stick. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 30).

Thermal and hydraulic analysis of the adsorption bed of the adsorptive thermal battery

Fri, 01 Jan 2016 00:00:00 GMT

Thermal and hydraulic analysis of the adsorption bed of the adsorptive thermal battery Haskaraman, Feyza Electric vehicles (EVs) have a drawback of relatively short drive range that affects their adoption rate. In order to increase the drive range of EVs, replacing heating, ventilation and air conditioning (HVAC) system with a novel absorbent system of materials and methods is widely investigated. This work focuses on the analysis of the design of such a system to suggest efficiency improvements. The thermal insulation and choice of pump required for the optimal function of the adsorptive bed that carries the novel material are analyzed respectively to understand system performance. A thermal resistance analysis was performed in order to understand the undesirable heat loss from the system that decreases the efficiency. Moreover, pressure loss in the piping system was determined theoretically to choose a compatible pump. This analysis also resulted in a modular code that can be used to test different design parameters for future work, Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 23).

Design, development, and characterization of an experimental device to test torsion-controlled fracture of thin brittle rods

Fri, 01 Jan 2016 00:00:00 GMT

Design, development, and characterization of an experimental device to test torsion-controlled fracture of thin brittle rods Heisser, Ronald Henry As research continues to uncover the many different physical properties of meso- and microscale materials, it becomes more evident that these materials often behave in counterintuitive ways. Characterizing unique phenomena not only provides analogies in nature which inspire innovation at all levels of research and design but also presents new possibilities for future technological development. The discussion presented herein explores the design and development of a low-cost, manual device intended to test a hypothesis rooted in the behavior of breaking pasta that intrigued even Richard Feynman. While the mechanism for why spaghetti breaks into three or more pieces has been described, the experimental discussion presented here focuses on the effect that added torsion has on the fracture bent spaghetti. Specifically, it is possible that twisting the spaghetti a critical angle and bending it will cause it to fracture into only one piece. The idea of torsion being used to exhibit some control over how a material fractures has not been well-investigated; the results which come from this experiment may prove useful for applications even beyond the scope of thin brittle materials. With this said, the sensitivity in quantifying breaking from torsion and bending together requires that the experimental device prevent systematic error stress from negatively impacting the accuracy of the experiment. Thus much time is devoted to explanation and rationale behind the analysis of the experimental device. Alongside the device's characterization this thesis serves to be a reflection of the design process taken while creating this device. Lessons learned from this project are included in all aspects of the discussion and a section in the Appendix is devoted to a more detailed account of the design and fabrication of one device component. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 40).

Characterization of whip targeting kinematics in discrete and rhythmic tasks

Fri, 01 Jan 2016 00:00:00 GMT

Characterization of whip targeting kinematics in discrete and rhythmic tasks Henrot, Camille (Camille Ida) Robotic control of complex objects is inferior to that of humans despite superior communication, sensors and actuators. Therefore, studying human control of complex dynamic objects, in particular a bullwhip, should reveal how humans may achieve superior dexterity. An expert whip-cracker performing two distinct targeting tasks, discrete and rhythmic, was observed using the Qualisys 3D motion capture software. The objective was to investigate the kinematics of the whip, the kinematics of the subject's arm while controlling the whip and the differences between discrete and rhythmic tasks. The subject was able to expertly perform both targeting tasks with excellent targeting accuracy. The study confirmed the existence of a wave propagating down the whip as stated in prior work. Furthermore, a distinct difference between discrete and rhythmic tasks was observed in the reproducibility of position profiles, reproducibility of phase profiles, and the waveforms of elbow and wrist angles. Finally, the whip trajectory was substantially confined to a plane. In contrast with claims made in prior work, this plane was found to be distinct from the parasagittal plane and slanted with respect to it. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 45).

Design and fabrication of a solar-powered Bluetooth Low Energy device

Fri, 01 Jan 2016 00:00:00 GMT

Design and fabrication of a solar-powered Bluetooth Low Energy device Ishiguro, Amy (Amy S.) A device was built within the MIT Photovoltaic Laboratory that obtains power from solar cells, collects temperature data from a sensor, and sends the data to a phone application via Bluetooth Low Energy (BLE) wireless technology. BLE is suited for use with solar technology because of its low energy consumption. Although limited to small data packets and a range of a few dozen meters, such a device has many potential applications in the near future. The same device architecture can be modified to suit a variety of applications by interchanging current components with those suited for the intended design application. The adaptability of this device architecture, combined with further advances in solar cell technology and a low-power approach, increases the commercialization prospects of small solar-powered devices. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 30-32).

Comparison of user metabolic efficiency between traditional and spring assisted leveraged freedom chair models

Fri, 01 Jan 2016 00:00:00 GMT

Comparison of user metabolic efficiency between traditional and spring assisted leveraged freedom chair models James, Bassey Henry Tests were performed to determine how the use of an elastic energy storage mechanism on the Leveraged Freedom Chair would affect the rider's metabolic efficiency. For this test, elastic bands were attached to the levers, and the rider's heart rate was recorded as he rode multiple lengths of a field in a timed trial, in both the spring assisted LFC and the traditional LFC. Efficiency in the spring assisted LFC, normalized by the efficiency measured on the traditional chair, was found to be [epsilon]n = .684. This may indicate that there is a higher metabolic cost associated with pulling than with pushing in the LFC. The lower efficiency may also have resulted from the arbitrary choice of spring constant, as well as viscoelastic losses in the elastic bands. The user experienced much higher fatigue in the traditional LFC, primarily in the latter half of the 887 meter course, suggesting that in spite of the current decreases in efficiency, the spring system could add value by allowing users the option to travel longer distances. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 31).

The MIT Movement Project

Fri, 01 Jan 2016 00:00:00 GMT

The MIT Movement Project Jiang, Christine W. (Christine Wei) We present an experimental study investigating trends in the Massachusetts Institute of Technology's physical activity patterns and factors affecting activity levels. Physical activity was measured using steps taken per day and the study was conducted using historical and collected data of 20 subjects. Step data was measured and stored in the iPhone Health application and submitted through a custom MIT Movement Project iPhone application. The results showed a correlation between steps taken and day of the week, with fewer steps being taken towards the middle of the class week. Additionally, steps variations occurred during major holidays and events. Temperature and rainfall also relate to steps taken with higher temperatures and less rain correlating with more steps taken. Furthermore, individual factors also affected an individual participant's daily step count. Higher stress levels correlated with fewer steps taken and less activity overall while fewer hours of sleep led to increased number of steps per day, likely due to the larger number of awake hours. To further increase physical activity levels on its campus, we recommend that MIT investigate the possibility of specific campaigns to target low-activity level time periods and look to expand its physical education programs for all members of its community. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 22-23).

Self-installation of drip irrigation emitters for prototype emitter testing

Fri, 01 Jan 2016 00:00:00 GMT

Self-installation of drip irrigation emitters for prototype emitter testing Johnson, Eric (Eric M.) In this thesis, I tested methods of adhering factory-made drip emitters to the interior of short segments of piping. Different types of adhesive and pipe material combinations were tested, and I selected three combinations for further testing. Performance similar to factory-installed drip emitters was achieved at low pressure, but the necessary watertight seals repeatedly burst at higher water pressures. Alterations to the drip emitter and installation procedure are recommended to increase reliability and resilience of the installation. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 31).

Replacement of an active metatarsophalangeal joint with a passive spring-damper system for implementation in an ankle prosthesis

Fri, 01 Jan 2016 00:00:00 GMT

Replacement of an active metatarsophalangeal joint with a passive spring-damper system for implementation in an ankle prosthesis Kline, Eric S Analytical modeling was used to determine the optimal configuration of a replacement metatarsophalangeal (MTP) joint to be used in a prosthetic ankle. A spring was added to the joint to store energy and release it during the part of the gait cycle where the highest torque is required, reducing the torque the motor must exert. A linear spring-damper system adapted for use on a rotational joint was found to exhibit similar behavior to the biological joint for the range of motion required. The optimal gear ratio for the ankle motor, spring constant, and damping constant for the MTP joint were found using a MATLAB program written for this purpose. A physical prototype was fabricated, and testing was performed on an Instron machine to validate the results. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 22).

Exploring and evaluating methods of actuating an active lens

Fri, 01 Jan 2016 00:00:00 GMT

Exploring and evaluating methods of actuating an active lens Kwok, Christopher (Christopher L.) Active lenses today have a variety of uses from photographic capabilities in small mobile devices to applications in engineering. They provide faster response times and higher portability and efficiency when compared to their traditional lens assemblies. For this project, I have evaluated two different methods of active lens actuation: using an electromagnetic actuator and using an electroactive polymer. From testing each method's abilities, it was found that the electromagnetic actuator, though robust in design poses issues over long-time use. The electromagnetic actuator was able to generate a focal power range of 11.9 to 19.2 diopters (52 to 84mm focal length range), but a high power consumption led to problems with heating the internal components of the active lens assembly. In the EAP method, a lower power consumption proved to be a viable option for actuation, and through testing and calculation, it was determined to be useful in application. However, a proposed efficient design must be further explored. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 24).

High-throughput extrusion additive manufacturing using electrically resistive preheating

Fri, 01 Jan 2016 00:00:00 GMT

High-throughput extrusion additive manufacturing using electrically resistive preheating Malinowski, Maxwell X. (Maxwell Xavier) Extrusion-based additive manufacturing, commonly known as fused deposition modeling (FDM) or fused filament fabrication (FFF) is incredibly useful in industry for a variety of reasons, including rapid prototyping and the ability to create complex geometries easily. However, its further adoption is limited by relatively slow part manufacturing rates when compared to conventional manufacturing methods. Previous work has identified three modules within the FDM process which are rate limiting: speed of gantry positioning, polymer heating, and extrusion pressure. Advancements in any one module will allow for higher volumetric output, which will in turn allow for higher rates of production using FDM. This work focuses on polymer heating, and demonstrates a new concept for rapid heating of filament by introducing conductive nanoparticles into the polymer resin and resistively heating sections in flow. This technique can improve the volumetric output of FDM printers by at least 20%. First, the resistive properties of the composite filament are characterized. Second, the concept is experimentally validated by demonstrating a decrease in extrusion force required to maintain a given feed rate when using resistive heating. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 33).

Design and testing of a flexible exoskeleton-to-shoe interface

Fri, 01 Jan 2016 00:00:00 GMT

Design and testing of a flexible exoskeleton-to-shoe interface Leibowitz, Dalia A lightweight minimalist lower-limb exoskeleton has been designed that reduces the metabolic cost of walking. Currently, this exoskeleton must be permanently attached to a shoe; holes are drilled into each new shoe used, a practice that is neither flexible nor cost-effective. A new attachment system is proposed to temporarily but securely connect the exoskeleton to shoes of various sizes. This exoskeleton-to-shoe interface is lightweight, adjustable for various shoe sizes, and easy to attach and remove. This interface is meant to increase the testing flexibility and commercial potential of the exoskeleton. After the interface was designed and built, the stiffness of the interface was measured and compared to the stiffness of the original rigid attachment. The stiffness was calculated using exoskeleton torque and the corresponding angle of attachment. Torque was calculated based on force applied by the exoskeleton, and the time-varying angle was found using motion capture. The results of these measurements suggest that at the tested frequencies of 0.5, 1, and 2 Hz the stiffness of the exoskeleton-to-shoe interface, which ranged from 8.082 Nm/° to 16.94 Nm/°, is greater than the stiffness of the control, which ranged from 6.143 Nm/° to 6.957 Nm/°. At all tested frequencies, the interface stiffness remained equal to or greater than the natural ankle stiffness during level ground walking. Since the interface stiffness is greater than the natural ankle stiffness, this flexible interface has acceptable stiffness. A flexible, lightweight, and size-variable exoskeleton-to-shoe interface with higher than natural ankle stiffness has the potential to be useful in both future research and eventual commercialization of the exoskeleton. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 40).

Control of a pneumatically actuated joint for wearable supernumerary robotic limbs application

Fri, 01 Jan 2016 00:00:00 GMT

Control of a pneumatically actuated joint for wearable supernumerary robotic limbs application Lo, Roger (Roger D.) Presented is work on the development of the Supernumerary Robotic Limbs project, headed by Federico Parietti in the d'Arbeloff Labs under Prof. Harry Asada. Specifically, this paper focuses on the integration of lightweight, pneumatic systems for prismatic joint actuation, and the various control schemes studied. This joint serves as the leg of the robot, and extends from the hip of the wearer to contact the ground. The design consists of a two-way pneumatic cylinder inside a load bearing carbon fiber sleeve, actuated with a nominally closed 5-3 way solenoid valve, and weighs in at <1kg per actuator. The positional control scheme is closed via tracking from a linear magnetopotentiometer, while the force control scheme utilizes both the positional tracking as well as a load cell at the foot of the leg. System modeling of the actuator dynamics allowed for development of a model based proportional control method. Optimization of the proportional gain and system delay time produced a rise time of 200ms given a step input command for a 250mm stroke. The developed scheme was implemented in the full wearable system to assist a human support weight in crouched positions and standing up from a sitting position. Initial testing has shown the effectiveness of the power, compactness and compliance of pneumatic systems in a wearable robotic device. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 31).

Modeling nonlinear stochastic ocean loads as diffusive stochastic differential equations to derive the dynamic responses of offshore wind turbines

Fri, 01 Jan 2016 00:00:00 GMT

Modeling nonlinear stochastic ocean loads as diffusive stochastic differential equations to derive the dynamic responses of offshore wind turbines Larson, David F. H A procedure is developed for modeling stochastic ocean wave and wind loads as diffusive stochastic differential equations (SDE) in a state space form to derive the response statistics of offshore structures, specifically wind turbines. Often, severe wind and wave systems are highly nonlinear and thus treatment as linear systems is not applicable, leading to computationally expensive Monte Carlo simulations. Using Stratonovich-form diffusive stochastic differential equations, both linear and nonlinear components of the wind thrust can be modeled as 2 state SDE. These processes can be superposed with both the linear and nonlinear (inertial and viscous) wave forces, also modeled as a multi-dimensional state space SDE. Furthermore, upon implementing the ESPRIT algorithm to fit the autocorrelation function of any real sea state spectrum, a simple 2-state space model can be derived to completely describe the wave forces. The resulting compound state-space SDE model forms the input to a multi-dimension state-space Fokker-Planck equation, governing the dynamical response of the wind turbine structure. Its solution yields response, fatigue and failure statistics-information critical to the design of any offshore structure. The resulting Fokker-Planck equation can be solved using existing numerical schemes. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 54).

Mechanical design of an ultrasonic tomographic imaging system

Fri, 01 Jan 2016 00:00:00 GMT

Mechanical design of an ultrasonic tomographic imaging system Mireault, Alfred Norman The paper presents the design and fabrication of a prototype for limb imaging aimed at tackling several of the issues. The design of the a US probe positioning system is intended to augment a system for motion measurement as well as a framework for the integration of motion and US data. The design of the imaging system below represents early steps towards a full-volume imaging technique for use in computer-aided prosthetic socket design. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 42-44).

Visualization and measurement of filmwise and dropwise air gap membrane distillation at varied module inclination angle and gap spacer Orientation

Fri, 01 Jan 2016 00:00:00 GMT

Visualization and measurement of filmwise and dropwise air gap membrane distillation at varied module inclination angle and gap spacer Orientation Morales, Lucien L Improving efficiency is the main target for improving rapidly developing water desalination technologies such as air gap membrane distillation (AGMD). While the system is dominated by heat and mass transfer resistances in the air gap specifically, very little is known about the impact of variations in the air gap, including air gap spacers and module tilting. AGMD experiments were performed by varying inlet temperature, module inclination angle, and gap spacer to identify the effect on the permeate production rate of the system. While AGMD is potentially one of the most efficient types of membrane distillation, experimenting with the tilt angle of the module so as to rotate the membrane and condensation plate off the vertical, provides a method to alter the behavior of the film condensation layer and its associated thermal resistance. In this study, we confirm the previous work of Warsinger et al. (2014) through the added enhancement of visualization of condensation in the air gap by use of a clear and conductive sapphire condensation plate. Additional experiments were run observing the effect of changing the orientation of the mesh spacer holding the air gap in the vertical orientation. Numerical modeling is also conducted to understand and potentially verify the experimental results. As predicted, the results maintain that at near vertical and at non-extreme positive angles (<15° from the vertical), there is no significant difference in the permeate production output of the system due to tilting the module. At declined and extremely inclined tilt angles, the air gap in the module behaves as a "permeate gap", or a flooded system, resulting in the air gap saturated with liquid water. At negative tilt angles past 30°, it was found that condensate tends to fall on the membrane, causing thermal bridging, and as a result, significantly increasing the overall production of permeate condensate. It was also found that the orientation of the mesh spacer holding the air gap apart does not have a significant effect on the permeate production rate. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 36).

Antibody-modified conduits for extracorporeal selective cytokine filtration in sepsis

Fri, 01 Jan 2016 00:00:00 GMT

Antibody-modified conduits for extracorporeal selective cytokine filtration in sepsis Moroi, Morgan K Sepsis kills millions of people worldwide each year and occurs when microorganisms enter the bloodstream of an infected host. The presence of microorganisms in the bloodstream triggers the body to produce many inflammatory proteins, known as cytokines, that cause damage to blood vessels and vital organs. This leads to capillary leak, failing organs, and often death. We have developed a novel approach to modulate the inflammatory response, using antibody-modified conduits (AMCs) to filter harmful cytokines selectively from the circulation and in a time-specific manner. Here, we characterize variables that affect AMC performance to determine optimal AMC conditions for later use downstream. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 37-39).

Physical experimentation and actuated wheel design for granular locomotion using Resistive Force Theory

Fri, 01 Jan 2016 00:00:00 GMT

Physical experimentation and actuated wheel design for granular locomotion using Resistive Force Theory Motley, David Carrington Physical experiments were conducted using 3D printed wheels and a sand testing bed to explore the applications and predictive power of the Resistive Force Theory (RFT), an empirical model based on linear superposition designed to predict the interactive forces between solid bodies and granular media. Four-spoke wheel designs, made of four treads with a hinge halfway down each tread set to a prescribed angle 0, and cylindrical wheels were used to validate a scaling law determined from RFT. The 3D printed wheels were attached to an experimental test rig that consisted of a motor fixed to a carriage free to move horizontally and vertically. Data was gathered through a series of horizontal, vertical, and angular position sensors and a set of force and torque sensors, then processed with a MATLAB script and determined to validate the RFT scaling law. Next, the design of an actuated wheel capable of altering its shaped while in motion was explored. RFT predicts that as motion conditions of the wheel change, a corresponding change in the shape of the wheel would lead to an improvement in the wheel's performance. In order to properly analyze the effect of the change of shape of the wheel, the actuated wheel was designed to first only change shape in the in-plane dimension, and second be sufficiently rigid such that it does not exhibit excessive deformation in the new shape while under load. Several designs were explored, and the final form of the "FrankenWheel" is designed with a series of five flaps that rotate to fixed angles using a system of gears, hinges, and a secondary motor. This version of the "FrankenWheel" has been assembled for testing. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 73).

Design of platform lift for MIT's Skywalker Gamma Project

Fri, 01 Jan 2016 00:00:00 GMT

Design of platform lift for MIT's Skywalker Gamma Project Okaine, Simon A The Skywalker as found in MIT's Newman lab is a device that performs Body Weight Support Treadmill Therapy a form of walking therapy for recovering stroke patients. During clinical trials conducted in the fall of 2014, it became evident that the design of the Skywalker did not fully address how patients would mount and dismount the Skywalker. The current iteration of the design requires the patients to use stairs to mount and dismount the system. Given the gait impairment of the patients using the system it is evident that an alternative must be provided for the stairs in order to make the Skywalker accessible to severe stroke patients. The following thesis explores the idea of using a lead-screw driven platform lift to solve the problem. While the solution developed during the design process is a viable option, the high material cost disqualifies the solution discussed in this thesis as a viable option for implementation in the Skywalker system. The author recommends that alternative solutions such as ramps may provide a more low-cost and effective option for mounting and dismounting the Skywalker. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 92).

Development of inexpensive hands-on mechanics laboratory exercises for the web and around the world

Fri, 01 Jan 2016 00:00:00 GMT

Development of inexpensive hands-on mechanics laboratory exercises for the web and around the world Reed, Rachel C Online education has rapidly expanded in recent years, but offering a true laboratory component to online curricula has been limited by the ability to replicate lab experiments at a low cost. Some online courses offer videos or simulations of lab experiments that can be completed on learner's laptops with little to no physical experimentation. The development and implementation of three hands-on suites of laboratory activities designed for independent learners or for AP physics high school MOOCs on the topics of pendulums, inclined planes, and rubber bands is described, with a focus on the design process of creating low cost labs suitable for a variety of student learners, including single learners, multiple learners, and students with instructor supervision. The goal of these labs is to develop observational, measurement, analysis, and modeling skills that connect to students' experiences in the real world. The aim is to advance experimental insight and develop intuition that connects learners to how physical objects will act in their everyday lives. The experiments have been designed to teach multiple concepts via coordinated sets of hands-on activities, including reducing uncertainty, graphing techniques for clear representation of the functional form of the data, experimental design to minimize systematic errors and comparing different ways of measuring the same physical properties. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 53).

In-process measurement of micro-contact printing

Fri, 01 Jan 2016 00:00:00 GMT

In-process measurement of micro-contact printing Salgado-Bierman, Andrés In micro contact printing, a polymer stamp with sub micron features is use to pattern a substrate. Micro contact printing has many applications including micro machined circuits and miniaturized biological test kits. Success in printing has been achieved in limited batch processing of plate to plate printing. The physics and chemistry of stamp contact and ink transfer has been studied. To make micro contact printing economically viable developments have been made to advance a roll to roll configuration. Roll to roll processing offers the potential of high volume low cost micro manufacturing similar to the high volume achieved by roll to roll processing for traditional lithography. Roll to roll micro contact printers have been built at the lab scale. The process has been demonstrate to have the potential for rapid high volume production. The current limitation is in the quality of the print. Features on the stamp are printed with defects such as breaks or undesired patterning. The source of failure lies with the contact of the stamp; the stamp either breaking contact or collapsing to allow areas outside of the features to make contact. A barrier to better understanding and controlling contact during the printing process has been a lack of in-process measurement. This thesis examines the use of a new optical set-up to monitor stamp contact in-process on a lab level roll to roll micro contact printer. Image based measures of stamp contact quality are presented. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 42-43).

The Global Leadership Program's engineering design challenge as an example of a successful cross-university introduction to engineering and design

Fri, 01 Jan 2016 00:00:00 GMT

The Global Leadership Program's engineering design challenge as an example of a successful cross-university introduction to engineering and design Reiter, Paige Lynette The Global Leadership Program (GLP) is a chance for approximately 35 Singapore University of Technology and Design (SUTD) students to travel to the Massachusetts Institute of Technology (MIT) and participate in a cross-university cultural and educational exchange. The students have the opportunity to collaborate with and learn from MIT's own students and faculty during the program. The highlight of the summer is a nine-week design-build course, referred to as the Engineering Design Challenge, which teaches the fundamentals of engineering design and the necessary fabrication skills to execute those designs. The challenge requires small teams to design and build a single-person electric vehicle (EV). The first two years, the challenge was to make go-karts; since then, the scale has been increased to electric boats. The design challenge is presented as a real-world engineering exercise by intentionally being open-ended and primarily student-driven. It requires the students to practice both their technical skills as well as their interpersonal, professional, and leadership skills. This sort of allencompassing, immersive approach to education is based on principles found within the Project- Based Learning (PBL) and Conceive-Design-Implement-Operate (CDIO) pedagogical frameworks. Though it has only been around since 2013, the program has had a lasting impact on both the students that participated and their peers upon their return to Singapore. Elements of MIT's own student culture were shared with the participants and successfully transplanted back to SUTD at the program's end. This sort of cross-university educational and cultural exchange has exciting implications for expanding the global engineering educational network as the world becomes more and more connected. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 30-31).

Design of a prototype handheld nanoliter pipette

Fri, 01 Jan 2016 00:00:00 GMT

Design of a prototype handheld nanoliter pipette Samsel, Adrian Christopher Handheld pipettes are invaluable to scientists in labs across the globe. Due to high inaccuracies at volumes of less than 1 [mu]L, a nanoliter pipette could truly change the way people research. This experimental nanoliter pipette uses a regulating CAM mechanism and a diaphragm to displace small amounts of fluid. The CAM mechanism has the ability to be adjusted to different steps, each of which controls the amount of working fluid to be displaced in a sealed chamber. In response to this, the diaphragm displaces a smaller volumetric amount of fluid outside the chamber. A deamplification ratio is defined by the ratio of the volume displaced by the diaphragm to the volume displaced by the CAM mechanism. The deamplification ratio is adjustable by changing the setting of the variable CAM mechanism or exchanging different tip assemblies which hold different sized diaphragms. In all, this nanoliter pipette enables measuring and dispensing of very small volumes of liquid, ranging from I nL to 1[mu] L, and can expand the tools of every lab researcher internationally. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 26).

A robotic hand that utilizes ergonomic evaluation as feedback to improve human robot collaboration in soldering applications

Fri, 01 Jan 2016 00:00:00 GMT

A robotic hand that utilizes ergonomic evaluation as feedback to improve human robot collaboration in soldering applications Ort, Moses Teddy People never seem to have enough hands. There are many tools that aim to address this challenge, ranging from the ubiquitous benchtop vise to the "helping hands" commonly used for soldering. However, these tools do not measure up to their human counterparts. They cannot adjust the position or orientation of the workpiece to suit a particular task which can cause workers to maintain unhealthy postures that are detrimental to their long-term health. This thesis addresses this shortcoming with a robotic arm that utilizes a gripper to grasp and hold a workpiece during a soldering task. The robot uses a Microsoft Kinect sensor to continuously analyze the posture of the human worker and calculate a score based on the RULA (Rapid Upper Limb Assessment), an objective measure used in the ergonomics field to evaluate ergonomic working postures. The robot adjusts the workpiece in order to optimize the RULA score using an adaptive simulated annealing algorithm to balance the exploration and exploitation phases of the optimization process. Initial testing indicates that the robot can consistently find positions which improve the RULA ranking by 24.6% of the measured range. This project demonstrates that human robot collaboration can be improved by utilizing sensors to evaluate the needs of a human partner and adjust the robot behavior accordingly. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 49-50).

Modeling abrasive wear of a 3D printer extruder drive mechanism

Fri, 01 Jan 2016 00:00:00 GMT

Modeling abrasive wear of a 3D printer extruder drive mechanism Sandoval, Joseph (Joseph Alexander) Additive manufacturing, more specifically 3D printing using fused filament fabrication (FFF), is a valuable technique; however, little has been done in developing a new mechanism for driving filament through the hot end of the 3D printer. This investigation focuses on a prototype extruder mechanism that utilizes two counter rotating motors to force filament through the nozzle. The plastic passes through the armateurs of the two motors and the oppositely-threaded shafts drive the filament while balancing each others torque. This design provides better protection against jamming of the nozzle. A bench top prototype was able to extrude filament at a rate much greater than traditional mechanisms allow, but the threads on the aluminum shafts wore down with very little use. An abrasive wear model of the extruder shafts was developed in order to determine the theoretical lifetime of the shafts given a certain material hardness. The wear rate of the shafts is proportional to the hardness of the material and the square of the velocity of the extruded filament. Based on this model as well as experiments done with various materials, it is estimated that steel shafts will have a lifetime that is 3 to 10 times longer than aluminum shafts. Still, this lifetime is still far too short for a part meant to be used 24/7. The wear on the threads of the shafts is so severe that no feasible material could survive an adequate lifetime before failure. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 51).

Substitution or revolution? : an empirical analysis of the relationship between ICT and protests

Fri, 01 Jan 2016 00:00:00 GMT

Substitution or revolution? : an empirical analysis of the relationship between ICT and protests Schuman, Joseph P Have cell phones and the Internet created a revolution in the way that protests are organized? Or are they merely a substitution for previous methods of communication? The literature on the topic is divided between the cyberphiles, who argue that information and communication technologies (ICTs) allow individuals to better organize and amplify social movements and the cyberskeptics, who reject the idea that ICT represents a different mechanism of communication and instead argue that protests stem from underlying structural issues. I analyze protests from the Arab Spring and the dissolution of the Soviet Union in order to answer the question of substitution versus revolution. Through my empirical analysis, I find that cell phone subscriptions correlate positively with protest size, meaning countries with more cell phone subscriptions experienced larger protests, ceteris paribus. I did not, however, find the same result with Internet usage. My findings support the "amplification model" - that ICT amplifies existing social movements - but with some added nuance. I argue that the Internet amplifies information about protests to the wrong individuals - namely Internet users abroad who cannot participate in protests - while cell phones are used for domestic communication and thus increase the size of protests. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 26).

Ideation in product design : case study of observed themes and patterns prevalent in the generation of design concepts

Fri, 01 Jan 2016 00:00:00 GMT

Ideation in product design : case study of observed themes and patterns prevalent in the generation of design concepts Senatus, Larissa J This study sought to determine whether there exist identifiable patterns for how ideas are generated using rapid prototyping and sketching tools during a talk-aloud protocol. Three designers' work, as they engaged in a hands-on design activity, were tracked in this experiment. Recordings of their activity were reviewed, and revealed that certain themes are prevalent in the way people design: memories, context, familiarity and innovation. As well, patterns for brainstorming were uncovered: the first identifiable pattern began with the designers drawing from memory, and the other was anchored in the designers' quest to innovate. Finally, the format of the experiment itself seemed to have played a role in the design process. This was observed in the number of designs created by each participant, and by the timing of each breakthrough thought or idea. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 11).

Characterization of the robustness of superhydrophobic surfaces during condensation

Fri, 01 Jan 2016 00:00:00 GMT

Characterization of the robustness of superhydrophobic surfaces during condensation Simpri, Emmanuel E Condensation is a process utilized by about 85% of power plants in their power generation cycles. Superhydrophobic surfaces can potentially improve the heat transfer due to condensation when compared to the untreated surfaces typically used in condensers. This can improve the efficiency of power plants by up to 3%. These surfaces are made by combining nanoscale roughness with chemical hydrophobicity, and can promote the mode of condensation that has the least resistance to heat transfer. However, it is unclear how long these surfaces will last under industrial conditions. This thesis is focused on testing the robustness of the surfaces in multiple experiments and analyzing the data gathered from these experiments, along with theorizing the mechanism behind any surface functionality deterioration that may be seen. Hydrophobic and superhydrophobic surface samples that have been prepared previously were subjected to water immersion and continuous condensation tests. For the water immersion tests, samples were submerged in water under neutral (pH = 7) and basic (pH = 10) conditions at room (~25°C) and elevated (~50°C) temperatures. The continuous condensations tests were run at a steam temperature of 27°C as well as 100°C. To understand the change in surface properties over the duration of the tests, the surface contact angle was chosen as the metric to be measured. The contact angles of water droplets on the samples were taken beforehand and throughout the tests using a micro-goniometer in order to quantify the change in surface functionality. The data gathered from these experiments were processed in Matlab to produce plots of the change in contact angle over the duration of each test. These plots showed significant contact angle decreases for the hydrophobic surfaces but little change in the contact angle for the superhydrophobic surfaces. This suggests that the addition of nanostructures on the surface, and thus the promotion of super- hydrophobicity, inhibits the surface functionality deterioration mechanism that is seen with the hydrophobic surfaces. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 30).

Energy methods for analyzing drag and inertia in cycling kinematics

Fri, 01 Jan 2016 00:00:00 GMT

Energy methods for analyzing drag and inertia in cycling kinematics Steinhardt, Emma Marie A model was developed for measuring the drag and effects of inertia for a cyclist during a race. Professional cyclist data from the Tour de France was acquired for several athletes. The data contained elevation, distance, velocity, and power as a function of time. Rolling resistance, drag, inertial energy, and potential energy were then evaluated. An integral energy equation relating these terms to input power was developed. This is much more stable numerically than differential equations in the power and force equations. This formula gave excellent agreement with the theoretical assumption that inertial effects are negligible. Additionally, the measured drag agreed with wind tunnel results. This work is the first to extract drag data from a cyclist during actual race conditions. In the future, this evaluation of drag variation coupled with energy equations could lead to optimizing cycling strategy. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 53-54).

Impact of rim weight and torque in discus performance

Fri, 01 Jan 2016 00:00:00 GMT

Impact of rim weight and torque in discus performance Stuopis, Isabella The discus throw is one of the oldest sporting events in track and field. Despite this, there has not been very much dynamic analysis on the throw and the ability of an athlete to apply the proper forces and torques to the discus. This paper looks at measuring the ability of the athlete to create spin on the discus by applying torque in the throwing process. The results from the experiment described in this paper were inconclusive, though there was a general trend that as the normal force into the discus increases, the angular velocity increased. However, this was minimally correlated from the data supplied. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 14).

Simplifying tea steeping : design innovation driven by user needs

Fri, 01 Jan 2016 00:00:00 GMT

Simplifying tea steeping : design innovation driven by user needs Tatar, Katherine Ann An affordable appliance was designed to make steeping a "perfect" cup of loose leaf tea easy and less labor intensive for the user. A survey of 235 people, primarily millennials between the ages of 18-27, was conducted to determine key user needs to be addressed in the design of the tea steeping device. Primary concerns identified were cleanability, time it takes to brew, and making the device compatible with travel mugs so users can drink their tea on the go. These key user needs were addressed through system architecture, form factor, and materials selection. A method of steeping a concentrate to minimize brew chamber size was developed. The automated single-serve device proposed brews tea at the required temperature and time to allow users to enjoy the best flavor out of their tea with just one step. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 31-33).

Dynamic exoskeleton : mechanical design of a human exoskeleton to enhance maximum dynamic performance

Fri, 01 Jan 2016 00:00:00 GMT

Dynamic exoskeleton : mechanical design of a human exoskeleton to enhance maximum dynamic performance Tims, Jacob (Jacob F.) An exoskeleton was designed with the primary goal of enhancing the maximum dynamic capability of a human, thus allowing the user to run faster, jump higher, or traverse challenging terrain. This paper presents the mechanical design of an alpha prototype with a focus on increasing the maximum vertical jump height of a human. High torque motors were constrained to the body with two degrees of freedom using carbon fiber, aluminum, and other lightweight materials. The exoskeleton actuates the hip joint by comfortably providing force to three points on the body. Human testing showed a maximum increase in jump height of 13%. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 12).

Documentation and analysis of avocado oil extraction technologies in Leguruki, Tanzania

Fri, 01 Jan 2016 00:00:00 GMT

Documentation and analysis of avocado oil extraction technologies in Leguruki, Tanzania Wang, Lesley A team of MIT students and researchers as well as a local team in Leguruki, Tanzania has been working on extracting oil from excess supplies of avocados since 2014 with the goal of adapting oil extraction methods to small-scale farmers. Through this process of extracting oil, the team has explored several iterations of avocado dryers, presses, and centrifuges. Analyzing this machinery has given a broader picture of the commonalities and requirements of the designs. A set of evaluation criteria can be extracted from this analysis. Having these guidelines in place for future designs for oil extraction will streamline and aid the process, facilitating the small-scale production of avocado oil, and eventually augmenting the incomes of small-scale farmers. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 56-57).

The identification and validation of case hardening for extending charcoal briquette extruder lifespan

Fri, 01 Jan 2016 00:00:00 GMT

The identification and validation of case hardening for extending charcoal briquette extruder lifespan Wang, Lindsey (Lindsey M.) Appropriate Energy Saving Technologies Ltd. (AEST) located in Soroti, Uganda aims to reduce deforestation and indoor air pollution through their sustainable charcoal briquettes. However, the charcoal mixture causes extreme wear in the briquette extruding machines, restricting the business's ability to scale up. Case hardening was identified as a potential solution to increase the wear resistance of the extruders by diffusing carbon into key components of the machine such as the screw. Several steps were taken at MIT D-Lab to validate the case hardening strategy including measuring the carbon content of steel samples from AEST's machines; designing a furnace from materials widely available in Soroti that could achieve the temperature necessary for case hardening; and evaluating different types of quenching liquids. Once the process had been validated, D-Lab researchers and AEST employees implemented the procedure at AEST's briquette production site, building a brick furnace and case hardening three screws. AEST has since reported that the case hardened screw produces twice as many briquettes during its lifespan as the untreated screw does. AEST is now looking to case harden other machines at their workshop to increase overall briquette output. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 43).

Study of human motor control and task performance with circular constraints

Fri, 01 Jan 2016 00:00:00 GMT

Study of human motor control and task performance with circular constraints Wilcox, Brian (Brian P.) This thesis aims to investigate human motor control strategies. Curved constraints offer a unique opportunity to exploit forces of contact. A circular crank experiment using the MIT MANUS robot was designed in order to test how well subjects can follow a set of simple instructions to rotate the crank at various constant speeds. 10 subjects volunteered to participate in this experiment. Velocity, force, and EMG data were collected during four tasks: turning the crank at the subject's preferred or comfortable speed, turning the crank at a constant preferred speed, turning the crank at a constant preferred speed with a visual feedback display, and rotating the crank at three instructed speeds (slow, medium, and fast) with visual feedback. The coefficient of variation (CV) of the velocity for each trial was computed as a measure of performance. Statistical analysis showed that speed significantly affected CV but the direction of turning the crank, clockwise or counterclockwise, did not. The observation that CV increased as speed decreased, despite visual feedback, confirms previous studies showing that human motor control is more imprecise at slower speeds. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 42).

Exploring methods to enable responsible alcohol consumption in social environments

Fri, 01 Jan 2016 00:00:00 GMT

Exploring methods to enable responsible alcohol consumption in social environments Williams, Benjamin Craig With the recent rise in alcohol related incidents and deaths in the United States we have seen new technologies and tools to try to reduce the number of these occurrences. Apps such as Uber are only a click away from being able to pick up an intoxicated person at a party and there is research being done at Washington University on an application to communicate with your friends that you are too drunk while at a party based on Transdermal Alcohol Content (TAC). This thesis presents an idea and initial feasibility experiments for an affordable one-night-use wristband that would be able to change colors based on your TAC and encourage wearers to be aware of how much alcohol they have actually consumed throughout the night, with the goal of reducing the number of incidents and deaths. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 19).

Design and prototype of a lamp build kit for STEM education

Fri, 01 Jan 2016 00:00:00 GMT

Design and prototype of a lamp build kit for STEM education Wright, Lauren L This thesis describes a case study of an early phase product design process. Company J is a startup toy company creating toys that encourage STEM education and participation. One product in their anticipated lineup is a lamp construction kit. Through the process of assembling users learn about basic engineering and electronics concepts. This project concerns redesigning an early-stage prototype to further the product development and move it towards mass-manufacturability. The design process began with different levels of ideation and concept selection. Then, models were made both virtually and physically to attain user feedback. Once the final design was selected, more advanced prototyping methods were used to create a next-generation prototype. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.

Getting to gender parity in the Mechanical Engineering Department at MIT

Fri, 01 Jan 2016 00:00:00 GMT

Getting to gender parity in the Mechanical Engineering Department at MIT Xu, Kathleen L Consistently ranked as home to one of the world's top engineering programs, the Massachusetts Institute of Technology (MIT) is often seen as a model for its undergraduate education programs and research output. But MIT leads in another important way: the Institute also boasts one of the most gender-balanced STEM-oriented undergraduate student bodies in the world. The purpose of the study was to help illuminate how the Mechanical Engineering Department in particular has reached near parity in its female undergraduate population: in 2015, females composed 46.4% of declared mechanical engineering majors. This study's approach was twofold: first, the gender enrollments in the largest mechanical engineering elective classes over the past 15 years were analyzed to determine differences, if any, in the subfields that female and male students choose to devote further study to. Second, a cross section of mechanical engineering faculty and staff were interviewed to evaluate how the department has changed over a similar timespan to make the place a much more welcoming place for women now. The data analysis revealed that a larger fraction of undergraduate males in the department take the robotics and the controls classes than females do, but an increasing fraction of females in the department have taken the robotics class over time. The interview analysis presented several factors that contributed to the gender parity in the department over time, including changed hiring practices, role modeling, and careful attention to classroom dynamics. Ultimately, it is hoped that the findings in this thesis can help both the department and other institutions continue their paths to greater gender balance in their engineering programs. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 90-95).

Automatic detection of periodic sources in the K2 data sets

Fri, 01 Jan 2016 00:00:00 GMT

Automatic detection of periodic sources in the K2 data sets Molnar, Momchil Emil We present an automated algorithm for the detection of periodic sources in the K2 data sets. Fast discreet Fourier transformations are used to compute the Fourier spectra of the targets and two different detection algorithms for identifying significant signals are used. The first technique searches through the DFT to identify peaks that are significantly above the background noise level, and which have at least one higher harmonic of the fundamental frequency. We show this approach to be relatively inefficient for detecting weaker sources with narrow features, such as transiting exoplanets. The second algorithm that we apply uses a summation of the DFT harmonics, which relies on the fact that typical planetary transits and binary eclipses have numerous harmonics in their Fourier spectra. In this method we sum the harmonics of the fundamental frequency, which increases the signal-to-noise ratio and substantially increases the detection efficiency of the algorithm. This latter technique yields a smaller number of false positives while having higher detection rates than the first approach. A discussion of the noise level and detection threshold is presented, with a derivation of the threshold for the algorithm based on the noise properties in the K2 data. Furthermore, a discussion of the performance of both algorithms is presented. We then apply this automated search algorithm to the sixth and seventh fields of the K2 mission. In all these fields contained some 45,000 stars that were monitored for nearly three months each. The automated search yielded about 2000 interesting periodic targets. We conclude with a short discussion of the more interesting objects detected in the C7 data release by the K2 team. Finally, we present a catalog of many of the periodic sources that we have detected using these algorithms in the Appendix. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references.

Implementation of side-fringe locking in an SHG cavity

Fri, 01 Jan 2016 00:00:00 GMT

Implementation of side-fringe locking in an SHG cavity Moore, Sam, S.B. Massachusetts Institute of Technology An alternative method for locking a second-harmonic generation (SHG) cavity on resonance is described and implemented. The usual method, Pound-Drever-Hall locking, is prone to long-term power fluctuations from power variations in the incident laser. When using the second harmonic field for squeezing, these power fluctuations need to be stabilized with an additional control loop (usually a Mach-Zender interferometer). The alternative method, side-fringe locking, involves a simple DC offset on the second-harmonic signal at the desired power to generate the error signal. This thesis demonstrates the insensitivity of side-fringe locking to such long-term power fluctuations and that the noise spectrum is comparable to PDH locking-explained largely due to PZT noise length fluctuations off-resonance.. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Pages 36-39 are missing. Cataloged from PDF version of thesis.; Includes bibliographical references (pages 40-41).

Effect of magnetic seed fields on Lyman Alpha emission from distant quasars

Fri, 01 Jan 2016 00:00:00 GMT

Effect of magnetic seed fields on Lyman Alpha emission from distant quasars Narayanan, Sruthi Annapoorny There are indications that weak magnetic fields originating in the early Universe and magnified via magnetohydrodynamic (MHD) processes could cause perturbations in the thermodynamic state of the gas in the intergalactic medium which affect the Lyman-Alpha spectrum we observe. In this work we investigate to what extent the properties of the Lyman-Alpha forest are sensitive to the presence of large-scale cosmological magnetic fields as a function of the seed field intensity. To do so, we develop and use a series of numerical tools to analyze previously constructed cosmological MHD simulations that include state-of-the-art implementation of the relevant physical processes for galaxy formation. The inclusion of these physical mechanisms is crucial to get the level of magnetic field amplification currently observed in the structures that populate our Universe. With these tools we isolate characteristics, namely the Flux Probability Density Function and the Power Spectrum, of the Lyman-Alpha forest that are sensitive to the magnetic field strength. We then examine the implications of our results. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 55-57).

Neutron backgrounds in the Ricochet experiment

Fri, 01 Jan 2016 00:00:00 GMT

Neutron backgrounds in the Ricochet experiment Newman, Elise (Elise S.) This paper explores the impact of neutron backgrounds on the Ricochet experiment. The purpose of the Ricochet experiment is to determine the existence of sterile neutrinos via coherent neutrino-nucleus scattering. Coherent neutrino-nucleus scattering is an ideal detection method because it is a neutral current process. All active neutrino flavors will therefore be detected uniformly (no non-active, or sterile neutrinos will be detected because they do not couple to the Z boson). By varying the distance between the detector and the neutrino source, we consider deficits in neutrino flux to be evidence of oscillation to a fourth, non-active neutrino. Neutron backgrounds could interfere with neutrino detection. We therefore calibrate and employ Neutral Current Detectors (NCD's) for the purpose of neutron detection to measure the expected neutron spectrum incident on the detector. We furthermore design a Monte Carlo simulation to model the expected neutron capture rate of the neutrino detector in this setup. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 59).

Preheating in multifield inflation

Fri, 01 Jan 2016 00:00:00 GMT

Preheating in multifield inflation Prabhu, Anirudh, S.B. Massachusetts Institute of Technology The theory of cosmic inflation was proposed to address problems with Standard Big Bang cosmology. The theory suggests the existence of an epoch during which the universe underwent an exponential expansion, followed by an epoch of slower expansion. Realistic models of high-energy physics require multiple scalar fields. Renormalization of these fields in curved space-time requires these fields to be nonminimally coupled to the space-time Ricci scalar. These couplings induce a nontrivial field-space manifold when we move from the Jordan frame to the Einstein frame. In the Einstein frame, the potential becomes asymptotically flat, leading to ridges and valleys in field-space. The existence of these ridges and valleys results in a strong single-field attractor behavior of the fields. We study preheating in multifield models of inflation with nonminimal couplings. In this phase, we find an efficient transfer of energy from the oscillating background fields to the coupled fluctuations. We identify features of preheating that are not present in the minimally coupled case. In particular, we observe how the Fourier structure of the background field oscillations changes as the value of the dimensionless non-minimal coupling, [zeta]1 changes. We also observe how the resonance structure of perturbations changes as we tune [zeta]1. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 81-83).

Super-quantum and quantum enhancements of two-sender channels

Fri, 01 Jan 2016 00:00:00 GMT

Super-quantum and quantum enhancements of two-sender channels Quek, Yihui This thesis studies the consequences of 'super-quantum non-local correlations', which are hypothetical violations of Bell/CHSH inequalities that are stronger - more nonlocal - than quantum mechanics allows, yet weak enough to respect special relativity in prohibiting faster-than-light communication. Understanding the power of such correlations will yield insight into the non-locality of quantum mechanics. Whereas previous studies of super-quantum correlations have demonstrated enhancements in cryptography and computation of distributed functions, this work opens up a new direction of research by showing that they can also enhance the capacity of classical communication over a noisy channel. Our results exhibit a trifecta of proof-of-concept channels: first, we show an interference channel between two sender-receiver pairs where the senders are not allowed to communicate, for which a shared super-quantum bit allows perfect classical communication. This feat is not achievable with the best classical (senders share no resources) or quantum-assisted (senders share entanglement) strategies. We next show two examples that are conjectured to demonstrate the following capacity separations: an interference channel that strictly separates super-quantum from quantum-assisted strategies, and quantum-assisted from classical strategies; and, lastly, a multiple-access channel that strictly separates super-quantum- assisted strategies from classical ones. At the heart of some of these examples is a novel connection between multi-sender channels and multi-player XOR and pseudo-telepathy games. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 67-70).

Engineering the couplings to the continuum : controlling the fundamental properties of radiation and enabling forbidden light-matter

Fri, 01 Jan 2016 00:00:00 GMT

Engineering the couplings to the continuum : controlling the fundamental properties of radiation and enabling forbidden light-matter Rivera, Nicholas (Nicholas H.) In this thesis, I consider the general question: what new dynamics can be realized by engineering the coupling between a discrete state and a continuum of states? In the first part of the thesis, we choose bound states in the continuum (BICs) as our starting point for answering this question. We construct a large class of BICs associated with separable Hamiltonians and show that by designing special perturbations of these systems, the dimensionality and propagation direction of waves can be controlled. We present potential realizations of this physics in potentials for ultracold atoms, optically induced potentials for photons, and lattice systems.Such resonances with easily reconfigurable radiation allows for applications such as the storage and release of waves at a controllable rate and direction and systems that switch between different dimensions of confinement. In the second part of the thesis, we look at the same question in a different physical setting: the coupling of electrons to the electromagnetic fields of polaritons such as plasmon and phonon-polaritons. We consider the potential for 2D materials such as graphene, thin films of SiC, and hBN to enable atomic and molecular transitions that have, to this date been either very difficult to observe, or have not yet been observed. Examples of such transitions include high-order multipolar transitions (as high as E5), multi-photon spontaneous emission, and intercombination processes such as spin-flip phosphorescence transitions. We find that plasmon polaritons in graphene can speed up spin-flip phosphorescence process by 7 orders of magnitude, that they can speed up two-photon spontaneous emission processes by 15 orders of magnitude, and that they can speed up multipolar transitions by over 20 orders of magnitude. This brings the lifetimes of all of these transitions to the nanosecond scale, comparable with the speed of the single-plasmon dipole transitions which have traditionally been thought to be the only transitions worth considering in most circumstances. The potential applications of this work include: spectroscopy for inferring electronic transitions which cannot be determined with photons, sensors based on forbidden transitions, organic-light sources arising from fast singlet-triplet transitions, fast entangled light generation, and fast generation of broadband light with tunable width in the visible or IR. From there, we ask: is it possible to engineer couplings between an electron and its radiative continuum such that it prefers to spontaneously emit via a conventionally forbidden transition? We find an affirmative answer. In particular, we show that in these systems, it is possible to have an electron prefer to change its orbital angular momentum by more than one. Processes that normally take years to happen are typically considered negligible become dominant processes which happen on the scale of nanoseconds. Going beyond processes at first order, we find that it is also possible to have an electron prefer to decay by the emission of two near-field photons, even when it is possible for the electron to decay via the emission of a far-field photon. In the process of showing these results, we arrive at a general result connecting the enhancement of N-photon emission to the Purcell factor, which has been of fundamental importance in quantum nanophotonics. Our results have direct implications for the design of fundamentally new types of emitters in the mid and far IR: ones which prefer to change their angular momentum by large amounts and also ones that prefer to emit a relatively broad spectrum of entangled photons. Our results may allow for the possibility of ushering in new classes of quantum emitters with tunable multi polarity and/or tunable emission spectra, in addition to new materials for broad-band absorption and emission, new capabilities for IR spectroscopy, sensing platforms, and many other applications. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 121-130).

Chemical abundance analysis of HE 2324-0215, an r-process-enhanced metal-poor star

Fri, 01 Jan 2016 00:00:00 GMT

Chemical abundance analysis of HE 2324-0215, an r-process-enhanced metal-poor star Thanathibodee, Thanawuth We report the abundance analysis of the metal-poor halo star HE 2324-0215 for 22 neutron-capture elements and 14 light elements with Z < 30. The stellar parameters are [Fe/H] = -3.05 ± 0.17, Teff = 4477 K, Vt = 2.70 kms-1 , and log(g) = 0.70, indicating that HE 2324-0215 is a red giant star. The [Eu/Fe] = 0.73 and [Ba/Eu] = -0.68 suggests that this is an r-I star. Since thorium is detectable in this star, we derived the age of the star by the means of radioactive decay, resulting in the age of 13.0 ± 1.0 Gyr. The age and the metallicity of the star suggest that HE 2324-0215 formed in a dwarf galaxy which was later accreted and became part of the Milky Way. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 35-36).

Tailoring light with photonic crystal slabs : from directional emission to topological half charges

Fri, 01 Jan 2016 00:00:00 GMT

Tailoring light with photonic crystal slabs : from directional emission to topological half charges Zhou, Hengyun, S.B. Massachusetts Institute of Technology Photonic crystal slabs are a versatile and important platform for molding the flow of light. In this thesis, we consider ways to control the emission of light from photonic crystal slab structures, specifically focusing on directional, asymmetric emission, and on emitting light with interesting topological features. First, we develop a general coupled-mode theory formalism to derive bounds on the asymmetric decay rates to top and bottom of a photonic crystal slab, for a resonance with arbitrary in-plane wavevector. We then employ this formalism to inversion symmetric structures, and show through numerical simulations that asymmetries of top-down decay rates exceeding 104 can be achieved by tuning the resonance frequency to coincide with the perfectly transmitting Fabry-Perot frequency. The emission direction can also be rapidly switched from top to bottom by tuning the wavevector or frequency. We then consider the generation of Mobius strips of light polarization, i.e. vector beams with half-integer polarization winding, from photonic crystal slabs. We show that a quadratic degeneracy formed by symmetry considerations can be split into a pair of Dirac points, which can be further split into four exceptional points. Through calculations of an analytical two-band model and numerical simulations of two-dimensional photonic crystals and photonic crystal slabs, we demonstrate the existence of isofrequency contours encircling two exceptional points, and show the half-integer polarization winding along these isofrequency contours. We further propose a realistic photonic crystal slab structure and experimental setup to verify the existence of such Mobius strips of light polarization. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 75-80).

Development of a beamline system for characterization of X-ray and neutron optics

Fri, 01 Jan 2016 00:00:00 GMT

Development of a beamline system for characterization of X-ray and neutron optics Ames, Andrew O. (Andrew Owen) In this thesis, I present a beamline system designed and built at the Harvard-Smithsonian Center for Astrophysics (CfA) to measure the reflectivity and resolution of small diameter multilayer coated Wolter optics. These optics, used for imaging of x-rays and neutrons, have numerous applications in areas such as medicine, fusion research and planetary science. The beamline consists of a divergent x-ray source, an energy sensitive detector, and a set of precise, computer controlled motorized stages for alignment. A dedicated software package was developed to interface with the detector and stages using the Python programming language. The beamline was used to measure the reflectivity and spatial resolution of two x-ray optics recently fabricated at the CfA. These results are presented and compared with theoretical models for reflectivity from a multilayer surface. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 69-71).

Mass ratios in stellar triple systems that admit horseshoe orbits

Fri, 01 Jan 2016 00:00:00 GMT

Mass ratios in stellar triple systems that admit horseshoe orbits Balaji, Bhaskaran We examine possible configurations of stellar triple systems that give rise to "horseshoe orbits" in the smallest body. Several configurations are tested according to the initial parameters of mass for each of three bodies and position and velocity for the smallest body. The masses are arranged hierarchically, so as to mimic systems like Sun- Jupiter-Trojan. For a mass ratio of 1:10-4:10-8 known to produce horseshoe orbits, a grid search was performed on position and velocity of the small body to determine admissible initial conditions. Then, a strongly suitable initial condition was chosen to run another grid search on masses of the middle and small bodies. Choosing a criterion for stability of horseshoe orbits-given that they all decay-produced a timescale for stability, with (numerical) functional dependences on the middle and smaller masses. Fitting a power law for each resulted in exponents of k1, = -1.006 ± 0.006 and k2 = -1.047 ± 0.005 respectively, which we compare to related results from Murray & Dermott (1981a). Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 47).

Orbital decay of hot Jupiters : coefficients of nonlinear tidal coupling as a function of the stellar host type

Fri, 01 Jan 2016 00:00:00 GMT

Orbital decay of hot Jupiters : coefficients of nonlinear tidal coupling as a function of the stellar host type Belland, Brent (Brent R.) Hot Jupiters raise strong tides in their host stars due to their large masses (around a Jupiter mass) and tight orbits (orbital periods P

Transport in chaotic magnetic fields

Fri, 01 Jan 2016 00:00:00 GMT

Transport in chaotic magnetic fields Holguin, Francisco, Jr Many astrophysical environments are thought to contain force-free magnetic fields. The sine field is an example of a force-free, helical magnetic field, whose field lines are chaotic over the entire space. In this thesis, we examine the transport properties of magnetic field lines and particles in three related systems: the sine field, the sine field superimposed with a constant background field, and a time varying sine field. We also compare results with the Arnold-Beltrami-Childress (ABC) field. In the time-independent sine field, we find that particles exhibit chaotic motion, shown by a non-zero distribution of Lyapunov exponents (LE). While for low energies the asymtotic LE do not depend on initial particle position or angle with respect to the local magnetic field line, these parameters are important for higher energies. On larger time scales, we find that an ensemble of particles undergoes close to normal diffusion for low energies and superdiffusion for high energies. This contrasts with the superdiffusion found at low energies with the ABC field. Additionally, we find that adding a constant magnetic introduces a saturation time scale in the cross field diffusion. The saturatino can be both temporary or more long term. We find that the low energy particle motion is ballistic. In contrast, for higher energies we find widely varying behavior, ranging from superdiffusion to normal diffusion. At the highest energies though, the behavior becomes uniformly superdiffusive. Futhermore, we introduce a simple sinusoidal time variation into the sine field. We find that in the pure sine field, the particle energy experiences subdiffusion throughout all the time scales. With the constant field added, there is only energization at long timescales, and although not completely conclusive, it looks to eventually undergo normal diffusion in energy. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 51-52).

Detection of core-collapse supernovae through joint analysis of LIGO gravitational wave and KamLAND neutrino data

Fri, 01 Jan 2016 00:00:00 GMT

Detection of core-collapse supernovae through joint analysis of LIGO gravitational wave and KamLAND neutrino data Krupczak, Emmett E. E Introduction: Core collapse supernova are one of the most intriguing astrophysical phenomena. The dying stage of a supergiant star, they occur when the star collapses into a protoneutron star, causing a shock wave and a gamma ray burst. High energy neutrinos are released in this process and offer the possibility of detecting these elusive cataclysms. The number of neutrinos emitted is large but at best only a few will be detected. With a multi-messenger search, we can combine the neutrino signal with another clue to the presence of a supernova: gravitational waves. During the proto-neutron star stage, a fast-rotating star can produce gravitational waves via its asymmetric and rapidly shifting mass. By combining the signals from neutrinos and gravitational waves, we can attempt to detect supernova signals that are too faint to detect alone. Joint searches have already been attempted by several neutrino experiments with high-energy thresholds, including ANTARES and IceCube. This thesis explores the possibility of a joint search with a new set of neutrino data. KamLAND (Kamioka Liquid scintillator Anti-Neutrino Detector) is a large particle detector located in Kamioka, Japan. KamLAND is well-shielded, with an low (~ 1 MeV) energy threshold and has more than ten years of data to explore, making it a good candidate for a joint search. A recent search of KamLAND's data for clustered events indicative of supernova found no clear clusters. A new search is needed to identify single-neutrino events that may have originated in supernovae. A joint search will help KamLAND more carefully examine the possible sources of its single-neutrino events. The gravitational wave data comes from LIGO (Laser Interferometer Gravitational wave Observatory). Located in Hanford, WA and Livingston, LA, LIGO consists of two four-kilometer interferometer arms. Analysis of LIGO data from 2005 to 2010 did not produce any clear gravitational wave events, leading to a need for a more sensitive search. A multimessenger search in conjunction with KamLAND provides this opportunity. We can examine both KamLAND and LIGO's data in order to search for possible supernova signals observed by both experiments. Because a joint data-sharing agreement has not been reached between KamLAND and LIGO, this thesis looks at the potential of a joint analysis and the opportunity for such a study to produce promising results. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 45-47).

Global simulations of heat-flux-driven buoyancy and magnetothermal instabilities, and their astrophysical implications

Fri, 01 Jan 2016 00:00:00 GMT

Global simulations of heat-flux-driven buoyancy and magnetothermal instabilities, and their astrophysical implications Kulchoakrungsun, Ekapob In this thesis, we investigate the convective instabilities induced by anisotropic conduction in a rapidly conducting plasma. We simulate the magneto-thermal instability (MTI), and the heat-flux-driven buoyancy instability (HBI) in two- and three- dimensional, global hydrodynamic simulations performed by the AREPO code, and verify the results of previous works. Our results have important astrophysical implications, such as the conductive heat transport in galaxy clusters. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (page 36).

Novel data-processing techniques for signal extraction in Project 8

Fri, 01 Jan 2016 00:00:00 GMT

Novel data-processing techniques for signal extraction in Project 8 Kunicki, Theodora C Project 8 presents a new modality of electron spectroscopy with the potential to exceed the resolution of the most precise electron spectrometers in operation today, potentially at much lower cost. Project 8, being a novel method, has different computational demands from existing experiments. This thesis explores the use of the Hough Transform as a tool in data processing in Project 8 and discusses its utility and function generally. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 49-50).

Effects of electrode surface roughness on motional heating of trapped ions

Fri, 01 Jan 2016 00:00:00 GMT

Effects of electrode surface roughness on motional heating of trapped ions Lin, Kuan-Yu, S.B. Massachusetts Institute of Technology Electric field noise is a major source of motional heating in trapped ion quantum computation. While the influence of trap electrode geometries on electric field noise has been studied in patch potential and surface adsorbate models, only smooth surfaces are accounted for by current theory. The effects of roughness, a ubiquitous feature of surface electrodes, are poorly understood. We investigate its impact on electric field noise by deriving a rough-surface Green's function and evaluating its effects on adsorbate-surface binding energies. At cryogenic temperatures, heating rate contributions from adsorbates are predicted to exhibit an exponential sensitivity to local surface curvature, leading to either a large net enhancement or suppression over smooth surfaces. For typical experimental parameters, orders-of-magnitude variations in total heating rates can occur depending on the spatial distribution of absorbates. Through careful engineering of electrode surface profiles, our results suggests that heating rates can be tuned over orders of magnitudes. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 49-51).

Using 2D vortex plasmons/phonon polaritons to control electronic selection rules

Fri, 01 Jan 2016 00:00:00 GMT

Using 2D vortex plasmons/phonon polaritons to control electronic selection rules Leal Machado, Francisco The discovery of orbital angular momentum (OAM) sustaining modes established a new degree of freedom by which to control not only the flow of light but also its interaction with matter. However, OAM sustaining modes have yet to be used to control the quantum dynamics of an electron in an atom or molecule due to the large length scale discrepancy between the wavelength of light and the size of the electron's orbital. In this work, we analyze the interaction between OAM carrying polariton vortex modes (for plasmon and phonon polaritons) and a hydrogen atom, and show that these modes can be used to engineer new selection rules in electronic transitions. Moreover, we show that these selection rules are robust to the displacement of the electronic system away from the vortex center. Perhaps more surprisingly, we find how displacement can be used favourably to tune which absorption process is dominant. Our findings are best suited to vortex modes that can be created in graphene, monolayer conductors, hBN, thin polar dielectrics, and many other polariton-sustaining thin materials. Another platform for observing these effects could be quantum dots interfaced with surface plasmons in-conventional metals. Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2016.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 69-73).

Let there be Luxo : a jumping lamp sheds light on heavy legged locomotion

Wed, 01 Jan 1997 00:00:00 GMT

Let there be Luxo : a jumping lamp sheds light on heavy legged locomotion Paluska, Daniel Joseph, 1974- Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1997.; Includes bibliographical references (leaf 35).

Comparison of Kane's dynamical equations to traditional dynamical techniques

Tue, 01 Jan 1991 00:00:00 GMT

Comparison of Kane's dynamical equations to traditional dynamical techniques Root, Stephen Thomassy Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1991.; Includes bibliographical references (leaf 46).

Low cost, high performance actuators for dynamic robots

Fri, 01 Jan 2016 00:00:00 GMT

Low cost, high performance actuators for dynamic robots Katz, Benjamin G The recent growth of the remote control airplane and drone market has created great availability of extremely cheap, yet very power and torque dense electric motors. However, these motors have for the most part been neglected by the robotics community. This thesis documents the development of a hardware, firmware, and controls platform for using these motors in robotics applications - specifically for running robots. A sampling of these motors were characterized, and appropriate position sensing, power electronics and field-oriented motor control systems for torque, position, and impedance control of the motors was developed. Additionally, a module which combines motor, electronics, and single-stage planetary gearset was designed and fabricated. For demonstration, a pair of these motor-controller- gearbox modules were incorporated in a 2-degree- of-freedom leg capable of jumping and controlling its joint impedances. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (page 47).

Optimizing cycling power

Fri, 01 Jan 2016 00:00:00 GMT

Optimizing cycling power Springer, Alexander D In this study we determine a viable bioenergetic model for power allocation during a cycling race. Various models have been proposed to address power allocation in races with two models rising above others: the Morton-Margaria Three Tank model and the Skiba Energy Balance model. The energy balance model was implemented in MATLAB and compared against the gold standard implementation in Golden Cheetah to model the depletion of an athlete's energy over the course a ride. The implementation of the model was successful as verified by ride data from a cyclist in the 2014 Tour de France. Additionally, the model was further tested with sample power profiles in order to understand the depletion of energy over the course of a ride. Two key findings emerged from the investigation. First, we require a better account of exhaustion in the energy balance model which can be achieved by weighting the time spent below critical power over the time spent above critical power. This is because a cyclist becomes more exhausted by efforts at higher power outputs compared to the recovery at an effort below critical power. Second, energy balance models should use a variable time constant as rides and races have highly variable recovery periods below critical power which affects the ability of an athlete to reconstitute their energy. Use of a variable time constant could address the weighting of efforts below critical power identified in the first finding as well. Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Cataloged from student-submitted PDF version of thesis.; Includes bibliographical references (page 29).