https://hdl.handle.net/1721.1/91572 2026-04-05T20:33:43Z 2026-04-05T20:33:43Z Wescoat, James Fletcher, Sarah Marie Novellino, Marianna https://hdl.handle.net/1721.1/106328 2022-10-01T05:28:19Z 2016-02-01T00:00:00Z

National rural drinking water monitoring: progress and challenges with India's IMIS database Wescoat, James; Fletcher, Sarah Marie; Novellino, Marianna National drinking water programs seek to address monitoring challenges that include self-reporting, data sampling, data consistency and quality, and sufficient frequency to assess the sustainability of water systems. India stands out for its comprehensive rural water database known as Integrated Management Information System (IMIS), which conducts annual monitoring of drinking water coverage, water quality, and related program components from the habitation level to the district, state, and national levels. The objective of this paper is to evaluate IMIS as a national rural water supply monitoring platform. This is important because IMIS is the official government database for rural water in India, and it is used to allocate resources and track the results of government policies. After putting India's IMIS database in an international context, the paper describes its detailed structure and content. It then illustrates the geographic patterns of water supply and water quality that IMIS can present, as well as data analysis issues that were identified. In particular, the fifth section of the paper identifies limitations on the use of state-level data for explanatory regression analysis. These limitations lead to recommendations for improving data analysis to support national rural water monitoring and evaluation, along with strategic approaches to data quality assurance, data access, and database functionality.

2016-02-01T00:00:00Z Greenlee, Alison S. Murray, Timothy Lesniewski, Victor Jeunnette, Mark Winter, Amos G. https://hdl.handle.net/1721.1/99523 2024-03-23T02:15:53Z 2014-08-01T00:00:00Z

Delivering a low-cost, reliable drip irrigation filtration system for micro-irrigation in developing countries Greenlee, Alison S.; Murray, Timothy; Lesniewski, Victor; Jeunnette, Mark; Winter, Amos G. The cylindrical filters presently used in drip irrigation systems frequently clog, increasing pressure loss and lowering the flow rate through the filters. This work investigates alternative filtration strategies that increase the reliability of, and are compatible with, existing systems. To test different filtration strategies, a drip irrigation test setup was built to measure the pressure loss across different filters as particles accumulated. These experiments found that pleated cartridge filters, with high effective surface area, incurred the lowest pressure losses. More significantly, it was observed during these tests that the filtered out particles settled to the bottom of the filter housing when flow through the filter ceased. This inspired the redesign of the filter housing such that the housing extended far below the filter, providing a catch basin away from the filter for the particles to settle. Fixing the filter independently of the bottom casing significantly improves the overall performance of the filtration system and can be inexpensively manufactured via blow molding. This paper experimentally demonstrates that the cartridge filter inside the redesigned housing can filter out over 2 kg of sand while maintaining less than a .03 bar pressure drop across the filter at a flow rate of 25 l/s.

2014-08-01T00:00:00Z Olesnavage, Kathryn Winter, Amos https://hdl.handle.net/1721.1/98256 2022-09-28T17:41:36Z 2014-08-01T00:00:00Z

Analysis of Rollover Shape and Energy Storage and Return in Cantilever Beam-Type Prosthetic Feet Olesnavage, Kathryn; Winter, Amos This paper presents an analysis of the rollover shape and energy storage and return in a prosthetic foot made from a compliant cantilevered beam. The rollover shape of a prosthetic foot is defined as the path of the center of pressure along the bottom of the foot during stance phase of gait, from heel strike to toe off. This path is rotated into the reference frame of the ankle-knee segment of the leg, which is held fixed. In order to achieve correct limb loading and gait kinematics, it is important that a prosthetic foot both mimic the physiological rollover shape and maximize energy storage and return. The majority of prosthetic feet available on the market are cantilever beam-type feet that emulate ankle dorsiflexion through beam bending. In this study, we show analytically that a prosthetic foot consisting of a beam with constant or monotonically decreasing cross-section cannot replicate physiological rollover shape; the foot is either too stiff when the ground reaction force (GRF) acts near the ankle, or too compliant when the GRF acts near the toe. A rigid constraint is required to prevent the foot from over-deflecting. Using finite element analysis (FEA), we investigated how closely a cantilever beam with constrained maximum deflection could mimic physiological rollover shape and energy storage/return during stance phase. A constrained beam with constant cross-section is able to replicate physiological rollover shape with R[superscript 2] = 0.86. The ratio of the strain energy stored and returned by the beam compared to the ideal energy storage and return is 0.504. This paper determines that there is a trade off between rollover shape and energy storage and return in cantilever beam-type prosthetic feet. The method and results presented in this paper demonstrate a useful tool in early stage prosthetic foot design that can be used to predict the rollover shape and energy storage of any type of prosthetic foot.

2014-08-01T00:00:00Z Narang, Yashraj Shyam Winter, Amos https://hdl.handle.net/1721.1/98255 2022-09-27T19:55:38Z 2014-08-01T00:00:00Z

Effects of Prosthesis Mass on Hip Energetics, Prosthetic Knee Torque, and Prosthetic Knee Stiffness and Damping Parameters Required for Transfemoral Amputees to Walk With Normative Kinematics Narang, Yashraj Shyam; Winter, Amos We quantify how the hip energetics and knee torque required for an above-knee prosthesis user to walk with the kinematics of able-bodied humans vary with the inertial properties of the prosthesis. We also select and optimize passive mechanical components for a prosthetic knee to accurately reproduce the required knee torque. Previous theoretical studies have typically investigated the effects of prosthesis inertial properties on energetic parameters by modifying both mass and mass distribution of the prosthesis and computing kinetic and energetic parameters only during swing. Using inverse dynamics, we determined the effects of independently modifying mass and mass distribution of the prosthesis, and we computed parameters during both stance and swing. Results showed that reducing prosthesis mass significantly affected hip energetics, whereas reducing mass distribution did not. Reducing prosthesis mass to 25% of the mass of a physiological leg decreased peak stance hip power by 26%, average swing hip power by 74%, and absolute hip work over the gait cycle by 22%. Previous studies have also typically optimized prosthetic knee components to reproduce the knee torque generated by able-bodied humans walking with normative kinematics. However, because the prosthetic leg of an above-knee prosthesis user weighs significantly less than a physiological leg, the knee torque required for above-knee prosthesis users to walk with these kinematics may be significantly different. Again using inverse dynamics, it was found that changes in prosthesis mass and mass distribution significantly affected this required torque. Reducing the mass of the prosthesis to 25% of the mass of the physiological leg increased peak stance torque by 43% and decreased peak swing torque by 76%. The knee power required for an above-knee prosthesis user to walk with the kinematics of able-bodied humans was analyzed to select passive mechanical components for the prosthetic knee. The coefficients of the components were then optimized to replicate the torque required to walk with the kinematics of able-bodied humans. A prosthetic knee containing a single linear spring and two constant-force dampers was found to accurately replicate the targeted torque (R[superscript 2]=0.90 for a typical prosthesis). Optimal spring coefficients were found to be relatively insensitive to mass alterations of the prosthetic leg, but optimal damping coefficients were sensitive. In particular, as the masses of the segments of the prosthetic leg were altered between 25% and 100% of able-bodied values, the optimal damping coefficient of the second damper varied by 330%, with foot mass alterations having the greatest effect on its value.

2014-08-01T00:00:00Z Ricks, Sean T. Lewandowski, John Robert Lim, Emmanuel Wendell, Dawn Winter, Amos G. https://hdl.handle.net/1721.1/98254 2022-09-28T12:47:32Z 2014-08-01T00:00:00Z

Development of a Design Tool for Flow Rate Optimization in the Tata Swach Water Filter Ricks, Sean T.; Lewandowski, John Robert; Lim, Emmanuel; Wendell, Dawn; Winter, Amos G. When developing a first-generation product, an iterative approach often yields the shortest time-to-market. In order to optimize its performance, however, a fundamental understanding of the theory governing its operation becomes necessary. This paper details the optimization of the Tata Swach, a consumer water purifier produced for India. The primary objective of the work was to increase flow rate while considering other factors such as cost, manufacturability, and efficacy. A mathematical model of the flow characteristics through the filter was developed. Based on this model, a design tool was created to allow designers to predict flow behavior without prototyping, significantly reducing the necessity of iteration. Sensitivity analysis was used to identify simple ways to increase flow rate as well as potential weak points in the design. Finally, it was demonstrated that maximum flow rate can be increased by 50% by increasing the diameter of a flow-restricting feature while simultaneously increasing the length of the active purification zone. This can be accomplished without significantly affecting cost, manufacturability, and efficacy.

2014-08-01T00:00:00Z Buchman, Michael R. Winter, Amos https://hdl.handle.net/1721.1/98220 2022-09-27T20:26:26Z 2014-08-01T00:00:00Z

Method for Turbocharging Single Cylinder Four Stroke Engines Buchman, Michael R.; Winter, Amos This paper presents a feasibility study of a method for turbocharging single cylinder, four-stroke internal combustion engines. Turbocharging is not conventionally used with single cylinder engines because of the timing mismatch between when the turbo is powered, during the exhaust stroke, and when it can deliver air to the cylinder, during the intake stroke. The proposed solution involves an air capacitor on the intake side of the engine between the turbocharger and intake valves. The capacitor acts as a buffer and would be implemented as a new style of intake manifold with a larger volume than traditional systems. In order for the air capacitor to be practical, it needs to be sized large enough to maintain the turbocharger pressure during the intake stroke, cause minimal turbo lag, and significantly increase the density of the intake air. By creating multiple flow models of air through the turbocharged engine system, we found that the optimal size air capacitor is between four and five times the engine capacity. For a capacitor sized for a one-liter engine, the lag time was found to be approximately two seconds, which would be acceptable for slowly accelerating applications such as tractors, or steady state applications such as generators. The density increase that can be achieved in the capacitor, compared to air at standard ambient temperature and pressure, was found to vary between fifty percent for adiabatic compression and no heat transfer from the capacitor, to eighty percent for perfect heat transfer. These increases in density are proportional to, to first order, the anticipated power increases that could be realized with a turbocharger and air capacitor system applied to a single cylinder, four-stroke engine.

2014-08-01T00:00:00Z Narang, Yashraj Shyam Winter, Amos Arelekatti, Venkata N. M. https://hdl.handle.net/1721.1/98214 2022-10-01T14:41:44Z 2015-07-01T00:00:00Z

The Effects of Prosthesis Inertial Properties on Prosthetic Knee Moment and Hip Energetics Required to Achieve Able-bodied Kinematics Narang, Yashraj Shyam; Winter, Amos; Arelekatti, Venkata N. M. There is a major need in the developing world for a low-cost prosthetic knee that enables users to walk with able-bodied kinematics and low energy expenditure. To efficiently design such a knee, the relationship between the inertial properties of a prosthetic leg and joint kinetics and energetics must be determined. In this paper, using inverse dynamics, the theoretical effects of varying the inertial properties of an above-knee prosthesis on the prosthetic knee moment, hip power, and absolute hip work required for walking with ablebodied kinematics were quantified. The effects of independently varying mass and moment of inertia of the prosthesis, as well as independently varying the masses of each prosthesis segment, were also compared. Decreasing prosthesis mass to 25% of physiological leg mass increased peak late-stance knee moment by 43% and decreased peak swing knee moment by 76%. In addition, it reduced peak stance hip power by 26%, average swing hip power by 76%, and absolute hip work by 22%. Decreasing upper leg mass to 25% of its physiological value reduced absolute hip work by just 2%, whereas decreasing lower leg and foot mass reduced work by up to 22%, with foot mass having the greater effect. Results are reported in the form of parametric illustrations that can be utilized by researchers, designers, and prosthetists. The methods and outcomes presented have the potential to improve prosthetic knee component selection, facilitate ablebodied kinematics, and reduce energy expenditure for users of low-cost, passive knees in developing countries, as well as for users of advanced active knees in developed countries.

2015-07-01T00:00:00Z Inam, Wardah Strawser, Daniel DeWitt Afridi, Khurram Ram, Rajeev J. Perreault, David J. https://hdl.handle.net/1721.1/97188 2022-10-01T13:39:38Z 2015-06-01T00:00:00Z

Architecture and System Analysis of Microgrids with Peer-to-Peer Electricity Sharing to Create a Marketplace which Enables Energy Access Inam, Wardah; Strawser, Daniel DeWitt; Afridi, Khurram; Ram, Rajeev J.; Perreault, David J. More than 1.3 billion people in the world lack access to electricity and this energy poverty is a major barrier to human development. This paper describes a new concept of peer-to-peer electricity sharing which creates a marketplace for electricity. In this marketplace, the people who can afford power generating sources such as solar panels can sell electricity to people who are unable to afford generating sources or who might have access to electricity but require more electricity at certain times. These ad-hoc microgrids created by sharing of resources provide affordable electricity and are enabled by a Power Management Unit (PMU) described in this paper.

2015-06-01T00:00:00Z Satat, Guy Barsi, Christopher Raskar, Ramesh https://hdl.handle.net/1721.1/92732 2022-09-26T17:01:37Z 2014-05-01T00:00:00Z

Skin perfusion photography Satat, Guy; Barsi, Christopher; Raskar, Ramesh The separation of global and direct light components of a scene is highly useful for scene analysis, as each component offers different information about illumination-scene-detector interactions. Relying on ray optics, the technique is important in computational photography, but it is often under appreciated in the biomedical imaging community, where wave interference effects are utilized. Nevertheless, such coherent optical systems lend themselves naturally to global-direct separation methods because of the high spatial frequency nature of speckle interference patterns. Here, we extend global-direct separation to laser speckle contrast imaging (LSCI) system to reconstruct speed maps of blood flow in skin. We compare experimental results with a speckle formation model of moving objects and show that the reconstructed map of skin perfusion is improved over the conventional case.

2014-05-01T00:00:00Z