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Articles 2011 - 2040 of 2904

Full-Text Articles in Engineering

A Viscoelastic Model For Human Prolapsed Vaginal Wall Tissue, Milton Ma Jan 2011

A Viscoelastic Model For Human Prolapsed Vaginal Wall Tissue, Milton Ma

Bioengineering Theses - Archive

Pelvic organ prolapse (POP) affects thousands of elderly women each year. Improvements in surgical repair could benefit from the understanding of the biomechanical properties of the vaginal wall (VW) tissues to better tailor the needed repair. VW tissue property has been measured by uniaxial tensile test on excised fresh human anterior VW tissues. Data available, however, are limited to elastic modulus obtained in vitro. Recently, in vivo biomechanical data of VW from POP patients have been obtained by adapting a cutometer-like device, the BTC-2000TM (SRLI). The Voigt and Standard Linear models in conjunction with the framework of quasi-linear viscoelasticity theory …

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3-Dimensional Scanning And Reconstruction Using A Modified Hrt-Rcm Corneal Confocal Microscope, Saurabh Vaidya Jan 2011

3-Dimensional Scanning And Reconstruction Using A Modified Hrt-Rcm Corneal Confocal Microscope, Saurabh Vaidya

Bioengineering Theses - Archive

The HRT II - Rostock Corneal Module (HRT II-RCM) provides excellent resolution, contrast and optical sectioning capability for cornea imaging. It offers the most detailed views of cornea structure and pathology. However, the major limitation of this microscope is its scanning method. It has a threaded dial on the front side of the microscope which is coupled to the objective, and this dial has to be rotated manually to change the focal plane and to scan through the cornea.The dial is within inches of the cornea. During the scans, manual control causes serious interference and degrades the quality of the …

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Optimization Of Hydrogel System For Complex Wound Healing, Nikhil Vilas Aphale Jan 2011

Optimization Of Hydrogel System For Complex Wound Healing, Nikhil Vilas Aphale

Bioengineering Theses - Archive

Various conventional therapies and preventive measures have been developed and used for treating complex wounds; however, patients with complex wounds still develop wound infection and consist of delayed wound healing. These limitations necessitate the development of a novel therapeutic system, which is cost effective, easily apply onto the complex wounds, and consists of an efficient therapeutic nature. An in situ forming hydrogel system, made up of a novel biodegradable elastomer poly (ethylene glycol) maleate citrate (PEGMC), was designed and optimized for complex wound healing. Biocompatibility of this hydrogel system was studied by determining the toxicity of both the formation factors, …

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Process Modeling System For Press Cure, Closed-Cavity Tooled Thick Composites, Arven H. Saunders Jan 2011

Process Modeling System For Press Cure, Closed-Cavity Tooled Thick Composites, Arven H. Saunders

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Thick structural composite parts often use press curing with closed-cavity tooling for achieving dimensional tolerances. A commonly encountered defect for these parts is fiber waviness, whick limits its structural strength. The yield for such parts often suffers due to trial and error methods used to develop successful cure processes. In addition, yield for these parts suffers due to material variation. The objectives of this research were to: develop and validate a simplified yet practical cure process model for press cured thick composite parts, utilize the model in order to seek time-efficient optimized cure processes, investigate the effects of material variation …

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Control Of Airship Motion In The Presence Of Wind, Jatuporn Nakpiam Jan 2011

Control Of Airship Motion In The Presence Of Wind, Jatuporn Nakpiam

Mechanical and Aerospace Engineering Theses - Archive

This research effort develops a guidance and control system for a small airship to fly through assigned waypoints in the three dimensional space with a desired speed in the presence of wind and wind gust. In the control system development and validation, a simulation environment based on the nonlinear 6-DOF model of an airship, including the effect of the wind, is used. The airship has five control variables, the main thrust, the main thrust angle, the tail thrust, elevator and rudder deflections. The effectiveness of the elevator and rudder degrades as the speed of the airship decreases. The controller design …

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Development Of Multimodal Imaging System Combined With Laser Microbeam For Nanoscale Manipulation And Characterization., Ninad Ingle Jan 2011

Development Of Multimodal Imaging System Combined With Laser Microbeam For Nanoscale Manipulation And Characterization., Ninad Ingle

Material Science and Engineering Theses - Archive

Optical microscopy has fascinated biologists for probing and observing cellular structure while performing scientific research. While numerous wide-field and scanning microscopic techniques are being developed for probing cellular structure and function with high spatial and temporal resolution, mapping of complete biochemical, material and structural properties of the cell in three dimensions requires integration of multiple microscopic imaging techniques. In this thesis, conventional phase contrast microscopy and epifluorescence microscopy techniques were combined with other imaging methods such as digital holography microscopy (DHM) also known as quantitative phase microscopy, atomic force microscopy (AFM), near-field scanning optical microscopy (NSOM), total internal reflection fluorescence …

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Evaluation Of Resistivity Imaging (Ri) Method For Determining Unknown Deep Foundation Depth, Mohammad Sadik Khan Jan 2011

Evaluation Of Resistivity Imaging (Ri) Method For Determining Unknown Deep Foundation Depth, Mohammad Sadik Khan

Civil Engineering Theses - Archive

There are approximately 580,000 highway bridges in the National Bridge inventory and 104,000 of these bridges are estimated to have unknown foundations type and/or depth. Determining unknown foundation length and type of bridge foundation is becoming an important issue for State DOTs to ensure the safety of the bridge. There are several methods available to determine unknown foundation depth based on specific site conditions and type of foundation to be tested. Resistivity Imaging (RI) is a non destructive method to investigate the subsurface condition. The objective of current study was to determine unknown bridge foundation depth of three bridges at …

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Carbon Footprint Analysis Of A Large Diameter Water Transmission Pipeline Installation, Lalit Chilana Jan 2011

Carbon Footprint Analysis Of A Large Diameter Water Transmission Pipeline Installation, Lalit Chilana

Civil Engineering Theses - Archive

The term pipeline refers to a long line of connected segments of pipe, with pumps, valves, control devices, and other equipment or facilities needed for operating the system. Water transmission pipelines are generally large diameter (more than 12 in.) pipes which transport the water from one place to another. Installation of these pipes is a complex process due to variability of ground conditions over long distance installations. Sometimes, it is difficult to relate pipelines to the environment because of the out of sight nature. But it follows a close relationship with our environment due to various energy consuming activities involved …

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Experimental Investigation Of The Behavior Of The Steel Reinforced High Density Polyethylene And Corrugated Metal Pipe, Safa Sadat Masajedian Jan 2011

Experimental Investigation Of The Behavior Of The Steel Reinforced High Density Polyethylene And Corrugated Metal Pipe, Safa Sadat Masajedian

Civil Engineering Theses - Archive

Steel reinforced high density polyethylene pipes are gaining popularity these days because of their good performance and advantages of them in comparison to the other pipe materials. By inverting the steel ribs vertically in to the HDPE materials, strength of steel and flexibility and light weight of HDPE materials have been combined. However due the limited study in this area, the failure modes and design parameters are not classified.This study investigates the behavior and failure modes of SR-HDPE pipes under the simulated soil load and compares the results with the data obtained from the test on corrugated metal pipe under …

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Evaluation Of Building Information Modeling Applications For Small Construction Companies, Agustin Villafana Jan 2011

Evaluation Of Building Information Modeling Applications For Small Construction Companies, Agustin Villafana

Civil Engineering Theses - Archive

This thesis concerns developing recommendations to help small construction company's transition from traditional two dimensional plans to a Building Information Modeling (BIM) management process. Due to the cost of implementing BIM, the primary focus of the thesis is onthe transitioning state of these two management areas in an effort to facilitate full integration of smaller contractors into BIM technologies at a future time.Three case studies are used to assess and evaluate the effects of building information modeling on the schedule, material procurement, and information modeling aspects of a project. The intent of the case studies is to demonstrate a net …

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An Overview Of Mitigation Strategies For Settlements Under Bridge Approach Slabs, Raja Veerendra Yenigalla Jan 2011

An Overview Of Mitigation Strategies For Settlements Under Bridge Approach Slabs, Raja Veerendra Yenigalla

Civil Engineering Theses - Archive

Settlement and heave related movements of bridge approach slabs relative to bridge decks create a bump in the roadway causing inconvenience to the travelling public and at times so large as to make travelling unsafe. Hence, it is important to adopt suitable remedial methods to mitigate the approach settlements so as to ensure safe traveling conditions and also to decrease the repair/maintenance costs. This thesis presents an overview of a few case studies on different mitigation techniques applied on bridge approach settlement problems at various locations in the state of Texas. The methods employed to mitigate the settlement including Polyurethane …

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Use Of Steel Fiber Reinforced Concrete In Structural Members With Highly Complex Stress Fields, Tarun Pareek Jan 2011

Use Of Steel Fiber Reinforced Concrete In Structural Members With Highly Complex Stress Fields, Tarun Pareek

Civil Engineering Theses - Archive

Reinforced concrete (RC) members with significant geometric discontinuities and complex stress distributions under loading require considerable analyses and usually complicated reinforcement detailing. RC members with large openings are one of the examples. These large openings may interrupt the load transfer by direct concrete struts and cause substantial decrease in strength and unpredictable failure modes. The reinforcement detailing of these concrete members based on strut-and-tie models (STMs) is generally complicated and very often, these models cannot predict the failure mechanism due to localized damages. The actual stress fields in such members are typically very different from that predicated by STMs, as …

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Targeted Nanoparticles For Cancer Therapy: Promises And Challenge, Kytai Truong Nguyen Jan 2011

Targeted Nanoparticles For Cancer Therapy: Promises And Challenge, Kytai Truong Nguyen

Bioengineering Faculty Publications - Archive

No abstract provided.

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Implementation Of Complexity Reduction Algorithm For Intra Mode Selection In H.264/Avc, Santosh Kumar Muniyappa Jan 2011

Implementation Of Complexity Reduction Algorithm For Intra Mode Selection In H.264/Avc, Santosh Kumar Muniyappa

Electrical Engineering Theses - Archive

For applications with low computational capabilities like handheld devices, it is necessary that the encoding complexity is minimal. But H.264, which is the most widely accepted video platform employs several powerful coding techniques that increase encoding complexity. Hence, the objective of this thesis is to implement an algorithm which reduces the encoding complexity by about 25%, but retains the quality of the existing intra prediction algorithm. H.264 offers nine modes for intra prediction of 4x4 luminance blocks, which includes DC prediction and eight directional modes (N4). For regions with less spatial detail, H.264 supports 16x16 intra coding, where in one …

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Low Complexity Avs-M Using Machine Learning Algorithm C4.5, Pragnesh Ramolia Jan 2011

Low Complexity Avs-M Using Machine Learning Algorithm C4.5, Pragnesh Ramolia

Electrical Engineering Theses - Archive

AVS China is the latest video coding standard developed by the AVS work group of China employing the latest video coding tools for achieving high compression while preserving the quality of the video [15]. AVS China video standard has been proven superior to the existing video standards such as MPEG-2 and MPEG-4 part 2, in terms of reduced complexity and coding efficiency. AVS is a set of integrated standard system which contains systems, video, audio and media copyright management. AVS-M, the 7th part of the system is video codec targeting mobile devices. AVS-M uses high efficiency tools like macroblock portioning, …

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Estimation Of Thermal Impedance Parameters Of Silicon Germanium Heterojunction Bipolar Transistors, Arun Thomas Karingada Jan 2011

Estimation Of Thermal Impedance Parameters Of Silicon Germanium Heterojunction Bipolar Transistors, Arun Thomas Karingada

Electrical Engineering Theses - Archive

Silicon Germanium (SiGe) hetero junction bipolar transistors (HBTs) are used in a variety of circuits like analog mixed signal and RF(radio frequency ) circuits. As the device gets smaller these days the self heating affects the performance of the SiGe HBTs. This paper uses theoretical methods based on device geometry and material properties to calculate the thermal resistance and thermal capacitance of SiGe HBT. In addition to theoretical estimations time domain, frequency domain and DC measurements are done on National Semiconductor's CBC8 HBTs which is used to extract the values of thermal impedance parameters.

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Optimal Path Planning, Implementation And Simulation For A Breast Biopsy System, Sridhar Rajaram Jan 2011

Optimal Path Planning, Implementation And Simulation For A Breast Biopsy System, Sridhar Rajaram

Electrical Engineering Theses - Archive

Core needle biopsy is a non-invasive method of confirming the presence of cancer cells in the breast. Image guided breast biopsy is a procedure performed to extract suspicious tissue and test it under the microscope for cancer. Common imaging modalities used are X-ray, MRI and Ultrasound. X-rays and MRI involve ionizing radiation which is harmful when a patient is suspected to have cancer. Apart from this, patients go through much discomfort during biopsy. Sometimes, multiple incisions are required to extract the desired tissue which prolongs the discomfort.This thesis describes a breast biopsy system using Ultrasound images. The main aim of …

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An Identifier-Tracking Based Model Reference Adaptive Control Without The Knowledge Of Relative Degree, Xiao Hu Jan 2011

An Identifier-Tracking Based Model Reference Adaptive Control Without The Knowledge Of Relative Degree, Xiao Hu

Electrical Engineering Dissertations - Archive

The purpose of Model Reference Adaptive Control (MRAC) is to create a controller with adjustable parameters to obtain the desired response from a reference model. One of the basic assumptions in MRAC is that the relative degree of the plant is known exactly. However, this assumption is too restrictive for some practical plants, since the relative degree of the plant may not be specified in advance. The study of MRAC with unknown relative degree has been important from both theoretical and practical point of view. This dissertation focuses on a new design approach for the model reference adaptive control of …

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Mixed Integer Programming Models For Selecting Ground-Level Ozone Control Strategies, Wei-Che Hsu Jan 2011

Mixed Integer Programming Models For Selecting Ground-Level Ozone Control Strategies, Wei-Che Hsu

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Under the Clean Air Act (CAA) in 1990, the U.S Environmental Protection Agency (EPA) was required to set National Ambient Air Quality Standards (NAAQS) for six common air pollutants that are considered harmful to public health and the environment. Ground–level ozone was one of the six criteria pollutants monitored by the EPA and considered the most widespread health threat. Two precursors of ground level ozone are nitrogen oxides (NOx) and volatile organic compounds (VOC) and the common sources of these two precursors include on–road vehicles, non–road engines, area sources, point sources, and biogenic and miscellaneous sources. An area …

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The Pmu-Based Parameter Identification For Synchronous Generator Dynamic Model, Chin-Chu Tsai Jan 2011

The Pmu-Based Parameter Identification For Synchronous Generator Dynamic Model, Chin-Chu Tsai

Electrical Engineering Dissertations - Archive

Power systems have become more complex and are found to be consistently operating closer to their stability limits under the deregulated environment. Power system dynamic simulation, which provides significant insight into the dynamic characteristics of system, is one of the most important tools for both planning and operation engineers. Since it heavily relies on the simulation result to make decisions related to operation strategies, grid expansion plain, facility maintenances schedules, an accurate simulation result can avoid unnecessary facility investment and improve the security of the system operation. However, the simulation result is affected by the model and parameters of the …

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Intelligent Control And Cooperation For Mobile Robots, Petru Emanuel Stingu Jan 2011

Intelligent Control And Cooperation For Mobile Robots, Petru Emanuel Stingu

Electrical Engineering Dissertations - Archive

The topic discussed in this work addresses the current research being conducted at the Automation & Robotics Research Institute in the areas of UAV quadrotor control and heterogenous multi-vehicle cooperation. Autonomy can be successfully achieved by a robot under the following conditions: the robot has to be able to acquire knowledge about the environment and itself, and it also has to be able to reason under uncertainty. The control system must react quickly to immediate challenges, but also has to slowly adapt and improve based on accumulated knowledge. The major contribution of this work is the transfer of the ADP …

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Mode Structure Of A Noiseless Phase-Sensitive Image Amplifier, Muthiah Annamalai Jan 2011

Mode Structure Of A Noiseless Phase-Sensitive Image Amplifier, Muthiah Annamalai

Electrical Engineering Dissertations - Archive

Optical parametric amplifiers (OPAs) configured as phase-sensitive amplifiers (PSAs) can be used for noiseless optical image amplification, generation of non-classical states of light, and, in particular, for multimode squeezed light generation. For all these applications and for effective use of the quantum properties of the multimode PSA, we need to know its independently squeezed (or amplified) eigenmodes. First we present the quantum theory of a spatially multimode traveling-wave PSA pumped by a high-power pump beam with arbitrary spatial profile. To quantitatively identify the Green's function of the PSA, we have developed a semi-analytical coupled-mode-theory of the PSA using 2D Hermite-Gaussian …

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The Design Of Cmos Impulse Generators For Ultra-Wideband Communication And Radar Systems, Ju-Ching Li Jan 2011

The Design Of Cmos Impulse Generators For Ultra-Wideband Communication And Radar Systems, Ju-Ching Li

Electrical Engineering Dissertations - Archive

Impulse generators play an important role in the ultra-wideband (UWB) systems. Particularly in the transmitter, impulse generator performs an interface between input data and the antenna determining the overall performance of the transmitter. After the federal communication commission (FCC) revised the rules for UWB systems usages, the design of impulse generators has been pursued and yet challenging especially using CMOS technology. In this dissertation, three impulse generators are presented with analytical explanations, simulations, and measurements. First, the design and simulation of an impulse generator using TSMC 0.18 ìm CMOS technology is presented. The operating frequency band of the impulse generator …

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Radar Sensor Networks: Waveform Design, Mimo And Compressive Sensing, Lei Xu Jan 2011

Radar Sensor Networks: Waveform Design, Mimo And Compressive Sensing, Lei Xu

Electrical Engineering Dissertations - Archive

In this dissertation, we have studied totally eight topics which are focused on but not limited to radar sensor networks (RSN) from a signal processing perspective. We propose the definitions of ZCZ/LCZ (Zero Correlation Zone/Low Correlation Zone) sequence-pair sets, provided three methods to construct optimized optimized punctured LCZ/ZCZ sequence-pair sets and study their properties in chapter 2 and 3. We further investigate the waveform design problem for radar system, radar sensor network, sonar sensor network and MIMO radar system from chapter 4 to chapter 7. In addition, we study radar sensor network from the view of information theory in chapter …

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Numerical Modeling Of Microwave Emission From Irregular Layer, Luis Manuel Camacho-Velazquez Jan 2011

Numerical Modeling Of Microwave Emission From Irregular Layer, Luis Manuel Camacho-Velazquez

Electrical Engineering Dissertations - Archive

A numerical approach to model the microwave emission from an irregular layer is developed. The phase matrix of the layer components as well as the emission characteristics are estimated using a numerical approach, namely the Finite-Difference Time-Domain (FDTD) method. The phase matrix is then integrated into a layer model that accounts for the scattering between the layer and ground, using the radiative transfer theory. The effects of interface roughness on emission are incorporated into the model through the surface phase matrices, which are computed using the Integral Equation Model (IEM).The validity of the phase matrices computation is tested against theoretical …

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The Complex Gaussian Scale Mixtures Of Complex Wavelet Coefficients And Applications, Yothin Rakvongthai Jan 2011

The Complex Gaussian Scale Mixtures Of Complex Wavelet Coefficients And Applications, Yothin Rakvongthai

Electrical Engineering Dissertations - Archive

In this thesis, the complex Gaussian scale mixture (CGSM), which is an extension of the Gaussian scale mixture (GSM) for real-valued random variables to the complex case, is presented to model the complex wavelet coefficients. Along with some related propositions and miscellaneous results, the probability density functions (pdf) of the magnitude and phase of the complex random variable are presented. Specifically, the closed forms of the magnitude pdf for the case of complex generalized Gaussian distribution (CGGD) and the phase pdf for the general case are presented. Subsequently, the pdf of the relative phase is derived.Moreover, parameter estimation methods in …

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Miniature Wireless Gastrostimulator, Sanchali Deb Jan 2011

Miniature Wireless Gastrostimulator, Sanchali Deb

Electrical Engineering Dissertations - Archive

Gastroparesis is a common disorder caused to patients suffering from diabetes, cancer and Parkinson's disease. Gastric electrical stimulation (GES) has attracted significant attention in the treatment for Gastroparesis. GES inflicts electrical pulses to the stomach tissues to help regain normal motility and hence reduces Gastroparesis symptoms like vomiting, nausea, abdominal bloating etc. Conventional gastric stimulator needs a long surgery to be implanted and it is a big pacemaker like device that runs by a non-rechargeable battery. It has to be replaced once the battery gets exhausted. Hence another round of surgery is done when these devices are needed to be …

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Localization Of Short Circuit Faults In The Power Distribution Networks, Omkar Deepak Limaye Jan 2011

Localization Of Short Circuit Faults In The Power Distribution Networks, Omkar Deepak Limaye

Electrical Engineering Theses - Archive

This thesis summarizes the research efforts on localizing short-circuit faults in power distribution networks. Specifically, an experimental testbed is constructed to emulate realistic power distribution networks; various short-circuit faults are artificially created in the testbed; voltages/currents are measured over the testbed; and finally, fault localization is achieved by analyzing the measurement data.Two types of power distribution networks are analyzed: serial/radial and grid/mesh networks. In the serial network, a scheme based on terminal voltage and current measurements is developed. Two voltage profiles, namely "forward voltage profile" and "backward voltage profile," are plotted and their intersection is estimated as the fault location. …

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Bridge Monitoring System Using Embedded Computer Vision, Kenan Modi Jan 2011

Bridge Monitoring System Using Embedded Computer Vision, Kenan Modi

Electrical Engineering Theses - Archive

The bridges and overpass are integral part of road network. These structures deteriorate the moment the construction is over. The factors of deterioration are impact loads of vehicles, natural factors such as wind, rain, earthquake, floods, etc. These deterioration leads to structural failures. In order to prevent failures these structure should be periodically monitored and maintained. In this research project a novel method for early detection of bridge failure using computer vision application and 3D road profiling system is proposed. The objective of this research work to check the feasibility of this bridge monitoring system for any structural movement detection. …

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Development Of Prosthetic Skin, Rohit Kilaru Jan 2011

Development Of Prosthetic Skin, Rohit Kilaru

Electrical Engineering Theses - Archive

The objective of this research was to embed tactile sensors in polyimides. This novel method could be utilized to realize prosthetic skin for sensing different kinds of mechanical stimuli. Tactile sensors have an increasing demand in medical sectors: upper and lower-limb prosthetics and in the industrial sectors: robot end-effectors, grippers and manipulators. The sensors developed are targeted for prosthetic arm tactile sensing applications. Current work presents piezoresistive differential pressure sensors fabricated on flexible polyimide film or substrate.A unique technique to bond a flexible superstrate polyimide layer to a MEMS tactile sensor array is presented in this thesis. The sensor is …

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