Results :: Search Electronic Theses and Dissertations (ETDs)

Your search for Keyword mems cell stifness resulted in 65 match(es).

Back to search page

View next 25 results

Analysis and Design of mems Scan Mirrors Using Periodically Stiffened Silicon Nitride: Author: Lutzenberger, Bert Jeffrey; Date: 2006-05-15; Program: Civil Engineering; Abstract: This research presents a novel fabrication method combining surface and bulk micromachining techniques to deposit mechanically stiffened silicon nitride films for use in mems fabrication. The stiffened silicon nitride film consists of a thin (~1.5 um) top sheet with stiffening fins molded to the back of the film. In the final configuration, the fins extend between 15 um and 40 um vertically from the back of the film. The molded fins are arranged into periodic square and hexagonal cell configurations ranging in size from 10 um to 250 um. The periodic cells significantly increase the bending sti...; Download File | View full details

mems 3-D Scan Mirror for an Endoscopic Confocal Microscope: Author: Shao, Yuhe; Date: 2005-12-15; Program: Engineering; Abstract: Optical mems is at a very exciting stage and has become an enabling technology for a variety of applications in telecommunications and high-resolution display and imaging. Among many novel mems devices, mems scanners and deformable membrane mirrors are especially useful for scanned-beam imaging systems. mems scanners are usually used for laser beam scanning. Deformable mirrors provide an approach to modify the optical wavefront adaptively. In optical microsystems, packaging is often a critical part of the system design. Combining functionalities at a single device can reduce complexity of the ...; Download File | View full details

Application of the Van Der Pauw Structure as a Piezoresistive Pressure Sensor - A Numerical Study: Author: Law, Jesse Townsend; Date: 2007-08-15; Program: Mechanical Engineering; Abstract: This research characterizes a piezoresistive sensor under variations of both size and orientation with respect to the silicon crystal lattice for its application to mems pressure sensing. The sensor to be studied is a four-terminal piezoresistive sensor commonly referred to as a van der Pauw (VDP) structure. It is observed that the sensitivity of the VDP sensor is over three times higher than the conventional filament type Wheatstone bridge resistor. With mems devices being used in applications which continually necessitate smaller size, characterizing the effect of size and orientation of a V...; Download File | View full details

Non-Intrusive Fuel cell Load Interaction Monitoring: Author: Lackey, John David; Date: 2006-05-15; Program: Electrical Engineering; Abstract: This thesis presents the development of a non-intrusive method for monitoring fuel cells. The instrumentation demands that only the readily accessible AC output terminals of the fuel cell be monitored, making it easy to install on an existing fuel cell. The monitoring hardware senses the current and voltage output of the fuel cell and converts the measurements into the digital domain. The original algorithm to process the data was the Non-Intrusive Load Monitor (NILM) system which detects specific events, classifies and stores them. The software that is described in this thesis is a data speci...; Download File | View full details

Design, fabrication, and testing of the van der Pauw piezoresistive structure for pressure sensing: Author: Cassel, Robert Douglas; Date: 2008-05-15; Program: Mechanical Engineering; Abstract: The project characterizes a piezoresistive sensor under variations of both size and orientation with respect to the silicon crystal lattice for its application to mems pressure sensing. The sensor to be studied is a four-terminal piezoresistive sensor commonly referred to as a van der Pauw (VDP) structure. The VDP sensor is used primarily in sheet resistance measurements, but has also been determined to be useful in determining the stress components at a point on (100) and (111) silicon wafer surfaces. In a previous study, our team has determined the relation between the biaxial stress state a...; Download File | View full details

Select Procyanidins induce gammadelta T cell activation and proliferation: Author: Holderness, Jeffery Scott; Date: 2008-05-15; Program: Veterinary Molecular Biology; Abstract: Many pharmaceutical drugs in use today were originally identified in plants from traditional medicine. However, there remain many plants in traditional medicine that produce confusing immune responses and are therefore unlikely candidates for pharmaceutical drugs. The effects of some of the traditional medicines that induce these confusing immune responses may now be explained by recent advances in the characterization of our immune system, namely in our understanding of the unique functions of the γδ T cell. These γδ T cell functions include t...; Download File | View full details

Modeling and Transient Degradation of Proton Exchange Membrane Fuel cells: Author: Pasricha, Sandip; Date: 2006-05-15; Program: Electrical Engineering; Abstract: This thesis presents a model based approach to describe proton exchange membrane (PEM) fuel cell degradation with time. This degradation study involves analysis of voltage and current profiles of PEM membranes under transient load conditions. The data is collected from 80 membranes in an Independence1000 1000W PEM system over the life span of the membrane. The thesis also presents PEM fuel cell models developed and validated on a 500W SR-12 commercial PEM stack. Several static models from the literature are reviewed in terms of physical effects, parameterized for identification, and compared u...; Download File | View full details

Spatial and temporal patterns of antimicrobial action against Staphylococcus epidermidis biofilms: Author: Davison, William Marshall; Date: 2008-05-15; Program: Engineering; Abstract: This study investigated the spatio-temporal patterns of antimicrobial action against Staphylococcus epidermidis planktonic and biofilm bacteria. Bacteria were stained with a fluorogenic esterase substrate, Calcein-AM, which allowed for the visualization of cells that possessed intact cell membranes. Four different antimicrobial agents were tested for their effect upon cell viability as associated with membrane integrity. The four biocides were Barquat®, glutaraldehyde, chlorine, and nisin. Planktonic bacteria were analyzed with flow cytometry, observing fluorescence loss during 1 h ...; Download File | View full details

Investigating host response to viral infection through proteomics: a study of murine norovirus: Author: Furman, Linnzi M.; Date: 2008-05-15; Program: Biochemistry; Abstract: Norovirus causes roughly 23 million cases of foodborne illnesses in the United States each year. While this virus was characterized over 30 years ago, it remains non-cultivatable in human cells, resulting in an incomplete understanding of the host cell's response to infection. However, in 2004 murine norovirus (MNV) was found to be cultivatable in mice and has since been successfully cultured in RAW 264.7 cells. MNV has become an important model system for studying norovirus, as it is structurally and genetically similar to human norovirus. A global proteomics approach using fluorescently tagg...; Download File | View full details

Chemical Sensors and Instrumentation Powered by Microbial Fuel cells: Author: Angathevar Veluchamy, Raaja Raajan; Date: 2007-12-15; Program: Chemical Engineering; Abstract: The use of microbial fuel cells to power electronic devices is inhibited by their low voltage and current outputs, therefore they cannot be used directly to power electronic devices without appropriate power management. The goal of the thesis is to power chemical sensors but currently there are no available sensor circuitries which can be operated at the low potential and current delivered by a microbial fuel cell. In this thesis, novel sensor circuitry and power management circuitry have been developed. The sensor circuitry can be programmed to operate any generic amperometric sensor and the ...; Download File | View full details

Power Management for Microbial Fuel cells: Author: Shantaram, Avinash; Date: 2005-05-15; Program: Environmental Engineering; Abstract: Monitoring parameters characterizing water quality, such as temperature, pH and concentrations of heavy metals in natural waters, is often followed by transmitting the data to remote receivers using telemetry systems. Such systems are commonly powered by batteries, which can be inconvenient at times because batteries have a limited lifetime and have to be recharged or replaced periodically to ensure that sufficient energy is available to power the electronics. To avoid these inconveniences, we have designed and tested a self-renewable power source, a microbial fuel cell, which has the potentia...; Download File | View full details

Development of a Novel High Performance Electrolyte Supported Solid Oxide Fuel cell: Author: Gentile, Paul Steven; Date: 2007-12-15; Program: Mechanical Engineering; Abstract: High power solid oxide fuel cell (SOFC) stacks are based on the planar design concept to yield high specific power densities. The key engineering challenges to planar stack reliability and robust operation is attaining low resistance interconnection of individual cells in series and hermetic sealing of interconnects. While stack design and contact paste development is paramount to address this issue, the basic design of the fuel cell introduces limitations. State-of-the-art anode supported cells (ASC) yield high power densities due to low ASR thin electrolytes, however, the asymmetrical design...; Download File | View full details

Electro-Optic Pockels cell Voltage Sensors for Accelerator Diagnostics: Author: Iverson, Adam Joseph; Date: 2004-08-15; Program: Electrical Engineering; Abstract: Three prototype electro-optic Pockels cell voltage sensors were fabricated, each using a different electro-optic crystal. These sensors were to be used in an electron particle accelerator with a pulse length outside of the working range of operation for current electrical B-dot probes. The three crystals of interest were bismuth germanium oxide (BGO), bismuth silicon oxide (BSO) and zinc selenide (ZnSe). Each crystal was bench tested at two different wavelengths to determine sensitivity. BSO was shown to be the most sensitive to voltage, followed by ZnSe. BGO was shown to be the least sensitiv...; Download File | View full details

Analysis of the Expression and Function of Chicken Protocadherin 1 in Neural Crest Migration and Peripheral Nervous System Formation: Author: Bononi, Judy; Date: 2007-08-15; Program: Neuroscience; Abstract: The necessary steps of development from a single cell to a multi-celled functional organism are complex. Many molecules have been identified and their roles characterized in this process. One interesting population of cells includes the highly migratory neural crest cells (NCCs) unique to the vertebrate embryo and existing transiently during early embryonic development. The NCCs migrate along specific pathways at specific timepoints, stop at target locations, differentiate and give rise to a variety of cell types and tissues. Trunk NCCs must choose between two different migratory pathways: the...; Download File | View full details

Modeling and Control of Hybrid Wind/Photovoltaic/Fuel cell Distributed Generation Systems: Author: Wang, Caisheng; Date: 2006-08-15; Program: Engineering; Abstract: Due to ever increasing energy consumption, rising public awareness of environmental protection, and steady progress in power deregulation, alternative (i.e., renewable and fuel cell based) distributed generation (DG) systems have attracted increased interest. Wind and photovoltaic (PV) power generation are two of the most promising renewable energy technologies. Fuel cell (FC) systems also show great potential in DG applications of the future due to their fast technology development and many merits they have, such as high efficiency, zero or low emission (of pollutant gases) and flexible modul...; Download File | View full details

A Microbial Fuel cell using Biomineralized Manganese Oxides as a Cathodic Reactant: Author: Rhoads, Allison Nicole; Date: 2005-05-15; Program: Environmental Engineering; Abstract: Microbial fuel cells were designed and operated utilizing microorganisms in both the anodic and cathodic compartments. In the cathodic compartment we used Leptothrix discophora because of the microorganism's capability to deposit biomineralized manganese oxides on the electrode. Biomineralized manganese oxides are superior to oxygen when used as a cathodic reactant. In the anodic compartment of most of the fuel cells we oxidized glucose using Klebsiella pneumoniae. In one fuel cell we used Desulfovibrio desulfuricans, a sulfate reducing bacteria. Electrons released in the anodic compartment, ...; Download File | View full details

Comprehensive Transcriptional Profiling of γδ T cells: Author: Graff, Jill Christin; Date: 2005-12-15; Program: Veterinary Molecular Biology; Abstract: γδ T cells have been conserved since the adaptive immune system arose, yet their importance is still unclear. In an attempt to compensate for the lack of a broad knowledge-base of γδ T cells across species, global analyses of γδ T cell transcriptomes have been performed using serial analysis of gene expression (SAGE). Twelve new SAGE libraries were generated from the following bovine lymphocyte populations: magnetic bead-sorted blood γδ T cells, spleen γδ T cells and enr...; Download File | View full details

Study of Praseodymium Strontium Manganite for the Potential use as a Solid Oxide Fuel cell Cathode: Author: Pfluge, Matthew Edward; Date: 2005-05-15; Program: Chemical Engineering; Abstract: Extensive research has been performed on solid oxide fuel cell cathodes. These cathodes must be stable in the oxidation environment and have sufficient electrical conductivity and catalytic activity for the oxidant gas reaction at the appropriate operating temperature. Also, the cathode must be chemically and thermally compatible with the other cell components at room temperature, operating temperatures, and higher fabrication temperatures. Praseodymium strontium manganite (PSM) has shown promising electrical properties with respect to ideal properties of cathodes in solid oxide fuel cells. Va...; Download File | View full details

Sympathetic Ganglia Formation in the Chick Peripheral Nervous System: Author: Kasemeier-Kulesa, Jennifer Caroline; Date: 2005-12-15; Program: Neuroscience; Abstract: The neural crest is a unique population of pluripotent cells that are crucial in vertebrate embryogenesis. In the trunk, NCCs migrate along a ventromedial pathway give rise to the dorsal root ganglia or the sympathetic ganglia (SG), or follow a dorsolateral pathway and give rise to melanocytes. Intriguingly, NCCs following the ventromedial pathway migrate in a metameric pattern through the rostral half somite and avoid the caudal somite and this is thought to dictate the metameric pattern of the SG. Static analyses have characterized the development of these structures, but timelapse imaging o...; Download File | View full details

A Non-Autonomous Bursting Model for Neurons: Author: Latulippe, Joe Jean-Marc; Date: 2007-05-15; Program: Mathematics; Abstract: Certain mammalian visual neurons exhibit On and Off responses when given a light stimulus. In addition to these responses, [51] showed that for retinal ganglion cells, the neuron will also exhibit a Mixed response when given two simultaneous stimuli in different regions of the cell's receptive field. This Mixed response is a nonlinear combination of the On and Off responses. In this dissertation, a single cell model which can reproduce On, Off, and Mixed responses is developed and examined using leading order analyses and averaging. This model is developed from a current balance equation which...; Download File | View full details

Molecular and Functional Characterization of Bovine C5a Receptor: Author: Nemali, Sailasree; Date: 2006-05-15; Program: Veterinary Molecular Biology; Abstract: Anaphylatoxin C5a is an important chemotactic factor for bovine neutrophils, and is the earliest inflammatory agent formed during bovine mastitis. Bovine neutrophils respond to C5a and its truncated form C5a des arg with similar affinities unlike human neutrophils. Therefore, to test the hypothesis that the bovine C5a receptor structure and signaling differ from that of the human C5a receptor, we cloned and analyzed the bovine C5a receptor. In the present investigation, the bovine C5a receptor encoding cDNA from bovine bone marrow was cloned and the recombinant C5a receptor protein was express...; Download File | View full details

Environmental and genetic factors leading to Mycobacterium Avium biofilm formation: Author: Geier, Henriette; Date: 2008-05-15; Program: Microbiology; Abstract: This dissertation investigated the role of environmental and genetic factors that lead to biofilm formation by the environmental and waterborne pathogen Mycobacterium avium. The bacterium causes respiratory and also cutaneous disease predominantly in immunocompromised patients, but infection also occurs in otherwise healthy individuals. M. avium has been frequently isolated from drinking water and it has been shown that the bacterium forms biofilms in drinking water systems. Biofilms show enhanced resistance to antibiotics and disinfectants and therefore are difficult to combat. Biofilm format...; Download File | View full details

Theoretical Investigation of Biofilm Detachment and Protection from Killing using a Bacterium Level Automata Model: Author: Hunt, Stephen Michael; Date: 2004-08-15; Program: Engineering; Abstract: This dissertation presents a three-dimensional dynamic, stochastic computer model of biofilm development, BacLAB, created to theoretically explore conjectures associated with biofilms. BacLAB simulates the life cycle of a biofilm by mimicking the physical and biological behavior of a system with a simple set of experimentally determined "rules" applied to the smallest possible biofilm unit (the cell). These rules, however, lead to patterns on a larger scale. Much as bacterial cells organize themselves in a biofilm as a response to individual spatial conditions, the resulting model st...; Download File | View full details

Identification of Novel Virulence Factors and Mechanisms of Pathogenesis from the Sexually Transmitted Protozoan Tritrichomonas foetus: Author: Higgins, Melanie Rae; Date: 2006-05-15; Program: Veterinary Molecular Biology; Abstract: Tritrichomonas foetus (T. foetus) is the cause of trichomoniasis in cattle. Little is known regarding the basis of virulence in this parasite. Early host-parasite interactions most likely affect the ability of the parasite to colonize the female reproductive tract. These early interactions shape the course of disease and ultimately control the outcome of pathogenesis. The aim of the studies herein is to provide insight into the factors that alter the progression of trichomoniasis. We examined how environmental stress and estradiol treatment affect pathogenesis of trichomoniasis. Acute T. foetu...; Download File | View full details

Loss of the Murine TATA-Binding Protein N Terminus Leads to Placental Labyrinth Defects but not Maternal Adaptive Immune Responses: Author: Sealey, Amy Lynn; Date: 2007-05-15; Program: Veterinary Molecular Biology; Abstract: The TATA-binding protein (TBP) is a component of the basal transcription machinery. The TBP C-terminal core is conserved in all eukaryotes, but the N terminal region is shared between vertebrates. To study this, we generated a mouse line lacking 111 of the 135 amino acids of the vertebrate-specific sequence. The mutant tbp allele was designated tbpΔN, and the majority of homozygous mutants, tbpΔN/ΔN, died at midgestation due to defects in the placenta. Previous studies in our laboratory showed that tbpΔN/ΔN fetuses survived the midgestational crisis if the mo...; Download File | View full details

View next 25 results

Back to search page

print-friendly page | mobile-friendly page