Engineering Commons^™

Design And Fabrication Of Chemiresistor Typemicro/Nano Hydrogen Gas Sensors Usinginterdigitated Electrodes, Peng Zhang

Electronic Theses and Dissertations

Hydrogen sensors have obtained increased interest with the widened application of hydrogen energy in recent years. Among them, various chemiresistor based hydrogen sensors have been studied due to their relatively simple structure and well-established detection mechanism. The recent progress in micro/nanotechnology has accelerated the development of small-scale chemical sensors. In this work, MEMS (Micro-Electro-Mechanical Systems) sensor platforms with interdigitated electrodes have been designed and fabricated. Integrating indium doped tin dioxide nanoparticles, these hydrogen sensors showed improved sensor characteristics such as sensitivity, response and selectivity at room temperature. Design parameters of interdigitated electrodes have been studied in association with sensor characteristics. …

Meshless Hemodynamics Modeling And Evolutionary Shape Optimization Of Bypass Grafts Anastomoses, Zaher El Zahab

Electronic Theses and Dissertations

Objectives: The main objective of the current dissertation is to establish a formal shape optimization procedure for a given bypass grafts end-to-side distal anastomosis (ETSDA). The motivation behind this dissertation is that most of the previous ETSDA shape optimization research activities cited in the literature relied on direct optimization approaches that do not guaranty accurate optimization results. Three different ETSDA models are considered herein: The conventional, the Miller cuff, and the hood models. Materials and Methods: The ETSDA shape optimization is driven by three computational objects: a localized collocation meshless method (LCMM) solver, an automated geometry pre-processor, and a genetic-algorithm-based …

Thermal Modeling And Laser Beam Shaping For Microvias Drilling In High Density Packaging, Chong Zhang

Electronic Theses and Dissertations

Laser drilling of microvias for organic packaging applications is studied in present research. Thermal model is essential to understand the laser-materials interactions and to control laser drilling of blind micro holes through polymeric dielectrics in multilayer electronic substrates. In order to understand the profile of the drilling front irradiated with different laser beam profiles, a transient heat conduction model including vaporization parameters is constructed. The absorption length in the dielectric is also considered in this model. Therefore, the volumetric heating source criteria are applied in the model and the equations are solved analytically. The microvia drilling speed, temperature distribution in …

Methane And Dimethyl Ether Oxidation At Elevated Temperatures And Pressure, Christopher Zinner

Electronic Theses and Dissertations

Autoignition and oxidation of two Methane (CH4) and Dimethyl Ether (CH3OCH3 or DME) mixtures in air were studied in shock tubes over a wide range of equivalence ratios at elevated temperatures and pressures. These experiments were conducted in the reflected shock region with pressures ranging from 0.8 to 35.7 atmospheres, temperatures ranging from 913 to 1650 K, and equivalence ratios of 2.0, 1.0, 0.5, and 0.3. Ignition delay times were obtained from shock-tube endwall pressure traces for fuel mixtures of CH4/CH3OCH3 in ratios of 80/20 percent volume and 60/40 percent volume, respectively. Close examination of the data revealed that energy …

Water Footprint Of Aviation Fuel Synthesis By The Fischer Tropsch Process Using Sugar Cane Waste & Landfill Gas As Feedstocks, Slim Menzli

Electronic Theses and Dissertations

The recent spikes in oil prices have spurred an already bullish demand on biofuels as a source of alternative energy. However, the unprecedented price records set simultaneously by staple food have raised high concerns about potential impacts of biofuels on the global agricultural landscape as fuel and food markets are being inextricably coupled. The revival of interest in the Fischer-Tropsch (FT) process comes into full force since it offers a promising way to produce carbon-neutral liquid fuels which are readily usable with today's existing infrastructure. The FT synthesis offers the possibility of using crop waste as feedstock instead of the …

Design And Experimental Study Of An Integrated Vapor Chamber -" Thermal Energy Storage System, Krishna Kota

Electronic Theses and Dissertations

Future defense, aerospace and automotive technologies involve electronic systems that release high pulsed waste heat like during high power microwave and laser diode applications in tactical and combat aircraft, and electrical and electronic systems in hybrid electric vehicles, which will require the development of an efficient thermal management system. A key design issue is the need for fast charging so as not to overheat the key components. The goal of this work is to study the fabrication and technology implementation feasibility of a novel high energy storage, high heat flux passive heat sink. Key focus is to verify by theory …

A Customer Programmable Microfluidic System, Miao Liu

Electronic Theses and Dissertations

Microfluidics is both a science and a technology offering great and perhaps even revolutionary capabilities to impact the society in the future. However, due to the scaling effects there are unknown phenomena and technology barriers about fluidics in microchannel, material properties in microscale and interactions with fluids are still missing. A systematic investigation has been performed aiming to develop "A Customer Programmable Microfluidic System". This innovative Polydimethylsiloxane (PDMS)-based microfluidic system provides a bio-compatible platform for bio-analysis systems such as Lab-on-a-chip, micro-total-analysis system and biosensors as well as the applications such as micromirrors. The system consists of an array of microfluidic …

An Improved Thermoregulatory Model For Cooling Garment Applications With Transient Metabolic Rates, Johan Westin

Electronic Theses and Dissertations

Current state-of-the-art thermoregulatory models do not predict body temperatures with the accuracies that are required for the development of automatic cooling control in liquid cooling garment (LCG) systems. Automatic cooling control would be beneficial in a variety of space, aviation, military, and industrial environments for optimizing cooling efficiency, for making LCGs as portable and practical as possible, for alleviating the individual from manual cooling control, and for improving thermal comfort and cognitive performance. In this study, we adopt the Fiala thermoregulatory model, which has previously demonstrated state-of-the-art predictive abilities in air environments, for use in LCG environments. We validate the …

Using Show Homes (And Sponsorships) To Persuade Commissioning Relevancy And Factory Crafted High Performance Modular Homes, Florida Solar Energy Center, Stephanie Thomas-Rees

FSEC Energy Research Center®

The International Builders' Show (IBS) sponsored by the National Association of Home Builders is a venue attracting over 100,000 builders and building related professionals every year. The increased attendances each year improves the educational sessions, vendor participation and "live" home construction demonstrations. The "live" home demonstrations are a great opportunity to integrate high performance construction and commissioning strategies into the marketplace to validate and distinguish products and the show home builders. At this past year's IBS show in February, Palm Harbor Homes built the GenX home that included an installed and operational 4.08kWp photovoltaic system with inverter and back up …

Deploying Mobile Pv Emergency Power System In A Disaster, Florida Solar Energy Center, William Young

FSEC Energy Research Center®

Disasters can be as destructive as Hurricane Katrina, leaving several hundred-thousand people homeless, or as minor as an afternoon thunderstorm that brings down local power lines to your home. After a disaster, utility services may be damaged or destroyed, leaving people without water, sanitation, communication and electricity. In response to a disaster, first responders are deployed with life supporting resources, such as water, food, and medical supplies. Energy resources are often lacking, making recovery efforts difficult in our high-tech world of cell phones, television, computers, refrigerators and many other electronic devices.

After a disaster, the long time tradition used to …