Engineering Commons^™

High Impedance Arc Fault Detection In A Manhole Environment., Thomas Arthur Cooke

Electronic Theses and Dissertations

The scope of this thesis was to develop a prototype high-impedance arc detection system that a utility worker could use as an early warning system while working in a manhole environment. As part of this system sensors and algorithms were developed to increase the sensitivity of detecting an arc while ignoring loads that can give false positive signatures for arcing. The latest technology was used to repeat measurements performed in previous research from decades ago that lacked in sampling speed and amplitude resolution. Several types of arcs were produced and analyzed so to establish a library of various waveform and …

Studies On The Preparation And Luminescence Properties Of Cadmium Selenide Quantum Dots, Their Immobilization, And Applications., Travis Justin Heath

Electronic Theses and Dissertations

Quantum dots are semiconductive particles whose properties are highly influenced by the presence of at least one electron. Cadmium selenide quantum dots were synthesized via colloidal synthesis. Contrary to previous preparations, more focus was placed on the temperature rather than the duration of time at which they form. A series of colored solutions were obtained because the excited quantum dots of various sizes emitted specific wavelengths of light. The emission spectra showed that the temperature-dependent quantum dots were successfully synthesized. The quantum dots were also immobilized on various surfaces, and the luminescence properties were examined. The quantum dots that were …

New Handheld Emissions Detector For Pinpointing The Location Of Inadvertently Energized Objects In Urban Environments., Kermit O. Phipps

Electronic Theses and Dissertations

The power distribution infrastructure in the United States is deteriorating at a rapid rate exposing infrastructure wiring and creating potential shock hazards. Periodic road and sidewalk maintenance projects can also expose wiring and create energized objects. In urban settings inadvertently energized objects include: lamp posts, bus shelters, metal street curbs, sign posts, transformer vaults, and manhole covers as well as concrete and asphalt pavement. Every year electric shocks occur when people and domestic animals (such as dogs and cats) make incidental contact with these energized objects. In very rare cases the shocks from these contacts are lethal. Through current personal …

Mobile Map Browsers: Anticipated User Interaction For Data Pre-Fetching, Benjamin T. Weber

Electronic Theses and Dissertations

When browsing a graphical display of geospatial data on mobile devices, users typically change the displayed maps by panning, zooming in and out, or rotating the device. Limited storage space on mobile devices and slow wireless communications, however, impede the performance of these operations. To overcome the bottleneck that all map data to be displayed on the mobile device need to be downloaded on demand, this thesis investigates how anticipated user interactions affect intelligent pre-fetching so that an on-demand download session is extended incrementally. User interaction is defined as a set of map operations that each have corresponding effects on …

Reconode: Towards An Autonomous Multi-Robot Team Agent For Usar, Kang Li

Electronic Theses and Dissertations

Urban search and rescue (USAR) robots can benefit from small size as it facilitates movement in cramped quarters. Yet, small size limits actuator power, sensor payloads, computational capacity and battery life. We are alleviating these issues by developing the hardware and software infrastructure for high performance, heterogeneous, dynamically-reconfigurable miniature USAR robots, as well as a host of other relevant applications. In this thesis, a generic modular embedded system architecture based on the RecoNode multiprocessor is proposed, which consists of a set of hardware and software modules that can be configured to construct various types of robot systems for dynamic and …

A Safeguards Design Strategy For Domestic Nuclear Materials Processing Facilities., Jonathan Long

Electronic Theses and Dissertations

The outdated and oversized nuclear manufacturing complex within the United States requires its transformation into a smaller, safe, and secure enterprise. Health and safety risks, environmental concerns, and the end of the Cold War have all contributed to this necessity. The events of September 11, 2001, emphasized the protection requirements for nuclear materials within the U.S. as well as abroad.

Current Nuclear Safeguards regulations contain minimal prescriptive requirements relating to the design of new production facilities. Project management and engineering design guides require that design documents contain specific and measureable statements relating to systems requirements. The systems engineering process evaluates …

An Active Study Of A Roller Coaster Project In Asia., Robert Leamon Bridges

Electronic Theses and Dissertations

A roller coaster manufacturer became aware that improperly heat treated track couplings were sent to a construction site for assembly. Concerns were that suspect couplings might not meet the engineering specifications and could be vulnerable to sudden failure. A testing company in Oak Ridge, TN that specializes in in-situ and laboratory mechanical testing was contacted by the manufacturer for help in this endeavor. The construction company elected to enlist a local testing firm to perform field tests on the components instead of the company in Oak Ridge. The test methods used are incapable of providing quantitative results that could be …

Application Of Temporal Difference Learning To The Game Of Snake., Christopher Lockhart

Electronic Theses and Dissertations

The game of Snake has been selected to provide a unique application of the TD( ) algorithm as proposed by Sutton. A reinforcement learning technique for producing computer controlled players is documented. Using value function approximation with multilayer artificial neural networks and the actor-critic architecture, computer players capable of playing the game of Snake can be created. The adaptation to the standard neural network backpropagation procedure will be documented. Not only does the proposed technique provide reasonable player performance, its application is unique; this approach to Snake has never been documented. By performing sets of trials, the performance of the …

Anaerobic Fermentation Of Hemicellulose Present In Green Liquor And Hot Water Extracts To Carboxylic Acids, Rakhi Reddy Baddam

Electronic Theses and Dissertations

Wood is composed of cellulose, hemicellulose and lignin. In the paper industry the cellulose fraction is the major resource used in paper production, whereas the hemicellulose and the lignin are usually burned for heat recovery. Recently, wood-derived hemicellulose extracts have received much attention for the production of valuable bioproduct fuels and chemicals. Mixed-culture microbial ecosystems are capable of converting biomass materials, such as wood extracts, into mixtures of carboxylic acids (C1-C7), which can in turn be purified and sold as products, or converted into other organic chemicals through chemical means. The relative concentrations of the acids produced in the fermentations …

Fabrication Of Integrated Optofluidic Circuits In Chalcogenide Glass Using Femtosecond Laser Direct Writing, Troy P. Anderson

Electronic Theses and Dissertations

Femtosecond laser direct writing (FLDW) is a versatile process that uses focused femtosecond pulses to modify the physical structure of a material, which can result in a shift of optical properties such as the linear and nonlinear refractive index. If the photon energy of the femtosecond pulses lies below the material bandgap, nonlinear absorption rather than linear absorption becomes the dominant mechanism of energy transfer to the material. In this manner, a focused femtosecond pulse train can be used to fabricate functional features such as optical waveguides, diffractive optical elements, or micro-fluidic elements within the volume of a transparent medium. …

Particle Separation Through Taylor-Couette Flow And Dielectrophoretic Trapping, Christopher Paul Bock

Electronic Theses and Dissertations

As the world population approaches seven billion, a greater strain is put on the resources necessary to sustain life. One of the most basic and essential resources is water and while two thirds of the earth is covered by water, the majority is either salt water (oceans and seas) or it is too contaminated to drink. The purpose of this project is to develop a portable device capable of testing whether a specific source of water (i.e. lake, river, well…) is potable. There are numerous filtration techniques that can remove contaminants and make even the dirtiest water clean enough for …

Synthesis, Structure, And Catalytic Properties Of Size-Selected Platinum Nanoparticles, Simon Armando Covone

Electronic Theses and Dissertations

The use of heterogeneous catalysis is well established in chemical synthesis, energy, and environmental engineering applications. Supported Pt nanoparticles have been widely reported to act as catalysts in a vast number of chemical reactions. In this report, the performance of Pt/ZrO2 nanocatalyst for the decomposition of methanol, ethanol, 2-propanol, and 2-butanol is investigated. The potential of each alcohol for the production of H2 and other relevant products in the presence of a catalyst is studied. All the alcohols studied show some decomposition activity below 200°C which increased with increasing temperature. In all cases, high selectivity towards H2 formation is observed. …

Structural Health Monitoring Of A Stadium For Evaluating Human Comfort And Structural Performance, Hasan Sazak

Electronic Theses and Dissertations

Light and rapid constructions as well as considerations such as improved line of sight and increased capacity for modern stadium structures make them vulnerable for vibration serviceability problems. These problems are also observed at convention centers, large shopping malls, concert halls and ballrooms. Especially when the individuals in a crowd are involved in some sort of coordinated motion, this type of loading creates the most potential for high levels of vibration. In order to understand the causes of vibration, vibration levels, service and safety levels, Structural Health Monitoring (SHM) can be implemented to track and evaluate performance of a structure …

The Relevance Of Time-To-Digital Converters To Small Platform Direction Finding Systems, Paul Jeffrey Nelson

Electronic Theses and Dissertations

This thesis explores a Time-Difference-of-Arrival (TDOA) approach to radio direction finding, utilizing picosecond-resolution Time-to-Digital Converters (TDCs). By measuring the relative time of arrival of a pulsed RF signal impinging on an antenna array, direction of arrival (DOA) can be ascertained. This technology enables versatile DOA calculation on platforms only several meters in length, and offers various size, weight, power, and cost advantages when compared to present DF technologies. A short baseline S-band TDOA DF system utilizing TDCs is designed, fabricated, and tested in a laboratory environment. This research suggests that such a DF system based on TDCs provides sufficient accuracy …

Characterization Of Aluminum Doped Zinc Oxide Thin Films For Photovoltaic Applications, Bojanna P. Shantheyanda

Electronic Theses and Dissertations

Growing demand for clean source of energy in the recent years has increased the manufacture of solar cells for converting sun energy directly into electricity. Research has been carried out around the world to make a cheaper and more efficient solar cell technology by employing new architectural designs and developing new materials to serve as light absorbers and charge carriers. Aluminum doped Zinc Oxide thin film, a Transparent conductive Oxides (TCO) is used as a window material in the solar cell these days. Its increased stability in the reduced ambient, less expensive and more abundance make it popular among the …

Correlation Between Preparation Parameters And Properties Of Molybdenum Back Contact Layer For Cigs Thin Film Solar Cells, Eigo Takahashi

Electronic Theses and Dissertations

Molybdenum (Mo) thin film back contact layers for thin film CuIn(1-x)GaxSe2 (CIGS) solar cells were deposited onto soda lime glass substrates using a direct current (DC) planar magnetron sputtering deposition technique. Requirements for the Mo thin film as a back contact layer for CIGS solar cells are various. Sheet resistance, contact resistance to the CIGS absorber, optical reflectance, surface morphology, and adhesion to the glass substrate are the most important properties that the Mo thin film back contact layer must satisfy. Experiments were carried out under various combinations of sputtering power and working gas pressure, for it is well known …

Experimental Studies Of The Heat Transfer Characteristics Of Silica Nanoparticle Water-Based Dispersion In Pool Boiling Using Nichrome Flat Ribbons And Wires, Diane Marie Vazquez

Electronic Theses and Dissertations

This work deals with a study of enhanced critical heat flux (CHF) and burnout heat flux (BHF) in pool boiling of water with suspended silica nanoparticles using ribbon-type and wire heaters. Previously our group and other researchers have reported three-digit percentage increase in critical heat flux in silica nanofluids. This study investigates the effect of various heater surface dimensions and cross-sectional shapes on pool boiling heat transfer characteristics of water and water-based nanofluids. CHF and BHF were analyzed for circular and rectangular cross-section nichrome wires and ribbons of increasing sizes in the range of 0.32mm to 2.38mm width, approaching a …

Mechanical Properties Of Carbon Nanotube/Metal Composites, Ying Sun

Electronic Theses and Dissertations

Carbon nanotubes (CNTs) have captured a great deal of attention worldwide since their discovery in 1991. CNTs are considered to be the stiffest and strongest material due to their perfect atomic arrangement and intrinsic strong in-plane sp 2—sp 2 covalent bonds between carbon atoms. In addition to mechanical properties, CNTs have also shown exceptional chemical, electrical and thermal properties. All these aspects make CNTs promising candidates in the development of novel multi-functional nanocomposites. Utilizing CNTs as fillers to develop advanced nanocomposites still remains a challenge, due to the lack of fundamental understanding of both material processing at the nanometer scale …

Analysis And Optimization Of A Solar Thermal Collector With Integrated Storage, Monica Bonadies

Electronic Theses and Dissertations

Solar energy, a topic popular in the United States during the oil embargo of the 1970’s, has become a relevant topic once more with the current focus on reducing greenhouse emissions. Solar thermal energy in particular has become popular as it uses existing steam turbine technology to produce electricity, with the benefit of using solar energy to produce steam rather than coal or nuclear heat sources. Solar thermal can also be used at lower temperatures to heat water for pools or for residential use. While this energy source has its benefits, it has the problem of being opportunistic – the …

Experimental And Theoretical Approaches To Characterization Of Electronic Nonlinearities In Direct-Gap Semiconductors, Claudiu Cirloganu

Electronic Theses and Dissertations

The general goal of this dissertation is to provide a comprehensive description of the limitations of established theories on bound electronic nonlinearities in direct-gap semiconductors by performing various experiments on wide and narrow bandgap semiconductors along with developing theoretical models. Nondegenerate two-photon absorption (2PA) is studied in several semiconductors showing orders of magnitude enhancement over the degenerate counterpart. In addition, three-photon absorption (3PA) is studied in ZnSe and other semiconductors and a new theory using a Kane 4-band model is developed which fits new data well. Finally, the narrow gap semiconductor InSb is studied with regard to multiphoton absorption, free-carrier …

A Decision Support System Methodology For The Selection Of Rapid Prototyping Technologies For Investment-Cast Gas Turbine Parts, Angela Gallagher

Electronic Theses and Dissertations

In the power generation sector, more specifically, the gas turbine industry, competition has forced the lead time-to-market for product advancements to be more important than ever. For design engineers, this means that product design iterations and final product development must be completed within both critical time windows and budgetary constraints. Therefore, two areas that have received significant attention in the research and in practice are: (1) rapid prototyping technology development, and (2) rapid prototyping technology selection. Rapid prototyping technology selection is the focus of this research. In practice, selecting the rapid prototyping method that is acceptable for a specific design …

Toward A Real-Time Celestial Body Information System, Brian Mitchell Guise

Electronic Theses and Dissertations

The National Aeronautics and Space Administration maintains a challenging schedule of planned and on-going space exploration missions that extend to the outer reaches of our galaxy. New missions represent a huge investment, in terms of actual costs for equipment and support infrastructure, and personnel training. The success of a mission is critical considering both the monetary investment, and for manned missions, the lives which are put at risk. Tragedies involving Challenger, Columbia, Apollo 7, and the near tragedy of Apollo 13 exemplify that space exploration is a dangerous endeavor, posing extreme environmental conditions on both equipment and personnel. NASA, the …

Bit-Rate Aware Reconfigurable Architecture For H.264/Avc Deblocking Filter, Rakan Khraisha

Electronic Theses and Dissertations

In H.264/AVC, DeBlocking Filter (DBF) achieves bit rate savings and it is used to improve visual quality by reducing the presence of blocking artifacts. However, these advantages come at the expense of increasing computational complexity of the DBF due to highly adaptive mode decision and small 4x4 block size. The DBF easily accounts for one third of the computational complexity of the decoder. The computational complexity required for various target applications from mobile to high definition video applications varies significantly. Therefore, it becomes apparent to design efficient architecture to adapt to different requirements. In this work, we exploit the scalability …

Reconfigurable Architecture For H.264/Avc Variable Block Size Motion Estimation Based On Motion Activity And Adaptive Search Range, Sumedha Kodipyaka

Electronic Theses and Dissertations

Motion Estimation (ME) technique plays a key role in the video coding systems to achieve high compression ratios by removing temporal redundancies among video frames. Especially in the newest H.264/AVC video coding standard, ME engine demands large amount of computational capabilities due to its support for wide range of different block sizes for a given macroblock in order to increase accuracy in finding best matching block in the previous frames. We propose scalable architecture for H.264/AVC Variable Block Size (VBS) Motion Estimation with adaptive computing capability to support various search ranges, input video resolutions, and frame rates. Hardware architecture of …

Tuning The Properties Of Nanomaterials As Function Of Surface And Environment, Ajay Karakoti

Electronic Theses and Dissertations

Nanotechnology has shaped the research and development in various disciplines of science and technology by redefining the interdisciplinary research. It has put the materials science at the forefront of technology by allowing the researchers to engineer materials with properties ranging from electronics to biomedical by using materials as diverse as ceramics to just plain carbon. These exceptional properties are achieved by minimizing the dimension of particles in such smaller domains that the boundary between the individual atoms, ions or cluster of particles is very small. This results in a change in conventional properties of particles from continuum physics to quantum …

A Governance Reference Model For Service-Oriented Architecture-Based Common Data Initialization A Case Study Of Military Simulation Federation Systems, Jeremy Thomas Lanman

Electronic Theses and Dissertations

Military simulation and command and control federations have become large, complex distributed systems that integrate with a variety of legacy and current simulations, and real command and control systems locally as well as globally. As these systems continue to become increasingly more complex so does the data that initializes them. This increased complexity has introduced a major problem in data initialization coordination which has been handled by many organizations in various ways. Serviceoriented architecture (SOA) solutions have been introduced to promote easier data interoperability through the use of standards-based reusable services and common infrastructure. However, current SOA-based solutions do not …

A Study Of Factors Contributing To Self-Reported Anomalies In Civil Aviation, Chris Andrzejczak

Electronic Theses and Dissertations

A study investigating what factors are present leading to pilots submitting voluntary anomaly reports regarding their flight performance was conducted. The study employed statistical methods, text mining, clustering, and dimensional reduction techniques in an effort to determine relationships between factors and anomalies. A review of the literature was conducted to determine what factors are contributing to these anomalous incidents, as well as what research exists on human error, its causes, and its management. Data from the NASA Aviation Safety Reporting System (ASRS) was analyzed using traditional statistical methods such as frequencies and multinomial logistic regression. Recently formalized approaches in text …

Application Of Antenna Synthesis And Digital Signal Processing Techniques For Active Millimeter-Wave Imaging Systems, Wilson Ariel Caba

Electronic Theses and Dissertations

Millimeter-wave imaging has gathered attention in recent years for its ability to penetrate clothing, thin layers of soils, and certain construction materials. However, image quality remains a challenge that needs to be addressed. One way of improving image quality is by increasing the dimensions of the collecting aperture. A sparse array can be used to synthesize a larger aperture with a limited set of relatively small detectors. In this research we design, build, and test a test-bed having an active source at 94 GHz and an array of coherent detectors, mounted on arms that extend radially on a rotary table. …

Concentric Layout, A New Scientific Data Layout For Matrix Data Set In Hadoop File System, Lu Cheng

Electronic Theses and Dissertations

The data generated by scientific simulation, sensor, monitor or optical telescope has increased with dramatic speed. In order to analyze the raw data speed and space efficiently, data preprocess operation is needed to achieve better performance in data analysis phase. Current research shows an increasing tread of adopting MapReduce framework for large scale data processing. However, the data access patterns which generally applied to scientific data set are not supported by current MapReduce framework directly. The gap between the requirement from analytics application and the property of MapReduce framework motivates us to provide support for these data access patterns in …

Reactive Control Of Autonomous Dynamical Systems, Jiangmin Chunyu

Electronic Theses and Dissertations

This thesis mainly consists of five independent papers concerning the reactive control design of autonomous mobile robots in the context of target tracking and cooperative formation keeping with obstacle avoidance in the static/dynamic environment. Technical contents of this thesis are divided into three parts. The first part consists of the first two papers, which consider the target-tracking and obstacle avoidance in the static environment. Especially, in the static environment, a fundamental issue of reactive control design is the local minima problem(LMP) inherent in the potential field methods(PFMs). Through introducing a state-dependent planned goal, the first paper proposes a switching control …