Digital Commons Network^™

Basic Capillary Microfluidic Chip And Highly Sensitive Optical Detector For Point Of Care Application, Mingjin Yao

Doctoral Dissertations

A cost-effective and highly sensitive portable diagnostic device is needed to enable much more widespread monitoring of health conditions in disease prevention, detection, and control. Miniaturized and easy-to-operate devices can reduce the inherent costs and inefficiencies associated with healthcare testing in central laboratories. Hence, clinicians are beginning to use point of care (POC) testing and flexible clinical chemistry testing devices which are beneficial for the patient.

In our work, a low-cost and simple autonomous microfluidic device for biochemical detection was developed. The pumpless capillary system with capillary stop valves and trigger valves is fabricated on a silicon (Si) wafer and …

Examining The Effects Of Fear Of Failure, Self-Efficacy And Gender Role Conflict In Male And Female Engineering Students, Krista L. Nelson

Doctoral Dissertations

The field of engineering continues to have significantly fewer women engineers than men. Engineering has long been considered to be a male dominated career, with fewer women receiving bachelor's degrees in engineering and gaining employment in the engineering field. The present study was an attempt to determine influencing factors that discourage women from pursuing engineering as an educational and career choice. The current study examined gender role conflict, self-efficacy, and fear of failure as potential factors influencing women's preferences to pursue an engineering degree. Both male and female genders were participants in the research to determine gender differences for these …

Asymmetric Directional Microphone Fittings For Individuals With An Asymmetric Hearing Loss, Jessica White

Doctoral Dissertations

The present study investigated the effects of asymmetric directional microphone fittings on participants' acceptance of background noise and speech understanding in noise abilities. Thirteen adult, bilateral hearing aid users or non-hearing aid users with bilateral asymmetrical sensorineural hearing loss were fit binaurally with four different microphone conditions (i.e., bilateral omnidirectional, asymmetric directional poorer ear, asymmetric directional better ear, and bilateral directional) and monaurally with two microphone conditions (i.e., unilateral directional better ear and unilateral omnidirectional better ear). The amplification used was a pair of Siemens Intuis directional behind-the-ear hearing aids and comply earmolds.

The results indicated speech understanding in noise …

Mathematical Modeling Of Pipeline Features For Robotic Inspection, Yang Gao

Doctoral Dissertations

Underground pipeline systems play an indispensable role in transporting liquids in both developed and developing countries. The associated social and economic cost to repair a pipe upon abrupt failure is often unacceptable. Regular inspection is a preventative action that aims to monitor pipe conditions, catch abnormalities and reduce the chance of undesirable surprises. Robots with CCTV video cameras have been used for decades to inspect pipelines, yielding only qualitative information. It is becoming necessary and preferable for municipalities, project managers and engineers to also quantify the 3-D geometry of underground pipe networks. Existing robots equipped specialized hardware and software algorithms …

Near-Optimal Scheduling And Decision-Making Models For Reactive And Proactive Fault Tolerance Mechanisms, Nichamon Naksinehaboon

Doctoral Dissertations

As High Performance Computing (HPC) systems increase in size to fulfill computational power demand, the chance of failure occurrences dramatically increases, resulting in potentially large amounts of lost computing time. Fault Tolerance (FT) mechanisms aim to mitigate the impact of failure occurrences to the running applications. However, the overhead of FT mechanisms increases proportionally to the HPC systems' size. Therefore, challenges arise in handling the expensive overhead of FT mechanisms while minimizing the large amount of lost computing time due to failure occurrences.

In this dissertation, a near-optimal scheduling model is built to determine when to invoke a hybrid checkpoint …

Fabrication And Characterization Of Hybrid Energy Harvesting Microdevices, Zhongcheng Gong

Doctoral Dissertations

In this dissertation, a hybrid energy harvesting system based on a lead zirconate titanate (PZT) and carbon nanotube film (CNF) cantilever structure has been designed, fabricated and studied. It has the ability to harvest light and thermal radiation energy from ambient energy and convert them to electricity.

The proposed micro-scale energy harvesting device consists of a composite cantilever beam (SU-8/CNF/Pt/PZT/Pt) which is fixed on a silicon based anchor and two electrode pads for wire bonding. The CNF acts as an antenna to receive radiation energy and convert it to heat energy and then transfer to the whole cantilever structure. The …

Failure Prediction For High-Performance Computing Systems, Narate Taerat

Doctoral Dissertations

The failure rate in high-performance computing (HPC) systems continues to escalate as the number of components in these systems increases. This affects the scalability and the performance of parallel applications in large-scale HPC systems. Fault tolerance (FT) mechanisms help mitigating the impact of failures on parallel applications. However, utilizing such mechanisms requires additional overhead. Besides, the overuse of FT mechanisms results in unnecessarily large overhead in the parallel applications. Knowing when and where failures will occur can greatly reduce the excessive overhead. As such, failure prediction is critical in order to effectively utilize FT mechanisms. In addition, it also helps …

The Engineering Design Process As A Model For Stem Curriculum Design, Krystal Sno Corbett

Doctoral Dissertations

Engaging pedagogics have been proven to be effective in the promotion of deep learning for science, technology, engineering, and mathematics (STEM) students. In many cases, academic institutions have shown a desire to improve education by implementing more engaging techniques in the classroom. The research framework established in this dissertation has been governed by the axiom that students should obtain a deep understanding of fundamental topics while being motivated to learn through engaging techniques. This research lays a foundation for future analysis and modeling of the curriculum design process where specific educational research questions can be considered using standard techniques. Further, …

The Search For An Optimal Means Of Determining The Minmax Control Parameter Using Sensitivity Analysis, John Teye Brown

Doctoral Dissertations

The use of computational methods for design and simulation of control systems allows for a cost-effective trial and error approach. In this work, we are concerned with the robust, real-time control of physical systems whose state space is infinite-dimensional. Such systems are known as Distributed Parameter Systems (DPS). A body whose state is heterogeneous is a distributed parameter. In particular, this work focuses on DPS systems that are governed by linear Partial Differential Equations, such as the heat equation. We specifically focus on the MinMax controller, which is regarded as being a very robust controller. The mathematical formulation of the …

A Failure Index For High Performance Computing Applications, Clayton F. Chandler

Doctoral Dissertations

This dissertation introduces a new metric in the area of High Performance Computing (HPC) application reliability and performance modeling. Derived via the time-dependent implementation of an existing inequality measure, the Failure index (FI) generates a coefficient representing the level of volatility for the failures incurred by an application running on a given HPC system in a given time interval. This coefficient presents a normalized cross-system representation of the failure volatility of applications running on failure-rich HPC platforms. Further, the origin and ramifications of application failures are investigated, from which certain mathematical conclusions yield greater insight into the behavior of these …

The Effect Of Distinguished Educators On Academic Gain Of Louisiana Academically Unacceptable Schools, Ruby C. Scroggins

Doctoral Dissertations

The purpose of this study was to examine the degree of academic growth of Academically Unacceptable schools in Louisiana which have been assigned a Distinguished Educator. Distinguished Educators are external change agents who are placed in Academically Unacceptable schools in Louisiana. The data were generated from the Louisiana Department of Education. The study investigated if English Language Arts (ELA) and mathematics scores significantly increased in schools which were assigned a Distinguished Educator. School Performance Scores for third, fourth, and fifth grades were examined to determine growth, as well. The ex post factodesign study consisted of different school configurations which …

Investigation Of Wellbore Stability In A North Sea Field Development, Steven Austin Hilgedick

Doctoral Dissertations

"Planning drilling operations is key to the development of oil and natural gas fields. As part of well design, wellbore stability and pore pressure analysis are main factors in determining the safe operating window for selecting mud density. The motivation for this research was to conduct wellbore stability based on exploration wells as basis for planning new offshore field developments with deviated and horizontal wells. A second objective was to investigate the use of a probabilistic approach to wellbore stability, and compare it to the conventional deterministic methods, in order to evaluate the value of including a probabilistic approach to …

The Risk Mitigation Strategy Taxonomy And Generated Risk Event Effect Neutralization Method, Daniel A. Krus

Doctoral Dissertations

"In the design of new products and systems, the mitigation of potential failures is very important. The sooner in a product's design mitigation can be performed, the lower the cost and easier to implement those mitigations become. However, currently, most mitigations strategies rely on the expertise of the engineers designing a product, and while models and for failure modes do exist to help, there are no guidelines for performing product changes to reduce risk. To help alleviate this, the risk mitigation strategy taxonomy is created from an empirical collection of mitigation strategies used in industry for failure mitigation, creating a …

Cavity Ring Down: Construction, Validation And Experiments Measuring The Optical Extinction Of Pure Clays And Their Mixtures With Salts And Carboxylic Acids Under A Range Of Atmospherically Relevant Conditions, Alexis Rae Attwood

Doctoral Dissertations

Aerosols interact directly with solar radiation by scattering and absorbing incident light to affect the Earth's climate system. Models indicate that aerosols cool the Earth counterbalancing greenhouse gases, but contribute the largest uncertainty to anthropogenic effects on climate. To address these uncertainties, a cavity ring down spectrometer (CRD) was built and performance tests were conducted to validate its capabilities for measuring optical properties of laboratory generated, atmospherically relevant aerosols over a range of conditions. The CRD provides an absolute and unbiased in situ measurement of total extinction and can reduce uncertainties associated with aerosols having unusual chemical and physical properties. …

Mechanism Of Sps Acceleration In A Peg Containing Copper Plating Bath, Ashleigh Kreider

Doctoral Dissertations

Deposition of copper in Through Silicon Vias (TSVs) is achieved by addition of organic compounds, which act as suppressors and accelerants to copper electroplating solutions. The focus of this study is on the acceleration effect of bis-(3-sodiumsulfopropyl) disulfide (SPS) which is believed to go through an electrochemical reaction to form sodium 3-mercapto-1-propanesulfonate (MPS), the effective accelerant. The accelerant is believed to operate by forcing the suppressor off the copper surface through competitive adsorption. The kinetics of MPS adsorption onto copper was studied by addition of MPS to solutions containing the suppressor molecule, polyethylene glycol (PEG), under constant overpotential and measurement …

Liquefaction And Ring Shear Device, Julian A. Sandoval

Doctoral Dissertations

Liquefaction flow slides triggered by earthquakes or heavy rainfall in saturated granular soils have produced great damage in landslide-prone areas worldwide. A major aspect that needs more study is how the 'residual strength' remaining in the liquefied material evolves at the high strain levels imposed as the slide progresses. Strength of liquefied granular soils is usually studied in the lab by means of the triaxial test, since the strains required to trigger liquefaction are low, compared with those observed after it has been produced. More sophisticated devices are necessary in order to apply the high strains and shear strain rates …

The Role Of Red-Backed Salamanders In Ecosystems, Daniel J. Hocking

Doctoral Dissertations

Ecosystems provide a vast array of services that benefit human societies, which can be divided into provisioning, regulating, cultural, and supporting services. Amphibians provide provisioning services in the form of food and use in medical advances. As one of the major vertebrate groups, amphibians also play an important part in cultures throughout the world. Finally, amphibians can be extremely abundant and play important roles in ecosystem supporting services, including altering both physical structure and ecosystem functions. In aquatic systems, tadpoles can alter sedimentation, water clarity, and filamentous algae growth. Additionally, amphibians affect ecosystem functions, including nutrient cycling, decomposition, and primary …

Cusp Ion Structures And Their Relation To Magnetopause Processes, Hyun Ju Connor

Doctoral Dissertations

Dispersed ion structures observed near the magnetosphere cusps have long been used to infer locations and properties of reconnection at the Earth's magnetopause. However, observations are often difficult to interpret since spacecraft move relative to a cusp ion structure, creating temporal/spatial ambiguity in the observations. Models of cusp ion structures are also limited to the cases during stable solar wind and IMF because empirical models are used to obtain the Earth's electromagnetic fields. In this dissertation, we develop a dynamic model of cusp ion structures usable for non-steady solar wind and IMF cases by using the Liouville Theorem Particle Tracer …

Processes Influencing Visual Awareness During Motion-Induced Blindness, Erika T. Wells

Doctoral Dissertations

Visual illusions, such as motion-induced blindness, arise when the visual system, balancing speed and efficiency, summarizes the information it receives to form a percept. Motion-induced blindness (MIB) is characterized as the disappearance of a salient target when surrounded by a moving mask. Efforts to determine the mechanism have focused on the role of target characteristics on perceived disappearance by a coherently moving mask. In this dissertation, I take another approach, paying specific attention to the role of motion characteristics of the mask.

In Experiments 1, 2, 3, and 4, I investigate whether the property of common fate influences target disappearance …

Observational Studies Of Scatterometer Ocean Vector Winds In The Presence Of Dynamic Air-Sea Interactions, Amanda Michael Plagge

Doctoral Dissertations

Ocean vector wind measurements produced by satellite scatterometers are used in many applications across many disciplines, from forcing ocean circulation models and improving weather forecasts, to aiding in rescue operations and helping marine management services, and even mapping energy resources. However, a scatterometer does not in fact measure wind directly; received radar backscatter is proportional to the roughness of the ocean's surface, which is primarily modified by wind speed and direction. As scatterometry has evolved in recent decades, highly calibrated geophysical model functions have been designed to transform this received backscatter into vector winds. Because these products are used in …

Comparative Systems Analysis Of Thermochemical And Biochemical Recycling Of Organic Waste Towards Industrial Feedstocks, Philip Nuss

Doctoral Dissertations

Shifting the resource base for chemical and energy production from fossil feedstocks to renewable raw materials is seen by many as one of the key strategies towards sustainable development. The utilization of biomass for the production of fuels and materials has been proposed as an alternative to the petroleum-based industry. Current research and policy initiatives focus mainly on the utilization of lignocellulose biomass, originating from agriculture and forestry, as second generation feedstocks for the production of biofuels and electricity. These activities act on the assumption that significant amounts of biomass for non-food purposes are available.

However, given a certain productivity …

The Impact Of Multilayer Periodicity On Texture, Morphology, Chemical Stability And Machining Performance Of Titanium Aluminum Nitride/Chromium Nitride Thin Films, Dale Andrew Delisle

Doctoral Dissertations

Multilayer thin films of TiAlN/CrN were deposited at varying bilayer periods (lambda = 2, 4, 8 and 16 nm), along with a co-deposited (TiAlCr)N film and constituent TiAlN and CrN films, on both [111] silicon substrates and WC-4wt% Co inserts with an ISO SPGN 120308 geometry. The effects of periodicity on grain structure, texture, surface morphology, and roughness were examined, with characterization performed using electron microscopy, atomic force microscopy and x-ray diffraction analysis. An in-air constant temperature oxidation study was also performed at 650 thru 1050°C with stacked XRD line profiles and SEM used to identify the onset and extent …

On Wavelet-Based Testing For Serial Correlation Of Unknown Form Using Fan's Adaptive Neyman Method, Shan Yao

Doctoral Dissertations

Test procedures for serial correlation of unknown form with wavelet methods are investigated in this dissertation. The new wavelet-based consistent test is motivated using Fan's (1996) canonical multivariate normal hypothesis testing model. In our framework, the test statistic relies on empirical wavelet coefficients of a wavelet-based spectral density estimator. We advocate the choice of the simple Haar wavelet function, since evidence demonstrates that the choice of the wavelet function is not critical. Under the null hypothesis of no serial correlation, the asymptotic distribution of a vector of empirical wavelet coefficients is derived, which is the multivariate normal distribution in the …

Examining Celestial Polarization With The Gamma Ray Polarimeter Experiment (Grape), Taylor Pyne Connor

Doctoral Dissertations

This dissertation describes the development of the Gamma Ray Polarimeter Experiment (GRAPE), which is designed to measure the polarization of astronomical sources from 50 keV to 500 keV, and presents the Crab observation results from the successful 2011 balloon campaign. The successful balloon flight of this instrument took place on September 23rd and 24th, at Fort Sumner, New Mexico (Flight N624). The instrument was at float altitude for twenty-six hours. The Crab Nebula/Pulsar, Cygnus X-1, and the Sun were observed within the collimated field of view of GRAPE. A polarization fraction of 55.3% +/- 35.6% and a polarization position angle …

The Use Of Multibeam And Split-Beam Echo Sounders For Assessing Biomass And Distribution Of Spring-Spawning Atlantic Cod In The Gulf Of Maine, Christopher William Damon Gurshin

Doctoral Dissertations

This research focused on advancing the application of split-beam and multibeam echo sounding to remotely locate and describe spatial distribution, and to provide a relative measure of abundance of the spring-spawning Atlantic cod (Gadus morhua) in the western Gulf of Maine. Specifically, the main objectives of this research were 1) to test the feasibility of a multibeam echo sounder to detect changes in volume backscatter proportional to incrementally decreasing quantities of cod held in a submerged cage, and to compare results to a split-beam echo sounder; 2) to describe the spatio-temporal distribution and estimate biomass of spring-spawning cod in the …

The Historical Fisheries In The Mediterranean Sea: A Reconstruction Of Trawl Gear, Effort And Trends In Demersal Fish Stocks, Giacomo Chato Osio

Doctoral Dissertations

An extensive search of historical data sources and publications has been carried out in different countries of the Mediterranean. This lead to the construction of the largest compilation of historical fisheries information existing in the Mediterranean region. The goal first here was to quantify historical trawling effort. This shows that Mediterranean demersal communities underwent a much longer and more systematic exploitation than previously thought, very likely the longest known exploitation by means of trawls in Europe and North America. Analysis of the data available for the Catalonian, Italian and French areas showed a clearly emerging pattern: fishing capacity increased in …

Essays On Motor Fuel Taxation And Price Dynamics In The European Union, Aliya Sassi

Doctoral Dissertations

When the economic literature refers to characteristics of the motor fuel market in the EU, one has to be cautious in comparing indicators across time and space because of the ongoing enlargement of the Union. This dissertation contributes to a limited empirical literature on motor fuel fiscal competition and discussions on fuel tourism and fiscal policy coordination in Europe. The first essay provides an overview of the EU market from 1994 to 2010 for four major motor fuels and its evolution at every stage of EU expansion. It examines changes in the characteristics and taxation rates of the EU representative …

Fairness In A Data Center, Mikkel Hagen

Doctoral Dissertations

Existing data centers utilize several networking technologies in order to handle the performance requirements of different workloads. Maintaining diverse networking technologies increases complexity and is not cost effective. This results in the current trend to converge all traffic into a single networking fabric. Ethernet is both cost-effective and ubiquitous, and as such it has been chosen as the technology of choice for the converged fabric. However, traditional Ethernet does not satisfy the needs of all traffic workloads, for the most part, due to its lossy nature and, therefore, has to be enhanced to allow for full convergence. The resulting technology, …

Morphological Study Of Composite Latex Particles And Water Interaction With Polymer Chains, Bo Jiang

Doctoral Dissertations

The primary purpose of this research was the morphological study of composite polymer (2 or more) nano-particles in an aqueous dispersed system. This included synthesis, characterization and mathematical/numerical modeling. For a composite latex particle, the morphology can play an important role in determining the final application properties, and the structure depends on many factors which are active during and after polymerization. Among these are the penetration of oligomeric chains into the latex particles, mixing of the two composite polymers, and eventual phase separation of such mixtures. These actions depend upon the materials used in the polymerization and the process by …

Interaction Between The Coastal Ocean And The Estuarine Systems, Shivanesh Arvinda Rao

Doctoral Dissertations

Fluctuating winds change the interaction between an estuary and its adjacent coastal ocean. This change in the interaction determines how the wind-induced changes in the estuary influence the near-shore coastal ocean and vice-versa.

The first chapter examines the water properties in the near-shore coastal region close to estuaries after coastal upwelling. In regions where the time-integrated upwelling and down-welling wind stresses are comparable, there exists a region in the direction of a coastal Kevin wave propagation from an estuary, where the arrival of the plume in the near-shore region prevents the upwelled front from returning to the coast. The weakened …