Holographic Optical Elements For Visible Light Applications In Photo-Thermo-Refractive Glass, Fedor Kompan

Electronic Theses and Dissertations

This dissertation reports on design and fabrication of various optical elements in Photo-thermo-refractive (PTR) glass. An ability to produce complex holographic optical elements (HOEs) for the visible spectral region appears very beneficial for variety of applications, however, it is limited due to photosensitivity of the glass confined within the UV region. First two parts of this dissertation present two independent approaches to the problem of holographic recording using visible radiation. The first method involves modification of the original PTR glass rendering it photosensitive to radiation in the visible spectral region and, thus, making possible the recording of holograms in PTR …

Third-Order Optical Nonlinearities For Integrated Microwave Photonics Applications, Marcin Malinowski

Electronic Theses and Dissertations

The field of integrated photonics aims at compressing large and environmentally-sensitive optical systems to micron-sized circuits that can be mass-produced through existing semiconductor fabrication facilities. The integration of optical components on single chips is pivotal to the realization of miniature systems with high degree of complexity. Such novel photonic chips find abundant applications in optical communication, spectroscopy and signal processing. This work concentrates on harnessing nonlinear phenomena to this avail. The first part of this dissertation discusses, both from component and system level, the development of a frequency comb source with a semiconductor mode-locked laser at its heart. New nonlinear …

Magnesium-Based Treatment For The Degradation Of Octachlorodibenzofuran And Trinitrotoluene, Amal Mogharbel

Electronic Theses and Dissertations

The aim of the present research is to investigate the efficacy of using ball-milled zero-valent magnesium (ZVMg) with and without activated carbon (AC) for the dechlorination of polychlorinated dibenzofurans. Three different solvent systems are presented here which are ethanol, ethanol/ethyl lactate (90:10), and 2-butoxyethanol. These solvents in combination with ZVMg with and without activated carbon were tested towards the degradation of octachlorodibenzofuran (OCDF, the most highly chlorinated PCDF congener). All the tested systems were very powerful and reductively dechlorinated OCDF to less chlorinated congeners. However, the system of ball-milled ZVMg and ethanol was the only system which converted OCDF and …

Thermo- And Zero-Valent Iron-Activated Persulfate Oxidation Of 3,5,6-Trichloro-2-Pyridinol In An Aquatic System, Roaa Mogharbel

Electronic Theses and Dissertations

The compound 3,5,6-trichloro-2-pyridinol (TCPy), a metabolite of the broad-spectrum organophosphorous insecticide chlorpyrifos, is both more persistent and more water soluble than its parent compound. This difference, which allows TCPy to more readily leach into surface water and groundwater, has led to widespread contamination of TCPy in soils and aquatic environments. In this study, the degradation of TCPy by sulfate radicals was evaluated using zero valent ironactivated persulfate systems and heat activated persulfate system in aqueous media. Response surface methodology coupled with Box-Behnken design was applied in these studies to evaluate the effects of the independent variables on the mineralization of …

Improved System For Fabrication And Characterization Of Nanophotonic Devices By Multi-Photon Lithography, Rashi Sharma

Electronic Theses and Dissertations

A new system for multi-photon lithography (MPL) was developed and used to fabricate three-dimensional (3D) structures with higher aspect ratio, better resolution, improved fidelity, and reduced structural distortion relative to a conventional implementation of MPL. A set of curved waveguides (Rbend = 19 μm, and 38 μm) and straight waveguides (length = 50 μm, Rbend = ∞) were fabricated in an epoxide photopolymer and optically characterized using light having a wavelength in vacuum of λ0 = 2.94 μm. The optical performance of the waveguides was compared to novel spatially-variant photonic crystals (SVPCs) previously studied in the group. The waveguides were …

Lewis Base Promoted Annulations Of Allenoates With 1,4-Naphthoquinones, Nicole Marie Shoup

Electronic Theses and Dissertations

Lewis base promoted cyclization of allenoates with electron deficient olefins open up the possibility to generate more complex organic structures. By generating more complex molecules, we are able to produce new compounds for biomedical and material applications. Both phosphine and amine Lewis bases offer interesting annulations with allenoates resulting in Lu or Morita–Baylis–Hillman type reactions. Once the Lewis base engages with the allenoate there can be several modes of nucleophilic reactivity that allows for the allenic ester to act as a two or three carbon synthon. The allenoate can then react with varying electron deficient olefins generating more complex molecules …

Barrier Graphs And Extremal Questions On Line, Ray, Segment, And Hyperplane Sensor Networks, Kirk Anthony Boyer

Electronic Theses and Dissertations

A sensor network is typically modeled as a collection of spatially distributed objects with the same shape, generally for the purpose of surveilling or protecting areas and locations. In this dissertation we address several questions relating to sensors with linear shapes: line, line segment, and rays in the plane, and hyperplanes in higher dimensions.

First we explore ray sensor networks in the plane, whose resilience is the number of sensors that must be crossed by an agent traveling between two known locations. The coverage of such a network is described by a particular tripartite graph, the barrier graph of the …

Chemometric Applications In Fire Debris Analysis: Likelihood Ratios From Naive Bayes And Frequency Of Component And Pyrolysis Product Occurrence, Anuradha Akmeemana

Electronic Theses and Dissertations

One of the major challenges in fire investigation is the determination of the cause of fire. The fire can be accidental or intentional. The determination of ignitable liquid residue (ILR) from fire debris helps the process and this process is called fire debris analysis in forensic science. This is one of the most complex areas in the field of forensics because of the evaporation of the ILR from the debris and the interference of the substrate matrix with the ILR if present. In the present, the final decisions in fire debris analysis are based on categorical statements and it only …

Performance Evaluation Of Blocking And Non-Blocking Concurrent Queues On Gpus, Hossein Pourmeidani

Electronic Theses and Dissertations

The efficiency of concurrent data structures is crucial to the performance of multi-threaded programs in shared-memory systems. The arbitrary execution of concurrent threads, however, can result in an incorrect behavior of these data structures. Graphics Processing Units (GPUs) have appeared as a powerful platform for high-performance computing. As regular data-parallel computations are straightforward to implement on traditional CPU architectures, it is challenging to implement them in a SIMD environment in the presence of thousands of active threads on GPU architectures. In this thesis, we implement a concurrent queue data structure and evaluate its performance on GPUs to understand how it …

An Approach To Semi-Autonomous Indoor Drone System: Software Architecture And Integration Testing, Shobhan Singh

Electronic Theses and Dissertations

To address these problems, we establish a semi-autonomous functionality by removing the RC transmitter, and remotely connecting the Drone System to track status and executing user-based input commands. In order to resolve the limitation in hardware connections on the Flight Controller, we integrated the sonar sensor into a companion computer, from where the data is continuously fed to an embedded system through MAVLink (Micro Aerial Vehicle Link) network communication protocol. In this study, we also implemented a modular architecture which enables scalable integration of sensor modules into the Drone System to streamline the process of development, deployment, testing and debugging.

Ni And Au Transition Metal Complexes In The Photocatalytic Co2 Reduction Reaction, Shakeyia Davis

Electronic Theses and Dissertations

The production of renewable fuels by the conversion of solar energy into chemical energy is a challenge. Photocatalytic and electrocatalytic conversion of CO2 to usable fuel precursors are approaches to overcoming this challenge. The two-electron reduction of carbon dioxide to carbon monoxide is an appealing process because CO can be used as a commodity chemical in industrial processes. Many molecular CO2 reduction catalysts have been reported and commonly use expensive late transition metals. These systems are inspired by natural photosynthesis and generally combine a photosensitizer, a catalyst, and a sacrificial electron donor. This work focuses nickel and gold complexes as …

Utilizing Various Neural Network Architectures To Play A Game Developed For Human Players, Michael Blake Arender

Electronic Theses and Dissertations

Neural Networks have received an explosive amount of attention and interest in recent years. Despite the fact that Neural Network algorithms having existed for many decades, it was not until recent advances in computer hardware that they saw widespread use. This is in no small part due to the success these algorithms have had in tasks ranging from image classification, voice recognition, game theory, and many other applications. Thanks to recent strides in hardware development, most importantly in the advancements in Graphics Processor Units including the capabilities of modern GPU Computing, Neural Networks are now capable of solving tasks at …

Mefenamic Acid – Hpmc As Hg Amorphous Solid Dispersions: Dissolution Enhancement Using Hot Melt Extrusion Technology, Ashay Shukla

Electronic Theses and Dissertations

Mefenamic acid, a BCS class II drug, displays high permeability and low solubility, thereby exhibiting a poor dissolution profile. Hence to improve the solubility and dissolution rate of Mefenamic acid, Hot Melt Extrusion (HME) technique was employed. The amorphous solid dispersion matrix exhibited enhanced dissolution with desired release characteristics. Hydroxypropylmethylcellulose acetate succinate (AquaSolve™ HPMC-AS HG) was used as a carrier with the poloxamer (Kolliphor P407). The drug load was varied from 20% to 40% within the blend. Drug and polymers were blended using a twin shell V-blender for 10 minutes and extruded using an 11mm twin-screw co-rotating extruder (ThermoFisher Scientific, …

Characterization Of Hydrogen Bonding, Halogen Bonding And Argyrophilic Interactions Using Computational Modeling, Sarah Nicole Arradondo

Electronic Theses and Dissertations

Non-covalent interactions govern multiple important chemical processes throughout nature from those within the human body to the complex environment of the atmosphere. Quantum mechanical electronic structure modeling of these relatively weak interactions can provide molecular level insight that can further our understanding of specific macroscopic properties. In the present work different non-covalent interactions are computationally evaluated within four systems. A small prototypical hydrogen bonded system and the various structural motifs that promoted proton transfer within concentrated acid and water clusters are characterized with sophisticated wavefunction based methods and large robust basis sets in order to accurately predict the structures energies …

Improving Random Forests By Feature Dependence Analysis, Silu Zhang

Electronic Theses and Dissertations

Random forests (RFs) have been widely used for supervised learning tasks because of their high prediction accuracy good model interpretability and fast training process. However they are not able to learn from local structures as convolutional neural networks (CNNs) do when there exists high dependency among features. They also cannot utilize features that are jointly dependent on the label but marginally independent of it. In this dissertation we present two approaches to address these two problems respectively by dependence analysis. First a local feature sampling (LFS) approach is proposed to learn and use the locality information of features to group …

Mercury In Big Cypress Bayou And Caddo Lake Watersheds In Marion And Harrison Counties Texas, Joseph Watkins

Electronic Theses and Dissertations

Caddo Lake has been included on the Texas Commission on Environmental Quality 303(d) list for impairment due to mercury (Hg) content since 1996. One of the primary tributaries, Big Cypress Bayou, flows across Eocene-aged rocks and sediments associated with the Wilcox Group; the Wilcox is of interest because it contains lignite coal, which has a direct link to mercury. Previous research has focused on dry deposition from fossil fuel combustion as the primary source of mercury but has not addressed the potential watershed contribution to mercury concentrations in Caddo Lake.

Big Cypress Bayou flows through Harrison and Marion counties in …

Delineation Of Karst Potential Using Lidar And Gis Analyses, Fort Hood Military Installation, Texas, Colby Reece

Electronic Theses and Dissertations

ABSTRACT

Traditional karst surveys require extensive field investigations to completely characterize large areas. They are often time-consuming, requiring up to several years to collect and categorize data. Bias is given to areas that are most easily accessible and false negatives are common. The implementation of geographic information systems (GIS) has aided in the aggregation and standardization of karst data; however, these systems have also been used to develop terrain models that allow the user to remotely delineate sinkholes and other surficial features. The Fort Hood Military Installation is a karst landscape that has been altered significantly for use in military …

Syntheses Of A Tin (Iv) Meso-Tetra(4-Pyridyl) Porphyrin Dichloride-Tetrachlorobis (Bipy)2 Ruthenium (Ii) Complex And Studies Of Photophysical Properties Of 1-Nitropyrene, Phillip Sharp

Electronic Theses and Dissertations

Development of a photosensitizer that can work in both aerobic and anaerobic environments would increase the robustness of the cancer treatment known as photodynamic therapy. The development of a photosensitizer was first attempted by synthesizing a tin (IV) meso-tetra (4-pyridyl) porphyrin dichloride-tetrachlorobis (Bipy)₂ ruthenium (II) complex. The synthesize of the tin porphyrin was done by a method from literature and had a percent error of 31.58 and 37.31 when comparing the theoretical percentages of carbon (55.39) and nitrogen (12.92) meaning that photosensitizer was not synthesized.

The second type of chromophore that was studied was 1-nitropyrene do determine if it …

Innate Immunity, The Hepatic Extracellular Matrix, And Liver Injury: Mathematical Modeling Of Metastatic Potential And Tumor Development In Alcoholic Liver Disease., Shanice V. Hudson

Electronic Theses and Dissertations

The overarching goals of the current work are to fill key gaps in the current understanding of alcohol consumption and the risk of metastasis to the liver. Considering the evidence this research group has compiled confirming that the hepatic matrisome responds dynamically to injury, an altered extracellular matrix (ECM) profile appears to be a key feature of pre-fibrotic inflammatory injury in the liver. This group has demonstrated that the hepatic ECM responds dynamically to alcohol exposure, in particular, sensitizing the liver to LPS-induced inflammatory damage. Although the study of alcohol in its role as a contributing factor to oncogenesis and …

Investigating The Unique Reactivity Of Novel Hx (X=Cl, Br) Reagents With Alkenes And Alkynes., Rene E. Ebule

Electronic Theses and Dissertations

The addition of hydrogen halides to carbon-carbon unsaturated systems is a classic synthetic transformation that gives rise to a variety of halogenated products as well as building blocks.¹ The different routes to achieve hydrohalogenation make use of the hydrogen halides either in the gaseous form² or in solution³, or their surrogates⁴. Only second to dihalogens, hydrogen halides are the most atom efficient source of halogenation. However, hydrogen halides are reactive gases at ambient temperature, posing a major challenge in their application. Handling gaseous hydrogen halide reagents requires expert knowledge and specialized equipment. We have …

A Transfer Learning Approach For Sentiment Classification., Omar Abdelwahab

Electronic Theses and Dissertations

The idea of developing machine learning systems or Artificial Intelligence agents that would learn from different tasks and be able to accumulate that knowledge with time so that it functions successfully on a new task that it has not seen before is an idea and a research area that is still being explored. In this work, we will lay out an algorithm that allows a machine learning system or an AI agent to learn from k different domains then uses some or no data from the new task for the system to perform strongly on that new task. In order …

A Normal Form For Words In The Temperley-Lieb Algebra And The Artin Braid Group On Three Strands, Jack Hartsell

Electronic Theses and Dissertations

The motivation for this thesis is the computer-assisted calculation of the Jones poly- nomial from braid words in the Artin braid group on three strands, denoted B3. The method used for calculation of the Jones polynomial is the original method that was created when the Jones polynomial was first discovered by Vaughan Jones in 1984. This method utilizes the Temperley-Lieb algebra, and in our case the Temperley-Lieb Algebra on three strands, denoted A3, thus generalizations about A3 that assist with the process of calculation are pursued.

Italian Domination On Ladders And Related Products, Bradley Gardner

Electronic Theses and Dissertations

An Italian dominating function on a graph $G = (V,E)$ is a function such that $f : V \to \{0,1,2\}$, and for each vertex $v \in V$ for which $f(v) = 0$, we have $\sum_{u\in N(v)}f(u) \geq 2$. The weight of an Italian dominating function is $f(V) = \sum_{v\in V(G)}f(v)$. The minimum weight of all such functions on a graph $G$ is called the Italian domination number of $G$. In this thesis, we will consider Italian domination in various types of products of a graph $G$ with the complete graph $K_2$. We will find the value of the Italian domination …

Improving Sinkhole Mapping Using Lidar Data And Locating Sinkhole Hotspots In Johnson City, Tn, Kingsley Fasesin

Electronic Theses and Dissertations

Predicting infrastructure damage and economic impact of sinkholes requires high accuracy mapping distribution and development. The study mapped sinkholes and sinkhole hotpsots in Johnson City, TN using LiDAR-derived Digital Elevation Model (DEM) and a database of known sinkholes which were matched to LiDAR-derived depressions. For all matched depressions (n = 404), three metrics were calculated: circularity index, ratio of length to width of the Minimum Bounding Rectangle (MBR) and percent coverage of the MBR by the depression, and 3,634 new sinkholes were identified. Newly developed hotspots were identified in north Johnson City and other areas in the south near the …

Imidacloprid Persistence, Mobility, And Effect On Ecosystem Function, Joanna Hardin

Electronic Theses and Dissertations

Imidacloprid is a neonicotinoid pesticide used to protect against biting and sucking insects. Land managers rely on its systemic properties, however long-term studies investigating imidacloprid effects on ecosystem function are limited. This study investigated imidacloprid applications to Tsuga caroliniana and Tsuga canadensis over time and compared concentrations to measures of ecosystem function including soil respiration, microbial function, and invertebrate density. Results indicate that imidacloprid is persistent (p0.5). Microbial function and invertebrate density were not significantly different between control and treatment locations nor did imidacloprid concentrations correlate with ecosystem functional indicator activity (p>0.05). It is evident that imidacloprid does not …

Framing Climate Change As National Security: A Survey-Experiment On Climate Change Perceptions., Adam Lyons

Electronic Theses and Dissertations

The issues surrounding climate change continue to have polarizing effects on many Americans. In this thesis I offer a potential bridge to this divide with a comprehensive study on how issue frames can impact how individuals shape their opinions on environmental issues. Focusing on a national security frame, I ask the central research “Will the public perceive issues of climate change differently when they are framed as threats to national security?” For this thesis I design an original experimental survey to measure the impact security framing has on participants’ perception of both climate change and environmental policy options. The survey …

Effectiveness Of Prescribed Fire On Meeting Fuel Load And Wildlife Habitat Management Objectives In East Texas National Forests, Trey Wall

Electronic Theses and Dissertations

Using standardized methodology outlined by the United States Forest Service and the National Forests and Grasslands in Texas’ Fire Monitoring Program for data collection, the efficacy of current Forest Service prescribed burn regimes were analyzed for 24 study sites in East Texas National Forests. Study sites were located within Sam Houston, Davy Crockett, and Angelina/Sabine National Forests. Efficacy was determined by comparing defined management objectives established by the Forest Service to the data collected at the study sites. The results conclude that most objectives, as outlined by the Forest Service, are not being met with the current practices. Re-visitation of …

Physical And Chemical Controls On Suffosion Development In Gypsic Soil, Culberson County, Texas, Jonah Morris

Electronic Theses and Dissertations

In the Gypsum Plain, suffosion processes have encouraged road failure through dissolution and transport of gypsic soils; however, no prior research has been conducted within the Delaware Basin in regard to these processes. These phenomena were evaluated in both field and laboratory settings in order to assess the parameters of suffosion development associated with Ranch to Market (RM) 652 in Culberson County, Texas, where infrastructure extends across Castile and Rustler strata. Field studies simulated surficial ponding in various gypsic soils and correlated suffosion potential with soil composition and thickness. Soluble fractions of gypsic soils were delineated through geochemical analyses, further …

The Ecology Of Fecal Indicators, Dennis A. Gilfillan

Electronic Theses and Dissertations

Animal and human wastes introduce pathogens into rivers and streams, creating human health and economic burdens. While direct monitoring for pathogens is possible, it is impractical due to the sporadic distribution of pathogens, cost to identify, and health risks to laboratory workers. To overcome these issues, fecal indicator organisms are used to estimate the presence of pathogens. Although fecal indicators generally protect public health, they fall short in their utility because of difficulties in public health risk characterization, inconsistent correlations with pathogens, weak source identification, and their potential to persist in environments with no point sources of fecal pollution. This …

Computational Quantum Chemistry Studies Of The Interactions Of Amino Acids Side Chains With The Guanine Radical Cation., Edward Acheampong

Electronic Theses and Dissertations

Guanine is generally accepted as the most easily oxidized DNA base when cells are subjected to ionizing radiation, photoionization or photosensitization. At pH 7, the midpoint reduction potential is on the order of 0.2 – 0.3 V higher than those of the radicals of e.g. tyrosine, tryptophan cysteine and histidine, so that the radical “repair” (or at least, a thermodynamically favorable reaction) involving these amino acids is feasible. Computational quantum studies have been done on tyrosine, tryptophan, cysteine and histidine side chains as they appear in histones. Density functional theory was employed using B3LYP/6-31G+ (d, p) basis set to study …