Physical Sciences and Mathematics Commons^™

Novel Approaches To The Determination Of Toxic Metals In Industrial Waste And Soil Extracts, Garrett Bruce Finn

Theses and Dissertations

Abstract:Because of their environmental impact, the contamination and migration of heavy metals is an important field of study. In this thesis, two novel methods for measuring toxic metals over a broad concentration range in complex matrices were successfully developed and applied to authentic samples. This research focused on toxic metals in two disparate environments: industrial effluent and soil. The primary work reported in this research focused on developing a Sequential Injection Analysis (SIA) process monitor to measure metals in industrial process waste streams in near real-time. Molecular Absorption Spectroscopy was used to determine levels of Zn and several other metals. …

Effects Of Intercalation And Deintercalation In Layered Materials: From Topological Insulators To Battery Cathodes, Uma Garg

Theses and Dissertations

Topological insulators are quantum materials which have insulating bulk and conducting surface. The surface states in these materials is protected by time reversal symmetry and spin-orbit coupling. The fascinating quantum properties of these materials could lead to high speed electronics and quantum computing. To explore the transport properties of these systems, I synthesized single crystals of SnTe and Sb2Se3 which are potential topological insulators. SnTe is a topological crystalline insulator in which topological surface states are protected by time reversal symmetry and crystal symmetry, in particular mirror symmetry. My Shubnikov-de Haas (SdH) oscillation study on the (001) surface of SnTe …

Characterization Of Fiber Bragg Grating Based, Geometry-Dependent, Magnetostrictive Composite Sensors, Edward Lynch

Theses and Dissertations

Optical sensors based on geometry dependent magnetostrictive composite, having potential applications in current sensing and magnetic field sensing are modeled and evaluated experimentally with an emphasis on their thermal immunity from thermal disturbances. Two sensor geometries composed of a fiber Bragg grating (FBG) embedded in a shaped Terfenol-D/epoxy composite material, which were previously prototyped and tested for magnetic field response, were investigated. When sensing magnetic fields or currents, the primary function of the magnetostrictive composite geometry is to modulate the magnetic flux such that a magnetostrictive strain gradient is induced on the embedded FBG. Simulations and thermal experiments reveal the …

Trace: A Differentiable Approach To Line-Level Stroke Recovery For Offline Handwritten Text, Taylor Neil Archibald

Theses and Dissertations

Stroke order and velocity are helpful features in the fields of signature verification, handwriting recognition, and handwriting synthesis. Recovering these features from offline handwritten text is a challenging and well-studied problem. We propose a new model called TRACE (Trajectory Recovery by an Adaptively-trained Convolutional Encoder). TRACE is a differentiable approach using a convolutional recurrent neural network (CRNN) to infer temporal stroke information from long lines of offline handwritten text with many characters. TRACE is perhaps the first system to be trained end-to-end on entire lines of text of arbitrary width and does not require the use of dynamic exemplars. Moreover, …

Classification Of Jacobian Elliptic Fibrations On A Special Family Of K3 Surfaces Of Picard Rank Sixteen, Thomas Hill

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

K3 surfaces are an important tool used to understand the symmetries in physics that link different string theories, called string dualities. For example, heterotic string theory compactified on an elliptic curve describes a theory physically equivalent to (dual to) F-theory compactified on a K3 surface. In fact, M-theory, the type IIA string, the type IIB string, the Spin(32)/Z₂ heterotic string, and the E₈ x E₈ heterotic string are all related by compactification on Calabi-Yau manifolds.

We study a special family of K3 surfaces, namely a family of rank sixteen K3 surfaces polarized by the lattice H⊕E …

Environmental Controls On Didymosphenia Geminata Bloom Formation, Lindsay Capito

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Climate change is causing rapid glacial recession and earlier snowmelt, which alter the physical and chemical properties of rivers. As a result, organisms at the base of the food web are responding in unforeseen ways. We use the nuisance algae D. geminata (Didymo) as a case study for how climate induced shifts in the timing of glacial and snowmelt runoff are affecting river ecosystems. We evaluated how shifts in the timing of nutrient concentrations and light availability affect nuisance blooms of Didymo in three complementary ways. These are, field studies across streams in various stages of glacial recession, weekly measurements …

Deep Q Learning Applied To Stock Trading, Agnibh Dasgupta

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Developing a strategy for stock trading is a vital task for investors. However, it is challenging to obtain an optimal strategy, given the complex and dynamic nature of the stock market. This thesis aims to explore the applications of Reinforcement Learning with the goal of maximizing returns from market investment, keeping in mind the human aspect of trading by utilizing stock prices represented as candlestick graphs. Furthermore, the algorithm studies public interest patterns in form of graphs extracted from Google Trends to make predictions. Deep Q learning has been used to train an agent based on fused images of stock …

Development Of Hplc Stationary Phases With Unique Selectivities And Introduction Of Molecular Rotational Resonance Spectroscopy In Gas Chromatography, Nimisha Thakur

Chemistry & Biochemistry Dissertations

This thesis contributes to advancing liquid and gas chromatography by introducing new stationary phases for HPLC and a new hyphenated GC technique. In the first section, new pH stable stationary phases based on geopolymers are presented for applications in liquid chromatography. The first-ever synthesis of micron-sized spherical particles of geopolymers, customized to be used as HPLC stationary phases, is reported. Complete material characterization of geopolymers using X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, laser diffraction, and porosimetry is shown. The chromatographic evaluation of geopolymers is done by comparing parameters such as hydrophilicity, ion exchange selectivity, efficiency, hydrolytic stability, and …

Investigation Of Clinoptilolite Zeolite As A Candidate System For Study By Positron Annihilation, Edward Perez

Physics Theses

This thesis reports on the characterization of a clinoptilolite zeolite (〖Na〗_3 [〖Al〗_3 〖Si〗_15 O_36 ]12H_2 O) using Energy-dispersive X-ray spectroscopy (EDX/EDS) for chemical analysis, low energy Secondary Electron (SE) analysis for three-dimensional imaging and topography, and Transmission Electron Microscopy (TEM) for two-dimensional imaging at the nanometer level. The goal of this work was to provide additional information that can aid in the interpretation of the data obtained using positron beam based spectroscopies. The measurements were performed using the Hitachi S-3000N Variable Pressure Scanning Electron Microscope (SEM) integrated with a NORAN 7 EDS/EBSD system, the Hitachi S-4800 II Field Emission Scanning …

Stable Isotope Composition Of Surface Water Across Central Mexico, Jordan Foote

Earth & Environmental Sciences Theses

Understanding the controlling factors of modern surface water stable isotope compositions is important for reconstructions of paleoclimate and paleoelevation. Few studies have attempted to understand patterns of surface water isotope compositions and their controlling factors in Mexico. Here I study the δ18O, δD and d-excess values of 124 modern river, lake and spring water samples across the Sierra Madre Occidental, Central Mexican Plateau and Sierra Madre Oriental to constrain the spatial pattern and lapse rate. These samples were collected at various elevations after the wet season in 2019. The isotope data were integrated with moisture back trajectory analysis and climatic …

Report On Icdp Deep Dust Workshops: Probing Continental Climate Of The Late Paleozoic Icehouse-Greenhouse Transition And Beyond, Gerilyn S. Soreghan, Laurent Beccaletto, Kathleen C. Benison, Sylvie Borquin, Georg Feulner, Natsuko Hamamura, Michael Hamilton, Nicholas G. Heavens, Linda Hinnov, Adam Huttenlocker, Cindy Looy, Lily Pfeifer, Stephane Pochat, Mehrdad Sarder Abadi, James Zambito

School of Earth & Environment Departmental Research

Chamberlin and Salisbury's assessment of the Permian a century ago captured the essence of the period: it is an interval of extremes yet one sufficiently recent to have affected a biosphere with near-modern complexity. The events of the Permian – the orogenic episodes, massive biospheric turnovers, both icehouse and greenhouse antitheses, and Mars-analog lithofacies – boggle the imagination and present us with great opportunities to explore Earth system behavior. The ICDP-funded workshops dubbed “Deep Dust,” held in Oklahoma (USA) in March 2019 (67 participants from nine countries) and Paris (France) in January 2020 (33 participants from eight countries), focused on …

Total Synthesis Of Cytotoxic Mansouramycins From Amino Acids, Beatriz Gamez

Theses and Dissertations

Natural products produced by plants, animals, and microorganisms are of significant importance in chemistry for being major sources of molecular scaffolds essential for new drug discovery. Mansouramycins are cytotoxic bioactive compounds containing isoquinoline skeletons with substituents on the quinone and pyridine rings that may be difficult to synthesize. Synthetic processes exist for compounds B and D, however, there exists an absence of simple synthetic approaches to all four alkaloids.

This project aims to provide a general total synthetic pathway to Mansouramycins A—D from amino acids for possible use in cancer treatment via these isoquinolinequinones. Preliminary experimentation suggests there may be …

The Dmap-Catalyzed Acylation Of Alcohol -- A Mechanistic Study, Tania Veronica Alvarez Castro

Theses and Dissertations

The mechanistic studies of Acylation of Alcohols catalyzed by 4-(N,N- Dimethyl-amino)-pyridine (DMAP) has been heavily studied in the literature. This reaction has attracted considerable interest from the synthetic and mechanistic points of view in recent years. In this research, the acylation of alcohols is prepared from cyclohexanol and acetic anhydride that is catalyzed by DMAP using triethyl amine (NEt3) as the auxiliary base and dichloromethane (DCM) as solvent. The reaction and final product will be analyzed by using gas chromatography (GC) and reaction progress kinetic analysis (RPKA). The mechanistic insights obtained in the present study should be useful for understanding …

Synthesis, Characterization, And Application Of Meso-Tetraphenyl Metalloporphyrin Photocatalysts Under Visible Light, Alexis Echavarria

Theses and Dissertations

The photocatalytic activity of meso-Tetraphenyl Metalloporphyrins with different metal centers was investigated. The synthesized metalloporphyrin photocatalysts was performed and analyzed using FT-IR spectroscopy, UV-VIS spectroscopy, and powder X-Ray Diffraction analysis. The synthesized TPP crystals were determined to be tetragonal crystal structure and the structure was observed in all synthesized metalloporphyrin catalysts. The Soret (B) bands, Q bands, FT-IR functional groups were identified. Reaction progress was investigated by sampling at intervals of one hour and analysis of the samples was performed using Gas Chromatography-Mass Spectrometry. GC-MS analysis was used to identify the products of the photochemical catalytic redox reactions performed under …

Reinforcement Learning Environment For Orbital Station-Keeping, Armando Herrera Iii

Theses and Dissertations

In this thesis, a Reinforcement Learning Environment for orbital station-keeping is created and tested against one of the most used Reinforcement Learning algorithm called Proximal Policy Optimization (PPO). This thesis also explores the foundations of Reinforcement Learning, from the taxonomy to a description of PPO, and shows a thorough explanation of the physics required to make the RL environment. Optuna optimizes PPO's hyper-parameters for the created environment via distributed computing. This thesis then shows and analysis the results from training a PPO agent six times.

On Coupled Reaction Diffusion Equations And Their Applications, Juan J. Huerta

Theses and Dissertations

Reaction-diffusion equations are nonlinear partial differential equations that have been used extensively in mathematical modeling. An interesting case in this type of equation is the Fisher-Kolmogorov system, which has been used to study a low-grade glioma, a group of primary brain tumors. In the first part of this thesis, a stochastic version of the Fisher-Kolmogorov system will be studied, and exact and numerical solutions will be presented.

The second part of this thesis will show how the speed of information propagation affects disease spread and vaccination uptake through networks in epidemics. In this model, the information reaches different people at …

Chemical Modification And In Silico Validation Of Medicinally Privileged Molecular Scaffolds As Kras And Sars-Cov-2 Protease Inhibitors, Precious M. Okwuchukwu

Theses and Dissertations

Coronavirus disease was declared a global pandemic by WHO in March 2020, cancer is the second leading cause of death by a disease. Several scientists around the world are working relentlessly to discover an effective remedy to eradicate these deadly diseases. A natural polyphenol (magnolol) has been isolated from a tree Magnolia grandiflora (family Magnoliaceae) found on UTRGV campuses. This research is focused on design of a series of chemically modified sulfonyl derivatives based on the isolated magnolol framework and other medicinally privileged molecular scaffolds framework that can effectively bind to the COVID-19 main protease, SARS- CoV-2 3CL protease …

Thermal And Spectroscopic Investigations On Polymer-Based Nanofibers, Omosola Oriretan

Theses and Dissertations

Nanofibers of Poly (ethylene oxide), PEO, Poly (vinylpyrrolidone) PVP, Co-nanofiber of PEO-PVP and PEO nanocomposite of various Fullerene compositions were prepared by dissolving PEO, PVP and Fullerene in water. The Fullerene nanoparticles were added to the PEO solutions, the mixtures were homogenized under high power sonication. The PEO solutions, PVP solutions, the co-polymer solutions of PEO-PVP and the PEO -Fullerene solutions were centrifugally spun using Force spinning™ machine. The obtained nanofibers and the nanocomposites were subjected to FTIR analysis, Raman analysis and various heating and cooling cycles with heating and cooling rates ranging from 10C/min to 600C/min using differential scanning …

Effects Of Elevated Temperature On 8-Hydroxy-2'-Deoxyguanosine Expression, Dna Damage And Cellular Apoptosis In The American Oyster (Crassostrea Virginica), Md Faizur Rahman

Theses and Dissertations

Global temperature increases due to anthropogenic activities. The effects of rising temperature are well documented in aquatic organisms. The American oyster is an ideal shellfish species to study on global warming and oxidative DNA damage. In this study, We observed the effects of high temperature on heat shock protein-70 (HSP70), 8-hydroxy-2’-deoxyguanosine (8-OHdG), ssDNA, dsDNA, caspase-3 (CASP3), BAX and γH2AX, a molecular marker of DNA damage, protein expressions in gills of oysters. Immunohistochemical results showed that elevated temperatures (28 and 32°C) significantly increased HSP70, 8-OHdG, dsDNA, γH2AX, BAX and CASP3 protein expressions in gills of oysters compare to control (24°C). In …

A Targeted Adversarial Attack On Support Vector Machine Using The Boundary Line, Yessenia Rodriguez

Theses and Dissertations

In this thesis, a targeted adversarial attack is explored on a Support Vector Machine (SVM). SVM is defined by creating a separating boundary between two classes. Using a target class, any input can be modified to cross the “boundary line,” making the model predict the target class. To limit the modification, a percentage of an image of the target class is used to get several random sections. Using these sections, the input will be moved in small steps closer to the boundary point. The section that took the least number of steps to cause the model to predict the target …

Water, Fish, And Fire: Interdisciplinary Research On Ecosystem Services And Climate Adaptation, Liana Prudencio

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ecosystem services, or benefits from the environment, are plentiful and vary from place to place. Human activities and climate change have impacted these services in every region of the world. This dissertation explores multiple ecosystem services, from water quality improvement to provisioning of fish and habitat, in multiple and international contexts. The first chapter synthesizes the literature on stormwater management and ecosystem services, finding that research at this intersection has provided many parcel-level studies and frameworks for implementing green infrastructure. The second chapter extends the stormwater management literature by quantifying the impacts of green infrastructure on water quantity and quality …

Delta Hedging Of Financial Options Using Reinforcement Learning And An Impossibility Hypothesis, Ronak Tali

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In this thesis we take a fresh perspective on delta hedging of financial options as undertaken by market makers. The current industry standard of delta hedging relies on the famous Black Scholes formulation that prescribes continuous time hedging in a way that allows the market maker to remain risk neutral at all times. But the Black Scholes formulation is a deterministic model that comes with several strict assumptions such as zero transaction costs, log normal distribution of the underlying stock prices, etc. In this paper we employ Reinforcement Learning to redesign the delta hedging problem in way that allows us …

The Development And Use Of A Secondary Electron Yield Database For Spacecraft Charge Modeling, Phillip Lundgreen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Charge modeling of electron-solid interactions requires a detailed and accurate compilation of experimental data on which to base its physics and against which to test its predictions. Historically researchers used methods involving individual research or information taken from existing, vague, databases that were often found wanting. To streamline the charge modeling process, a collection of data has been assembled and categorized based upon surface morphology and contamination from various published sources and existing databases. The quality and quantity of the compilation vary widely with very little information offered with regards to surface conditions of various materials (contamination, morphology, etc. ...). …

Exact Generalized Voronoi Diagram Computation Using A Sweepline Algorithm, Daniel Marsden

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Voronoi Diagrams can provide useful spatial information. Little work has been done on computing exact Voronoi Diagrams when the sites are more complex than a point. We introduce a technique that measures the exact Generalized Voronoi Diagram from points, line segments and, connected lines including lines that connect to form simple polygons. Our technique is an extension of Fortune’s method. Our approach treats connected lines (or polygons) as a single site.

A Thermochronometric, Microtextural, And Numerical Modeling Approach To Deciphering The Rock Record Of Deformation Processes In The Wasatch And Denali Fault Zones, Robert G. Mcdermott

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fault zones are the primary features that accommodate movement of Earth’s crust, resulting in the formation of mountain belts and damaging earthquakes. Rocks modified by faulting and brought to Earth’s surface by erosion are archives of the mechanical processes involved in earthquakes and(or) aseismic creep. Thermochronometry is a radioisotopic dating system primarily sensitive to temperature and offers a means to constrain dates and rates of thermal processes. Hematite is common in fault zones, amenable to (U-Th)/He (He) thermochronometry, and exhibits distinct microtextures diagnostic of fault zone mechanics. I apply hematite He thermochronometry and microtextural analyses with a suite of other …

Pre-Eruptive Evolution Of Izu-Bonin Boninite Melts: Mixing, Cooling, And Crystallization, Jesse L. Scholpp

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Subduction is the geologic process in which one tectonic plate moves beneath another as it sinks into the Earth’s mantle. Subduction initiation in the Izu-Bonin Marianas system is the result of a gravitational failure during which one tectonic plate (the Pacific plate) spontaneously sinks beneath another (the Philippne Sea plate). Fluids released by the sinking plate that caused the overlying mantle to melt by reducing its meltimg temperature, forming the Izu-Bonin Mariana island arc system.

The resulting melts initially have the chemical compositions that are rich in silica and magnesia, and highly depleted in other elements, refered to a boninite …

Micro Grid Control Optimization With Load And Solar Prediction, Shaju Saha

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Using renewable energy can save money and keep the environment cleaner. Installing a solar PV system is a one-time cost but it can generate energy for a lifetime. Solar PV does not generate carbon emissions while producing power. This thesis evaluates the value of being able to make accurate predictions in the use of solar energy. It uses predicted solar power and load for a system and a battery to store the energy for future use and calculates the operating cost or profit in several designed conditions. Various factors like a different place, tuning the capacity of sources, changing buy/sell …

Job Satisfaction And Employee Turnover Determinants In Fortune 50 Companies: Insights From Employee Reviews From Indeed.Com, Bishal Sainju

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

We explored 682176 employee reviews of Fortune 50 companies from Indeed.com using topic discovery techniques like Latent Dirichlet Allocation (LDA) and Structural Topic Modeling (STM) to identify salient aspects in employee reviews and automatically infer latent topics that tend to drive employee satisfaction. We also studied how various satisfaction factors could be related to employee turnover. We discovered important topics in the reviews, including Management and Leadership, Advancement Opportunity, Pay and Benefits, Work-Life Balance, and Culture, which we compare to the five Job Descriptive Index (JDI) facets. Both LDA and STM discovered well-separated and distinguishable topics. We also …

Automation Of Feature Selection And Generation Of Optimal Feature Subsets For Beehive Audio Sample Classification, Aditya Bhouraskar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The last couple of decades have witnessed an abnormal phenomenon of reduction in the bee population, this is a serious matter of concern as three out of four crops available globally have honey bee as their sole pollinator causing significant economic losses and an unbalance in the ecosystem. There have been many theories about the cause of bee colony collapses such as parasites, pesticides and poor nutrition however conclusive evidence of this phenomenon is yet to be identified.

Human inspection of beehives requires precision. It takes an experienced beekeeper to determine the health of a hive by the sounds generated …

Effects Of The Radiation Belt On The Plasmasphere Distribution, Stefan Thonnard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study examines the interaction of plasma, ions and electrons created by Solar illumination in the Earth’s upper atmosphere, that travels along magnetic field lines filling the Plasmasphere, and the naturally occurring trapped particles known as the outer radiation belt. Although these two science disciplines have been largely worked independent of each other due the vast differences in the energy of the particles, recent satellite observations indicate a large population of particles with lower energy and greater mass also exist in the outer radiation belt. This study shows that during conditions of low solar output in an 11-year cycle, these …