Physical Sciences and Mathematics Commons^™

Snook (Centropomus Undecimalis) Behavior And Accelerometer Telemetry In The Bahia Grande Of Texas, Jonathan Truett Cawlfield

Theses and Dissertations

There has been very little study of the Texas population of snook. No studies have have looked at behavior in the Texas snook population. In this study we look at behavioral patterns and activity level in Lower Laguna Madre snook utilizing accelerometer telemetry tags. Twenty-one common snook were surgically implanted with tags and monitored from summer and fall of 2019 until September 2020. The accelerometer tags which sum acceleration over the x, y, and z planes calculated (ODBA) which was used to estimate behavior. This behavior was then compared with environmental data like diel period, tidal period, water temperature, and …

Flexible Quantum Dot Solar Cell With Nanostructure Titanium Dioxide Photoanode With Modified Counter Electrode, Haimanti Majumder

Theses and Dissertations

Because of unique photovoltaic properties, nanostructured morphologies of TiO2 on flexible substrate have been studied widely in recent years in dye-sensitized solar cells (DSSCs). Nanostructured electrode materials with high surface area can promote rapid charge transport and thus improve the light-to-current conversion efficiency. Herein, this project generates an improved photoanode with forest like photoactive TiO2 hierarchical microstructure using a simple and facile hydrothermal route. To improve the photocurrent efficiency, PbS quantum dot has been applied in different thicknesses to evaluate the best performance. The deposition of quantum dot was done by easy SILAR cycle. Four different SILAR cycle has been …

Microwave Spectroscopy Of Cyclohexanecarboxylic Acid, Chlorosulfonic Acid, And Its Interaction With Water, Diego Erik Rodriguez

Theses and Dissertations

This study combines computational chemistry and microwave spectroscopy to simulate the behavior of two molecules: cyclohexanecarboxylic acid and chlorosulfonic acid. In this thesis, cyclohexanecarboxylic acid will be observed on its own. On the other hand, chlorosulfonic acid will be observed on its own as well as its interaction with one, two, and three water molecules. Chapter 1: Introduction will provide insight on published literature related to cyclohexanecarboxylic acid, chlorosulfonic acid, and perfluoroalkyl substances. Chapter 2: Computational Chemistry will provide the reader with information about the foundation of computational chemistry including theory and development of the science. Chapter 3: Microwave Spectroscopy …

Managing Water Resource And Land Use In Lower Rio Grande Valley Of South Texas Using A Groundwater Vulnerability Model, Leslie Soto Sanchez

Theses and Dissertations

The Lower Rio Grande Valley (LRGV) has three Metropolitan Statistical Areas. These are Brownsville-Harlingen, Laredo, and McAllen-Edinburg-Mission, the latter with a population of around 1 million people and had an estimated growth of 62% from the period of 2010-2018 (Texas State Data Center, 2020). Low precipitations, intensive agricultures as well as growth in the manufacturing and tourism industries have resulted in an increasing concern of scarce water supply especially the region relies primarily on a single water source, the Rio Grande River. These circumstances could potentially disrupt economic development, negatively affecting the local manufacturing industry, agriculture, and the community. With …

A Statistical Comparison Of Covid-19 In The United States Across Political Affiliations And Census Regions, Margarito Torres

Theses and Dissertations

In mid-January 2020, the United States reported their first cases of the coronavirus disease (COVID-19) from a passenger returning from Wuhan, China. Initially, the situation wasn’t very alarming as in China and European countries, but the situation began to worsen in March 2020 when the number of cases began to multiply. Then, in a matter of a few months, the United States became the number one country in terms of total cases and total deaths from COVID-19. We have been closely observing the United States and the world since July 2020. Our study aims to compare the political affiliations and …

Total Synthesis Of E Stereoisomers Of Bilirubin Oxidation Products, Tess C. Ruiz

Theses and Dissertations

The purpose of the research was to synthesize the E stereoisomer of Bilirubin Oxidation Products that had not been synthesized through a total organic synthesis at the start of this project. There were numerous different procedures for the bromination of citraconic anhydride performed in an attempt to optimize yield and purity. A proposed scheme for the total synthesis of the E isomers was constantly updated and altered while the project was ongoing. The bioactivity of the compounds was to be tested if the project had been finished. This might have contributed to a greater understanding of their function and association …

Electrospun Pcl And Pcl/Gel Microfiber Scaffolds As Prototypes For Anterior Cruciate Ligament (Acl) Regeneration And Repair, Diego Rivera

Theses and Dissertations

Polycaprolactone (PCL) is a polymer that has been a focus of tissue engineering due to its range of applicability for biomedical applications. Synthesis of PCL from a microwave-assisted and stannous octoate-catalyzed ring-opening reaction with ε-caprolactone was accomplished. Aligned-fiber microfiber mats were generated via electrospinning for characterization. PCL microfiber mats were characterized via FTIR and scanning electron microscopy. These PCL microfiber mats were mechanically tested to examine their applicability as tools for knee ligament repair. During tensile testing, non-fiber aligned mats lacked the sufficient elastic modulus. Fiber-aligned PCL samples both and gelatin-coated were tested and showed enhanced elastic modulus and extension …

Conceptual Insight Into The Application Of Innovative Educational Methods In Astronomy, Wahltyn A. Rattray

Theses and Dissertations

University students taking introductory astronomy courses were studied with a control group enrolled in a class with standard curriculum and an experimental group enrolled in a class with a curriculum using innovative instructional methods. Using multiple assessments, I analyzed the students’ astronomy knowledge and overall class experience to determine which curriculum was more instructionally effective. The innovative methods were developed with the ADDIE method and were based on the Karplus learning cycle which provided the framework for the astronomy curriculum. The end goal of the innovative curriculum is to produce graduates with better conceptual understanding of astronomy than with the …

Growth Kinetics Of Salmonella Spp. During Post-Harvest Storage Of Fresh And Fresh-Cut Papaya, Amandeep Singh

Theses and Dissertations

Fresh produce safety is major concern in United States. Fresh produce has been associated with numerous food-borne outbreaks each year. Salmonella has been a recurring issue in the papaya industry. Since 2010, imported papayas have been implicated in 8 multistate outbreaks associated with Salmonella spp. causing 480 illnesses, 113 hospitalization and 3 deaths. The main reason behind this problem is as fresh papaya is grown on fields where they are constantly exposed to preharvest microbial contamination through contaminated irrigation water, agricultural soil, raw manure and/or feces deposited by intruding domestic or wild animals. Moreover, majority fresh papaya is also consumed …

Dynamical Casimir Effect In A Superconducting Circuit Periodic Lattice, Andres Cuellar Vega

Theses and Dissertations

The dynamical Casimir effect (DCE) is the generation of real photons out of the quantum vacuum due to a rapid modulation of boundary conditions for the electromagnetic field, such as a mirror oscillating at speeds comparable to the speed of light. Previous work demonstrated experimentally that DCE radiation can be generated in electrical circuits based on superconducting microfabricated waveguides, where a rapid modulation of boundary conditions corresponding to semi-transparent mirrors is realized by tuning the applied magnetic flux through superconducting quantum-interference devices (SQUIDs) that are embedded in the waveguide circuits. We propose a novel SQUID periodic lattice architecture, in which …

Microwave Assisted Depolymerization Of Waste Pet Bottles Via Glycolysis, Kingsley Bassey

Theses and Dissertations

One of the most promising and sustainable chemical depolymerization methods for managing the complex environmental problem arising from waste poly(ethylene) terephthalate (PET) bottles is glycolysis. However key challenges such as longer reaction times, complex separation procedures for the depolymerized products, selectivity, thermally stable catalyst need to be addressed.

In this work, we investigated the glycolysis of waste PET under microwave conditions using 1,5,7-Triazabicyclo [4.4.0] dec5-ene (TBD) and 1,8-Diazabicyclo [5.4.0] undec-7-ene (DBU) as catalyst. We evaluated the effect of reaction parameters such as temperature, catalyst concentration and time on PET depolymerization rate (%PET conversion) and product yield. The reaction was conducted …

Comparison Of Statistical Methods For Modeling Count Data With An Application To Length Of Hospital Stay, Gustavo A. Fernandez

Theses and Dissertations

Hospital length of stay (LOS) is a key indicator of hospital care management efficiency, cost of care, and hospital planning. Therefore, understanding hospital LOS variability is always an important healthcare focus. Hospital LOS data are count data, with discrete and nonnegative values, typically right-skewed, and often exhibiting excessive zeros. Numerous studies have been conducted to model hospital LOS to identify significant predictors contributing to its variability. Many researchers have used linear regression with or without logarithmic transformation of the outcome variable LOS, or logistic regression on a dichotomized LOS. These regression methods usually violate models’ assumptions and are subject …

Electrospun Polyetherimide And Polybenzimidazole Fibers And Composites, Fatema Ha-Mim Binta Hafiz

Theses and Dissertations

In this study, polymer micro- and nanocomposite fibers with PBI and PEI as polymer, and exfoliated graphite and nitroxide-functionalized graphene oxides have been prepared. Electrospinning has been chosen as a fiber processing technique. This work describes the electrospinning process of the mentioned polymer fibers and composite fibers followed by their characterization by XRD, ATR, SEM, TGA, DSC and Tensile testing.

Assessment And Monitoring Of Deltaic Wetlands And Fluvial Systems: Refining And Validating A Multimetric Index Of Resaca Ecosystem Health, David Lecusay Jr.

Theses and Dissertations

Resacas are ancient distributary channels of the lower Rio Grande River historically serving as floodwater drainage pathways onto the Laguna Madre, Texas. Resacas provide numerous ecosystem services and critical habitat for many species. Mainly influenced by urbanization, integrating a multimetric index for assessing and monitoring resaca ecosystem health is required for adaptive management. The Resaca Health Index (RHI) integrates structural and functional components: (1) nonredundant metrics describing fish communities (Fish Community Index); (2) Trophic State Index derived from Secchi depth; (3) decay constant from riparian vegetation leaf litter decomposing in the water column; and (4) a riparian quality index based …

Factors Influencing Intent To Take A Covid-19 Test In The United States, Sheila Rutto

Theses and Dissertations

In 2020, COVID-19 became the first pandemic in the world’s history that brought the entire world to an abrupt and unexpected halt. Since the first reported case of the disease to date, the novel coronavirus has been able to wreak havoc in literary every corner of the globe and left an ever-growing number of unprecedented fatalities. The normal way of life has been disrupted, and the level of uncertainty about the end of this pandemic continues to manifest to many. Due to the urgency to bring this pandemic under control, medical officers have been able to recommend actions that people …

Effects Of Collaborative Group Activities On Students’ Interest, Course Participation, And Performance In An Online Physics Course, Airik R. Sanchez

Theses and Dissertations

The purpose of this study was to investigate the impact of the use of collaborative work activities in online physics courses as perceived by students. Nearly identical surveys were administered at the beginning and end of two semesters to ascertain student perception on the impact of the utilization on their level of interest, participation, performance as well as teamwork skills. The results show that the majority of the population tested strongly agree that collaborative work had significant effect on all core areas tested, and they support the notion that it should be further utilized in both lecture and lab portions …

The Impacts And In-Depth Study Of The Environmental Contaminant, Perfluorooctane Sulfonic Acid, And Its Interactions With Water, Karla Veronica Salazar

Theses and Dissertations

Perfluorooctanesulfonic acid (PFOS), similar to perfluorooctanoic acid (PFOA), is a synthetic chemical that has been classified as a persistent organic pollutant (POP) by the Stockholm Convention since 2009. Due to the wide previous usage, high stability, high bio-accumulative, and low degradative properties is the reason that PFOS has been found in several compartments of the environment including ocean water, ground water, air, and sediments. Due to the strong interactions generated by the sulfonic acid end, this compound has a tendency to stay in the environment for long periods of time and has proved to be difficult in the removal from …

Contributions To The Heat Capacity Of Neutron Stars, Pedro Paulo Barboza Sanson

Theses and Dissertations

In this thesis, we review the contribution to the heat capacity of different matter phases that can appear inside a Neutron Star's core, paying special attention to the magnetic dual chiral density wave (MDCDW) phase, which is characterized by an inhomogeneous chiral condensate in the presence of a magnetic field and that is expected to be favored at intermediate densities and low temperatures. Furthermore, we compare our results with the observational lower limit of the core heat capacity established from observations of transiently accreting neutron stars which give us crucial information whether certain phases are feasible to appear in the …

An Innovative Triboelectric Stent Sensor: Prospective Cardiovascular Health Monitor Device, Ulises Vidaurri Romero

Theses and Dissertations

Previous research that has focused on TENGs have lacked the proper application of this energy generator. Currently, heart disease remains the leading cause of death in the United States. With increasing demand for self-sustainable medical devices, this nitinol health monitor sensor device (NHMS) integrates the TENG applications with medical applications. The NHMS features memory shape nitinol electrodes that preserves the device structure while using PDMS and PVDF triboelectric effect to measure heart rate, blood pressure, and breathing patterns. Three constant pressures were measured in this study. At a constant pressure of stage 1, the NHMS produces an average AC of …

Nd Doped Zinc Oxide Based Flexible Pvdf Polymer Composite For Energy Harvesting And Sensory Application, Muhtasim Ul Karim Sadaf

Theses and Dissertations

Flexible Piezoelectric devices have garnered a lot of attention for their potential as energy harvesters and transducers. Zinc Oxide particularly has been doped with different metals and has been incorporated in functional polymers in order to produce flexible piezoelectric devices. In this work, a Neodymium doped Zinc Oxide based flexible piezoelectric energy harvester and sensory device has been developed. For that, neodymium doped zinc oxide has been synthesized using wet chemical co-precipitation method and then has been incorporated in Polyvinylidene Difluoride (PVDF) polymer matrix along with Multiwalled Carbon Nanotubes (MWCNT) to produce flexible piezoelectric films. Silver paste was applied on …

Significant Gene Array Analysis And Cluster-Based Machine Learning For Disease Class Prediction, Myrine A. Barreiro-Arevalo

Theses and Dissertations

Gene expression analysis has been of major interest to biostatisticians for many decades. Such studies are necessary for the understanding of disease risk assessment and prediction, so that medical professionals and scientists alike may learn how to better create treatment plans to lessen symptoms and perhaps even find cures. In this study, we will investigate various gene expression analyses and machine learning techniques for disease class prediction, as well as assess predictive validity of these models and uncover differentially expressed (DE) genes for their relevant pathology datasets. Multiple gene expression datasets will be used to test model accuracies and will …

Empirical Bayes Estimates For The Reproduction Number Of Epidemics, Elijah Lee Hight

Theses and Dissertations

Epidemic outbreaks can be modelled as a branching process in which the total progeny or outbreak size, follows a Borel-Tanner (BT) distribution. Following a procedure described by Liang (2009), we construct empirical Bayes estimates for when the initial number of infected is a specified value r. Following the construction, we then simulate data and perform a numerical study, assuming BT distribution for the parameter θ, the reproduction number, with an initial outbreak size of three. Simulation results indicate that the empirical estimator suffers from “jumpiness.” We then proceed to monotonize the empirical estimate via a method outlined by Houwelingen (1979). …

Investigation Of Techniques And Their Application For The Cryopreservation Of Algal Species, Jazmine Leija

Theses and Dissertations

An alternative source for petroleum-based crude oils are algae derived biofuels. Fossil fuels are harmful for the environment, expensive and becoming scarce. There has been an increase in research on environmentally sustainable energy, using lipids derived from microalgae, which can be converted into biofuel. The use of microalgae as a source for biofuels has a lot of benefits including decreasing greenhouse gas emissions, rapid fuel production, absorption of carbon dioxide, and production of a renewable source of energy.

Algae cryopreservation aids in the maintenance of the best algae strains selected for producing lipids for biofuels. Cryopreservation will help minimize genetic …

Particle Trajectories In Shallow Water Models, Diana Torres

Theses and Dissertations

In this paper we will study particle trajectories under shallow water waves. We will examine equations such as the Korteweg-de Vries and systems dealing with Boussinesq and Euler's Equations to find relationships between particles irrotational velocities. Their solutions and behavior when modeling interacting surface waves will be explored. An attempt to find approximate solutions with different parameters, such as small amplitude and long-crested waves, that will lead to new information and study will be discussed.

Applications Of Vanadium Phthalocyanine In Catalytic, Acid-Based Medium To Couple Sugar Molecules, Juan Ricardo Luna

Theses and Dissertations

The vanadium-substituted tetraazatetrabenzoporphyrin, vanadium phthalocyanine, was synthesized via reflux and characterized using FITR and XRD analysis. Subsequent to synthesis, the vanadium phthalocyanine was studied as a catalyst in redox reactions to convert fructose to different molecules, the products were predominately levulinic methyl ester and heptadionic acid. The ability to convert fructose to other compounds, such as alkyl levulinic derivative, is an important process to help eliminate reliance on traditional chemical feed stocks and promote alternative fuels. Levulinic acid has been commonly used as a starting material in the synthesis of biofuels and a precursor for pharmaceuticals, plasticizers, THF derivatives, γ-valerolatone. …

Chemical Investigation Of Camu Camu (Myrciaria Dubia) Leaves And Roots, Jorge L. Flores

Theses and Dissertations

Flores, Jorge L., Chemical Investigation of Camu Camu (Myrciaria dubia) Leaves and Roots. Master of Science (MS), December, 2020, 45 pp., 8 Tables, 28 Figures, 21 references, 12 titles.Being the largest on the planet, the Amazon rainforest also has the greatest biodiversity of plant life on earth. In the lowland regions of the Amazon grows the Peruvian camu camu (Myrciaria dubia) plant. A short and shaggy shrub, camu camu produces a tasty but sour fruit. Camu camu’s berry-like fruit is widely consumed by the native people of the Amazon. Its distinguished richness in vitamin C, as …

Assessing The Anthropogenic Footprint On The Channel Sinuosity Of The Rio Grande The Delta, Edoardo Davila

Theses and Dissertations

The Rio Grande has been an emblematic feature and a source of life for the Rio Grande Valley. Since Pre-Historic times, it has provided the resources that allowed communities to thrive in a land where water is scarce. Large scale anthropogenic activities including, primarily in the form of river diversions and dam construction, have negatively impacted the river. Twenty-three major dams, and many small ones built on the main channel and many of its tributaries in the last century, have drastically reduced water discharge and virtually eliminated sediment delivery to the delta. This study explores how the channel sinuosity …

Assessing Long-Term Coral Coverage At East And West Flower Garden Banks, Rebekah Alicia Hernandez

Theses and Dissertations

Coral reefs provide critical habitat for diverse benthic communities; however, more than 10% of existing reefs have been lost as a result of natural and anthropogenic stressors. While there has been a decline in reefs around the world, East and West Flower Garden Banks (FGBs), part of Flower Garden Banks National Marine Sanctuary (FGBNMS), have maintained > 50% live coral cover for over 27 years as revealed by the FGBNMS long-term monitoring (LTM) program. In the 1980’s, the LTM program at East and West FGBs was developed in response to the expansion of oil and gas exploration, anchoring, and fishing impacts …

Biochar Applications To The Remediation Of Lead And Polychlorinated Biphenyl Contaminated Water, Victory Itua Igberase

Theses and Dissertations

This study investigated the performance of biochar materials as adsorbents to remove Pb and polychlorinated biphenyl (PCB) in aqueous solutions. Batch adsorption and column experiment packed with biochar and geomaterials (pumice) in 1:1 volume ratio was evaluated to address the efficacy of biochar in removing Pb while only batch adsorption was employed for PCB removal with biochar materials. Overall, PT biochars performed the best (42–53 mg g−1) followed by BE biochars (10–32 mg g−1) and AB biochars (17–27 mg g−1) while high temperature biochars were favored in terms of maximum Pb adsorption capacity. Column Pb breakthrough showed similar results, with …

Effects Of Saltatory Rewards And Generalized Advantage Estimation On Reference-Based Deep Reinforcement Learning Of Humanlike Motions, Md Rysul Kabir

Theses and Dissertations

In the application of learning physics-based character skills, deep reinforcement learning (DRL) can lead to slow convergence and local optimum solutions during the training process of a reinforcement learning (RL) agent. With the presence of an environment with reward saltation, we can easily plan to magnify those saltatory rewards with the perspective of sample usage to increase the experience pool of an agent during this training process. In our work, we have proposed two modified algorithms. The first one is the addition of a parameter based reward optimization process to magnify the saltatory rewards and thus increasing an agent’s utilization …