Digital Commons Network^™

Enabling High Quality Oxygen Measurements During Robotic Based Studies Of Ocean Ecological And Biogeochemical Processes, Brianna A. Alanis

Theses and Dissertations

Dissolved oxygen is an essential parameter necessary for understanding marine ecological and biogeochemical processes. New robotic vehicles and autonomous platforms are being applied to an even wider range of ecological and biogeochemical studies. Thus, arises the opportunity for matching the best possible oxygen sensing techniques and methods to these new platforms. In so doing, we can enable both more targeted and higher resolution oxygen measurements than previously possible and potentially use oxygen measurements for a wider range of applications, including in situ incubation experiments and primary productivity measurements. This thesis tested three different oxygen sensors in a trade study for …

The Role Of Sediment Resuspension In Estuarine Inorganic Nutrient Cycling, Kirsten Jo Ayres

Theses and Dissertations

Time-scaling of estuarine inorganic nitrogen cycling contains many assumptions due to biogeochemical interactions. Nitrogen, often a limiting factor for primary production, is transformed and utilized by many estuarine organisms. Inorganic nitrogen is especially high in porewater. High nutrient pore water, contained within the interstitial spaces of sediment, has been assumed to influx high concentrations of inorganic nutrients into surface waters during resuspension events. These short-term resuspension events rapidly introducing high concentration of nutrients into the water column. In order to determine the internal time scale of inorganic nitrogen cycling, a box-model nutrient budget, horizontal in situ transects, and vertical nutrient …

Learning To Detect Pedestrians By Watching Videos, Andrew Y. Chen

Theses and Dissertations

The field of deep learning has experienced a resurgence in the recent years, particularly resulting with the advent of AlexNet. Supervised learning is currently the most common and practical machine learning method. The struggle with employing supervised learning to approach problems is that it requires training data. Sufficient training data is correlated with performance for deep learning models. The issue is that preparing the training data can be a tedious and labor intensive task, especially on a large scale. The purpose of this paper is to determine how efficient a machine can learn when trained on automatically annotated data. The …

Viability Of Wetland Crops For Use In Treatment Wetlands: Nitrogen Removal From Water And Production Of Food, Andrew Denson Corder

Theses and Dissertations

Treatment wetlands are used to treat wastewater from a variety of sources, but their functionality depends on the macrophytes present therein. To better understand the viability of wetland macrophytes both as sources of food and as agents of nitrogen removal from wastewater, this study quantified plant growth, food production, and nitrogen removal capacity of three common wetland crops as well as three locally dominant graminoid species in a variety of relevant ecological contexts. All six plant species and a control were grown over a ten-week period in three related experiments: (1) under three moisture regimes, (2) with or without competition …

Comparison Of Rl Algorithms For Learning To Learn Problems, Adolfo Gonzalez Iii

Theses and Dissertations

Machine learning has been applied to many different problems successfully due to the expressiveness of neural networks and simplicity of first order optimization algorithms. The latter being a vital piece needed for training large neural networks efficiently. Many of these algorithms were produced with behavior produced by experiments and intuition. An interesting question that comes to mind is that rather than observing and then designing algorithms with beneficial behaviors, can these algorithms be learned through a reinforcement learning by modeling optimization as a game. This paper explores several reinforcement learning algorithms which are applied to learn policies suited for optimization.

Histological Evidence Of Annual And Lunar Reproductive Rhythms Of Atlantic Sea Urchin, Arbacia Punctulata In The Gulf Of Mexico: Changes In Nutritive Phagocytes In Relation To Gametogenesis, Eleazar Hernandez Ii

Theses and Dissertations

Environmental phenomena such as temperature, photoperiod, tidal cycle, and lunar rhythm act as external cues that stimulate the reproductive activity of marine organisms. In this study, I report the annual and lunar reproductive cycles, and changes in nutritive phagocytes (NPs) in relation to gonadal maturation of Atlantic sea urchin (Arbacia punctulata, a primeval species). Monthly and weekly changes in gonadal development/maturation were observed histologically. In male, the testicular lobules were densely packed with sperm from June to August. In female, on the other hand, mature eggs first appeared in some ovaries in May, numerically increased from June to …

Constructing Associative Rings From Certain Hypergroups, Oscar Gonzalez

Theses and Dissertations

Tight hypergroups give rise to associative rings if the so-called general normality condition holds\cite{ARTICLE:1}. We consider four examples of tight hypergroups which do not satisfy the general normality condition and show that they still give rise to associative rings. Our examples are HM332(24),HM10353(32), HM10933(32) and HM10941(32)[1].

Photocatalytic Degradation Of Simazine Under Visible Light Using Zinc Oxide/Molybdenum Disulfide Heterostructures, Alexandria Castillo

Theses and Dissertations

The photocatalytic degradation of simazine under visible light by using ZnO/MoS2 heterostructures was investigated. Reaction parameters studied to optimize simazine degradation included pH, loading mass of the photocatalyst, and percentage of MoS2 in the heterostructure. pH 2 was the optimal environment for the degradation reaction of all catalysts. A loading mass of 20 mg for each of the ZnO/MoS2 photocatalysts was determined to be the most effective for in the degradation process. The degradation reactions were observed to follow 2nd order kinetics for all photocatalysts at all temperatures. Band gap studies confirmed a lower energy than that of pure ZnO …

A Sinking Feeling: The Fate Of Concrete Pyramids Deployed In Artificial Reefs In The Texas Gulf Of Mexico, Cameron J. Moody

Theses and Dissertations

The deployment of 2,611 concrete pyramids in Texas gulf waters represents a significant undertaking. In collaboration with Texas Parks and Wildlife, bathymetric sidescan data was collected at three reefs hit by Hurricane Harvey from 2017 to 2019. All reefs lost significant pyramid height between 2017 and 2019. The pyramids demonstrated greater subsidence in the year when Harvey occurred and minimal subsidence the following year. Pyramids that moved outside the reefs were due to hurricane forces and shrimp trawl activity. Pyramids that remained inside the reef remained at their deployment location for two reefs. The pyramids remaining in the third reef …

Identifying The N Sources For Black Mangrove (Avicennia Germinans) In A South Texas Mangrove Forest, Ashley Elizabeth Murphy

Theses and Dissertations

Black mangrove (Avicennia germinans) in south Texas provide ecosystem services and benefits to humans including: habitat for wildlife, prevention of coastline erosion, and mitigation of natural disasters. One step to preserve their ecological functions is to identify and protect the source of their nitrogen (N). Nitrogen stable isotopes were sampled for one year beginning August 2018 and used as tracers to identify how mangroves obtain N. Total N in (A. germinans) and associated (Batis maritima) (plants) (2.1%) was more abundant than in cyanobacteria (0.6%) and sediment (0.1%). Plant d15N signatures (5.52‰) were more similar to sediment (5.21‰) than cyanobacteria (1.98‰), …

Dna Barcoding Reveals Unexpected Diversity In Octocorallia In The Northwestern Gulf Of Mexico, Chelsea L. Pavliska

Theses and Dissertations

Coral reefs are an integral tier of marine ecosystems. They provide habitat and foraging opportunities for many ecologically and economically important fishes. Protection of coral reef biodiversity and connectivity is imperative to the continued health and sustainability of marine fisheries. Mesophotic reefs, such as those found in the northwest Gulf of Mexico, have unique coral communities because of the limited light penetration at mesophotic depths (30 – 150m). Because there is limited knowledge in regards to the biodiversity of coral reefs of the northwestern Gulf of Mexico (GOM), particularly the South Texas Banks (STBs), thesis work presented here aims to …

Detecting Phone-Related Pedestrian Behavior Using A Two-Branch Convolutional Neural Network, Humberto Saenz

Theses and Dissertations

With the wide use of smart phones, distraction has become a major safety concern to roadway users. The distracted phone-use behaviors among pedestrians, like Texting, Game Playing and Phone Calls, have caused increasing fatalities and serious injuries. With the increasing usage of driver monitor systems on intelligent vehicles, distracted driver behaviors can be efficiently detected and warned. However, the research of phone-related distracted behavior by pedestrians has not been systemically studied. It is desired to improve both the driving and pedestrian safety by automatically discovering the phone-related pedestrian distracted behaviors. In this thesis, we propose a new computer vision-based method …

A Landscape-Scaled And Community Ecology Approach To Wildlife Corridor Design In South Texas, James A. Stilley

Theses and Dissertations

A formidable challenge in landscape ecology is developing a sound resolution to mitigate the impacts of habitat fragmentation and restore connectivity to a degraded landscape. The problem is worldwide landscapes are becoming primarily anthropogenic and areas set aside for wildlife are small and isolated. Researchers’ have developed the concept of the wildlife corridor to mediate this situation but a proper methodology to implement this concept is still in its infancy. This study aims to uncover a quantitative and repeatable wildlife corridor design methodology based on the least cost analysis strategy with both a singular focal taxa approach and a comprehensive …

Organic-Inorganic Hybrid Materials For Piezoelectric/Triboelectric Nanogenerator, Aminur Rashid Chowdhury

Theses and Dissertations

Nanogenerator has been a major focus among researchers of recent time due to its versatile use in everyday life. Though the discovery of the piezoelectricity and the triboelectricity dates back to 19th century, the use of these phenomena has not been in practical use till 2006. In this study we demonstrate the practical application of piezoelectric and triboelectric nanogenerator comprised of different copolymer and piezoelectric ceramic. The largely known piezoelectric polymer Polyvinylidene fluoride (PVDF) has also been utilized. The enhancement of piezoelectric properties of PVDF has been achieved by utilizing surface activation of accommodating ceramic. The Li doped ZnO has …

Evaluating Responses Of Benthic Macrofauna To Artificial Reef Presence In The Gulf Of Mexico, Douglas Faircloth

Theses and Dissertations

Artificial reef research has long concerned itself with the interactions of fishes and has tended to favor commercially valuable species. Because of this, a larger yet less known group that heavily benefits fishes have been overlooked; benthic macrofauna. Benthic macrofauna are marine invertebrates that live below the sediment-water interface and play many roles in the ecosystem. Macrofauna are important prey items, ecosystem engineers, and bioindicators, as well as being ubiquitous in the marine environment. Since macrofauna have been largely ignored in this field, not much is known regarding their interaction with the placement of artificial reefs. To try and fill …

Developing Multispectral Imaging Techniques To Determine Canopy Coverage And Carbon Storage Of Seagrasses In The Gulf Of Mexico, Ivy Michelle Hinson

Theses and Dissertations

Although seagrass beds provide global ecosystem services, coverage is in rapid decline, with the capacity of seagrasses to sequester carbon of special concern. Current seagrass monitoring methods are labor intensive and may not offer a complete picture of coverage. Remote sensing offers the ability to oversee landscapes but water in coastal environments presents challenges, as the commonly used near-infrared wavelength dissipates in water.

This project aimed to provide reliable methodology to assess seagrass coverage using multispectral imagery taken from an unmanned aerial vehicle and to provide evidence for the link between seagrass coverage and stored belowground carbon for common seagrasses …

2-Hyponormality On Unilateral Weighted Shifts, Juan G. Benitez

Theses and Dissertations

Given the concept of a normal operator, several weaker notions have been proposed in order to extend the properties of normal operators to a wider range of operators. One such notion is that of k-hyponormal operators. In this document, we focus our attention on the 2-hyponormality of weighted shift operators over a discrete Hilbert space. It will be shown that if a certain relation between the weights α = ( α0, α1,...) of a weighted shift Wα is satisfied, then the 2-hyponormality of Wα implies the hyponormality of Wαm for any m = 2, 3,....

A Search For A High-Order Excitation Of Surface Phonon Polaritons On Silicon Carbide Metasurfaces, Md Litan Ali

Theses and Dissertations

Metasurfaces promise a control of light in free and confined spaces like optical waveguides using subwavelength-scale nanostructures. In this work, we experimentally investigate a variety control of light in more confined spaces which is localized surface waves of light. A control of surface waves has been challenged because of a lack of efficient nanostructures. For example, conventional and widely used metallic nanostructures have a high coupling efficiency of light due to free charge carriers but the charge carriers induce a high optical power loss. We recently designed and fabricated metal/dielectric multilayer aperture on ionic crystal, which shows a strong resonance …

Enhancing Transport In Classical And Quantum Systems Using Non-Hermiticity, Fatemeh Mostafavi

Theses and Dissertations

Non-Hermiticity, the presence of gain and loss in the structures, provides a flexible platform to utilize the wave propagation in classical and quantum system. Here in this thesis by using this advantage we aim to enhance the transport in both realms.

Pipeline For Variable Star Detection And Eclipsing Binary Characterization, Moises Castillo

Theses and Dissertations

Stars have been observed and recorded since ancient times. Practices of documenting brightness led to observations of variability. Optical CCD observations of eclipsing binary stars were made with instruments at UTRGV Dr. Cristina Valeria Torres Memorial Astronomical Observatory. There are two main goals for this project. The first goal is to create a pipeline written in python (lightcurator) that creates a framework for detecting variable stars. The pipeline starts by creating a list of ccd frames written in FITS format of an eclipsing binary star observation. These object frames are expected to be already reduced, but lightcurator provides tools to …

Empirical Bayes Estimators And Borel-Tanner Distribution, Celestina Ruby Soltero

Theses and Dissertations

The motivation for this paper stems from the role Borel-Tanner (BT) distribution has as the distribution of the total outbreak number in epidemics modeled by branching processes. We briefly review Borel-Tanner distribution and its applications. In Chapter II we outline the Bayes decision problem, a construction for an Empirical Bayes (EB) estimator proposed by Liang [9] and discuss risk analysis. In Chapter III, the importance of randomization addressed and a classical construction of a monotonized EB estimator proposed by Houwalingen [14] is outlined. Lastly in Chapter IV we use R software to perform a Monte Carlo simulation and conduct a …

Removal Of As (Iii) And As (V) From Potable Water Using Zno Nanoparticles, Grecia Torreblanca Baez

Theses and Dissertations

Heavy metal and toxic element contamination of the environment has been increasing with increasing industrialization. Arsenic has become an element of particular concern because of its toxicity, which is oxidation state dependent. As(III) is observed to be much more toxic than As(V), as well the removal is more difficult than As(V) in traditional water treatment technology. In the present study, As (III) and As(V) removal was investigated using a zinc oxide nanomaterial that was synthesized using a titration/precipitation technique, and characterized using powder x-ray diffraction. In the present study, the kinetics of adsorption, the adsorption isotherms as well as the …

Analysis Of The Cnn Algorithm In Target Recognition By Using The Mstar Database, Ligang Zou

Theses and Dissertations

With the rapid development of artificial intelligence technology and the emergence of a large number of innovative theories, the concept of deep learning is widely used in object detection, speech recognition, language translation and other fields. One of the important practices is target recognition in SAR images. Although it shows certain effectiveness in some researches, when using deep learning algorithm, there are still many problems that have not yet been solved. For example, people do not have a good understanding of how convolution works and the impact of convolution on the algorithm, although convolution works well in the CNN algorithm. …

The Conical Diffraction And Adiabatic Elimination In Pt-Symmetric Systems, Mojgan Dehghani

Theses and Dissertations

Dehghani, Mojgan, The Conical Diffraction and Adiabatic Elimination in PT-Symmetric Systems. Master of Science (MS), July, 2019, 75 pp., 32 figures, references, 69 titles. Since almost two decades ago, the non-Hermitian Hamiltonians with combined parity and time-reversal symmetry, having entirely real spectra, have been outstanding candidates for characterizing the features of open systems. In this thesis, we investigate the dynamics of certain PT systems. In chapter I, we present a brief review of the fundamentals of PT-symmetric systems. Chapter II focuses on the conical diffraction in a PT-symmetric waveguide lattice. We explore the evolution of a wave packet, which forms …

Reduction Of The Kp Hierarchy, Adrian Eugenio Torres

Theses and Dissertations

This thesis will delve into the Kadomtsev-Petviashvili equation or KP equation and it's hierarchy. More specifically, the solition theory around it. To do so, we first explore the soliton theory for the Korteweg de-Vries equation or KdV equation by analysing it through the inverse scattering transform method and presenting it's soliton solutions. Second, we will introduce, Hirota's bilinear form, and understand its main idea. Third, introduce Sato Theory, and use it to formulate the KP hierarchy, via using pseudo-differential operators, presenting the lax operator, the dressing operator, Sato’s equation, and the zero curvature equation (Zakharov-Shabat Equation). Fourth, find the general …

Bubble Nucleation And Cooperativity In Duplex Stretching Of A Helicoidal Dna Model, Pawan Kumar Thapaliya

Theses and Dissertations

Denaturation of DNA means separation of dsDNA into ssDNA due to the breaking of hydrogen bond by the application of heat or another mechanical method to carry out the processes like translation,transcription, and replication. Single-molecule DNA stretching experiments displayed a force-induced transition at a force of 65pN for long dsDNA molecules. In these experiments, double stranded DNA molecules are stretched by a force applied to opposite ends of the DNA, e.g., in anatomic force microscope or an optical tweezers instrument. Here we study the thermal and force-induced denaturation of the helicoidal DNA bubble-in-the middle sequence by Monte-Carlo simulations technique. We …

Engineered Porous Media For Groundwater Contaminant Remediation: Applications Of Nano-Tio2, Sheng Yin

Theses and Dissertations

Nonmetallic Arsenic and hydrocarbon BTEX are the most common and harmful contaminants in groundwater. Many oxide, biological and metal based adsorbent materials have been investigated in the laboratory and in the field environment. These materials, especially for nano-TiO2, have been extensively studied in the laboratory due to its high efficiency and remediation outcomes. This research compared two different synthetic nano-TiO2, aggregated dendritic nano-scale anatase TiO2 and the polymorphed rutile nano-TiO2 attached to the surface of SiO2, to study the feasibility of nano-TiO2 in geoenvironmental engineering applications. Characterization of crystal structure, purity, and morphologic, microscopic features of the materials were examed …

Mobile Solar Energy Environmental Control System With Remote Accessibility, Luis S. Garay

Theses and Dissertations

The proposed system, Mobile Solar Energy Environmental Control System with Remote Accessibility (mSEECS w/ RA), is based on the utilization of an already available Energy Storage Unit (ESU) in a Transport Unit System (TUS) to harness solar energy to provide a system to enhance the environment, safety and security of a TUS in a stationary or a mobile state by monitoring and controlling the operation of its onboard systems, and provide remote accessibility to know the state of affairs at any time. To relate to a real world application, the battery (ESU) of a vehicle (TUS) is underutilized …

Effects Of Elevated Temperature On Gonadal Functions, Cellular Apoptosis, And Oxidative Stress In Atlantic Sea Urchin (Arbacia Punctulata), Jackson B. Johnstone

Theses and Dissertations

Increasing surface sea water temperatures effect on growth, reproduction and development in marine organisms. Sea urchins are excellent indicator species and ideal model organisms to focus on. In this study, I tested the effect of higher temperatures on reproductive functions, heat shock protein (HSP, a chaperone protein produced by cells in response to heat stress) and nitrotyrosine protein (NTP, an indicator of reactive nitrogen species, RNS) expressions, cellular apoptosis, and ceolomic fluid (CF, a body fluid which regulates important physiological processes) conditions in Atlantic sea urchin at three different temperatures. Ten sea urchins were placed in each of six aquariums …

Object Enhancement, Noise Reduction, Conversion And Collection Of Spatiotemporal Image Data, Michael Izaguirre Jr.

Theses and Dissertations

In this report, a variety of cellular dynamics are enhanced and analyzed utilizing various algorithms and filter for contrast enhancement. This report will also illustrate the underlying complexities of processing compressed data received from certain type of sensors, their default applications, various methods in converting compressed data to compatible universal uncompressed formats allowed in scientific applications, various methods of image and video capture, guidelines in ethical image manipulation, various methods of frame extraction, and analyzing/processing video images. These methods and processes purposely utilize freeware and public domain software to lower the cost of reproducibility for all.