Digital Commons Network^™

Developing A Prototype Energy Harvesting Device For Powering Wireless Onboard Condition Monitoring Sensor Modules For Railway Service, Martin Amaro Jr.

Theses and Dissertations

An energy harvesting system is being developed to power a wireless bearing health monitoring device. In contrast to other monitoring systems, this wireless monitoring device is a low-powered onboard solution. Powered by a 3.7-Volt lithium-ion battery, the device can continuously function for several months on a single charge. By implementing an energy harvesting system, the life of the battery can be increased reducing the overall maintenance, electronic waste, and time needed to replace the batteries. The harvesting system uses thermoelectric generators to convert the heat generated in the bearings into electricity. The system is composed of aluminum heat sinks, a …

The Relationship Between Mindfulness, Social Anxiety Traits, And Emotions, Maria Jackeline Diaz

Theses and Dissertations

The relationship between mindfulness, social anxiety traits, and emotion processing is the first study of its kind to be looked over. In this study we will assess similarities and differences, plus how they work together to provide further research and understanding of these complexities when combined. Such research can be helpful in making us understand our emotions, as well as how our emotions can be perceived in social functioning and communication.

A Gis-Based Model To Assess On-Site Sewage Facility (Ossf) Contamination Risk To Local Water Resources, Alvaro Garcia

Theses and Dissertations

In a collaborative effort between Texas Water Resources Institute (TWRI), Cameron County Public Health (CCPH), Texas A&M AgriLife Extension (TAMAE), and the University of Texas Rio Grande Valley (UTRGV), a GIS database that includes relevant OSSF information, such as location, system age, lot size, and other important parameters was created.

This OSSF database, along with publicly available GIS data, was used to create an integrative GIS-based risk assessment model where OSSF risk parameters were assigned a risk factor and combined into a spatial contamination risk for surrounding areas and their receiving waterbodies. Parameters were broken down into two categories: environmental …

Ad Infinitum: The Bourgeois Construction Of An American Lady, Miriam M. Cepeda

Theses and Dissertations

This thesis explores the emergence of the Bourgeois culture in Antebellum America during the transition of nineteenth century America into what we refer to as “modern-day America.” This period is crucial in American history as ideological concepts developed as the nation industrialized, thus creating the nation’s identity. In doing so, gender roles were voraciously prescribed with a focus on women’s sexuality as a focal point for Victorian discourse. Unlike prior to the Revolution, which gender roles were previously assumed, by the mid-nineteenth century, modes of surveillance are apparent in sermons, medical treatises, Victorian periodicals and literature, in which ideological productions …

Smart Metering Communication Protocols And Performance Under Cyber Security Vulnerabilities, Oscar A. Alvarez

Theses and Dissertations

The communication process is the key that characterizes the modern concept of smart grid, a new technology that introduced a “two-way communication” in energy measurement systems and can be best represented through the smart meters. Hence, the goal of smart metering communication is to ensure a secure and reliable transmission of information that can only be accessed by end users and energy supplying companies. With the goal of improving the information security in smart energy grids, the research presented in this work focused on studying different advanced metering infrastructure communication protocols and, it showcases a series of experiments performed on …

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 …

A Hispanic-Serving Institution, Its Strategic Human Capital Utilization And The Shift In Institutional Culture After The Merger, Trini Yunes

Theses and Dissertations

In the United States, there has been recent attention to mergers involving higher education institutions. The fact is that mergers and acquisitions (M&A) are not a novel topic but more common in business. The paper will present the findings of a case study of the merger of two Hispanic-Serving Institutions (HSIs) in Texas and how leadership used both legacy cultures to create a new organizational culture. The main focus of this study is to compare the relationships, as viewed by staff and faculty, between institutional performance and organizational culture. It will also determine how human capital (HC) utilization is related …

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 …

Exploring The Role Of Stigmatic Exudate In The Water Lily (Nymphaceae) Pollination Mechanism Using N. Ampla (Salisb. Dc.), Luis Uribe

Theses and Dissertations

Water lilies are the only known plant group that uses hyperactive nectar glands to divest pollinators of their pollen. The nectar in Nymphaea ampla is thought to contain secondary metabolites that increase pollen deposition possibly by modifying pollinator behavior. This was explored utilizing visitation and fecundity data from the field coupled with survival and behavioral experiments in the laboratory. Replacing nectar with water reduced seed set in N. ampla which was attributed to reduced visitation in water-bearing flowers and not to effects on pollinator detention time. Exposure to nectar did not reduce survivability in Apis mellifera. Pollen and nectar foragers …

To A More Sustainable Construction Method For Electrically Conductive Heated Pavement Systems, Mohammad Anis

Theses and Dissertations

Snow and ice damage to the pavement in the United States, particularly in colder regions, costs the US economy millions of dollars each year. Conventional methods for keeping snow off roads after heavy snowfall are judged prohibitively expensive. As a result, an alternative solution is required to reduce costs while also improving pavement resiliency. An electrically heated pavement system (EHPS) has been regarded as a viable alternative to older approaches in recent years. The majority of earlier research concentrated on improving the conductivity characteristics of paving materials. On the other hand, this study takes a different approach by focusing on …

The Skeletal Structure Of Hot Mix Asphalt And The Effects Of Fiber Additives, Samantha A. Avila

Theses and Dissertations

Hot mix asphalt (HMA) has proven to be successful in providing a proper paving surface for transportation services throughout the world. Asphalt pavement could be altered as the gradation of the mixture is adjusted. For instance, mixtures could vary from Dense Graded (DG) that contain a fairly even percentage of all aggregate size allowing for a more compact fit to Stone Matrix Asphalt (SMA) where the coarse aggregate compromise the main skeleton while fine aggregate fills the voids. This study investigates the effects of fibers and skeletal structures on mechanical properties of HMA. Two types of fiber additives are tested …

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 …

Bullet-Proof Boll Weevil: The History Of Boll Weevil Eradication, Evan A. Berg

Theses and Dissertations

Farmers and entomologists have all experimented with various methods to find the best way to defeat the United States' boll weevil. The techniques themselves, while expansive, can be examined within the scope of the years that they were used. This provides an exciting insight into how cotton pest management became more complex as the decades moved on and revealed how the science of cotton pest management evolved to deal with the boll weevil and other future cotton threats.

Synthesis And Characterization Of Copper Oxide Nanofibers, Shishir Barai

Theses and Dissertations

The aim of this study was to develop polymer-derived Copper (II) Oxide (CuO) nanofibers through centrifugal spinning technique and subsequent calcining. To obtain the force spun pre-ceramic copper acetate nanofibers, 15% wt, 25% wt, 35% wt, 50% wt% copper acetate (active material) and poly (vinyl) alcohol ( PVA) solutions was prepared with deionized water (DI) as solvent and spun at 7500 rpm in a FibeRio Cyclone. Thermogravimetric analysis (TGA) was implemented to determine the thermal degradation behavior of the pre-ceramic nanofibers. These nanofibers were then calcined at three different temperatures (500, 600 and 700°C) to produce CuO nanofibers. The microstructure, …

Evolutionary Development Study Of Firebrat (Thermobia Domestica), Luis Cantu Jr.

Theses and Dissertations

As most evolutionary development studies regarding wing origin take place using insects taxonomically closer to model organism, Drosophila melanogaster, there is a need of expanding studies to lower clades. While D. melanogaster is higher phylogenetically, basal clades would allow for a historical perspective of what occurs within the gene flow of conservative biomarkers. Further understanding of wings and flight would allow for a clearer understanding of how the migration of insects from sea to land has allowed them to become one of the most speciose taxa. Through the study of Thermobia Domestica, part of the Zygentoma, we expand on comprehension …

Assessing The Effectiveness And Efficacy Of Wireless Onboard Condition Monitoring Modules In Identifying Defects In Railroad Rolling Stock, Lee R. Cantu

Theses and Dissertations

Many industries have begun shifting into the Internet of Things (IoT) in the 21st century. To help ease this transition for the rail industry, The University Transportation Center for Railway Safety (UTCRS) has partnered with Hum Industrial Technology, Inc. (HUM) to help complete the development of a Wireless Onboard Condition Monitoring system named the ‘Boomerang™’. This product allows customers to schedule proactive maintenance on their railcars to replace defective wheels and/or bearings, saving them time, money and potentially preventing costly catastrophic derailments. The UTCRS research team has established thresholds to determine defective bearings utilizing thermal and mechanical sensors.

The effectiveness …

Lubrication Performance Of Vegetable Oils Modified With Halloysite Clay Nanotubes (Hnt) As Lubricant Additives, Md Abu Sayeed Biswas

Theses and Dissertations

Vegetable oil-based nano-lubricants are a great alternative to petroleum-based lubricants because of their less adverse impact on the environment. This work evaluates the tribological performance of sunflower, corn, and peanut oils modified with halloysite clay nanotubes (Al2Si2O2(OH)2nH2O) as lubricant additives at different concentrations. To analyze the tribological performance of the nano-lubricants, a block-on-ring tribometer was used following the ASTM G-077-17 standard procedure. Characterization of HNT was carried out by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Thermogravimetric Analysis (TGA). The effect of the HNT on the lubrication performance of the newly developed vegetable oil-based nano-lubricants was evaluated, and the …

Latinas And Service-Learning In Higher Education: Voices, Experiences And Perspectives, Maria Cristina Cantu-Gutierrez

Theses and Dissertations

This is an exploratory case study that explored service-learning experiences and perceptions among Latinas enrolled in a South Texas university. This study also addresses the challenges and benefits that are associated with Latinas and service-learning in higher education as service providers. This study provides a better understanding of Latina students' experiences and perceptions of their involvement in providing services within their Latino community.

Exploring Self-Perceived Employability In People With Disabilities And Other Intersecting Identities, Kerra Lajoy Daniel

Theses and Dissertations

People with disabilities are the largest minority group in the world representing 26% of the world’s population. More specifically, in the U.S. 61 million Americans have a diagnosed disability. However, intersectionality studies have not been inclusive of this particular population and disability studies have yet to extensively examine intersectionality in PWDs. Centering individuals with disabilities who also identify with multiple marginalized social identities , such as being a woman, a person of color or a member of the LGBT community is important since these individuals’ experiences are not uniform in nature. PWDs experience higher rates of discrimination, unemployment, and …

Synthesize And Characterization Of Aluminum- Tungsten Carbide Nanocomposite, Shuvendu Das

Theses and Dissertations

This research focuses on developing metal matrix composite reinforced by polymer-derived ceramic fibers. The force-spun AMT nanofibers were heat treated into tungsten carbide and then mixed with aluminum powder using cold pressing and sintering to produce the composites. The basic mechanical properties of this composite are investigated by density measurement, hardness and compression testing. SEM, EDS and XRD were used to test the morphology of tungsten carbide fibers. EDS identified a near-perfect W-C ratio in tungsten carbide fibers 1000 °C. Tungsten Carbide fibers were crushed using ball milling technique. Tungsten carbide nanofibers powder had a variety of particle size. Results …

Latino/A Student Perspectives On Literacy Practices Affecting College Readiness, Danira Vanessa Cantu

Theses and Dissertations

This qualitative collective case study examines how pre-collegiate literacy practices affect Latino/a student college success. Conducted at a South Texas border-region University, this study utilized a sample of six Latino/a students enrolled in a freshman level composition course. A focus group was used to explore how academic and social literacy practices play a part in college readiness for these transitioning college students. Additionally, personal narratives were conducted as a form of counternarrative. Modeled on the theoretical framework of removing racism from school structures and closing race-related academic divides, findings included the need for social and cultural acceptance, classroom adaptability, and …

Intimate Partner Violence In The Rio Grande Valley: The Role Of Culture, Tania Diaz

Theses and Dissertations

Mexican culture along the border towns of the Rio Grande dominates views towards women and men experiencing violence in intimate relationships. However, there is a paucity of empirical studies relating to intimate partner violence in the Rio Grande Valley. This study addresses the dynamics of abusive relationship in a Hispanic community that can be influenced by cultural concepts such as familism and marianismo. The author utilized a mixed methods approach for this study that included a sample of (n = 513) surveys and (n = 13) interviews that were analyzed separately. Multivariate logistic regression analysis was used to assess …

Molecular Dynamics Study Of Atomic Diffusion In Cantor High Entropy Alloy In The Selective Laser Melting Process, Mathew Z. Farias

Theses and Dissertations

High entropy alloys (HEAs) are compositionally complex alloys that are comprised of 5 or more principle elements at near equimolar concentrations. The Selective Laser Melting (SLM) method generally melts pure elemental powders or prefabricated alloy powders, this process allows for the production of heterogeneous structures that would be difficult to create through more conventional means. In-situ alloying in SLM, or Laser Additive Alloying (LAA), using pure elemental powders is a promising means of producing what would otherwise be costly and difficult to fabricate products with less defects using prefabricated powders, therefore this new approach could enable the ability to …

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 …

Characterization Of Soil Nematode Community As Influenced By Weedy Plants And Edaphic Properties, Orlando Garcia

Theses and Dissertations

Nematodes are one of the most critical species globally as they are part of most nutrient recycling. While nematodes play a vital role in nutrient cycling, little is known about them from an ecological standpoint. The majority of current research has focused on a singular component of the community, being those of herbivore/plant-parasitic nematodes. In this study, the community shifts of the nematode trophic groups were analyzed as influenced by native and invasive grasses species in the Lower Rio Grande Valley (LRGV) with the addition of edaphic soil properties.

In our study, the results indicate changes in the composition of …

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 …

The Journey Of Selected Latina Transnational Educational Leaders: Transforming Their Lives Through Educational Achievements And Successful Careers, Raquel Garcia

Theses and Dissertations

The purpose of this study was to examine the journeys of selected Latina transnationals and how they transformed their lives through educational achievements and successful careers in the borderlands of Texas. The researcher utilized a phenomenological collective case study approach that investigated how the selected Latina transnationals overcame challenges via a series of semi-structured interviews (Creswell, 2013). Latinas are forced through their journeys to negotiate multiple systems that could possibly impact their educational trajectories (Lechuga-Pena & Lechuga, 2018). Despite Latinas being seen as the other, the object, the minority, many are able to tell their own stories and liberate themselves …

Life-Cycle Cost Analysis Of The Efficient Water Fixtures And Electric Appliances Used To Minimize Water And Energy Consumption In Homes In The U.S, Miranda N. Garcia

Theses and Dissertations

Consumer interest in incorporating sustainability and efficient appliances into daily life has been growing in the past several years. While reducing their environmental impact may be a draw to some, by making the switch to water- and energy-efficient appliances many homeowners are enticed by the promise of long-term savings on utility bills. Programs such as WaterSense and Energy Star not only offer certified efficient appliances and fixtures, but they may also certify water- and energy-efficient homes. Additionally, the United States Green Building Council (USGBC) offers the LEED program (Leadership in Energy and Environmental Design) which certifies homes in a similar …

Cowboy Conversations, Abraham Garza

Theses and Dissertations

I have always had a profound interest in the past; how that past affects the present, and ultimately, anticipating how the present will affect the future. Circumstances change, but the lessons we’ve learned will, inevitably, determine how we handle impending events. Using fiction as a platform, my intent is to reveal, through each chapter, how one’s past dictates future decisions.

I have been working with a vaquero, my wife’s grandfather, who was raised on different South Texas ranches. Taking odd jobs from stall boy to ranch hand, and horse trainer, his unique experiences will illustrate period-based scenarios that emphasize his …