Digital Commons Network^™

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 …

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 …

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 …

Factors Affecting Irs Audit Rate Probability: Empirical Evidence From Rgv Region, Issack Guyo

Theses and Dissertations

IRS tax audits are intended to curb tax evasion; however, they are costly to conduct and have negative impacts on taxpayers. The purpose of this study is to find out factors that lead to high IRS audit rate in a region from the perspective of the Rio Grande Valley (RGV). Relationship between IRS tax audit rate and determinants of tax evasion identified by Davis, Cebula, & Boylan (2020) among others are studied. A regression analysis is conducted on the regions scores on poverty rate, demography, unemployment rate and general level of education with the IRS audit rate. The results suggest …

Data Analytics For Google Trend Search Result Of Illness Symptoms, Md Jakir Hossain

Theses and Dissertations

The outbreak of COVID-19 has escalated from March 2020. Since then, people from all over the world are curiously searching different types of illness symptoms including corona virus. Before the outbreak, people were also searching different types of symptoms at different times. Both diseases share same symptoms, but in the flu season. If certain types of symptoms are visible at summer season, then these symptoms are for corona virus. The main purpose of our study is to find out this discriminative information from these search result. We will discuss some mathematical concepts and then develop an algorithm based on those …

Factors That Contribute To Motivation And Student Achievement As Adolescents Transition From Elementary To Middle School Or Junior High In One Urban District In The Rio Grande Valley, Lizette Villarreal Longoria

Theses and Dissertations

This study will examine factors that contribute to the decline in achievement scores in reading and mathematics when students transition from elementary to their first year in middle school or junior high school. It will test the hypothesis that motivation is not a function of mentors, academic support, teams, parental involvement, transition experience, math perception, and reading perception for students transitioning from elementary to middle school or junior high school. In this quantitative research study, data will be collected using a multiple linear regression analysis to examine the factors that contribute to motivation and the achievement score decline in reading …

Understanding Teacher Perceptions And Experiences About Active Learning Techniques In High School U.S. History Courses At A Lower Rio Grande Valley School District, Juan J. Mendoza

Theses and Dissertations

This qualitative study explored the perceptions and experiences of teachers about the use of active learning techniques in high school United States history courses at a lower Rio Grande Valley school district. The study employed a phenomenology design for rich textural descriptions and a systematic exploration of the phenomenon of active learning techniques. Data were collected from individual semi-structured interviews and a focus group of 8 U.S. history teachers. Teacher lesson plans were examined to further corroborate evidence coded from the semi-structured interviews and focus group.

The research evidence suggested that active learning pedagogies create a progressive learning environment, they …

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 …

Prospecting For And Isolation Of Microalgae In South Texas, Mauricio Alejandro Peña

Theses and Dissertations

Microalgae is a very important microorganism that can be used for beneficial purposes for humans. One way to show the importance of algae in this planet is the contribution of Oxygen it provides to the atmosphere, which many organisms rely on (Medeiros et al., 2015). Carbon footprint has been one of the greatest causes for global warming and it is due to the use of fossils to create diesel. One of the ways to avoid contamination is to replace those fuels that are used on daily basis, such as for transportation. The microalgae are able to produce lipids that can …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

Reactivity Of O-Drug Bond In Some Suggested Voltarine Carriers: Semiempirical And Ab Initio Methods, Rehab M. Kubba, Mustafa M. Kadhim

Baghdad Science Journal

In this work, the possibility to use new suggested carriers (D= Aspirin, Ibuprofen, Paracetamol, Tramal) is discussed for diclofenac drug (voltarine) by using quantum mechanics calculations. The calculation methods (PM3) and (DFT) have been used for determination the reaction path of (O-D) bond rupture energies. Different groups of drugs as a carrier for diclofenac prodrugs (in a vacuum) have been used; at their optimized geometries. The calculations included the geometrical structure and some of the physical properties, in addition to the toxicity, biological activity, and NLO properties of the prodrugs, investigated using HF method. The calculations were done by Gaussian …

Useing The Hierarchical Cluster Analysis And Fuzzy Cluster Analysis Methods For Classification Of Some Hospitals In Basra, Bahaa Abdul Razaq Qasim, Shrook A. S. Al-Sabbah, Ashraf Mohammed Shareef

Baghdad Science Journal

In general, the importance of cluster analysis is that one can evaluate elements by clustering multiple homogeneous data; the main objective of this analysis is to collect the elements of a single, homogeneous group into different divisions, depending on many variables. This method of analysis is used to reduce data, generate hypotheses and test them, as well as predict and match models. The research aims to evaluate the fuzzy cluster analysis, which is a special case of cluster analysis, as well as to compare the two methods—classical and fuzzy cluster analysis. The research topic has been allocated to the government …

Exploring Teachers’ Perceptions Of Assessment Literacy In A High Performing School District In New Jersey, Marlena Celebre-Baird

Seton Hall University Dissertations and Theses (ETDs)

As teachers gain experience, their assessment knowledge base, personal beliefs, and the educational context come together to shape their identity as an assessor. Therefore, assessment literacy is not simply a stagnant knowledge base of skills but rather that takes shape over time, through reflective teaching continues to develop. This study sought to add to the body of research that highlights and describes, through the lens of the teacher, how beliefs and contextual factors influence a teachers’ assessment literacy in practice.

A qualitative case study methodology was selected for this study to explore how elementary K–5 teachers’ personal beliefs play a …

Shipboard Lidar As A Tool For Remotely Measuring The Distribution And Bulk Characteristics Of Marine Particles, Brian Leigh Collister

OES Theses and Dissertations

Light detection and ranging (lidar) can provide remote estimates of the vertical distribution of optical properties in the ocean, potentially revolutionizing our ability to characterize the spatial structure of upper ocean ecosystems. However, challenges associated with quantifying the relationship between lidar measurements and biogeochemical properties of interest have prevented its adoption for routinely mapping the vertical structure of marine ecosystems. To address this, we developed a shipboard oceanographic lidar that measures attenuation (α) and linear depolarization (δ) at scales identical to those of in-water optical and biogeochemical measurements. The instrument’s ability to resolve the distribution of optical and biogeochemical properties …

The Second-Order Impact Of Relative Power On Outcomes Of Crisis Bargaining: A Theory Of Expected Disutility And Resolve, Tatevik Movsisyan

Graduate Program in International Studies Theses & Dissertations

How does structure shape behavior and outcomes in crisis bargaining? Formal bargaining models of war rely on expected utility theory to describe first-order effects, whereby the payoffs of war determine actors’ “resolve” to fight as a function of costs and benefits. Value preferences of risk and future discounting are routinely treated as predefined and subjective individual attributes, outside the strategic context of bargaining or independent from expected utility. However, such treatment fails to account for context-conditional preferences sourcing from actors’ expectations of relative gain or loss. Drawing on a wealth of experimental evidence from behavioral economics, but without departing from …

Estimating The Risk Of Future Plastic Marine Debris Resulting From The Urban Coastal Built Environment, Kelly C. Jones

OES Theses and Dissertations

The growing urban built environment in the coastal zone poses an unknown risk to the marine biosphere as a source of marine debris. Plastic, since its introduction in the mid- 1900s, is now used in nearly all aspects of human life. Growth in human population and urbanization in coastal zones has resulted in the accumulation of large stocks of plastic in the coastal built environment, and these stocks are still growing exponentially. The coastal zone is exposed to a number of hazards including storms, tsunamis, and sea level rise, and most of these hazards are expected to change in the …

On The P-Inner Functions Of ℓPA, James G. Dragas

Mathematics & Statistics Theses & Dissertations

Define ℓ^p_A as the space of all functions holomorphic over the unit disk whose Taylor coefficients are p-summable. Despite their classical origins and simple definition, these spaces are not as well understood as one might expect. This is particularly true when compared with the Hardy spaces, which provide a useful road map for the types of questions we might consider reasonable. In this work we examine the zero sets of ℓ^p_A, p ∈ (1;∞), as well as a notion of inner function that is consistent with the approach taken on numerous other function spaces. …

Data-Driven Operational And Safety Analysis Of Emerging Shared Electric Scooter Systems, Qingyu Ma

Computational Modeling & Simulation Engineering Theses & Dissertations

The rapid rise of shared electric scooter (E-Scooter) systems offers many urban areas a new micro-mobility solution. The portable and flexible characteristics have made E-Scooters a competitive mode for short-distance trips. Compared to other modes such as bikes, E-Scooters allow riders to freely ride on different facilities such as streets, sidewalks, and bike lanes. However, sharing lanes with vehicles and other users tends to cause safety issues for riding E-Scooters. Conventional methods are often not applicable for analyzing such safety issues because well-archived historical crash records are not commonly available for emerging E-Scooters.

Perceiving the growth of such a micro-mobility …

Design, Synthesis And Characterization Of Carbohydrate Based Macrocycles, Photo Responsive Derivatives, And Glycoconjugates Based Low Molecular Weight Gelators, Surya Bahadur Adhikari

Chemistry & Biochemistry Theses & Dissertations

Functional glycoconjugates are important classes of compounds with many applications in different research fields. Our lab has been studying the synthesis and applications of different classes of glycoconjugates ranging from macrocycles to sugar heterocycle derivatives. Due to the importance of these compounds, our research is based on development of synthetic methods for various carbohydrate derivatives. This dissertation includes introduction and overview of projects, followed by the synthesis and studies of several different series of glycomacrolactones. The second project focuses on two classes of photoresponsive molecules, the coumarins and diarylethenes. The third project involves the synthesis and self-assembling properties of isoxazole-based …

Phytoplankton Community Response To Upwelling Events: Distribution And Abundance Investigated Using Genomic Methods, Sveinn V. Einarsson

OES Theses and Dissertations

Upwelling events are known to support blooms of phytoplankton, important primary producers at the base of the oceanic food web. Phytoplankton community structure changes in response to upwelling support higher trophic level growth and increased efficiency of carbon export from the euphotic zone. While these events occur globally, this study examined upwelling in coastal regions, where alongshore winds can drive Ekman transport and upwelling of deeper waters. The two upwelling regimes examined were the California Current System and the Alaskan Beaufort Sea. In the California Current System, the relative diatom community composition was examined using 18S sequencing to determine how …

A Copula Model Approach To Identify The Differential Gene Expression, Prasansha Liyanaarachchi

Mathematics & Statistics Theses & Dissertations

Deoxyribonucleic acid, more commonly known as DNA, is a complex double helix-shaped molecule present in all living organisms and hosts thousands of genes. However, only a few genes exhibit differential expression and play a vital role in a particular disease such as breast cancer. Microarray technology is one of the modern technologies developed to study these gene expressions. There are two major microarray technologies available for expression analysis: Spotted cDNA array and oligonucleotide array. The focus of our research is the statistical analysis of data that arises from the spotted cDNA microarray. Numerous models have been proposed in the literature …

Synthesis And Characterization Of 4,6-Protected Glucosamine Derivatives And Branched Glycoconjugates, Jonathan Bietsch

Chemistry & Biochemistry Theses & Dissertations

Low molecular weight gelators (LMWGs) are small molecules that self-assemble in appropriate solvents to form three dimensional networks that immobilize the solvent, creating a supramolecular gel. The self-assembly of LMWGs occurs through non-covalent interactions such as hydrogen bonding, aromatic interactions, donor-acceptor interactions, Van der Waals interactions, hydrophobic forces, halogen bonding, etc. Due to self-assembly occurring through reversible non-covalent interactions, supramolecular gels can undergo a gel to solution transformation. Because of this, these materials can be sensitive to external stimuli such as temperature changes, pH changes, and other stimuli that effect non-covalent interactions. This makes the synthesis of LMWG’s an appealing …