Digital Commons Network^™

Uranium(Vi) & Thorium(Iv) Speciation In Organic Media Containing Organophosphorus & Diglycolamide Extractants, Joel Castillo

UNLV Theses, Dissertations, Professional Papers, and Capstones

Developing sustainable green energy systems is a continually growing concern as the world is faced with urgent issues of climate change and global warming. Nuclear energy provides one of the most efficient solutions to supplying power to the electrical grid without causing more carbon pollution. There are nearly a hundred thousand metric tons of used nuclear fuel (UNF) stored on-site at decommissioned nuclear power plants for an indefinite period of time. Achieving a finalized closed fuel cycle is a crucial part in developing the nuclear energy necessary for combating the issues of pollution and greener energy. Understanding actinide speciation especially …

Mechanically Cost-Effective Approach For Bipedal Walking In Robots Using Instantaneous Collision Angle, Smit R. Patel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Humans, as bipedal locomotors, are effective at reducing the mechanical cost of transport (CoTmech) by adopting movement strategies and gaits that minimize energy expenditure for a given distance. By using different gaits at different speeds, leveraging their long spring-like tendons and muscle elasticity which store and release energy during movement, humans reduce the mechanical effort required for locomotion. Current locomotion solutions offered in bipedal robots, based on legacy walking and running gait models, are not great at energy efficiency unless walking at very low speeds. Additionally, the control system of robots, designed to ensure stability and adaptability, requires substantial resources, …

Reproducible Research Data Pipelines – Case Study Of Bubble Collapse In Subcooled Nucleate Pool Boiling, Blake Naccarato

UNLV Theses, Dissertations, Professional Papers, and Capstones

Vapor bubble collapse is relevant to the study of subcooled nucleate boiling, as can occur in power plants and missile systems, in studies of wear due to cavitation, and even in the study of hydrothermal vents in the Earth sciences. Empirical correlations relate the rate of bubble collapse to thermal conditions of the subcooled fluid, and one may choose to produce a purpose built correlation for any process. However, they are time and resource intensive due to the data and process requirements for automated bubble tracking. A reproducible research data pipeline has been developed to discriminate between existing correlations for …

Nuclear Fuel Cycle Chemistry: A Density Functional Study, Eduardo Montoya

UNLV Theses, Dissertations, Professional Papers, and Capstones

The nuclear fuel cycle aptly describes the life cycle of nuclear fuel sources such as uranium. From its early forms in naturally bearing ores, to its high-temperature sintering into a fuel pellet, the chemistry uranium experiences throughout the fuel cycle is diverse, driving many experimental efforts towards understanding its chemistry to both improve nuclear technologies and advance the safety and handling of nuclear materials. Computing techniques and methodologies can be used to supplement experimental research and are readily available to researchers interested in utilizing computing-based data to support experimental findings. Density functional theory (DFT) is commonly practiced, reliably predicting the …

Delineating Genetic Influences On Neurodegenerative Disorders And Infectious Diseases Through Advanced Computational Methods, Xiaowei Zhuang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Genetics plays a critical role in understanding the molecular mechanisms underlying neurodegenerative disorders and pathogen evolution in infectious diseases. For example, identifying genetic variants associated with a disease phenotype uncovers functional pathways that could lead to potential drug targets and therapeutic interventions. In addition, tracking the genetic evolution of pathogens enables early detection and warning of infectious disease outbreaks. In both applications, given the large amount of genetic data, advanced computational methods, including longitudinal and multivariate models, could significantly boost the statistical power and capture interrelationships among traits, environmental factors and genetic influences. This dissertation focuses on four applications of …

The Effects Of First Responder Stress & Trauma On Spouses And Romantic Partners, Eden Thiess

UNLV Theses, Dissertations, Professional Papers, and Capstones

First responder jobs pose unique difficulties due to the sheer number of traumatic events that they witness and personally experience. Research has demonstrated some effects of stress and trauma on family relationships, but the literature lacks an understanding of the ways that first responder trauma and stress affects their marriages and romantic relationships. The current study’s purpose was to investigate the experiences of first responder spouses and partners within the Las Vegas area in regards to stress, trauma, and relationship dynamics as influenced by the first responder role. In this study, 11 participants who were in a marriage or romantic …

Prediction Of Cost And Schedule Changes In Transportation Projects Through Historical Bid And Change Order Document Analysis – Using Oklahoma Dot Project Cases., Rabin Shrestha

UNLV Theses, Dissertations, Professional Papers, and Capstones

Construction bid documents encompass project specifications, drawings, schedules, and other critical details and are the foundation for project bidding and execution. Accurate bid documents are essential to ensure project bids are competitive, realistic, and aligned with requirements. However, bid documents are susceptible to risks from various sources. Failure to identify and rectify these risks can result in inaccurate cost estimates and higher bids. Therefore, identifying and resolving risks within bidding or contract documents are of utmost importance. While prior research has shed light on potential risk factors within the bid documents, a noticeable gap remains in the literature regarding identifying …

Addressing Low Molecular Weight Chemical Peaking Events During Direct Potable Reuse By Granular And Biological Activated Carbon, Ceonie Washington

UNLV Theses, Dissertations, Professional Papers, and Capstones

Direct Potable Reuse (DPR) is an innovative solution designed to address water scarcity by treating wastewater to directly produce safe drinking water. As droughts and water shortages become more frequent, DPR offers a sustainable and localized water supply by incorporating advanced treatment processes. DPR systems typically rely on a combination of technologies such as ozone followed by biological activated carbon (O3/BAC), reverse osmosis (RO), and advanced oxidation processes (AOPs) to remove a wide range of contaminants. However, low molecular weight organic compounds (LMWCs), particularly volatile organic compounds, can sometimes pass through RO membranes and AOP systems.

California's DPR regulations currently …

Analyzing Sars-Cov-2 Wastewater Surveillance Data For Public Health Impact In Southern Nevada, Casey A. Barber

UNLV Theses, Dissertations, Professional Papers, and Capstones

Background: Early in the COVID-19 pandemic, researchers determined that levels of severe acute respiratory coronavirus 2 (SARS-CoV-2) genetic material in wastewater could provide information about COVID-19 occurrence in communities. Wastewater-based epidemiology (WBE) efforts have subsequently expanded throughout the U.S. and internationally; the U.S. Centers for Disease Control and Prevention (CDC) initiated its National Wastewater Surveillance System (NWSS) in September of 2020 and continues its SARS-CoV-2 wastewater monitoring efforts following the end of the federal COVID-19 public health emergency in May 2023. The field of WBE has reached a critical juncture in determining the future of how SARS-CoV-2 wastewater surveillance data …

Understanding Failure Mechanisms For Two Colorectal Anastomosis Techniques, Youssef Sherif Sadek Fahmy

UNLV Theses, Dissertations, Professional Papers, and Capstones

Colorectal Surgery continues to be one of the most common gastrointestinal surgeries performed in the US. A common complication known as Anastomotic Leakage (AL) that threatens up to 30% of patients with this surgery. Many cases of AL can decrease the quality of life for patients or extensively extend hospital stays, and in many cases, lead to death. Researchers have studied this complication in clinical trials, yet few studied the mechanics of stapled anastomosis in controlled environments. The purpose of this research was to understand the mechanical interaction between the staples and the tissue, and to eventually apply it in …

Development Of Uranium Fluoride Microstructures, Harry Jang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Uranium microstructured materials with controlled size and shape have found applications in several branches of the nuclear industry including as targets for medical isotopes production, fuels for nuclear reactors, standards for analytical measurements, and energy sources for space exploration. Morphological studies of actinide materials are also highly relevant to nuclear forensics-related work. Other potential applications include information storage, catalysis, sensors, and luminescent devices. Most studies on uranium microstructured materials have focused on binary oxides, nitrides, carbides, and fluorides, with the spherical shape being the dominant morphology. Prior to the work reported in this dissertation, aside from UF4 microspheres (ms) and …

The Relationship Between Police Stress And Officer Misconduct, Leobardo Lopez-Cristobal

UNLV Theses, Dissertations, Professional Papers, and Capstones

Recent high-profile and controversial police-related incidents have sparked an intensified public discourse on police misconduct. This has resulted in increasing calls for greater accountability and transparency within U.S. police agencies. Much of the existing research on police misconduct centers around two competing explanations: the "bad apples" perspective, which attributes misconduct to individual officers, and the "bad barrels" perspective, which points to systemic or organizational factors (Rojek, Decker, & Wagner, 2015). However, one factor that has been underexplored in the literature is the role of police stress in influencing deviant police behavior. Previous studies suggest a potential link between police-related stress …

Implicit Bias: Principal Leadership And Social Justice, Tamra Lynn Brooks

UNLV Theses, Dissertations, Professional Papers, and Capstones

Benson & Ellison (2017) contend that among the first steps toward addressing a more diverse school and student body is an augmentation of cultural competency leadership, which begins with principals knowing how to address their own implicit biases as leaders in their schools. The purpose of this qualitative research study was to explore different ways principals address implicit biases within their schools and what is needed to help them address implicit bias with teachers and staff. The study addressed two research questions: “What do school principals perceive as biases among teachers and staff?” and “What do principals perceive is needed …

How Culture Impacts Mental Health Help-Seeking Behaviors In College-Aged Chinese Americans, Hui Ching Chan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Adolescents are the most vulnerable to mental health issues in the United States, however, they are the least likely to receive relevant professional services. Particularly, young Chinese American adults who are influenced by traditional Chinese culture retain a higher reluctance to mental health-related help-seeking behaviors.

Chinese American culture is co-constructed with families through parents’ worldviews, parenting styles, socio-economic statuses, and English proficiency. Several studies also suggest that mothers and fathers in Chinese American families play distinct roles in shaping youngsters’ perceptions of mental health awareness. As a result, the culture perceived from families has a significant impact on young Chinese …

Α-Quartz Plastic Strength Investigation Via Diffraction Experiments On Novaculite Using A D-Dia And Elastic Plastic Self-Consistent Interpretation, Denali Jivanjee Medina

UNLV Theses, Dissertations, Professional Papers, and Capstones

The plastic response of experimentally deformed quartz provides insight into the strength of ductile shear zones that has implications for tectonic, lithospheric, and ore deposit models. We present a suite of 15 uniaxial deformation experiments on Arkansas novaculite conducted in a DDIA apparatus with in-situ synchrotron x-rays. Experimental temperatures range from 25 C to 1334 C with pressures between 1.39 GPa and 3.1 GPa, and strain rates between 1x10-5 s-1 and 9x10-6 s-1. Macroscopic sample strain ranges from 3% to 24%. d-spacings from the (101), (110), (200), (201), and (112) lattice planes were measured, producing lattice strain up to ~5%. …

Investigation Ionic Polymer Metal Composite Capacitors Through Fabrication, Experimentation, And Modeling, Liya S. Napollion

UNLV Theses, Dissertations, Professional Papers, and Capstones

The increasing demand for greater energy storage capacity alongside the need to minimize the size of various devices, such as hybrid electric vehicles, medical devices, and pulsed power systems—has highlighted the necessity for advanced polymer film capacitors with high energy density. While traditional batteries and electronic devices have generally sufficed for many applications, their inherent size limitations hinder their ability to deliver the high levels of peak power required for certain demanding applications. This shortfall highlights the critical ongoing challenge within the energy storage sector to improve technology and more effectively meet these growing power requirements. Flexible Ionic Polymer Metal …

Control Of X-Delta Arm And Self-Leveling Robot Systems For Uav Applications, Prathibha Sobha

UNLV Theses, Dissertations, Professional Papers, and Capstones

The water droplet penetration test (WDPT) is an environmental assessment method for analyzing soil properties by measuring the penetration of water droplets into soil. This test provides insights into soil moisture retention and resilience, especially valuable in fire-prone or arid regions where soil recovery and erosion control are essential. Although this project does not conduct an actual WDPT, it investigates two key robotic systems designed to support such applications: an X-delta robot arm, which simulates precise droplet delivery patterns, and a self-leveling platform that ensures stability on uneven terrain, where the X-delta robot is mounted. Together, these systems examine the …

Fast Neutron & Gamma-Ray Scintillation And Broadband Photoluminescence From Gallium Nitride & Gallium Oxide: Developing Radiation-Hard Diagnostic Platforms, Daniel Jesus Valdes

UNLV Theses, Dissertations, Professional Papers, and Capstones

Integrated scintillation and electronics processing materials are of critical importance in environments exposed to high levels of radiation, such as nuclear fusion diagnostics and space missions. This dissertation focuses on the radiation detection capabilities of gallium oxide (Ga2O3) and gallium nitride (GaN), exploring their responses to fast neutrons and gamma rays. Using high-energy neutron beam facilities at Los Alamos Neutron Science Center (LANSCE) Flight Path 4FP60R, we exposed both Ga2O3 and GaN crystals to neutron irradiation spanning an energy spectrum ranging from 1 to 400 MeV. A Pi-Max 4 fast-gated Intensified CCD (ICCD) camera captured the transient scintillation responses for …

From Resistance To Host Response: An Integrative Study Of C. Difficile Infections, Amber Consul

UNLV Theses, Dissertations, Professional Papers, and Capstones

Clostridioides difficile infection (CDI) is a major healthcare challenge, causing severe gastrointestinal illness and significant mortality. Understanding the mechanisms of antibiotic resistance, epidemiology, and immune response in CDI is critical for developing effective treatments and prevention strategies.

This dissertation encompasses three complementary studies. The first study investigates the genetic mechanisms underlying cephalosporin resistance in C. difficile strain 630 through differential gene expression analysis. The second study provides a descriptive epidemiological analysis of C. difficile ribotypes in a Las Vegas patient population, highlighting differences between healthcare-associated (HA-CDI) and community-associated (CA-CDI) cases. The third study integrates serum analyte profiling and transcriptomic analysis …

The Effects Of A Healthcare Simulation Escape Room On Clinical Judgment: A Randomized Controlled Trial, Jennifer Peltier

UNLV Theses, Dissertations, Professional Papers, and Capstones

Background: The predominant pedagogy of traditional lecture-based learning should include meaningful active content to foster clinical judgment, engagement, and knowledge retention. Innovative active learning strategies must be tested to understand if they can better facilitate nursing learners’ readiness for practice.

Aims: This research study investigated the impact of a healthcare simulation escape room as an innovative platform on individual and team clinical judgment to determine whether this active learning strategy can benefit nursing learners’ preparedness and increase clinical judgment.

Method: A randomized, double-blinded, waitlist control design was used to examine the effect of a healthcare simulation escape room on clinical …

Addressing Inference Time Of Machine Learning Models In Embedded Systems, Samuel Black

UNLV Theses, Dissertations, Professional Papers, and Capstones

Embedded Systems are used for a wide range of specialized computing purposes including surveyal, safety, security, and quality of life. Many areas that embedded systems are used in require the use of machine learning models. Constraints can be placed on embedded systems. Timeliness of execution, user satisfaction, security, power, and resource limitations must be considered when designing for embedded systems. Neural networks excel at complex tasks that are otherwise intractable, but their relatively high computational cost poses a challenge for inclusion in embedded systems. Neural network architectures should be optimized to reduce the total number of operations performed while maintaining …

A Performance Guide To Lisabeth-Claude Jacquet De La Guerre’S Cantate Fran Oise: Semel, Cho Hee Hwang

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study explores one of the French cantatas, Semel , composed by lisabeth-Claude Jacquet de La Guerre (1665–1729) to provide an analysis of her sophisticated text painting and a performance guide for singers. The cantata genre originated in Italy and by the early-eighteenth century, it flourished in France as well: approximately eight hundred French cantatas were composed between 1700 and 1730. lisabeth-Claude Jacquet de La Guerre was among the French composers who adopted the genre, along with Jean-Baptiste Morin (1677–1745), Nicholas Bernier (1664–1734), Fran ois Couperin (1668–1733), and Louis-Nicolas Cl rambault (1676–1749). In 1715, Jacquet de La Guerre published the …

Non-Contact Acoustic Emission Detection Of Rail Defects Using Air-Coupled Sensors, Lei Jia

UNLV Theses, Dissertations, Professional Papers, and Capstones

Rail defects, whether internal or external, present significant safety risks. Acoustic Emission (AE) technology has emerged as a promising technique for monitoring damage progression and detecting these rail defects. This project addresses this critical concern by testing air-coupled optical microphones for non-contact AE detection. The goal of this research is to investigate AE signal characteristics using both rail-mounted and vehicle-mounted methods, establishing the understanding of AE signals in relation to defects and their effectiveness in identifying them.

This research focused on investigating air-conduct sensors in the lab-controlled pencil lead break (PLB) test. The objective was to evaluate the propagation characteristics …

The Impact Of Father-Daughter Relationships On Dating And Relationship Behaviors For African American Women: A Qualitative Analysis, Neeah A. Lofton

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study examines how African American father-daughter relationships can impact their dating and relationship behaviors. This highlights an important role African American fathers play in shaping their daughter’s development and expectations within romantic relationships. The purpose of this qualitative (grounded theory) study was created to unravel the unique dynamics that shapes African American women's views on intimacy, self worth and relationships expectations. The research seeks to fill existing gaps in literature, moving beyond the notion of African American father presence to explore the emotional context that influences their daughter’s romantic lives. The research question for this study is for African …

Charging During The Stay: The Effects Of Ev Chargers’ Availability And Pricing On Consumer Perceived Utilitarian Value And Behavioral Intentions, Wenjia Han, Cass Shum, Guoguang Wan

Hospitality Faculty Research

Hotels are increasingly hosting EV chargers. Yet, scant research examines the effects of EV chargers on consumer behavioral intentions toward the hotel. This study draws on the expectancy theory and examines the effect of EV chargers availability and the availability of surrounding chargers on consumer hotel booking intentions and willingness to pay a price premium. The results of two scenario-based experiments showed that free or paid EV chargers enhance consumers’ perceived utilitarian value and behavioral intentions. The effects are partially amplified when the availability of surrounding chargers is limited. This research contributes to the literature on hotel add-on services and …

What Works When Working Together?: Cross-Sector Collaboration Barriers & Facilitators Of A Built Environment Health Impact Assessment In Southern Nevada, Maxim Gakh, Courtney Coughenour, Bertille Assoumou, Emily C. Strickler, Timothy J. Bungum, Jennifer R. Pharr, Pashtana Usufzy, Megan Mcdonough, Nicole Williams Bungum, Mindy Meacham

Environmental & Global Health Faculty Research

Purpose: Cross-sector collaboration can improve community health because decisions made across sectors influence health. Health Impact Assessments (HIAs) and other health-focused, cross-sector collaborations encounter challenges. This case study uses a completed HIA to explore factors impeding and supporting health-related cross-sectoral collaboration.

Methods: Semi-structured key informant interviews with 10 of 12 HIA working group participants were conducted and analysed using a content analysis approach.

Results: Analysis generated 48 codes across seven themes in three primary groups: HIA as a collaborative tool; logistical and systemic barriers; and benefits and logistical, interpersonal, and sectoral facilitators. Recognizing the importance of knowledge, analysis, and …

Invertebrate Functional Diversity Of Fossils From Arrow Canyon, Nevada, Nathaniel Valentine

Undergraduate Research Symposium Podium Presentations

Paleontology can be used to study how ecosystems evolve and respond to changes in the environment. Here we examine invertebrate fossils from the Pennsylvanian, a time period that ranged from 323.2 to 298.9 million years ago, which are preserved along the walls of Arrow Canyon (Nevada) in the Bird Spring Formation. We surveyed three sites within the canyon, and used data from the Paleobiology Database to create a list of taxa found on the canyon from this time interval. Although ecosystems have traditionally been studied using the composition of the ecosystem (the number of species), recent work has shown that …

Potential Cell Preservation In Mars-Relevant Clay Minerals, Hanford Gerille Gonzales, Leena M. Cycil, Elisabeth Hausrath

Undergraduate Research Symposium Posters

This study investigates the potential of Fe-nontronite, a clay mineral found on Mars, to preserve biological cells and retain biosignatures such as trace metals. The research explores the preservation potential of nontronite by reacting it with cells under the following conditions: 1) reacting cells with nontronite precursors at low temperature and 2) reacting cells with the already synthesized nontronite made at high temperature. Microbial species Shewanella oneidensis and Geobacter metallireducens, known for their relevance to iron-rich environments, were introduced in intact and lysed forms to assess their interactions with each condition of nontronite. Preliminary results from scanning electron microscopy (SEM) …

The Motherhood Wage Penalty: Estimation Across Various Factors, Mario Velazquez

Undergraduate Research Symposium Posters

Maternity and family leave policies are implemented in the workplace and sometimes even mandated by governments to allow first-time mothers to provide care for their newborns and recover from childbirth. However, these policies vary by country, and previous research publications have found that women face a “motherhood penalty” when they take a leave from work, leading to reduced earnings compared to women who do not have children. The main purpose of this paper is to validate whether new mothers do in fact face a decrease in their earnings over time, to compare this penalty across numerous variables, and to explore …

Parental Failure And The Double Standards Of Screen Time Discourse On Popular Parenting Blogs, Christian Casarez, Annaliese Grant

Undergraduate Research Symposium Posters

Understanding screen time discourse is vital in grasping people’s relationship with media comprehensively. This research seeks to add to this body of knowledge by highlighting the double standards present within parenting blogs’ narratives on screen time. Utilizing a qualitative analysis conducted on a dataset of over 200 coded articles (n=220) from parenting blog giants such as Parents.com and SheKnows.com, I argue that popular parenting blogs simultaneously platform content that pushes parents to constantly manage and mitigate their children’s screen time use, while at the same time implicitly encouraging parents to utilize apps, audio, content, and devices to do so. In …