Digital Commons Network^™

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 …

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 …

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, …

Real-Time Predictive Analytics For Healthcare Monitoring And Terrain Classification Using Data Streaming And Online Learning, Ayemon Baraka

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis develops a scalable, real-time predictive framework aimed at improving outcomes in healthcare monitoring and gait classification. Specifically, it addresses two primary applications: early detection of cardiovascular events, myocardial infarction (MI) and arrhythmia, through continuous analysis of ECG data streams; and adaptive terrain classification from gait data. Utilizing data streaming technologies such as Apache Kafka and Apache Spark, coupled with machine learning models, this framework enables near real-time and precise predictions from high-throughput, real-time data. Furthermore, the integration of online learning frameworks, including the River API and TensorFlow I/O, allows for continuous model adaptation, enhancing the system’s responsiveness and …

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 …

Biological Reduction Of Mixed Oxyanions In Wastewater Brine, Katherine J. Earp

UNLV Theses, Dissertations, Professional Papers, and Capstones

Treatment of contaminated brine water is an area of active research spurred by the use of advanced treatment technologies, such as membrane separation, reverse osmosis, ion exchange, etc. for water reuse and recycling, which has become critical due to the impact of climate change on water resources throughout the globe. Biological reduction of harmful organic and inorganic pollutants in water has been demonstrated as an effective method for water and wastewater treatment and would be a potential technology for brine treatment. However, biodegradation of contaminants in high salinity waters is challenging because most microbial communities cannot survive brine environments. The …

Effect Of Epistemic Cognition And Self-Regulation On The Evaluation Of Online Information, Devin T. Foschi

UNLV Theses, Dissertations, Professional Papers, and Capstones

While research has shown that epistemic cognition plays an important role in self-regulation, the way in which it does so in online contexts needs further research. The objective of this dissertation was to examine the relationship between Internet-specific epistemic cognition and Internet-specific self-regulated learning, and to use a mixed-methods approach in order to expand upon the way learners undergo the evaluation of information in online spaces beyond the traditional method of only using self-report measures and other common quantitative techniques. Using an explanatory sequential mixed-methods design, Phase 1 (N = 117) used quantitative methods to first look at the relationship …

The Assignment Despite Objection Construct: Its Efficacy And Utility In Measuring Nurse-Perceived Unsafe Staffing Events And Associated Outcomes, Debra F. Fox

UNLV Theses, Dissertations, Professional Papers, and Capstones

Purpose: This three-manuscript approach provided a progressively built overview of Assignment Despite Objection as a construct used by nurses to document their perceptions of unsafe staffing events and as an unstudied concept in the staffing outcomes literature.

Background: All nurses have an ethical, legal, and professional responsibility to refuse or object to assignments they believe are unsafe for their well-being or their patient’s safety. Assignment Despite Objection being the only widely used construct nurses use to document these perceptual details. No studies have focused on Assignment Despite Objection as a construct or concept, leaving a complete gap in understanding its …

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 …

Uptake Of Contaminants Of Emerging Concerns (Cecs) By Plants Irrigated With Recycled Waters, Abid Hussain

UNLV Theses, Dissertations, Professional Papers, and Capstones

The increasing demand for water in arid and semi-arid regions necessitates the use of recycled water (RW) for irrigation. RW is a viable alternative to conventional irrigation water at most locations, but it can be a major route for contaminants of emerging concerns (CECs) to be taken up by the tissues of food crops, thereby leading to their subsequent entry into the food chain. CECs include pharmaceuticals, personal care products, and industrial chemicals that are generally present at low concentrations in environmental waters, hence their common designation as trace organic compounds (TOrCs), and CECs also include microbiological constituents such as …

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 …

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 …

Developing A Remote Gamma Spectra Collection System For Radiation Sciences At The University Of Nevada, Las Vegas, Haven Searcy

UNLV Theses, Dissertations, Professional Papers, and Capstones

Educational institutions of all levels have been significantly impacted by the COVID-19 epidemic with none more so than higher education. The challenges faced by researchers are numerous while performing a study and have only increased since the pandemic. Many colleges or universities have halted research to cut off unnecessary contact in order to protect study participants and research personnel. In the Department of Health Physics and Diagnostic Sciences (DHPDS) at the University of Nevada Las Vegas, a solution was developed that would allow scientists and students alike to be able to analyze already prepared samples either in the lab or …

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 …

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 …

Removal Capabilities Of Zeolite And Zero Valent Iron With High-Level Waste Tank Radionuclides And Metals: Cesium, Strontium And Chromium, Colette R. Towles

UNLV Theses, Dissertations, Professional Papers, and Capstones

High level nuclear waste (HLW) has been disposed for temporary storage in underground steel tanks at the Department of Energy Nuclear sites. For example, at the Hanford Site, WA, and Savannah River Site (SRS), SC, HLW account for eighty-eight million gallons (Mgal) and 450 million Curies (MCi) of radioactivity. In the early nuclear activity at Hanford, the waste was discharged to single-shell steel tanks, and the lack of secondary containment allowed leaks, contaminating soil and groundwater. Despite tremendous efforts to stabilize the liquid waste at nuclear sites, treatment is complex, costly, and time-consuming; therefore, HLW may have to be stored …

Density-Driven Investigations Of Ruthenium Binary Compounds Rux2 (X = O, S, N), Melanie White

UNLV Theses, Dissertations, Professional Papers, and Capstones

Exploration and fine-tuning of the energy landscape of materials can be accessed by means of changes in material density, a key principle of high pressure research. Density-driven changes impact variations in oxidation states and coordination numbers for the element constituents of a compound. Pressure-induced modification of intrinsic density can promote the formation of new materials, variations in physical properties, and transformations in crystallographic symmetry. With this as our foundation, we focus on ruthenium binary compounds - altering the anion species to change electronegativity while probing pressure and temperature effects. This led us to the present study of ruthenium oxide RuO2, …

Tracking Joint Movement Using Optical Flow, Isabella Paperno

UNLV Theses, Dissertations, Professional Papers, and Capstones

We developed an algorithm that aims to move us closer to detecting early signs of arthritis. The program processes and analyzes X-ray videos using coyote and dog cadavers as models to examine the range of motion around the hip and connecting joints using optical flow techniques that track motion and velocity. We focus on how optical flow techniques track embedded metal markers and verify accuracy through comparisons with XMALab (X-ray motion analysis lab). Once proven as an accurate alternative, the focus will switch to markerless tracking and become a proof-of-concept for optical flow to be used in place of XMALab, …

Integrating Deep Traffic Prediction And Environmental Impact Assessment Using Noisy Real-World Data In Las Vegas, Tarek Bin Zahid

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis introduces an integrated framework for advanced traffic prediction and real-time emission estimation, designed to aid urban planning and environmental monitoring. Utilizing a graph-based transformer model, it predicts traffic conditions across the Las Vegas road network, drawing on spatial and temporal data from a large-scale sensor network. The study significantly expands the dataset from 26 to approximately 900 sensors, enhancing predictive accuracy and regional coverage. Inspired by masking techniques and strategies tailored to incomplete datasets, the model effectively handles real-world, noisy data without relying on resource-intensive imputation. Innovative training approaches enable robust traffic flow predictions despite missing or imperfect …

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 …

Precision And Efficacy Of Rna-Guided Dna Integration In High-Expressing Muscle Loci, Made Harumi Padmaswari, Gabrielle Bulliard, Shilpi Agrawal, Mary S. Jia, Sabin Khadgi, Kevin A. Murach, Christopher E. Nelson

Biomedical Engineering Faculty Publications and Presentations

Gene replacement therapies primarily rely on adeno-associated virus (AAV) vectors for transgene expression. However, episomal expression can decline over time due to vector loss or epigenetic silencing. CRISPR-based integration methods offer promise for long-term transgene insertion. While the development of transgene integration methods has made substantial progress, identifying optimal insertion loci remains challenging. Skeletal muscle is a promising tissue for gene replacement owing to low invasiveness of intramuscular injections, relative proportion of body mass, the multinucleated nature of muscle, and the potential for reduced adverse effects. Leveraging endogenous promoters in skeletal muscle, we evaluated two highly expressing loci using homology-independent …

Project Tracking With Mobile Devices, Mike Son

Electronic Theses, Projects, and Dissertations

This innovative project tracking with mobile devices provides comprehensive access to project information, modernized communication, and effective work management from any device. Through a simple interface, it enables real-time collaboration, work delegation, and progress monitoring, making project management simpler everywhere. A standout feature of this application is its provision of a dedicated API (Web Programming Interface) for mobile devices, enabling seamless integration and synchronization between the web application and mobile platform apps. This guarantees a consistent and integrated user experience across all devices, allowing for quick task updates, and information sharing. The web application emphasizes security, with secure encryption and …

Comparative Assessment Of Machine Learning And Deep Learning Models For Drug Effectiveness Using Sentiment Analysis, Blessing Ogechukwu Nwogu

Electronic Theses, Projects, and Dissertations

In recent years, the proliferation of online patient-generated drug reviews has created a valuable resource for assessing drug effectiveness and patient satisfaction, with sentiment analysis emerging as a powerful tool for extracting insights from this unstructured data.

This culminating research project conducted a comparative analysis of traditional Machine Learning (ML) and Deep Learning (DL) models for assessing drug effectiveness using sentiment analysis of participant reviews. The research aimed to evaluate the performance of Support Vector Machine (SVM), XGBoost, Random Forest, Long Short-Term Memory (LSTM), and Bidirectional Encoder Representations from Transformers (BERT) models in this context. This culminating research project addressed …

Container Runtime Vulnerability Mitigation Using User Namespace Isolation, Alexander Edsell

Electronic Theses, Projects, and Dissertations

Although containers have revolutionized application deployment by allowing for rapid and consistent deployment, their growing adoption has also raised significant security concerns. Each container is an isolated instance of an operating system that comes pre-packaged with the users desired applications. With multiple containers running on a host machine, an adversary can potentially break out of the container into the host machine. This project investigates the effectiveness of user namespace isolation as a security mechanism to mitigate container escape vulnerabilities that target the container’s runtime.

The research questions are: Question 1, does user namespace isolation mitigate container runtime vulnerabilities that target …

The Significance Of Continuous User Authentication On Mobile Devices, Mikayla Lawrence

Electronic Theses, Projects, and Dissertations

With the constant evolution of technology specifically on mobile devices, keeping personal and sensitive information safe has become increasingly vital. Continuous user authentication marks a major step forward in mobile security because it provides ongoing verification of user identity beyond the initial log in. This research explores the significance of continuous user authentication systems across mobile devices through literature-based analysis. The following research questions are addressed: (Q1) How effective are continuous user authentication methods in mitigating mobile device threats? (Q2) What are the vulnerabilities associated with continuous user authentication systems on mobile devices? (Q3) How do different continuous user authentication …

Artificial Intelligence And Cracks In The Foundation Of Intellectual Property, Robin C. Feldman

Faculty Scholarship

Our implicit image of progress and the standards we use to calibrate human contribution to progress are quietly at risk from the onslaught of artificial intelligence (AI). AI has the potential to significantly shrink the pool of creative work that is protectable by intellectual property (IP) law and the range of information that is protectable, as well as shrinking the value proposition of IP regimes themselves.

As society faces this changing landscape, we must tread carefully to distinguish fears about AI from the task of defining the boundaries of intellectual property, whose theoretic concepts aren’t designed to bear such weighty …

(R2104) On The Qualitative Results Of Riemann-Liouville Fractional Order Nonlinear Neutral Singular Systems With Mixed Delays, Abdullah Yiğit, Cemil Tunç

Applications and Applied Mathematics: An International Journal (AAM)

In this manuscript, we discuss new conditions for asymptotic stability of nonlinear Riemann- Liouville fractional mixed-delay neutral singular systems. By constructing a set of improved Lyapunov-Krasovski˘ı functionals (LKFs), we establish some new delay-dependent conditions in terms of matrix inequality, which guarantees that the systems are asymptotically stable. In the particular case, we give four numerical examples with their solutions and graphs via MATLAB software demonstrating the practical applicability of these proven conditions. With this study, some conditions existing in the literature are developed and generalized.

(R2113) A Numerical Method For Solving Linear First-Order Volterra Integro-Differential Equations With Integral Boundary Condition, Zelal Temel, Musa Cakir

Applications and Applied Mathematics: An International Journal (AAM)

We investigate an efficient numerical method for the linear first-order Volterra integro-differential equations with integral boundary condition. To solve this problem, boundaries are determined for its derivative and the solution. The numerical solutions of the problem are modeled over a uniform mesh using the composite right-side rectangle concept for the integral component and the implicit difference rules for the differential component. Next, the stability and convergence of the numerical approach are discussed. The numerical experiments are presented confirming the accuracy of the proposed scheme.

Alfred Russel Wallace Notes 33. The Story In Evolution., Charles H. Smith

Faculty/Staff Personal Papers

Alfred Russel Wallace (1823-1913) is best known for his independent formulation of the principle of natural selection. In this work I first review my understanding of Wallace’s intellectual development on this subject, including the notion that he had no model for the evolution of higher consciousness as of his first treatment of natural selection in 1858. This leads to some conclusions about his approach to the subject, and links to parallel ideas inherent in the philosophy of Baruch de Spinoza (1632-1677).