Digital Commons Network^™

Mechanisms For The Incorporation And Distribution Of Radionuclides In Near-Surface Fallout, Marc Alan Fitzgerald

UNLV Theses, Dissertations, Professional Papers, and Capstones

Fallout is the radioactive glass formed from a mixture of vaporized anthropogenic materials with proximate environmental material. These glassy byproducts constitute a compositional record of environmental materials such as soil and vapor precursors that are responsible for chemical heterogeneity in the glasses. The work of this dissertation is to untangle these different sources of compositional heterogeneity, distinguishing low-abundance vaporized anthropogenic-rich material from natural compositions, in order examine soil behavior and chemical evolution during fallout formation. Unfortunately, mixing convolutes the multivariate elemental relationships in these melts due to overlapping element abundances that might distinguish different source materials and chemical behaviors, making …

Employee Perceptions Of Organizational Corporate Responsibility And Their Effect On Employee Organizational Commitment, Lisa R. Davis

UNLV Theses, Dissertations, Professional Papers, and Capstones

The debate over whether organizations play a part in society beyond economic profit has been a major focus of research in corporate social responsibility (CSR). These debates have been mainly looked at from the macro (societal) or the meso (institutional) level. Very little research has been done on the role of the firm and looking at CSR from the micro (individual) level. Questions regarding the role of work for employees, securing economic benefits or making a difference in the world, would vary greatly depending on the individual and the importance they place on these areas in their own lives. Scholars …

Design And Preliminary Evaluation Of A Supercritical Carbon Dioxide Brayton Cycle For Solar Dish Concentrator Clean Energy Production, Danielle Nobles-Lookingbill

UNLV Theses, Dissertations, Professional Papers, and Capstones

As we move toward energy independence and more ambitious clean energy goals, solar energy research must push the efficiency limits of traditional energy generation systems. Increases in efficiency can be achieved by increasing the hot temperature of the power cycle. Recent research demonstrates the potential for increased efficiency and a vastly smaller component size when supercritical carbon dioxide Brayton power cycles are used. Concentrated solar and nuclear heat sources are capable of achieving the high working fluid temperatures needed for significant efficiency gains. This NSF EPSCoR funded, experimental research system is designed to exploit the uniquely immense solar irradiance of …

Studies Of Inner-Shell Chemistry Of Mercury Based Compounds At Extreme Conditions, Sarah Schyck

UNLV Theses, Dissertations, Professional Papers, and Capstones

It has been theoretically predicted that when mercury difluoride (HgF2) is pressurized to above 50 GPa in the presence of molecular fluorine, it will most likely transform into mercury tetrafluoride (HgF4), thus mercury will behave as a transition element at high pressure. However, there is no experimental evidence verifying this prediction yet. To begin with, the crystalline properties of pure HgF2 at high pressure were not experimentally established. In this thesis, the high pressure structural properties of HgF2 are investigated by means of synchrotron X-ray powder diffraction. Our results reveal that the predicted, ambient cubic structure of HgF2 with the …

Design And Analysis Of First And Second Order K-Delta-1-Sigma Modulators In Multiple Fabrication Processes, Shada Sharif

UNLV Theses, Dissertations, Professional Papers, and Capstones

Analog to digital converters (ADC) are an important category of electronic circuits that are required in order to convert real-world analog signals into the digital domain. One of the main trade-offs in ADC design is between data conversion speed and resolution. Delta Sigma ADCs are commonly used for high precision data conversion of low bandwidth signals such as those found in audio, industrial and biomedical applications. A major disadvantage of traditional Delta Sigma ADC architectures is that they have limited signal bandwidth and are not suited for high speed applications such as communication systems. The continuous time K-Delta-1-Sigma (KD1S) modulator …

Surface Resistivity For Concrete Quality Assurance, Stanley Tat

UNLV Theses, Dissertations, Professional Papers, and Capstones

The goal of this study was to determine the effectiveness of SRT for concrete quality assurance and to evaluate the relationship between SRT and the three chloride ion ingress methods currently used by various State DOTs. Additionally, the influence of binder type and content, concrete age, and water-to cementitious materials ratio on the experimental results were also examined.

In this study, Type V Portland and three SCMs; namely fly ash, slag, and silica fume were used. Fine and coarse, aggregates were supplied by a local quarry. To evaluate the transport properties of the studied concretes, RMT, RCPT, and ACT were …

Estimation Of The Parameters In A Spatial Regressive-Autoregressive Model Using Ord's Eigenvalue Method, Sajib Mahmud Mahmud Tonmoy

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this thesis, we study one of Ord's (1975) global spatial regression models.

Ord considered spatial regressive-autoregressive models to describe the interaction

between location and a response variable in the presence of several covariates. He also

developed a practical estimation method for the parameters of this regression model

using the eigenvalues of a weight matrix that captures the contiguity of locations.

We review the theoretical aspects of his estimation method and implement it in the

statistical package R.

We also implement Ord's methods on the Columbus, Ohio, crime data set from the

year 1980, which involves the crime rate of …

The Effect Of Instructors Training On Technology Adoption, Course Design, And Student Experiences: A Multiple Case Study Of Training Based On Tpack Or Quality Matters, Yvette Aqui

UNLV Theses, Dissertations, Professional Papers, and Capstones

The use of a Learning Management System (LMS) such as Blackboard Learn (Blackboard Learn, 2009) is a ubiquitous feature of the undergraduate experience. Despite its rapid increase in popularity and student demand for anytime, anywhere access to course materials, adoption of the LMS is slow and uneven. Some instructors also do not take advantage of some of the interactive tools in the LMS because it is complex in nature or they are unaware of the pedagogical affordances of the technology.

The purpose of this study was to explore the best ways to train faculty on how to use the LMS. …

Combinatorial Ant Optimization And The Flowshop Problem, Tasmin Chowdhury

UNLV Theses, Dissertations, Professional Papers, and Capstones

Researchers have developed efficient techniques, meta-heuristics to solve many Combinatorial Optimization (CO) problems, e.g., Flow shop Scheduling Problem, Travelling Salesman Problem (TSP) since the early 60s of the last century. Ant Colony Optimization (ACO) and its variants were introduced by Dorigo et al. [DBS06] in the early 1990s which is a technique to solve CO problems. In this thesis, we used the ACO technique to find solutions to the classic Flow shop Scheduling Problem and proposed a novel method for solution improvement. Our solution is composed of two phases; in the first phase, we solved TSP using ACO technique which …

Managing Data-Driven Change: A Model Of Unintended Deviation, Sang-Mun Ray Cho

UNLV Theses, Dissertations, Professional Papers, and Capstones

Data-driven change in hospitality gaming is desirable because of the opportunities to leverage untapped sources of rich and abundant marketing data. However, change has been difficult to implement as indicated by a lack of widespread adoption. Some have attributed these difficulties to cultural, structural, and other generic factors but these explanations fail to explain the root dynamics of data-driven change.

In this dissertation, it is theorized that data-driven change requires a particular form of social interaction, which are called analytical bonds (AB). The suggestion was that there is a sender of an analytic deliverable and a receiver that makes a …

Identifying Youth At Risk For Problematic Absenteeism Using Nonparametric Modeling: The Impact Of Youth Psychopathology And Family Environment Risk Factors, Mirae Fornander

UNLV Theses, Dissertations, Professional Papers, and Capstones

The best cutoff to differentiate problematic school absenteeism from nonproblematic school absenteeism has yet to be identified in the literature (Lyon & Cotler, 2007). Contemporary classification systems, including Multi-Tiered Systems of Support (MTSS), depend upon cutoffs to clearly define the various tiers (Jimerson, Burns, & VanDerHeyden, 2016). The current study aimed to inform the MTSS approach while also contributing to early identification, assessment, and intervention methods for those youth and families at the highest risk of problematic school absenteeism and its negative consequences. The current study identified subgroups of youth at the highest risk of problematic absenteeism, defined as equal …

How Instruction, Math Anxiety, And Math Achievement Affect Learning A Novel Math Task: Evidence For Better Instruction, Amy Jane Mcauley

UNLV Theses, Dissertations, Professional Papers, and Capstones

The primary goal of this paper is to test how math anxiety, achievement, and instruction affect learning a novel math task. Currently, most research measures achievement and math anxiety on previously learned tasks. A two-part study was proposed to measure the effects of math anxiety on learning modular arithmetic (MA), a novel math task that involves subtraction and division. Participants of varying degrees of anxiety and achievement were randomly assigned to either a specific or vague instruction condition. Participants were either taught how to solve the task or given minimal information about how to solve the task. Before moving on, …

Community College Students’ Perceptions Of Their Academic Workload, William Neff

UNLV Theses, Dissertations, Professional Papers, and Capstones

One major barrier to success, for first-time, full-time college students, is course workload (Bowyer, 2012). How students respond to their situation and the barriers they face may influence decisions they make about classes in which they should enroll or those they should avoid, completing or dropping a class during the semester, and persisting from term-to-term and year-to-year. In an effort to help students succeed, colleges often give them a specified set of core courses and a specific or even prescribed pathway to complete the “general education” requirements. These core courses such as mathematics, communication, and English, among others, taken separately …

Human Thermal Comfort In Transition Space, Asawari Anil Pawar

UNLV Theses, Dissertations, Professional Papers, and Capstones

ABSTRACT

HUMAN THERMAL COMFORT IN TRANSITION SPACES

Objective: To evaluate and identify the relationship between personal factors and the climatic conditions that influence the human thermal comfort in transition spaces and suggest solutions for adaptation of the built environment, that would encourage active and healthy living in the tourist as well as local community.

Background:

By 2050, there is a prediction that two-thirds of the world population will be living in urban areas, which would add more than 2.5 billion people living in cities (Melnikov et al., 2017). Since Las Vegas is one of the fastest growing cities in Nevada, …

Cfd Modeling Of Smoke Movement In An Atrium, Robin Wu

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this paper is to better understand the behavior of smoke movement in an atrium. Thus gives first responders and civilians in and out of building a better understanding

With the advancements of modern technology, computers and softwares make simulation models possible such as fire models to simulate fire and smoke movements. In this paper, a computational fluid dynamic (CFD) software Fire Dynamic Simulator (FDS) is used to conduct a series of atrium tests to investigate the effectiveness of smoke exhaust systems. FDS solves the Navier-Stokes equations appropriate for low speed flows (Ma < 0.3) with an emphasis on smoke, heat transport and CO2 concentrations from fires. The default turbulence model used in FDS simulation is the Large Eddy Simulation (LES), which is the solution of Navier-Stokes equations at low speed.

The compartment tested was 9 …

Biodegradable And Biocompatible Silk Fibroin For Optical Applications, Corey Bryce Malinowski

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study presents nanopatterned silk fibroin films that were fabricated using soft lithography and nanoimprinting to replicate patterns from diffraction gratings. These film’s optics were analyzed based on their light scattering potential as well as their transmittance and transmission haze using a laser light, spectrometer, and UV-Vis spectrophotometer, respectively. The patterned fibroin films all displayed similar light scattering patterns to their master patterns with some transmission haze. When using the spectrometer to measure samples, those made without any nanostructure displayed transmission of 90% and over, while those with patterns depended on the structure used. The denser a structure, like the …

Personality Patterns Of Students Who Make A Threat Of Targeted School Violence, Tawnya Michelle Ayim

UNLV Theses, Dissertations, Professional Papers, and Capstones

Although school shootings date back to the 1760’s (Dixon, 2005), recent attacks at schools in our country have raised awareness of school violence. This study investigates how students from one large school district responded to the personality pattern items on the Millon Adolescent Clinical Inventory, Second Edition after having made a threat to harm another student or staff member. Personality patterns were investigated in the overall sample, as well as within groups designated to be at a Low/Moderate risk level and High/Imminent risk level following a threat assessment. The minimal Differences between the sample for the current study and the …

Exploring Relations Between Motivation, Metacognition, And Academic Achievement Through Variable-Centered, Person-Centered And Learning Analytic Methodologies, Wonjoon Hong

UNLV Theses, Dissertations, Professional Papers, and Capstones

The three studies that comprise this dissertation examine relations between student characteristics, motivations, metacognitive learning processes, and academic achievement. Methodologically, the dissertation demonstrated the potential of multiple types of approaches

and data resource types. By employing multiple approaches including variable-centered, person-centered, and learning analytics, researchers can understand learning processes from various angles. In addition, through this triangulation by multiple types of methodological approaches, educational theories could be more thoroughly verified and supported by various empirical findings. Multiple types of data resources are related to analytical methods.

The purpose of the first paper was to examine relations between achievement goals and …

Fluid Structure Interaction Study Of The Obstructive Sleep Apnea And Surgical Treatment Using Suture-Patch Device On The Patient’S Tongue, Yang Liu

UNLV Theses, Dissertations, Professional Papers, and Capstones

Up to 14% of the U.S. population is estimated to have obstructive sleep apnea (OSA) related to obesity, and there is increased incidence occurring worldwide. While treatment with continuous positive airway pressure (CPAP) resolves airway obstruction, patient compliance is relatively low. Alternative interventions are available to treat OSA patients; however, their outcomes have had variable results. For example, current technologies have demonstrated an inability to define and treat the specific anatomical site(s) causing the obstruction, resulting in suboptimal modifications of the airway and poor control of OSA.

In the current study, a three-dimensional (3-D) fluid-structure interaction (FSI) numerical simulation has …

Efficient And Practical Composition Of Lock-Free Data Structures, Neha Bajracharya

UNLV Theses, Dissertations, Professional Papers, and Capstones

A concurrent data object is lock-free if it guarantees that at least one, among all concurrent operations, finishes after a finite number of steps. In other words, a lock free technique guarantees that some thread always makes progress. Lock-free data objects offer several advantages over their blocking counterparts, such as being immune to deadlocks and priority inversion, and typically provide high scalability and performance, especially in shared memory multiprocessor architectures.

Composition of data structures is a powerful approach to combine simple data structures to create more complex ones. It works as a building block for many advanced useful data structures. …

Performance-Based Economical Seismic Design Of Multistory Reinforced Concrete Frame Buildings And Reliability Assessment, Chunyu Zhang

UNLV Theses, Dissertations, Professional Papers, and Capstones

As the next generation of seismic design methodology, performance-based seismic design (PBSD) method requires a structure satisfy multiple preselected performance levels under different hazard levels. Optimal PBSD methods provide different strategies to design the numerous variables, including strength, stiffness and ductility of each structural component. The overall goal of this study is to develop a new optimal PBSD method for multi-story RC moment frames. This method is capable of overcoming the deficiencies of existing optimal PBSD methods and can be implemented by the U.S. design practice. The proposed method minimizes construction cost and takes the limit of member plastic rotation …

An Examination Of Perceived Leadership Behaviors And Employee Engagement In The Us Federal Government: An Exploratory Study, Jason Barker

UNLV Theses, Dissertations, Professional Papers, and Capstones

Leadership can exist in any organization or entity. It has been studied extensively and examined comprehensively. There have been various theories of what type of leadership is ideal or suitable for a group or organization. From transformational to transactional leadership, leadership styles exist that can contribute to organizations and the style they employ. Employee engagement can be based on either or both transformational and transactional leadership factors. Transformational leadership behaviors generally show an increase in employee engagement. Employee engagement has an association with job satisfaction and leadership perception. Leadership styles will be defined, in addition to factors in the employee’ …

The Roles Of Biophilic Attitudes And Auditory Stimuli Within Attention Restoration Theory, Jason B. Boggs

UNLV Theses, Dissertations, Professional Papers, and Capstones

Attention Restoration Theory indicates that interacting with nature allows one’s fatigued, directed attention to be restored. This effect has been documented and produced through directed interaction with nature, such as a walk in the park, as well as through indirect interactions (e.g., photographs). The current dissertation was designed to: 1) investigate whether and how biophilic attitudes affect the attention-restoring effects incurred from interactions with nature, and 2) extend the research on ART by assessing the impact of nature-related audio stimuli. A total of 184 participants completed an assessment of biophilic attitudes, engaged in attention fatiguing exercises, and participated in one …

Globalization And Cultural Flows: A Three-Article Dissertation Exploring Implications For Education And Culture In India, Dwight Edward Boucher

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation follows a three-article format to examine ways in which distinct manifestations of globalization have engaged and manipulated education in India as colonizing initiatives. The articles are interrelated and examine historical, societal, and individual stories related to colonial and global impositions of Western epistemological, economic, and educational forms in India. The introductory chapter outlines the broad implications of globalization and globalizing narratives, and it is intended to demonstrate that while globalization has the capacity to improve the quality and equitability of lives around the world, it also has the potential to serve as a hegemonic conduit for the continuation …

Uas-Based Object Tracking Via Deep Learning, Marc Dinh

UNLV Theses, Dissertations, Professional Papers, and Capstones

Tracking is the task of identifying an object of interest and detect its position over time, and has numerous applications like surveillance, security and traffic control. In present times, unmanned aerial vehicles (UAV) have been more and more common which provides us with a new and less explored domain, with an ideal vantage point for surveillance and monitoring applications.. Aerial tracking is a particularly challenging task as it introduces new environmental variables such as rapid motion in 3D space. We propose a new deep learned tracker architecture catered to aerial tracking.

First, a study of six state-of-the-art deep learned trackers …

Confirmatory Factor Analysis Of Oppositional Defiant Disorder Within Clinically Referred Youth, Breanna Garcia

UNLV Theses, Dissertations, Professional Papers, and Capstones

Each new edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5; APA, 2013) has been met with substantial criticism. Particularly, in DSM-5, two disorders were defined by very similar criteria. Oppositional defiant disorder (ODD) was defined as consisting of three dimensions - irritability, noncompliance, and spiteful/vindictive. Additionally, ODD has duration criteria that indicate its symptoms must be present for at least 6 months suggesting the presence of chronic irritability. DSM-5 also included disruptive mood dysregulation disorder (DMDD) as a disorder marked by the presence of chronic irritability in childhood and adolescence. The question of whether chronic irritability (i.e., …

A Framework To Capture Dynamic Traffic Trends From Historical Sensor Data, Carlos Gaviria

UNLV Theses, Dissertations, Professional Papers, and Capstones

The typical approach of increasing infrastructure to alleviate traffic issues such as congestion is becoming unviable due to limited space, high cost, and associated externalities. Control and management strategies using Intelligent Transportation Systems (ITS) seek to maximize the use of existent infrastructure. Many ITS strategies, such as the deployment of information, require or benefit from knowledge about traffic patterns and trends. This study proposes a mathematical programming formulation and solution algorithm that considers multiple time intervals for the estimation of network-wide traffic states and calculation of the corresponding transition probabilities. The proposed solution enables the determination of sections of the …

Influencing Hawai‘I Hotel Patrons To Use Reef-Safe Sunscreens, Rochelle Good

UNLV Theses, Dissertations, Professional Papers, and Capstones

The health of Hawaiian coral reefs is threatened by pollution from common sunscreen ingredients such as oxybenzone. Hawai‘i hotel patrons using sunscreens with harmful ingredients contaminate coral reefs when these products wash off while swimming or bathing. Reef-safe sunscreens are alternative sunscreens that provide effective sun protection while averting damage to coral reefs. The purpose of this research was to determine the dominant factors leading to the pro-environmental behavior of using reef-safe sunscreen and identify practices that Hawai‘i hotel operators could implement to influence patrons to engage in this behavior. This research applied an integrative conceptual framework to model pro-environmental …

Using Design Science Research To Develop A Conceptual Solution For Improving Knowledge Sharing In A Virtual Workspace, Lata Koneru

UNLV Theses, Dissertations, Professional Papers, and Capstones

Enhancements in technology have resulted in significant changes to day-to-day operations of organizations in the present day. One especially noteworthy change is the alteration in the nature of teams from being co-located, with face-to-face interaction, to virtual, with the involvement of information and communication technologies (ICT) to facilitate communication. This change in team character has had a downstream impact on a key element of an organization’s competitive edge, namely knowledge.

Overall, there is consensus that knowledge is a crucial facet of the competitive edge of an organization. Consequently, knowledge management, knowledge sharing, and organizational learning are essential components of an …

Variable Transition Time Inverters In A Digital Delay Line With Analog Storage For Processing Fast Signals And Pulses, James Kenton Mellott

UNLV Theses, Dissertations, Professional Papers, and Capstones

As the electronics industry moves forward there is an increasing need to process information faster and more accurately. High speed signals are used in scientific instrumentation, range finding devices, radar applications, and electro-optical interfaces. High-speed state of the art analog-to-digital converters are required to process these signals in real time. High frequency signals or very fast pulses are not able to be processed accurately due to either Nyquist-rate limitations or practical power consumption limits. For applications where signals are transient in nature and design size and power consumption are major factors, the proposed Variable Fast Transient Digitizer (VFTD) will be …