Digital Scholarship@UNLV (2024)

Digital Scholarship@UNLVCopyright (c) 2024 University of Nevada, Las Vegas All rights reserved.https://digitalscholarship.unlv.eduRecent documents in Digital Scholarship@UNLVen-usWed, 19 Jun 2024 02:31:52 PDT3600Salary Needed to Live Comfortably in the Mountain West, 2024https://digitalscholarship.unlv.edu/bmw_lincy_econdev/66https://digitalscholarship.unlv.edu/bmw_lincy_econdev/66Wed, 19 Jun 2024 00:17:17 PDT<![CDATA[

This fact sheet examines data on the annual salary needed to live comfortably in selected cities in the Mountain West states of Arizona, Colorado, Nevada, and New Mexico as of February 2024. A report by Smart Asset titled, “Salary Needed to Live Comfortably – 2024 Study,” provided wage data for the 99 largest cities in the United States.

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Mohit Pande et al.
Property Taxes in Mountain West Cities, 2022https://digitalscholarship.unlv.edu/bmw_lincy_hre/18https://digitalscholarship.unlv.edu/bmw_lincy_hre/18Wed, 19 Jun 2024 00:05:10 PDT<![CDATA[

This fact sheet examines data on homestead, apartment building, and commercial property tax rates for five cities in the Mountain West: Phoenix, AZ; Denver, CO; Las Vegas, NV; Albuquerque, NM; and Salt Lake City, UT). The fact sheet compares the average tax bill for homestead properties and median home values reported in “50-State Property Tax Comparison Study For Taxes Paid in 2022,” an August 2023 report from the Lincoln Institute of Land Policy and Minnesota Center for Fiscal Excellence.

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Annie Vong et al.
Risk of Climate Damage in the Mountain West, 2024https://digitalscholarship.unlv.edu/bmw_lincy_env/20https://digitalscholarship.unlv.edu/bmw_lincy_env/20Tue, 18 Jun 2024 11:33:10 PDT<![CDATA[

This fact sheet examines 2024 data on the estimated annual cost per person of damage to infrastructure, agriculture, and population from climate related disasters for the five Mountain West states of Arizona, Colorado, Nevada, New Mexico, and Utah. The original report, “States at Greatest Risk of Climate Damage - 2024 Study,” by Jaclyn DeJohn and published by SmartAsset, includes data on climate disaster risk for all 50 states.

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Taylor Volk et al.
Gender Pay Gaps in Mountain West Cities & States, 2024https://digitalscholarship.unlv.edu/bmw_lincy_econdev/65https://digitalscholarship.unlv.edu/bmw_lincy_econdev/65Fri, 14 Jun 2024 18:25:48 PDT<![CDATA[

This fact sheet examines data on the gender pay gap, or the difference in pay between male and female year-round full-time workers in the Mountain West states of Arizona, Colorado, Nevada, New Mexico and Utah. “Cities with the Largest Gender Pay Gaps” published by the Chamber of Commerce uses 2020-2021 data from the U.S. Census Bureau.

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Dre Boyd-Weatherly et al.
Introduction to Chinese Ethnic Percussion through the Concept of Free Reboundhttps://digitalscholarship.unlv.edu/thesesdissertations/4925https://digitalscholarship.unlv.edu/thesesdissertations/4925Fri, 14 Jun 2024 18:09:25 PDT<![CDATA[

World percussion is becoming increasingly important as a major teaching course in American colleges and universities. The percussion chosen may come from Africa, Latin America, East Asia, and more. However, according to the study, no American colleges and universities have conducted Chinese ethnic percussion programs. There may be several reasons for this: first, it is geographically far away. Second, the existing papers on Chinese ethnic percussion, especially in English, are too broad in their choice of arguments. For example, these papers do not consider the possibility of implementation when choosing Chinese ethnic percussion instruments. On the contrary, the choice of instruments in this dissertation incorporates the requirements of today's Chinese higher education institutions for the selection of instruments for the discipline of Chinese ethnic percussion. Third, some research works are too specific. For example, they only talk about Peking Opera percussion or percussion from a certain place in China. These types of percussion serve as an important part of Chinese ethnic percussion but do not represent the whole of Chinese ethnic percussion. The starting point of this dissertation is mainly for Chinese ethnic percussion in Chinese higher education institutions. It is in a way more representative.

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Yupeng Wei
Exploring Early Childhood/Early Childhood Special Education Personnel Preparation for Teaching Social Emotional Skills and Addressing Challenging Behaviorhttps://digitalscholarship.unlv.edu/thesesdissertations/4926https://digitalscholarship.unlv.edu/thesesdissertations/4926Fri, 14 Jun 2024 18:09:25 PDT<![CDATA[

Social emotional development is crucial for all young children. Children who develop age-appropriate social emotional skills engage in positive peer relationships, establish friendship skills, and have competent problem-solving skills. Without adequate social emotional skills, young children are at risk for detrimental long and short-term consequences such as academic failure, exclusionary practices, and school dropout. Interventions and support from well-trained teachers are essential for young children to acquire these skills. Using an explanatory mixed method approach, this study investigated how early childhood (EC) and early childhood special education (ECSE) teachers were trained to teach social emotional skills and address challenging behavior. A quantitative survey explored Pyramid Model strategies covered in coursework and implemented during fieldwork, while qualitative focus groups delved into experiences and proposed innovations for improvement. Results revealed that EC/ECSE teachers felt more prepared to provide universal supports but less prepared to address more complex strategies and interventions. In addition, EC/ECSE teachers felt underprepared to teach social emotional content upon entering the workforce. Suggestions for innovations were also discussed. The findings of this study help inform policy, practice and future research to enhance teacher preparation to effectively address social emotional content.

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Melissa Yarczower
Perceptions and Acceptance of Guestroom Technology: A Cross-Cultural Studyhttps://digitalscholarship.unlv.edu/thesesdissertations/4924https://digitalscholarship.unlv.edu/thesesdissertations/4924Fri, 14 Jun 2024 18:09:24 PDT<![CDATA[

People are using various technologies in their daily lives now. To meet the expectation of guests, many hotels have implemented different types of Guestroom Technology (GT) to improve guest satisfaction. The currently available GTs that control guestroom environments in the hotel industry include tablets, mobile applications, and voice assistants. However, tablets are out-of-date now. Prior studies examined the importance and acceptance of the other two GTs. However, the comparisons among the three GTs are limited. The research related to different types of GTs in the United States is numerous; nonetheless, there is a lack of similar studies conducted in China. Thus, the current research aims to fill this research gap by exploring consumers’ perceptions and intentions to use different types of GTs by collecting data from China and the U.S. More specifically, this study focused on guest acceptance of the two GTs (i.e., Voice Assistants and Hotel Mobile Apps), based on the Unified Theory of Acceptance and Use of Technology (UTAUT) and Protection Motivation Theory (PMT). This study also investigated other potential factors influencing their acceptance levels of these GTs, as well as differences in acceptance between the U.S. and China. From the findings, the relationship and comparison between different GTs and guest acceptance are explored based on two different countries. The results also help hospitality operators understand the different levels of guest acceptance for different types of GTs, as well as factors influencing their acceptance. Thus, they are able to make more informed decisions about implementing specific GT.

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Jueer Wang
A Dynamic Scoring Methodology for Morphing Airfoil Designs with Application to a Stalling Scenariohttps://digitalscholarship.unlv.edu/thesesdissertations/4922https://digitalscholarship.unlv.edu/thesesdissertations/4922Fri, 14 Jun 2024 18:09:23 PDT<![CDATA[

Shape Changing Airfoils (SCAs) are a developing technology with potential aircraft applications. Leading aerospace corporations are actively researching SCA capabilities. The necessity for this technology stems from the requirement of control surfaces for safe aircraft control. However, the process of testing and determining optimal SCA designs can be costly and time-consuming. While methodologies exist, they often require specific scenario examples and lack a standard approach. To address this issue, a standardized methodology is needed that can be applied to various applications and scenarios. This methodology consists of computational/experimentally produced data for airfoils, a subjective and strategic scoring equation, an algorithmic script for comparing large quantities of different airfoils, and simulations to demonstrate improvement. The conceptual scoring equation is the key element in this methodology to adapt the obtained solutions to different scenarios. This methodology was successfully created as supported by the results produced when applied to a stalling aircraft scenario. Applying this methodology to the stalling scenario involved developing multiple scoring functions based on simple efficiency ratios tailored towards desired performance metrics for stalling aircraft and then utilizing computational fluid dynamics (CFD) simulations to compare results. Six total scoring equations were developed and utilized in this study. With the starting airfoil selected as the NACA M6 airfoil, and when comparing with the 103 different airfoils present in the dataset, the NACA 6412 airfoil achieved the highest score for 3 of the 6 scoring equations. The NACA CYH obtained the highest score for 2 of the equations and the NACA 65206 airfoil obtained the high score for the last equation. Next, a commercial CFD software, Ansys Fluent, was utilized to calculate and compare which high-scoring airfoil would perform the best in a low mach stalling scenario. The proposed methodology shows promise for mitigating the dangers of aircraft stalls under these conditions. The simulations, besides for the NACA 65206 airfoil, consistently aligned with the data and decisions generated using XFOIL and the scoring script. Notably, the NACA 6412 airfoil excelled in terms of lift, nearly doubling the lift values of the initial airfoil, surpassing all other scoring equations. While the physical characteristics of the airfoils, such as swept tails and thinner bodies, may have influenced the results, further analysis is required to isolate these geometrical effects. The superiority of the NACA 6412 airfoil prompted adjustments to the scoring script, focusing exclusively on more accurate scoring equations. This refinement allows for the incorporation of a larger quantity of airfoils into the algorithm, promising even more accurate results in future assessments.

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Stone Wachs
The Floating World Around and Between; Print Culture, Racial Blurring, and Japanese Views of Black People from the 15th to the 19th Centuryhttps://digitalscholarship.unlv.edu/thesesdissertations/4923https://digitalscholarship.unlv.edu/thesesdissertations/4923Fri, 14 Jun 2024 18:09:23 PDT<![CDATA[

This paper seeks to investigate the relationship that exists within Japanese print culture (woodblock prints, newspapers, etc.) from the fifteenth to the nineteenth centuries as a means of investigating how interactions with Western empires, specifically the United States influenced perceptions and awareness of Blackness and Black people. These images and the analysis surrounding the interactions between empires help to establish what Americans perceived as the performance of “blackness” through minstrel shows and blackface performances as a means of blurring and attaching racial lines and distinctions upon the Japanese people and as a response allow for the Japanese to build an identity that refutes “blackness” while performing whiteness.By incorporating an analysis of the woodblock prints, sheet music, playbills, photographs, paintings, letters, and diary entries this study finds that having increased interactions with Western empires and their ideas of “blackness” influenced the way the Japanese people view Black people from across the diaspora. While at the same time providing a counterimage of what whiteness looks like and the notion of civilization that is attached to that racial descriptor as a means of furthering their Imperial pursuits all while attempting to find footing on the world stage.

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Angel J. Wakiihuri
Exploring the Influence of Technology-Supported Immersive Experiences: The Case of Golf Simulators as a Way of Relieving Stress in the Workplacehttps://digitalscholarship.unlv.edu/thesesdissertations/4920https://digitalscholarship.unlv.edu/thesesdissertations/4920Fri, 14 Jun 2024 18:09:22 PDT<![CDATA[

This study explores the impact of immersive technology, specifically golf simulators, on relieving work-related stress among hotel industry employees. The purpose of the current study was to examine how hotel employees perceive the use of immersive technology as a form of stress relief. The study was developed to learn whether hotel employees experience work-related stress, and if so, how they cope with it. The study also aimed to determine whether they would be interested in utilizing a golf simulator as a new form of stress relief if it were offered to them free of charge by their employer. Interviewing hotel industry employees revealed a general interest in utilizing golf simulators as an enjoyable means of stress relief. Interviews also showed that participants would be more comfortable using the golf simulator in a group setting. The overall attitude toward golf simulators was positive, and participants indicated an interest in learning how to use the technology as a mode of entertainment.

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Luka Van Der Merwe
Examining Oppressive Social Systems: Activism, Academics and Alpha Maleshttps://digitalscholarship.unlv.edu/thesesdissertations/4921https://digitalscholarship.unlv.edu/thesesdissertations/4921Fri, 14 Jun 2024 18:09:22 PDT<![CDATA[

Oppressive social systems are structures and institutions within society that systematically and unjustly restrict the rights, opportunities, and overall well-being of certain groups (Bonilla-Silva, 1997; Feagin, 2013). The current program of research aims to investigate how oppressive social systems impact individuals and explore strategies to address and counteract them. The first paper seeks to understand whether, why, and how people engage in critical action to support Black Lives Matter (BLM). The second paper examines undergraduates' perceptions of whether STEM research mentors should consider race when mentoring students from marginalized backgrounds. The final paper employs a meta-synthesis with the purpose of synthesizing studies that focus on the association between the patriarchy and close male friendships. Across all three studies, the findings are used to generate recommendations for flexible, data-driven interventions that aim to empower participants by instilling critical consciousness.

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Kristin Dee Vierra
Examining Health Literacy and Patient-Centered Communication: A Secondary Analysis of U.S. Adults with a History of Cancerhttps://digitalscholarship.unlv.edu/thesesdissertations/4918https://digitalscholarship.unlv.edu/thesesdissertations/4918Fri, 14 Jun 2024 18:09:21 PDT<![CDATA[

Racial/ethnic communities bear a disproportionate burden when examining cancer mortality and infection-related cancer incidence rates. According to the Office of Disease Prevention and Health Promotion (ODPHP), health literacy and clear communication between professionals and patients are crucial to improving health and the quality of healthcare. This study examined the relationship between personal health literacy and perceived patient-centered communication quality (PPCQ). A secondary data analysis was conducted using the Health Information National Trends Survey (HINTS) 5, Cycle 4 (2020), and STATA/BE 17.0 for Windows. The sample included respondents who have a history of cancer and have seen a healthcare provider within the past 12 months (n=579). Descriptive statistics described how health literacy and perceived PPCQ vary among different racial/ethnic groups. Most respondents self-identified as Non-Hispanic White (78.6%), male (58.3%), aged 50+ (M=67, SD=13), earned $50,000 or less annually (53.9%), and had health insurance (98.8%). This study found no statistically significant differences between racial/ethnic groups concerning health literacy. Black respondents had the highest mean PPCQ score (M=25.8, SD=3). Out of the three health literacy constructs (find, understand, and use), a multiple regression determined that the skills to find and understand information to inform health-related decisions and actions are significant predictors of PPCQ. It is incumbent upon healthcare/public health organizations and policymakers to implement system-level changes to ensure accurate, credible health information is easily accessible, distinguishable, and understandable to foster trust and self-confidence, thereby empowering individuals to improve patient-provider engagement and increase the likelihood of positive health outcomes.

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Kimberly Ann Dy Tomas
On the Synthesis of Heavy Rare Earth Solid Solutions and Their Hydrideshttps://digitalscholarship.unlv.edu/thesesdissertations/4919https://digitalscholarship.unlv.edu/thesesdissertations/4919Fri, 14 Jun 2024 18:09:21 PDT<![CDATA[

The theoretical predictions and results from the (La,Y)Hx ternary hydride solution provided evidence toward phase stability at comparatively lower pressures, as consequence the (Yb,Lu)Hx and (Tm,Lu)Hx ternary hydrides are studied here with pressures up to 25 GPa in the diamond anvil cell. The onset of an unknown feature in the XRD pattern coincides with crystallographic plane distortions in the tetragonal lattice of ytterbium hydride at their laser-heated interface, possibly driven by a solid solution of Lu-Yb. Findings in collected Raman spectra and X-ray diffraction patterns in an Ar environment suggest potential stability of the FCC and high-temperature HCP phases of Yb in the Yb-Lu solid solution as well. However, experimental results also reveal that, within the explored pressure range, no new structures or evidence of phase stability is observed for the Tm-Lu combination in either Ar or H2 atmospheres. The findings in this thesis contribute to understanding the complex behavior of similar ternary hydride solid solutions.

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Joshua R. Van Cleave
A Tale of Two Townsites: The Formative Years of the Las Vegas Valley 1902-1907https://digitalscholarship.unlv.edu/thesesdissertations/4917https://digitalscholarship.unlv.edu/thesesdissertations/4917Fri, 14 Jun 2024 18:09:20 PDT<![CDATA[

At the turn of the Twentieth Century, the waves of migration that had spurred development in the American West had not yet reached the Las Vegas Valley. The natural landscape appeared unforgiving to those who passed through for better opportunity. Although there was water, which was instrumental in establishing the Kiel and Stewart Ranches, two primary locations which had extensive areas under cultivation providing a foundation for the San Pedro, Los Angeles & Salt Lake Railroad to establish a water stop in the Las Vegas Valley. This dissertation examines the early history of the townsite development in the Las Vegas Valley from a time when there was no interest in forming a townsite through moments of highly competitive strategic moves from multiple entities. The most significant of these was the McWilliams’ Las Vegas Townsite founded by J.T. McWilliams, a trained surveyor, who in December 1904 positioned his townsite to include a portion of the rails that were already receiving passengers from Salt Lake City. McWilliams’ townsite was situated to maximize business with the railroad and the existing service to mining camps that needed supplies. It was McWilliams’ success that spurred the railroad to hurriedly plan a townsite of their own, Clark’s Las Vegas Townsite, which opened with an auction on May 15, 1905. The SPLA&SLRR’s efforts were led by First Vice President J. Ross Clark with his brother President W. A. Clark serving as the public face of the railroad that was conceived of to join the population centers of Los Angeles and Salt Lake City. For most of the first one hundred years, the dominant position of the railroad’s townsite controlled the narrative, their version of the origin story claimed the May 1905 auction was the inaugural moment in the history of the city of Las Vegas, this claim intentionally obscured the earlier townsites already in existence before the auction took place. The railroad’s auction storyline stood unchallenged as the definitive history of the founding of Las Vegas, eventually eliminating the contribution of others, including McWilliams. Through exhaustive use of property records, correspondence, business records, newspaper reporting, advertising, marketing materials and photographic evidence, this dissertation recovers a detailed history of the first year of urban settlement in the Las Vegas Valley that re-establishes the importance and success of the McWilliams’ Las Vegas Townsite and revises the history of Clark’s auction, challenging the mythic narratives of the number of attendees and lots sold. It was the McWilliams townsite, not the Clark townsite that prospered first in the rocky years of the development of the Las Vegas Valley.

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Joseph Thomson
Performance Comparison of Design-Bid-Build (DBB), Design-Build (DB) and Construction Management-At-Risk (CMAR) Methods, and Identification of Critical Success Factors for DB and CMAR in Water and Wastewater Projectshttps://digitalscholarship.unlv.edu/thesesdissertations/4915https://digitalscholarship.unlv.edu/thesesdissertations/4915Fri, 14 Jun 2024 18:09:19 PDT<![CDATA[

The United States encounters numerous challenges within the water and wastewater sectors. The American Water Works Association mandates a capital investment of $1.3 trillion over the next 25 years for the restoration and renewal of water infrastructures throughout the United States. (AWWA). To design and construct cost-effective and time-efficient water and wastewater facilities without compromising the infrastructure quality, owners are adopting alternative approaches to project delivery like Construction Management-at-Risk (CMAR) and Design-Build (DB). These approaches introduce innovation and integration into project delivery, addressing specific limitations inherent in the traditional Design-Bid-Build (DBB) method. The rise in utilization of alternative delivery methodologies has prompted a necessity for evaluating their efficacy by means of performance assessment and comparative analysis regarding cost and time efficiency. While extensive comparisons have been conducted in the highway and building sectors, there is a paucity of research in the water and wastewater sectors regarding such analyses.Therefore, this study undertook a comparative assessment of cost and schedule performance within the water and wastewater sector, examining the DBB, DB, and CMAR methods. This was achieved through a statistical analysis using tangible hard cost and schedule data collected from water and wastewater utility owners, encompassing both public and private entities. The examination revealed that DB exhibited notably superior performance in schedule growth compared to DBB and CMAR. The outcomes of the cost and schedule analysis of three delivery methods can assist owners in making well-informed decisions regarding the selection of a delivery method based on their available time and budget constraints.

Given that alternative delivery methods are relatively new in the water and wastewater sector, utility owners lack the expertise and experience required for the successful implementation of these delivery methods. Thus, it is important to investigate the DB and CMAR methods’ critical success factors so that the projects can be completed within the scheduled time and budget with better quality. Hence, this research performed an exhaustive literature review on the critical success factors of the DB and CMAR methods. Subsequently, a survey was conducted among both public and private utility owners to rank these identified factors. The primary critical success factors (CSFs) identified in this investigation for maintaining budget and schedule adherence in Design Build (DB) projects within the water and wastewater domain include project team members possessing strong technical and planning skills, fostering mutual trust among team members, ensuring clear communication flow among project participants, the design-builder's adept combination of design expertise and construction techniques, competence, experience, and delegated authority of the design-builder's project team leader, prompt conflict resolution, and the owner's swift response to design-builder's requests and instructions. Conversely, the predominant critical success factors (CSFs) identified in this research for maintaining budget and schedule adherence in Construction Manager at Risk (CMAR) projects within the water and wastewater sector encompass the design consultant's capability to develop a sound design within budget and on schedule, the contractor's robust construction management proficiency, a clear communication flow among project participants, fostering mutual trust among the project team members, project team members exhibiting strong organizational, management, leadership, and control skills, incorporation of buildability by the design consultant in the design development, a construction leader's high commitment to achieving project goals, valuable input from the contractor, early involvement of the contractor in the design stage, swift conflict resolution, and prompt response from the consultant/owner to the contractor's requests and instructions. These findings can provide valuable guidance for water and wastewater utility owners, enabling them to prioritize these factors and effectively implement projects with a high degree of success.

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Shrijan Shrestha
Physiological and Biomechanical Response to Indoor Cycling with and without the Ability to Swayhttps://digitalscholarship.unlv.edu/thesesdissertations/4916https://digitalscholarship.unlv.edu/thesesdissertations/4916Fri, 14 Jun 2024 18:09:19 PDT<![CDATA[

Introduction: Bicycles have been around since the early 19th century. Since the invention of the bicycle, it has taken on several purposes. People have used bicycles as a means of transportation, leisure, exercise, and sport. The number of individuals who participate in a cycling event per year has increased. With the increase in popularity, research related to cycling has also increased. Research related to the physiology and biomechanics of cycling are of particular areas of interest. Balance is a crucial component of understanding why we cycle a certain way. Some research has labeled balancing on a bicycle as cycling sway. However, limited research has examined the influence of balance on the physiology or biomechanics of cycling. Therefore, the purpose of this study was to understand whether or not the potential to sway influences physiological and biomechanical measures. Methods: Thirteen participants (age = 24.9 ± 6.5 years; height = 1.7 ± 0.1 m; body mass = 64.7 ± 11.2 kg; mean ± SD) volunteered for the study. The participants completed two submaximal-graded cycling tests on a stationary smart bike placed on a rocker board. One condition allowed the participants to cycle freely and maneuver the bike side-to-side (unblocked). The second condition had blocks placed in the rocker board to keep the bike stationary (blocked). The order of the conditions was counterbalanced. Prior to completing the two cycling protocols, participants performed a preferred power phase. During this phase, participants were informed of the rate of perceived exertion (RPE) scale. Participants were instructed that during this phase, their power output for an RPE of 11 (‘fairly light’), 13 (‘somewhat hard’), 15 (‘hard’), and 17 (‘very hard’) would be determined. To accomplish this, the researcher increased and/or decreased the power until the resistance felt fairly light (RPE 11) while the participant cycled for roughly one to two minutes at this power while the board was unblocked. Once the power was determined, the participants repeated this two additional times for fairly light and the researcher averaged the three trials. This process was repeated for the other three RPE intensity levels. During the two conditions, participants performed each level of intensity for three minutes and continuously (12 minutes per condition). During each condition, heart rate (bpm), rate of oxygen consumption (V̇ O2; ml·kg1·min-1), sway (radians), cadence, speed, power, and RPE (11, 13, 15, 17) were measured. For heart rate and V̇ O2, the last minute of the three minutes was averaged. For sway data, 30 seconds were recorded for each intensity. From the 30 seconds, local maximums in each direction (i.e., right, left rotations) were identified for each intensity level. The right and left sway maximums were each averaged. Results: Sway reported a statistically significant difference in the main effect of condition (p<.001). The rate of oxygen consumption, heart rate, and speed reported statistically significant differences in the main effect of intensity levels (p<.001). For sway, the VO2, heart rate, speed, distance, and cadence, there was no statistical interaction between condition and intensity (p>.05). Conclusions: Physiological measures were not influenced by the ability to sway with power matching. Sway was different between SWAY conditions regardless of INTENSITY. For the rate of oxygen consumption, heart rate, speed, and distance, values increased between INTENSITY levels (RPE 11, 13, 15, 17) for each condition. These findings are reasonable due to the graded cycling protocol and the blocked/unblocked conditions. Sway was different between conditions since the blocked condition restricted the bike’s lateral movement and the unblocked allowed sway movement. Power increased between each intensity level and since the intensity levels were performed continuously, adapting to the change in power led to increases in physiological demand. While this study allowed for any experience of cyclists, the majority of subjects were novices. Future studies should consider examining different levels of experienced cyclists to see if they respond similarly.

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Alina P. Swafford
New Observations on the Age and Origin of the Geologist Seamounts, South Hawaiian Seamount Provincehttps://digitalscholarship.unlv.edu/thesesdissertations/4913https://digitalscholarship.unlv.edu/thesesdissertations/4913Fri, 14 Jun 2024 18:09:18 PDT<![CDATA[

Investigation into seamounts that stem from intraplate volcanism—that is volcanism occurring far from plate boundaries—presents an opportunity to deconvolve processes associated with mantle compositional heterogeneities and melting dynamics. Upwelling and decompression of thermochemically anomalous mantle plumes is the primary mechanism for significant intraplate volcanism; however, many seamounts dotted across the Pacific Plate do not correlate spatially, temporally, or geochemically with mantle plume volcanism. One region of enigmatic volcanism in the ocean basins that is not clearly attributable to plume-derived magmatism are the Geologist Seamounts and the wider South Hawaiian Seamount Province (∼19°N, 157°W). Here we present merged multibeam (<100 m) and satellite altimetry bathymetric maps of the Geologist Seamounts region, new 40Ar/39Ar age determinations, and major and trace element geochemistry for six remote-operated vehicle recovered igneous rock samples (NOAA-OER EX1504L3) and two dredged samples (KK840824-02) from the Geologist Seamounts. The new ages indicate volcanism was active from 89–86 Ma and 73–72 Ma, inferring that, in conjunction with previous ages of ~83 Ma, seamount emplacement initiated near the paleo Pacific-Farallon spreading ridge and volcanism continued for at least a ~17 Ma period. Geochemical analyses indicate that Geologist Seamounts lava flows are highly alkalic and represent low-degree partial mantle melts primarily formed from a mixture of melting within the garnet and spinel stability field prior to eruption. Using the new age and chemical constraints three separate formation models for the Geologist Seamounts are tested: (1) a mantle-plume derived origin, (2) a shear-driven upwelling origin, and (3) a lithospheric extension origin. The ages and morphological characteristics infer the seamounts were likely not related to the Euterpe Plume (Musician Seamounts) or a different extinct plume. Shear driven upwelling cannot account for ~17 Ma of volcanism in a limited geographic region, nor for the oblique orientation of Geologist Seamounts relative to paleo spreading direction as shear driven upwelling forms seamount chains mirroring the direction of crustal spreading. Lastly, we build upon previous models that local microblock formation and rotation corresponded with regional lithospheric extension and the formation of the Geologist Seamounts. Using available multibeam bathymetry and magnetic reversal data, we propose the microblock was bounded by the Molokai and short-lived Kana Keoki Fracture Zones. Regional deformation and corresponding volcanism among the Geologist Seamounts associated with the microblock potentially occurred in pulses contemporaneous to independently constrained changes in Pacific Plate motion vectors at ca. 85 and 75 Ma—indicating that major changes in plate vectors can generate intraplate volcanism.

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Brandon Chester Scott
Actinide Behavior in Soft Ligand Environments and Higher Oxidation States of Neptunium in Aqueous Media with Solid-State Synthesis of Np(VII) Compoundshttps://digitalscholarship.unlv.edu/thesesdissertations/4914https://digitalscholarship.unlv.edu/thesesdissertations/4914Fri, 14 Jun 2024 18:09:18 PDT<![CDATA[

The fundamental properties of Uranium and Neptunium were investigated with Powder X-Ray Diffraction (PXRD) to study the behavior or 5f electrons with chalcogen, alkali metals, and alkaline earth metals. Two novel compounds were generated: NaCuUS3 and NaCuNpS3. There are several crystal structures that form in the family of AMM’Q (A = s-block, M = d-block, M’ = d-block or f-block, and Q = chalcogen), with oxidation states of A1+, M1+, M’4+, and Q2- ions from the family of type I compounds. Work was continued to generate the double perovskite structures in soft donor ligand environments, along with the double perovskite structure – LiBa2NpO6 in the form of A2BB’O6 (A = s-block, B = d-block, B’ = d-block or f-block, and O6 forming the remainder of the crystal lattice). A two-step synthesis from NpO2+ was carried out with ozonation followed by high temp oxidation to strip valent electrons yielding an exotic Neptunium (VII) compound for NMR analysis. NpO3 • H2O was confirmed via PXRD, however the PXRD of LiBa2NpO6 is still yet to be confirmed.

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Kelly Floyd Seeley
Regulation of Toxicity in the Pseudomonas aeruginosa Envelope Stress Responsehttps://digitalscholarship.unlv.edu/thesesdissertations/4912https://digitalscholarship.unlv.edu/thesesdissertations/4912Fri, 14 Jun 2024 18:09:17 PDT<![CDATA[

The opportunistic pathogen Pseudomonas aeruginosa forms chronic lung infections in people with cystic fibrosis (CF). In the CF lung, P. aeruginosa undergoes selection, where mucA mutations often arise. MucA inhibits the sigma factor AlgU. Mutations in mucA lead to AlgU dysregulation, resulting in a mucoid phenotype that is associated with poor CF disease outcomes. While mucA is commonly mutated, in the first part of my dissertation, I show that, paradoxically, a portion of mucA is essential in P. aeruginosa. We demonstrate that mucA is no longer required in a strain lacking algU, that the interaction between MucA and AlgU is essential, and that mucA is no longer essential in mutant strains containing AlgU variants with reduced sigma factor activity. Together, these results suggest that in the absence of MucA, the inability to regulate AlgU activity results in the loss of bacterial viability.

In searching for suppressors of mucA essentiality, I isolated a strain containing a single base pair deletion in dnaJ. DnaJ is known for its role in the heat shock response. In the second part of my dissertation, I discuss preliminary findings of this non-algU suppressor of mucA essentiality. The mutation in dnaJ resulted in a protein that contained the first 108 residues of the native protein. This strain is unable to respond to envelope stress. This data suggests that the mutation in dnaJ results in a functional change in the protein such that the ability of the cell to respond to envelope stress has been eliminated. DnaJ is highly conserved across all domains of life and may inform on crosstalk between stress responses.

It is known that mucoid cells revert to a non-mucoid state in both laboratory and CF lung environments. It is commonly thought that this reversion is driven by alginate production. In the third part of my dissertation, I show that mucoid reversion occurs even in the absence of alginate production. Additionally, upon sequencing of a few nonmucoid revertants, we found that the isolates contained secondary site mutations in algU, supporting the hypothesis that AlgU activity is the driving factor for reversion. Current work is focused on determining how alginate production affects nonmucoid reversion, as well as how common CF therapies affect this rate.

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Melissa C. Schofield Londono
Impact of Dietary Pattern Adherence and Physical Activity on Indicators of Cardiovascular Disease in Adults with and without Type 1 Diabeteshttps://digitalscholarship.unlv.edu/thesesdissertations/4910https://digitalscholarship.unlv.edu/thesesdissertations/4910Fri, 14 Jun 2024 18:09:16 PDT<![CDATA[

Cardiovascular disease (CVD) is the leading cause of death in the United States and is expected to increase with 45% of the population projected to have a CVD-related disease by 2035 (American Heart Association [AHA], 2023). While CVDs are mostly preventable, some populations are at increased risk of CVD. Individuals with type 1 diabetes (T1D) are at increased risk of CVD mortality due to higher levels of pericardial adipose tissue (PAT), coronary artery calcification (CAC), and inflammatory markers (IMs). PAT, CAC, and IMs are prognostic indicators to assess subclinical manifestations of CVD and overall cardiovascular health. Prevention strategies for CVD include a healthy diet and increased physical activity, but questions remain regarding dietary patterns individuals should follow and how much and at what intensity individuals should conduct their physical activity. These dietary and physical activity recommendations are largely focused on the general population and designed to avoid the development of type 2 diabetes (T2D) and other chronic diseases. Individuals with T1D are predominately removed from clinical and observational research studies that assess dietary patterns and physical activity measures and their associations with reduced CVD risk or associated prognostic indicators. This dissertation addresses four questions to fill gaps in current research. The first and second research questions assess how dietary pattern adherences are associated with odds of CAC progression and PAT volume, respectively. The dietary patterns include the Mediterranean-Style Dietary Pattern Score (MSDPS), Dietary Approaches to Stop Hypertension (DASH), and the Alternative Healthy Eating Index, 2010 (AHEI), which have been thoroughly investigated in the literature for the cardioprotective effects. The final two research questions investigate associations between measures of physical activity and inflammatory markers, C-reactive protein (CRP), fibrinogen, and plasminogen activator inhibitor-1 (PAI-1). The measures of physical activity included the assessment of meeting physical activity guidelines and physical activity intensities (moderate, vigorous, and joint (which is the combination of moderate and vigorous activity)) and their associations with the three IMs. These research questions were investigated utilizing data from the on-going Coronary Artery Calcification in Type 1 Diabetes (CACTI) study, which includes 652 T1D participants and 764 control participants with approximately 6 years of follow-up.

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Leigh Ann Pouncey Richardson
Treatment of Oxyanion Contaminants from Waste Brine Streams Using Halophilic/Halotolerant Microorganismshttps://digitalscholarship.unlv.edu/thesesdissertations/4911https://digitalscholarship.unlv.edu/thesesdissertations/4911Fri, 14 Jun 2024 18:09:16 PDT<![CDATA[

Brine waste streams are a current environmental issue given their high concentrations of contaminants and total dissolved solids (TDS), specifically sodium and chloride. Developing technologies that address brine treatment challenges is an essential need for water and wastewater industries. In addition to high salinity industrial wastes, there are several water treatment technologies producing brine waste streams in high volumes including reverse osmosis (RO), membranes, and Ion-exchange. With rising water demands and decreasing water supply, RO membranes will be extensively employed for potable water reuse and water desalination. Reusable ion exchange resins are also widely used to remove oxyanions contaminants from waters (e.g., nitrate, perchlorate, chromate, arsenate), for water softening, for metal separation in mining and in many other industrial applications. Direct discharge of brines to surface water bodies and soils decreases the water quality in the long term since they contain high levels of contaminants (e.g., oxyanions, nutrients, heavy metals, and trace organics) and TDS. The ecotoxicity of high TDS on agriculture, seawater species, and on soil bacteria, has been well documented and includes increased mortality rate in seagrass and reduced leaf abundance, reduce activity of microbialcommunities in soils, etc. The current research aims at contributing to the knowledge gap in the treatment of waste brines contaminated with oxyanions. The research investigates the potential for biological reduction of nitrate, chromate, and perchlorate under high TDS conditions, similar to those conditions found in waste brines, using Haloferax mediterranei and Halomonas elongata.

Hfx. mediterranei indicated an excellent performance in reducing NO3-, ClO4-, and Cr+6 in brines containing 16% to 25% NaCl (20% to 29% (w/v) total salts) under anaerobic conditions. Hfx. mediterranei grew better and reduced nitrate and perchlorate faster at higher salt levels of 20-25%, compared to 16% NaCl emphasizing the importance of the optimum NaCl level for the growth of this archaeon. The kinetic modeling results demonstrate that a first-order reaction occurred at all nitrate and perchlorate concentrations for 16% NaCl, while a zero-order reaction took place for 20-25% NaCl across all perchlorate concentrations. Cr+6 reduction by Hfx. mediterranei was found to be very effective. As seen for nitrate and perchlorate reduction, the best Cr+6 reductions were incurred at 20-25% salt content compared to 16%. An over-90% reduction was observed after 3 and 12 days for Cr+6 concentrations of 5-10 mg. L-1 and of 25 mg. L-1, respectively. Hfx. meditteranei can reduce Cr+6 much faster than nitrate and perchlorate reductions. In the testing containing concomitant nitrate and perchlorate, the sequence of degradation in the current study follows the order of NO3-→ClO4- using Hfx. mediterranei with faster kinetic rates at the optimum salt concentrations of 20 and 25%.

H. elongata demonstrated a great performance in removing NO3- (92%-100%) and Cr+6 (66%-89%) in brines containing 8% to 12% NaCl under anaerobic conditions. The optimum removal of both contaminants occurred at 8% NaCl. Increasing the NaCl level resulted in a 7% to 27% decrease and a less than 10% decrease for Cr+6 and NO3- removal. When Cr+6 and NO3- occurred together, the reduction of both was also best at 8% NaCl. The reaction order for NO3- (zero order) and Cr+6 (first order) stayed the same when the contaminants occurred co-currently.

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Yasaman Saedi
Implementation of ADAS and Autonomy on UNLV Campushttps://digitalscholarship.unlv.edu/thesesdissertations/4909https://digitalscholarship.unlv.edu/thesesdissertations/4909Fri, 14 Jun 2024 18:09:15 PDT<![CDATA[

The integration of Advanced Driving Assistance Systems (ADAS) and autonomous driving functionalities into contemporary vehicles has notably surged, driven by the remarkable progress in artificial intelligence (AI). These AI systems, capable of learning from real-world data, now exhibit the capability to perceive their surroundings via a suite of sensors, create optimal routes from source to destination, and execute vehicle control akin to a human driver.

Within the context of this thesis, we undertake a comprehensive exploration of three distinct yet interrelated ADAS and Autonomy projects. Our central objective is the implementation of autonomous driving(AD) technology at UNLV campus, culminating in the introduction of novel enhancements to essential ADAS modules. These innovations encompass a longitudinal control system, an augmented perception system, and a lane detection model. Finally, a full-scale implementation of all modules, specifically tailored for the UNLV campus environment.

The first project involved setting up an emergency braking system using 3D object detection based on monocular vision. We design a simple longitudinal PD controller that considers how close pedestrians are and triggers the brakes, which the car’s drive-by-wire system uses to control the brakes. We also augment autonomous car perception systems by eliminating a blind spot created by roadside obstacles like walls utilizing an infrastructure camera and a trajectory prediction model.

For our second project, we focus on creating a lane detection and classification model that works effectively on the challenging streets of Las Vegas. These streets pose particular challenges for existing deep learning lane detection models, characterized by suboptimal lane-to-road contrast, sparse lane markings, and extreme lighting scenarios. To overcome these obstacles, we collect data from intricate scenarios, fine-tune several advanced models, and develop a model that works better on these unique roads. We also add a lane classification branch that provides lane marking types like solid or dashed. Besides, we investigate the effect of mixed-precision technique in reducing the inference time.

In our final project, we bring self-driving technology to the UNLV campus. We employ the Autoware Universe software stack and adapt it to our specific sensor setup and vehicle interface. Our platform relies on HD maps for localization and navigation. It uses a 3D LiDAR object detection model for pedestrians, vehicles, and other dynamic objects. Finally, it uses a model predictive controller to implement the generated motion command. Our equipped vehicle can navigate autonomously within the campus while adhering to traffic rules.

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Zillur Rahman
Compassion, Oxytocin, and Simulation Experiences Among Prelicensure Nursing Studentshttps://digitalscholarship.unlv.edu/thesesdissertations/4907https://digitalscholarship.unlv.edu/thesesdissertations/4907Fri, 14 Jun 2024 18:09:14 PDT<![CDATA[

Background: Compassion is a core competency and the philosophical foundation of nursing. Previous studies demonstrated that uncompassionate nursing care was associated with increased patient morbidity and mortality, prolonged illness and recovery, and missed care opportunities. However, it is unknown whether prelicensure nursing education contributes to greater compassion levels among prelicensure nursing students (PNSs). Aims: These studies addressed three research aims: (1) Describe and compare levels of compassion in first-term and last-term PNSs, (2) Determine the effects of a compassion-inducing simulation event on compassion in PNSs, as measured through a survey and biological measurement, and lastly, (3) Investigate the relationship between self-reported levels of compassion and salivary oxytocin (sOXT) levels in PNSs.

Methods: Two studies were used to address the research aims: (a) Study 1 assessed and compared trait-compassion levels among first- and last-term nursing students in prelicensure programs in Nevada and Washington via the administration of a self-report survey, and (b) Study 2 examined the difference in state-compassion levels before and after a compassion-inducing simulation event in PNSs at the University of Nevada, Las Vegas. State-compassion levels were measured using the Sinclair Compassion Questionnaire – Learner, while trait-compassion was measured using the Compassion Scale. In Study 2, participants were asked to provide a 4 ml passive drool saliva sample into a polyethylene tube four times—before and after a control activity and before and after a compassion-inducing event. These saliva samples were analyzed for levels of oxytocin (OXT). An independent samples t-test compared compassion levels between first- and last-term PNSs. A repeated measures analysis of variance (ANOVA) was performed to compare state-compassion and sOXT levels over time, before and after the control and simulation events. In addition, Pearson’s correlation analysis was used to test whether any change in state-compassion levels was associated with any change in OXT levels.

Results: Data for Study 1 indicated no significant difference between trait-compassion in first- and last-term PNSs. There was a significant difference between male and female participants, with females having statistically higher compassion than males (p<.05). Study 2 revealed a statistically significant inverse correlation between sOXT and SCQ-L over four time points. Additionally, SCQ-L significantly increased over time, while sOXT significantly decreased.

Discussion: Findings from this research will enhance understanding of compassion levels among PNSs and whether nursing education and a compassion-inducing simulation event improve compassion levels. Considering the necessity of compassion for providing quality patient care and that nursing education is the pathway for individuals to become nurses, these studies inform future research evaluating compassion-promoting programs or simulations in prelicensure nursing education programs.

Conclusion: Compassion did not change during prelicensure nursing education when comparing first- and last-term PNSs. Nurse educators must work to develop, implement, and evaluate means to positively impact compassion among PNSs. Such methods should include robust study design, incorporate events or interventions explicitly aimed at the experience of compassion, and facilitate compassion development in new nurses. Such efforts and activities will improve the quality of life for nurses and patients and increase longevity and compassionate nursing care for the public.

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Shelley L. Price
Numerical Investigations of sCO<sub>2</sub> Compressor Aerothermodynamics Using a Streamline Curvature Based Throughflow Methodhttps://digitalscholarship.unlv.edu/thesesdissertations/4908https://digitalscholarship.unlv.edu/thesesdissertations/4908Fri, 14 Jun 2024 18:09:14 PDT<![CDATA[

Supercritical carbon dioxide (sCO2) has emerged as a promising working fluid for the Brayton power cycle, offering enhanced efficiency due to the high density and low viscosity of carbon dioxide (CO2) near the critical point. A critical component of the sCO2 Brayton cycle is the turbomachinery, namely the compressor, which significantly contributes to the efficiency enhancement in the sCO2 Brayton cycle owing to reduced compression work requirements. Its primary function involves elevating the fluid's pressure, effectively priming it for the subsequent heat addition process from a thermal energy source. However, despite its advantages, challenges persist that need to be addressed before the adoption of the technology. These challenges stem from factors such as elevated operational pressures and the complex real gas behavior of CO2. While CO2 in its supercritical state boasts favorable properties, its thermophysical and transport properties exhibit increased sensitivity to variations in temperature and pressure, particularly in proximity to the critical point. This not only introduces complexities in the operation of sCO2 compressors but also in their analysis. All these considerations must be carefully addressed during the compressor's design to accommodate the diverse behaviors that sCO2 can manifest under both design and off-design conditions.

This study aims to numerically investigate the aerothermodynamic phenomena inherent in compressors utilizing sCO2 within the framework of sCO2 Brayton power cycles. This effort is prompted by the demand to develop novel and adaptable power cycles that align with the requisites of sustainable energy generation. Traditional analyses of sCO2 compressors have predominantly encompassed meanline analysis and computational fluid dynamics (CFD) evaluation. Although meanline methodologies offer crucial preliminary design insights, transitioning to comprehensive CFD analysis faces challenges due to complex physical phenomena at operational conditions. This is particularly notable in scenarios where compressors exhibit enhanced efficiencies, demanding computationally intensive numerical analysis.

To address this complexity, this dissertation places its focus on the development of a comprehensive throughflow model tailored for sCO2 compressor analysis. The model is designed to adeptly manage the intricate fluid dynamics and thermodynamics of sCO2. Enhanced and efficient numerical throughflow models for sCO2 compressors can advise on the development of more efficient compressors with enhanced aerothermodynamic performance. This study presents the application of a two-dimensional (2D) streamline curvature-based throughflow method, considering real gas thermophysical properties, to analyze a centrifugal compressor operating with sCO2 at near-critical onditions. The method's validity is established through comparisons of the predicted performance characteristics with those of an sCO2 compressor available in open literature and by comparing the performance and flow field predictions from CFD analysis. The streamline curvature-based throughflow method demonstrates its effectiveness by achieving significant agreement between the flow field and performance characteristics, both at design and off-design conditions. Where pressure ratio and isentropic efficiency predictions were within 0.3522% and 6.63% , respectively, compared to CFD simulations.

Furthermore, a study on the impact of the operational conditions of the compressor emphasized the importance of accounting for variations in intake conditions, as even small changes in temperature and pressure near the critical point of CO2 can significantly affect the compressor's performance and operability. An investigation of the impact of compressor intake conditions on the aerodynamic performance of compressors is then conducted employing the throughflow analysis method, considering various intake conditions including subcritical vapor, supercritical vapor, supercritical liquid, and near-critical conditions. This consideration is essential for both sCO2 compressor design, and safe and stable operation, especially when operating at near-critical conditions.

While accounting for the impact of intake conditions is crucial, an interesting trend emerged regarding the computational resources needed during numerical analysis in the near-critical region, holding significant numerical implications. Specifically, at near-critical conditions, there was a maximum increase of 3201% in the computational run-time required for CFD-based computations compared to superheated conditions. In contrast, throughflowbased computations experienced a maximum increase of only 164% in run-time, primarily due to the numerical under-relaxation needed. This underscores the efficiency of the throughflow analysis, particularly for the early design phase of sCO2 turbomachinery, where conducting numerous CFD studies at near-critical conditions may not be practical due to higher computational resource requirements.

Additionally, a non-equilibrium condensation model based on classical nucleation theory was adapted and coupled to the throughflow model to account for the condensation of CO2 during expanding conditions in a converging nozzle to analogize the acceleration and expansion experienced by sCO2 to conditions similar at compressor blade leading edges.

The streamline curvature-based throughflow analysis method proved to be a valuable tool for predicting sCO2 compressor behavior, particularly under near-critical conditions. While challenges and limitations exist, this approach, combined with experimental and CFD analyses, offers a comprehensive framework for advancing designs and understanding of sCO2 compressors in the context of sCO2 based power cycles.

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Victor Quintanilla
Optimized Indoor Temperature in Office Buildings Through Personalized Thermal Comfort Modelinghttps://digitalscholarship.unlv.edu/thesesdissertations/4905https://digitalscholarship.unlv.edu/thesesdissertations/4905Fri, 14 Jun 2024 18:09:13 PDT<![CDATA[

Building occupants experience varying thermal comforts at static indoor set-point temperatures due to variances in preferences, needs, and activities, both within and among individuals. Despite advancement in smart building control systems, many building occupants remain dissatisfied with indoor temperatures. This study developed and created an optimization model to predict the optimized indoor temperature preferences in multiple-occupancy settings. To achieve this, personalized thermal comfort models for each occupant in a multiple occupancy space were developed. The personal comfort models serve as the foundation for predicting their individual thermal preference and developing indoor temperature optimization model. When predicting the individual thermal preference, a personalized thermal comfort model incorporates both physiological signals (such as heart rate, skin temperature, and skin conductance) and environmental parameters (such as air temperature, relative humidity, and CO2 levels). Data was collected through an experiment conducted in an office building and was used to train the model using different machine learning algorithms to identify the most reliable personalized predictive model. The results show that each person possesses an effective classification model that accurately predicts their preferences in personal comfort models. The developed personal comfort models served as the crucial inputs for optimization model. After developing these personal comfort models, optimization methods were employed using three different probability approaches, including average of the three subjects predicted probabilities, majority values selection, and posterior probability approach in Naive Bayes classifier to determine the optimized indoor temperature and thermal preferences based on three different thermal preferences predictions from personal comfort models. The proposed indoor optimization model will contribute to providing a thermally comfortable indoor environment while minimizing unnecessary energy consumption.

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Raviteja Patchava
Engineered Biomass-Derived Carbon Adsorbents for Targeted Contaminant Remediation from Aqueous Environmentshttps://digitalscholarship.unlv.edu/thesesdissertations/4906https://digitalscholarship.unlv.edu/thesesdissertations/4906Fri, 14 Jun 2024 18:09:13 PDT<![CDATA[

Porous carbon adsorbents like biochar (BC) are produced from waste biomasses like wood chips, animal litter, nut shells, dried grass, etc. to be used in a multitude of applications like gas capture, soil amendment, water treatment, electrode materials, etc. In water treatment, carbon-based adsorbents have been mainly used to physically or chemically adsorb contaminants depending on the adsorption mechanism. However, BCs in their raw state do not have the capability of absorbing high amounts of contaminants and need to be activated/ modified for the pore network to broaden and adsorb the contaminants with better efficiency.

The scope of this dissertation is to suitably engineer and enhance carbon-based adsorbents using physical and chemical modification techniques to target various contaminants commonly found in water like heavy metals, volatile organic compounds, charged organic dyes etc. and successfully adsorb them. The adsorption of the contaminants is maximized by tailoring the modification method to fit the adsorption mechanisms of each of the contaminants, thereby maximizing the effect of adsorption between the adsorbent and the contaminant.

In this dissertation, BCs were initially produced with varying biomasses and pyrolysis conditions to identify the production and biomass factors affecting the adsorption capacity of the BC. The effect of varying the pyrolysis temperature was also studied to understand the production of BCs based on pyrolysis temperatures. Then, trichloroethylene (TCE) and tetrachloroethylene (PCE) adsorption experiments were conducted to identify the best performing BC. Furthermore, the identified BC was then modified using a novel alkali intercalation and acid exfoliation method to enhance the total surface area (TSA) and microporous surface area (MSA) of the BC. The alkali-acid intercalated-exfoliated (ICE) BC modification involves the usage of various alkali hydroxides to intercalate the alkali ion between the carbon layers of the BC and then exfoliate the layers with various acids to form the alkali metal-based salts which causes an expansion in the carbon layers, triggering a significant increase in the TSA and MSA of the BC. To assess the effectiveness of the modification and enhancement in the physicochemical properties of the BC, malachite green (MG) dye adsorption experiments were conducted. It was observed that this modification greatly increased the TSA and MSA of the BC, thereby increasing the MG dye adsorption capacity of the BCs significantly.

Additionally, a few best performing unmodified and chemically modified BCs were chosen to fabricate a metal-organic-framework (MOF) and BC composite. MOFs are known coordination polymer materials that have metal ion clusters attached together by organic chained linkers to create a continuous coordination polymer capable of ion exchange within heavy metal contaminant remediation. Therefore, the physical addition of MOF particles to the BC’s surface adds chemical functionalities that have ion exchange, electrostatic attraction, and chemical complexation capabilities toward the contaminants in addition to the BC’s surface sorption potential. This chemisorption enhancement by the MOF-BC composites was assessed by conducting lead and chromium heavy metal adsorption studies to detect that the MOF-BC composites remove a higher amount of lead compared to all the other BCs.

The outcomes and methodological developments attained in this dissertation offer a compelling approach for targeted modification of carbon adsorbents like BC for aqueous remediation applications and can be used by material scientists and environmental engineers to implement effective water remediation techniques.

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Suraj Venkat Pochampally
Properties of Ultra–High Performance Concrete Using Plaster Sandhttps://digitalscholarship.unlv.edu/thesesdissertations/4904https://digitalscholarship.unlv.edu/thesesdissertations/4904Fri, 14 Jun 2024 18:09:12 PDT<![CDATA[

In this study, the fresh, bulk, transport, volumetric stability, and durability properties of several ultra-high performance concretes (UHPCs) containing an optimized gradation of concrete and plaster fine aggregates were evaluated. The supplementary cementitious materials (SCMs) class F fly ash and silica fume were used to replace a portion of the Portland cement in the studied UHPCs in replacement proportions ranging from 5 to 30% of cement weight. Plain and steel fiber-reinforced iterations of each UHPC mixture were evaluated to determine the role of steel fibers on the properties of the UHPCs. The fresh and bulk properties investigated were flow, compressive strength, elastic modulus, flexural strength, and unit weight. The transport properties were evaluated for absorption, permeable voids, rapid chloride permeability, andsurface resistivity. The investigated volume stability properties included linear shrinkage and restrained shrinkage. Lastly, the resistance to freezing and thawing with deicing salts was used to evaluate durability. The results of this research study revealed that the inclusion of SCMs improved fresh, bulk, transport, and durability properties while worsening volume stability properties. Improvements and impairments in the aforementioned properties tended to increase in magnitude with increasing proportions of silica fume more so than with increasing proportions of fly ash. Moreover, improvements and impairments experienced in the evaluated UHPCs due to proportioning of SCMs, as well as the difference in effect between the silica fume and fly ash, could be attributed to the pozzolanic reactivity and particle dimensions of the SCMs. The addition of steel fibers led to worsened fresh properties, and improved bulk, volume stability, and durability properties in the form of resistance to freezing and thawing with deicing salts. Additionally, the inclusion of steel fibers had negligible effects on the transport properties of the studied UHPCs.

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Andrew Pappas
Pantograph Carbon Strip Degradation Monitoring – Pulsed Power Application Using Electromagnetic Dot Sensorhttps://digitalscholarship.unlv.edu/thesesdissertations/4902https://digitalscholarship.unlv.edu/thesesdissertations/4902Fri, 14 Jun 2024 18:09:11 PDT<![CDATA[

The weakest link in powering high-speed rail locomotives is the carbon strip of a pantograph collector which makes physical contact between the overhead power line and the electrical supply wires of the locomotive. A means of detecting and distinguishing between static degradation effects of the carbon strip by monitoring the locomotive’s input current line is presented. It was hypothesized that the transient nature of the current flow in the locomotive’s input power line and hence the magnetic field it generates can be used to characterize and monitor the carbon strip’s integrity. Further, it was hypothesized that the electromagnetic dot (EM dot) sensor is sensitive enough to monitor the magnetic field and changes in the magnetic field generated by the current in the locomotive’s input power lines.

A pulsed-power carbon strip degradation test stand was designed, built, and tested based on static degradations. The test stand was designed to operate in single-pulse mode and multi­pulsed mode. Short, high-energy pulses generated in the test stand were used to monitor the changes on the carbon strip. Driven by a 5 kV DC source, a 3.3 µF capacitor (rated at 25 kV DC) releases its energy to the trainload resistor, RL (1 Ω < RL < 7.5 Ω) by way of a discharge tube switch (operating in a self-breaking mode) in series with the carbon strip. Based on Paschen's effects, the self-breaking switch exhibits closure at desired breakdown voltage as dictated by the tube pressure. An extensive circuit theory (with MATLAB), an independent computer-aided design, analysis, and circuit simulation tool (LTspice), and an in-line current measuring resistor were used to study the charge and discharge properties of the test stand and to corroborate experimental results using the electromagnetic (EM) dot with respect to theory and simulation. The EM-dot is a compact UNLV patented time-varying and, with initial transients, DC measuring electric and magnetic field sensor. All four studies showed reasonably good agreement.

The EM dot was sensitive enough to distinguish the static groove faults from the carbon strip in its new, unblemished state to its shorted state (including other resistance of different grooves) for trainloads less than 2.2 Ω. The carbon strip electrical resistance ranges between 3 mΩ ≤ Rc ≤ 28 mΩ, where the electrical short state occurs at Rc = 3 mΩ and the new, unblemished state occurs at Rc = 28 mΩ.

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Olufemi Olubode
Examining the Spatial Periodicity of Force Chains and Strain Localization in Polycrystal Modelshttps://digitalscholarship.unlv.edu/thesesdissertations/4903https://digitalscholarship.unlv.edu/thesesdissertations/4903Fri, 14 Jun 2024 18:09:11 PDT<![CDATA[

Shear strain localization is typical in deforming rocks and is vital for developing faults and tectonic boundaries. There are various proposed drivers of shear localization (temperature, fluid, phase transformation, and microstructure); we will explore the effects of elastic heterogeneity (a microstructural influence) on shear localization in polycrystal models. Elastic heterogeneity can lead to varied stress states in material and drive shear localization. Previous simulations of elastically heterogeneous polycrystal models have shown that the stress distribution can be described as forming an anastomosing pattern of high-stress streams parallel to the compression direction. This anastomosing patterning resembles force chains; linear, high-stress features that form parallel to compression in granular materials. Findings in the literature suggest that buckling force chains govern shear band formation in granular materials; thus, viewing polycrystalline materials through a force chain lens may bring new insights. In previous simulation work, the initiation of plastic deformation produced shear bands with a spacing proportional to the density of patterning in the stress distribution and with displacements that are inversely proportional to the number of shear bands that formed. We continue this work by attempting to quantify the spacing of force chains and shear bands in 2D simulations of polycrystals using the Autoperiod method. The Autoperiod method can measure the dominant periodicities of a signal and is adapted to capture spatial periodicities of features in the stress and strain distributions from polycrystalline models. This quantification may allow us to make testable predictions about the distribution of stress and strain localization in real materials.

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Richard D. Panduro-Allanson
Does Maternal Mental Health (Anxiety and Depression) Negatively Impact Exclusive and Continued Breastfeeding Practices?https://digitalscholarship.unlv.edu/thesesdissertations/4900https://digitalscholarship.unlv.edu/thesesdissertations/4900Fri, 14 Jun 2024 18:09:10 PDT<![CDATA[

Exclusive and continued breastfeeding practices are the optimal source of nutrition for an infant's well-being, cognitive growth, and development and have positive health outcomes for the mother too. Anxiety and depression are common perinatal mental health conditions associated with early breastfeeding interruption. However, Nevada lacks data on perinatal mental health and its influence on breastfeeding practices. The objective of this study was to assess whether maternal mental health (anxiety and depression) impacts exclusive and continued breastfeeding practices in Clark County, Nevada. A cross-sectional survey was conducted with 358 mothers having children 0-23 months old and residing in Clark County, Nevada. A descriptive, bivariate, and multivariate logistic regression analysis between breastfeeding outcomes and self-reported anxiety and depression symptoms adjusted by co-variables was performed. The prevalence of exclusive breastfeeding for infants under 6 months old was 35.0% (n=123), and the continued breastfeeding rate for children 7-23 months old was 50.9% (n=224). Decreased exclusive breastfeeding was independently associated with depressive symptoms (AOR = 0.13, 95% CI: 0.03- 0.51) and the interaction between both anxiety and depression symptoms (AOR= 0.15, 95% CI: 0.04-0.57). Decreased continued breastfeeding was significantly associated with anxiety symptoms(AOR=0.41, 95% CI: 0.18-0.91). We found that maternal anxiety and depression are independent risk factors for decreasing the frequency of breastfeeding practices among mothers of children under two years old in Clark County, Nevada. Hence, evidence-based interventions should be implemented to reduce maternal anxiety and depression, as they are linked to breastfeeding success and the well-being of mothers and children.

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Smriti Neupane
A Multiple Case Study Examining the Role of Racism in the Development of Relationships between White Teachers and Students of Colorhttps://digitalscholarship.unlv.edu/thesesdissertations/4901https://digitalscholarship.unlv.edu/thesesdissertations/4901Fri, 14 Jun 2024 18:09:10 PDT<![CDATA[

The purpose of this case study was to investigate how white female teachers establish relationships with their Students of Color – students who often have backgrounds very different from their own (race, ethnicity, religious affiliation, traditions practiced, socio-economic status, etc.). While the teaching workforce is predominantly white and female, the student body increasingly consists of students who are currently classified as minorities. I used the multiple case study method with seven selected teachers who self-identified as white and female. This study utilized Critical Race Theory (CRT), as identified by Ladson-Billings and Tate (1995), for its theoretical framework. Ladson-Billings was one of the first individuals to introduce CRT to the field of education. I interviewed seven white female teachers regarding their interactions in the classroom with Students of Color and with white students to identify possible indicators of racism (intentional as well as unintentional). I also examined how such indicators affect the student-teacher relationship. The focus of the study was to explore differences in the relationships between white teachers and Students of Color. I chose to conduct my research using a qualitative procedure, specifically a case-study format. I collected data using interviews, teacher journals, and a focus group session. I used convenience sampling, interest surveys and emails to narrow down my selected group of seven white female schoolteachers. Reasonable efforts were made to interpret the data without bias, relying on discussions of findings with experts in the relevant field of research to minimize personal preconceptions.

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Skeeter Newman
The Impact of the COVID-19 Pandemic Response on Food Safety Violations Observed in Southern Nevada Food Establishmentshttps://digitalscholarship.unlv.edu/thesesdissertations/4899https://digitalscholarship.unlv.edu/thesesdissertations/4899Fri, 14 Jun 2024 18:09:09 PDT<![CDATA[

Food poisoning is a common term used to describe what is actually foodborne illness. Despite the fact these illnesses can become deadly, foodborne illnesses are endemic and common in the United States. Nonetheless, they are completely preventable simply by following proper food safety procedures. The Food and Drug Administration identified the most common foodborne pathogens responsible for most foodborne infections, as well as the five risk factor categories to target in order to decrease the risk of cases and outbreaks.

To ensure foodborne outbreaks and cases are prevented, health authorities are tasked with conducting routine inspections on permitted food establishments. In Clark County, food establishment inspections are conducted by environmental health specialists and assess food safety risk factors. Food establishments are expected to be in compliance with the Southern Nevada Health District’s food regulations. A lack of compliance can result in fees, reinspections, and even closures. This entire process aims to hold food establishments accountable and reduce the risk of foodborne illness in the public.

The COVID-19 pandemic changed the way many operations functioned. Even routine human behavior was changed simply due to the fear and the unknown surrounding COVID-19. Furthermore, mandates, executive orders and emergency directives enacted by the Governor of Nevada forced businesses around the state to adapt their operations and business models. Nonetheless, in Southern Nevada, environmental health specialists continued to conduct the same routine inspections of permitted food establishments. This means there was accurate data demonstrating the food safety of food establishments in Southern Nevada prior to and after the pandemic response was initiated.

The objective of this study was to identify changes in violations observed during routine inspections of permitted food establishments within Southern Nevada after the pandemic response was initiated. To accomplish this, we analyzed inspection reports from 2019 and compared them to inspection reports from April 1st 2020 to December 31st 2020. We determined if there was a statistically significant change in the mean number of violations observed within the two analysis periods using parametric and bootstrap resampling statistics to ensure accurate results. We further analyzed the data to determine if changes were observed more often in specific violation categories.

All violation categories including total, critical, major, and good food management practices (GMP) resulted in an improvement in mean violations prior to and post-pandemic response. The largest change was observed in the total violations category, with a 0.399 improvement. The smallest change was observed in the critical violation category, with a 0.071 improvement. While all categories resulted in an improvement that was statistically significant using both parametric and bootstrap methods, all improvements were less than one violation. This calls to address the potential importance of this less than one violation improvement in regard to the impact the COVID-19 pandemic response had on food safety. While this small improvement may not be enough to determine future preparations in food safety, it is important to continue studies on this topic in order to get a better understanding of those extreme facilities that had large improvements or significant worsening of scores during this time, as well as the specific violations with the most amount of change observed.

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Samantha Morales
Evolving Expressions of Trauma in James Joyce, Jean Rhys, and Caryl Phillipshttps://digitalscholarship.unlv.edu/thesesdissertations/4897https://digitalscholarship.unlv.edu/thesesdissertations/4897Fri, 14 Jun 2024 18:09:08 PDT<![CDATA[

Evolving Expressions of Trauma articulates ways that dynamic, changing theories of trauma can provide a language and conceptual space to examine innovative modes and means of expression in Modernist novels and in later, post-colonial and experimental novels. This dissertation asserts that as trauma theory has expanded to encompass and describe different types of traumata, including the mundane, the insidious, and empathetic, it has provided a scaffolding for studying difficult, even impenetrable works from the Modernist period and beyond. The works examined here are strategically selected to demonstrate scope and particularity in the growth of trauma theories and their potential applications to literature. They include James Joyce’s A Portrait of the Artist as a Young Man and Ulysses; Jean Rhys’s Good Morning, Midnight, Voyage in the Dark, and Wide Sargasso Sea; and Caryl Phillips’ novel The Nature of Blood. Methodologically, Evolving Expressions of Trauma provides first an examination of trauma theory since its inception as a purely neuro-anatomic set of observations through to its contemporary existence as a full-fledged psychoanalytic framework to orient a thorough examination of the selected novels as ones of trauma. Each of the subsequent chapters point toward formal and discursive strategies that indicate, and implicate, specific types of traumata in the authors’ formation and expression of their character’s narratives. This study resolves and looks forward with a final explanation of the usefulness of trauma theory as a set of analytical standards and with a warning regarding its increasing popularity and the potential for reckless, unethical employment in reading and writing literature.

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Sean M. McCray
“And I’m Going to Destroy You.”: Persona and Gender Performativity in Ernest Hemingway’s <em>The Garden of Eden</em>https://digitalscholarship.unlv.edu/thesesdissertations/4898https://digitalscholarship.unlv.edu/thesesdissertations/4898Fri, 14 Jun 2024 18:09:08 PDT<![CDATA[

While debate of Ernest Hemingway’s authorial masculine persona in connection to The Garden of Eden has been a point of interest in literary scholarship, no single work has tied together theory of gender performativity to persona. A borderline parodic display of masculine adventure has encouraged a one-dimensional view of Hemingway, who is viewed by audiences as the pinnacle of masculinity. However, this image is complicated by the publication of Eden, which reveals an author interested in gender and sexual identity fluidity. Rarely has a single text called into question so controversially an author’s public image. Eden showcases an empathetic side of Hemingway unfamiliar to readers. The tenderness in Hemingway’s prose of queer characters reveals an author overflowing with sympathy, yet eventually succumbing to the protection of his own culturally created masculine persona.Using Judith Butler’s theories of gender performativity and compulsory heterosexuality, in connection with Jack Halberstam’s notion of the female masculine, this research close read how Eden’s main characters enact gender fluidity by their physical stylings, gender role reversals, and queer relationships. My research argues that gender confusion, which began with “Summer Girl”, haunted Hemingway, leading to the creation of the masculine authorial persona he is remembered for today. As such, Catherine and David are read as manifestations of Hemingway’s own gender divergence. Undertaking such study is vital to Hemingway scholarship in order to understand the nuanced threads of identity, desire, and gender presented within Eden. My research explores the circular nature of gender performativity and masculine persona creation in the author’s controversial novel.

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Nicole Minton
Profiles of Cross-Domain Motivational Beliefs: Relations With Engagement and Genderhttps://digitalscholarship.unlv.edu/thesesdissertations/4895https://digitalscholarship.unlv.edu/thesesdissertations/4895Fri, 14 Jun 2024 18:09:07 PDT<![CDATA[

A central tenet of expectancy-value theory is that individuals’ relative expectancies and values across multiple academic domains influence their achievement-related outcomes. However, few studies have investigated how expectancy-value beliefs in multiple domains combine within individuals and how such motivational configurations are related to engagement. In this study, a person-centered approach was employed to identify and evaluate naturally occurring combinations of motivational beliefs among 3,928 fourth-grade students. Leveraging TIMSS and PIRLS database of 2011, I examined profiles of students’ math, reading, and science self-concept and interest value and their relations with engagement in these domains. Additionally, I examined gender as predictors of profile membership. Results revealed five expectancy-value profiles, which displayed evidence of self-differentiation and subject prioritization (e.g., High Math/ /Moderate Reading and Science). Additionally, reading, math, and science engagement were found to significantly differ across the profiles in theoretically-consistent ways, and gender predicted profile membership.

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Alireza Maghsoudlou
Application of Biochar for Antibiotic-Free Nutrient Recovery from Source-Separated Human Urinehttps://digitalscholarship.unlv.edu/thesesdissertations/4896https://digitalscholarship.unlv.edu/thesesdissertations/4896Fri, 14 Jun 2024 18:09:07 PDT<![CDATA[

In recent years, the application of biochar as a soil amendment has gained attention as a potential solution for nutrient management and environmental remediation. Biochar, a carbon-rich material produced through the pyrolysis of biomass under oxygen-limited conditions, exhibits unique physicochemical properties making it an effective sorbent for nutrients and contaminants. Its high surface area, porosity, and stability provide an ideal matrix for nutrient retention and release, as well as the immobilization of pollutants. One area of particular interest is the application of biochar for nutrient recovery from source-separated human urine. Source separation of urine has gained momentum as a sustainable sanitation practice, as it allows for the separate collection and treatment of urine, which is rich in essential plant nutrients such as nitrogen, phosphorus, and potassium. However, the widespread use of antibiotics in livestock production and human healthcare has led to the presence of antibiotic residues in animal manure and wastewater, posing a threat to ecosystems and contributing to the development of antibiotic resistance. This dissertation research unveils the potential of biochar in addressing the challenges associated with nutrient management and the risks associated with antibiotic release to the environment.

This research includes antibiotics from five different classes: macrolide (azithromycin (AZ)), fluoroquinolones (ciprofloxacin (CPX)), sulfonamides (sulfamethoxazole (SMX)), tetracycline (tetracycline (TC)), and aminopyrimidine (trimethoprim (TMP)). These antibiotics are widely used for medical and veterinary purposes and are frequently found in human urine, wastewater effluent, surface water, and drinking water. There are three major research tasks where batch adsorption experiments were conducted using virgin and/or modified biochar prepared from oak wood (OW), paper mill sludge (PMS), and/or sewage sludge (SS) to elucidate the effects of adsorption time, pH, and adsorbent dose. Various adsorption isotherm models (Langmuir, Freundlich, Temkin, and Redlich-Peterson) and kinetic models (pseudo-first order, pseudo-second order, Elovich, and intra-particle diffusion) were employed to describe the experimental results. Brunauer–Emmett–Teller analysis, X-ray diffraction (XRD) spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy (EDS), and Fourier transform infrared (FTIR) techniques were used to characterize the physical and chemical properties of the biochar.

The first task aimed to investigate the simultaneous adsorption of nutrients and antibiotics on biochar under different environmental conditions using virgin OW and PMS biochar. Hydrogen bonding and π-π interactions were identified as potential adsorption mechanisms. The findings suggest that biochar can simultaneously adsorb nutrients (43.30–266.67 mg/g) and antibiotics (246.70–389.00 μg/g). Lower solution pH (< 5) was better for antibiotic adsorption, while higher solution pH (> 5) favored nutrient recovery. Also, desorption of the antibiotics was observed, which might raise concerns due to possible environmental release of antibiotics. To improve antibiotic adsorption selectivity, there is a need to go beyond pristine biochar, such as biochar with surface modification.

In the second task, non-traditional modifiers, dimethyl sulfoxide and deep eutectic solvent (DES), were selected to modify the SS biochar to selectively remove antibiotics from human urine. The modifications of biochar introduced hydrophilic functional groups (-OH/-COOH) on the surface, enhancing selective adsorption of antibiotics. The maximum adsorption capacities of AZ, TMP, TC, SMX, and CPX were 196.08, 370.37, 833.33, 81.30, and 263.16 μg/g, respectively. The regeneration efficiencies of the modified biochar for antibiotics were higher than those for nutrients after five cycles. However, the accumulation of solvents and the possible formation of unidentified byproducts on the biochar surface caused a decline in regeneration efficiency between cycles.

Chlorine, a widely used cleaning agent for toilet cleaners, is commonly detected in source-separated human urine. In the last task, the interference of chlorine during the adsorption of nutrients and antibiotics by SS biochar was studied. There was a significant difference between the adsorption capacities of nutrients and antibiotics with chlorine and without chlorine. The DES-modified SS biochar adsorbed 714 µg/g and 170 µg/g for TMP and 2,500 µg/g and 833 µg/g for CPX for the adsorption processes with and without chlorine, respectively. Based on the adsorption kinetics and isotherm results in combination with EDS, FTIR, and XRD analyses, it was concluded that the presence of chlorine in urine impacts with the adsorption processes by the formation of amines and disinfection by-products. The lower oxidizing ability of chlorine and deprotonation of antibiotics at higher pH explained the lower difference in removal capacity between the adsorption with chlorine and without chlorine.

The sustainable management of nutrients in agricultural systems is crucial for ensuring food security and environmental sustainability. The concept of using biochar to recover nutrients from urine while mitigating the risks associated with antibiotic residues holds great promise. By adsorbing and immobilizing nutrients, while preventing the release of antibiotics, biochar can provide a sustainable pathway for nutrient recycling without compromising environmental and human health. This dissertation research highlights the application of biochar for antibiotic-free nutrient recovery from source-separated human urine as a potential solution for sustainable agriculture, resource conservation, and environmental protection.

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Sayeda Ummeh Masrura
The Force That Sets the Stage: The Professional Performances and Emotional Labor of Black Academic Faculty at Predominantly White Institutionshttps://digitalscholarship.unlv.edu/thesesdissertations/4893https://digitalscholarship.unlv.edu/thesesdissertations/4893Fri, 14 Jun 2024 18:09:06 PDT<![CDATA[

Previous research has examined the racialized experiences of Black/African American faculty at predominantly White colleges and universities through the lenses of critical race theory, identity theory, and emotion management theory. However, these studies have given limited attention to the impact of Whiteness on the lived and emotional experiences of Black faculty in these spaces, as well as the perception and enforcement of professionalism based on White values and norms. This dissertation addresses this gap by conducting thirty-one semi-structured, in-depth interviews with self-identifying Black or African American academic faculty (e.g., adjunct, tenure-track, and tenured professors) currently employed at four-year predominantly White institutions (PWIs) from 2021-2022. It explores Black faculty’s perceptions of professionalism, their choices to conform or resist, and the emotional labor involved by using Erving Goffman's self-presentation strategies and Arlie Hochschild's concepts of emotion management and emotional labor. My dissertation argues that Black academic faculty at PWIs endure a racialized professional performance, including self-presentation and emotional labor strategies to conform or resist White standards of professionalism. It explores how Black faculty navigate these standards while maintaining their Blackness and Black authenticity in a majority-White workplace. My study also explores a range of their negative and positive emotive experiences and examines the factors that contribute to their emotional labor while working at PWIs. My research contributes to the existing knowledge by shedding light on the perpetuation of Whiteness in PWIs and its reinforcement of established norms and standards of professionalism in higher education. By situating their experiences within the norms of the racialized environment, my study provides valuable insights into the challenges faced by Black academic faculty, their sources of empowerment, and offers potential strategies for navigating such environments, thereby contributing to the recruitment and retention of Black faculty in higher education.

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Christian Joy Lewis
Evolution and Natural Selection of Olfactory Receptor Genes in Hawaiian <em>Drosophila</em>https://digitalscholarship.unlv.edu/thesesdissertations/4894https://digitalscholarship.unlv.edu/thesesdissertations/4894Fri, 14 Jun 2024 18:09:06 PDT<![CDATA[

The olfactory system is a powerful tool for sensing countless odorants. In Drosophila, the olfactory system is critical for detecting food, finding mates, laying eggs, avoiding predators, and adapting to new environments. Understanding the olfactory system in Drosophila will advance our knowledge of sensory biology in various insects and vertebrates, including humans. Drosophila has been a valuable model for biology since the early 1900s, and the Drosophila melanogaster olfactory system is well-studied. The Hawaiian Drosophila represent approximately 1/3 of the world’s Drosophila, however, there is limited research on Hawaiian Drosophila olfactory genes. We conducted a comparative analysis of olfactory receptor (OR) genes in four Hawaiian Drosophila and five non-Hawaiian Drosophila species. The four Hawaiian Drosophila (Drosophila silvestris, Drosophila basisetae, Drosophila grimshawi, and Drosophila sproati) were sequenced, assembled, and annotated, while five non-Hawaiian Drosophila species (Drosophila melanogaster, Drosophila simulans, Drosophila yakuba, Drosophila virilis, and Drosophila mojavensis) served as outgroup species. Notably, about 40 out of the 60 OR genes in Drosophila melanogaster were found to be conserved across most Hawaiian Drosophila species. Several genes experienced a high number of positive selection sites, including OR2a, Or46a, OR67a, OR69a, OR71a, OR85f, OR88, and OR92a, which are vital for various functions such as reproduction, oviposition, and detecting food sources and threats. No extreme negative selection was observed among the detected OR genes. There were some differences in OR gene expression between females and males and among different Hawaiian Drosophila species. The changes in OR gene sequences between Hawaiian Drosophila species and differential gene expression indicate that the olfactory system has evolved differences in chemosensory responses between species and sexes. Our study enhances the comprehensive knowledge of sensory biology and the evolutionary patterns of olfactory receptors, providing valuable insights into the distinctive adaptations of Hawaiian Drosophila.

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Ngoc H. Ly
Development of Cultural Familiarity Influences Musical Tempohttps://digitalscholarship.unlv.edu/thesesdissertations/4892https://digitalscholarship.unlv.edu/thesesdissertations/4892Fri, 14 Jun 2024 18:09:05 PDT<![CDATA[

Listeners perceive foreign speech as faster than native speech, even when there is no measurable difference in the speech rate. The mechanisms underlying this “Foreign Language Effect” are currently unknown, but one explanation is that as listeners acquire increasingly language-specific experience, they are able to parse the speech stimulus at increasingly slower levels of language structure (i.e., sentences or phrases rather than just syllables). This ability presumably gives riseto the perception that native speech is slower. Because music also has a hierarchical temporal structure, a similar phenomenon may also exist for tempo perception of culturally familiar and unfamiliar music. To do this, we assessed listeners’ familiarity with each cultural genre from regions (United States, India, Latin America, Turkey, and West Africa) of interests across the globe. Our findings revealed that both tempo and familiarity play a crucial role, as participants tended to perceive less familiar music as faster and familiar music as slower. Overall, this study presents novel evidence that familiarity can alter tempo perception, and interprets how musical familiarity, enculturation, and musical engagement may shape cognitive processes related to tempo perception.

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Jared W. Leslie
Comparison of Male and Female Ultramarathon Runnershttps://digitalscholarship.unlv.edu/thesesdissertations/4890https://digitalscholarship.unlv.edu/thesesdissertations/4890Fri, 14 Jun 2024 18:09:04 PDT<![CDATA[

This research study investigates how specific running variables and demographic characteristics impact performance, or speed, for ultramarathon runners. These variables and characteristics include biological sex, cadence, age range, total distance of the race, duration of the race, years of running experience, total number of ultramarathon races ever completed, and number of races completed in the last twelve months. An ultramarathon is any running distance over a standard marathon or 42.2 kilometers. Participation in ultramarathons has increased by 345% since 2010, with females making up 23% of participants. No in-person data collection was necessary for this study. Participants were asked to export data from their most recent race and complete a survey with questions that included their final race time, pace per mile, and cadence, which were all collected via a personal fitness device. Participants answered questions about their training, how many races they’ve competed in, the number of races in the last year, and race placement. They were also asked about injuries, training, and running strategy. A stepwise regression split by biological sex was completed and found that cadence was a significant predictor of average speed for males, F(1, 17) = 13.065, p =.002, adj R2 = .401, and for females, F(1, 12) = 8.640, p = 0.12, adj R2 = .370. Distance, age range, race time, races ever completed, experience in years, and races in the previous 12 months were not significant predictors of average speed in male and female ultramarathon runners.

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Kelsey Klug
Beyond the Surface: A Novel In-Game Behavioral Observation Matrix to Assess Video Game Expertisehttps://digitalscholarship.unlv.edu/thesesdissertations/4891https://digitalscholarship.unlv.edu/thesesdissertations/4891Fri, 14 Jun 2024 18:09:04 PDT<![CDATA[

In the evolving landscape of gaming, a need for reliable methods to differentiate expertise levels among players has emerged. This study defines experts by their exceptional skills, domain-specific knowledge, and successful application of these attributes in complex situations. Unlike conventional methods that rely on self-reported experience for expertise stratification, this research proposes a shift towards systematic behavioral observation for a more reliable assessment of expertise. The Model of Domain Learning (MDL) facilitates empirical differentiation between novice, competent, and expert categories, allowing for appropriate stratification. Drawing from digital proxemics theory and adapted from the behavioral assessment matrix used by McCreery and team (2011), this research is situated in observable behaviors in digital environments within the constructs of spatial positioning, spatial realization, spatial appropriation, and spatial interactivity as pivotal facets of expertise.

The innovative Behavioral Observation Matrix-Proxemics (BOM-Proxemics) was developed to systematically code indicators of expertise expressed via observable in-game behaviors. Through iterative expert review, the BOM-Proxemics underwent development and judgment-qualification stages to identify 16 observable in-game behaviors. The BOM-Proxemics demonstrated high inter-observer agreement and moderate to high internal consistency. Concurrent validity was established with a moderate positive correlation between the BOM-Proxemics scores and in-game ranks. Subsequently, a proportional-odds ordinal logistic regression was conducted to predict in-game rank using BOM-Proxemics scores. The results indicated that the BOM-Proxemics was a significant positive predictor of in-game rank, suggesting that higher scores on the instrument were associated with increased odds of achieving a higher rank in the game. The magnitude of this effect size was substantial, emphasizing the practical significance of the findings and reaffirming its efficacy in assessing expertise.

Proportional-odds ordinal logistic regression analysis was conducted for each subscale, revealing that the Spatial Positioning, Spatial Appropriation, and Spatial Interactivity subscales emerged as significant predictors of in-game rank, while Spatial Realization did not. These outcomes underscore the differential impact of proxemics domains on expertise categorization, offering insights into the specific behavioral dimensions that hold significance in assessing video game proficiency. By employing an one-way analysis of variance (ANOVA), the investigation uncovered substantial between-group differences based on in-game rank (novice, competent, expert). Notably, a significant variation in BOM-Proxemics scores was observed among these groups, with pairwise comparisons indicating significant differences in mean scores across all three expertise categories. This evidence highlights the discriminatory potential of the BOM-Proxemics in effectively differentiating expertise levels.

These outcomes demonstrate the BOM-Proxemics' validity, predictive power, and the varying impacts of different subscales, contributing to its robustness as a tool for evaluating game expertise based on observable behaviors. Further, the results offer insights that could inform the development of effective strategies for skill enhancement and training within the gaming community. The results of this study underscore the value of objective behavioral observation in quantifying gaming expertise and contribute to the discourse surrounding skill measurement within dynamic virtual environments.

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Sam A. Leif
Beyond Corporate Greenwashing: Discourse of a 'Just' Electric Energy Transition Materialized at the Thacker Pass Lithium Minehttps://digitalscholarship.unlv.edu/thesesdissertations/4888https://digitalscholarship.unlv.edu/thesesdissertations/4888Fri, 14 Jun 2024 18:09:03 PDT<![CDATA[

Thacker Pass in Northern Nevada is a rich desert ecosystem with spiritual significance to local Indigenous peoples, and it is also the site for what will be, for now, the United States’ largest open-pit lithium mine. Lithium is one mineral constituent of electric batteries which are essential to current U.S. electric energy transition policy, a transition which policymakers and other public groups have called on to be done in a way which is just. However, what exactly a just electric energy transition looks like in places like Thacker Pass is under continued negotiation in theoretical and practical senses. Existing research has provided theoretical lenses to interpret the intersection of corporate messaging, mining and extractive industries, critiques of domination, and mapping participants in discourses. To contribute to an understanding of how a just electric energy transition is characterized at Thacker Pass, and values dominating the discourse there, the present study evaluated electric energy transition discourse around the Thacker Pass lithium mine through a textual analysis of public-facing documents from both industry and resistant groups. The analysis finds that the lithium mining company justifies extraction as part of a just energy transition, characterizing themselves as valors of climate crisis and mitigating the appearance of traditional mining harms. Meanwhile, resistant stakeholders interrupt popular notions of a just energy transition, redefining terms like green and clean in the context of mining and calling on concepts of justice to call attention to the unjust nature of mining at Thacker Pass. Ultimately industry characterizations align with popular neoliberal approaches to climate change mitigation policy that continue to prioritize production and consumption, marginalizing ideologically paradoxical value priorities such as land protection, reduced consumption, and distributing more negotiating power to Tribes. Theoretically, this study contributes to expanding the subfield of energy communication studies toward the newer context of mining for the electric energy transition. It also offers critical theories, and frameworks such as the stakeholder model to begin the process of uncovering motivations in this new energy context taking place within familiar political and economic power structures. More practically, this study contributes to informing an electric energy transition which is just by calling attention to the material spaces where the transition is manifesting, especially new mining sites.

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Laekyn Kelley
Improving Multi-Crane Planning on Construction Siteshttps://digitalscholarship.unlv.edu/thesesdissertations/4889https://digitalscholarship.unlv.edu/thesesdissertations/4889Fri, 14 Jun 2024 18:09:03 PDT<![CDATA[

Designing the configuration of tower cranes, managing their operations, and coordinating material logistics are intricate processes that wield significant influence over the time, cost, productivity, and safety of construction projects. This complexity stems from the multitude of layout configurations, diverse crane types, varied tasks, and material supply points, all interacting within a dynamic environment. Collisions pose a heightened risk due to overlapping crane areas, further adding complexity to the planning of crane layouts and operations. Optimizing crane layout and operational planning while ensuring safety requires establishing effective connections between tasks, cranes, and material supply locations. Traditionally, research and industry practices have focused on linking tasks to supply points with the shortest individual task operating times, minimizing the completion time for each task. However, this approach may not be the most efficient for larger construction sites with multiple overlapping crane areas, where minimized individual task times do not guarantee an effective planning. To tackle this challenge, this dissertation introduces agent-based models to explore diverse scenarios for crane layout planning, operational planning, and material management. Three objectives are set to enhance the efficiency of crane layout, operational planning, and material management, which collectively seek optimal solutions. These models underwent testing on construction projects as case studies, and the results underscore the significant improvements achievable through effective linkage of tasks to cranes and supply points, both in terms of efficiency and the overall construction project schedule.

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Ali Khodabandelu
Healthcare Practices in the United States Aimed at Improving Care and Language Access Services for Limited English Proficiency Refugees: A Systematic Reviewhttps://digitalscholarship.unlv.edu/thesesdissertations/4887https://digitalscholarship.unlv.edu/thesesdissertations/4887Fri, 14 Jun 2024 18:09:02 PDT<![CDATA[

Objective: The United States has accepted over 3 million refugees from all around the world since 1975. However, many Limited English Proficiency (LEP) refugees face significant barriers when seeking healthcare due to limited access, lack of knowledge, mistrust in physicians, language differences, cultural concerns, and overall complexity of the U.S. healthcare system. The purpose of this systematic review was to identify practices in the last 10 years that have improved healthcare and language access services for LEP refugees living in the U.S.

Methods: A search was conducted in four electronic databases PubMed, Embase, CINAHL, and Scopus from January 2013 to May 2023. Studies were included if they were 1) focusing on practices or interventions 2) aimed at improving healthcare and language access services 3) for limited English-speaking refugees. Studies were excluded if published in countries outside the U.S.

Results: The initial search yielded 1649 articles. After review, 12 articles met the inclusion criteria; these articles consisted of interventions, language access practice guidelines, and quality improvement. The results of the literature found that successful interventions involved cultural brokers and qualified medical interpreters in the design and development of interventions for refugee target groups, as well as the relevance of timely and comprehensive training for providers regarding the treatment of LEP refugee populations.

Conclusion: Implications for future research include the identification of alternative methods to engage cultural brokers, recruitment of qualified medical interpreters, and training medical providers while partnering with local refugee communities. Future research should focus on identifying best practices for building long-term partnerships between medical providers and refugee communities. In conclusion, this literature review contributes to the overall knowledge of the patient-provider relationship for LEP refugee population in the U.S.

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Bemnet Kebede
Emergency Remote Teaching and Transition to Nursing Practice During the Covid-19 Pandemic: An Interpretative Phenomenological Analysishttps://digitalscholarship.unlv.edu/thesesdissertations/4885https://digitalscholarship.unlv.edu/thesesdissertations/4885Fri, 14 Jun 2024 18:09:01 PDT<![CDATA[

Purpose: The purpose of this phenomenological study was to explore the lived experience of new nurses in the United States who experienced Emergency Remote Teaching (ERT) for most or all of their nursing education during the COVID-19 pandemic and how they perceive ERT influenced their transition to practice during their first year as registered nurses.

Background: The National Council of State Boards of Nursing reports that in 2021, the overall pass rate for first-time NCLEX-RN® demonstrated the sharpest decline since 2013. Most of the 185,000 nursing students who took the exam in 2021 and 2022 received their nursing education during the COVID-19 pandemic, experiencing a rapid transition to remote learning, which involved drastic limits to clinical experiences, simulation education, psychomotor-skills labs, and didactic course delivery. Prelicensure nursing students who experienced pandemic-related disruption to their education are now registered nurses and have transitioned to practice. Exploration of how nurses make sense of their experiences with ERT and the significance of these experiences on their transition to the nursing role is essential to understanding the implications of disrupted learning on the transition to nursing practice.

Methods: A multi-philosophical perspective rooted in the philosophies of phenomenology, hermeneutics, and ideography was used as an underpinning for this qualitative study. Guided by the Interpretative Phenomenological Analysis (IPA) process, the exploration of the lived experiences of 12 nurses living across the U.S. who transitioned to RN practice after experiencing ERT due to the pandemic was conducted through individual semi-structured interviews that were video recorded and transcribed. Data analysis guided by the seven steps of IPA revealed Personal Experiential Themes in individual cases and Group Experiential Themes across all 12 cases. Themes were individually identified and then clustered based on common meanings to understand how the participants perceived and made sense of their experience.

Results: Findings revealed three superordinate themes, each with three subthemes, that give meaning to the participants' experiences as a student, then transitioning to practice, and their current life-world establishing themselves as nurses. The first central theme, Awareness of Being Foundationless, includes the subthemes of an Era of Uncertainty, the Disruption of Dynamic Learning, and the Loss of Embodied Experiences. The second theme, the Challenge of Becoming, encompasses the subthemes of Struggling with Irreconcilable Expectations, the Guiding Presence of a Preceptor, and the Perpetual Cycle of Systemic Dysfunction. The third theme, the Evolving Nursing Role, includes the subthemes of Personal Toll of Being a Nurse, Strength Through Adversity, and Dedication and Detachment in the nursing role.

Implications: Current literature describes nursing students' perceptions of ERT during the pandemic; however, no published research explores the phenomenon of the transition to nursing practice for those who experienced these pedagogical changes and how it continues to affect their practice. The timely opportunity to explore this phenomenon in-depth allowed nurses to reflect on their experiences with ERT in nursing school and share their perspectives on how ERT has shaped their first year of nursing practice. Results may help educators and administrators shape contingency teaching plans for potential future pandemics and explore innovative ways to preserve the practical nature of critical educational experiences that may not be appropriately replaced by ERT. Study results amplify the need for supporting these new nurses in their socialization to the nursing role and throughout their careers.

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Carrie Watkins Jeffrey
Toolstone Use and Procurement Along Holocene Ivanpah Dry Lake, CAhttps://digitalscholarship.unlv.edu/thesesdissertations/4886https://digitalscholarship.unlv.edu/thesesdissertations/4886Fri, 14 Jun 2024 18:09:01 PDT<![CDATA[

Ivanpah Dry Lake is a Holocene dry lake located in the Mojave Desert along the California-Nevada border along I-15. Ivanpah Dry Lake is well studied in small parcel segments through gray literature but has had little work done in the accessible realm of academic literature. The aim of this thesis is to create a synthetic document regarding the archaeology of Ivanpah Dry Lake, focusing on toolstone use and procurement strategies employed by those who lived along the shores and on the playa of this lake. Recent research by Spaulding and Sims (2018) has revealed two new Holocene lakestands at Ivanpah Dry Lake as well as one additional Terminal Pleistocene/ Early Holocene lakestand, contrary to the existing notion of lake desiccation around 9,000 years ago. Reexamination of past Cultural Resource Management (CRM) reports and synthesis of existing site records has revealed how these new lakestands and subsequent lacustrine environments may have impacted mobility and subsistence strategies of those who occupied or passed through the area. These factors can be investigated through lithic procurement strategies including factors of material choice and the use of differing tool technologies in response to a changing climate. GIS is employed to examine how site distributions may have changed during these varying lake level periods. Additionally, this research argues that the entirety of the Ivanpah Dry Lake (IDL) area is culturally sensitive and warrants protection from further invasive development.

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Kara Jones
Virus Removal and Characterization During Secondary Treatment at a Full-Scale Planthttps://digitalscholarship.unlv.edu/thesesdissertations/4883https://digitalscholarship.unlv.edu/thesesdissertations/4883Fri, 14 Jun 2024 18:09:00 PDT<![CDATA[

Virus removal is paramount to water reuse applications and nearly all water reuse applications require extensive pathogen reduction because of high influent concentration, difficulty of detection and distinguishing infectivity. Typically, regulations stipulate virus attenuation that require the implementation of multi-barrier advanced treatment trains and award these reductions in log notation called log reduction values (LRVs). Reduction of virus concentrations are not awarded for virus removal that may occur in wastewater treatment steps which precede water reuse units such as activated sludge secondary biological treatment.

A systematic literature review was performed and virus reduction at full-scale wastewater treatment plan was monitored to gain a better understanding of the mechanisms of virus attenuation during secondary biological treatment of activated sludge. The literature review was conducted according to the PRISMA guidelines with a uniform search method through Scopus, PubMed and Web of Science databases. The full-scale plant monitoring consisted of a 12-week composite sampling event, 3-week aeration basin grab sampling event and a follow-up grab sample event in the same aeration basin to determine virus partitioning. Viruses were quantified by both culture methods and through qPCR during each sampling event and wastewater quality parameters were provided by the plant operators.

The literature review found mostly weak correlation between removal efficiencies and the existing literature did not support the recommendation of awarding virus concentration reduction credits to activated sludge secondary treatment. CrAssphage, f-specific coliphages and somatic coliphages all had the highest reported LRVs during secondary treatment at the full-scale plant of 2.5-log reduction. The lowest LRVs reported were 0.6-log for pepper mild mottle virus (PMMoV) and Cucumber Green mottle mosaic virus (CG). The variability in virus reduction during the secondary treatment was mostly due to virus quantification methodology and there was less desorption of viruses from solids due to the addition of Tween 80 surfactant as aeration progressed.

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Tyler Hill
Evaluation of Corrosion Resistance of Reinforcing Bar Types for Pavements and Bridgeshttps://digitalscholarship.unlv.edu/thesesdissertations/4884https://digitalscholarship.unlv.edu/thesesdissertations/4884Fri, 14 Jun 2024 18:09:00 PDT<![CDATA[

This study aimed to evaluate the corrosion resistance of six distinct reinforcing bar types; namely, the bare, epoxy coated steel, quenched and tempered steel, ChromX 9100, Duplex 2304 stainless steel, and galvanized steel in “as-rolled” condition using the ASTM A955 Cracked Beam and Rapid Macrocell tests, and ASTM G109 test. The results were used to compare the corrosion rate and corrosion loss of various reinforcing bar types against those obtained for the bare reinforcing bars. This study also sought to identify an alternative reinforcing bar type to the epoxy coated reinforcing bars which are overwhelmingly specified by the US Departments of Transportation.

The Rapid Macrocell test was conducted for fifteen weeks as prescribed by ASTM A955. Accordingly, the overall average corrosion rate of the Duplex 2304 stainless steel, epoxy coated, galvanized, ChromX, and quenched and tempered reinforcing bars was 0.25%, 25%, 33%, 50%, and 150%, respectively, of that of the bare reinforcing bars. The corresponding overall average corrosion loss of the above-mentioned reinforcing bars was 0.22%, 25%, 33%, 40%, and 125% of that of the bare reinforcing bars.

While the ASTM A955 Cracked Beam test required a maximum of ninety-six weeks of testing, only forty-eight weeks of data was presented since the weekly average corrosion rate for each reinforcing bar type stabilized after thirty-two weeks of testing. By week forty-eight, the overall average corrosion rate of the Duplex 2304 stainless steel, epoxy coated, galvanized, ChromX, and quenched and tempered reinforcing bars was 0.5%, 1%, 20%, 80%, and 150%, respectively, of that of the bare reinforcing bars. The overall average corrosion loss of the Duplex 2304 stainless steel, epoxy coated, galvanized, ChromX, and quenched and tempered reinforcing bars was 44%, 0.67%, 25%, 70%, and 150%, respectively, of that of the bare reinforcing bars.

Overall, the Duplex 2304 stainless steel reinforcing bars performed the best against chloride-induced corrosion followed by the epoxy coated, galvanized, ChromX, bare, and quenched and tempered reinforcing bars in both the Rapid Macrocell and Cracked Beam tests. The results of the ASTM G109 test were not presented since there were insufficient data to date, and the test is still ongoing.

Based on the comparison of the combined cost and performance of the studied reinforcing bar types under the controlled laboratory conditions, the galvanized reinforcing bars were recommended as an alternative to the epoxy coated reinforcing bars.

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Brandon T. Huynh
The Room Temperature Electrolysis of F-Elements in Aqueous and Ionic Liquid Media: Synthesis, Dissolution, and Reductionhttps://digitalscholarship.unlv.edu/thesesdissertations/4882https://digitalscholarship.unlv.edu/thesesdissertations/4882Fri, 14 Jun 2024 18:08:59 PDT<![CDATA[

Procuring F-element metals is no simple task and often requires the use of caustic and hazardous materials at high temperatures. These materials are invaluable for a variety of scientific missions ranging from the elucidation of fundamental properties, as fast spectrum nuclear fuel forms, to pit production modernizing our nuclear stockpiles. Metallic actinide materials are essential to strategic and critical materials recovery, the nuclear energy sector, and weapons production. Room temperature electrolysis is envisioned as a process to recover laboratory scale (milligram to gram) quantities of actinide metals. This process closes the uranium chemical loop allowing the reclamation of materials for continued laboratory use. Ionic liquids (IL) at ambient temperature are used to electrochemically reduce and deposit uranium as a gateway element to other actinides. Reactions designed to enhance the solubility of uranium in the IL produce several species including truly anhydrous U(TFSI)3•3THF, UO2(TFSI)2•3THF and a second reporting of hexavalent UO2I4-2 anion found for the first time coordinated to the IL cation. These compounds are evidenced by UV/vis and RAMAN spectroscopy, TGA – DSC, SCXRD and EXAFS analyses.

Uranium metal electrodes are characterized and used for the electro-reduction of uranium IL species. Controlled potential electrolysis and differential pulsed amperometry are investigated as electrolytic techniques for metal deposition. Variation in potential pulse frequency show changes in the nature of the collected deposits. Extended periods of electrolysis are required to collect milligram amounts of material and define solid electrode deposition as a low throughput method. High potential applications to radioactive materials exemplify the robustness of the IL as a stable radiolytic and electrochemical medium suitable for modified separations processes. The obtained deposits are finely divided and loosely fixed to the electrode surface which react quickly and complicate metal phase determination.

Efforts were extended to establish an electrochemical amalgamation and thermal vacuum mercury extraction system within an inert atmosphere environment. The custom glovebox, contains both an electro-amalgamation station and a high temperature vacuum furnace. The electro-amalgamation system is tested with aqueous pH buffered and non-aqueous (IL) media. Proof of principle is verified through the recovery of gold and cerium amalgams. Alterations to the furnace vacuum level and temperature ramp rate have enabled metal recovery without losses to distillational sputtering. Thermal extraction has recovered milligram amounts of both metal-mercury condensate and purified metals.

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Phillip George Hammer
Investigating a Passive Treatment System for the Removal of Nutrients from Urban Runoffhttps://digitalscholarship.unlv.edu/thesesdissertations/4880https://digitalscholarship.unlv.edu/thesesdissertations/4880Fri, 14 Jun 2024 18:08:58 PDT<![CDATA[

The Environmental Protection Agency recognizes urban runoff as a major contributor of surface water pollution with nutrients as the second largest cause of surface water impairment in the United States. While a water quality standard of 100 lbs/day total phosphorus load allocation for all nonpoint sources is permitted for the Las Vegas Valley (LVV) under the National Pollutant Discharge Elimination System, currently there is not a counterpart standard for nitrogen. With the continued development of the LVV and the depletion of the quantity of water in Lake Mead due to the ongoing drought, the concentrations of phosphorus and nitrogen species within Lake Mead are expected to increase. As such, future revisions to regulations may call for the treatment of stormwater and urban runoff in order to reduce nitrogen and phosphorus pollutant loads. Therefore, there exists a need to explore treatment technologies for the removal of theses nutrients from LVV urban runoff. Furthermore, as urban runoff volumes can be quite large, it is important to explore technologies that are passive and do not require pumping or mixing. The objective of this research was to investigate the removal of nitrate (NO3), ammonia (NH3), and phosphate (PO4) from a synthetic stormwater solution using zero-valent iron (ZVI) and zeolite. The effectiveness of nitrate reduction and phosphate precipitation by ZVI, and the removal of ammonia by zeolite via ion-exchange was evaluated in this study. Continuous flow, laboratory-scale column experiments were the selected methodology with four different column designs featuring layered or mixed media configurations. The removal of NO3 was influenced less by the amount of ZVI used in the columns and more by the hydraulic retention time (HRT), with NO3 removal of 54-97% observed for an average HRT of at least 7 hours. The removal of NH3 depended less on HRT and more on the amount of zeolite used in the columns with >80% ammonia removal observed when the amount of zeolite used was increased by 6-7 times. High phosphate removals ranging between 80-100% were consistently observed regardless of HRT or amount of ZVI used. Overall, layered media configurations within the columns achieved higher percent ranges in nutrient removal, with ZVI layered above zeolite ensuring that the ammonia produced by the reduction of nitrate by ZVI in the top layer was then captured in the zeolite bottom layer for removal by ion exchange. All in all, a dual media zeolite and ZVI passive treatment system for the removal of nutrients from urban runoff is feasible and partial removal of ammonia and nitrate with near complete removal of phosphate is expected.

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Jasminn Gray
Investigating van der Waals Josephson Junctions with 2H-NbSe<sub>2</sub> and 1T’-Wte<sub>2</sub>https://digitalscholarship.unlv.edu/thesesdissertations/4881https://digitalscholarship.unlv.edu/thesesdissertations/4881Fri, 14 Jun 2024 18:08:58 PDT<![CDATA[

Josephson junctions have garnered significant attention due to their unique electronic properties and applications in quantum devices. In this thesis, we investigate the fabrication processes and characterization of two-dimensional (2D) Josephson junctions consisting of layered van der Waals materials: niobium diselenide (2H-NbSe2) and few layered tungsten ditelluride (1T’-WTe2). The reduction of dimensionality can bring forth unique characteristics in certain materials that are not seen in their bulk counterparts, making them prime candidates for physical exploration. 2H-NbSe2 is an s-wave superconductor at temperatures near and below 7 K. 1T’-WTe2 is a semimetal in bulk but is an intrinsic quantum spin Hall insulator in monolayer form, with a large (55 meV) band gap. Both materials exhibit exotic behavior, and the coupling of the two provides the necessary environment for entangled quasiparticles known as Majorana zero modes (MZMs). In a topologically protected environment, MZMs could be used to encode quantum information, addressing one of the leading obstacles of decoherence in current solid-state qubits. In our investigation of Josephson junctions with 2H-NbSe2 and few layer 1T’-WTe2, disorder became a prevalent issue, hindering expected electronic transport properties of the Josephson effect. The devices studied in this thesis exhibit transparent and non-transparent Andreev reflections. This comparison sheds light on the distinct behaviors of highly disordered and low-disordered interfaces and their implications for quantum effects.

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Kristine Lorraine Haley
An Evaluation of Lead Concentration in Commercially Available Tileshttps://digitalscholarship.unlv.edu/thesesdissertations/4878https://digitalscholarship.unlv.edu/thesesdissertations/4878Fri, 14 Jun 2024 18:08:57 PDT<![CDATA[

Workers in the manufacturing and construction industries are at risk of lead exposure in projects that involve removal or installation of tiles, and other individuals exposed to lead, including children may also be at risk. The concern with lead in tiles is thought to be related to the glazing process or the country where the tile was produced. Multiple regulations are in place in the U.S. to protect people from lead exposure, including through surface coatings or painted surfaces. But these regulations do not cover glazed tiles. This study examined whether there are differences in lead concentration in (1) tiles from foreign countries compared to the U.S. and (2) glazed tile finishes compared to unglazed finishes using the 200 best-selling tiles from two major home improvement stores and tile specialty stores. A total of 191 tiles were examined to determine their lead concentrations for XRF readings, 16 tiles were examined for dust hazards, and 45 tiles were examined for debris lead concentrations. The study relied on three different methods to test for lead: (1) initial screening utilizing the X-Ray Fluorescence (XRF), (2) lead dust sampling of intact tiles, and (3) sampling lead concentration in the demolished tiles. The results from the XRF readings among countries did not differ. The concentration of lead in the dust samples showed that tiles manufactured in South and Central America (n=6) contained higher concentrations of lead (10+ mg/cm2) than those manufactured in Europe (n=1) and Asia (n=0), but not higher than those manufactured in the U.S. (n=3). Of the 191 dust samples collected 10/191(5.2%) exceeded the Environmental Protection Agency’s (EPA) Dust-Lead Clearance Levels (DLCL) of 10 mg/cm2. The concentrations of lead in the debris samples showed that tiles manufactured in Asia (n=8) and Europe (n=0) were statistically significant, but there were no significant differences among Central and South America (n=1) or the U.S. (n=6). The results from the XRF showed that glazed tiles compared to those that were unglazed were not significantly different (p=0.454). Analysis of the dust samples for glazed and unglazed tiles did not differ (p=0.234). Similarly, the debris samples for glazed and unglazed tiles did not differ (p=0.611). The study found that 5.2% of dust samples exceeded the DLCL standards of 10 mg/ft2, straight from the packaging. This was concerning if a HUD home inspection would have been conducted for presence of lead-based paint hazards, the clearance would have failed, deeming the home unsafe for the occupants to return as well as for entry by unprotected workers. It is imperative that the EPA’s dust-lead hazard standards be implemented for tiles. It is also imperative to amend the EPA’s Renovation, Repair, and Painting Program and the Consumer Product Safety Commission to also include tiles to prevent further exposure of lead.

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Daidre N. Gamboa
Interaction of Technetium (IV) with Dibutyl Phosphate in n-Dodecanehttps://digitalscholarship.unlv.edu/thesesdissertations/4879https://digitalscholarship.unlv.edu/thesesdissertations/4879Fri, 14 Jun 2024 18:08:57 PDT<![CDATA[

During the reprocessing of nuclear fuel, the degradation of tributylphosphate (TBP) occurs as a result of radiolytic and thermal processes. These processes lead to the formation of minor amounts of dibutyl phosphate (HDBP). However, the presence of DBP poses a challenge in the partitioning of uranium (U), plutonium (Pu), and technetium (Tc) due to its chelating effects. The chelation of these elements by HDBP can interfere with their intended separation and purification, thereby impacting the efficiency and effectiveness of the reprocessing process. In this study, X-ray Absorption Fine Structure (XAFS) spectroscopy is employed to investigate the speciation of Tc following the extraction of Tc(IV) from both water (H2O) and 1M nitric acid (HNO3) using dibutyl phosphate (HDBP) in dodecane as the extracting system. The XAFS results revealed the formation of polymeric species containing Tc2O2 and Tc2O units. Specifically, the species extracted from H2O was proposed to have the formula [Tc2O2(DBP·HDBP)4] (1), while the species extracted from 1M HNO3 was proposed to have the formula [Tc2O(NO3)2(DBP)2(DBP·HDBP)2] (2). The interatomic Tc-Tc distances in the Tc2O2 and Tc2O units were found to be approximately 2.55(3) Å and 3.57(4) Å, respectively, resembling the distances observed in Tc(IV) dinuclear species. These findings suggest that the speciation of Tc(IV) in a HDBP/dodecane mixture involves the extraction of a species with a Tc2O unit in the case of (2), while the species observed in (1) may be attributed to the re-dissolution of a Tc(IV)-DBP solid. The reduction kinetics of Tc(VII) with hydrazine were monitored through UV-Vis spectroscopy. Respective concentrations in the aqueous and organic each phase was calculated using liquid scintillation counting.

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Jonathan George
Scalable Algorithm Design and Performance Analysis for Graph Motifs Discoveryhttps://digitalscholarship.unlv.edu/thesesdissertations/4877https://digitalscholarship.unlv.edu/thesesdissertations/4877Fri, 14 Jun 2024 18:08:56 PDT<![CDATA[

Discovering motifs or structural patterns, such as communities, is a significant graph application utilized for classifying groups in social and business networks, identifying similar proteins, detecting anomalous behavior in the cybersecurity domain, and finding critical entities in rumor propagation or infectious disease spreading. Existing state-of-the-art techniques for community discovery face challenges related to scalability, performance limitations, and methodological inaccuracies. The objective of this doctoral dissertation is to introduce novel parallel algorithms and propose high-performance computing architecture designs to address the performance constraints of current community detection approaches when processing large-scale social and biological data. This research focuses on two main categories of community discovery problems: i) global community discovery and ii) local community discovery. We identify two notable sequential approaches, one from each category, and develop and implement parallel algorithm solutions for both. Our parallel algorithm design for global community discovery achieves a substantial speedup of up to 25x compared to the original sequential approach, leveraging hybrid memory parallelism. Furthermore, we conduct comprehensive benchmarking and performance analysis of software hash accumulation on two prominent community discovery approaches. Based on our findings, we propose a generalized accelerator design for hash accumulation and simulate the proposed architecture, achieving up to a 5.6x speedup. For the local/goal-oriented community discovery approach, we design an innovative parallel algorithm based on shared memory parallelism, demonstrating a remarkable speedup ranging from 20x to 55x for massive graphs with millions of vertices and billions of edges.

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Md Abdul Motaleb Faysal
Examining Emotion Regulation Strategies as Predictors of Posttraumatic and Depressive Symptomatology in Maltreated Youthhttps://digitalscholarship.unlv.edu/thesesdissertations/4875https://digitalscholarship.unlv.edu/thesesdissertations/4875Fri, 14 Jun 2024 18:08:55 PDT<![CDATA[

Youth with a history of maltreatment victimization are at heightened risk for developing symptoms of posttraumatic stress and depression. Recent work has identified emotion dysregulation as a potential transdiagnostic mechanism linking maltreatment victimization to youth psychopathology, but few studies have examined the influence of specific emotion regulation strategies. Habitual utilization of expressive suppression and cognitive reappraisal have each demonstrated associations with trauma-related psychopathology in adults. The present study examined both strategies as predictors of posttraumatic and depressive symptomatology in youth with a history of maltreatment, as well as mediators in the relationship between the two conditions.

The sample included 133 youth aged 11–17 years in Department of Family Services (DFS) custody following removal from their home after a child maltreatment report. Multiple regression analyses revealed significant, positive relationships between expressive suppression and total depression symptoms, total PTSD symptoms, and symptoms of each PTSD symptom cluster. Cognitive reappraisal was positively related to total PTSD symptoms, intrusion symptoms, and alterations in cognitions and mood, and was not associated with symptoms of depression, avoidance symptoms, or alterations in arousal and reactivity. SEM-oriented mediation analyses did not implicate either strategy as a mediator of the relationship between PTSD and depression. The findings offer important implications for assessment, intervention, and future emotion regulation research.

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Kinsey Ellis
Examining COVID-19 Vaccine Hesitancy Among The Nevada African American Population Using the Social-Ecological Modelhttps://digitalscholarship.unlv.edu/thesesdissertations/4876https://digitalscholarship.unlv.edu/thesesdissertations/4876Fri, 14 Jun 2024 18:08:55 PDT<![CDATA[

In Nevada, COVID-19 vaccines have been widely available to the general population since March 2021; however, even with the wide availability of these vaccines only 40% of the African American population in Nevada has been fully vaccinated against COVID-19 as of May 2023. This is problematic as it has been shown that the African American population is disproportionately affected by COVID-19 with higher rates of cases, hospitalizations, and deaths when compared to other races or ethnicities. Through the literature, it has also been well documented that African Americans may experience hesitancy toward these vaccinations for a multitude of reasons including mistrust of the healthcare system, mistrust of the government, and safety and efficacy concerns. The purpose of this quantitative cross-sectional study was to use the social-ecological model to examine how these known factors related to African American vaccine hesitancy at the intrapersonal, interpersonal, and community levels. This study utilized data collected from a previous telephone survey conducted in December 2020 before the COVID-19 vaccines were widely available and before the COVID-19 strains of Delta and Omicron to examine vaccine hesitancy among the African American population in Nevada. The results from this study were analyzed using binary logistic regression analysis. A feeling of worry regarding COVID-19 and a study participant’s age had a significant association with the intent to receive the COVID-19 vaccine. The age group 65 and up had the highest intent and the age group 34-44 had the lowest intent to be vaccinated. A significance value of p < 0.05 and 95% confidence intervals were used to test the associations at the three levels of the social-ecological model. Results from this study may be used by public health officials to create tailored interventions to increase COVID-19 vaccination rates among African Americans in Nevada.

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Katelyn Faulk
Travel Time Theory For Traffic Conservation Laws With Applicationshttps://digitalscholarship.unlv.edu/thesesdissertations/4873https://digitalscholarship.unlv.edu/thesesdissertations/4873Fri, 14 Jun 2024 18:08:54 PDT<![CDATA[

Travel time is an important concept in various intelligent transportation system (ITS) applications. The concept is used in a wide array of applications, such as system planning, system performance, and optimization. Reducing the time required to travel between different points on a network is an important goal. Benefits include reducing time wasted in traveling, and keeping travelers satisfied. Thus, studying and reducing travel time in ITS is beneficial in different applications.

The classic density-based Lighthill Whitman Richards (LWR) equation for modeling traffic flow is the starting point in this dissertation. A more recent travel time dynamics function built on top of the classic equations is reviewed. The travel time dynamics are an asymmetric, one-sided coupled system of hyperbolic partial differential equations (PDEs).

One main contribution of this dissertation is the mathematical development of the method for finding the viscosity solution of the given travel time PDE. Additionally, the viscosity solution is directly related to the entropy solution of the density based LWR equations. This relation is used as evidence in using the travel time dynamics for numerical applications.

Another contribution is expanding the widely applied numerical method for simulating the LWR equations to include travel time analysis. The standard method to evolve LWR dynamics is with the Godunov scheme. The numerical technique is expanded to include dynamic travel time. Nodes for network studies are presented and minimizing travel time is used as a control decision for splitting flow in nodes of a network.

Finally, after introducing the travel time dynamics for the Godunov scheme, some examples of applications using travel time analysis are presented. These examples include bidirectional splitting which can be used for pedestrian modeling, network bidirectional splitting, and bottleneck incidents. These examples are then used as building blocks to simulate a more complex network.

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Sergio Contreras
Examining the Social Equity Pillar of Sustainability: The Effects of Public Participation and State Actions on Local Social Services Initiativeshttps://digitalscholarship.unlv.edu/thesesdissertations/4874https://digitalscholarship.unlv.edu/thesesdissertations/4874Fri, 14 Jun 2024 18:08:54 PDT<![CDATA[

Sustainability policies are vital in promoting social equity in municipalities across the United States. When examining economic development, environment protection, and social equity, the three pillars of sustainability, the third pillar of social equity is shown in research to be largely ignored. Using understanding drawn from co-production theory and the multilevel governance perspective, this study proposed to advance the literature on urban sustainability by examining the effects of public participation and state grants of local authority on municipal social equity. Affordable housing, transportation, and childcare programs are essential in promoting livability and social equity within urban communities. National survey data from the 2015 Local Government Sustainability Practices Survey was used to build logit regression models. These models were then used to test whether increased public participation and state influence through fiscal and technical support would influence the advancement and implementation of sustainability policies that support affordable housing, transportation, and childcare programs. This study proposed that the greater the public participation and state influence, the more likely sustainability policies promoting social equity would be advanced and was supported by the findings.

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Jennifer Mary Crownhart
Addressing Challenges Faced by Public Organizations: The Central Role of Agility at the Federal Level During the Covid-19 Crisishttps://digitalscholarship.unlv.edu/thesesdissertations/4871https://digitalscholarship.unlv.edu/thesesdissertations/4871Fri, 14 Jun 2024 18:08:53 PDT<![CDATA[

This dissertation investigates the role of organizational agility in public organizations (such as the United States Federal Agencies) and demonstrates how agility works in public institutions. This study explores how organizational agility within public institutions can lead to successes and prevent failures stemming from underutilized agility, identifies the societal demographics impacted by these outcomes, and offers recommendations for effectively implementing agility to enhance efficiency and societal progress. Agility in sum, is adaptability and proactiveness. If developed and practiced by public organizations, this process can avert prominent institutional failings that impede the dispersal of services and resources that would promote social progress. Public organizations often cope with multiple objectives, an evolving economic and political environment, and an unwieldy bureaucratic structure that impedes progress as they attempt to fulfill the desires of many stakeholders. Currently, national and state institutions are regularly criticized for underperforming and failing to meet the challenges they are meant to address. The disastrous implementation of public policy healthcare and educational initiatives in terms of the COVID-19 disaster is one prominent example. Influenced by information technology (IT) infrastructure capability, agility, when correctly applied, can improve public organizational performance and avert these types of failures.

A review of existing works in public affairs reveals a limited understanding of organizational agility, and it can be argued that, due to the salience of agility, this is a shortcoming in the literature. To develop recommendations, this work addresses this gap by developing a theoretical conception of how agility develops in public organizations and demonstrates why it is critical to develop this understanding. It also presents hypotheses demonstrating agility's academic and practical implications when adequately implemented and tested using data collected by the Federal Employee Viewpoint Survey (FEVS). Specifically, the research hypothesizes that agility is influenced by organizational justice, which in turn is influenced by servant leadership in public organizations. Data analysis used the Partial Least Squares (PLS) approach to Structural Equation Modeling (SEM). Analyses show that the hypotheses are generally supported. The research shows that agile organizations are more likely to achieve better organizational performance and that organizational leadership and justice are essential in developing agility. This research is primarily dedicated to developing and validating a theoretical framework that captures organizational agility for public organizations. From a practical standpoint, the results highlight that stakeholder should implement policies and programs related to public organizational performance with a strong consideration of organizational agility. The research also discusses recommendations for multiple opportunities in which agility-based research can promote critical social and institutional success. This dissertation examines organizational agility in public entities such as U.S. Federal Agencies, elucidating its function within such institutions. The study underscores how agility fosters success and thwarts the consequences of its underutilization, which often hinders service and resource distribution, impeding societal and community advancement. It assesses the demographics affected by these outcomes and formulates strategies for agility's effective implementation to boost efficiency and societal progress.

Organizational agility, characterized by adaptability and proactiveness, can prevent institutional failures that obstruct progress amid multiple objectives, shifting economic and political climates, and cumbersome bureaucratic systems. These impediments are prominent in public organizations, highlighted by suboptimal performances and failures to meet challenges, with the mishandling of healthcare and educational policies during the COVID-19 pandemic as a notable instance. The study reveals a gap in existing public affairs literature regarding organizational agility, suggesting a critical shortfall. Addressing this, the research develops a theoretical model of agility in public organizations, emphasizing its importance. Hypotheses posit that organizational agility is shaped by organizational justice, which is, in turn, influenced by servant leadership. The theory is examined through data from the Federal Employee Viewpoint Survey using Partial Least Squares Structural Equation Modeling. The analysis generally substantiates the hypotheses, linking agile organizations with superior performance and underscoring the significance of leadership and justice in cultivating agility.

In conclusion, this research contributes a validated theoretical framework for organizational agility in the public sector. Practically, it advises stakeholders to consider agility in policies and programs concerning public organizational performance and outlines multiple areas where agility-focused research can enhance societal institutional success. The study reveals a gap in prior public affairs literature regarding organizational agility, suggesting a critical shortfall. Addressing this, the study develops a theoretical model of agility in public organizations, emphasizing its importance.

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Shuktika Chatterjee
Effects of Loading Age and Transverse Reinforcement Ratio on Collapse Resistance of RC Frame Beams under High Sustained Loadshttps://digitalscholarship.unlv.edu/thesesdissertations/4872https://digitalscholarship.unlv.edu/thesesdissertations/4872Fri, 14 Jun 2024 18:08:53 PDT<![CDATA[

Catastrophic progressive collapses of reinforced concrete (RC) frame buildings can be triggered by column failure. In such a scenario, the beams supported by the failed column shall be able to form an alternative load path guarding the building against collapse. The compressive arch action passively generated after losing a column has been identified as an effective load-resisting mechanism for axially restrained RC frame beams. However, the beams need to continuously carry the redistributed gravity loads sustaining in the structural system. Past research predominantly focused on the short-time collapse resistance of RC beams and little is known about their time-dependent response under high sustained loads. Therefore, sustained loading tests were performed on three RC beam-column subassemblies to study their long-term collapse resistance provided by the compressive arch action after losing a supporting column. The major test variables included loading age (between 50 and 267 days) and beam transverse reinforcement ratio (0.327%, 0.436%, and 0.655%). The specimens were tested at high sustained loads of 80% and 90% of the nominal short-term loading capacity under compressive arch action. The performance of a specimen tested in an earlier study was used as a basis to identify the effects of loading age and transverse reinforcement ratio on the time-dependent response of RC frame beams under high sustained loads. The experimental results indicated that younger loading age and lower transverse reinforcement ratio cause greater second order effects associated with creep-induced deformation, thereby decreasing the sustained loading capacity of beams. Additionally, Poisson’s ratio of concrete cover is a suitable indicator for the impending failure of RC frame beams under sustained loads. Potential failure was identified by a rapid increase in Poisson’s ratio due to tertiary creep, which occurred between 20 to 40 minutes before the sustained loading capacity was exhausted.

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Taiga Cibulka
Factors Associated with Caregiver Responsive and Non-Responsive Feeding Styles in Clark County, Nevadahttps://digitalscholarship.unlv.edu/thesesdissertations/4870https://digitalscholarship.unlv.edu/thesesdissertations/4870Fri, 14 Jun 2024 18:08:52 PDT<![CDATA[

Early childhood obesity has increased significantly over the last few decades, reaching epidemic levels in the United States. Many interventions exist to alleviate early childhood obesity; however, little focus is on preventing obesity-related risks for children under two. High-quality child-caregiver interactions are deemed critical for preventing early childhood obesity development, but there is little information on the socio-ecological factors that influence a caregivers' feeding styles. This study examined socio-ecological factors associated with caregivers' feeding styles (responsive vs. non-responsive) for infants under two in Clark County, Nevada. This cross-sectional study utilized a survey targeted to caregivers (18 and older) with infants under two years old living in Clark County, Nevada. Descriptive analysis and a logistic regression following a hierarchical modeling approach were used to determine the associations between household, maternal, and infant characteristics, pregnancy and prenatal care, maternal mental health, infant feeding, and caregiver feeding styles. We found infant and maternal socio-demographic characteristics associated with responsive and non-responsive feeding styles (e.g., mother’s age, education, infant’s insurance, and weight perception). Additionally, we found that household, maternal mental health, and pregnancy and prenatal care factors were associated with non-responsive feeding styles (e.g., household income, water insecurity, prenatal care, WIC enrollment, depression risk, and anxiety risk). Our study provides insights into socio-ecological factors influencing dissimilarities in caregivers' feeding styles that could be used to tailor educational approaches to address disparities in early childhood obesity.

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Amanda Castelo Saragosa
Investigation of the Chemical and Electronic Structure of a 2H Phase MoS<sub>2</sub> Single Crystalhttps://digitalscholarship.unlv.edu/thesesdissertations/4868https://digitalscholarship.unlv.edu/thesesdissertations/4868Fri, 14 Jun 2024 18:08:51 PDT<![CDATA[

Molybdenum disulfide has a wide range of applications in energy conversion devices, like thin-film solar cells, batteries, bio sensors, and more. Although the properties of MoS2 and other transition metal dichalcogenides (TMDC) have been widely studied, disagreements and discrepancies regarding its electronic structure remain.

In this thesis, a highly-oriented synthetic 2H phase MoS2 single crystal is investigated using a toolchest of spectroscopic techniques to uncover its chemical and electronic properties. Lab-based x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), inverse photoemission spectroscopy (IPES), and low energy electron diffraction (LEED) were performed at UNLV and combined with resonant inelastic soft x-ray scattering (RIXS) at the Advanced Light Source (ALS), Lawrence Berkeley National Laboratory. Together with theoretical calculations of the density of states and band structure, an in-depth picture of MoS2 properties is painted. In addition, the effects of mechanical exfoliation on the chemical and electronic environment of the MoS2 crystal surface is discussed. The results are compared to past studies and the established knowledge of the electronic structure of MoS2.

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Mary Blankenship
Assessing the Risk of West Nile Virus in the Southwestern United Stateshttps://digitalscholarship.unlv.edu/thesesdissertations/4869https://digitalscholarship.unlv.edu/thesesdissertations/4869Fri, 14 Jun 2024 18:08:51 PDT<![CDATA[

Climate change is an increasing public health threat that has been shown to influence Culex mosquito populations, the vectors of West Nile Virus (WNV). The main objective of this study was to determine which variables are most associated with WNV in the Southwest United States, defined herein as: California, Nevada, Arizona, and Utah. A Poisson regression model was used to analyze total cases from 2004-2020 using the following predictors: mosquito season temperature average, mosquito season precipitation average, bodies of water, and protected lands. Results indicated that precipitation average (P =.014) and the interaction between precipitation and temperature (P=.024) were significant. An increased average precipitation led to a decline of Relative Risk (RR) at .001, while the interaction of the 2 variables led to a slight increase in RR at 1.092. Predicted cases from 2004-2020 were calculated using the predictors selected in the final model (Table 2) using SPSS and compared with total cases at the county level (Figure 1). Both maps visualized a larger concentration of cases in California and in counties with large metropolitan cities, however, the predicted cases map showed a more geographically widespread risk of cases compared to the latter. Since 2004, there has been an overall decline of total cases. More research is suggested to investigate this phenomenon. The model can be utilized to establish areas of concern when developing mosquito surveillance or preventative measures in the Southwestern United States.

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Bradon Bucher
An Exploratory Pilot Study on Generating an Emergency Evacuation VR Experience for a Real-Life Building Without Existing BIM or Floor Planshttps://digitalscholarship.unlv.edu/thesesdissertations/4866https://digitalscholarship.unlv.edu/thesesdissertations/4866Fri, 14 Jun 2024 18:08:50 PDT<![CDATA[

With the rising frequency of active shooter incidents and fire hazards in both private and public facilities, it is crucial to establish a strategy for an effective emergency evacuation response for minimizing its consequences. Modern technological advancements such as virtual reality (VR) and game engines offer the potential to serve as valuable evacuation training tools within a virtual environment, aiding real-time decision making. Previous studies highlight the benefits of using VR simulations for emergency evacuation training, enhancing safety; however, two challenging factors exist that hinder their application. First, many existing structures (especially for older buildings) lack an available computer model/approach. Second, creation of a computer model for these structures face challenges, being time consuming and requiring substantial resources. When a digital model such as BIM (Building Information Modeling) is not readily accessible, such VR training requires an expeditious generation of 3D environment. In response, this research presents an employable approach for creating a virtual environment in VR using the Unreal Engine. For an implementable mode, it should be able to replicate the building evacuation environment with authenticity, incorporating successful aspects (i.e., emergency signages, opening doors, time measurement, non-player characters) from previous studies that had access to BIM models. Additionally, an exploratory pilot study is conducted to execute the approach, assessing its feasibility measures, effectiveness, and comparison against existing methods. The outcome is an expeditious method to create an efficient and relatively realistic VR virtual environment, enabling building occupants to engage in emergency evacuation response training, thereby better preparing for unforeseen catastrophic events.

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Naveed Ahmed
Development, Voice, and Vulnerability: A Rhetorical Analysis of the Policy-Making Discourse Regarding the Paris Agreement as an Organizational Response to Climate Changehttps://digitalscholarship.unlv.edu/thesesdissertations/4867https://digitalscholarship.unlv.edu/thesesdissertations/4867Fri, 14 Jun 2024 18:08:50 PDT<![CDATA[

On December 12, 2015, the Paris Agreement was officially ratified by 196 sovereign entities. This treaty represents a global call to action to ameliorate the impact of human activities on our environment, and it creates a means of cooperation through financial support and transparent industrial practices with the goal of promoting accountability across the world. This treaty and the discourse surrounding it present fertile ground for the academic understanding of persuasive practices in policy-making. By examining the rhetorical implications of the Paris Agreement as a global policy, scholars can gain new insight about the communities represented in the conversation as well as the power dynamics involved in the process. I argue that the Paris Agreement employs rhetorical frames that give voice to particular communities and results in a repackaging of imperialist, financial frameworks. I propose that the language and discourse used to construct this treaty showcases a series of strategies used to demarcate which communities have voice throughout this policy-making process. I examine this process through the theoretical lens of both voice and Interorganizational Authority (IA). The main themes analyzed in this dissertation are (1) the establishing of economic frames through “development” narratives, (2) the rhetorical construction of “leadership” within collaboration, and (3) the complexities of defining “vulnerability” in the context of a policy problem. I seek to further academic understanding of these dynamics by conducting a rhetorical analysis of the Paris Agreement as a text as well as examining U.S. Congressional and Presidential discourse surrounding the Agreement as an example of how one member party (that has fluctuated between joining and leaving the Agreement) conceptualizes its participation.

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David Almanza-Canas
Unraveling Water Quality Issues in the Colorado River Basin: Utilizing Remote Sensing Satellite Images, Statistical, and Machine Learning for Improved Monitoringhttps://digitalscholarship.unlv.edu/thesesdissertations/4865https://digitalscholarship.unlv.edu/thesesdissertations/4865Fri, 14 Jun 2024 18:08:49 PDT<![CDATA[

This research was aimed at exploring innovative and cost-effective tools in understanding the spatiotemporal variability of water quality parameters in the Colorado River Basin (CRB), which includes the Colorado River and major reservoirs and lakes in the USA including Lake Mead. The river which arises in the state of Colorado and empties into the Republic of Mexico at the Gulf of California, is a source of water to seven US states and the Republic of Mexico and provides water to about 40 million people and million acres of farmlands in seven states in the western US and the Republic of Mexico. Monitoring of water quality parameters (WQPs) has been traditionally carried out using field and laboratory methods. Although these methods offer standardized and accurate means of measuring these WQPs, they face some limitations including limited coverages, high labor and laboratory costs, and limited spatiotemporal sampling frequencies.

This study applied and integrated statistical techniques including descriptive and inferential statistics, remote sensing (RS) images, and machine learning (ML) models categorized as standalone and ensemble models as cost-effective tools to estimate the varying spatiotemporal concentrations of WQPs in Lake Mead and the Colorado River system. RS spectral signatures from Sentinel-2A/B Multi-Spectral Instrument (MSI) and Landsat 8 Operational Land Imager (OLI) images were retrieved from the Google Earth Engine (GEE) repository for the study.

This research used field data collected on Lake Mead by the cities of Las Vegas, Henderson, North Las Vegas, and the Clark County Water Reclamation District to ensure compliance with the Nevada Division of Environmental Protection (NDEP) National Pollutant Discharge Elimination System (NPDES) permits. Water quality data on the Colorado River was also obtained from the United States Geological Survey (USGS) data repository.

The approach utilized in this study involved conducting a comprehensive review of WQPs monitoring using RS applications as well as an overview of strengths and limitations of the conventional and RS measurement of WQPs of concern namely total dissolved solids (TDS), total suspended solids (TSS) and the implications of these WQPs on the ecosystem.

Statistical analyses were performed to assess the spatiotemporal distributions of TDS and TSS along the Colorado River to understand the variabilities and trends of these parameters. Key WQPs including TDS, TSS, dissolved oxygen (DO), and temperature were also studied in Lake Mead to understand the impact of hydrological variables and lake stratification in the lake on these parameters.

Additionally, the study employed machine learning (ML) models as an effective tool to estimate TDS in Lake Mead using electrical conductivity (EC) and temperature which are simpler, inexpensive, and takes less time. Results produced from the analysis showed that the eXtreme Gradient Boosting (XGBoost) algorithm was the best-performing ensemble model on the external validation datasets with R2 of 0.81 and RMSE of 34.19 mg/L. Another objective includes the employment of Landsat 8 OLI and Sentinel-2 MSI images for the estimation of the concentration of optically inactive TDS in Lake Mead. The Gradient Boosting Machine (GBM) and XGBoost algorithms were found to be generally showing extremely efficient capabilities in estimating TDS across all three datasets (training, testing, and external validation), respectively for the images from Sentinel-2 and Landsat 8 OLI sensors with evaluations on the external validation derived as 0.99, 9.07 mg/L, and 7.06 mg/L, respectively for R2, RMSE, and MAE for TDS estimations with Sentinel-2 images using GBM and with that of Landsat 8 OLI also yielding 0.95, 21.15 mg/L, and 15.89 mg/L, respectively for R2, RMSE, and MAE using the XGBoost algorithm. The use of GBM with the respective optimal features and hyperparameters described in this study was therefore proposed for the future estimation of TDS in Lake Mead using the Sentinel-2 images. This research also evaluated the potential of using remote sensing and machine learning to retrieve the concentrations of optically active TSS and optically inactive TDS in the Colorado River. The analysis found that ensemble algorithms such as the XGBoost were the optimal estimators for TDS using images from both Sentinel-2 MSI and Landsat 8 OLI with performance on the external validation derived as 0.99, 26.52 mg/L, and 19.19 mg/L, respectively for R2, RMSE, and MAE for Sentinel-2 images. The XGBoost algorithm yielded R2, RMSE, and MAE of 0.97, 35.82 mg/L, and 27.90 mg/L, respectively. The AdaBoost algorithm was found to be the best model for TSS estimations on the external validation 0.92, 29.48 mg/L, and 24.64 mg/L, respectively, for R2, RMSE, and MAE for the Sentinel-2 image. The RF model was found to be the optimal model for TSS estimations with the Landsat 8 OLI with reported R2, RMSE, and MAE of 0.90, 32.80 mg/L, and 22.91 mg/L, respectively.

The study therefore proposed the utilization of XGBoost with its hyperparameters and optimal or best features for the estimation of TDS for images from both sensors. The AdaBoost and RF models, together with their hyperparameters and the optimal features, respectively, for the Sentinel-2 MSI and Landsat 8 OLI.

The findings from this study provide key stakeholders, water resources managers, and researchers with perspectives into the spatiotemporal dynamics of WQPs in waterbodies in Lake Mead as well as a cost-effective tool for retrieving water quality data in the basin to improve monitoring efforts of the fast-depleting water resources.

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Godson Ebenezer Adjovu
Digital Scholarship@UNLV (2024)

FAQs

What counts as digital scholarship? ›

It encompasses a broad spectrum of activities aimed at leveraging the potential of digital resources in academic pursuits. The domains traditionally linked with digital scholarship encompass digital humanities, digital sciences, digital social sciences, digital art, and data science.

How to get a full ride scholarship to UNLV? ›

Scholarship Criteria
  1. Be enrolled in a minimum of 12 credits.
  2. Demonstrate financial need based on Free Application For Federal Student Aid (FAFSA)
  3. Have a minimum 3.0 GPA.
  4. Be a Nevada resident.
  5. Be a first-generation student.

What is an example of a digital scholarship? ›

Digital scholarship encompasses both traditional forms of digital media such as online scholarly databases, e-mail correspondence, and digitized academic collections, and newer forms such as social media, including Twitter, blog sites, and other hubs of online collaboration.

What is the difference between digital scholarship and digital humanities? ›

Digital Scholarship is an interdisciplinary framework that focuses on the development, utilization and criticism of digital content and technologies in teaching, research, and scholarship. Digital Humanities applies a humanistic lens to this framework.

How to evaluate a digital scholarship? ›

How to Evaluate Digital Scholarship
  1. Fundamentals for Initial Review: The work must be evaluated in the medium in which it was produced and published. ...
  2. Crediting: Digital projects are often collaborative in nature, involving teams of scholars who work together in different venues over various periods of time.

How much is digital responsibility scholarship? ›

The winner will receive a $1,000 scholarship.

What are the 2 most common types of scholarship? ›

There are two types of scholarships that most people mention: merit and need-based. At a closer look, there are more diverse ways to categorise them, ways that can increase your chances of getting a scholarship.

What is the Bill Gates Scholarship? ›

About the Scholarship

The Gates Scholarship recognizes minority high school seniors who have excelled academically and demonstrated motivation to succeed in college. Applicants will be reviewed for leadership abilities exhibited through participation in extracurricular activities and community service.

How do you keep track of scholarship money? ›

Creating lists or spreadsheets with scholarship details and deadlines can help them stay on track. Details are crucial - applicants should accurately track specific elements like scholarship providers, eligibility criteria, deadlines, due dates, required documents, contact information, etc.

What counts as digital humanities? ›

Digital humanities incorporate key insights from languages and literature, history, music, media and communications, computer science and information studies and combine these different approaches into new frameworks.

What is an example of digital humanities? ›

Compiling and analysing social media content. Compiling and annotating audio-visual databases (audio, images and video). Immersive technologies, such as 3D virtual reconstruction, augmented reality, and virtual worlds. Crowd-sourcing (sometimes called citizen science).

Do scholarships check social media? ›

Remember, many scholarship committees will now search for you online and they will take note of both positive and negative information. You can also network for available scholarships through social media sites. This means reaching out to people and letting them know that you're on the hunt for scholarships.

What counts as scholarship in academia? ›

Scholarship can take many forms. Regardless of the form in which scholarship is presented it should: a) Result in a product or artifact that reflects one's professional and academic expertise; b) Be reviewed by disciplinary peers external to the campus community; and c) Be disseminated beyond the campus.

What qualifies you for this scholarship? ›

One of the most common requirements for scholarships is academic achievement. Organizations typically assess your academic achievements by looking at your GPA, the classes you took, and your performance on standardized tests (like the SAT or ACT). These credentials show how well you have performed in academics so far.

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