Digital Commons Network^™

Numerical Studies Of Regularized Navier-Stokes Equations And An Application Of A Run-To-Run Control Model For Membrane Filtration At A Large Urban Water Treatment Facility, Jeffrey Belding

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation consists of two parts. The first part consists of research on accurate and efficient turbulent fluid flow modeling via a family of regularizations of the Navier-Stokes equation which are known as Time Relaxation models. In the second part, we look into the modeling application for the filtration/backwash process at the River Mountains Water Treatment Facility in Henderson, NV.

In the first two chapters, we introduce the Time Relaxation models and their associated differential filter equations. In addition, we develop the regularization method which employs the Nth van Cittert deconvolution operator, which gives rise to the family of models. …

The Spark That Lit The Match: The Use Of Petitions And The Emergence Of Antislavery Politicians In The Movement To Abolish Slavery In The District Of Columbia, 1816-1829, Timothy Brown

UNLV Theses, Dissertations, Professional Papers, and Capstones

The United States capital, Washington, D.C., became the focus of antislavery advocates in their quest to eliminate the domestic slave trade and slavery. By the War of 1812, the domestic slave trade was thriving in the capital. However, many saw it as particularly embarrassing to a nation predicated on the concept of freedom. This embarrassment was even felt by proslavery Southerners. Beginning in 1816, an attempt to restrict the trade in the Capital occurred when Virginia Congressman John Randolph called for the destruction of the domestic slave trade there. Despite being proslavery, he argued that the federal government, as the …

Physiological And Mechanical Comparisons Between Clipless And Flat Pedals, Katelyn Conroy

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to investigate the physiological and mechanical comparisons between clipless and flat pedals. Participants (n=4) completed two at-home 20-minute FTP tests: using clipless and flat pedals using Zwift. The order of conditions were randomized for each participant. Participants used their personal Smart Trainers, clipless pedals, and cycling shoes while flat pedals were provided (Syun-LP, Road Bike Platform Pedals). Power, heart rate and cadence were recorded and used for analysis. All dependent variables were compared using paired t-tests. Power was significantly greater for clipless (226.7 ± 46.2 W) vs. flat (215.2 ± 41.8 W) pedals (p …

The Implementation Of Tribal Provisions From The Vawa 2013 Reauthorization, Deejay E. Chino

UNLV Theses, Dissertations, Professional Papers, and Capstones

Recent changes in VAWA allows tribes – for the first time – to prosecute non-Indians for intimate partner violence. In order to do so, however, tribes have to first meet specific federal mandates. Implementation of federal regulatory policy by American Indian tribes is a dynamic and complex process but there is a dearth of information on the challenges tribes face or on factors that would facilitate successful implementation at the tribal level. This legislation has filled a serious gap in tribal jurisprudence but not all tribes are able to meet requirements, which include having specific legal codes and justice resources. …

Identifying Risk Factors For Ptsd Symptom Clusters In Maltreated, Multiracial Youth Using Nonparametric Modeling, Mallory Constantine

UNLV Theses, Dissertations, Professional Papers, and Capstones

Multiracial youth are one of the most at-risk racial groups for child maltreatment. Multiracial individuals are also more likely to report mental health concerns than other racial or ethnic groups. This study aimed to identify demographic and psychological risk factors that are unique to multiracial, maltreated youth with respect to PTSD symptoms (i.e., re-experiencing, hyperarousal, avoidance) through classification and regression tree (CART) analyses. Participants included 99 multiracial, maltreated youth directly following their placement in an emergency group shelter due to substantiated maltreatment. The first hypothesis was that female gender, English first language, questions related to guilt and self-blame, and depressive …

Factors Influencing Us Residents' Willingness To Engage In Domestic Medical Tourism, Hananeh Derakhshan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Domestic medical tourism is a niche market in the medical tourism industry. The purpose of this study was to determine the association of different attributes on U.S residents’ willingness to participate in domestic medical tourism. Based on the medical tourism index (MTI) components, a total of fourteen possible attributes that may impact US residents’ willingness to seek out-of-town care were created and participants were asked to rate the importance of each attribute on their willingness to seek out-of-town care on a 10-point Likert scale. Using principal component analysis, the attributes were grouped into three components: (1) quality-of-care, (2) destination attraction, …

Student Perceptions Of Formative Feedback In Mathematics, Derek E. Fialkiewicz

UNLV Theses, Dissertations, Professional Papers, and Capstones

There exists a plethora of quantitative studies which show the effectiveness of quality formative assessment and feedback in the classroom setting (Butler, 1987; Nyquist, 2003; Irons, 2008; Baskula, 2010; Pradana et al., 2017; Hossain, 2018; Pinger et al., 2018). Wiliam (2018) suggests the perceptions of the recipients of the feedback must be considered to determine the most effective levels of feedback. Seidman (2019) explained many researchers in the United States study education, but very few focus on the perspectives of the students and teachers, whose experiences comprise schooling. This qualitative study focuses on the perceptions of Grade 8 Pre-Algebra students …

Material Handling With Embodied Loco-Manipulation, Jean Chagas Vaz

UNLV Theses, Dissertations, Professional Papers, and Capstones

Material handling is an intrinsic component of disaster response. Typically, first responders, such as firefighters and/or paramedics, must carry, push, pull, and handle objects, facilitating the transportation of goods. For many years, researchers from around the globe have sought to enable full-sized humanoid robots to perform such essential material handling tasks. This work aims to tackle current limitations of humanoids in the realm of interaction with common objects such as carts, wheelbarrows, etc. Throughout this research, many methods will be applied to ensure a stable Zero Moment Point (ZMP) trajectory to allow a robust gait while loco-manipulating a cart. The …

How Do Beliefs Come Into Play? An Examination Of The Influence Of Core Conceptions On Science Teachers’ Inquiry Lesson Plan Designs, Mehmet Fatih Dulger

UNLV Theses, Dissertations, Professional Papers, and Capstones

Teaching science through inquiry-based methodologies has been advocated by several governmental and professional organizations (National Research Council [NRC], 2000; NGSS Lead States, 2013); however, their use is not widespread. Why is this? What science teachers do in their classrooms is shaped by their beliefs, especially their beliefs about the nature of science, about the goals and purposes of school science and the goals of teaching science, and about the teaching and learning science. By critically examining these core conceptions and their influence on teacher lesson planning, this study aims to shed light on the role conceptions play when teachers design …

Factors Associated With Medication Decision Making In African American Families Of Children With Adhd: A Mixed Methods Study, Amy Glasofer

UNLV Theses, Dissertations, Professional Papers, and Capstones

Attention-deficit/hyperactivity disorder (ADHD) is the most common neurobehavioral pediatric disorder in the United States. Pharmacotherapy is a recommended component of treatment for ADHD. While medication treatment of ADHD is not optimized overall, minority groups experience medication treatment disparities. The persistently lower rates of medication treatment in minority groups may have culturally specific origins which cannot be generalized across minorities. The purpose of this dissertation was to assess and extend knowledge regarding medication decision making (MDM) in African American caregivers of children with ADHD. To assess the state of the science on ADHD disparities, a review of 41 descriptive studies exploring …

Polyvinyl Chloride Gels: Theoretical Modeling Of Their Actuation Mechanism And Characterization Of Their Properties, Zachary Frank

UNLV Theses, Dissertations, Professional Papers, and Capstones

Polyvinyl chloride (PVC) gels are an electroactive polymer smart material which has been considered in a variety of actuator applications. Their large deformation, fast response rates, optical transparency, and soft nature has made them a key area of interest in fields ranging from soft robotics to optics. PVC gels are made from PVC mixed with large quantities of plasticizer, such as dibutyl adipate (DBA). When a voltage is applied, the gel experiences an “anodophilic” deformation (in which it moves preferentially towards the anode). This unique characteristic is the result of a charge buildup near the anode surface, which creates electromechanical …

Party Central: Networks, Influence, And Party Change In The Us House Of Representatives, Sean M. Goff

UNLV Theses, Dissertations, Professional Papers, and Capstones

For decades, scholars have devoted considerable attention to the causes and processes of party change. In this dissertation, I offer a new theoretical framework that not only takes into account the behavior of Members of Congress, but also how that behavior is constrained and conditioned by the relationships they share with other Members. This web of relationships forms a party network, the structure of which changes as Member-to-Member relationships change over time. I also identify three mechanisms of party change: a Member of Congress shifting their position to align with another (assimilation); a Member being pushed to the periphery of …

The Experience Of Self-Coherence: Self-Coherence As The Hub Of All Needs, April Ursula Fox

UNLV Theses, Dissertations, Professional Papers, and Capstones

Self-coherence as the hub of all needs is a novel proposition made by Carol Dweck (2017), and not yet further explored. While supporting self-coherence with a comprehensive review of its presence within behavioral sciences, Dweck does not dive deeper into it, and offers an invitation for further research of its workings. In this study I respond to that invitation. I design a continuation to her theory. I also expand her theory to include what I have found to be missing, but essential, additional components that cannot be ignored within the context of self-coherence as a master sensor of needs. Finally, …

The Archetypal Female Image In Chinese National Opera: A Study Of Xi Shi, Xin Guo

UNLV Theses, Dissertations, Professional Papers, and Capstones

In contrast to traditional Chinese operas, the history of Chinese National Opera1 is only a few decades long. Some scholars believe that many Chinese operas are feminist and female-centered. However, from the aesthetic standard of women’s voice to the female character’s inner world, it is hard to say that one can describe these operas as feminist simply because women play leading roles or the female arias are more than male. This document will explain the observation by analyzing the portrayal of female archetypes in Chinese national opera and discussing how opera Xi Shi complies with or subverts the portrayal. The …

How Can We Reduce Racism? A Mixed Method Study Of Factors That Influence Attitudes Towards Social Change, Kindy Insouvanh

UNLV Theses, Dissertations, Professional Papers, and Capstones

The resurgence of social movements such as Black Lives Matter has provoked public discourse about racial inequality and efforts towards social change. The current study sought to better understand how young adults reason about racism reduction with a focus on racial allyship and collective action. The present study used mixed methods to identify strategies young adults believe different racial groups could do to reduce racism and investigate the influence that individual factors have on reasoning about social change. Here, I present emergent themes to describe racism reduction strategies from a large and racially diverse sample of undergraduate students (N= 428). …

Improving Pedestrian Safety With The Implementation Of The Demand-Responsive Transverse Rumble Strip As A New Traffic Safety Countermeasure, Md Shakhawat Hossen

UNLV Theses, Dissertations, Professional Papers, and Capstones

The traditional TRS has been extensively used as a traffic calming device to provide cognitive alerts in the form of sound and vibration to drivers. However, TRS always remains fixed on the road and thus exerts cognitive alerts, irrespective of any potential downstream hazards. Moreover, the continuous exposure to rumble strips has been identified as a source of discomfort and annoyance for drivers, which limits its application to potentially useful scenarios. This study explores a rumble strip design with dynamic behavior named as Demand-Responsive Transverse Rumble Strip (DRTRS) in order to address the limitations of static TRS. The study incorporates …

The Role Of Working Memory In Fraction Arithmetic: Eye Movements During A Dual Task, Krystal Kamekona-Mendoza

UNLV Theses, Dissertations, Professional Papers, and Capstones

Fractions are first introduced at the elementary school age, yet difficulty with fraction computation (i.e., adding, subtracting, multiplying, and dividing) continues to persist throughout adulthood. Research suggests that fraction knowledge is predictive of future math achievement and success in algebra. Given the early age at which this concept is introduced and the critical role that it plays in future mathematics success, it is important to better understand the cognitive mechanisms involved in fraction computation and why students continue to struggle with this concept. The role of executive function (e.g., attention, inhibition, working memory) in fraction arithmetic is complex. While working …

Quaternary Ammonium Compounds As Precursors To Disinfection Byproducts, Padmanabhan Krishnaswamy

UNLV Theses, Dissertations, Professional Papers, and Capstones

Disinfection of drinking water is crucial for providing a safe potable water supply. Some of the most common disinfectants employed are chlorine, chloramines and ozone. While these disinfectants successfully inactivate pathogenic microorganisms, they simultaneously react with inorganic or organic precursors to form toxic byproducts, most commonly referred to as disinfection byproducts (DBPs). While there is a wide variety of organic matter and disinfection byproducts known, in this study we have looked into the potential of certain quaternary ammonium compounds (QACs) to act as precursors to form DBPs, namely trihalomethanes (THMs), haloacetonitriles (HANs) and nitrosamines.

The ubiquitous nature of QACs in …

A Human-Embodied Drone For Dexterous Aerial Manipulation, Dongbin Kim

UNLV Theses, Dissertations, Professional Papers, and Capstones

Current drones perform a wide variety of tasks in surveillance, photography, agriculture, package delivery, etc. However, these tasks are performed passively without the use of human interaction. Aerial manipulation shifts this paradigm and implements drones with robotic arms that allow interaction with the environment rather than simply sensing it. For example, in construction, aerial manipulation in conjunction with human interaction could allow operators to perform several tasks, such as hosing decks, drill into surfaces, and sealing cracks via a drone. This integration with drones will henceforth be known as dexterous aerial manipulation.

Our recent work integrated the worker’s experience into …

Determination Of The Presence Of Sars-Cov-2 In Environmental Surface And Air Samples From Public Areas In Las Vegas, Kristina Mihajlovski

UNLV Theses, Dissertations, Professional Papers, and Capstones

Contaminated surfaces and airborne spread are found to be among the main ways of coronavirus disease 2019 (COVID-19) transmission. Studies conducted in the hospital setting have shown that SARS-CoV-2 is found on frequently touched surfaces, personal protective equipment, and in air samples of patient isolation rooms. However, few environmental sampling studies have been done in public areas. Taking in consideration that COVID-19 cases may be symptomatic, presymptomatic, and asymptomatic, environmental monitoring may be essential for prompt detection of the virus. The objective of this study was to determine whether SARS-CoV-2 can be detected on environmental surfaces and from air samples …

Calculating The Learning Rate Of A Neural Network Using A Genetic Algorithm, Eric Miller

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the field of Computer Science, neural networks and genetic algorithms have become very popular tools in solving complex problems. Because of this growing popularity, there has been several attempts to combine the two concepts. Some of these attempts focused on using genetic algorithms to determine the best architecture, starting weights, or feature selection, to name of few of the applications. While a lot of the research that is available focuses on solving more than one element of the neural network design or is looking to use genetic algorithms to replace a part of the traditional neural network, such as …

Computational Sodium Heat Pipe Simulation In Three Dimensions For Transient Nuclear Reactor Analysis With Variable Surface Heat Flux, Valerie Jean Lawdensky

UNLV Theses, Dissertations, Professional Papers, and Capstones

Heat pipes are used to transfer heat through phase change in a liquid/vapor contained in a metal tube. They are passive devices that require no pumps to circulate the fluid and can transfer heat far more efficiently than a solid copper rod of the same diameter. They are commonly used in laptop computers where copper heat pipes filled with water take heat away from the CPU and transfer the heat to air through a heat exchanger. Heat pipes were also used in the Kilopower nuclear reactor where higher temperatures required sodium as the working fluid with stainless steel tubes. Computer …

Leaders’ Strategies For Motivating The Millennial Generation To Sustain High Levels Of Performance, Juan Alvarez

Walden Dissertations and Doctoral Studies

Failure to identify and implement strategies to address the needs of the Millennial workforce can lead to a decrease in productivity in the organization. The increasing number of Millennials in the workforce creates a challenge for many business leaders in maintaining or surpassing the productivity levels found in organizations where the baby boomer employees are the majority. Grounded in transformational leadership theory, the purpose of this qualitative single case study was to explore the strategies that warehouse supervisors use to enable Millennial employees to maintain or surpass productivity levels in organizations. Interviews were conducted with six warehouse supervisors who had …

Commentary: Zoom Into The Coronary Anastomosis During Coronavirus Disease 2019 (Covid-19), Danial Ahmad, Vakhtang Tchantchaleishvili

Division of Cardiology Faculty Papers

No abstract provided.

Giant Abdominal Aortic Aneurysms, Joshua I Ng, Tuong Nguyen, Anand Tarpara, Dawn Salvatore, Paul J Dimuzio, Babak Abai

Department of Surgery Faculty Papers

Giant abdominal aortic aneurysms (AAAs) are defined as AAAs >10 to 13 cm in the maximum transverse diameter. We have described a case of a patient who had presented for open repair of an 18-cm AAA and a review of reported cases of giant AAAs >10 cm in the maximum transverse diameter. Forty cases were compiled. The average maximum AAA diameter was 14.5 ± 4.1 cm. The AAA was ruptured on presentation in 12 patients (30%). Of the 40 cases, 34 (85%) were repaired with open surgery. The reported mortality was 15%. Despite the case complexity, five endovascular repairs were …

Strategic Social Media For Small Congregations, Heather R. Sparkman

Theses

Utilizing social media to draw and build a community of followers is the typical work of the modern Influencer and large organizations. But for a small church, using social media may seem like a wasteful or exasperating experience due to the sheer work that is involved in the enterprise and inconsistency brought on by a lack of strategic thought. The development of this assessment and philosophical metric focuses less on statistical metrics and more on stable principles that relate to values, context, and culture.

Student Engagement And Equitable Student Learning Outcomes, Douglas K. Harter

Dissertations

Student engagement is consistently shown by research to be a critical component of student learning. An opportunity to link variables of perceived student engagement, perceived student-teacher relationship and clarity, an in-person learning format, and a remote learning format presented itself when, in March of 2020, all Illinois public schools were mandated by Governor J.B. Pritzker to teach in a fully remote structure due to the COVID-19 pandemic. Student survey data results were examined using Wagner et al’s (2006) 4 C’s model to determine if there were statistically significant differences among student engagement and student-teacher relationships when compared across in-person and …

Radical Inclusion: An Engagement Model For Accountability Redesign, Natalie Neris

Dissertations

To ensure that Chicago Public Schools’ school accountability policy is equitable and representative of the insights and perspectives of those most impacted, this study advocates for CPS to enact a Radically Inclusive Stakeholder Engagement (RISE) policy to enforce a more inclusive policy redesign process. This policy advocacy document examines the history of school accountability through five intersecting domains: education, economics, social context, political context and moral/ethical considerations. Reflecting on my experience as a third-generation CPS student, a CPS parent, former teacher and school leader, I challenge the reader to consider the intention and impact of school accountability on Chicago’s students …

Gaze, Volume 8, Number 6

Gaze, 1979-1990

Co-Editors: Allen Cook, John Stilwell. Staff Writers: Carole Taylor, Bob Dumais. Typesetting and Layout: Allen Cook, Bob Dumais, Cecil McLeod, John Stilwell. Circulation: Cecil McLeod, John Stilwell, Bob Dumais. Advertising Manager: Bob Dumais.

Special thanks to Rhodes College and the Paul Barret Jr. Library for providing initial scanning of this collection.

Gaze, Volume 10, Number 8

Gaze, 1979-1990

Co-Editors: Allen Cook, John Stilwell. Staff Writers: Bob Dumais, Susan McKenzie, Vincent Astor, Ken Horton, Becky Caperton. Typesetting and Layout: Allen Cook, Bob Dumais, John Stilwell, Vincent Astor. Circulation: Cecil McLeod, John Stilwell, Bob Dumais. Advertising: Bob Dumais, Vincent Astor.

This is the first of two issues printed as volume 10, number 8.

This issue is noted as July and August.

Special thanks to Rhodes College and the Paul Barret Jr. Library for providing initial scanning of this collection.