Digital Commons Network^™

Accurate Flux Calibration Of Gw170817: Is The X-Ray Counterpart On The Rise?, E. Troja, B. O'Connor, G. Ryan, L. Piro, R. Ricci, B. Zhang, T. Piran, G. Bruni, S. B. Cenko, H. Van Eerten

Physics & Astronomy Faculty Research

X-ray emission from the gravitational wave transient GW170817 is well described as non-thermal afterglow radiation produced by a structured relativistic jet viewed off-axis. We show that the X-ray counterpart continues to be detected at 3.3 years after the merger. Such long-lasting signal is not a prediction of the earlier jet models characterized by a narrow jet core and a viewing angle ≈20 deg, and is spurring a renewed interest in the origin of the X-ray emission. We present a comprehensive analysis of the X-ray dataset aimed at clarifying existing discrepancies in the literature, and in particular the presence of an …

Teacher Preparation, Motivation, And Self-Efficacy: A Comparative Study Of New Teachers In Japan And The United States, Shaoan Zhang, Andromeda Hightower, Qingmin Shi

Teaching and Learning Faculty Research

Using the Teaching and Learning International Survey (TALIS) 2018, this study examines U.S. and Japanese new teachers’ initial teacher preparation (ITP), feelings of preparedness, motivations, and self-efficacy. The analysis of 355 U.S. and 433 Japanese new secondary teachers provided several findings. First, ITP in the U.S. more often included teaching in mixed-ability and multicultural settings, cross-curricular skills, and technology than Japan, and U.S. teachers felt more prepared than Japanese teachers in every category of preparation. Second, Japanese teachers were more likely to declare teaching as their first career choice and reportedly scored significantly higher on motivations to become a teacher …

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 …

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 …

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 …

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 …

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 …

Exploring The Latent Space Of Image Captioning Networks, Mikian J. Musser

UNLV Theses, Dissertations, Professional Papers, and Capstones

State-of-the-art image captioning models can successfully produce a diverse set of accurate captions. Previous research has focused on improving caption diversity while maintaining a high level of fidelity. We shift the focus from accuracy and diversity to controllability. We use a modified version of the traditional encoder-decoder network that allows the model to produce a meaningful and structured latent space. We then explore the latent space using several latent cartographic methods: lerp, slerp, analogy completion, attribute vector rotation, and interpolation graphs. Additionally, we discuss different categories of latent space and provide modifications for each of the cartographic methods. Finally, we …

Tinyml For Gait Stride Classification, Priyanka Rajendra

UNLV Theses, Dissertations, Professional Papers, and Capstones

Human gait classification and analysis become very important when a person has been diagnosed with a neurological disorder or has suffered an injury which has affected their ability to walk correctly. Gait strides are an important parameter to be studied as it helps the doctor to diagnose any underlying gait condition and evaluate what type of treatment suits the best for the patient’s recovery. Studying gait strides also helps athletes to improve their performance.In today’s world, machine learning has emerged as one of the most widely used technology for classification and analysis of gait characteristics. TinyML is a field of …

Turbulence Modeling Of Shock Boundary Layer Interaction In Hypersonic Flows, Sogol Pirbastami

UNLV Theses, Dissertations, Professional Papers, and Capstones

Over the past few years, renewed interest in hypersonic research has significantly increased. Some of the most challenging obstacles in hypersonic vehicles design are associated with the shock wave turbulent boundary layer interactions (STBLI). This can cause a severe jump in pressure along with aerothermodynamic loads, which might result in structural damages or engine unstarts of hypersonic vehicles. Understanding the complex characteristics of these flows requires comprehensive physical experiments and detailed CFD turbulence modeling. In this dissertation, CFD simulations of STBLI using different turbulent modeling based on a set of experiments of hypersonic flow over a large hollow cylinder flare …

Machine Learning Analysis Of Single Nucleotide Polymorphism (Snp) Data To Predict Bone Mineral Density In African American Women, Erick Githua Wakayu

UNLV Theses, Dissertations, Professional Papers, and Capstones

Osteoporosis is a debilitating disease in which an individual’s bones weaken, making bones fragile and more susceptible to fracture. While commonly found amongst postmenopausal Caucasian and Asian women based on previous studies, those of African descent (African American/Black) have largely been ignored when it comes to osteoporotic studies, especially when it comes to Genome Wide Association Studies (GWAS). From GWA studies, we gain access to single nucleotide poly-morphisms (SNPs) that may contribute to certain illnesses, such as osteoporosis. With low Bone Mineral Density (BMD) being one of the primary markers of potential osteoporosis, it is prudent that proper research is …

Hybridity, Ecocriticism, And Feminist Perspectives In She-Ra And The Princesses Of Power, Sarah Warso

UNLV Theses, Dissertations, Professional Papers, and Capstones

Children’s cartoons are growing increasingly nuanced in the twenty-first century. She-Ra and the Princesses of Power (2018) is an animated television series targeted towards young girls that includes themes of ecocriticism and feminism. The show does this by introducing cyborg, or hybrid, characters. My research explores how cyborg identities in children’s media and their feminist, ecocritical meanings in She-Ra and the Princesses of Power. The cyborg, as a feminist mythic hero, breaks down binaries and recodes communication between opposing forces. The She-Ra is filled with characters that inhabit multiple identities. The main character, Adora, identifies as both a former Evil …

Factors Influencing Service Robot Adoption: A Comparative Analysis Of Hotel-Specific Service Robot Acceptance Models, Ying Dong

UNLV Theses, Dissertations, Professional Papers, and Capstones

The market for service robots is expected to expand significantly owing to the increasing relevance of service automation under the outbreak of the COVID-19 pandemic. Despite the growing managerial interest in robotic applications in the hotel industry, current robotic research has been mostly conceptual with limited robot data on hand. In light of this issue, this paper will conduct a comparative analysis of hotel-specific service robot acceptance models between the Service Robot Acceptance Model (sRAM) and the Service Robot Integration Willingness (SRIW) framework. By identifying key elements of each service robot acceptance model, this paper puts an emphasis on investigating …

Data Analytics In Hotel And Integrated Resort Brands: An Evaluation Of Past Literature And Proposed Research For The Future, Luke Andrew Walocko

UNLV Theses, Dissertations, Professional Papers, and Capstones

Data analytics in hotel and integrated resort brands is a growing strategy implemented to support business decisions designed to generate revenue or save costs. This study utilizes a literature review of data analytics related publications to provide recommendations on future research topics to improve the quality of literature related to data analytics in hotel and integrated resort brands. The study is not limited to hospitality specific research and uses research from all industries to identify gaps in publications for hospitality scholars to explore. Three proposed research questions for future exploration were composed based on the comparison of literature written for …

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. …

From Language Comprehension Towards General Ai, Binay Dahal

UNLV Theses, Dissertations, Professional Papers, and Capstones

Language comprehension or more formally, natural language understanding is one of the major undertakings in Artificial Intelligence. In this work, we explore a few of the problems in language understanding using fixed deep learning models. Specifically, first, we look into question generation. Asking questions relates to the cognitive ability of language comprehension and context understanding. For that reason, making progress in question generation is significant. We introduce a novel task called “question generation with masked target answer” and propose various models and present the baseline result for the task. Next, we extend on the question generation task and develop a …

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 …

Monitored Compression Therapy: Using Smart Technology To Optimize The Treatment Of Lower Extremity Swelling, James Skelly

UNLV Theses, Dissertations, Professional Papers, and Capstones

Chronic Venous Insufficiency (CVI) and Venous Stasis Ulcers (VSUs) are symptoms which stem from diabetes – a disease effecting over 34 million people in the United States alone as of 2020. This Thesis details the design of a pressure-sensing garment used to enhance the treatment of CVI. The garment uses small force sensors (four levels: the insole of the foot, the lower leg, the lower calf, and the upper calf) to sense the pressure applied by a compression stocking. The sensed data is transmitted wirelessly via Bluetooth to a smartphone application that was developed to display the data and interface …

What Do General And Organic Chemistry Students Consider When Making Decisions About Acids And Bases? A Phenomenographic Study, Sarah Wood

UNLV Theses, Dissertations, Professional Papers, and Capstones

Chemistry students often struggle in organic chemistry courses. In fact, these courses are viewed by some as “weed-out” classes. There are many fundamental concepts covered in general chemistry that contribute to students’ ability to succeed in organic chemistry. One of those fundamental topics, and the focus of this study, is the topic of acids and bases. Acid–base topics are featured in both general and organic chemistry courses, and the interests of this study lie not only within the realm of organic chemistry but also general chemistry.

The purpose of this study was to determine both undergraduate general and organic chemistry …

Influence Of Saltwater Submergence On Geohydraulic Properties Of Sand: A Laboratory Investigation, Sudip Basack, Ghritartha Goswami, Sumanpran Sonowal, Moses Karakouzian

Civil and Environmental Engineering and Construction Faculty Research

Saline water intrusion into freshwater aquifers is a major geohydraulic problem relevant to coastal environment. Apart from contaminating the fresh groundwater resources, the saltwater intrusion alters the geotechnical properties of the aquifer materials, affecting the coastal water resource planning and management. The present study focuses on an in-depth laboratory investigation of the influence of saltwater submergence on the geohydraulic properties of sand. The fine sand sample was submerged under saline water of specified concentrations for specific periods, and the alteration in their engineering properties has been studied. It is observed that the specific gravity, dry density, and permeability of fine …

Characteristics Of Flow Over Rectangular Labyrinth Weirs With Round Corners, Omed S.Q. Yousif, Kawa Z. Abdulrahman, Wazira Qadir, Ahang S. Ali, Moses Karakouzian

Civil and Environmental Engineering and Construction Faculty Research

The hydraulic performance of round-cornered rectangular labyrinth weirs with varying weir heights and effective lengths has not been explored in the existing literature to the authors’ knowledge. The purpose of this experimental study was to see how the height and effective length of round-cornered rectangular labyrinth weirs affect their discharge efficiency. Nine flat-crested rectangular labyrinth weirs made of high-density polyethylene (HDPE) were tested in a rectangular flume under various discharges to fulfill the goals of this study. The discharge coefficients for the weirs were then calculated. The hydraulic efficiency of weirs with round corners increases as the weir height (P) …

Nonperiodic Type I Be/X-Ray Binary Outbursts, Rebecca G. Martin, Alessia Franchini

Physics & Astronomy Faculty Research

Type I Be/X-ray binary outbursts are driven by mass transfer from a Be star decretion disk to a neutron star companion during each orbital period. Treiber et al. recently observed nonperiodic type I outbursts in RX J0529.8-6556 that has unknown binary orbital properties. We show that nonperiodic type I outbursts may be temporarily driven in a low eccentricity binary with a disk that is inclined sufficiently to be mildly unstable to Kozai-Lidov oscillations. The inclined disk becomes eccentric and material is transferred to the neutron star at up to three locations in each orbit: when the neutron star passes the …

Data Of The Constructivist Practices In The Learning Environment Survey From Engineering Undergraduates: An Exploratory Factor Analysis, Chengcheng Li, Shaoan Zhang, Tiberio Garza, Yingtao Jiang

Teaching and Learning Faculty Research

This paper presents the dataset of a questionnaire on first-year engineering undergraduates’ perceptions of constructivist practices in the learning environment. The questionnaire with a 5-Likert scale was adapted from previous research. The sample consisted of 293 first-year engineering undergraduates in the southwest region of the United States. The online questionnaire was sent to participants who completed it voluntarily at the end of Fall 2019. A total of 274 of 293 participants completed the questionnaire with a response rate of 93.515%. Exploratory factor analysis was conducted to test the underlying factor structure of the questionnaire, which serves as a good reference …

Ab-Initio And Empirical Simulations Of Aluminum And Copper Metal, William Wolfs

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this work, I perform detailed calculations on the bulk and electronic properties of aluminum and copper metal. Originally, I was motivated by experimental work on the solidsolid phase changes in pure aluminum. These phase changes were well predicted by density functional theory(DFT) but difficult or impossible to predict using embedded atom method potentials(EAM). EAM potentials are in wide use to describe many properties of bulk materials, and it seemed worrying that something so basic as a phase change could not be predicted. I began running high precision calculations with DFT and compared the results to EAM potentials which had …

Independent And Combined Associations Between Multiple Lifestyle Behaviours And Academic Grades Of Inner Urban And Peri-Urban High School Students: A Cross-Sectional Study In Chongqing, China, Zhengjie Cai, Jinli Xian, Camila Araujo, Ziwei Zhang, Hongyu Zhou, Huan Peng, Manoj Sharma, Yong Zhao

Social and Behavioral Health Faculty Research

Objectives This study aims to assess the independent and combined associations between multiple lifestyle behaviours and academic grades of inner urban high school students (IUHSSs) and peri-urban high school students (PUHSSs). Design A cross-sectional study was conducted. Participants There are 1481 high school students (49.9% boys) in this study, who were enrolled from one inner urban and two peri-urban schools in Chongqing, China. Outcome measures Academic grades were assessed based on the students’ self-reported grade ranking in the last cumulative examination. Results In IUHSSs and PUHSSs, high frequency of sugar-sweetened beverage consumption was unlikely to obtain high academic grades (OR …

Statistical Measurements Of Dispersion Measure Fluctuations Of Frbs, Siyao Xu, David H. Weinberg, Bing Zhang

Physics & Astronomy Faculty Research

Extragalactic fast radio bursts (FRBs) have large dispersion measures (DMs) and are unique probes of intergalactic electron density fluctuations. By using the recently released First CHIME/FRB Catalog, we reexamined the structure function (SF) of DM fluctuations. It shows a large DM fluctuation similar to that previously reported in Xu & Zhang, but no clear correlation hinting toward large-scale turbulence is reproduced with this larger sample. To suppress the distortion effect from FRB distances and their host DMs, we focus on a subset of CHIME catalog with DM < 500 pc cm-3. A trend of nonconstant SF and nonzero correlation function (CF) at angular separations θ less than 10 is seen, but with large statistical uncertainties. The difference found between SF and that derived from CF at θ ≲ 10 can be ascribed to the large statistical uncertainties or the density inhomogeneities on scales on the order of 100 Mpc. The possible correlation of electron density fluctuations and inhomogeneities of density distribution should be tested when several thousands of FRBs are available.

Antagonistic Role Of Aqueous Complexation In The Solvent Extraction And Separation Of Rare Earth Ions, Pan Sun, Erik A. Binter, Zhu Liang, M. Alex Brown, Artem V. Gelis, Ilan Benjamin, Mrinal K. Bera, Binhua Lin, Wei Bu, Mark L. Schlossman

Chemistry and Biochemistry Faculty Research

Solvent extraction is used widely for chemical separations and environmental remediation. Although the kinetics and efficiency of this process rely upon the formation of ion-extractant complexes, it has proven challenging to identify the location of ion-extractant complexation within the solution and its impact on the separation. Here, we use tensiometry and X-ray scattering to characterize the surface of aqueous solutions of lanthanide chlorides and the water-soluble extractant bis(2-ethylhexyl) phosphoric acid (HDEHP), in the absence of a coexisting organic solvent. These studies restrict ion-extractant interactions to the aqueous phase and its liquid-vapor interface, allowing us to explore the consequences that one …

China's Important 2060 Carbon Neutrality Goal, Jason Jasper, Kimberly Nehls Ph.D.

Undergraduate Research Symposium Posters

Climate Change is a serious threat to global security and well-being. Many developed nations and some developing nations have made promises to become carbon-neutral (net zero emissions), or carbon-free by a specified time frame. China is a developing nation with high growth and has set a goal to be carbon-neutral by 2060. This study aims to determine how much China would need to reduce CO2 emissions to achieve this goal, and how it compares to other nations, using the most current data, and mathematical analysis. China produces the most CO2 in the world, almost twice as much as the United …