Digital Commons Network^™

High Performance Silicon Carbide Based Converters For Powertrain Electrification, Nan Lin

Graduate Theses and Dissertations

With the increasing concern towards environment protection, electric vehicles (EVs) and hybrid electric vehicles (HEVs) have become popular in recent years. They not only help reduce carbon emissions, but also come with other benefits such higher efficiency and better user experience. Many countries and vehicle manufactures have made their plans to keep up with this trend in vehicle electrification. Powertrain is an assembly of components in a vehicle that pushes it forward. As for EVs and HEVs, their powertrains are composed of one or more power electronics converters, which are significant to the system. Silicon carbide MOSFETs have shown superior …

The Kids Aren’T Alright: Examining The Spatial Concentration Of Drug Crime Near Schools In Little Rock, Arkansas, Jason Neeley

Graduate Theses and Dissertations

In the last two decades, violence and death stemming from drug activity has become a concern to communities across the country. Increasingly, policymakers and law enforcement agencies have sought to understand where drug activity is located, including in and around schools, and why some places are more susceptible to drug problems than others. The current study explores two related questions: (1) How do drug crimes spatially pattern around schools? and, in turn, (2) What are the neighborhood-level predictors of the concentration of drug crime? Focusing on Little Rock, Arkansas, I examine the spatial distribution of drug offenses and overdoses within …

Talking About Aphasia: A Social Media Analysis Of What Individuals With Aphasia And Communication Partners Convey About Functional Discourse, Anna Williams

Graduate Theses and Dissertations

This study aimed to blend what we know about aphasia and functional communication. Specifically, how individuals with aphasia are functionalizing communication on the social media platform of YouTube. Extensive clinically significant literature exists on functional communication within speech-language pathology that provides practical guidance for clinical applications. Moreover, an emerging theoretical framework on functional communication and aphasia has sparked fresh insights, particularly from the perspective of individuals with aphasia. This perspective holds promise for exploring how individuals and their families leverage social media for functional communication. This study aims to integrate established clinical research findings on functional communication with the evolving …

Partial Immersion Using Body Bags For Treating Exertional Hyperthermia, Diane Olivia Zashin

Graduate Theses and Dissertations

Context: Research suggests that ATs lack compliance with EHS management and do not adopt gold-standard recommendations for EHS. Body bags filled with ice and water may offer an alternative method of cold-water immersion (CWI) that is more portable and accessible than rigid cold tubs. Anecdotally, this treatment has been used successfully in ambulances and at mass participation events for exertional heat illness treatment. The purpose of this study was to determine whole-body cooling rates when using body bags (BB) to facilitate partial CWI to treat exertional hyperthermia. Methods: Nine (8 male) participants (24 ± 4y, 175 ± 7cm, 83.6 ± …

A Mixed Methods Exploration Of Interoceptive Awareness In Adults Who Stutter, Hazel Malcolm

Graduate Theses and Dissertations

Stuttering is commonly described as a disorder of speech fluency characterized by primary speech behaviors that are judged by external observers to be typical of stuttering, including part-word repetitions, prolongations, and blocks (i.e., silent prolongations or postural fixations). Despite wide use in the field of speech-pathology, definitions focusing on these ‘primary’ behaviors have also been criticized as ‘surface’ or ‘perceptual’ definitions that favor the experience of a listener over that of the speaker. Recent qualitative evidence suggests that, when asked, adults who stutter (AWS) instead define stuttering as an internal feeling or awareness of being ‘stuck’ that is surrounded by …

A 10 Kv Sic Mosfet Power Module With Optimized System Interface And Electric Field Distribution, Xiaoling Li

Graduate Theses and Dissertations

This dissertation introduces a holistic and systematic design methodology tailored to the 10 kV silicon carbide (SiC) MOSFET power modules to achieve multi-objective optimization with enhanced electric-field (E-field) distribution, minimized common-mode (CM) parasitic capacitance, and reduced system-level parasitic inductances. The proposed approach encompasses two innovative techniques: 1) an electric-potential-oriented module-system interface to reduce system-level parasitic inductance while maximizing insulation capability; 2) stacked substrates with patterned middle layer copper to alleviate the E-field concentration at the triple-point and reduce the maximum E-field without compromising on thermal resistance. The effectiveness of these innovative approaches is substantiated through the development of a 10 …

A Mobile Application Intervention For Insomnia Among College Students, Veronica Floyd

Graduate Theses and Dissertations

Previous studies have found that the prevalence of insomnia among college students is high. This has implications for students mental and physical well-being, academic performance, and the onset of more chronic insomnia symptomology. Cognitive Behavioral Therapy for Insomnia (CBT-I) is the front-line treatment for insomnia, but cost and time are often barriers to treatment access. The goal of this study was to test the feasibility, acceptability, and efficacy of a more cost-effective self-guided version of CBT-I (via mobile application). Fifty-five college students, who were mostly women (82%) and mean age 19.3 (SD = 2.3) years with moderate insomnia symptoms were …

Determination Of Ileal Digestible Phosphorous Values In Various Inorganic Sources Meat And Bone Meal Sources, Jay Hampton

Graduate Theses and Dissertations

Concerns around the economic and environmental consequences of suboptimal or excess dietary P levels in broiler diets has led to increased interest in determining ileal P digestibility values for feed ingredients. Therefore, two experiments (EXP) were conducted to determine the apparent (AID) and standardized ileal digestibility (SID) of P in various inorganic phosphates and meat and bone meals (MBM) using the direct method. In both EXP 1 and 2, ileal samples were collected at 22 d post-hatch from birds fed semi-purified diets based on dextrose and corn starch containing test ingredients and one N and P free (NPF) diet for …

Evaluating The Association Between Daily Fluctuations In Sleep And Blood Pressure, Mara Egeler

Graduate Theses and Dissertations

Hypertension is a major contributing factor for heart disease, with nearly half of US adults meeting criteria. While studies have begun to examine the relationship between insomnia and blood pressure (BP), little is still known regarding the relationship between daily fluctuations in sleep and BP. This study aimed to provide further clarification on the role insomnia plays in the development of hypertension, including the impact that daily fluctuations in sleep have on fluctuations in BP. Participants included 61 adults from the greater Northwest Arkansas area (63.9% White, 67.2% Female, 30-79 y) who completed 10 consecutive days of sleep and blood …

Characterizing The Role Of Chemo-Mechanical Couplings In The Activation Process Of Proteins That Undergo Conformational Changes, Ugochi Isu

Graduate Theses and Dissertations

Proteins are not static entities; rather, they are dynamic macromolecules that undergo conformational changes to perform their biological functions. These structural transitions are often coupled to chemical events such as lipid interactions, or changes in the cellular environment. Understanding the intricate interplay between chemical perturbations and the resulting mechanical response is crucial for elucidating the activation mechanisms of proteins. This dissertation aims to characterize the role of chemo-mechanical couplings in the activation process of two G protein-coupled receptors (GPCRs): Cannabinoid Receptor 1 (CB1) and Metabotropic Glutamate Receptor 1 (mGluR1). We employ molecular dynamics simulations to investigate the conformational landscapes of …

Navigating Transitions: Utilizing Autoethnographic Writing Prompts To Support Nontraditional College Students, Brijet Lynn Beazer

Graduate Theses and Dissertations

This study explores the transition nontraditional students undergo as they embark on their college journey and the unique challenges they face. Leveraging autoethnographic writing prompts as an intervention strategy, the project employed a participatory approach over virtual platforms to capture the tapestry of experiences and connect participants to form a supportive community. Participants included older individuals with work experience, some who experienced parenthood, or those returning after an extended break. Through crafted prompts, individuals shared their academic journey, balancing work, and family responsibilities. The reflections gathered provide valuable data, offering insights into the challenges and triumphs of nontraditional students. The …

Understanding Video Modeling Adoption: Perspectives Of Special Education Teachers, Support Specialists And Transition Consultants, Hayot Tuychiev

Graduate Theses and Dissertations

This qualitative study investigates the knowledge, perceptions, and adoption factors of special education teachers and support specialists regarding video modeling (VM) as a vocational intervention for high school students with autism spectrum disorder (ASD). Grounded in Rogers' theory of innovation diffusion, the research explores their understanding of VM, its perceived effectiveness, and the factors influencing its adoption or rejection.This qualitative study investigates special education teachers' knowledge, perceptions, and adoption factors related to Video Modeling (VM) as a vocational intervention for high school students with autism spectrum disorder (ASD). Grounded in Rogers' theory of innovation diffusion, the research explores teachers' understanding …

Geochemical Analysis Of Basement Rock As A Potential Metal Source In Mississippi Valley-Type Ores, Southern Midcontinent U.S.A., Mackenzie Moorhead

Graduate Theses and Dissertations

Mississippi Valley-Type (MVT) ores are epigenetic, sedimentary hydrothermal base metal deposits that exist worldwide with type localities in the midcontinent United States. These Permian-aged sulfide ores represent an extraordinary concentration of economic metals, Pb and Zn. Ore deposits occur in vast districts that have a rich mining history. The Pb and Zn from these deposits account for 24% of worldwide reserves. The geologic processes responsible for MVT ore genesis are not fully understood, especially the sourcing of ore constituents. In the midcontinent, the Ouachita Orogeny expelled saline hydrothermal brines in response to high rates of subsidence. These fluids migrated through …

The Effects Of Instructed Task Prioritization On Dual-Task Cost In Older Adults, Megan D. Jones

Graduate Theses and Dissertations

Concurrently performing motor and cognitive tasks, also known as dual-tasking (DT), is a daily activity being shown to produce decrements in gait and cognitive performance in older adults (OA) (Bootsma-van der Wiel et al., 2003; CDC, 2023; Kenny et al., 2017). Determining if OAs can cognitively flex attention allocation between motor and cognitive tasks during DT activities offers insight into how to educate older adults on improving activities of daily life (Della Sala et al., 1995; Mac-Auliffe et al., 2021; Montero-Odasso et al., 2012). Purpose: To evaluate changes in DTC in older adults during DT walking with instructed task prioritization …

The Causes And Consequences Of Behavioral Plasticity In Anti-Predatory Defense And Mate Choice In Tropical Butterflies, Sushant Potdar

Graduate Theses and Dissertations

Behavioral plasticity, where individuals change their behaviors in response to varying environmental and social conditions, affects major evolutionary trajectories. But how individuals change these behaviors under certain social situations, and what the genetic causes and consequences of such behavioral changes are in response to social environments are yet to be fully understood. I address these questions in the context of anti-predatory behaviors (chapter 1), and mate choice (chapters 2, 3, 4) in tropical butterflies. In the context of anti-predatory behaviors, I found predator-specific behavioral changes in toxic Heliconius butterflies, suggesting variance in predation pressures and butterfly recognition of bird calls. …

Towards Side-Channel Infrastructure For Software Implementations Of Pqc Algorithms, Tristen Teague

Graduate Theses and Dissertations

Post-Quantum Cryptography (PQC) is a new class of asymmetric cryptography algorithms that are supposed to be secure against both classical computers and quantum computers through Shor’s algorithm. Since PQC algorithms are currently being standardized, they will replace older standardized asymmetric algorithms (such as RSA) and will be deployed within the digital infrastructure. Before implementations of the PQC algorithms are placed into the infrastructure, they must undergo evaluation of both performance and security. One such security issue that needs large investigation before deployment are side-channels. Side-channel attacks (SCA) are a method of gathering information from the implementation, such as power-consumption and …

Design And Implementation Of High-Frequency Dc-Dc Converters For Ev Applications, Rahul Biswash

Graduate Theses and Dissertations

The power electronics industry has been revolutionized by introducing wide bandgap semiconductor devices, such as Silicon Carbide (SiC) and Gallium Nitride (GaN). Due to their high frequency, high temperature, and high voltage operating capabilities, wide bandgap devices boast significant improvements in power density, efficiency, and reliability, as evidenced by their ability to decrease the size of power converters by operating at higher frequencies, temperatures and voltages, use of smaller and less passive components, such as transformers, inductors and capacitors, which makes power converters more compact and light-weight, ideal for space and weight-constrained applications, and compatibility with a wide range of …

Examining The Impact Of Parental Punishment And School Punishment On Delinquency And Criminal Justice Contact, Mia Robert

Graduate Theses and Dissertations

Prior research states the important role that both parents and schools play in setting children up for success. However, few researchers have studied how parents and schools work in tandem to achieve these outcomes. The current study aims to fill this gap by understanding the relationship between parental harshness and exclusionary discipline at age 9, specifically suspension, and how it affects delinquency and later criminal justice contact at age 15. Using longitudinal data from the Future of Families and Child Wellbeing Study (FFCWS), this study aimed to answer the following two research questions: 1) Does increased parental harshness and harsh …

Fabrication And Characterization Of Black Phosphorus Terahertz Photoconductive Antennae, Katie Michelle Welch

Graduate Theses and Dissertations

Advancements in terahertz (THz) imaging systems, particularly for applications like post-surgical analysis of breast cancer, have led to the exploration of novel materials such as black phosphorus as the active material for a THz photoconductive antenna (PCA). This thesis, motivated by innovative techniques developed at the University of Arkansas, investigates the potential of black phosphorus as a material to enhance the performance of THz PCAs, focusing on generation efficiency and bandwidth. Previous implementations of BP as THz emitters have shown limitations, highlighting the need for thorough material characterization and optimized fabrication processes. Therefore, we adopted a dual-phase approach to this …

Competition And Criticality In Cortical Neural Circuits Underlie Behavior And Optimize Working Memory, Jacob Harrison Barfield

Graduate Theses and Dissertations

One of the primary goals of neuroscience is to explain how brain function emerges from dynamic interactions among large populations of neurons. A long-standing hypothesis at the interface of physics and neuroscience posits that neural circuits may operate close to the critical point of a phase transition. In this dissertation, we will investigate a new form of criticality and the implications that it has in working memory and the generation of voluntary body movements. We will utilize this new form of criticality to investigate the functional benefits that can be harnessed by operating near the critical point when performing working …

Heterogenous Impacts Of Pathogenic Avian Diseases On Global Poultry Production, Elsbeth Hamilton

Graduate Theses and Dissertations

Globally, poultry is one of the most versatile and cost-effective sources of animal-based protein. Due to its wide variety of uses and variability of growing styles, poultry production is applicable in nearly every country. With the increase of scale and concentration of production, pathogenic diseases have decreased the efficiency of production through worsened feed conversion, morbidity, and mortality. In addition to physiological health, climate largely impacts the suitable conditions for growing. With more extreme climate events, locations once ideal for poultry are less efficient due to increased resource cost. This analysis seeks to determine the heterogeneity of production and the …

Exploring Diversity, Discrimination, And Performance Dynamics, George Agyeah

Graduate Theses and Dissertations

This dissertation utilizes empirical and experimental approaches to investigate the multifaceted factors that affect decision-making in economic contexts. The three chapters place a particular focus on group affiliation, perceived discrimination, and the gender gap in entrepreneurship. The first chapter explores the impact of team diversity on economic decision-making within a dynamic context. Through a series of laboratory experiments involving participants randomly assigned to teams, the study examines how team diversity influences individual behavior and performance. Results indicate that team diversity significantly affects individual behavior, with newcomers being particularly influenced by the diversity of the team they join. The findings underscore …

Guaraní Sexuality And Contestations Over The Old Way Of Being, Robert Miles Berry

Graduate Theses and Dissertations

The Jesuits in seventeenth century Guairá attempted to shift the sin of adultery and polygyny away from Guaraní men, and onto Guaraní women in their process of evangelization in Paraguay. The Jesuits did so because Guaraní men, as influential patriarchs within the missions, would revolt against the Jesuits or flee the Jesuit missions in response to Jesuit indoctrination that denounced the practice of polygyny. This is evident through two works of the Jesuit Antonio Ruiz de Montoya: one lexical, the Tesoro, and the other narrative, the Conquista. Montoya was directly involved in the founding and maintenance of the Guaraní missions, …

Determining The Climatic Effects Of The Central Atlantic Magmatic Province Across The End Triassic Mass Extinction In The Elliot Formation, Southern Africa, Danielle Elizabeth Oberg

Graduate Theses and Dissertations

Understanding the intricate relation between carbon-cycle perturbations, climate change, and biodiversity stability is crucial in the face of ongoing anthropogenic greenhouse-gas emissions. This thesis explores the impacts of rapid climate change induced by carbon-cycle perturbations and their potential repercussions on global climate. Large igneous provinces, particularly the Central Atlantic Magmatic Province, offer a lens through which to examine the nexus of volcanic activity, mass extinctions, and climate change. The emplacement of Central Atlantic Magmatic Province, covering vast regions across continents, emitted substantial amounts of carbon dioxide, profoundly impacting global climate and ecosystems. The end-Triassic Mass Extinction, attributed to Central Atlantic …

Two Studies: Aromatization-Driven Ring Opening Functionalization Of Unstrained Cycloalkanones Through Visible Light Catalysis, And Synthesis Of Amino Endoperoxides Using Self-Doped Titanium Dioxide (Ti3+@Tio2) As A Photocatalyst, Enoch Kudoahor

Graduate Theses and Dissertations

The pharmaceutical industry has been focused on discovering new innovative drugs over the last decade, but the syntheses are either inefficient or the approach to environmental sustainability raises significant concerns. Photochemistry and photocatalysis have found widespread applications in organic synthesis as a result of this pressing issue. Our role as organic chemists is to improve environmental quality by creating a "greener" world through the development of efficient synthetic methods and strategies. Solar energy is now one of the most abundant and renewable natural resources. The emergence of environmental sustainability concerns has led to the development of new techniques for harnessing …

Stillbirth Mortality By Robson Ten-Group Classification System: A Cross-Sectional Registry Of 80 663 Births From 16 Hospital In Sub-Saharan Africa, Claudia Hanson, Kristi Annerstedt, Maria Alsina, Muzdalfat Abeid, Hussein Kidanto, Helle Alvesson, Andrea Pembe, Peter Waiswa, Jean-Paul Dossou, Effie Chipeta

Centre of Excellence in Women and Child Health

Objective To assess stillbirth mortality by Robson ten-group classification and the usefulness of this approach for understanding trends.

Design Cross-sectional study.

Setting Prospectively collected perinatal e-registry data from 16 hospitals in Benin, Malawi, Tanzania and Uganda.

Population All women aged 13–49 years who gave birth to a live or stillborn baby weighting >1000 g between July 2021 and December 2022.

Methods We compared stillbirth risk by Robson ten-group classification, and across countries, and calculated proportional contributions to mortality.

Main outcome measures Stillbirth mortality, defined as antepartum and intrapartum stillbirths.

Results We included 80 663 babies born to 78 085 women; …

“I Want To Say The Right Thing”: Developing Translingual Literacy Practices Through Early Care Educator And University Researcher Partnerships, Angie Zapata, Mary Adu-Gyamfi, Adrianna González Ybarra

Bilingual and Literacy Studies Faculty Publications

An early care educator (ECE) and university collaborative model of teacher learning offers a distinct departure from common top-down models of professional development. Implementing a Social Design-Based Experiment, ECE and university partners collaborate to explore translingual picturebooks to address curricular inequities in their school settings. Featuring the experience of one white, middle-class ECE (Tamara) in a Midwest rural suburban school, we identify three critical components of this ECE and university researcher collaborative inquiry model: role of ECE as mentors and supporters, picturebooks as tools, and role of university partners as facilitators. Tamara’s experience highlights the critical components of the model, …

2024 Summer - Veterans Upward Bound Newsletter, Veterans Upward Bound, East Tennessee State University

Veterans Upward Bound Newsletters

No abstract provided.

Life On The Edge: The Cambrian Marine Realm And Oxygenation, Sara Pruss, Benjamin C. Gill

Geosciences: Faculty Publications

The beginning of the Phanerozoic saw two biological events that set the stage for all life that was to come: (a) the Cambrian Explosion (the appearance of most marine invertebrate phyla) and (b) the Great Ordovician Biodiversification Event (GOBE), the subsequent substantial accumulation of marine biodiversity. Here, we examine the current state of understanding of marine environments and ecosystems from the late Ediacaran through the Early Ordovician, which spans this biologically important interval. Through a compilation and review of the existing geochemical, mineralogical, sedimentological, and fossil records, we argue that this interval was one of sustained low and variable marine …

Assessing Teachers’ Dispositions Towards Culturally Responsive Pedagogy In Northwest Arkansas High Schools, Rylie Ford

Curriculum and Instruction Undergraduate Honors Theses

Culturally responsive pedagogy (CRP) entails the use of cultural knowledge, prior experiences, and learning styles of ethnically and culturally diverse students to make instruction more relevant and effective for them. Furthermore, practices within this pedagogy are validating, inclusive, emancipatory, and ethical, and help diverse students succeed academically while maintaining their cultural identity. Numerous studies have indicated that using culturally responsive pedagogy increases student academic achievement, sense of self, and emotional well-being (Ladson, 1995; Gay, 2018). Considering the varying degrees of cultural and linguistic diversity in Northwest Arkansas (NWA) schools and the lack of reported professional development relating to CRP, this …