Digital Commons Network^™

Greek Key-Inspired Fractal Metamaterials With Enhanced Flexibility And Energy Absorption., Zhennan Zhang

Electronic Theses and Dissertations

Architected materials with intricate three-dimensional (3D) geometries offer unique properties and functionalities but face challenges in manufacturing costs and complexity. This research explores the integration of simple 2D Greek Key-inspired lattices into fractal designs to achieve exceptional mechanical performance. Using 3D printing and kerfing, these fractal structures demonstrate enhanced flexibility and energy absorption capabilities. Through three-point bending and in-plane tensile tests, the 2D fractal lattices exhibited a 600-fold reduction in bending force and a tensile stretch capacity of up to 520%, significantly outperforming brittle parent materials. Out-of-plane compression tests revealed a five-fold increase in energy absorption compared to honeycomb structures, …

Nickel Electrocatalysts On Carbon Supports For The Hydrogen Evolution Reaction., Mohan Paudel

Electronic Theses and Dissertations

Hydrogen is an important energy storage alternative to fossil fuels due to its high energy density. Currently, most hydrogen is produced through petroleum feedstocks, which produce large amounts of carbon dioxide. However, a more eco-friendly method is the electrocatalytic splitting of water into hydrogen and oxygen. Efficient catalysts for the hydrogen evolution reaction (HER) are typically platinum group metals, which are rare and expensive. There is growing interest in developing HER electrocatalysts with earth-abundant metals for water electrolysis. Nickel, which lies in the same group in the periodic table as Pt and has similar chemical properties, is explored extensively for …

Elevator Music., Lillian Caroline Reed

Electronic Theses and Dissertations

A spy, doctor, engineer, and businessman find themselves trapped in a malfunctioning elevator in a contemporary, humorous take on Sartre's No Exit. Are these four, who come to despise each other, gathered here by chance? Is this eternal elevator ride some sort of divine punishment?

Is this hell?

Victims Unknown: An Evaluation Of The Way Louisville, Kentucky Communicated About Aids At The End Of The 20th Century, Alexander M. Vernon

Electronic Theses and Dissertations

This is thesis examines the way that printed news sources reported on AIDS during the height of the epidemic in Louisville, Kentucky. It compares between mainstream and grass-roots sources to work to identify shortcomings in reporting, and how reporting on a public health crisis can be improved upon in the future. It uses an intersectional framework to deconstruct why certain news sources reported on specific demographics of the population, across racialized and gendered lines. Chapter One analyzes the epidemic and then contextualizes the language that was used. Chapter Two focuses on mainstream local newspapers, while also defining demographics of AIDS …

Understanding Defect Dynamics In Black Phosphorene Under Noble Gas Ion Irradiation., Saransh Gupta

Electronic Theses and Dissertations

Controlled introduction of defects in phosphorene using high-energy ion beams offers a promising route to design novel high-performance materials for energy technologies. However, this potential remains underexplored due to a lack of fundamental understanding of the atomic-scale mechanisms governing the production, accumulation, and temporal evolution of defects during ion irradiation. Here, we employ a combination of classical and ab initio molecular dynamics simulations to elucidate the effects of ion energy, angle of incidence, noble gas ion size/mass, and fluence on (a) defect generation (i.e., point defects, topological imperfections, voids), (b) atomic-scale mechanisms of defect formation and re-arrangement, and (c) defect …

21st Century Community Learning Centers: Program Evaluation Evidence From Texas, Rosilyn Jackson

Electronic Theses and Dissertations

Texas afterschool programs strive to enhance academic performance and meet students' needs, yet gaps in program quality persist. This study evaluated 21st Century Community Learning Centers’ performance in reading, math, GPA, attendance, in-school suspension, and engagement, both within these categories and against program goals and demographics. Theoretical frameworks used in this study include the logic model, social justice theory, and cultural relevance theory. This quantitative study utilized a nonexperimental and secondary data research design which utilized five statistical tests: the Pearson Product-Moment Correlation, One-Way repeated ANOVA, Spearman Correlation, the Independent Samples t-Test, and the Mann-Whitney U Test. Results showed that …

Detecting Anomalies In Dynamic Attributed Graphs: An Unsupervised Learning Approach, Austin Hamilton

Electronic Theses and Dissertations

Dynamic attributed graphs, which evolve over time and hold node-specific attributes, are essential in fields like social network analysis, where anomalous node detection is a growing area. Vehicular social networks (VSNs), a subset of these graphs, are ad hoc networks in which vehicles exchange data with one another and with infrastructure. In this dynamic context, identifying anomalous nodes is challenging but crucial for maintaining trust within the network. This work presents an unsupervised deep learning approach for anomalous node detection in VSNs. This model achieved an accuracy of 71% while detecting synthetic anomalies in a simulated network based on real-world …

An Exploration Of K-3 Teachers’ Beliefs, Attitudes, And Instructional Technology Use Pre-, During, And Post-Covid-19, Patience Mensah-Bonsu Aggrey

Electronic Theses and Dissertations

This qualitative multiple case study explores kindergarten to third-grade teachers use of instructional technology across three different periods: pre-COVID-19, during COVID-19, and post-COVID-19. This research investigates teachers’ attitudes, the use of technological tools by teachers, and the internal (second order) and external (first order) barriers that informed their use of instructional technology before and during the COVID-19 pandemic and continue to influence their use in the post-pandemic phase. Data were collected through questionnaires, interviews, and checklists from eight kindergarten third-grade teachers using a qualitative multiple case study approach. The findings suggest that there was a shift in teachers’ instructional technology …

Unraveling Phytosulfokine Trafficking In Arabidopsis Thaliana Using Fiber-Optic Fluorescence Microscopy, Issaka Obuaba

Electronic Theses and Dissertations

As sessile organisms, plants manage stress through complex signaling networks involving phytohormones such as phytosulfokine (PSK). PSK, a disulfated pentapeptide, regulates plant growth, development, and stress responses by interacting with specific PSK receptors (PSKRs). In this study, we explored the trafficking dynamics of PSK, its post-application fate, and the synthesis of an analog. We administered both native PSK and a fluorescent version tagged with TAMRA (5(6)-carboxytetramethylrhodamine) to various Arabidopsis thaliana genotypes, including wild type, a PSKR-deficient mutant, and a strain overexpressing PSKR1 tagged with green fluorescent protein (GFP) over the wild-type background. Fiber-optic fluorescence microscopy revealed that receptor presence influences …

Digital Storytelling Strategies For Viewer Engagement: A Rhetorical Analysis Of Youtube Videos By Nonprofit Healthcare Organizations, Maame Aba Afful

Electronic Theses and Dissertations

As reliance on digital media and social media platforms such as YouTube increases, health organizations infuse rhetorical strategies to create memorable and impactful health-related videos to raise awareness and attract support. Nonprofit healthcare organizations use digital storytelling to communicate their impact. In this study, I conduct a rhetorical analysis of five digital storytelling videos shared on the YouTube pages of nonprofit healthcare organizations to: identify how the videos leverage rhetorical appeals, point-of-view (POV), and metadata; and discuss how such strategies might influence viewer engagement or brand objectives. My findings suggest that nonprofit healthcare organizations integrate positive and negative emotional appeals …

Investigating Phytosulfokine Trafficking: Insights Into The Role Of Phytohormones In Plant Signaling, Martin Tindi

Electronic Theses and Dissertations

Phytosulfokine is a critical signaling peptide involved in plant growth, development, and stress responses. This thesis investigates the trafficking mechanisms of Phytosulfokine (PSK) in Arabidopsis thaliana, employing fluorescently labelled PSK for non-destructive imaging using a custom-built fiber-optic fluorescence microscope. The study aims to determine the mobility and fate of PSK in plant tissues. Experimental results reveal the short-range and long-range movement of PSK across leaves. Additionally, the project highlights the optimization of non-destructive imaging techniques and the synthesis of caged dexamethasone to facilitate optogenetic studies. These findings provide new insights into PSK trafficking mechanisms in plants, enhancing our understanding …

Service Provider Perceptions Of Systems Serving Individuals Experiencing Homelessness: A Needs Assessment And Strategic Plan In Johnson City, Tn, Opal Frye-Clark

Electronic Theses and Dissertations

This Integrated Learning Experience (ILE) investigates service providers' perceptions of Johnson City, Tennessee's homelessness services, aiming to inform a city-wide strategic plan for reduction. Employing a mixed-methods approach, the study gathered qualitative data through in-depth interviews with service providers in 2022 and quantitative data via a 2024 survey. The research focused on those directly involved in serving or significantly influencing the lives of individuals experiencing homelessness (IEH). Three key aims guided the investigation: (1) To analyze provider perspectives to identify community assets, opportunities, barriers, and unmet needs, informing a comprehensive needs assessment; (2) To refine these findings through SWOT analysis …

East Texas Master Gardener Characteristics, Volunteer Choices, And Willingness To Answer Questions From The Public, Damon Gregory Grant

Electronic Theses and Dissertations

East Texas Master Gardener volunteers were asked to participate in an exploratory Qualtrics survey during the fall of 2023. This study examined the demographic characteristics, volunteer engagement choices, and challenges of Master Gardener volunteers in Texas A&M AgriLife Extension Service District 5, focusing on whether current training adequately prepares volunteers for public-facing roles. Findings showed that volunteers were primarily older, retired, well-educated, white females, favoring hands-on activities like garden demonstrations and fundraising over Help Desk question answering roles due to perceived inadequacies in knowledge. Over 80% indicated that mentorship and advanced training could improve their confidence in public interactions. Recommendations …

Soundscapes Of The Pillow Book: Creating Music Exploring Pamela Z'S Sonic Landscapes, Asuka Kakitani

Electronic Theses and Dissertations

Pamela Z stands as a pioneering force in contemporary music, seamlessly integrating her roles as a composer, performer, and media artist. Renowned for her innovative approach, she masterfully combines her voice with live electronic processing, sampled sounds, and video elements, crafting a distinctive musical landscape that embodies the forefront of artistic exploration in our time. The primary aim of this thesis is to create “The Pillow Book,” a new musical work inspired by Z's creative process and methods. This work will also incorporate elements of my native language and ancient Japanese text from The Pillow Book, written in 1002 …

Bioremediation Of Effluent Water In A Coal Ash Disposal Area: Optimizing Microbial Sulfate Reduction, Ryka Shea

Electronic Theses and Dissertations

Coal combustion residues (CCR) pose a serious environmental threat, even long after they are disposed of in specialized landfills, due to their complex composition and potential for leaching into waterways. This study focuses on the issue of elevated sulfate concentrations at the Martin Lake Steam Electric Station (MLSES) A-I Disposal Area in Panola County, Texas, where CCR are disposed of in a permanent landfill. Currently, this site is exceeding its regulatory limit of sulfate concentrations in its effluent and is in need of a cost-effective and sustainable solution to this problem. This research utilized benchtop experiments to investigate sulfate reducing …

Graduation Rates Of Students With Disabilities At A Participating Southern University, Kelly Mitchell

Electronic Theses and Dissertations

The purpose of this non-experimental, correlational quantitative study was to compare the graduation rates of first-time, full-time students with disabilities to those of first-time, full-time students in the general population at the participating university. The sample used for analysis was full-time, first-time students entering between 2015 and 2020. Using archival data from the Disability Services database and the University's Banner system, four- and six-year graduation rates were compared. The original data set consisted of 22,070 students in the starting focus cohorts. After removing entering transfer students and students who enrolled in less than 15 credits for their entering semester, 8,337 …

Landslide Inventory And Unstable Slope Monitoring Along Highways In Eastern Tennessee, Robert Mcsweeney

Electronic Theses and Dissertations

This research introduces an unstable slope management program (USMP) for Tennessee based on federal slope management standards, along with improved methods for landslide monitoring with unmanned aerial systems (UAS) lidar and photogrammetry. In mountainous regions, monitoring slope hazards is a critical function of transportation management. A mobile field assessment form created with Survey123 was used to collect 22 unstable slope ratings in eastern Tennessee. Location points were appended with photographs, notes, and site information. Landslide scores ranged from 325 (Fair) to 1005 (Poor). UAS monitoring of a slow-moving soil landslide along I-40 near Rockwood, TN, produced high-resolution lidar and photogrammetry …

The Lived Experiences Of Women In Construction: Career Supporting Strategies, Cheryl Anne Loar Croall

Electronic Theses and Dissertations

Women are underrepresented in the United States construction industry, representing only 11% of the workforce, and this lack of diversity in the male-dominated occupation results in barriers to female career advancement. The problem is that women in construction experience obstacles to career progression due to gender work life balance, sexual harassment, and pay inequality; barriers such as these keep women out of leadership roles. Three recommended techniques to support women’s career progression in construction and combat barriers to career advancement include social support, fighting back (openly challenging discrimination), and positive reappraisal (reframing negatives to positives). Understanding the effectiveness of these …

Nonacademic Factors That Effect Early College High School Student's Resilency, Amy Draper

Electronic Theses and Dissertations

This qualitative descriptive study was an exploration of how counselors in early college high

schools (ECHSs), administrators in ECHSs, and the technical coaches who support the ECHS

model contribute to students’ resilience toward academic recovery. Using semistructured

interviews and survey questions, a sample of 15 counselors, administrators, and technical

coaches shared factors that impact ECHS recruiting practices, attrition rates, and the educational

success of individual ECHS students. Three themes were extracted from a sample of educators’

descriptions regarding their perception of the ECHS environment and the benefits and challenges

they experienced while working with ECHS students. They included the combined …

Exploratory Learning In Two Modalities: Tabular Vs Graphical., Lianda Velic

Electronic Theses and Dissertations

In traditional educational settings, an instructor delivers a lecture prior to providing students a practice activity. Exploratory learning reverses this order to encourage active learning and engagement, typically improving learning outcomes. However, more research is needed in order to determine how to optimally design exploratory learning materials, and how differences in such design impact learning processes and outcomes. The current study investigated the impact of instructional order and activity modality type (tabular or graphical) on learning outcomes. Undergraduate students (N=252) were taught the statistical concept of consistency and the formula to compute standard deviation. In the instruct-first condition, …

A Little Bit Of Everything: Persistence Though The Pre-Medical Pipeline For First And Continuing Generation Students., Tana R. Didelot

Electronic Theses and Dissertations

This qualitative research study examines pre-medical college student persistence in their pathway to medical education. Through the framework of Terenzini and Reason’s College Student Persistence Model (2005), this work sought to understand the pre-college experiences, campus support factors, and external environments that help pre-medical college students to continue toward their goal of medical school entry. This study included pre-medical undergraduate students in the campus context of one public institution in the Southern Unites States. Pre-medical upperclassmen students were interviewed using a semi-structured protocol developed with the persistence framework. The analysis was conducted to obtain a more nuanced understanding of the …

Development Of A Square Wave Voltage Field-Oriented Controller For A Linear Vapor Compressor., Thomas Everson

Electronic Theses and Dissertations

In this thesis, a novel control strategy for an inverter-driven linear compressor system is proposed in which the overall electrical losses of a coupled inverter-linear motor system are reduced through the use of a modified square wave inverter modulation scheme to minimize inverter switching losses at the expense of a modest increase in conduction losses. The controller is based on a single-phase field-oriented control strategy, and to achieve the FOC control objectives, the fundamental and dc components of the applied square wave voltage are matched to the corresponding values requested by the current controller. To validate the efficiency improvements offered …

Ai-Driven Approach For Diagnosis Of Renal Transplant Rejection Based On Biomarkers Identification And Integration., Israa Sharaby

Electronic Theses and Dissertations

They kidney is a vital organ for which humans are fortunate to find a spare through transplantation to sustain critical body functions, offering a hope to those struggling with renal failure. Kidney transplant procedure is the optimal treatment for people who suffer from end-stage renal failure. However, there are posed challenges due to the risk of immune rejection and the limited availability of donors. Early detection of renal rejection can provide timely intervention and accurate diagnosis that are critical to improve the transplant outcomes. This study explores the innovative approaches for addressing the current challenges through biomarkers identification, imaging techniques, …

Modeling And Understanding Of Additive Manufacturing Periodic Cellular Structures With Heterogeneity: Property, Quality And Design Strategy., Naresh Koju

Electronic Theses and Dissertations

Lightweight cellular structures with their higher per mass performance capability, multifunctional designability and property tolerability are gaining much wider adaptation in many engineering applications ranging from aerospace, defense, biomedical, automotive to sports. However, to achieve the desired performance levels careful design must be carried out. The experimental-based empirical design often involves high manufacturing cost, and there are also certain information/knowledges about the cellular deigns that could not be easily obtained experimentally, such as the deformation local fracture initiation. Similarly, numerical modeling-based design approach commonly suffers from high computation cost and the lack of inverse designability. In addition, numerical models often …

Toward An Urban Food Commons: Participatory Action Research On Food Apartheid And Community-Based Agrifood System Governance In Louisville, Ky., Mary Abigail Rudolph

Electronic Theses and Dissertations

This dissertation investigates the structural inequities fueling food apartheid in Louisville, Kentucky’s agrifood system and explores community-based governance as a path toward food justice. Through a participatory action research (PAR) framework, this study combines participatory geographic information systems (PGIS), focus groups, and autoethnography to engage directly with affected community members and collaborate with the Food in Neighborhoods (FIN) coalition. By prioritizing the voices of those most impacted by food insecurity, this research offers contributions to the fields of food justice, participatory governance, and urban food commons. The study situates Louisville’s food access issues within the broader neoliberal global agrifood system, …

My Superpower: Research Collaborator Strategies Among Faculty Members Who Are First-Generation College Graduates, Faye Farmer

Electronic Theses and Dissertations

This inductive study examined the intersectional experience within research collaborations of tenure-track faculty who are both first-generation college graduate students and from racial and ethnic groups (as defined in the United States) that are underrepresented in STEM fields (as defined by the National Science Foundation). I interviewed twelve current and former faculty members from doctoral-granting universities in the United States. I used identity as the theoretical lens to explore research collaborations at the individual level. The interviews revealed three themes reflecting identity's role in selecting and being selected as a collaborator and working with a collaborator. The themes are: an …

Designing Customized Loss Functions For Training Deep Neural Networks, Ali Pourramezan Fard

Electronic Theses and Dissertations

This dissertation explores the critical role of loss functions in enhancing the predictive performance of deep machine learning models. Loss functions are an integral element of all the ongoing advances we witness daily in this domain. I design custom loss functions and their impacts on various machine learning tasks, particularly in computer vision.

In the first stage of my research, I aim to improve the prediction performance of deep learning models by providing them with more precise feedback associated with task requirements. This led me to create the concept of assistive loss functions. My first proposed loss function, inspired by …

We’Re Not In Texas Anymore: Archaeological Investigations In Historic Dallas, Colorado, Tristan Newberry-Cushman

Electronic Theses and Dissertations

This work is the product of an archaeological investigation of the former townsite of Dallas, Colorado. Archival research, drone photography, shovel test pits (STPs), and a test excavation unit were employed to learn more about how the people of Dallas lived, and how they interacted with national systems. Probabilistic and purposive sampling were used to collect data, and both quantitative and qualitative analysis were performed. The goal of this research was to determine which theoretical model best explains how Dallas was connected to national cultural and economic systems.

The Impact Of Cumulative And Acute Loading On Achilles Tendon Health, Performance, And Reported Pain In Collegiate Gymnasts, Julio Serrano Samayoa

Electronic Theses and Dissertations

Gymnasts are at a high risk of Achilles tendon (AT) injuries due to intense loads during takeoffs and landings. To better understand better the relationship between impact loading and its effects on tendon adaptation and athletic performance, this study uses Inertial Measurement Units (IMUs) to track AT loading across a collegiate gymnastics season. This data were compared against physiological and athletic performance metrics, obtained through force plates and ultrasound imaging, to explore how mechanical load influences reported pain and athletic performance. Results varied, with cumulative impacts being correlated with improved jump height (Spearman 0.362, Pearson 0.348), while peak power and …

Model-Based Navigation And Control Of Multirotor Uavs: A Machine Learning Approach, Serhat Sönmez

Electronic Theses and Dissertations

In recent decades, unmanned systems, particularly Unmanned Aerial Vehicles (UAVs), have seen significant advancement and unprecedented growth in military, civilian and public domain applications. Scientists have focused on enhancing UAV navigation and control through cutting-edge technologies and support tools. UAVs find applications in many fields, except military, such as agriculture, infrastructure inspection, wildlife monitoring, search and rescue, emergency response, border protection, to name but a few relevant civilian applications. Given the faster-than-exponential increase of available computational power, learning-based algorithms have emerged as a prominent tool for (real-time) multirotor UAV navigation and control. This dissertation centers around the fusion of conventional …