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Fabrication And Characterization Of Black Phosphorus Terahertz Photoconductive Antennae, Katie Michelle Welch May 2024

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 May 2024

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 …


The Water That Will Be: A Qualitative Look Into The Effects Of Visual Imagery On Participation In Water Conservation Initiatives, Shane Martin White May 2024

The Water That Will Be: A Qualitative Look Into The Effects Of Visual Imagery On Participation In Water Conservation Initiatives, Shane Martin White

Graduate Theses and Dissertations

This dissertation explored the role of visual imagery in water conservation initiatives, focusing on its impact on public understanding, emotional connection, and willingness to participate. Drawing from the Theory of Planned Behavior and Affective Disposition Theory, the study investigated how art interventions can enhance comprehension and engagement with water conservation easements. Utilizing qualitative methods, including interviews, focus groups and PhotoVoice, data was collected from stakeholders in the Illinois River Watershed region. The research examined current levels of understanding regarding conservation easements, evaluated the effectiveness of visual imagery interventions in enhancing public awareness, and identified the potential for collaborative approaches between …


Evaluation Of Protein Turnover, Lipid Turnover, And Calcium Utilization On Broiler Breeder Performance, Cole Umberson May 2024

Evaluation Of Protein Turnover, Lipid Turnover, And Calcium Utilization On Broiler Breeder Performance, Cole Umberson

Graduate Theses and Dissertations

Broiler breeder performance is based upon egg production. Breeders are reared from day of hatch to ovulation with the main goal of controlling body weight. Maintaining body weight in breeders is highly emphasized prior to first egg as to reach optimum peak production feeding increases dramatically to meet energy needs. Energy is supplied to the breeder in three forms carbohydrates (fast energy), protein (medium energy), and fat (slow energy). Carbohydrates are quickly used by the breeders, while protein is constantly being utilized by the breeder for growth and egg production, fat is stored and used lastly as the energy requirements …


Exploring Diversity, Discrimination, And Performance Dynamics, George Agyeah May 2024

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 …


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 May 2024

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 May 2024

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 …


Generalizations Of The Hardy Spaces And The Schwarz Boundary Value Problem, William L. Blair May 2024

Generalizations Of The Hardy Spaces And The Schwarz Boundary Value Problem, William L. Blair

Graduate Theses and Dissertations

We prove that many of the boundary properties associated with functions in the classic holomorphic Hardy spaces on the complex unit disk are present in Hardy classes of solutions to certain nonhomogeneous Cauchy-Riemann equations and higher-order generalizations of these equations. Also, we explicitly solve generalizations of the Schwarz boundary value problem on the complex unit disk and the upper-half plane when the boundary condition is in terms of boundary values in the sense of distributions.


Dyslexia Training: The Impact On The Perceptions And Knowledge-Base Of Pre-Professionals Preparing To Work In K-12 Educational Settings, Colby Fowler May 2024

Dyslexia Training: The Impact On The Perceptions And Knowledge-Base Of Pre-Professionals Preparing To Work In K-12 Educational Settings, Colby Fowler

Graduate Theses and Dissertations

This research explores the perceptions and understanding of dyslexia among first-year graduate students in speech-language pathology. Employing survey methodology, specifically a pre- and post-survey approach, this research investigates the attitudes and knowledge that the participants have in understanding and addressing dyslexia at the beginning of their graduate training. The study seeks to uncover the existing awareness, potential misconceptions, and the overall preparedness of these emerging professionals in dealing with individuals affected by dyslexia. Through a comprehensive survey analysis, the research aims to contribute valuable insights that can inform the development of targeted educational strategies and interventions within speech-language pathology programs, …


Geomorphic Analysis Of The Lower Arkansas River, Usa, Matthew Edwards May 2024

Geomorphic Analysis Of The Lower Arkansas River, Usa, Matthew Edwards

Graduate Theses and Dissertations

The Arkansas River is one of several large and important river systems stretching from the Rocky Mountains to the Mississippi River. It meanders across the Great Plains for ~1000 km before plunging into a mountain-bound valley, confined by the Ozarks to the north and Ouachitas to the south. The geologic history of the Arkansas River is poorly understood and crudely constrained to sometime between ~60 Ma and 100 Ka. Questions remain concerning its path(s), potential integration of the upper and lower sections, and overall history. The combination of knickpoint and chi (χ) mapping, tributary grain size analysis, tensile strength testing, …


Affinity-Enhanced Microdialysis Using Covalent Organic Frameworks (Cofs) Applied To Various Non-Steroidal Anti-Inflammatory Drugs (Nsaids) And Their Metabolites, Kehinde Adedeji Olubanjo May 2024

Affinity-Enhanced Microdialysis Using Covalent Organic Frameworks (Cofs) Applied To Various Non-Steroidal Anti-Inflammatory Drugs (Nsaids) And Their Metabolites, Kehinde Adedeji Olubanjo

Graduate Theses and Dissertations

Microdialysis is a valuable tool in neurosciences and pharmaceutical sciences, aiding research in drug-related areas. However, it faces a notable limitation in sampling hydrophobic analytes due to their adherence to the probe materials brought about by non-specific adsorption, thereby reducing relative recovery or overall extraction. In this work, two affinity agents, polydimethylsiloxane (PDMS) beads suspended in sodium dodecyl sulfate (SDS) surfactant and covalent organic frameworks I(COFs) were employed as affinity agents in microdialysis for the extraction of hydrophobic drugs. When PDMS beads were employed as affinity agents, at the flow rate of 1 µL/min the relative recovery of both the …


High-Power Dc-Dc Transformer For Medium-Voltage Grids With High-Voltage Sic Technology, Roderick Gomez May 2024

High-Power Dc-Dc Transformer For Medium-Voltage Grids With High-Voltage Sic Technology, Roderick Gomez

Graduate Theses and Dissertations

The objective of this dissertation is to present the theoretical analysis, design process, application and manufacturing of a proposed solid-state transformer intended for medium-voltage applications with minimal high-frequency oscillations. Galvanic isolation on medium-voltage DC-DC converters tend to employ large number of turns in the high voltage side of the transformers leading to non-negligible parasitic stray capacitances which form resonance tanks with the transformer inductances. Therefore, it is critical to estimate these parasitic capacitances to avoid severe high frequency oscillations which can significantly impact the converter performance. The main contribution of this thesis is the extension of a proposed custom-core design …


Guided Pathways: How Early Major Declaration Impacts Student Graduation Rates, Chris Mcbeath May 2024

Guided Pathways: How Early Major Declaration Impacts Student Graduation Rates, Chris Mcbeath

Graduate Theses and Dissertations

Increasing graduation rates continues to be a high priority for administrators at community colleges nationwide. While several factors affect graduation rates, many researchers focus on how a student’s status as declared or undecided may impact their likelihood of graduating. This study aims to examine the potential relationship between matriculating with or without a major declared and degree completion. There exists a perception that an early decision about a major is a critical step in ensuring students graduate. Many institutions require or strongly encourage students to declare a major before enrolling in their first semester. Previous research about undeclared students and …


Erased From The Curriculum: Studying The Role Curriculum Plays On Students Political Attitudes At The University, Julie Jann Gallagher May 2024

Erased From The Curriculum: Studying The Role Curriculum Plays On Students Political Attitudes At The University, Julie Jann Gallagher

Graduate Theses and Dissertations

University curriculum shapes political identity. Most studies focus on secondary education, overlooking the influence of university curriculum and its effect on students’ political attitudes. For this study, I examine the curriculum of three classes: American Government, African American Studies, and Astronomy. I argue that exposure to race-specific curriculum shapes racial identity. The results will suggest that students who take non-race-specific courses are more likely to support racially neutral and colorblind (White Nationalist) attitudes. I argue that curriculum affects students’ political attitudes.


Heterogenous Impacts Of Pathogenic Avian Diseases On Global Poultry Production, Elsbeth Hamilton May 2024

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 …


Yeast Surface Display Of Multiple Heterologous Proteins Via Molecular And Biochemical Processing Techniques, Shadrach Ibinola May 2024

Yeast Surface Display Of Multiple Heterologous Proteins Via Molecular And Biochemical Processing Techniques, Shadrach Ibinola

Graduate Theses and Dissertations

The arming of yeast cell wall, also known as yeast surface display, is an effective technology for expressing target proteins extracellularly. It has been shown to provide bioengineered yeast with qualities that are not known to native yeast such as the ability to survive harsh conditions including high pH and temperature, for example. Furthermore, this technique has been implemented for various applications which include, protein engineering, bioethanol production, bioremediation, vaccine construction, and antibody development. The major mechanisms of yeast surface display exploit agglutination, flocculation, or proteins with internal repeats as the means by which a target (protein) is covalently attached …


In-Service Needs Of Selected Arkansas Agriculture Teachers Related To Precision Agriculture Systems, Henry Ofosu Akwah May 2024

In-Service Needs Of Selected Arkansas Agriculture Teachers Related To Precision Agriculture Systems, Henry Ofosu Akwah

Graduate Theses and Dissertations

Precision Agriculture (PA) entails the use of computer technology, including software and hardware, together with good agronomic practices to effectively utilize resources available to growers. PA may enhance profitability, sustainability, resilience, and efficiency when implemented successfully. The aim of this study was to identify, assess, and describe the PA in-service needs of selected high school agriculture teachers in Arkansas. Forty-four teachers participated in the study, recruited through convenience sampling during the annual Arkansas agriculture in-service workshop held at Camp Couchdale in July 2023. A survey instrument was developed, and all forty-four participants provided complete responses. The survey included twenty-nine PA …


More Than A Monolith: Three Essays On The Diverse Journey Of Immigrant Students And Their Postsecondary Outcomes, Rian Rinaldi Djita May 2024

More Than A Monolith: Three Essays On The Diverse Journey Of Immigrant Students And Their Postsecondary Outcomes, Rian Rinaldi Djita

Graduate Theses and Dissertations

For many years, the United States (U.S.) has been the country with the largest number of immigrants. As a result, policy about immigrant students’ success becomes crucial since it carries not only ethical implications but also economic and societal implications. While there have been other alternatives for students’ success, such as Career and Technical Education (CTE), undeniably, college is still seen as a common pathway to success (e.g., Choi, 2015; Heckman et al., 2018; Turner, 2004). Unfortunately, there are several gaps in the literature on immigrant students’ success and postsecondary outcomes. First, while there is an increasing number of immigrants …


Temporal Trends And Dental Metric Variation In The Macaca Sylvanus Lineage, Cristina Stan May 2024

Temporal Trends And Dental Metric Variation In The Macaca Sylvanus Lineage, Cristina Stan

Graduate Theses and Dissertations

The extensive collection of fossil macaques from Europe, spanning from the Late Miocene to the Late Pleistocene period, is believed to be of the species Macaca sylvanus. However, there has been a prolonged discussion regarding the classification of these specimens into a single taxonomic group as the existing dental sample exhibits a large amount of morphological and metric variation. Specifically, researchers have attempted to identify multiple subspecies based on chronological data of the paleontological locality and, secondly, based on dental metric variation. In this study, I assess temporal trends in the fossil record of Macaca sylvanus and compare overall variation …


Advancing Qualitative Inquiry In Agricultural Communications: An Analysis Of Theories, Methodologies, And Standards For Quality, Karli Yarber May 2024

Advancing Qualitative Inquiry In Agricultural Communications: An Analysis Of Theories, Methodologies, And Standards For Quality, Karli Yarber

Graduate Theses and Dissertations

This dissertation offers a deep dive into the evolving landscape of qualitative research within the field of agricultural communications. Through a trio of research articles, this research critically assesses the application of theories, methodologies, and standards for quality across studies published in six disciplinary journals from 2003 to 2023. The first manuscript explores the theoretical frameworks guiding qualitative research in agricultural communications, uncovering a diverse but scattered theoretical underpinning with Framing, Diffusion of Innovations, and Uses and Gratifications Theory emerging as the most prevalent. The second manuscript meticulously examines the methodologies employed, revealing a growing acceptance and application of qualitative …


Automatic Appraisals Of Houses, Sloan Scroggin May 2024

Automatic Appraisals Of Houses, Sloan Scroggin

Graduate Theses and Dissertations

Multiple hedonic models and an automatic appraiser model were used to create a residential house’s estimated sales price. The goal is to use the limited data available to a REALTOR® to estimate the future sales price of a residential home without the aid of pictures of the property or viewing the physical property. The first model automates some of the actions of an appraiser by finding comparable sales based on proximity, based both on distance between houses and characteristics of the houses, and then calculating a weighted average price for an estimated sales price of future sales. If the model …


Two-Photon Quantum Gates With Single Atoms, Arkan Mahmood Hassan May 2024

Two-Photon Quantum Gates With Single Atoms, Arkan Mahmood Hassan

Graduate Theses and Dissertations

In the first part of this dissertation we study in detail the interaction of single-photon and two-photon wavepackets with a three-level V-type atom in a cavity without any control over the interaction time. We solve analytically for the spectrum of the outgoing wavepackets as a function of the incident wavepacket that is valid in all the cavity limits. We consider the potential performance of this system as a CPHASE gate by considering several special input pulses. We optimize for the gate fidelity and find values of the cavity, atomic and pulse parameters that yield a conditional phase shift of π, …


Key Practices In P-6 Integrated Stem Education: A Delphi Panel Investigation, Leah R. Cheek May 2024

Key Practices In P-6 Integrated Stem Education: A Delphi Panel Investigation, Leah R. Cheek

Graduate Theses and Dissertations

Throughout the past two decades policymakers, practitioners and researchers have been summoned to pursue best practices to address and implement improvements in STEM education for P-12 students (Archer, Moote, MacLeod, Francis, & DeWitt, 2020; Emrey-Arras, 2018; Hodson, 2003; National Research Council, 2012). Irrespective of the longstanding investment of time and resources towards STEM education, students’ patterns of STEM involvement in schools continue to be persistently unchanged (Archer, et al., 2020; Ro & Knight, 2016) and even fewer Americans are entering STEM disciplines in the workforce (National Science Foundation, 2018). The purpose of this three-article dissertation study is to support effective …


Hardware Trojan Detection Utilizing Graph Neural Networks And Structural Checking, Hunter Nauman May 2024

Hardware Trojan Detection Utilizing Graph Neural Networks And Structural Checking, Hunter Nauman

Graduate Theses and Dissertations

The integrated circuit (IC) industry has experienced exponential growth, particularly in the complexity and scale of hardware designs. To sustain this growth, faster development cycles and cost-effective solutions have been the focus for many companies. One strategy to maintain this growth is through the incorporation of third-party intellectual property (IP) into the IC design process. Outsourcing the production of sub-components reduces development time and enables faster time-to-market, however, this approach also introduces the threat of Hardware Trojans. Hardware Trojans, defined as any malicious modification or addition to an IC, pose significant security risks due to their small size, low activation …


Investigate The Importance Of Local Magnetic Moment And Magnetic Interaction In Superconducting Fese Monolayer Using Density Functional Calculations, Sudip Pokharel May 2024

Investigate The Importance Of Local Magnetic Moment And Magnetic Interaction In Superconducting Fese Monolayer Using Density Functional Calculations, Sudip Pokharel

Graduate Theses and Dissertations

In this dissertation, we present two projects to study superconducting FeSe monolayer using first-principles density functional calculations. Monolayer FeSe/SrTiO3 system has very different properties as compared to its bulk counterpart in terms of critical superconducting temperature, Fermi surface topology and antiferromagnetic (AFM) stability. For FeSe monolayer, local magnetic moment (LMM) and AFM fluctuation are closely linked to superconductivity. However, LMM is not studied enough for FeSe monolayer. For FeSe/SrTiO3 system, the substrate SrTiO3 constrains the in-plane lattice constant for FeSe and also plays a crucial role in the onset and enhancement of superconductivity by providing charge transfer. …


The Gravitational Wave Peep: Improved Modeling Of Highly Eccentric Emris For Lisa Signal Confusion Noise, Daniel Joseph Oliver May 2024

The Gravitational Wave Peep: Improved Modeling Of Highly Eccentric Emris For Lisa Signal Confusion Noise, Daniel Joseph Oliver

Graduate Theses and Dissertations

Scattering events around a massive black hole will occasionally toss a stellar-mass compact object into an orbit around the massive black hole, beginning an extreme mass ratio inspiral. The early stages of such a highly eccentric orbit will not produce detectable gravitational waves as the source will only be in a suitable frequency band briefly when it is close to periapsis during each long-period orbit. This burst of emission, firmly in the millihertz band, is the gravitational wave peep. While a single peep is not likely to be detectable, if we consider an ensemble of such subthreshold sources, spread across …


Derived Jet Schemes And Arc Spaces, And Arithmetic Arc Space Representability, C. Eric Overton-Walker May 2024

Derived Jet Schemes And Arc Spaces, And Arithmetic Arc Space Representability, C. Eric Overton-Walker

Graduate Theses and Dissertations

Associated to a given scheme X one can define geometric and arithmetic notions of jet schemes and arc spaces. We develop a construction of the geometric jets and arcs in the setting of derived schemes and explore consequences thereof. In particular, we prove an analogous theorem to that of one by Tommaso de Fernex and Roi Docampo concerning the cotangent sheaves of geometric jets and arcs. Our version then produces many subsequent results which allow us to prove stronger versions of results concerning geometric jets and arcs by removing unnecessary hypotheses. Separately, we explore evidence as to why, in contrast …


An Inductive Analysis Examining Factors Contributing To Student Attrition In Introductory College Chemistry Courses And Proposed Solutions., Zephaniah Daniel Greenwell May 2024

An Inductive Analysis Examining Factors Contributing To Student Attrition In Introductory College Chemistry Courses And Proposed Solutions., Zephaniah Daniel Greenwell

Graduate Theses and Dissertations

A grounded theory study was conducted to investigate possible methods for reducing the number of “D”, “F”, or “W” grades (DFW rate) in the 1st semester general chemistry course. Classroom observations conducted over the 2022-2023 school year resulted in a 17 questions survey that was distributed in both the fall 2023 and spring 2024 semesters with 157 total student responses. While these surveys were being collected, an interview protocol was developed for students and instructors, who have experience teaching or taking an introductory chemistry course. These interviews were conducted in the early spring 2024 semester. Ten undergraduate students, six graduate …


Decoding Usage And Adoption Behavior Of The Low-Carbon Transportation Market: An Ai-Driven Exploration, Vuban Chowdhury Dec 2023

Decoding Usage And Adoption Behavior Of The Low-Carbon Transportation Market: An Ai-Driven Exploration, Vuban Chowdhury

Graduate Theses and Dissertations

The transportation sector stands as a significant contributor to greenhouse gas emissions in the United States, with its environmental impact steadily escalating over the past few decades. This has prompted government agencies to facilitate the adoption and usage of low-carbon transportation (LCT) options as alternatives to fossil-fuel-powered transportation. LCTs include modes of transportation that minimize the overall carbon footprint of the transportation sector by relying on energy sources that are environmentally sustainable. These sustainable transportation options have also garnered significant interest in the transportation research community. For government agencies and researchers alike, a comprehensive understanding of the adoption and usage …


Standing On The Edge Of A Dream, Parto Ahmadpour Mobarake Dec 2023

Standing On The Edge Of A Dream, Parto Ahmadpour Mobarake

Graduate Theses and Dissertations

Standing On the Edge of a Dream delves into the intricate tapestry of lived experiences shaped by relocation, emphasizing the nuanced space that exists between reality and imagination. As an individual who has undergone the transformative journey of immigration, I recognize that the concept of relocation is like standing on the edge of a dream. This notion becomes a living structure, intricately woven with threads from our past, present, and future. My artistic exploration extends beyond my artworks, yet it remains deeply rooted in my personal narratives. The artworks in the exhibition continue to draw inspiration from personal memories and …