Digital Commons Network^™

The Impact Of Reliability In Conceptual Design - An Integrated Trade-Off Analysis, Tevari James Barker

Graduate Theses and Dissertations

Research presented in this paper focuses on developing models to estimate the systemreliability of Unmanned Ground Vehicles using knowledge and data from similar systems. Traditional reliability approaches often require detailed knowledge of a system and are used in later design stages as well as development, operational test and evaluation, and operations. The critical role of reliability and its impact on acquisition program performance, cost, and schedule motivate the need for improved system reliability models in the early design stages. Reliability is often a stand-alone requirement and not fully included in performance and life cycle cost models. This research seeks to …

Bumpers College Of Agricultural, Food And Life Sciences Professional Development Opportunities And Their Impact On Perceptions Of Career Preparedness, Jessica L. Wesson

Graduate Theses and Dissertations

A student’s undergraduate education is an imperative part of developing career skills that will prepare them to transition from academia to the professional world. Experience outside of the classroom and course material taught in a formal class experience are both important. Their experiences and classes, in college, allow them to develop skills and increase their chances of being successful in the workplace (Suvedi et al., 2016).

Chickering’s Seven Vectors of Student Development were used to help explain the process of student development. A quantitative survey was sent to DBCALFS faculty, staff, and administrators, and a different quantitative survey was sent …

Framework Of Hardware Trojan Detection Leveraging Structural Checking Tool, Rafael Dacanay Del Carmen

Graduate Theses and Dissertations

Since there is a significant demand for obtaining third-party soft Intellectual Property (IP) by first-party integrated circuit (IC) vendors, it is becoming easier for adversaries to insert malicious logic known as hardware Trojans into designs. Due to this, vendors need to find ways to screen the third-party IPs for possible security threats and then mitigate them. The development of the Structural Checking (SC) tool provides a solution to this issue. This tool analyzes the structure of an unknown soft IP design and creates a network of all the signals within the design and how they are connected to each other. …

Teaching For Career Success: An Agricultural Industry Perspective Of Preparedness Needs For Diverse Workforce Development, Madelaine Giebler

Graduate Theses and Dissertations

This research examined agricultural graduate preparedness needs through the lens of agricultural industry professionals. In the rapidly changing industry environment, continual review of agricultural curriculum needs provides relevant curriculum recommendations for academic programs. This study came at a time when agricultural curriculum was in need of review. Methodology for this study involved a qualitative mixed methods approach employing survey and interview responses. A total of 121 industry professionals, identified through the University of Arkansas Bumpers College Career Development Center, were contacted with the survey link. A total of eighteen individuals completed the surveys, and of those eighteen survey respondents, eight …

Fabrication Of Mof Films Of Uio Or Pcn Type Through Layer-By-Layer Molecular Deposition As Well As Bulk Deposition For Catalytic Applications, John Ozdemir

Graduate Theses and Dissertations

Metal-organic frameworks (MOFs) are crystalline, porous materials comprised of symmetric organic linkers coordinated to positively charged metal atoms or metal oxide nodes. This dissertation uses strategies in crystal engineering to advance the study of functional MOFs with emphasis on thin film deposition. The first chapter of this dissertation will introduce the field of reticular chemistry to the reader and describe synthetic efforts to develop useful building blocks for MOF materials: namely porphyrin macrocycles and carboxylate capped zirconium-oxo and hafnium-oxo clusters. The building blocks for MOFs developed in the first chapter will be employed in the second and third chapters through …

“Implacement”: The Importance Of Place And Community In Schooling, Emily Coady

Graduate Theses and Dissertations

This dissertation consists of three chapters exploring my overarching research question: How does sense of place shape a teacher’s orientation to their profession? My first chapter empirically answers the question: Is there a relationship between place attachment and measured aspects of teacher quality? In an attempt to qualify the strength of bond between a teacher and his or her community, I adapted a place attachment instrument developed by Raymond, Brown, and Weber (2010). Each teacher is given a place attachment score informed by their responses on the 21-item survey. Next, I correlated these scores to other aspects of teacher quality …

The Hard Work Is Worth It: Overcoming Unfavorable Determinants To Pass Pro-Immigrant Education Policy In A Conservative State Legislature, Megan Cardwell Godfrey

Graduate Theses and Dissertations

Immigrants, English learners (ELs), and culturally and linguistically diverse (CLD)students often lag behind their White, monolingual peers in academic achievement and English language proficiency. While there are policy solutions to improve academic and linguistic opportunities and outcomes for immigrant/EL/CLD students, such as implementing bilingual instructional models and increasing teacher diversity, these pro-immigrant policies can be hard to come by in some legislative contexts due to unfavorable economic, social, or political determinants. This qualitative case study analyzed the multifaceted political work that contributed to the passage of two pro-immigrant education policies in the Arkansas 93rd General Assembly: a bill for bilingual …

A Social Media Strategy Plan For The Jane B. Gearhart Full Circle Food Pantry, Sara Katelyn Holm

Graduate Theses and Dissertations

The Jane B. Gearhart (JBG) Full Circle Food Pantry is a student-led program that provides food assistance for members of the University of Arkansas community. This thesis project includes a social media strategy plan that aims to increase the overall awareness of the pantry and its multifaceted services to decrease food insecurity levels at the University of Arkansas. This plan intends to create behavioral changes that expand usage of the pantry and social media engagement among UA students. Grounded in data-driven insights, this plan is designed from (i) literature on food pantry marketing techniques; (ii) a review of the pantry's …

Reconstructing Bison And Mammoth Migration During The Late Pleistocene And Early Holocene Of Central Texas Using Strontium Isotopes, Joshua John Porter

Graduate Theses and Dissertations

During the Late Pleistocene (LP; past 130,000 years), over two-thirds of large mammal (>45kg) species went extinct globally. While the role of humans is hotly debated, the effect of these extinctions is growing clearer; the extinctions resulted in widespread and lasting faunal community reorganization. However, the impact of these extinctions on dietary and migratory behavior within faunal communities is unknown. Our study examines the impact of the megafaunal extinctions on the dietary and migratory behavior of surviving Bison individuals in Texas using carbon, oxygen, and strontium isotopes. Strontium isotopes are incorporated into mammalian enamel during their tooth development and …

Understanding Interfacial Reactions Initiating On Electrode Materials For Energy Storage Technologies, Jingnan Li

Graduate Theses and Dissertations

Since the first generation of lithium-ion batteries featured lithium cobalt oxide cathode and carbon anode commercialized in the 1990s, the high-capacity materials with lower cost are in demand to further increase the battery energy density. Lithium metal and silicon anode are promising high-capacity anode materials to achieve next-generation lithium batteries. However, both the materials actively react in electrolytes and suffer from dramatic volume change. Therefore, a reliable passivation layer at the electrolyte/electrode interphase (i.e., solid electrolyte interphase, or “SEI”) is required to support the long-term cycling of both materials. Cetrimonium hydro fluoride (CTAHF2) has been proposed and synthesized as an …

Science Teachers' Perceptions Of Culturally Responsive Teaching In Majority Native American Schools In Oklahoma, Michelle Childress

Graduate Theses and Dissertations

Native American students have consistently scored less than their white peers on high school academic achievement tests, have the lowest high school graduation rates, and have the lowest college enrollment rates. Research has evidenced challenges and struggles Native American children are faced with that negatively effects their success in the classroom. Native American students often encounter a disconnect between their home and school life resulting in difficulties of navigating two opposing worlds. When Native American students are associated with negative stereotype’s indicative of Native American culture as opposed to the dominant culture, this creates a conflict between their cultural identity …

High Power Density And High Efficiency Converter Topologies For Renewable Energy Conversion And Ev Applications, Dereje Lemma Woldegiorgis

Graduate Theses and Dissertations

This dissertation work presents two novel converter topologies (a three-level ANPC inverter utilizing hybrid Si/SiC switches and an Asymmetric Alternate Arm Converter (AAAC) topology) that are suitable for high efficiency and high-power density energy conversion systems. The operation principle, modulation, and control strategy of these newly introduced converter topologies are presented in detail supported by simulation and experimental results. A thorough design optimization of these converter topologies (Si/SiC current rating ratio optimization and gate control strategies for the three-level ANPC inverter topology and component sizing for the asymmetric alternate arm converter topology) are also presented.

Performance comparison of the proposed …

Analysis And Optimization Of The Two-Phase Series Capacitor Buck Dc-Dc Converter, Salahaldein Ali Aboajila Ahmed

Graduate Theses and Dissertations

Current sharing schemes for conventional multi-phase converters are based on sensing each phase current to deliver the current information to their controllers. In conventional buck converters, this fact may require a preset current sharing ratio at the expense of efficiency, which eventually requires a larger sensing circuit to achieve the sensing accuracy of each phase. Introducing the concept of automatic current sharing is one of the solutions to tackle this issue. Automatic current sharing (Current Sharing Mechanism CSM) is an advanced way to distribute heat generation in multi-phase switching topologies at full load. A two-phase series capacitor buck converter (2-pscB) …

Algorithms Vs. Human Nature: A Tale Of Selective Exposure, Dené E. M. Wamsley

Graduate Theses and Dissertations

The public’s turn towards news websites and social media for news consumption has sparked anxiety over echo chambers, avoidance of opinion-challenging content, and potentially fragmentation and polarization among sociopolitical groups. Algorithms have specifically been blamed for increasing the ease of filtering out counter-attitudinal online content and potentially exacerbating selective exposure tendencies. However, longstanding classic psychological research has demonstrated the ubiquitous phenomenon of cognitive dissonance and selective exposure far before the internet became the primary tool for news consumption. Research investigating how algorithms directly influence online approach and avoidance behavior is unfortunately scarce. This dissertation work aimed to analyze the impact …

Public Libraries In Rural Arkansas: An Oasis In An Information Desert, Britt Graves

Graduate Theses and Dissertations

Public libraries in Arkansas are welcome, but those found in rural Arkansas are almost a necessity. The public uses the library for more than just checking out books or their email: it’s become a community gathering place for all walks of life, regardless of age or economic status. When the Covid-19 pandemic hit the state, libraries also became essential for education, medicine, news, and employment, nearly overloading their resources and shining a spotlight on technology, or the lack thereof, that so many public libraries are needing. With the Arkansas governor planning an upgrade on broadband technology and the federal government …

How Do Virtual Social Media Influencers Affect Millennial And Gen Z Female Consumers’ Purchase Intention? A Comparison Of Fast Fashion Versus Luxury Fashion Brands, Lauren Bouvier

Graduate Theses and Dissertations

With the emergence and increasing prevalence of social media, the effectiveness of social media influencers (SMIs) is apparent in today’s fast-paced life. Virtual social media influencers (VSMIs), computer-generated influencers with a real human appearance, have gained popularity. The purpose of this study is to examine important VSMI’s characteristics that affect brand image and trust which lead to purchase intention (fast fashion vs. luxury fashion brand). Social exchange theory and source credibility model were adopted to develop a theoretical framework for the present study. Two Instagram ads were developed that included the post’s image and corresponding caption: VSMI endorsing H&M and …

“Young Adult Books Don’T Realize They Have That Power”: Reader Response To Ideology In Young Adult Dystopian Fiction, Zane Emīlija Sarma

Graduate Theses and Dissertations

The purpose of this research is to find out how readers interact with novels in the Young Adult dystopian genre. I will examine the ways in which readers resist the dominant patriarchal ideological discourses in the YA dystopian novel and how readers submit to this ideology. Through an interaction with the text, the reader produces oppositional, negotiated, or preferred meanings. I will argue that readers’ response to ideology in the YA dystopian novel is affected by their active participation in reader communities such as the Bookish community online.

YA dystopian fiction was highly popular in the early 2010s, but the …

Challenging Student Behaviors And Teacher Well-Being, Dannah Steele

Graduate Theses and Dissertations

Classroom management is a necessary component of a teacher’s classroom in order for students to learn in a safe environment. When a teacher is unable to manage his or her classroom because of dangerous and disruptive behaviors, it can be physically dangerous and impede the learning of others. Teachers frequently exposed to challenging behaviors experience high levels of stress that transcends into their personal lives. The purpose of this study was to determine how administrators can better support teachers who experience high levels of stress incurred from working with students who exhibit challenging behaviors in the classroom. Data collected through …

An Engineering And Economic Analysis Of The Implementation Of The Carbo Rock-It, Lydia Huck

Graduate Theses and Dissertations

The patented Carbo Rock-It system was developed to carbonate beverages for the craft brewing industry with the goal of reducing time, cost, and environmental impacts of the carbonation process. This research field tests, models, analyzes and optimizes the engineering and economic performance of a commercial-scale Carbo Rock-It placed in production at an operating brewery (Core Brewing and Distilling Co., Springdale, AR). Field tests indicated that the Carbo Rock-It was able to successfully carbonate twelve 120 BBL batches of Scarlet Letter Seltzer to 3.0 vol/vol while meeting all beverage quality and safety requirements. The Carbo Rock-It was able to reduce carbonation …

Diffusive Dynamics Of Biological Macromolecules In The Cytoplasm Of Live Bacteria, Asmaa Ali Sadoon

Graduate Theses and Dissertations

Bacteria are small organisms that play important roles in our bodies and in maintaining our surrounding environment. However, bacterial infections are considered as one of the health diseases that threatens the lives of humans. Resistance of bacteria to antibiotics has made treating bacterial infections more challenging. With the emergence of many developed optical techniques, it has become possible to study various biological mechanisms of molecules inside these small organisms with high resolution and precise localization. In this research, single particle tracking photoactivation localization microscopy (sptPALM) technique was used to investigate the dynamics of fluorescent histonelike nucleoid-structuring proteins (H-NS) in live …

Diffusive Dynamics Of Biological Macromolecules In The Cytoplasm Of Live Bacteria, Asmaa Sadoon

Graduate Theses and Dissertations

Bacteria are small organisms that play important roles in our bodies and in maintaining our surrounding environment. However, bacterial infections are considered as one of the health diseases that threatens the lives of humans. Resistance of bacteria to antibiotics has made treating bacterial infections more challenging. With the emergence of many developed optical techniques, it has become possible to study various biological mechanisms of molecules inside these small organisms with high resolution and precise localization. In this research, single particle tracking photoactivation localization microscopy (sptPALM) technique was used to investigate the dynamics of fluorescent histonelike nucleoid-structuring proteins (H-NS) in live …

The Effect Of Tier 2 Intervention On Student Achievement & Student Self-Efficacy, Cheyenne Morgan Hill

Graduate Theses and Dissertations

Biology is a key course in a student's learning path. It provides important information about the living world and creates foundational knowledge that will be used in other science courses as the student progresses through his or her secondary and post-secondary education. However, there is a pattern of low student achievement in this required science course. The inability for students to understand and retain the curriculum in turn leads to low self-efficacy. Together, this creates a poor attitude toward science and a reluctance to pursue further science courses and in turn science careers. Response to Intervention (RTI), a common educational …

Ab Initio Studies Of Structure And Properties Of Group-Iv Monochalcogenide Monolayers, Shiva Prasad Poudel

Graduate Theses and Dissertations

The goal of this dissertation is to study the structure of ferroelectric group-IV monochalcogenide monolayers (MMLs) and their material properties. This work also established a new buckled honeycomb phase of these monolayers. Chapter 1 serves as an introduction where the motivation for these studies is established. In chapter 2, I used eight different exchange-correlation functionals (XC) to study the structure of these 2D ferroelectrics and found that their properties are independent of the choice of XC functionals. These findings reveal that the ground-state ferroelectric unit cell can be described by only five independent parameters, whereas their paraelectric (square or rectangular) …

Optimized Damage Assessment And Recovery Through Data Categorization In Critical Infrastructure System., Shruthi Ramakrishnan

Graduate Theses and Dissertations

Critical infrastructures (CI) play a vital role in majority of the fields and sectors worldwide. It contributes a lot towards the economy of nations and towards the wellbeing of the society. They are highly coupled, interconnected and their interdependencies make them more complex systems. Thus, when a damage occurs in a CI system, its complex interdependencies make it get subjected to cascading effects which propagates faster from one infrastructure to another resulting in wide service degradations which in turn causes economic and societal effects. The propagation of cascading effects of disruptive events could be handled efficiently if the assessment and …

Increasing Active Learning And Achievement In A Large Lecture Calculus Class Through A Flipped Classroom Model, Kimberly King

Graduate Theses and Dissertations

University Calculus I courses serve as a means of access into high demand STEM fields and large lecture style passive calculus courses can be difficult for students. A mixed methods research design was used to compare a flipped instructional approach to a traditional lecture approach in large section Calculus I courses. The flipped lecture model required students to view videos of calculus instruction that included embedded quiz questions to allow for problem solving explorations during face-to-face class time. The traditional format included content from the video and limited time for additional problem solving. A professor with prior experience teaching Calculus …

Design, Fabrication, And Characterization Of An Array Of Graphene Based Variable Capacitors, Millicent Nkirote Gikunda

Graduate Theses and Dissertations

Since it was first isolated and characterized in 2004, graphene has shown the potential for a technological revolution. This is due to its amazing physical properties such as high electrical conductivity, high thermal conductivity, and extreme flexibility. Freestanding graphene membranes naturally possesses an intrinsic rippled structure, and these ripples are in constant random motion even room temperatures. Occasionally, the ripples undergo spontaneous buckling (change of curvature from concave to convex and vice versa) and the potential energy associated with this is a double well potential. This movement of graphene is a potential source of vibrational energy.

In this dissertation, we …

Development Of A Long-Read Sequencing Protocol To Assess The Precision And Efficacy Of Gene Editing For Duchenne Muscular Dystrophy, Landon Andrew Burcham

Graduate Theses and Dissertations

This work establishes a method for assessing on-target precision due to CRISPR-Cas9 gene editing, especially within the context of exon skipping therapy for Duchenne Muscular Dystrophy. The proposed method utilizes an Oxford nanopore long-read sequencing approach to sequence amplified regions of DNA that have been edited using CRISPR-Cas9. NIH3T3 and C2C12 cell lines were treated with a dual-guide CRISPR-Cas9 system, that targets and deletes exon 23 from the DMD gene in mouse samples. Deletion PCR revealed deletion of exon 23 in both DNA and cDNA samples. Additionally, sequencing using Oxford Nanopore revealed targeted exon 23 deletion as the most prevalent …

Crystal Growth And Property Tuning Of Layered Magnetic Topological Semimetals, Krishna Pandey

Graduate Theses and Dissertations

The demand for energy-efficient devices has been growing rapidly due to the need for data-driven technologies and the global energy crisis. As device size approaches the atomic scale, the miniaturization of electronic devices may stop in the near future unless fundamentally new materials or device concepts are developed. The emergent topological materials with exotic properties show remarkable robustness against crystal lattice defects, which are promising for next-generation technology. These materials host exotic properties such as high mobility, large magnetoresistance, chiral anomaly, and surface Fermi arcs, etc. Among various topological materials, the ZrSiS-family materials exhibit two types of Dirac states, which …

Introduction Of Human Acidic Fibroblast Growth Factor (Fgf1) Variant With Increased Stability And Bioactivity, Azadeh Tavousi Tabatabaei

Graduate Theses and Dissertations

Human acidic Fibroblast Growth Factor 1 (FGF-1) involves in a broad spectrum of biological processes, including cell growth, proliferation, differentiation, migration, angiogenesis, wound healing, and embryonic development. hFGF1 non-selectively binds to cell surface hFGF receptor isoforms to elicit these cell-signaling processes. Since hFGF1 plays a significant role in tissue repair activity, that is a prime candidate for novel wound healing therapeutics. However, hFGF1 has been found to unfold near physiological temperature due to a strong electrostatic repulsion created by a dense cluster of positively charged amino acids near the c-terminus. The problem not only leads to proteolytic degradation of the …

Robust And Fair Machine Learning Under Distribution Shift, Wei Du

Graduate Theses and Dissertations

Machine learning algorithms have been widely used in real world applications. The development of these techniques has brought huge benefits for many AI-related tasks, such as natural language processing, image classification, video analysis, and so forth. In traditional machine learning algorithms, we usually assume that the training data and test data are independently and identically distributed (iid), indicating that the model learned from the training data can be well applied to the test data with good prediction performance. However, this assumption is quite restrictive because the distribution shift can exist from the training data to the test data in many …