Digital Commons Network^™

The Foundation Of A Grand Unified Metaphysics, Jason R. Miller

Graduate Theses and Dissertations

Philosophers from Leibniz to Parfit have tackled the problem of existence and the problem of arbitrarity. I divide the solutions to these two problems into three general categories: (1) infinite regress answers, (2) ex nihilo answers, and (3) self-caused cause answers. I show that the first two (infinite regress and ex nihilo) categories of answers either fail to answer the problem of existence or the problem of arbitrarity or fail to satisfy one or more reasonable assumptions about said problems. Believing it to be useful to a self-caused cause answer to the problem of existence and the problem of arbitrarily, …

Studies Of Avian Nasal Mites (Acari: Rhinonyssidae And Ereynetidae) And Their Interaction With The Brood Parasite Brown-Headed Cowbird (Molothrus Ater: Icteridae) And Phylogenetic Inferences Of The Genus Ptilonyssus (Rhinonyssidae) On Different Passerine Hosts Associated To Three States In The Us, Alexis D. Hilario Perez

Graduate Theses and Dissertations

Nasal mites are endoparasites that spend their entire life cycle inside the nasal cavities and respiratory passages of birds. The Brown-Headed cowbird (Molothrus ater) (BHCO) is an icterid bird that uses brood parasitism as a reproductive strategy in which it lays an egg in the nest of a different bird species and allows the host to raise its young. Interestingly, nasal mites reported from cowbirds represent the same species found infesting other icterids and other common host groups. In the first study, I examined how diversity and host prevalence might change in a large sample size of BHCO associated with …

Deep Learning Strategies For Pool Boiling Heat Flux Prediction Using Image Sequences, Connor Heo

Graduate Theses and Dissertations

The understanding of bubble dynamics during boiling is critical to the design of advanced heater surfaces to improve the boiling heat transfer. The stochastic bubble nucleation, growth, and coalescence processes have made it challenging to obtain mechanistic models that can predict boiling heat flux based on the bubble dynamics. Traditional boiling image analysis relies on the extraction of the dominant physical quantities from the images and is thus limited to the existing knowledge of these quantities. Recently, machine-learning-aided analysis has shown success in boiling crisis detection, heat flux prediction, real-time image analysis, etc., whereas most of the existing studies are …

Investigating Depth Estimation To Archaeological Magnetic Source Bodies, Jeremy G. Menzer

Graduate Theses and Dissertations

Magnetometry is the most widely applied archaeo-geophysical technique. Current practice standards employ the technique to map only in a two-dimensional plan view fashion, but in deep geologic studies depth estimators are routinely applied to magnetic datasets. These estimators provide three-dimensional information to magnetic source-bodies. There are many different depth estimators employed in geologic study that all require various degrees of processing complexity. This study investigates two mathematically simple techniques, half-width rules and multi-height methods. Half-width rules are likely the oldest depth estimators within the field while multi-height techniques are but a minor footnote in the literature. The applicability of these …

Nonmetallic Jet Impingement Thermal Management For Power Electronics Via Additive Manufacturing, Reece Whitt

Graduate Theses and Dissertations

The increase in energy demanded by transportation and energy sectors has necessitated highly efficient thermal management for reliable power electronics operations. Conventional cooling techniques are limited by their inability to target switching location hot spot temperatures, leading to non-uniform thermal gradients. These devices, such as cold plates and heat sinks, also utilize heavy metallic structures that can accentuate electromagnetic interferences generated by high voltage switching processes. This work proposes a non-metallic jet impingement cooler for more customized thermal management, while simultaneously reducing the harmful effects of electromagnetic interferences. Additive manufacturing is utilized to enable jet impingement zones to target individual …

Combined Stressors In Reliability Failure Modes In Flip-Chip Electronic Packaging, Mahsa Montazeri

Graduate Theses and Dissertations

The trend toward miniaturization of electronic devices to fulfill Moore’s law introduces new reliability concerns to the electronic packaging process while worsening existing primary challenges. In solder interconnect specifically, temperature cycling is one of the prominent failure threats. However, with further downscaling of the flip-chip solder connections, electromigration also present a precarious failure mode in these interconnects. On the other hand, understanding the degradation mechanism in solders is crucial for the power electronic products' reliability considering the industrial tendency to replace wirebonds with solder attachment while improving the current carry capacity. This dissertation utilizes FEA simulation and an experimental approach …

Mission Profile Effects On Automotive Drivetrain Electronics Reliability: Modeling And Mitigation, Bakhtiyar Mohammad Nafis

Graduate Theses and Dissertations

The reliability of electronic devices is dependent upon the conditions to which they are subject. Temperature variations coupled with differences in thermal expansion between bonded materials results in thermomechanical stresses to build up, which can instigate failure in the interconnects or other critical regions. With the move towards electrification in the automotive industry, there is the increasingly important consideration of powertrain electronics reliability, the pertinent conditions being governed by the drive cycle or mission profile of the vehicle. The mission profile determines the power dissipated by the electronic devices, which determines the peak and mean temperature, temperature swing and the …

Thermometry Via Diffusion In Ferrous Core-Shell Nanoparticles For Induction Heating Applications, Hayden Carlton

Graduate Theses and Dissertations

Induction heating causes the release of enormous amounts of heat from dispersed magnetic nanoparticles. While the rate of heat transfer can be easily quantified calorimetrically, measuring the temperature of the nanoparticles on the nanoscale presents experimental challenges. Fully characterizing the temperature and thermal output of these magnetic particles is necessary to gauge overall heating efficiency and to provide a more holistic understanding of heat transfer on the nanoscale. Herein, this dissertation seeks to develop a novel nanoparticle thermometry technique, which correlates diffusion behavior in core-shell nanoparticles to local temperature. Initial measurements suggested that heating silica capped ferrous nanoparticles (SCNPs) via …

Improve The Prediction Of Camber, Deflection, And Prestress Losses In Precast, Prestressed Concrete Bridge Girders, Ahmed Ali Hussein Al Mohammedi

Graduate Theses and Dissertations

Many precast, prestressed concrete girders have camber less or higher than the design values. This discrepancy between the design and the actual camber creates construction problems when installing the cast-in-place concrete deck. The objective of this research was to improve the accuracy of estimating long-term camber, deflection, and prestress losses of precast, prestressed concrete girders.

The experimental program consisted of measuring concrete properties and performing field measurements of camber, deflection, and prestress losses for girders in Arkansas. The investigation involved testing nine full-scale girders from two prestressed concrete plants that regularly supply concrete girders to bridge projects in Arkansas. The …

Designing Digital Antiquity: Classical Archaeology In New Virtual Applications, William Loder

Graduate Theses and Dissertations

In this thesis, I argue that the combination of existing archaeological theory with game design theory offers an innovative avenue for creating serious 3D applications of archaeological sites in virtual reality that can be productively used for pedagogical, research, and outreach solutions. In this thesis, I engage with the archaeological theories of phenomenology and sensory studies, briefly touching on structure and agency as well as discussion of some current digital applications in use in the field. For this project, I am interested in game design theory as it relates to education and I view Virtual Reality as an important tool …

An Assessment Of The Neurovascular Structures Of The Trigeminal Nerve And Their Relationship To Diet In Primates, Caitlin Yoakum

Graduate Theses and Dissertations

The inferior alveolar nerve (IAN) enters the mandible via the mental foramen, supplies nervous sensation to the mandibular teeth as it travels through the mandibular canal, and exits the mandibular foramen to send information to the brain to maintain chewing cycles and protect the teeth from damage. Although bony canals and foramina have been shown to form around soft-tissue structures, there are some examples (e.g., the hypoglossal nerve/canal) where the nervous structures do not comprise most of the canal/foramina space. It is important to know the size of nerves because it has been established that larger nerves convey more information …

Statistical Modeling, Learning And Computing For Stochastic Dynamics Of Complex Systems, Mohammadmahdi Hajiha

Graduate Theses and Dissertations

With the recent advances in sensor technology, it is much easier to collect and store streams of system operational and environmental (SOE) data. These data can be used as input to model the underlying behavior of complex engineered systems and phenomenons if appropriate algorithms with well-defined assumptions are developed. This dissertation is comprised of the research work to show the applicability of SOE data when fed into proposed tailored algorithms. The first purposes of these algorithms are to estimate and analyze the reliability of a system as elaborated in Chapter 2. This chapter provides the derivation of closed-form expressions that …

Remixed, Remastered: Investigating Organizational Adaptation In Higher Music Education, Jacob Bruce Hertzog

Graduate Theses and Dissertations

Higher music education presents a unique opportunity to examine change within higher education due to the digital revolution in the music industry over the past two decades. The purpose for conducting this study was to describe, map, and explain the strategies that higher music education programs are using to adapt to the digital revolution in the music industry. This study was grounded in organizational adaptation theory, drawing upon nine well-established theories: population ecology, life cycles, strategic choice, isomorphism, symbolic action, resource dependence, cybernetics, and network theory. Critical concepts of the turbulent environment, environmental perception, and organizational adaptation strategy emerged from …

The Role Of Sex: An Analysis Of U.S. Attitudes Toward Climate Change, Chloe Riggs

Graduate Theses and Dissertations

This study analyzes the intersection of sex, environmental risk perception of climate change, and feminism. More specifically, with a sample size of 8,280 respondents from the American National Election Studies (ANES) 2020 Times Series Study, this research examines the relationship between pro-environmental attitudes and sympathy for feminism, controlling for sex, as well as if a measure of sympathy for feminism influences pro-environmental attitudes, controlling for demographic (age, education, race, sex, and income) and political preference (political ideology and party affiliation) variables. Previous literature strongly supports a sex gap in risk perception, a pattern known as the White Male Effect (WME) …

News Media Trust And Mistrust During The Covid-19 Pandemic, Kaitlyn Seiter

Graduate Theses and Dissertations

With the uncertainty and growing information surrounding the COVID-19 pandemic, news media consumption has increased drastically compared to pre-pandemic consumption. At the start of the pandemic, 94% of Americans reported closely following COVID-19 news, with more than half of Americans spending more than two hours consuming COVID-19 news everyday (SSRS, 2020). With the news media serving as a critical source of information through this public health crisis, the public’s reactions, behaviors, and attitudes to the pandemic stem from the level of trust they have in the news media to share COVID-19 information. Because of this, this study examines trust in …

Theoretical Investigations Of The Structural, Dynamical, Electronic, Magnetic, And Thermoelectric Properties Of Corhysi (Y = Cr, Mn) Quaternary Heusler Alloys, Abdullah Hussain Hzzazi

Graduate Theses and Dissertations

Thermoelectric materials have potential properties for utilizing waste heat. The computations are used to estimate the electronic structure of CoRhYSi (Y = Cr, Mn) Quaternary Heusler alloys, as well as their elastic and magnetic characteristics. The full-potential linearized augmented plane wave is used in the calculations. The exchange-correlations are addressed using Perdew–Burke and Ernzerhof's generalized gradient approximation (GGA-PBE). With the exception of CoRhCrSi and CoRhMnSi, which are simple ferromagnets that are approximately half metallic in nature, electronic structure calculations demonstrate that these compounds have a gap in the minority states band and are obviously half-metallic ferromagnets. The magnetic moments of …

Palmer Amaranth [Amaranthus Palmeri (S.) Wats.] Resistance To S-Metolachlor In The Mid-Southern Us And S-Metolachlor Dissipation In Soil, Koffi Badou Jeremie Kouame

Graduate Theses and Dissertations

Palmer amaranth [Amaranthus palmeri (S.) Wats.] presents both a high genetic diversity and propensity to evolve resistance to herbicides of several sites-of-action which have made it one of the worst weeds in US agriculture. In Arkansas, Palmer amaranth is resistant to herbicides of seven sites-of-action, which are 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) inhibitor, acetolactate synthase inhibitors, microtubule inhibitors, protoporphyrinogen oxidase inhibitors, very long chain fatty acid inhibitors, glutamine synthetase inhibitors, and hydroxyphenylpyruvate dioxygenase inhibitors. Sustainable management requires a better understanding of its biology and that of herbicide environmental fate. This research had five objectives: 1) characterize the current status of Palmer amaranth …

Grid Homology Invariants For Singular Legendrian Links, Richard Michael Shumate

Graduate Theses and Dissertations

If $\Lambda_{1}^{\ast}$ and $\Lambda_{2}^{\ast}$ are two oriented singular Legendrian links that are Legendrian isotopic, we first construct front diagram representations of $\Lambda_{1}^{\ast}$ and $\Lambda_{2}^{\ast}$ that have a natural allowable singular gird diagram associated to them. These allowable singular grid diagrams will always correspond to singular Legendrian links. The grid Legendrian invariants, $\lambda^{\pm}$, in the nonsingular grid homology theory have a natural extension to the singular grid theory, and are natural under the newly defined singular grid moves. This gives an invariant of singular Legendrian links, and in fact, a broader class of singular links.

Forced And Unforced Permafrost Changes In The Northern Hemisphere During 1901-2100, Hong Guo

Graduate Theses and Dissertations

Permafrost regions are very sensitive to rapid changes in climate and environment. In recent decades, there has been growing interest to better understand the permafrost degradation over the Northern Hemisphere in the context of human-induced climate change. Understanding permafrost dynamics is not only important for infrastructure but also for environmental protection in cold regions. In-situ permafrost measurements are important for assessing permafrost conditions. However, direct permafrost observations are sparse and asymmetrical in both spatial and temporal coverage. Active layer thickness (ALT) modeling is another approach that can overcome many of these limitations, but the models have large uncertainty in predicting …

The Effects Of Commercial Harvest On The Density And Demography Of Aquatic Turtles In Arkansas, Andrhea Darleen Massey

Graduate Theses and Dissertations

The United States is home to the second highest concentration of turtle species in the world, after Asia. As of 2018, there are 57 turtle species recognized within the US, 40% of which are listed as threatened or endangered, with the primary threats to population persistence identified as over-consumption and/or habitat loss. Within the US, the Mississippi Alluvial Valley (MAV) region represents the second highest turtle species richness, after the Mobile River Basin. The MAV region of Arkansas is one of the least regulated in terms of commercial aquatic turtle harvest and has undergone large-scale habitat conversion from bottomland hardwood …

Efficacy Of Spirulina (Arthrospira Platensis) Utilization In Broiler Diets, Garrett James Mullenix

Graduate Theses and Dissertations

Spirulina (Arthrospira platensis) is a cyanobacteria microalgae that has potential as an animal feed ingredient. Five experiments were conducted to further assess its ability to serve as a protein source in broiler diets. Experiment 1 consisted of an amino acid digestibility and apparent metabolizable energy assay. The results indicated that the standardized ileal amino acid levels of spirulina are comparable with typical soybean meal. Experiment 2 assessed the performance and processing parameters of broilers fed 10% spirulina in low crude protein diets, using published digestibility coefficients. Spirulina inclusion improved footpad quality and increased redness and yellowness of the breast, skin …

Study Of Thick Indium Gallium Nitride Graded Structures For Future Solar Cell Applications, Manal Abdullah Aldawsari

Graduate Theses and Dissertations

Indium gallium nitride (InxGa1-xN) materials have held great potential for the optoelectronic industry due to their electrical and optical properties. The tunable band gap that can span the solar spectrum was one of the most significant features that attracted researchers’ attention. The band gap can be varied continuously from 0.77 eV for InN to 3.42 eV for GaN, covering the solar spectrum from near infrared to near ultraviolet. Additionally, it has a high absorption coefficient on the order of ∼105 cm−1, a direct band gap, high radiation resistance, thermal stability, and so on. Nevertheless, the epitaxial growth of high quality …

In The Line Of Duty - A Documentary Film About Davis Duty And His Seeing Eye Dog, Paulina Sobczak

Graduate Theses and Dissertations

“In the Line of Duty” is a documentary film about Jeff Davis Duty, a man from a small town in Arkansas, who lost his sight at the age of five. He is the oldest Seeing Eye dog user in the world. At the age of 22, he was awarded a Fulbright Scholarship at the London School of Economics in England, as the first Fulbright Scholar with disability. Duty achieved great success in his career as a lawyer, leading a fulfilling and enjoyable life. The documentary film’s storytelling focuses on Duty’s life from his childhood to current times and presents all …

The Same River Twice, Claire Remy Pincumbe

Graduate Theses and Dissertations

This thesis is a portion of a novel written during my time at the University of Arkansas.

Does Self-Reference In Concept Mapping Influence Transfer?, Daniel A. Parker

Graduate Theses and Dissertations

Concept maps are a popular learning activity that have successfully demonstrated student learning outcomes. Research suggests that concept mapping has a positive effect on recognition, recall, and transfer. Likewise, researchers in cognitive psychology have shown the value of referencing oneself with a concept. Known as the self-reference effect, learners who connect their experiences or traits with new knowledge are more likely to remember that knowledge than if they used other mnemonic devices. Previous research suggests that integrating self-reference in concept mapping may improve recall. However, to date, no study has investigated the influence of this combination on higher order learning …

Alone Together: The Experiences Of Lgbtqia+ Undergraduates At Faith-Based Colleges, Jennifer Edwards

Graduate Theses and Dissertations

This qualitative study aimed to explore the experiences of LGBTQIA+ alumnix who attended faith-based colleges. The study was guided by Strayhorn’s (2019) College Students’ Sense of Belonging Theory and Abes’ et al. (2007) Reconceptualized model of multiple dimensions of identity. The scope of experiences explored was narrowed to three of the five categories in Schreiner’s (2010a) Thriving Quotient. These categories were: positive perspective (outlook on life), social connectedness, and diverse citizenship.

The study included 11 participants from 7 faith-based colleges and represented various intersections of sexual and gender identity. The study employed constructivist grounded theory methodology, an inductive research approach …

Reducing Dietary Crude Protein: Characterization Of Branched-Chain Amino Acid Antagonism In Modern Broiler Chickens, Craig William Maynard

Graduate Theses and Dissertations

Reducing the crude protein content of broiler diets while maintaining performance has been a primary research area in nutrition. During the late 20th century, the bulk of this research has involved supplementing broiler diets with feed-grade amino acids and proving the economic benefits of their additions. To date, widespread adoption of feed-grade amino acids is limited to methionine, lysine, threonine, and to some extent valine. With valine and isoleucine gaining prevalence in commercial formulation, classic data on the antagonisms associated with the branched-chain amino acids has returned to the forefront of practical broiler nutrition research. Therefore, a series of 23 …

Precise Nitrogen Recommendations Improve Economic And Environmental Outcomes In Arkansas Rice Production, Cristin Roberts

Graduate Theses and Dissertations

Soil testing has become an increasingly important tool in making agronomically efficient production management decisions. N-STaR is a N test used in rice production and is unique in its ability to selectively quantify soil organic-N compounds which are readily mineralizable for plant N uptake and contribute to growth and yield. This study uses historical (2002–2018) adoption rates of N-STaR, which is funded through Rice Checkoff funds, to calculate the total cost savings from N-STaR adoption. These cost savings alone would be the “typical” benefits used in a benefit-cost ratio of a public ally funded research program like N-STaR. However, we …

Automated Flight Controller Adaptive Compensation For Actuator Failures In Transport Type Aircraft, Daniel James Fresella

Graduate Theses and Dissertations

Aircraft operate over a wide range of conditions including atmospheric, weight, and center ofgravity changes. This presents a substantial challenge to automatic control system designers. When these operating conditions are merged with a partial or full control surface failure, automatic flight control is near impossible with conventional controllers. Additionally, when pilots experience control failure emergencies during flight, workload and fatigue increase drastically. The continued research of automatic flight control systems that can seamlessly adapt to unmodelled failures will enable a new generation of robust aircraft control. In this paper a 9th order 6 degree of freedom aircraft model is used …

Parenting The Gifted: Caregivers’ Perspectives Of Challenges And Their Confidence To Support Their Exceptional Children, Kristi A. Mascher

Graduate Theses and Dissertations

This phenomenological study uses Bandura’s theory of self-efficacy (1977) to examine the lived experiences of eight parents of gifted children and how their experiences, both positive and negative, shape their perception of their confidence and may contribute to building future supports for gifted parents and caregivers. Qualitative data, collected through semi-structured interviews and analyzed with an interpretive/hermeneutic lens, provides seven major themes derived from the voices of parents with children of varying ages and exceptionalities. In addition, this study concludes with a discussion surrounding the additional challenges associated with parenting the exceptional, frameworks for gifted parent support systems, as well …