Digital Commons Network^™

An Experimental Study Of Evaporites On Titan: Implications For Lake Composition And Future Missions, Ellen Czaplinski

Graduate Theses and Dissertations

Titan is the only other planetary body in the solar system with liquid on the surface. With a surface temperature and pressure of 89 – 94 K and 1.5 bar (N2), respectively, Titan’s lakes are comprised of liquid hydrocarbons, predominantly methane and ethane. Over time, Titan’s lakes may evaporate, leaving behind residual deposits (evaporites). The evaporation processes and composition of the evaporites is poorly understood. I address these outstanding questions by experimentally investigating the physical and spectral properties of evaporites at Titan surface conditions using an experimental chamber.

Chapter 1 addresses the formation of ethylene evaporites. Ethylene evaporites form more …

Naturalistic Decision Making In First Sales Calls: A Narrative Study Of Experienced Technical Sales Professionals, Douglas Williams

Graduate Theses and Dissertations

The first conversation between business-to-business sellers and new customers comes with the potential for both opportunity and risk. Sellers spend substantial effort gaining the right to engage in a first call with a potential customer. This study fills a gap in the literature by exploring the role of Naturalistic Decision Making (NDM) and how it impacts the way experienced technology sales professionals navigate first conversations with new customers. NDM explores how experienced professionals make decisions in high-stakes, real world situations that are ambiguous, time-pressured, and have poorly defined goals. While NDM studies have been performed in other professional disciplines, none …

Effect Of Harvest Time On The Incidence Of Red Drupelet Reversion And Development Of Tetraploid Linkage Maps In Blackberry, Mitchell E. Armour

Graduate Theses and Dissertations

The cultivated eastern U.S. blackberry (Rubus L. subgenus Rubus Watson) has gone through tremendous strides in both trait improvement and market outreach at the University of Arkansas System Division of Agriculture (UA System). What began as primarily a pick-your-own local fruit found mostly in the wild, has become a commercialized year-round product in most major U.S. grocery retailers. This could not have been achieved without decades of diligent breeding efforts. Although the genetic improvement of fresh-market blackberries has advanced, there are still issues that need to be addressed. One issue is the prevalence of red drupelet reversion (RDR), a physiological …

Evaluating The Efficiency Of Markov Chain Monte Carlo Algorithms, Thuy Scanlon

Graduate Theses and Dissertations

Markov chain Monte Carlo (MCMC) is a simulation technique that produces a Markov chain designed to converge to a stationary distribution. In Bayesian statistics, MCMC is used to obtain samples from a posterior distribution for inference. To ensure the accuracy of estimates using MCMC samples, the convergence to the stationary distribution of an MCMC algorithm has to be checked. As computation time is a resource, optimizing the efficiency of an MCMC algorithm in terms of effective sample size (ESS) per time unit is an important goal for statisticians. In this paper, we use simulation studies to demonstrate how the Gibbs …

Live The Local: Exploring The Relationship Between Local News Media And Cities Undergoing Downtown Revitalization, Allison Wise

Graduate Theses and Dissertations

The rise in suburban development has caused many downtowns across the United States to lose residents, businesses, attractions and community engagement. City officials and planners work to create policies, designs and urban development that help to revitalize downtowns. However, how do we bring people into our downtowns to live, work and play? That is where local news coverage can have an impact. The question arises: What can city officials, event organizers, business leaders do to foster a vibrant downtown? News outlets (e.g., television, print, digital) and their corresponding social media platforms, such as Facebook and Twitter, can act as " …

Choice Overload, Information Acquisition, And Gift Incentives In An Altruistic Context: Economic Experiments Exploring Decision Making In Charitable Giving, Jessica Adach White

Graduate Theses and Dissertations

This dissertation contains three essays on economic experiments concerning altruistic motives. The first chapter, “Choice Overload and Charitable Giving: Can There Be Too Much of a Good Thing?” concentrates on the effects of list sizes of charitable options on an individual’s decision making. The second chapter, “Is No News Good News? Motivated Reasoning in Charitable Giving,” focuses on the impact of information acquisition on an individual’s altruistic contributions. Finally, the third chapter, “Thank You, but No Thank You: Gift Incentives in Charitable Giving,” investigates gift incentives and their influence on donating behavior.

In the first chapter, “Choice Overload and Charitable …

Academic Librarian Experiences And Perceived Value Of Oer Professional Development: A Case Study, Elaine Thornton

Graduate Theses and Dissertations

Academic librarianship is a constantly changing profession. Open education librarianship has developed as an area of specialization. Effective continuing professional development (CPD) for learning about open educational resources (OER) is needed to meet academic librarians' knowledge and training needs engaged in this area. This narrative case study examines the experiences and perceptions of academic librarians who completed a structured open education leadership program. Interviews were conducted with a selection of program fellows to capture the personal perspectives of the program participants. These interview narratives were transcribed and, alongside program curriculum and participant projects, utilized to answer the study's research questions …

The Preacher And Missionary War: The Political Role Of Race And Christianity In The 1831 Baptist War, Emilee Dale

Graduate Theses and Dissertations

Abolitionists from the Eighteenth Century to the mid-Nineteenth Century tended to be remembered by William Wilberforce, Joseph Soul, Thomas Clarkson, Samuel Bowly, and William Lloyd Garrison. All of these men have been extremely well represented throughout scholarship and the archives. The voices that are often left out of the archives are the men and women who fought on the frontlines for their freedom. Enslaved men and women fought to the death for their freedom and are often overshadowed by White missionaries and abolitionists in the archives. Black leaders often have less representation throughout history and scholarship due to the lack …

Resilience-Driven Post-Disruption Restoration Of Interdependent Critical Infrastructure Systems Under Uncertainty: Modeling, Risk-Averse Optimization, And Solution Approaches, Basem A. Alkhaleel

Graduate Theses and Dissertations

Critical infrastructure networks (CINs) are the backbone of modern societies, which depend on their continuous and proper functioning. Such infrastructure networks are subjected to different types of inevitable disruptive events which could affect their performance unpredictably and have direct socioeconomic consequences. Therefore, planning for disruptions to CINs has recently shifted from emphasizing pre-disruption phases of prevention and protection to post-disruption studies investigating the ability of critical infrastructures (CIs) to withstand disruptions and recover timely from them. However, post-disruption restoration planning often faces uncertainties associated with the required repair tasks and the accessibility of the underlying transportation network. Such challenges are …

Promoting Diversity In Academic Research Communities Through Multivariate Expert Recommendation, Omar Salman

Graduate Theses and Dissertations

Expert recommendation is the process of identifying individuals who have the appropriate knowledge and skills to achieve a specific task. It has been widely used in the educational environment mainly in the hiring process, paper-reviewer assignment, and assembling conference program committees. In this research, we highlight the problem of diversity and fair representation of underrepresented groups in expertise recommendation, factors that current expertise recommendation systems rarely consider. We introduce a novel way to model experts in academia by considering demographic attributes in addition to skills. We use the h-index score to quantify skills for a researcher and we identify five …

An Automated Method To Enrich And Expand Consumer Health Vocabularies Using Glove Word Embeddings, Mohammed Ibrahim

Graduate Theses and Dissertations

Clear language makes communication easier between any two parties. However, a layman may have difficulty communicating with a professional due to not understanding the specialized terms common to the domain. In healthcare, it is rare to find a layman knowledgeable in medical jargon, which can lead to poor understanding of their condition and/or treatment. To bridge this gap, several professional vocabularies and ontologies have been created to map laymen medical terms to professional medical terms and vice versa. Many of the presented vocabularies are built manually or semi-automatically requiring large investments of time and human effort and consequently the slow …

Assessing Impacts Of Winter-Hay Feeding On Soil And Forage Nutrient Dynamics In A Rotationally-Grazed Pasture System In Arkansas, Lawrence Gordon Berry Iv

Graduate Theses and Dissertations

More than 38 % of United States’ rural land area was used for grazing (i.e., pastureland or rangeland) ruminant animals in 2017, constituting the largest private land use group. The expansive nature of these lands means that grazing and pasture management decisions have potential to impact water quality as well as profit margins. As a result, beef producers are under increased pressure from economic and environmental standpoints to limit application of nutrients beyond those required to grow the forage needed for animal consumption. At the same time, a large amount of nutrients is recycled back to pasture systems directly from …

Investigation Of Iron-Nickel Based Nanoparticles As Catalysts For Oxygen Evolution Reaction (Oer), Prashant Acharya

Graduate Theses and Dissertations

Hydrogen fuel is increasingly seen as an appealing alternative by both the scientific and the industrial communities in the drive towards a clean energy future. Hydrogen, unlike fossil-based fuels, does not release carbon dioxide, a chief component of greenhouse gases, upon combustion. However, more than 95% of the hydrogen in the world is still produced by burning fossil fuels as this method is currently the only economically feasible option at a large industrial scale.

Water electrolysis shows a lot of potential in both hydrogen generation and in the storage of energy from renewable sources such as wind and sunlight. Likewise, …

Design And Validation Of A High-Power, High Density All Silicon Carbide Three-Level Inverter, Zhongjing Wang

Graduate Theses and Dissertations

Transportation electrification is clearly the road toward the future. Compared to internal combustion engine, the electrified vehicle has less carbon-dioxide emission, less maintenance costs and less operation costs. It also offers higher efficiency and safety margin. More importantly, it relieves human’s dependence on conventional fossil energy. In the electrification progress, the revolution of electric traction drive systems is one of the most important milestone. The traction system should keep high efficiency to avoid performance reduction. Moreover, the motor drive should be designed within limited space without sacrificing output power rating. Based on the road map from US Drive Electrical and …

A Computational Study Of Radiation Damage In Bilayer Silicon-Gold Structures, Cameron Hopper

Graduate Theses and Dissertations

Irradiation from sources such as nuclear reactors bombard materials with neutrons and heavy ions. The primary consequence of this irradiation is the displacement of atoms from their atomic structure. As the structure becomes damaged, the mechanical properties can change. Eventually, this can result in a failure due to embrittlement. This type of damage is hard to detect and can result in sudden, unexpected failure. Therefore, focusing on managing the consequences of irradiation has been a heavily researched topic. To manage irradiation, the focus is primarily to manage the voids and interstitials that appear during irradiation. Grain boundaries and amorphous regions …

Using Transcendental Phenomenology To Explore Elementary Teachers’ Experiences With Struggling Readers During The Social Restrictions Precipitated By The Covid-19 Pandemic, Wyann C. Stanton

Graduate Theses and Dissertations

This study provides a window into the experiences of elementary teachers with their struggling readers during the largest world-wide interruption to education that has ever been seen. This study gives insight to educational leaders and educators as they assist their struggling readers in rebounding from the disruption to school caused by the COVID-19 pandemic and as they work to improve the quality of schooling for struggling readers. Since the beginning of the pandemic, there had been a growing body of educational literature in pandemic-related information, practice, and research. Yet, there was a need to bring to light the phenomenon of …

The Persistence Of Human Norovirus Surrogate In Leafy Greens Production System, Wenjun Deng

Graduate Theses and Dissertations

Since mostly consumed raw, foodborne pathogen contamination of leafy greens has led to a large number of foodborne disease outbreaks and illnesses each year in the United States. Human noroviruses (hNoV) are the most common viral pathogen transmitted by leafy greens. In this dissertation, the persistence of the hNoV surrogate Tulane virus (TV) on pre-harvest lettuce and microgreens was investigated. Lettuces are the most studied leafy green model, while previous hNoV research has mainly focused on the post-harvest stage of production. Here, pre-harvest hydroponically grown lettuce were used to determine TV persistence on leafy greens. After inoculation on leaves at …

On The Epistemic Significance Of Expert Conversion, Dax R. Bennington

Graduate Theses and Dissertations

Much of our knowledge of the world depends on the testimony of experts. Experts sometimes change their minds and disagree with each other. What ought a novice do when an expert changes their mind? This dissertation provides an account of when expert conversion is epistemically significant and how the novice ought to rationally defer to expert conversion. In answering when expert conversion is epistemically significant, I provide a diagnostic tool that emphasizes that epistemically significant expert conversion seems to be evidence-based and that there is an absence of cognitive biases on the part of the converting expert. In answering how …

Campus Mental Health Service Use Among Female Survivors Of Sexual Violence: An Interpretative Phenomenological Analysis, Hannah Coffman

Graduate Theses and Dissertations

Description: Despite the increase in resources to address the alarming rates of collegiate sexual violence (SV), survivors consistently do not disclose or seek mental health treatment from campus supports (Halstead et al., 2017). The purpose of this study was to understand the lived experiences of women who survived SV during college.

Method: Seven women who experienced SV during college completed a series of two semi-structured interviews using a HIPAA-compliant, web-conferencing software (Seidman, 2013). The interviews were transcribed verbatim and analyzed using an interpretative phenomenological analysis (IPA) framework (IPA; Smith, 2004; Smith et al., 2009). A six-step data analysis procedure identified …

Towards A Large-Scale Intelligent Mobile-Argumentation And Discovering Arguments, Controversial Topics And Topic-Oriented Focal Sets In Cyber-Argumentation, Najla Althuniyan

Graduate Theses and Dissertations

User-generated content (UGC) platforms host different forms of information, such as audio, video, pictures, and text. They have many online applications, such as social media, blogs, photo and video sharing, customer reviews, debate, and deliberation platforms. Usually, the content of these platforms is provided and consumed by users. Most of these platforms, mainly social media and blogs, are often used for online discussion. These platforms offer tools for users to share and express opinions. Commonly, people from different backgrounds and origins discuss opinions about various issues over the Internet. Furthermore, discussions among users contain substantial information from which knowledge about …

Monte-Carlo-Based Analysis Of Traffic Flow For Urban Air Mobility Vehicles, Sara Ghayouraneh

Graduate Theses and Dissertations

The research conducted in this dissertation is focused on developing a simulation tool that can predict the traffic flow patterns of the Urban Air Mobility vehicles to alleviate some of the challenges related to their traffic management. First, an introduction to the concept of Urban Air Mobility is given, the usage of Automatic Dependent Surveillance-Broadcast systems for Urban Air Mobility vehicles is suggested and dynamic addressing concept is introduced as an answer to a part of air traffic management and address scarcity challenge for Urban air Mobility vehicles. Next, in order to simulate the traffic flow patterns of the Urban …

"A Rabble Rouser All The Time": Jim Johnson And The Politics Of Massive Resistance In Arkansas, Marie Cathryn Totten

Graduate Theses and Dissertations

James D. “Jim” Johnson was an Arkansas politician best known for his racism, commitment to segregation, and failed gubernatorial campaigns. Johnson makes appearances in some of Arkansas’ most notorious political moments in the 20th century. He campaigned for the Dixiecrats in 1948, led the state’s first major protest against integration in 1955, pushed Governor Orval Faubus to become a segregationist in 1956, and lost multiple elections in the 1960s. Although not victorious at the polls, Johnson had a tremendous influence on Arkansas politics in the middle of the 20th century. He made integration a viable political issue in the state …

Geolocation Of Monitoring Wells Using Small Unmanned Aircraft Systems, Joel Deyoung

Graduate Theses and Dissertations

Groundwater monitoring wells are commonly installed on a property as part of an environmental investigation to observe hydrological subsurface conditions, facilitate the collection of groundwater samples, and predict the flow of groundwater across a site. In addition to their installation, monitoring wells should be surveyed or mapped as accurately as possible. Traditional surveying techniques have employed the use of global navigation satellite systems (GNSS) technologies or other surveying equipment. A common surveying approach is to use real-time kinematic (RTK) GNSS to accurately measure the coordinates of each monitoring well on the site.In recent years, drones, or small unmanned aircraft systems …

Discipline Disproportionality Of Black Students With Disabilities: Principals' Perspectives, Wanda L. Van Dyke

Graduate Theses and Dissertations

The purpose of this study is to examine the problem of practice found in discipline disproportionality of Black students with disabilities in an urban school district with a majority Black student and teacher population. Through personal interviews with building level administrators, data was gained to determine common themes that impact discipline disproportionality of Black students with disabilities. A qualitative inquiry approach, in the form of a case study was used to determine principals’ perspectives about factors that may impact discipline disproportionality. Student disciplinary records were examined to verify disproportionality and investigate patterns and categories related to students with and without …

Latinos In The South: Community, Family, And Identity, José Tránsito Ayala Rodriguez

Graduate Theses and Dissertations

As Latinos have migrated at high rates to the U.S. South in the late 20th and early 21st centuries, the region has become known as a “new immigrant destination” and the “Nuevo South” yet political science research documenting the dynamics of Latino identity in the Nuevo South has been scarce. In this thesis I seek to understand the roles of Latino panethnic, U.S. (American) and Southern identity on factors informing the development of Latino community building. I use the 2016 Blair Center Poll to test social identity and family intimacy theories through a quantitative analysis of the effects of attachment …

Host-Parasite Interactions Within Food Webs, Adam Zvanut Hasik

Graduate Theses and Dissertations

Parasitism is one of the most common life history strategies employed in nature, yet the effects of parasites are often thought to be minimal, and the vast majority of studies fail to consider parasites and their effects on host organisms. This is likely a problem, as the magnitude of parasite-mediated effects on their hosts can be quite large. Additionally, the effects of parasites are known to extend beyond the host to affect other species interactions. I used a series of approaches to gain a more integral understanding of host-parasite interactions by studying (1) the effects of parasites on biotic interactions …

Of Biodiversity, Boundaries, And Distribution: The Myxomycetes Of The Philippines And Beyond, Sittie Aisha Bustamante Macabago

Graduate Theses and Dissertations

This dissertation contains a compilation of independently performed studies primarily focusing on the myxomycetes (plasmodial slime molds) from the Philippines and integrating local and worldwide data to demonstrate regional and global trends. The major themes include the following: (I) a review of the diverse group of spore-producing amoeboid protists, including the myxomycetes; (II-IV) diversity assessments in three different groups of islands in the Philippine archipelago; (V) mapping the myxomycetes found in the Philippines for databasing and analyzing the geocoded data; (VI) a study on regional boundaries, including the Philippines, using myxomycete species composition; and, (VII) creating a global species distribution …

Synthesis And Performance Testing Of Ecm Fiber Scaffolds, Cassandra Reed

Graduate Theses and Dissertations

The progression of regenerative medicine has advanced the treatment of multiple illnesses and injuries throughout the years. A good example of the benefits of this research is the work that has gone into volumetric muscle loss (VML), where more than 20% of the muscle is loss. Skeletal muscle makes up 40% of the human body so a loss of that size greatly diminishes the strength, the flexibility, physiology, and quality of life of the injured individual. For that reason, various techniques are used to counteract the loss of structure and innate cellular signaling in order to circumvent that from happening. …

Microfabrication And Electrochemical Characterization Of A Novel Su-8 Probe With An Array Of Individually Addressable Electrodes Suitable For Redox Cycling Experiments In Ultra-Small Volumes, Mahsa Lotfi Marchoubeh

Graduate Theses and Dissertations

Redox cycling is an electrochemical technique that utilizes closely spaced generator and collector electrodes to cycle reversible redox species between their oxidative states. With advantages in signal amplification, selectivity of species based on their electrochemical reaction mechanism, and limited or no background subtraction, this technique is well suited for selective detection of important electrochemically active molecules such as dopamine at basal or slowly changing levels.

Miniaturized medical devices have become an area of great interest for measurement of chemicals in limited volumes with low concentrations or in sensitive tissues. A probe on a polymeric SU-8 substrate with suitable dimensions and …

Analyzing The Mediating Effects Of Social Capital And Sense Of Community Between International Student’S College Sports Fan Identification And Acculturation, Kibaek Kim

Graduate Theses and Dissertations

According to the number provided by the International Institute of Education (IIE), there are over one million international students enrolled in the United States. Although the number of international students is increasing, the incremental rate started to decrease after reaching its peak in the 2017-2018 academic year. While previous studies focused on the role of leisure activities, such as physical activity participation, to analyze how international students can receive social support from their communities to better acculturate in the U.S., this study focused on the role of spectator sports on providing social support and its effect on international student’s acculturation. …