Digital Commons Network^™

Recent Advances In Magnetic Feˣ⁺/Tio₂ Microfibers For Wastewater Treatment As Climate Change Mitigation, Misriani Misriani, Yang Tian, Z. Ryan Tian

Chemistry & Biochemistry Faculty Publications and Presentations

Chemical dyeing and finishing processes used in the clothing and textile industries are among the main contributors that can increase the impact of climate change. Photocatalysis using nanosized titanium dioxide (TiO₂) has been continuously developed as a promising technology for purifying dye wastewater into simpler and environmentally friendly components. In addition, the decoration of iron cations (Fe²⁺) and (Fe³⁺) increases the reusability of the photocatalyst due to their magnetic properties, which are easy to collect for the recycling process. Magnetic Fe^x+/TiO₂ microfibers have been successfully prepared using a hydrothermal method using …

A Two-Part Validation Study Of The Sexual Minority Identity Emotion Scale, Henrietta Kadi Tettey-Tawiah

Graduate Theses and Dissertations

A number of existing studies indicate that there is some correlation between pride and shame and various behavioral health outcomes like anxiety, depression, and self-harm in the general population. Research also confirms that this relationship is true among sexual minorities as well. This study sets itself up to interrogate this assertion vis-à-vis sexual minority adolescents (SMAs). Consequently, confirmatory factor analysis (CFA) and differential item functioning (DIF) detection analysis were performed on the 35-item Sexual Minority Identity Emotion Scale (SMIES) for SMAs. A tree-based modeling technique, specifically conditional inference trees (CIT), was then employed to explore and make predictions about the …

Hierarchical Spatial Abundance Models For Migratory Shorebirds, Md Shahbaz Alam

Graduate Theses and Dissertations

Predicting the distribution and abundance of migratory shorebirds is crucial for effective conservation planning. This research applies hierarchical spatial models to predict counts and spatial variations of three shorebird species: Semipalmated sandpiper (sesa), Ruddy turnstone (rutu), and Whimbrel (whim). Different versions of the Poisson, Negative Binomial, and Hurdle regression models are employed to tackle specific data characteristics, such as overdispersion and excess zeros. Model comparisons are performed in terms of likelihood measures and cross-validation. The Hurdle model for sesa and rutu and the Negative Binomial model for whim effectively captured spatial patterns, highlighting potential hotspots. Mean predictive count further emphasized …

Cover-Crop Effects On Near-Surface Soil Properties Over Time In The Lower Mississippi River Valley, Cooper Fanning

Graduate Theses and Dissertations

Human population growth and climate change are present stressors that continue to put pressure on current agricultural production systems, where typical row-crop agricultural practices can negatively impact soil health. Extensive use of cover crops (CC) to increase soil health remains widely unrealized. Soil health in Arkansas is a major concern for sustaining agricultural output, therefore research into CC implementation across Arkansas to maintain or improve soil health is needed. The objective of this study was to evaluate the effects of CC (i.e., with and without CC) across various physical, hydraulic, biological, and chemical soil indicators in the Lower Mississippi River …

Leveraging Machine Learning And Stochastic Programming To Address Vaccine Hesitancy In Public Health Resource Allocation, Hieu Trung Bui

Graduate Theses and Dissertations

Infectious disease outbreaks highlight the urgent need for effective strategies to distribute vaccines and allocate critical healthcare resources to contain the disease and reduce its negative impacts on the population. Managing these allocations is a significant challenge, especially in marginalized communities facing uncertainty in healthcare demand and logistical constraints. This dissertation addresses these challenges by investigating factors that influence dynamic changes in vaccine hesitancy (VH) and its implications for disease spread and healthcare resource demand. It develops optimization models for vaccine distribution and resource allocation under uncertainty, validated with data from the COVID-19 pandemic in the U.S. The first study …

Developing Catalysts For The Hydrolysis Of Glycosidic Bonds In Oligosaccharides Using A Spectrophotometric Screening Assay, Susanna Striegler

Chemistry & Biochemistry Faculty Publications and Presentations

In a proof-of-concept study, a method for the empirical design of polyacrylate gel catalysts with the ability to cleave 1→4 α-glycosidic bonds in di- and trisaccharides was elaborated. The study included the synthesis of a 300-gel member library based on two different cross-linkers and 10 acrylate monomers, identification of monomodal gels by dynamic light scattering, and a 96-well plate spectrophotometric screening assay to monitor the hydrolysis of chromophore-free maltose into glucose units. The composition of the matrix of the most efficient catalysts in the library was found to enable CH−π, hydrophobic, and H-bond accepting interactions during the hydrolysis as typically …

Untapped Potential? Understanding The Paraeducator-To-Teacher Pipeline And Its Potential For Diversifying The Teacher Workforce, Andrew M. Camp, Gema Zamarro, Josh B. Mcgee

Education Reform Faculty and Graduate Students Publications

Paraeducators are among the largest categories of public education employees and are increasingly seen as a pool of potential teachers. However, little is known about paraeducator-to-teacher transitions. Using statewide administrative data, we show that while paraeducators may be more racially/ethnically diverse than the teacher workforce, Black and Hispanic paraeducators are less likely than White paraeducators to transition into teaching. We additionally show that teachers with paraeducator experience are similarly effective to teachers without paraeducator experience. Lastly, we use simulations to show that the potential for the paraeducator-to-teacher pipeline to diversify the teaching profession may be limited unless they are highly …

Impacts Of High-Frequency Operation On Magnetics And Performance On Isolated Power Electronic Converter Design, David Arturo Porras Fernandez

Graduate Theses and Dissertations

The pursuit of high-power density and high switching frequency is a central theme in the advancement of power electronic converters. While these parameters offer significant benefits in terms of compactness and performance, they also introduce challenges related to efficiency and thermal management. This doctoral dissertation aims to provides a design framework to analyze the implications of high-frequency operation (> 100 kHz) on magnetics design and performance in power electronic converters, particularly when integrating silicon carbide (SiC) power modules. It examines the advantages and disadvantages of high-frequency operation and delves into its effects on the performance of the converter, focusing on …

Investigating The Applications Of Peps To The Measurement Of The Stabilities Of Staphylococcal Nuclease (Stw) And Human Acidic Fibroblast Growth Factor (Hfgf1), Motolani Omolade Matthew

Graduate Theses and Dissertations

This dissertation presents a detailed investigation into the applications of Protein Equilibrium Population Snapshot H/D Exchange Electrospray Ionization Mass Spectrometry (PEPS-H/D exchange or PEPS) method. This method is based on protein equilibrium unfolding, and its fundamental capability is to capture a "snapshot" of the protein's state, allowing us to monitor the ratio of the unfolded to folded populations at different chemical denaturant concentrations. First, to increase the accuracy of PEPS data analysis for assessing protein stability, the traditional linear extrapolation method (LEM) was replaced. Instead of using LEM, which calculates free energy change based on the peak ratio of unfolded …

Partial Immunity To Mycoplasma Gallisepticum After An Initial Infection Is Long-Lasting And Reduces Transmission In Flocks Of Canaries, Madeline Sudnick

Graduate Theses and Dissertations

Pathology during a second infection can be influenced by immunity and an increase in resistance or tolerance of individuals. Population-level differences in the ability to maintain immunity can lead to contrasting survival outcomes between groups and determine how future outbreaks will spread. However, long term wildlife disease surveillance can be challenging due to lack of infrastructure and host-pathogen specific tests. Calculating disease transmission likelihood requires understanding individual-level heterogeneity in pathology and behavior, and there is limited knowledge in understanding how populations in different stages of an epidemic will transmit disease. In Chapter I, we aim to help fill a gap …

Parallel Degree Planning In The Pursuit Of Academic Success For Pre-Nursing Students In A Competitive Entry Baccalaureate Nursing Programs, Elizabeth L. Mckinley

Graduate Theses and Dissertations

This study sought to understand the student perceptions of parallel academic degree planning for the competitive entry undergraduate Nursing program at a case study university. Parallel degree planning is a relatively new term of alternative curricular planning. The qualitative study includes nine students and their experiences in planning for their intended major while simultaneously planning courses that meet another major or degree program, and understanding how parallel degree planning aided their retention and student satisfaction as well as their academic advisor interaction. The study was completed at a research university where the Nursing program has a very lower acceptance rate, …

An Exploratory Multiple Case Study Of Special Education Transition Program Structures In Virtual Public Charter Schools, Krystle Merry

Graduate Theses and Dissertations

This dissertation research is an exploratory multiple-case study of special education transition program structures in three virtual public charter schools in a southern state in the United States. Virtual public charter schools are extensions of public school systems or districts that are required to comply with state and federal-mandated special education transition services to ensure students with disabilities receive a Free Appropriate Public Education (FAPE) under the Individuals with Disabilities Education Act (IDEA, 2004). This study aims to explore transition Program Structures within the Taxonomy for Transition Programming 2.0 (Kohler et al., 2016) at the systemic level based on the …

Influence Of Invasive Species, Drought, And Stream Permanence On Stream Crayfish Species With A Focus On The Imperiled Mammoth Spring Crayfish (Faxonius Marchandi), Leah Marie Bayer

Graduate Theses and Dissertations

Freshwater crayfish constitute one of the most-threatened taxonomic groups in North America. Invasion by other crayfish species as well as habitat degradation through alteration of natural flow regime are two of the most prominent threats to crayfish persistence. Additionally, extreme weather events like droughts can amplify threats posed by other stressors on crayfish populations and are expected to increase in frequency, magnitude, and/or duration in the future, which may negatively influence narrow-ranged endemic crayfish populations typical of the Southeast. The Mammoth Spring Crayfish, Faxonius marchandi, is a narrow-ranged endemic that occurs in the Spring River drainage of Arkansas and Missouri …

Effects Of An Interdependent Group Contingency On Classroom Behavior And Teacher-Student Relationships For Students With Behavioral Support Needs: An Initial Investigation Of Cw-Fit Ms Tier 1 In Inclusive Secondary Settings, Nancy Ruth Young

Graduate Theses and Dissertations

A wide body of literature has documented the disproportionality in exclusionary discipline rates (Gregory et al., 2010; Losen et al., 2015; Office of Special Education Programs, 2020; Skiba, 2014; Welsh & Little, 2018). Students with disabilities or other minority backgrounds are removed from their classrooms at higher rates than their peers (Losen & Gillespie, 2012; Office of Special Education Programs, 2020). Such punitive practices have been associated with negative outcomes for the most at-risk youth. Thus, educational stakeholders have begun to move away from these punitive practices toward more positive behavior management methods. This study sought to examine the impact …

Feasibility Study For The Application Of A Solar Powered Absorption Chilling System For Cooling Poultry Houses In Northwest Arkansas, Matthew James Kelly

Graduate Theses and Dissertations

This paper investigates the economic feasibility of utilizing a solar-powered absorption chiller to provide cooling for poultry houses in northwest Arkansas. An existing thermodynamic model of a poultry house was modified to account for cooling. A simulation was performed using actual weather data from Fayetteville, Arkansas for 26 flocks of broilers at four cooling capacities for the 2020, 2021, and 2022 calendar years. Based on the simulation, the savings from reduced electricity use for ventilation and the cost of the required absorption chiller and solar thermal array for an 8-house farm were calculated. While providing cooling was found to reduce …

Struvite Effects On Greenhouse Gas Emissions From Flood- And Furrow-Irrigated Rice In The Greenhouse, Chandler Arel

Graduate Theses and Dissertations

Over time, as the influences of climate-change and declining, mineable, global phosphorus (P) reserves begin to impact agricultural production systems, alternative fertilizer sources and management practices, such as struvite (MgNH₄PO₄ · 6H₂O) and furrow-irrigation, will be necessary to accommodate nutrient and water demands. The precipitation and use of struvite as a fertilizer-P source could reduce environmental damages caused by nutrient-rich wastewater streams, supplement domestic P supply, and improve the sustainability of flood-, and furrow-irrigated rice production by reducing greenhouse gas emissions. The study of struvite from both chemical and electrochemical precipitation processes is well documented, …

Student Perceptions And Academic Performance When Taught With Multiple Active Learning Methods In A High Enrollment Undergraduate Human Physiology Course, Kate Ireton Walker

Graduate Theses and Dissertations

When instructing very large groups of students in science, it can be difficult to engage all students in the content and measure their understanding. A major unaddressed challenge in science instruction is how specifically to design and implement strategies that engender active learning particularly in high-enrollment undergraduate courses. Active learning, which represents a diverse set of strategies, may include student engagement as part of instruction through discussions, active movement, and application (Bernstein, 2018; Cavanagh, et al. 2016; Michael, 2006 & Wilke, 2003). This study was designed to provide data addressing the gap in the literature regarding how the continual implementation …

Neural Interactions In Bottom-Up Communication, Prashant Chama Raju

Graduate Theses and Dissertations

The visual system’s remarkable ability to process vast amounts of sensory information rapidly and accurately is fundamental to cognitive neuroscience. This study investigates a key aspect of this capability: the compartmentalization of information into feature-specific subspaces during bottom-up communication. My primary question was: does Canonical Correlation Analysis (CCA) reveal a subspace that encodes color and direction of moving dot stimuli? I found that the first canonical component (CC1) does an excellent job decoding the stimuli, despite being one-dimensional while the stimuli were drawn from a two-dimensional space (red-green and up-down plane). I demonstrate that motion features are processed within distinct …

Tuning Electronic Transport And Magnetic Properties Of Layered Magnetic Materials, Md Rafique Un Nabi

Graduate Theses and Dissertations

Two-dimensional magnetic materials (2DMMs) have gained significant interest due to their potential for novel physical phenomena and device applications. Mn_2-xZn_xSb, with its tunable magnetic properties and stable tetragonal layered structure, offers a rich platform for exploring these phenomena. The introduction of Zn into the Mn₂Sb lattice efficiently tunes magnetic and electronic properties, making it a compelling candidate for high-performance spintronic devices.

With this motivation, we synthesized Mn_2-xZn_xSb (0 ≤ x ≤ 1) single crystals using a flux method. Mn2Sb exhibits ferrimagnetic order below 550 K with antiparallel spins aligned along …

Quantum Modeling & Experimental Studies Of Radical Chemistry, Justin Michael Barrett

Graduate Theses and Dissertations

This work describes two projects centered around radical chemical mechanisms. The first investigation generalized the utility of a C-N bond homolysis followed by a [1,3] – rearrangement synthetic strategy found possible in N-alkylated thiazole & benzothiazole species onto analogous systems. Computational investigation guided the inquiry on structurally analogous systems that would favor a radical, [1,3] – rearrangement. Herein, we describe the implementation of that mechanism to transform Breslow Intermediate-like substrates into tertiary alcohol and amide products under facile conditions. We confer on the proficiency of this strategy with 2-pyridinemethanol and the problematic implementation with 2-(aminomethyl)pyridine. The second investigation solved a …

Controls On The Development Of Hummocky Topography On Debris-Covered Glaciers, Ryan M. Strickland

Graduate Theses and Dissertations

Rock debris covers many glaciers in Earth’s highest mountains and the debris impacts glacier response to changes in climate. Interactions between debris, drainage, glacier dynamics, and climate produce contrasts in melt rates that cause debris-covered glaciers to develop complex, hummocky topography. Contrasts in melt rate produce thousands of hills–hummocks–and depressions. Ponds and ice cliffs often form in the depressions. Although ponds and ice cliffs occupy only a small fraction of the surface, they account for nearly half of glacier melt. Understanding the processes that control the development of hummocky topography is key to predicting the evolution of debris-covered glaciers. In …

An Optimization-Based Monte Carlo Method For Estimating The Two-Terminal Survival Signature Of Networks With Two Component Classes, Daniel B. Lopes Da Silva, Kelly M. Sullivan

Industrial Engineering Faculty Publications and Presentations

Evaluating two-terminal network reliability is a classical problem with numerous applications. Because this problem is #𝖯-Complete, practical studies involving large systems commonly resort to approximating or estimating system reliability rather than evaluating it exactly. Researchers have characterized signatures, such as the destruction spectrum and survival signature, which summarize the system's structure and give rise to procedures for evaluating or approximating network reliability. These procedures are advantageous if the signature can be computed efficiently; however, computing the signature is challenging for complex systems. With this motivation, we consider the use of Monte Carlo (MC) simulation to estimate the survival signature of …

Risk Of Invasive Waterfowl Interaction With Poultry Production: Understanding Potential For Avian Pathogen Transmission Via Species Distribution Models, Reilly T. Jackson, Percival Matzinger Marshall, Chris R. Burkhart, Julia Schneck, Grant Kelly, Caleb P. Roberts

Biological Sciences Faculty Publications and Presentations

Recent outbreaks of highly pathogenic avian influenza have devastated poultry production across the United States, with more than 77 million birds culled in 2022–2024 alone. Wild waterfowl, including various invasive species, host numerous pathogens, including highly pathogenic avian influenza virus (HPAIV), and have been implicated as catalysts of disease outbreaks among native fauna and domestic birds. In major poultry-producing states like Arkansas, USA, where the poultry sector is responsible for significant economic activity (>$4 billion USD in 2022), understanding the risk of invasive waterfowl interactions with domestic poultry is critical. Here, we assessed the risk of invasive waterfowl-poultry interaction …

How To Situate High School Student Part-Time Work Trends: An [Incomplete] Empirical Glance, Michael Heise

Arkansas Law Review

Recent federal warnings about increases in child labor law violations coincide with various state efforts to dilute child labor protections. This Article confines itself to the array of outcomes attributable to lawful part time work performed by non-trafficked, full-time, U.S. high school students. This Article sets out to develop two modest and separate—though related—claims. The first claim is that clear and reliable answers do not emerge for such basic policy questions as, for example, whether student part-time work during high school constitutes a penalty or, instead, confers rewards to students. This Article’s second claim is methodological. Specifically, much of the …

Revealing Structural Evolution Of Nickel Phosphide-Iron Oxide Core–Shell Nanocatalysts In Alkaline Medium For The Oxygen Evolution Reaction, Ryan H. Manso, Jiyun Hong, Wei Wang, Prashant Acharya, Adam S. Hoffman, Xiao Tong, Feng Wang, Lauren F. Greenlee, Yimei Zhu, Simon R. Bare, Jingyi Chen

Chemistry & Biochemistry Faculty Publications and Presentations

Metal phosphide-containing materials have emerged as a potential candidate of nonprecious metal-based catalysts for alkaline oxygen evolution reaction (OER). While it is known that metal phosphide undergoes structural evolution, considerable debate persists regarding the effects of dynamics on the surface activation and morphological stability of the catalysts. In this study, we synthesize NiP_x-FeO_x core–shell nanocatalysts with an amorphous NiP_x core designed for enhanced OER activity. Using ex situ X-ray absorption spectroscopy, we elucidate the local structural changes as a function of the cyclic voltammetry cycles. Our studies suggest that the presence of corner-sharing octahedra in the …

Shoreline Barriers May Amplify Coastal Groundwater Hazards With Sea-Level Rise, Xin Su, K. M. Befus, Michelle A. Hummel

Geosciences Faculty Publications and Presentations

Subsurface barriers have been proposed to protect coastal aquifers from sea-level rise induced seawater intrusion, but the potential for groundwater emergence near subsurface barriers remains unknown. Here, we investigated how emergence changes groundwater flow conditions and influences the protective performance of subsurface barriers with sea-level rise. We tested the subterranean consequences of sea-level rise for cutoff walls and subsurface dams with cross-shore groundwater flow and salt transport models, investigating how barrier design, aquifer properties, and hydrological conditions control the potential for emergence, groundwater partitioning at the barrier, and seawater intrusion with sea-level rise. We find that most subsurface infrastructure cannot …

Evaluating Artificial Intelligence On The Efficacy Of Preference Assessments For Preservice Speech-Language Pathologists, Brenna Griffin, Elizabeth R. Lorah, Christine Holyfield, Nicolette Caldwell, John Nosek

Curriculum and Instruction Faculty Publications and Presentations

Individuals with intellectual and developmental disabilities (IDD) face many barriers to meaningful inclusion, including limited language and communication skills. Professionals, such as speech-language pathologists (SLPs), can provide personalized instruction to promote skill development and inclusion. Providing opportunities for individuals to express preferences and choice, such as the multiple stimulus without replacement preference assessment (MSWO; DeLeon & Iwata 1996), within these programs, further increases skill acquisition and social interaction. However, limitations in professionals’ knowledge and skills in performing assessments can be another barrier to meaningful inclusion for individuals with IDD and traditional training methods can be challenging and time consuming. …

Learning From Oversampling: A Systematic Exploitation Of Oversampling To Address Data Scarcity Issues In Deep Learning- Based Magnetic Resonance Image Reconstruction, Ibsa Kumara Jalata, Reeshad Khan, Ukash Nakarmi

Computer Science and Computer Engineering Faculty Publications and Presentations

Data acquisitions in Magnetic Resonance Imaging (MRI) are inherently slow due to sequential acquisition protocol. Image reconstruction from under-sampled data is posed as an inverse problem in traditional model-based learning paradigms. Recent data-centric learning frameworks such as deep learning (DL) frameworks are data hungry, and demand a large, labeled training data sets. To address the lack of large training datasets, in MRI reconstructions, researchers approach the problem in two ways: (1) unsupervised method where the model is trained without the presence of fully sampled data. (2) using a method that efficiently use the limited dataset for training purpose. In this …

Valuing Trans Lives After Suicide: Rituals Of Commemoration In Digital Social Media Culture, Joe Edward Hatfield

Communication Faculty Publications and Presentations

In 2014, a trans teenager named Leelah Alcorn posted a suicide letter to her public Tumblr account. Almost a decade later, in 2023, Eden Knight, another young trans woman, posted a suicide letter to her public Twitter account. Both suicide letters went viral and inspired memorial hashtags on the platforms where they initially circulated. In this article, I identify similarities between the cases, conceptualizing both as rituals of commemoration aimed toward restoring value to trans lives lost too soon. My analysis shows how ordinary users leverage the connective affordances embedded within popular social media platforms to sustain structured, value-laden acts …

The Impacts Of Dimensionality, Diffusion, And Directedness On Intrinsic Cross-Model Simulation In Tile-Based Self-Assembly, Daniel Hader, Matthew J. Patitz

Computer Science and Computer Engineering Faculty Publications and Presentations

Motivated by applications in DNA-nanotechnology, theoretical investigations in algorithmic tile-assembly have blossomed into a mature theory. In addition to computational universality, the abstract Tile Assembly Model (aTAM) was shown to be intrinsically universal (FOCS 2012), a strong notion of completeness where a single tile set is capable of simulating the full dynamics of all systems within the model; however, this construction fundamentally required non-deterministic tile attachments. This was confirmed necessary when it was shown that the class of directed aTAM systems, those where all possible sequences of tile attachments result in the same terminal assembly, is not intrinsically universal (FOCS …