Digital Commons Network^™

Investigating Heterogeneity Of Hydraulic Conductivity And Its Influence On Groundwater Flow Dynamics Within A Saturated Riparian Buffer In Central Illinois, Joseph L. Awuku

Theses and Dissertations

The use of Saturated Riparian Buffers (SRBs) in agricultural settings as a means of reducing contamination of surface water and groundwater resources has gained popularity due to their trapping ability and solute removal (nutrient recycling) capacity. In light of SRB’s nutrient-trapping and removal ability, numerous studies have been conducted to characterize the effectiveness of SRBs. However, most studies on SRBs have paid minimal attention to heterogeneity of hydraulic conductivity (K) and groundwater flow dynamics within SRBs. This study investigated the heterogeneity in horizontal K and estimated the vertical groundwater-specific discharge (q_v) between the upper weathered and its …

Automorphism Groups Of N-Graded Vertex Algebras Associated With Cyclic Leibniz Algebras With Small Dimensions, Alexander M. Keene

Theses and Dissertations

A fundamental problem in the study of vertex (operator) algebras V is the determination of the group of (grading-preserving) N-graded vertex algebras associated with cyclic Leibniz algebras of dimensions 2 and 3 that were classified by C. Barnes, E. Martin, J. Service, and G. Yamskulna in [1].

In each case examined, investigation of the automorphism group relies on the key fact that the action of an automorphism σ is determined solely by its value at a single basis element b. Furthermore, we employ a result in [19] by H. Li and G. Yamskulna which states that we can determine the …

Centralized Deep Reinforcement Learning For Homogeneous Multi-Component Maintenance Optimization, Joseph W. Wittrock

Theses and Dissertations

This thesis explores an application of reinforcement learning (RL) in maintenance optimization. Recent advances in hardware-accelerated computation and deep learning have made RL a powerful tool for solving optimization problems which are too complex for traditional methods. Maintenance optimization involves improving the efficiency and effectiveness of maintenance activities through data-driven approaches, ultimately reducing costs and increasing asset availability. Making informed maintenance decisions is crucial to long-term sustainability.

A desirable maintenance policy maximizes a utility signal while minimizing the cost of maintenance. Techniques in sequential decision making such as dynamic programming (DP) and RL have found success in optimizing these maintenance …

Boys Build, Girls Glam: An Examination Of Adult Language Use In Informal Steam Education Settings, Alexandra Horton

Theses and Dissertations

Research on STEAM education has primarily focused on formal education settings such as schools, with more research needed in informal or non-traditional education settings. As children frequently engage with informal and non-traditional education settings, it is important to understand how we can transmit information in these settings to bolster and further the learning process and increase engagement. STEAM fields have been plagued by racial and gender inequities that have led to these groups being marginalized and excluded (Blair et al., 2017; Eaton et al., 2020; Martin, 2018; Martin & Phillips, 2019; Miller et al., 2018; Newall et al., 2018, Sheffield …

High Throughput, Solid Sample Analysis With Cone-Based Mass Spectrometric Ionization Sources, Emily J. Wiggins

Theses and Dissertations

The widespread presence of environmental and consumer-product contaminants (e.g. trace metals, opium alkaloids) has underscored the need for rapid, reliable, and high-throughput analytical techniques that are capable of handling complex solid samples. While traditional mass spectrometric (MS) methods tend to have high sensitivity and accuracy, they often require labor-intensive and time-consuming sample preparation steps that limit throughput and field applicability. This thesis investigates the use of 3D-Printed Cone Spray Ionization-Mass Spectrometry (3D-PCSI-MS) as an ambient ionization technique for the direct screening of contaminants from solid matrices, eliminating the need for traditional sample preparation and allowing for real-time analysis.

In …

Examining Mental Health Providers’ Differential Sensitivity To Youth And Caregiver Treatment Engagement Problems By Studying Clinical Decision-Making Behaviors, Wendy Chu

Theses and Dissertations

Clinical decision-making is a systematic process of collecting and using information to guide action regarding client care. Across frameworks of clinical decision-making, there is an emphasis on the assessment of a problem – which involves considering, identifying, and selecting a problem – as it directly informs intervention. In youth mental health services, problems related to treatment engagement or the ability to meaningfully participate in services are important to assess given their association with premature termination and poor outcomes. However, research suggests that assessment of engagement problems may be challenging, and one potential reason pertains to providers’ ability to assess across …

Navigating Leadership As A Black Woman In The United States Space Industry: An Exploration, Rogena Thurber

Theses and Dissertations

This phenomenological study explored the ontological perspectives and leadership experiences of Black women in the U.S. space industry, employing an intersectionality conceptual framework. The research aimed to understand how Black women navigated their paths to leadership at the intersection of gender and race within Predominantly White Institutions (PWIs) in the U.S. Space Industry (USSI).

Following a pilot phase to refine the research approach, eight one-hour, one-on-one interviews were conducted with Black women leaders from seven major USSI organizations in Southern California (LibGuides, n.d.). The study probed participants' leadership approaches, educational backgrounds, access to opportunities, and professional development experiences.

Emotional Intelligence …

Best Practices For Supporting Homeless Youth Achieve Academic Success, Abeni Elizabeth Carr

Theses and Dissertations

California has amassed a vast and growing population of homeless people. There exists a need to discuss the more significant generational impact that homelessness presents for students in secondary schools and to develop strategic planning to dismantle cyclical homelessness. Currently, there is an alarming trend in the number of youths who are experiencing homelessness. While much research in the past observed families experiencing housing instability, there are also burgeoning patterns of youth who are enrolled in high school, yet are becoming homeless due to running away from home. Both nationally and in California, youth are running away from their families …

Ai: A Path Forward In Education - Teachers’ Insights On Implementation, Challenges, And Future Innovations, Mercedes Cordoba Meeks

Theses and Dissertations

Artificial intelligence (AI) is a global phenomenon permeating the fabric of society and transforming the course of culture and commerce (Kishor et al., 2023; Moore, 2024). A review of the extant literature indicates that while many industries have seen significant innovations due to the infusion of AI, the field of education has witnessed a technological evolution inspired by AI-based tools and strategies (Bessen, 2018; W. M. Lim et al., 2023). Artificial Intelligence in Education (AIED) has a history that parallels the development of AI. AIED has shown steady growth and influence in educational programs around the world, with the growth …

Generative Ai's Impact On Student's Motivation And Well-Being In Online Graduate Programs: A Phenomenological Study Through Self-Determination Theory, Sohee Linda Lee

Theses and Dissertations

While higher education has increasingly embraced emerging technologies, limited research explores how adult learners at the graduate level navigate AI-driven feedback, content generation, and learning supports, particularly within online programs that require self-regulation and advanced academic rigor. To address this gap, this qualitative, phenomenological study examined how graduate students enrolled in online degree programs experience and interpret the use of generative AI (GenAI) tools, such as ChatGPT, in their coursework. Drawing on Self-Determination Theory (SDT), this study focused on how the use of GenAI tools may influence students’ perceptions on autonomy (volition and choice in tasks), competence (confidence in academic …

From Ink To Code, From Binary To Boundless Reality—Until All Returns To Emptiness, Weitong Sun

Theses and Dissertations

This thesis explores the entangled relationship between language, memory, and technology through the lens of immigrant experience. Moving from programming to visual storytelling, I investigate how dyslexia, bilingualism, and cultural displacement have shaped my ways of reading, writing, and coding.

Beginning with personal reflections on switching from computer science to art, I trace how code offered a form of clarity and expression where written language had once failed me. Yet as I ventured into real-time simulation and XR storytelling, I encountered new forms of mistranslation—where narratives dissolved, mutated, or resisted coherence altogether.

Through a series of experiments in code-driven art, …

The Cut Worm Forgives The Plow, August Neuscheler

Theses and Dissertations

The explorations in this thesis writing are centered on William Blake’s proverb “The cut worm forgives the plow.” It has been reinterpreted as an allegory of history and energy. A theory of their relation is proposed based on forgiveness, a theory that accepts the palimpsest of orders as evidence for the abundance of the present moment. The writing focuses on questions of proportionality, scale, archaeological screening methods, planar cutting, and a critique of entropy as grounds for this theory. Some of its subjects include the Statue of Liberty, Kate Raworth’s donut economic model, sashimi, triangulation, Joseph Beuys’ “7,000 Eichen,” semiconductors, …

Dosimetric Validation Of An Electron Monte Carlo (Emc) Algorithm For Small Cutouts And Extended Ssd’S: Assessing Emc In Small Field Dosimetry, Anil Basavaaraju

Theses and Dissertations

This thesis validates the accuracy and limitations of Electron Monte Carlo (eMC) simulations in Eclipse treatment planning systems for small-field electron dosimetry and extended source-to-surface distances (SSDs). Systematic measurements were performed using a microDiamond detector across various electron energies and field sizes. The study examines the discrepancies between measured and calculated (eMC) dose distributions, validating challenges due to lateral scatter disequilibrium and extended air gaps. Our findings provide systematic data for eMC dose calculations and demonstrate that eMC performs within clinical tolerances, with the ultimate goal of enhancing the precision and safety of radiation treatments.

Infinite Finite: A View On Human Progression Through Emergent Generative Systems, Fatima Abbas

Theses and Dissertations

Contemporary crises reveal an imbalance in human progression, prioritizing material advancement while neglecting ethical, compassionate, and spiritual dimensions. This thesis examines natural progression through the lens of emergence, where simple interactions produce complex outcomes. Analyzing natural patterns across different scales, from cosmic formations to neural interactions, underscores emergence's universal nature.

Within this context, Infinite Finite introduces a generative digital tool simulating emergence through iterative cycles of construction and deconstruction. Depicting a century of human progression informed by historical behaviors via simulated cellular interactions, the tool visually differentiates ethical from unethical progression. This is represented through ten data visualization tiles composed …

Development, Synthesis And Characterization Of Advanced Low- Cobalt And High-Nickel Cathode Materials For Lithium-Ion Batteries, Arjun Patel

Theses and Dissertations

This dissertation focuses on the improvement of structural and electrochemical stability of active materials for lithium-ion batteries. It explores the modification strategies to mitigate the issues related to Ni-rich cathode materials, along with the continuous production of cathode precursors using a slug flow reactor to improve the quality of the product.

The First part of the dissertation examines the effect of substitution of cobalt with aluminum and iron on the electrochemical stability of Ni-rich lithium nickel cobalt manganese oxide (NCM) materials. This study investigates how Al and Fe doping work and how they impact the performance and stability of these …

Investigating The Temperature Effects On Aedes Aegypti And Dengue Virus In Central Argentina: Perspectives From Mathematical Modeling, Morgan H. Jackson

Theses and Dissertations

Dengue virus (DENV) causes over 390 million infections and around 40,000 deaths worldwide each year. DENV is primarily transmitted by the mosquito Aedes aegypti, and both the life cycle of these mosquitoes and DENV transmission are significantly impacted by temperature. In the temperate region of Central Argentina, where dengue outbreaks first began in 2009, outbreaks only occur following new introductions of DENV from other regions. Due to the relationships between temperature and DENV and temperature and Ae. aegypti, the risk of an outbreak changes throughout the year. Here, we develop and analyze mathematical models for both mosquito population dynamics and …

Modeling Synergistic Effects Of Integrin And Tgf-Β Signaling In Epithelial Mesenchymal Transition, Prerak Thakkar

Theses and Dissertations

The induction of Epithelial Mesenchymal Transition (EMT) is initiated by a

number of protiens and growth factors, one of which is the profibrotic cytokine Trans-

forming Growth Factor β (TGF-β). Within the extracellular matrix (ECM), TGF-β

is found in a latent, inactive form bound to proteins such as fibronectin (FN). For

TGF-β to contribute to EMT induction, it has to be extracted from the latent com-

plexes into a soluble form. This soluble, activated TGF-β can then bind to receptors

on the cell membrane, which causes the transduction of signals that begin EMT. Re-

search has shown that the release …

Substrate Preference And Foraging Behavior Of Two Declining Warblers In Appalachian Shrublands, Samantha Fishman

Theses and Dissertations

Abstract Shrubland and early successional habitats (ESH) support a diversity of wildlife, including many declining songbirds. However, nonnative shrubs increasingly dominate these habitats, potentially altering habitat quality by influencing prey availability. Habitat quality can be assessed by observing foraging behaviors of songbirds and identifying preferred and avoided substrates as well as testing the predictions of optimal foraging theory; specifically that birds will maximize their energy gain relative to the costs. We examined foraging behaviors of Golden-winged Warblers (Vermivora chrysoptera; GWWA) and Chestnut-sided Warblers (Setophaga pensylvanica; CSWA) in ESH on private lands in Virginia with varying amounts …

Hafnium Oxide-Based Nanoheterostructures For Catalytic Radiosensitization And Enhanced X-Ray Radiotherapy, Marlen Dariela Calix Quezada

Theses and Dissertations

Orthovoltage X-ray beams are attractive for surface and intra-operative radiotherapy. Yet, their clinical utility is constrained by rapid attenuation and the limited dose that can be delivered without harming healthy tissue. High-Z hafnium oxide (HfO₂) nanoparticles can boost local energy deposition through the photoelectric effect, while catalytic surface defects accelerate water radiolysis. Harnessing both mechanisms in a single nano-heterostructure could enable potent radiosensitization at diagnostic-range energies.

This thesis develops and evaluates HfO₂-based nanoheterostructures, both bare and Au-decorated, as catalytic radiosensitizers.

Two types of HfO₂ were evaluated, one was synthesized following a specific route and the …

An Exploration Of The Relationship Between School Counselor Access And Latine Students’ College-Going Behaviors, Kristen Tuxbury

Theses and Dissertations

This study examined the relationships between school counselor access and Latine students’ college-going behaviors using data from the High School Longitudinal Study of 2009 (HSLS:09). The study was guided by critical race theory and Yosso’s community cultural wealth model (2005). Binary logistic regression models, Chi-square tests of independence, and descriptive statistics were used to explore the associations between school counselor access, Latine student college-going behaviors, and caregiver expectations. The findings show stronger associations between caregiver expectations and Latine student college-going behaviors than school counselor access. Additionally, findings provide evidence that experiences of oppression are likely barriers to Bachelor’s degree programs …

Optimal Data Splitting Methods, Sujay Mudalgi

Theses and Dissertations

In predictive modeling, effective data splitting is crucial for creating statistically representative training and validation sets. The state-of-the-art data splitting methods are based on minimizing the energy distance between the split subsets. However, there are a number of limitations in the existing methods, which this dissertation aims to address. First, the existing methods were computationally inefficient. Thus, Chapter 2 proposes a method to scale up these approaches for big data. Here, we introduce scalable Twinning (s-Twinning), which significantly improves the execution speed of data splitting without sacrificing accuracy. Second, the existing methods did not consider the predictive relationship in the …

Machine Learning Models Leveraging Patient-Similarity And Clinical Temporality For Disease Prognoses, Ahmad F. Al Musawi

Theses and Dissertations

Electronic Health Records (EHRs) constitute a comprehensive and high-dimensional repository of clinical data, encompassing a wide array of patient-level information such as diagnoses, procedures, medications, laboratory results, and unstructured clinical narratives. These data hold immense potential for advancing predictive modeling in healthcare, including tasks such as disease progression modeling, hospital readmission prediction, and length of stay (LoS) estimation. However, the intrinsic complexity of EHR data—manifested in its heterogeneity, sparsity, and temporal dynamics—poses significant analytical challenges that limit the generalizability and interpretability of conventional machine learning models. Recent methodological advancements in deep learning and graph-based learning, particularly Graph Neural Networks (GNNs), …

Visible Modulation Of Epsilon Near Zero Materials, Jonathan M. Weber

Theses and Dissertations

While Epsilon-Near-Zero materials have offered many benefits from their introduction to the field of nonlinear optics, those materials have also narrowed the range of wavelengths often studied. With reliable and proven enhancements to light-matter interaction in the ENZ region, many researchers have had little reason to extend the spectrum measured in experiments. The purpose of this work is to measure the intensity dependent refractive index of Indium Tin Oxide across a broad spectral range, from ultraviolet to near infrared, to improve the understanding of semiconductor nonlinearities far from Lorentz and Drude resonances. Furthermore, the visible region is naturally low-loss in …

Intervertebral Lateral Bending Moment Differences In The Lumbar Spine Of Baseball Pitchers Across Throwing Velocities, Justin Humenay

Theses and Dissertations

Introduction Baseball pitching imposes substantial mechanical demands on the lumbar spine, a crucial link in the kinetic chain responsible for transferring energy from the lower body to the upper extremity. While increased pitch velocity is associated with greater trunk forces the specific intervertebral loading patterns during high-velocity pitching remain unclear. This study investigates differences in lateral bending moments across lumbar spinal segments between collegiate pitchers throwing at high versus low velocities.

Methods Twenty right-handed collegiate pitchers were divided into two groups: high-velocity (n = 10, 90.3 ± 1.6 mph) and low-velocity (n = 10, 81.6 ± 1.1 mph). Motion capture …

Periodic Trends In The Electronic And Magnetic Structure Of Superatomic 3d Transition Metal Chalcogenide Clusters, Gabriel Bohannon

Theses and Dissertations

We have systematically investigated the electronic structure of octahedral transition metal chalcogenide clusters, TM₆S₈(CO)₆, in which the transition metal atoms are from the 3d series in order to identify if periodic properties emerge. We were motivated by the identification of closed electronic shells with electron counts of 96, 100 and 114 in similar clusters from the 4d and 5d transition metal series. Further motivation was the finding of a dual-shell closing in the Fe₆S₈(CN)₆^5- cluster. This cluster is stabilized with a large spin magnetic moment due to the …

Modeling Vaccination Strategies And Intervention Impacts On Infectious Disease Dynamics, Elizabeth B. Amona

Theses and Dissertations

This dissertation explores how mathematical and statistical modeling can inform vaccination strategies and evaluate the impact of interventions during infectious disease outbreaks. Motivated by the challenges observed during the COVID-19 pandemic, the research integrates compartmental modeling, Bayesian inference, and agent-based simulation to assess policy effectiveness and disease control across varying contexts. The first study develops a SEIRDV model that incorporates government interventions and vaccination rollout to examine COVID-19 dynamics in Qatar. A Bayesian approach is used to estimate parameters and compute time-varying transmission rates. The model captures shifts in transmission following policy changes and quantifies the reduction in deaths attributable …

Automated Treatment Planning Framework For Cervical Cancer In Brachytherapy, Suman Gautam

Theses and Dissertations

Brachytherapy (BT) is a critical treatment modality for cervical cancer that delivers ionizing radiation directly to the tumor using intracavitary (IC) and/or interstitial (IS) applicators. In high dose-rate (HDR) BT, a remote afterloader guides the radioactive source to specific dwell positions for defined durations, known as dwell times, allowing for a conformal dose to the tumor while minimizing exposure to surrounding organs at risk (OAR). However, due to the inherent nature of ionizing radiation, some dose to OARs is unavoidable, creating a fundamentally conflicting objective in treatment planning: maximizing tumor coverage while minimizing OAR dose. This characterizes the problem as …

Plasmon-Assisted On-Chip Integration Of Quantum Emitter For Scalable Quantum Networking, Samprity Saha

Theses and Dissertations

In recent decades, quantum theory has sparked a revolutionary outlook on our long-standing perception of information processing and communication technologies. Photon-based quantum systems, relying on single photons governed by quantum mechanics, hold immense promise for quantum networks due to their resilience against decoherence and fast propagation speeds. However, challenges persist in realizing practical quantum networks, including the need for scalable, robust, and cost-effective quantum light. To address these challenges with classical photonic concepts, this thesis focuses on a plasmon-assisted approach for on-chip integration of single-photon sources. The study aims to develop a scalable solution for integrating quantum emitters on-chip, leveraging …

A Mixed Methods Study: High School Teachers’ Perspectives On Incorporating Mindful Artmaking In Their Classroom As A Mental Health Resource, Sherry A. Bosarge

Theses and Dissertations

Mental health concerns and the need for mental health resources for high school students continue to rise in Virginia. Some of the reported benefits to the current mental health services and resources offered in Virginia schools are increased academic outcomes, attendance, and positive behaviors. The reported barriers to current mental health services and resources are lack of participation, lack of training, time constraints, funding, and resources. This explanatory sequential mixed methods study examined high school teachers’ perspectives on the benefits and barriers to incorporating mindful artmaking in their classrooms as a mental health resource at a local high school. This …

Brute Gamification, Catherine Chen

Theses and Dissertations

Digital platforms are surreptitious structures that gamify the ways in which we engage and exchange. They dictate every step of our journeys even as we navigate onward with a sense of absolute agency. The harder that we try to win, the more the platform will win!

In Brute Gamification, I employ image-based installation and performance to unravel the terms and conditions with which these platforms dictate our lives. A literal platform supports a series of image-games, all of which are about to end in a draw. Through prescribing the user to a designated path to focus on this non-ending as …