Digital Commons Network^™

Emergence: Social Movements, Law Enforcement, And Defending The Sanctity Of Life, Diana Elizabeth Aroche

Doctoral Dissertations

This study examines the aftermath of national social movements advocating for police reforms and accountability, with San Francisco emerging as a pivotal city at the forefront of criminal justice and policing transformations. Rebuilding community trust and implementing substantive police reforms aimed at preserving lives has proven to be a formidable challenge. The convergence of interests among all stakeholders, driven by a shared commitment to dismantling institutional racism and implementing reforms that fostered trust with communities of color and law enforcement, played a pivotal role.

A significant aspect of this reform process has been the development of social movement convergence, where …

Accessible Technology For All: A Content Analysis Of Ux Design In Mobile Websites And Applications, Christine A. Franco

Doctoral Dissertations

More and more, digital technologies are becoming the fabric of everyday life, imbuing almost every aspect of modern society. With an increasing reliance on technology to complete essential tasks for school, work, communication, health, finance, and more, there remain barriers to accessing these tools. These barriers are not just represented by the digital divide, the haves and have-nots, but in the myriad ways in which the technologies we use every day are difficult to use, complex, or simply inaccessible. This research study investigates the factors that impact the accessibility of technology, specifically for individuals with either temporary, situational, or permanent …

A Pathway To Light-Induced Assembly Of Polymer Nanoparticles, Anna Huebner

Doctoral Dissertations

Since the late 1980’s tissue engineering has become an important field in regenerative medicine. Tissue engineering aims to create scaffolds designed to mimic the extracellular matrix (ECM) of human tissue, which is a complex, heterogeneous system. While there are a variety of approaches for scaffold fabrication, it is difficult to mimic the heterogeneity of the natural ECM. NH BioMade proposed a tissue engineering scaffold design to address these limitations, where multi-lobed particles can be 3D-printed to form a scaffold, providing heterogeneity in pore size by the incorporation of different-sized multi-lobed particles. In order for particles to be 3D printed into …

Aspects Of Mirror Symmetry For Non-Fano Toric Varieties, Michael John Samuel Lathwood

Doctoral Dissertations

Correlation functions in the topological A-model can be computed with open Gromov-Witten invariants whereas the mirror topological B-model admits a simpler description in terms of period integrals. We first review preliminary material in Chapter 1. Then in Chapter 2 we use tropical geometry to construct the Duistermaat-Heckman measure for non-Fano toric varieties. This allows one to compute the asymptotic terms of period integrals. In Chapter 3 we solve the generalized Picard-Fuchs system for the Hirzebruch surfaces, and hence compute periods to all orders of the mirror complex structure moduli. Near the large complex structure limit point, we use toric degenerations, …

Mathematical Explorations Into The Inner Workings Of Neural Networks, Xiang Li

Doctoral Dissertations

Neural network applications are everywhere in our lives today. We can now design and train large neural networks with billions of parameters for a multitude of complex tasks. However, it is still extremely challenging for us to explain the theoretical underpinnings that have led to the successful use of neural networks for a wide range of applications. This dissertation focuses on the mathematical foundations of neural networks.

In Chapter 2, we investigate the error function of fully connected neural networks with the rectifier linear unit (ReLU) activation functions. We prove that for any linear neural network with a single hidden …

Essays On Labor, Immigrants, And Inputs, Andrew Clina

Doctoral Dissertations

In my dissertation, I concentrate on the broad topic of trade and its effects on domestic markets, employing both empirical analysis and theoretical frameworks. This study delves into two primary facets of trade's influence: labor and production. While the impact of trade with China on labor markets on manufacturing employment is well studied, I contribute to existing literature by investigating its effects on STEM (Science, Technology, Engineering, and Math) occupations. Despite considerable attention to STEM education, there is little research on these specific occupations. I extend this analysis in my second chapter by examining how immigrants are affected differently from …

Differential Roles Of Replication Protein A Large Subunit Paralogs In Dna Damage Repair, Ian Mills

Doctoral Dissertations

DNA damage is a constant threat for all organisms. The most severe form of DNA damage is a double-strand break (DSB) that can have disastrous consequences to the cell including genome truncation and programmed cell death. As such, organisms have multiple complex pathways dedicated to repairing DSBs. These repair pathways begin with a signaling cascade that results in the resecting of the ends of the break to create 3’ OH overhangs which are immediately bound by a single-stranded binding protein called Replication Protein A (RPA). This is followed by the cell either undergoing programmed cell death or utilizing non-homologous end …

Streamer Dynamics In Thunderstorm And Near-Ionospheric Environments, Jacob Koile

Doctoral Dissertations

Streamers are self-consistent ionization waves that are generated within an electric field. Since they were first proposed in the theory of spark breakdown developed in the 1930s by Raether, Loeb, and Meek [Raether, 1939; Loeb and Meek, 1940], they have demanded the attention of scientists across many different fields. They are crucial to the Earth environment because of their natural occurrence in the form of sprites, at near-ionosphere altitudes above a thunderstorm, and their proposed roles in the formation and propagation of lightning. % that can occur above a thunderstorm, or However, they also play a role in the human …

Asymptotic Spectral Analysis Of A Coupled Bending-Torsion Beam Energy Harvester, Chris Vales

Doctoral Dissertations

A piezoelectric energy harvester is a device that utilizes the properties of piezoelectric materials to convert mechanical strain energy into electric energy. The present work is concerned with the asymptotic spectral analysis of a piezoelectric harvester extracting energy from the mechanical vibration of a coupled bending-torsion beam. After placing the model in the appropriate operator setting, we prove that the addition of piezoelectric energy harvesting constitutes a weak perturbation of the underlying beam dynamics, in the sense that the model’s piezoelectric parameters do not appear in the first two orders of magnitude of the asymptotic approximation of the governing operator’s …

Plasma Membrane Remodeling And Biochemical Mechanisms Underpinning Bacterial Persistence In Fractured Subsurface Shale, Chika Jude Ugwuodo

Doctoral Dissertations

During hydraulic fracturing, a water-based fluid containing proppants and several chemical additives is injected under high pressure into a ~2 km deep wellbore, to extend fractures in the underlying rock. This process introduces a host of microorganisms into the reservoir, some of which survive, persist for long periods of time and cause several problems including production of H2S, a corrosive toxicant and biofilm formation which clogs rock fractures. Over time, the bacterial genus Halanaerobium dominates the microbial community composition in many geologically distinct fractured formations. Our understanding of shale reservoir microbial dynamics remains limited despite extensive studies in the past …

Shattering Ceilings: Women Of Color, Mentorship, And Corporate Oppression, Raminder Kaur Attwal

Doctoral Dissertations

In the Fortune 500 organizations, a robust survey illuminates the diverse experiences of women of color, framed within theoretical frameworks such as Critical Feminist Theory (CFT), Social Capital Theory, and Community Cultural Wealth. Of 141 responses, 102 participants, representing various racial backgrounds, provide insights into corporate landscapes. Their positions range from mid-level to executive roles, showcasing a holistic view of organizational hierarchies. Remarkably, approximately 70.59% engage in formal mentorship programs, highlighting its profound impact on career development.

Assessing the effectiveness of tailored mentorship initiatives, the research emphasizes their transformative power in confronting oppressive corporate norms, drawing from insights provided by …

The Aspirations Of The Youth Of South Sudan Towards Tertiary Technical Education, Peace, Development And Civic Engagements, Sunil Orathel

Doctoral Dissertations

South Sudan, the youngest nation in the world, gained independence on July 9, 2011, following many long years of civil war and untold human suffering. After a decade of independence and millions spent from international assistance, neither stability nor development have been secured in the country. Although primary education is improving, tertiary education, particularly tertiary technical education, is considered a neglected sector. This descriptive mixed-method study documents and analyzes 1,461 surveys and 60 interviews, capturing the aspirations of the secondary school youth and stakeholders across the nation of South Sudan towards tertiary technical education, peace, development and civic engagements. Historical …

The Impact Of Institutional Support On African American Male College Students: A Phenomenological Analysis, Samuel Leron Speed

Doctoral Dissertations

This study is a powerful call to action for higher education institutions to recognize and address the unique challenges of African American male college students. Through a qualitative phenomenological approach grounded in Swail's (2004) Framework for Student Success, the study sheds light on the institutional factors that impact the lives of these students. The research design utilized semi-structured interviews with seven African American male participants, and the analysis reveals codes, clusters, and themes that emerged from their narratives, providing valuable insights into the impact of institutional support on their lives. The study highlights the importance of peer support, the challenges …

Blow-Spun Hybrid Pcl-Peo/Hnts Scaffolds With Enhanced Biological And Mechanical Properties, Meichen Liu

Doctoral Dissertations

With the development of technology and engineering, nanotechnology has been a multidisciplinary scientific field applied in nearly all science areas, including medicine, genetics, food industry, robotics. In this respect, nanomedicine has gained increasing attention and been a useful, effective therapy for cancer diagnosis, gene transfer, and drug delivery. To design an ideal nano drug delivery system with controlled drug releasing and improved encapsulated drug’s pharmacokinetic and pharmacodynamic profiles, hydrogels and polymer composites have witnessed increased research interest during the last decades. Recently, numerous polymers have been studied to fabricate the ideal wound dressing with biocompatibility, biodegradability, porous structural, and suitable …

Development Of An Integrated Workflow For Nucleosome Modeling And Simulations, Ran Sun

Doctoral Dissertations

Nucleosomes are the building blocks of eukaryotic genomes and thus fundamental to to all genetic processes. Any protein or drug that binds DNA must either cooperate or compete with nucleosomes. Given that a nucleosome contains 147 base pairs of DNA, there are approximately 4^147 or 10^88 possible sequences for a single nucleosome. Exhaustive studies are not possible. However, genome wide association studies can identify individual nucleosomes of interest to a specific mechanism, and today's supercomputers enable comparative simulation studies of 10s to 100s of nucleosomes. The goal of this thesis is to develop and present and end-to-end workflow that serves …

Selective Targeting Of Microglia By Quantum Dots And Green Synthesis Of Metal Organic Biohybrids; Applications In Dynamic Cell And Assay Systems, Navya Uppu

Doctoral Dissertations

Neurological disorders are the leading cause of physical and cognitive disability across the globe, currently affecting approximately 15% of the worldwide population. Part of the glioma microenvironment are microglia, resident immune cells of the CNS that were thought to be involved in the pathogenesis of diverse neurodegenerative diseases. Though it remains uncertain what triggers microglial activation in these disorders, targeting and tracking microglial functions using nanotools like Quantum Dots (QDs) could help us elucidate them in such neurological diseases. This research focuses on the comparative study of different QDs formulations and their selective uptake by brain microglia in primary cultures …

Development And Characterization Of Injectable, Cell-Encapsulated Chitosan-Genipin Hydrogels, Tyler R. Priddy-Arrington

Doctoral Dissertations

Over 150,000 patients undergo lower extremity amputation every year in the United States, most commonly caused by complications due to diabetes mellitus, peripheral vascular disease, and trauma. Diseased or damaged tissues that are unable to naturally repair themselves must either be fully removed or replaced, otherwise the injuries can lead to further complications such as infection or death. Tissue resection and amputation, as forms of removing damaged tissue, are not favorable to patients as they can cause pain, reduce mobility, and negatively impact quality of life. However, replacing lost or damaged tissues with donor tissues carries the risks of tissue …

In Situ High Temperature Fiber-Optic Raman Sensor For Industrial Applications, Bohong Zhang

Doctoral Dissertations

"Continuous casting in steel production uses specially developed oxyfluoride glasses (mold fluxes) to lubricate a mold and control the solidification of the steel in the mold. The composition of the flux impacts properties, including basicity, viscosity, and crystallization rate, all of which affect the stability of the casting process and the quality of the solidified steel. However, mold fluxes interact with steel during the casting process, resulting in flux chemistry changes that must be considered in the flux design. Currently, the chemical composition of mold flux must be determined by extracting flux samples from the mold during casting and then …

Re-Evaluating Missouri’S Strategic Element Potential: A Geochemical Study Of The Mesoproterozoic Fe-Cu-Co-Ree Deposits In Southeast Missouri, Usa, Brandon James Sullivan

Doctoral Dissertations

"Iron-oxide-copper-gold (IOCG) deposits are poorly understood mineral systems. For example, we do not know why Cu- and Co-rich IOCG deposits typically occur proximal to Fe ore deposits that are notably Cu and Co-poor, such as Iron Oxide Apatite (IOA) deposits. To better understand the formation of IOA and IOCG deposits in Missouri, USA, this PhD thesis examines the genesis of the Kratz Spring IOA and the Boss Central Dome IOCG deposits. This study presents the first constraints on formation conditions and fluid sources in the studied deposits using integrated petrographic, mineral composition, and Fe isotope analyses of oxide minerals. Observations …

Investigation Of Asphaltene Instability Under Gas Injection In Unconventional Reservoirs And Its Impact On Oil Recovery Performance, Mukhtar Elturki

Doctoral Dissertations

"Unconventional reservoirs, such as shale gas and tight oil formations, have become an important source of energy in recent years. However, these reservoirs often contain high levels of asphaltenes, which can lead to deposition and blockages in production wells and reduce the flow of hydrocarbons during gas enhanced oil recovery (GEOR) techniques. This study aims to experimentally evaluate the impact of miscible and immiscible carbon dioxide (CO₂) and nitrogen (N₂) on asphaltene deposition and its impact on oil recovery performance in unconventional shale reservoirs.

This research began with a comprehensive literature review and data analysis of GEOR methods in unconventional …

Design, Synthesis, And Characterization Of Complex Chalcogenides For Energy Storage And Energy Conversion Applications, Srikanth Balijapelly

Doctoral Dissertations

"Through this investigation, complex chalcogenides with the combination of main group metals, transition metals, and rare earth metals have been synthesized using the building block approach and their structure-property relationships are evaluated. The main emphasis of research is on rationally designing new materials for applications in sodium and lithium ion conducting solid electrolytes, cathodes, thermoelectrics, and nonlinear optics. Along with the experimental studies, theoretical calculations are also employed to better understand the physicochemical properties of the synthesized compounds.

The first part of the research will discuss designing alkali ion containing complex chalcogenides using the building block approach. This investigation resulted …

Non-Linearity Modeling And Quantifications For Practical Rf Interference Control, Shengxuan Xia

Doctoral Dissertations

"Radio frequency (RF) interference can degrade the receiving sensitivity of antennas (desense problem). It is essential to model the nonlinearity as it is the root-cause of the unwanted frequency components. Understanding the electromagnetic (EM) coupling or radiated emissions is also important.

Nonlinearity causes modulation-involved desense problems, and it consists of two categories: upconvertion of the baseband noise by the transmitting (TX) signal, and the passive intermodulation (PIM) of the transmitting signal itself. The upconvertion caused desense can be modeled and analyzed with the dipole-moment based coupling framework. PIM has been identified as another nonlinear distortion mechanism, specifically in the metallic …

Accurate And Time Efficient Signal Integrity And Power Integrity Modeling Of High-Speed Digital Systems, Chaofeng Li

Doctoral Dissertations

"Signal integrity (SI) and power integrity (PI) play an important role in the modern high-speed digital system design, which are closely related to the printed circuit board (PCB) dielectric material property, the PCB interconnect performance, and the power delivery network (PDN) on PCB. Generally, the full-wave simulation is used to accurately analyze and evaluate the designed PCB. But full-wave simulation is not a good option for the complex PCB structure with high aspect ratio, for example, PCB vias, and PDN, which will require significant computing time and storage resources. Equivalent circuit models have been developed to efficiently predict the electrical …

In Situ Infrared Thermographic Inspection In Additive Manufacturing, Tao Liu

Doctoral Dissertations

"Laser Powder Bed Fusion (LPBF) is a key technique in metal additive manufacturing and has undergone extensive research over the past few decades. It enables the fabrication of complex geometries directly from digital design models. The solidification process in LPBF is heavily influenced by the characteristics of the powder layer, including its thickness and thermal transport properties. Additionally, the performance of the printed part is impacted by the temperature history during solidification and the final residual stress field. While these topics have been the focus of many studies, almost all research has concentrated on ex-situ measurement and testing. These ex-situ …

Topography Of The 410 And 660 Km Discontinuities Beneath The Tibetan Plateau And Adjacent Areas, Zexin Miao

Doctoral Dissertations

"The Tibetan Plateau represents the ongoing geotectonic aftermath of a continental collision initiated approximately 65 million years ago. Despite numerous seismological studies, controversies remain regarding the structure, evolution, and dynamics of the crust and mantle beneath Tibetan Plateau. In this study, we used teleseismic broadband data to investigate the topography of the mantle transition zone (MTZ) discontinuities. A total of ~655,000 receiver functions from 735 stations was utilized to image the 410 and 660 km discontinuities bordering the MTZ. Combining the observed and velocity corrected results, several areas in the central Tibet exhibit a typical d410 and an anomalously deep …

Enabling Improved Hand Function In Disabled Individuals Via Intention Estimation And Suppression Of Disrupted Central Drive, Hendrik Adriaan Dewald

Doctoral Dissertations

No abstract provided.

Uas-Based Detection And Quantification Of Pavement Roughness And Vertical Deviations Due To Frost Heave, Farah Zaremotekhases

Doctoral Dissertations

This research leverages Unpiloted Aerial Systems (UAS) equipped with advanced sensing technologies—optical imaging and Light Detection and Ranging (LiDAR)—to accurately detect and measure pavement frost heaves, which cause significant structural damage and surface roughness, particularly in cold climate regions. The use of UAS platforms is driven by the need to provide measurements over large areas and to offer high-precision, accessible, and efficient data collection methods capable of operating in challenging and difficult-to-access regions. Furthermore, UAS technology enhances safety and saves time and labor, enabling quicker, and safer assessments with minimal disruption. Experiments were conducted on both simulated and actual pavements …

A Mean-Field Modeling Framework Incorporating Intragranular Orientation Spreads To Improve Modeling Of Deformation Twinning, Recrystallization And Geometrically Necessary Dislocations, Iftekhar Alam Riyad

Doctoral Dissertations

Metallic components go through a complex sequence of deformation processes during manufacturing. The purpose of a structural component dictates the use of specific metallic material with a given set of mechanical properties. In order to predict material behavior and microstructural evolution during deformation on a computer rather than in a workshop, computationally efficient models have been developed over the past several decades. Mean-field plasticity models like viscoplastic self-consistent (VPSC) and elastoplastic self-consistent (EVPSC) models are popular for their efficiency in terms of computational time compared to full-field models but lack in accuracy due to the consideration of only mean field …

Observing And Estimating Soil Freeze Thaw Processes: From Remote Sensing To Land Surface Modeling, Mahsa Moradikhaneghahi

Doctoral Dissertations

Freezing conditions affect more than half of the exposed land in the Northern Hemisphere in cold seasons, where transitions between frozen and thawed states impact surface and subsurface water and energy budget. Recognized as an Essential Climate Variable (ECV), accurate, reliable and efficient estimates of soil freeze/thaw (FT) processes with a moderate spatiotemporal resolution are needed to fully resolve highly-dynamic processes taking place at the land-atmosphere interface. Active microwave remote sensing and land surface modeling are promising tools for advancing the monitoring of FT as an ECV. My dissertation addresses key scientific gaps in estimating soil FT conditions using active …

Natural Laboratories Of The Deep Sea: Linking Community Composition And Environmental Variables On Low-Temperature Venting Outcrops Of Ridge Flank Hydrothermal Systems To Explore Potential Impacts Of Climate Change, Inform Habitat Suitability Models, And To Understand The Impacts Of High Bathymetric Resolution On Seafloor Characterization, Anne Marie Hartwell

Doctoral Dissertations

The deep sea covers over two-thirds of the globe and represents 95% of the ocean. Most life on Earth is suspected to live on or near the seabed. Yet, these ecosystems are the least known on Earth and are important to explore as they are home to a diverse array of species that are currently under threat because of multiple anthropogenic pressures, including warming oceans. Exploration of these systems is critical to further the understanding of species interactions, biodiversity and their overall relationship to environmental and terrain variables. Many of these variables are used in species distribution models and technological …