Digital Commons Network^™

Emulation Of Orbital Dynamics And Control Of Fully Actuated Seven-Axis Prismatic Joint Systems, Bennett Russell

Electrical and Computer Engineering ETDs

This thesis details the system modeling, design, control, simulation, construction, and testing of a fully-actuated seven axis prismatic joint system created for the primary purpose of emulating on-orbit maintenance tasks. Additionally, it seeks to further research of space-based control schemas and investigate stiction as a case study with a mountable hybrid hinge system that emulates stiction. Controllers are evaluated under common limits and metrics, including time to escape, overshoot, mechanical work, and limit-exceedance counts. Comparisons span a PID baseline, deterministic MPC/MPPI, and a probabilistic POMDP policy. Results verify the emulator and hybrid hinge meet the intended design criteria and show …

Listen To The Birds: Sound Ecology At The Piano, Anna Showalter

Dissertations, 2020-current

This document explores the intersection between birdsong and piano music using four cases studies from the piano repertoire in the Western classical tradition. Using Jeff Titon’s framework of “sound ecology” as a lens, I ask whether the following pieces of music could in some way function as an “acoustic tissue among human and bird communities that becomes the basis for a healthy economy and a just community.” After exploring the history of birdsong in the piano literature as a microcosm of shifting attitudes toward birdsong in Western art music this study focuses on four pieces as case studies for analysis—Amy …

Corporeality In Choral Sound: Elements Of Consonant Diction Shaping Pre-Expressive Presence, Perceived Clarity, And Expression In English-Language Choral Music, Addison Walton

Dissertations, 2020-current

The genesis of this project stems from a lived experience performing with a professional choir, whose sung physical shaping of the English language—its crystalline clarity, profound expressivity, and the pre-expressive elements inherent in the delivery—was deeply and viscerally compelling. This overwhelming reaction was in response to their bodies; specifically, the sound their bodies produced that evoked a sense of corporeality, or tangible bodily presence. There was beauty to be found in the way their mouths physically formed the language, both within and removed from the semantic context.

This study sought to acknowledge those fleeting, pre-expressive moments in choral music and …

Log Cabins, Hard Ciders, And The Misunderstood Campaign Of 1840: Looking At How The Whigs Really Created The First Modern Presidential Campaign Through Effective Storytelling, Eric V. Schesventer

Masters Theses, 2020-current

The Whig party crafted the first ever modern campaign seen in American History during the campaign and subsequent presidential election of 1840. They did this not merely through the use of flashy campaign slogans and festive events as previous historians have discussed. The Whigs created the first ever modern campaign by telling both realistic and symbolic stories through the use of media narratives and physical objects crafted for the campaign. By doing this, this helped mold then candidate and future President William Henry Harrison into a candidate for all Americans, even if he was not in practice.

Knowledge Production As Identity Expression: A Third-Space Perspective On Sustainable Careers, Alicja Syska

School of Law, Humanities and Social Sciences

This conceptual paper advances our understanding of sustainable careers by focusing on the knowledge creation activities of third-space practitioners in higher education. Specifically, we apply and extend the Process Model of Sustainable Careers to examine how different forms of knowledge production in three different institutional and national contexts – writing for publication, practice-based expertise, and curriculum development – contribute to career sustainability at the intersection of academic and professional/administrative roles and domains. The critical element of this extension is ‘identity expression’ in the form of knowledge production, which acts as an integrating mechanism that flows through and connects the original …

Investigating The Fatigue Behavior Of Inconel 939 And Inconel 718 Through Micromechanical Testing, Mohammad Hossein Shahini

LSU Doctoral Dissertations

A detailed evaluation of fatigue crack growth (FCG) in a silicon-modified Inconel 939 alloy, fabricated via laser powder bed fusion additive manufacturing (L-PBF AM), was performed using cyclic bending tests on pre-notched microscale cantilevers with a cross-sectional dimension of 25 µm × 25 µm. To our knowledge, this study is the first to demonstrate that such microscale cantilever tests can effectively capture both the threshold and Paris-law regimes of FCG, despite the limited specimen size. The precise fabrication of these small-scale specimens allows for controlled fatigue crack propagation relative to the microstructure while minimizing the presence of volumetric defects. Notably, …

Diplomacy Derailed: Discrimination’S Detour On Route 40, Gage A. Kivlen

Masters Theses, 2020-current

The 1961 Route 40 campaign in Maryland became a critical battleground where three competing approaches to addressing racial segregation revealed deep contradictions in Cold War America. Route 40, a major highway between Washington D.C. and New York, became an international embarrassment when African diplomats from newly independent nations were repeatedly refused service at restaurants and hotels. This crisis prompted responses from three distinct actors: the Congress of Racial Equality (CORE), which employed grassroots organizing and direct action; the State Department's Special Protocol Service Section (SPSS), which pursued top-down diplomatic solutions; and the Federal Bureau of Investigation (FBI), which conducted extensive …

Recreating Fiber Recruitment With Fiber Recruitment Using Additive Manufacturing, Natalia D. Mciver

Biomedical Engineering ETDs

Injured ligaments are often repaired with tendon grafts which may over or under constrain the joint; there is a need for an artificial graft option with the mechanical properties of a native ligament. Crimped fibers within ligaments allow for recruitment which means the viscoelastic properties of stress relaxation and creep are not inversely related. A feasibility study using ACLs and large-scale crimp models to study viscoelasticity, led to an in-depth analysis of the scapholunate interosseous ligament. Using the Modified Kelvin spring-dashpot model, for describing viscoelasticity with a variable stiffness property (time dependent fiber recruitment), we defined the relationship between creep …

San Mateo County’S Digital Jail Mail Sparks Reckoning Over Private Data, Juan A. Lasso

Capstones

This capstone examines privacy and data risks embedded in digital communication systems used in U.S. correctional facilities. As private vendors introduce tablets, kiosks, and mail digitization services, these technologies enable widespread surveillance and data collection of incarcerated people and their loved ones. The project explores how these systems track and analyze digital footprints in ways that challenge established legal and ethical expectations around privacy. It documents the personal impact on loved ones of people currently or formerly incarcerated in San Mateo County. The reporting centers on the California county jail where a civil rights lawsuit is pending over the mail …

Halt Under Threat Why Legislators Must Demand Compliance Before Change A Playbook For Action, Vanda Seward

Capstones

This playbook examines the implementation of New York State’s Humane Alternatives to Long-Term Solitary Confinement (HALT) Act and presents evidence demonstrating that the law has not been fully or consistently enforced by the New York State Department of Corrections and Community Supervision (NYSDOCCS). Drawing on findings from the New York State Inspector General, the Correctional Association of New York, the Justice Center, court rulings, and community testimony, the analysis documents persistent violations, including excessive and illegal use of solitary confinement, inadequate documentation, failures to protect vulnerable populations, and insufficient accountability for staff misconduct. The playbook critically evaluates the recommendations of …

Defiance Through Noise, Tyler Paz

Capstones

Defiance Through Noise analyzes the eviction of Punk HQ from 39 Eldridge Street within the broader history of punk-led, DIY, and squatted spaces in New York City. Using court records, historical context, and firsthand accounts from organizers, former nonprofit workers, and participants, the project examines Punk HQ as both a community space for marginalized youth and a continuation of Lower East Side squatting traditions from the 1970s and 1980s. The reporting situates its closure within intersecting forces of government disinvestment, housing policy, post-pandemic economic pressures, and the nonprofit industrial complex that have contributed to the decline of autonomous cultural spaces. …

Building Another World, Christopher Edwards

Capstones

"Another World" is a mutual aid hub in Crown Heights, Brooklyn. The space was opened in June 2025 and is ran by the Crown Heights Care Collective, a mutual aid network started in 2022. Another World hosts free events surrounding political education and provides basic needs like food and clothing to residents of the area. In just a few months, the group has made inroads in a diverse community altered by gentrification.

Fedchae: Federated Learning With Client Clustering And Hybrid Adaptive Engagement, Chaeeun Park

Electrical and Computer Engineering ETDs

As machine learning adoption expands, data privacy concerns have grown significantly. Federated Learning (FL) addresses this challenge by allowing clients to train locally and share only their model parameters with the server. However, conventional FL methods such as FedAvg suffer from high communication overhead, as all clients must participate in every global round.

This paper proposes FedChae (Federated Learning with Client Clustering and Hybrid Adaptive Engagement) to balance communication efficiency and model accuracy. FedChae alternates between Grouping Rounds, where all clients perform clustering, and Conventional Rounds, where one client per cluster updates the model.

Simulations with 100 clients using Multi-class …

Empowering Wireless Mesh Uav Networks Through Software-Defined Networking, Hieu Quang

Electrical and Computer Engineering ETDs

Unmanned Aerial Vehicles (UAVs) have been widely deployed in applications such as environmental monitoring, disaster response, and surveillance. Effective coordination between UAVs depends on low-latency inter-UAV communication to exchange state information, decisions, and other critical data. UAV networks are inherently dynamic which necessitates a framework capable of handling scenarios such as traffic re-routing, and resilience to communication failures. To address the challenges of managing dynamic UAV networks, this thesis proposes a dual network approach composed of three main components. First, the Better Approach to Mobile Ad-hoc Networking (BATMAN) protocol is used to enable communication among UAVs. Second, the OpenFlow protocol …

2025 Fall Commencement, Harding University

Commencement Programs

Program for the Harding University Commencement on December 13. 
Commencement Speaker: Dr. Susan Kehl

Efficacy Of Oil And Gas Production Site Remediation In U.S. Arid/Semi-Arid Regions, Skye Ontiveros

Architecture and Planning ETDs

Oil and gas production (OGP) is expanding, paralleled by its polluting leaks and spills (LS), and outpaced by its waste. This raises the question: Does remediation of LS occur effectively when needed to protect the environment and public, particularly in major producing regions like arid/semi-arid regions (ASAR), which account for approximately 72% of US oil and 42% of gas production? To answer, a review of the eight largest national remedial laws, sourced from the Code of Federal Regulations (CFR), identified 14 OGP exemptions for remedial determinants (RDs): factors affecting remedial frequency and efficacy (e.g. LS monitoring and chemical disclosure). An …

Design And Evaluation Of The Influence Of Mutual Induction On Microbial Electrolysis Cell Performance And Biogas Production, Ashley L. Blackwell

Civil Engineering ETDs

Microbial electrolysis cells (MECs) present a pathway for energy recovery in wastewater treatment by converting organic substrates into methane or hydrogen. Traditional MEC designs typically rely on physical electrode contacts and expensive materials, which restrict their scalability. This study introduces the first induction-based MEC that uses mutual inductance between an external copper wrap and an internal coil to generate a fluctuating electrical potential, removing the need for expensive electrodes. The induction-stimulated reactor showed faster total organic carbon removal and a higher CH4/CO2 ratio compared to a conventional anaerobic digester, indicating improved carbon-to-methane conversion, although total gas yield remained similar. Microbial …

How To Talk To A Seahorse: Communication In Transmasculine Gestational Experiences As Told Through Narrative, Emerson Armstrong

Communication ETDs

Transmasculine experiences before, during, and after pregnancy were evaluated using focus groups and autoethnographic research. As transgender people are more likely to experience inequality in healthcare encounters, this project aims to shed light on, and counter sensationalized accounts of male pregnancy, as transmasculine gestational individuals sought normalization in their experiences of pregnancy. Seven focus groups consisted of 90 minute sessions, with a total of 15 participants. Transcripts were analyzed using a trans narrative approach to find a greater understanding about identity construction, challenges, and changes around trans pregnancy. Asking about communities and healthcare experiences worked to create a complete picture …

Graph Based Planning With Guarantees, Trazon Tyrik Jimerson

Mechanical Engineering ETDs

This thesis presents two graph-based methods with formal guarantees for motion planning and routing. First, the invariant-set motion planner (ISMP), which uses constraint admissible positive invariant (CAPI) sets of closed-loop dynamics, is adapted for spacecraft attitude planning to avoid moving keep-out zones. Contributions include time bounds for maneuvers via exponential stability, a single-stage reachability graph from one-step backward reachable CAPI sets, and its multi-stage expansion to certify node safety over time. Simulations verify safe attitude control with moving obstacles. Second, we formulate a convex optimization problem over a network for evacuation planning with operational constraints such as helicopter capacity and …

Simulation Of Stress Induced By Laser Heating Of Glass, Austin Marsh Schuberth

Mechanical Engineering ETDs

The purpose of this work is to create a method for accurately simulating the stresses due to heating from femtosecond laser pulses. Our work aims to calculate stress and strain in glass exposed to laser pulses used for laser welding. We simulate the effects of thermal heating, thermal expansion, and the viscoelasticity of glass for a single straight weld bead. The laser heating of K9 borosilicate glass was simulated using Finite Element Analysis (FEA). Thermal models developed by other researchers in earlier work were utilized in calculating the temperatures due to the laser exposure to the glass material. 2D simulations …

Real-Time Frequency Tuning Of Kinetic Energy Harvesters Via System Mass Adjustment, Rahul Adhikari

Mechanical Engineering ETDs

This research presents a method for real-time frequency tuning of piezoelectric kinetic energy harvesters through system-mass adjustment. Custom 3D-printed proof masses with cavity arrays were used to redistribute solid or liquid mass, enabling controlled modification of resonant frequency. Experimental studies using microparticles and liquids—including water, silicone oil, and sodium polytungstate—demonstrated an achievable tuning range of 115.27 Hz with sub-hertz resolution (< 0.1 Hz), confirming precise and repeatable frequency control. Finite-element modeling guided design optimization, while a microfluidic channel system enabled automated liquid filling for real-time operation. A MATLAB-based EH_Tuning application was developed to visualize and predict frequency responses. The combined …

Design And Development Of Evacuated Photovoltaic-Thermal Systems For Efficient Cogeneration Of Heat And Electricity, Behnam Roshanzadeh

Mechanical Engineering ETDs

In conventional PV systems, most of the solar energy is dissipated into the environment as heat. Accordingly, hybrid Photovoltaic-thermal systems have been developed to utilize the waste heat from PV cells for various thermal applications. However, most PVT systems suffer from low thermal performance compared to solar thermal collectors, as the absorber plate in PVT systems is partially or fully covered by PV cells. This dissertation focuses on improving the thermal performance of PVT systems by introducing the evacuated PVT systems.

An evacuated-tube PVT system was designed and simulated for domestic hot water supply. The evacuated-tube PVT system demonstrated 40% …

Dense Temporary Array Investigation Of Jemez Uplift Seismicity, Jillian D. Podmore

Earth and Planetary Sciences ETDs

A protracted multi-stage tectonic and magmatic evolution combined with low regional crustal strain rates make it challenging to characterize active structure that may host earthquakes in the Jemez Mountains of New Mexico. Here, we leverage temporary 1-month deployments of nodal seismometers to gain new insights into seismicity of the Jemez Mountains, which only have continuous seismic monitoring on their eastern flank as a result of the Los Alamos Seismic Network. Our catalog is built using 4 steps: phase picking in continuous seismic data, association of picks to detect unique events, event magnitude estimation, and absolute hypocenter estimation. We detect and …

Seismological Investigations Of Magmatic Systems Using Dense Nodal Arrays, Wenkai Song

Earth and Planetary Sciences ETDs

Understanding the internal architecture of magmatic systems is crucial for volcanology, yet conventional geophysical techniques often lack the resolution to image their fine-scale structures. This dissertation leverages unique datasets from dense nodal arrays to investigate the upper crustal magmatic systems beneath Yellowstone Caldera, Valles Caldera, and Mount St. Helens. At Yellowstone, I processed vibroseis data to delineate the top of the modern magma reservoir and evaluate the thermal connection between the magmatic and the overlying hydrothermal systems. At Valles, 3D radial seismic anisotropy imaging reveals strong positive radial anisotropy within the reservoir, indicating an organized structure of horizontally sill-like melt …

Application Of Bimetallic Transition Metal Oxides Electrocatalysts For Li-Co2 Batteries And Li-O2 Batteries, Jianda Wang

Chemical and Biological Engineering ETDs

Li-ion batteries are the dominant commercial rechargeable batteries nowadays, which are used in electronic devices and electrified transportation widely. However, undesirable energy density of Li-ion batteries prohibits them from meeting requirements of new generation electronic devices. Therefore, it is important to find more alternative electronic energy storage systems with higher capacity. Fortunately, Li-CO2 batteries, featured high capacity and ability to convert CO2, have become a promising candidate to replace Li-ion batteries. In addition, Li-O2 batteries also attract people’s attention due to their high energy density and low cost. However, Li-CO2 batteries and Li-O2 batteries both face challenges of terrible cycle …

Physical Education Through The Lens Of A Transgender Individual, Allison L. Graham

Health, Exercise, and Sports Sciences ETDs

Transgender students face unique challenges in K–12 physical education (PE) that other groups of students do not experience. The purpose of this qualitative study was to explore the life history of a transgender woman, Evergreen, with a focus on her experiences in PE throughout K-12 school. This study was guided by Queer Theory (Jagose, 1996) and Atkinson’s (1998) life history methodology, data was collected through nine semi-structured interviews and participant-selected artifacts. Data was analyzed using Merriam and Tisdell’s (2016) coding procedures to identify themes. Findings revealed distinct experiences across four areas: (1) Elementary School PE—positive memories centered on play …

Predicting The Unpredictable: Advancing Risk Management In Fitness Centers Through Data Science-Driven Judicial Outcome Modeling, Hongyoung Kim

Health, Exercise, and Sports Sciences ETDs

This study developed a prediction model of judicial outcomes in fitness exercise-related injury lawsuits to identify key factors influencing fitness centers’ success in litigation. Using 209 U.S. court cases from Westlaw, Phase One employed text mining and content analysis to identify legal variables. Phase Two applied descriptive statistics and multiple logistic regression to evaluate the combined influence of these variables on judicial outcomes. For the multiple logistic regression analysis, the sample size was reduced to 184 cases after excluding 25 remanded cases.

Results showed that victim behavior, hazardous facility conditions, and enforceable waivers or exculpatory clause defenses significantly predicted judicial …

Analysis Of Heat Transfer And Pressure Drops Associated With Twisted Tube Heat Exchangers, Braden Foderaro

Nuclear Engineering ETDs

Several studies have been done on the effects of twisted tubes in heat exchangers, including the correlations that relate the flow parameters to the heat transfer and pressure drop experienced. These studies are new, with the earliest being performed in 1982. As such, there are many correlations covering only certain flow parameters and geometrical configurations such as the Reynolds number and modified Froude number.

This thesis attempts to cover flow regimes and tube geometries not yet studied and yield correlations. Data are gathered from heat exchangers featuring twisted tubes with water as the working fluid. It is noticed that the …

Non-Destructive Characterization Of Ion Irradiated Yttrium Hydride For Microreactor Applications, Ryan E. Pena

Nuclear Engineering ETDs

As energy demands increase, nuclear reactors, especially microreactors, become a promising energy source. These reactors run at high temperatures (>280°C), requiring moderators that can endure these environments. Yttrium hydride is a possible moderator, but little is known about the material’s phase stability and hydrogen retention under irradiation. Through the use of a gold ion beam, samples with stoichiometries ranging from 1.6 to 2.0 were irradiated and tested. Through Vickers hardness testing, a model was created showing a correlation between hydrogen content and hardness. Raman spectroscopy showed high temperature and irradiated samples have significant hydrogen loss. XRD quantified this hydrogen …

Sequential Low Dose Proton Irradiation And Nanomechanical Testing To Understand Mechanical And Microstructural Property Changes In Alloy 709, Abhishek Kc

Nuclear Engineering ETDs

Alloy 709, a 20Cr25Ni alloy, is an advanced austenitic steel designed for next generation sodium fast reactors. Preliminary studies have shown the potential of Alloy 709 in sodium fast reactors. In this study, Precipitate Treated Alloy 709 specimens are irradiated with 2 MeV H⁺ at 500 °C from 0.0057 dpa to 1.7 dpa. Electron microscopy characterization techniques are used to understand the effects of radiation on mechanical properties as well as microstructure of Alloy 709. The microstructure did not show formation of voids, amorphization of precipitates, or increase in grain size up to 1.7 dpa. Correspondingly nano-indentation and micro-pillar …