Digital Commons Network^™

Mechanical Behavior Of Additively Manufactured Ti-6al-4v Eli Parts: Effects Of Laser Parameter Selection, Samuel Lopez

UNF Graduate Theses and Dissertations

Additive manufacturing (AM) of TI-6AL‑4V Extra‑Low Interstitial (ELI) enables complex geometries for fatigue‑critical medical device applications, yet fatigue performance remains sensitive to process‑induced defects. This work investigates the effect of laser process parameter selection on the microstructure, mechanical properties, and fatigue behavior of TI- 6AL‑4V ELI fabricated via laser powder bed fusion (L‑PBF) using a Renishaw RenAM system. The influence of laser parameters was isolated by holding powder chemistry, build orientation, scan strategy, sub‑transus annealing, and post‑processing constant between a non‑optimized baseline and an optimized parameter set selected based on tensile performance.

Optical microscopy showed the optimized condition exhibited improved …

For Whom The Tale’S Told: Multilevel Perspective On Narrative And Identity In Information Ecosystems, Jihye Song

Graduate Studies Theses and Dissertations 2026

In contemporary online information environments, narratives do not merely convey facts. They organize meaning, signal identity, and guide collective sensemaking. During periods of crisis and uncertainty, these processes become especially salient, as individuals and communities turn to social media to interpret unfolding events. At the same time, these environments are shaped by complex sociotechnical dynamics, including platform affordances, algorithmic amplification, elite influence, and grassroots participation. These dynamics form ecosystems in which narratives and identities are constructed, contested, and stabilized. Drawing on theory and empirical analyses of COVID-19 discourse on Twitter, this work develops and applies a multilevel framework to explain …

Forest Island Reforestation In The Llanos De Moxos, Bolivia, Ethan Tam

Graduate Studies Theses and Dissertations 2026

Within the Llanos de Moxos of Bolivia thousands of forest islands dot the landscape. These forest islands have been shown to have been integral aspects of the pre-Contact indigenous cultures which existed there for thousands of years. Based on 1967 CORONA imagery and statistical analysis, this work provides insight into how these forest islands are integrated as infrastructure features within their landscape and surrounding network of other archaeological features. This research is carried out through investigations into changes in the size of the forest islands across an interval of 57 years, statistical attempts to categorize the forest island into smaller …

Threads Of The Past: Exploration Of Banal Medievalisms In Russia's Invasion Of Ukraine, Evan Garrett Wallace

Graduate Studies Theses and Dissertations 2026

This dissertation examines how medieval historical narratives circulate within contemporary Western digital discourse surrounding Russia’s invasion of Ukraine. Russian political rhetoric has frequently invoked the medieval polity of Kyivan Rus’ to assert civilizational continuity between the medieval past and the modern Russian state. While these claims have been widely discussed in political and media contexts, less attention has been given to how such narratives appear within everyday online discourse. This study investigates how medieval references are mobilized, circulated, and interpreted within social media environments during the early conflict.

The research draws on a dataset of approximately 160,000 tweets collected from …

Dynamic Interactions Of The Compressible Reacting Flow With A Morphing Wall In A Supersonic Combustor, Mason R. Thornton

Graduate Studies Theses and Dissertations 2026

The influence of compressibility on supersonic reacting flows is explored by varying the area expansion ratio in a supersonic cavity combustor using a moving wall. In principle, this design allows on-the-fly adjustment of the combustor aft wall expansion ratio to accommodate variable inlet conditions and fueling rates. The variable back pressure broadens the operability envelope and ensures greater pressure rise recovery compared with a constant geometry combustor. The results demonstrate that modulating area expansion alters the combustor pressure distribution and can influence cavity flame dynamics. At sufficiently high equivalence ratios and compression levels, the back pressure induced by the moving …

A Sensor Fusion And Optimization Framework For High-Resolution Power Outage Detection And Energy Asset Allocation, Elizabeth Trader

Graduate Studies Theses and Dissertations 2026

Existing power outage datasets lack the spatial and temporal resolution required for neighborhood- level risk assessment, and conventional energy system design optimizes for cost without accounting for community-level demand - resulting in inefficient and inequitable asset de- ployment. This dissertation presents IONCORTEX, a framework integrating three technical contributions: a heterogeneous sensor fusion pipeline combining social media signals with municipal infrastructure records for intersection-level outage detection at six-hour tempo- ral resolution, maintaining detection capability during telecommunications disruptions; a techno-economic analysis pipeline evaluating photovoltaic, battery storage, hydrogen, and diesel portfolios using NREL’s System Advisor Model with Monte Carlo uncertainty quan- tification; and …

Using Inferences From Natural Language Narratives To Improve Video Question Answering, Hoang Bao Truong

Graduate Studies Theses and Dissertations 2026

The purpose of this thesis is to examine how structured narrative representation and reasoning strategies jointly affect the performance of Video Question Answering (VideoQA). Although recent advances in large multimodal and language models have improved video description and retrieval, causal and counterfactual reasoning remain challenging. This thesis studies an inference-only pipeline in which videos are converted into natural-language narratives, and those narratives may optionally be transformed into a structured NarrativeML format before multiple-choice questions are answered without task-specific fine-tuning. NarrativeML is a machine-readable narrative representation that explicitly encodes entities, events, and their causal and temporal relations. Three representational contexts are …

Perceptions Of High School Students’ Sports Participation And Potential Impact On Post-Secondary Involvement, Anthony J. Wishart

Graduate Studies Theses and Dissertations 2026

This dissertation examined the shifting culture of youth sports in the United States and its impact on academic motivation among adolescent student athletes. The study utilized Self-Determination Theory (SDT) as a framework. Traditionally, youth sports have helped students with personal growth and academic success. However, the contemporary emphasis on early sport specialization and the decline of opportunities in nonrevenue male sports are part of broader cultural shifts and require deeper exploration.

This study investigated the relationship between sport specialization among high school male junior and senior student athletes and their levels of academic motivation, as well as the consequences of …

Ecological And Evolutionary Responses To Environmental Change In Two Large North American Mammals, George Zaragoza

Graduate Studies Theses and Dissertations 2026

Climate change and urbanization are resulting in rapid shifts in ecosystems. The effects of these changes are complex, and understanding how species respond is critical for predicting their impacts on genetic diversity and evolution, as well as changes in habitat suitability. Species can respond to these changes in two major ways: through behavioral or genetic adaptation, or by moving to more suitable habitat as conditions change. Adaptive genetic change, in particular, can support behavioral and physiological responses that enable species to persist in novel or changing environments, and understanding these changes can help predict how species will respond to anthropogenic …

Voltage Stability Enhancement Of Large Load Interconnections Using Syncronous Condensers, Muhammad Ibrahim Abbas

Graduate Studies Theses and Dissertations 2026

The rapid integration of hyperscale data centers as large, concentrated loads presents a growing voltage stability challenge in grids weakened by synchronous generator retirement and increasing inverter-based resource penetration. This work proposes a Jacobian-based sensitivity framework for systematically identifying voltage-critical buses and optimally siting synchronous condensers as voltage support resources. A voltage-weighted sensitivity index, extracted from the full Jacobian inverse, is introduced to combine network-wide reactive coupling strength with observed voltage drops into a single deployable placement criterion. Validation on IEEE 14-bus and 30-bus test systems under multiple loading scenarios demonstrates that the proposed criterion consistently identifies the correct placement …

Pseudo-Boiling Of Supercritical Co2 In A Parallel-Flow Microchannel And A Micro-Jets Impingement Device And Single-Phase And Two-Phase Heat Transfer Of Subcritical Co2 Jets, Pranzal Ahmed

Graduate Studies Theses and Dissertations 2026

Carbon dioxide (CO2) is gaining attention as a low-toxicity, zero-ozone-depletion refrigerant with a global warming potential of 1, making it an attractive alternative to synthetic HFCs/HFOs. Near its critical point, CO2's thermophysical properties change sharply with small shifts in temperature and pressure — a behavior that can be exploited to enhance heat transfer in trans-critical power cycles and electronics cooling. This dissertation experimentally investigates heat transfer during the pseudo-boiling of supercritical CO2 in a parallel-flow microchannel and a micro-jet impingement device, alongside CO2 flow boiling and single-phase water heat transfer in micro-jet impingement. Using microfluidic devices instrumented with embedded resistance …

Effects Of Back-Pressure On Pseudo-Shock Systems, Emil C. Alunno

Graduate Studies Theses and Dissertations 2026

The isolator of a scramjet engine houses a pseudo-shock, a compressive flow structure that raises the static pressure and decelerates the incoming supersonic flow for efficient combustion while shielding the inlet from the elevated pressure downstream. Under sufficient back pressure the leading shock bifurcates and forms a shock train followed by a shockless mixing region, and the resulting system oscillates even under nominally steady conditions; this unsteadiness distorts the flow, can drive the pseudo-shock out of the isolator and unstart the inlet. This thesis experimentally examines how a pseudo-shock in a constant-area isolator at a measured entrance Mach number of …

Did They Think I Was Rude? The Emotional And Relational Consequences Of (In)Congruence Between Perpetrators’ Self- And Meta-Perceptions Of Workplace Rudeness, Nicholas C. Andriese

Graduate Studies Theses and Dissertations 2026

Workplace rudeness negatively impacts employees and costs organizations millions of dollars each year. Although much is known about the consequences of workplace rudeness, little is known about how perpetrators make sense of and respond to their (potentially) rude behavior. In this dissertation, I propose that perpetrators consider not only their self-perceptions of rudeness, or how rude they believe their actions were, but also their meta-perceptions of rudeness, or their beliefs about how rude another person perceived them to be. Because rudeness is subjective and people vary in their perceptual accuracy, self- and meta-perceptions of rudeness are unlikely to consistently …

Numerical Investigation Of Reacting Flow In Pmma-Fueled Solid Fuel Scramjet Combustors Under Experimental Test Conditions, Hunter Bassett

Graduate Studies Theses and Dissertations 2026

A simplified steady RANS-based numerical study of reacting flow in solid-fuel scramjet combustors is presented to evaluate the ability of commercial CFD frameworks to reproduce key features observed in experimental test sections. The work focuses on solid PMMA fuel in two supersonic combustor configurations: a cavity-assisted flameholding combustor and a variable-angle diverging combustor. The cavity combustor is analyzed as a baseline case and results are compared directly with experimental data. Three combustor geometry states corresponding to ignition, early-burning, and steady-burning conditions are investigated. Meshes are assessed through a systematic grid refinement method to establish grid independence. A novel variable-angle diverging …

Fgf19 As A Colorectal Cancer Serum Biomarker And Fgfr4 As A Mediator Of Anti-Her2 Resistance In Breast Cancer, Jordan Beardsley

Graduate Studies Theses and Dissertations 2026

The fibroblast growth factor 19 (FGF19)-fibroblast growth factor receptor 4 (FGFR4) signaling pathway regulates hepatic metabolism, bile acid (BA) synthesis, and hepatocyte proliferation. This signaling axis also is implicated in promoting tumor progression, therapeutic resistance, and metastasis in certain cancers.

In colorectal cancer (CRC) there is a critical need for non-invasive biomarkers for disease detection and monitoring. We identified FGF19 as a candidate CRC serum marker through meta-transcriptomics and found FGF19 to be expressed and secreted by CRC cell lines. Tumor-derived FGF19 was detectable in mouse serum at levels correlating with tumor volume in a subcutaneous xenograft model. RNA sequencing …

Sensory And Emotional Impacts On Modern Consumer Experiences, Winter E. Bland

Graduate Studies Theses and Dissertations 2026

This dissertation comprises two essays examining how environmental and psychological stimuli shape consumer experience, attitudes, and cognition. The first essay investigates the joint influence of scent temperature (warm versus cool) and scent arousal (stimulating versus relaxing) on experiential attitudes and cognitive performance in digitally mediated consumption environments. Across multiple lab experiments with biometric validation, findings reveal that these two scent dimensions interact to shape downstream outcomes. Warm, low-arousal scents (e.g., vanilla) enhance consumers' experiential evaluations of digital interactions but do not improve task performance, whereas cool, high-arousal scents (e.g., peppermint) boost cognitive efficiency and accuracy but do not elevate experiential …

An Exploration Of The Professionalization Of Graduate Students Using Rhetorical Theory, Jennifer M. Crowell

Graduate Studies Theses and Dissertations 2026

This qualitative study examines the professionalization of graduate students as a rhetorically mediated and relational process of identity development within an interdisciplinary doctoral program. While existing scholarship emphasizes institutional structures and formal mechanisms of professional preparation, less attention has been given to how graduate students experience professionalization at the individual level. This study addresses that gap by exploring how students interpret expectations, use rhetorical strategies, and construct professional identities across multiple disciplinary contexts.

Grounded in organizational rhetoric and community of practice theory, the study investigates how graduate students in the Texts & Technology Ph.D. Program at the University of Central …

Vaccine Hesitancy In Arabic Discourse: A Multi-Method Social Media Study, Nada Dimashkieh Chehab

Graduate Studies Theses and Dissertations 2026

Vaccine hesitancy — the state of uncertainty about vaccination — poses global public health challenges, undermining efforts to prevent infectious diseases. It is also a contextual phenomenon, shaped by social and political forces. While survey-based research on vaccine hesitancy is abundant both globally and in the Arab world, humanities-oriented approaches using discourse analysis remain limited especially in Arabic on social media: some have tracked trends on Twitter, but virtually none have done so on Facebook. This dissertation addresses these gaps through a multimethod design combining Textual and Trend Analyses and Critical Discourse Study. It examines vaccine-related trends and discourses among …

Deciphering Ultrafast Photoinduced And Photocatalytic Reaction Dynamics On Oxide Surfaces: Direct Detection Of Radical Intermediates, Fragment Trapping, And Carbon–Carbon, Carbon–Oxygen, And Carbon–Hydrogen Bond Formation Pathways, Aakash Gupta

Graduate Studies Theses and Dissertations 2026

Understanding photoinduced reactions at solid interfaces is essential for advancing heterogeneous photocatalysis, surface photochemistry, and energy conversion technologies. This dissertation investigates the ultrafast dynamics of reactive intermediates, fragment trapping, and radical-mediated bond formation on oxide surfaces using time-of-flight mass spectrometry in conjunction with femtosecond pump-probe spectroscopy. Various experimental findings are validated through collaborations via density functional theory (DFT). By combining temporal, mass, and energy-resolved measurements, this work provides molecular-level insight into the elementary processes governing light-driven surface reactions. The photodissociation dynamics of CH₃I adsorbed on TiO₂(110), TiO₂(100), and amorphous silicon oxide surfaces are examined …

Strategic Signaling Or Structural Friction?: How Ai Disclosure Moderates Resource-Performance Dynamics In Hotels And Restaurants, Jaewan Heo

Graduate Studies Theses and Dissertations 2026

Artificial intelligence (AI) has become an increasingly important strategic issue in the hospitality industry. While prior research has primarily examined AI as an operational technology that improves efficiency and service delivery, less attention has been paid to how AI-related disclosures influence investor evaluations of firm resources. This dissertation investigates whether AI-related disclosures moderate the relationship between organizational resources and financial performance in publicly traded hospitality firms.

Drawing on signaling theory and the resource-based view, this study conceptualizes AI disclosures as strategic signals that shape investor perceptions of firm capabilities and future value creation. Firm-level financial data were obtained from Compustat …

A Case Study Examining Organizational Influences On Student Teacher Placement In K-12 Classrooms, Rachel L. Ickes

Graduate Studies Theses and Dissertations 2026

Student teaching is a prominent and required learning experience in most teacher education programs. The learning that takes place in student teaching blends pedagogy with practice. However, not all student teaching placements provide positive learning experiences for student teachers. This descriptive case study examines the organizational factors that affect the process of student teacher placement at K-12 classroom sites by one teacher education program. For this case study, one teacher education program in the southeastern United States was selected as the case site, and the case for this study is the process of student teacher placement. Semi-structured interviews, observation, and …

Integrated Corridor Management Framework For Severe Freeway Incidents, Sanjida Afroz Iqra

Graduate Studies Theses and Dissertations 2026

Traffic incidents are a major source of non-recurrent congestion on urban freeways, generating substantial mobility, safety, and economic impacts. Severe incidents that block multiple or all travel lanes are particularly disruptive because they degrade freeway operations and propagate congestion onto surrounding arterials. Effective Integrated Corridor Management (ICM) requires the ability to identify severe incidents, estimate their network-wide impacts, and anticipate the traffic conditions and driver behaviors that contribute to instability. This dissertation develops a data-driven ICM framework to address these challenges using real-world incident, crash, detector, and connected vehicle data from major Central Florida corridors, including I-4 and SR-417. The …

Investigating The Anti-Apoptotic Properties Of The N-Terminus Of The Chlamydia Trachomatis Effector Tarp, Kasey S. Jordan

Graduate Studies Theses and Dissertations 2026

As the most prevalent bacterial STI in the United States and leading cause of infection-related blindness worldwide, the obligate intracellular bacteria, Chlamydia trachomatis (Ct), poses a significant threat to public health. As an obligate intracellular bacteria, invasion of the host cell is a crucial step in Chlamydia’s developmental cycle. To drive invasion, Ct injects prepackaged effectors into the host cell using a T3SS. An early Chlamydial effector, translocated actin recruiting phosphoprotein, or Tarp, interacts with host cell actin to promote invasion, mediated via Tarp’s C-terminal region. Although the function of Tarp’s C-terminus is well defined, the Tarp’s N-terminus …

The Odyssey Of Emotion Regulation In Extremis: How Challenges Lead To Team States Through Regulation And Psychological Safety In Ice, Andres Kaosaar

Graduate Studies Theses and Dissertations 2026

Isolated, confined, and extreme (ICE) teams experience challenges that require continuous emotional adaptation. Although emotion regulation (ER) has been recognized as critical for functioning in these contexts, little is known about how specific challenges shape regulatory responses, how team climate influences those responses, and how individual regulation accumulates into team-level outcomes. This dissertation develops and tests a multilevel framework linking challenge exposure, perceived psychological safety, individual ER, team emotions, and team viability in space analog environments. Data were collected from 36 crews (N = 184) participating in two-week missions at two space analog stations, yielding 2,577 daily observations and …

The Impact Of Criminal Justice System Contact On Adolescents In The U.S.: Prescription Drug Misuse, Marijuana Use, Health Outcomes, And Demographic Characteristics, Fadime Gokce Karaaslan

Graduate Studies Theses and Dissertations 2026

Criminal justice system (CJS) contact remains a pervasive feature of social life in the United States, with both direct and indirect consequences for adolescents and their families. Although previous research has explored the consequences of direct CJS contact, less is known about how indirect or vicarious contact affects adolescents’ well-being and substance use. Drawing on data from the Future of Families and Child Wellbeing Study (FFCWS), this study investigates the association between parental incarceration and vicarious police stops, defined as police stops involving parents, siblings, friends, neighbors, or other social ties, and adolescent well-being. Findings indicate that CJS contact is …

Two Studies Exploring Signal-Environment Fit In Ai-Assisted Managerial Decision-Making Under Uncertainty, Oleksandr Kondrachuk

Graduate Studies Theses and Dissertations 2026

This dissertation examines how the fit between the characteristics of artificial intelligence systems and the uncertainty environment shapes managerial reliance on AI advice. Organizations increasingly deploy different AI systems, such as predictive and generative, to support management accounting decisions. However, the accounting literature has mainly treated AI as a single undifferentiated entity. This dissertation addresses this gap through two related studies. In the first study, drawing on signaling theory and ecological rationality, I develop a signal-environment fit framework proposing that the reliance on a certain AI system depends on the match between system characteristics (input, process, output) and uncertainty characteristics. …

Advances In Active And Passive Integrated Photonic Devices On Thin-Film Lithium Niobate, Pooja S. Kulkarni

Graduate Studies Theses and Dissertations 2026

Thin-film lithium niobate (TFLN) has emerged as a powerful platform for integrated photonics, combining the exceptional electro-optic, nonlinear, and optical properties of bulk lithium niobate with the scalability and compactness of planar nanophotonic technologies. Building on these principles, advanced device architectures such as adiabatic dichroic filters have demonstrated exceptional spectral performance spanning over two octaves of bandwidth on the TFLN platform. Beyond reciprocal devices, it also offers promising pathways toward integrated nonreciprocal components. By leveraging broadband filtering structures and advanced nonlinear photonic design strategies, compact and monolithic optical isolators can be envisioned without relying on traditional magneto-optic materials. In the …

Internalized Shame, Self-Focused Attention, And Post-Event Processing In Everyday Social Anxiety, Wooje Lee

Graduate Studies Theses and Dissertations 2026

The purpose of this study was to investigate how emotional processes, represented by internalized shame and daily shame (from the emotion-focused therapy model), and cognitive processes, represented by self-focused attention and post-event processing (from cognitive-behavioral models), operate on a daily basis to contribute to social anxiety. Data collected from a sample of 39 individuals with high social anxiety via an online survey and daily diaries was analyzed using multilevel path analysis. The results showed that, at the within-person level, daily shame experienced during an important social interaction influenced self-focused attention during that same interaction and subsequent post-event processing, which in …

Hunter. Hunted. Human: Warfighters' Emotional Responses To Weapons In Tactical & Strategic Context, Simon Mace

Graduate Studies Theses and Dissertations 2026

Human emotional responses to weapons have long been assumed to be relatively parsimonious, comprised predominately of aggression, anxiety, and fear responses. However, most research on this weapons effect has focused on civilians – who are notably more likely to be targeted by than to employ weapons. So, there is reason to speculate that emotional responses to weapons vary more than previously believed. This is significant for three reasons. First, positive emotional responses generate more desirable combat behaviors, specifically the willingness to engage adversaries. Second, negative emotional responses catalyze an unpredictable range of behaviors, many of which are tactically and operationally …

The Diversity Of Flavivirus Antibody Dependent Enhancement (Ade) Profiles From A Pediatric Cohort In Mexico, Maiesha Samiha Mahmood

Graduate Studies Theses and Dissertations 2026

The Aedes mosquito-borne flaviviruses Zika (ZIKV) and dengue (DENV-1-4) cause an estimated 400 million annual infections globally and pose an increasing threat to public health. Typically, individuals infected with ZIKV or a DENV serotype generate neutralizing serotype-specific antibodies and non-neutralizing, cross-reactive antibodies that bind multiple flaviviruses. Upon secondary heterotypic infection, pre-existing antibodies can either protect or exacerbate disease through antibody dependent enhancement (ADE). ADE occurs when non- or sub-neutralizing concentrations of cross-reactive antibodies facilitate viral uptake into FcγR-bearing myeloid cells, enabling infection of otherwise non-permissive cells and driving severe disease. To date, ADE has not been characterized at a population …