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Shock Tube Speciation Analysis Of Hydrocarbon Mixtures Relevant To Solid Fuel Combustion, Diego N. Ruiz Pena

Graduate Studies Theses and Dissertations 2026

Solid Fuel Ramjets (SFRJs) are often used in tactical applications due to their simplicity, robustness, and reliability. No moving parts, atmospheric oxidizer usage, and scalable fuel grain designs make them a great solution for compact, high-speed air-breathing propulsion systems. SFRJs operate by compressing incoming air through a fixed geometry inlet and directing it over a regressing solid fuel surface, where pyrolysis gases are released and transported downstream to the combustion chamber where thrust is generated. Hydroxyl-terminated polybutadiene (HTPB) is a commonly used fuel binder in SFRJ systems due to its high energy density, stable combustion behavior, and ease of processing. …

Multibody Acausal Framework For Structural Dynamics Of Offshore Support Structures With Hydroelasticity And Soil-Structure Interaction, Saad Rahman

Graduate Studies Theses and Dissertations 2026

Offshore energy systems present significant challenges in support structure design due to their scale and the strong coupling between aerodynamic, hydrodynamic, and structural subsystems. These interactions make traditional sequential modeling approaches inefficient for design exploration. Acausal modeling frameworks address this limitation by enabling direct integration of coupled subsystems without reformulating governing equations, improving computational efficiency while preserving physical fidelity. This supports rapid exploration of large design spaces, accelerates iteration cycles, and shortens the path from concept to deployment.

This thesis develops and validates an acausal multibody elastodynamics model for offshore support structures. The framework includes structural flexibility to capture member-level …

Study Of Compressibility Of Flames In Scramjet Combustors, Anirudh Ranganathan

Graduate Studies Theses and Dissertations 2026

Viable forms of propulsion for practical hypersonic flight are of great interest in modern times, of which supersonic combustion ramjets(scramjets) are a very advantageous option. Compared to ramjets, which are severely limited by increasing total pressure loss and dissociation effects, scramjets offer a much more efficient form of propulsion in the Mach 6 – 8 regime. Despite this, a common and unmitigated issue facing scramjet technology is scramjet unstart.

Prior investigations researching scramjet unstart have elucidated global heat release considerations in relation to total fueling or combustion modes as a result of global heat release . Minimal work has been …

A Frequency-Dependent Hydrodynamic Modeling Framework For Offshore Platforms With Optimization-Based Parameter Identification, Md. Rafid-Ul Haque Sakif

Graduate Studies Theses and Dissertations 2026

Accurate prediction of hydrodynamic loads on offshore platforms requires drag coefficients that adequately capture their dependence on wave frequency. However, conventional implementations of Morison’s equation generally assume constant drag coefficients across the entire frequency spectrum, which can lead to inaccuracies in predicting platform responses under complex sea-state conditions. To address this limitation, this study proposes a frequency-dependent hydrodynamic modeling framework in which the platform response is decomposed into distinct frequency regions, specifically low-frequency and high-frequency components. Separate drag coefficients are assigned to each region to better represent the underlying flow physics. The decomposition is achieved using filtering techniques in the …

Design And Characterization Of A Jet Nozzle Using Particle Image Velocimetry, Valerie K. Rodriguez

Graduate Studies Theses and Dissertations 2026

This paper presents the design and experimental characterization of the jet exit velocity from a supersonic nozzle injecting into a low-pressure vacuum chamber using Particle Image Velocimetry (PIV). The PIV method is employed to overcome limitations encountered in prior experiments characterizing a jet-in-crossflow, such as qualitative shock visualization and insufficient data on jet exit properties. The previous set of experiments used Classical Schlieren to visualize the flow as well as emission measurement with IR detectors. For the fuel injection cases, particular emphasis is placed on preventing condensation within the injection line and at the nozzle exit due to under expanded …

Defect-Guided And Energy-Driven Unfolding With Learning-Based Strategies: From Geometries With Compact Refolding To Garments, Shah Wasif Sazzad

Graduate Studies Theses and Dissertations 2026

Unfolding and folding are related geometric and mechanical transformations fundamental to structural applications. Particularly, unfolding curved surfaces is important for deployable structures, garment pattern generation, etc. A central challenge is minimizing geometric distortion between a surface and its unfolded counterpart avoiding overlaps. As regions of lower Gaussian curvature typically produce less distortion during flattening, identifying curvature distribution becomes essential. Topological defects in a particle assembly on a surface in its minimum interaction-energy configuration indicate regions of concentrated curvature. In this work, an unfolding method is proposed that segments the surface using defects' location. Cutlines connecting the defects isolate lower curvature …

Modeling Hazard Perception Learning In Novice Drivers With Autism: A Multimodal Simulation-Based Study, Erik J. Sand

Graduate Studies Theses and Dissertations 2026

Young drivers with autism spectrum disorder (ASD) often demonstrate difficulties with road-surveillance behaviors such as scanning ahead, monitoring mirrors, and identifying emerging hazards. These challenges can increase crash risk, particularly for adolescents with limited driving experience. This study explored whether a simple, video-game–based hazard-training program could improve hazard detection performance, visual scanning, and self-regulation in this population. Five participants aged 15–18 years, each identified by a parent as having ASD and possessing either a learner’s permit or no license, completed sequential Baseline, three Treatment, and Withdrawal phases using the SpeedLimit driving simulation. The study employed a single-case experimental design with …

Data-Driven Seismic Site Classification Using Earthquake And Microtremor Horizontal-To-Vertical Spectral Ratios, Sanidhya Sharma

Graduate Studies Theses and Dissertations 2026

The prevailing seismic site classification parameter, the time-averaged shear-wave velocity in the upper 30 meters (V_S30), provides an incomplete representation of site conditions, neglecting deeper geology, impedance contrasts, and resonance phenomena. This thesis developed and validated a data-driven framework for seismic site classification based on the full spectral shape of Horizontal-to-Vertical Spectral Ratio (HVSR) curves combined with unsupervised machine learning, through two complementary research studies. Research 1 applied K-means clustering to earthquake-based HVSR (eHVSR) data from 3,186 ground motion stations across California and adjacent regions, identifying four physically distinct site clusters, characterized by low-frequency, very-low-frequency, high-frequency, and …

Bond Behavior Of Uhpc-Nsc Interfaces For Bridge Deck Repair Under Flexural Loading, Larissa Santiago La Banca

Graduate Studies Theses and Dissertations 2026

The use of ultra-high performance concrete (UHPC) has increased due to its superior mechanical properties and strong bond with normal-strength concrete (NSC). It is widely used as a repair material, particularly in bridge decks, where maintenance remains a challenge. However, the interface between UHPC and NSC is often the weakest region of the composite system and requires careful evaluation.

This study investigates the bond behavior between UHPC and NSC using different surface preparations, test setups, and UHPC materials. The experimental program included unreinforced beams with vertical interfaces tested under three- and four-point flexural loading, and reinforced slabs with horizontal interfaces …

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 …

Experimental Characterization Of Obstacle-Driven Ddt And The Performance Of Relief Dump Tanks In Detonation Systems, Bryan Suarez

Graduate Studies Theses and Dissertations 2026

This study investigates the lifecycle of a detonation event in a modular detonation
tube facility. It focuses on the mechanisms of deflagration-to-detonation transition
(DDT) and the effectiveness of a pressure relief system. With a stoichiometric
hydrogen-oxygen mixture, the research aims to characterize the effect of
interchangeable turbulator obstacles on the DDT process. By varying blockage
ratios and obstacle geometries in the pre-detonation section. This study identifies
how physical characteristics influence transition efficiency. The experimental data
collected includes pressure spikes and wave speed which were then used to
validate against the Chapman-Jouguet (CJ) theory at initial pressures of 350 Torr
and …

Toward Urban-Scale Liquefaction Hazard Analysis: Evaluation And Optimization Of Cpt-Based Lateral Displacement Assessment, Varun M. Singh

Graduate Studies Theses and Dissertations 2026

Liquefaction-induced lateral spreading is a major type of earthquake-induced ground failure hazard and poses a significant threat to infrastructure systems. While semi-empirical methods, such as Lateral Displacement Index (LDI), have been developed to estimate lateral spreading displacement (LSD), their efficacy for regional-scale liquefaction hazard assessment remains unknown. This study evaluates and improves the LDI method for urban-scale seismic hazard assessments using a comprehensive dataset consisting of 1,713 Cone Penetration Test (CPT) case histories from the 2011 Christchurch, New Zealand earthquake, and high-resolution topographic data. Comparing the predicted LSDs and ground-truth observations from both field investigations and remote-sensing surveys reveals that …

Code-Switching, Identity-Shifting, And Identity Distress Among Black Undergraduate Women Attending Predominantly White Institutions, Erin Smith

Graduate Studies Theses and Dissertations 2026

Code-switching (altering language or speech) and identity-shifting (modifying appearance or behavior) are adaptive strategies often used by individuals from marginalized groups to navigate environments shaped by dominant cultural norms. Although these behaviors are commonly discussed in qualitative literature, relatively few quantitative studies have examined their psychological correlates among Black undergraduate women attending predominantly White institutions (PWIs). These behaviors may function as coping strategies in response to racialized and gendered expectations, yet the psychological implications of these strategies remain understudied. The present study examined the relationships among identity distress, code-switching, identity-shifting, and gendered racial identity centrality within a diverse sample of …

Thermomechanical Modeling Of Transpiration Surfaces For Hypersonic Propulsion, Spencer D. Smith

Graduate Studies Theses and Dissertations 2026

Hypersonic flight vehicles are a promising form of high speed passenger transport and efficient space access architectures. However, they are fundamentally a thermally limited technology. High heat fluxes exceeding 10 MW/m2 and gas temperatures between 3000-4000K can be found both within the engine, and on the outer surface. Current conventional engineering materials are non-viable at these conditions. In order to make these materials viable, active cooling strategies could be utilized. One particularly promising type is transpiration cooling, where a coolant is diffused through a porous surface. Although researched heavily in the 1960s, adoption is still minimal. Part of the reason …

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 …

Chirpi - Implementing And Analyzing The Chirp Communication Algorithm On Esp32 Hardware, Calvin Vanwormer

Graduate Studies Theses and Dissertations 2026

This work presents the implementation and experimental evaluation of the CHIRP communication algorithm on resource-constrained ESP32-S3 microcontrollers, bridging the gap between simulation-based validation and real-world deployment. CHIRP is a lightweight, fully decentralized peer-to-peer protocol designed for IoT networks with dynamic node membership, enabling runtime node join and leave operations without centralized coordination or global reconfiguration. The implementation comprises two main components: C-based node firmware running on FreeRTOS [1, 2], which implements the full CHIRP protocol including peer discovery, round-robin pairing, and firefly-inspired phase synchronization, and a Python-based experiment controller that orchestrates network experiments and collects per-node metrics without influencing protocol …

High Intensity Ablation By Laser Filaments At Standoff Distances, Owen Thome

Graduate Studies Theses and Dissertations 2026

The high-power densities delivered to a target material by a laser allow for melting and vaporization to occur, a process called laser ablation. At higher intensities, plasma formation occurs and more complex material removal mechanisms take place. As laser power increases, nonlinear effects occur during propagation. One such effect, Kerr self-focusing, leads to beam collapse and ionization, resulting in a channel of plasma and region of high intensity light referred to as a laser filament. Filaments carry intensities on the order of 10¹³ W/cm² to significant distances without the use of large-scale focusing optics. Laser filament ablation is …

Between The Living And The Dead, Leona Strong

Graduate Studies Theses and Dissertations 2026

Between the Living and the Dead is a collection of short stories and flash fiction that explores loss, generational abuse, abandonment, the sometimes brutal power of familial ties, and love in its many forms—both good and evil. This thesis aims to tease out, in the reader, moments of reflection, compassion and revelation. “Falling,” centers on a mother’s grief after her son dies by suicide and her attempt to move beyond perceived culpability and shame. She does this by jumping from a plane to embody his last moments and make the same decision…to live or to die. “And Baby Makes One,” …

Advancing Multi-Modal Learning, Swetha Sirnam

Graduate Studies Theses and Dissertations 2026

Multimodal learning aims to develop systems that understand and reason across multiple sources of information such as images, videos, audio, and text. These capabilities are central to applications including visual search, digital assistants, robotics, and visual question answering. Despite recent progress in multimodal large language models, current approaches struggle to capture the structured complexity of real-world visual data. Fine-grained visual details are often lost during multimodal alignment, models frequently fail to capture nuanced human intent, and existing methods remain limited in understanding long-form videos with complex temporal dynamics. Furthermore, many evaluation benchmarks rely heavily on explicit visual cues, which can …

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 …

Federated Learning In The Era Of Foundation Models, Guangyu Sun

Graduate Studies Theses and Dissertations 2026

The emergence of large-scale foundation models has reshaped computer vision and multi-modal learning, but their substantial computational and communication demands pose significant challenges for deployment in federated learning (FL) systems. Federated learning enables collaborative model training across decentralized clients without sharing raw data, offering strong privacy guarantees. However, adapting foundation models in FL remains difficult due to communication bottlenecks, heterogeneous data distributions, limited device resources, and scarce labeled data. This dissertation presents a unified line of research that addresses these challenges through four complementary frameworks, progressively advancing the efficiency, personalization, and practicality of foundation model adaptation in federated settings.

First, …

Oblique Detonation Waves In Internal Axisymmetric Converging Flow, Zachary P. White

Graduate Studies Theses and Dissertations 2026

Detonative combustion offers significant thermodynamic advantages for high‑speed propulsion, motivating the development of detonation‑based combustors for hypersonic flight. Among these, oblique detonation wave (ODW) engines require extremely high combustor velocities to achieve steady wave stabilization. While most prior experimental and numerical studies have focused on planar two‑dimensional geometries, axisymmetric combustors offer practical benefits for hypersonic vehicle integration and may influence achievable pressure gain. However, the effects of inward‑turning axisymmetric compression on ODW formation and performance remain largely unexplored. This work presents an experimentally stabilized ODW formed on an internal axisymmetric converging ramp. Experiments were conducted in a high‑enthalpy blowdown wind …

The Effects Of Episodic Facilitation And Immersion On Memory Formation During Learning Of An Exterior Preflight Inspection Procedure, Nathan A. Sonnenfeld

Graduate Studies Theses and Dissertations 2026

This research examined the use of episodic facilitation—instructional elements aligned with episodic memory (EM) processes—to affect learners’ memory of simulation training for an aviation procedure. Despite its assumed benefits in industry and theory, virtual reality (VR) has shown limited advantages over conventional media for training procedures, in part because prevailing frameworks emphasize semantic and procedural outcomes, leaving memory of training experiences as events underexamined. To address this gap, this work advances human factors research by examining EM as a design consideration, an outcome, and an explanatory mechanism for how simulation training experiences are remembered. Grounded in theories of EM and …

Photothermal Excitation And Optical Interferometric Readout Of Mos2 Nanomechanical Resonators, Sadia Afrin

Graduate Studies Theses and Dissertations 2026

Two-dimensional (2D) materials have emerged as promising candidates for nanoelectromechanical systems (NEMS) due to their exceptional mechanical, optical, and electrical properties. Among these materials, molybdenum disulfide (MoS2) has attracted considerable interest for nanomechanical resonator applications because of its low mass density, high mechanical strength, and semiconducting nature. This thesis presents the fabrication, theoretical modeling, and experimental characterization of suspended MoS2 drumhead resonators. The devices were fabricated by mechanically exfoliating MoS2 flakes from bulk MoS2 crystals and transferring selected flakes onto pre-patterned substrates using a dry-transfer process. Mechanical resonance was excited through photothermal actuation using a modulated blue laser, while device …

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 …

Bowtie Antenna-Coupled Bi₂Te₃–Sb₂Te₃ Thermoelectric Detector For Millimeter-Wave Radiation, Rumana Zahir

Graduate Studies Theses and Dissertations 2026

We explore the development of antenna-coupled thermoelectric detectors for long-wavelength radiation using sputtered bismuth telluride (Bi₂Te₃) and antimony telluride (Sb₂Te₃) thin films. Detection in the infrared, millimeter-wave, and terahertz regimes is critical for sensing, imaging, and energy applications; however, many existing detectors rely on cryogenic operation, exhibit narrow spectral response, or require complex material systems. In this work, we investigate the feasibility of reliable, room-temperature long-wavelength detection using microfabricated thermoelectric thin films integrated with antenna structures. A systematic full-factorial experimental approach was employed to determine how sputtering parameters and post-deposition annealing influence …

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 …

Soil Texture And Organic Matter Influence Hydraulic Performance Of Stormwater Infiltration Systems Across Antecedent Moisture Conditions, Laura E. Andrade Barron

Graduate Studies Theses and Dissertations 2026

Stormwater infiltration systems are widely used to improve urban stormwater management by promoting drainage and groundwater recharge while treating nonpoint source pollution such as nutrients in surface runoff. Nutrient removal and hydrologic performance of these systems are closely coupled and both are dependent on characteristics of underlying soils. In this study, laboratory flow-through experiments were conducted using 30 intact cores taken from six soil types with different textures (0.99-16.63% clay content) and organic matter contents (OMC 0.44-93.3%). Measured cumulative fluxes from laboratory experiments were used to calibrate numerical models simulating flow through porous media (HYDRUS-1D). Calibrated models were used to …

Watch Your Step, Mind The Crowd: Socially Compliant Navigation In Unstructured Environments, Jack Vice

Graduate Studies Theses and Dissertations 2026

Autonomous mobile robots increasingly operate in complex real-world environments characterized by uneven terrain, dynamic obstacles, and human presence. This dissertation addresses the fundamental challenge of developing adaptive navigation strategies that enable robots to safely and effectively traverse unstructured outdoor environments including construction sites, agricultural fields, and disaster areas while maintaining social compliance around people. We advance this capability through five complementary contributions that collectively target dynamic, unstructured, human-occupied environments. First, we demonstrate evolutionary optimization of legged mobility for uneven terrain. Second, we propose using a spatiotemporal autoencoder to learn the temporal dynamics of moving people and objects. Third, we introduce …