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The Influence Of Rainfall And Land Cover Change On Streamflow Variability In Eastern Florida Watersheds, Brynn Romberger

Theses and Dissertations

Streamflow in Florida watersheds is influenced by both land cover change and rainfall variability, but separating their contributions is difficult because both have changed over recent decades. This study evaluated rainfall trends and land cover change to determine which better explains flood and drought threshold exceedance across 27 USGS streamflow gauges within the St. Johns River Water Management District (SJRWMD) from 1985 to 2025. Streamflow was characterized using change-point, trend, and variability analyses with a six-threshold exceedance framework. Land cover was quantified using the National Land Cover Database (NLCD), rainfall characteristics were derived from the Analysis of Records for Calibration …

Helicopter Pilots’ Safety Behaviors: Identifying Factors That Affect Risk Perception Among Helicopter Pilots, Khaled J. Alzaabi

Theses and Dissertations

Helicopter operations frequently take place in complex, high-risk environments, where pilots continuously assess hazards and make critical decisions under pressure. Despite standardized procedures, regulations, and training designed to enhance safe operations, helicopter pilots may perceive risk differently when encountering similar flight situations. Understanding the factors that influence helicopter pilots’ perception of risk is essential for improving helicopter operation safety.

The purpose of this study was to investigate the effect of various factors on risk perception among helicopter pilots. Using an explanatory correlational design, the study assessed whether helicopter pilots’ demographics, flight experience, and affective domain factors explain differences in their …

Secure And Compassionate Dementia Care: Non-Intrusive Remote Monitoring Of Falls, Wandering, And Agitation, Awan-Ur- Rahman

Master's Theses

Alzheimer’s disease and related dementias (ADRD) present significant safety challenges, as affected individuals may experience falls, wandering, agitation, and a progressive decline in independence. Although continuous monitoring can enable timely intervention, many existing systems rely on cameras or wearable devices, which may introduce concerns related to privacy, comfort, and sustained use. This thesis explores privacy-preserving and non-intrusive remote monitoring through two complementary studies. The first study presents an ambient Wi-Fi channel state information framework for recognizing agitation and eight daily activities. The proposed approach translates behavioral and physiological markers commonly captured by wearable sensors into the Wi-Fi sensing domain. The …

Spatial Structure And Energy Content Of Wakes Behind Single And Arrayed Undulated Cylinders, Taiga Naomi Drucker-Boisvert, OndˇRej FerˇCák, Jérémie Auzoux, Sarah E. Smith, Zein Sadek, Rowan Moore, Christain T. Murphy, Trevor Dunt, Jennifer A. Franck, Raul Bayoan Cal

Mechanical and Materials Engineering Faculty Publications and Presentations

Biologically inspired undulated cylinder geometries significantly influence wake structure and vortex-induced vibrations in turbulent flows, yet the underlying mechanisms are not fully understood. It is further unknown how these influences extend to multi-cylinder arrays, where interacting wakes accumulate and mix. This study examines the wake characteristics of an undulated cylinder and a smooth elliptic cylinder in single- and multi-cylinder array configurations, using particle image velocimetry and proper orthogonal decomposition (POD). Relative to the smooth elliptic cylinder, the undulated geometry induces pronounced spanwise-axial variability, characterized by enhanced near-wake mean momentum and weak far-wake signatures, consistent with reduced turbulent kinetic energy. While …

Balancing War And Peace In Taekwondo Athlete Development: A Multi-Criteria Coaching Decision Support Framework Using Leadership Scale For Sports And Fuzzy Ahp, King Harold A. Recto, Hazel Jade L. Antonio, Jhyrald Anthony P. Dalida

Electronics, Computer, and Communications Engineering Faculty Publications

Coaching effectiveness is frequently evaluated through competitive outcomes, with the assumption that coaching behaviors directly influence athlete performance. This study examined the relationship between perceived coaching behaviors and individual win percentage among collegiate Taekwondo athletes using the Leadership Scale for Sports (LSS). Descriptive statistics, correlation analysis, and regression analysis were conducted across five coaching dimensions: Training and Instruction, Democratic Behavior, Autocratic Behavior, Social Support, and Positive Feedback. Results showed that none of the coaching dimensions demonstrated a statistically significant relationship with win percentage. Although coaching behaviors did not significantly predict win percentage, the findings suggest that athlete development is shaped …

Wind Effects Induced By Multivortex Tornadoes On A Low-Rise Building, Yi Zhao, Guirong Yan, Tetsuya Takemi, John Van De Lindt

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Multivortex tornadoes contain two or more subvortices that orbit within a parent vortex and can generate highly intermittent and localized near-ground wind fields. This study investigates how tornado flow structure affects wind effects on a low-rise building using large-eddy simulations. One single-vortex tornado and three multivortex tornadoes with different subvortex configurations are examined by systematically varying swirl ratio. Tornado translation is modeled using a relative-motion framework in which the building traverses the vortex field. Aerodynamic force and moment coefficients are evaluated along the traversing path. Additional stationary simulations are conducted to examine repeated load amplification associated with subvortex passages. Compared …

Microstructural Shielding And Advanced Fatigue Crack Analysis In The Presence Of Deformation Twinning, Seyed Ali Asli

All Dissertations

Design methods to mitigate fatigue failures have remained relatively stagnant, as engineers have relied on existing continuum-level models and adhered to the damage tolerance design methodology. Although damage-tolerant design has led to increased safety, extended component in-service life, and better life predictions, it still relies on maintenance routines to identify dangerous cracks. This research aims to test the hypothesis that bundles of deformation twin boundaries will increase the resistance to fatigue crack growth (FCG). Slip and twinning are two dominant mechanisms of plastic deformation in metals. Slip is more common in materials with face-centered cubic (FCC) crystal structures at room …

Efficient And Scalable Visual Computing For Nanoscale Imaging, Hao Wang

All Dissertations

Nanoscale analysis often relies on instrument-mediated scientific imaging methods to capture visual signals that are difficult to observe, interpret, or quantify through ordinary perception alone. These domains are often characterized by low signal quality, limited annotations, complex morphology, non-natural visual statistics, and strong dependence on physical acquisition processes. This dissertation focuses on efficient visual computing for nanoscale imaging, with an emphasis on the representation, reconstruction, and analysis of high-resolution scientific visual data. In our early work, we relied on rule-based algorithms and conventional machine learning methods for feature extraction. However, these approaches struggle to scale with the increasing complexity and …

Leveraging Deep Learning Recurrence And Attention Mechanisms For Flood Forecasting And Assessment, Elnaz Heidari

All Dissertations

Predicting how much water will flow in rivers and streams is important for managing floods, water supply, and the environment. Traditionally, government agencies have used complex models, such as the National Water Model (NWM), which simulate how much water moves through landscapes using physical laws and real-world data. However, recent advances in Artificial Intelligence (AI) have enabled new ways to make these predictions. This research explored whether AI-based models could predict river discharge more accurately. These AI models learn patterns from past data instead of relying only on physical rules. To find out how well they work, the AI models …

2++ Light Tensor Hybrid Meson From Qcd Laplace Sum Rules, Jason N.E. Ho, Robert Kleiv, Siyuan Lee, Stephan Narison, Tom Steele, Davidson Rabetiarivony

Faculty Work Comprehensive List

We present an analysis of the light tensor (𝐽𝑃𝐶 = 2++) hybrid meson mass and coupling from QCD Laplace Sum Rules where the next-to-leading order (NLO) perturbative (PT) corrections and the contributions of the nonperturbative (NP) condensates up to dimension-six (𝐷 = 6) are included. NLO leading-logarithms corrections due to the condensates which contribute in the chiral limit are considered. We obtain the mass 𝑀2+ = (2038 ± 190) MeV and a relatively small coupling 𝑓2+ = (10.5 ± 2.9) MeV normalized as 𝑓𝜋 = 93 MeV. Our results suggest that the 𝑓2(1950) or/and the 𝑓′ 2 (2010) may have …

Toward Risk-Informed Design Of Supercooling Heat Exchangers: Statistical Inference And Experimental Investigation Of Heterogeneous Ice Nucleation, Daniel B. Gardner

All Graduate Theses and Dissertations, Fall 2023 to Present

Ice-based cooling storage systems can reduce electricity costs and grid strain by making ice during off-peak hours and using it for air conditioning during the day. One promising design works by chilling water below its freezing point as it flows through a heat exchanger, then allowing it to freeze in a separate storage tank. The challenge is that the chilled water can freeze prematurely inside the heat exchanger itself, blocking the flow and shutting the system down. Preventing this unwanted freezing requires understanding how and where ice begins to form on surfaces, a process called nucleation.

This dissertation investigates ice …

The Role Of Roughness And Geometry In 2d Depth-Averaged Models: A Comparative Study Using Laboratory Flume Experiments, Adrienne Luymes Mckell

All Graduate Theses and Dissertations, Fall 2023 to Present

Hydraulic models are commonly used to predict how water moves through rivers and streams, helping engineers manage flood risk and design infrastructure such as bridges, culverts, and restoration projects. One challenge in these models is representing the effects of riverbed roughness, including features such as rocks, vegetation, and other obstacles that slow water flow.

This study investigated whether it is better to represent these roughness features in detail or to simplify them while still accounting for their effects. Laboratory measurements from a controlled channel experiment were used to create two computer models: one that included the detailed shape of the …

Atomic-Scale Investigation Of Functional Molecular Systems And Graphene Nanoribbons Using Scanning Probe Microscopy, A.M. Shashika D. Wijerathna

Physics Theses & Dissertations

Emerging molecular electronics, molecular devices, and carbon-based nanotechnologies increasingly rely on the precise control of molecular structures and interfaces at the atomic scale. Advancing these systems requires experimental techniques capable of resolving atomic structures, quantifying molecular behavior, and revealing the mechanisms governing nanoscale assembly. Scanning probe microscopy uniquely provides these capabilities by combining atomic-resolution imaging with local spectroscopy and manipulation. This dissertation employs ultra-high-vacuum low-temperature scanning tunneling microscopy (UHV-LT-STM) and qPlus atomic force microscopy (qPlus AFM) to address three complementary challenges: (i) atomic-scale characterization of complex supramolecular architectures, (ii) quantitative investigation of mechanically induced conformational switching of individual molecules, and …

Towards More Realistic And Practical Graph Backdoor Attacks, Jiawei Chen

Computer Science Theses & Dissertations

Graph Neural Networks (GNNs) have demonstrated remarkable performance on graph-based learning tasks and are increasingly deployed in security-critical applications. However, recent studies have shown that they are highly vulnerable to graph backdoor attacks (GBAs), where adversaries implant malicious triggers to induce targeted misclassification during inference. Despite their effectiveness, existing GBAs are often developed under unrealistic assumptions, such as focusing exclusively on simple homogeneous graphs or assuming the adversary possesses privileged access to target nodes during inference. This dissertation aims to systematically investigate and design graph backdoor attacks under significantly more realistic graph settings and adversarial constraints.

First, we investigate the …

Development Of Reduced Conflict U-Turn (Rcut) Guidance In Kentucky, Travis Thompson, Duane Thomas, Jill Asher, Jeff Jasper

Kentucky Transportation Center Research Report

A reduced conflict U-turn (RCUT) intersection eliminates left-turn and through movements from the minor road. Instead, drivers must turn right onto the main road and complete a U-turn at a downstream median opening. Recognized by the Federal Highway Administration (FHWA) as a proven safety countermeasure, RCUT intersections have reduced fatal and injury crashes 22 – 63%. Despite more than 35 RCUT intersections in operation across Kentucky, the Kentucky Transportation Cabinet (KYTC) lacked specific guidance for their planning, design, construction, and operation.

This project, conducted by the Kentucky Transportation Center (KTC) in cooperation with KYTC, addressed this gap through a comprehensive …

Practical On-Device Intelligence For Resource-Constrained Embedded And Wearable Devices, Xiao Ma

Dissertations and Theses Collection (Open Access)

Embedded and wearable devices increasingly rely on deep neural networks to support intelligent sensing applications directly on the device. However, building practical on-device intelligence remains challenging throughout the deployment lifecycle. Before deployment, models must remain accurate despite severe memory, computation, and energy budgets, and a single device often needs to support multiple sensing applications without deploying a separate model for each application. After deployment, the device continues to operate in changing real-world environments, where shifts in data distribution can degrade the model’s performance over time, so the model must be able to adapt to such shifts efficiently.

The first challenge …

Water-Heated Maisotsenko Cycle Humidifiers: A Component-Level Study On Evaporation And Exit Brine Concentration, Omar Abdulfattah Farag Omar A. Farag

Renewable Mechanical Energy

Maisotsenko-cycle (M-cycle) Heat-and-Mass Exchangers (HMXs) are usually assessed as part of complete cooling or desalination systems, which makes the behaviour of the humidifier itself difficult to distinguish. Here, a validated model is used to examine a water-heated M-cycle humidifier as an independent component. Inlet saline-water temperature, ambient temperature, Relative Humidity (RH), and water-to-air Mass-flow Ratio (MR) were varied, and performance was described by Water Evaporation Rate (WER), outlet-air specific humidity, and outlet brine salinity. Water heating and a larger MR produced the strongest increase in moisture addition because they maintained a warmer water film and greater transfer potential. At fixed …

Macroscopic Classical And Quantum Models Of Inverse Compton Scattering, Emerson Penn Rogers

Physics Theses & Dissertations

Inverse Compton sources — in which a relativistic electron beam scatters a laser pulse to produce tunable, collimated, high-energy radiation—have emerged as among the most promising compact radiation sources, with applications ranging from nuclear photonics to medical and nanoscale imaging and metrology. The most viable current tabletop configuration couples laser-wakefield acceleration with inverse Compton scattering, producing GeV-scale electron beams over millimeter distances. As laser intensities increase and electron energies grow, the interaction enters the radiation reaction regime, where the energy radiated by the electron becomes a significant fraction of its kinetic energy. Predicting the scattered electron energy spectrum — the …

Laponite Nanosilicate As A Platform For Antigen–Adjuvant Co-Delivery In Vaccination, Haoyu Qi

McKelvey School of Engineering Graduate Student Theses & Dissertations

Nanosilicates are two-dimensional, charged nanomaterials with tunable surface chemistry that enable electrostatic interactions with proteins and nucleic acids. These properties make Laponite nanosilicate a promising platform for vaccine delivery, where coordinated antigen–adjuvant presentation and lymph node delivery are important for shaping immune responses. This thesis investigated nanosilicates as scaffolds for lysozyme-based antigen delivery and co-delivery with CpG.

The preparation method reduced the apparent size of the NS–Lys–CpG complex at pH 10, although neutralization to pH 7 promoted larger aggregate formation. In vivo IVIS imaging after footpad injection showed persistent Cy7-associated fluorescence at the injection site for up to three weeks …

A Review Of The Safety Alert Systems In Commercial Vehicles: Implementation Challenges And Trends For Electronic Logic Devices And In-Cab Alerts, Md Sadman Islam, Deep Patel, Ahmed Sajid Hasan, Mohammad Jalayer, Abdul S. Ngereza, Emmanuel Kidando

Civil and Environmental Engineering Faculty Publications

The trucking industry is crucial to the US economy, accounting for 73.1% of the value, 71.1% of the cargo, and 42.0% of the ton-miles of all commodities transported nationwide. Despite its pivotal role, the industry is affected by high crash rates, with truck crashes resulting in 5,472 fatalities in 2023 alone. These incidents not only exhibit a higher fatality rate per vehicle mile compared with passenger cars but also cause substantial economic disruptions. Predominantly, these crashes are attributed to the failure to stop or slow down because of insufficient sight distances. In recent years, trucking companies have implemented various technologies, …

Structure Meets Context: A Simulation Study Of Centralized And Decentralized Decision-Making In Complex Environments, Murat Balci

Engineering Management & Systems Engineering Theses & Dissertations

The question of when to centralize or decentralize decision-making authority is a foundational problem in organizational theory and management science. Yet existing research often favors decentralized structures, frequently treating them as universally superior, and provides limited guidance on when centralization may be more effective. Leaning toward decentralization without thoroughly exploring options leaves organizational designers without clear direction under varying environmental conditions. This study addresses that gap by developing and applying a simulation-based framework to evaluate the context-dependent effectiveness of centralized and decentralized decision-making structures.

Drawing on contingency theory and decision science, the study conceptualizes environmental complexity along two dimensions: dynamism …

Understanding The Correlation Between Prediction Performance And Trust In Ai Through Scenario-Based Tasks, Likhitha Kammara

Theses and Dissertations

Trust in artificial intelligence is commonly assessed through self-reported scales or behavioral reliance, yet behavioral reliance is retrospective and can only be observed after a decision has already been made. This thesis examines whether prediction accuracy — a user's ability to predict what an AI system will recommend before its output is revealed — can serve as a prospective correlate of trust in the same empirical sense as behavioral reliance. The study was conducted in two phases using scenario-based AI decision tasks across disaster response, healthcare, and infrastructure restoration contexts, employing a between-group design in which participants either predicted AI …

Functionalized Loblolly Pine Derived Ultraporous Activated Hydrochars For Efficient Carbon Capture, Swarna Saha

Theses and Dissertations

The increasing concentration of anthropogenic carbon dioxide (CO₂) emissions has intensified the demand for efficient and sustainable carbon capture technologies. This dissertation investigates the development of functionalized ultraporous activated hydrochars derived from loblolly pine through hydrothermal carbonization (HTC) followed by chemical activation for enhanced CO₂ capture applications. Different functionalization strategies, including deep eutectic solvent (DES) modification, zeolite-assisted HTC, palladium-assisted HTC, and CO₂-assisted HTC, were systematically explored to evaluate the influence of pore structure, surface chemistry, and adsorption energetics on CO₂ capture performance. The synthesized materials were characterized using BET, FTIR, XRD, TGA, SEM, and adsorption isotherm modeling to establish the …

Field Calibration Of Flow Over Tilting Weirs In Canals, Joseph E. Pugh, Timothy K. Gates, S. Karan Venayagamoorthy, Caner Kutlu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Tilting weirs are widely used to regulate water levels in open channel irrigation systems and can also provide flow measurement capability that helps optimize irrigation efficiency and ensure equitable water distribution. This case study demonstrates adaptation of lab-based tilting weir ratings to field settings, where flow behavior is more complex. We compile and analyze an extensive data set derived from independent studies of five structures within three canal systems, featuring both lined and unlined channels with discharge ranging from 0.35 to 15 m3/s (12 to 530 ft3/s). Results indicate that lab-based rating equations can be calibrated to account for site-specific …

A Transfer-Learning And Continuous Optimization-Based Framework For Predicting Heat Treatment-Dependent Mechanical Properties Of Ded-Processed Low-Alloy Steels, Atiqur Rahman, Sung Heng Wu, Ranjit Joy, Frank Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Directed energy deposition (DED) of low-alloy steels involves strongly coupled effects among alloy composition, solidification behavior, and post-deposition heat treatment, making mechanical property prediction difficult when target-domain data are limited. This study develops a transfer-learning and continuous optimization framework for predicting heat treatment-dependent yield strength (YS), ultimate tensile strength (UTS), hardness (HV), and as-solidified phase fractions of martensite, ferrite, and austenite in DED-processed low-alloy steels. A CALPHAD-based dataset was generated for 125 low-alloy steel compositions. A multilayer perceptron (MLP) surrogate was first trained as a baseline model, then fine-tuned through transfer learning and progressively updated as staged continuous optimization; the …

A Laboratory Investigation Of Energy Dissipators At Embankment Dams, Nathan L. Young

All Graduate Theses and Dissertations, Fall 2023 to Present

Dams play a critical role in protecting communities from flooding and providing reliable water supplies. When large amounts of water pass through a dam’s spillway during floods, the discharge can travel at high speeds and carry potentially destructive kinetic energy that can damage the dam or erode downstream channels if that energy is not properly controlled. To reduce this risk, engineers commonly use hydraulic structures called energy dissipators that slow spillway discharge and safely release it downstream.

Commonly used energy dissipators at embankment dams include stilling basins that rely on a hydraulic jump – a sudden rise in water depth …

Nanostructured Negative Electron Affinity Gallium Arsenide Photocathodes With Enhanced Quantum Efficiency And Extended Charge Lifetime For Advanced Photoinjectors, Md Aziz Ar Rahman

Physics Theses & Dissertations

This dissertation presents a comprehensive experimental and computational investigation of nanostructured negative electron affinity (NEA) gallium arsenide (GaAs) photocathodes. This work was undertaken to achieve higher quantum efficiency (QE) and longer charge lifetime than conventional flat NEA GaAs electron sources commonly used in photoinjectors. Finite-Difference Time-Domain and charge-transport simulations of three types of nanostructure geometries reveal substantial QE enhancement over flat GaAs via Mie resonance mode excitation. Consequently, the truncated nanocone array (TNCA) photocathodes with heights of 400, 700, and 1000 nm were fabricated and NEA activated via Cs-NF₃ deposition. In a low-voltage ultra-high vacuum chamber with a base pressure …

Experimental Investigation Of The Discharge Modes Of Nanosecond Pulsed Plasmas At Atmospheric Pressure, Md Ziaur Rahman

Electrical & Computer Engineering Theses & Dissertations

The generation of repeatable and stable nanosecond pulsed atmospheric pressure plasmas is important to non-thermal plasma applications in various fields including medicine, material processing, food processing, and plasma ignition for combustion. This dissertation investigates the atmospheric pressure plasma initiation and formation under 10 – 200 ns pulsed power for electrode configurations applicable for transient plasma ignition (TPI) for combustion. The impacts of pulsed power parameters, gas condition, and electrode geometry on the discharge initiation and modes (i.e., streamer, transient spark and spark) are systematically evaluated for applying TPI for combustion. We evaluated the discharge modes driven by both longer and …

Decarbonizing The C3 Splitter: Performance Optimization And Environmental Impact Of Mvr Integration, Dalia A. Ali Associate Prof.

Chemical Engineering

Due to the relatively low volatility (α) of propane and propene components, their separation is one of the most energy-intensive processes in the petrochemical industry. This study evaluates the technical, environmental and thermodynamic performance of a mechanical vapor recompression (MVR) heat pump integrated into a C3 splitter, compared to a conventional steam-heated distillation column. A sensitivity study was conducted using Aspen Plus software at different pressures, reflux ratios (RR) and at turndown operations. According to the results, the MVR system uses a compressor to raise the overhead vapor pressure to 38.7 bar to operate the heater without the need for …

A Verification And Validation Framework For Model-Based Systems Engineering Using Executable Architecture Models And Integrated Simulation, Michael O. Cruz

Open Access Theses & Dissertations

Model-Based Systems Engineering (MBSE) reaches its full value when architecture does more than describe a system. It should help engineers carry stakeholder need and system intent into executable analysis, preserve the configuration and criteria used, and return evidence that can be reviewed in the same architecture context. This dissertation develops and evaluates a seven phase, architecture-driven verification and validation framework for that purpose. The framework defines the responsibilities that connect SysML architecture, controlled execution, domain simulation, configuration management, persistent data, analytics, and accountable engineering review. A reusable Cameo/SysML digital test environment plugin provides the reference implementation for orchestration and model …