Engineering Commons^™

N-Type Cdte Thin Films For Photovoltaic Applications, Wei Wang

USF Tampa Graduate Theses and Dissertations

Cadmium Telluride is widely used as a thin-film solar cell material due to its nearly ideal optical bandgap (~ 1.5eV) and its high absorption coefficient (> 104 cm-1). In the past several decades, most of the research focused on p-type CdTe solar cells. In recent years, the research on CdTe devices is mainly based on CdSexTe1-x (CST) absorbers, leading to substantial advancements in conversion efficiency, comparable to that of silicon-based solar cells. Presently, p-type polycrystalline CST/CdTe thin-film solar cells exhibit a notable efficiency of 23.1%. The state-of-art CST/CdTe solar cell has attained an almost optimal short-circuit current density (JSC) of …

Soc-Based Control System Performance Analysis For Trapped-Ion Quantum Computing, Tiamike Dudley

Electrical and Computer Engineering ETDs

Scatter-gather dynamic-memory-access (SG-DMA) is utilized in applications that require high bandwidth and low latency data transfers between memory and peripherals, where data blocks, described using buffer descriptors (BDs), are distributed throughout the memory system. The data transfer organization and requirements of a Trapped-Ion Quantum Computer (TIQC) possess characteristics similar to those targeted by SG-DMA. In particular, the ion qubits in a TIQC are manipulated by applying control sequences consisting primarily of modulated laser pulses. These optical pulses are defined by parameters that are (re)configured by the electrical control system. Variations in the operating environment and equipment make it necessary to …

Nonequilibrium Plasma Synthesis And Processing Of Iii-Nitride Materials, Dillon Patrick Moher

McKelvey School of Engineering Graduate Student Theses & Dissertations

Nitrogen is abundant on Earth as its diatomic form, and human activity has generated a significant demand for nitrogen-containing compounds. However, its triple bond energy of 941 kJ/mol makes it a poor reactive species in the ground state. Nitrogen-containing nonequilibrium plasmas are made up of background gas, electrons, ions, and a multitude of excited states of nitrogen or even atomic nitrogen. Many of these species have rather high reactivity. As such, the plasma medium is of great potential for driving chemical reactions that involve nitrogen as a reactant, i.e., nitrogen fixation into compounds like ammonia, high-energy-density polynitrogen compounds, and metal-nitride …

Nonequilibrium Plasma Synthesis And Processing Of Iii-Nitride Materials, Dillon Patrick Moher

McKelvey School of Engineering Graduate Student Theses & Dissertations

Nitrogen is abundant on Earth as its diatomic form, and human activity has generated a significant demand for nitrogen-containing compounds. However, its triple bond energy of 941 kJ/mol makes it a poor reactive species in the ground state. Nitrogen-containing nonequilibrium plasmas are made up of background gas, electrons, ions, and a multitude of excited states of nitrogen or even atomic nitrogen. Many of these species have rather high reactivity. As such, the plasma medium is of great potential for driving chemical reactions that involve nitrogen as a reactant, i.e., nitrogen fixation into compounds like ammonia, high-energy-density polynitrogen compounds, and metal-nitride …

Analysis Of The Impact Of Pavement Characteristics On Road Traffic Safety And Pavement Management Using Statistical Heterogeneity Models, Huiqing Lyu

USF Tampa Graduate Theses and Dissertations

Pavement shall accommodate current and predicted traffic needs in a safe, durable, and cost-effective manner. Among pavement surface characteristics, pavement friction is a critical factor contributing to roadway safety, as it directly impacts a driver's ability to execute steering, braking, and acceleration maneuvers safely. Ensuring an adequate level of pavement friction is essential to minimize the skidding risk for all road users. Continuous pavement friction measurement (CPFM) has recently become a proven approach, revolutionizing safety-related pavement management and skidding crash injury prevention. Meanwhile, pavement roughness has long been linked to vehicle fuel efficiency and pavement structural degradation. Perceptions of pavement …

Measuring And Modeling Grease Degradation, Alan Gurt

LSU Doctoral Dissertations

Lubricating grease is an ideal lubricant for many devices such as roller bearings, journal bearings, slide bearings, gears, and many types of joints due to its simplicity. Once grease is put in place, it can often provide adequate lubrication for extended periods of time without the need for a complex supply system that would generally be needed for oil lubrication. However, during prolonged use, various degradation mechanisms change the physical and chemical properties of grease, possibly leading to inadequate performance and machinery failure.

In order to succinctly quantify the degradation of grease, it is essential to have robust, meaningful test …

Development Of Machine Learning-Based Tool For Prediction Of Long-Term Field Performance Of Asphalt Concrete Overlays In A Hot And Humid Climate, Elise Mansour

LSU Doctoral Dissertations

The performance of pavement plays a critical role in Maintenance, Rehabilitation and Reconstruction (MR&R) for highway agencies. Reliable and accurate estimation of pavement performance can be instrumental in prioritization of the limited resources and funding for highway agencies. The latter requires robust prediction models that can handle large-scale, real-world data and can forecast pavement performance in the long run. Unfortunately, the traditional performance prediction models have raised concerns regarding their efficiency and accuracy. It is because these models were based on a limited number of explanatory variables, were not up-to-date and were designed for forecasting short-term (up to five years) …

Forensicllm: A Local Large Language Model For Digital Forensics, Binaya Sharma

LSU Master's Theses

Large Language Models (LLMs) excel in diverse natural language tasks but often lack specialization in fields like digital forensics. Their reliance on cloud-based APIs or high-performance computers restricts their use in resource-limited environments, and response hallucinations could compromise their applicability in forensic contexts. We introduce ForensicLLM, a 4-bit quantized LLaMA-3.1-8B model fine-tuned using Retrieval Augmented Fine-tuning (RAFT) on 6,739 Q&A samples extracted from 1,082 digital forensic research articles and curated digital artifacts. Evaluation on 2,244 Q&A samples showed that ForensicLLM outperformed the base LLaMA-3.1-8B model by 4.06%, 5.43%, and 15.79% on BERTScore F1, BGE-M3 cosine similarity, and G-Eval, respectively. Compared …

Techno-Economic Analysis Of Waste Plastic Gasification, Henrik Don-Yor Ketting

Master's Theses

The increasing generation of plastic waste and its environmental impact has driven interest in alternative disposal methods such as gasification. This study presents a techno-economic analysis of the gasification of waste plastics, specifically polypropylene (PP) and polyethylene (PE), to produce syngas. A two-stage process—thermal decomposition followed by steam reforming—was simulated using Aspen Plus. The simulation results were validated against experimental data available in the literature. The economic analysis was conducted by estimating the capital and operating costs of the gasification plant, considering factors such as feedstock costs, energy requirements, and syngas purification systems. Net Present Value Calculations were used to …

Float: A Multi-Scale Flood Loss Assessment Tool Developed From Experimentally Derived Material Damage, Anna Katya Opel

Doctoral Dissertations

Current practice of flood loss prediction presents limitations in accurately predicting building flood losses at multiple scales. While whole-building estimates can more accurately predict high-level losses (i.e., large groups of buildings), a significant analysis error is revealed with small-scale (i.e., individual, or small groups of buildings) investigation. The novel approach of collecting experimental flood data to support damage estimation has provided sufficient evidence that current damage models can and do under or overestimate loss. This research has developed a multi-scale approach to assessing flood losses based on experimentally derived material damage. The methodology is stored and accessible in a multi-scale …

Computational Design Of Complex Concentrated Alloys, Hamid Sharifi

Doctoral Dissertations

A high-throughput parameterization of modified embedded atom model (MEAM) interatomic potentials for combinations of Cu, Ti, Ni, Cr, Co, Al, Fe, and Mn was carried out using a genetic algorithm. Unary systems were parameterized based on DFT calculations and experimental results. MEAM potentials for 28 binary and 56 ternary combinations of the elements were parameterized to DFT results that were carried out with semi-automated frameworks. Specific attention was made to reproduce properties that impact compositional segregation, material strength, and mechanics. Utilizing the MEAM interatomic potentials and a Monte Carlo scheme, phase segregation in the CrNiCo, CuNiCr and CuNiCo fcc alloys …

Effectiveness Of Virtual Reality Training Environments, Lindsay Kristina Gouedy

Doctoral Dissertations

As technology has evolved so has training methodology in many applied fields. Training of aviation professionals is adapting by including technology features that allow for safer and less costly training methods. Pilot training is expensive given the number of flight hours and all that is included in the cost of flying an airplane. The main goal of this project is to assess the efficacy of the use of virtual reality environments as a valid training tool. Based on our literature review, we hypothesized that trainees perform simulated flight tasks more efficiently, with fewer errors, when trained using VR technology. The …

Experimental And Numerical Investigation Of Droplet Dynamics In Microscale Systems: The Influence Of Surfactants And Nanoparticles On Environmental Applications, Negin Bahadori

Master's Theses

Emulsions are suspensions of droplets dispersed into an immiscible liquid phase, with at least a water phase and an oil phase. The capability to incorporate both hydrophilic and hydrophobic components makes emulsions amenable to a variety of applications, such as bilgewater treatment and oil recovery. To optimize bilgewater treatment or oil recovery, many aspects must be considered, such as the effect of emulsion stability, the wetting conditions and, more in general, the possibility to characterize droplet’s behavior over static or dynamic conditions. This thesis investigates the roles of surfactants and nanoparticles in understanding droplet behavior in oil-water systems, with a …

Machine Learning-Driven Process Analysis And Optimization In Solid-State Welding And Fusion-Based Additive Manufacturing, Radif Uddin Ahmed

Master's Theses

In the modern era of advanced manufacturing, optimizing process parameters is pivotal in ensuring the quality and reliability of sophisticated component fabrication. This study presents a novel, data-driven approach to parameter optimization in two cutting-edge manufacturing techniques: Friction Stir Welding (FSW) and Laser Powder Bed Fusion (LPBF). By leveraging machine learning methodologies, this research addresses the critical challenge of efficiently determining optimal process parameters, a task traditionally relying on time-consuming and resource-intensive trial-and-error methods. This study will lead to a robust data-driven framework for process analysis of more advanced manufacturing techniques like the Additive Friction Stir Deposition (AFSD) process. Friction …

Effect Of Workload And Trust On Automation Levels In Human-Robot Collaboration, Abhiram Maddula

LSU Master's Theses

Automation is becoming increasingly common in manufacturing and assembly plants. The future lies in hybrid workspaces where the strengths of humans and robots complement each other, with robots excelling in precision, speed, and strength, and humans excelling in creativity, emotional intelligence, and complex decision-making. Collaborative robots can foster a more efficient and productive work environment by bridging the gap between human and machine capabilities. This study examines how semi-automated and automated modes impact human-robot collaboration, focusing on mental workload, trust, and task performance.

In this experiment, 58 participants performed a primary task alongside a collaborative robot assembling a miniature lamppost …

Robotic Multi-Object Grasping From A Pile: Techniques And Algorithms For Enhanced Dexterity, Tianze Chen

USF Tampa Graduate Theses and Dissertations

As robots become increasingly integrated into real-world applications such as warehousing, fulfillment centers, and manufacturing, the need for efficient and adaptable robotic systems grows. One of the key challenges is enabling robots to grasp multiple objects simultaneously, as this significantly boosts the efficiency of tasks like batch picking, sorting, and object transferring, reducing both time and energy consumption. This dissertation presents a comprehensive multi-object grasping (MOG) pipeline that includes pre-grasp selection, end-pose selection, grasping synergy calculation, and a data-driven model for estimating the number of objects being grasped. Central to this work is the development of the Experience Forest structure, …

Performance Optimization And Application Of P-Type Transparent Semiconductors In The Cdte Solar Cells, Md Zahangir Alom

USF Tampa Graduate Theses and Dissertations

CdTe thin-film solar cells are one of the major interests in the solar industry for their favorable properties. For example, CdTe has a near-ideal bandgap (1.45 eV) for absorption of the solar spectrum, and a high absorption coefficient ( ̴ 105 cm-1) and can capture 99% of light with only 2 µm of film thickness. Moreover, CdTe can be doped both n and p-type. Additionally, low production costs contribute to more affordable panel prices (0.40 $/W) [1]. The highest efficiency achieved to-date for this material is 23.1% demonstrated by First Solar, which is still lower than the theoretical limit [2]. …

Antimicrobial Activity And Photostability Of Cationic Conjugated Polyelectrolytes, Mohammed Ismael Khalil

Chemical and Biological Engineering ETDs

Antimicrobial resistance is a growing global health concern, driving the need for novel

therapeutic strategies. This study explores the antimicrobial efficacy of conjugated

polyelectrolytes (CPEs) and oligo-phenylene ethynylenes (OPEs) in bacterial and viral

inactivation. Quantitative analysis revealed that light-activated CPEs and OPEs

effectively reduced bacterial viability within minutes, with significant log reductions

observed under both light and dark conditions. Additionally, the antiviral potential of a

cationic conjugated oligomer was investigated, demonstrating rapid and near-complete

inactivation of SARS-CoV-2 under visible light, both in solution and on filter materials.

Further analysis of their photophysical properties revealed that, even after

photobleaching, the compounds …

Robust Data-Driven Run-To-Run Control Via One-Step Constrained Optimization For Automated Serial Sectioning, Rhianna M. Oakley

Mechanical Engineering ETDs

This Thesis develops a one-step predictive run-to-run controller (R2R-MPC) for automating a mechanical serial sectioning (MSS) system. MSS is a destructive material analysis process that iteratively removes slices of material and captures 2D images, reconstructing them into 3D representations. Commonly used in material science for characterizing materials and failure analysis, MSS typically operates in an open-loop fashion, which experiences high variability in material removal due to system disturbances. To address this, a robust closed-loop R2R-MPC is presented, modeling MSS process uncertainty using a linear differential inclusion identified from operational historical data. The R2R-MPC is posed as an optimization problem that …

Analyzing The Key Characteristics And Benefits Of Ccpr (Cold Central Plant Recycling) In Road Rehabilitation And Sustainability, Bassam Abou Yassine

Civil Engineering ETDs

Cold mix asphalt (CMA) technologies are being used in the United States and have environmental benefits. However, these technologies are not fully developed. We do not yet know their resilient and dynamic modulus, which are important for designing pavement thickness. They have not being used widely because we do not know also their performance. This study looks at three Cold Central Plant Recycling (CCPR) materials to help fill this gap. We conducted several lab tests, including the Hamburg Wheel Tracking Test (HWTT), Semi-Circular Bending Test (SCB), and Texas Overlay Test (TOT). We also tested the mechanical properties of the CCPR …

How Wildfires Threaten Water Resources: A Case Study Following The Largest Wildfire Recorded In New Mexico, Eric A. Joseph

Civil Engineering ETDs

Wildfire disturbance propagation along fluvial networks remains poorly understood. We use incident, atmospheric, and water-quality data from the largest wildfire in New Mexico’s history to quantify how this gigafire affected surface runoff processes and mobilized wildfire disturbances into fluvial networks after burning 1382 km². Surface runoff post-fire increased compared to pre-fire conditions, and precipitation events that are frequently observed in the affected watershed (<2-year recurrence) and fell during the post-fire first rainy season resulted in uncorrelated, less frequently observed runoff events (10-year recurrence). Wavelet coherence analysis highlighted that water quality disturbances propagated variably along the network, even at sites located >160 km downstream of the burn perimeter. Our findings emphasize the need to incorporate spatially resolved longitudinal sampling designs into wildfire water quality research and highlight the spatiotemporal co-dependency among atmospheric, terrestrial, aquatic processes …

Modeling W/V-Band Satellite Communications In The Presence Of Noise Jamming, Ryan Michael Eckman

Electrical and Computer Engineering ETDs

Understanding the performance of wideband modulated signals under noise jamming conditions is important for advancing W/V-band military satellite communications. This research developed and validated models to predict performance degradation of a communication channel in the presence of wideband noise jamming. Channel models were developed that included both modulated communication signals and jammer signals. Integrated models included environmental link factors and practical implementation factors. Integrated models were verified and validated using outdoor radio frequency environments utilizing two W/V-band transceivers, a portable W-band jammer, and software defined radios. Experimental results demonstrated excellent agreement with integrated model predictions. Channel degradation due to the …

Trust-Me: Resource Allocation And Server Selection Based On Trust In Multi-Access Edge Computing, Sean Tsikteris

Electrical and Computer Engineering ETDs

Multi-access Edge Computing (MEC) is crucial for Internet of Things (IoT) applications by optimizing data processing and reducing latency. This thesis presents contributions to resource allocation and decision-making in edge computing environments. The TRUST-ME model is introduced, involving multiple edge servers and IoT devices (users) offloading computing tasks to MEC servers. A utility function is designed to assess latency and cost benefits for IoT devices using server resources. The core innovation is a novel trust model that evaluates IoT devices’ confidence in MEC servers by integrating both direct and indirect trust, based on interactions and feedback from other devices. In …

Electrochemical Copper Printing For Wearable Electronics, Nirmita Roy

USF Tampa Graduate Theses and Dissertations

Wearable electronics have become a transformative force across industries like healthcare, aerospace, and military applications. However, a significant challenge persists in directly integrating electronic circuits onto fabrics. Addressing this challenge, the aim of this research is to introduce a novel sequential manufacturing process. Initially, a fabric is coated with a customized ink containing lignin, establishing a conductive template through laser burning. Subsequently, a localized Hydrogen Evolution Assisted (HEA) copper electroplating method is applied, resulting in a low-resistive circuit layout. Our investigations encompassed nanostructure analyses using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), Raman Spectroscopy, and Fourier Transform Infrared …

Investigating Spatiotemporal Trends Using Precursory Signatures: Implications To Develop Short-Term Earthquake Forecasting Techniques In Sumatra-Andaman Region, Ramya Jeyaraman J

Theses and Dissertations

Earthquake forecasting is a challenging field due to Earth's heterogeneous nature. This research aims to develop a short-term earthquake forecasting model by analyzing spatiotemporal trends and precursory signatures in the Sumatra-Andaman region, known for its high seismic activity and tsunami risk. The study adopts an interdisciplinary approach, integrating solid earth tides (SET), micro shocks, and outgoing longwave radiation (OLR) to gain deeper insights into seismic nucleation processes. The research begins by using Singular Spectral Analysis (SSA) to identify potential seismically vulnerable areas through the analysis of irregularities in SET.

A spatiotemporal analysis of micro shocks is conducted to assess the …

Cactus Infused Beads For Off-Flavor Mitigation In Aquaculture Systems, Rama Mahita Kambhampati

USF Tampa Graduate Theses and Dissertations

Aquaculture has become a vital component of global food production, now providing 50% of the world's fish supply. However, the industry encounters major challenges due to off-flavor compounds like Geosmin and 2-Methylisoborneol (MIB), which give fish an unpleasant earthy or musty smell. These compounds are detectable by humans at extremely low levels 0.7 parts per billion (ppb) for MIB and ten parts per trillion (ppt) for Geosmin—making them a persistent problem. Their presence not only reduces the sensory quality of aquaculture products but also results in significant economic losses, with U.S. catfish production incurring an additional $15–$23 million annually due …

Effect Of Specimen Size On The Tensile Properties Of Selective Laser Melted Ti-6ai-4v, Timothy L. Tan

Master's Theses

Metal additive manufacturing (MAM) is a burgeoning industry. It is capable of manufacturing metal components with fine, intricate features and enables localized microstructural control. Due to its fine resolution and compatibility with common engineering alloys, selective laser melting (SLM) is one particular MAM process popular in academia and industry. The biomedical and aerospace industries have shown exceptional interest in the capabilities of SLM with the alloy Ti-6Al-4V. Because SLM Ti-6Al-4V components are aimed for use in critical applications, it is necessary to understand how SLM processing characteristics affect final part performance. One characteristic of SLM Ti-6Al- 4V that requires further …

Enhancing Cross-Cultural Communication In Low-Resource Language Conversational Agents, Hardi V. Trivedi

Master's Theses

Recent advancements in natural language processing (NLP) and large language models (LLMs) have facilitated the development of systems capable of generating human-like responses across a wide range of tasks. However, the majority of research has focused predominantly on English, overlooking the vast linguistic diversity globally. For true global inclusivity, extending research to other languages is crucial, particularly as it can significantly benefit various sectors such as business, healthcare, government, and education. A major challenge in this expansion is the scarcity of digital data available and the limited number of pre-trained models for low-resource languages. Our research specifically addresses these challenges …

Longitudinal Pedestrian Safety Trends By Vehicle Type And Model: A 2015-2022 Study Of Texas, Olivia Tafoya

Civil Engineering ETDs

We observed pickup trucks, SUVs, and passenger cars and their two most popular vehicle models across Texas from 2015 through 2022. For each vehicle type and model, we obtained all reported pedestrian crashes, counts of registered vehicles, and vehicle design characteristics. Results suggest that older vehicles are more likely to seriously injure or kill a pedestrian than newer ones. They also indicate that SUVs were more deadly, after controlling for exposure using the number of registered vehicles, than other vehicle types. Of the models studied, the full-size SUVs proved to be particularly dangerous for pedestrians, being 2.08 times more likely …

A Novel Reinforcement Learning Method For Efficient Cross-Training Between Real And Simulated Robots, Zhonglin Liang

Master's Theses

Training reinforcement learning policy in a simulated environment can be a go-to choice for many research topics, as a simulated environment provides flexibility and costs less than building a physical environment for training. However, policy trained in a simulated environment often fails to transfer to the real environment for problems that have a more complex dynamics. As the solution, Sim2Real was proposed and it categorizes techniques that improve the performance of the transfer from simulation to reality. Sim2Real is an area of study that focuses on utilizing simulation data to train models that can apply to real world environment. It …