Engineering Commons^™

Two-Photon Imaging For Characterizing Tumor Microenvironmental Changes In Non-Small Cell Lung Cancer Associated With Metastatic Recurrence, Paola Monterroso Diaz

Graduate Theses and Dissertations

Lung cancer remains the leading cause of cancer deaths, comprising nearly 25% of all cancer deaths (Sung et al., 2021a). The five-year survival rate of patients with non-small cell lung carcinoma (NSCLC) remains significantly low given that over half present with locally advanced or metastatic disease at time of diagnosis, and experience tumor recurrence following therapeutic intervention (Tamura et al., 2015; Uramoto & Tanaka, 2014). Current evaluation techniques to assess treatment response are lacking, given they are implemented several weeks after treatment completion and are solely based on anatomical changes in tumor size, forgoing other criteria such as functional or …

Causal Discovery In Time Series Data Using Deep Learning Techniques, Saima Zahin Farhana Absar

Graduate Theses and Dissertations

Causal structure learning from observational data has been an active field of research over the past decades. In the literature, different algorithms and models have been proposed, such as constrained-based methods and score-based methods including the emerging deep learning-based methods. However, most of the approaches apply to static and non-dynamic data only. In many applications, the data is temporal. For example, monitoring systems, weather surveillance systems, and stock data, to name but a few. Incorporating temporal information is an important extension of the causal discovery field. With the growth of observational data these days, the discovery of causal relationships from …

Investigation Of Conductive Die-Top Thermal Capacitors During Short Circuit Operation Of Silicon Carbide Devices, Youssef Abotaleb

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Silicon carbide (SiC) power devices have garnered significant attention in recent years due to their superior thermal and electrical properties compared to traditional silicon devices. However, SiC power devices suffer from severe reliability issues arising from their mechanical properties. This is because the Young's modulus of SiC is about three times larger than that of silicon, which correspondingly raises the mechanical stresses acting on the bonding structure, often leading to device failure under power shock events.

Traditional packaging materials and designs tend to constrain SiC performance, as hot-spot temperature resulting from a power shock is one of the key factors …

Identifying Challenges Faced By Small And Medium Enterprises (Smes) In The Middle East And North Africa (Mena) Region Through Total Quality Management, Mohamad Atef

Theses and Dissertations

Recently, Small and Medium Enterprises (SMEs) have become recognized as an important driver of global economic growth and innovation. This phenomenon is particularly evident in the MENA region, where small and medium-sized enterprises (SMEs) make a significant contribution to the businesses. SMEs offer significant benefits in terms of job creation, revenue generation, and fostering economic diversity. Although SMEs have a vital contribution in the economy of the MENA region, SMEs face many challenges that hinder their development and long-term viability. Focusing on these challenges is very important for fostering a vibrant and resilient economic environment. The objective of this thesis …

Learning To Represent Temporal Dynamics And Generative Factors For Intelligent Visual Navigation, Sahand Khoshdel

All Theses

Visual navigation systems are crucial in various applications, including autonomous driving, unmanned aerial systems (UAS), and industrial automation. For these systems to operate efficiently in dynamic environments, they must not only interpret complex surroundings but also anticipate changes over time. Temporal prediction—forecasting environmental changes like moving obstacles or shifting lighting conditions—enables navigation systems to act proactively, enhancing both safety and performance. This dissertation investigates representation learning methods both as a backbone feature extractor for RL agents as well as a proxy for systems oriented for Explainable AI (XAI). Two main projects are presented as case studies to achieve the aforementioned …

Using Nano-Ities For Detection Of Metal Ions In Complex Aqueous Solutions, Mohammed Muzammil Nishar Ahmed

Theses and Dissertations

Recent urbanization has induced a rapid increase in heavy metal exposure to humans. The exploitation of heavy metals for economic gains coupled with poor and economically infeasible recycling methods have led to poor management of heavy metal wastes, which has opened up several pathways for heavy metals to enter the human body. Such heavy metals target many vital organs, but the early symptoms are common and difficult to diagnose. Severe symptoms appear in later stages and are very expensive to treat and the damage caused to the health are not typically reversable in such later stages. To counter this issue, …

Learning-Based Feature Identification For Rendezvous And Capture Of Non-Cooperative Space Objects, Trupti Mahendrakar

Theses and Dissertations

In recent years, On-Orbit Servicing (OOS) and Active Debris Removal (ADR) have attracted increasing interest due to growing concerns about space debris. This debris poses a significant risk to spacecraft, as collisions can catastrophically end missions and potentially trigger a cascading chain reaction of more debris. Space debris ranges from tiny paint chips to large non-functional spacecraft and even launch vehicle components. One way to mitigate the formation of additional space debris is to reduce the total number of large non-cooperative resident space objects present in operational orbits. This can be achieved through two approaches: de-orbiting these objects as part …

Advancing Grid Modernization Through Data-Driven Resilience Modeling And Hosting Capacity Of Distributed Energy Resources, Oscar Samuel Acosta

Open Access Theses & Dissertations

This Ph.D. dissertation focuses on advancing the integration of distributed energy resources (DERs) through concepts surrounding their impacts on power system stability, resilience, and hosting capacity (HC). This dissertation addresses crucial topics in renewable energy deployment, transient fault response, and dynamic modeling. The work begins with the development of renewable energy source (RES) models tailored for offsetting residential heating, ventilation, and air conditioning~(HVAC) and commercial cooling loads. These models utilize solar photovoltaic (PV) and wind energy systems to produce scalable frameworks adapted across diverse climates and building types in application of a partial-load targeting methodology. The dissertation then transitions from …

Myofibroblast Targeted Liposomes For The Treatment Of Skin Fibrosis, Elfa Beaven

Open Access Theses & Dissertations

Continuous overactivation of myofibroblasts leads to excessive deposition of profibrotic proteins, which in turn causes tissue stiffness and, ultimately, organ failure. One of those proteins, Cadherin-11 (CDH11), is reported to be overexpressed in the tissue of fibrotic skin, specifically on myofibroblasts. Similarly, chronic inflammation drives fibrosis progression in autoimmune-related illnesses like systemic sclerosis (SSc). Therefore, it is hypothesized that CDH11 could be a target for cell-specific delivery of antifibrotic therapies to fibrotic skin tissue. Here, a CDH11 peptide conjugated liposome loaded with Tofacitinib, a JAK inhibitor, was developed to understand the potential of targeted therapies to treat skin fibrosis. The …

Developing A Bioengineered Nanoparticle For Improving Oral Absorption Of Iron Supplements., Mila Biswas

Open Access Theses & Dissertations

Iron deficiency (ID) and iron deficiency anemia (IDA) are widespread nutritional issues, affecting millions globally. Conventional iron supplements often suffer from low absorption rates and gastrointestinal side effects. We investigated β-glucan derivatives as potential carriers to enhance iron absorption and mitigate these drawbacks. This study explored a novel β-glucan-based carrier system loaded with ferrous sulfate heptahydrate. In-vitro studies demonstrated sustained iron stability for over six hours in simulated gastric fluids due to the carrier's affinity for stomach mucin. Particle size analysis and scanning electron microscopy (SEM) images confirmed this specific binding. Additionally, drug release studies revealed a pH-dependent release profile, …

Dynamic Optimization Of Directed Energy Deposition Build Conditions Using Real-Time Monitoring Via Closed-Loop Control, Callan Herberger

Open Access Theses & Dissertations

Directed Energy Deposition (DED) is an additive manufacturing process that is being rapidly adopted by industry and is well suited for the fabrication of complex components in various metal alloys. DED provides unique benefits such as design flexibility, the potential for in-situ alloying, and an open environment that allows for unobstructed monitoring within the build chamber. Despite these benefits, fully exploiting additive manufacturing's (AM) potential remains a complex task for designers. This dissertation presents a framework for controlling Directed Energy Deposition process variables through in-situ monitoring. An exploration into modifying AM build conditions through the development and implementation of a …

Uncovering The Light Network Load Performance Penalty Of The Network Link Outlier Factor (Nlof), Michelle Lara

Open Access Theses & Dissertations

This thesis evaluates the effectiveness of the Network Link Outlier Factor with Most Likely Link (NLOF: MLL) algorithm under varying network load conditions. Repeated simulation experiments using Mininet were conducted for four different network-wide load levels: 100 Mbps, 500 Mbps, 1 Gbps, and 5 Gbps. Using statistical inference, our experimental results indicate that NLOF: MLL is ineffective under light load conditions (i.e., 100Mbps load) due to the limited network flow data available for its learning process. This limitation highlights a key challenge in applying the algorithm to lightly loaded networks. A preliminary algorithm was proposed to address this light-load performance …

Fatigue Endurance Of Alsi10mg Post Hip Heat Treatment With High Duration Thermal Aging, William Venable Newcomb

Open Access Theses & Dissertations

AlSi10Mg is one of the cornerstones of additive manufacturing (AM), with its materialproperties and relatively low cost making it extremely popular as an AM metal choice, specifically using Laser Powder Bed Fusion (LPBF). Many publications have focused on this material, studying tensile strength, fatigue, heat treatments, and more. However, an area that requires further study is the effect of aging on the materials fatigue properties, with this study examining an industry standard heat treatment of Hot Isostatic Pressing (HIP). Using studies that have already been completed, AlSi10Mg was fatigue tested at near 100% UTS and 75% yield strength after HIP …

Monitoring Of Laser Soldering Process In Hybrid Additive Manufacturing, Alexander P. Pustinger

Open Access Theses & Dissertations

Additive manufacturing (AM) has been a maturing technology that has expanded over the course of the last decade in major advancements especially in accessibility, process monitoring, modeling, and stock material design. As its industry use is growing, the demand for added improvements such as multi-functionality increases, such as with a hybrid system that allows for modification of printed parts with different electrical components like the Foundry Multi-3D system. The system's purpose is to create AM parts with multifunctional electrical components with the vision to expand to other areas of interest in manufacturing such as ISAM. This work explores the use …

Computational Investigation Of Boundary-Layer Transition Mechanisms In A Blunt Cone, Arturo Rodriguez

Open Access Theses & Dissertations

In this study, we have performed two-dimensional steady-state hypersonic CFD and one-and-two-dimensional steady-state heat conduction numerical simulations. We are using them to guide and study hypersonic boundary-layer transition ground testing physical experiments to be performed at Holloman High-Speed Test Track. We use surface heat transfer and fluid flow spot signatures to identify fluid flow regimes using laminar and turbulent numerical simulation solvers to understand boundary-layer transition thermocouple temperatures and fluid flow-forming structures. We have also analyzed the fluid flow in the geometries to be inviscid. We passed the CFD solution into the boundary-layer Harris code developed by NASA to explore …

Intrinsic, Doped And Alloyed Gallium Oxide Films For Optoelectronics, Francelia Sanchez Escobar

Open Access Theses & Dissertations

Due to the impressive advancement of present technology and increasing energy consumption, there is increasing demand for energy-efficient multifunctional devices based on low-cost, eco-friendly material systems. Gallium oxide (Ga2O3) is an emerging semiconductor with potential for the next generation of power electronics and optoelectronic devices due to its ultra-wide bandgap of 4.8 eV and high theoretical breakdown voltage of 8 MV/cm among other intrinsic properties. Some of the possible applications of β-Ga2O3 include ultra-violet (UV) solar blind photodetectors, field effect transistors, solar cells, and chemical sensors. However, to utilize its full potential, understanding the mechanistic aspects of thin film growth …

Enhanced Redox Storage And Diverse Intercalation In Layered Metal Organic Frameworks With A Staggered Stacking Mode, Satya Prakash Suman

Open Access Theses & Dissertations

Two-dimensional metal organic frameworks (2D MOFs) with honeycomb-like porous sheets are of growing interest for applications in electrochemical energy storage and electrocatalysis. Notably, 2D MOFs that host their porous sheets in eclipsed or slipped-parallel stacking modes possess continuous one-dimensional pores (1D) and have been widely studied. In contrast, related 2D MOFs with a staggered stacking mode have reduced porosity, are relatively rare, and are largely unexplored for applications. Here we report 2-fold enhanced redox storage and intercalation of diverse ions in a staggered-stacked, nonporous 2D MOF over its eclipsed-stacked, porous counterpart. Interestingly, both MOFs, despite undergoing similar ligand-centered redox processes, …

Demonstrating Feasibility Of Ultrasound-Sensitive Microbubbles Delivery To Treat Disruptions In The Blood Brain Barrier Endothelium, Rubens Jourdain

Theses and Dissertations

Vascular cognitive impairment and dementia (VCID) is one of the main causes of dementia. VCID is caused by age and other genetic factors that lead to disruptions in the blood brain barrier (BBB) and allow blood components to enter the brain. The currently available treatments of VCID include opening the BBB with high-frequency-ultrasound to deliver drugs to the brain. However, this only treats the already developed disease. Consequently, we developed a new drug delivery system whose goal is to restore the brain capillary endothelial cells (BCEC) lining the blood vessel. The objective of this study was to demonstrate the feasibility …

Adsorption Of Harmful Algal Bloom Toxins Using Biochar, Cadianne Chambers

Theses and Dissertations

Harmful Algal Bloom (HAB) events involve the proliferation of microalgae which discharge lethal toxins into fresh and brackish water bodies due to anthropogenic and climatic activities. Common examples of HABs include causative organisms such as Cyanobacteria, Pyrodinium bahamense and more. These genera are known to release potent toxins including Microcystins, and Saxitoxins, respectively, which can seriously endanger human and marine health. Ingestion of these toxins can result in several health problems, such as nausea, vomiting, gastroenteritis, skin irritation, liver damage, paralysis, and respiratory arrest. The Great Lakes, Gulf of Maine, Florida’s coasts, Lake Erie, and Lake Okeechobee have all been …

Heterogeneous Collaborative Robotics: Multi-Robot Navigation In Dynamic Environments, Tyler Nicholas Raettig

Theses and Dissertations

Abstract: The challenges of multi-robot navigation in dynamic environments, focusing on uncertainties in obstacle complexities, partial observation, and the transition of policies from simulations to the real world. The proposed approach utilizes a deep reinforcement learning (DRL) framework enabling a Light Detection and Ranging (LiDAR)-equipped robot to communicate with a camera-equipped robot to achieve optimal paths despite their different sensors. The key contributions include the development of a cooperative architecture for information exchange between robots, a DRL-based framework for learning navigation policies, and a training mechanism based on dynamic randomization for enhanced real-world adaptability. Experimental validation using Gazebo simulations demonstrates …

Advancing Biofabrication Methodologies To Develop Biomimetic Tissue Scaffolds For Musculoskeletal Applications, Nashaita Yezdi Patrawalla

Theses and Dissertations

Musculoskeletal injuries impose a significant global burden, affecting millions and generating an economic toll exceeding $14 billion. Tissue engineering has gained traction as a promising strategy offering potential for functional restoration of damaged musculoskeletal tissues. This research aims to advance biofabrication techniques for generation of biomimetic tissue scaffolds, by optimizing scaffold design and modulating fabrication process parameters to generate scaffolds for musculoskeletal regeneration with application-specific tailored properties. In this realm, collagen-based biomaterials have been extensively investigated for tendon and ligamentous applications, and in combination with bioceramics incorporated into the collagen framework to produce composite scaffolds that better recapitulate the native …

Theoretical Advancements In Hawkes Processes And Their Practical Applications, Xi Zhang

Theses and Dissertations

Hawkes self-exciting point processes have been widely used in fields such as seismology, finance and social media analysis. Despite decades of research focusing on these processes, several key aspects remain under-explored. These include broadly applicable methods for model evaluation and selection, intuitive nonparametric inference approaches akin to kernel density estimation for probability density functions, and strategies to enhance the performance of generative point process models in predictive tasks. In this dissertation, first, we extend the time-rescaling theorem, which is traditionally limited to non-terminating processes with complete observations, to accommodate terminating processes and incomplete observations as well. This extension allows for …

Improving Robustness Of Learning-Based Approaches In Autonomous Systems And Engineering Education, Godwyll Aikins

Theses and Dissertations

This dissertation advances the development of robust learning-based approaches across two complementary domains: engineering education and autonomous systems. Through four studies, this research addresses critical challenges in preparing data-proficient engineers and developing reliable autonomous systems that can operate under uncertainty and incomplete information. The engineering education study examines how mechanical and aerospace engineering undergraduates conceptualize and develop data proficiency skills essential for modern engineering practice. Through interviews with 27 students, the research employs the How People Learn framework to analyze student perspectives on information literacy, data interpretation, and computational thinking. The findings inform pedagogical strategies for developing data proficiency in …

Breaking The Procrastination Barrier, Bianca Ebanks

Theses and Dissertations

Procrastination is a common barrier to productivity, impacting individuals' ability to achieve goals, especially in academic and professional settings. This study investigates a mixed-methods online intervention combining Behavioral Analysis (BA) principles with mindfulness exercises to reduce procrastination. The aim was to develop a human-centered, personalized intervention that utilizes behavioral reminders and mindfulness techniques to address procrastination in 43 participants. Participants' procrastination levels were assessed using the Irrational Procrastination Scale (IPS), and interventions were tailored based on individual procrastination tendencies. Reminders were sent via email or text, with timing adjusted to participants’ specific needs. The intervention also included mindfulness exercises designed …

Assessing General Propulsion Architectures For Fast Transit Times To Mars For Crewed Missions, Vivek Bhatt

Doctoral Dissertations and Master's Theses

As NASA and commercial contractors, such as SpaceX, continue to develop their programs with Artemis and Starship, respectively, it is becoming more and more apparent that the program developments are ultimately for finding a way to put humans onto Mars. However, when we approach the current timeline of going to Mars, it usually involves a 6-9 month one way trip. Due to this, human spaceflight to Mars becomes more dangerous as exposure to affects such as solar radiation, long exposure to low gravity fields, and isolation. These are some of the many hazards that come with interplanetary space travel for …

Designing A Robust Lab Scale Electrocoagulation Reactor For Removal Of Micro- And Nanoplastics From Drinking Water, Emmanuel Louis Aduhene

All Graduate Reports and Creative Projects, Fall 2023 to Present

The widespread occurrence of micro and nanoplastics in drinking water sources could cause serious public health issues. These plastics particles, products of industrial operations and weathering of larger plastics, can interact with other contaminants in the environment, leading to more severe environmental pollution. Present drinking water treatment technologies were designed to remove suspended colloids. However, due to the distinct chemical and physical properties of micro and nanoplastics from conventional colloids, it is challenging for traditional chemical coagulation/flocculation/sedimentation process to achieve satisfying removal performance. This report investigates a design of a lab-scale electrocoagulation reactor for the removal of nanoplastics from drinking …

3d Bioprinted Coaxial Tubule Optimization For Human Aortic Endothelial Cell Growth, Ilse Gabriela Perez Garcia

Theses and Dissertations

This paper introduces a research study of printing parameter optimization of extruded, cell-laden, 3D bioprinted coaxial tubules, as well as cell interaction observations. Optimization of printing parameters seeks to reduce variability of the tubules’ inner and outer diameters. The tubules were manufactured from a 0.4% Collagen I - 1.6% NaC6H7O6 (Sodium Alginate) bioink, that reaches gelation through interaction with a 3.2% CaCl2 (Calcium Chloride) solution. The bioinks were extruded through a dual syringe pump mechanism connected to a coaxial nozzle, which is mounted on an adapted 3D FDM (Fused Deposition …

A Multiple Mixed-Method Analysis On Empathy In First Year Engineering Education, Libby Flanagan

All Dissertations

This multiple mixed method analysis focuses on exploring how teaching empathy to first year engineering students interacts with their engineering identity and their personal definition of the role of an engineer. The participants received a four-lesson series on empathy and engineering in the Fall of 2023. They completed a pre- and post-survey as well as wrote five written reflections over the course of this semester. Analysis of the survey results found that composite empathy and engineering identity scores increased significantly over the course of this semester and that the increase in female composite engineering identity scores was significantly larger than …

Neural Operator And Physics-Informed Deep Learning Approaches For Inverse Design Of Composites And Manufacturing Processes, Minglei Lu

All Dissertations

In this dissertation, artificial intelligence (AI) models are designed and used to accelerate inverse design of composites and manufacturing processes. The critical bottlenecks in machine learning (ML) including data availability, data quality, model generalization and adaptation, interpretability, physical consistency, and the ’black box’ nature of models for the inverse design are addressed. And the proposed AI models are tested under different engineering scenarios. Firstly, a fast deep neural operator (DNO) structure was developed to significantly reduce training time. This model was tested in the context of additive manufacturing, a transformative industrial technology that allows for the creation of materials with …

Optimization Of Polymeric Micelles As A Delivery System For Crispr/Cas9 Ribonucleoprotein, Lucian Williams

All Dissertations

Clustered regularly interspaced short palindromic repeats (CRISPR) is an adaptive immune system in bacteria that has been harnessed to perform precise genetic modifications in mammalian cells. Among CRISPR-associated (Cas) proteins, Cas9 has emerged as a transformative tool in gene editing due to its simplicity, high specificity, and versatility compared to the other Cas proteins and gene-editing technologies. Despite its potential to cure genetic disorders, the clinical application of Cas9 has been hindered by challenges such as immunogenicity, off-target effects, and low delivery efficiency. To address these issues, this dissertation explores using polymeric nanoparticle systems to encapsulate and protect Cas9 and …