Engineering Commons^™

Globally Distributed Teams: The Between-Team Barriers That Impede The Successful Delivery Of Agile Software Development, Ben Park

Electronic Theses and Dissertations, 2020-2023

Software development projects fail far too often, costing companies billions in revenue, loss of the intended purpose and damage to both customers and suppliers in the process (A. Shenhar & V. Holzmann, 2017a). Understanding the challenge of ever-failing globally distributed software development projects is the goal and research conducted in this dissertation. The vision guiding the direction of this research is "What are the betweenteam barriers that impede the successful delivery of Agile software development in Globally Distributed Teams?" Through the literature review, a model was created and refined. A Mixed-Method Sequentially Replicated Case Study Research was performed to determine …

Variational Autoencoder And Sensor Fusion For Robust Myoelectric Controls, Keith A. Currier

Honors Undergraduate Theses

Myoelectric control schemes aim to utilize the surface electromyography (EMG) signals which are the electric potentials directly measured from skeletal muscles to control wearable robots such as exoskeletons and prostheses. The main challenge of myoelectric controls is to increase and preserve the signal quality by minimizing the effect of confounding factors such as muscle fatigue or electrode shift. Current research in myoelectric control schemes are developed to work in ideal laboratory conditions, but there is a persistent need to have these control schemes be more robust and work in real-world environments. Following the manifold hypothesis, complexity in the world can …

Modeling Individual Activity And Mobility Behavior And Assessing Ridesharing Impacts Using Emerging Data Sources, Jiechao Zhang

Electronic Theses and Dissertations, 2020-2023

Predicting individual mobility behavior is one of the major steps of transportation planning models. Accurate prediction of individual mobility behavior will be beneficial for transportation planning. Although previous studies have used different data sources to model individual mobility behaviors, they have several limitations such as the lack of complete mobility sequences and travel mode information, limiting our ability to accurately predict individual movements. In recent years, the emergence of GPS-based floating car data (FCD) and on-demand ride-hailing service platforms can provide innovative data sources to understand and model individual mobility behavior. Compared to the previously used data sources such as …

A Thermal, Mechanical, And Materials Framework For A Shape Memory Alloy Heat Engine For Thermal Management And Energy Recovery, Maria Chikhareva

Electronic Theses and Dissertations, 2020-2023

Shape memory alloy (SMA) heat engines possess an inherent property of sensing a change in temperature, performing work, and rejecting heat through the shape memory effect resulting from a temperature-induced phase transformation. This work presents a framework for the design and implementation of an SMA-based Stirling heat engine for maximum power or speed incorporating and combining mechanical, thermal, and material aspects. The motivation for this work comes from the growing need for reliable thermal management and energy recovery in both ground and space applications of interest to NASA and commercial space companies. In future lunar and Mars missions, an SMA …

Effect Of Particle Size On Mechanics Of Particle Reinforced Composites Using Photoluminescence Piezospectroscopy, Khanh Vo

Electronic Theses and Dissertations, 2020-2023

Nanoparticle reinforced composites are greatly desired by the aerospace community for a multitude of applications for their tailorable quasi-isotropic mechanical properties such as the high strength-to-weight ratio. With increasing demand of structural nanoparticulate composites, the optimization of their structural integrity and performance can be improved with a better understanding of the load transfer mechanics. Extensive nanoparticulate composites research has focused on the roles of particle shape, size, and volume fraction on the mechanical properties. Nanocomposites are often experimentally characterized through the determination of the bulk composite material properties. Load transfer research with a micro-mechanics perspective, distinguishing particle and matrix behavior, …

Machine Learning Applications In Advanced Additive Manufacturing: Process Modeling, Microstructure Analysis, And Defect Detection, Peter Warren

Electronic Theses and Dissertations, 2020-2023

Non-destructive evaluation (NDE) techniques are critical for assessing the integrity, health, and mechanical properties of materials manufactured from various methods. High fidelity NDE techniques are essential for quality control but often lead to massive data generation. Such a vast data load cannot be manually processed, this leads to a severe bottleneck for process engineers. Machine learning (ML) offers a solution to this problem by providing powerful and adaptable algorithms capable of learning patterns, identifying features, and finding hidden relationships in large sets of data. Various ML models are used in this work to improve predictions, improve measurements, detect anomalies, classify …

An Evaluation Of Thermocouple Reconstruction Techniques, Derek Brauneis

Electronic Theses and Dissertations, 2020-2023

Temperature measurements can be difficult to obtain across many different harsh environments such as engine combustion chambers, engine exhaust temperatures, and explosion fireballs. While there are alternate methods to measure fluid temperature such as laser measurements, acoustic measurements, and camera imaging techniques, these methods can often be expensive, difficult to implement, and not able to see within the environment. Thermocouples are popular sensors because they are cheap and easy to implement across a wide range of applications and can measure temperature in areas where other methods cannot reach or see. However, while these sensors are very popular and versatile, they …

Gait Strategies While Walking With Discrete Perturbations On A Self-Paced Treadmill, Cesar Castano

Electronic Theses and Dissertations, 2020-2023

Introducing perturbations on a self-paced treadmill allows participants to experience uncertain environments without restricting their ability to continuously change their walking speed and kinematics. In this dissertation, I evaluated how different self-paced treadmill controller sensitivities affected gait parameters and variability on decline, level, and incline slopes. I also investigated how healthy young and older adults adjust their gait strategies when responding to perturbations of varying unpredictability and whether the changes in gait strategies remained once the perturbations were no longer present. Lastly, I evaluated how differences in gait kinematics when responding to visual and mechanical perturbations at varying frequencies. I …

Micro-Credentialing With Fuzzy Content Matching: An Educational Data-Mining Approach, Paul Amoruso

Electronic Theses and Dissertations, 2020-2023

There is a growing need to assess and issue micro-credentials within STEM curricula. Although one approach is to insert a free-standing academic activity into the students learning and degree path, herein the development and mechanism of an alternative approach rooted in leveraging responses on digitized quiz-based assessments is developed. An online assessment and remediation protocol with accompanying Python-based toolset was developed to engage undergraduate tutors who identify and fill knowledge gaps of at-risk learners. Digitized assessments, personalized tutoring, and automated micro-credentialing scripts for Canvas LMS are used to issue skill-specific badges which motivate the learner incrementally, while increasing self-efficacy. This …

Developing Cost-Effective Specialty Adsorbents To Meet The Emerging Challenges Of Pollutant Removal In Surface Water Systems, Diana Ordonez

Electronic Theses and Dissertations, 2020-2023

The production of clean water is emphasized under the United Nations goals for sustainable development (SDGs), enlightening the acute need of developing new sustainable technologies in all disciplines. SDGs have urged all engineers in the 21st century to mitigate pollution of drinking water sources and prevent all receiving waterbodies from the impact of agriculture discharge, wastewater effluent, and stormwater runoff. Current water matrix constituents of concern include traditional pollutants (i.e., total nitrogen and total phosphate), natural organic matters (i.e., total organic carbon (TOC), tannic acid), heavy metals (i.e., copper, calcium), and harmful algae toxins (i.e., microcystin), as well as contaminants …

Auto-Ignition Characteristics Of Hydrogen Enriched Natural Gas For Gas Turbine Applications, Christopher T. Loving

Graduate Thesis and Dissertation 2023-2024

A successful transition to clean energy hinges on meeting the world's growing energy demand while reducing greenhouse gas emissions. Achieving this will require significant growth in electricity generation from clean and carbon-free energy sources. Several energy providers have already begun the transition from traditional carbon-based fuels to cleaner alternatives, such as hydrogen and hydrogen enriched natural gas. However, there are still many technical challenges that must be addressed when applying these fuels in gas turbines. The application of hydrogen or hydrogen/natural gas blends to advanced class gas turbines, which have higher operating pressures and temperatures has raised concerns about the …

Laser Powder Bed Fusion Of Bimetallic Structures, Asif Mahmud

Graduate Thesis and Dissertation 2023-2024

Laser powder bed fusion (LPBF) is a popular additive manufacturing (AM) technique that has demonstrated the capability to produce sophisticated engineering components. This work reports the crack-free fabrication of an SS316L/IN718 bimetallic structure via LPBF, along with compositional redistribution, phase transformations and microstructural development, and nanohardness variations. Constituent intermixing after LPBF was quantitatively estimated using thermo-kinetic coefficients of mass transport and compared with the diffusivity of Ni in the austenitic Fe-Ni system. The intermixing of primary solvents (Ni and Fe) in SS316L/IN718 bimetallic structures was observed for an intermixing zone of approximately 800 µm, and their intermixing coefficient was estimated …

Smart Mobility Sensing Of Origin-Destination Pairs Using Computer Vision, Seyed Sina Shid Moosavi

Electronic Theses and Dissertations, 2020-2023

The measurement of the origin-destination (OD) flow of individual passengers within the public transportation system plays a vital role in understanding resident mobility and facilitating route planning. Particularly in resource-limited communities, where access to advanced technologies like smart card systems may not be available, bus transportation systems play a crucial role in daily life. Traditional methods, such as driver logs, are not only time-consuming but also difficult to provide precise measurements of individualized OD pairs. Therefore, the primary objective of this study is to propose an automatic passenger sensing system (software) capable of accurately measuring OD pairs for individual passengers …

Structural Transformations In Photo-Thermo-Refractive Glass For Hologram Recording, Roberto Alejandro Alvarez Aguirre

Electronic Theses and Dissertations, 2020-2023

This dissertation focuses on the structural transformations in photo-thermo-refractive (PTR) glass that enable recording phase holograms for efficient transformation of optical beams and high resolution spectroscopy. PTR glass is a multicomponent silicate matrix doped with Ce, Ag, Sn and Sb. It is a holographic phase medium with the ability of permanent refractive index change after UV exposure and thermal development above 500°C due to the precipitation of a NaF crystalline phase. Electronic processes are studied by analyzing the structure of absorption and luminescence bands of PTR glass matrix and its dopants. We analyze the structural transformations in PTR glass from …

Development,Validation, And Integration Of Ai-Driven Computer Vision System And Digital-Twin System For Traffic Safety Dignostics, Ou Zheng

Electronic Theses and Dissertations, 2020-2023

The use of data and deep learning algorithms in transportation research have become increasingly popular in recent years. Many studies rely on real-world data. Collecting accurate traffic data is crucial for analyzing traffic safety. Still, traditional traffic data collection methods that rely on loop detectors and radar sensors are limited to collect macro-level data, and it may fail to monitor complex driver behaviors like lane changing and interactions between road users. With the development of new technologies like in-vehicle cameras, Unmanned Aerial Vehicle (UAV), and surveillance cameras, vehicle trajectory data can be collected from the recorded videos for more comprehensive …

Active Photonic Integrated Devices And Circuits On Thin-Film Lithium Niobate Platform, Ehsan Ordouie

Electronic Theses and Dissertations, 2020-2023

This thesis delves into innovative active photonic integrated devices and circuits on the thin-film lithium niobate (TFLN) platform, focusing on their applications and potential future advancements. We introduce a new family of electrooptic modulators (EOMs), the Four-Phase Electrooptic Modulators (FEOMs), which are fabricated using the TFLN platform. These devices effectively mitigate bandwidth and dynamic-range constraints in optical communication systems by reducing dispersion penalties and common-mode noises. Their functionality is demonstrated in a photonic time-stretch system. A dual-polarization variant further exemplifies the mitigation of both dispersion penalties and common-mode noises in long-haul communication links, marking significant strides towards the practical implementation …

Investigation Of Endothelial Mechanics On Primary Cell Functions: Endothelium Permeability And Wound Healing, Sean Beverung

Electronic Theses and Dissertations, 2020-2023

The endothelium composes the inner lining of blood vessels, the heart, and lymphatic vessels. Within the cardiovascular system, it is an extremely important structure, aiding in the regulation of blood pressure with the vascular tone, recruiting immune response, regulating the transfer of material in and out of the bloodstream, and the creation of new blood vessels through angiogenesis. The endothelium is composed entirely of endothelial cells. These cells lay in a flat squamous formation and are in direct contact with blood and aid in the regulation and transfer of material in and out of the bloodstream via active and passive …

Nanostructured Alloy Thin Film Fabrication And Application For Zinc-Air Battery And Lithium-Ion Battery, Guanzhi Wang

Electronic Theses and Dissertations, 2020-2023

The depletion of unsustainable fossil fuels and growing environmental issues have given rise to scientific challenges and research interests in the development of renewable energy technologies to meet the rising global energy demand. Electrochemical energy storage and conversion technologies (ESCTs), such as lithium-ion batteries, metal-air batteries, supercapacitors, and fuel cells, etc., offer a clean and sustainable strategy for utilizing energy. As the core components, the electrode materials, including anodes, cathodes, and catalysts, play a direct decisive role in the device's performance in practical application. Therefore, the development of high-performance and low-cost electrode materials is critical for the success of these …

Electroanalytical Investigations Of Microrna-Conjugated Cerium Oxide Based Nanomaterials For Biomedical Applications, Chaimae El Ghzaoui

Electronic Theses and Dissertations, 2020-2023

Diabetes patients are increasingly suffering from wound-healing impairments coupled with other severe medical conditions. High levels of oxidative stress and proinflammatory cytokines are predominant pathologic characteristics of diabetic wounds. Applying microRNA (miRNA) in gene therapy often successfully treats various disorders by generating highly specific bio-responses. Studies revealed that microRNA146a (miR146a), a regulator of inflammation, is downregulated in diabetic wounds. However, miR203 is found to be highly-expressed in diabetic foot ulcers in positive correlation with disease severity. We have synthesized Cerium oxide nanoparticles (CNPs) since they are used in various biomedical applications due to their high enzyme-mimetic activities and reactive oxygen …

Rotorcraft Lander Fixed To A Descending Capsule Backshell, Corey Zucker

Electronic Theses and Dissertations, 2020-2023

NASA is financing a mission to study the surface of Titan, Saturn's largest moon, to investigate the terrain, chemical compositions, and potential for existent life. This mission is an exciting advancement from Mars Ingenuity, because the quadrotor lander, Dragonfly, will be the first of its kind with four coaxial rotors. Upon entry into Titan, and at near surface atmospheric conditions, Dragonfly will exit a parachute supported backshell that has shed its protective heatshield. The aerodynamics of this state are significant in comprehending the dynamics of the overall system for successful deployment into powered flight. The studies presented here examine the …

Hypersonic Aero-Optic Measurements In A High-Pressure Shock Tube, Jonathan P. Mcgaunn

Graduate Thesis and Dissertation 2023-2024

The high-pressure shock tube facility (HiPER-STAR) at the University of Central Florida (UCF) is analyzed experimentally to demonstrate the practicality of hypersonic aero-optical testing in an impulse facility without the use of an expansion nozzle or acceleration tube. The investigation analyses driver gas blending with helium and hydrogen to raise the speed of sound ratio in an attempt to increase the Mach number for aero-optics testing. HiPER-STAR has a unique ability to withstand pressures up to 1000 atm and run in a double diaphragm configuration allowing for a significant pressure differential to be created between the driver and driven sections. …

Thermal Management Strategies For Hypersonic Flight: Supercritical Co2 Jet Impingement Cooling Investigation For Leading Edge, Manoj Prabakar Sargunaraj

Graduate Thesis and Dissertation 2023-2024

This study addresses the critical need for effective thermal management in hypersonic vehicles facing intense heat at their leading edge due to high enthalpy flow. The objective is to propose an active impingement cooling system that ensures the structural stability and performance of these vehicles. This dissertation presents an in-depth exploration of the numerical simulations conducted on the hypersonic leading edge, focusing on a 3mm radius with active cooling utilizing supercritical carbon dioxide (sCO2) as the coolant. The research incorporates conjugate simulations that merge external hypersonic flow and sCO2 active cooling. Utilizing a thermodynamic non-equilibrium two-temperature model and various chemical …

Heat Release And Flame Scale Effects On Turbulence Dynamics In Confined Premixed Flows, Max Fortin

Electronic Theses and Dissertations, 2020-2023

As industry transitions to a net-zero carbon future, turbulent premixed combustion will remain an integral process for power generating gas turbines and are also desired for aviation engines due to their ability to minimize pollutant emissions. However, accurately predicting the behavior of a turbulent reacting flow field remains a challenge. To better understand the dynamics of premixed reacting flows, this study experimentally investigates the evolution of turbulence in a high-speed bluff-body combustor. The combustor is operated across a range of equivalence ratios from 0.7-1 to quantify the role of heat release and flame scales on the evolution of turbulence as …

Design And Validation Of A Variable, Speed-Dependent Resistance Training Method For Muscle Hypertrophy, Alvaro Andres Aracena Alvial

Honors Undergraduate Theses

Muscle disorders and induced muscle atrophy impose critical risks to the well-being of an individual, limiting normal activities of daily living. Several resistance training methods have effectively reversed the progression of muscle atrophy. Weightlifting and hydrotherapy are the two widely practiced schemes for resistance training; however, there is the potential risk of excessive loads exerted on the muscles during weightlifting, and limited accessibility and cost are barriers to hydrotherapy. An alternative is using a resistance band. Some limitations include engaging multiple muscles/joints while only unidirectional resistance is feasible. To address these limitations, a VAriable Resistance Suit (VARS) was designed to …

A Numerical Analysis Of Shock Angles From Inward Turning Axisymmetric Flows, William L. Hilal

Honors Undergraduate Theses

Detonation-based propulsion systems are known for their high efficiency and energy release when compared to deflagrative systems, making them an ideal candidate in hypersonic propulsion applications. One such engine is the Oblique Detonation Wave (ODW) engine, which has a similar architecture to traditional scramjets but shortens the combustor and isolator to an anchored ODW after fuel injection.

Previous research has focused on using a two-dimensional wedge to induce an ODW while limiting total losses through the combustor. In this configuration, a two-dimensional wedge-based architecture entails a rectangular duct, limiting potential inlet design and increasing overall skin friction. However, an inward-turning …

Audible And Subaudible Components Of The First And Second Heart Sounds Using Phonocardiography And Seismocardiography, Daniella King

Honors Undergraduate Theses

Cardiovascular disease continues to be a leading cause of death in the United States, and a source of financial strain on the healthcare system. This prompts the need for new methods of low-cost, noninvasive technologies for cardiac monitoring to improve patient health and reduce healthcare costs. While the first and second heart sounds are common references that are listened to during auscultation of heart, seismocardiography (SCG) is a technology that detects chest sound vibrations with an accelerometer and may offer more information beyond the audible heart sounds. There is currently limited information regarding both the relationship between audible heart sounds …

An Optimization Study Of Small-Scale Propeller Blade, Fahad M. Nabid

Honors Undergraduate Theses

This research paper aims to investigate the optimization of smaller propeller blades to achieve maximum efficiency by studying the effect of the twist angle on reducing drag, increasing thrust, and preventing rapid wear on the blade. Inefficient propellers consume a significant amount of energy, particularly during low-speed flights. The low Reynolds number regime challenges aviation engineers to design propellers with the highest possible efficiency to minimize energy losses. The primary objective of this thesis is to optimize smaller propeller blade shapes to enable them to produce maximum efficiency. The advanced ratio of a propeller blade heavily influences the blade's performance …

Granular Jamming: Stiffness Vs Pressure And Organ Palpation Devices, Christopher H. Quach

Honors Undergraduate Theses

The intent of this thesis it to find a correlation between the stiffness of granular jammed particles and the pressure of the vacuum initiating the jamming force. Currently, granular jamming is being used to create palpation simulators for physicians to practice feeling the variety of stiffnesses of organs when healthy or ill. Because granular jamming allows for variable stiffness of any shape, it is an apt phenomenon to simulate the change of rigidity organs like the liver undergoes when diseased. For physicians to correctly identify how stiff the organ must be when using these palpation simulators, there needs to be …

Silver Doped Nanoceria (Agcnp) Integrated Silk Scaffold For Chronic Wound Healing, Architha K. Venkatesan

Honors Undergraduate Theses

Chronic wound healing can be seriously impeded by the formation of biofilms, infections, peri-wound edema, hematoma, osteomyelitis, and the formation of reactive oxidative species (ROS). We hypothesize that a scaffold created from Silver-Doped Nanoceria (AgCNP) embedding silk can be beneficial to aid the wound healing process, inhibit inflammation and prevent microorganisms from forming a biofilm over the wound. Current wound healing methods such as intradermal injections are not advantageous to use since they can cause unwanted responses elsewhere in the body other than the wound site. Silk, however, has a positive impact on the wound healing effect and can be …

Hypersonic Scramjet Inlet Development For Variable Mach Number Flows, Zachary P. White

Honors Undergraduate Theses

Hypersonic propulsion has become an increasingly important research field over the past fifty years, and subsequent interest in propulsion systems utilizing supersonic combustion has emerged. Air-breathing engines are desirable for such applications as hypersonic flight vehicles would not need to carry an oxidizer. Therefore, hypersonic air-breathing propulsion systems require an inlet with high mass capture and compressive efficiency. The present work seeks to outline the development and validation of a novel design tool for producing air inlet designs for hypersonic vehicles at variable flight conditions. A Busemann inlet was chosen for its high compressive efficiency, geometric flexibility, and existing experimental …