Engineering Commons^™

Neural Network Based Digital Twin For A Half-Bridge Llc Resonant Converter, Nicholas Green

Legacy Theses & Dissertations (2009 - 2024)

This paper introduces a Neural Network based approach for creating a Digital Twin of a Half-Bridge LLC Resonant Converter. By using a set of measured inputs, the Digital Twin system can characterize the component values, and hard to measure switch characteristics such as the Junction Temperature or Gate-Source Capacitance. This capability is useful for reliability or health applications, and may also be useful for adaptive control. A case study is done for the LLC Resonant converter designed around an operating point. Data sweeps around that operating point are simulated to form a dataset. An introduction to Neural Networks is given …

Multi-Task Learning For Hybrid Communication Waveforms: Exploring Model Enhancement Techniques And Establishing Task Relationships, Saksham Dewan

Legacy Theses & Dissertations (2009 - 2024)

Wireless communications have become ubiquitous, enabling seamless connectivity and driv- ing innovations across various domains. As we look to the future, visible light communication (VLC) is a promising technology that offers the potential to revolutionize how we transmit and receive data. It seamlessly integrates multiple functionalities, including localization, control/sensing, and high-speed data transmission.This thesis proposes a multi-task learning deep convolutional neural network approach to optimize a hybrid waveform for VLC-enabled networks. By integrating Beacon Posi- tion Modulation (BPM), Beacon Phase Shift Keying (BPSK), and OFDM symbols within a virtual Pulse Width Modulation (PWM) envelope, this waveform supports localization, control/sensing, and …

Radio Frequency Interference (Rfi) Detection In Microwave Radiometry Using Multi-Dimensional Data Mining Techniques, Fathima Imara Mohamed Nazar

Legacy Theses & Dissertations (2009 - 2024)

Measurements of natural electromagnetic radiation from Earth using microwave radiometers provide deep insight into our planet and its environmental conditions. These insights are essential for quantifying, understanding, and predicting various geophysical processes, such as climate patterns, water cycles, carbon cycles, and more. These passive measurements are diverse and cover a wide range of frequencies, depending on the sensitivity of microwave radiation to changes in important geophysical parameters. However, it is important to note that the microwave spectrum is also utilized by active services, such as wireless communication networks and radars. As a result, Radio Frequency Interference (RFI) in the measurements …

Optimization And Fabrication Of Semiconductor Power Devices On 4h-Sic, Justin M. Lynch

Legacy Theses & Dissertations (2009 - 2024)

The work presented in this document focuses on the design, optimization, and fabrication of power devices on 4H-Silicon Carbide (SiC) substrates. Power devices convert or control electric power flow and are the main components of electronic power systems worldwide. Power electronic systems are used in both low-power and high power settings, including prevalent applications such as fast charging set-ups for personal electronic devices, electric vehicle motor drives, and renewable energy storage and grid connections. With a wide spread of applications and the further electrification of our society on the horizon, it is crucial to minimize the power loss of power …

Toward The Advancement Of High-Efficiency P-Type Doping In Iii-Nitrides: Novel Beryllium Doping Techniques, Benjamin Arthur Mcewen

Legacy Theses & Dissertations (2009 - 2024)

The III-nitride material system is well-suited to a broad range of applications in light emitting diodes and laser diodes, photodetectors, power management, and telecommunications. Much of III-nitrides’ utility derives from their direct, wide, and tunable bandgap, but it is their ability to be doped n- and p-type that makes them especially useful and attractive. However, despite the decades of academic interest and commercial success, p-type doping in III-nitrides is infamously difficult and inefficient. Magnesium, the only currently viable p-type dopant in III-nitrides, is not a shallow acceptor, and as a result, the activation efficiency of Mg in GaN is only …

Design And Fabrication Of Injectable Alginate Hydrogel Microstrands For Mesenchymal Stem Cell Delivery In Salivary Gland Tissue Regeneration, Sujith Chander Reddy Kollampally

Legacy Theses & Dissertations (2009 - 2024)

Fibrosis is a pathological wound healing process, driven by excessive accumulation of extracellular matrix (ECM) following tissue remodeling. Fibrosis occurs in diseased or damaged salivary glands caused by several conditions, such as Sjogren’s syndrome or radiation for head and neck cancers. Having better insight into the cellular and molecular progression of fibrosis will allow us to model new therapeutic approaches as fibrosis prevents salivary gland tissue regeneration and function. Pharmacological, tissue engineering and cell-based regeneration strategies have been widely explored to restore lost salivary gland function. Among cell-based therapies, exploitation of mesenchymal stromal/stem cells (MSC) for salivary gland regeneration has …

Flow Characterization With Acoustic Emission Sensing, Jackson Marsh

Mechanical Engineering Undergraduate Honors Theses

Acoustic emissions (AE) allow for non-intrusive sensing into many types of systems. In systems where there is flow of some type, AE is very useful as these types of systems can be characterized in many ways from the collisions or creation of the flow. Correctly setting up the AE system is extremely important. Failure to do so results in imprecision and inaccurate data being collected. Because of this synchronization techniques, sensor configurations, and data acquisition systems must all align. This can be done with off-the-shelf, commercial systems, but this does not allow for customization and the ability to tailor the …

Investigation Of Pra For Rapid Part Replacement, John Lazenby

Honors Theses

As the electronics industry transitions to using commercial-off-the-shelf (COTS) devices of increasingly smaller technologies, radiation effects analysis becomes more significant in mission planning. In this work a probabilistic risk assessment (PRA) program, RadSTATS, is used in the analysis of various COTS memories in a radiation environment. The probabilities that the bits in memory will be flipped due to single event upset (SEU) rates are calculated for each memory, volatile and non-volatile. The unavailability of bits was discovered to increase with increasing storage capacity. Methods of error detection and correction (EDAC) between the same manufacturer were seen to decrease at unavailability …

Recommendation System Using Machine Learning For Fertilizer Prediction, Durga Rajesh Bommireddy

Electronic Theses, Projects, and Dissertations

This project presents the development of a sophisticated machine-learning model aimed at enhancing agricultural productivity by predicting the optimal fertilizer suited to specific crop requirements. Leveraging a diverse set of features including soil color, pH levels, rainfall, temperature, and crop type, our model offers tailored recommendations to farmers. Three powerful algorithms, Support Vector Machines (SVM), Artificial Neural Networks (ANN), and XG-Boost, were implemented to facilitate the prediction process. Through comprehensive experimentation and evaluation, we assessed the performance of each algorithm in accurately predicting the best fertilizer for maximizing crop yield. The project not only contributes to the advancement of machine …

Quantifying The Role Of Karst Groundwater On Mountain River Discharge, Devon Hill

All Graduate Theses and Dissertations, Fall 2023 to Present

A primary objective of hydrological research is to anticipate the shifts in water supply due to climate change. These shifts are difficult to predict in karst areas like Logan Canyon because much of the water moves through large fractures and cave networks that transport groundwater quickly, but there are some groundwater fractions which move very slowly. Many studies in karst regions use spring dynamics to assess aquifer condition, but overlook other influences such as exchanges between a river and the underlying aquifer. In this study, we calculated the quantity and chemical makeup of these groundwater and surface water exchanges by …

Techniques To Overcome Energy Storage Limitations In Electric Vehicles, Matthew J. Hansen

All Graduate Theses and Dissertations, Fall 2023 to Present

Electric vehicles are becoming increasingly popular, battery limitations (cost, size, and weight) complicate electric vehicle adoption. While important research on battery development is ongoing, this dissertation discusses two main approaches to overcome those limitations within the existing battery technology paradigm. Those thrusts are: improving battery health through an optimal charging strategy and minimizing necessary battery size through dynamic wireless power transfer. In this dissertation, relevant literature is discussed, with opportunities for further development considered. Within the two thrusts, three objectives sharpen the focus of the research presented here. First, a planning tool is defined for a battery electric bus fleet. …

Tracking Perfluoroalkyl Substances From Wastewater Influent To Its Accumulation In Vegetables And Forage Grass, Simon Kozik

All Graduate Theses and Dissertations, Fall 2023 to Present

Per and poly-fluorinated alkyl substances (PFAS) are a class of chemicals that are persistent in the environment. PFAS was found in wastewater, which can be used after wastewater treatment for irrigation water, and in the biosolids that can be mixed with soils to provide nutrients and generally improve soil quality. This study found when wastewater was used it increases the level of PFAS in vegetables and forage grass. PFAS concentrations were tracked from the influent of the wastewater treatment plant to the effluent, to the irrigation water, to the soil, and finally into the vegetable and forage grass grown on …

Development And Testing Of An 8-Bit Digitally Throttled Hybrid Rocket Motor, Trevor W. Coombs

All Graduate Theses and Dissertations, Fall 2023 to Present

Hybrid rocket motors that use a solid fuel grain and liquid oxidizer are low-cost and safer alternatives to traditional rocket motors. Another benefit of hybrid rocket motors is that during a burn, the amount of oxidizer into the combustion chamber can be changed, this capability is called throttling. To take advantage of the throttling ability of hybrid rocket motors, a throttling valve made up of 8 individually controlled valves is designed, developed, and tested, which is documented in this thesis. The results of the testing campaign show that the 8-bit digital throttling valve technology is an effective throttling technology and …

Field Flow Measurements For Pipe Installations With Non-Ideal Conditions, Jake Douglas

All Graduate Theses and Dissertations, Fall 2023 to Present

Accurate flow measurement data is necessary to effectively manage water resources. The purpose of this research is to investigate options to improve field flow measurement by investigating alternatives for calibrating flow meters installed in non-ideal piping. Typically, to accurately measure a flow rate using most types of flow meters, it is recommended that a straight section of pipe be installed immediately upstream and downstream of the flow meter to avoid flow fluctuations at the meter location. However, in many cases, flow disturbances upstream of the meter are unavoidable.

The performance of field flow measurements in non-ideal piping scenarios were studied …

Water Data Science: Data Driven Techniques, Training, And Tools For Improved Management Of High Frequency Water Resources Data, Amber Spackman Jones

All Graduate Theses and Dissertations, Fall 2023 to Present

Electronic sensors can measure water and climate conditions at high frequency and generate large quantities of observed data. This work addresses data management challenges associated with the volume and complexity of high frequency water data. We developed techniques for automatically reviewing data, created materials for training water data managers, and explored existing and emerging technologies for sensor data management.

Data collected by sensors often include errors due to sensor failure or environmental conditions that need to be removed, labeled, or corrected before the data can be used for analysis. Manual review and correction of these data can be tedious and …

Understanding Peer Interactions In Undergraduate Engineering Education, Jack C. Elliott

All Graduate Theses and Dissertations, Fall 2023 to Present

Whether they occur inside or outside the classroom, social interactions between undergraduate students play a key role in student success. As a result, engineering education researchers have sought to understand why students interact with certain peers, and which types of interactions relate to positive student outcomes. While existing studies show promising results for formal group assignments, most have been conducted in a single undergraduate course. Because important student interactions occur outside and inside courses, more research is needed to fully understand (a) why students choose to, or not to, interact with other students, and (b) how these interactions relate to …

The Importance Of Data Preparation In A Data Science Problem, Sophia Beard

Data Science Undergraduate Honors Theses

This study is going to be based on an inventory outlier automation data science problem that is being solved to identify and prescribe inventory level outliers to help keep shelves stocked in terms of beverages. The objective of this paper will address why it is so important to understand the data that is involved in a particular data science problem and how planning ahead ensures a successful outcome in the data science world. In this data science project, Spatiotemporal Outlier Analysis for Inventory Intervention Automation, it was crucial for the team to understand, research, and visualize the data we were …

Engineering Sustainable Bridge Deck Rehabilitation: Evaluating Mechanical And Electro-Chemical Properties Of Rapid-Set Patching Materials And Their Influence On Repair Durability, James Roberts

All Theses

As the state of the US infrastructure continues to deteriorate over time, a prominent issue especially in the field of reinforced concrete structures has been the ability to properly rehabilitate and extend the design service life of these structures. A majority of our existing reinforced concrete bridges were built in the construction boom during the 60’s, 70’s and 80’s, and were originally designed with a service life of approximately 50 years, thus showing that many structures are close to or have already exceeded their intended service life. Additionally, with a poor history of government infrastructure funding, it is seen to …

Application Of An Information Gain Model In A Motor Learning Task: An Application In A Laparoscopic Surgical Skills Task, Matthew Ball

All Theses

Psychomotor skills are comprised of physical movements and mental adaptations of movements to complete a task, generally using complex tools or components. Laparoscopic surgery training tasks are a prime example of tasks requiring psychomotor skills due to their demand for both fine hand movements and constant mental adaptation to the changing environment of the human body. A typical evaluation of these skills can be accomplished using learning curves, a graphical representation of skill growth in which a performance metric is plotted over a time experience metric. Previously, in the literature, several learning curves have been generated from the performance within …

Efficacy Of Virtual Reality-Based Simulations In Training Aviation Maintenance Technicians On Maintenance Procedures, Gayatri Anoop

All Theses

The COVID-19 pandemic forced institutions of higher education (IHEs) to halt in-person classes and transition to online platforms. Given the intricate process of adapting hands-on experiments to the online environment, this transition seemed particularly challenging for Science, Technology, Engineering, Mathematics, and Medicine (STEMM) labs. The abrupt nature of this transition added to the difficulties, given that the IHEs were inadequately prepared for seamless continuity during the pandemic. In the first phase of this project, a literature review was conducted to understand the impact of COVID-19 pandemic on education. Specifically, the review explored the challenges that institutions of higher education faced, …

Investigation Of Domain Formation During Phase Separation In A Mixture Of Flexible And Rigid Biopolymers, Steven Huntley

All Theses

Complex fluids and heterogenous mixtures composed of multiple types of polymers are found throughout industrial and biological fluid systems. For example, extrusion based additive manufacturing systems pass dense mixtures of polymers through the extrusion heads to deposit composite polymeric materials. In cells, active and complex mixtures of biopolymers self-organize into assemblies that perform critical physiological functions.

Polymers in dense solutions undergo phase separation as a result of differences in physiochemical properties. A few examples of these properties include charge, structure, rigidity, and hydrophobicity. We observe the formation of polymer domains composed of rigid and a flexible biopolymer species that phase …

Elucidating The Impact Of Casting Solvent On Vanadium Ion Transport In Solution-Cast Ionomer Biocomposites Containing Lignin, Zhongyu Wang

All Theses

This paper attempts to investigate the influence of solvent choice to the Nafion-lignin proton exchange membranes that used in the vanadium redox flow batteries. The influence of two different solvents: DMF and DMSO were investigated in this paper. Results show that when using DMSO as solvent, Nafion-lignin membranes' vanadium ion cross over can be greatly reduced in comparing with membranes prepared from DMF. Also, membranes prepared from DMSO also show higher water uptake ability and lower ion exchange capacity than the membranes prepared from DMF. This paper has also investigated the influence of lignin type to the membranes. Results show …

Analyzing An In-Line Compression Management System For Improved Performance In A High-Performance Computing Environment, Steven Platt

All Theses

High-performance computing (HPC) has enabled advancements in computation speed and resource cost by utilizing all available server resources and using parallelization for speedup. This computation scheme encourages simulation model development, massive data collection, and AI computation models, all of which store and compute on massive amounts of data. Data compression has enhanced the performance of storing and transferring this HPC application data to enable acceleration, but the benefits of data compression can also be transferred to the active allocated memory used by the application. In-line compression is a compression method that keeps the application memory compressed in allocated memory, decompressing …

Digital Twin In Military Ground Vehicles: Design And Predictive Maintenance, Conner W. Eddy

All Theses

Digital twin technology builds upon virtual engineering models, computer simulation, and real-time field data streaming to enable next-generation designs and predictive maintenance. A digital twin is a computer-based high-fidelity collection of models that predicts the performance of dynamic systems per operating cycles, input feature parameters, and data communication from a physical plant. Product Lifecycle Management (PLM) is growing in importance and is central to virtual design processes where the digital twin toolset fits into this emerging architecture. The product design process can be advanced using digital twin resources by eliminating the need for, and cost from, continual physical prototyping, reliability …

Evaluation And Development Of Tourniquet Test Methods, Catherine Pitts

All Theses

Since the beginning of the 21^st century the general perspective on tourniquets has changed to a more positive outlook on their life saving abilities. The US has seen a greater number of mass casualty events, and conflicts across the globe have led to an increased use of tourniquets. The increased demand has also led to faulty counterfeit tourniquets and improvised tourniquets that don not properly occlude blood flow or cause significant nerve damage to the injured limb.

ASTM started designing a tourniquet testing standard with experts in the tourniquet community to cut down on the dangers of tourniquet use. …

Modeling Of Multi-Period Disaster Logistics Planning In The State Of South Carolina, Emma Simon

All Theses

South Carolina is one of the most vulnerable states in the United States to the impact of hurricanes. Currently, when threatened with a natural disaster such as a hurricane, the state government makes many vital decisions based on knowledge and experience. In this study, the distribution of disaster relief commodities to meet immediate needs is analyzed through two models for the case of South Carolina to generate an optimal logistics strategy that considers the social vulnerability of affected populations. The first model is a multi-objective pre-disaster logistics model that uses a four-index formulation for the multiple trip vehicle routing problem. …

Sulfonated Lignin-Based Ionomer Biocomposite Membranes For Redox Flow Batteries, Aiswarya Mechoor

All Theses

The current benchmark membrane for vanadium redox flow batteries (VRFBs), Nafion™, accounts for up to 40% of the cost of the battery and suffers from poor ion selectivity, leading to diminished battery performance. Consequently, alternative ionomer membranes, such as sulfonated poly(ether ether ketone) (SPEEK), have recently garnered attention due to their lower cost and similar performance properties to Nafion. However, like Nafion, SPEEK also suffers from poor ion selectivity. In this study, we attempt to address the issue of poor ion selectivity by developing SPEEK–lignin composite membranes containing fractionated and functionalized lignin. Specifically, two lignin fractions – a low molecular …

Improved Ballistic Impact Resistance Of Nanofibrillar Cellulose Films With Discontinuous Fibrous Bouligand Architecture, Colby Caviness

All Theses

Natural protective materials offer unparalleled solutions for impact-resistant material designs that are simultaneously lightweight, strong, and tough. Particularly, the dactyl club of mantis shrimp features chitin nanofibrils organized in a Bouligand structure, which has been shown to effectively dissipate high-impact energy during powerful strikes. The mollusk shells also achieve excellent mechanical strength, toughness, and impact resistance with a staggered, layer-by-layer structure. Previous studies have shown that hybrid designs, by combining different bioinspired microstructures, can lead to enhanced mechanical strength and energy dissipation capabilities. Nevertheless, it remains unknown whether combining Bouligand and staggered structures in nanofibrillar cellulose (NFC) films, forming a …

Evaluating Company Culture Of Roofing Contracting Companies To Attract And Retain Women In The Industry, Gopika Viswanathan

All Theses

The US construction industry, similar to many other industries, has a low representation of women. This difference is even more pronounced in construction trades, such as the roofing industry. The admission of more women into the industry is important to address workforce shortage issues that the industry is facing. Company culture has been cited as one of the primary reasons why women choose not to enter the industry or face barriers during their careers. The main objective of this study was to evaluate the company culture of roofing companies through factors identified by literature and by women and companies in …

Depression And Anxiety: Investigating The Impacts Of Scheduling On The Mental Health Of Healthcare Workers During The Covid-19 Pandemic, Christofer Gonzaga

All Theses

Depression is a growing problem in the United States and has ballooned into a globally recognized mental health issue that affects shift workers in various fields (Lee et al., 2017). Rates of depression and anxiety have been shown to be substantially increasing and the COVID-19 pandemic amplified this prevalence of depression and anxiety. In the United States, the prevalence of depression symptoms was more than 3- fold higher during COVID-19 compared to before the pandemic (Ettman et al., 2020). The delivery of healthcare services is an ongoing and dynamic process, requiring clinicians to work in various shifts to ensure the …