Engineering Commons^™

Simulation Of Fracture Strength Improvements Of A Human Proximal Femur Using Finite Element Analysis., Waleed Ebraheem Alim

Electronic Theses and Dissertations

The most common hip fracture in the elderly occurs as a result of a fall to the side with impact over the greater trochanter resulting in a fracture of the proximal femur. The fracture usually involves the femoral neck or the intertrochanteric region. It has recently been determined that the fracture crack of a hip fracture typically initiates on the superior-lateral cortex of the femoral neck and then propagates across the femoral neck, resulting in a complete fracture. The strength of the superior-lateral cortex of the femoral neck is likely determined by the combined properties of the generally thin cortex …

Improving Student Success And Engagement In Virtual And Hybrid Classrooms., Sydney Fogo

Electronic Theses and Dissertations

The following thesis examines virtual classes from the University of Louisville in the Fall 2020 semester to discover points of weakness relative to keeping students engaged in online courses. Three surveys were taken by a select group of participants over the course of the fall semester in order to collect student opinion on specific classes. Interviews were held with a subset of students from the group of participants and also with professors who taught the study’s participants in the fall of 2020. Their responses and conversations were used to determine possible areas of improvement for virtual classes. This information was …

Predicting Henry's Law Constants Of Volatile Organic Compounds Present In Bourbon Using Molecular Simulations., Christopher A Abney

Electronic Theses and Dissertations

Henry’s Law describes the partitioning of molecules into liquid and gas phases at low concentrations. Henry’s Law, which is based upon a species-dependent constant and the gas phase partial pressure, is useful for predicting phase behavior of dilute solutes. However, Henry’s Law constants are difficult to measure experimentally or to predict using structure-property or thermodynamic models. Herein, molecular simulations were used to calculate Henry’s Law constants for 18 volatile organic compounds (VOCs) present in bourbon. The novel simulations analyzed solvation thermodynamics of small organic molecules in 120 proof ethanol. A fast-growth non-equilibrium free energy method was used in which the …

An Investigation Of Barriers And Facilitators To Living Kidney Donation, Rachel E. Crenshaw

Electronic Theses and Dissertations

There is strong interest in increasing living kidney donation, as the need for kidney transplants is quite high. Although previous studies outline some barriers and facilitators associated with donating, living kidney donation comprises only a small percentage of overall kidney transplants and thus further research on factors influencing the decision to donate is needed to find ways to increase the donor pool. Ten semi-structured interviews of living kidney donors were completed and analyzed for common themes that either support the current literature or surface additional barriers and facilitators. In addition, a systematic review and analysis of social medial support groups …

Covid-19 Serological Diagnostic Development Using A Sars-Cov-2 Rbd Foldon Fusion, Joey Emery Breckenridge Jr.

Electronic Theses and Dissertations

Serological tests are conducted to assess humoral response against viral protein antigens, to assess viral exposure and protection from pathogens. The rapid development and modularity of serological assays have proven critical to managing the current SARS-CoV-2 pandemic. The receptor binding domain of SARS-CoV-2 is within the trimeric Spike protein and serves as a highly immunogenic target for potentially neutralizing antibodies. Current receptor binding domain serological assays use recombinant monomers or dimers of the receptor binding domain. The receptor binding domain is presented to the immune system natively in the context of the Spike protein trimer. Therefore, a recombinant trimeric receptor …

Cfd Analysis Of Acoustofluidic Channels And The Effects On Biologic Delivery., Zachary T. Long

Electronic Theses and Dissertations

T-cell transformation is an ever-expanding treatment for several types of cancer, with a potential to be adapted to other disorders in which the immune system plays a key role in the pathophysiology. Currently, all FDA approved chimeric antigen receptor (CAR) T-cell cancer therapies rely on transformation via viral transduction. However, viral transduction is plagued by poor consistency and the potential to create adverse immune reactions when T-cells are reintroduced into a patient. Other transformation methods are being explored, with an alternative called acoustofluidic sonoporation showing promise. In these procedures, cells are passed through a channel, of the millimeter scale, while …

Automated Conversion Of Multicellds Digital Cell Lines And Isa-Tab Filesets., Connor Joseph Burns

Electronic Theses and Dissertations

Biological simulation tools are a valuable asset to bridge the gap between biological experimentation and biological theory. As systems thinking has become more regularly applied to biological materials and processes, these materials and processes have been characterized in multi-disciplinary, computational manners. This characterization has yielded an ability to create more realistic simulation tools that can provide in silico experiments for a wider range of scenarios. One prominent simulation tool is PhysiCell, an open-source physics-based multicellular simulation program which utilizes input Digital Cell Lines or Digital Snapshots from the MultiCellular Data Standard (MCDS) project.

This project aims to allow data exchange …

Biomechanical Characterization Of Video-Recorded Short-Distance Falls Involving Children Equipped With A Biometric Device In A Childcare Setting: A Pilot Study., Danielle K. Cory

Electronic Theses and Dissertations

Background: A fall is the most common falsely reported injury scenario when a young child presents for medical care and the caregiver is concealing abuse. There is a lack of reliably witnessed falls with known outcomes to aid in the distinction between accidental and abusive injuries.

Objectives: The objectives of this study were to characterize video-recorded short distance falls involving young children in a childcare setting, to identify body regions most commonly impacted in these short distance falls, to characterize the head biomechanics of these falls, and describe fall characteristics. Additionally, physics-based models were used to predict fall biomechanics in …

Annealing Of Encapsulated Heavy Metals From Brine Water Utilizing Microwave Enabled Sol-Gel Process, Adam Michael Flynn

Electronic Theses and Dissertations

Various waste encapsulation strategies have been investigated to solidify and stabilize heavy metal wastewater for proper long-term storage. This work aims to enhance a method of novel sol-gel encapsulation of heavy metals from mock brine waters using tetramethyl orthosilicate with the addition of an annealing step at various temperatures in order to reduce leaching of metals from the silica monoliths when exposed to water. The metals tested for encapsulation and leaching were mercury (II) chloride, potassium dichromate, sodium selenite, boric acid, cadmium chloride, and copper (II) acetate. The annealing of the silica monoliths led to an increased degree of for …

Image Analysis Of Charged Bimodal Colloidal Systems In Microgravity., Adam J. Cecil

Electronic Theses and Dissertations

Colloids are suspensions of two or more phases and have been topics of research for advanced, tunable materials for decades. Stabilization of colloids is typically attributed to thermodynamic mechanisms; however, recent studies have identified transport or entropic mechanisms that can potentially stabilize a thermodynamically unstable colloidal system. In this study, suspensions of silsesquioxane microparticles and zirconia nanoparticles were dispersed in a nitric acid solution and allowed to aggregate for 8-12 days in microgravity aboard the International Space Station. The suspensions were subsequently imaged periodically at 2.5x magnification. Due to the inadequacy of existing image analysis programs, the python package “Colloidspy” …

The Impact Of Artificial Intelligence In The Customer Journey: A Case Study Of Bosch Usa And Defy South Africa, Tariro S. Munyengeterwa

Electronic Theses and Dissertations

Artificial intelligence (AI) continues to gain traction and is increasingly reshaping the media and marketing communications field. While significant research has been conducted on the impact of AI in other fields, there is little empirical evidence on how AI is affecting the customer journey. The present study explored both organizations’ current use of AI tools and how customer perceptions about AI affect AI usage and adoption through the lens of diffusion of innovation theory. The research was conducted using mixed-method qualitative research. In-depth interviews and a case study content analysis were conducted to collect and analyze the data. The results …

Understanding And Avoiding Ai Failures: A Practical Guide., Robert Max C Williams

Electronic Theses and Dissertations

As AI technologies increase in capability and ubiquity, AI accidents are becoming more common. Based on normal accident theory, high reliability theory, and open systems theory, we create a framework for understanding the risks associated with AI applications. In addition, we also use AI safety principles to quantify the unique risks of increased intelligence and human-like qualities in AI. Together, these two fields give a more complete picture of the risks of contemporary AI. By focusing on system properties near accidents instead of seeking a root cause of accidents, we identify where attention should be paid to safety for current …

Level Of Acceptance (Loa) For Scan-To-Bim Creation, William Fulton Ikerd Ii

Electronic Theses and Dissertations

This dissertation presents two contributions to the use of Reality Capture and Scan-to-BIM for facility management (FM). The first manuscript proposes a novel construct for accurately defining scope on Scan-to-BIM projects. Combining the concepts of tolerance, accuracy, and density of point cloud measurements, it will aid laser scan usage in new construction as-built validation, help renovation of existing buildings that lack as-built documentation, and support facility managers who lack accurate plans and digital twins of their buildings by helping determine and communicate the appropriate requirement for Scan-to-BIM. In view of making this process more efficient and cost effective, this article …

Observation Of New Particle Formation In The Northern Hemisphere At Altitude From 4 To 20 Km, Mohamed Saad

Electronic Theses and Dissertations

New particle formation (NPF) is investigated using measurements of aerosol size distributions and meteorological variables made in two continents, including USA and Europe. Despite the considerably different aerosol particle abundances among the sites, a common relationship was found between the characteristics of NPF events and the air mass convective and/or advective transport. CO and O3 act as tracers of tropospheric and stratospheric air, respectively, their statistical relationship can be used to quantify air mass characteristics and origins. The mixing ratio values of CO increased within the upper troposphere layer before/during NPF events, which may serve as an indicator of occurring …

Distributed Control, Optimization, And State Estimation For Renewable Power System, Qiao Li

Electronic Theses and Dissertations

The traditional power systems are usually centralized systems, in which the control, operation and monitoring are performed by the centralized control center, e.g., SCADA. However, with the development of renewable energy, power systems are getting more and more distributed. So, it becomes necessary to establish the distributed power system operation methods for these power systems. In this research, the distributed techniques for the renewable power systems are proposed based on the consensus protocol technique from graph theory. These techniques cover the three important problems in power systems, i.e., economic dispatch, state estimation, and optimal power flow. First, the Distributed Economic …

Design Of Lower Legs Of Mithra, A High-Performance Backdrivable Humanoid Robot, Drake Taylor

Electronic Theses and Dissertations

This thesis presents the design of the knee and ankle of Mithra, a new humanoid robot that aims to be an energy-efficient and highly agile machine. Mithra makes use of new optimization metrics for legged robots to develop a system capable of mimicking human movement. A series of low-impedance, high-torque actuator systems were developed with the goal of creating lightweight, powerful, and robust motion. The structure of Mithra's legs mimics the human structure in leg segment length and weight proportions. Detailed design and analysis were conducted in order to allow Mithra to be a robust and maintainable system. Mithra will …

Design, Manufacture, And Test Of A Hybrid Aerial-Ground Robotic Platform, William Garrett Willmon

Electronic Theses and Dissertations

A hybrid aerial-ground robotic platform allows for enhanced functionality combining most of the operational profiles of an aerial and ground vehicle with applications to intelligence, surveillance, reconnaissance (ISR), infrastructure inspection, emergency response, photography, etc. Motivated by this challenge, we designed, developed, and tested a prototype hybrid aerial-ground robotic vehicle capable of guidance, navigation, and control in the air and on the ground. The thesis focus is on the system design. As such, at first, we designed and analyzed the mechanical component to ensure durability. We then designed the electrical component to reduce overall weight and maximize battery life. We developed …

Mechanisms Of Sensory Adaptation In The Primate Visual System, Boris Isaac Peñaloza Rojas

Electronic Theses and Dissertations

Under ecological conditions, the luminance impinging on the retina varies within a dynamic range of 220 dB. Stimulus contrast can also vary drastically within a scene, and eye movements leave little time for sampling luminance. In addition, the amount of information reaching our visual system far exceeds the brain’s information processing capacity. Given the limited dynamic range of its neurons and its limited capacity in processing visual information in real-time, the brain deploys both structural and functional solutions that work in tandem to adapt to the surroundings. In this work, employing visual psychophysics and computational neuroscience, we study the mechanisms …

Correlating With Local Variation In Collagen Level And Mechanical Properties Of The Heart Tissues, Talayeh Tavangar

Electronic Theses and Dissertations

The determination of the myocardium's tissue properties is essential in constructing finite element (FE) models of the heart. To obtain accurate results, especially for functionally modeling the heart, we must determine the tissue properties in-vivo. The calculation of the heart tissue properties remains a challenging area as it is categorized as a heterogeneous, anisotropic, nonlinear soft tissue that undergoes large deformation. In this work, we tried to introduce and evaluated a finite element method to determine the mechanical properties of the cardiac tissue. The introduced method combined a finite element modeling with the experimentally obtained images from the left and …

Deep Learning Methods For Fingerprint-Based Indoor And Outdoor Positioning, Fahad Alhomayani

Electronic Theses and Dissertations

Outdoor positioning systems based on the Global Navigation Satellite System have several shortcomings that have deemed their use for indoor positioning impractical. Location fingerprinting, which utilizes machine learning, has emerged as a viable method and solution for indoor positioning due to its simple concept and accurate performance. In the past, shallow learning algorithms were traditionally used in location fingerprinting. Recently, the research community started utilizing deep learning methods for fingerprinting after witnessing the great success and superiority these methods have over traditional/shallow machine learning algorithms. The contribution of this dissertation is fourfold:

First, a Convolutional Neural Network (CNN)-based method for …

Recycling Of Fiber Polymer Matrix Composites In Cementitious Materials, Edward Patton Clark

Electronic Theses and Dissertations

Recycling options for fiber polymer matrix composite waste materials are limited because they typically cannot be reused, reprocessed for down-cycling, and are generally environmentally unfriendly. The utility industry, specifically electrical distribution, has been increasingly using hybrid carbon, glass fiber, and epoxy resin composite rods for high-voltage (HV) conductor transmission lines. The high-voltage conductor core (HVCC) used in the transmission line can have an optimal in-service-life of roughly several decades, in which the material is then retired to a waste landfill. Currently, there is limited research and recycling methodology for these hybrid composite rods. In this research, powder carbon fiber, glass …

Optimal Sizing And Operation Of A Pumped Thermal Energy Storage System, Matthew Perez

Electronic Theses and Dissertations

Current trends in the modern grid are leading to the integration of energy storage technologies (ESSs), such as pumped thermal energy storage to help incorporate more variable renewable energy sources into the grid. This paper analyzes the operation of a pumped thermal energy storage (PTES) system under the grid services of energy arbitrage, regulation services, spinning and non-spinning reserve, resource adequacy, and a combination of them all. Each revenue stream is setup into an optimization problem and solved to find which revenue generating technique would generate the most revenue. The combined revenue stream was found to produce the most revenue …

Thermal Performance Of Algan/Gan Based Power Switching Devices For Transformerless Inverters, Mahesh B. Manandhar

Electronic Theses and Dissertations

Wide Bandgap (WBG) semiconductors like Silicon Carbide (SiC), Gallium Nitride (GaN) and Aluminum Gallium Nitride (AlGaN) have superior material properties as compared to Silicon (Si) like higher electrical breakdown voltages and bandgap energies as well as lower leakage currents as compared to Si which make them ideal to operate at higher voltage with lower thermal losses. These properties make WBG materials ideal for power devices like Vertical Double-diffused Metal Oxide Semiconductor Field Effect Transistors (VDMOSFETs). The use of digital prototyping through computer simulation increases the speed and flexibility of the design iterations while reducing the cost and time required for …

Wind Turbine Parameter Calibration Using Deep Learning Approaches, Rebecca Mccubbin

Electronic Theses and Dissertations

The inertia and damping coefficients are critical to understanding the workings of a wind turbine, especially when it is in a transient state. However, many manufacturers do not provide this information about their turbines, requiring people to estimate these values themselves. This research seeks to design a multilayer perceptron (MLP) that can accurately predict the inertia and damping coefficients using the power data from a turbine during a transient state. To do this, a model of a wind turbine was built in Matlab, and a simulation of a three-phase fault was used to collect realistic fault data to input into …

Characterization, Analysis, And Application Of Wbg Power Devices For Future Power Conversion Systems, Ali Mahmoud Salman Al-Bayati

Electronic Theses and Dissertations

Semiconductor power devices are the most momentous constituents of any power converter system. Fast switching, compactness, high performance and efficiency, and high temperature operation are the exacting challenges experienced by conventional silicon (Si) power device based power converters in many applications. In this dissertation, the wide bandgap (WBG) power devices are studied and used to transcend the limitations imposed by the Si power devices. It mainly focuses on characterization and analysis of the behavior of WBG power devices as well as design and development of efficient, high performance, and reliable dc–dc power converters based on WBG technology. First, using computer …

Monitoring Of Overhead Polymer Core Composite Conductors Under Excessive Mechanical Loads Using Fiber Bragg Grating Sensors, Daniel H. Waters

Electronic Theses and Dissertations

This combined experimental and numerical study addresses mechanical effects associated with static and dynamic loading of novel High Temperature Low Sag (HTLS) transmission line polymer core composite conductors. The developed methodology was successfully applied to ACCC® to explain the complex failure mechanisms associated with combined bending and tension loading. Furthermore, the use of Fiber Bragg Grating (FBG) sensors was investigated for the first time to monitor the ACCC® design during installation and in-service.

Transverse low-velocity impacts to the ACCC® conductor having either free or constrained end conditions and large axial tensile loads were performed. It was identified that the most …

Surface And Interfacial Phenomena Between Soil And Oil, Md Firoz Ahmed

Electronic Theses and Dissertations

Crude oil and motor oil spills on land have severe environmental consequences that pose threats to both humans and natural resources. It is particularly important to know the flow behavior of oils to protect terrestrial ecosystems from this kind of damage. The spreading kinetics, contact angle (CA), and droplet baseline studies of crude oil and motor oils were investigated over several realistic soil-based matrices composed of topsoil (silt-dominant), sand, clay, and moisture. It was found that with an increase in moisture content (MC), the spreading area decreased, and initial spreading time increased for all given oil. The initial CA generally …

Solubility Measurements Of Hydrophobic Solutes In Supercritical Carbon Dioxide And Subsequent Impregnation Into Paper Substrates For Surface Modifications, Arghavan Beheshtimaal

Electronic Theses and Dissertations

Supercritical Fluids (SCFs) have received a great deal of attention for their various applications in chemical, biochemical, pharmaceutical, and materials processing. In this study, we investigate surface modification to paper substrates using supercritical impregnation (SCI) techniques, with applications in food packaging. One of the key factors required for this study is understanding the solubility of hydrophobic solutes in supercritical carbon dioxide (scCO2). Polar compounds are poorly soluble in scCO2 due to their lack of polarity and frequently co-solvents are also introduced to enhance solubility. In this study, the maximum solubility of alkyl ketene dimer (AKD)/n-heptane and vegetable wax (VW)/n-heptane solutions …

Develop Biochar-Based Controlled Release Nitrogen Fertilizers, Zhisheng Cen

Electronic Theses and Dissertations

The current efficiency of conventional nitrogenous fertilizers (e.g. urea, ammonium sulfate, etc.) in agricultural practices is low, fluctuating from 30 to 40%. Approximately 60% of nitrogenous fertilizers were wasted due to vaporization into the air, runoff or leaching into water systems. The lost nitrogen (N) resulted in not only high production cost but also serious environmental problems, such as greenhouse gas (N2O) emission in the atmosphere, algal blooms, oxygen depletion, fish kills, and loss of biodiversity in surface water due to eutrophication or pollution. To address these problems, this study aimed to utilize low-cost biochar-based materials to develop a controllable, …

Nanoscale Spatial Realization Of Grain Boundary Defects And Its Passivation In Perovskite Solar Cells, Ashraful Haider Chowdhury

Electronic Theses and Dissertations

Perovskite solar cells (PSCs) have seen significant improvement in photovoltaic performance in recent days. However, the performance of PSCs is limited by the defects present at grain boundaries (GB). The study adapted here discusses the nanoscale spatial realization of grain boundary defects and its passivation in perovskite solar cells. Conventional MAPbI3 and state- of-the-art Cs5(MA0.17FA0.83)95Pb(I0.83Br0.17)3-FAMACs perovskite GBs were studied in detail using atomic force microscopy. The density of trap states calculation by kelvin probe force microscopy (KPFM) shows that FAMACs perovskites have lower defects at GB compared with MAPbI3 perovskites. This improvement is caused by the less activation energy of …