Engineering Commons^™

Data-Driven Deep Learning-Based Analysis On Thz Imaging, Haoyan Liu

Graduate Theses and Dissertations

Breast cancer affects about 12.5% of women population in the United States. Surgical operations are often needed post diagnosis. Breast conserving surgery can help remove malignant tumors while maximizing the remaining healthy tissues. Due to lacking effective real-time tumor analysis tools and a unified operation standard, re-excision rate could be higher than 30% among breast conserving surgery patients. This results in significant physical, physiological, and financial burdens to those patients. This work designs deep learning-based segmentation algorithms that detect tissue type in excised tissues using pulsed THz technology. This work evaluates the algorithms for tissue type classification task among freshly …

Ultrasound Mediated Tissue Growth In Bioinspired Scaffolds, Marco Fielder

Graduate Theses and Dissertations

Porous scaffolds mechanically stimulated with ultrasound are used for the treatment of bone conditions such as osteoporosis or traumatic bone injury. However, one current issue in these treatment techniques is designing a scaffold structure with a high structural integrity that also does not impede tissue growth. A larger ultrasound wave transmission would also allow more of a scaffold to receive mechanical stimulation from ultrasound. Controlling mesenchymal stem cell seeding of tissue scaffolds also has potential for developing optimal seeding patterns to maximize or control tissue growth in the scaffold based on an individual’s physiology. There is also a need for …

Hierarchical Structure And Material Integration For Electrocatalytic Co2 Reduction, Hamed Mehrabi

Graduate Theses and Dissertations

CO2 released by the combustion of fossil fuels is driving significant changes to the earth’sclimate. The natural cycle for removing CO2 from the atmosphere, namely photosynthesis, cannot keep up with the rate at which it is being added. Developing engineering approaches to remove CO2 from the atmosphere is becoming essential to reduce these effects. Removal leads to further issues of carbon sequestration and favorable CO2 reuse strategies, including the electrochemical transformation of recovered CO2 to useful products such as fuels and materials. Copper is an important electrocatalyst for the CO2 reduction reaction (CO2RR) because of its unique capability for producing …

Electrical Modeling For Dynamic Performance Prediction And Optimization Of Mcpms Layout, Quang Minh Le

Graduate Theses and Dissertations

In recent years, the fast development of Multichip Power Modules (MCPM) packaging and Wide Bandgap (WBG) technology has enabled higher voltage and current ratings, better thermal performance, lower parasitic parameters, and higher mechanical reliability. However, the design of the MCPM layout is a multidisciplinary problem leading to many time-consuming analyses and tedious design processes. Because of these challenges, the design automation tool for MCPM layout has become an emerging research area and gained much attention from the power electronics community. The two critical objectives of a design automation tool for MCPM layout are fast and accurate models for design insights …

Reliability Enhancing Control Algorithms For Two-Stage Grid-Tied Inverters, Yuheng Wu

Graduate Theses and Dissertations

In the photovoltaic (PV) generation system, two types of grid-tied inverter systems are usually deployed: the single-stage grid-tied inverter system and the two-stage grid-tied inverter system. In the single-stage grid-tied inverter system, the input of the inverter is directly connected to the PV arrays, while an additional dc-dc stage is inserted between the PV arrays and the dc-ac inverter in the two-stage design. The additional dc-dc stage could provide a stable dc-link voltage to the inverter, which also enables new design possibilities, including the multi-MPPT operation and solar-plus-storage application. Thus, the two-stage grid-tied inverter has been widely used in the …

Using Copper Oxide And Zwitterions To Prevent Membrane Fouling And Optimizing Ultrafiltration Membrane Fabrication With Green Solvents, Cannon Hackett

Graduate Theses and Dissertations

Membrane fouling and sustainable production of membranes are two of the most important challenges in membrane science. Chapter 1 of this dissertation introduces these challenges and covers previous research that has been done in those areas. Additionally, the objectives of this dissertation are stated. In chapter 2, a study was done in which polyethersulfone ultrafiltration membranes were functionalized with copper oxide nanoparticles and zwitterions for the purpose of reducing fouling on the membrane surface. Characterization confirmed the attachment of each component to the membranes. Dead-end filtration was performed with water and bovine serum albumin solution and showed that the functionalization …

Precision Weed Management Based On Uas Image Streams, Machine Learning, And Pwm Sprayers, Jason Allen Davis

Graduate Theses and Dissertations

Weed populations in agricultural production fields are often scattered and unevenly distributed; however, herbicides are broadcast across fields evenly. Although effective, in the case of post-emergent herbicides, exceedingly more pesticides are used than necessary. A novel weed detection and control workflow was evaluated targeting Palmer amaranth in soybean (Glycine max) fields. High spatial resolution (0.4 cm) unmanned aircraft system (UAS) image streams were collected, annotated, and used to train 16 object detection convolutional neural networks (CNNs; RetinaNet, Faster R-CNN, Single Shot Detector, and YOLO v3) each trained on imagery with 0.4, 0.6, 0.8, and 1.2 cm spatial resolutions. Models were …

Integrative Physiology-Coupled Pilot-Centered Flight Simulation, Shawn C. Harrison

Electrical & Computer Engineering Theses & Dissertations

Maintaining the pilot’s physiological performance envelope within the limits of human capabilities may be crucial for avoiding hazardous physiological episodes in fighter aircraft that compromise safety. The main physiological episode of interest is impaired pilot respiration, better known as hypoxia caused by a high fraction of inspired oxygen (FiO₂) at high altitudes and variation in accelerative gravitational forces (g-forces). Integrated into fighter aircraft is an Onboard Oxygen Generating System (OBOGS) developed to mitigate the necessity of gaseous and liquid oxygen cannisters [1]. OBOGS act as a life support in hypoxic environments by providing oxygen-rich air, thereby oxygenating the …

Effectiveness Of Suspended Lead Dampers In Steel Buildings Under Localized Lateral Impact And Vertical Pulsating Load, Herish Abdullah Hussein

Civil & Environmental Engineering Theses & Dissertations

Presented herein is a study of the effectiveness of suspended lead dampers for use in steel buildings under a localized impact load and a vertical pulsating load. A series of lead spheres mounted on a string are suspended inside the building columns or damping panels to absorb the energy of vibration through a collision between the lead dampers and internal surfaces of the members. Experiments are conducted on a three-story steel building model and a cantilever member with suspended lead dampers and subjected to localized impact loading. The cantilever under impact load is analyzed with a partial differential equation of …

Characterization Of Losses In Superconducting Radio-Frequency Cavities By Combined Temperature And Magnetic Field Mapping, Ishwari Prasad Parajuli

Physics Theses & Dissertations

Superconducting radio-frequency (SRF) cavities are one of the fundamental building blocks of modern particle accelerators. To achieve the highest quality factors (10¹⁰-10¹¹), SRF cavities are operated at liquid helium temperatures. Magnetic flux trapped on the surface of SRF cavities during cool-down below the critical temperature is one of the leading sources of residual RF losses. Instruments capable of detecting the distribution of trapped flux on the cavity surface are in high demand in order to better understand its relation to the cavity material, surface treatments and environmental conditions. We have designed, developed, and commissioned two novel …

A Systems Theory-Based Framework For Environmental Scanning In Complex System Governance, Dale E. Baugh

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this research was to develop a Systems Theory-based framework for Environmental Scanning (ES) in Complex System Governance (CSG) using an inductive research design. Complexity and uncertainty are normal for external environments in which today’s systems (organizations) exist. These environmental characteristics provide impetus for researchers to focus on organizational planning for disruptive external forces that could threaten system stability and future system existence. The ES function supports the requisite governance metasystemic functions to be enabled, executed, and evolved sufficiently well to promote continuous system viability. In this research the functioning of ES was examined from a diverse literature-based …

Numerical Simulation Of Electroosmotic Flow Of Viscoelastic Fluid In Microchannel, Jianyu Ji

Mechanical & Aerospace Engineering Theses & Dissertations

Electroosmotic flow (EOF) has been widely used in various biochemical microfluidic applications, many of which often involve the use of viscoelastic non-Newtonian fluids. Due to the existence of the elastic effect, the viscoelastic EOF develops into chaotic flow under extremely low Reynolds numbers, which is known as elastic turbulence. The mechanism of elastic turbulence in electroosmotic flow remains unclear. Numerical simulation plays an important role in understanding the mechanisms of elastic turbulence. This dissertation is aimed to study the EOF of viscoelastic fluids in constriction microchannels under various direct current (DC) and alternating current (AC) electric fields. First, the EOF …

Assembly Of Ceramic Particles In Aqueous Suspensions Induced By High-Frequency Ac Electric Field, James E. John Iv

Mechanical & Aerospace Engineering Theses & Dissertations

Ceramic materials processed using colloidal methods have been the focus of a great deal of research aimed at tailoring the final structure and microstructure of the finished ceramic sample. To this end, various external field effects have been investigated to modify the suspension microstructure without manipulating the ceramic particles directly. In a previous work in the field of ice templating it has been shown that AC electric fields are able to produce microstructural changes in ice templated ceramics that have significantly improved the final mechanical properties. However, the mechanisms for this process are still not well understood in ceramics.

To …

E-Beam Irradiation Beamline At Jefferson Lab For Wastewater Treatment, Xi Li

Electrical & Computer Engineering Theses & Dissertations

Electron beam (e-beam) irradiation is an advanced method for removing the emerging organic contaminants in wastewater, such as 1,4-dioxane, and per- and polyfluoroalkyl substances (PFAS), which have the potential to be regulated in the near future but are difficult to degrade by conventional treatment methods. This dissertation was based on a collaborating study between Jefferson Lab (Jlab) and Hampton Roads Sanitation District (HRSD) to evaluate the impacts of e-beam irradiation on the degradation of 1,4-dioxane and PFAS. It presents the detailed design of an e-beam irradiation beamline, the beamline simulation using general particle tracer (GPT), the installation, and the successful …

Detection, Tracking, And Classification Of Aircraft And Birds From Multirotor Small Unmanned Aircraft Systems, Chester Valentine Dolph

Electrical & Computer Engineering Theses & Dissertations

The ability for small Unmanned Aircraft Systems (sUAS) to safely operate beyond visual line of sight (BVLOS) is of great interest to governments, businesses, and scientific research. One critical element for sUAS to operate BVLOS is the capability to avoid other air traffic. While many aircraft will be cooperative and broadcast their locations using Automatic Dependent Surveillance Broadcast (ADS-B), it is expected that many aircraft will remain non-cooperative – meaning they do not communicate position or flight plan to other aircraft. Avoiding mid-air collisions with non-cooperative aircraft is a critical limitation to widespread sUAS flying BVLOS. Examples of non-cooperative traffic …

Lifting-Line Predictions For Life And Twist Distributions To Minimize Induced Drag In Ground Effect, Kyler Church

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The elliptic lift distribution produces the minimum induced drag for a given wingspan and desired lift outside of ground effect. This distribution can be generated on any wing by using geometric and/or aerodynamic twist. However, in ground effect, the elliptic lift distribution is not necessarily that which minimizes induced drag. The present work uses a modern numerical lifting-line algorithm to evaluate how the optimum lift distribution varies as a function of height above ground. The algorithm is also used to obtain the twist distributions that should be applied to wings of varying aspect ratios and taper ratios to produce the …

A Theoretical Trade-Off Between Wave Drag And Sonic Boom Loudness Due To Equivalent Area Changes On A Supersonic Body, Nolan L. Dixon

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The NASA University Leadership Initiative (ULI) titled ”Adaptive Aerostructures for Revolutionary Civil Supersonic Transportation” consists of a team of university and industry partners studying the feasibility of reducing the perceived loudness of the sonic boom by introducing an adaptive geometry at localized regions of an aircraft’s outer-mold line. The Utah State University AeroLab is a member of this ULI team and has produced low-fidelity tools to predict the aerodynamic and boom loudness effects from localized changes to the geometry.

Such changes to the geometry affect both the sonic boom loudness and wave drag; however, the precise relationship between boom loudness …

Multi-Fidelity Predictions For Control Allocation On The Nasa Ikhana Research Aircraft To Minimize Drag, Justice T. Schoenfeld

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Optimal control settings (camber scheduling) can be used by aircraft to minimize drag at various operating conditions during flight. In this work, camber schedules for minimum drag on the NASA Ikhana are obtained over a range of lift coefficients. A modern numerical lifting-line algorithm is used to predict the lift and drag of the aircraft as a function of operating condition and wing section shape (airfoil camber). The SLSQP optimization algorithm is used to solve for the camber schedule that minimizes drag for a given operating condition. The process is repeated, varying the number of control sections to evaluate the …

Characterizing Karst Mountain Watersheds Through Streamflow Response To Snowmelt, Daniel Meade Thurber

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The climate in many parts of the Western US is characterized by cold, wet winters preceding long, dry summers. In the absence of precipitation, water supplies in these regions are sustained by melting snow and mountain groundwater. Changes in regional climate can reduce snow accumulation, accelerate melt, and prolong dry periods, all increasing the importance of groundwater on summertime water availability. In mountainous regions with limestone and dolomite geology, bedrock formations can host significant karst aquifers comprising dissolution-enhanced karst conduits which play an outsized and variable role in how precipitation is translated into streamflow. In this study, we considered an …

Developing A Methane Detector For Aerospace Applications, Michael A. Kirk

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Greenhouse gasses in the atmosphere are raising the global temperature and causing adverse side effects. Of these greenhouse gasses, methane is one of the most impactful, second only to carbon dioxide. One of the methods for determining the concentration of methane in the atmosphere is taking images of the earth from space. The purpose of this project is to further a new imaging technology for detecting methane leaks called FINIS (Filter Incidence Narrow-band Infrared Spectrometer), thus improving our capability to detect and locate methane leaks and reduce greenhouse gas emissions. FINIS has been developed in various stages since 2018 and …

Low Resource Assay For Tracking Sars-Cov-2 In Wastewater, Julissa Van Renselaar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wastewater based epidemiology (WBE) allows for the tracking of nucleic acid of SARS-CoV-2 in wastewater which gives the opportunity for the public and government officials to be informed about the infectivity of the virus in a community. Advances have been made in WBE that have allowed for higher performance, lower resource use, and faster turnaround time. An adapted concentration method of spin column direct extraction has yielded a proxy virus recovery of 83%, consumable cost of $2.01 per sample, and a turnaround time of 0.33 hour/sample. Other concentration methods have lower proxy virus recoveries, comparable cost, and comparable turnaround time. …

Numerical Modeling And Simulating Thermal Performance Of Printed Circuit Boards, Paul R. Ziegenfelder

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research investigates how heat transfer theory can be applied to evaluate the thermal performance of printed circuit board (PCB) designs. A model was developed for correlating theory to the physical parameters relating to the construction of the PCB and a computer application was developed to perform the thermal analysis. The application allows the importation of common PCB design files for a straightforward and quick analysis of a PCB design’s thermal performance. The application is open-source to allows for further development and free access from the public.

Event-Based Obstacle Detection With Commercial Lidar, Chaz Cornwall

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Computerized obstacle detection for moving vehicles is becoming more important as vehicle manufacturers make their systems more autonomous and safe. However, obstacle detection must operate quickly in dynamic environments such as driving at highway speeds. A unique obstacle detection system using 3D changes in the environment is proposed. Furthermore, these 3D changes are shown to contain sufficient information for avoiding obstacles. To make the system easy to integrate onto a vehicle, additional processing is implemented to remove unnecessary dependencies. This system provides a method for obstacle detection that breaks away from typical systems to be more efficient.

Modeling And Control Of Battery Management Systems With High-Frequency Ac Link Coupled Multiport Series Resonant Converters For 2nd Life Battery Applications, Brooks Jace Maughan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

While the use and production of Electric Vehicles becomes more prevalent, it is also important to make this economical and ensure the reduction of a carbon footprint. Second-life batteries can satisfy both problems as batteries can be used in a second-life application for lower power purposes such as supplementing the grid so the infrastructure needed to charge the expanding fleet of Electric Vehicles can be easily supplied. This thesis goes through the process of Active Cell Balancing which will produce equal capacities, or similar batteries, that can be more efficiently used in these and other types of second-life applications. The …

Path Planning For Aircraft Under Threat Of Detection From Ground-Based Radar With Uncertainty In Aircraft And Radar States, Austin D. Costley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Mission planners for manned and unmanned aircraft operating within the detection range of ground-based radar systems are often concerned with the probability of detection. Several factors influence the probability of detection, including aircraft position and orientation, radar position, and radar performance parameters. Current path planning algorithms assume that these factors are known with certainty, but in practice, these factors are estimated and have some uncertainty.

This dissertation explores methods to consider the uncertainty in the detection factors for an aircraft path planner. First, the detection model is extended to include uncertainty in the aircraft position and orientation, radar position, and …

Design Of Environment Aware Planning Heuristics For Complex Navigation Objectives, Carter D. Bailey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A heuristic is the simplified approximations that helps guide a planner in deducing the best way to move forward. Heuristics are valued in many modern AI algorithms and decision-making architectures due to their ability to drastically reduce computation time. Particularly in robotics, path planning heuristics are widely leveraged to aid in navigation and exploration. As the robotic platform explores and navigates, information about the world can and should be used to augment and update the heuristic to guide solutions. Complex heuristics that can account for environmental factors, robot capabilities, and desired actions provide optimal results with little wasted exploration, but …

Optimization And Enhancement Of Co2 Sequestration In Industrial Wastes For Environmental Applications, Maisa El Gamal, Ameera F. Mohammad

All Works

This paper explores carbon capture and storage (CCS) through carbide lime waste (CLW), a by-product of acetylene production, under different conditions. This process is specifically designed to provide an onsite waste management solution for several industries that can easily be integrated into existing systems. In addition, the effect of the carbonation process on collected solids morphology and average particle size was studied. The structural and chemical characteristics of the carbonated carbide lime samples were investigated using X-ray diffraction, scanning electron microscopy, TGA analysis, and Raman spectroscopy. The effect of carbonation conditions on the total dissolved solids and change in pH …

Instance Segmentation-Based Depth Completion Using Sensor Fusion And Adaptive Clustering For Autonomous Vehicle Perception, Mohammad Z. El-Yabroudi

Dissertations

Depth sensing is critical for safe and accurate maneuvering in robotics and self-driving car (SDC) applications. Most recent LiDAR sensors, such as Ouster and Velodyne, offer 360 degrees of scanning at the rate of ten frames per second, making them very appropriate for autonomous driving applications. However, LiDAR point cloud data show many shortcomings, especially its data sparsity and unassigned nature, making it very challenging to utilize in applications such as perception, 3D object detection, 3D scene reconstruction, and simultaneous localization and mapping.

In this study, a novel framework using instance image segmentation and the raw LiDAR data for the …

Engineer And Test A Biodegradable Microneedle Patch To Deliver Meloxicam For Managing Pain In Cattle, Katherine Alejandra Miranda Munoz

Graduate Theses and Dissertations

Microneedle patches are a promising source for transdermal diffusion of macromolecules and are designed to painlessly penetrate the skin. In this study, a biodegradable chitosan microneedle patch to deliver meloxicam for managing pain in cattle was tested. The potential of reuse of the polymeric solution to fabricate the patches, optimization of fabrication, morphological analysis of the microneedle patch and analysis of preservation of the chemical composition after sterilization were evaluated. In-vitro analysis consisted of studying in-vitro penetration mechanical properties, compression testing analysis of microneedle patch, and in-vitro drug release analysis. In-vivo studies were performed to analyze the dissolution capability of …

Fiber-Based Time-Correlated Single Photon Counting As A Method For Investigating Metabolism During Tetanic Contraction Of Skeletal Muscle, Kathryn Miller Priest

Graduate Theses and Dissertations

Nicotinamide adenine dinucleotide (NAD) is a cofactor that serves to shuttle electrons during metabolic processes such as glycolysis, the tricarboxylic acid cycle, and oxidative phosphorylation (OXPHOS) [1-5]. The reduced form of NAD, NADH, is autofluorescent, making it a measurable characteristic in the investigation of metabolic changes. The fluorescence lifetime of NADH is dependent on the state of protein binding, specifically free or bound NADH, allowing for detection of metabolic shifts between glycolysis (free NADH) and OXPHOS (bound NADH) [6-16]. Fiber-coupled time-correlated single photon counting (TCSPC) equipped with an implantable needle probe can be used to measure NADH lifetime in vivo …