Engineering Commons^™

The Effects Of Various Inlet Distortion Profiles On Transonic Fan Performance, Andrew Michael Bedke

Theses and Dissertations

An increased understanding of how inlet flow distortion affects transonic fans enables improved fan design and performance prediction. Inlet distortion refers to non-uniformities in the incoming flow properties. Complex inlet ducts in high performance aircraft result in distorted flow at the fan inlet. In this thesis, two studies were performed using Unsteady Reynolds-Averaged Navier Stokes (URANS) simulations. The first study focused on understanding how the transition abruptness between the clean and distorted sector in the inlet Pt profile as well as the circumferential extent of the distorted sector affect distortion transfer and generation through a transonic fan. Simulations on two …

Mechanisms For Improvement Of Key Mechanical Properties In Polymer Powder Bed Fusion Processes, Clinton Spencer Abbott

Theses and Dissertations

The purpose of this work is to understand the reasons for varied mechanical properties among three polymer Powder Bed Fusion (PBF) Additive Manufacturing (AM) processes. Parts for this work were manufactured from Polyamide 12 (PA12) using the Laser Powder Bed Fusion (L-PBF), Multi-Jet Fusion (MJF), and the recently developed Large Area Projection Sintering (LAPS) processes. Previous works have shown that LAPS parts demonstrate significantly higher density, ductility, and toughness than parts from the L-PBF and MJF processes. A hot isostatic pressing (HIP) treatment was developed to reduce porosity in L-PBF and MJF parts and determine if increasing part density would …

Systems Engineering Of The Global L-Band Observatory For Water Cycle Studies, James Nathan Smith

Theses and Dissertations

The Global L-band Observatory for Water Cycle Studies (GLOWS) is designed as a follow-on to the Soil Moisture Active Passive (SMAP) observatory launched in 2015. While GLOWS is essentially copying many aspects of the SMAP mission, a key change has been made in the antenna technology. SMAP uses a reflector antenna and to reduce mission costs GLOWS uses a metamaterial lens antenna. This type of antenna is less efficient, so it must be proven that GLOWS can achieve the same uncertainty levels in soil moisture measurements as SMAP. In this work, a unified framework for modeling and analyzing GLOWS' ability …

Development Of Compact Phased Array Receivers On Rfsoc Prototyping Platforms, Jacob Bartschi

Theses and Dissertations

The continual increase of wireless technologies in the world has motivated the use of phased arrays to mitigate radio frequency interference (RFI). There are many methods of performing beamforming for RFI rejection, but they are traditionally physically large and complicated solutions. Phased arrays need to be shrunk and made cheaper for them to see widespread use. This work presents several compact phased array receivers for different applications. The first part of this thesis presents a software GPS processor for a digital beamforming GPS receiver. The receiver is small enough to be flown on drones and enables GPS signals to be …

Effects Of Optical Configuration And Sampling Efficiency On The Response Of Low-Cost Optical Particle Counters, Brady Scott Hales

Theses and Dissertations

Hazards associated with air pollution motivate the search for technologies capable of monitoring individual exposure to gaseous pollutants and particulate matter (PM). A Low-cost Optical Particle Counter (OPC), costing less than 50 USD, is an example of such technologies. Currently, OPCs are widely used to measure the concentration of particle matter in ambient air. While these low-cost air quality sensors are widely available, the accuracy and precision of these devices is highly uncertain. Consequently, the purpose of this thesis is to present an analytical model of two generic, low-cost OPCs based on the Laws of Conservation of Mass, Momentum, and …

Gradient-Based Wind Farm Layout Optimization, Jared Joseph Thomas

Theses and Dissertations

As wind energy technology continues to mature, farm sizes grow and wind farm layout design becomes more difficult, in part due to the number of design variables and constraints. Wind farm layout optimization is typically approached using gradient-free methods because of the highly multi-modal shape of the wind farm layout design space. Gradient-free method performance generally degrades with increasing problem size, making it difficult to find optimal layouts for larger wind farms. However, gradient-based optimization methods can effectively and efficiently solve large-scale problems with many variables and constraints. To pave the way for effective and efficient wind farm layout optimization …

Implementation Of An Api For And The Folding Of Fpga Routing Resource Graphs In Vtr, Ethan Steiner Rogers

Theses and Dissertations

FPGAs provide parallel computing that is fit for speeding up the computation of a large range of problems. Programming an FPGA involves a complex tool flow for which several CAD tools have been developed. These tools compute solutions to many problems such as packing, placement, and routing, which map a circuit design onto an FPGA. These computations require a great deal of memory, of which the Routing Resource Graph contributes the most of any individual data structure. If the RRGraph could be represented in a more compact manner, performance of the tool flow algorithms may be improved due to an …

Parametric Models Of Maize Stalk Morphology, Michael Alan Ottesen

Theses and Dissertations

As the most produced grain crop world-wide, 5% of corn is lost due to stalk lodging (above-ground structural failure of the stalk near the roots). Current modeling methods lack the ability to manipulate the stalk architecture. In contrast, parameterized models enable advanced analyses such as sensitivity and optimization studies. This thesis advances previous work on a parameterized cross-sectional model of maize stalk morphology and investigates the validity of a parameterized three-dimensional model. The parameterized cross-sectional model is based upon previous work that approximated the cross-section of maize stalks using an ellipse plus principal components. Validation of the cross-sectional model was …

Sub-Grain Characterization Of Slip Activity In Bcc Tantalum, Tristan Kirby Russell

Theses and Dissertations

BCC metals are commonly used throughout the world and understanding their deformation behavior, especially at the sub-grain level, is essential for their continued use in technological advancements. Correctly and confidently characterizing the active slip systems in BCC materials has been a difficult task throughout past research. The research described in this thesis utilizes high resolution digital image correlation (HRDIC) and relative displacement ratio (RDR) analysis to accurately characterize active slip systems in large grained BCC tantalum and provides new insights into dislocation nucleation sites, relative CRSS values for {110} and {112} slip systems, the correlation between GB transmission factors and …

Flexural Strength And Behavior Of Timber-Concrete Composite Floors With Hexagonally Headed Self-Tapping Screw Shear Connectors, Benjamin David Arrington

Theses and Dissertations

Timber-concrete composite (TCC) floor systems consist of a bottom layer of wood that is connected to a top layer of concrete using shear connectors. The shear connectors resist slip between the layers, thus allowing wood and concrete develop composite action when subjected to flexure. The objective of this study is to determine the flexural strength and behavior of TCC floor systems that consist of a cross laminated timber wood layer connected to a concrete top layer using hexagonally headed self-tapping screw shear connectors. To accomplish the objective, coupon specimens and full-scale TCC floor panels were tested, and a finite element …

On The Development And Use Of A Micro-Surface Probe For Measurement Of Li-Ion Battery Electrical Properties, John Eric Vogel

Theses and Dissertations

Rechargeable lithium-ion batteries are a staple of modern society, providing power to a significant portion of the world's electronics and rapidly replacing older power sources. The advent of widely available electric cars with batteries of up to 200 kWh, with an increasing emphasis on fast charging, has only increased their importance. Lithium-ion battery electronic and ionic properties are largely determined by the microstructure of the battery electrode film and can be heavily influenced by relatively small variations in film makeup, including the formation of voids or distribution of carbon and binder. Prior to this research, electrical properties, which are some …

Optical Observation Of Large Area Projection Sintering, Derek Black

Theses and Dissertations

Polymer powder bed fusion (PBF/P) is one of many additive manufacturing (AM) processes utilized for producing polymer parts from digital 3D models. AM is preferred over traditional manufacturing methods in many applications due to advantages including tool-less manufacturing, high geometric complexity, short lead times, and reduced material waste. However, many industries that stand to benefit the most from AM are limited in their ability to use AM parts in large part due to low confidence in AM part quality. Among the polymer AM processes, PBF/P processes show significant promise for these applications due to their comparatively high isotropy and mechanical …

Motion Analysis Of Physical Human-Human Collaboration With Varying Modus, Seth Michael Freeman

Theses and Dissertations

Despite the existence of robots that are capable of lifting heavy loads, robotic assistants that can help people move objects as part of a team are not available. This is because of a lack of critical intelligence that results in inefficient and ineffective performance of these robots. This work makes progress towards improved intelligence of robotic lifting assistants by studying human-human teams in order to understand basic principles of co-manipulation teamwork. The effect of modus, or the manner in which a team moves an object together, is the primary study of this work. Data was collected from over 30 human-human …

A Component-Based Analysis For Online Proctoring, Salma Roshdy Ali

Theses and Dissertations

The switch to online learning due to the COVID-19 revealed flaws in the existing learning methods, especially with online proctored assessments. Hence, online proctoring using computers was needed for a fair evaluation. Many studies develop cheating detection systems using several approaches. However, to the best of our knowledge, none of the existing studies investigated the impact of their system components in detecting cheating behaviors. Combining system components, even if they do not significantly improve the system performance in cheating detection, can cause an overload on the system. Therefore, our goal is to investigate the system components’ impact, individually and combined, …

The Effect Of Concrete Material Properties On Rigid Pavement Design In South Carolina, Nicolet Anne Devine

Theses and Dissertations

This thesis presents the effect of concrete material inputs on rigid pavement design in the state of South Carolina. The impact of concrete strength input parameters in the historical AASHTO pavement design method and MEPDG method is investigated using three newly constructed concrete sections, I-85 in Cherokee County, I-20 in Lexington County, and I-85 in Spartanburg County. Strength data obtained from the sections were the result of QA/QC testing provided by the SCDOT during construction, as well as from UofSC laboratory testing. The compressive strength data from these tests was correlated to the elastic modulus and modulus of rupture (which …

Synthesis, Characterization And Evaluation Of Dilute Limit Alloy Bimetallic Catalysts For Bio-Oil Upgrading, Leandro Tagum De Castro

Theses and Dissertations

Well-defined single-atom catalytic sites with unique geometric and electronic properties are at the forefront of catalyst research. One type of SAC is a so-called dilute limit alloy (DLA), where single metal atom sites are supported on (or in) the surface of a second metal. This category of well-dispersed atoms alloyed on a metal surface has shown to be effective in reactions like selective hydrogenation of alkynes and dienes to alkenes, ethanol dehydrogenation, and the Ullmann reaction of aryl chlorides. In biomass conversion, this type of catalyst may find its way to address and improve conversion and yield that are crucial …

Thermal-Hydraulic System Analysis Of A Proposed 1 Mwth Nuclear Gas Cooled Microreactor, Aaron S. Fernandez

Theses and Dissertations

Nuclear power plants have historically been large, expensive, and prolonged construction projects. A new generation of reactors categorized as microreactors is currently being designed to address energy needs in remote locations. The University of South Carolina has proposed the MIcro Nuclear In ONe megawatt (MINION-1) design to achieve ten years of operation. The primary loop transfers 1 MW of energy from the reactor core using helium, while the secondary uses air in an open Brayton cycle to produce power and heat. This work focuses on modeling the MINION-1 design using the System Analysis Module (SAM) developed by Argonne National Labs …

Growth, Characterization And Evaluation Of Cdzntese Single Crystals For Room Temperature Radiation Detectors, Ritwik Nag

Theses and Dissertations

In this research work Cd_0.9Zn_0.1Te_0.03Se_0.97 (CZTS) single crystals were grown using in-house zone refined 7N (99.99999%) purity elements through vertical Bridgman (VBM) method and vertical gradient freeze (VGF) method. The morphological, compositional, and structural characteristics were then performed on the grown CZTS crystals. The x-ray diffraction (XRD) analysis on the grown crystals showed sharp diffraction peaks indicating a highly crystalline nature, with a lattice constant of ~6.45 Å. The elemental and stoichiometric ratio of the grown CZTS crystals were examined by using energy-dispersive x-ray analysis (EDX), which confirmed the formation of the quaternary …

Concurrent Identification, Characterization, And Reconstruction Of Protein Structure And Mixed-Mode Dynamics From Rdc Data Using Redcraft, Hanin Rafiq Omar

Theses and Dissertations

A complete understanding of the structure-function relationship of proteins requires an analysis of their dynamic behaviors and the static structure. However, all current approaches to studying dynamics in proteins have their shortcomings. A conceptually attractive and alternative approach simultaneously characterizes a protein's structure and its intrinsic dynamics⁠. Ideally, such an approach could solely rely on RDC data-carrying both structural and dynamical information. The major bottleneck in utilizing RDC data in recent years has been attributed to a lack of RDC analysis tools capable of extracting the pertinent information embedded within this complex data source.

Here we present a comprehensive strategy …

Catalytic Cracking Of Oxygenated Polymer Waste Via Zeolite Catalysts, Andrew Jaeschke

Theses and Dissertations

Plastic recycling has been a prevalent issue since the commercialization of plastics due to lack of adoption and insufficient technology. There are many different types of plastics used in modern day society; however, majority of recycling efforts are focused solely on polyethylene terephthalate (PET) and polyethylene plastics. Some of these overlooked plastics include polyols and polyurethanes, which can be found in a variety of applications including furniture stuffing, adhesives, and insulation foams. Recently, plastic research has turned to catalytic cracking units as a means of plastic recyclability. Catalytic cracking of hydrocarbons is a field dominated by zeolites catalysts, especially ZSM-5. …

Epitaxial 4h-Sic Radiation Detectors For Harsh Environment Applications, Joshua W. Kleppinger

Theses and Dissertations

Epitaxial 4H-silicon carbide (4H-SiC) is an essential semiconductor material for the development of harsh environment radiation detectors due to its excellent electrical and thermal properties and resistance to radiation damage, opening the door for a wide variety of applications in NASA space missions, nuclear safeguards, and nuclear energy. However, the low atomic numbers of its constituent atoms Si (Z = 14) and C (Z = 6) make 4H-SiC nearly transparent to most neutrally charged radiation which can only be compensated using thicker active volumes.

In this dissertation, Ni/n-4H-SiC Schottky barrier diode (SBD) radiation detectors are fabricated for the first time …

Fundamental Study Of Multiphase Solid/Molten Carbonate Membranes For Co2 Capture And Conversion, Xin Li

Theses and Dissertations

Due to the burning of fossil fuels and human activities, many greenhouse gases such as carbon dioxide are released into the atmosphere, which causes global warming and has a significant negative impact on the human living environment. Therefore, it is imperative to develop carbon capture technologies that can prevent carbon dioxide emission and reduce carbon dioxide concentration in the air. Further, if the captured carbon dioxide can be converted back to fossil fuels, the emission of carbon dioxide is delayed, and more time is gained to develop new and advanced carbon free and clean energy technologies. Motivated by this thought, …

Advancement Of New Solid-Oxide Iron-Air Battery (Soiab) Operated On High-Temperature Oxide-Ion Chemistry, Qiming Tang

Theses and Dissertations

Climate change caused by anthropogenic greenhouse gas (GHG) emissions such as the burning of fossil fuels for power generation and industrial processing is affecting the global climate. To address this critical issue, a transition from fossil energy to renewable energy, especially wind and solar, is necessary. However, to successfully realize this transition, a cost-effective and large-scale stationary electricity storage system is indispensable. In this work, a new type of solid-oxide iron-air battery (SOIAB) operated on high-temperature oxide-ion chemistry is studied for this purpose due to its unique cycling characteristics suitable for large-scale Long Duration Electricity Storage (LDES) applications.

In the …

On Providing Efficient Real-Time Solutions To Motion Planning Problems Of High Complexity, Marios Xanthidis

Theses and Dissertations

The holy grail of robotics is producing robotic systems capable of efficiently executing all the tasks that are hard, or even impossible, for humans. Humans, undoubtedly, from both a hardware and software perspective, are extremely complex systems capable of executing many complicated tasks. Thus, the complexity of many state-of-the-art robotic systems is also expected to progressively increase, with the goal to match or even surpass human abilities. Recent developments have emphasized mostly hardware, providing highly complex robots with exceptional capabilities. On the other hand, they have illustrated that one important bottleneck of realizing such systems as a common reality is …

Highly Active And Stable Low-Pgm And Pgm-Free Catalysts For Anion Exchange Membrane Fuel Cells, Horie Adabi Firouzjaie

Theses and Dissertations

Anion exchange membrane fuel cells (AEMFCs) have recently seen significant growth in interest as their achievable current density, peak power density, and longevity have been dramatically improved. Though these advances in performance have been important for demonstrating the feasibility of the technology, nearly all AEMFCs reported in the literature have required a relatively high loading of platinum group metal (PGM)- based catalysts at both the anode and cathode electrodes. However, to take command of the low-temperature fuel cell market, AEMFCs cannot simply reach the same performance as incumbent proton exchange membrane fuel cells (PEMFCs), which have had decades of development …

Characterization Of Nonequilibrium Plasma Discharge In High Water Vapor Concentration, Malik Mohammad Tahiyat

Theses and Dissertations

In recent years, plasma discharge in liquid medium has been a topic of immense interest. Theoretical efforts have been pursued to obtain insight on physicochemical processes being influenced due to trace water vapor either being present as residual or provided at a known concentration. However, studies on discharge at high vapor content are limited. In this study, discharge characteristics of plasma in high water concentration (> 90%) are investigated experimentally for a pressure range of 1 – 15 Torr to maximize vapor loading without condensation. Voltage-current characteristics were obtained over 0- 14 mA of current for each operating pressure; current …

On The Influence Of Afp-Induced Defects On Mechanical Behavior Of Composite Laminates Under Fatigue Loading, Pierre Chevalier

Theses and Dissertations

The objective of the work presented in this thesis is to propose and validate a numerical solution to quantify the influence of Automated Fiber Placement (AFP) induced defects on the mechanical behavior of conventional composite laminates in fatigue. The work presented here will be divided in six sections. At first, a description of the Automated Fiber Placement process and its associated defects is proposed. In association, two tools developed for a rapid analysis and a progressive damage analysis respectively are discussed and used as an introduction to the work conducted in this thesis. In the second section, an extensive literature …

Observing And Modeling Water Electrolysis Performance Limitations Attributed To Gas Generation And Porous Media Properties, Joseph S. Lopata

Theses and Dissertations

Water electrolysis has been a simple method of hydrogen production for over two centuries, but the exploration of its nuances is still accelerating. This work compiles numerous mechanisms via which electrolysis efficiency is influenced by phenomena that occur within, adjacent to, and nearby functional porous media. Computational and experimental methods are applied to electrolysis systems to quantify the impact of twophase flow patterns and porous media properties on energy losses, primarily those linked directly to the presence of the gas phase.

First, an introduction to the chemistry and operating principle of water electrolysis is presented and relevant works from the …

Rational Synthesis Of Ultra-Small And Durable Platinum-Based Catalysts For Renewable Energy Applications, Fahim Bin Abdur Rahman

Theses and Dissertations

Ultrasmall supported platinum nanoparticles (Pt NPs) are often used in two promising renewable energy production technologies – hybrid-sulfur water splitting for actively catalyzing H2SO4 decomposition and in fuel cells for the oxygen reduction reaction (ORR). However, the stability of Pt NPs under reaction conditions is the ultimate challenge for these processes. Two prevalent ways to overcome this challenge are improving stability by anchoring Pt onto a secondary metal or doping heteroatoms into the support. This dissertation covers the rational design, synthesis, and stabilization of Pt-based catalysts in these two ways to achieve durable catalytic performance with desired activity and selectivity. …

Upper Regime Bedform Geometries And Types As A Function Of Sediment Supply And Grain Size, Sydney Sanders

Theses and Dissertations

Most research on fluvial bedforms focuses on the study of dunes (lower regime), and much less is known on upper regime bedforms. Studying upper regime bedforms, the conditions in which they form and how the geometry changes with flow and sediment properties is necessary for interpreting the stratigraphic record, estimate flow resistance and reconstruct flow characteristics from observed geometries. Here I present results of laboratory experiments designed to investigate the role of suspended bed material and sediment grain size on upper regime bedforms. Experiments were performed in open channel flow mode in a sediment-feed flume with a 0.19 m wide, …