Engineering Commons^™

Earth Abundant Thin Film Technology For Next Generation Photovoltaic Modules, Githin Alapatt

All Dissertations

With a cumulative generation capacity of over 100 GW, Photovoltaics (PV) technology is uniquely poised to become increasingly popular in the coming decades. Although, several breakthroughs have propelled PV technology, it accounts for only less than 1% of the energy produced worldwide. This aspect of the PV technology is primarily due to the somewhat high cost per watt, which is dependent on the efficiency of the PV cells as well as the cost of manufacturing and installing them. Currently, the efficiency of the PV conversion process is limited to about 25% for commercial terrestrial cells; improving this efficiency can increase …

Steps Toward A Net-Zero Campus With Renewable Energy Resources, Andrew Clarke

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With the increasing attention and support behind plug in hybrid electric vehicles, research must be conducted to examine the impacts of vehicles on electric distribution and transmission systems. This research aims first to model the behavior of vehicle battery chargers during system disturbances and mitigate any impacts. A distribution test system example is modeled and several different vehicle charger topologies are added. Faults are applied to the distribution system with vehicle chargers connected and the results are examined. Based on these results, a control strategy to mitigate their negative impacts is suggested. Photovoltaic panels are then added to the system …

Autonomous Control And Automotive Simulator Based Driver Training Methodologies For Vehicle Run-Off-Road And Recovery Events, Paul Freeman

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Traffic fatalities and injuries continue to demand the attention of researchers and governments across the world as they remain significant factors in public health and safety. Enhanced legislature along with vehicle and roadway technology has helped to reduce the impact of traffic crashes in many scenarios. However, one specifically troublesome area of traffic safety, which persists, is run-off-road (ROR) where a vehicle's wheels leave the paved portion of the roadway and begin traveling on the shoulder or side of the road. Large percentages of fatal and injury traffic crashes are attributable to ROR. One of the most critical reasons why …

The Development And Characterization Of Tannic Acid Cross-Linked Collagen Scaffolds For The Prevention Of Breast Cancer Recurrence In Lumpectomy Patients, Beau Inskeep

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Breast cancer is the second most common cancer amongst women, second only to lung cancer. In 2014, it was estimated that there were approximately 295,000 new cases of breast cancer diagnosed in women, with approximately 40,000 deaths caused by breast cancer in the United States. It has been reported that a woman has a 12% chance of developing breast cancer in her lifetime and a 3% chance of dying from breast cancer. There are several treatment options available for breast cancer, including chemotherapy, radiation therapy, as well as two different forms of surgery, mastectomy and lumpectomy. However, none of these …

Thermo-Mechanical Characterization Of Glass And Its Effect On Predictions Of Stress State, Birefringence And Fracture In Precision Glass Molded Lenses, Dhananjay Joshi

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The Precision Glass Molding (PGM) process was established as an economical and sustainable option for the production of aspherical glass optics to satisfy the increased industrial demand. Applications of precision molded aspherical lenses range from consumer electronics products such as cell phone cameras to defense and medical systems. An aspherical lens can eliminate the spherical and optical aberrations as compared to a spherical lens thus making the lens system more compact and lighter. In spite of being a clean and environmentally friendly process, the lens molding operation suffers from a few drawbacks such as lens profile deviation, stress birefringence/refractive index …

Robust Geotechnical Design - Methodology And Applications, Lei Wang

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This dissertation is aimed at developing a novel robust geotechnical design methodology and demonstrating this methodology for the design of geotechnical systems. The goal of a robust design is to make the response of a system insensitive to, or robust against, the variation of uncertain geotechnical parameters (termed noise factors in the context of robust design) by carefully adjusting design parameters (those that can be controlled by the designer such as geometry of the design). Through an extensive investigation, a robust geotechnical design methodology that considers explicitly safety, robustness, and cost is developed. Various robustness measures are considered in this …

Effects Of Transportation Hazards On Package Performance And Food Product Shelf Life, Kyle Dunno

All Dissertations

This research studied the effect of transportation hazards on food product shelf life and package performance. Studies were conducted to determine the effect of package headspace volume, product viscosity and storage temperature on package integrity. Finally, accelerated shelf life testing (ASLT) was utilized to determine how simulated transportation hazards affected the shelf life of a specific food product. Institutional retort pouches containing either water or 5% starch solution were filled with varying amounts of headspace volume to determine if package headspace volume could aid in package performance during simulated engineering tests for packaged products. Fixed displacement vibration testing and compression …

Estimating Field At-Rest Lateral Stress Coefficient And Liquefaction Resistance Of Aged Sands, Md Hossian

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Published results of laboratory tests to evaluate the influence of the at-rest lateral stress coefficient (K0) and the overconsoildation ratio (OCR) on liquefaction resistance of sands are reviewed in this dissertation. It is found that significant increase in liquefaction resistance can occur with high K0 and/or high OCR. A unique relationship between liquefaction resistance of isotropic and anisotropic normally consolidated sands exists based on the published laboratory data. Relationships between liquefaction resistance of overconsolidated sands and normally consolidated sands also have been shown in previous laboratory studies. Based on the previous studies, expressions for K0 and OCR correction factors (KK0 …

Robust Design Of Shield Tunnels ‒ Considering The Longitudinal Variation Of Input Parameters, Wenping Gong

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This dissertation, aimed at developing an improved design methodology for shield tunnels that explicitly considers design robustness against longitudinal variation of input parameters (such as soil parameters). To this end, a new solution model for shield tunnel performance analysis was first developed. In this new model, the random field concept was employed to model the longitudinal variation of input parameters. The input parameters (in the longitudinal domain) that had been generated with Monte Carlo simulation (MCS) were used as inputs for the tunnel longitudinal behavior analysis. Here, the finite element method (FEM) based upon Winkler elastic foundation theory was employed. …

Nonequilibrium Transport Of Ionic Liquids In Electrified Nanosystems, Xikai Jiang

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Room-temperature ionic liquids (RTILs) are a promising class of electrolyte that are composed entirely of ions but are liquid at room temperature. Their remarkable properties such as wide electrochemical window make them ideal electrolytes in many electrochemical systems. Because the non-equilibrium transport of RTILs often determines the performance of these systems, a fundamental understanding of such transport is needed. Here, using molecular dynamic (MD) and continuum simulations, we investigated the non-equilibrium transport of RTILs in three scenarios relevant to the application of RTILs in electrochemical systems: the electroosmotic flow (EOF) of RTILs through nanochannels, the electrokinetic transport of RTILs through …

Particle Scavenging By Water Drops In An Ultrasonic Standing Wave Field, Weiyu Ran

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Currently the backbone of the world's energy supply is composed of fossil fuels. However, the combustion of fossil fuels results in the production of enormous quantities of particulate pollutants. The smog resulting from these particulate pollutants causes significant health problem for city dwellers. Wet scrubbers, which use a water spray to scavenge airborne particles, is one of the most widely used devices to control particulate pollutants. Typical wet scrubbers can scavenge particles with diameters bigger than 10 um, but it is inefficient in scavenging particles with diameters on the order of 1 um. Unfortunately these fine particles are more dangerous …

High Frequency Devices And Circuit Modules For Biochemical Microsystems, Jiwei Sun

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This dissertation investigates high frequency devices and circuit modules for biochemical microsystems. These modules are designed towards replacing external bulky laboratory instruments and integrating with biochemical microsystems to generate and analyze signals in frequency and time domain. The first is a charge pump circuit with modified triple well diodes, which is used as an on-chip power supply. The second is an on-chip pulse generation circuit to generate high voltage short pulses. It includes a pulse-forming-line (PFL) based pulse generation circuit, a Marx generator and a Blumlein generator. The third is a six-port circuit based on four quadrature hybrids with 2.0~6.0 …

A Comprehensive Assessment Methodology Based On Life Cycle Analysis For On-Board Photovoltaic Solar Modules In Vehicles, Mahmoud Abdelhamid

All Dissertations

This dissertation presents a novel comprehensive assessment methodology for using on-board photovoltaic (PV) solar technologies in vehicle applications. A well-to-wheels life cycle analysis based on a unique energy, greenhouse gas (GHG) emission, and economic perspective is carried out in the context of meeting corporate average fuel economy (CAFE) standards through 2025 along with providing an alternative energy path for the purpose of sustainable transportation. The study includes 14 different vehicles, 3 different travel patterns, in 12 U.S. states and 16 nations using 19 different cost analysis scenarios for determining the challenges and benefits of using on-board photovoltaic (PV) solar technologies …

Thermally Responsive Polymer Electrolytes For Inherently Safe Electrochemical Energy Storage, Jesse Kelly

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Electrochemical double layer capacitors (EDLCs), supercapacitors and Li-ion batteries have emerged as premier candidates to meet the rising demands in energy storage; however, such systems are limited by thermal hazards, thermal runaway, fires and explosions, all of which become increasingly more dangerous in large-format devices. To prevent such scenarios, thermally-responsive polymer electrolytes (RPEs) that alter properties in electrochemical energy storage devices were designed and tested. These RPEs will be used to limit or halt device operation when temperatures increase beyond a predetermined threshold, therefore limiting further heating. The development of these responsive systems will offer an inherent safety mechanism in …

Development Of An In Vitro Three-Dimensional Breast Tissue Model To Decipher The Effects Of Stromal Heterogeneity On Normal And Cancerous Mammary Epithelial Cells, Erin Mccave

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A goal of breast cancer research is to develop a detailed understanding of the underlying mechanisms of disease progression and to generate approaches to improve early detection, monitoring, and treatment of breast cancerous lesions. Current breast cancer therapies are not successful for all cases as they were developed as a standard of care for 'average' breast cancer condition. To further current clinical success, the characteristics of each tumor mass must be considered. Such an individualized or personalized approach is incompatible with current understanding of 'average' breast cancer tumors and responses to treatments. The long-term objective of the present research is …

Modeling Sustainability In Renewable Energy Supply Chain Systems, Fei Xie

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This dissertation aims at modeling sustainability of renewable fuel supply chain systems against emerging challenges. In particular, the dissertation focuses on the biofuel supply chain system design, and manages to develop advanced modeling framework and corresponding solution methods in tackling challenges in sustaining biofuel supply chain systems. These challenges include: (1) to integrate 'environmental thinking' into the long-term biofuel supply chain planning; (2) to adopt multimodal transportation to mitigate seasonality in biofuel supply chain operations; (3) to provide strategies in hedging against uncertainty from conversion technology; and (4) to develop methodologies in long-term sequential planning of the biofuel supply chain …

Development Of A Transport System For Advancing Tissue Engineering And Cell Identification, Suzanne Mae Tabbaa

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This work centers on the development of a novel passive transport system for two tissue engineering applications – cell distribution and cell separation. This approach relies on a wicking fiber-based system, derived from the textile field that functions by directing and maintaining transport of cells as well as fluids and biomolecules. This system has the ability to enhance cell movement for both the purpose of cell seeding distribution as well as to isolate specific cell types from heterogeneous cell populations.

The success of spinal fusions and large bone defects is often limited by the decreased surrounding vasculature and the ability …

Inlay Vs. Onlay: A Comparison Of Two Glenoid Systems In Total Shoulder Arthroplasty, Sarah Helms

All Theses

Loosening of the glenoid component via a 'rocking horse' phenomenon, whereby the glenoid loosens as a result of edge loading of the implant during mild off-axis motion, is a common complication of total shoulder arthroplasties (TSAs). Recently, a partial glenoid resurfacing implant, known as a glenoid inlay, has become available and due to its geometry has the potential to exhibit less rocking-horse loosening during humeral articulation than the standard glenoid onlay systems currently used in TSA. The inlay design is implanted centrally on the glenoid to match the surrounding anatomy with a fit that leaves it flush with the surrounding …

A Study Of The Regularity Of Autocorrelation Of Manipulation Of Wrist Motion During Eating, Xueting Yu

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This thesis considers the problem of detecting the eating activities (e.g. meals, snacks) of people by tracking their wrist motion. Our goal is to automatically de- tect the start and end times of eating activities during free-living. It builds upon previous work done by our research group [6] [7] [8] [21]. The detection is done by segmenting data into segments then classifying the segments as EA (eating activity) and NonEA (non-eating activity) using a Bayesian classier. Previous features used in the classier developed by our group included the sum of acceleration, the amount of manipulation, the amount of wrist roll …

The Effects Of Chlorine Dioxide Gas On The Sensory Properties Of Whole Tomatoes, Christopher Gottilla

All Theses

This experiment sought to measure the changes in sensory quality that occur in tomatoes as the result of chlorine dioxide gas treatment. Tasti-Lee tomatoes (VFFF Hybrid #5755) were treated with two different levels of chlorine dioxide gas (10mg and 50mg of ClO2-forming material per kg of tomato) utilizing sachets. Testing compared the treated tomatoes and an untreated control group. These tests included flat-plate compression for firmness, sensory evaluation using a difference from control test, color analysis of the skin and flesh using a colorimeter, and enumeration of aerobic microbes and yeasts and molds. Flat-plate compression of whole tomatoes revealed no …

Combining Modified Atmosphere Packaging And Nisin To Extend The Shelf Life Of Atlantic Salmon (Salmo Salar), Dong Han

All Theses

Atlantic salmon is often used in laboratory experiments to represent marine fishes. Many researchers try to optimize the levels and dosage of preservatives to maintain the freshness and extend the shelf-life of Atlantic salmon. Little information has been provided about the effectiveness of combined method between MAP and nisin, especially on the preservation of Atlantic salmon. Strong evidences suggest that MAP associated with nisin may have a potential to improve Atlantic salmon storage quality. Preservation effectiveness of combining modified atmosphere package (MAP) and nisin on fresh Atlantic salmon was determined using various methods. Six groups of farmed Atlantic salmon were …

Scientific Application Acceleration Utilizing Heterogeneous Architectures, Edwin Weill

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Within the past decade, there have been substantial leaps in computer architectures to exploit the parallelism that is inherently present in many applications. The scientific community has benefited from the emergence of not only multi-core processors, but also other, less traditional architectures including general purpose graphical processing units (GPGPUs), field programmable gate arrays (FPGAs), and Intel's many integrated cores (MICs) architecture (i.e. Xeon Phi). The popularity of the GPGPU has increased rapidly because of their ability to perform massive amounts of parallel computation quickly and at low cost with an ease of programmability. Also, with the addition of high-level programming …

Optimizing Light Collection From Extractive Scintillating Resin In Flow-Cell Detectors, Amy Meldrum

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The objectives of this study were to investigate the changes in light collection efficiency for flow cell detector as various parameters are altered to find the optimum flow cell configuration. Columns with inner diameters of 0.16 cm, 0.48 cm, 0.79 cm, and 1.11 cm were packed with synthesized nonporous, un-functionalized beads to measure their detection efficiencies for solutions containing 210Po, 14C, or 90Sr/90Y. The average diameter of the beads used in the experiments was 147 µm ± 33 µm. The highest detection efficiency for 210Po was 15.3 ± 3.9% with the 1.11 cm diameter column. The 1.11 cm diameter column …

Using Gis To Prioritize Green Infrastructure Installation Strategies In An Urban Watershed, Lauren Owen

All Theses

This study seeks to quantify runoff volume generation and peak flow rates from the urban Sand River Headwaters to determine the most effective placement of additional green infrastructure in Aiken, SC. ArcMap 10.1, HEC-GeoHMS, and HEC-HMS were used to delineate a total outlet watershed along with subwatershed(s) for urban stormwater infrastructure system by 'burning' the stormwater system at an artificial elevation below the existing topologically-based Digital Elevation Model (DEM). The result was a higher resolution DEM that allowed for storm routing and subsequent volume and flow predictions compared to that based on the original DEM created by using Light Detecting …

Fabrication And Characterization Of Magnetic Nanoparticle Composite Membranes, Akeem Cruickshank

All Theses

To effectively and accurately deliver drugs within the human body, both new designs and components for implantable micropumps are being studied. Designs must ensure high biocompatibility, drug compatibility, accuracy and small power consumption. The focus of this thesis was to fabricate a prototype magnetic nanoparticle membrane for eventual incorporation into a biomedical pump and then determine the relationship between this membrane deflection and applied pneumatic or magnetic force. The magnetic nanoparticle polymer composite (MNPC) membranes in this study were composed of crosslinked polydimethylsiloxane (PDMS) and iron oxide nanoparticles (IONPs). An optimal iron oxide fabrication route was identified and particle size …

Geotechnical Analysis Of The Foundation Of Fort Sumter National Monument Using Numerical Modeling, Daniel Kyser

All Theses

The foundational condition of the historical coastal fortification of Fort Sumter in Charleston, SC was analyzed though the use of numerical modeling. In this study, two-dimensional Finite Element (FE) analyses were conducted to assess the stability of the foundation-casemates-wall system in a coupled manner subjected to potential loadings such as ocean waves, storm surge and earthquake. The finite element model was verified by modeling the historical events (construction between 1820 and 1860, demolition due to artillery bombardment, reconstruction, earthquake, building of the Battery Huger, and the removal of fill from the parade ground) since the construction of the fort in …

A Device To Record Naturally Daily Wrist Motion, Surya Sharma

All Theses

We introduce a new device to record and store wrist motion activity data. The motivation to create this device was the fact that this data can be used to detect periods of eating or the number of bites consumed. There is no similar device available in the market. This device uses new components that have been recently introduced to the market, and newer techniques that can be used for low quantity production. The production cost for this device was $52, similar to other fitness trackers on the market. The device was capable of recording wrist motion activity for 24 hours …

Characterizing Navigational Tools In A Virtual Search Task, Austin Riggs

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The goal of this thesis is to characterize and empirically compare navigational tools in the context of a virtual inspection task. The framework considers both directional-cue navigational tools (e.g., GPS navigation arrows) and trail navigational tools (e.g.,footprints) in comparison to a control condition. Characterizing the tools allows for documented relationships between specific navigational tool-performance combinations. It is intended that by characterizing and comparing the tools a more advantageous use of navigational tools will emerge to increase the benefit provided to both the users and implementers of virtual environments. The focus of the metrics in the paper were distance traveled, speed …

Design, Analysis And Implementation Of An Experimental System To Harvest Energy From Atmospheric Temperature Variations Using Ethyl Chloride Filled Bellows, Gibran Ali

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The increase in global warming and the dwindling supplies of fossil fuels have shifted the focus from traditional to alternate sources of energy. This has resulted in a concerted effort towards finding new energy sources as well as better understanding traditional renewable energy sources such as wind and solar power. In addition to the shift in focus towards alternate energy, the last two decades have offered a dramatic rise in the use of digital technologies such as wireless sensor networks that require small but isolated power supplies. Energy harvesting, a method to gather energy from ambient sources including sunlight, vibrations, …

Microanalysis Of Polymer Chain Diffusion In Heat Seals, Russell Cooper

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Heat sealing is an integral method for the closure and protection of packaging. Previous work has shown that seal strength is developed by the interdiffusion of polymer chains within heat seals. Heat seals were made between two dissimilar materials. Poly(ethylene-co-acrylic acid) (EAA) was heat sealed to ionomer. Diffusion within the EAA-ionomer heat seals was estimated. The diffusion estimates were then related to resulting seal strength in the EAA-ionomer sealant system. Heated tooling sealing was utilized to make heat seals at 40 psi (275.79 kPa), 0.5 seconds, and a range of temperatures between 180˚F (82.22˚C) and 300˚F (148.89˚C). Scanning electron microscopy …