Engineering Commons^™

Algorithmic Robot Design: Label Maps, Procrustean Graphs, And The Boundary Of Non-Destructiveness, Shervin Ghasemlou

Theses and Dissertations

This dissertation is focused on the problem of algorithmic robot design. The process of designing a robot or a team of robots that can reliably accomplish a task in an environment requires several key elements. How the problem is formulated can play a big role in the design process. The ability of the model to correctly reflect the environment, the events, and different pieces of the problem is crucial. Another key element is the ability of the model to show the relationship between different designs of a single system. These two elements can enable design algorithms to navigate through the …

The Hybridization Of A Graphene And Silicon Carbide Schottky Optoelectronic Device By The Incorporation Of A Lead Sulfide Quantum Dot Film, Joshua Letton

Theses and Dissertations

The work that follows examines the impact of lead sulfide quantum dots on a native epitaxial graphene (EG) SiC Schottky device, resulting in a hybrid optoelectronic device which presents a possible avenue towards a novel hybrid carbide-based Schottky solar cell. The active (n-type SiC) and contact (graphene) layers for the Schottky junction of the device were grown epitaxially using a novel technique incorporating tetrafluorosilane (TFS) as a precursor gas. The bare EG/SiC device was characterized based on its I-V behavior in dark and under illumination for both forward and reverse bias conditions. The initial characterization demonstrated the expected Schottky diode …

Fundamental Studies Of Oxygen Electrocatalysis In Alkaline Electrochemical Cells, Victoria F. Mattick

Theses and Dissertations

Until recently the world’s main source of energy has been fossil fuels, such as coal and petroleum. However, these energy sources are polluting our planet, becoming scarce and increasingly inaccessible, and are costly to extract. Therefore, much attention has been directed to harvesting clean, abundant, and renewable energy, such as solar rays and wind. However, the intermittency of solar and wind power generation requires an effective energy buffering solution (aka energy storage) to become efficient and reliable. With high efficiency and energy density, rechargeable batteries and reversible fuel cells are two of the best methods for this purpose. Unfortunately, a …

Cis-Resveratrol Upregulates Tyrosyl-Trna Synthetase And Inhibits The Proliferation Of Select Breast Cancer Cell Lines, Marion Cone Hope Iii

Theses and Dissertations

Breast cancer is one of the most commonly occurring cancers in women. 70% of breast cancer patients express ERα and are treated with tamoxifen (Tam), a drug that is used to directly target ERα. However, 20-30% of cancer patients develop a resistance to Tam. This resistance leads to a worse prognosis and other treatments such as DNA damaging drugs or radiation to eliminate these cells. Resveratrol (RSV) is a polyphenolic- compound found in plants such as grapes and hellebore and is known to evoke anti-cancer effects. While natural resveratrol exists as a mixture of both cis- and trans- isomers, so …

17 Β-Estradiol And Phytoestrogens Attenuate Apoptotic Cell Death In Hiv-1 Tat Exposed Primary Cortical Cultures, Sheila Marie Adams

Theses and Dissertations

Despite the advent of highly active antiretroviral therapy (HAART), neurological disorders develop in most people infected with human immunodeficiency virus type 1 (HIV-1). The poor CNS delivery of anti-retrovirals allows continued virus production and renders neurons susceptible to the toxic effects of released viral proteins. The neurotoxic potential of HIV-1 viral protein Tat has been shown to include excitotoxicity, oxidative stress, and mitochondrial dysfunction leading to subsequent cell death. Thus, Tat is thought to have a key role in the pathogenesis of HIV-associated neurodegeneration. Estrogens are universally considered to be neuroprotective, as such; estrogens have positive implications in the treatment …

Solid Materials Discovery For Thin Films, Oxide Catalysts, And Polymer Sealants, Benjamin Ruiz-Yi

Theses and Dissertations

Solid materials are made up of multiple classes, including metals, ceramics, and polymers. While each class can be developed for general purpose applications or highly specialized, discovery of new materials in order to improve upon desired properties is a non-trivial task for any type of material. A wide variety of materials encompass expansive design spaces, consisting of parameters such as chemical compositions, synthesis conditions, and post-processing. Due to this, narrowing down the design space to fit within a given figure-of-merit and economic viability becomes time consuming at best and infeasible at worst. High-throughput experimentation

High-throughput experimentation (HTE) is a methodology …

On The Robustness Of Bayesian Network Learning Algorithms Against Malicious Attacks, Noah Joseph Geveke

Theses and Dissertations

Bayesian networks are effective tools for discovering relationships between variables in a data set. Algorithms that learn Bayesian networks from data fall into three categories: constraint-based, score-based, and hybrid. Hybrid algorithms contain a constraint testing sub-procedure as well as a score function to create the network. Malicious changes to the training set can cause invalid networks that do not model the true data. The effects of these changes have been demonstrated using the PC algorithm, a constraint-based algorithm. In this thesis a method was developed to measure the robustness of various algorithms to determine potential malicious changes. The robustness analysis …

Novel Multi-User Chirp Signaling Schemes For Future Aviation Communication Applications, Nozhan Hosseini

Theses and Dissertations

Many wireless communication systems will need to accommodate a larger number of users in the future. One application in particular in which this is critical is low data rate, long range communication links with very large numbers of nodes, such as the internet of things (IoT), possibly the internet of flying things (IoFT), etc. These systems demand advanced multi-access techniques with minimal multiple access interference (MAI). They should also be robust to multiple impairments, including multipath channel distortions, Doppler spreading, and interference. Chirp waveforms are one type of waveform set that can satisfy future system demands in the presence of …

Room Temperature Semiconductor Radiation Detectors Based On Cdznte And Cdzntese, Mohsin Sajjad

Theses and Dissertations

In recent years, there have been considerable interests in nuclear radiation detectors for national security and nuclear safeguard including monitoring special nuclear materials and nuclear waste characterization, for medical imaging devices using nuclear medicine such as positron emission tomography (PET), and for NASA space astronomy. One of the most promising semiconductors being considered for the field-deployable nuclear detector is cadmium zinc telluride (CdZnTe or CZT). CZT is a ternary semiconductor that can efficiently stop and detect high-energy gamma-rays at room temperature. CZT has desirable properties for efficient nuclear radiation detection and imaging due to high atomic number (Z ~ 50, …

Enhancing Single And Two-Phase Heat Transfer Of Microgap Heat Sinks Using Nano-Structure Coatings, Yueyang Zhao

Theses and Dissertations

Due to the shrinking size and increasing power of electronics, the heat flux generated by electronic devices has greatly increased and imposed challenges to thermal management technologies. Numerous cooling technologies have been developed to cool high-power electronics. Among them, flow boiling in microchannels or a microgap has been one of the most efficient ways to remove high heat flux, which requires less coolant compared with single-phase cooling techniques. However, the flow boiling instability is the one of the most challenging issues, which lead to the premature critical heat flux (CHF) conditions and deteriorate heat transfer rate. The capillary force generated …

Design Of High Efficiency Wireless Power Thansfer System With Nonlinear Resonator, Yibing Zhang

Theses and Dissertations

Wireless power transfer technology (WPT) has been rapidly developed in recent years. The primary benefit of WPT is that it replaces the traditional wire charging with a cordless charging method. WPT technology has been applied in many fields, such as bio-implants, electric vehicles, and wirelessly charging systems. According to the different energy transmission mechanism, WPT technology can be divided into magnetic field coupling (includes magnetically coupled inductive and magnetically-coupled resonant), microwave radiation, laser emission, electrical-field coupling, and ultrasonic transmission type. Among these technologies, the magnetic resonance coupling method has a better promise because of its long transfer distance and high …

Guided-Wave Shm And Nde Of Composite Structures: Modeling And Experiments, Hanfei Mei

Theses and Dissertations

The extensive use of composites in aerospace structures has posed new challenges for implementing effective structural health monitoring (SHM) and nondestructive evaluation (NDE) techniques due to the general anisotropic behavior and complex damage scenarios in composites. This dissertation addresses the SHM and NDE of composites using ultrasonic guided waves, with an emphasis on theoretical modeling and experimental validation of guided-wave propagation and interaction with damage in composites. A semi-analytical finite element (SAFE) approach is presented to calculate guided-wave dispersion curves in composites. The theoretical framework is formulated using the finite element method (FEM) to describe the material variation along the …

Investigation Of Oxidized Carbon Supported Au Catalysts Synthesized Via Strong Electrostatic Adsorption Of Au(En)2Cl3 For The Hydrochlorination Of Acetylene To Vinyl Chloride Monomer, Sean Reginald Noble

Theses and Dissertations

Over 20 million tons of vinyl chloride monomer (VCM) is produced every year using acetylene hydrochlorination using a supported mercuric chloride catalyst. During this process mercury is reduced and sublimes into the environment harming all living animals and humans, so carbon-supported Au catalysts have been developed in attempts to replace it. Various techniques have been used to make these catalysts including several variations of dry impregnation. In this study we investigate the ability of Strong Electrostatic Adsorption (SEA) of Au(en)₂Cl₃ onto various supports to demonstrate the ability to rationally and consistently synthesize gold catalysts with ultra-small particle …

Theoretical Investigation Of The Biomass Conversion On Transition Metal Surfaces Based On Density Functional Theory Calculations And Machine Learning, Wenqiang Yang

Theses and Dissertations

During the past decades, heterogenous catalyzed conversion of biomass to hydrocarbons with similar or identical properties to conventional fossil fuels has gained significantly academic and industrial interest. However, the conventional heterogeneous catalysts such as sulfided NiMo/Al₂O₃ and CoMo/Al₂O₃ used have various drawbacks, such as short catalyst lifetime and high sulfur content of product. To overcome the limitations of the conventional sulfided catalysts, new catalysts must be developed, which requires a better understanding of the reaction mechanism of the biomass conversion. Based on density functional theory, in this thesis, we reported a computational calculation study …

Fundamental Understanding Of Plasma Discharge Formation In Liquid And Multiphase Configurations Through Multiphysics Modeling, Ali Charchi Aghdam

Theses and Dissertations

During the last two decades, non-thermal plasma discharges in and in contact with liquids have received significant attention due to their wide range of applications including chemical analysis, medical, water treatment, fuel processing, etc. Despite the tremendous interest and advances attained in the experimental studies, modeling efforts providing a comprehensive understanding of the underlying physicochemical processes are limited. There is still no unified theory on plasma formation in dense medium and various theories have been proposed such as the presence of bubbles and tunneling which are topics of debate. In the first part of this study, a mathematical model is …

Evaluation Of Temporal Damage Progression In Concrete Structures Affected By Asr Using Data-Driven Methods, Vafa Soltangharaei

Theses and Dissertations

Alkali-silica reaction (ASR) is a chemical reaction, which causes damage in concrete structures such as bridges, dams, and nuclear containments and powerplant structures. The ASR-induced damage may endanger the integrity and serviceability of structures. Several methods such as visual inspection, petrographic analysis, demountable mechanical strain gauges, and cracking index have been utilized for study the effect of ASR on structures, which are not always efficient in early damage detection and some are destructive and prohibited in nuclear structures. Nondestructive methods and structural health monitoring techniques can be alternatives for the condition assessment of structures. Among the nondestructive methods, acoustic emission …

Introducing The Journal Of Nuclear Engineering: An Interdisciplinary Open Access Journal Dedicated To Publishing Research In Nuclear And Radiation Sciences And Applications, Dan Gabriel Cacuci

Faculty Publications

Note: In lieu of an abstract, this is an excerpt from the first page.

In 1938, Strassmann, Hahn and Meitner discovered neutron-induced nuclear fission in uranium, forever changing our world and opening multiple paths to developing nuclear energy, nuclear medicine, instrumentation, space propulsion, environmental monitoring, remediation and nuclear security [...]

Fatigue-Crack Detection And Monitoring Through The Scattered-Wave Two-Dimensional Cross-Correlation Imaging Method Using Piezoelectric Transducers, Wenfeng Xiao, Lingyu Yu, Roshan Joseph, Victor Giurgiutiu

Faculty Publications

Piezoelectric transducers are convenient enablers for generating and receiving Lamb waves for damage detection. Fatigue cracks are one of the most common causes for the failure of metallic structures. Increasing emphasis on the integrity of critical structures creates an urgent need to monitor structures and to detect cracks at an early stage to prevent catastrophic failures. This paper presents a two-dimensional (2D) cross-correlation imaging technique that can not only detect a fatigue crack but can also precisely image the fatigue cracks in metallic structures. The imaging method was based on the cross-correlation algorithm that uses incident waves and the crack-scattered …

Comprehensive Second-Order Adjoint Sensitivity Analysis Methodology (2nd-Asam) Applied To A Subcritical Experimental Reactor Physics Benchmark: V. Computation Of Mixed 2nd-Order Sensitivities Involving Isotopic Number Densities, Ruixian Fang, Dan Gabriel Cacuci

Faculty Publications

This work applies the Second-Order Adjoint Sensitivity Analysis Methodology (2nd-ASAM) to compute the mixed 2nd-order sensitivities of a polyethylene-reflected plutonium (PERP) benchmark's leakage response with respect to the benchmark's imprecisely known isotopic number densities and the other benchmark imprecisely known parameters, including: (i) the 6 × 180 mixed 2nd-order sensitivities involving the total microscopic cross sections; (ii) the 6 × 21,600 mixed 2nd-order sensitivities involving the scattering microscopic cross sections; (iii) the 6 × 60 mixed 2nd-order sensitivities involving the fission microscopic cross sections; and (iv) the 6 × 60 mixed 2nd-order sensitivities involving the average number of neutrons produced …

Material Discovery And High Throughput Exploration Of Ru Based Catalysts For Low Temperature Ammonia Decomposition, Katherine Mccullough, Pei-Hua Chiang, Juan D. Jimenez, Jochen A. Lauterbach

Faculty Publications

High throughput experimentation has the capability to generate massive, multidimensional datasets, allowing for the discovery of novel catalytic materials. Here, we show the synthesis and catalytic screening of over 100 unique Ru-Metal-K based bimetallic catalysts for low temperature ammonia decomposition, with a Ru loading between 1–3 wt% Ru and a fixed K loading of 12 wt% K, supported on γ-Al2O3. Bimetallic catalysts containing Sc, Sr, Hf, Y, Mg, Zr, Ta, or Ca in addition to Ru were found to have excellent ammonia decomposition activity when compared to state-of-the-art catalysts in literature. Furthermore, the Ru content could be reduced to 1 …

Multimodal Mental Health Analysis In Social Media, Amir Hossein Yazdavar, Mohammad Saeid Mahdavinejad, Goonmeet Bajaj, William Romine, Amit P. Sheth, Amir Hassan Monadjemi, Krishnaprasad Thirunarayan, John M. Meddar, Annie Myers, Jyotishman Pathak, Pascal Hitzler

Publications

Depression is a major public health concern in the U.S. and globally. While successful early identification and treatment can lead to many positive health and behavioral outcomes, depression, remains undiagnosed, untreated or undertreated due to several reasons, including denial of the illness as well as cultural and social stigma. With the ubiquity of social media platforms, millions of people are now sharing their online persona by expressing their thoughts, moods, emotions, and even their daily struggles with mental health on social media. Unlike traditional observational cohort studies conducted through questionnaires and self-reported surveys, we explore the reliable detection of depressive …

Comprehensive Second-Order Adjoint Sensitivity Analysis Methodology (2nd-Asam) Applied To A Subcritical Experimental Reactor Physics Benchmark. Vi: Overall Impact Of 1st- And 2nd-Order Sensitivities On Response Uncertainties, Dan Gabriel Cacuci, Ruixian Fang, Jeffrey A. Favorite

Faculty Publications

: This work applies the Second-Order Adjoint Sensitivity Analysis Methodology (2nd-ASAM) to compute the 1st-order and unmixed 2nd-order sensitivities of a polyethylene-reflected plutonium (PERP) benchmark’s leakage response with respect to the benchmark’s imprecisely known isotopic number densities. The numerical results obtained for these sensitivities indicate that the 1st-order relative sensitivity to the isotopic number densities for the two fissionable isotopes have large values, which are comparable to, or larger than, the corresponding sensitivities for the total cross sections. Furthermore, several 2nd-order unmixed sensitivities for the isotopic number densities are significantly larger than the corresponding 1st-order ones. This work also presents …

Damage Evaluation Of Rolling Element Bearings For Shipboard Machinery, Brenna Lyn Feirer

Theses and Dissertations

Rolling element bearings perform an essential role in most all rotating machinery. To prevent degradation to machine performance, unforeseen costs and unexpected system failure, bearing fault diagnosis and prognosis are used. Acoustic Emission (AE) introduces high sensitivity, early and rapid detection of cracking, and real time monitoring that can alarm once cracking is noticed.

The purpose of this research is to nondestructively monitor the crack growth in rolling element bearings in a marine environment and to determine the acoustic emission parameters which embody crack initiation and propagation. The intellectual merit lies in:

1. the signal alarm developed from an AE …

Data-Driven Modeling Through Power Hardware In The Loop Experiments: A Pv Micro-Inverter Example, Hayder Dawood Abbood Almukhtar

Theses and Dissertations

The increasing penetration of wind turbines, photovoltaics (PV), fuel cells, microturbines, cogeneration, energy storage systems, and other Distributed Energy Resources (DER) presents both challenges and opportunities for distribution systems. A deep understanding of the characteristics of those devices, as well as accurate modeling, are essential to plan, design, and control modern distribution grids.

The objective of this research is to define data-driven modeling techniques that allow capitalizing on the results of Hardware In the Loop (HIL) and Power Hardware In the Loop (PHIL) testing by creating models of the devices under test (DUT) –also for closed-source, proprietary systems– using the …

Investigating The Effects Of Aggregate Size And Reinforcement On Asr Cracking In Concrete Structures Studied With Different Evaluation Methods, David Joseph Bianco

Theses and Dissertations

The objective of this thesis is to investigate different (non-destructive) evaluation methods to assess the effects of reactive aggregate size and reinforcement on ASR affected concrete. It has been shown in previous literature that reactive coarse aggregates lead to more expansion as opposed to reactive fine aggregates. However, there is a lack in the literature exhibiting this relationship using different evaluation methods, such as acoustic emission (AE) and ultrasonic pulse velocity (UPV). Also, the literature does not emphasize the role this relationship plays when the concrete is imposed with stress boundary conditions. Non-destructive test methods, including acoustic emission, are becoming …

Helicobacter’S Effects On Colitis/Colon Cancer And The Response To Indole 3-Carbinol, Rasha Raheem Abdulhamza Alkarkoushi

Theses and Dissertations

Enterohepatic Helicobacter (EHH) species are gram-negative bacteria, which are poorly studied. Several studies suggest that EHH species contribute to inflammatory bowel disease IBD in humans. IBD and colorectal cancer (CRC) has emerged as a public health challenge worldwide. Indole-3-carbinol (I3C) is one of the natural dietary indoles abundant in Brassica (cruciferous) vegetables. The aryl hydrocarbon receptor (AhR) plays an essential role as a regulator by controlling the balance between Tregs and Th17 cells. The activation of AhR by ligands derived from food or intestinal microbiota is an essential control mechanism in that balance. Moreover, many studies showed indoles achieving chemo-preventive …

Design And Testing Of A Supercritical Carbon Dioxide Plasma Reactor, Gregory Belk

Theses and Dissertations

The objective of this project was to design, build, and test a plasma reactor capable of operating in the supercritical conditions. The reactor allows for the initiation of a plasma discharge in different fluids driven by a direct current (DC) power supply operating either in steady state mode or pulsing mode. The reactor was specifically designed for igniting plasmas within supercritical carbon dioxide, which has a pressure of 72.9 atm and 31.1 degrees Celsius.

A series of runs were conducted for varying pressures and inter-electrode separation, which allowed testing the operation regimes of the reactors. Finally, plasma experiments were conducted …

The Use Of Natural Anthraquinone Emodin As A Primary And Complementary Therapeutic In The Treatment Of Colorectal Cancer, Alexander-Jacques Theodore Sougiannis

Theses and Dissertations

5 Fluorouracil (5FU) chemotherapy is widely used in the treatment of colorectal cancer (CRC), and has been the first-choice chemotherapy drug for CRC for many years. However, nearly 10% of patients receiving chemotherapy die during the first 30 days of treatment. Further, it is estimated that 70% of surviving patients will develop non-specific toxicities as a result of chemotherapy treatment. We characterize these toxicities in an animal model of chemotherapy treatment and show that perturbations in the gut microbiome might be exacerbate the prolonged effects of chemotherapy. A compound that could attenuate the multiple non-selective toxicities associated with chemotherapy could …

The Evolution Of The Southeastern North American Margin From Integrated Analyses Of Potential Field Data: Continent-Continent Collision And Rifting, Patrick D. Duff

Theses and Dissertations

The southeastern North American margin (SENAM) is one of the world’s oldest intact passive margins, containing the ancient southern Appalachian Mountains, the South Georgia Rift (SGR), and the Central Atlantic Magmatic Province (CAMP).

Potential field data is used in combination with seismic imaging, borehole data, and surface geology to better constrain the lithospheric configuration created by Appalachian orogenesis and Atlantic rifting. In combination with filtering techniques, maps and 2D potential field forward models, and Euler inverse modeling are used to illuminate the pre-Cretaceous basement including basement faults, shear zones, and granites in the hinterland of the southern Appalachians, and rift …

Design Of Bio-Inspired Multifrequency Acoustic Sensors And Metamaterial Energy Harvesting Smart Structures, Mohammadsadegh Saadatzi

Theses and Dissertations

Due to the limited availability and high depletion rates of nonrenewable sources of energy as well as environmental concerns, the scientific community has started to explore many alternative clean sources of energies. It is identified that civil, mechanical and Aerospace structures are always subjected to acoustic noises and vibration which could potentially be used as renewable source of energy. Roads and Industrial noise barriers are used inside industrial facilities alongside the walls, around construction pillars, nearby machinery and other equipment to separate quite work zones, protect walls, deliver extra safety and precautions while diminish sound and vibrational pressure. We hypothesized …