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Understanding The Nano- And Macroscale Processes Impacting Arsenic Mobilization During Managed Aquifer Recharge Using Reclaimed Wastewater, Chelsea Wren Neil

McKelvey School of Engineering Theses & Dissertations

Managed aquifer recharge (MAR) utilizing reclaimed wastewater is a vital means of replenishing natural freshwater supplies in order to meet growing demands. Unfortunately, this process has been found to induce unfavorable geochemical reactions which mobilize arsenic from aquifer sediments. This process is further complicated by the simultaneous formation of iron(III) (hydr)oxide secondary minerals, which can sorb aqueous arsenic. It is crucial to fully elucidate these physico-chemical processes in order to establish safe MAR operations which minimize arsenic release. Thus, the mechanisms controlling arsenic release from arsenopyrite during MAR were investigated from the nano- to macroscale.

First, nanoscale iron(III) (hydr)oxide nucleation …

Cyber-Physical Co-Design Of Wireless Control Systems, Bo Li

McKelvey School of Engineering Theses & Dissertations

Wireless sensor-actuator network (WSAN) technology is gaining rapid adoption in process industries because of its advantages in lowering deployment and maintenance cost in challenging environments. While early success of industrial WSANs has been recognized, significant potential remains in exploring WSANs as unified networks for industrial plants.

This thesis research explores a cyber-physical co-design approach to design wireless control systems. To enable holistic studies of wireless control systems, we have developed the Wireless Cyber-Physical Simulator (WCPS), an integrated co-simulation environment that integrates Simulink and our implementation of WSANs based on the industrial WirelessHART standard. We further develop novel WSAN protocols tailored …

Thermally Evolved & Separated Composition Of Atmospheric Aerosols: Development And Application Of Advanced Data Analysis Techniques For A Thermal Desorption Aerosol Gas Chromatograph (Tag), Yaping Zhang

McKelvey School of Engineering Theses & Dissertations

Atmospheric organic aerosols are composed of thousands of individual compounds, interacting with climate through changes in aerosol optical properties and cloud interactions, and can be detrimental to human health. Aerosol mass spectrometry (MS) and gas chromatography (GC)-separated MS measurements have been utilized to better characterize the chemical composition of this material that comes from a variety of sources and experiences continuous oxidation while in the atmosphere. This dissertation describes the development of a novel rapid data analysis method for grouping of major components within chromatography-separated measurements and first application using thermal desorption aerosol gas chromatograph (TAG) – MS data. Chromatograms …

Segmentation And Strain Mapping Of A Beating Heart, Kenna Middleton

McKelvey School of Engineering Theses & Dissertations

Conventional methods of estimating deformation optically often compare image intensities before and after deformation to help estimate the strain fields. However, these current meth ods often introduce undesirable error that propagates through the system, growing larger through each strain calculation. These errors create false, concentrated regions of strain throughout the image. Additionally, gathering and evaluating images in three- and four dimensional space creates even more difficulty for conventional methods. Here, by imple menting new techniques of gathering four-dimensional ultrasound data sets and calculating deformation fields with traditional errors reduced three-fold, four-dimensional images were evaluated to create a novel visualization tool …

Applying Bayesian Machine Learning Methods To Theoretical Surface Science, Shane Carr

McKelvey School of Engineering Theses & Dissertations

Machine learning is a rapidly evolving field in computer science with increasingly many applications to other domains. In this thesis, I present a Bayesian machine learning approach to solving a problem in theoretical surface science: calculating the preferred active site on a catalyst surface for a given adsorbate molecule. I formulate the problem as a low-dimensional objective function. I show how the objective function can be approximated into a certain confidence interval using just one iteration of the self-consistent field (SCF) loop in density functional theory (DFT). I then use Bayesian optimization to perform a global search for the solution. …

Measurement, Modeling, And Mitigation Of Lead Impacts From General Aviation, Stephen Neil Feinberg

McKelvey School of Engineering Theses & Dissertations

Airborne lead (Pb) has been regulated as a criteria pollutant by the United States Environmental Protection Agency (EPA) since the Clean Air Act and its amendments in the 1970s. During the 1970s, atmospheric Pb emissions were dominated by the combustion of leaded automobile fuel and metals manufacturing. Over time, those emissions have decreased greatly and according to the EPA the largest emitter of Pb today is piston-engine aircraft. Additionally, in 2008 the EPA reduced the National Ambient Air Quality Standard (NAAQS) for Pb by an order of magnitude. These combined factors served as the impetus for further study of general …

Optimization Of Looped Airfoil Wind Turbine (Lawt) And Looped Airfoil Hydro-Turbine (Laht) Design Parameters For Maximum Power Generation, Binhe Song

McKelvey School of Engineering Theses & Dissertations

This focus of this research is on the study of the aerodynamic performance of a Looped Airfoil Wind Turbine (LAWT™) using the Computational Fluid Dynamics (CFD) software. The looped airfoil wind turbine (LAWT™) is a patented new technology by EverLift Wind Technology, Inc. for generating power from wind. It takes advantage of the superior lift force of a linearly traveling wing compared to the rotating blades in conventional wind turbine configurations. Compared to horizontal and vertical axis wind turbines, the LAWT™ can be manufactured with minimal cost because it does not require complex gear systems and its blades have a …

Relating Neural Dynamics To Olfactory Coding And Behavior, Chao Li

McKelvey School of Engineering Theses & Dissertations

Sensory stimuli often evoke temporal patterns of spiking activity across a population of neurons in the early processing stages. What features of these spatiotemporal responses encode behaviorally relevant information, and how dynamic processing of sensory signals facilitates information processing are fundamental problems in sensory neuroscience that remain to be understood. In this thesis, I have investigated these issues using a relatively simple invertebrate model (locusts; Schistocerca americana).

In locusts, odorants are transduced into electrical signals by olfactory sensory neurons in the antenna and are subsequently relayed to the downstream neural circuit in the antennal lobe (analogous to the olfactory bulb …

Automating Intensity Modulated Radiation Therapy Treatment Planning By Using Hierarchical Optimization, Paras Babu Tiwari

McKelvey School of Engineering Theses & Dissertations

The intensity modulated radiation therapy (IMRT) optimizes the beam’s intensity to deliver the prescribed dose to the target while minimizing the radiation exposure to normal structures. The IMRT optimization is a complex optimization problem because of the multiple conflicting objectives in it. Due to the complexity of the optimization, the IMRT treatment planning is still a trial and error process. Hierarchical optimization was proposed to automate the treatment planning process, but its potential has not been demonstrated in a clinical setting. Moreover, hierarchical optimization is slower than the traditional optimization. The dissertation studied a sampling algorithm to reduce the hierarchical …

Copper And Zinc Oxide Composite Nanostructures For Solar Energy Harvesting, Fei Wu

McKelvey School of Engineering Theses & Dissertations

Solar energy is a clean and sustainable energy source to counter global environmental issues of rising atmospheric CO2 levels and depletion of natural resources. To extract useful work from solar energy, silicon-based photovoltaic devices are extensively used. The technological maturity and the high quality of silicon (Si) make it a material of choice. However limitations in Si exist, ranging from its indirect band gap to low light absorption coefficient and energy and capital intensive crystal growth schemes. Therefore, alternate materials that are earth-abundant, benign and simpler to process are needed for developing new platforms for solar energy harvesting applications.

In …

Novel Applications Of Electrostatic Precipitators In Coal - Biomass Combustion Systems, He Jing

McKelvey School of Engineering Theses & Dissertations

Pulverized coal combustion is an important source of electricity production worldwide. However, it is also a primary air pollution emission (particulate matters, mercury, etc.) source. Electrostatic precipitators (ESPs) are widely used in coal-fired power plants to control particulate matters. This dissertation contributes in the study of the pollution formation from coal combustion processes and pollution control based on ESPs in the following three aspects: (1) explore novel applications of ESPs in particulate matters and mercury removal; (2) develop and evaluate an compact electrostatic precipitator for sampling purpose, which can support offline fly ash particle analysis; (3) study the submicrometer particle …

Molecularly Targeted Nanoparticles For Modulation Of Inflammatory Mediators In Atherosclerosis, Rohun Udatta Palekar

McKelvey School of Engineering Theses & Dissertations

The enzyme thrombin has been demonstrated through experimental and clinical studies to play a crucial role in mediating both inflammation and thrombosis in atherosclerosis. The cellular effects of thrombin in promoting atherosclerosis involve the activation of signaling pathways that result in the secretion of a host of various chemokines, cytokines, cell adhesion molecules, etc. that promote vascular inflammation. Due in part to thrombin and other pro-atherogenic molecules, this prolonged inflammatory state in atherosclerosis results in the deterioration of the endothelium, increasing the risk of focal thrombosis. Current treatment strategies to address the role of thrombin in atherosclerosis, despite efficacy of …

Drones In Logistics: A Feasible Future Or A Waste Of Effort, Andrew Lotz

Honors Projects

On December 1^st, 2013 news around the world was filled with headlines about E- Commerce website Amazon.com. CEO of Amazon Jeff Bezos announced to the world that Amazon was designing a drone delivery program called Amazon Air that could deliver packages to customers in just 30 minutes. Consumers were all too excited for the program to launch while many business and air traffic savvy people were highly skeptical. Now two years later research to look back at the feasibility of drone flight and whether investment into the technology is worth it for small deliveries straight to customers is …

Tool Material Degradation Due To Friction Stir Welding Of Aluminum Alloys, Corbin T. Collier

Theses and Dissertations

The purpose of this study is to investigate the friction stir welding (FSW) tool material degradation factors due variation in tool material properties and the effect of an aluminum diffusion wear mechanism on three different FSW tool material when exposed to various welding temperatures and times. The degradation factors are essential to FSW tool design due to the effect of the tool pin and shoulders on the heat generation and material flow which directly correlated to the weld quality created during the FSW process. For this investigation the three materials used are H13, TSP1, and MP159. To determine degradation factors …

Confluence Of Density Currents Over An Erodible Bed, Hassan Ismail

Theses and Dissertations

Results from laboratory experiments on conservative density current confluence are reported. Hydraulic characteristics and morphodynamic consequences of the confluence of two continuous release density currents in a horizontal, 45 degree asymmetrical junction are examined and compared to those of terrestrial river junctions. It was observed that density current confluence is markedly different than those in river junctions primarily due to the ease of the dense fluid to convect into the ambient fluid in the junction zone. Upward convection in the junction resulted in low horizontal velocity and shear stresses on the bed of the junction zone, followed by re-plunging to …

Development Of Ultra-Low Loading Of Compressive Pt Lattice Cathode Catalyst On Highly Stable Support For Pemfc Automotive Applications, Tianyuan Xie

Theses and Dissertations

The major barriers in the commercialization of the fuel cell technology for automotive applications are the cost and durability of the Pt catalyst and the support stability at high potentials. The U.S. Department of Energy (DOE) targets direct hydrogen fuel cell systems for transportation to meet 65% peak-efficiency, 5,000 hour durability with a mass production cost of $40/kW by 2020. Currently in 2015, the system can be operated at peak energy efficiency of 60% for 3,900 hours with cost of $55/kW. To meet these targets, precious metal loadings must be greatly reduced without altering the catalyst stability. The primary objective …

Numerical And Experimental Investigations Of Dam And Levee Failure, Ezzat Youssef Elhassan Mohamed Elalfy

Theses and Dissertations

Both numerical and experimental investigations are conducted to study the failure of earthen dams and levees. Boussinesq equations describing one-dimensional unsteady flow including non-hydrostatic pressure distribution are solved numerically along with Exner equation for the sediment mass conservation to include the effects of the streamline curvature on the failure of non-cohesive earthen embankments. In addition, the effects of the steep bottom slope on the flow variables during the failure are studied by solving the Saint- Venant equations modified for steep bed slope along with the Exner equation to simulate non-cohesive earthen embankment failure due to overtopping. The Boussinesq equations are …

Experimental Study Of Longitudinal Sorting Of Particles Differing In Size And Density, Nabila Mahjabeen

Theses and Dissertations

Transport, deposition and erosion of sediment particles differing in size, shape and density may result in particle segregation, which in geosciences applications is generally referred to as sediment sorting. A thorough understanding of sediment sorting processes is important to describe and model a wide variety of natural processes such as the decrease in particle size and/or density in a fluvial system (downstream fining and/or lightening), the formation of economic placers, concentration of heavy minerals, chemical and metal pollutants etc. Sorting of sediment grains associated with sediment transport in the streamwise direction results in the development of longitudinal sorting patterns. Vertical …

Impact Of Formulation And Processing Parameters On Mechanical Properties Of Magadiite/Elastomer Composites, Yating Mao

Theses and Dissertations

This work seeks a better understanding of mechanical reinforcement and energy dissipation in elastomer composites containing the layered silicate magadiite (MGD, Na2Si14O29·nH2O). We characterized the elastomer’s accessibility into MGD interlayer spaces and studied the factors that influence the composite mechanical properties. We also compare the mechanical reinforcement of MGD with montmorillonite (MMT, a layered aluminosilicate clay mineral), which is widely used as filler in other kinds of nanocomposites. The study explores the grafting chemistry, vulcanization, and reinforcement mechanism in MGD/elastomer composites, which may help us to formulate the platelet/elastomer composites with superior mechanical properties and performance in the future. We …

Nd − Pdpa: N Dimensional Probability Density Profile Analysis, Arjang Fahim

Theses and Dissertations

Proteins are often referred as working molecule of a cell, performing many structural, functional and regulatory processes. Revealing the function of proteins still remains a challenging problem. Advancement in genomics sequence projects produces large protein sequence repository, but due to technical difficulty and cost related to structure determination, the number of identified protein structure is far behind. Novel structures identification are particularly important for a number of reasons: they generate models of similar proteins for comparison; identify evolutionary relationships; further contribute to our understanding of protein function and mechanism; and allow for the fold of other family members to be …

Towards The Development Of A Wearable Tremor Suppression Glove, Yue Zhou

Electronic Thesis and Dissertation Repository

Patients diagnosed with Parkinson’s disease (PD) often associate with tremor. Among other symptoms of PD, tremor is the most aggressive symptom and it is difficult to control with traditional treatments. This thesis presents the assessment of Parkinsonian hand tremor in both the time domain and the frequency domain, the performance of a tremor estimator using different tremor models, and the development of a novel mechatronic transmission system for a wearable tremor suppression device. This transmission system functions as a mechatronic splitter that allows a single power source to support multiple independent applications. Unique features of this transmission system include low …

Guided Wave Based Integrated Structural Health Monitoring And Nondestructive Evaluation, Zhenhua Tian

Theses and Dissertations

Damage detection and health monitoring are critical for ensuring the structural safety in various fields, such as aerospace, civil and nuclear engineering. Structural health monitoring (SHM) performs online nondestructive evaluation (NDE) and can predict the structural remaining life through appropriate diagnosis and prognosis technologies. Among various SHM/NDE technologies, guided ultrasonic waves have shown great potential for fast and large area SHM/NDE, due to their sensitivity to small defects and capability to propagate long distances. Recent advances in guided wave based SHM/NDE technologies have demonstrated the feasibility of detecting damage in simple structures such as metallic plates and pipes. However, there …

A Multiphysics Modeling Of Solid Oxide Metal-Air Redox Battery, Md Ahsan Uddin

Theses and Dissertations

Cost-effective and large scale energy storage is essential for the growth of the future’s ‘‘green energy’’ infrastructure. Among the energy storage technologies currently being used, rechargeable batteries represent a class of advanced electrical energy storage (EES) mechanisms that can be valuable for the future renewable integration and smart grid. Rechargeable batteries have innumerous advantages over the conventional pumped hydro and compressed-air energy storage system. Now days, There are various types of rechargeable batteries available to work as an energy storage device in a smart grid but it still needs many breakthroughs to become commercially viable for stationary energy storage. First …

Assessment Of Classifiers For Potential Voice-Enabled Transportation Apps, Md Majbah Uddin

Theses and Dissertations

Transportation apps are playing a positive role for today’s technology-driven users. They provide users with a convenient and flexible tool to access transportation data and services, as well as collect and manage data. In many of these apps, such as Google Maps, their operations rely on the effectiveness of the voice recognition system. For the existing and new apps to be truly effective, the built-in voice recognition system needs to be robust (i.e., being able to recognize words spoken in different pitch and tone). The goal of this study is to assess three post-processing classifiers (i.e., bag-of-sentences, support vector machine, …

Intercode Advanced Fuels And Cladding Comparison Using Bison, Frapcon, And Femaxi Fuel Performance Codes, Aaren Rice

Theses and Dissertations

The high density uranium-based fuels are regaining popularity as the current fleet of LWR’s are showing interest in uprating plants to increase accident tolerance and performance. Fuels such as U3Si2, UN, and UC all contain a higher uranium loading and thermal conductivity than that of UO2 making them attractive in combination with an advanced cladding type such as the ceramic SiC cladding. In addition to adding more mass uranium to the core without surpassing current enrichment limits, these advanced fuels and claddings are designed with increased accident tolerance performance in a LOCA type scenario in mind. One of the possible …

Supported Group Ib-Pd Bimetallic Catalysts Prepared By Electroless Deposition And Galvanic Displacement For Selective Hydrogenation Of Acetylene, Yunya Zhang

Theses and Dissertations

Ethylene is the building block for many chemical intermediates in the petrochemical industry. The current worldwide ethylene production is over 150 million tons per year and demand increases by 3-5% annually. However, ethylene produced from steam cracking of light naptha contains up to 2% acetylene which acts as a poison for the downstream ethylene polymerization catalysts. Selective hydrogenation of acetylene in the ethylene stream using supported Pd catalysts is the industrially preferred method of lowering acetylene to acceptable ppm levels (< 5 ppm). Due to inferior selectivity at high acetylene conversion and the formation of “green oil”, or ethylene/acetylene oligomers, during reaction, small amounts of Group IB metals have been added to improve the performance of current generation catalysts. However, the bimetallic effects of the above additives have not been experimentally confirmed, possibly because the conventional methods of catalyst preparation result in both monometallic and bimetallic particles with varying compositions. This in turn makes it difficult to determine the position of the two metallic components, and bimetallic interactions typically occur only when the two metals form proximal contact instead of separate particles. In this study, a series of Ag- and Au-Pd/SiO2 bimetallic catalysts were prepared by electroless deposition (ED) with incremental and controlled coverages of Ag and Au on Pd. The selectivity of acetylene to ethylene and turnover frequencies of acetylene conversion were enhanced at high coverages of Ag and Au on Pd surfaces due to the transition of acetylene adsorption modes, which was further confirmed by the kinetics of acetylene hydrogenation. The similar performance trends for Ag- and Au-Pd/SiO2 suggest that the bimetallic effect for these catalysts was likely geometric and not electronic in nature. For comparison, a series of reverse Pd-Ag/SiO2 bimetallic catalysts where variable coverages of Pd were deposited onto Ag surfaces was prepared using galvanic displacement (GD) of Ago by Pd2+ to further explore the nature of bimetallic effects for selective acetylene hydrogenation. Unlike for the earlier case for Ag on Pd surfaces using ED, for samples prepared by GD there was considerably diffusion of Pd into the Ag lattice to give greater electronic interactions between these two metals, which limited selectivity of acetylene hydrogenation to form ethylene.

In Situ Ir Spectroscopic Investigation Of Noble Metal Catalysts Related To The Reduction Of Automotive Exhaust Emissions, Zhiyong Wang

Theses and Dissertations

The reduction of automotive exhaust emissions has been one of the hottest topics in catalysis community since 1970s. Thanks to the development of three-way catalysts, main auto-exhaust pollutants, such as carbon monoxide, nitrogen oxides and unburned hydrocarbons, can be removed simultaneously. Nowadays, diesel engines and lean-engines become more and more popular due to their high fuel-efficiency and low CO2 emissions. Unfortunately, conventional three-way catalysts are not effective at reducing the NOx emissions from these engines due to the excess oxygen in the exhaust stream. Platinum catalysts were found to be highly active for selective NO reduction with hydrocarbons in excess …

Effects Of Cell Adhesion Peptides, Ph, And Matrix Shape On Maintenance Of Breast Cancer Stem Cells In An Engineered Hydrogel Matrix, Leily Daneshian

Theses and Dissertations

Metastasis, resistance to chemo- and radiotherapy, and eventual relapse has been attributed to a tumor subpopulation known as cancer stem cells (CSCs). CSCs are regulated in their tumor microenvironment by various factors. Synthetic hydrogels can be used to investigate the effects of individual environmental factors on CSCs by providing inert 3D matrices. In this thesis, poly ethylene glycol diacrylate (PEGDA) hydrogel with 5kpa modulus has been used as a culture system to study the effect of; I) integrin and heparin binding peptides, 2) pH, and 3) the shape of the microenvironment on breast CSCs maintenance and tumorsphere formation in PEGDA. …

Preparation And Characterization Of Pt-Ru Bimetallic Catalysts Using Electroless Deposition Methods And Mechanistic Study Of Re And Cs Promoters For Ag-Based, High Selectivity Ethylene Oxide Catalysts, Weijian Diao

Theses and Dissertations

Pt-Ru bimetallic catalysts are widely used for direct methanol fuel cells, biomass upgrading and hydrocarbon refining and offer unique properties compared to Pt or Ru monometallic catalysts due to ensemble effects, electronic effects, and/or bifunctional effects. To achieve better performance, strong metal-metal interactions and true bimetallic surface are needed. Electroless deposition (ED) methods are used in our laboratory to synthesize such bimetallic catalysts. In this study, two series of Ru@Pt/C (Pt deposited on Ru surfaces) and Pt@Ru/C (Ru deposited on Pt surfaces) catalysts have been synthesized. Characterization data from temperature programmed reduction (TPR), selective chemisorption, X-ray photoelectron spectroscopy (XPS), and …

Industrial Robot Acceptance: Effects Of Workforce Demographics And Establishing A Culture Of Acceptance Within Manufacturing Industry, Melissa M. Henderson

Theses and Dissertations

Industrial applications have not been extensively researched regarding human-robot interaction. This project investigated industrial robot acceptance in the context of one manufacturing site. Acceptance was examined in relation to the workforce and conditions of acceptance were identified using mixed methodology. Quantitative (surveys) and qualitative (interviews) data was used to measure and analyze the existing state of technology acceptance and site culture. Based on this exploratory study, it was found the manufacturing facility has a weak culture but would be generally accepting of industrial robots if the technology were easy to use and useful. The identified boundary conditions to acceptance included …