Digital Commons Network^™

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 …

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 …

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 …

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 …

Momentum Of Particles From Time-Of-Flight Measurements, Joseph Best

Senior Theses

In order to find the momentum of particles from time of flight measurements, I used a program called Geant4 to simulate experiments. I made a simple two detector setup, and I recreated a real world experiment. I spent a lot of time learning to code in C++ so I could use Geant4 correctly. I simulated these experiments shooting electrons, muons, and pions through the geometry and measured the time at two points in their flight. Subtracting the second time from the first gave me the time of flight distribution for each particle. I used ROOT to draw histograms of the …

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 …

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 …

Clinical Application Of Electrocardiographic Imaging In Patients With Ischemic Cardiomyopathy, Early Repolarization Syndrome And Brugada Syndrome, Junjie Zhang

McKelvey School of Engineering Theses & Dissertations

Electrocardiographic Imaging (ECGI) is a noninvasive modality for human application in both research and clinical settings. It is an important tool for investigation of abnormal electrophysiological (EP) substrates and arrhythmias in patients. Multi-channel body surface potential recordings and the patient-specific heart-torso geometry from ECG gated computed tomography are processed by ECGI algorithms to reconstruct epicardial potentials, electrograms and patterns of activation and repolarization. ECGI is able to continuously generate high-resolution, panoramic EP maps of the entire heart on a beat-by-beat basis, which cannot be achieved with invasive catheter mapping.

ECGI was applied in ischemic cardiomyopathy patients to characterize the abnormal …

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. …

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 …

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 …

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 …

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 …

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, …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

Surface Modification Of Nanodiamond And Its Incorporation In Nanodiamond/Peek Nanocomposites, Zahidul Wahab

Theses and Dissertations

The continued miniaturization of electronic device components requires new lightweight polymers with high thermal stability, high thermal conductivity, low electrical conductivity, and low dielectric constant. Composites of nanodiamond (ND) and poly(ether ether ketone) (PEEK) are candidates for these applications due their unique combination of properties. The objectives of this research are to explore new routes for surface functionalization of nanodiamond (ND), develop methods for maximizing dispersion of ND as a nano-scale filler in PEEK, and characterize the effect of dispersed ND on the mechanical, thermal and dielectric properties of ND/PEEK composites. Initial attempts to disperse different kinds of commercially available, …

Bio-Inspired Design Of Mechanical Band Pass Sensor With The Ability To Scavenge Energy, Md Riaz Uddin Ahmed

Theses and Dissertations

Primary objective of this work is to introduce the multi-scale computational model for the bio-inspired acousto-ultrasonic band pass sensor that are capable of mechanically sense and/or filter wide range user defined frequencies. Selecting a particular and/or a distinct band of frequencies is essential for many applications in science engineering and technologies. For example design of sensors in chemical, biomedical and biological applications; device application for acoustic modulation by breaking the acoustic reciprocity and the sensors used in precision manufacturing applications requires sensing and/or filtering of wide range of acousto-ultrasonic frequencies. Presently, electronic devices are widely employed in commercial applications for …

Dielectric Characteristics Of Microstructural Changes And Property Evolution In Engineered Materials, Jallisa Janet Clifford

Theses and Dissertations

Heterogeneous materials are increasingly used in a wide range of applications such as aerospace, civil infrastructure, fuel cells and many others. The ability to take properties from two or more materials to create a material with properties engineered to specific needs is always very attractive. Hence engineered materials are evolving into more complex formulations or heterogeneities in multiple disciplines. Design of microstructure at multiple scales controls the global functional properties of these materials and their structures. However, local microstructural changes do not directly cause a proportional change to the global properties (such as strength and stiffness). Instead, local changes follow …

Slope Stability Enhancement Of An Upstream Tailings Dam: Laboratory Testing And Numerical Modelling, Yazeed A. Alsharedah

Electronic Thesis and Dissertation Repository

Mine tailings are the byproduct of mining activities, which need to be disposed of once the ore is extracted. They can be disposed of in either dry or wet forms. The latter is most common with the tailings being disposed of in the form of slurry inside retention structures. The retention structure may be a natural, manmade, or built dam, which is the case in most of nowadays mining locations. In this thesis, improving the stability of an upstream tailings dam using soil additives is investigated. The experimental phase of this study involved laboratory tests conducted to characterize mine tailings …

Security Protocol Suite For Preventing Cloud-Based Denial-Of-Service Attacks, Marwan M. Darwish

Electronic Thesis and Dissertation Repository

Cloud systems, also known as cloud services, are among the primary solutions of the information technology domain. Cloud services are accessed through an identity authentication process. These authentication processes have become increasingly vulnerable to adversaries who may perform denial-of-service (DoS) attacks to make cloud services inaccessible. Several strong authentication protocols have been employed to protect conventional network systems. Nevertheless, they can cause a DoS threat when implemented in the cloud-computing system. This is because the comprehensive verification process may exhaust the cloud resources and shut down cloud’s services. This thesis proposes a novel cloud-based secure authentication (CSA) protocol suite that …

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 …

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 …