Engineering Commons^™

Genetic Algorithms In Stochastic Optimization And Applications In Power Electronics, Mengmei Liu

Theses and Dissertations--Electrical and Computer Engineering

Genetic Algorithms (GAs) are widely used in multiple fields, ranging from mathematics, physics, to engineering fields, computational science, bioinformatics, manufacturing, economics, etc. The stochastic optimization problems are important in power electronics and control systems, and most designs require choosing optimum parameters to ensure maximum control effect or minimum noise impact; however, they are difficult to solve using the exhaustive searching method, especially when the search domain conveys a large area or is infinite. Instead, GAs can be applied to solve those problems. And efficient computing budget allocation technique for allocating the samples in GAs is necessary because the real-life problems …

Mathematical Model For Current Transformer Based On Jiles-Atherton Theory And Saturation Detection Method, Xiang Li

Theses and Dissertations--Electrical and Computer Engineering

Current transformer saturation will cause the secondary current distortion. When saturation occurs, the secondary current will not be linearly proportional to the primary current, which may lead to maloperation of protection devices. This thesis researches and tests two detecting methods: Fast Fourier Transform (FFT) and Wavelet Transform based methods. Comparing these two methods, FFT has a better performance in steady state saturation, and Wavelet Transform can determine singularity to provide the moment of distortion.

The Jiles-Atherton (J-A) theory of ferromagnetic hysteresis is one approach used in electromagnetics transient modeling. With decades of development, the J-A model has evolved into different …

Small Satellite Noncommutative Rotation Sequence Attitude Control Using Piezoelectric Actuators, Joshua L. Evans

Theses and Dissertations--Electrical and Computer Engineering

Attitude control remains one of the top engineering challenges faced by small satellite mission planning and design. Conventional methods for attitude control include propulsion, reaction wheels, magnetic torque coils, and passive stabilization mechanisms, such as permanent magnets that align with planetary magnetic fields. Drawbacks of these conventional attitude control methods for small satellites include size, power consumption, dependence on external magnetic fields, and lack of full control authority. This research investigates an alternative, novel approach to attitude-control method for small satellites, utilizing the noncommutative property of rigid body rotation sequences. Piezoelectric bimorph actuators are used to induce sinusoidal small-amplitude satellite …

Bioactive Poly(Beta-Amino Ester) Biomaterials For Treatment Of Infection And Oxidative Stress, Andrew L. Lakes

Theses and Dissertations--Chemical and Materials Engineering

Polymers have deep roots as drug delivery tools, and are widely used in clinical to private settings. Currently, however, numerous traditional therapies exist which may be improved through use of polymeric biomaterials. Through our work with infectious and oxidative stress disease prevention and treatment, we aimed to develop application driven, enhanced therapies utilizing new classes of polymers synthesized in-house. Applying biodegradable poly(β-amino ester) (PBAE) polymers, covalent-addition of bioactive substrates to these PBAEs avoided certain pitfalls of free-loaded and non-degradable drug delivery systems. Further, through variation of polymer ingredients and conditions, we were able to tune degradation rates, release profiles, cellular …

Synthesis And Characterization Of Antioxidant Conjugated Poly(Βeta-Amino Ester) Micro/Nanogels For The Suppression Of Oxidative Stress, Prachi Gupta

Theses and Dissertations--Chemical and Materials Engineering

Oxidative stress is a pathophysiological condition defined by an increased production of reactive oxygen species (ROS), which can result in the growth arrest of cells followed by cell disintegration or necrosis. A number of small molecule antioxidants (e.g. curcumin, quercetin and resveratrol) are capable of directly scavenging ROS, thereby short-circuiting the self-propagating oxidative stress state. However, poor solubility and rapid 1^st pass metabolism results in overall low bioavailability and acts as a barrier for its use as a drug to suppress oxidative stress efficiently.

To overcome this limitation, these small molecule antioxidants were covalently conjugated into poly(β-amino ester) (PβAE) …

Improving The Capacity, Durability And Stability Of Lithium-Ion Batteries By Interphase Engineering, Qinglin Zhang

Theses and Dissertations--Chemical and Materials Engineering

This dissertation is focus on the study of solid-electrolyte interphases (SEIs) on advanced lithium ion battery (LIB) anodes. The purposes of this dissertation are to a) develop a methodology to study the properties of SEIs; and b) provide guidelines for designing engineered SEIs. The general knowledge gained through this research will be beneficial for the entire battery research community.

Peptide-Functionalized Magnetic Nanoparticles For Cancer Therapy Applications, Anastasia K. Hauser

Theses and Dissertations--Chemical and Materials Engineering

Lung cancer is one of the leading causes of cancer deaths in the United States. Radiation and chemotherapy are conventional treatments, but they result in serious side effects and the probability of tumor recurrence remains high. Therefore, there is an increasing need to enhance the efficacy of conventional treatments. Magnetic nanoparticles have been previously studied for a variety of applications such as magnetic resonance imaging contrast agents, anemia treatment, magnetic cell sorting and magnetically mediated hyperthermia (MMH). In this work, dextran coated iron oxide nanoparticles were developed and functionalized with peptides to target the nanoparticles to either the extracellular matrix …

Design Of Highly Stable Low-Density Self-Assembled Monolayers Using Thiol-Yne Click Reaction For The Study Of Protein-Surface Interactions, Leila Safazadeh Haghighi

Theses and Dissertations--Chemical and Materials Engineering

Protein adsorption on solid surfaces is a common yet complicated phenomenon that is not fully understood. Self-assembled monolayers have been utilized in many studies, as well-defined model systems for studying protein-surface interactions in the atomic level. Various strategies, including the use of single component SAMs[1, 2], combinations of long and short alkanethiolates with methyl- and hydroxyl- terminal groups[3, 4], and using mixtures of alkanethiolates with similar chain length and varying terminal functional group [5] have been used to effectively control the surface wettability and determine the effect of surface composition and wettability on protein adsorption. In this dissertation we report …

Three-Dimensional Microstructural Effects On Multi-Site Fatigue Crack Nucleation Behaviors Of High Strength Aluminum Alloys, Yan Jin

Theses and Dissertations--Chemical and Materials Engineering

An experimental method was further developed to quantify the anisotropy of multi-site fatigue crack initiation behaviors in high strength Al alloys by four-point bend fatigue testing under stress control. In this method, fatigue crack initiation sites (fatigue weak-links, FWLs) were measured on the sample surface at different cyclic stress levels. The FWL density in an alloy could be best described using a three-parameter Weibull function of stress, though other types of sigmoidal functions might also be used to quantify the relationship between FWL density and stress. The strength distribution of the FWLs was derived from the Weibull function determined by …

Understanding Electrical Conduction In Lithium Ion Batteries Through Multi-Scale Modeling, Jie Pan

Theses and Dissertations--Chemical and Materials Engineering

Silicon (Si) has been considered as a promising negative electrode material for lithium ion batteries (LIBs) because of its high theoretical capacity, low discharge voltage, and low cost. However, the utilization of Si electrode has been hampered by problems such as slow ionic transport, large stress/strain generation, and unstable solid electrolyte interphase (SEI). These problems severely influence the performance and cycle life of Si electrodes. In general, ionic conduction determines the rate performance of the electrode, while electron leakage through the SEI causes electrolyte decomposition and, thus, causes capacity loss. The goal of this thesis research is to design Si …

Synthesis Of Titania Thin Films With Controlled Mesopore Orientation: Nanostructure For Energy Conversion And Storage, Suraj R. Nagpure

Theses and Dissertations--Chemical and Materials Engineering

This dissertation addresses the synthesis mechanism of mesoporous titania thin films with 2D Hexagonal Close Packed (HCP) cylindrical nanopores by an evaporation-induced self-assembly (EISA) method with Pluronic surfactants P123 and F127 as structure directing agents, and their applications in photovoltaics and lithium ion batteries. To provide orthogonal alignment of the pores, surface modification of substrates with crosslinked surfactant has been used to provide a chemically neutral surface. GISAXS studies show not only that aging at 4°C facilitates ordered mesostructure development, but also that aging at this temperature helps to provide orthogonal orientation of the cylindrical micelles which assemble into an …

Three-Dimensional Microstructure-Based Models For Fatigue Crack Nucleation And Fatigue Crack Branching In High Strength Al Alloys, Lin Yang

Theses and Dissertations--Chemical and Materials Engineering

This study is concerned with using numerical three-dimensional microstructure-based models to quantify the multi-site fatigue crack initiation behaviors by simulating the effects of pores in a cast aluminum alloy, and to analyze the mechanism of fatigue crack branching in thick aluminum alloy plates. It has been recently recognized the three-dimensional effects of pores on fatigue crack initiation, which provide opportunity to quantitatively identify the fatigue weak-link density and strength distribution in aluminum alloy. The stress and strain fields around a micro-pore in an A713 aluminum alloy (an elasto-plastic media) under cyclic loading were quantified as a function of pore position …

Lnvestigation Of The Critical Role Of Polymeric Binders For Silicon Negative Electrodes In Lithium-Lon Batteries, Jiagang Xu

Theses and Dissertations--Chemical and Materials Engineering

Silicon is capable of delivering a high theoretical specific capacity of 3579 mAh g^-1, which is about 10 times higher than that of the state-of-the-art graphite-based negative electrodes for lithium-ion batteries (LIBs). However, the poor cycle life of silicon electrodes, caused by the large volumetric strain during cycling, limits the commercialization of silicon electrodes. As one of the essential components, the polymeric binder is critical to the performance and durability of lithium-ion batteries as it keeps the integrity of electrodes, maintains conductive path and must be stable in the electrolyte. The guideline for binder selection of silicon electrodes …

First-Principles Studies Of Structure-Property Relationships: Enabling Design Of Functional Materials, Qunfei Zhou

Theses and Dissertations--Chemical and Materials Engineering

First-principles calculations based on quantum mechanics have been proved to be powerful for accurately regenerating experimental results, uncovering underlying myths of experimental phenomena, and accelerating the design of innovative materials. This work has been motivated by the demand to design next-generation thermionic emitting cathodes and techniques to allow for synthesis of photo-responsive polymers on complex surfaces with controlled thickness and patterns. For Os-coated tungsten thermionic dispenser cathodes, we used first-principles methods to explore the bulk and surface properties of W-Os alloys in order to explain the previously observed experimental phenomena that thermionic emission varies significantly with W-Os alloy composition. Meanwhile, …

Development And Preliminary Evaluation Of A Spray Deposition Sensing System For Improving Pesticide Application, Melissa A. Kesterson, Joe D. Luck, Michael P. Sama

Biosystems and Agricultural Engineering Faculty Publications

An electronic, resistance-based sensor array and data acquisition system was developed to measure spray deposition from hydraulic nozzles. The sensor surface consisted of several parallel tin plated copper traces of varying widths with varying gap widths. The system contained an embedded microprocessor to monitor output voltage corresponding to spray deposition every second. In addition, a wireless module was used to transmit the voltage values to a remote laptop. Tests were conducted in two stages to evaluate the performance of the sensor array in an attempt to quantify the spray deposition. Initial tests utilized manual droplet placement on the sensor surface …

High Capacity Silicon Electrodes With Nafion As Binders For Lithium-Ion Batteries, Jiagang Xu, Qinglin Zhang, Yang-Tse Cheng

Chemical and Materials Engineering Faculty Publications

Silicon is capable of delivering a high theoretical specific capacity of 3579 mAh g⁻¹ which is about 10 times higher than that of the state-of-the-art graphite based negative electrodes for lithium-ion batteries. However, the poor cycle life of silicon electrodes, caused by the large volumetric strain during cycling, limits the commercialization of silicon electrodes. As one of the essential components, the polymeric binder is critical to the performance and durability of lithium-ion batteries as it keeps the integrity of electrodes, maintains conductive path and must be stable in the electrolyte. In this work, we demonstrate that electrodes consisting of …

An Organic Mixed Ion-Electron Conductor For Power Electronics, Abdellah Malti, Jesper Edberg, Hjalmar Granberg, Zia Ullah Khan, Jens W. Andreasen, Xianjie Liu, Dan Zhao, Hao Zhang, Yulong Yao, Joseph W. Brill, Isak Engquist, Mats Fahlman, Lars Wågberg, Xavier Crispin, Magnus Berggren

Physics and Astronomy Faculty Publications

A mixed ionic–electronic conductor based on nanofibrillated cellulose composited with poly(3,4-ethylene-dioxythio­phene):­poly(styrene-sulfonate) along with high boiling point solvents is demonstrated in bulky electrochemical devices. The high electronic and ionic conductivities of the resulting nanopaper are exploited in devices which exhibit record values for the charge storage capacitance (1F) in supercapacitors and transconductance (1S) in electrochemical transistors.

Properties Of Pan Fibers Solution Spun Into A Chilled Coagulation Bath At High Solvent Compositions, E. Ashley Morris, Matthew C. Weisenberger, Gregory Wilson Rice

Center for Applied Energy Research Faculty and Staff Publications

In this work, multifilament, continuous polyacrylonitrile (PAN) fiber tow was solution spun mimicking industrial processing at the small pilot scale (0.5 k tow), while carefully altering the composition of the coagulation bath, in order to determine the effect on the resulting fiber shape, density, orientation, and tensile properties at varying points in the spinning process. Novel here are the abnormally high coagulation bath solvent compositions investigated, which surpass those often reported in the literature. In addition, the coagulation bath was maintained at a slightly chilled temperature, contrary to reported methods to produce round fibers. Further, by altering the composition of …

Creating A Highway Information System For Safety Roadway Features, Brian K. Howell, Kenneth R. Agent, Eric Green

Kentucky Transportation Center Research Report

Roadway departures are the leading cause of roadside fatalities. The Kentucky Transportation Cabinet (KYTC) has undertaken a number of roadside safety measures to reduce roadway departures. Specifically, KYTC has installed several low-cost, systemic roadway safety treatments to Kentucky’s roadways in recent years. These treatments include cable barriers, high friction surface treatments, rumble stripes, and Safety Edges. KYTC has installed approximately 44 cable barrier systems over 265 miles of roadway,112 HFST applications over 20 miles of roadway, 750 rumble stripe installations over 2,500 miles of roadway, and 147 Safety Edge treatments on 580 miles of roadway. The project team developed a …

Fiscal Year 2015 Fhwa-536 Report For The Kentucky Transportation Cabinet, Steven Douglas Kreis, Candice Y. Wallace, Bryan Gibson, Sarah M. Mccormack

Kentucky Transportation Center Research Report

The Federal Highway Administration (FHWA) requires state transportation agencies to submit a biennial report on local highway finances. The purpose of these reports is to provide FHWA with the data it needs to capture the financing of highway activities at the local level. Based on this information, it can identify trends in revenue, expenditures, investments, and program development, and in turn make decisions about future investments. The report, FHWA-536, asks agencies to report on four areas of local highway finance: 1) disposition of highway-user revenues; 2) revenues used for roads and streets identified by source and funding type; 3) road …

Evaluation Of Thermal Imaging Technology For Commercial Vehicle Screening, Jennifer R. Walton, Mark S. Spellman, Joseph D. Crabtree

Kentucky Transportation Center Research Report

Brake and tire violations are common problems identified through commercial vehicle inspections. Identifying and correcting these types of problems before a crash occurs can produce significant safety benefits. Thermal imaging technology can be used by commercial vehicle enforcement to screen vehicles as they approach a weigh station to determine if they may have flat tires and inoperable brakes. The vehicles do not have to be stopped at a weigh station to be screened. Kentucky currently has three stations outfitted with thermal imaging technology. The objectives of this study were to evaluate the benefits of using the thermal imaging cameras to …

Methodology Update For Estimating Volume To Service Flow Ratio, Mei Chen, Xu Zhang

Kentucky Transportation Center Research Report

Volume/service flow ratio (VSF) is calculated by the Highway Performance Monitoring System (HPMS) software as an indicator of peak hour congestion. It is an essential input to the Kentucky Transportation Cabinet’s (KYTC) key planning applications, such as highway adequacy rating. After the Federal Highway Administration (FHWA) reassessed the HPMS, the standalone HPMS software was no longer supported. This conclusion was based on the 2000 Highway Capacity Manual (HCM2000). As a result, the peak capacity and VSF estimates based on the submittal file are no longer available to KYTC. The calculation of VSF ratios requires AADT, K factor, directional factor, and …

Update Of Data For Estimating Esals, Jerry G. Pigman, R. Clark Graves, Brad W. Rister, David H. Cain, Neil Tollner

Kentucky Transportation Center Research Report

This project involved updating processing traffic characteristics data using a series of quality control and analytical programs to produce an estimate of the following parameters of interest; 1) average daily traffic, 2) percent trucks, 3) percent trucks classified as heavy/coal, 4) axles per truck, 5) axles per heavy/coal truck, 6) ESALs per truck axle, 7) ESALs per heavy/coal truck axle, and 8) total ESALs. ESAL estimation parameters used WIM data collected during 2007, 2011, and 2012–2013 (representing 41 stations); and classification data collected in 2010, 2011 and 2012 (representing 1,669 stations).

Computer programs used to process classification data, process weight …

Petrology And Geochemistry Of The Harlan, Kellioka, And Darby Coals From The Louellen 7.5-Minute Quadrangle, Harlan County, Kentucky, Michelle N. Johnston, James C. Hower, Shifeng Dai, Peipei Wang, Panpan Xie, Jingjing Liu

Center for Applied Energy Research Faculty and Staff Publications

The Harlan, Kellioka, and Darby coals in Harlan County, Kentucky, have been among the highest quality coals mined in the Central Appalachians. The Middle Pennsylvanian coals are correlative with the Upper Elkhorn No. 1 to Upper Elkhorn No. 3½ coals to the northwest of the Pine Mountain thrust fault. Much of the mining traditionally was controlled by captive, steel-company-owned mines and the coal was part of the high volatile A bituminous portion of the coking coal blend. Overall, the coals are generally low-ash and low-sulfur, contributing to their desirability as metallurgical coals. We did observe variation both in geochemistry, such …

2d Cine Dense With Low Encoding Frequencies Accurately Quantifies Cardiac Mechanics With Improved Image Characteristics, Gregory J. Wehner, Jonathan D. Grabau, Jonathan D. Suever, Christopher M. Haggerty, Linyuan Jing, David Powell, Sean M. Hamlet, Moriel H. Vandsburger, Xiaodong Zhong, Brandon K. Fornwalt

Biomedical Engineering Faculty Publications

BACKGROUND: Displacement Encoding with Stimulated Echoes (DENSE) encodes displacement into the phase of the magnetic resonance signal. The encoding frequency (k_e) maps the measured phase to tissue displacement while the strength of the encoding gradients affects image quality. 2D cine DENSE studies have used a k_e of 0.10 cycles/mm, which is high enough to remove an artifact-generating echo from k-space, provide high sensitivity to tissue displacements, and dephase the blood pool. However, through-plane dephasing can remove the unwanted echo and dephase the blood pool without relying on high k_e. Additionally, the high sensitivity comes …

Chemical Processing Cell With Nanostructured Membranes, Dibakar Bhattacharyya, Scott R. Lewis, Saurav Datta

Chemical and Materials Engineering Faculty Patents

A chemical processing cell includes an upstream membrane and a downstream membrane. The upstream membrane generates a first reaction product. The downstream membrane converts the first reaction product to a second reaction product.

Nitrogen Fertilizer Composition And Method To Improve Detection And Lessen The Explosive Potential Of Nitrogen-Based Fertilizers, Darrell Neal Taulbee

Center for Applied Energy Research Faculty Patents

A nitrogen fertilizer composition includes urea and a nitrate-based fertilizer such as ammonium nitrate, calcium ammonium nitrate and mixtures of ammonium nitrate and calcium ammonium in which the urea and total nitrogen are at concentrations of 20 percent by weight or greater and the concentration of ammonium nitrate is at 30 percent or greater by weight. One or both of the urea and nitrate-based fertilizer are coated with an agriculturally compatible material. The fertilizer composition provides significant nitrate nitrogen for legitimate agricultural use yet is not amenable to the production of an explosive by crushing or by aqueous extraction. A …

Electrode Kinetics Of Vanadium Flow Batteries: Contrasting Responses Of VIi-VIii And VIv-VV To Electrochemical Pretreatment Of Carbon, A. Bourke, M. A. Miller, R. P. Lynch, Xin Gao, James Landon, J. S. Wainright, R. F. Savinell, D. N. Buckley

Center for Applied Energy Research Faculty and Staff Publications

Electrochemical impedance spectroscopy and cyclic voltammetry were used to investigate the electrode kinetics of V^II-V^III and V^IV-V^V in H₂SO₄ on glassy carbon, carbon paper, carbon xerogel, and carbon fibers. It was shown that, for all carbon materials investigated, the kinetics of V^II-V^III is enhanced by anodic, and inhibited by cathodic, treatment of the electrode; in contrast, the kinetics of V^IV-V^V is inhibited by anodic, and enhanced by cathodic, treatment. The potential region for each of these effects varied only slightly with carbon material. Rate constants …

Nanowire Cds-Cdte Solar Cells With Molybdenum Oxide As Contact, Hongmei Dang, Vijay P. Singh

Electrical and Computer Engineering Faculty Publications

Using a 10 nm thick molybdenum oxide (MoO_3-x) layer as a transparent and low barrier contact to p-CdTe, we demonstrate nanowire CdS-CdTe solar cells with a power conversion efficiency of 11% under front side illumination. Annealing the as-deposited MoO₃ film in N₂ resulted in a reduction of the cell's series resistance, from 9.97 Ω/cm² to 7.69 Ω/cm², and increase in efficiency from 9.9% to 11%. Under illumination from the back, the MoO_3-x/Au side, the nanowire solar cells yielded J_sc of 21 mA/cm² and efficiency of 8.67%. Our results demonstrate …

Commercial Truck Parking And Other Safety Issues, Jerry G. Pigman, Graham Winchester, Nathaniel Swallom

Kentucky Transportation Center Research Report

Commercial truck parking is a safety issue, since trucks are involved in approximately 10% of all fatal accidents on interstates and parkways in Kentucky. Drivers experience schedule demands and long hours on the road, yet they cannot easily determine available parking locations. The objective of this study was to identify information related to parking demand, locations with documented or potential safety issues, and potential countermeasures. The literature review indicated substantial research has been done on commercial vehicle parking, and works have outlined the necessary facilities to accommodate trucks before drivers exceed their allowable hours of driving. Attention to commercial truck …