Engineering Commons^™

Silica Nanoporous Confinement Effects On Ionic Liquid Properties For Better Design Of Small Molecule Separation, Electrochemical Devices And Drug Delivery, Yuxin He

Theses and Dissertations--Chemical and Materials Engineering

Silica nanoconfinement provides a high level of control of ionic liquids (ILs) in localizing catalysts, creating distinct environment for tuning reactivity and controlling the partition of solvents, reactants and products. Silica thin films with two different pore sizes (2.5 nm and 8 nm) were synthesized to study the effect of nanopore confinement on ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF₆]), and 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]). Silica thin films with accessible 8 nm pore diameters were synthesized using evaporation-induced self-assembly (EISA) with Pluronic P123 as templating surfactant on a chemically neutral modified substrate. The silica films with similar orthogonal aligned mesostructured but …

Nanostructured Metal Thin Films As Components Of Composite Membranes For Separations And Catalysis, Michael J. Detisch

Theses and Dissertations--Chemical and Materials Engineering

Novel metallic thin film composite membranes are synthesized and evaluated in this work for improved separations and catalysis capabilities. Advances in technology that allow for improved membrane performance in solvent separations are desirable for low molecular weight organic separation applications such as those in pharmaceutical industries. Additionally, the introduction of catalytic materials into membrane systems allow for optimization of complex processes in a single step. By adding a nanostructured metallic thin film to its surface, a polymer membrane may be modified to exhibit these improved properties. Using magnetron sputtering, thin metal films may be deposited on commercially available membranes to …

A Framework For Heterologous Biosynthesis Of Natural Products In Mammalian Cells Via Polymer-Mediated Transfections, Logan Warriner

Theses and Dissertations--Chemical and Materials Engineering

With the promise to treat a multi-faceted list of serious inherited and acquired diseases, such as cancer, neurodegenerative and infectious diseases, and inherited genetic indications, gene therapy has continued to push the boundaries of traditional medicine since its earliest implementation. While much progress has been made, clinical success has largely remained elusive. Immunogenicity, difficulty producing commercially relevant quantities, and having a limited genetic payload still limits the ability of viruses to act as directed delivery agents for genetic material. As such, researchers have turned to cationic synthetic materials as a means of delivering nucleic acids, which can circumvent the immune …

Microfiltration Membrane Pore Functionalization Approaches For Chloro-Organic Remediation To Heavy Metal Sorption, Mohammad Saiful Islam

Theses and Dissertations--Chemical and Materials Engineering

Microfiltration polyvinylidene fluoride (PVDF) membranes have distinct advantage for open structure in terms of high internal surface area and ease of access in the pore domain. Functionalization of PVDF membranes with different functional groups (-COOH, -OH, -SH) enables responsive (pH, temperature) properties to membrane, tuning of effective pore size, controlling permeate flux. PVDF microfiltration membrane functionalization with suitable responsive polymer such as poly acrylic acid (PAA) to incorporate carboxyl (-COOH) group enables further modification of functionalized PAA-PVDF membranes for different application ranging from catalysis, bio reactor to heavy metal sorption platform. As a catalytic reactor bed, this PAA-PVDF membranes are …

The Development Of Temperature And Ph Responsive Hydrogels And Membranes For Selective Sorption Of Perfluoroorganics And Nanoparticle Integrated Catalytic Degradation Of Pcb, Anthony Saad

Theses and Dissertations--Chemical and Materials Engineering

The functionalization and use of responsive and catalytic polymeric membranes and materials were explored for contaminant capture and degradation. While membranes have a wide variety of uses across multiple industries, the inclusion of materials that are temperature and pH responsive in the membrane pore domain yields a wide range of applications and possibilities for water treatment. Temperature and pH responsive polymers, as well as controlled nanostructured materials, were synthesized in membrane pores for advanced adsorption-desorption and catalytic treatment of emerging organic contaminants in water. In this study, supported by the NIEHS, poly-N-isopropylacrylamide (PNIPAm) was used as a model thermo-responsive polymer, …

Understanding And Mitigating The Electrochemical-Mechanical Degradation Of High Capacity Battery Electrodes, Dingying Dang

Theses and Dissertations--Chemical and Materials Engineering

Lithium-ion batteries (LIBs) with high energy density and cycling stability play a critical role in developing electric vehicle (EV) and grid energy storage techniques. The electrochemical performance of LIBs can be improved by using high capacity positive (e.g., LiNi_1/3Mn_1/3Co_1/3O₂, i.e., NMC111) and negative (e.g., silicon) electrodes; both, however, experience severe electrochemical-mechanical degradation caused by the lithiation/delithiation induced volume changes. Understanding mechanical degradation mechanisms and their relationships with the capacity fading of electrodes is important for improving the cycling stability of electrodes as well as optimizing the design of electrodes with high capacity …

A Thermodynamic And Feasibility Study Of Green Solvents For The Fabrication Of Water Treatment Membranes, Xiaobo Dong

Theses and Dissertations--Chemical and Materials Engineering

Nonsolvent induced phase separation (NIPS) has been widely used to fabricate polymeric membranes. In NIPS, a polymer is dissolved in a solvent to form a dope solution, which is then cast on a substrate and immersed in a nonsolvent bath, where phase inversion occurs. Petroleum-derived organic solvents, such as N-Methyl-2-Pyrrolidone (NMP) and Dimethylacetamide (DMAc), have been traditionally used to fabricate polymeric membranes via NIPS. However, these solvents may have negative impacts on environmental and human health; therefore, using greener and less toxic solvents, preferably derived from biomass, is of great interest to make membrane fabrication sustainable. In this dissertation, two …

Heart Tissue Reconstruction By Light-Controlled Cell Adhesion, Patterning And Alignment On Decellularized Scaffolds, Cong Li

Theses and Dissertations--Chemical and Materials Engineering

There is an urgent demand for engineered tissues and organs because of extremely limited donor tissues available for transplant. The challenge of tissue rejection has motivated many researchers to try to remove all of the cells from a heart and then add back in patient matched cells. These recellularized hearts are a promising avenue towards a functional bioartifical heart that is less likely to be rejected. Decellularized extracellular matrix (ECM) scaffolds generated from animal hearts do not have the cellular components that elicit immune rejection in patient, and they also preserve the native heart tissue structure. While decellularization techniques are …

Effects Of Hole Transporting Layers And Surface Ligands On Interface Energetics And Photovoltaic Performance Of Methylammonium Lead Iodide Perovskites, So Min Park

Theses and Dissertations--Chemical and Materials Engineering

Organic metal halide perovskites are promising materials for various optoelectronic device applications such as light emitting diodes (LED) and photovoltaic (PV) cells. Perovskite solar cells (PSCs) have shown dramatic increases in power conversion efficiency over the previous ten years, far exceeding the rate of improvement of all other PV technologies. PSCs have attracted significant attention due to their strong absorbance throughout the visible region, high charge carrier mobilities, color tunability, and ability to make ultralight weight devices. However, organic metal halide perovskites still face several challenges. For example, their environmental stability issue must be overcome to enable widespread commercialization. Meeting …

Polymeric Nanocomposite Membranes With Phosphorene Based Pore Fillers For Fouling Control, Joyner Eke

Theses and Dissertations--Chemical and Materials Engineering

Phosphorene is a two-dimensional material exfoliated from bulk phosphorus. Specifically, relevant to the field of membrane science, the band gap of phosphorene provides it with potential photocatalytic properties, which could be explored in making reactive membranes able to control the accumulation of compounds on the surface during filtration, or fouling. Another reason phosphorene is a promising candidate as a membrane material additive is due to its catalytic properties which can potentially destroy foulants on the membrane surface.

The first goal of this study was to develop an innovative and robust membrane able to control and reverse fouling with minimal changes …

Applications Of Drones In Atmospheric Chemistry, Travis J. Schuyler

Theses and Dissertations--Chemistry

The emission of greenhouse gases (GHGs) has changed the composition of the atmosphere during the Anthropocene. A major technical and scientific challenge is quantifying the resulting fugitive trace gas fluxes under variable meteorological conditions. Accurately documenting the sources and magnitude of GHGs emission is an important undertaking for discriminating contributions of different processes to radiative forcing. Therefore, the adverse environmental and health effects of undetected gas leaks motivates new methods of detecting, characterizing, and quantifying plumes of fugitive trace gases. Currently, there is no mobile platform able to quantify trace gases at altitudes(UASs), or drones, can be deployed on-site in …

Synthesis Of Metal Oxide Surface And Interface Arrays By A Combined Solid-Liquid- Vapor/Vapor-Liquid-Solid Approach, Alexandra J. Riddle

Theses and Dissertations--Chemistry

This project was motivated by an in situ heating experiment in the transmission electron microscope (TEM) in which gold (Au) nanoparticles were observed to dissolve tin dioxide (SnO2) nanowires (NWs) under vacuum. The explanation for this observation was that the high-temperature and low-pressure environment of the TEM caused the reverse reaction of the well-known vapor-liquid-solid (VLS) method commonly used to grow NWs. In the VLS process, a metal catalyst absorbs reactant vapor until it becomes supersaturated. The precipitation of the NW occurs at the liquid-solid interface, which ceases when there is no longer reactant vapor, and the diameter of the …

Interfaces In Lead-Free Tin Perovskite Photovoltaics: An Investigation Of Energetics, Ion Mobility, Surface Modification, And Performance, Alex Boehm

Theses and Dissertations--Chemistry

Halide perovskites have generated tremendous interest as low-cost semiconductors for optoelectronics, such as photovoltaics, lasers, and light emitting diodes due to their extraordinary optical and transport properties. Perovskite photovoltaics in particular have demonstrated a meteoric rise in power conversion efficiencies and drawn considerable interest as a next-generation solar energy technology. The rapid development has centered around lead-based derivatives, and concerns regarding the toxicity of lead has sparked interest in low toxicity and more environmentally friendly perovskite derivatives. In this regime tin (Sn) is regarded as a prominent alternative owing to the ideal bandgap and reduced toxicity exhibited by Sn-halide perovskites. …

A Theoretical And Experimental Study Of Charge Transport In Organic Thermoelectric Materials And Charge Transfer States In Organic Photovoltaics, Ashkan Abtahi

Theses and Dissertations--Physics and Astronomy

Applications of organic electronics have increased significantly over the past two decades. Organic semiconductors (OSC) can be used in mechanically flexible devices with potentially lower cost of fabrication than their inorganic counterparts, yet in many cases organic semiconductor-based devices suffer from lower performance and stability. Investigating the doping mechanism, charge transport, and charge transfer in such materials will allow us to address the parameters that limit performance and potentially resolve them. In this dissertation, organic materials are used in three different device structures to investigate charge transport and charge transfer. Chemically doped π-conjugated polymers are promising materials to be used …

Fluorinated Coal Derived Carbons And Electrodes For Use In Battery Systems And Similar, Stephen M. Lipka, Christopher R. Swartz

Center for Applied Energy Research Faculty Patents

An electrode including fluorinated and surface defluorinated coal is described, as well as methods of producing such and employing such within an electrical system. The coal in the electrodes is fluorinated at an amount of between 0.3 and 1 .4. The resulting coal products can be further surface defluorinated and maintain functionality within an electrical system.

Low Temperature Liquid Metal Batteries For Energy Storage Applications, Cameron A. Lippert, Kunlei Liu, James Landon, Susan A. Odom, Nicolas E. Holubowitch

Center for Applied Energy Research Faculty Patents

The present invention relates to a molten metal battery of liquid bismuth and liquid tin electrodes and a eutectic electrolyte. The electrodes may be coaxial and coplanar. The eutectic electrolyte may be in contact with a surface of each electrode. The eutectic electrolyte may comprise ZnC1₂:KCI.

Zirconia-Based Compositions For Use In Passive NoX Adsorber Devices, Deborah Jayne Harris, David Alastair Scapens, John G. Darab, Mark Crocker, Yaying Ji

Chemistry Faculty Patents

A passive NO_x adsorbent includes: palladium, platinum or a mixture thereof and a mixed or composite oxide including the following elements in percentage by weight, expressed in terms of oxide: 10-90% by weight zirconium and 0.1-50% by weight of least one of the following: a transition metal or a lanthanide series element other than Ce.

Although the passive NO_x adsorbent can include Ce in an amount ranging from 0.1 to 20% by weight expressed in terms of oxide, advantages are obtained particularly in the case of low-Ce or a substantially Ce-free passive NO_x adsorbent.

Introducing Phonetic Information To Speaker Embedding For Speaker Verification, Yi Liu, Liang He, Michael T. Johnson

Electrical and Computer Engineering Faculty Publications

Phonetic information is one of the most essential components of a speech signal, playing an important role for many speech processing tasks. However, it is difficult to integrate phonetic information into speaker verification systems since it occurs primarily at the frame level while speaker characteristics typically reside at the segment level. In deep neural network-based speaker verification, existing methods only apply phonetic information to the frame-wise trained speaker embeddings. To improve this weakness, this paper proposes phonetic adaptation and hybrid multi-task learning and further combines these into c-vector and simplified c-vector architectures. Experiments on National Institute of Standards and Technology …

Effect Of Substrate To Inoculum Ratio On Bioenergy Recovery From Food Waste, Yard Waste, And Biosolids By High Solids Anaerobic Digestion, Phillip J. Dixon, Sarina J. Ergas, James R. Mihelcic, Shakira R. Hobbs

Civil Engineering Faculty Publications

Residual biosolids from wastewater treatment facilities and the organic fraction of municipal solid waste (OFMSW), such as food and yard wastes (FW and YW), are difficult to manage due to increased waste generation and recent stringent regulations. This study investigated the effect of substrate to inoculum ratio (S/I) on biochemical transformation mechanisms and biomethane production during high solids anaerobic digestion of FW, YW, and biosolids. Biochemical methane potential (BMP) assays were set up under mesophilic conditions at S/I of 1.0, 2.0, and 3.0 g OFMSW total solids (TS)/g inoculum TS. BMP with the lowest S/I (1.0) produced the highest cumulative …

Overview Of Flywheel Systems For Renewable Energy Storage With A Design Study For High-Speed Axial-Flux Permanent-Magnet Machines, Murat G. Kesgin, Peng Han, Narges Taran, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Flywheel energy storage is considered in this paper for grid integration of renewable energy sources due to its inherent advantages of fast response, long cycle life and flexibility in providing ancillary services to the grid, such as frequency regulation, voltage support, etc. The fundamentals of the technology and recent developments are reviewed, firstly with an emphasis on the design considerations and performance metrics. Then the progress and development trends in electric motor/generators employed in flywheel energy storage systems (FESS) are summarized, showing the potential of axial-flux permanent-magnet (AFPM) machines in such applications. Design examples of high-speed AFPM machines are provided …

Simulated Biological Fluid Exposure Changes Nanoceria’S Surface Properties But Not Its Biological Response, Robert A. Yokel, Matthew L. Hancock, Benjamin Cherian, Alexandra J. Brooks, Marsha L. Ensor, Hemendra J. Vekaria, Patrick G. Sullivan, Eric A. Grulke

Pharmaceutical Sciences Faculty Publications

Nanoscale cerium dioxide (nanoceria) has industrial applications, capitalizing on its catalytic, abrasive, and energy storage properties. It auto-catalytically cycles between Ce³⁺ and Ce⁴⁺, giving it pro-and anti-oxidative properties. The latter mediates beneficial effects in models of diseases that have oxidative stress/inflammation components. Engineered nanoparticles become coated after body fluid exposure, creating a corona, which can greatly influence their fate and effects. Very little has been reported about nanoceria surface changes and biological effects after pulmonary or gastrointestinal fluid exposure. The study objective was to address the hypothesis that simulated biological fluid (SBF) exposure changes nanoceria’s surface properties …

Optimal Combinations Of Utility Level Renewable Generators For A Net Zero Energy Microgrid Considering Different Utility Charge Rates, Evan S. Jones, Huangjie Gong, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

High initial investment and the intermittent nature of resources are major challenges for large scale renewable generation. The size of photovoltaic (PV) and wind turbine (WT) farms in the microgrid needs optimized to avoid curtailment and to efficiently meet the demand of a power system. Battery energy storage systems (BESSs) may also be used to improve flexibility. This paper explores the optimal sizing for PV and wind generators, as well as a BESS at the utility level for a large grid-connected net zero energy (NZE) hybrid microgrid considering characteristics such as initial investment, levelized cost of energy (LCOE), operating costs, …

Smart Plug And Circuit Breaker Technologies For Residential Buildings In The Us, Rosemary E. Alden, Peng Han, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

A significant proportion of the total energy in conventional homes across the United States is used by electric plug loads, which include various electronic devices and home appliances, excluding the heating, ventilation and air conditioning (HVAC) units and electric water heaters. Considerable energy savings are expected to be possible by managing these plug loads effectively based on user behavior data. Smart plugs and circuit breakers that can control and monitor energy usage on a real-time basis are becoming increasingly popular alongside the rapid development of smart home energy management. This paper reviews the recent advances on the subject matter with …

Critical Path For Project Development, Steven Douglas Kreis, Bryan Gibson, Jeff Jasper, Christopher W. Van Dyke, Candice Y. Wallace, Rachel Catchings, Sarah M. Mccormack

Kentucky Transportation Center Research Report

Overseeing the delivery of highway projects at the Kentucky Transportation Cabinet (KYTC) requires the successful coordination of activities and inputs from multiple external agencies and members of the agency’s Project Development team, who have varied disciplinary backgrounds. Despite the complexity of project delivery, the Cabinet presently does not estimate hours and project milestone dates until after it has selected a design consultant. Moving forward KYTC should explore requiring consultants to develop a critical path method (CPM) schedule. To facilitate this process, this report describes a methodology for producing CPMs for design contracts/projects based on procedures outlined in A Guide to …

Post-Acquisition Processing Confounds In Brain Volumetric Quantification Of White Matter Hyperintensities, Ahmed A. Bahrani, Omar M. Al-Janabi, Erin L. Abner, Shoshana H. Bardach, Richard J. Kryscio, Donna M. Wilcock, Charles D. Smith, Gregory A. Jicha

Neurology Faculty Publications

BACKGROUND: Disparate research sites using identical or near-identical magnetic resonance imaging (MRI) acquisition techniques often produce results that demonstrate significant variability regarding volumetric quantification of white matter hyperintensities (WMH) in the aging population. The sources of such variability have not previously been fully explored.

NEW METHOD: 3D FLAIR sequences from a group of randomly selected aged subjects were analyzed to identify sources-of-variability in post-acquisition processing that can be problematic when comparing WMH volumetric data across disparate sites. The methods developed focused on standardizing post-acquisition protocol processing methods to develop a protocol with less than 0.5% inter-rater variance.

RESULTS: A series …

Proppant For Use In Hydraulic Fracturing To Stimulate A Well, Thomas Lee Robl, Anne Elizabeth Oberlink

Center for Applied Energy Research Faculty Patents

A proppant for use in hydraulic fracturing to stimulate a well is provided. The proppant is fly ash particles having a mean particle size (d50) of between 45 μm and 150 μm and a size distribution defined by (d10) ≤ 5 μm and (d98) ≤ 250 μm.

Optimization Of Geometry Parameters Of Inkjet-Printed Silver Nanoparticle Traces On Pdms Substrates Using Response Surface Methodology, Jumana Abu-Khalaf, Loiy Al-Ghussain, Ahmad Nadi, Razan Saraireh, Abdulrahman Rabayah, Safwan Altarazi, Ala’Aldeen Al-Halhouli

Mechanical Engineering Graduate Research

Inkjet printing is an emerging technology with key advantages that make it suitable for the fabrication of stretchable circuits. Specifically, this process is cost-effective and less complex compared to conventional fabrication technologies. Inkjet printing has several process and geometry parameters that significantly affect the electromechanical properties of the printed circuits. This study aims to optimize the geometry parameters of inkjet-printed silver nanoparticle traces on plasma-treated polydimethylsiloxane (PDMS) substrates. The optimization process was conducted for two printed shapes, namely straight line and horseshoe patterns. The examined input factors for the straight line traces were: the number of inkjet-printed layers and line …

Computationally Aided Design Of A High-Performance Organic Semiconductor: The Development Of A Universal Crystal Engineering Core, Anthony J. Petty Ii, Qianxiang Ai, Jeni C. Sorli, Hamna F. Haneef, Geoffrey E. Purdum, Alex M. Boehm, Devin B. Granger, Kaichen Gu, Carla Patricia Lacerda Rubinger, Sean R. Parkin, Kenneth R. Graham, Oana D. Jurchescu, Yueh-Lin Loo, Chad Risko, John E. Anthony

Chemistry Faculty Publications

Herein, we describe the design and synthesis of a suite of molecules based on a benzodithiophene “universal crystal engineering core”. After computationally screening derivatives, a trialkylsilylethyne-based crystal engineering strategy was employed to tailor the crystal packing for use as the active material in an organic field-effect transistor. Electronic structure calculations were undertaken to reveal derivatives that exhibit exceptional potential for high-efficiency hole transport. The promising theoretical properties are reflected in the preliminary device results, with the computationally optimized material showing simple solution processing, enhanced stability, and a maximum hole mobility of 1.6 cm² V⁻¹ s⁻¹.

Systematic Comparison Of Two Axial Flux Pm Machine Topologies: Yokeless And Segmented Armature Versus Single Sided, Narges Taran, Greg Heins, Vandana Rallabandi, Dean Patterson, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

This paper systematically compares two axial flux permanent magnet (AFPM) machines designed for a university student racing car application: a double-rotor single-stator yokeless and segmented armature (YASA) structure, and a single- stator single-rotor configuration. Both machines are optimized for minimum loss and active weight using 3D finite element analysis and the highest performing candidate designs are compared in more detail. The studies indicate that the benefits offered by the YASA configuration over the single-stator single-rotor machine are achieved only for specific designs that are heavier. For the design space with lower mass, albeit with increased losses, the Pareto front designs …

Identification Of Bridges With Fracture-Prone Details, Theodore Hopwood Ii, Rick Younce, Sudhir Palle

Kentucky Transportation Center Research Report

Welded steel girder bridges can contain details that can high welding and service stresses and are termed constraintinduced fractures (CIF). The Kentucky Transportation Cabinet has steel bridges with weld details known to cause CIFs whose girders have experienced fracture events. The Cabinet’s bridge inventory was reviewed and additional candidate bridges with potential CIF details were identified. A review of bridge plans and pictures along with followup field investigations pinpointed bridges with CIF details that warrant up-close (i.e., arm’s length) inspections. Several uninspected bridges were identified as candidates for inspection to determine if they contain CIF details. Guidance is provided to …