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Articles 1 - 22 of 22
Full-Text Articles in Engineering
Mathematical Modeling Of Lithium-Sulfur Batteries, Niloofar Kamyab
Mathematical Modeling Of Lithium-Sulfur Batteries, Niloofar Kamyab
Theses and Dissertations
Energy storage market transformed by utilization of lithium-ion batteries, will demand high and affordable deliverable energy in the near future which it would be impossible for the current employed technologies to meet those needs Among new generation of lithium batteries, high theoretical energy density, good low-temperature performance, and abundance of inexpensive nontoxic raw material, make the lithium-sulfur batteries (LiS) a promising candidate to outperform the current lithium-ion batteries and transform the technology of the future. However, the problems and challenges that LiS batteries are currently facing with, which stem from the inherent complex mechanism of these cells, are hindering their …
Hydrogenation Of Dimethyl Oxalate To Ethylene Glycol Over Silica Supported Copper Catalysts, Xinbin Yu
Hydrogenation Of Dimethyl Oxalate To Ethylene Glycol Over Silica Supported Copper Catalysts, Xinbin Yu
Theses and Dissertations
Ethylene glycol is a bulk chemical and hydrogenation of dimethyl oxalate (DMO) on Cu/SiO2 catalysts is the final reaction step in a growing industrial syngas to ethylene glycol (StEG) process. Efforts to improve the performance of the catalysts are still ongoing and the detailed catalytic mechanism remains controversial.
In the present work, a series of 10 wt% Cu/SiO2 is prepared.by urea hydrolysis method and indium species is introduced by incipient wetness impregnation. Reaction studies show that 0.25 wt%-0.5 wt% of indium species can dramatically enhance the performance of 10 wt% Cu/SiO2 catalyst. Various characterizations reveal that indium species …
Volume Frequency Response Method For Determining Mass Transfer Mechanisms Of O2 In Carbon Molecular Sieve 3k172, Olivia Smithson
Volume Frequency Response Method For Determining Mass Transfer Mechanisms Of O2 In Carbon Molecular Sieve 3k172, Olivia Smithson
Theses and Dissertations
Carbon molecular sieves (CMS) have grown more desirable over the years as an adsorbent for industrial separation processes as CMS technology has advanced. CMS is commonly used in nitrogen inerting (i.e, oxygen removal from air), carbon dioxide removal from methane and oxygen purification. However, knowledge of the dynamic behavior of these gases on CMS is needed to design and operate efficient and effective separation processes. For this reason, the mass transfer resistances within the micropore at both low and high frequencies were characterized using frequency response, COMSOL Multiphysics modeling, and MATLAB optimization , because frequency response methods have demonstrated the …
Epoxy-Functional Thermoplastic Copolymers And Their Incorporation Into Thermosetting Resins, Kayla Rose Sweet
Epoxy-Functional Thermoplastic Copolymers And Their Incorporation Into Thermosetting Resins, Kayla Rose Sweet
Theses and Dissertations
While polymers have secured a place in the consumer, industrial, and military markets over the last seventy years, the next generation of polymers must become more renewable, more adaptive, and higher performing to bridge industrial needs and environmental gaps. To this end, unique network configurations of copolymers and interpenetrating polymer networks (IPNs) have been employed to combine features of two or more polymers into a single material that surpasses the sum of its parts. The customization of polymer networks can be made possible via dual-functional monomers, molecules characterized by two different reactive substituents that allow for versatile methods of polymerization. …
Synthesis And Characterization Of Thermosetting Epoxy Resins From Lignin-Inspired Phenolics, Kelli Marie Hambleton
Synthesis And Characterization Of Thermosetting Epoxy Resins From Lignin-Inspired Phenolics, Kelli Marie Hambleton
Theses and Dissertations
The need for renewable polymers able to replace their petrochemical counterparts continues to grow as sustainability concerns constantly rise. Bisguaiacol, a bio-based alternative to bisphenol-A, has been synthesized using vanillyl alcohol and guaiacol via an electrophilic aromatic condensation. Purification provides both bisguaiacol and an oligomeric coproduct with a consistent number average molecular weight and dispersity of about 650 Da and 1.00, respectively, across multiple reaction volume scales. This coproduct has been well characterized as a low molecular weight novolac averaging 5 hydroxyls per molecule and was transformed into an epoxy resin suitable for use in thermosetting resin development. By utilizing …
Solid Materials Discovery For Thin Films, Oxide Catalysts, And Polymer Sealants, Benjamin Ruiz-Yi
Solid Materials Discovery For Thin Films, Oxide Catalysts, And Polymer Sealants, Benjamin Ruiz-Yi
Theses and Dissertations
Solid materials are made up of multiple classes, including metals, ceramics, and polymers. While each class can be developed for general purpose applications or highly specialized, discovery of new materials in order to improve upon desired properties is a non-trivial task for any type of material. A wide variety of materials encompass expansive design spaces, consisting of parameters such as chemical compositions, synthesis conditions, and post-processing. Due to this, narrowing down the design space to fit within a given figure-of-merit and economic viability becomes time consuming at best and infeasible at worst. High-throughput experimentation
High-throughput experimentation (HTE) is a methodology …
Fundamental Studies Of Oxygen Electrocatalysis In Alkaline Electrochemical Cells, Victoria F. Mattick
Fundamental Studies Of Oxygen Electrocatalysis In Alkaline Electrochemical Cells, Victoria F. Mattick
Theses and Dissertations
Until recently the world’s main source of energy has been fossil fuels, such as coal and petroleum. However, these energy sources are polluting our planet, becoming scarce and increasingly inaccessible, and are costly to extract. Therefore, much attention has been directed to harvesting clean, abundant, and renewable energy, such as solar rays and wind. However, the intermittency of solar and wind power generation requires an effective energy buffering solution (aka energy storage) to become efficient and reliable. With high efficiency and energy density, rechargeable batteries and reversible fuel cells are two of the best methods for this purpose. Unfortunately, a …
Investigation Of Oxidized Carbon Supported Au Catalysts Synthesized Via Strong Electrostatic Adsorption Of Au(En)2Cl3 For The Hydrochlorination Of Acetylene To Vinyl Chloride Monomer, Sean Reginald Noble
Investigation Of Oxidized Carbon Supported Au Catalysts Synthesized Via Strong Electrostatic Adsorption Of Au(En)2Cl3 For The Hydrochlorination Of Acetylene To Vinyl Chloride Monomer, Sean Reginald Noble
Theses and Dissertations
Over 20 million tons of vinyl chloride monomer (VCM) is produced every year using acetylene hydrochlorination using a supported mercuric chloride catalyst. During this process mercury is reduced and sublimes into the environment harming all living animals and humans, so carbon-supported Au catalysts have been developed in attempts to replace it. Various techniques have been used to make these catalysts including several variations of dry impregnation. In this study we investigate the ability of Strong Electrostatic Adsorption (SEA) of Au(en)2Cl3 onto various supports to demonstrate the ability to rationally and consistently synthesize gold catalysts with ultra-small particle …
Theoretical Investigation Of The Biomass Conversion On Transition Metal Surfaces Based On Density Functional Theory Calculations And Machine Learning, Wenqiang Yang
Theses and Dissertations
During the past decades, heterogenous catalyzed conversion of biomass to hydrocarbons with similar or identical properties to conventional fossil fuels has gained significantly academic and industrial interest. However, the conventional heterogeneous catalysts such as sulfided NiMo/Al2O3 and CoMo/Al2O3 used have various drawbacks, such as short catalyst lifetime and high sulfur content of product. To overcome the limitations of the conventional sulfided catalysts, new catalysts must be developed, which requires a better understanding of the reaction mechanism of the biomass conversion. Based on density functional theory, in this thesis, we reported a computational calculation study …
Bijels Made By Solvent Transfer Induced Phase Separation: Formation Principles And Transport, Stephen Boakye-Ansah
Bijels Made By Solvent Transfer Induced Phase Separation: Formation Principles And Transport, Stephen Boakye-Ansah
Theses and Dissertations
Bijels are made of non-equilibrium particle-stabilized emulsions with a bicontinuous arrangement of the constituent fluid phases. They spontaneously form through arrested spinodal decomposition in mixtures of partially miscible liquids and neutrally wetting colloidal particles. Soon after their discovery over 10 years ago, Prof. Mike Cates, Lucasian Professor of Mathematics, predicted their future use as continuously operated cross-flow reactors for chemical reactions between immiscible reactants.
Towards this goal, work in this thesis focuses on designing bijels via Solvent Transfer Induced Phase Separation (STrIPS) for microfluidic transport applications. Structure-function relationships of STrIPS bijels stabilized by silane functionalized nanoparticles are developed. In-situ surfactant …
Study And Characterization Of Conductive Elastomers For Biomedical Applications, Hadis Gharacheh
Study And Characterization Of Conductive Elastomers For Biomedical Applications, Hadis Gharacheh
Theses and Dissertations
Health issues have always been one of humankind's biggest challenges. Over the last century, there has been significant and monumental progress in health and biomedical science, with the end goal of alleviating and eliminating illnesses and ailments. For developing biomedical devices, polymers and elastomers group among other types of biomaterials have been highlighted to be used due to high flexibility, stability, biocompatibility, and mechanical and rheological characteristics. In this work, the characterization of acrylated poly glycerol_sebacate (PGSA) polymer conjugated with bio ionic liquid (BIL) was investigated. Results showed high biocompatibility, high printability with tunable mechanical, adhesive, and conductivity properties. For …
Synthesis And Evaluation Of Catalytic Application Of Porous Resin, Mahboubeh Nabavinia
Synthesis And Evaluation Of Catalytic Application Of Porous Resin, Mahboubeh Nabavinia
Theses and Dissertations
The abilities to tailor catalytic functional groups and chemical characteristics onto a robust polymer structure make mesoporous phenolic resins great candidates for catalytic support applications. The use of a template synthesis method for configuring a catalytic structure is neither commercially nor environmentally friendly. In this Ph.D. thesis, new one-pot template-free methods for synthesizing mesoporous metal-doped phenol-formaldehyderesin were developed. The methods facilitate scaling for industrial catalytic applications in pharmaceutical, environmental, and medical applications. Heterogeneous palladium centered catalytic mesoporous structures were synthesized by a single-stage template-free method. BET adsorption measurements, SEM, EDX, XPS, and TEM were used to study the surface area, …
The Development Of Polymer Constructs For Adipose Tissue Engineering Applications, Kendall Murphy
The Development Of Polymer Constructs For Adipose Tissue Engineering Applications, Kendall Murphy
Theses and Dissertations
The adipose tissue functions as the body’s main energy reservoir and plays a central role in maintaining whole body energy homeostasis. The ability to modulate this tissue’s inherent endocrine and metabolic functions has promising implications in treating disease associated with adipose tissue dysfunction. This work revolves around two diseases where adipose tissue inflammation and metabolic dysfunction drive the disease, obesity and cachexia. Both diseases impact a significant population of U.S. adults and substantially reduce patient quality of life.
In this study, we first demonstrate the use of novel therapeutic platforms engineered to specifically target adipose tissue inflammation and lipid catabolism …
Influence Of Coordination Environment On Catalyst Structure And Function For Co2 Hydrogenation And Ethane Partial Oxidation, Juan D. Jimenez
Influence Of Coordination Environment On Catalyst Structure And Function For Co2 Hydrogenation And Ethane Partial Oxidation, Juan D. Jimenez
Theses and Dissertations
In this work, we set out to establish strong structure/activity relationships for various catalytic compositions and reactions. Through in situ spectroscopic approaches, specifically DRIFTS, Raman XPS, and XAFS, we were able to discern the reactive species in CO2 hydrogenation over highly active cobalt nanostructures, the relevant ensemble size and composition of single site catalysts for CO2 hydrogenation, and active vibrational modes of mixed oxide catalysts for ethane partial oxidation (EPO).
First, we illustrate how tailoring surface orientations of Co3O4 catalysts on the nanoscale results in control over catalytic performance via the preferential formation of active …
Multi-Scale Modeling For Transport Study Inside Porous Layers Of Polymer Electrolyte Membrane Fuel Cell Using Direct Numerical Simulation, Pongsarun Satjaritanun
Multi-Scale Modeling For Transport Study Inside Porous Layers Of Polymer Electrolyte Membrane Fuel Cell Using Direct Numerical Simulation, Pongsarun Satjaritanun
Theses and Dissertations
The direct modeling-based Lattice Boltzmann Agglomeration Method (LBAM) is used to explore the electrochemical kinetics and multi-scalar/multi-physics transport inside the detailed structure of the porous and catalyst layers inside polymer electrolyte membrane fuel cells (PEMFCs). The complete structure of the samples is obtained by both micro- and nano- X-ray computed tomography (CT). LBAM is able to predict the electrochemical kinetics in the nanoscale catalyst layer and investigate the electrochemical variables during cell operation. This work shows success in integrating the lattice elements into an agglomerate structure in the catalyst layer (CL). The predictions using LBAM were compared and validated with …
Hybrid Monomers & Resins For High-Performance Thermosetting Polymers, Thermoplastics, & Additive Manufacturing, Alexander William Bassett
Hybrid Monomers & Resins For High-Performance Thermosetting Polymers, Thermoplastics, & Additive Manufacturing, Alexander William Bassett
Theses and Dissertations
Vinyl ester and epoxy resins are used to produce thermosetting polymeric materials for a variety of commercial and military applications due to their relatively high moduli (2-3 GPa at 25 deg C), glass transition temperatures (Tgs) (greater than or equal to 120 deg C), and adequate fracture toughness (G1C approx. 200-250 J m-2). Most commercially available vinyl ester and epoxy resins are typically cured via traditional manufacturing techniques such as resin transfer molding and thermal curing. However, additive manufacturing (AM) has gained significant traction as a favorable manufacturing technique over traditional methods due to the ability to create customizable parts …
Application Of Immobilized Palladium Monolithic Catalysts In Suzuki-Miyaura And Tsuji-Wacker Redox Reactions, Sajjad Ghobadi
Application Of Immobilized Palladium Monolithic Catalysts In Suzuki-Miyaura And Tsuji-Wacker Redox Reactions, Sajjad Ghobadi
Theses and Dissertations
Herein, a wholistic analysis of the viability of monolithic catalysts for redox reactions is presented. The interdisciplinary approach taken in this systematic study included preparation and investigation on Pd-on-carbon monoliths as catalysts in a flow and electrochemical settings.
The Suzuki-Miyaura reaction-focused study led to rational design, preparation, and successful application of Pd0-on-graphene oxide (GO) monolithic catalysts in flow conditions. In this study a combination of chemical reduction, freeze-casting, and vapor-phase reduction processes was applied to Pd-GO structures leading to the preparation of these monoliths. The Suzuki flow synthesis reactions revealed that the monolithic structure led to significantly improved …
Beneficiation Of Coal Using Supercritical Water And Carbon Dioxide Extraction, Matthew Decuir Virginia Commonwealth University Cl
Beneficiation Of Coal Using Supercritical Water And Carbon Dioxide Extraction, Matthew Decuir Virginia Commonwealth University Cl
Theses and Dissertations
This work explores the use of carbon dioxide, water, and their mixtures as solvent for the pre-combustion beneficiation of raw coal without using any toxic mineral acids in the temperature range of 200-400℃. The fluid polarity, ionic constant, and supercritical point can be adjusted by H2O/CO2 ratio and temperature. Adding carbon dioxide to hydrothermal fluid also increases the ionization by forming carbonic acid. Extractions with supercritical fluids have several benefits including enhanced mass transport, ease of separation and recycle, wide range of extractive capability and tunability, better inherent safety, and in the case of carbon dioxide and …
Self-Assembled Metal Nanoparticle/Polymer Nanocomposites As Nanoreactors For One-Pot Reactions, Andrew Harrison
Self-Assembled Metal Nanoparticle/Polymer Nanocomposites As Nanoreactors For One-Pot Reactions, Andrew Harrison
Theses and Dissertations
Polymer nanoreactors incorporating gold nanoparticle catalysts were self-assembled via Flash Nanoprecipitation. The incorporated gold nanoparticles maintained catalytic activity, which was evaluated using reduction of 4-nitrophenol with sodium borohydride as a model reaction. The diffusion coefficient for 4-nitrophenol was determined by NMR and used to calculate the second Damköhler number, which indicated that the systems were not diffusion limited. Despite similar diffusion coefficients, catalytic performance was strongly affected by the co-precipitant. For example, the apparent reaction rate per surface area using castor oil was over 8-fold greater than polystyrene. Thus, we measured the partition coefficient of 4-nitrophenol between water and castor …
Higher Tensile Forces Across Cellular Junctions And An Intact Nuclear Linc Complex Is Required For Epithelial Function And Stability, Fnu Vani Narayanan
Higher Tensile Forces Across Cellular Junctions And An Intact Nuclear Linc Complex Is Required For Epithelial Function And Stability, Fnu Vani Narayanan
Theses and Dissertations
Recent advances in three-dimensional (3D) cell culture systems have provided key insights into the understanding of biochemical and physiological states of native tissue. A significant progress in the field of mechanobiology involves measuring cellular traction forces in a more native 3D environment. However, the effects of mechanical forces exerted across cellular junctions and the nuclear LINC complex, in an organized 3D system has not been investigated thus far. Epithelial cells spontaneously form acini (also known as cysts or spheroids) with a single, fluid-filled central lumen, when grown in 3D matrices. The size of the lumen is dependent on apical secretion …
Formulation And Validation Of Nanoparticle Controlled Delivery For Chemotherapeutic Drug Products, Shani L. Levit
Formulation And Validation Of Nanoparticle Controlled Delivery For Chemotherapeutic Drug Products, Shani L. Levit
Theses and Dissertations
Taxol, a formulation of paclitaxel (PTX), is one of the most widely used anticancer drugs, particularly for treating recurring ovarian carcinomas following surgery. Clinically, PTX is used in combination with other drugs such as lapatinib (LAP) to increase treatment efficacy. Delivering drug combinations with nanoparticles has the potential to improve chemotherapy outcomes. In this study, we use Flash NanoPrecipitation, a rapid, scalable process to encapsulate weakly hydrophobic drugs (logP in vitro. Encapsulating either PTX or LAP into nanoparticles increases drug potency. When PTX and LAP are co-loaded in the same nanoparticle, they have a synergistic effect that is greater than …
Reaction Profiling Of Extracellular Protein Phosphorylation Through A Microfluidic Reactor Coupled With Raman Spectroscopy, Abigail Casey
Reaction Profiling Of Extracellular Protein Phosphorylation Through A Microfluidic Reactor Coupled With Raman Spectroscopy, Abigail Casey
Theses and Dissertations
Diseases and disorders in the human body are considered abnormalities of proper cellular function. Understanding the signal transduction mechanisms that cause these abnormalities is crucial to developing earlier detection methods, better treatment options and effective cures. While current diagnostic procedures are powerful tools in diagnosing diseases, they are ineffective in informing physicians on the real-time behavior of the signal transduction mechanisms associated with diseases and disorders. Currently, disease progression is monitored over time through routine patient visits and testing by one or more of the above techniques. By developing an approach that can monitor structural and conformational changes of proteins …