Chemical Engineering Commons^™

Galvanic Corrosion Of Magnesium Coupled To Steel At High Cathode-To-Anode Area Ratios, Dila Ram Banjade

Theses and Dissertations

In this study, the impact of galvanic coupling of magnesium to steel on the corrosion rate, surface morphology, and surface film formation was investigated. In particular, the role of self-corrosion was quantified as previous studies showed discrepancies between model predictions and experimental results that were likely due to significant self-corrosion. This experimental study examined the corrosion of Mg coupled to steel in 5 wt% NaCl at cathode-to-anode area ratios that ranged from 5 to 27. Results showed that self-corrosion was significant and accounted for, on average, one-third of total corrosion. Moreover, self-corrosion varied with time and cathode size, and was …

Lignin-Derived Thermosetting Vinyl Ester Resins For High Performance Applications, Daniel Rogers

Theses and Dissertations

Vinyl ester (VE) resins are utilized to produce polymer matrix composites for use in a wide range of applications due to possessing relatively high moduli, strengths, and glass transition temperatures while maintaining low weight and cost. VE resins often contain high concentrations of a petroleum-based reactive diluent (RD), such as styrene. Many of the commonly used RDs have been designated as hazardous air pollutants, potential carcinogens, and volatile organic compounds. Renewable VE resins and RDs with similar performance to petroleum-based RDs are desired to potentially mitigate the aforementioned hazards as well as to facilitate the transition from petrochemical feedstocks to …

An Improved Dynamic Particle Packing Model For Prediction Of The Microstructure In Porous Electrodes, Chien-Wei Chao

Theses and Dissertations

The goal of this work is to develop a model to predict the microstructure of Li-ion batteries, specifically focusing on the cathode component of the batteries. This kind of model has the potential to assist researchers and battery manufacturers who are trying to optimize the capacity, cycle life, and safety of batteries. Two dynamic particle packing (DPP) microstructure models were developed in this work. The first is the DPP1 model, which simulates the final or dried electrode structure by moving spherical particles under periodic boundaries using Newton's laws of motion. The experience derived from developing DPP1 model was beneficial in …

Synthesis And Characterization Of Vanillyl Alcohol Based Thermosetting Epoxy Resins, Eric Hernandez

Theses and Dissertations

Lignin is a natural and abundant renewable material composed of crosslinked phenylpropenyl units that when strategically depolymerized could potentially yield renewable bio-based aromatic building blocks for applications in high-performance thermosetting epoxy resins. Vanillyl alcohol, a lignin derived aromatic diol, is a potential platform chemical for the production of renewable bisphenols and epoxy thermosets. A new bio-based bisphenol (bisguaiacol) was synthesized via electrophilic aromatic condensation of vanillyl alcohol and guaiacol, from which diglycidyl ether of bisguaiacol (DGEBG) was prepared via epoxidation with epichlorohydrin.The thermomechanical properties of DGEBG blended with a commercial BPA-based epoxy resin and cured with a diamine were investigated …

A Mathematical Model Of A Control Systems Hypothesis Of N-Methyl-D-Aspartate-Receptor-Mediated Ethanol Dependence And Withdrawal Dynamics, Carlos Gutierrez

Theses and Dissertations

The biochemical effects of ethanol on the human brain are manifested through many neurological pathways. Chronic exposure to the depressant has been shown to result in physical dependence. Subsequent cessation results in withdrawal symptoms such as seizures and both short- and long-term changes in neurological activity. One of the primary conduits implicated in the pathways of ethanol dependence and withdrawal is the detection of glutamate via N-methyl-D-aspartate (NMDA) receptors (NMDARs). Ethanol molecules inhibit these receptors, and consequent NMDA-induced glutamatergic changes can result in dependence on ethanol in order to sustain normal brain function. This study considers the relocation control of …

The Performance Of Structured High-Capacity Si Anodes For Lithium-Ion Batteries, Jui Chin Fan

Theses and Dissertations

This study sought to improve the performance of Si-based anodes through the use of hierarchically structured electrodes to provide the nanoscale framework needed to accommodate large volume changes while controlling the interfacial area – which affects solid-electrolyte interphase (SEI) formation. To accomplish this, electrodes were fabricated from vertically aligned carbon nanotubes (VACNT) infiltrated with silicon. On the nanoscale, these electrodes allowed us to adjust the surface area, tube diameter, and silicon layer thickness. On the micro-scale, we have the ability to control the electrode thickness and the incorporation of micro-sized features. Treatment of the interfacial area between the electrolyte and …

The Effect Of Microstructure On Transport Properties Of Porous Electrodes, Serena Wen Peterson

Theses and Dissertations

The goal of this work is to further understand the relationships between porous electrode microstructure and mass transport properties. This understanding allows us to predict and improve cell performance from fundamental principles. The investigated battery systems are the widely used rechargeable Li-ion battery and the non-rechargeable alkaline battery. This work includes three main contributions in the battery field listed below.

Direct Measurement of Effective Electronic Transport in Porous Li-ion Electrodes. An accurate assessment of the electronic conductivity of electrodes is necessary for understanding and optimizing battery performance. The bulk electronic conductivity of porous LiCoO2-based cathodes was measured as a …

Nonlinear Estimation And Control With Application To Upstream Processes, Reza Asgharzadeh Shishavan

Theses and Dissertations

Subsea development and production of hydrocarbons is challenging due to remote andharsh conditions. Recent technology development with high speed communication to subsea anddownhole equipment has created a new opportunity to both monitor and control abnormal or undesirableevents with a proactive and preventative approach rather than a reactive approach. Twospecific technology developments are high speed, long-distance fiber optic sensing for productionand completion systems and wired pipe for drilling communications. Both of these communicationsystems offer unprecedented high speed and accurate sensing of equipment and processes that aresusceptible to uncontrolled well situations, leaks, issues with flow assurance, structural integrity,and platform stability, as well …

Energy Process Enabled By Cryogenic Carbon Capture, Mark Jensen

Theses and Dissertations

Global climate change concerns help shape current environmental regulations, which increasingly seek to reduce or capture CO2 emissions. Methods for capturing CO2 emissions from energy processes have been the focus of numerous studies to provide support for those seeking to reduce the environmental impact of their processes. This research has (1) simulated a baseline case of energy-storing cryogenic carbon capture for implementation on a 550 MWe coal fired power plant, (2) presented a novel cryogenic carbon capture process for removing CO2 from natural gas down to arbitrary levels, (3) presented a natural gas liquefaction process that has the ability to …

Selective Synthesis And Characterization Of Single-Site Hy Zeolite-Supported Rhodium Complexes And Their Use As Catalysts For Ethylene Hydrogenation And Dimerization, Konstantin Khivantsev

Theses and Dissertations

Single-site Rh(CO)2, Rh(C2H4)2 and Rh(NO)2 complexes anchored on various dealuminated HY zeolites can be used as precursors for the selective surface mediated synthesis of well-defined site-isolated Rh(CO)(H)x complexes. DFT calculations and D2 isotope exchange experiments provide strong evidence for the formation of a family of site isolated mononuclear rhodium carbonyl hydride complexes (including the first examples of RhH complexes with undissociated H2 ligands): Rh(CO)(H2), Rh(CO)(H)2, and Rh(CO)(H). The fraction of each individual complex formed varies significantly with the Si/Al ratio of the zeolite and the nature of the precursor used.

HY zeolite-supported mononuclear Rh(CO)2 complexes are remarkably active in ethylene …

Engineered 3d Microenvironments To Direct Osteogenic Differentiation And Modulate Inflammation, Katherine Elizabeth Rutledge

Theses and Dissertations

Current methods of treating critical size bone defects (CSDs) include autografts and allografts, however both present major limitations including donor-site morbidity, risk of disease transmission, and immune-rejection. Tissue engineering provides a promising alternative to circumvent these shortcomings through the use of stem cells, three dimensional (3D) scaffolds, and growth factors. Cells receive signals from their microenvironment that determine cell phenotype, and a combination of physical cues and chemical factors is thought to have the most profound influence on stem cell behavior. A major focus of tissue engineering strategies is scaffold design to recapitulate in vivo microenvironmental architecture to direct stem …

Integrated Nanoscale Imaging And Spatial Recognition Of Biomolecules On Surfaces, Congzhou Wang

Theses and Dissertations

Biomolecules on cell surfaces play critical roles in diverse biological and physiological processes. However, conventional bulk scale techniques are unable to clarify the density and distribution of specific biomolecules in situ on single, living cell surfaces at the micro or nanoscale. In this work, a single cell analysis technique based on Atomic Force Microscopy (AFM) is developed to spatially identify biomolecules and characterize nanomechanical properties on single cell surfaces. The unique advantage of these AFM-based techniques lies in the ability to operate in situ (in a non-destructive fashion) and in real time, under physiological conditions or controlled micro-environments.

First, AFM-based …

Designed Synthesis Of Nanoporous Organic Polymers For Selective Gas Uptake And Catalytic Applications, Pezhman Arab

Theses and Dissertations

Design and synthesis of porous organic polymers have attracted considerable attentions during the past decade due to their wide range of applications in gas storage, gas separation, energy conversion, and catalysis. Porous organic polymers can be pre-synthetically and post-synthetically functionalized with a wide variety of functionalities for desirable applications. Along these pursuits, we introduced new synthetic strategies for preparation of porous organic polymers for selective CO₂ capture.

Porous azo-linked polymers (ALPs) were synthesized by an oxidative reaction of amine-based monomers using copper(I) as a catalyst which leads to azo-linkage formation. ALPs exhibit high surface areas of up to 1200 …

Multi-Platform Arabinoxylan Scaffolds As Potential Wound Dressing Materials, Donald C. Aduba Jr

Theses and Dissertations

Biopolymers are becoming more attractive as advanced wound dressings because of their naturally derived origin, abundance, low cost and high compatibility with the wound environment. Arabinoxylan (AX) is a class of polysaccharide polymers derived from cereal grains that are primarily used in food products and cosmetic additives. Its application as a wound dressing material has yet to be realized. In this two-pronged project, arabinoxylan ferulate (AXF) was fabricated into electrospun fibers and gel foams to be evaluated as platforms for wound dressing materials. In the first study, AXF was electrospun with varying amounts of gelatin. In the second study, AXF …

The Synthesis Of Solid Supported Palladium Nanoparticles: Effective Catalysts For Batch And Continuous Cross Coupling Reactions, Kendra W. Brinkley

Theses and Dissertations

Catalysis is one of the pillars of the chemical industry. While the use of catalyst is typically recognized in the automobile industry, their impact is more widespread as; catalysts are used in the synthesis of 80% of the US commercial chemicals. Despite the improved selectivity provided by catalyst, process inefficiencies still threaten the sustainability of a number of synthesis methods, especially in the pharmaceutical industry. Recyclable solid supported catalysts offer a unique opportunity to address these inefficiencies. Such systems coupled with continuous synthesis techniques, have the potential to significantly reduce the waste to desired product ratio (E-factor) of the production …

Measurements And Modeling Of Hydrocarbon Mixture Fluid Properties Under Extreme Temperature And Pressure Conditions, Babatunde A. Bamgbade

Theses and Dissertations

Knowledge of thermodynamic fluid properties, such as density and phase behavior, is important for the design, operation, and safety of several processes including drilling, extraction, transportation, and separation that are required in the petroleum. The knowledge is even more critical at extreme temperature and pressure conditions as the search for more crude oil reserves lead to harsher conditions. Currently, there is dearth of experimental data at these conditions and as such, the predictive capability of the existing modeling tools are unproven. The objective of this research is to develop a fundamental understanding of the impact of molecular architecture on fluid …

Polysaccharide-Based Shear Thinning Hydrogels For Three-Dimensional Cell Culture, Vasudha Surampudi

Theses and Dissertations

The recreation of the complicated tissue microenvironment is essential to reduce the gap between in vitro and in vivo research. Polysaccharide-based hydrogels form excellent scaffolds to allow for three-dimensional cell culture owing to the favorable properties such as capability to absorb large amount of water when immersed in biological fluids, ability to form “smart hydrogels” by being shear-thinning and thixotropic, and eliciting minimum immunological response from the host. In this study, the biodegradable shear-thinning polysaccharide, gellan-gum based hydrogel was investigated for the conditions and concentrations in which it can be applied for the adhesion, propagation and assembly of different mammalian …

Novel Biofabrication Technologies To Recapitulate In Vivo Geometries In Collagen Hydrogels, Veronica Rodriguez-Rivera

Theses and Dissertations

Tissue engineering and regenerative medicine aims to restore form and function to tissues that have been lost or damaged due to disease, congenital defect, or trauma. Biomaterials suitable to restore these complex tissues need to provide a balance between chemical and mechanical properties, providing accurate cell-matrix interaction and induce in vivo behaviors such as proliferation, differentiation and migration. It also requires that physical and chemical cues be presented to the body in the proper temporal and spatial pattern. The extracellular matrix exerts forces that are transmitted through focal adhesion causing changes in the cell behavior. The hypothesis for this dissertation …

Surface Modification Of Nanoplatelets In Polymer Nanocomposites, Shailesh K. Shori

Theses and Dissertations

In polymer nanocomposites (PNCs), it is very important that the nanofiller (typically an inorganic) is well-dispersed in an organic polymer matrix. Optimal compatibility results in end-use products such as packaging materials with enhanced properties. In practice, however, this is challenging to achieve because “ideal” dispersions require the complete uniform separation, termed exfoliation, of the nanofiller within the matrix. As a result, different nanofillers including calcium niobate (CN) and montmorillonite (MMT) are first studied for their ability to exfoliate in aqueous suspensions by measuring the organic cation uptake. The cation exchange capacity, or CEC, determined that CN needs further work before …

A Three-Dimensional-Engineered Matrix To Study The Microenvironment Of Cancer Stem Cells, Samaneh Kamali Sarvestani

Theses and Dissertations

Maintenance of cancer stem cells (CSCs) is regulated by their microenvironment. As cancer cells are affected by many factors in their microenvironment, a major challenge is to isolate the effect of a specific factor on CSCs while keeping other factors unchanged. We developed a synthetic inert 3D Poly Ethylene Glycol Di-Acrylate (PEGDA) gel culture system as a unique tool to study the effect of microenvironmental factors on CSCs response. Synthetic hydrogels provide the flexibility to design three-dimensional (3D) matrices to isolate and study individual factors in the tumor microenvironment. The first objective of this work was to investigate the effect …

Bio-Active Degradable Micellar Hydrogels For Osteogenic Differentiation Of Mesenchymal Stem Cells, Seyedsina Moeinzadeh

Theses and Dissertations

A feasible approach to the restoration of injured bone tissue is the use of tissue engineering strategies to deliver mesenchymal stem cells (MSCs) to the site of regenration in degradable, in-situ gelling, bio-active hydrogels. Although inert Polyethylene glycol (PEG) hydrogels provide flexibility in controlling the cell microenvironment, their use for in vivo applications in tissue regeneration is limited by their persistence (nondegradability) in the site of regeneration. In an attempt to produce inert hydrolytically degradable matrices for encapsulation of MSCs, hydrogels based on star PEG macromonomers chain-extended with short hydroxy acid (HA) segments (SPEXA) were synthesized and characterized with respect …

Theoretical Investigation Of The Catalytic, Liquid-Phase Hydrodeoxygenation Of Organic Acids And Esters, Sina Behtash

Theses and Dissertations

With worldwide fossil fuel resources dwindling and greenhouse gas emissions rising, it is urgent to find renewable liquid fuel alternatives from e.g. biomass to meet the world’s growing energy demand. Lipid feedstocks and pyrolysis oils from woody biomass can be utilized for the production of second-generation biofuels via a catalytic hydrodeoxygenation (HDO) process. The conversion of fatty acids and esters plays an important role in the activity and selectivity of these processes. Understanding the HDO reaction mechanism of organic acids and esters on metal surfaces is a prerequisite for the rational design of new HDO catalysts specifically designed for upgrading …

Quantifying Individual Losses In A Direct Methanol Fuel Cell, Jennifer Rae Ruffing

Theses and Dissertations

The performance of a direct methanol fuel cell (DMFC) is complicated due to the complex interactions of kinetic and transport processes. As a result, changes in one aspect of the cell have consequences in other aspects, which are difficult to elucidate from the full-cell polarization (i.e. voltage vs. current) behavior that fuel cell researchers often use to characterize the performance of their systems. The objective of this work was to develop a strategy to use current and voltage relationships from anode half cells, cathode half-cells, and a hydrogen pump, coupled with methanol crossover data and a mathematical model, to quantify …

Synthesis Of Au And Ag Catalysts With Controlled Sizes Of Metal Particles, Eleni A. Kyriakidou

Theses and Dissertations

The performance of supported metal catalysts largely depends on the structure and composition of the metal particles and the nature of the support. In order to achieve better control over these parameters, synthetic route based on the use of templating agents has been proposed. Among the different templating agents, poly(amidoamine) (PAMAM) dendrimers have attracted a lot of recent attention as nanoparticle stabilizers. In this thesis, Au/G4OH nanocomposites were synthesized in aqueous solutions and used as precursors for the preparation of SiO2-supported Au nanoparticles. Elemental analysis, UV-Vis, and STEM measurements were used to estimate the extent of the Au-dendrimer interactions and …

Kinetic Experimental And Modeling Studies On Iron-Based Catalysts Promoted With Lanthana For The High-Temperature Water-Gas Shift Reaction Characterized With Operando Uv-Visible Spectroscopy And For The Fischer-Tropsch Synthesis, Basseem Bishara Hallac

Theses and Dissertations

The structural and functional roles of lanthana in unsupported iron-based catalysts for the high-temperature water-gas shift reaction and Fischer-Tropsch synthesis were investigated. The performance of the catalysts with varying lanthana contents was based on their activity, selectivity, and stability. With regard to the former reaction, extent of reduction of the iron in Fe2O3/Cr2O3/CuO/La2O3 water-gas shift catalysts is a key parameter that was characterized using UV-visible spectroscopy. Minor addition of lanthana (<0.5 wt%) produces more active and stable catalysts apparently because it stabilizes the iron-chromium spinel, increases the surface area of the reduced catalysts, enhances the reduction of hematite to the magnetite active phase, and facilitates the adsorption of CO on the surface of the catalyst modeled by an adsorptive Langmuir-Hinshelwood mechanism. Statistical 95% confidence contour plots of the adsorption equilibrium constants show that water adsorbs more strongly than CO, which inhibits the reaction rate. A calibration curve that correlates the oxidation state of surface iron domains to normalized absorbance of visible light was successfully generated and applied to the water-gas shift catalysts. UV-visible studies indicated higher extent of reduction for surface Fe domains for the catalysts promoted with 1 wt% of lanthana and showed potential to be a more convenient technique for surface chemistry studies than X-ray absorption near edge spectroscopy (XANES). Lanthana addition to iron-based Fischer-Tropsch catalysts enhances the olefin-to-paraffin ratio, but decreases their activity, stability, and selectivity to liquid hydrocarbons. Adding lanthana at the expense of potassium reduces the water-gas shift selectivity and enhances the activity and stability of the catalysts. Finally, a model that simulates heat and mass transfer limitations on the particle scale for the Fischer-Tropsch reaction applicable at lab-scale suggests optimal operating and design conditions of 256°C, 30 bar, and 80 mirons are recommended for higher selectivity to liquid hydrocarbons. The model considers pressure drop, deactivation, pore diffusion, film heat transfer, and internal heat transfer when solving for the optimal conditions, and maps them as functions of design variables. This model can be up-scaled to provide guidance for optimal design of commercial-size reactors.

Optimized Photogrammetric Network Design With Flight Path Planner For Uav-Based Terrain Surveillance, Ivan Yair Rojas

Theses and Dissertations

This work demonstrates the use of genetic algorithms as a stochastic optimization technique for developing a camera network design and the flight path for photogrammetricapplications using Small Unmanned Aerial Vehicles. This study develops a Virtual Optimizer for Aerial Routes (VOAR) as a new photogrammetric mapping tool for acquisition of images to be used in 3D reconstruction. 3D point cloud models provide detailed information on infrastructure from places where human access may be difficult. This algorithm allows optimized flight paths to monitor infrastructure using GPS coordinates and optimized camera poses ensuring that the set of images captured is improved for 3D …

Gasification Of Biomass, Coal, And Petroleum Coke At High Heating Rates And Elevated Pressure, Aaron D. Lewis

Theses and Dissertations

Gasification is a process used to convert any carbonaceous species through heterogeneous reaction to obtain the desired gaseous products of H2 and CO which are used to make chemicals, liquid transportation fuels, and power. Both pyrolysis and heterogeneous gasification occur in commercial entrained-flow gasifiers at pressures from 4 to 65 atm with local gas temperatures as high as 2000 °C. Many gasification studies have been performed at moderate temperatures, heating rates, and pressures. In this work, both pyrolysis and char gasification experiments were performed on coal, petroleum coke, and biomass at conditions pertinent to commercial entrained-flow gasifiers. Rapid biomass pyrolysis …

Preparation Of Active, Stable Supported Iron Catalysts And Deactivation By Carbon Of Cobalt Catalysts For Fischer-Tropsch Synthesis, Kamyar Keyvanloo

Theses and Dissertations

The first half of this dissertation reports the development of supported Fe FT catalysts including the effects of various, carefully chosen preparation methods on the performance of alumina-supported iron/copper/potassium (FeCuK/Al2O3); it was determined that non-aqueous slurry impregnation and co-impregnation yielded catalysts with activities as high as any reported in the literature. Furthermore, the effects of support properties including pore size, hydroxyl group concentration, and support stabilizer were investigated for FeCuK/Al2O3 catalysts containing 20 or 40% Fe. For the first time, we report the performance of a supported Fe FT catalyst that is not only more active and stable than any …

Use Of Blood Oxygenator Membrane Units In Teaching Mass Balances, Friction Factor And Mass Transfer Analysis, Keith Mciver

Theses and Dissertations

Many applications of chemical engineering principles are biomedical but traditional chemical engineering education does not focus on these applications. New laboratory experiments with hollow fiber blood oxygenators allow integration of concepts into already full programs. This work describes three new educational experiments that have been developed to introduce students to concepts of mass balances, mass transfer and momentum transfer as applied to a hollow fiber blood oxygenator. In addition, a new mass transfer correlation is presented for the Medtronic Affinity NT blood oxygenator, which has not been reported previously in the literature. Mass transfer of oxygen through the hollow fiber …

Development Of Experiments Involving Pharmaceutical Manufacturing Principles, Alexander Struck Jannini

Theses and Dissertations

Laboratory experiments were developed to incorporate pharmaceutical engineering concepts into Freshman-level engineering courses. The goal is to increase the interest of pharmaceutical engineering in students and provide the necessary background for more advanced courses in the field. The experiments can be used on an individual basis, or to be grouped into themes for more focused learning objectives. The laboratory experiments are available at the pharmaceutical knowledge and training website www.PharmaHUB.org under the Teaching Resources tab.