Chemical Engineering Commons^™

A Finite Element Simulation Of Temperature And Material Flow In Fricton Stir Welding, Mark J. Lasley

Theses and Dissertations

The purpose of this research was to use the Transvalor S.A. product, Forge3, to develop a finite element simulation of the friction stir welding process that improves the predictability of temperature evolution and material flow within the plunge portion of the process. Previous modeling created more heating within the billet than experimental results, probably due to the simplification of the simulation with adiabatic boundary conditions. More realistic tooling temperatures were included in this model as these affect heat evolution which is a determining factor in microcrystalline growth. These results were validated by experimental efforts using a billet and tooling instrumented …

Evaluation Of Seal Integrity Of Flexible Food Polytrays By Destructive And Non-Destructive Techniques, William James Barlow Jr.

Masters Theses

The military has recently suffered a reduction in production capacity due to the rejection of their flexible food packaging. The rejection of these polytrays was due to sealing defects and the high standards set forth for the sealing quality. These standards set by the military were likely too conservative and until a test could be developed and optimized to quantitatively measure seal integrity, the standards will remain very high. The optimized test, whether destructive or non-destructive, must show that a particular defect, which might currently cause rejection, will not affect the quality of the items contained if passed as a …

Biomimetic Synthesis Within Polyelectrolyte Microcapsules: Characterization Of Enzyme Catalyzed Polyphenols And Polypeptides, Rohit C. Ghan

Doctoral Dissertations

An enzyme-catalyzed synthesis of novel polymers within layer-by-layer (LbL) constructed polyelectrolyte microcapsules has been developed. This approach is based on the selective permeability of polyelectrolyte-capsule walls to monomer molecules. Conversely biocatalysts and forming polymeric chains cannot exit the micro-capsule interior because of their characteristic high molecular weight. Horseradish Peroxidase (HRP) was encapsulated into four bilayer PSS (poly-styrenesulfonate)/PAH (poly-allylamine hydrochloride) capsules with an average diameter of 5 μm using pH-driven pore opening. The polymerization of 4-(2-Aminoethyl) phenol hydrochloride (tyramine) catalyzed by HRP produces easily detectable fluorescent polymeric products after the addition of hydrogen peroxide to the system. It is known that …

Layer-By-Layer Nanoassembly Combined With Microfabrication Techniques For Microelectronics And Microelectromechanical Systems, Jingshi Shi

Doctoral Dissertations

The objective of this work is to investigate the combination of layer-by-layer self-assembly with microfabrication technology and its applications in microelectronics and MEMS.

One can assemble, on a standard silicon wafer, needed multilayers containing different nanoparticles and polymers and then apply various micromanufacturing techniques to form microdevices with nanostructured elements.

Alternate layer-by-layer self-assembly of linear polyions and colloidal silica at elevated temperatures have been firstly studied by QCM and SEM. LbL self-assembly and photolithography were combined to fabricate an indium resistor. The RTA method was employed in the fabrication. Hot-embossing technique as a reasonably fast and moderately expensive technique was …

Fluidization Of Nanoparticles, Caroline Hijung Nam

Dissertations

During the past decade, nanoparticles (1-100 nm) and nanocomposites have become the focus of many studies due to the unique properties of nanostructured materials that make them attractive for various applications. Due to their atomic and molecular interactions, nanoparticles and nanocomposites have unique and often favorable catalytic, mechanical, optical, electronic and / or other properties. For instance, nanocrystalline copper is up to 5 times harder than conventional micron sized copper particles. Nanocomposites, such as a homogenous mixture of different nanoparticles, can also exhibit improved properties. Other examples include coating and reacting nanoparticles with a second nanostructured phase. These processes are …

Fluidization Of Agglomerates Of Nanoparticles Under Different Force Fields, Jose A. Quevedo

Theses

Nanoparticles are the focus of many research activities, and in the near future they will be handled in large amounts by industry. Fluidization is a very important unit operation which is applied in several industrial processes.

In the present work, fluidization experiments with agglomerates of nanoparticles were done under different force fields: (1) gravity force or conventional fluidization; (2) a magnetic force field, which uses magnetic particles under the influence of a magnetic field; and (3) a centrifugal force, generated by a rotating frame that simulates higher gravity conditions.

Among the significant results with agglomerates of nanoparticles, conventional fluidization was …

Prediction Of Organic Droplet Behavior On A Solid Surface As Influenced By Aqueous Surfactant Solutions, Samuel Albert Morton Iii

Doctoral Dissertations

This dissertation presents a model capable of predicting equilibrium oil droplet contact angles on a solid surface immersed in surfactant solution, a thorough discussion of the effects of surfactant concentration and salt addition on contact angles, and an experimental investigation into the impact of voltage application to the solid surface on oil droplet shape in an aqueous/organic/solid system. The work contained in this dissertation resulted in five journal articles and numerous presentations.

The model applies current theories of surfactant self-assembly, the quasi-chemical approximation for solid surface adsorption, and various aqueous/organic/solid system properties to determine organic droplet contact angles. The computational …

Development Of An Accurate Toxicity Assay Using Genetically Engineered Bioluminescent Bacteria, Stacey M. Allsteadt-Barnlund

Masters Theses

Methods of developing and improving toxicity assays using genetically engineered bioluminescent bacteria PM6 and Shk1 were investigated. The EC₅₀ values for three metals (zinc, copper, and lead) were determined using these two strains and were compared with the EC₅₀ values calculated from the Microtox® assay, published inhibition to activated sludge specific oxygen uptake rate (SOUR) data (Madonii et al., 1999), and published EC₅₀ values from Microtox® for the same compounds (Kaiser and Devillers, 1994). This was done to evaluate the effectiveness of using strains PM6 and Shk1 to predict toxic effects to activated sludge as indicated by …

Development Of A Reagentless Amperometric Ethanol Biosensor Based On Yeast Alcohol Dehydrogenase And Its Coenzyme, Nad+, Coimmobilized On A Carbon Nanotubes- Modified Electrode, Justin Matthew Holland

Masters Theses

A reagentless amperometric ethanol biosensor was fabricated by modifying a glassy carbon (GC) electrode with a thin film of multi-walled carbon nanotubes (MWNTs) and depositing yeast alcohol dehydrogenase (YADH) and its coenzyme, nicotinamide adenine dinucleotide (NAD⁺), on the surface of the modified electrode. The enzyme was immobilized on the modified electrode using two techniques: adsorption and covalent attachment. Biosensors based on graphite and carbon nanofibers (CNFs) were also fabricated in a similar manner except that the enzyme was only adsorbed to the electrode surface.

The performance of the biosensors was assessed using a number of analytical techniques. Cyclic …

Gloss Development Of Spray-Coated Systems, Aaron W. Clark

Electronic Theses and Dissertations

A spray-coated system involves any substrate on which a liquid coating is applied in a drop-wise fashion. Inkjet printing is the controlled application of drops to print a surface and is the focus of this work. The gloss of the printed substrate is an important attribute of print quality. Print gloss depends on a number of factors, such as ink and media properties. Non-uniform gloss in different regions of a printed image can cause a decrease in quality of a printed sample. However, a good understanding of the gloss development of spray-coated systems is not available in the literature. Several …

Molecular Dynamics Simulation Of Aqueous Electrolytes Behavior In Nanochannels, Lingchen Liao

Masters Theses

This thesis discusses the molecular dynamics simulation to determine the density distribution and diffusion coefficient of aqueous electrolytes (CaCl2, NaF, NaCl, NaBr, NaI, KCl, CsCl, RbCl) within silica nanochannels at 298K. An atomistic wall model, charged Lennard-Jones models for the ions, and the SPC/E model for water have been used. The effect of different channel radius and wall charges on divalent CaCl2 electrolytes solutions is discussed in comparison with the previously studied behavior of monovalent NaCl solutions. The comparison of (NaF, NaCl, NaBr, NaI) aqueous solutions in 1.0 nm nanochannel reveals the effects of different anion sizes. Likewise, the comparison …

Analysis And Simulation Of A Batchwise Scotch Whisky Production Process, Thomas Benton Rogers

Masters Theses

Scotch whiskey is produced in a two step distillation process that has remained relatively unchanged for decades, even centuries. The chemical composition of the whiskey is vital to its flavor and character. Much work has been done to analyze and study the final composition of different whiskies. However, to date little work has been published that studies the composition of the distillate with respect to distillation time. The goal of this work is to develop an experimental basis for study of the scotch whisky production process. Experimental data would allow us to gain a better understanding of the effects of …

Cloning And Expression Of Cytochrome P450Cam, Sirisha Chada

Masters Theses

Polyaromatic hydrocarbons (PAHs) are ubiquitously present in the environment and have deleterious affects on humans. Cytochrome P450 enzymes have been found to be useful in the biodegradation of the PAHs through an initial hydroxylation step. This makes them more water-soluble and accessible to the action of other oxidases. Cytochrome P450_cam is a model P450 enzyme that has been mutated for enabling PAH and alkane hydroxylation. P450s therefore have potential for use in commercial process for production of primary alcohols.

Rhodococcus organisms have a special mechanism for transporting the hydrophobic hydrocarbons into their cells. Cloning of the P450_cam gene …

Novel Internally-Staged Ultrafiltration For Protein Purification, Meredith Ann Feins

Dissertations

A new ultrafiltration technique based on a multimembrane stack has been developed to fractionate proteins closer in molecular weight than conventionally possible. The technique is illustrated here by obtaining a pure protein product from a binary protein mixture. By employing membranes in series using the same membrane without any gaskets or spacers in-between, ultrafiltration is carried out to separate two proteins relatively close in molecular weight. Flat membranes, of the same molecular weight cutoff (MWCO) 30,000 or 100,000, are stacked together in the desired number, and ultrafiltration takes place. The membrane rejection of a protein is amplified with each additional …

Mathematical Modeling Of Transient State Transdermal Drug Delivery, Alison Nickol Weltner

Theses

In this work, a two-pathway mathematical model for transdermal drug delivery with iontophoresis is presented. The partial differential equations are described and then solved. An alternative, two-pathway, three-layer model is also presented, and the implications of the coefficients within the equation are discussed. Using Franz cell iontophoretic delivery data from three drug substances (amitriptyline HCl, clomipramine HCl, and nortriptyline HCl), the two-pathway model is regressed to determine the diffusion coefficient and the concentration within the skin at the drug reservoir interface. ANOVA analysis indicates a correlation between iontophoretic current and concentration of drug within the stratum corneum.

Application Of Polymer Rheology In Melt Blowing Process And Online Rheological Sensor, Yizhong Wang

Doctoral Dissertations

Polymer rheology plays a significant role in many polymer-processing operations such as polymer extrusion, fiber spinning, and nonwovens processing. To develop real time, online process and quality control system in these operations, knowledge of polymer rheology and how the rheological properties can be determined is crucial.

In this work, rheological properties of two melt blowing grades polypropylene (PP) under different processing conditions were determined by various off line methods, which includes dynamic rheological properties, shear and elongational viscosities. The elongational viscosity was measured at different Hencky strain by using semi-hyperbolic dies developed in this research group. Good master curves were …

Integration Of Design Scales And Its Application To Multi-Component Adsorption Systems, Parag S. Adhangale

Doctoral Dissertations

Macroscopic simulations of chemical engineering unit processes provide a means of visualizing the relationship between different process variables through the use of constitutive equations such as the mass, energy and momentum balances. Molecular simulations on the other hand provide an insight into processes on the molecular scale. These simulations coupled with various concepts from statistical mechanics, are often used to study the properties of materials under a range of process conditions.

In a natural extension to these two fields, we use molecular simulations to obtain physico-chemical properties required for use in the macroscopic simulations of multi-component adsorption systems. The application …

Statistical Mechanical Models Of Adsorption And Diffusion Of Fluids In Crystalline Nanoporous Materials: Extensions To Percolation And Multicomponent Fluids, Austin M. Newman

Masters Theses

Kamat et al. has developed an analytical statistical mechanical theory that can be used to model pure component and binary liquid mixtures confined within crystalline nanoporous materials [1, 2]. The theory can be used to predict diffusivities, adsorption isotherms, and heats of adsorption as functions of temperature, pressure, and composition. The predictions obtained from this theory can then be used in macroscopic process level simulations to investigate the use of new adsorbents without conducting expensive experiments.

Kamat et al. has verified that the analytical adsorption theory can be used to model methane confined within zeolite Na-Y [3]. However, the diffusion …

Feasibility Of Using The Least Square Deconvolution Approach To Resolve Three-Person Str Dna Mixture Samples, Christopher David Lucas

Masters Theses

The feasibility of using the least-square solution method to resolve three-person mixtures of short tandem repeat deoxyribonucleic acid (STR DNA) was explored in this work. Such three-person mixtures can occur in gang rapes and other violent crimes and there is currently no suitable method for resolving these mixtures. The method evaluated in this work was named LSD-3. Simulations were conducted using the MATLAB software package to evaluate the sensitivity of correct resolution to signal perturbations as a function of the relative mass ratios of the mixture contributors. Three enhancements to the LSD-3 method were investigated; locus concatenation, reference profile incorporation, …

Separation Of Fluoride Residue Arising From Fluoride Volatility Recovery Of Uranium From Spent Nuclear Fuel, Jennifer L. Ladd-Lively

Masters Theses

The overall objective of this study was to support an alternative hybrid process to meet Advanced Fuel Cycle Initiative (AFCI) goals, using fluorination and aqueous processing techniques, for treatment of spent nuclear fuel (SNF). The specific goal was to develop a simple aqueous dissolution process to separate two high-heat fission products, cesium and strontium, from SNF fluoride residues. This separation study was based on solubility differences examined by modeling using the HSC Chemistry 5.0 and OLI Stream Analyzer 1.2 programs. HSC automatically utilizes an extensive thermochemical database, which contains enthalpy (H), entropy (S), and heat capacity (Cp) data for more …

Design And Simulation Of An Induction Skull Melting System, Taide Tan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Incorporating volatile actinides, mainly americium into a metallic fuel pin (MFP) has been a serious problem due to americium’s high vapor pressure. An Induction Skull Melting (ISM) system was identified by Argonne National Laboratory (ANL) as a potential furnace design to cast MFPs. Through the development of the ISM system, the nuclear waste feedstock can be melted and injected into the mold for fabricating MFPs in the advanced nuclear fuel cycles. The main phenomena in this system include: induction melting process, casting process and mass transfer process of americium. Issues related to ISM system design for casting MFPs are discussed …

Silicon Based Micro Components For Use In Chemical Agent Detection, Scott R. Forrest

Doctoral Dissertations

The objective of this work was to model, fabricate and test silicon based micro components for applications in chemical agent detection. Part I deals with research done on tunable micro Fabry-Perot interferometers. These devices are designed for use in identifying chemicals that absorb radiation in the infrared range of the spectrum. Part II deals with research done on novel Layer by Layer (LbL) assembled enzyme microreactors. These devices are designed for use in identifying chemicals that absorb radiation in the ultraviolet and visible range of the spectrum.

The emphasis of Part I is on the design and modeling of Fabry-Perot …

Fatigue Of Drill Pipes Used In Horizontal Directional Drilling, Feibai Ma

Doctoral Dissertations

Fatigue is the most common cause of mini-HDD drill rod failure. It can occur at stress levels far below the normal operating stress in most drill stem components. Fatigue failures occur because the drill rod, after it has been forced into a curved path, undergoes a cyclic bending stress oscillating from tension to compression in concert with the other stress components caused by torque, thrust, or pullback.

When a rod breaks underground, there is considerable extra cost caused by the delay in “fishing” out the broken rod as well as the cost of replacing the rod. On the other hand, …

A Rapidly-Converging Alternative To Source Iteration For Solving The Discrete Ordinates Radiation Transport Equations In Slab Geometry, Nicholas J. Wager

Theses and Dissertations

I present a numerical technique to solve the time independent Boltzmann Transport Equation for the transport of neutrons and photons. The technique efficiently solves the discrete ordinates equations with a new iteration scheme. I call this new scheme the angle space distribution iteration method because it combines a non-linear, high angular-resolution flux approximation within individual spatial cells with a coarse angular-resolution flux approximation that couples all cells in a spatial mesh. This shown to be an efficient alternative to source iteration. The new method is implemented using the step characteristic and exponential characteristic spatial quadrature schemes. The latter was introduced …

Studies On Improved Integrated Membrane-Based Chromatographic Process For Bioseparation, Yanke Xu

Dissertations

To improve protein separation and purification directly from a fermentation broth, a novel membrane filtration-cum-chromatography device configuration having a relatively impermeable coated zone near the hollow fiber module outlet has been developed. The integrated membrane filtration-cum-chromatography unit packed with chromatographic beads on the shell side of the hollow fiber unit enjoys the advantages of both membrane filtration and chromatography; it allows one to load the chromatographic media directly from the fermentation broth or lysate and separate the adsorbed proteins through the subsequent elution step in a cyclic process.

Interfacial polymerization was carried out to coat the bottom section of the …

Kinetics Of Ho2 Abstraction Of H Atoms From Hydrocarbons And Thermochemical Properties Of Urethane Monomers And Radicals, Rajul Shah

Theses

SECTION I: Kinetics of HO₂ Abstraction of H Atoms From Hydrocarbons

Structures, internal rotational barriers and ideal gas thermochemical properties, ΔH^°_f98 for representative series of transition states for abstraction of H atoms from primary, secondary and tertiary hydrocarbons by the HO₂ radical, TC-HOOH (1), TCC-HOOH (2), TC₂C-HOOH (3), TC₃C-HOOH (4), TC₂CC-HOOH (5), TC₂CC-HOOHC (6) and TC₃CCC-HOOH (7) are analyzed in this study. Molecular structures and vibrational frequencies are determined at the B3LYP/6-3111G(d,p) density functional level. The S°₂₉₈ and C_p(T) values (300≤T/K≤1500) from vibrational, …

Metal-Doped Rare Earth Oxide Catalysts For Condensations To Ketones, Arvind Karkal Bhat

LSU Master's Theses

Metal-doped supported rare earth oxide catalysts were examined to determine their suitability for the decarboxylative condensation of two carboxylic acids to produce ketones. The catalysts were characterized based on chemisorption tests, coke analysis using thermo-gravimetric analysis and X-ray absorption spectroscopy. Effect of catalyst particle size on rate of reaction was studied for various supported cerium oxide catalysts. Catalysts were tested for activity, selectivity, and stability using isothermal fixed bed reactors. Optimal operating conditions for the production of diisopropyl ketone and methyl nonyl ketone were determined. It was found that supported cerium oxide catalysts effectively catalyzed the condensation of isobutyric acid …

Chemical Production Complex Optimization, Pollution Reduction And Sustainable Development, Aimin Xu

LSU Doctoral Dissertations

The objective of this research is to propose, develop and demonstrate chemical production complex optimization to determine the optimal configuration of chemical plants in a superstructure of possible plants. The Chemical Complex Analysis System is a new methodology that has been developed to determine the best configuration of plants in a chemical production complex based on the AIChE Total Cost Assessment (TCA) for economic, energy, environmental and sustainable costs. All new, energy-efficient, and environmentally acceptable plants using greenhouse gases that can produce potentially commercial products designed with HYSYS were integrated into the chemical complex using the System. The optimum configuration …

Ceria-Zirconia Oxide High Temperature Desulfurization Sorbent, Kwang Bok Yi

LSU Doctoral Dissertations

High temperature desulfurization of highly reducing coal-derived gases using ceria and ceria-zirconia sorbents is the primary object of this dissertation research. If H2S concentration is reduced to less than 1 ppmv the product gas may be used with fuel cells and downstream catalytic process. CeO2 is reduced to a non-stoichiometric oxide, which is superior to CeO2 in removing H2S. Moreover, ZrO2 addition to CeO2 to form a solid solution, Ce1-xZrxO2, increases the reducibility of CeO2. This should also result in improved desulfurization performance. Pure CeO2 and sorbents, both commercially available and prepared at LSU, were tested. XRD analysis indicated that …

Closed Material Cycles And Organic Solvent Recovery, Tim De Jong

Theses

A survey was conducted of the pharmaceutical sector in Ireland to establish organic solvent usage, recovery and treatment practices. The eleven companies covered by the survey, which included several of the worlds largest multinational companies, consumed in the region of 122,000 tonnes of organic solvent in 2002. Approximately 53,000 tonnes was recovered on-site while 69,000 tonnes of virgin solvent was brought on-site to replace that which was lost through wastewater treatment, incineration, fugitive emissions and off-site treatment or reuse. The total quantity of virgin solvent consumed by the eleven companies accounted for 75.4 % of organic solvent imports to Ireland. …