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Articles 571 - 600 of 759

Full-Text Articles in Chemical Engineering

The Surface Characteristics And Reactivity Of Residual Carbon In Coal Gasification Slag, Xianglong Zhao, Cai Zeng, Yanyan Mao, Wenhua Li, Yun Peng, Tao Wang, Boris Eiteneer, Vladimir Zamansky, Thomas H. Fletcher Jan 2010

The Surface Characteristics And Reactivity Of Residual Carbon In Coal Gasification Slag, Xianglong Zhao, Cai Zeng, Yanyan Mao, Wenhua Li, Yun Peng, Tao Wang, Boris Eiteneer, Vladimir Zamansky, Thomas H. Fletcher

Faculty Publications

In a slagging entrained-flow coal gasifier, a large portion of the inorganic matter will form liquid slag that may have strong physical and chemical interactions with char. Understanding the char-slag interaction is important for improving the modeling and design of gasifiers. This paper reports the characteristics of residual carbon in both coarse and fine slag from a typical entrained-flow coal water slurry gasifier. The surface characteristics of slag and residual carbon in slag were evaluated by scanning electron microscopy and energy dispersive X-ray spectroscopy. The reactivity of the residual carbon in slag was compared through thermal gravimetric analysis. It was …


Experimental Measurements During Combustion Of Moist Individual Foliage Samples, Brent M. Pickett, Carl Isackson, Rebecca Wunder, Thomas H. Fletcher, Bret Buitler, David R. Weise Jan 2010

Experimental Measurements During Combustion Of Moist Individual Foliage Samples, Brent M. Pickett, Carl Isackson, Rebecca Wunder, Thomas H. Fletcher, Bret Buitler, David R. Weise

Faculty Publications

Individual samples of high moisture fuels from the western and southern United States and humidified aspen excelsior were burned over a flat-flame burner at 987◦ ±12 C and 10±0.5 mol% O2. Time-dependent mass and temperature profiles of these samples were obtained and analysed. It was observed that significant amounts of moisture remained in the individual samples after ignition occurred. Temperature histories showed a plateau at 200◦–300 C at the leaf perimeter rather than at 100 C, with a plateau of 140 C for the leaf interior. Implications are that classical combustion models should be altered to reflect the behaviour of …


A Sub-Grid, Mixture–Fraction-Based Thermodynamic Equilibrium Model For Gas Phase Combustion In Firetec: Development And Results, Michael M. Clark, Thomas H. Fletcher, Rodman R. Linn Jan 2010

A Sub-Grid, Mixture–Fraction-Based Thermodynamic Equilibrium Model For Gas Phase Combustion In Firetec: Development And Results, Michael M. Clark, Thomas H. Fletcher, Rodman R. Linn

Faculty Publications

The chemical processes of gas phase combustion in wildland fires are complex and occur at length-scales that are not resolved in computational fluid dynamics (CFD) models of landscape-scale wildland fire. A new approach for modelling fire chemistry in HIGRAD/FIRETEC (a landscape-scale CFD wildfire model) applies a mixture–fraction model relying on thermodynamic chemical equilibrium to predict combustion flame temperatures and product species compositions. The mixture–fraction approach is common in combustor modelling applications. However, since individual flame sheets are not resolved in HIGRAD/FIRETEC, application of the mixture–fraction approach requires the development of a sub-grid model, which is based on the two assumptions …


Investigation Of Nitrogen Release During Coal Pyrolysis In An Oxy-Fuel Combustion Process, John M. Sowa, Kolbein K. Kolste, Thomas H. Fletcher Jan 2010

Investigation Of Nitrogen Release During Coal Pyrolysis In An Oxy-Fuel Combustion Process, John M. Sowa, Kolbein K. Kolste, Thomas H. Fletcher

Faculty Publications

Three coals were studied in a flat flame burner (FFB) to determine nitrogen release during pyrolysis as a function of the temperature from 1600 to 1900 K in an oxy-fuel environment. The oxy-fuel environment was created by replacing the background N2 with CO2 in the FFB experiments. Both types of experiments were conducted under fuel-rich conditions, with no O2 present in the postflame gases. The oxy-fuel results were compared to previous results from FFB experiments in a N2 atmosphere. A bituminous coal showed no difference in mass and nitrogen release between the two environments. The sub-bituminous coal exhibited higher mass …


Improved Method For The Determination Of Kinetic Parameters From Non-Isothermal Thermogravimetric Analysis (Tga) Data, Thomas H. Fletcher, James L. Hillier, Trent Bezzant Jan 2010

Improved Method For The Determination Of Kinetic Parameters From Non-Isothermal Thermogravimetric Analysis (Tga) Data, Thomas H. Fletcher, James L. Hillier, Trent Bezzant

Faculty Publications

Thermogravimetric analysis (TGA) at a constant heating rate is a popular technique for characterizing reaction behavior. Determination of kinetic coefficients from suchTGAdata has given rise to a large range of reported activation energies for similar samples. In general, rate coefficients are determined using either a linearized integral method or a derivative method. A new method incorporating several well-known techniques is presented that avoids the problems with the linearized techniques as they are generally used. This paper compares results from the new method with results using either the integral or derivative method. Mathematically generated data were used with known kinetic parameters …


Thermal And Mechanical Multistate Folding Of Rnase H, Thomas A. Knotts, Terry J. Schmitt, Jonathan E. Clark Dec 2009

Thermal And Mechanical Multistate Folding Of Rnase H, Thomas A. Knotts, Terry J. Schmitt, Jonathan E. Clark

Faculty Publications

Two different classes of experimental techniques exist by which protein folding mechanisms are ascertained. The first class, of which circular dichroism is an example, probes thermally-induced folding. The second class, which includes atomic force microscopy and optical tweezers, measures mechanically-induced folding. In this article, we investigate if proteins fold/unfold via the same mechanisms both thermally and mechanically. We do so using Ribonuclease H, a protein that has been shown to fold through a three-state mechanism using both types of experimental techniques. A detailed, molecular-level description of the states involved in thermal and mechanical folding shows that mechanisms for both types …


Prediction Of Fluid Viscosity Through Transient Molecular Dynamic Simulations, Jason Christopher Thomas Dec 2009

Prediction Of Fluid Viscosity Through Transient Molecular Dynamic Simulations, Jason Christopher Thomas

Theses and Dissertations

A novel method of calculating viscosity from molecular dynamics simulations is developed, benchmarked, and tested. The technique is a transient method which has the potential to reduce CPU requirements for many conditions. An initial sinusoidal velocity profile is overlaid upon the peculiar velocities of the individual molecules in an equilibrated simulation. The transient relaxation of this initial velocity profile is then compared to the corresponding analytical solution of the momentum equation by adjusting the viscosity-related parameters in the constitutive equation that relate the shear rate to the stress tensor. The newly developed Transient Molecular Dynamics (TMD) method was tested for …


Energy Efficiency Of Hydrogen Sulfide Decomposition In A Pulsed Corona Discharge Reactor, Morris D. Argyle, Sanil John, Jerry C. Hamann, Suresh S. Muknahallipatna, Stanislaw Legowski, John F. Ackerman Dec 2009

Energy Efficiency Of Hydrogen Sulfide Decomposition In A Pulsed Corona Discharge Reactor, Morris D. Argyle, Sanil John, Jerry C. Hamann, Suresh S. Muknahallipatna, Stanislaw Legowski, John F. Ackerman

Faculty Publications

A novel pulsed corona wire-in-tube reactor with quartz view-ports allowed visual observation of the effect of charge voltage and gas composition on the corona distribution. The H2S conversion and energy efficiency of H2S decomposition in this pulsed corona discharge reactor varied at constant power due to the selected values of the electrical parameters of pulse forming capacitance, charge voltage, and pulse frequency. Low pulse forming capacitance, low charge voltage, and high pulse frequency operation produce the highest energy efficiency of H2S conversion at constant power. H2S conversion is more efficient in Ar-N2 gas mixtures than in Ar or N2. these …


Using Artificial Neural Networks And Model Predictive Control To Optimize Acoustically Assisted Doxorubicin Release From Polymeric Micelles, Ghaleb A. Husseini, Farouq S. Mjalli, William G. Pitt, Nabil M. Abdel-Jabbar Dec 2009

Using Artificial Neural Networks And Model Predictive Control To Optimize Acoustically Assisted Doxorubicin Release From Polymeric Micelles, Ghaleb A. Husseini, Farouq S. Mjalli, William G. Pitt, Nabil M. Abdel-Jabbar

Faculty Publications

We have been developing a drug delivery system that uses Pluronic P105 micelles to sequester a chemotherapeutic drug - namely, Doxorubicin (Dox) - until it reaches the cancer site. Ultrasound is then applied to release the drug directly to the tumor and in the process minimize the adverse side effects of chemotherapy on non-tumor tissues. Here, we present an artificial neural network (ANN) model that attempts to model the dynamic release of Dox from P105 micelles under different ultrasonic power intensities at two frequencies. The developed ANN model is then utilized to optimize the ultrasound application to achieve a target …


Studies Of Coal Nitrogen Release Chemistry For Oxyfuel Combustion And Chemical Additives, John M. Sowa Nov 2009

Studies Of Coal Nitrogen Release Chemistry For Oxyfuel Combustion And Chemical Additives, John M. Sowa

Theses and Dissertations

Pollution is one of the greatest concerns with pulverized coal combustion. With tightening standards on pollution emissions, more information is needed to create better design models. Burner modifications are the most efficient changes that can be made to assure sufficient carbon burnout and low NOx emissions. Experiments were performed in the BYU Flat Flame Burner (FFB) lab, operating under fuel rich conditions for pyrolysis experiments and fuel lean conditions for char oxidation experiments. Effects of temperature, coal rank, residence time, and post flame oxygen content on mass release, nitrogen release, and reactivity were examined. Elemental and Inductively coupled plasma (ICP) …


Improved Implementation Of Kirkwood-Buff Solution Theory In Periodic Molecular Simulations, Joseph W. Nichols, Stan G. Moore, Dean R. Wheeler Nov 2009

Improved Implementation Of Kirkwood-Buff Solution Theory In Periodic Molecular Simulations, Joseph W. Nichols, Stan G. Moore, Dean R. Wheeler

Faculty Publications

Kirkwood-Buff (KB) solution theory is a means to obtain certain thermodynamic derivatives from knowledge of molecular distributions. In actual practice the required integrals over radial distribution functions suffer inaccuracies due to finite-distance truncation effects and their use in closed systems. In this work we discuss how best to minimize these inaccuracies under traditional KB theory. In addition we implement a method for calculating KB quantities in molecular simulations with periodic boundary conditions and particularly within the canonical ensemble. The method is based on a finite-Fourier-series expansion of molecular concentration fluctuations and leads to more reliable results for a given computational …


Optimizing The Release And Methylation Of Bacterial Endospore Dipicolinic Acid, Aaron N. Nackos Nov 2009

Optimizing The Release And Methylation Of Bacterial Endospore Dipicolinic Acid, Aaron N. Nackos

Theses and Dissertations

Rapid, portable detection of biological threat agents such as Bacillus anthracis endospores (“spores”) is extremely important given the real and perceived threats of bioterrorism. Gas chromatography-mass spectrometry (GC-MS) is an excellent general means for chemical detection, although special sample preparation and specialized equipment are required to employ GC-MS for detecting biological agents such as spores in the field. A GC sample introduction probe consisting of a helical wire that can be retracted inside a syringe needle, called a coiled wire filament (CWF), was employed as a simple, passively-heated means to introduce the mixture of spores plus reagents for thermochemolysis methylation …


Deposition Of Particulate From Coal-Derived Syngas On Gas Turbine Blades Near Film Cooling Holes, Weiguo Ai Aug 2009

Deposition Of Particulate From Coal-Derived Syngas On Gas Turbine Blades Near Film Cooling Holes, Weiguo Ai

Theses and Dissertations

Synfuel from gasification of coal, biomass, and/or petroleum coke is an alternative to natural gas in land-based industrial gas turbines. However, carryover fine particulate in the syngas may lead to a considerable amount of deposition on turbine blades, which reduces component life and system performance. Deposition experiments on film-cooled turbine components were performed in an accelerated test facility to examine the nature of flyash deposits near film cooling holes. Experimental results indicate that deposition capture efficiency decreased with increased blowing ratio. Shaped holes exhibited more span-wise coverage than cylindrical holes and effectively reduced deposition. The TBC layer increased surface temperature, …


Investigation Of Additives For Use In Electroless Plating Solutions For Fabrication Of Nanowires, Elliott J. Bird Jun 2009

Investigation Of Additives For Use In Electroless Plating Solutions For Fabrication Of Nanowires, Elliott J. Bird

Theses and Dissertations

This study focused on improvement of electroless plating methods by use of particular bath additives. The techniques developed here can enable us to plate very thin layers selectively on a nonconductive substrate and thus create metallized features on a nanoscale. Through the development of such bottom-up techniques this work contributes a key technology to achieving self-assembled nanocircuits. The use of additives in an electroless plating environment can modify the barriers to nucleation (or seeding) and growth. Two additives, namely 3-mercapto-1-propanesulfonic Acid (MPS) and 1,3-propanedisulfonic acid (PDS), notably increased the selectivity of electroless metallization on chemically modified surfaces, which can be …


Understanding Performance--Limiting Mechanisms In Li-Ion Batteries For High-Rate Applications, Indrajeet Vilasrao Thorat Apr 2009

Understanding Performance--Limiting Mechanisms In Li-Ion Batteries For High-Rate Applications, Indrajeet Vilasrao Thorat

Theses and Dissertations

This work presents novel modeling and experimental techniques that provide insight into liquid-phase mass transport and electron transfer processes in lithium-ion batteries. These included liquid-phase ionic mass transport (conduction and diffusion), lithium diffuion in the solid phase and electronic transport in the solid phase. Fundamental understanding of these processes is necessary to efficiently design and optimize lithium-ion batteries for different applications. To understand the effect of electrode structure on the electronic resistance of the cathode, we tested power performance of cathodes with combinations of three different carbon conductivity additives: vapor-grown carbon fibers (CF), carbon black (CB) and graphite (GR). With …


Ultrasonic Drug Delivery To Tumors Via Stealth Liposomes, Peter Jones, Ghaleb A. Husseini, William G. Pitt, Beverly L. Roeder Apr 2009

Ultrasonic Drug Delivery To Tumors Via Stealth Liposomes, Peter Jones, Ghaleb A. Husseini, William G. Pitt, Beverly L. Roeder

Faculty Publications

Our research develops ultrasonically-controlled drug delivery systems. Previous micellar drug carriers released the drug upon ultrasonication. We have developed a liposomal drug carrier that is even more effective upon insonation in reducing tumors.


Laser Levitation Of Solid Particles For Combustion And Gasification Applications, Skigh E. Lewis Mar 2009

Laser Levitation Of Solid Particles For Combustion And Gasification Applications, Skigh E. Lewis

Theses and Dissertations

This dissertation details theoretical and experimental work in the development of a novel combustion diagnostic: laser levitation of solid particles. Theoretical analyses of the forces involved in the suspension of solid particles in a laser beam provide a comprehensive description of the levitation mechanism. Experimental work provides extensive observations and data that describe each of the forces involved, including results from detailed models. Theoretical models establish that a free-convective drag force, light scattering, photon momentum, and other minor forces contribute to the trapping mechanism. The theory quantitatively predicts particle temperature and magnitudes of each of the forces involved. Experimental measurements …


A New Model For Aqueous Electrolyte Solutions Near The Critical Point Of Water Incorporating Aqueous Reaction Equilibria, Craig J. Peterson Feb 2009

A New Model For Aqueous Electrolyte Solutions Near The Critical Point Of Water Incorporating Aqueous Reaction Equilibria, Craig J. Peterson

Theses and Dissertations

Aqueous electrolyte solutions at temperature and pressure conditions near the critical point of water are difficult to describe using traditional equations of state based upon the excess Gibbs energy. Models based upon the residual Helmholtz energy have proven more effective. Anderko and Pitzer1 developed a residual Helmholtz energy model (AP) for aqueous electrolyte solutions in which the electrolyte is assumed to be fully associated. The model has been effectively used in describing densities and vapor-liquid equilibria for simple electrolyte systems. The model is less effective for describing enthalpic properties such as heats of dilution. Oscarson and coworkers2, 3 modified the …


Redox, Pressure And Mass Transfer Effects On Syngas Fermentation, Allyson White Frankman Feb 2009

Redox, Pressure And Mass Transfer Effects On Syngas Fermentation, Allyson White Frankman

Theses and Dissertations

The fermentation of syngas (a mixture of CO, CO2 and H2) to produce ethanol is of interest as an alternative fuel. Clostridium carboxidivorans, has been found to produce higher than average amounts of ethanol and butanol from CO-rich mixtures. This project sought to determine the effects of the redox level in the solution, partial pressures in the headspace and mass transfer limitations on the products obtained through fermentation of syngas. It was determined that cysteine sulfide has a greater effect on the redox level of the media used to grow bacteria, than does the gas composition. Therefore, changing gas …


Prediction Of Light Gas Composition In Coal Devolatilization, Ravichandra S. Jupudi, Vladimir Zamansky, Thomas H. Fletcher Jan 2009

Prediction Of Light Gas Composition In Coal Devolatilization, Ravichandra S. Jupudi, Vladimir Zamansky, Thomas H. Fletcher

Faculty Publications

The chemical percolation devolatilization (CPD) model describes the devolatilization behavior of rapidly heated coal based on the chemical structure of the coal. It predicts the overall char, tar, and light gas yields. This paper presents an improved CPD model with improved capability for predicting light gas composition. This is achieved by incorporating a kinetic model that simulates the release of various light gas species from their respective sources/functional groups in coal. The improved CPD model is validated using experiments with a wire mesh reactor and published experimental observations


Flame Interactions And Burning Characteristics Of Two Live Leaf Samples, Brent M. Pickett, Carl Isackson, Rebecca Wunder, Thomas H. Fletcher, Bret W. Butler, David R. Weise Jan 2009

Flame Interactions And Burning Characteristics Of Two Live Leaf Samples, Brent M. Pickett, Carl Isackson, Rebecca Wunder, Thomas H. Fletcher, Bret W. Butler, David R. Weise

Faculty Publications

Combustion experiments were performed over a flat-flame burner that provided the heat source for multiple leaf samples. Interactions of the combustion behavior between two leaf samples were studied. Two leaves were placed in the path of the flat-flame burner, with the top leaf 2.5 cm above the bottom leaf. Local gas and particle temperatures, as well as local oxygen concentrations, were measured along with burning characteristics of both leaves. Results showed that the time to ignition of the upper leaf was not significantly affected by the presence of the lower leaf. The major difference observed was that the time of …


Multidimensional Modeling Of Solid Propellant Burning Rates And Aluminum Agglomeration And One-Dimensional Modeling Of Rdx/Gap And Ap/Htpb, Matthew Wilder Tanner Dec 2008

Multidimensional Modeling Of Solid Propellant Burning Rates And Aluminum Agglomeration And One-Dimensional Modeling Of Rdx/Gap And Ap/Htpb, Matthew Wilder Tanner

Theses and Dissertations

This document details original numerical studies performed by the author pertaining to solid propellant combustion. Detailed kinetic mechanisms have been utilized to model the combustion of the pseudo-propellants RDX/GAP and AP/HTPB. A particle packing model and a diffusion flame model have been utilized to develop a burning rate and an aluminum agglomeration model. The numerical model for RDX/GAP combustion utilizes a "universal" gas-phase kinetic mechanism previously applied to combustion models of several monopropellants and pseudo-propellants. The kinetic mechanism consists of 83 species and 530 reactions. Numerical results using this mechanism provide excellent agreement with RDX and GAP burning rate data, …


Mechanistic Investigation Of Ash Deposition In Pulverized-Coal And Biomass Combustion, Shrinivas Sadashiv Lokare Sep 2008

Mechanistic Investigation Of Ash Deposition In Pulverized-Coal And Biomass Combustion, Shrinivas Sadashiv Lokare

Theses and Dissertations

This investigation details the effects of fuel constituents on ash deposition through systematic experimental and theoretical analyses of fundamental particle experiments and a suite of fuels with widely varying inorganic contents and compositions. The experiments were carried out in the Multifuel Flow Reactor (MFR) at Brigham Young University. Fuels included several biomass fuels (straw, sawdust and mixtures of straw-sawdust with other additives such as Al(OH)3, CaCO3, etc.) and four commercially-used coals (Illinois#6, Powder River Basin – Caballo and Cordero, Blind Canyon, and Lignite – Beulah Zap). The data from the series of experiments quantitatively illustrate the effects of fuel properties, …


A-Priori Analysis Of Conditional Moment Closure Modeling Of A Temporal Ethylene Jet Flame With Soot Formation Using Direct Numerical Simulation, David O. Lignell, John C. Hewson, Jacqueline H. Chen Sep 2008

A-Priori Analysis Of Conditional Moment Closure Modeling Of A Temporal Ethylene Jet Flame With Soot Formation Using Direct Numerical Simulation, David O. Lignell, John C. Hewson, Jacqueline H. Chen

Faculty Publications

Modeling soot formation in turbulent nonpremixed combustion is a difficult problem. Unlike most gaseous combustion species, soot lacks a strong state relationship with the mixture fraction due to unsteady formation rates which overlap transport timescales, and strong differential diffusion between gaseous species and soot. The conditional moment closure model (CMC) has recently been applied to the problem of turbulent soot formation. A challenge in CMC modeling is the treatment of differential diffusion. Three-dimensional direct numerical simulation (DNS) of a nonpremixed ethylene jet flame with soot formation has been performed using a 19 species reduced ethylene mechanism and a four-step, three-moment, …


The Development Of A Computational Model Of Thrombosis In Hemodialysis Catheters, Daniel J. Lattin Jul 2008

The Development Of A Computational Model Of Thrombosis In Hemodialysis Catheters, Daniel J. Lattin

Theses and Dissertations

Thromboembolism (TE) significantly limits the usefulness and safety of blood-contacting devices such as hemodialysis catheters. Computer simulation of TE can provide understanding of the process and can facilitate the design of more effective devices. Previous work conducted at BYU successfully modeled TE in a simple, two-dimensional flow cell design by adding quantitative TE code to a commercial computational fluid dynamics (CFD) package, Fluent. This two-dimensional model predicted thrombus initiation and growth and adjusted flow to accommodate thrombus geometries, but was limited by computational power and unsophisticated meshing techniques. To build upon this work, and take advantage of BYU's new supercomputing …


Three-Dimensional Direct Numerical Simulation Of Soot Formation And Transport In A Temporally Evolving Nonpremixed Ethylene Jet Flame, David O. Lignell, Jacqueline H. Chen, Philip J. Smith Jul 2008

Three-Dimensional Direct Numerical Simulation Of Soot Formation And Transport In A Temporally Evolving Nonpremixed Ethylene Jet Flame, David O. Lignell, Jacqueline H. Chen, Philip J. Smith

Faculty Publications

Three-dimensional direct numerical simulation of soot formation with complex chemistry is presented. The simulation consists of a temporally evolving, planar, nonpremixed ethylene jet flame with a validated, 19-species reduced mechanism. A four-step, three-moment, semiempirical soot model is employed. Previous two-dimensional decaying turbulence simulations have shown the importance of multidimensional flame dynamical effects on soot concentration [D.O. Lignell, J.H. Chen, P.J. Smith, T. Lu, C.K. Law, Combust. Flame 151 (1–2) (2007) 2–28]. It was shown that flame curvature strongly impacts the diffusive motion of the flame relative to soot (which is essentially convected with the flow), resulting in soot being differentially …


Effects Of Moisture On Combustion Of Live Wildland Forest Fuels, Brent M. Pickett Jul 2008

Effects Of Moisture On Combustion Of Live Wildland Forest Fuels, Brent M. Pickett

Theses and Dissertations

Current operational wildland fire models are based on numerous correlations from experiments performed on dry (dead) fuel beds. However, experience has shown distinct differences in burning behaviors between dry and moist (live) fuels. To better understand these fundamental differences, an experiment was designed to use a flat-flame burner to simulate a moving fire front which heated and ignited a stationary, individual fuel sample. Samples included various U.S. species from the California chaparral, the intermountain west, and the southeastern regions. Temperature, mass, and video images were recorded throughout each experimental run from which numerous data values were obtained such as time …


Microkinetic Model Of Fischer-Tropsch Synthesis On Iron Catalysts, Uchenna Prince Paul Jul 2008

Microkinetic Model Of Fischer-Tropsch Synthesis On Iron Catalysts, Uchenna Prince Paul

Theses and Dissertations

Fischer-Tropsch synthesis (FTS), developed in the early 1900's, is defined as the catalytic conversion of H2 and CO to hydrocarbons and oxygenates with the production of H2O and CO2. Accurate microkinetic modeling can in principle provide insights into catalyst design and the role of promoters. This work focused on gaining an understanding of the chemistry of the kinetically relevant steps in FTS on Fe catalyst and developing a microkinetic model that describes FTS reaction kinetics. Stable Al2O3-supported/promoted (20% Fe, 1% K, 1% Pt) and unsupported Fe (99% Fe, 1% Al2O3) catalysts were prepared and characterized. Transient experiments including temperature programmed …


Vapor-Liquid Equilibrium Of Polymer Solutions During Thermal Decomposition Of Rigid Foams, Nathan H. King Jul 2008

Vapor-Liquid Equilibrium Of Polymer Solutions During Thermal Decomposition Of Rigid Foams, Nathan H. King

Theses and Dissertations

Removable Epoxy Foam (REF) and other rigid foams experience severe changes in structure and properties when exposed to high heat. As thermal energy breaks network bonds in the foam many species are formed, including large polymer-like network fragments and smaller solvent-like molecules. During this process a liquid phase may form. The vapor-liquid equilibrium (VLE) behavior of the polymer solutions formed during initial decomposition can be highly non-ideal. In this research VLE behavior of high-temperature polymer solutions was studied and a procedure was developed for predicting that behavior during decomposition of rigid foams. A high-temperature VLE facility was built and validated, …


Modeling Phase Transitions Of Nanoemulsion For Ultrasonic Gene Delivery, Ghaleb A. Husseini, William G. Pitt, Ram Singh Jul 2008

Modeling Phase Transitions Of Nanoemulsion For Ultrasonic Gene Delivery, Ghaleb A. Husseini, William G. Pitt, Ram Singh

Faculty Publications

A computer model was written that simulates the transformation of a nanoemulsion droplet to a gas bubble by the application of ultrasound. Experimentally such a technique could be used to enhance non-viral gene transfection beyond the boundary of the endothelial lining of the circulatory system, particularly in tumors exhibiting enhanced permeation and retention of nanoparticles.