Chemical Engineering Commons^™

Nonequilibrium Thermodynamics Modeling Of Coupled Biochemical Cycles In Living Cells, Yaşar Demirel

Yaşar Demirel Publications

Living cells represent open, nonequilibrium, self organizing, and dissipative systems maintained with the continuous supply of outside and inside material, energy, and information flows. The energy in the form of adenosine triphosphate is utilized in biochemical cycles, transport processes, protein synthesis, reproduction, and performing other biological work. The processes in molecular and cellular biological systems are stochastic in nature with varying spatial and time scales, and bounded with conservation laws, kinetic laws, and thermodynamic constraints, which should be taken into account by any approach for modeling biological systems. In component biology, this review focuses on the modeling of enzyme kinetics …

Supercritical Carbon Dioxide Processing Of Nano - Clays And Polymer/Clay Nanocomposites, Mihai Manitiu

Wayne State University Dissertations

Effective dispersion of the fillers in a polymer matrix and improvement of polymer-clay interactions are two key challenges in the field of nanocomposites. A novel processing method that utilizes the unique properties of supercritical carbon dioxide (scCO2) to disperse nano-clay and prepare a series of polymer/clay nanocomposites with enhanced properties was explored.

Significant dispersion was achieved using the scCO2 process with Cloisite 10A without the presence of an organic phase as evident by the absence of the diffraction peak in WAXD and the presence of individual tactoids that lost their parallel registry. The expanded flexible structure of the scCO2 processed …

Rotational Relaxation Times Of Individual Compounds With Simulations Of Molecular Asphalt Models, Liqun Zhang, Michael L. Greenfield

Chemical, Biomolecular, and Materials Engineering Faculty Publications

The dynamical properties of a complex system incorporate contributions from the diverse components from which it is constituted. To study this relationship in a multicomponent system, relaxation times based on rotation autocorrelation functions in molecular dynamics simulations were analyzed for molecules in two sets of unmodified and polymer-modified model asphalt/bitumen systems over 298–473 K. The model asphalt systems were proposed previously to approximate the chemical and mechanical properties of real asphalts. Relaxations were modeled using a modified Kaulrausch–Williams–Watts function and were based on the third Legendre polynomial of normal vector time correlation functions for aromatic species asphaltene, polar aromatic, naphthene …

Partitioning Of Perfluorooctanoate Into Phosphatidylcholine Bilayers Is Chain Length-Independent, Wei Xie, Geoffrey D. Bothun, Hans-Joachim Lehmler

Chemical, Biomolecular, and Materials Engineering Faculty Publications

The chain length dependence of the interaction of PFOA, a persistent environmental contaminant, with dimyristoyl- (DMPC), dipalmitoyl- (DPPC) and distearoylphosphatidylcholine (DSPC) was investigated using steady-state fluorescence anisotropy spectroscopy, differential scanning calorimetry (DSC) and dynamic light scattering (DLS). PFOA caused a linear depression of the main phase transition temperature T_m while increasing the width of the phase transition of all three phosphatidylcholines. Although PFOA's effect on T_m and the transition width decreased in the order DMPC > DPPC > DSPC, its relative effect on the phase behavior was largely independent of the phosphatidylcholine. PFOA caused swelling of DMPC but not DPPC …

A Multiscale Gibbs-Helmholtz Constrained Cubic Equation Of State, Angelo Lucia

Chemical, Biomolecular, and Materials Engineering Faculty Publications

This paper presents a radically new approach to cubic equations of state (EOS) in which the Gibbs-Helmholtz equation is used to constrain the attraction or energy parameter, a. The resulting expressions for a(T, p) for pure components and a(T, p, x) for mixtures contain internal energy departure functions and completely avoid the need to use empirical expressions like the Soave alpha function. Our approach also provides a novel and thermodynamically rigorous mixing rule for a(T, p, x).When the internal energy departure function is computed using Monte …

The Development And Application Of A Novel Free-Damage Fracturing Fluid (Ph<2), Jin Zhang, Yan Zhang, Yongfu Wu, Xiuqing He, Xinzhu Zhang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

At present, water-Based fracturing fluid systems are mainly polymer (macromolecule) and visco-elastic surfactant (micro molecule). Because of polymer properties and incomplete gelout, the damage to matrices and conductivity of artificial fractures will be inevitable. the surfactant-Based fracturing fluid system is a micro-molecule system not to damage artificial fractures. However, it is difficult to eliminate the damages from rock debris moving and clay swelling information. a novel free-damage fracturing fluid system (FDFF), a cationic surfactant derived from a long chain fatty acid, has been developed and applied in Daqing oil field. FDFF can crosslink in a wide range from a strong …

Retrofit Of Distillation Columns In Biodiesel Production Plants, Nghi Nguyen, Yaşar Demirel

Yaşar Demirel Publications

Column grand composite curves and the exergy loss profiles produced by the Column-Targeting Tool of the Aspen Plus simulator are used to assess the performance of the existing distillation columns, and reduce the costs of operation by appropriate retrofits in a biodiesel production plant. Effectiveness of the retrofits is assessed by means of thermodynamics and economic improvements. We have considered a biodiesel plant utilizing three distillation columns to purify biodiesel (fatty acid methyl ester) and byproduct glycerol as well as reduce the waste. The assessments of the base case simulation have indicated the need for modifications for the distillation columns. …

Alkyl Polyglycoside/1-Naphthol Formulations With Ultra-Low Interfacial Tensions Against N-Octane For Enhanced Oil Recovery, Stefan Iglauer, Yongfu Wu, Patrick Shuler, Yongchun Tang, William Goddard

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

We present Alkyl polyglycoside (APG)/1-naphthol formulations which show ultra-low interfacial tensions (IFT) against n-octane. We demonstrate that 1-naphthol is very efficient as a cosolvent in terms of reducing IFT. These formulations are therefore potentially suitable as agents for enhanced oil recovery (EOR). an increasing APG concentration strongly increased viscosity, and the formulations showed shear-thinning behavior. in a core flood EOR test we showed that this type of formulation significantly increased oil production. © 2010, European Association of Geoscientists and Engineers.

Designing A Whey Protein Based Material As A Scaffold For Bone Regeneration, Mia Dvora

LSU Doctoral Dissertations

A novel gel material was designed and optimized for use as a bone tissue regeneration scaffold. Whey protein isolate (WPI), the primary component of the material, underwent considerable testing for conformity to a set of known material characteristics required for application in bone regeneration. WPI gels of different compositions were fabricated by thermally inducing gelation of high-concentration protein suspensions, and characterized for compressive strength and modulus, hydration swelling and drying properties, mechanical behavior change due to polysaccharide additives, and intrinsic pore network structure. The gels were also tested for their compatibility with MC3T3-E1 cells, and interactions such as cell adhesion, …

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

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 …

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

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

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 …

Design And Development Of Highly Active, Nanoengineered, Platinum Based Core-Shell Electrodes For Proton Exchange Membrane Fuel Cells, Seth Louis Knupp

Legacy Theses & Dissertations (2009 - 2024)

Highly active nanoengineered core-shell electrocatalyst have a great potential to be used as fuel cell electrodes. They can alleviate problems related with commercial carbon supported platinum by simultaneously lowering cost while enhancing reaction kinetics and overall performance. More recently, use of nanoengineered core-shell electrode structures have showed their ability to enhance the stability and overall lifetime of the catalyst without sacrificing the electrode's performance. We studied the potential of using highly active core-shell nanoparticles supported on carbon nanomaterials as fuel cell electrodes.

Electroless Deposition Of Superconducting Magnesium Diboride Thin Films On Various Substrates, Khrupa Saagar Vijayaragavan

Wayne State University Theses

ABSTRACT

ELECTROLESS DEPOSITION OF SUPERCONDUCTING MAGNESIUM DIBORIDE THIN FILMS ON VARIOUS SUBSTRATES

by

KHRUPA SAAGAR VIJAYARAGAVAN

MAY 2010

Advisor: Dr. Susil K Putatunda

Dr. Gavin Lawes

Major: Chemical Engineering

Degree: Masters of Science

Superconducting thin films of magnesium diboride were synthesized by a novel electroless plating process. Electroless plating shares many similarities to electroplating with the major difference being the absence of a continuous bias voltage. Significantly, this work represents the first investigation where electroless deposition has been used to prepare compounds, as opposed to the elemental metals considered in all previous studies. Magnesium Diboride is a recently discovered superconducting …

Molecular Modeling Of Energetic Materials And Chemical Warfare Agents, Nandhini Sokkalingam

Wayne State University Dissertations

Contamination of military sites by energetic materials and chemical warfare agents is a growing problem. To avoid health hazards associated with these compounds, it is necessary to decontaminate or remediate the contaminated sites. Effective decontamination requires knowledge of environmental fate of contaminants and the appropriate remediation methodologies. While the fate of chemical warfare agents are well studied, the impact of certain energetic materials in the environment is relatively unknown. So the current focus is determining environmental fate of Insensitive Munitions (IM) which are energetic materials that have low shock sensitivity and high thermal stability and developing detection schemes for identifying …

Characterization Of Rock/Fluids Interactions At Reservoir Conditions, Dayanand Saini

LSU Doctoral Dissertations

In this study, interfacial phenomena of spreading, wettability, and rock/oil adhesion interactions in complex rock/oil/water systems were characterized at reservoir conditions of elevated pressures and temperatures. Capabilities of both ambient and reservoir condition optical cells were used for measuring the oil/water interfacial tension and dynamic (the water-receding and the water-advancing) contact angles for various complex rock/oil/water systems. Well known sessile oil drop volume alteration method was successfully used in this study for evaluating the applicability of the modified Young’s equation for characterizing the line tension in complex rock/oil/water systems at reservoir conditions. This appears to be first time when rock/fluids …

Electrostatic Quadrupole Plasma Mass Spectrometer Measurements During Thin Film Depositions Using Simultaneous Matrix Assisted Pulsed Laser Evaporation And Magnetron Sputtering, Chad N. Hunter, Michael H. Check, Christopher Muratore, Andrey A. Voevodin

Chemical and Materials Engineering Faculty Publications

A hybrid plasma deposition process, combining matrix assisted pulsed laser evaporation (MAPLE) of carbon nanopearls (CNPs) with magnetron sputtering of gold was investigated for growth of composite films, where 100 nm sized CNPs were encapsulated into a gold matrix. Composition and morphology of such composite films was characterized with x-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy (TEM) analysis. Carbondeposits on a gold magnetron sputter target and carbon impurities in the gold matrices of depositedfilms were observed while codepositing from gold and frozen toluene-CNP MAPLE targets in pure argon. Electrostatic quadrupole plasma analysis was used to determine that …

Development Of Wide Band Gap Semiconductor Materials For Renewable Energy, S.M. Sarif Masud

Open Access Theses & Dissertations

Several new wide band gap semiconductor nanocomposite photocatalytic materials have been synthesized from HTiNbO5 and HNb3O8 for solar energy conversion. As a source of renewable energy, the materials are being tested to produce hydrogen fuel from water via photolysis. The materials have high surface areas, are macroporous, and have flatband potentials suitable for reducing water to create hydrogen. Under visible or ultra violet light, the materials were found to be very promising as hydrogen evolving photocatalysts. As part of the synthesis of the composites, the catalysts also exhibited excellent catalytic activity under UV light for reducing ionic platinum and gold …