Chemical Engineering Commons^™

High Yield And Conversion Of Biodiesel From A Nonedible Feedstock (Pongamia Pinnata), Yogesh C. Sharma, Bhaskar Singh, John Korstad

College of Science and Engineering Faculty Research and Scholarship

An efficient approach has been adopted for the synthesis of biodiesel developed from karanja, a nonedible oil feedstock. A two-step reaction was followed for synthesis of biodiesel. Karanja oil possessing a high free fatty acid content was esterified with sulfuric acid, and the product obtained was further converted to fatty acid alkyl esters (biodiesel) by transesterification reactions. A moderate molar ratio of 6:1 (methanol/oil) was efficient for acid esterification with 1.5% v/v H₂SO₄ and 1 h of reaction time at 60 ± 0.5 °C, which resulted in reduction of FFA from 19.88 to 1.86 mg of KOH/g. …

Effects Of Preparative Parameters On The Structure And Performance Of Ca-La Metal Oxide Catalysts For Oil Transesterification, Shuli Yan, Manhoe Kim, Siddharth Mohan, Steven O. Salley, K.Y. Simon Ng

National Biofuels Energy Laboratory

The effects of preparative parameters on the surface basicity, composition, and transesterification activities of several Ca-La metal oxide catalysts were investigated. Four different preparation methods: ammonia-ethanol-carbon dioxide precipitation, physical mixing, impregnation, and co-precipitation, were studied. It was found that the ammonia-ethanol-carbon dioxide precipitation method resulted in the highest BET specific surface area, base strength and base site concentration. Moreover, catalyst surface composition and basicity are a function of calcination temperature, precipitants, pH, and molar ratio of Ca to La in precursor solution, and storage conditions. XRD, XPS, basicity and BET tests revealed that catalyst structure and dispersion of Ca species …

Oscillatory And Monotonic Modes Of Long-Wave Marangoni Convection In A Thin Film, Sergey Shklyaev, Mikhail Khenner, Alexei Alabuzhev

Mathematics Faculty Publications

We study long-wave Marangoni convection in a layer heated from below. Using the scaling k=O Bi, where k is the wave number and Bi is the Biot number, we derive a set of amplitude equations. Analysis of this set shows presence of monotonic and oscillatory modes of instability. Oscillatory mode has not been previously found for such direction of heating. Studies of weakly nonlinear dynamics demonstrate that stable steady and oscillatory patterns can be found near the stability threshold.

Non-Planar Diamond Electrodes For Biomedical Neural Sensing And Stimulating, Jeffrey M. Halpern

Chemical Engineering

Abstract

Conductive diamond has exceptional chemical stability, making it an appealing candidate material for long-term medical device implants. This work describes the characterization, and fabrication of four diamond-based neural devices. A previously developed 30 µm diamond-disk in vitro needle electrode was characterized. The device could detect 1 nM concentration analytes in a flow cell using fast scan cyclic voltammetry, but the fabrication was not reproducible. A novel in vitro diamond device was developed with diamond selectively grown at the tip of a hollow quartz capillary, resulting in a 2-4 µm tip diameter. The diamond tip shape and size were geometrically …

Oscillatory And Monotonic Modes Of Long-Wave Marangoni Convection In A Thin Film, Sergey Shklyaev, Mikhail Khenner, Alexei Alabuzhev

Mathematics Faculty Publications

We study long-wave Marangoni convection in a layer heated from below. Using the scaling k=O Bi, where k is the wave number and Bi is the Biot number, we derive a set of amplitude equations. Analysis of this set shows presence of monotonic and oscillatory modes of instability. Oscillatory mode has not been previously found for such direction of heating. Studies of weakly nonlinear dynamics demonstrate that stable steady and oscillatory patterns can be found near the stability threshold.

Applications Of Ultrafine Powder Coatings, A.S. Mohammad Sayem Mozumder

Digitized Theses

Powder coatings have emerged as an alternative to the conventional liquid coatings when environmental regulations become stricter every year. The advantage of powder coatings mainly renders to their solvent-free formulations, because solvent(s) used in liquid coatings are to be evaporated to environment contributing to the total volatile organic compounds (VOCs) emissions. Although advantageous, until recently, powder coating was not able to provide surface finishes comparable to the liquid coatings. However, when ultrafine powders (particularly, in the size range of 15-25 µm) becomes flowable with the aid of nano-additive(s), ultrafine powder coatings (UPCs) came into business with its thinner and smoother …

Design Of A Polysaccharide Derived Tissue Engineered Vascular Graft, Irina Robu

Wayne State University Dissertations

DESIGN OF A POLYSACCHARIDE DERIVED TISSUE ENGINEERED VASCULAR GRAFT

By

Irina Robu

November 2010

Advisor: Dr. Howard Matthew

Major: Chemical Engineering

Degree: Doctor of Philosophy

As the most frequent congenital anomaly and the leading cause of death, congenital heart disease is an attractive target for tissue engineering research. The challenging target to engineer a native blood vessel stems from the need to find substitutes for pediatric patients born with congenital defects. The tissue engineering graft functions to bring various cells of the vasculature in close proximity to one another to enable intercellular signaling which facilitates cell adhesion, migration and differentiation. …

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 …

Identifying Multiple Steady States In The Design Of Reactive Distillation Processes, Thomas Karl Mills

Doctoral Dissertations

"Global homotopy continuation is used to identify multiple steady states in ideal reactive flash and reactive distillation systems involving a reaction of the form A+B [symbol for <--> C taking place in the liquid phase. The choice of specifications has an influence on the existence of multiple solutions for both the flash and the column. For the flash, specification of the heat input or withdrawal can give rise to multiplicities while specification of the split fraction does not. Specification of one internal energy balance variable and one external material balance variable does not produce multiplicities in the column; however, specification of …

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. …

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 …

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 …

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 …

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 …