Chemical Engineering Commons^™

The Influence Of Electrolytic Conditions On Synthesis Of Feo42-, Yan Zhou, Wei-Hua Yang, Dong-Qin Bi, Ting-Ting Huang, Zhen Sun, Quan-Feng Guo

Journal of Electrochemistry

The FeO₄^2-was synthesized using iron lattice as anode and the solid K₂FeO₄ was also prepared.Influence of electrolytic conditions,such as stir,ultrasonic,temperature and current density on the current efficiency were studied.The results showed that preferable ferrate(VI) current yield was obtained in a current density of 10 mA·cm^-2,temperature 30 ℃ and 14 mol/L NaOH as electrolyte under at stirring effect.

Electrochemical Oxidation Of The Phenol In The Chloride System, Yong Liu, Dan Liu, Shi-Lin Zhao, Jing-Jing Lai

Journal of Electrochemistry

The Ru-Ir /Ti electrode as cathode to electrolysis the synthetic phenolic wastewater was studied. The effect of the initial chloride concentration on the electrolytic treatment result has been discussed. Experiment result shows that the electrochemical oxidation of phenol suits to one kinetics equation in given electrolytic time. If the initial chloride concentration in wastewater increases, the time of the electrochemical oxidation of phenol can be shorten, in other words the apparent rate constant is greater. The middle matters of electrochemical oxidation of phenol in the chloride system detected out by HPLC and GC-MS is mainly 1-chloro-phenol, 4-chloro-phenol, 2,4-dichloro-phenol, 2,6-dichloro-phenol, 2,4,6-trichloro-phenol, …

Mwnts Modified Gc Electrode For Hydrogen Peroxide Determination, Hong-Juan Wang, Chun-Mei Zhou, Hao Yu, Feng Peng, Jin-Kun Fang

Journal of Electrochemistry

A MWNTs modified GC electrode was constructed successfully to be used to detect hydrogen peroxide.Two methods of maximum anodic current of cyclic voltommogram and chronoamperometry were adopted to measure the concentration of hydrogen peroxide.The results show that the MWCNTs can enlarge the effective surface area of GC electrode and can enormously enhance the electron transfer.The sensitivity and correlation coefficient for hydrogen peroxide detection are 2.84 μA/mmol·L^-1,0.997 and 1.5 μA/mmol·L^-1,0.971 for cyclic voltammetry and chronoamperometry,respectively.The procedure of the two methods to detect hydrogen peroxide is simple,and the results obtained are satisfied.

A Coarse Grain Model For Dna, Thomas A. Knotts, Nitin Rathore, David C. Schwartz, Juan J. De Pablo

Faculty Publications

Understanding the behavior of DNA at the molecular level is of considerable fundamental and engineering importance. While adequate representations of DNA exist at the atomic and continuum level, there is a relative lack of models capable of describing the behavior of DNA at mesoscopic length scales. We present a mesoscale model of DNA that reduces the complexity of a nucleotide to three interactions sites, one each for the phosphate, sugar, and base, thereby rendering the investigation of DNA up to a few microns in length computationally tractable. The charges on these sites are considered explicitly. The model is parametrized using …

Identification And Characterization Of Calcium And Manganese Transporting Atpase (Pmr1) Gene Of Pichia Pastoris, Michael P. Dux, Mehmet Inan

Papers in Biotechnology

A gene homologous to Saccharomyces cerevisiae PMR1 has been cloned in the methylotrophic yeast Pichia pastoris.The entire P. pastoris PMR1 gene (PpPMR1 ) codes a protein of 924 amino acids. Sequence analysis of the PpPMR1 cDNA and the genomic DNA revealed that there is no intron in the coding region. The putative gene product contains all of the conserved regions observed in P-type ATPases and exhibits 66.2%, 60.3% and 50.6% identity to Pichia angusta (Hansenula polymorpha), Saccharomyces cerevisiae PMR1 and human ATP2C1 gene products, respectively. A pmr1 null mutant strain of P. pastoris exhibited growth defects in media with the …

Optical Emission Study Of Nonthermal Plasma Confirms Reaction Mechanisms Involving Neutral Rather Than Charged Species, Gui-Bing Zhao, Morris D. Argyle, Maciej Radosz

Faculty Publications

Charge transfer reactions are commonly used to explain NO_x conversion in nonthermal plasma. An analysis of optical emission spectra induced by pulsed corona discharge in NO_x-containing argon suggests that, in fact, the contribution of charge transfer reactions to NO_x conversion in nonthermal plasma is negligible. During electrical discharge in such gas mixtures, NO (B)⁠, an electronic excited state of NO formed due to the dissociative recombination reactions of NO_x⁺ and N₂O⁺ and the optical emission of NO (B) could be a proof that cations are responsible for NO_x conversion. However, …

Modeling And Sensitivity Analysis Of Acoustic Release Of Doxorubicin From Unstabilized Pluronic P105 Using An Artificial Neural Network Model, Ghaleb A. Husseini, Nabil M. Abdel-Jabbar, Farouq S. Mjalli, William G. Pitt

Faculty Publications

This paper models steady state acoustic release of Doxorubicin (Dox) from Pluronic P105micelles using Artificial Neural Networks (ANN). Previously collected release data werecompiled and used to train, validate, and test an ANN model. Sensitivity analysis was thenperformed on the following operating conditions: ultrasonic frequency, power density, Plu-ronic P105 concentration, and temperature. The model showed that drug release was mostefficient at lower frequencies. The analysis also demonstrated that release increases as thepower density increases. Sensitivity plots of ultrasound intensity revealed a drug releasethreshold of 0.015 W/cm2 and 0.38 W/cm2 at 20 and 70 kHz, respectively. The presence ofa power density threshold …

Hydrodynamics Investigation Of In-Vitro Dissolution Testing, Ge Bai

Dissertations

Dissolution testing is routinely carried out in the pharmaceutical industry to determine dissolution rate of solid dosage forms. The United States Pharmacopoeia (USP) Dissolution Apparatus II is the device most commonly used for this purpose. Despite its widespread use, dissolution testing remains susceptible to significant error and test failures. Limited information is available on the hydrodynamics of this apparatus, although hydrodynamic effects can play a major role on test performance.

Laser-Doppler Velocimetry (LDV) and Computational Fluid Dynamics (CFD) were used here to experimentally map and computationally predict the velocity distribution inside a standard USP Apparatus II under the typical operating …

Solvent Resistant Microporous/Nanoporous Polymeric Hollow Fiber And Flat Film Membranes And Their Applications, Praveen B. Kosaraju

Dissertations

The separation and purification of organic-solvent-based process streams may be carried out by membrane processes such as nanofiltration/ultrafiltration/microfiltration and membrane solvent extraction. Lack of solvent stability and chemical stability of most commercially available membranes is limiting the utilization of the above mentioned membrane technologies. This dissertation was primarily focused on developing solvent resistant hollow fiber and flat film membranes for separation and purification of organic-solvent-based process streams.

Available porous polymeric supports (Polypropylene (PP), Polyethersulfone (PES) and Nylon) suitable for the required solvent-stable applications were chosen first and then the supports were modified to satisfy the requirements for the applications. Membrane …

Enhancement Of Fluidization And Filtration Using Nanoparticle Agglomerates And Aerogels, Jose A. Quevedo

Dissertations

Previous works have classified the fluidization behavior of nanoparticles as Agglomerate Particulate Fluidization (APF) and Agglomerate Bubbling Fluidization (ABE). These fluidization behaviors are quite different in regard to the fluidized bed expansion, the presence of bubbles and the smoothness of the bed surface, with APF nanopowders showing a much more homogeneous fluidization and a much better dispersion than ABE nanopowders which are generally very difficult to fluidize and show vigorous bubbling. In the present work, the fluidization of APF as well as ABF nanopowders is studied in depth, both conventionally, and in the presence of extemal assistance; several related topics …

Reactive Modification And Crystallization Behavior Of Foamed Poly(Butylene Terephthalate), Byeong Joon Jeong

Dissertations

The objective of this study is to investigate the feasibility of preparing low density foams based on poly(butylene terephthalate) (PBT) through modification of its molecular structure and rheological characteristics by reactive extrusion. The scientific and/or engineering interpretation of the experimental data was based on fundamentals of extrusion, crystallization mechanisms, as well as information on reactivity and tendency toward degradation of PBT.

As a preliminary study, the extrusion foaming behavior of a commercial linear semi-crystalline PBT with a chemical blowing agent (CBA) was investigated. Foam characteristics were functions of extrusion operational variables, such as die set temperature and screw speed. Gas …

Solubility In Supercritical Carbon Dioxide, Syed Asif Abdullah

Theses

The different techniques used for the determination of the solubility of compounds in supercritical carbon dioxide are described. A comparative study is made of the methods used in the measurement of the concentration of benzoic acid and caffeine in supercritical carbon dioxide. The difference in measurement techniques did not have much effect on the solubility data at lower pressures. However, at higher pressures, the solubility data obtained by different techniques began to deviate from each other.

Further, the method used by different researchers in generating the solubility data in supercritical carbon dioxide is also discussed. A number of data sheets …

Functionalization Of Nanoclays Through Exchange Reactions, Jin Uk Ha

Theses

A cationic clay (sodium-montmorillonite, MMT) and an anionic clay (hydrotalcite, HT) were treated with two phosphonium based ionic liquids (ILs) and a commercial corrosion inhibitor. Clay modification was examined by TGA, FTLR and WXRD. The cationic clay modified with both ILs had similar thermal stabilities since they contained the same cation although the original anions were different. The thermal stability of the modified clays was higher than that of a commercial organoclay and of clays modified in our group with smaller MW pyridinium and imidazolium based cations. 10 wt% of interchanged cation was found under selected time/temperature treatment conditions.

Clays …

Jet Assisted Fluidization Of Nanoparticle Agglomerates, Ayokunle O. Omosebi

Theses

Fluidization serves as a primary operation used to disperse, handle and process nanoparticles, but due to the complications involved with achieving homogenous fluidization of the agglomerates of nanoparticles, several methods have been developed to assist their conventional mode of fluidization.

In this work, the conventional mode of fluidization was coupled with secondary gas flow emerging from a micro jet nozzle. The effect of the jet on the fluidization behavior of various APF and ABF nanopowders was studied and compared with the pure conventional fluidization mode. Generally, experiments were conducted to find the optimal operation of the jet by varying parameters …

Inverse Solid-Liquid Fluidization Of Aerogel Granules And Its Application In Removing Oil From Water, Gaurav Babubhai Patel

Theses

Fluidization is a very well known unit operation used in the chemical industry for various purposes. Inverse solid-liquid fluidization, where the solid particles to be fluidized are less dense than the fluid, is one of the several different kinds of fluidization being studied for its potential in industrial applications. The present work focuses on finding the hydrodynamic characteristics (minimum fluidization velocity, bed expansion and pressure drop) of an inverse fluidized bed of aerogel granules and using this system to remove oil from an oil-water mixture. The solid particles employed for this study are low density (100 kg/m³) surface …

How Does The Coupling Of Secondary And Tertiary Interactions Control The Folding Of Helical Macromolecules?, Vikas Varshney, Gustavo A. Carri

College of Polymer Science and Polymer Engineering

The authors study how the simultaneous presence of short-range secondary and long-range tertiary interactions controls the folding and collapse behavior of a helical macromolecule. The secondary interactions stabilize the helical conformation of the chain, while the tertiary interactions govern its overall three-dimensional shape. The authors have carried out Monte Carlo simulations to study the effect of chain length on the folding and collapse behavior of the chain. They have calculated state diagrams for four chain lengths and found that the physics is very rich with a plethora of stable conformational states. In addition to the helix-coil and coil-globule transitions, their …

An Improved Model For Calculating Heats Of Dilution And Equilibrium Constants For High Temperature Aqueous Electrolyte Solutions, Xiaoyun Lin

Theses and Dissertations

At high temperatures, the properties of aqueous electrolyte systems differ markedly from those at 25°C. For mixed-electrolyte dilute solutions at high temperatures, the degree of ion-association is sufficiently large that the association equilibrium must be incorporated in any model describing the solutions. These association reactions usually do not occur to a measurable extent at room temperature. Oscarson and co-workers have designed a correlation model based on the excess Gibbs energy which can correlate log K and ∆H values as well as the heats of dilution for aqueous electrolyte systems as a function of temperature (T) and ionic strength (I) from …

High-Frequency Ultrasound Drug Delivery And Cavitation, Mario Alfonso Diaz

Theses and Dissertations

The viability of a drug delivery system which encapsulates chemotherapeutic drugs (Doxorubicin) in the hydrophobic core of polymeric micelles and triggers release by ultrasound application was investigated at an applied frequency of 500 kHz. The investigation also included elucidating the mechanism of drug release at 70 kHz, a frequency which had previously been shown to induce drug release. A fluorescence detection chamber was used to measure in vitro drug release from both Pluronic and stabilized micelles and a hydrophone was used to monitor bubble activity during the experiments. A threshold for release between 0.35 and 0.40 in mechanical index was …

Mechanical Characterization Of Spherical Hydrogels: Contact Diameter Measurement, Joshua Bunch

Opportunities for Undergraduate Research Experience Program (OURE)

In an effort to develop new ophthalmic treatments revolving around the ocular lens, the mechanical characteristics of natural ocular lenses and synthetic models must be determined and compared. One mechanical characteristic that is necessary when making comparisons is the variation of contact circle diameter or contact area with varying strains. A method was used in this experiment to measure the varying contact circle diameter of spherical hydrogels at strains up to 15%. This method could be used to estimate the varying contact diameter of other similar materials such as natural ocular lenses if the precision of the method is improved. …

Cell Bank Characterization And Fermentation Optimization For Production Of Recombinant Heavy Chain C-Terminal Fragment Of Botulinum Neurotoxin Serotype E (Rbonte(HC): Antigen E) By Pichia Pastoris, Jayanta Sinha, Mehmet Inan, Sarah Fanders, Shinichi Taoka, Mark Gouthro, Todd Swanson, Rick Barent, Ardis Barthuli, Bonnie M. Loveless, Leonard A. Smith, Theresa Smith, Ian Henderson, John Ross, Michael M. Meagher

Papers in Biochemical Engineering

A process was developed for production of a candidate vaccine antigen, recombinant C-terminal heavy chain fragment of the botulinum neurotoxin serotype E, rBoNTE(H_c)in Pichia pastoris. P. pastoris strain GS115 was transformed with the rBoNTE(H_c) gene inserted into pHILD4 Escherichia coli—P. pastoris shuttle plasmid. The clone was characterized for genetic stability, copy number, and BoNTE(H_c) sequence. Expression of rBoNTE(H_c) from the Mut⁺ HIS4 clone was confirmed in the shake-flask, prior to developing a fed-batch fermentation process at 5 and 19 L scale. The fermentation process consists of a glycerol growth phase in …

Protection With Recombinant Clostridium Botulinum C1 And D Binding Domain Subunit (Hc) Vaccines Against C And D Neurotoxins, Robert P. Webb, Theresa J. Smith, Patrick M. Wright, Vicki A. Montgomery, Michael M. Meagher, Leonard A. Smith

Michael Meagher Publications

Recombinant botulinum Hc (rBoNT Hc) vaccines for serotypes C1 and D were produced in the yeast Pichia pastoris and used to determine protection against four distinct BoNT C and D toxin subtypes. Mice were vaccinated with rBoNT/C1 Hc, rBoNT/D Hc, or with a combination of both vaccines and challenged with BoNT C1, D, C/D, or D/C toxin. Mice receiving monovalent vaccinations were partially or completely protected against homologous toxin and not protected against heterologous toxin. Bivalent vaccine candidates completely survived challenges from all toxins except D/C toxin. These results indicate the recombinant C1 and D Hc vaccines are not only …

A Simple Sol-Gel Processing For The Development Of High-Temperature Stable Photoactive Anatase Titania, Suresh Pillai, Declan Mccormack, John Colreavy

Articles

No abstract provided.

Mesophase Separation And Probe Dynamics In Protein-Polyelectrolyte Coacervates, A. Basak Kayitmazer, Himadri B. Bohidar, Kevin W. Mattison, Arijit Bose, Jayashri Sarkar, Akihito Hashidzume, Paul S. Russo, Werner Jaeger, Paul L. Dubin

Chemical, Biomolecular, and Materials Engineering Faculty Publications

Protein–polyelectrolyte coacervates are self-assembling macroscopically monophasic biomacromolecular fluids whose unique properties arise from transient heterogeneities. The structures of coacervates formed at different conditions of pH and ionic strength from poly(dimethyldiallylammonium chloride) and bovine serum albumin (BSA), were probed using fluorescence recovery after photobleaching. Measurements of self-diffusion in coacervates were carried out using fluorescein-tagged BSA, and similarly tagged Ficoll, a non-interacting branched polysaccharide with the same size as BSA. The results are best explained by temporal and spatial heterogeneities, also inferred from static light scattering and cryo-TEM, which indicate heterogeneous scattering centers of several hundred nm. Taken together with previous dynamic …

Thermal Conductivity Improvement In Carbon Nanoparticle Doped Pao Oil: An Experimental Study, Shadab Shaikh, Khalid Lafdi, Rengasamy Ponnappan

Chemical and Materials Engineering Faculty Publications

The present work involves a study on the thermal conductivity of nanoparticle-oil suspensions for three types of nanoparticles, namely, carbon nanotubes(CNTs), exfoliated graphite (EXG), and heat treated nanofibers (HTT) with PAO oil as the base fluid. To accomplish the above task, an experimental analysis is performed using a modern light flash technique (LFA 447) for measuring the thermal conductivity of the three types of nanofluids, for different loading of nanoparticles.

The experimental results show a similar trend as observed in literature for nanofluids with a maximum enhancement of approximately 161% obtained for the CNT-PAO oil suspension. The overall percent enhancements …

Effect Of Carbon Nanofiber Heat Treatment On Physical Properties Of Polymeric Nanocomposites—Part I, Khalid Lafdi, William Fox, Matthew Matzek, Emel Yildiz

Chemical and Materials Engineering Faculty Publications

The definition of a nanocomposite material has broadened significantly to encompass a large variety of systems made of dissimilar components and mixed at the nanometer scale. The properties of nanocomposite materials also depend on the morphology, crystallinity, and interfacial characteristics of the individual constituents. In the current work, vapor-grown carbon nanofibers were subjected to varying heat-treatment temperatures.

The strength of adhesion between the nanofiber and an epoxy (thermoset) matrix was characterized by the flexural strength and modulus. Heat treatment to 1800C∘ demonstrated maximum improvement in mechanical properties over that of the neat resin, while heat-treatment to higher temperatures demonstrated a …

The Shape Of Pulverized Bituminous Vitrinite Coal Particles, Jonathan P. Mathews, Patrick G. Hatcher, Alan W. Scaroni

Chemistry & Biochemistry Faculty Publications

The shape of pulverized bituminous coal particles (vitrinites) was determined by optical and laser light scattering. Vitrain samples were collected from obvious tree remains located in the ceilings of two Appalachian coal mines. Wet sieving produced narrow size cuts. The particles were determined to be oblong or blocky in shape, with average length-to-width ratio of 1.7 and sphericity of 0.78. They were analogous in shape to a square ended, rectangular "house brick". The two bituminous coals and different size cuts of each coal had essentially the same shape parameters. Characteristic heating times and terminal velocities were higher by 22 and …

Simulation Of The Oxygen Reduction Reaction At An Rde In 0.5 M H2So4 Including An Adsorption Mechanism, Qingbo Dong, Shriram Santhanagopalan, Ralph E. White

Faculty Publications

Oxygen reduction on the surface of a rotating disk electrode (RDE) in 0.5 M H₂SO₄ is simulated by including mass transfer, adsorption, and charge transfer. A generalized model for the adsorption and reaction of several species is introduced. The oxygen reduction reaction is simulated as a limiting case where oxygen is the only species adsorbed, and oxygen reduction is the only reaction that takes place on the surface of the electrode. The model is based on the Nernst–Planck equations for mass transfer and the Butler–Volmer equation for electrochemical kinetics. The simulated polarization curves capture the change in …

Modeling Li/CfX-Svo Hybrid-Cathode Batteries, Parthasarathy M. Gomadam, Donald R. Merritt, Erik R. Scott, Craig L. Schmidt, Paul M. Skarstad, John W. Weidner

Faculty Publications

A mathematical model is developed that predicts the voltage-capacity behavior of a primary lithium battery containing a hybrid cathode, which combines the high energy density of carbon monofluoride (CF_x) and the higher power density of silver vanadium oxide (SVO). The model is developed using material balances and kinetic expressions for each material, extracting kinetic and thermodynamic parameters from data collected on CF_x and SVO batteries, and then integrating this information into a hybrid system. The full model is validated by comparing simulations to experimental data on Li/CF_x-SVO hybrid-cathode batteries of various designs and for a …

Development Of Ruthenium-Based Catalysts For Oxygen Reduction Reaction, Lingyun Liu, Hansung Kim, Jong-Won Lee, Branko N. Popov

Faculty Publications

A process was developed to synthesize ruthenium-based chelate (RuN_x) electrocatalysts for the oxygen reduction reaction, using RuCl₃ and propylene diammine as the Ru and N precursors, respectively. High-temperature pyrolysis has a critical role in the formation of the catalytic Ru–N sites for oxygen reduction. The RuN_x catalyst modified in the presence of nitrogen-containing organic exhibited comparable catalytic activity and selectivity for oxygen reduction to the carbon-supported Pt catalyst in acidic media. The catalyst generates less than 2% hydrogen peroxide during oxygen reduction.

Novel Pemfc Cathodes Prepared By Pulse Deposition, Subasri M. Ayyadurai, Yoon-Seok Choi, Prabhu Ganesan, Swaminatha P. Kumaraguru, Branko N. Popov

Faculty Publications

A pulse electrodeposition method of preparing thin platinum catalyst layers for polymer electrolyte membrane fuel cell (PEMFC) cathodes has been developed through surface activation of the gas diffusion layer (GDL) by a wetting agent. The performance of the catalyst layer was optimized by wetting agent type, immersion time in the wetting agent, and pulse deposition parameters such as total charge density, peak current density, and duty cycle ratio. The T_off time played a more important role than the T_on time in determining the electrode characteristics such as high concentration of Pt, smaller particle size, and loading. Pt cathodes …