Chemical Engineering Commons^™

Synthesis Of Li_(1+X)Mn_2o_4 Cathode Material For Lithium-Ion Batteries With Solution Method, Pei Song Liu, Sing Quarn Liu, Qing Li, Zhao Yong Chen, Bai Lan Zhang, Zuo Long Yu

Journal of Electrochemistry

The cathode materials Li 1+x Mn 2O 4 were prepared with citric acid complexing and solution impregnating methods.Structure characterization and specific surface area test were performed by means of XRD,BET methods ,the influences of calcination temperature,Li/Mn molar ratio and raw materials on the structure and electrochemical capacity of samples have beem examined.The results showed that the Li/Mn molar ratio and calcimation temperature were the key factors affecting the electrochemical capacity of cathode materias.The optimum conditions for synthesis of Li 1+x Mn 2O 4 cathode material were 0≤x≤0.05 and calcined at 750°C.The initial capacity of the sample reached 120 mAh/g and …

A New Method For The Preparation Of The Electrodes With Very Low Platinum Loading Used In Proton Exchange Membrane Fuel Cell, Zhi-Gang Shao, Bao-Lian Yi, Ming Qiao Ya-Guang Han, Hao Liu, Jing-Rong Yu

Journal of Electrochemistry

Research and development on low platinum loading electrode is very important in reducing the cost of proton exchange membrane fuel cell(PEMFC)stack.This paper has put forward a new method to prepare the electrode of PEMFC. The pore forming substances were used in this methd. The low platinum loading electrodes (0.02 mgPtcm -2 )have already been prepared with the method. Compared with the traditional method, the new method is simple, cheep, and easy to scale up. The superior composition of the electrodes is catalyst: pore forming substance: Nafion= 331. The performance of a single cell using this kind of electrodes and Nafion …

The Electro-Catalytic Oxidation Of Hcooh On Electrodeposited Pd Electrode, Quan Zhou, Cunzhong Zhang, Xiaolin Lu, Zhongda Wu

Journal of Electrochemistry

The coherent electroplates were prepared by electro depositing Pd on supporting materials glassy carbon. The surface morphology of the electrodes was examined by SEM. The electro oxidation of HCOOH in HClO 4 solution was investigated by using cyclic voltammetry. The results show that the deposited conditions in the preparation of electrodes by electro depositing Pd affect the electrodes electro catalytic activity to the oxidation of HCOOH. The platinized Pd electrode on GC substrates using large current density is of higher catalytic activity to the oxidation of HCOOH than Pd electrode. The electro catalytic activity of PdO formed on the Pd …

The Effect Of Anode Thickness In Sofcs With Anode Supported Ysz Film, Yi Huang Zhang, Yi Jiang, Zi Gui Lu, Yong-Lai Dong, Jing-Wang Yan

Journal of Electrochemistry

Solid oxide fuel cells with supported yttria stabilized zirconia electrolyte films on anode substrates of various thickness have been fabricated. The electrochemical performances of the SOFCs have been examined. The results showed that the cell performance was limited by the anodic overpotential, which is caused mainly by a concentration polarization when the anode substrate is thick. The anodic overpotential was reduced obviously as the thickness of anode substrate was decreased. As a result, the performance of the SOFC cell was improved. With a 0.5 mm anode substrate, a SOFC cell produced a power density about 0.19 W/cm 2 at 800 …

Fermentation Strategies For Recombinant Protein Expression In The Methylotrophic Yeast Pichia Pastoris, Wenhui Zhang, Mehmet Inan, Michael M. Meagher

Papers in Biochemical Engineering

Fermentation strategies for recombinant protein production in Pichia pastoris have been investigated and are reviewed here. Characteristics of the expression system, such as phenotypes and carbon utilization, are summarized. Recently reported results such as growth model establishment, application of a methanol sensor, optimization of substrate feeding strategy, DOstat controller design, mixed feed technology, and perfusion and continuous culture are discussed in detail.

Membrane-Based Sorbent For Heavy Metal Sequestration, Dibakar Bhattacharyya, Leonidas G. Bachas, Lawrence Cullen, Jamie A. Hestekin, Subhas K. Sikdar

Chemical and Materials Engineering Faculty Patents

A process is provided for making membrane-based sorbents with enhanced binding activity that are particularly useful for heavy metal sequestration. The process includes the step of selectively hydrolyzing a polyacetylated membrane in order to deacetylate a surface layer of said membrane and expose free hydroxyl groups. This is followed by the oxidizing of the hydroxyl groups to aldehyde groups. This is then followed by the attaching of a polycarboxylic acid such as a polyamino acid, polyalkenoic acid or polypeptide to the membrane through the aldehyde groups. Preferably, the hydrolyzing step is completed under alkaline conditions and the oxidizing step is …

Enhanced Adhesion Between A Vapor Deposited Metal And An Organic Polymer Surface Exhibiting Tailored Morphology, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

Enhanced adhesion between a vapor deposited metal and an organic polymer surface is achieved without utilizing any intermediate surface preparatory steps. The morphology of the polymer surface is tailored to produce mounds and dimples on the surface which leads to a mechanically tougher, interdigitated metal/polymer interface. In the preferred embodiment, a solution of a solvent or solvent system and two or more polymer precursors or polymers or combinations thereof are cast in a film on a substrate and heated to spontaneously form a rough surface due to phase separation. The surface topography of such a film consists of characteristic mounds …

Micro Goniometer For Scanning Microscopy, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A goniometer for performing scanning probe microscopy on a substrate surface is disclosed. The goniometer has a cantilever, having a cantilevered end and a supported end and a tip disposed at the cantilevered end of the cantilever. The goniometer also has a block disposed at the supported end of the cantilever. The block has at least one pair of piezoelectric layers, a pair of electrodes disposed about each individual piezoelectric layer such that varying a potential difference applied between the individual electrodes of a pair of electrodes causes the corresponding piezoelectric layer to deform, and a first insulating material disposed …

9. Oskar Friedrich Olaj, Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.

9. Oskar Friedrich Olaj, Otto Vogl

Otto Vogl

No abstract provided.

Facile Sol-Gel Synthesis Of Porous Silicas Using Poly(Propylene)Imine Dendrimers As Templates, Gustavo F. Larsen, Edgar Lotero, Manuel Marquez

Gustavo Larsen Publications

Commercially available poly(propylene)imine (DAB-Am-32 and DAB-Am-64) dendrimers were used as single-molecule templates to tailor the porosity of silicas via a nonacidic sol-gel method. X-ray diffraction on both the as-prepared (oven-dried at 373 K) and the calcined (833 K) materials revealed that modest contraction took place on template removal and that the cavities created did not achieve three-dimensional ordering under the current synthesis conditions. Transmission electron microscopy of “Pt-stained” samples supported this picture. A modified Horvath–Kawazoe analysis of the argon adsorption isotherms indicated that DAB-Am-64 is a much more effective template than DAB-Am-32. Pyrolysis and oxidation protocols for template removal are …

A Multiscale, Bayesian And Error-In-Variables Approach For Linear Dynamic Data Rectification, Sridhar Ungarala, Bhavik R. Bakshi

Chemical & Biomedical Engineering Faculty Publications

A multiscale approach to data rectification is proposed for data containing features with different time and frequency localization. Noisy data are decomposed into contributions at multiple scales and a Bayesian optimization problem is solved to rectify the wavelet coefficients at each scale. A linear dynamic model is used to constrain the optimization problem, which facilitates an error-in variables (EIV) formulation and reconciles all measured variables. Time-scale recursive algorithms are obtained by propagating the prior with temporal and scale models. The multi-scale Kalman filter is a special case of the proposed Bayesian EIV approach.

10. Dietrich Braun, Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.

Development In The Petroleum Sub-Sector And Their Impacts On Nigerian Economy., I. P. Ojinnaka

Bullion

The development of the petroleum industry has had both negative and positive impacts on the Nigerian economy. Two schools of thought can be examined. First, that positive impacts outweigh the negative, and secondly, the inverse. The paper will examined the impacts and analyzed the positive ones. From the approach of the study it is clear that the petroleum industry has had both negative and positive impacts on the Nigerian economy. Nigeria without petroleum could be like any other country without oil or gas, that is, import dependent. However, Nigeria with oil is the best thing that could have happened to …

10. Dietrich Braun, Otto Vogl

Otto Vogl

No abstract provided.

Comparison Of Charged Sheets And Corrected 3-D Ewald Calculations Of Long-Range Forces In Slab Geometry Electrolyte Systems With Solvent Molecules, Richard L. Rowley, Paul S. Crozier, Eckhard Spoht, Douglas Henderson

Faculty Publications

Two methods of calculating long-range intermolecular potentials are compared for an approximately 3 M aqueous electrolyte solution confined between two charged surfaces. We investigate the ionic density profiles using the charged-sheets method and the corrected three-dimensional (3D) Ewald method at two different system sizes and also compare the Coulomb forces directly. The corrected 3D Ewald method is recommended for the calculation of long-range potentials in systems of this nature because it is less system size dependent than the charged sheets method and the resultant forces are more consistent with periodic boundaries. However, the charged-sheets method for estimating long-range potentials in …

11. Binglin He, Otto Vogl, Frank C. Ho (He Zhenchi)

Emeritus Faculty Author Gallery

No abstract provided.

11. Binglin He, Otto Vogl, Frank C. Ho (He Zhenchi)

Otto Vogl

No abstract provided.

Calibration Of Optical Digital Fragmentation Measuring Systems, Norbert H. Maerz, Wei Zhou

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Optical granulometry systems like WipFrag are required to measure fragments in situ. That is to say, the fragments are in piles where sorting takes place, where fragments are partially overlapped, and where fines may not be seen because they fall in and behind the coarser fragments, or where the fines are simply too small to be seen. As a result, optical systems tend typically to overestimate the size of the distribution, and underestimate the variability of the distribution. The wider the size distribution being measured, the more severe the problem is. This paper presents the results of a study that …

The Impact And Fate Of Aqueous Sodium Nitrate On Hydrocarbon Flames, Ann Marie Flynn

Dissertations

This study examined the impact and fate of sodium (fed as an aqueous nitrate solution) in fuel-rich methane/air and methane/methyl chloride/air flames as a function of equivalence ratios that experienced diffusion of air from the surroundings. The flames were stabilized on a slotted, uncooled burner. The data set was divided into profiles of relative sodium atom concentrations, temperatures, and selected stable species concentrations. The flames were simulated using a modified version of the Sandia FORTRAN program for modeling steady laminar one-dimensional premixed flames complete with detailed mechanisms. The results showed that maximum sodium atom concentration in the flame is decreased …

Endotoxin Removal From Protein Solutions By Immobilized Metal Ion Affinity Chromatography, Yun Kang

Dissertations

In the biotechnology/pharmaceutical industry, the removal of endotoxins from final protein product has always been a challenge. A novel method for endotoxin removal from protein solutions, immobilized metal (ion) affinity chromatography (IMAC) has been developed in this study. Fe³⁺ was charged to a chelating gel that contains iminodiacetic acid (IDA). The IDA- Fe³⁺ IMAC column was exploited to remove endotoxin from protein solutions. This method involves the adsorption of the endotoxin on IMAC column. More than 99% endotoxin is removed and protein yield is higher than 90%. IDA-Fe³⁺ IMAC has proved to be an economical and efficient …

Fluidization And Soot Filtration In A Rotating Fluidized Bed, Gui-Hua Qian

Dissertations

A horizontal rotating fluidized bed (RFB) has been investigated for the removal of soot from diesel engine exhaust. This requires necessitating an understanding of the nature of fluidization, particle mixing and filtration in the RFB.

In an RFB, particles are subject to a centrifugal force which can be much larger than the force of gravity. Therefore the Geldart classification for conventional fluidized beds must be modified for rotating fluidized beds. A theoretical analysis shows that group A particles (minimum bubbling velocity U_mb > minimum fluidization velocity U_mf can shift to group B U_mb = U_mf and group …

An Integrated Membrane-Based Chromatographic Process For Biomolecule Isolation And Purification, Xiaoping Dai

Dissertations

Biomolecules obtained from fermentation and cell-culture processes are present in low concentrations in a complex medium/broth. For intracellular products, cells are first harvested. Subsequently, cell lysis and homogenization are undertaken to produce a homogenate. The biomolecules are next separated from the cell debris by lysate clarification. For extracellular products, the biomolecules are separated from the whole cells by clarification. The overall yield is reduced with each additional step. As the cost of bioseparation process accounts for 50-80% of the final product cost, innovations in and improvement of bio-downstream processing are greatly needed.

In this research, a cyclic process integrating a …

Numerical Studies Of Deep Bed Filtration, Chan-Gyun Shin

Theses

Deep bed filtration is a process used to separate small solid particles suspended in a fluid by using granular solids as the collecting medium. The filter efficiency depends on many parameters such as the Reynolds number, particle drag coefficient, the ratio of the diameter of injected, and filter particles, etc.

In the present work we model the porous media flow (solution of the Navier-Stokes equations) by using a computer code developed by Dr. P. Singh and we restrict our analysis to the case of two dimensional periodic porous media. The computational domain is discretized using the finite element method. In …

Feasibility Study Of Rotating Fluidized Bed As A Dry Coater And Granulater, Manish Sawhney

Theses

This study is directed at enhancing our understanding of the mechanism of dry coating and granulation in a rotating fluidized bed (RFB). The main objective was to study the feasibility of the coating and granulation processes using an REB, both quantitatively and qualitatively.

A force balance and kinetic model is applied to explain the coating phenomenon and also to investigate why coating takes place in certain particle material systems and not in others. An equation for the resultant velocity with which one particle collides with another has been suggested for the rotating fluidized bed coater. A condition, which predicts whether …

Powder Microelectrode Modified With Nafion-Os(Bpy)_3~( 2+) And Pvp Composite And Its Catalysis For No_2 - Reduction, Pei-Fang Liu, Jia-Wei Yan

Journal of Electrochemistry

The modified powder microelectrode was prepared by etching a Pt (0.1 mm diameter) disk microelectrode and filling in thus formed cavity with Nation_Os(bpy) 3 2+ /PVP composite modified carbon powder. The composite modified powder microelectrode showed cyclic voltammetric behaviors changing with the mole ratio (denoted X) of SO 3 - to Os(bpy) 3 2+ in Nafion. When X=3, a single pair of current peaks appeared near 0.6V (vs. SCE) due to Os(bpy) 3 2+/3+ redox couple. In contrast, for X=20, a pair of additional current peaks occurred near 0.4V. Both X=3 and X=20 modified powder microelectrodes strongly catalyzed the first …

Template Synthesis And Uv-Vis Absorption Spectra Of The Nanowire Arrays Of Cadmium Chalcogenides

Journal of Electrochemistry

XU Shi_min, XUE Kuan_hong , KONG Jing_lin, SUN Dong_mei, FENG Yu_ying, LU Hai_yan (Dept. of Chem., Nanjing Normal Univ., Nanjing 210097, China) WANG Guang_hou (National Laboratory of Solid State Microstructures, Nanjing Univ., Nanjing 210093, China)The porous alumina membrane formed in the anodic oxidation of highly pure aluminum foil has attracted a great deal of attention in recent years [1] . It can be served as a desired template to prepare nanometer scale materials [2] due to its unique structure of discrete and cylindrical nanopores, paralleled one another, with the homogeneous size and distribution [3] . Chalcogenide semiconductors have promising prospect …

Activated Carbon And Process For Making Same, Francis John Derbyshire, Marit Jagtoyen

Chemical and Materials Engineering Faculty Patents

A process is described for the manufacture of activated carbon in the form of a powder, as granules or as extrudates. The process includes treating a biomass feedstock, such as woods, coconut shells, fruit pits, peats, lignites and all ranks of coal with a processing agent and an activation agent. The processing agent may be a natural or synthetic monomer, oligomer, polymer or mixtures thereof capable of interacting or co-polymerizing with the biomass feedstock. The activation agent may be, for example, phosphoric acid, zinc chloride or mixtures thereof. A high surface area, high hardness extruded activated carbon may be produced …

Piezoelectric Sensors / Actuators For Use In Refractory Environments, Hendrik J. Viljoen, Barend R. Jooste

Papers in Reaction Kinetics

pierozlectric properties over a large temperature range of from room temperature to approximately 1360 degrees centigrade. The piezarlecttic system is sequentially comprised of a first electrically conductive layer, a layer of (Ta,O,) in other than a rnonoclinic phase, ipreferably onhorhombic demonstrating small x-ray crystalopraphic and peaksi. and a second slecttically conductive layer A preferred method of fabrication involves sputter deposition of both said layer of (Ta,O) md said second electrically conductive layer.

The Design Of A Chemical Plant Using Hysys Simulation Program, Michael Randolph Vaughan

Chancellor’s Honors Program Projects

No abstract provided.