Chemical Engineering Commons^™

Synthesis Of Limn2O4-ΔClΔ Cathode Material By Like-Sol-Gel Methode, Zhao-Yong Chen, Yi He, Xing-Quan Liu, Zhi-Jie Li, Zuo-Long Yu

Journal of Electrochemistry

LiMn₂O_4-δCl_δ was synthesized by like sol gel methode, with calculated LiOH·H₂O, Mn(No₃)₂⋅6H₂O and LiCl·H₂O, and made electrochemical test with these compounds as positive materials. Result demostrated that LiMn₂O_4-δCl_δ cathode material has exellent stability and nearly no capacity loss after reaching stability.

Adsorption And Oxidation Of Ethanol On Nm-Pt/Gc Electrode Ii. Eqcm And In-Situ Ftir Spectroscopic Studies In Acid Media, Guo-Liang Chen, Sheng-Pei Chen, Zhi-You Zhou, Chun-Hua Zhen, Shi-Gang Sun

Journal of Electrochemistry

The adsorption and oxidation of ethanol on nm Pt/GC electrode in acid solutions containing 0.1 mol·L ^-1 H₂SO₄ +0.1 mol·L ^-1 CH₃CH₂OH was investigated by using cyclic voltammetry, EQCM and in situ FTIR spectroscopy. The experimental results demonstrated that the oxidation of CH₃CH₂OH is closely relaed to solution acidity and oxygen species on electrode surface; CH₃CH₂OH was oxidized on nm Pt/GC electrode in acidic media via a dual path reaction mechanism, i.e . CH₃CH₂OH may be oxidized into CO₂ through …

Immunosorbents With Developed Binding Efficiency And Method Of Manufacture , William H. Velander

Department of Chemical and Biomolecular Engineering: Patents

The antitope of an antibody is masked with a masking agent, followed by immobilization on a support. The masking agent is then eluted to produce an improved immunosorbent, which is capable of binding more than double the amount of an antigen than existing immunosorbents having the same antibody bound at the same density. Preferably, the masking agent is an antigen or other compound having an epitope for which the antitope of the bound antibody has an avidity. In a preferred embodiment, greater than 30% of the bound antibodies maintain the same vicinity as when unbound for specific antigen or hapten …

Prediction Of Axial Liquid Velocity Profile In Bubble Columns, Yuanxin Wu, M. (Muthanna) H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Liquid Flow and Mixing Behavior in Bubble Columns is Partially Described by Means of Global Liquid Recirculation Velocity Profile. Due to the Complex Character of the Flow in Bubble Columns, the Prediction of the Axial Liquid Circulation is Still a Difficult Task. in This Work, the Following Correlation is Proposed for the Liquid Recirculation Profile: VLO/ VL(R)= 1 - 2.65 * N0.44 * C[R/r] 2.65, N0.442,c , Where N and C Are the Gas Radial Holdup Profile Parameters Evaluated by the Correlations Proposed by Wu, Ong and Al-Dahhan (Chemical Engineering Science, 56 (2001) 1207-1210). N = 2.188 X 103 …

Gas Holdup In A Trayed Cold-Flow Bubble Column, A. Kemoun, N. Rados, F. Li, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic', P. L. Mills, T. M. Leib, J. J. Lerou

Chemical and Biochemical Engineering Faculty Research & Creative Works

An Experimental Study Was Performed to Investigate the Effect of Sieve Trays on the Time-Averaged Gas Holdup Profiles and the overall Gas Holdup in a Cold-Flow Bubble Column that Was Scaled-Down from a Commercial Unit. Γ-Ray Computed Tomography (CT) Was Used to Scan the Column at Several Axial Locations in the Presence and Absence of Trays from Which the Local Variation of the Gas Holdup Was Extracted. the overall Gas Holdup Was Also Determined using the Same Configuration by Comparing the Expanded and Static Liquid Heights. Air and Water Were Used as the Gas-Liquid System. the Superficial Gas and Liquid …

Modeling And Analysis Of The Electrokinetic Mass Transport And Adsorption Mechanisms Of A Charged Adsorbate In Capillary Electrochromatography Systems Employing Charged Nonporous Adsorbent Particles, B. A. Grimes, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

Mass-transfer systems based on electrokinetic phenomena (i.e., capillary electrochromatography (CEC)) have shown practical potential for becoming powerful separation methods for the biotechnology and pharmaceutical industries. A dynamic mathematical model, consisting of the momentum balance and the Poisson equations, as well as the unsteady-state continuity expressions for the cation and anion of the background electrolyte and of a positively charged analyte (adsorbate), is constructed and solved to determine quantitatively the electroosmotic velocity, the electrostatic potential, the concentration profiles of the charged species in the double layer and in the electroneutral core region of the fluid in the interstitial channels for bulk …

Comparison Of Single- And Two-Bubble Class Gas-Liquid Recirculation Models - Application To Pilot-Plant Radioactive Tracer Studies During Methanol Synthesis, Puneet Gupta, Muthanna H. Al-Dahhan, Milorad P. Dudukovic, Bernard A. Toseland

Chemical and Biochemical Engineering Faculty Research & Creative Works

Radioactive Gas Tracer Measurements Conducted during Liquid-Phase Methanol Synthesis from Syngas in a Pilot-Scale Slurry Bubble Column at the Alternate Fuels Development Unit (AFDU), La Porte Have Been Compared with Simulations from Two Mechanistic Reactor Models - Single-Bubble Class Model (SBCM) and Two-Bubble Class Model (TBCM). the Model Parameters Are Estimated from an Independent Sub-Model Gas and Liquid Recirculation, and the Long-Time-Averaged Slip Velocity between the Gas and Liquid/slurry in the Column Center Can Be as High as 50-60 Cm/s Depending on the Operating Conditions. Comparison of Experimental Data with Simulation Results from the Two Models Indicates that Accurate Description …

Effects Of External Electric Field On The Interfacial Properties Of Weakly Dipolar Fluid, V. B. Warshavsky, T. V. Bykov, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

In the framework of modified mean-field density-functional theory, effects of a uniform electric field on the interfacial properties of a model dipolar fluid are studied. Both density and orientational order-parameter profiles of the planar vapor-liquid interface are obtained as a function of the field strength. For the dipolar fluids with reduced dipole moment μ₀^*0^*E*/T*!1) can shift the surface tension by few percent. We also find that the electric field actually reduces the thermodynamical surface tension but enhances the mechanical surface tension at the equimolar dividing surface. To detect these field effects on …

Predictions Of Radial Gas Holdup Profiles In Bubble Column Reactors, Yuanxin Wu, Boon Cheng Ong, M. (Muthanna) H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Gas Holdup and its Profile Are Important Parameters to Be Characterized in Bubble Column Reactors. Proper Prediction of the Radial Gas Holdup Profiles is Necessary for Determining Liquid Mixing, Flow Regime Transition, Heat and Mass Transfer. in This Study, the Following Gas Holdup Profile Form, Which Can Be Fitted to the Observed Holdup Profiles, is Proposed: EG = EG (N + 2/n + 2 - 2c) [1 - C(R/R)n]. the Parameters N and C Needed to Describe the Gas Holdup Profile Are Correlated with Appropriate Dimensionless Groups. N = 2.188 X 103 ReG-0.598 Frg0.146 MoL-0.004, C = 4.32 X 10-2 …

Testing Of Semiconductor-Based Adsorption Modified Photosensitive (Samp) Sensor For Response To Toluene, Ashish Agrawal

Theses

The response of semiconductor-based adsorption modified photosensitive sensor is based on the dye-enhanced photoconductivity of a CdS semiconducting film. The change in this photoconductivity is brought about when organic molecules are sorbed onto the dye-coated surface. The response is related to the overlap in the infrared spectrum of the dye with that of the analyte.

This research was carried out to study the response of the sensor to a typical hydrocarbon, toluene. The sensor was tested for its response to concentrations of toluene ranging from 2.6 ppm to 200 PPM in nitrogen. The sensor was tested under non-flow conditions and …

Hydrodynamics Of Churn Turbulent Bubble Columns: Gas-Liquid Recirculation And Mechanistic Modeling, Puneet Gupta, Booncheng Ong, Muthanna H. Al-Dahhan, Milorad P. Dudukovic, Bernard A. Toseland

Chemical and Biochemical Engineering Faculty Research & Creative Works

A Phenomenological (Mechanistic) Model Has Been Developed for Describing the Gas and Liquid/slurry Phase Mixing in Churn Turbulent Bubble Columns. the Gas and Liquid Phase Recirculation Rates in the Reactor, Which Are Needed as Inputs to the Mechanistic Reactor Model Are Estimated Via a Sub-Model Which Uses the Two-Fluid Approach in Solving the Navier-Stokes Equations. This Sub-Model Estimates the Effective Bubble Diameter in the Reactor Cross-Section and Provides a Consistent Basis for the Estimation of the Volumetric Mass Transfer Coefficients. the Strategy for the Numerical Solution of the Sub-Model Equations is Presented Along with the Simulation Results for a Few …

Corrosion And Dissolution Protection Of A Conductive Silver/Polymer Composite, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A conductive composite is described containing silver particles and a polymer which covers each silver particle and wherein a heterocyclic organic compound containing nitrogen such as benzotriazole (BTA) is present to reduce Ag dissolution and ion mobility by forming a water insoluble complex with the Ag ion. The invention overcomes the problem of silver dissolution or corrosion a conductive composite as a result of normal high Ag ion mobility in the presence of moisture and an electric field

System And Process For Producing Biodiesel Fuel With Reduced Viscosity And A Cloud Point Below Thirty-Two (32) Degrees Fahrenheit, Hossein Noureddini

Department of Chemical and Biomolecular Engineering: Patents

Triglycerides are reacted in a liquid phase reaction with a homogeneous basic catalyst and alcohol, such as ethanol or methanol. The reaction yields a spatially separated two phase result with an upper located non-polar phase consisting principally of transesterified triglycerides and a lower located phase consisting principally of crude glycerol and residual transesterified triglycerides. The transesterified triglycerides and/or glycerol phase is/are optionally, each separately passed through strong cationic ion exchanger(s) to remove anions, resulting in neutral product(s). The crude glycerol is then flashed to remove alcohol and is reacted with an etherifying agent, such as isobutylene or isoamylene, in the …

Electrically Conductive Polymeric Materials And Use Thereof, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

The present invention relates to electrically conductive polymer blend compositions comprising a non-conducting polymeric component and an electrically conducting polymeric component and specific applications to which the blend compositions can be put.

Attenuation Of Sound In Concentrated Suspensions: Theory And Experiments, Ashok S. Sangani, Peter D. M. Spelt, Michael A. Norato, Margaret S. Greenwood, Lawrence L. Tavarides

Biomedical and Chemical Engineering - All Scholarship

Ensemble-averaged equations are derived for small-amplitude acoustic wave propagation through non-dilute suspensions. The equations are closed by introducing effective properties of the suspension such as the compressibility, density, viscoelasticity, heat capacity, and conductivity. These effective properties are estimated as a function of frequency, particle volume fraction, and physical properties of the individual phases using a self-consistent, effective-medium approximation. The theory is shown to be in excellent agreement with various rigorous analytical results accounting for multiparticle interactions. The theory is also shown to agree well with the experimental data on concentrated suspensions of small polystyrene particles in water obtained by Allegra …

Cationic Surfactant Mediated Hybridization And Hydrophobization Of Dna Molecules At The Liquid/Liquid Interface And Their Phase Transfer, Murali Sastry, Ashavani Kumar, Mrunalini Pattarkine, Vidya Ramakrishnan, Krishna N. Ganesh

Faculty Works

Hybridization of complementary oligonucleotides mediated by a cationic surfactant at the water/hexane interface leads to hydrophobic, double-helical DNA which may be readily phase transferred to the organic phase and cast into thin films on solid substrates.

Linear-Nonequilibrium Thermodynamics Theory For Coupled Heat And Mass Transport, Yaşar Demirel, Stanley I. Sandler

Yaşar Demirel Publications

Linear-nonequilibrium thermodynamics (LNET) has been used to express the entropy generation and dissipation functions representing the true forces and flows for heat and mass transport in a multicomponent fluid. These forces and flows are introduced into the phenomenological equations to formulate the coupling phenomenon between heat and mass flows. The degree of the coupling is also discussed. In the literature such coupling has been formulated incompletely and sometimes in a confusing manner. The reason for this is the lack of a proper combination of LNET theory with the phenomenological theory. The LNET theory involves identifying the conjugated flows and forces …

Mathematical Modeling For Fabricating A Microstructure With A Pre-Specified Geometry Using Laser -Induced Chemical Vapor Deposition, Chaoyang Zhang

Doctoral Dissertations

Laser-induced chemical vapor deposition (LCVD) is an emerging new technique with many practical applications. To optimize the system for fabricating a microstructure with a pre-specified geometry in pyrolytic LCVD, a three-dimensional mathematical model is developed for predicting temperature distributions and laser dwell times across the substrate scanned by the laser beam. A microstructure is fabricated layer by layer, and for each layer the laser beam moves from one pixel to the next. The complicated correlations among temperature distribution, deposit growth rate, and laser dwell time are investigated. A purely heterogeneous reaction is assumed and any gas-phase transport is ignored.

A …

Evaluation Of The Precision Of Magnetic Resonance Phase Velocity Mapping For Blood Flow Measurements, George P. Chatzimavroudis, John N. Oshinski, Robert H. Franch, Peter G. Walker, Ajit P. Yoganathan, Roderic I. Pettigrew

Chemical & Biomedical Engineering Faculty Publications

Evaluating the in vivo accuracy of magnetic resonance phase velocity mapping (PVM) is not straightforward because of the absence of a validated clinical flow quantification technique. The aim of this study was to evaluate PVM by investigating its precision, both in vitro and in vivo, in a 1.5 Tesla scanner. In the former case, steady and pulsatile flow experiments were conducted using an aortic model under a variety of flow conditions (steady: 0.1–5.5 L/min; pulsatile: 10–75 mL/cycle). In the latter case, PVM measurements were taken in the ascending aorta of ten subjects, seven of which had aortic regurgitation. Each velocity …

Measurements Of The Average Properties Of A Suspension Of Bubbles Rising In A Vertical Channel, Ashok S. Sangani, Roberto Zenit, Donald L. Koch

Biomedical and Chemical Engineering - All Scholarship

Experiments were performed in a vertical channel to study the behaviour of a monodisperse bubble suspension for which the dual limit of large Reynolds number and small Weber number was satisfied. Measurements of the liquid-phase velocity fluctuations were obtained with a hot-wire anemometer. The gas volume fraction, bubble velocity, bubble velocity fluctuations and bubble collision rate were measured using a dual impedance probe. Digital image analysis was performed to quantify the small polydispersity of the bubbles as well as the bubble shape.A rapid decrease in bubble velocity with bubble concentration in very dilute suspensions is attributed to the effects of …

Numerical Simulation Of A Gas–Liquid Flow In A Fixed Bed, Ashok S. Sangani, Sangkyun Koo

Biomedical and Chemical Engineering - All Scholarship

A countercurrent gas–liquid flow through a fixed bed of spherical particles is examined numerically by solving the particle-scale equations governing the gas and liquid flows. The liquid is assumed to flow along the surface of the particles forming a thin film. The case of small gas flow rates is examined in detail first. In this limit the presence of the liquid film increases the gas pressure drop over its value for a dry bed by three mechanisms: The liquid film makes the apparent size of the particles larger, decreases the pore space for the gas flow, and, with its velocity …

Entropy Generation Method To Quantify Thermal Comfort, S. C. Boregowda, S. N. Tiwari, S. K. Chaturvedi

Mechanical & Aerospace Engineering Faculty Publications

The present paper presents a thermodynamic approach to assess the quality of human-thermal environment interaction and quantify thermal comfort. The approach involves development of entropy generation term by applying second law of thermodynamics to the combined human-environment system. The entropy generation term combines both human thermal physiological responses and thermal environmental variables to provide an objective measure of thermal comfort. The original concepts and definitions form the basis for establishing the mathematical relationship between thermal comfort and entropy generation term. As a result of logic and deterministic approach, an Objective Thermal Comfort Index (OTCI) is defined and established as a …

Electrochemical Generation Of Superoxide In Room-Temperature Ionic Liquids, Inas M. Alnashef, Matthew L. Leonard, Matthew C. Kittle, Michael A. Matthews, John W. Weidner

Faculty Publications

We have demonstrated that superoxide ion can be generated electrochemically in room-temperature ionic-liquid solvents. In the absence of impurities, cyclic voltammetry showed that the super oxide ion is stable in these solvents. Similar superoxide ion chemistry has previously been demonstrated in volatile and environmentally suspect aprotic solvents such as dimethyl formamide and acetonitrile. However, ionic liquids are nonvolatile and should minimize the problems of secondary solvent waste. It is proposed that the resultant superoxide ion can be used to perform low temperature oxidation of wastes. Low-temperature oxidation of waste solvents can provide a much needed alternative to high-temperature waste incinerators, …

Municipal Waste Characteristics And Management In Pantai Dalam, Kuala Lumpur, Ratanam Andythaven

Student Works (2000-2009)

The primary purpose of this research was to study comprehensively the municipal waste generation (rate, quantity), waste characterization including (physical, chemical and biological parameters), heavy metal content, waste recovery and recycling, and socio economic aspects of municipal solid waste (MSW) generation and management in Taman Bukit Angkasa, Pantai Dalam, Kuala Lumpur and the surrounding areas. The waste characterization and management was determined with actual field observations coupled with questionnaire survey from a random sample of 250 households (200 flats houses, 25 long houses and 25 squatter residences). The quantification and other parameters (heavy metals, water extractable nutrients, nitrogen, pH, acidity, …

Municipal Wastewater Treatment Using Sequencing Batch Reactor (Sbr) Under Tropical Conditions, Maria Violetta Thomas

Student Works (2000-2009)

In this research project a Sequencing Batch Reactor (SBR) plant was tested for performance in terms of Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and Suspended Solids (SS), under different temporal conditions. In addition, the removal of biological nutrients, namely ammoniacal nitrogen, nitrate nitrogen and phosphorous in the form of phosphate, from the sewage, with anaerobic and aerobic operations using SBR was studied. The performance of the SBR plant was observed under two operating conditions whereby the variable studied was the total cycle time of the SBR process; i.e. 8-hour cycle mode and 6-hour cycle mode. The effluent quality …

Electrodeposition Of Niw Alloys Into Deep Recesses, Lakshmikanth Namburi

LSU Master's Theses

Pulse electrodeposition has been investigated as a general technique for the electrodeposition of nickel-tungsten alloys in deep recesses for MEMS. Ni-W exhibits an induced codeposition mechanism, where the Ni reaction rate enhances the codeposition of W. Electrodeposition of this alloy has been achieved into recesses of 500 micron deep. The challenges that have been encountered are those related to gas evolving side reactions, local pH rises, diffusional limitations of the soluble species and long times required for filling the recesses. Electrodeposition on cylinder electrodes at different rotation rates was also carried out in order to obtain data on composition of …

A Case Study Of The Beneficial Reuse Of Treated Groundwater, Andrew Curtis Elmore, Thomas Graff

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The future disposal of treated groundwater at the former Nebraska Ordnance Plant (NOP) Superfund site has been a topic of interest to the local property owners, the U.S. Army Corps of Engineers, and the local regulatory agencies. The Record of Decision for the site includes the extraction, treatment, and disposal of almost 3,000 gpm of groundwater with an estimated restoration time period exceeding 100 years. Interest from property owners and the Nebraska agency charged with regulating groundwater supply prompted the Corps of Engineers to consider several strategies for beneficially reusing the treated water. Alternatives included the establishment of a rural …

Purification And Characterization Of Crystallins By Aqueous Two-Phase Extraction, Ondrea Bermudez, Daniel Forciniti

Chemical and Biochemical Engineering Faculty Research & Creative Works

Crystallins are a family of water-soluble proteins that constitute up to 90% of the water-soluble proteins in mammalian eye lenses. We present in this paper an alternative purification method for these proteins using polyethylene glycol/dextran aqueous two-phase extraction. Under the appropriate conditions, we were able to recover the γ-crystallin fraction essentially free of the remaining proteins. High concentrations of salt at a neutral pH maximize the recovery of γ-crystallins in the top phase and minimize the contamination by the other proteins present in the lenses. The proposed protocol decreases the separation time by about 50%. The complex partition behavior observed …

Auditing And Biological Treatment Of Oleochemical Industry Waste, Fauziah Shahul Hamid

Student Works (2000-2009)

The utilization of renewable resources particularly from plant-based industries, such as, in the oleochemical sector makes it possible for further expansion of down-stream process products. However, to remain competitive the pollution generated from this industry should not be taken lightly. Implementation of cleaner technology into the oleochemical process will increase the efficiency of resource utilization of the industry, concurrently reducing quantity of waste generated. Waste audit conducted at Cognis Oleochemical (M) (COM) Sdn. Bhd. indicated that the major process-wastes generated by the facility were glycerol residue (GR) from Cognis Rika (M) Sdn. Bhd. (CRM) and wastewater sludge (WWS) from COM …

Preparation And Characterization Of Lithiated Cathode Materials For Lithium Batteries, Shanti Navaratnam

Student Works (2000-2009)

Four different cathode materials, LiNiO₂, LiCoO₂, LiCo₀.₂ Ni₀.₈O₂ and LiCo₀.₄, Ni₀.₆O₂ were synthesized by sol - gel technique. The prepared materials were characterized X-ray diffraction pattern, FT-IR and cyclic voltammetry. X-ray diffraction pattern shows crystallinity of materials, increases with higher calcination temperature. From FT- IR studies, it was shown, that the purity of sample also increased with prolong heating at higher temperatures. It was possible to obtain pure and highly crystalline LiNiO₂ after heating for fourteen hours at 800°c. Cyclic voltammetry shows the four prepared materials are suitable for fabrication of cathode, as lithium ions can intercalate and de-intercalate. LiNiO₂ …