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Articles 541 - 570 of 691

Full-Text Articles in Biochemical and Biomolecular Engineering

Two-Phase Flow Distribution In 2d Trickle-Bed Reactors, Y. Jiang, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic Jul 1999

Two-Phase Flow Distribution In 2d Trickle-Bed Reactors, Y. Jiang, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic

Chemical and Biochemical Engineering Faculty Research & Creative Works

An Extended Discrete Cell Model (DCM), based on Minimization of Energy Dissipation Rate, is Applied to Predict Two-Phase Flow Distribution in the Two-Dimensional Trickle-Bed Reactors. the Main Advantages of DCM Are that It Can Qualitatively Capture the Experimental Observations, and Readily Distinguish between Flow Distribution in Prewetted and Non-Prewetted Beds, as Well as Reflect the Effects of Bed Structure and Inlet Liquid Distributor on Two Phase Flow Distribution. for Comparison Purpose, the Results of Liquid Distribution Obtained by DCM Are Compared with Both Computational Fluid Dynamics (CFD) Simulations and Experimental Observations in a 2D Bed. the Achieved Qualitative and Quantitative …

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Comparative Hydrodynamics Study In A Bubble Column Using Computer-Automated Radioactive Particle Tracking (Carpt)/Computed Tomography (Ct) And Particle Image Velocimetry (Piv), Jinwen Chen, Abdenour Kemoun, Muthanna H. Al-Dahhan, Milorad P. Duduković, D. J. Lee, Liang Shih Fan Jul 1999

Comparative Hydrodynamics Study In A Bubble Column Using Computer-Automated Radioactive Particle Tracking (Carpt)/Computed Tomography (Ct) And Particle Image Velocimetry (Piv), Jinwen Chen, Abdenour Kemoun, Muthanna H. Al-Dahhan, Milorad P. Duduković, D. J. Lee, Liang Shih Fan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Hydrodynamics of a 10-Cm-Diameter Cylindrical Bubble Column at the Superficial Gas Velocity of 2, 4, and 8 Cm/s Are Investigated by Computer-Automated Radioactive Particle Tracking (CARPT), Particle Image Velocimetry (PIV), and Computed Tomography (CT). These Experimental Techniques Are Capable of Providing the Knowledge of Velocity and Holdup Fields in a Bubble Column System, Which Are Essential as the Experimental Benchmark for Modeling of Such Systems. the Flow Field of Liquid Phase, as Well as the Reynolds Stresses, Obtained by CARPT and PIV in an Air-Water System Are Compared in Detail. the Results Indicate that CARPT and PIV Complement Each …

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Parametric Study Of Unsteady-State Flow Modulation In Trickle-Bed Reactors, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Duduković Jul 1999

Parametric Study Of Unsteady-State Flow Modulation In Trickle-Bed Reactors, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Duduković

Chemical and Biochemical Engineering Faculty Research & Creative Works

Unsteady-State Liquid Flow Modulation (Periodic Operation) Was Investigated for Hydrogenation of Alpha-Methylstyrene to Cumene in a Hexane Solvent over 0.5% Pd on Alumina Spheres. This Test Reaction Was Run under Both Gas and Liquid Reactant-Limited Conditions. It is Shown that Periodic Liquid Flow Modulation Can Alter the Supply of Liquid and Gaseous Reactants to the Catalyst and Result in Reactor Performance Different from that Obtained under Steady-State Conditions. the Effect of Key Parameters Such as Extent of Gas/liquid Limitation, Total Cycle Period, Cycle Split, and Liquid Mass Velocity Were Investigated Experimentally to Demonstrate the Cause-Effect Relationships in Periodic Operation. Performance …

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Liquid Holdup Measurement Techniques In Laboratory High Pressure Trickle Bed Reactors, Muthanna H. Al-Dahhan, Wes Highfill Jan 1999

Liquid Holdup Measurement Techniques In Laboratory High Pressure Trickle Bed Reactors, Muthanna H. Al-Dahhan, Wes Highfill

Chemical and Biochemical Engineering Faculty Research & Creative Works

Three Different Techniques, Which Are Tracer, Drainage and Weighing Methods, Are Used to Measure Liquid Holdup in a Laboratory Trickle-Bed Reactor Operated under High Pressure. the Holdup Measurements Are Compared to Determine the Applicability of These Methods at High Pressure Operation. It Was Found that Tracer and Drainage Techniques Give Comparable Values for the Total Liquid Holdup. Although Several Investigators Recommended the Weighing Method over the Others based on their Experiments Performed at Atmospheric Conditions, It Was Found that the Weighing Method Failed to Measure Liquid Holdup Properly at High Pressure Operation.

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Frontal Chromatography Of Proteins: The Effect On Column Performance Of The Restricted Diffusion Of Molecules In Porous Chromatographic Adsorbents, Athanasios I. Liapis, H. Sadikoglu, Orrin K. Crosser Dec 1998

Frontal Chromatography Of Proteins: The Effect On Column Performance Of The Restricted Diffusion Of Molecules In Porous Chromatographic Adsorbents, Athanasios I. Liapis, H. Sadikoglu, Orrin K. Crosser

Chemical and Biochemical Engineering Faculty Research & Creative Works

A theoretical formulation is presented that can be used to describe the dynamic behavior of frontal chromatography of proteins in columns packed with adsorbent particles in which restricted pore diffusion of the adsorbate molecules occurs. The results of this work clearly indicate that the time for breakthrough and the effective utilization of the adsorptive capacity of the chromatographic particles increase as (a) the size of the adsorbate and/or ligand (active site) molecule decreases, (b) the pore connectivity, n(T), of the porous network of the adsorbent particles increases, and (c) the column length, L, increases. Copyright (C) 1998 Elsevier Science B.V.

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Network Modeling Of The Intraparticle Convection And Diffusion Of Molecules In Porous Particles Packed In A Chromatographic Column, J. J. Meyers, Athanasios I. Liapis Dec 1998

Network Modeling Of The Intraparticle Convection And Diffusion Of Molecules In Porous Particles Packed In A Chromatographic Column, J. J. Meyers, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A pore network model (cubic lattice network) is constructed to represent the porous structure in a column packed with porous chromatographic particles. Expressions are developed and used to determine, through the utilization of the pore network model, the intraparticle interstitial fluid velocity and pore diffusivity of a solute as the pore connectivity, n(T), of the porous medium is varied from 2.6 to 6.0. The results show that the intraparticle interstitial velocity and the pore diffusivity increase significantly as the value of the pore connectivity, n(T), increases, and clearly indicate that the pore connectivity, n(T), plays a key role in determining …

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Study On The Estimation And Control Of A Liquid Composite Molding Process, Dennis Sourlas, Susmito Naha, Gary Patterson, Richard Parnas Dec 1998

Study On The Estimation And Control Of A Liquid Composite Molding Process, Dennis Sourlas, Susmito Naha, Gary Patterson, Richard Parnas

Chemical and Biochemical Engineering Faculty Research & Creative Works

An on-line nonlinear receding horizon control algortithm is employed in order to achieve setpoint tracking targets in the context of liquid composite molding processes. The robustness of this control strategy against process-model deviations is tested. Finally, recursive parameter estimation is employed as a means of actively enhancing the performance of the process control algorithm. © 1998 AACC.

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Frontal Chromatography Of Proteins. Effect Of Axial Dispersion On Column Performance, G. A. Heeter, Athanasios I. Liapis Feb 1998

Frontal Chromatography Of Proteins. Effect Of Axial Dispersion On Column Performance, G. A. Heeter, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A mathematical model describing the dynamic adsorption of proteins in columns packed with spherical porous adsorbent particles is used to study the effect of axial dispersion on the performance of chromatographic systems. The values of the axial dispersion coefficient, D(L), are estimated from a correlation based on a model describing axial dispersion in packed beds that provides satisfactory results when compared with experiment. Simulations of frontal chromatography in systems including axial dispersion and in systems without axial dispersion are made and compared to determine the effect of axial dispersion on the efficiency of the adsorption process; also, the system parameters …

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Investigation Of A Complex Reaction Network: I. Experiments In A High-Pressure Trickle-Bed Reactor, M. R. Khadilkar, Y. Jiang, M. (Muthanna) H. Al-Dahhan, M. P. Duduković, S. K. Chou, G. Ahmed, R. Kahney Jan 1998

Investigation Of A Complex Reaction Network: I. Experiments In A High-Pressure Trickle-Bed Reactor, M. R. Khadilkar, Y. Jiang, M. (Muthanna) H. Al-Dahhan, M. P. Duduković, S. K. Chou, G. Ahmed, R. Kahney

Chemical and Biochemical Engineering Faculty Research & Creative Works

A High-Pressure Trickle-Bed Reactor Was Used to Achieve High Productivity and Selectivity for the Manufacture of a Key Herbicide Intermediate (Α-Aminomethyl-2-Furanmethanol (Amino Alcohol, AA) from Α-Nitromethyl-2-Furanmethanol (Nitro Alcohol, NA). Raney Nickel Catalysts of Varying Activity Were Prescreened for Suitability in Trickle-Bed Operation. the Effect of Operating Parameters Such as Reactant Feed Concentration, Liquid Mass Velocity, and Temperature on the Yield of Amino Alcohol (AA) for RNi-A Are Discussed. the Superiority of Trickle-Bed Reactors over Others Such as Semibatch and Batch Slurry Systems is Demonstrated. the AA Yield Increases with Decrease in Feed Reactant Concentration and Liquid Mass Velocity, as Well …

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Modeling Partially Premixed Fast Chemical Reactions In Statistically Homogeneous Turbulent Flow Using One-Dimensional Equations Of Change, Yang Gi Kim, X. B. Reed Jan 1998

Modeling Partially Premixed Fast Chemical Reactions In Statistically Homogeneous Turbulent Flow Using One-Dimensional Equations Of Change, Yang Gi Kim, X. B. Reed

Chemical and Biochemical Engineering Faculty Research & Creative Works

A pseudospectral algorithm has been used to compute solutions u(x,t), Ax,t), B(x,t), and R(x,t) to one-dimensional equations of change incorporating the simple reaction A + B → R for statistically homogeneous random velocity and partially premixed reactant concentration fields. An initial turbulence Reynolds number of 400 has been used, together with Damkohler numbers of 102 and 103 for fast reactions and Schmidt numbers of 10-3, 1, and 102 to span a wide range of diffusivities. Evolving concentration profiles inform intuition in general and provide insight into the evolution of the single-point statistical measures in particular: (A), (B), (a2), (b2), (ab), …

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Experimental Measurements And Simulation Of Mixing And Chemical Reaction In A Stirred Tank, Robertp Zipp, Gary Kent Patterson Jan 1998

Experimental Measurements And Simulation Of Mixing And Chemical Reaction In A Stirred Tank, Robertp Zipp, Gary Kent Patterson

Chemical and Biochemical Engineering Faculty Research & Creative Works

Effects of mixing on the rate of second-order chemical reactions have been studied by measuring the time-average degree of conversion at enough points in a steady-state, continuous-flow stirred reactor to provide comparisons with numerical simulations of the same reactions using a standard Reynolds-averaged turbulence simulation code with an added closure. The reactants were introduced in widely separated feed streams in order to provide a difficult test for the measurements and simulations. Concentration and segregation measurements were made with two fluorescence based methods - one remote and one using a fiber optic probe. The rates of mixing and reaction were simulated …

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Investigation Of A Complex Reaction Network: Ii. Kinetics, Mechanism And Parameter Estimation, Y. Jiang, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Duduković, S. K. Chou, G. Ahmed, R. Kahney Jan 1998

Investigation Of A Complex Reaction Network: Ii. Kinetics, Mechanism And Parameter Estimation, Y. Jiang, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Duduković, S. K. Chou, G. Ahmed, R. Kahney

Chemical and Biochemical Engineering Faculty Research & Creative Works

Conventional Strategies for Discrimination of Intrinsic and Apparent Kinetics from Crushed- and Whole-Catalyst-Pellet Experimental Data, Respectively, Do Not Yield Satisfactory Results for the Reaction Network in the Manufacture of Α-Aminomethyl-2-Furanmethanol (Aminoalcohol) from Α-Nitromethyl-2-Furanmethanol (Nitroalcohol). Laboratory Trickle-Bed Reactor Tests in the Range of Concentration and Product Yield of Commercial Interest Are Utilized to Yield a Reasonable Set of Kinetic Parameters, Which Are Otherwise Unobtainable. This is Accomplished by Proposing a Reaction Network, a Plausible Mechanism, and Optimizing the Kinetic Parameters based on the Reactor-Model-Generated Performance Data to Fit Experimental Output Concentrations of All Species for the Entire Set of Experiments. a …

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Prediction Of Pressure Drop And Liquid Holdup In High-Pressure Trickle-Bed Reactors, M. (Muthanna) H. Al-Dahhan, M. R. Khadilkar, Y. Wu, M. P. Duduković Jan 1998

Prediction Of Pressure Drop And Liquid Holdup In High-Pressure Trickle-Bed Reactors, M. (Muthanna) H. Al-Dahhan, M. R. Khadilkar, Y. Wu, M. P. Duduković

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Holub Et Al. (1992, 1993) Phenomenological Model for Pressure Drop and Liquid Holdup in Trickle Flow Regime at Atmospheric Pressure Was Noted by Al-Dahhan and Duduković (1994) to Systematically Underpredict Pressure Drop at High Pressure and High Gas Flow Rates. in This Study, the Holub Et Al. (1992, 1993) Model Has Been Extended to Account for the Interaction between the Gas and Liquid Phases by Incorporating the Velocity and the Shear Slip Factors between the Phases. as a Result, the Prediction of Pressure Drop at the Operating Conditions of Industrial Interest (High Pressure) Has Been Improved Noticeably Without Any …

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An Empirical Relation Between The Mark-Houwink-Sakurada Constants, P. Rai, Stephen L. Rosen Sep 1997

An Empirical Relation Between The Mark-Houwink-Sakurada Constants, P. Rai, Stephen L. Rosen

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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Model Discrimination And Estimation Of The Intraparticle Mass Transfer Parameters For The Adsorption Of Bovine Serum Albumin Onto Porous Adsorbent Particles By The Use Of Experimental Frontal Analysis Data, G. A. Heeter, Athanasios I. Liapis Jul 1997

Model Discrimination And Estimation Of The Intraparticle Mass Transfer Parameters For The Adsorption Of Bovine Serum Albumin Onto Porous Adsorbent Particles By The Use Of Experimental Frontal Analysis Data, G. A. Heeter, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

Experimental data from a chromatographic system involving the adsorption of bovine serum albumin (BSA) onto porous anion-exchange adsorbent particles packed in a column are presented. The parameters that characterize the mass transfer mechanisms of intraparticle diffusion and convection are estimated by fitting the predictions of dynamic mathematical models describing adsorption in column systems having spherical perfusive and purely diffusive adsorbent Particles to the experimental breakthrough data obtained from the column adsorption system. Both linear and nonlinear expressions for the equilibrium isotherm are considered. The values of the transport parameters are estimated in the time domain for the nonlinear adsorption models …

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Accumulation Of Lead By Anabaena Cylindrica: Mathematical Modeling And An Energy Dispersive X-Ray Study, David T. Swift, Daniel Forciniti Jul 1997

Accumulation Of Lead By Anabaena Cylindrica: Mathematical Modeling And An Energy Dispersive X-Ray Study, David T. Swift, Daniel Forciniti

Chemical and Biochemical Engineering Faculty Research & Creative Works

The ability of microorganisms to selectively adsorb various heavy metal ions has been recognized for over a decade. We have investigated the biosorption of lead by an active culture of the cyanobacterium Anabaena cylindrica. Energy dispersive X-ray microanalysis was used to evaluate the different uptake mechanisms in the various subcellular regions. Three were identified; a very fast adsorption mechanism in the cell envelope; a time- dependent deposition reaction on the cell surface; and an adsorption mechanism, also time dependent, on the polyphosphate body inside the cell. Atomic absorption spectrometry was then used to quantify the changes with time of bulk …

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Estimation Of Pore Diameter For Intraparticle Fluid Flow In Hidisperse Porous Chromatographic Particles, G. A. Heeter, Athanasios I. Liapis Feb 1997

Estimation Of Pore Diameter For Intraparticle Fluid Flow In Hidisperse Porous Chromatographic Particles, G. A. Heeter, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A quantitative method is developed and presented for estimating the mean pore diameter, d(pore), that could allow intraparticle fluid flow in the macroporous region of adsorbent particles with a bidisperse porous structure packed in a column. The method is used to estimate the value of d(pore) that is required to obtain specified values of the fraction, F, of the column superficial fluid velocity that is flowing through the macroporous region of the adsorbent particles and the value of d(pore) that is required to obtain specified values of the intraparticle Peclet number, Pe(intra).

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Affinity Adsorption Of Adsorbates Into Spherical Monodisperse And Bidisperse Porous Perfusive And Purely Diffusive Adsorbent Particles Packed In A Column. Parameter Estimation In The Laplace Transform Domain, G. A. Heeter, Athanasios I. Liapis Jan 1997

Affinity Adsorption Of Adsorbates Into Spherical Monodisperse And Bidisperse Porous Perfusive And Purely Diffusive Adsorbent Particles Packed In A Column. Parameter Estimation In The Laplace Transform Domain, G. A. Heeter, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A novel mathematical method for parameter estimation is proposed and used to estimate in the Laplace transform domain the values of the parameters that characterize the mechanisms of intraparticle diffusion and convection in spherical perfusive or purely diffusive adsorbent particles with a monodisperse or with a bidisperse porous structure when the adsorbent particles are packed in a column. The parameter estimation method in the Laplace transform domain presented in this work is significantly simpler, easier to use and dramatically faster than the conventional parameter estimation procedure in the time domain, which requires the repeated numerical solution of the partial differential …

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Tomographic And Particle Tracking Studies In A Liquid-Solid Riser, Shantanu Roy, Jinwen Chen, Sailesh B. Kumar, M. (Muthanna) H. Al-Dahhan, M. P. Duduković Jan 1997

Tomographic And Particle Tracking Studies In A Liquid-Solid Riser, Shantanu Roy, Jinwen Chen, Sailesh B. Kumar, M. (Muthanna) H. Al-Dahhan, M. P. Duduković

Chemical and Biochemical Engineering Faculty Research & Creative Works

A Liquid-Solid Circulating Fluidized Bed is a Potential Reactor of Interest in a Variety of Industrial Processes, Such as Petroleum Refining, and in the Synthesis of Fine Chemicals, Petrochemicals, and Foodstuffs. Rapid Deactivation of the Solid Catalyst in These Processes Necessitates Regeneration and Regulation of the Solids into the Riser Section in Which the Principal Reaction is Accomplished. in This Study We Show that Computer-Automated Radioactive Particle Tracking (CARPT) Can Be Used to Obtain Solids Velocity Patterns in the Riser and that Backflow of Solids Exists at the Tested Liquid Velocities. Γ-Ray Computed Tomography (CT) Reveals Slightly Higher Solids Concentrations …

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Assessment Of The Effects Of High-Pressure Operation On The Liquid-Solid Mass-Transfer Coefficient In Trickle-Bed Reactors, M. (Muthanna) H. Al-Dahhan, W. Highfill, M. Friedman Jan 1997

Assessment Of The Effects Of High-Pressure Operation On The Liquid-Solid Mass-Transfer Coefficient In Trickle-Bed Reactors, M. (Muthanna) H. Al-Dahhan, W. Highfill, M. Friedman

Chemical and Biochemical Engineering Faculty Research & Creative Works

Trickle-Bed Reactors Are Used Widely in Industry and Are Usually Operated at High Pressure. All the Studies on Liquid-Solid Mass Transfer in Such Reactors Were Performed under Atmospheric Pressure And, Hence, the Empirical Correlations for Liquid-Solid Mass-Transfer Coefficients (K1s and K1sa) Were Developed based on Atmospheric Data. However, These Correlations Incorporate One or More of the Parameters Affected by Pressure (E.g., Liquid Holdup, Catalyst Wetting Efficiency, Pressure Drop, Gas Density). in This Work the Effects of High Pressure and High Gas Flow Rates on the Predicted Coefficients using Some of These Correlations Are Evaluated. It is Shown that There Are …

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High-Pressure Trickle-Bed Reactors: A Review, Muthanna H. Al-Dahhan, Faical Larachi, Milorad P. Dudukovic, Andre Laurent Jan 1997

High-Pressure Trickle-Bed Reactors: A Review, Muthanna H. Al-Dahhan, Faical Larachi, Milorad P. Dudukovic, Andre Laurent

Chemical and Biochemical Engineering Faculty Research & Creative Works

A Concise Review of Relevant Experimental Observations and Modeling of High-Pressure Trickle-Bed Reactors, based on Recent Studies, is Presented. the Following Topics Are Considered: Flow Regime Transitions, Pressure Drop, Liquid Holdup, Gas-Liquid Interfacial Area and Mass-Transfer Coefficient, Catalyst Wetting Efficiency, Catalyst Dilution with Inert Fines, and Evaluation of Trickle-Bed Models for Liquid-Limited and Gas-Limited Reactions. the Effects of High-Pressure Operation, Which is of Industrial Relevance, on the Physicochemical and Fluid Dynamic Parameters Are Discussed. Empirical and Theoretical Models Developed to Account for the Effect of High Pressure on the Various Parameters and Phenomena Pertinent to the Topics Discussed Are Briefly …

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Limitations And Dynamics Imposed On Multicomponent Batch Distillation By Tray Hydraulics, Keith G. Tomazi Jan 1997

Limitations And Dynamics Imposed On Multicomponent Batch Distillation By Tray Hydraulics, Keith G. Tomazi

Chemical and Biochemical Engineering Faculty Research & Creative Works

Batch distillation models incorporating a complete set of hydraulic relations, energy balances, and tray efficiencies and simpler models based upon constant molar holdup and zero holdup (the Rayleigh equation) were used to obtain distillation curves and optimal reflux policies. The approach to hydraulic limitations was monitored in the complete hydraulic model. The results indicate that during a multicomponent batch distillation the combination of the changes in the liquid composition and liquid flow rates causes the molar holdup on the trays to vary with time and, consequently, the characteristic time constant of the trays changes. The predicted composition profiles for descriptions …

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A Small-Angle Neutron Scattering Study Of Γ-Crystallins Near Their Isoelectric Point, Paul Petitt, Michael Eugene Edwards, Daniel Forciniti Jan 1997

A Small-Angle Neutron Scattering Study Of Γ-Crystallins Near Their Isoelectric Point, Paul Petitt, Michael Eugene Edwards, Daniel Forciniti

Chemical and Biochemical Engineering Faculty Research & Creative Works

In this paper, a small-angle neutron scattering study of γII-crystallins near their isoelectric point is presented. The experiments were carried out using protein concentrations of 5.7-85.7 mg/ml at temperatures in the range 11-60°C. The experimental data were analyzed using an ellipsoidal model for intraparticle correlations and the mean spherical approximation for interparticle correlations. Our studies revealed that γII-crystallins have a thick hydration layer, which is possibly due to the special arrangement of polar and ionic groups on their surface. The temperature scan shows that, as a result of relatively strong attractive forces, clusters of two, three, or higher oligomers are …

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Effects Of Structural And Kinetic Parameters On The Performance Of Chromatographic Columns Packed With Perfusive And Purely Diffusive Adsorbent Particles, G. A. Heeter, Athanasios I. Liapis Aug 1996

Effects Of Structural And Kinetic Parameters On The Performance Of Chromatographic Columns Packed With Perfusive And Purely Diffusive Adsorbent Particles, G. A. Heeter, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A mathematical model describing dynamic adsorption in columns with spherical bidisperse perfusive or spherical bidisperse purely diffusive adsorbent particles is used to study the effects of the structural parameters of the adsorbent particles and of the parameters of the adsorption mechanism on the performance of chromatographic systems involving the adsorption of bovine serum albumin onto anion-exchange porous adsorbent particles. Four structural parameters are studied: the particle diameter, d(p), the macropore void fraction, ε(p), the microparticle diameter, d(m) and the parameter φ which affects the value of the permeability of the adsorbent particle. Two parameters of the adsorption mechanism are studied: …

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Multi-Component Perfusion Chromatography In Fixed Bed And Periodic Counter Current Column Operation, G. A. Heeter, Athanasios I. Liapis May 1996

Multi-Component Perfusion Chromatography In Fixed Bed And Periodic Counter Current Column Operation, G. A. Heeter, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A mathematical model of multi-component dynamic adsorption in columns with spherical perfusive and spherical purely diffusive adsorbent particles with a bidisperse porous structure is constructed, solved, and used to study the performance of a binary adsorption system in a single-column fixed-bed process and in a two-column periodic countercurrent process in which the adsorbent is equally distributed over two beds. The total length of the two-column periodic counter-current system is equal to the length of the single-column fixed-bed system. The performance of fixed-bed and periodic counter-current systems with both perfusive and purely diffusive adsorbent particles is examined for different values of …

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Modelling And Analysis Of The Elution Stage Of "Perfusion Chromatography" Effects Of Intraparticle Convective Velocity And Microsphere Size On System Performance, Y. Xu, Athanasios I. Liapis Feb 1996

Modelling And Analysis Of The Elution Stage Of "Perfusion Chromatography" Effects Of Intraparticle Convective Velocity And Microsphere Size On System Performance, Y. Xu, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A mathematical model describing the dynamic elution (elution stage) in columns with spherical bidisperse perfusive or spherical bidisperse purely diffusive adsorbent particles is presented and its solution is obtained numerically. The desorption of bovine serum albumin (BSA) from spherical anion-exchange porous particles was studied for different values of the intraparticle Peclet numbers of the adsorbate, (Peintra)a, and eluent, (Peintra)e, and of the microsphere diameter, dm. It was found that as (Peintra)a increases, the asymmetry of the elution peak of the adsorbate (at the exit of the column) decreases, the peak height increases and the time, Te, required for the elution …

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A Lattice Boltzmann Subgrid Model For High Reynolds Number Flows, S. Hou, James D. Sterling, S. Chen, G. D. Doolen Jan 1996

A Lattice Boltzmann Subgrid Model For High Reynolds Number Flows, S. Hou, James D. Sterling, S. Chen, G. D. Doolen

Business and Information Technology Faculty Research & Creative Works

A sub grid turbulence model for the lattice Boltzmann method is proposed for high Reynolds number fluid flow applications. The method, based on the standard Smagorinsky sub grid model and a single-time relaxation lattice Boltzmann method, incorporates the advantages of the lattice Boltzmann method for handling arbitrary boundaries and is easily implemented on parallel machines. The method is applied to a two-dimensional driven cavity flow for studying dynamics and the Reynolds number dependence of the flow structures. The substitution of other sub grid models, such as the dynamic sub grid model, in the framework of the LB method is discussed.

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Modified Contactor For Experimental Studies Of Mass Transfer And Chemical Reaction Across A Liquid-Liquid Interface, Muthanna H. Al-Dahhan, Charles E. Wicks Jan 1996

Modified Contactor For Experimental Studies Of Mass Transfer And Chemical Reaction Across A Liquid-Liquid Interface, Muthanna H. Al-Dahhan, Charles E. Wicks

Chemical and Biochemical Engineering Faculty Research & Creative Works

A Modified Stirred-Cell Type Contactor Has Been Designed and Tested for its Use in Experimental Investigations of Mass Transfer and Chemical Reaction in Liquid-Liquid Systems. its Design overcomes the Shortcomings of Previously Proposed Contactors. It is Easy to Operate and Has the Ability to Investigate the Effect of a Wide Range of Operating Conditions. the Mixing Performance of the Contactor Was Tested using a Dye Injection and a Tracer Technique. Experiments to Evaluate Mass-Transfer Coefficients Across a Liquid-Liquid Interface Have Been Conducted to Determine its Effectiveness. the Results Verified that the Contactor Could Be Successfully Employed as a Useful Experimental …

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Evaluation Of Trickle Bed Reactor Models For A Liquid Limited Reaction, Yuanxin Wu, Muthanna H. Al-Dahhan, Mohan R. Khadilkar, Milorad P. Dudukovic Jan 1996

Evaluation Of Trickle Bed Reactor Models For A Liquid Limited Reaction, Yuanxin Wu, Muthanna H. Al-Dahhan, Mohan R. Khadilkar, Milorad P. Dudukovic

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Isothermal Decomposition of Hydrogen Peroxide on a CuCr Catalyst in a Laboratory Scale Trickle Bed Reactor Was Used to Test Model Predictions of the Dependence of Liquid Reactant Conversion on Space Time for Different Operating Conditions. It is Assured that the Decomposition of Hydrogen Peroxide is a First Order Liquid-Limited Reaction. Comparison of Model Predictions and Experimental Data Indicates that Both External Mass Transfer Effects and Incomplete External Catalyst Wetting Need to Be Accounted For. Dudukovic's (1977) Approximate Model for the Catalyst Effectiveness Factor Adequately Simulates Both Effects.

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Comparison Of Trickle-Bed And Upflow Reactor Performance At High Pressure: Model Predictions And Experimental Observations, M. R. Khadilkar, Y. X. Wu, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic, M. Colakyan Jan 1996

Comparison Of Trickle-Bed And Upflow Reactor Performance At High Pressure: Model Predictions And Experimental Observations, M. R. Khadilkar, Y. X. Wu, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic, M. Colakyan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Comparison of Laboratory Trickle-Bed and Up-Flow Reactors over a Range of Operating Conditions, Which Cover Both Gas and Liquid Reactant Limitations, Has Been Investigated using Hydrogenation of Alpha-Methylstyrene to Cumene in a Hexane Solvent over 2.5% Pd on Alumina Extrudate Catalyst as a Test Reaction. the Results Show that When the Reaction is Gas Limited at Low Pressure and High Liquid Feed Concentration, Trickle Bed Reactor Outperforms the Upflow Reactor. at High Pressure and Low Liquid Feed Concentration, the Reaction Becomes Liquid Limited and Upflow Reactor Performs Better. It is Concluded that the Advantage of Upflow or Downflow Depends on …

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