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Missouri University of Science and Technology

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Articles 451 - 480 of 691

Full-Text Articles in Biochemical and Biomolecular Engineering

Phase Distribution In An Upflow Monolith Reactor Using Computed Tomography, M. (Muthanna) H. Al-Dahhan, A. Kemoun, A. R. Cartolano Feb 2006

Phase Distribution In An Upflow Monolith Reactor Using Computed Tomography, M. (Muthanna) H. Al-Dahhan, A. Kemoun, A. R. Cartolano

Chemical and Biochemical Engineering Faculty Research & Creative Works

Computed Tomography (CT) is Known to Be a Viable Technique for Determining Flow Maldistribution in Two-Phase Flow through Packed Beds. in This Study, Gamma Ray Computed Tomography Has Been Used to Quantify the Flow Distribution in a Monolith Catalytic Bed, with Water as the Liquid Phase and Air as the Gas Phase, Flowing Co-Currently Upward. the Flow Conditions Were Selected to Bracket Some Commercially Viable Operating Conditions for Such Reactors. in the Monolith Core Region, Fairly Uniform Flow Distribution Has Been Obtained for All the Flow Conditions Used. This Distribution is Quantified using the Standard Deviation of the Holdup Distribution. …

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Nanoparticles For Enhanced Delivery Of Chemotherapeutics, Emily J. Bahram-Ahi Jan 2006

Nanoparticles For Enhanced Delivery Of Chemotherapeutics, Emily J. Bahram-Ahi

Opportunities for Undergraduate Research Experience Program (OURE)

Delivery of the anticancer drug paclitaxel (commercially known as Taxol®) is difficult due to its limited solubility in aqueous media. This study proposes a novel bubble bursting technique to generate nanoparticles of the chemotherapeutic in an effort to decrease potential side effects and improve the bioavailability of hydrophobic drugs. The bubble bursting apparatus will be used to produce nanoparticles of a biodegradable polymer, poly(lactide-co-glycolide) (PLGA), as carriers for paclitaxel. The dissolved paclitaxel in this biodegradable polymer matrix will be released at a controlled rate for a more efficient delivery of the drug throughout the body.

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Experimental Study Of The Solids Velocity Field In Gas-Solid Risers, Satish Bhusarapu, Muthanna H. Al-Dahhan, Milorad P. Duduković, Steven Trujillo, Timothy J. O'Hern Dec 2005

Experimental Study Of The Solids Velocity Field In Gas-Solid Risers, Satish Bhusarapu, Muthanna H. Al-Dahhan, Milorad P. Duduković, Steven Trujillo, Timothy J. O'Hern

Chemical and Biochemical Engineering Faculty Research & Creative Works

Solids Flow Dynamics in Gas-Solid Risers is Inherently Complex. Model Refinement through Experimental Validation Requires the Acquisition of Detailed Nonintrusive Measurements. in This Study, Noninvasive Computer-Automated Radioactive Particle Tracking (CARPT) is Employed to Visualize and Quantify in a Three-Dimensional Domain the Solids Dynamics and Mixing in Gas-Solid Risers. This Technique Has the Added Advantage that, along with the Derived Eulerian Solids Flow Field (Time-Average Velocity Map and Various Turbulence Parameters Such as the Reynolds Stresses, Turbulent Kinetic Energy), It Also Provides Directly the Lagrangian Description of the Solids Motion. the Solids Velocity Field Data Are Obtained in Two Different Risers …

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Solids Flow Mapping In A High Pressure Slurry Bubble Column, Novica Rados, Ashfaq Shaikh, Muthanna H. Al-Dahhan Nov 2005

Solids Flow Mapping In A High Pressure Slurry Bubble Column, Novica Rados, Ashfaq Shaikh, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Successful Design and Scale-Up of Slurry Bubble Column Reactors (SBCRs) Require Proper Understanding of How Operating Conditions Affect their Flow Behavior. Presently, there is Little Information on the Flow Dynamics of Solids (E.g., Distribution of Velocities and Turbulent Parameters) in Slurry Systems that Are Operated at Industrially Relevant Conditions of High Pressure, High Superficial Gas Velocities, and High Solids Loading. Computer Automated Radio Particle Tracking (CARPT) is Widely Recognized as One of a Few Techniques that Can Be Reliably Used Even in Highly Turbulent and Opaque Slurry Flows. This Work Utilizes an Improved CARPT Technique to Investigate the Effect of …

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Polymer-Mediated Synthesis Of Highly Dispersed Pt Nanoparticles On Carbon Black, Min Chen, Yangchuan Xing Sep 2005

Polymer-Mediated Synthesis Of Highly Dispersed Pt Nanoparticles On Carbon Black, Min Chen, Yangchuan Xing

Chemical and Biochemical Engineering Faculty Research & Creative Works

A new method was developed to prepare highly dispersed Pt nanoparticles on carbon black to use as proton exchange membrane (PEM) fuel cell catalysts. This method involves using a polymer, poly-(vinylpyrrolidone) (PVP), to prevent particle aggregation and thereby reduce nanoparticle sizes to achieve high dispersion. It was found that Pt nanoparticles mediated by PVP are smaller than those obtained without PVP and have a narrower size distribution. Well-dispersed Pt nanoparticles with metal loadings from 5 to 35 wt % were obtained on carbon black (Vulcan XC-72R). It was found that well-dispersed Pt nanoparticles on carbon black could be synthesized at …

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The Processing, Mechanical Properties And Bioactivity Of Zinc Based Glass Ionomer Cements, D. Boyd, Mark R. Towler Sep 2005

The Processing, Mechanical Properties And Bioactivity Of Zinc Based Glass Ionomer Cements, D. Boyd, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

The suitability of Glass Ionomer Cements (GICs) for use in orthopaedics is retarded by the presence in the glass phase of aluminium, a neurotoxin. Unfortunately, the aluminium ion plays an integral role in the setting process of a GIC and its absence is likely to hinder cement formation. However, zinc oxide, a bacteriocide, can act both as a network modifying oxide and an intermediate oxide in a similar fashion to alumina and so ternary systems based on zinc silicates often have extensive regions of glass formation. The purpose of this research was to produce novel GICs based on calcium zinc …

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Modeling Catalytic Trickle-Bed And Upflow Packed-Bed Reactors For Wet Air Oxidation Of Phenol With Phase Change, Jing Guo, Muthanna H. Al-Dahhan Aug 2005

Modeling Catalytic Trickle-Bed And Upflow Packed-Bed Reactors For Wet Air Oxidation Of Phenol With Phase Change, Jing Guo, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

In This Study, to Simulate the Steady-State Behavior of Packed-Bed Reactors for Catalytic Wet Oxidation of Phenol, One-Dimensional (1D) Axial Dispersion Model for the Liquid Phase is Coupled with a Cell Stack Model for the Gas Phase, Providing Considerable Phase Change under the Selected Operating Conditions. the Reactor Scale Governing Equations, Reaction Kinetics Involved, and Solution Strategy Are Discussed. the Computational Approach Accounts for the Observed Catalyst Activities, Combined with Local Transport and Catalyst Wetting Effects. the Approach Selected is Shown to Be Suitable and Efficient in Dealing with the Problem in Question. Comparisons of Simulated Model Predictions and Lab …

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Flow Distribution Characteristics Of A Gas-Liquid Monolith Reactor, Shaibal Roy, Muthanna H. Al-Dahhan Aug 2005

Flow Distribution Characteristics Of A Gas-Liquid Monolith Reactor, Shaibal Roy, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Flow Distribution Characteristics in a 0.05 M Diameter Monolith Reactor, Operated Co-Current Downward in the Taylor Flow Regime, Was Investigated and Quantified using Gamma Ray Computed Tomography (CT). the Results Indicate that the Flow Distribution is a Strong Function of Liquid Distributor Design, and Gas and Liquid Superficial Velocities. Additionally, within the Range of Gas and Liquid Superficial Velocities Investigated, a Window of Operating Condition (Gas and Liquid Velocities) Was Identified Which Resulted in a Close to Uniform Phase Distribution. © 2005 Elsevier B.V. All Rights Reserved.

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Dynamic Modeling Of Slurry Bubble Column Reactors, Novica Rados, Muthanna H. Al-Dahhan, Milorad P. Duduković Aug 2005

Dynamic Modeling Of Slurry Bubble Column Reactors, Novica Rados, Muthanna H. Al-Dahhan, Milorad P. Duduković

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Multicomponent, One-Dimensional, and Compartment-Based Dynamic Model Developed by Rados Et Al. (Catal. Today 2003, 79-80, 211-218) Has Been Used to Study the Performance of Slurry Bubble Columns Operated with Two Chemical Reaction Systems. One Reaction Causes Contraction in the Gas-Phase Volume, and the Other Causes Expansion. the Change in the Gas Flow Rate (Expansion or Contraction) Along the Reactor as a Result of the Chemical Reaction Kinetics is Accounted for by the overall Mass Balance of the Gas Phase Represented by Large and Small Bubbles. the Importance of Properly Accounting for the Change in the Gas Flow Rate Has …

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Multicomponent Flow-Transport-Reaction Modeling Of Trickle Bed Reactors: Application To Unsteady State Liquid Flow Modulation, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Duduković Aug 2005

Multicomponent Flow-Transport-Reaction Modeling Of Trickle Bed Reactors: Application To Unsteady State Liquid Flow Modulation, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Duduković

Chemical and Biochemical Engineering Faculty Research & Creative Works

A One-Dimensional Reactor and Catalyst Pellet Scale Flow-Transport-Reaction Model Utilizing the Multicomponent Stefan-Maxwell Formulation for Inter- and Intraphase Transport is Developed to Simulate Unsteady State Operation in Trickle Bed Reactors. the Governing Equations and Method of Solution Are Discussed. Results Are Presented for a Model Reaction System (Hydrogenation of A-Methylstyrene) under Gas Reactant Limiting Conditions, for Liquid Flow Modulation as a Test Case of Unsteady State Operation. Model Simulations Predict that Periodic Liquid Flow Modulation Can Alter the Supply of Liquid and Gaseous Reactants to the Catalyst and Result in Reactor Performance Enhancement above that Achieved in Steady State Operation. …

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Multiphase Flow Packed-Bed Reactor Modeling: Combining Cfd And Cell Network Model, Yi Jiang, Jing Guo, Muthanna H. Al-Dahhan Jul 2005

Multiphase Flow Packed-Bed Reactor Modeling: Combining Cfd And Cell Network Model, Yi Jiang, Jing Guo, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Performance of a Multiphase Flow Packed-Bed Reactor Was Evaluated by a Mixing-Cell Network Model in Which the Cell-Scale Flow Field Information Was Provided by Multifluid CFD Modeling. Such a Sequentially Combined Modeling Approach Was Able to Show the Heterogeneity of Liquid Species Conversion in a Trickle-Bed Reactor that Has Been Confirmed by in Situ Magnetic Resonance Experiments. 1 a Conventional Plug Flow Model (PFM) and Axial Dispersion Model (ADM) Showed Either overpredicted or Underpredicted Conversion Compared with the Conversion Computed from the CFD-Cell Network Model. Preliminary Case Study Has Shown the Ability of the CFD-Cell Network Model in Assessing …

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Modeling And Scale-Up Of Mixing- And Temperature-Sensitive Chemical Reactions, Gary Patterson Jul 2005

Modeling And Scale-Up Of Mixing- And Temperature-Sensitive Chemical Reactions, Gary Patterson

Chemical and Biochemical Engineering Faculty Research & Creative Works

A review of published measurements of yield for complex chemical reactions in mixed reactors of various types and methods of modeling and simulating such reactions for the purpose of reactor scale-up shows the extent of progress that has been made. Reaction kinetics for very fast competitive reactions are usually difficult and expensive to determine. Many reaction processes must be scaled up from bench- and/or pilot-scale experiments that produce yield data under various mixing conditions. the variables that strongly affect the yield results are the reaction types and their rates, feed point in the reactor, feed injection velocity and scale, mixing …

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Liquid Saturation And Gas-Liquid Distribution In Multiphase Monolithic Reactors, Tobias Bauer, Shaibal Roy, Ruediger Lange, Muthanna H. Al-Dahhan Jun 2005

Liquid Saturation And Gas-Liquid Distribution In Multiphase Monolithic Reactors, Tobias Bauer, Shaibal Roy, Ruediger Lange, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Monolith Bed is One of the Promising Catalytic Reactors for a Number of Chemical Gas-Liquid-Solid Processes. in the Present Work, Liquid Saturations for Five Different Monoliths Have Been Investigated Experimentally in a Cold-Flow Unit with a Reactor Diameter of 5.0 Cm. the Influences of Gas and Liquid Flow Rates and of the Direction of Two-Phase Flow on Liquid Saturation Were Examined. the Results Indicate that the Direction of Flow Has No Significant Influence on Liquid Saturation for Proper Gas-Liquid Distribution. the Experimental Results Are in Good Agreement with Predictions of the Drift Flux Model using the Distribution Parameter Proposed …

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Flow Pattern Visualization In A Mimic Anaerobic Digester Using Cfd, Mehul S. Vesvikar, Muthanna H. Al-Dahhan Mar 2005

Flow Pattern Visualization In A Mimic Anaerobic Digester Using Cfd, Mehul S. Vesvikar, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Three-Dimensional Steady-State Computational Fluid Dynamics (CFD) Simulations Were Performed in Mimic Anaerobic Digesters to Visualize their Flow Pattern and Obtain Hydrodynamic Parameters. the Mixing in the Digester Was Provided by Sparging Gas at Three Different Flow Rates. the Gas Phase Was Simulated with Air and the Liquid Phase with Water. the CFD Results Were First Evaluated using Experimental Data Obtained by Computer Automated Radioactive Particle Tracking (CARPT). the Simulation Results in Terms of overall Flow Pattern, Location of Circulation Cells and Stagnant Regions, Trends of Liquid Velocity Profiles, and Volume of Dead Zones Agree Reasonably Well with the Experimental Data. …

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Experimental Investigation Of The Hydrodynamics In A Liquid-Solid Riser, Shantanu Roy, Abdenour Kemoun, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic Mar 2005

Experimental Investigation Of The Hydrodynamics In A Liquid-Solid Riser, Shantanu Roy, Abdenour Kemoun, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic

Chemical and Biochemical Engineering Faculty Research & Creative Works

Liquid-Solid Fluid Dynamics Has Been Investigated in a 6-In. (0.15 M) "Cold-Flow" Circulating Fluidized Bed Riser using Non-Invasive Flow Monitoring Methods. Gamma-Ray Computed Tomography (CT) Was Used to Measure the Time-Averaged Cross-Sectional Solids Volume Fraction Distributions at Several Elevations. the Time-Averaged Mean and "Fluctuating" Solids Velocity Fields Were Quantified using the Computer-Automated Radioactive Particle Tracking (CARPT) Technique. the Experimental Equipment, Protocol of Implementation, and Data Analysis Have Been Discussed Briefly, with Particular Emphasis on the Specific Features in the Use of These Techniques for Studying High-Density Turbulent Flows as in a Liquid-Solid Riser. the Experimental Study Examines Nine Operating Conditions, …

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Catalytic Wet Air Oxidation Of Phenol In Concurrent Downflow And Upflow Packed-Bed Reactors Over Pillared Clay Catalyst, Jing Guo, Muthanna H. Al-Dahhan Feb 2005

Catalytic Wet Air Oxidation Of Phenol In Concurrent Downflow And Upflow Packed-Bed Reactors Over Pillared Clay Catalyst, Jing Guo, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

An Experimental Study is Presented for Comparing the Behavior of a Packed Bed Reactor in the Catalytic Liquid-Phase Oxidation of Aqueous Phenol with Two Modes of Operation, Downflow and Upflow. the Operating Parameters Investigated Included Temperature, Reactor Pressure, Gas Flowrate, Liquid Hourly Space Velocity and Feed Concentration. Because of the Completely Wetted Catalyst, the Upflow Reactor Generally Performs Better for High Pressures and Low Feed Concentrations When the Liquid Reactant Limitation Controls the Rate. the Interaction between the Reactor Hydrodynamics, Mass Transfer, and Reaction Kinetics is Discussed. for Both Operation Modes, Complete Phenol Removal and Significant Total Organic Carbon (TOC) …

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Physico-Chemical Characteristics Of European Pulverized Coal Combustion Fly Ashes, N. Moreno, X. Querol, J. M. Andrés, K. Stanton, Mark R. Towler, H. Nugteren, M. Janssen-Jurkovicová, R. Jones Jan 2005

Physico-Chemical Characteristics Of European Pulverized Coal Combustion Fly Ashes, N. Moreno, X. Querol, J. M. Andrés, K. Stanton, Mark R. Towler, H. Nugteren, M. Janssen-Jurkovicová, R. Jones

Chemical and Biochemical Engineering Faculty Research & Creative Works

Fly ashes sourced from European pulverized coal burning power plants (from Spain, The Netherlands, Italy and Greece) were characterized in terms of their chemical composition, mineralogy and physical properties. The amount and composition of the glass present in the ashes were also determined. The materials analyzed have very different compositions and were selected with a view to determining their suitability for different applications and for further studies on applications. The results were compared to the literature to determine their similarities to UK coal fly ashes. Chemical analysis has enabled the categorization of the ashes based on their oxide contents. Devitrification …

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Flow Distribution Characteristics Of A Gas-Liquid Monolith Reactor Using Computed Tomography, Shaibal Roy, Muthanna H. Al-Dahhan Jan 2005

Flow Distribution Characteristics Of A Gas-Liquid Monolith Reactor Using Computed Tomography, Shaibal Roy, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Flow Distribution Characteristics Were Investigated and Quantified in a 0.05 M Diameter Monolith Reactor, Operated Co-Current Downward in the Taylor Flow Regime, using Gamma Ray Computed Tomography (CT). the Flow Conditions Were Selected to Operate the Reactor in the Taylor Flow Regime and to Bracket Some Commercially Viable Operating Conditions for Such Reactors. Various Operating Parameters Were Evaluated for their Effect on the Degree of Flow Non-Uniformity in the Monolith Crosssection. the Results Show that within the Range of Gas and Liquid Superficial Velocities Investigated, There Exists a Window of Operating Conditions (Intermediate Gas and Liquid Velocities) Which Corresponds to …

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Phase Distribution In A High Pressure Slurry Bubble Column Via A Single Source Computed Tomography, Novica Rados, Ashfaq Shaikh, Muthanna H. Al-Dahhan Jan 2005

Phase Distribution In A High Pressure Slurry Bubble Column Via A Single Source Computed Tomography, Novica Rados, Ashfaq Shaikh, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Due to their Numerous Advantages, Slurry Bubble Column Reactors (SBCR) Are Gaining Wide Importance in the Petroleum, Petrochemical, Chemical, and Biochemical Industries. Most Previous Literature Studies on the Fluid Dynamics and the Phase Holdup Distribution in SBCR Are Limited to Low Superficial Gas Velocity, Low Solids Loading, and the Atmospheric Pressure. Moreover, the Presence of a Solids Phase Poses Difficulties in Probe Measurement Techniques Such as Pitot Tube and Optical Probe and See through Measurement Techniques Such as Particle Image Velocimetry (PIV), Laser Doppler Velocimetry (LDV). Single Source Γ-Ray Computed Tomography (CT) Has Been Used to Measure Cross-Sectional Phase Holdup …

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Monoliths As Multiphase Reactors: A Review, Shaibal Roy, Tobias Bauer, Muthanna H. Al-Dahhan, Peter Lehner, Thomas Turek Nov 2004

Monoliths As Multiphase Reactors: A Review, Shaibal Roy, Tobias Bauer, Muthanna H. Al-Dahhan, Peter Lehner, Thomas Turek

Chemical and Biochemical Engineering Faculty Research & Creative Works

Monolith Reactors Are Being Studied as a Replacement for Conventional Multiphase Reactors Such as Trickle-Bed Reactors, Slurry Reactors, and Slurry Bubble Column Reactors for Gas-Liquid-Solid Reactions. Reactors with Monolith Catalyst Packing Have Been Found to Be Hydrodynamically Superior to Existing Industrial Reactors. This Review Covers Multiphase Reactions Carried Out in Monolith Reactors by Various Researchers. It First Defines the Monolith Reactor and Looks into the Geometrical Aspects of Monolith. the Section Dealing with Hydrodynamics Reviews Pressure Drop, Phase Holdup, Flow Distribution, and Dispersion Characteristics. This Study Also Considers the Tools Used to Characterize the Hydrodynamic Parameters and their Typical Values. …

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Quantification Of Solids Flow In A Gas-Solid Riser: Single Radioactive Particle Tracking, Satish Bhusarapu, Muthanna H. Al-Dahhan, Milorad P. Dudukovic Nov 2004

Quantification Of Solids Flow In A Gas-Solid Riser: Single Radioactive Particle Tracking, Satish Bhusarapu, Muthanna H. Al-Dahhan, Milorad P. Dudukovic

Chemical and Biochemical Engineering Faculty Research & Creative Works

Solids in Risers of Circulating Fluidized Beds (CFB) Exhibit Local Backflow and Recirculation. Measurement of the Concentration-Time Response to an Impulse Injection of Tracer, Even at Two Elevations Cannot Determine the Residence Time Distribution (RTD) of Solids Uniquely. Hence, Evaluation of RTD in Risers from Conventional Tracer Responses is Difficult and Often Not Possible. in Addition, Estimating the Solids Circulation Rate in These Closed Loop Systems, is a Non-Trivial Problem. in This Work, a Single Radioactive Particle in the CFB Loop is Tracked during its Multiple Visits to the Riser And, by Invoking Ergodicity, Solids Circulation Rate, Accurate Solids RTD …

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Liquid Holdup And Pressure Drop In The Gas-Liquid Cocurrent Downflow Packed-Bed Reactor Under Elevated Pressures, Jing Guo, Muthanna H. Al-Dahhan Nov 2004

Liquid Holdup And Pressure Drop In The Gas-Liquid Cocurrent Downflow Packed-Bed Reactor Under Elevated Pressures, Jing Guo, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

An Experimental Investigation of the Residence Time Distribution, Liquid Holdup, and Pressure Drop in a Gas-Liquid Downflow Packed Bed Reactor with Porous Particles Operated under Elevated Pressures is Presented. the Effects of the Two-Phase Flow Rates and Reactor Pressures on the External Liquid Holdup and Pressure Drop Are Discussed. a Mechanistic Model, Which Accounts for the Interaction between the Gas and Liquid Phases by Incorporating the Shear and Velocity Slip Factors between Phases, is Employed to Predict the External Liquid Holdup and Pressure Drop for the Experimentally Covered Flow Regime. the Involved Parameters, Such as Shear and Velocity Slip Factors …

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Optimization Of Batch Reactions In Series With Uncertainty, Keith G. Tomazi Nov 2004

Optimization Of Batch Reactions In Series With Uncertainty, Keith G. Tomazi

Chemical and Biochemical Engineering Faculty Research & Creative Works

Certain types of chemical reactions, such as the global deprotection of a polypeptide, are extremely complex. As a result, it may be very difficult or expensive to develop accurate models of these chemical reactions. Without a satisfactory kinetic model for the reaction, it is difficult to develop an optimum operating policy that will maximize the profit. Stochastic optimization is applied in this work to an example process step to obtain the optimum reaction temperature and reaction time. In the case of the "here and now" problem, the optimal conditions are a lower reaction temperature and a longer reaction time than …

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Determining Suitability Of A Fly Ash For Silica Extraction And Zeolite Synthesis, Natàlia Moreno, Xavier Querol, Angel López-Soler, José Manuel Andres, Maria Janssen, Henk Nugteren, Mark R. Towler, Kenneth Stanton Sep 2004

Determining Suitability Of A Fly Ash For Silica Extraction And Zeolite Synthesis, Natàlia Moreno, Xavier Querol, Angel López-Soler, José Manuel Andres, Maria Janssen, Henk Nugteren, Mark R. Towler, Kenneth Stanton

Chemical and Biochemical Engineering Faculty Research & Creative Works

Zeolitic material is obtained from fly ash both by direct conversion of the ash or from SiO2 extracts obtained from fly ash. This study focuses on determining the suitability of a fly ash for SiO2 extraction and for zeolite synthesis by direct conversion. The SiO2 extraction experiments from different fly ashes show that the main parameters governing the SiO2 extraction are: (a) a high bulk SiO2 content (> 52%, for obtaining an extraction yield of 100 g SiO2 kg-1) in the starting fly ash, (b) a high proportion (> 55%) of the bulk SiO …

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Investigation Into The Ultrasonic Setting Of Glass Ionomer Cements : Part Ii Setting Times And Compressive Strengths, E. Twomey, Mark R. Towler, C. M. Crowley, J. Doyle, S. Hampshire Jul 2004

Investigation Into The Ultrasonic Setting Of Glass Ionomer Cements : Part Ii Setting Times And Compressive Strengths, E. Twomey, Mark R. Towler, C. M. Crowley, J. Doyle, S. Hampshire

Chemical and Biochemical Engineering Faculty Research & Creative Works

The ultrasonic setting of glass ionomer cements (GIC) was discussed. It was observed that the ultrasonic setting resulted in improvements of compressive strength. An increase in the PAA molecular weight from PAA50 to PAA200 resulted in an increase in the strength, but with a further increase in the PAA molecular weight to PAA450, there was a reduction in the strength. Results show that the strength of the ultrasonically set materials after 1 day were close to the values for the 7 days chemically set samples.

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The Influence Of Strontium Substitution In Fluorapatite Glasses And Glass-Ceramics, R. G. Hill, A. Stamboulis, R. V. Law, A. Clifford, Mark R. Towler, C. Crowley May 2004

The Influence Of Strontium Substitution In Fluorapatite Glasses And Glass-Ceramics, R. G. Hill, A. Stamboulis, R. V. Law, A. Clifford, Mark R. Towler, C. Crowley

Chemical and Biochemical Engineering Faculty Research & Creative Works

Strontium is often substituted for calcium in order to confer radio-opacity in glasses used for dental cements, Biocomposites and bio glass-ceramics. The present paper investigates the influence of substituting strontium for calcium in a glass of the following composition: 4.5SiO23Al2O 31.5P2O53CaO2CaF2, having a Ca:P ratio of 1.67 corresponding to calcium fluorapatite (Ca5(PO 4)3F). The glasses were characterized by magic angle spinning nuclear magnetic resonance (MAS-NMR), by differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD). The 29Si, 27Al and 31P NMR spectra for the glasses with …

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Characterisation Of The Glass Fraction Of A Selection Of European Coal Fly Ashes, J. Henry, Mark R. Towler, K. T. Stanton, X. Querol, N. Moreno May 2004

Characterisation Of The Glass Fraction Of A Selection Of European Coal Fly Ashes, J. Henry, Mark R. Towler, K. T. Stanton, X. Querol, N. Moreno

Chemical and Biochemical Engineering Faculty Research & Creative Works

Fly ash largely consists of the inorganic content of coal that remains after combustion. The crystalline phases present in fly ash may form upon cooling of a molten alumino-silicate glass. This view is supported by the spherical shape of many fly ash particles, inferring that they have gone through a viscous fluid state. The amorphous content in fly ash is believed to dominate reactivity behaviour, under both alkaline and acid conditions, because glasses have a higher potential energy than the equivalent crystal structure and the variation of bond angles and distances in a glass makes the bond breakage easier. It …

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A Sequential Approach To Modeling Catalytic Reactions In Packed-Bed Reactors, Jing Guo, Muthanna H. Al-Dahhan May 2004

A Sequential Approach To Modeling Catalytic Reactions In Packed-Bed Reactors, Jing Guo, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

A Sequential Modeling Approach is Proposed to Simulate Catalytic Reactions in Packed-Bed Reactors. the Hydrogenation of Alpha-Methylstyrene and Wet Oxidation of Phenol Are Selected as Studied Cases. the Modeling Scheme Combines a Reactor Scale Axial Dispersion Model with a Pellet Scale Model. Without Involving Any Fitting Parameters, Such an Approach Accounts for the Non-Linear Reaction Kinetics Expression and Different Types of Pellet-Liquid Wetting Contact. to Validate the Developed Modeling Scheme and the Parallel Approach Reported in the Literature, the Experimental Observations for Hydrogenation of Alpha-Methylstyrene to Cumene Have Been Employed. the Predicted Results by Both Approaches Agree Reasonably with the …

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Analyzing And Modeling Of Photobioreactors By Combining First Principles Of Physiology And Hydrodynamics, Hu Ping Luo, Muthanna H. Al-Dahhan Feb 2004

Analyzing And Modeling Of Photobioreactors By Combining First Principles Of Physiology And Hydrodynamics, Hu Ping Luo, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Mixing in Photobioreactors is Known to Enhance Biomass Productivity Considerably, and Flow Dynamics Play a Significant Role in the Reactor's Performance, as They Determine the Mixing and the Cells' Movement. in This Work We Focus on Analyzing the Effects of Mixing and Flow Dynamics on the Photobioreactor Performance. based on Hydrodynamic Findings from the CARPT(Computer Automated Radioactive Particle Tracking) Technique, a Possible Mechanism for the Interaction between the Mixing and the Physiology of Photosynthesis is Presented, and the Effects of Flow Dynamics on Light Availability and Light Intensity Fluctuation Are Discussed and Quantitatively Characterized. Furthermore, a Dynamic Modeling Approach is …

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Laboratory Automation Curriculum At Keck Graduate Institute, James D. Sterling Jan 2004

Laboratory Automation Curriculum At Keck Graduate Institute, James D. Sterling

Business and Information Technology Faculty Research & Creative Works

A novel curriculum in laboratory automation and high-throughput technologies has been developed at the Keck Graduate Institute (KGI) over the past five years as part of the professional master's degree program in applied life sciences. The goal of this curriculum has been four-fold: (1) motivate study by describing the need for automation through several example problems in combinatorial biological discovery, (2) provide elements of fundamental engineering science that are required for the development of the technologies and tools that enable automation, (3) provide opportunities for the students to see and use state-of-the-art instruments, learn about existing industry standards, and to …

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