The Experts below are selected from a list of 12 Experts worldwide ranked by ideXlab platform

Narayana R Aluru - One of the best experts on this subject based on the ideXlab platform.

  • Combined circuit/device modeling and simulation of integrated microfluidic systems
    Journal of Microelectromechanical Systems, 2005
    Co-Authors: Arindam Chatterjee, Narayana R Aluru
    Abstract:

    A combined circuit/device model for the analysis of integrated microfluidic systems is presented. The complete model of an integrated microfluidic device incorporates modeling of fluidic transport, Chemical Reaction, Reagent mixing, and separation. The fluidic flow is generated by an applied electrical field or by a combined electrical field and pressure gradient. In the proposed circuit/device model, the fluidic network has been represented by a circuit model and the functional units of the /spl mu/-TAS (micro Total Analysis System) have been represented by appropriate device models. We demonstrate the integration of the circuit and the device models by using an example, where the output from the fluidic transport module serves as the input for the other modules such as mixing, Chemical Reaction and separation. The combined circuit/device model can be used for analysis and design of entire microfluidic systems with very little computational expense, while maintaining the desired level of accuracy.

  • Circuit modeling and simulation of integrated microfluidic systems
    2004
    Co-Authors: Aveek N. Chatterjee, Narayana R Aluru
    Abstract:

    A combined circuit-device model for the analysis of integrated microfluidic system is presented. The complete model of an integrated microfluidic device incorporates modeling of the fluidic transport, Chemical Reaction, Reagent mixing and separation. The microfluidic flow can be caused by an applied electrical potential gradient and/or a pressure gradient. In the proposed compact model, the fluidic network has been modeled by a circuit based representation and the other modules of theP-TAS have been represented by a device model. As an example, we present the modeling and simulation of a lab-on-a-chip.

Gillis Johannes Dekorte - One of the best experts on this subject based on the ideXlab platform.

  • The influence of CO? on the steam gasification rate of a typical South African coal
    2013
    Co-Authors: Du Toit, Gillis Johannes Dekorte
    Abstract:

    iii Abstract It is recognised that the Reactions with steam and CO2 are the rate limiting step during coal gasification, and a vast number of studies has been dedicated to the kinetics of these Reactions. Most studies were carried out by using a single reactant (CO2 or H2O), either pure or diluted with an inert gas. Research using gas mixtures of CO2 and steam and their effects on gasification kinetics have been undertaken but are limited. The objective of this study is to determine the effects of CO2 on the steam gasification rate of a typical Highveld seam 4 coal. The South African medium ranked high volatile bituminous coal was charred at 950 °C. 2.0 g samples of ± 1 mm particles were analysed in a modified large particle thermo gravimetric analyser under various reactant gas concentrations. Experiments were conducted at atmospheric pressure (87.5 kPa) and temperatures from 775 to 900 °C, such that the conversion rate was controlled by Chemical Reaction. Reagent mixtures of steam-N2, steamCO2 and CO2-N2 at concentrations of 25-75 mol%, 50-50 mol%, 75-25 mol% and 100 mol% were investigated. Arrhenius plots for steam and CO2 gasification produced activation energy values of 225 ± 23 kJ/mol and 243 ± 32 kJ/mol respectively. The calculated Reaction orders with respect to Reagent partial pressure were 0.44 ± 0.08 and 0.56 ± 0.07 for steam and CO2 respectively. Comparisons of the experimental data showed a higher Reaction rate for the steam-CO2 mixtures compared to steam-N2 experiments. The semi empirical Wen model (m = 0.85) with an additive Langmuir-Hinshelwood styled rate equation predicted the mixed Reagent gasification accurately. Reaction constants that were determined from the pure reactant experiments could directly be applied to predict the results for the experiments with mixtures of steam and CO2. The conclusion was made that under the investigated conditions steam and CO2 reacts simultaneously on different active sites on the char surface.

  • the influence of co on the steam gasification rate of a typical south african coal
    2013
    Co-Authors: Du Toit, Gillis Johannes Dekorte
    Abstract:

    iii Abstract It is recognised that the Reactions with steam and CO2 are the rate limiting step during coal gasification, and a vast number of studies has been dedicated to the kinetics of these Reactions. Most studies were carried out by using a single reactant (CO2 or H2O), either pure or diluted with an inert gas. Research using gas mixtures of CO2 and steam and their effects on gasification kinetics have been undertaken but are limited. The objective of this study is to determine the effects of CO2 on the steam gasification rate of a typical Highveld seam 4 coal. The South African medium ranked high volatile bituminous coal was charred at 950 °C. 2.0 g samples of ± 1 mm particles were analysed in a modified large particle thermo gravimetric analyser under various reactant gas concentrations. Experiments were conducted at atmospheric pressure (87.5 kPa) and temperatures from 775 to 900 °C, such that the conversion rate was controlled by Chemical Reaction. Reagent mixtures of steam-N2, steamCO2 and CO2-N2 at concentrations of 25-75 mol%, 50-50 mol%, 75-25 mol% and 100 mol% were investigated. Arrhenius plots for steam and CO2 gasification produced activation energy values of 225 ± 23 kJ/mol and 243 ± 32 kJ/mol respectively. The calculated Reaction orders with respect to Reagent partial pressure were 0.44 ± 0.08 and 0.56 ± 0.07 for steam and CO2 respectively. Comparisons of the experimental data showed a higher Reaction rate for the steam-CO2 mixtures compared to steam-N2 experiments. The semi empirical Wen model (m = 0.85) with an additive Langmuir-Hinshelwood styled rate equation predicted the mixed Reagent gasification accurately. Reaction constants that were determined from the pure reactant experiments could directly be applied to predict the results for the experiments with mixtures of steam and CO2. The conclusion was made that under the investigated conditions steam and CO2 reacts simultaneously on different active sites on the char surface.

Du Toit - One of the best experts on this subject based on the ideXlab platform.

  • The influence of CO? on the steam gasification rate of a typical South African coal
    2013
    Co-Authors: Du Toit, Gillis Johannes Dekorte
    Abstract:

    iii Abstract It is recognised that the Reactions with steam and CO2 are the rate limiting step during coal gasification, and a vast number of studies has been dedicated to the kinetics of these Reactions. Most studies were carried out by using a single reactant (CO2 or H2O), either pure or diluted with an inert gas. Research using gas mixtures of CO2 and steam and their effects on gasification kinetics have been undertaken but are limited. The objective of this study is to determine the effects of CO2 on the steam gasification rate of a typical Highveld seam 4 coal. The South African medium ranked high volatile bituminous coal was charred at 950 °C. 2.0 g samples of ± 1 mm particles were analysed in a modified large particle thermo gravimetric analyser under various reactant gas concentrations. Experiments were conducted at atmospheric pressure (87.5 kPa) and temperatures from 775 to 900 °C, such that the conversion rate was controlled by Chemical Reaction. Reagent mixtures of steam-N2, steamCO2 and CO2-N2 at concentrations of 25-75 mol%, 50-50 mol%, 75-25 mol% and 100 mol% were investigated. Arrhenius plots for steam and CO2 gasification produced activation energy values of 225 ± 23 kJ/mol and 243 ± 32 kJ/mol respectively. The calculated Reaction orders with respect to Reagent partial pressure were 0.44 ± 0.08 and 0.56 ± 0.07 for steam and CO2 respectively. Comparisons of the experimental data showed a higher Reaction rate for the steam-CO2 mixtures compared to steam-N2 experiments. The semi empirical Wen model (m = 0.85) with an additive Langmuir-Hinshelwood styled rate equation predicted the mixed Reagent gasification accurately. Reaction constants that were determined from the pure reactant experiments could directly be applied to predict the results for the experiments with mixtures of steam and CO2. The conclusion was made that under the investigated conditions steam and CO2 reacts simultaneously on different active sites on the char surface.

  • the influence of co on the steam gasification rate of a typical south african coal
    2013
    Co-Authors: Du Toit, Gillis Johannes Dekorte
    Abstract:

    iii Abstract It is recognised that the Reactions with steam and CO2 are the rate limiting step during coal gasification, and a vast number of studies has been dedicated to the kinetics of these Reactions. Most studies were carried out by using a single reactant (CO2 or H2O), either pure or diluted with an inert gas. Research using gas mixtures of CO2 and steam and their effects on gasification kinetics have been undertaken but are limited. The objective of this study is to determine the effects of CO2 on the steam gasification rate of a typical Highveld seam 4 coal. The South African medium ranked high volatile bituminous coal was charred at 950 °C. 2.0 g samples of ± 1 mm particles were analysed in a modified large particle thermo gravimetric analyser under various reactant gas concentrations. Experiments were conducted at atmospheric pressure (87.5 kPa) and temperatures from 775 to 900 °C, such that the conversion rate was controlled by Chemical Reaction. Reagent mixtures of steam-N2, steamCO2 and CO2-N2 at concentrations of 25-75 mol%, 50-50 mol%, 75-25 mol% and 100 mol% were investigated. Arrhenius plots for steam and CO2 gasification produced activation energy values of 225 ± 23 kJ/mol and 243 ± 32 kJ/mol respectively. The calculated Reaction orders with respect to Reagent partial pressure were 0.44 ± 0.08 and 0.56 ± 0.07 for steam and CO2 respectively. Comparisons of the experimental data showed a higher Reaction rate for the steam-CO2 mixtures compared to steam-N2 experiments. The semi empirical Wen model (m = 0.85) with an additive Langmuir-Hinshelwood styled rate equation predicted the mixed Reagent gasification accurately. Reaction constants that were determined from the pure reactant experiments could directly be applied to predict the results for the experiments with mixtures of steam and CO2. The conclusion was made that under the investigated conditions steam and CO2 reacts simultaneously on different active sites on the char surface.

Aveek N. Chatterjee - One of the best experts on this subject based on the ideXlab platform.

  • Circuit modeling and simulation of integrated microfluidic systems
    2004
    Co-Authors: Aveek N. Chatterjee, Narayana R Aluru
    Abstract:

    A combined circuit-device model for the analysis of integrated microfluidic system is presented. The complete model of an integrated microfluidic device incorporates modeling of the fluidic transport, Chemical Reaction, Reagent mixing and separation. The microfluidic flow can be caused by an applied electrical potential gradient and/or a pressure gradient. In the proposed compact model, the fluidic network has been modeled by a circuit based representation and the other modules of theP-TAS have been represented by a device model. As an example, we present the modeling and simulation of a lab-on-a-chip.

Arindam Chatterjee - One of the best experts on this subject based on the ideXlab platform.

  • Combined circuit/device modeling and simulation of integrated microfluidic systems
    Journal of Microelectromechanical Systems, 2005
    Co-Authors: Arindam Chatterjee, Narayana R Aluru
    Abstract:

    A combined circuit/device model for the analysis of integrated microfluidic systems is presented. The complete model of an integrated microfluidic device incorporates modeling of fluidic transport, Chemical Reaction, Reagent mixing, and separation. The fluidic flow is generated by an applied electrical field or by a combined electrical field and pressure gradient. In the proposed circuit/device model, the fluidic network has been represented by a circuit model and the functional units of the /spl mu/-TAS (micro Total Analysis System) have been represented by appropriate device models. We demonstrate the integration of the circuit and the device models by using an example, where the output from the fluidic transport module serves as the input for the other modules such as mixing, Chemical Reaction and separation. The combined circuit/device model can be used for analysis and design of entire microfluidic systems with very little computational expense, while maintaining the desired level of accuracy.