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Paitoon Tontiwachwuthikul - One of the best experts on this subject based on the ideXlab platform.

  • co2 Absorption kinetics of 4 diethylamine 2 butanol solvent using stopped flow technique
    Separation and Purification Technology, 2014
    Co-Authors: Teerawat Sema, Paitoon Tontiwachwuthikul, Zhiwu Liang, Kaiyun Fu, Raphael Idem, Yanqing Na
    Abstract:

    Abstract In the present work, a stopped-flow apparatus was used to determine the CO 2 Absorption kinetics of 4-diethylamine-2-butanol (DEAB) in terms of observed pseudo-first-order Rate Constant ( k 0 ) and second order reaction Rate Constant ( k 2 ). The experiments were done using DEAB in the concentration range of 0.10–0.90 kmol/m 3 , and a temperature range of 293–313 K. The p K a of DEAB was also experimentally determined over a temperature range of 278–333 K. The Bronsted relationship between the reaction Rate Constant obtained from the stopped-flow apparatus and p K a obtained from experimental determination was then evaluated. The results showed that the Bronsted correlation could predict the Absorption Rate Constant with an AAD of 8.6%, which is within an acceptable range of 10%. By comparing through different evaluation techniques such as k 2 , p K a and Δ r G m ° , it was observed that DEAB has faster reaction kinetics than those of conventional tertiary amines, namely, DEMEA, DMMEA and MDEA.

  • kinetics of co2 Absorption into a novel 1 diethylamino 2 propanol solvent using stopped flow technique
    Aiche Journal, 2014
    Co-Authors: Zhiwu Liang, Teerawat Sema, Raphael Idem, Yanqing Na, Wichitpan Rongwong, Chen Li, Paitoon Tontiwachwuthikul
    Abstract:

    A stopped-flow apparatus was used to measure the kinetics of carbon dioxide (CO2) Absorption into aqueous solution of 1-diethylamino-2-propanol (1DEA2P) in terms of observed pseudo-first-order Rate Constant (ko) and second-order reaction Rate Constant (k2), in this work. The experiments were conducted over a 1DEA2P concentration range of 120–751 mol/m3, and a temperature range of 298–313 K. As 1DEA2P is a tertiary amine, the base-catalyzed hydration mechanism was, then, applied to correlate the experimental CO2 Absorption Rate Constants obtained from stopped-flow apparatus. In addition, the pKa of 1DEA2P was experimentally measured over a temperature range of 278–333 K. The Bronsted relationship between reaction Rate Constant (obtained from stopped-flow apparatus) and pKa was, then, studied. The results showed that the correlation based on the Bronsted relationship performed very well for predicting the Absorption Rate Constant with an absolute average deviation of 5.2%, which is in an acceptable range of less than 10%. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3502–3510, 2014

Raphael Idem - One of the best experts on this subject based on the ideXlab platform.

  • co2 Absorption kinetics of 4 diethylamine 2 butanol solvent using stopped flow technique
    Separation and Purification Technology, 2014
    Co-Authors: Teerawat Sema, Paitoon Tontiwachwuthikul, Zhiwu Liang, Kaiyun Fu, Raphael Idem, Yanqing Na
    Abstract:

    Abstract In the present work, a stopped-flow apparatus was used to determine the CO 2 Absorption kinetics of 4-diethylamine-2-butanol (DEAB) in terms of observed pseudo-first-order Rate Constant ( k 0 ) and second order reaction Rate Constant ( k 2 ). The experiments were done using DEAB in the concentration range of 0.10–0.90 kmol/m 3 , and a temperature range of 293–313 K. The p K a of DEAB was also experimentally determined over a temperature range of 278–333 K. The Bronsted relationship between the reaction Rate Constant obtained from the stopped-flow apparatus and p K a obtained from experimental determination was then evaluated. The results showed that the Bronsted correlation could predict the Absorption Rate Constant with an AAD of 8.6%, which is within an acceptable range of 10%. By comparing through different evaluation techniques such as k 2 , p K a and Δ r G m ° , it was observed that DEAB has faster reaction kinetics than those of conventional tertiary amines, namely, DEMEA, DMMEA and MDEA.

  • kinetics of co2 Absorption into a novel 1 diethylamino 2 propanol solvent using stopped flow technique
    Aiche Journal, 2014
    Co-Authors: Zhiwu Liang, Teerawat Sema, Raphael Idem, Yanqing Na, Wichitpan Rongwong, Chen Li, Paitoon Tontiwachwuthikul
    Abstract:

    A stopped-flow apparatus was used to measure the kinetics of carbon dioxide (CO2) Absorption into aqueous solution of 1-diethylamino-2-propanol (1DEA2P) in terms of observed pseudo-first-order Rate Constant (ko) and second-order reaction Rate Constant (k2), in this work. The experiments were conducted over a 1DEA2P concentration range of 120–751 mol/m3, and a temperature range of 298–313 K. As 1DEA2P is a tertiary amine, the base-catalyzed hydration mechanism was, then, applied to correlate the experimental CO2 Absorption Rate Constants obtained from stopped-flow apparatus. In addition, the pKa of 1DEA2P was experimentally measured over a temperature range of 278–333 K. The Bronsted relationship between reaction Rate Constant (obtained from stopped-flow apparatus) and pKa was, then, studied. The results showed that the correlation based on the Bronsted relationship performed very well for predicting the Absorption Rate Constant with an absolute average deviation of 5.2%, which is in an acceptable range of less than 10%. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3502–3510, 2014

S. Fukada - One of the best experts on this subject based on the ideXlab platform.

  • study on hydrogen Absorption in zr powder used for tritium confinement in a production system of tritium for fusion reactors with a high temperature gas cooled reactor
    Nuclear materials and energy, 2018
    Co-Authors: J. Izumino, K. Katayama, H. Matsuura, S. Fukada
    Abstract:

    ABSTRACT A tritium production method using a high-temperature gas-cooled reactor loaded with lithium compound particles has been proposed for steadily starting up and stably operating a fusion reactor. In order to confine the produced tritium, small lithium-compound particles are considered to be coated by ceramic materials. The present authors have proposed adding zirconium fine particles into the inside of the ceramic coating to improve tritium confinement performance. In this work, powdered zirconium was exposed to hydrogen or deuterium gas in a closed volume at elevated temperatures and Absorption Rate Constant and Sieverts' Constant were evaluated by the pressure drop by Absorption. After the experiments, it was found that the powdered zirconium sample became a lump by a sintering effect. By referring literature data for α-zirconium and its oxide, the observed Absorption Rate was speculated to include the influence of sintering and oxide layer. The obtained Sieverts’ Constants were slightly smaller than literature data. By taking into account the observed hydrogen Absorption behavior in powdered zirconium, tritium leak from alumina-coated lithium-compound particles containing zirconium fine particles was roughly estimated in some conditions. Tritium permeation Rate can be reduced by adding zirconium but the leak suppression effect is limited.

  • Study on hydrogen Absorption in Zr powder used for tritium confinement in a production system of tritium for fusion reactors with a high-temperature gas-cooled reactor
    Elsevier, 2018
    Co-Authors: J. Izumino, K. Katayama, H. Matsuura, S. Fukada
    Abstract:

    ABSTRACT: A tritium production method using a high-temperature gas-cooled reactor loaded with lithium compound particles has been proposed for steadily starting up and stably operating a fusion reactor. In order to confine the produced tritium, small lithium-compound particles are considered to be coated by ceramic materials. The present authors have proposed adding zirconium fine particles into the inside of the ceramic coating to improve tritium confinement performance. In this work, powdered zirconium was exposed to hydrogen or deuterium gas in a closed volume at elevated temperatures and Absorption Rate Constant and Sieverts' Constant were evaluated by the pressure drop by Absorption. After the experiments, it was found that the powdered zirconium sample became a lump by a sintering effect. By referring literature data for α-zirconium and its oxide, the observed Absorption Rate was speculated to include the influence of sintering and oxide layer. The obtained Sieverts’ Constants were slightly smaller than literature data. By taking into account the observed hydrogen Absorption behavior in powdered zirconium, tritium leak from alumina-coated lithium-compound particles containing zirconium fine particles was roughly estimated in some conditions. Tritium permeation Rate can be reduced by adding zirconium but the leak suppression effect is limited. Keywords: Hydrogen Absorption, Zirconium, Tritium confinemen

Gary M Pollack - One of the best experts on this subject based on the ideXlab platform.

  • a modified residual method to estimate the zero order Absorption Rate Constant in a one compartment model
    Biopharmaceutics & Drug Disposition, 1997
    Co-Authors: Xingrong Liu, Kim L. R. Brouwer, Gary M Pollack
    Abstract:

    The objective of this work was to develop a simple residual method to estimate the Rate Constant for actual or apparent zero-order Absorption into a one-compartment model. The method is based on the fact that, in theory, a plot of residuals versus e−Kt is linear for a zero-order Absorption process, where K represents the elimination Rate Constant governing the terminal phase of the concentration–time profile. The apparent Absorption Rate Constant (K0) can be calculated from the slope and intercept of the residual plot. Simulated concentration–time data with superimposed random error (CV=5, 10, 15%, n =8), as well as data sets from the literature for hydroflumethiazide and theophylline were analyzed with the proposed method of residuals. Parameters derived with the new technique were compared to both the nonlinear least-squares regression and the Wagner–Nelson method, all of which yield comparable K0 estimates. These results indicate that the proposed method of residuals represents a simple approach for estimating the apparent zero-order Absorption Rate Constant analogous to classic residual analysis for first-order Absorption. ©1997 by John Wiley & Sons, Ltd.

  • use of a pharmacokinetic model incorporating discontinuous gastrointestinal Absorption to examine the occurrence of double peaks in oral concentration time profiles
    Pharmaceutical Research, 1992
    Co-Authors: A B Suttle, Gary M Pollack, Kim L. R. Brouwer
    Abstract:

    Double peaks in the plasma concentration-time profile following oral administration have been reported for several compounds. A pharmacokinetic model incorporating discontinuous Absorption was developed to simulate concentration-time profiles with double peaks. The gastrointestinal (GI) tract was divided into N compartments, with Absorption occurring only from the second and Nth compartments. A two-compartment model was used to describe systemic drug disposition. The effect of gastric emptying and GI transit Rate Constants (Kl and K1, respectively), number of hypothetical gut compartments, and Absorption Rate Constant at each site (Ka1, Ka2) on the time of occurrence of each peak (Tp1, Tp2), the theoretical fraction of the dose absorbed at each site (phi 1, phi 2), and the contribution of the second site to systemic drug exposure (expressed as phi 2rel) were examined. Simulated concentration-time profiles demonstRated that Tp2 was determined by Kt and N, while Tp1 was determined by K1 and Kt. Changes in Ka1 and Ka2 had no effect on Tp1 or Tp2. phi 1, phi 2, and phi 2rel were determined by Ka1, Ka2, and Kt, and simulations indicated that a secondary peak in the concentration-time profile will be evident only when phi 2rel is substantial. In addition, concentration-time data for ranitidine and cimetidine, which displayed double peaks, were fit with the model. The present model described both data sets well, and realistic pharmacokinetic and physiologic parameters (Absorption Rate Constants, systemic bioavailabilities, GI residence times) were obtained.

Zhiwu Liang - One of the best experts on this subject based on the ideXlab platform.

  • co2 Absorption kinetics of 4 diethylamine 2 butanol solvent using stopped flow technique
    Separation and Purification Technology, 2014
    Co-Authors: Teerawat Sema, Paitoon Tontiwachwuthikul, Zhiwu Liang, Kaiyun Fu, Raphael Idem, Yanqing Na
    Abstract:

    Abstract In the present work, a stopped-flow apparatus was used to determine the CO 2 Absorption kinetics of 4-diethylamine-2-butanol (DEAB) in terms of observed pseudo-first-order Rate Constant ( k 0 ) and second order reaction Rate Constant ( k 2 ). The experiments were done using DEAB in the concentration range of 0.10–0.90 kmol/m 3 , and a temperature range of 293–313 K. The p K a of DEAB was also experimentally determined over a temperature range of 278–333 K. The Bronsted relationship between the reaction Rate Constant obtained from the stopped-flow apparatus and p K a obtained from experimental determination was then evaluated. The results showed that the Bronsted correlation could predict the Absorption Rate Constant with an AAD of 8.6%, which is within an acceptable range of 10%. By comparing through different evaluation techniques such as k 2 , p K a and Δ r G m ° , it was observed that DEAB has faster reaction kinetics than those of conventional tertiary amines, namely, DEMEA, DMMEA and MDEA.

  • kinetics of co2 Absorption into a novel 1 diethylamino 2 propanol solvent using stopped flow technique
    Aiche Journal, 2014
    Co-Authors: Zhiwu Liang, Teerawat Sema, Raphael Idem, Yanqing Na, Wichitpan Rongwong, Chen Li, Paitoon Tontiwachwuthikul
    Abstract:

    A stopped-flow apparatus was used to measure the kinetics of carbon dioxide (CO2) Absorption into aqueous solution of 1-diethylamino-2-propanol (1DEA2P) in terms of observed pseudo-first-order Rate Constant (ko) and second-order reaction Rate Constant (k2), in this work. The experiments were conducted over a 1DEA2P concentration range of 120–751 mol/m3, and a temperature range of 298–313 K. As 1DEA2P is a tertiary amine, the base-catalyzed hydration mechanism was, then, applied to correlate the experimental CO2 Absorption Rate Constants obtained from stopped-flow apparatus. In addition, the pKa of 1DEA2P was experimentally measured over a temperature range of 278–333 K. The Bronsted relationship between reaction Rate Constant (obtained from stopped-flow apparatus) and pKa was, then, studied. The results showed that the correlation based on the Bronsted relationship performed very well for predicting the Absorption Rate Constant with an absolute average deviation of 5.2%, which is in an acceptable range of less than 10%. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3502–3510, 2014