Partition Ratio

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Seiichiro Kagei - One of the best experts on this subject based on the ideXlab platform.

  • binary diffusion coefficient Partition Ratio and partial molar volume for docosahexaenoic acid eicosapentaenoic acid and α linolenic acid at infinite dilution in supercritical carbon dioxide
    Fluid Phase Equilibria, 2003
    Co-Authors: Toshitaka Funazukuri, Chang Yi Kong, Seiichiro Kagei
    Abstract:

    Abstract A tracer response technique with a poly(ethylene glycol) coated capillary column was employed to measure binary diffusion coefficient and Partition Ratio for the ω3 group of long chain unsaturated fatty acids such as docosahexaenoic acid, eicosapentaenoic acid and α-linolenic acid at infinite dilution in supercritical (SC) carbon dioxide at temperatures from 308.15 to 343.15 K and pressures from 9 to 30 MPa. The binary diffusion coefficients for each solute were expressed with the Schmidt number correlation as well as the correlation with temperature and CO2 viscosity. The Partition Ratios were correlated with temperature and CO2 density. Moreover, the partial molar volumes were obtained from the Partition Ratios for each solute.

  • measurements of binary diffusion coefficient and Partition Ratio at infinite dilution for linoleic acid and arachidonic acid in supercritical carbon dioxide
    Journal of Chemical & Engineering Data, 2003
    Co-Authors: Toshitaka Funazukuri, Chang Yi Kong, Takahiro Kikuchi, Seiichiro Kagei
    Abstract:

    The binary diffusion coefficient D12 and Partition Ratio k were measured for two ω6 group compounds, linoleic acid and arachidonic acid, at infinite dilution in carbon dioxide at temperatures from 308.15 K to 343.15 K and pressures from 9 MPa to 30 MPa by a tracer response technique with a poly(ethylene glycol)-coated capillary column. The measured D12 values were well represented by a correlation of D12/T versus CO2 viscosity and by the Schmidt number correlation for each solute, and the k values were well represented as a function of temperature and CO2 density. Partial molar volumes were also obtained from the k values.

  • infinite dilution binary diffusion coefficient Partition Ratio and partial molar volume for ubiquinone coq10 in supercritical carbon dioxide
    Industrial & Engineering Chemistry Research, 2002
    Co-Authors: Toshitaka Funazukuri, Chang Yi Kong, Seiichiro Kagei
    Abstract:

    Infinite-dilution binary diffusion coefficient D12 and Partition Ratio k for ubiquinone CoQ10 in carbon dioxide were measured by a tracer response technique with a poly(ethylene glycol)-coated capillary column at temperatures from 308.15 to 333.15 K and pressures from 8.5 to 30 MPa. D12 and k values were simultaneously determined from a measured response curve by the curve-fitting method. The fitting error between measured and calculated response curves increased with decreasing pressure, as had been the case in our previous studies on various solutes in supercritical CO2 by the Taylor dispersion method. The D12 values were correlated with temperature and CO2 viscosity and the k values with temperature and CO2 density. Moreover, partial molar volumes of CoQ10 in supercritical CO2 were obtained from the k values.

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

  • Comments on Transient analysis of stored charge in neutral base region [with reply]
    IEEE Transactions on Electron Devices, 1993
    Co-Authors: J. Parker, K. Suzuki, S. Satoh, N. Nakayama
    Abstract:

    The commenter addresses questions raised in the above-titled paper by K. Suzuki et al. (ibid., vol.39, p.1164-9, May 1992) concerning the validity of bipolar transistor models using the Partitioned-charge (PC) approach for transient simulations. Suzuki et al. assert that the concept of charge Partitioning applies only to discharge transients and thus the charge-Partition Ratio depends on the sign of the emitter-base voltage gradient, which, if true, would greatly reduce the utility of PC-based models. The commenter shows that this is not the case and that their conclusion is due only to a misinterpretation of the PC model. The authors reply.

  • Transient analysis of stored charge in neutral base region
    IEEE Transactions on Electron Devices, 1992
    Co-Authors: K. Suzuki, S. Satoh, N. Nakayama
    Abstract:

    The authors studied the transient relationship between stored charge in the neutral base region and electron current flowing through emitter and collector terminals. Stored charge flows not only through an emitter terminal but also through a collector terminal when emitter-base junction voltage decreases from the switch-on voltage to zero. The Ratio of net charge flowing through the emitter terminal to that flowing through the collector terminal is 2:1 once a steady state has been reached. No charge accumulates through the collector terminal when the emitter-base junction voltage increases from zero to the switch-on voltage, however, so the charge Partition Ratio depends on the sign of the time gradient of the emitter-base voltage.

Dick T H M Sijm - One of the best experts on this subject based on the ideXlab platform.

  • the power of size 1 rate constants and equilibrium Ratios for accumulation of organic substances related to octanol water Partition Ratio and species weight
    Environmental Toxicology and Chemistry, 2001
    Co-Authors: Jan A Hendriks, Alex Van Der Linde, Gerard Cornelissen, Dick T H M Sijm
    Abstract:

    Most of the thousands of substances and species that risk assessment has to deal with are not investigated empirically because of financial, practical, and ethical constraints. To facilitate extrapolation, we have developed a model for accumulation kinetics of organic substances as a function of the octanol-water Partition Ratio (Kow) of the chemical and the weight, lipid content, and trophic level of the species. The ecological parameters were obtained from a previous review on allometric regressions. The chemical parameters, that is, resistances that substances encounter in water and lipid layers of organisms, were calibrated on 1,939 rate constants for absorption from water for assimilation from food and for elimination. Their Ratio was validated on 37 laboratory bioconcentRation and biomagnification regressions and on 2,700 field bioaccumulation data. The rate constant for absorption increased with the hydrophobicity of the substances with a Kow up to about 1,000 and then leveled off, decreasing with the weight of the species. About 39% of the variation was explained by the model, while deviations of more than a factor of 5 were noted for labile, large, and less hydrophobic molecules as well as for algae, mollusks, and arthropods. The efficiency for assimilation of contaminants from food was determined mainly by the food digestibility and thus by the trophic level of the species. A distinction was made between substances that are stable, that is, with a minimum elimination only, and those that are labile, that is, with an excess elimination probably largely due to biotransformation. The rate constant for minimum elimination decreased with the hydrophobicity of the substance and the weight of the species. About 70% of the variation was explained by the model, while deviations of more than a factor of 5 were noted for algae, terrestrial plants, and benthic animals. Labile substances were eliminated faster than isolipophilic stable compounds, but differences in laboratory elimination and accumulation were small compared with those in field accumulation. Excess elimination by vertebrates was faster than by invertebrates. Differences between terrestrial and aquatic species were attributed to water turnover rates, whereas differences between trophic levels were due to the food digestibility. Food web accumulation, expressed as organism-organic solids and organism-food concentRations Ratios could be largely explained by ecological variables only. The model is believed to facilitate various types of scientific interpretation as well as environmental risk assessment.

  • The power of size. 1. Rate constants and equilibrium Ratios for accumulation of organic substances related to octanol‐water Partition Ratio and species weight
    Environmental Toxicology and Chemistry, 2001
    Co-Authors: A. Jan Hendriks, Alex Van Der Linde, Gerard Cornelissen, Dick T H M Sijm
    Abstract:

    Most of the thousands of substances and species that risk assessment has to deal with are not investigated empirically because of financial, practical, and ethical constraints. To facilitate extrapolation, we have developed a model for accumulation kinetics of organic substances as a function of the octanol-water Partition Ratio (Kow) of the chemical and the weight, lipid content, and trophic level of the species. The ecological parameters were obtained from a previous review on allometric regressions. The chemical parameters, that is, resistances that substances encounter in water and lipid layers of organisms, were calibrated on 1,939 rate constants for absorption from water for assimilation from food and for elimination. Their Ratio was validated on 37 laboratory bioconcentRation and biomagnification regressions and on 2,700 field bioaccumulation data. The rate constant for absorption increased with the hydrophobicity of the substances with a Kow up to about 1,000 and then leveled off, decreasing with the weight of the species. About 39% of the variation was explained by the model, while deviations of more than a factor of 5 were noted for labile, large, and less hydrophobic molecules as well as for algae, mollusks, and arthropods. The efficiency for assimilation of contaminants from food was determined mainly by the food digestibility and thus by the trophic level of the species. A distinction was made between substances that are stable, that is, with a minimum elimination only, and those that are labile, that is, with an excess elimination probably largely due to biotransformation. The rate constant for minimum elimination decreased with the hydrophobicity of the substance and the weight of the species. About 70% of the variation was explained by the model, while deviations of more than a factor of 5 were noted for algae, terrestrial plants, and benthic animals. Labile substances were eliminated faster than isolipophilic stable compounds, but differences in laboratory elimination and accumulation were small compared with those in field accumulation. Excess elimination by vertebrates was faster than by invertebrates. Differences between terrestrial and aquatic species were attributed to water turnover rates, whereas differences between trophic levels were due to the food digestibility. Food web accumulation, expressed as organism-organic solids and organism-food concentRations Ratios could be largely explained by ecological variables only. The model is believed to facilitate various types of scientific interpretation as well as environmental risk assessment.

Toshitaka Funazukuri - One of the best experts on this subject based on the ideXlab platform.

  • binary diffusion coefficient Partition Ratio and partial molar volume for docosahexaenoic acid eicosapentaenoic acid and α linolenic acid at infinite dilution in supercritical carbon dioxide
    Fluid Phase Equilibria, 2003
    Co-Authors: Toshitaka Funazukuri, Chang Yi Kong, Seiichiro Kagei
    Abstract:

    Abstract A tracer response technique with a poly(ethylene glycol) coated capillary column was employed to measure binary diffusion coefficient and Partition Ratio for the ω3 group of long chain unsaturated fatty acids such as docosahexaenoic acid, eicosapentaenoic acid and α-linolenic acid at infinite dilution in supercritical (SC) carbon dioxide at temperatures from 308.15 to 343.15 K and pressures from 9 to 30 MPa. The binary diffusion coefficients for each solute were expressed with the Schmidt number correlation as well as the correlation with temperature and CO2 viscosity. The Partition Ratios were correlated with temperature and CO2 density. Moreover, the partial molar volumes were obtained from the Partition Ratios for each solute.

  • measurements of binary diffusion coefficient and Partition Ratio at infinite dilution for linoleic acid and arachidonic acid in supercritical carbon dioxide
    Journal of Chemical & Engineering Data, 2003
    Co-Authors: Toshitaka Funazukuri, Chang Yi Kong, Takahiro Kikuchi, Seiichiro Kagei
    Abstract:

    The binary diffusion coefficient D12 and Partition Ratio k were measured for two ω6 group compounds, linoleic acid and arachidonic acid, at infinite dilution in carbon dioxide at temperatures from 308.15 K to 343.15 K and pressures from 9 MPa to 30 MPa by a tracer response technique with a poly(ethylene glycol)-coated capillary column. The measured D12 values were well represented by a correlation of D12/T versus CO2 viscosity and by the Schmidt number correlation for each solute, and the k values were well represented as a function of temperature and CO2 density. Partial molar volumes were also obtained from the k values.

  • infinite dilution binary diffusion coefficient Partition Ratio and partial molar volume for ubiquinone coq10 in supercritical carbon dioxide
    Industrial & Engineering Chemistry Research, 2002
    Co-Authors: Toshitaka Funazukuri, Chang Yi Kong, Seiichiro Kagei
    Abstract:

    Infinite-dilution binary diffusion coefficient D12 and Partition Ratio k for ubiquinone CoQ10 in carbon dioxide were measured by a tracer response technique with a poly(ethylene glycol)-coated capillary column at temperatures from 308.15 to 333.15 K and pressures from 8.5 to 30 MPa. D12 and k values were simultaneously determined from a measured response curve by the curve-fitting method. The fitting error between measured and calculated response curves increased with decreasing pressure, as had been the case in our previous studies on various solutes in supercritical CO2 by the Taylor dispersion method. The D12 values were correlated with temperature and CO2 viscosity and the k values with temperature and CO2 density. Moreover, partial molar volumes of CoQ10 in supercritical CO2 were obtained from the k values.

Silvio Sicardi - One of the best experts on this subject based on the ideXlab platform.

  • dye uptake and Partition Ratio of disperse dyes between a pet yarn and supercritical carbon dioxide
    Journal of Supercritical Fluids, 2006
    Co-Authors: Ada Ferri, Mauro Banchero, Luigi Manna, Silvio Sicardi
    Abstract:

    Abstract The equilibrium uptake of three disperse azoic dyes in a commercial PET yarn in presence of supercritical carbon dioxide was measured. The dye uptake was found to be much more sensitive to temperature than to pressure in the tested operative conditions. The equilibrium Partition coefficient between the fibre and the supercritical fluid was evaluated from previously measured solubility data [A. Ferri, M. Banchero, L. Manna, S. Sicardi, An experimental technique for measuring high solubilities of dyes in supercritical carbon dioxide, J. Supercrit. Fluids 30 (2004) 41; A. Ferri, M. Banchero, L. Manna, S. Sicardi, A new correlation of solubilities of azoic compounds and anthraquinone derivatives in supercritical carbon dioxide, J. Supercrit. Fluids 32 (2004) 27]. The high values of the Partition coefficients demonstrated that the Partition of the dye between the fluid and the polymer is an important parameter to evaluate the feasibility of the dyeing process in supercritical carbon dioxide. The Partition coefficients were correlated with three equations: an equation proposed by Funazukuri et al. with four fitting parameters [Ind. Eng. Chem. Res. 41 (2002) 2812]; a semi-empirical equation, with five fitting parameters, that was developed assuming a Langmuir-type absorption of the dyes into the yarn; and an empirical equation, with three fitting parameters, developed from simple experimental data observation. The best agreement was obtained with the second, semi-empirical equation. Good results were also obtained with the third, empirical equation and the agreement with experimental data was better than that obtained with the equation proposed by Funazukuri et al. even though it makes use of one fitting parameter less.