The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Hiroki Itasaka - One of the best experts on this subject based on the ideXlab platform.
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Role of partial molar enthalpy of oxides on Soret Effect in high-temperature CaO–SiO 2 melts
Scientific reports, 2018Co-Authors: Masahiro Shimizu, Jun Matsuoka, Masayuki Nishi, Yasuhiko Shimotsuma, Hiroshi Kato, Takeyuki Kato, Heidy Visbal, Kohji Nagashima, Masaaki Sakakura, Hiroki ItasakaAbstract:The Soret Effect or thermodiffusion is the temperature-gradient driven diffusion in a multicomponent system. Two important conclusions have been obtained for the Soret Effect in multicomponent silicate melts: first, the SiO2 component concentrates in the hot region; and second, heavier isotopes concentrate in the cold region more than lighter isotopes. For the second point, the isotope fractionation can be explained by the classical mechanical collisions between pairs of particles. However, as for the first point, no physical model has been reported to answer why the SiO2 component concentrates in the hot region. We try to address this issue by simulating the composition dependence of the Soret Effect in CaO-SiO2 melts with nonequilibrium molecular dynamics and determining through a comparison of the results with those calculated from the Kempers model that partial molar enthalpy is one of the dominant factors in this phenomenon.
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role of partial molar enthalpy of oxides on Soret Effect in high temperature cao sio 2 melts
Scientific Reports, 2018Co-Authors: Masahiro Shimizu, Jun Matsuoka, Masayuki Nishi, Yasuhiko Shimotsuma, Hiroshi Kato, Takeyuki Kato, Heidy Visbal, Kohji Nagashima, Masaaki Sakakura, Hiroki ItasakaAbstract:The Soret Effect or thermodiffusion is the temperature-gradient driven diffusion in a multicomponent system. Two important conclusions have been obtained for the Soret Effect in multicomponent silicate melts: first, the SiO2 component concentrates in the hot region; and second, heavier isotopes concentrate in the cold region more than lighter isotopes. For the second point, the isotope fractionation can be explained by the classical mechanical collisions between pairs of particles. However, as for the first point, no physical model has been reported to answer why the SiO2 component concentrates in the hot region. We try to address this issue by simulating the composition dependence of the Soret Effect in CaO-SiO2 melts with nonequilibrium molecular dynamics and determining through a comparison of the results with those calculated from the Kempers model that partial molar enthalpy is one of the dominant factors in this phenomenon.
Masahiro Shimizu - One of the best experts on this subject based on the ideXlab platform.
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Determination of thermodynamic and microscopic origins of the Soret Effect in sodium silicate melts: Prediction of sign change of the Soret coefficient.
The Journal of chemical physics, 2021Co-Authors: Masahiro Shimizu, Tsubasa Fukuyo, Jun Matsuoka, Kento Nakashima, Kenzo Sato, Tomohiro Kiyosawa, Masayuki Nishi, Yasuhiko Shimotsuma, Kiyotaka MiuraAbstract:The Soret Effect in silicate melts has attracted attention in earth and material sciences, particularly in glass science and engineering, because a compositional change caused by the Soret Effect modifies the material properties of silicate melts. We investigated the Soret Effect in an Na2O–SiO2 system, which is the most common representative of silicate melts. Our theoretical approach based on the modified Kempers model and non-equilibrium molecular dynamics simulation was validated for 30Na2O–70SiO2(mol. %). The sign and order of the absolute values of the calculated Soret coefficients were consistent with the experimental values. The positive Soret coefficient of SiO2 in the SiO2-poor composition range was accurately predicted. Previous experimental studies have focused on SiO2-rich compositions, and only the negative sign, indicating SiO2 migration to the hot side, has been observed. In the SiO2-poor composition range, the Q0 structure was dominant and had four Si–O–Na bonds around an SiO4 unit. The Si–O–Na bond had high enthalpic stability and contributed to the large negative enthalpy of SiO2 mixing. According to our model, components with a large negative partial molar enthalpy of mixing will concentrate in the cold region. The microscopic and thermodynamic origins of the sign change in the Soret Effect were determined.
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Role of partial molar enthalpy of oxides on Soret Effect in high-temperature CaO–SiO 2 melts
Scientific reports, 2018Co-Authors: Masahiro Shimizu, Jun Matsuoka, Masayuki Nishi, Yasuhiko Shimotsuma, Hiroshi Kato, Takeyuki Kato, Heidy Visbal, Kohji Nagashima, Masaaki Sakakura, Hiroki ItasakaAbstract:The Soret Effect or thermodiffusion is the temperature-gradient driven diffusion in a multicomponent system. Two important conclusions have been obtained for the Soret Effect in multicomponent silicate melts: first, the SiO2 component concentrates in the hot region; and second, heavier isotopes concentrate in the cold region more than lighter isotopes. For the second point, the isotope fractionation can be explained by the classical mechanical collisions between pairs of particles. However, as for the first point, no physical model has been reported to answer why the SiO2 component concentrates in the hot region. We try to address this issue by simulating the composition dependence of the Soret Effect in CaO-SiO2 melts with nonequilibrium molecular dynamics and determining through a comparison of the results with those calculated from the Kempers model that partial molar enthalpy is one of the dominant factors in this phenomenon.
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role of partial molar enthalpy of oxides on Soret Effect in high temperature cao sio 2 melts
Scientific Reports, 2018Co-Authors: Masahiro Shimizu, Jun Matsuoka, Masayuki Nishi, Yasuhiko Shimotsuma, Hiroshi Kato, Takeyuki Kato, Heidy Visbal, Kohji Nagashima, Masaaki Sakakura, Hiroki ItasakaAbstract:The Soret Effect or thermodiffusion is the temperature-gradient driven diffusion in a multicomponent system. Two important conclusions have been obtained for the Soret Effect in multicomponent silicate melts: first, the SiO2 component concentrates in the hot region; and second, heavier isotopes concentrate in the cold region more than lighter isotopes. For the second point, the isotope fractionation can be explained by the classical mechanical collisions between pairs of particles. However, as for the first point, no physical model has been reported to answer why the SiO2 component concentrates in the hot region. We try to address this issue by simulating the composition dependence of the Soret Effect in CaO-SiO2 melts with nonequilibrium molecular dynamics and determining through a comparison of the results with those calculated from the Kempers model that partial molar enthalpy is one of the dominant factors in this phenomenon.
Leo J.t.m. Kempers - One of the best experts on this subject based on the ideXlab platform.
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A Comprehensive Theory of the Soret Effect in a Multicomponent Mixture
Thermal Nonequilibrium Phenomena in Fluid Mixtures, 2002Co-Authors: Leo J.t.m. KempersAbstract:A comprehensive theory for the Soret Effect (also called: Ludwig-Soret Effect and thermal diffusion) is presented which incorporates both the thermodynamic contribution and the kinetic contribution. The new theory is an extension of a theory presented in our previous paper (J. Chem. Phys. (1989) 90, 6541) in which the thermodynamic contribution only was modelled. The single assumption of the theory is that the Soret Effect in the steady state is the macroscopic state accomplished by a maximum number of microstates with respect to the ideal gas state. The methodology of the new theory, which can be used to model other cross-Effects in irreversible thermodynamics, is further validated by application to the textbook case of gravity equilibrium in an isothermal fluid column. As a result, the Soret Effect in a multicomponent mixture can be calculated by using input from an equation-of-state of the mixture and kinetic gas theory.
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A comprehensive thermodynamic theory of the Soret Effect in a multicomponent gas, liquid, or solid
The Journal of Chemical Physics, 2001Co-Authors: Leo J.t.m. KempersAbstract:A comprehensive theory for the Soret Effect (also called thermal diffusion) is presented which incorporates both the thermodynamic contribution from selective attraction/repulsion and the kinetic contribution from selective collision interaction between the components. The new theory is an extension of a theory presented earlier in which the thermodynamic contribution only was modeled. The single assumption of the theory is that the Soret Effect in the steady state is the macroscopic state accomplished by a maximum number of microstates with respect to the ideal gas state. As a result, the Soret Effect in a multicomponent mixture can be calculated by using input from an equation-of-state of the mixture and kinetic gas theory without the use of matching parameters. The theory is not limited to systems with a small temperature difference and/or a small concentration difference. The methodology of the new theory can be used to model other cross-Effects in irreversible thermodynamics. A test of the theory against the measured Soret Effect in 18 mixtures shows agreement within a factor of 2 over four decades. Closer agreement cannot be expected since it appears that the calculation of the Soret Effect is extremely sensitive to the accuracy of input from the equation-of-state. The present equations-of-state, even those that are calibrated for use in the chemical and petroleum industry, require modification for the calculation of the Soret Effect, because of a higher demand in accuracy. In addition, it is also important to examine which frame of reference (center-of-volume or center-of-mass) applies to a particular measurement or practical application, because the frame of reference determines which mathematical expression for the Soret Effect must be used.
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a comprehensive thermodynamic theory of the Soret Effect in a multicomponent gas liquid or solid
Journal of Chemical Physics, 2001Co-Authors: Leo J.t.m. KempersAbstract:A comprehensive theory for the Soret Effect (also called thermal diffusion) is presented which incorporates both the thermodynamic contribution from selective attraction/repulsion and the kinetic contribution from selective collision interaction between the components. The new theory is an extension of a theory presented earlier in which the thermodynamic contribution only was modeled. The single assumption of the theory is that the Soret Effect in the steady state is the macroscopic state accomplished by a maximum number of microstates with respect to the ideal gas state. As a result, the Soret Effect in a multicomponent mixture can be calculated by using input from an equation-of-state of the mixture and kinetic gas theory without the use of matching parameters. The theory is not limited to systems with a small temperature difference and/or a small concentration difference. The methodology of the new theory can be used to model other cross-Effects in irreversible thermodynamics. A test of the theory aga...
Jun Matsuoka - One of the best experts on this subject based on the ideXlab platform.
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Determination of thermodynamic and microscopic origins of the Soret Effect in sodium silicate melts: Prediction of sign change of the Soret coefficient.
The Journal of chemical physics, 2021Co-Authors: Masahiro Shimizu, Tsubasa Fukuyo, Jun Matsuoka, Kento Nakashima, Kenzo Sato, Tomohiro Kiyosawa, Masayuki Nishi, Yasuhiko Shimotsuma, Kiyotaka MiuraAbstract:The Soret Effect in silicate melts has attracted attention in earth and material sciences, particularly in glass science and engineering, because a compositional change caused by the Soret Effect modifies the material properties of silicate melts. We investigated the Soret Effect in an Na2O–SiO2 system, which is the most common representative of silicate melts. Our theoretical approach based on the modified Kempers model and non-equilibrium molecular dynamics simulation was validated for 30Na2O–70SiO2(mol. %). The sign and order of the absolute values of the calculated Soret coefficients were consistent with the experimental values. The positive Soret coefficient of SiO2 in the SiO2-poor composition range was accurately predicted. Previous experimental studies have focused on SiO2-rich compositions, and only the negative sign, indicating SiO2 migration to the hot side, has been observed. In the SiO2-poor composition range, the Q0 structure was dominant and had four Si–O–Na bonds around an SiO4 unit. The Si–O–Na bond had high enthalpic stability and contributed to the large negative enthalpy of SiO2 mixing. According to our model, components with a large negative partial molar enthalpy of mixing will concentrate in the cold region. The microscopic and thermodynamic origins of the sign change in the Soret Effect were determined.
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Role of partial molar enthalpy of oxides on Soret Effect in high-temperature CaO–SiO 2 melts
Scientific reports, 2018Co-Authors: Masahiro Shimizu, Jun Matsuoka, Masayuki Nishi, Yasuhiko Shimotsuma, Hiroshi Kato, Takeyuki Kato, Heidy Visbal, Kohji Nagashima, Masaaki Sakakura, Hiroki ItasakaAbstract:The Soret Effect or thermodiffusion is the temperature-gradient driven diffusion in a multicomponent system. Two important conclusions have been obtained for the Soret Effect in multicomponent silicate melts: first, the SiO2 component concentrates in the hot region; and second, heavier isotopes concentrate in the cold region more than lighter isotopes. For the second point, the isotope fractionation can be explained by the classical mechanical collisions between pairs of particles. However, as for the first point, no physical model has been reported to answer why the SiO2 component concentrates in the hot region. We try to address this issue by simulating the composition dependence of the Soret Effect in CaO-SiO2 melts with nonequilibrium molecular dynamics and determining through a comparison of the results with those calculated from the Kempers model that partial molar enthalpy is one of the dominant factors in this phenomenon.
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role of partial molar enthalpy of oxides on Soret Effect in high temperature cao sio 2 melts
Scientific Reports, 2018Co-Authors: Masahiro Shimizu, Jun Matsuoka, Masayuki Nishi, Yasuhiko Shimotsuma, Hiroshi Kato, Takeyuki Kato, Heidy Visbal, Kohji Nagashima, Masaaki Sakakura, Hiroki ItasakaAbstract:The Soret Effect or thermodiffusion is the temperature-gradient driven diffusion in a multicomponent system. Two important conclusions have been obtained for the Soret Effect in multicomponent silicate melts: first, the SiO2 component concentrates in the hot region; and second, heavier isotopes concentrate in the cold region more than lighter isotopes. For the second point, the isotope fractionation can be explained by the classical mechanical collisions between pairs of particles. However, as for the first point, no physical model has been reported to answer why the SiO2 component concentrates in the hot region. We try to address this issue by simulating the composition dependence of the Soret Effect in CaO-SiO2 melts with nonequilibrium molecular dynamics and determining through a comparison of the results with those calculated from the Kempers model that partial molar enthalpy is one of the dominant factors in this phenomenon.
Masayuki Nishi - One of the best experts on this subject based on the ideXlab platform.
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Determination of thermodynamic and microscopic origins of the Soret Effect in sodium silicate melts: Prediction of sign change of the Soret coefficient.
The Journal of chemical physics, 2021Co-Authors: Masahiro Shimizu, Tsubasa Fukuyo, Jun Matsuoka, Kento Nakashima, Kenzo Sato, Tomohiro Kiyosawa, Masayuki Nishi, Yasuhiko Shimotsuma, Kiyotaka MiuraAbstract:The Soret Effect in silicate melts has attracted attention in earth and material sciences, particularly in glass science and engineering, because a compositional change caused by the Soret Effect modifies the material properties of silicate melts. We investigated the Soret Effect in an Na2O–SiO2 system, which is the most common representative of silicate melts. Our theoretical approach based on the modified Kempers model and non-equilibrium molecular dynamics simulation was validated for 30Na2O–70SiO2(mol. %). The sign and order of the absolute values of the calculated Soret coefficients were consistent with the experimental values. The positive Soret coefficient of SiO2 in the SiO2-poor composition range was accurately predicted. Previous experimental studies have focused on SiO2-rich compositions, and only the negative sign, indicating SiO2 migration to the hot side, has been observed. In the SiO2-poor composition range, the Q0 structure was dominant and had four Si–O–Na bonds around an SiO4 unit. The Si–O–Na bond had high enthalpic stability and contributed to the large negative enthalpy of SiO2 mixing. According to our model, components with a large negative partial molar enthalpy of mixing will concentrate in the cold region. The microscopic and thermodynamic origins of the sign change in the Soret Effect were determined.
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Role of partial molar enthalpy of oxides on Soret Effect in high-temperature CaO–SiO 2 melts
Scientific reports, 2018Co-Authors: Masahiro Shimizu, Jun Matsuoka, Masayuki Nishi, Yasuhiko Shimotsuma, Hiroshi Kato, Takeyuki Kato, Heidy Visbal, Kohji Nagashima, Masaaki Sakakura, Hiroki ItasakaAbstract:The Soret Effect or thermodiffusion is the temperature-gradient driven diffusion in a multicomponent system. Two important conclusions have been obtained for the Soret Effect in multicomponent silicate melts: first, the SiO2 component concentrates in the hot region; and second, heavier isotopes concentrate in the cold region more than lighter isotopes. For the second point, the isotope fractionation can be explained by the classical mechanical collisions between pairs of particles. However, as for the first point, no physical model has been reported to answer why the SiO2 component concentrates in the hot region. We try to address this issue by simulating the composition dependence of the Soret Effect in CaO-SiO2 melts with nonequilibrium molecular dynamics and determining through a comparison of the results with those calculated from the Kempers model that partial molar enthalpy is one of the dominant factors in this phenomenon.
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role of partial molar enthalpy of oxides on Soret Effect in high temperature cao sio 2 melts
Scientific Reports, 2018Co-Authors: Masahiro Shimizu, Jun Matsuoka, Masayuki Nishi, Yasuhiko Shimotsuma, Hiroshi Kato, Takeyuki Kato, Heidy Visbal, Kohji Nagashima, Masaaki Sakakura, Hiroki ItasakaAbstract:The Soret Effect or thermodiffusion is the temperature-gradient driven diffusion in a multicomponent system. Two important conclusions have been obtained for the Soret Effect in multicomponent silicate melts: first, the SiO2 component concentrates in the hot region; and second, heavier isotopes concentrate in the cold region more than lighter isotopes. For the second point, the isotope fractionation can be explained by the classical mechanical collisions between pairs of particles. However, as for the first point, no physical model has been reported to answer why the SiO2 component concentrates in the hot region. We try to address this issue by simulating the composition dependence of the Soret Effect in CaO-SiO2 melts with nonequilibrium molecular dynamics and determining through a comparison of the results with those calculated from the Kempers model that partial molar enthalpy is one of the dominant factors in this phenomenon.
