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Masahiro Ikoma - One of the best experts on this subject based on the ideXlab platform.
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formation of aqua planets with water of nebular origin effects of water enrichment on the structure and mass of captured atmospheres of terrestrial planets
Monthly Notices of the Royal Astronomical Society, 2020Co-Authors: Tadahiro Kimura, Masahiro IkomaAbstract:Recent detection of exoplanets with Earth-like insolation attracts growing interest in how common Earth-like aqua planets are beyond the solar system. While terrestrial planets are often assumed to capture icy or water-rich planetesimals, a primordial atmosphere of nebular origin itself can produce water through oxidation of the atmospheric hydrogen with oxidising minerals from incoming planetesimals or the magma ocean. Thermodynamically, normal oxygen buffers produce water comparable in Mole Number to or more than hydrogen. Thus, the primordial atmosphere would likely be highly enriched with water vapour; however, the primordial atmosphereshave been always assumed to have the solar abundances. Here we integrate the 1D structure of such an enriched atmosphere of sub-Earths embedded in a protoplanetary disc around an M dwarf of 0.3$M_\odot$ and investigate the effects of water enrichment on the atmospheric properties with focus on water amount. We find that the well-mixed, highly-enriched atmosphere is more massive by a few orders of magnitude than the solar-abundance atmosphere, and that even a Mars-mass planet can obtain water comparable to the present Earth's oceans. Although close-in Mars-mass planets likely lose the captured water via disc dispersal and photo-evaporation, these results suggest that there are more sub-Earths with Earth-like water contents than previously predicted. How much water terrestrial planets really obtain and retain against subsequent loss, however, depends on efficiencies of water production, mixing in the atmosphere and magma ocean, and photo-evaporation, detailed investigation for which should be made in the future.
Tadahiro Kimura - One of the best experts on this subject based on the ideXlab platform.
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formation of aqua planets with water of nebular origin effects of water enrichment on the structure and mass of captured atmospheres of terrestrial planets
Monthly Notices of the Royal Astronomical Society, 2020Co-Authors: Tadahiro Kimura, Masahiro IkomaAbstract:Recent detection of exoplanets with Earth-like insolation attracts growing interest in how common Earth-like aqua planets are beyond the solar system. While terrestrial planets are often assumed to capture icy or water-rich planetesimals, a primordial atmosphere of nebular origin itself can produce water through oxidation of the atmospheric hydrogen with oxidising minerals from incoming planetesimals or the magma ocean. Thermodynamically, normal oxygen buffers produce water comparable in Mole Number to or more than hydrogen. Thus, the primordial atmosphere would likely be highly enriched with water vapour; however, the primordial atmosphereshave been always assumed to have the solar abundances. Here we integrate the 1D structure of such an enriched atmosphere of sub-Earths embedded in a protoplanetary disc around an M dwarf of 0.3$M_\odot$ and investigate the effects of water enrichment on the atmospheric properties with focus on water amount. We find that the well-mixed, highly-enriched atmosphere is more massive by a few orders of magnitude than the solar-abundance atmosphere, and that even a Mars-mass planet can obtain water comparable to the present Earth's oceans. Although close-in Mars-mass planets likely lose the captured water via disc dispersal and photo-evaporation, these results suggest that there are more sub-Earths with Earth-like water contents than previously predicted. How much water terrestrial planets really obtain and retain against subsequent loss, however, depends on efficiencies of water production, mixing in the atmosphere and magma ocean, and photo-evaporation, detailed investigation for which should be made in the future.
Jian Zhang - One of the best experts on this subject based on the ideXlab platform.
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a thermodynamic model for representation reaction abilities of structural units in full composition range of fe si binary melts based on the atom Molecule coexistence theory
Steel Research International, 2013Co-Authors: Xuemin Yang, Meng Zhang, Jian ZhangAbstract:A thermodynamic model for calculating the mass action concentrations of structural units in Fe-Si binary melts based on the atom-Molecule coexistence theory, i.e., the AMC N-i model, has been developed and verified through comparing with the reported activities of both Si and Fe in the full composition range of Fe-Si binary melts at temperatures of 1693, 1773, 1873, and 1973K from the literature. N-Si of free Si or N-Fe of free Fe in the full composition range of Fe-Si binary melts has a good 1:1 corresponding relationship with the reported activity a(R,Si) of Si or a(R,Fe) of Fe relative to pure liquid Si(l) or Fe(l) as standard state. N-Si of free Si has a good corresponding relationship with the calculated activity a(%,Si) of Si referred to 1mass% of Si as standard state as well as the calculated activity a(H,Si) of Si relative to the hypothetical pure liquid Si(l) as standard state. a(%,Si) or a(H,Si) of Si is much greater than the calculated mass action concentration N-Si of free Si in Fe-Si binary melts. N-i of six structural units as Fe, Si, Fe2Si, Fe5Si3, FeSi, and FeSi2 cannot show the linear relationship with the calculated equilibrium Mole Numbers n(i) in 100-g Fe-Si binary melts simultaneously. A spindle-type relationship between the calculated mass action concentration N-i and the calculated equilibrium Mole Number n(i) of FeSi and FeSi2 in Fe-Si binary melts has been found.
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a thermodynamic model for representation reaction abilities of structural units in fe s binary melts based on the atom Molecule coexistence theory
Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, 2012Co-Authors: Xuemin Yang, Meng Zhang, Jianliang Zhang, Jian ZhangAbstract:A thermodynamic model for calculating the mass action concentrations of structural units in Fe-S binary melts based on the atom-Molecule coexistence theory, i.e., AMCT-N i model, has been developed and verified through a comparison with the reported activities of both S and Fe in Fe-S binary melts with changing Mole fraction \( x_{\text{S}} \) of S from 0.0 to 0.095 at temperatures of 1773 K, 1823 K, and 1873 K (1500 °C, 1550 °C, and 1600 °C) from the literature. The calculated mass action concentration \( N_{\text{S}} \) of S is much smaller than the reported activity \( a_{\text{R, S}} \) of S in Fe-S binary melts with changing Mole fraction \( x_{\text{S}} \) of S from 0.0 to 0.095. The calculated mass action concentration \( N_{\text{S}} \) of S can correlate the reliable 1:1 corresponding relationship with the reported activity \( a_{\text{R, S}} \) or \( a_{\%,\text {S}} \) of S through the introduced transformation coefficients with absolutely mathematical meaning or through the defined comprehensive mass action concentration of total S with explicitly physicochemical meaning. The calculated mass action concentrations \( N_{i} \) of structural units from the developed AMCT-N i thermodynamic model can be applied to describe or predict the reaction abilities of structural units in Fe-S binary melts. The reaction abilities of Fe and S show a competitive relationship each other in Fe-S binary melts in a temperature range from 1773 K to 1873 K (1500 °C to 1600 °C). The calculated mass action concentration \( N_{{{\text{FeS}}_{ 2} }} \) of FeS2 is very small and can be ignored because FeS2 can be incongruently decomposed above 1016 K (743 °C). The very small values for the calculated mass action concentrations \( N_{{{\text{FeS}}_{ 2} }} \) of FeS2 in a range of Mole fraction \( x_{\text{S}} \) of S from 0.0 to 1.0 as well as a maximum value for the calculated mass action concentration \( N_{\text{FeS}} \) of FeS with Mole fraction \( x_{\text{S}} \) of S as 0.5 are coincident with diagram phase of Fe-S binary melts. A spindle-type relationship between the calculated mass action concentration \( N_{i} \) and the calculated equilibrium Mole Number \( n_{i} \) can be found for FeS and FeS2 in Fe-S binary melts. The Raoultian activity coefficient \( \gamma_{S}^{0} \) of S relative to pure liquid S(l) as standard state and the infinitely dilute solution as reference state in Fe-S binary melts can be determined as 1.0045 in a temperature range from 1773 K to 1873 K (1500 °C to 1600 °C). The standard molar Gibbs free energy change \( \Updelta_{\text{sol}} G_{{{\text{m, S }}({\text{l}}) \to [{\text{S}}]_{{ \, [{\text{pct \, S}}] = 1.0}} }}^{{\Uptheta,\%}} \) of dissolving liquid S for forming [pct S] as 1.0 in Fe-S binary melts relative to 1 mass percentage of S as standard state can be formulated as \( \Updelta_{\text{sol}} G_{{{\text{m, S }}({\text{l}}) \to [{\text{S}}]_{{ \, [{\text{pct \, S] }} = \, 1.0}} }}^{{\Uptheta,\, \%}} \,\, = -0.219\,-\,33.70T\,\,\left( {\text{J/mol}} \right).\)
Meng Zhang - One of the best experts on this subject based on the ideXlab platform.
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a thermodynamic model for representation reaction abilities of structural units in full composition range of fe si binary melts based on the atom Molecule coexistence theory
Steel Research International, 2013Co-Authors: Xuemin Yang, Meng Zhang, Jian ZhangAbstract:A thermodynamic model for calculating the mass action concentrations of structural units in Fe-Si binary melts based on the atom-Molecule coexistence theory, i.e., the AMC N-i model, has been developed and verified through comparing with the reported activities of both Si and Fe in the full composition range of Fe-Si binary melts at temperatures of 1693, 1773, 1873, and 1973K from the literature. N-Si of free Si or N-Fe of free Fe in the full composition range of Fe-Si binary melts has a good 1:1 corresponding relationship with the reported activity a(R,Si) of Si or a(R,Fe) of Fe relative to pure liquid Si(l) or Fe(l) as standard state. N-Si of free Si has a good corresponding relationship with the calculated activity a(%,Si) of Si referred to 1mass% of Si as standard state as well as the calculated activity a(H,Si) of Si relative to the hypothetical pure liquid Si(l) as standard state. a(%,Si) or a(H,Si) of Si is much greater than the calculated mass action concentration N-Si of free Si in Fe-Si binary melts. N-i of six structural units as Fe, Si, Fe2Si, Fe5Si3, FeSi, and FeSi2 cannot show the linear relationship with the calculated equilibrium Mole Numbers n(i) in 100-g Fe-Si binary melts simultaneously. A spindle-type relationship between the calculated mass action concentration N-i and the calculated equilibrium Mole Number n(i) of FeSi and FeSi2 in Fe-Si binary melts has been found.
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a thermodynamic model for representation reaction abilities of structural units in fe s binary melts based on the atom Molecule coexistence theory
Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, 2012Co-Authors: Xuemin Yang, Meng Zhang, Jianliang Zhang, Jian ZhangAbstract:A thermodynamic model for calculating the mass action concentrations of structural units in Fe-S binary melts based on the atom-Molecule coexistence theory, i.e., AMCT-N i model, has been developed and verified through a comparison with the reported activities of both S and Fe in Fe-S binary melts with changing Mole fraction \( x_{\text{S}} \) of S from 0.0 to 0.095 at temperatures of 1773 K, 1823 K, and 1873 K (1500 °C, 1550 °C, and 1600 °C) from the literature. The calculated mass action concentration \( N_{\text{S}} \) of S is much smaller than the reported activity \( a_{\text{R, S}} \) of S in Fe-S binary melts with changing Mole fraction \( x_{\text{S}} \) of S from 0.0 to 0.095. The calculated mass action concentration \( N_{\text{S}} \) of S can correlate the reliable 1:1 corresponding relationship with the reported activity \( a_{\text{R, S}} \) or \( a_{\%,\text {S}} \) of S through the introduced transformation coefficients with absolutely mathematical meaning or through the defined comprehensive mass action concentration of total S with explicitly physicochemical meaning. The calculated mass action concentrations \( N_{i} \) of structural units from the developed AMCT-N i thermodynamic model can be applied to describe or predict the reaction abilities of structural units in Fe-S binary melts. The reaction abilities of Fe and S show a competitive relationship each other in Fe-S binary melts in a temperature range from 1773 K to 1873 K (1500 °C to 1600 °C). The calculated mass action concentration \( N_{{{\text{FeS}}_{ 2} }} \) of FeS2 is very small and can be ignored because FeS2 can be incongruently decomposed above 1016 K (743 °C). The very small values for the calculated mass action concentrations \( N_{{{\text{FeS}}_{ 2} }} \) of FeS2 in a range of Mole fraction \( x_{\text{S}} \) of S from 0.0 to 1.0 as well as a maximum value for the calculated mass action concentration \( N_{\text{FeS}} \) of FeS with Mole fraction \( x_{\text{S}} \) of S as 0.5 are coincident with diagram phase of Fe-S binary melts. A spindle-type relationship between the calculated mass action concentration \( N_{i} \) and the calculated equilibrium Mole Number \( n_{i} \) can be found for FeS and FeS2 in Fe-S binary melts. The Raoultian activity coefficient \( \gamma_{S}^{0} \) of S relative to pure liquid S(l) as standard state and the infinitely dilute solution as reference state in Fe-S binary melts can be determined as 1.0045 in a temperature range from 1773 K to 1873 K (1500 °C to 1600 °C). The standard molar Gibbs free energy change \( \Updelta_{\text{sol}} G_{{{\text{m, S }}({\text{l}}) \to [{\text{S}}]_{{ \, [{\text{pct \, S}}] = 1.0}} }}^{{\Uptheta,\%}} \) of dissolving liquid S for forming [pct S] as 1.0 in Fe-S binary melts relative to 1 mass percentage of S as standard state can be formulated as \( \Updelta_{\text{sol}} G_{{{\text{m, S }}({\text{l}}) \to [{\text{S}}]_{{ \, [{\text{pct \, S] }} = \, 1.0}} }}^{{\Uptheta,\, \%}} \,\, = -0.219\,-\,33.70T\,\,\left( {\text{J/mol}} \right).\)
Shevtsova Valentina - One of the best experts on this subject based on the ideXlab platform.
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Do ternary liquid mixtures exhibit negative main Fick diffusion coefficients?
'Royal Society of Chemistry (RSC)', 2019Co-Authors: Kozlova Sofia, Mialdun Aliaksndr, Janzen Tatjana, Vrabec Jadran, Shevtsova ValentinaAbstract:Experimental data on Fick diffusion coefficients of ternary and higher mixtures depend on the reference frame; those which are in common use are associated with the average velocity either with respect to volume, mass or Mole Number. In this study, the dependence of diffusion coefficients on the reference frame is thoroughly analyzed for three ternary mixtures of different types. The first one, tetralin-isobutylbenzene-dodecane, can almost be considered as ideal, the second one, cyclohexane-toluene-methanol, exhibits liquid-liquid phase separation and the third one, water-ethanol-triethylene glycol, contains three associating species and is also strongly non-ideal. Experimental diffusion coefficient data sampled in the volume reference frame are transformed to the molar and mass reference frames. The required partial molar volumes are derived from present density measurements. Four additional mixtures are considered along a single or two composition paths. A highlight of this study is the existence of a strong similarity of the main diffusion coefficients in the volume and mass reference frames for all considered mixtures. When the excess volume is small, the coefficients in the molar reference frame are also similar. However, for the mixture with a large excess volume (containing water), the diffusion coefficients in the molar reference frame differ significantly, even indicating negative main diffusion coefficients. It is shown that negative main diffusion coefficients appear due to relatively large experimental uncertainties of cross diffusion coefficients, which are propagated and amplified by frame transformation.SCOPUS: ar.jinfo:eu-repo/semantics/publishe