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Gab Abramowitz - One of the best experts on this subject based on the ideXlab platform.
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Response of microbial decomposition to spin-up explains CMIP5 soil Carbon Range until 2100
Geoscientific Model Development, 2014Co-Authors: Jean-françois Exbrayat, Andrew J. Pitman, Gab AbramowitzAbstract:Abstract. Soil Carbon storage simulated by the Coupled Model Intercomparison Project (CMIP5) models varies 6-fold for the present day. Here, we confirm earlier work showing that this Range already exists at the beginning of the CMIP5 historical simulations. We additionally show that this Range is largely determined by the response of microbial decomposition during each model's spin-up procedure from initialization to equilibration. The 6-fold Range in soil Carbon, once established prior to the beginning of the historical period (and prior to the beginning of a CMIP5 simulation), is then maintained through the present and to 2100 almost unchanged even under a strong business-as-usual emissions scenario. We therefore highlight that a commonly ignored part of CMIP5 analyses – the land surface state achieved through the spin-up procedure – can be important for determining future Carbon storage and land surface fluxes. We identify the need to better constrain the outcome of the spin-up procedure as an important step in reducing uncertainty in both projected soil Carbon and land surface fluxes in CMIP5 transient simulations.
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Response of microbial decomposition to spin-up explains CMIP5 soil Carbon Range until 2100
Geoscientific Model Development Discussions, 2014Co-Authors: Jean-françois Exbrayat, Andrew J. Pitman, Gab AbramowitzAbstract:Abstract. Soil Carbon storage simulated by the Coupled Model Intercomparison Project (CMIP5) models varies 6-fold for the present day. We show that this Range already exists at the beginning of the historical simulations and demonstrate that it is mostly an artifact of the representation of microbial decomposition and its response during the spin-up procedure used by the models. The 6-fold Range in soil Carbon, once established, is maintained through the present and to 2100 almost unchanged even under a strong business-as-usual emissions scenario. By highlighting the role of the response of decomposition to spin-up in explaining why current CMIP5 soil Carbon stores vary widely, we identify the need to better constrain the outcome of this procedure as a means to reduce uncertainty in transient simulations.
Johann Ravaux - One of the best experts on this subject based on the ideXlab platform.
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High-temperature microstructures of ternary Co-30 wt.% Cr-based alloys over the [0–2.0 wt.%] Carbon Range
Journal of Alloys and Compounds, 2009Co-Authors: Patrice Berthod, P. Lemoine, Johann RavauxAbstract:Abstract The Co-30 wt.% Cr– x C system was experimentally explored from x = 0 to 2 wt.%, by considering the stable microstructures at 1000, 1100 and 1200 °C, and the intervals of fusion. The strengthening potential and the refractoriness of several alloys belonging to this family were specified. Such simple alloys are able to display simultaneously a high amount of chromium for limiting hot corrosion, solidus temperatures as high as 1300 °C and refractory carbides fractions that can reach 20% in volume. Natures and fractions of carbides, and solidus temperatures were in good agreements with thermodynamic calculations. Inversely the measured liquidus temperatures were significantly higher than the calculated ones. In addition, thermodynamic modeling allowed to better interpret the disappearance of carbides due to oxidation at high temperature.
Ryosuke O Suzuki - One of the best experts on this subject based on the ideXlab platform.
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Mathematical analysis of the solidification behavior of multi-component alloy steel based on the heat- and solute-transfer equations in the liquid–solid zone
International Journal of Heat and Mass Transfer, 2019Co-Authors: Toshio Fujimura, Kunimasa Takeshita, Ryosuke O SuzukiAbstract:Abstract An approximate analytical model has been developed to obtain simultaneous solutions for nonlinear solute- and heat-transfer equations for multi-component alloy steels; in this model, a linear relation between the solid fraction and the temperature in the mushy zone was assumed. This model predicts important parameters, such as the solidus temperature for the multi-component steel materials that have not been well confirmed by the reliable measurement in a real process. The predicted temperature, solidification constants, and effective partition ratios of solutes were in good agreement with both the reported measurements and generally accepted values. The predicted solidus temperatures were also in reasonable agreement with the reported zero ductile temperature of Fe–C–Mn steel and the thermo-analytically measured solidus temperatures of steels of various grades. The solutions were also in good agreement with those separately performed numerical thermal analysis. The model involves the solution for Fe-C binary alloy which is consistent with the Neumann’s solution in the low Carbon Range. Thus, this model provides approximate analytical solutions that can reduce the computational load, saving time and cost.
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Mathematical Analysis of the Solidification Behavior of Plain Steel Based on Solute- and Heat-Transfer Equations in the Liquid–Solid Zone
Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, 2018Co-Authors: Toshio Fujimura, Kunimasa Takeshita, Ryosuke O SuzukiAbstract:An analytical approximate solution to non-linear solute- and heat-transfer equations in the unsteady-state mushy zone of Fe-C plain steel has been obtained, assuming a linear relationship between the solid fraction and the temperature of the mushy zone. The heat transfer equations for both the solid and liquid zone along with the boundary conditions have been linked with the equations to solve the whole equations. The model predictions (e.g., the solidification constants and the effective partition ratio) agree with the generally accepted values and with a separately performed numerical analysis. The solidus temperature predicted by the model is in the intermediate Range of the reported formulas. The model and Neuman’s solution are consistent in the low Carbon Range. A conventional numerical heat analysis (i.e., an equivalent specific heat method using the solidus temperature predicted by the model) is consistent with the model predictions for Fe-C plain steels. The model presented herein simplifies the computations to solve the solute- and heat-transfer simultaneous equations while searching for a solidus temperature as a part of the solution. Thus, this model can reduce the complexity of analyses considering the heat- and solute-transfer phenomena in the mushy zone.
Jean-françois Exbrayat - One of the best experts on this subject based on the ideXlab platform.
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Response of microbial decomposition to spin-up explains CMIP5 soil Carbon Range until 2100
Geoscientific Model Development, 2014Co-Authors: Jean-françois Exbrayat, Andrew J. Pitman, Gab AbramowitzAbstract:Abstract. Soil Carbon storage simulated by the Coupled Model Intercomparison Project (CMIP5) models varies 6-fold for the present day. Here, we confirm earlier work showing that this Range already exists at the beginning of the CMIP5 historical simulations. We additionally show that this Range is largely determined by the response of microbial decomposition during each model's spin-up procedure from initialization to equilibration. The 6-fold Range in soil Carbon, once established prior to the beginning of the historical period (and prior to the beginning of a CMIP5 simulation), is then maintained through the present and to 2100 almost unchanged even under a strong business-as-usual emissions scenario. We therefore highlight that a commonly ignored part of CMIP5 analyses – the land surface state achieved through the spin-up procedure – can be important for determining future Carbon storage and land surface fluxes. We identify the need to better constrain the outcome of the spin-up procedure as an important step in reducing uncertainty in both projected soil Carbon and land surface fluxes in CMIP5 transient simulations.
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Response of microbial decomposition to spin-up explains CMIP5 soil Carbon Range until 2100
Geoscientific Model Development Discussions, 2014Co-Authors: Jean-françois Exbrayat, Andrew J. Pitman, Gab AbramowitzAbstract:Abstract. Soil Carbon storage simulated by the Coupled Model Intercomparison Project (CMIP5) models varies 6-fold for the present day. We show that this Range already exists at the beginning of the historical simulations and demonstrate that it is mostly an artifact of the representation of microbial decomposition and its response during the spin-up procedure used by the models. The 6-fold Range in soil Carbon, once established, is maintained through the present and to 2100 almost unchanged even under a strong business-as-usual emissions scenario. By highlighting the role of the response of decomposition to spin-up in explaining why current CMIP5 soil Carbon stores vary widely, we identify the need to better constrain the outcome of this procedure as a means to reduce uncertainty in transient simulations.
Patrice Berthod - One of the best experts on this subject based on the ideXlab platform.
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High-temperature microstructures of ternary Co-30 wt.% Cr-based alloys over the [0–2.0 wt.%] Carbon Range
Journal of Alloys and Compounds, 2009Co-Authors: Patrice Berthod, P. Lemoine, Johann RavauxAbstract:Abstract The Co-30 wt.% Cr– x C system was experimentally explored from x = 0 to 2 wt.%, by considering the stable microstructures at 1000, 1100 and 1200 °C, and the intervals of fusion. The strengthening potential and the refractoriness of several alloys belonging to this family were specified. Such simple alloys are able to display simultaneously a high amount of chromium for limiting hot corrosion, solidus temperatures as high as 1300 °C and refractory carbides fractions that can reach 20% in volume. Natures and fractions of carbides, and solidus temperatures were in good agreements with thermodynamic calculations. Inversely the measured liquidus temperatures were significantly higher than the calculated ones. In addition, thermodynamic modeling allowed to better interpret the disappearance of carbides due to oxidation at high temperature.