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D M J Smeulders - One of the best experts on this subject based on the ideXlab platform.
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mass diffusivity and thermal conductivity estimation of chloride based salt hydrates for thermo chemical heat storage a molecular dynamics study using the reactive force field
International Journal of Heat and Mass Transfer, 2020Co-Authors: A Amar D Pathak, Koen Heijmans, S Silvia V Nedea, Adri C T Van Duin, H A Zondag, Camilo C M Rindt, D M J SmeuldersAbstract:Abstract Mixed salt hydrates recently proved to be promising potential candidates for long-term heat storage. Among them, MgCl2 and CaCl2 are two widely used salts able to store energy via a reversible hydration/dehydration cycle. The hydration/dehydration of the salts is influenced by thermal and structural material characteristics. To be able to study the Complete Behavior of the hydration/dehydration cycle including material transformation and degradation, molecular scale modeling is essential. Reliable reactive force fields transferable to different levels of system hydration/dehydration are needed in order to reproduce the material characteristics. Two new transferable force field for MgCl2 and CaCl2 are proposed and used to investigate the heat and mass transport for the salt hydrates. Using these new force fields, the diffusion coefficient of water through MgCl2.nH2O (n =1 to 6) is found to be in the range 10 − 11 to 10 − 9 m2/s and comparable to experimental values. The surface effects were found to play a negligible role for MgCl2.6H2O while for the other hydrates surface effects play a noticeable role in the dehydration reaction. The thermal conductivities showed an increase with hydration state from 0.3-0.9 W/mK for all MgCl2 hydrates. A strong anisotropy for thermal conduction for MgCl2.6H2O is observed. The thermal conductivities of these two salts and their hydrates show that mixing will not impair the thermal conductivity of the storage system but it will have a strong effect on the competing hydrolysis reaction.
Adri C T Van Duin - One of the best experts on this subject based on the ideXlab platform.
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mass diffusivity and thermal conductivity estimation of chloride based salt hydrates for thermo chemical heat storage a molecular dynamics study using the reactive force field
International Journal of Heat and Mass Transfer, 2020Co-Authors: A Amar D Pathak, Koen Heijmans, S Silvia V Nedea, Adri C T Van Duin, H A Zondag, Camilo C M Rindt, D M J SmeuldersAbstract:Abstract Mixed salt hydrates recently proved to be promising potential candidates for long-term heat storage. Among them, MgCl2 and CaCl2 are two widely used salts able to store energy via a reversible hydration/dehydration cycle. The hydration/dehydration of the salts is influenced by thermal and structural material characteristics. To be able to study the Complete Behavior of the hydration/dehydration cycle including material transformation and degradation, molecular scale modeling is essential. Reliable reactive force fields transferable to different levels of system hydration/dehydration are needed in order to reproduce the material characteristics. Two new transferable force field for MgCl2 and CaCl2 are proposed and used to investigate the heat and mass transport for the salt hydrates. Using these new force fields, the diffusion coefficient of water through MgCl2.nH2O (n =1 to 6) is found to be in the range 10 − 11 to 10 − 9 m2/s and comparable to experimental values. The surface effects were found to play a negligible role for MgCl2.6H2O while for the other hydrates surface effects play a noticeable role in the dehydration reaction. The thermal conductivities showed an increase with hydration state from 0.3-0.9 W/mK for all MgCl2 hydrates. A strong anisotropy for thermal conduction for MgCl2.6H2O is observed. The thermal conductivities of these two salts and their hydrates show that mixing will not impair the thermal conductivity of the storage system but it will have a strong effect on the competing hydrolysis reaction.
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Mass diffusivity and thermal conductivity estimation of chloride-based salt hydrates for thermo-chemical heat storage:a molecular dynamics study using the reactive force field.
'Elsevier BV', 2020Co-Authors: Pathak, Ad Amar, Adri C T Van Duin, Heijmans K, Nedea, Sv Silvia, Zondag, Ha Herbert, Rindt, Ccm Camilo, Smeulders, Dmj DavidAbstract:\u3cp\u3eMixed salt hydrates recently proved to be promising potential candidates for long-term heat storage. Among them, MgCl\u3csub\u3e2\u3c/sub\u3e and CaCl\u3csub\u3e2\u3c/sub\u3e are two widely used salts able to store energy via a reversible hydration/dehydration cycle. The hydration/dehydration of the salts is influenced by thermal and structural material characteristics. To be able to study the Complete Behavior of the hydration/dehydration cycle including material transformation and degradation, molecular scale modeling is essential. Reliable reactive force fields transferable to different levels of system hydration/dehydration are needed in order to reproduce the material characteristics. Two new transferable force field for MgCl\u3csub\u3e2\u3c/sub\u3e and CaCl\u3csub\u3e2\u3c/sub\u3e are proposed and used to investigate the heat and mass transport for the salt hydrates. Using these new force fields, the diffusion coefficient of water through MgCl\u3csub\u3e2\u3c/sub\u3e.nH\u3csub\u3e2\u3c/sub\u3eO (n =1 to 6) is found to be in the range 10\u3csup\u3e−11\u3c/sup\u3e to 10\u3csup\u3e−9\u3c/sup\u3e m\u3csup\u3e2\u3c/sup\u3e/s and comparable to experimental values. The surface effects were found to play a negligible role for MgCl\u3csub\u3e2\u3c/sub\u3e.6H\u3csub\u3e2\u3c/sub\u3eO while for the other hydrates surface effects play a noticeable role in the dehydration reaction. The thermal conductivities showed an increase with hydration state from 0.3-0.9 W/mK for all MgCl\u3csub\u3e2\u3c/sub\u3e hydrates. A strong anisotropy for thermal conduction for MgCl\u3csub\u3e2\u3c/sub\u3e.6H\u3csub\u3e2\u3c/sub\u3eO is observed. The thermal conductivities of these two salts and their hydrates show that mixing will not impair the thermal conductivity of the storage system but it will have a strong effect on the competing hydrolysis reaction.\u3c/p\u3
G R Myneni - One of the best experts on this subject based on the ideXlab platform.
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magneto thermal conductivity of superconducting nb with intermediate level of impurity
Superconductor Science and Technology, 2012Co-Authors: L Sharath S Chandra, M K Chattopadhyay, S B Roy, V C Sahni, G R MyneniAbstract:Niobium materials with intermediate purity level are used for fabrication of superconducting radio frequency cavities (SCRF), and thermal conductivity is an important parameter influencing the performance of such SCRF cavities. We report here the temperature and magnetic field dependence of thermal conductivity κ for superconducting niobium (Nb) samples, for which the electron mean free path le, the phonon mean free path lg, and the vortex core diameter 2rC are of the same order of magnitude. The measured thermal conductivity is analyzed using the effective gap model (developed for le ≫ 2rC (Dubeck et al 1963 Phys. Rev. Lett. 10 98)) and the normal core model (developed for le ≪ 2rC (Ward and Dew-Hughes 1970 J. Phys. C: Solid St. Phys. 3 2245)). However, it is found that the effective gap model is not suitable for low temperatures when le ∼ 2rC. The normal core model, on the other hand, is able to describe κ(T,H) over the entire temperature range except in the field regime between HC1 and HC2 i.e. in the mixed state. It is shown that to understand the Complete Behavior of κ in the mixed state, the scattering of quasi-particles from the vortex cores and the intervortex quasi-particle tunneling are to be invoked. The quasi-particle scattering from vortices for the present system is understood in terms of the framework of Sergeenkov and Ausloos (1995 Phys. Rev. B 52 3614) extending their approach to the case of Nb. The intervortex tunneling is understood within the framework of Schmidbauer et al (1970 Z. Phys. 240 30). Analysis of the field dependence of thermal conductivity shows that while the quasi-particle scattering from vortices dominates in the low fields, the intervortex quasi-particle tunneling dominates in high fields. Analysis of the temperature dependence of thermal conductivity shows that while the quasi-particle scattering is dominant at low temperatures, the intervortex quasi-particle tunneling is dominant at high temperatures.
Smeulders, Dmj David - One of the best experts on this subject based on the ideXlab platform.
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Mass diffusivity and thermal conductivity estimation of chloride-based salt hydrates for thermo-chemical heat storage:a molecular dynamics study using the reactive force field.
'Elsevier BV', 2020Co-Authors: Pathak, Ad Amar, Adri C T Van Duin, Heijmans K, Nedea, Sv Silvia, Zondag, Ha Herbert, Rindt, Ccm Camilo, Smeulders, Dmj DavidAbstract:\u3cp\u3eMixed salt hydrates recently proved to be promising potential candidates for long-term heat storage. Among them, MgCl\u3csub\u3e2\u3c/sub\u3e and CaCl\u3csub\u3e2\u3c/sub\u3e are two widely used salts able to store energy via a reversible hydration/dehydration cycle. The hydration/dehydration of the salts is influenced by thermal and structural material characteristics. To be able to study the Complete Behavior of the hydration/dehydration cycle including material transformation and degradation, molecular scale modeling is essential. Reliable reactive force fields transferable to different levels of system hydration/dehydration are needed in order to reproduce the material characteristics. Two new transferable force field for MgCl\u3csub\u3e2\u3c/sub\u3e and CaCl\u3csub\u3e2\u3c/sub\u3e are proposed and used to investigate the heat and mass transport for the salt hydrates. Using these new force fields, the diffusion coefficient of water through MgCl\u3csub\u3e2\u3c/sub\u3e.nH\u3csub\u3e2\u3c/sub\u3eO (n =1 to 6) is found to be in the range 10\u3csup\u3e−11\u3c/sup\u3e to 10\u3csup\u3e−9\u3c/sup\u3e m\u3csup\u3e2\u3c/sup\u3e/s and comparable to experimental values. The surface effects were found to play a negligible role for MgCl\u3csub\u3e2\u3c/sub\u3e.6H\u3csub\u3e2\u3c/sub\u3eO while for the other hydrates surface effects play a noticeable role in the dehydration reaction. The thermal conductivities showed an increase with hydration state from 0.3-0.9 W/mK for all MgCl\u3csub\u3e2\u3c/sub\u3e hydrates. A strong anisotropy for thermal conduction for MgCl\u3csub\u3e2\u3c/sub\u3e.6H\u3csub\u3e2\u3c/sub\u3eO is observed. The thermal conductivities of these two salts and their hydrates show that mixing will not impair the thermal conductivity of the storage system but it will have a strong effect on the competing hydrolysis reaction.\u3c/p\u3
A Amar D Pathak - One of the best experts on this subject based on the ideXlab platform.
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mass diffusivity and thermal conductivity estimation of chloride based salt hydrates for thermo chemical heat storage a molecular dynamics study using the reactive force field
International Journal of Heat and Mass Transfer, 2020Co-Authors: A Amar D Pathak, Koen Heijmans, S Silvia V Nedea, Adri C T Van Duin, H A Zondag, Camilo C M Rindt, D M J SmeuldersAbstract:Abstract Mixed salt hydrates recently proved to be promising potential candidates for long-term heat storage. Among them, MgCl2 and CaCl2 are two widely used salts able to store energy via a reversible hydration/dehydration cycle. The hydration/dehydration of the salts is influenced by thermal and structural material characteristics. To be able to study the Complete Behavior of the hydration/dehydration cycle including material transformation and degradation, molecular scale modeling is essential. Reliable reactive force fields transferable to different levels of system hydration/dehydration are needed in order to reproduce the material characteristics. Two new transferable force field for MgCl2 and CaCl2 are proposed and used to investigate the heat and mass transport for the salt hydrates. Using these new force fields, the diffusion coefficient of water through MgCl2.nH2O (n =1 to 6) is found to be in the range 10 − 11 to 10 − 9 m2/s and comparable to experimental values. The surface effects were found to play a negligible role for MgCl2.6H2O while for the other hydrates surface effects play a noticeable role in the dehydration reaction. The thermal conductivities showed an increase with hydration state from 0.3-0.9 W/mK for all MgCl2 hydrates. A strong anisotropy for thermal conduction for MgCl2.6H2O is observed. The thermal conductivities of these two salts and their hydrates show that mixing will not impair the thermal conductivity of the storage system but it will have a strong effect on the competing hydrolysis reaction.