The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Tatsumi Ishihara - One of the best experts on this subject based on the ideXlab platform.
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Effect of Co doping on oxygen Permeation in Sr3Ti2O7 with Ruddlesden-Popper structure
Solid State Ionics, 2011Co-Authors: Nuansaeng Sirikanda, Hiroshige Matsumoto, Tatsumi IshiharaAbstract:Abstract Effects of transition metal dopant to Ti site in Sr3Ti2-xMxO7 (M = Fe, Ga, Co) on the electrical conductivity and the oxygen Permeation property were investigated. Among the examined dopants, it was found that doping Co is the most effective for improving the electrical conductivity and the oxygen Permeation Rate. With increasing Co amount, electrical conductivity and oxygen Permeation Rate monotonically increased and the highest oxygen Permeation Rate is achieved at Sr3Ti0.8Co1.2O7 among the Co doped sample. On this composition, the oxygen Permeation Rate from air to He is achieved a value of 2.02 cc/min.cm2 at 1273 K.
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Oxygen Permeation Property in Nd Deficient Nd2NiO4 Mixed Oxide Doped with Cu and Ga
Electrochemical and Solid State Letters, 2010Co-Authors: Akihiro Kawahara, Tatsumi IshiharaAbstract:Oxygen Permeation property in Nd deficient Nd 2 NiO 4 was studied. The oxygen Permeation Rate increases with increasing Ga. Nd deficiency in Nd 2 NiO 4 is also useful for increasing the oxygen Permeation Rate. The improved oxygen Permeation Rate could be assigned to the increased amount of excess oxygen and stabilizing a tetragonal structure at a low temperature. The oxygen Permeation Rate of Nd 1.9 (Ni 0.75 Cu 0.25 ) 0.95 Ga 0.05 O 4 achieved a value of 3.6 cm 3 /min cm 2 from air to He at 1273 K with 0.5 mm thickness and this value belongs to the highest class in the reported oxygen Permeation Rate.
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high oxygen Permeation Rate in la0 6sr0 4ti0 3fe0 7o3 thin membrane on a porous support with multichannel structure for ch4 partial oxidation
Industrial & Engineering Chemistry Research, 2010Co-Authors: Akihiro Kawahara, Yousuke Takahashi, Yuji Hirano, Masayoshi Hirano, Tatsumi IshiharaAbstract:A preparation of La0.6Sr0.4Ti0.3Fe0.7O3 (LSTF) perovskite oxide on a support with a unique multichannel structure achieved a high oxygen Permeation Rate. A LSTF thin membrane with 60 μm thickness was successfully prepared on the multichannel support with 30% porosity. The oxygen Permeation Rate was much improved by using the multichannel structured support, as the permeated oxygen was removed rapidly. On the other hand, partial oxidation of CH4 into CO and H2 is dominant on the LSTF membrane. The oxygen Permeation Rate increased as the thickness of the membrane and the porous support decreased, and a value of 13.3 cm3/(min cm2) was achieved at 1273 K under a CH4 partial oxidation condition.
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Mixed conductivity and oxygen permeability of doped Pr2NiO4-based oxide
Solid State Ionics, 2006Co-Authors: Tatsumi Ishihara, Tetsuro Furuno, Oravan Sanguanruang, Shogo Miyoshi, Hiroshige MatsumotoAbstract:Abstract Pr 2 NiO 4 -based oxide was studied as a new mixed electronic and oxide ionic conductor for the oxygen Permeation membrane. It was found that Pr 2 NiO 4 doped with Cu and Fe for Ni site exhibits the relatively high oxygen Permeation Rate. Doping second cation to Ni site is effective for improving the oxygen Permeation Rate and the trivalent cation seems to be effective for increasing the oxygen Permeation Rate. Among the examined cation, the highest oxygen Permeation Rate was obtained by doping 5 mol% Fe. The oxygen Permeation Rate was also significantly affected by the surface catalyst and the highest oxygen Permeation Rate of 80 μmol·min − 1 ·cm − 2 at 1273 K was achieved by using La 0.1 Sr 0.9 Co 0.9 Fe 0.1 O 3 for the surface catalyst. Since the electrical conductivity slightly decreased with decreasing P O 2 and it dropped significantly at P O 2 = 10 − 19 atm, chemical stability of Pr 2 NiO 4 -based oxide seems to be reasonably high. Application of this new mixed conductor for the oxygen Permeation membrane under the CH 4 partial oxidation was also studied and it was confirmed that the oxygen Permeation Rate much improved under the CH 4 oxidation condition and this Pr 2 NiO 4 can be used for the oxygen Permeation membrane for the CH 4 partial oxidation.
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Mixed conductivity and oxygen permeability of doped Pr2NiO4-based oxide
Solid State Ionics, 2006Co-Authors: Tatsumi Ishihara, Tetsuro Furuno, Oravan Sanguanruang, Shogo Miyoshi, Hiroshige MatsumotoAbstract:Pr2NiO4-based oxide was studied as a new mixed electronic and oxide ionic conductor for the oxygen Permeation membrane. It was found that Pr2NiO4doped with Cu and Fe for Ni site exhibits the relatively high oxygen Permeation Rate. Doping second cation to Ni site is effective for improving the oxygen Permeation Rate and the trivalent cation seems to be effective for increasing the oxygen Permeation Rate. Among the examined cation, the highest oxygen Permeation Rate was obtained by doping 5 mol% Fe. The oxygen Permeation Rate was also significantly affected by the surface catalyst and the highest oxygen Permeation Rate of 80 μmol·min- 1·cm- 2at 1273 K was achieved by using La0.1Sr0.9Co0.9Fe0.1O3for the surface catalyst. Since the electrical conductivity slightly decreased with decreasing PO2and it dropped significantly at PO2= 10-19 atm, chemical stability of Pr2NiO4-based oxide seems to be reasonably high. Application of this new mixed conductor for the oxygen Permeation membrane under the CH4partial oxidation was also studied and it was confirmed that the oxygen Permeation Rate much improved under the CH4oxidation condition and this Pr2NiO4can be used for the oxygen Permeation membrane for the CH4partial oxidation. © 2006 Elsevier B.V. All rights reserved.
Yusaku Takita - One of the best experts on this subject based on the ideXlab platform.
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estimation of theoretical oxygen Permeation Rate through la sr ga fe o3 mixed conductor
Solid State Ionics, 2004Co-Authors: Tatsumi Ishihara, Tetsuro Furuno, Shinji Ishikawa, Chunying Yu, Masaki Ando, Hiroyasu Nishiguchi, Yusaku TakitaAbstract:Abstract Partial electronic and oxide ion conductivity in La 0.7 Sr 0.3 Ga 0.6 Fe 0.4 O 3 (LSGF) was investigated in this study by the ion blocking method. It was seen that LSGF stably exhibits the electronic hole conduction over wide oxygen partial pressure. The estimated oxide ion conductivity decreased with decreasing P O2 and this seem to be caused by decreasing amount of V O ¨ which is balanced with Fe valence number. The estimated transport number of oxide ion is reasonably agreed with those estimated by oxygen concentration cell. It was found that the theoretical oxygen Permeation Rate in LSGF is much larger than that of observed value. Therefore, it is expected that the oxygen Permeation Rate could be improved by increasing activity of surface catalyst.
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fe doped lagao3 perovskite oxide as an oxygen separating membrane for ch4 partial oxidation
Solid State Ionics, 2002Co-Authors: Tatsumi Ishihara, Hiroyasu Nishiguchi, Yuko Tsuruta, Toshitsune Todaka, Yusaku TakitaAbstract:Abstract Fe doped LaGaO3 based perovskite oxide was investigated in this study as an oxygen permeating membrane for CH4 partial oxidation. La0.7Sr0.3Ga0.6Fe0.4O3 exhibits a high oxygen Permeation Rate from air to He as high as 102 μmol/min cm2 (2.5 cm3-std/min·cm2) at 1273 K and 0.3 mm thickness. Application of LSGF membrane for CH4 partial oxidation was further studied. Since the PO2 difference became large, oxygen Permeation Rate drastically increased and it attained a value of 322 μmol/min cm2 (8 cm3/min cm2) at 1273 K and 0.5 mm thickness. Catalyst for CH4 partial oxidation has a great influence on oxygen Permeation Rate through membrane and it became clear that Ni and Ru are highly active for CH4 partial oxidation.
Alexander G. Venetsanos - One of the best experts on this subject based on the ideXlab platform.
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allowable hydrogen Permeation Rate from road vehicles
International Journal of Hydrogen Energy, 2011Co-Authors: P. Adams, B. Cariteau, Alain Bengaouer, Vladimir Molkov, Alexander G. VenetsanosAbstract:The paper presents an overview of the main results of the European Commission Network of Excellence “HySafe” activity to estimate an allowable hydrogen Permeation Rate for automotive legal requirements and standards. A slow, long term hydrogen release such as that due to Permeation from a vehicle into an inadequately ventilated enclosed structure is a potential risk associated with the use of hydrogen in automotive applications. Due to its small size hydrogen permeates through the containment materials found in compressed gaseous hydrogen storage systems and is an issue that requires consideration for containers with non-metallic (polymer) liners. Various Rates have been proposed in draft legal requirements and standards based on different scenarios and the assumption that permeated hydrogen disperses homogeneously in a garage like enclosure. This paper focuses on the development of a methodology to estimate an allowable upper limit for hydrogen Permeation in automotive applications, by investigating the behaviour of hydrogen when released through Permeation with a focus on European scenarios. The background to the activity is explained, worst credible scenarios are identified, a methodology proposed and a maximum hydrogen Permeation Rate from road vehicles into enclosed structures is estimated.
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Allowable hydrogen Permeation Rate from road vehicles
International Journal of Hydrogen Energy, 2011Co-Authors: P. Adams, B. Cariteau, Alain Bengaouer, Vladimir Molkov, Alexander G. VenetsanosAbstract:The paper presents an overview of the main results of the European Commission Network of Excellence "HySafe" activity to estimate an allowable hydrogen Permeation Rate for automotive legal requirements and standards. A slow, long term hydrogen release such as that due to Permeation from a vehicle into an inadequately ventilated enclosed structure is a potential risk associated with the use of hydrogen in automotive applications. Due to its small size hydrogen permeates through the containment materials found in compressed gaseous hydrogen storage systems and is an issue that requires consideration for containers with non-metallic (polymer) liners. Various Rates have been proposed in draft legal requirements and standards based on different scenarios and the assumption that permeated hydrogen disperses homogeneously in a garage like enclosure. This paper focuses on the development of a methodology to estimate an allowable upper limit for hydrogen Permeation in automotive applications, by investigating the behaviour of hydrogen when released through Permeation with a focus on European scenarios. The background to the activity is explained, worst credible scenarios are identified, a methodology proposed and a maximum hydrogen Permeation Rate from road vehicles into enclosed structures is estimated. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.
E. Tropsha - One of the best experts on this subject based on the ideXlab platform.
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layer by layer self assembly of alumosilicate polyelectrolyte composites mechanism of deposition crack resistance and perspectives for novel membrane materials
Chemistry of Materials, 1998Co-Authors: Nicholas A Kotov, S. Magonov, E. TropshaAbstract:The morphology and gas Permeation properties of montmorillonite−polyelectrolyte self-assembled multilayer systems have been investigated. Without any special pretreatment, a stable film of montmorillonite−polymer composite was assembled on a hydrophobic poly(ethyleneterephthalate) support by means of layer-by-layer deposition. All individual alumosilicate platelets were found to be oriented in parallel to the substRate, while their surface density strongly depended on the nature of the polyelectrolyte (charge and molecular weight). The organic−inorganic films were found to be very flexible and crack-resistant even under a considerable mechanical stress. This opened a possibility to preclude gas diffusion through defects and to design highly selective ultrathin membranes. A Permeation Rate of oxygen was found to decrease 6.6 times for ca. 200 nm montmorillonite/poly(diallyldimethylammonium) chloride film, while a Permeation Rate of aqueous vapors did not change at all. This effect was attributed to the dom...
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Layer-by-Layer Self-Assembly of Alumosilicate-Polyelectrolyte Composites: Mechanism of Deposition, Crack Resistance, and Perspectives for Novel Membrane Materials
Chemistry of Materials, 1998Co-Authors: Nicholas A Kotov, S. Magonov, E. TropshaAbstract:The morphology and gas Permeation properties of montmorillonite?polyelectrolyte self-assembled multilayer systems have been investigated. Without any special pretreatment, a stable film of montmorillonite?polymer composite was assembled on a hydrophobic poly(ethyleneterephthalate) support by means of layer-by-layer deposition. All individual alumosilicate platelets were found to be oriented in parallel to the substRate, while their surface density strongly depended on the nature of the polyelectrolyte (charge and molecular weight). The organic?inorganic films were found to be very flexible and crack-resistant even under a considerable mechanical stress. This opened a possibility to preclude gas diffusion through defects and to design highly selective ultrathin membranes. A Permeation Rate of oxygen was found to decrease 6.6 times for ca. 200 nm montmorillonite/poly(diallyldimethylammonium) chloride film, while a Permeation Rate of aqueous vapors did not change at all. This effect was attributed to the dominance of solution/adsorption Permeation mechanism over the Knudsen diffusion. This fact made the montmorillonite?polyelectrolyte multilayers stand out among other thin films for which the diffusion through defects was found to be the primary mechanism of gas Permeation. This finding demonstRated both practical and fundamental importance of hybrid thin films that combined the properties of both organic and inorganic materials.\nThe morphology and gas Permeation properties of montmorillonite?polyelectrolyte self-assembled multilayer systems have been investigated. Without any special pretreatment, a stable film of montmorillonite?polymer composite was assembled on a hydrophobic poly(ethyleneterephthalate) support by means of layer-by-layer deposition. All individual alumosilicate platelets were found to be oriented in parallel to the substRate, while their surface density strongly depended on the nature of the polyelectrolyte (charge and molecular weight). The organic?inorganic films were found to be very flexible and crack-resistant even under a considerable mechanical stress. This opened a possibility to preclude gas diffusion through defects and to design highly selective ultrathin membranes. A Permeation Rate of oxygen was found to decrease 6.6 times for ca. 200 nm montmorillonite/poly(diallyldimethylammonium) chloride film, while a Permeation Rate of aqueous vapors did not change at all. This effect was attributed to the dominance of solution/adsorption Permeation mechanism over the Knudsen diffusion. This fact made the montmorillonite?polyelectrolyte multilayers stand out among other thin films for which the diffusion through defects was found to be the primary mechanism of gas Permeation. This finding demonstRated both practical and fundamental importance of hybrid thin films that combined the properties of both organic and inorganic materials.
Hiroshige Matsumoto - One of the best experts on this subject based on the ideXlab platform.
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Effect of Co doping on oxygen Permeation in Sr3Ti2O7 with Ruddlesden-Popper structure
Solid State Ionics, 2011Co-Authors: Nuansaeng Sirikanda, Hiroshige Matsumoto, Tatsumi IshiharaAbstract:Abstract Effects of transition metal dopant to Ti site in Sr3Ti2-xMxO7 (M = Fe, Ga, Co) on the electrical conductivity and the oxygen Permeation property were investigated. Among the examined dopants, it was found that doping Co is the most effective for improving the electrical conductivity and the oxygen Permeation Rate. With increasing Co amount, electrical conductivity and oxygen Permeation Rate monotonically increased and the highest oxygen Permeation Rate is achieved at Sr3Ti0.8Co1.2O7 among the Co doped sample. On this composition, the oxygen Permeation Rate from air to He is achieved a value of 2.02 cc/min.cm2 at 1273 K.
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Mixed conductivity and oxygen permeability of doped Pr2NiO4-based oxide
Solid State Ionics, 2006Co-Authors: Tatsumi Ishihara, Tetsuro Furuno, Oravan Sanguanruang, Shogo Miyoshi, Hiroshige MatsumotoAbstract:Abstract Pr 2 NiO 4 -based oxide was studied as a new mixed electronic and oxide ionic conductor for the oxygen Permeation membrane. It was found that Pr 2 NiO 4 doped with Cu and Fe for Ni site exhibits the relatively high oxygen Permeation Rate. Doping second cation to Ni site is effective for improving the oxygen Permeation Rate and the trivalent cation seems to be effective for increasing the oxygen Permeation Rate. Among the examined cation, the highest oxygen Permeation Rate was obtained by doping 5 mol% Fe. The oxygen Permeation Rate was also significantly affected by the surface catalyst and the highest oxygen Permeation Rate of 80 μmol·min − 1 ·cm − 2 at 1273 K was achieved by using La 0.1 Sr 0.9 Co 0.9 Fe 0.1 O 3 for the surface catalyst. Since the electrical conductivity slightly decreased with decreasing P O 2 and it dropped significantly at P O 2 = 10 − 19 atm, chemical stability of Pr 2 NiO 4 -based oxide seems to be reasonably high. Application of this new mixed conductor for the oxygen Permeation membrane under the CH 4 partial oxidation was also studied and it was confirmed that the oxygen Permeation Rate much improved under the CH 4 oxidation condition and this Pr 2 NiO 4 can be used for the oxygen Permeation membrane for the CH 4 partial oxidation.
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Mixed conductivity and oxygen permeability of doped Pr2NiO4-based oxide
Solid State Ionics, 2006Co-Authors: Tatsumi Ishihara, Tetsuro Furuno, Oravan Sanguanruang, Shogo Miyoshi, Hiroshige MatsumotoAbstract:Pr2NiO4-based oxide was studied as a new mixed electronic and oxide ionic conductor for the oxygen Permeation membrane. It was found that Pr2NiO4doped with Cu and Fe for Ni site exhibits the relatively high oxygen Permeation Rate. Doping second cation to Ni site is effective for improving the oxygen Permeation Rate and the trivalent cation seems to be effective for increasing the oxygen Permeation Rate. Among the examined cation, the highest oxygen Permeation Rate was obtained by doping 5 mol% Fe. The oxygen Permeation Rate was also significantly affected by the surface catalyst and the highest oxygen Permeation Rate of 80 μmol·min- 1·cm- 2at 1273 K was achieved by using La0.1Sr0.9Co0.9Fe0.1O3for the surface catalyst. Since the electrical conductivity slightly decreased with decreasing PO2and it dropped significantly at PO2= 10-19 atm, chemical stability of Pr2NiO4-based oxide seems to be reasonably high. Application of this new mixed conductor for the oxygen Permeation membrane under the CH4partial oxidation was also studied and it was confirmed that the oxygen Permeation Rate much improved under the CH4oxidation condition and this Pr2NiO4can be used for the oxygen Permeation membrane for the CH4partial oxidation. © 2006 Elsevier B.V. All rights reserved.