The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Armin Feldhoff - One of the best experts on this subject based on the ideXlab platform.
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phase stability and permeation behavior of a dead end ba 0 5 sr 0 5 co 0 8 fe 0 2 o 3 delta tube membrane in high purity Oxygen Production
Chemistry of Materials, 2011Co-Authors: Fangyi Liang, Heqing Jiang, Huixia Luo, Jurgen Caro, Armin FeldhoffAbstract:Phase stability and Oxygen permeation behavior of Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) dead-end tube membranes were investigated in long-term Oxygen Production at 950 and 750 °C. At 950 °C, the BSCF tube membranes exhibit good long-term phase stability and a stable Oxygen permeation flux. However, at the intermediate temperature of 750 °C, both the Oxygen permeation flux and the Oxygen purity decrease continuously. This behavior is related to the formation of two secondary phases that are a hexagonal perovskite, Ba0.5±xSr0.5±xCoO3−δ, and a trigonal mixed oxide, Ba1–xSrxCo2–yFeyO5, that evolved in the ceramic membrane made of cubic BSCF perovskite during the dynamic flow of Oxygen through it. Tensile stress as a result of phase formation causes the development of cracks in the membrane, which spoil the purity of the permeated Oxygen. The partial degradation of cubic BSCF perovskite in the intermediate temperature range (750 °C) was more pronounced under the strongly oxidizing conditions on the Oxygen supply (fe...
Olivier De Weck - One of the best experts on this subject based on the ideXlab platform.
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Architecture Modeling of In-Situ Oxygen Production and its Impacts on Lunar Campaigns
AIAA SPACE 2008 Conference & Exposition, 2008Co-Authors: A Chepko, Olivier De Weck, Diane Linne, Edgardo Santiago-maldonado, William A. CrossleyAbstract:In-situ lunar Oxygen Production has the potential to reduce the cargo mass launched from Earth necessary to sustain a lunar base. As research and development in lunar Oxygen Production continue, modeling tools are being used to help characterize the many possible system architectures and guide decisions for future plant designs. Using the previously built NASA In-Situ Resource Utilization (ISRU) System Model, an optimization tool was developed to facilitate exploration of the design space of the different system architectures represented in the model. For each architecture, an optimization of the continuous design space is performed using a gradient-based search. In instances when the gradient-based search cannot converge, the tool changes to simulated annealing, a heuristic method. Nine primary lunar Oxygen Production system architectures were optimized to minimize system mass for Oxygen Production levels from 500 kg/yr to 6000 kg/yr. Good designs minimized mass and maximized produced Oxygen with system masses in the range of 100 kg to 700 kg. Preliminary results show that two particular architectures populate the Pareto-optimal front of best designs for most Production levels, making them attractive for further investigation. An economy of scale of .837 was found using a power law regression, indicating that some economy of scale exists (values less than one have economy of scale) and that launching fewer, higher-capacity plants will be less massive overall than many small-capacity plants to achieve the same total Production level. A simplified comparison of lunar-produced Oxygen for crew breathing supply and ECLSS (environmental control and life support systems) technologies was performed with a space logistics planning tool, SpaceNet. For all but the most advanced ECLSS technologies, use of in-situ Oxygen over a 10-year campaign resulted in more than 12,000 kg of consumables cargo launch mass savings.
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Architecture Modeling of In-Situ Oxygen Production and its Impacts on Lunar Campaigns
AIAA SPACE 2008 Conference & Exposition, 2008Co-Authors: A Chepko, Olivier De WeckAbstract:In-situ lunar Oxygen Production has the potential to reduce the cargo mass launched from Earth necessary to sustain a lunar base. As research and development in lunar Oxygen Production continue, modeling tools are being used to help characterize the many possible system architectures and guide decisions for future plant designs. Using the previously built NASA In-Situ Resource Utilization (ISRU) System Model, an optimization tool was developed to facilitate exploration of the design space of the different system architectures represented in the model. For each architecture, an optimization of the continuous design space is performed using a gradient-based search. In instances when the gradient-based search cannot converge, the tool changes to simulated annealing, a heuristic method. Nine primary lunar Oxygen Production system architectures were optimized to minimize system mass for Oxygen Production levels from 500 kg/yr to 6000 kg/yr. Good designs minimized mass and maximized produced Oxygen with system masses in the range of 100 kg to 700 kg. Preliminary results show that two particular architectures populate the Pareto-optimal front of best designs for most Production levels, making them attractive for further investigation. An economy of scale of .837 was found using a power law regression, indicating that some economy of scale exists (values less than one have economy of scale) and that launching fewer, higher-capacity plants will be less massive overall than many small-capacity plants to achieve the same total Production level. A simplified comparison of lunar-produced Oxygen for crew breathing supply and ECLSS (environmental control and life support systems) technologies was performed with a space logistics planning tool, SpaceNet. For all but the most advanced ECLSS technologies, use of in-situ Oxygen over a 10-year campaign resulted in more than 12,000 kg of consumables cargo launch mass savings. Nomenclature = economy of scale C = investment cost
A Chepko - One of the best experts on this subject based on the ideXlab platform.
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Architecture Modeling of In-Situ Oxygen Production and its Impacts on Lunar Campaigns
AIAA SPACE 2008 Conference & Exposition, 2008Co-Authors: A Chepko, Olivier De Weck, Diane Linne, Edgardo Santiago-maldonado, William A. CrossleyAbstract:In-situ lunar Oxygen Production has the potential to reduce the cargo mass launched from Earth necessary to sustain a lunar base. As research and development in lunar Oxygen Production continue, modeling tools are being used to help characterize the many possible system architectures and guide decisions for future plant designs. Using the previously built NASA In-Situ Resource Utilization (ISRU) System Model, an optimization tool was developed to facilitate exploration of the design space of the different system architectures represented in the model. For each architecture, an optimization of the continuous design space is performed using a gradient-based search. In instances when the gradient-based search cannot converge, the tool changes to simulated annealing, a heuristic method. Nine primary lunar Oxygen Production system architectures were optimized to minimize system mass for Oxygen Production levels from 500 kg/yr to 6000 kg/yr. Good designs minimized mass and maximized produced Oxygen with system masses in the range of 100 kg to 700 kg. Preliminary results show that two particular architectures populate the Pareto-optimal front of best designs for most Production levels, making them attractive for further investigation. An economy of scale of .837 was found using a power law regression, indicating that some economy of scale exists (values less than one have economy of scale) and that launching fewer, higher-capacity plants will be less massive overall than many small-capacity plants to achieve the same total Production level. A simplified comparison of lunar-produced Oxygen for crew breathing supply and ECLSS (environmental control and life support systems) technologies was performed with a space logistics planning tool, SpaceNet. For all but the most advanced ECLSS technologies, use of in-situ Oxygen over a 10-year campaign resulted in more than 12,000 kg of consumables cargo launch mass savings.
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Architecture Modeling of In-Situ Oxygen Production and its Impacts on Lunar Campaigns
AIAA SPACE 2008 Conference & Exposition, 2008Co-Authors: A Chepko, Olivier De WeckAbstract:In-situ lunar Oxygen Production has the potential to reduce the cargo mass launched from Earth necessary to sustain a lunar base. As research and development in lunar Oxygen Production continue, modeling tools are being used to help characterize the many possible system architectures and guide decisions for future plant designs. Using the previously built NASA In-Situ Resource Utilization (ISRU) System Model, an optimization tool was developed to facilitate exploration of the design space of the different system architectures represented in the model. For each architecture, an optimization of the continuous design space is performed using a gradient-based search. In instances when the gradient-based search cannot converge, the tool changes to simulated annealing, a heuristic method. Nine primary lunar Oxygen Production system architectures were optimized to minimize system mass for Oxygen Production levels from 500 kg/yr to 6000 kg/yr. Good designs minimized mass and maximized produced Oxygen with system masses in the range of 100 kg to 700 kg. Preliminary results show that two particular architectures populate the Pareto-optimal front of best designs for most Production levels, making them attractive for further investigation. An economy of scale of .837 was found using a power law regression, indicating that some economy of scale exists (values less than one have economy of scale) and that launching fewer, higher-capacity plants will be less massive overall than many small-capacity plants to achieve the same total Production level. A simplified comparison of lunar-produced Oxygen for crew breathing supply and ECLSS (environmental control and life support systems) technologies was performed with a space logistics planning tool, SpaceNet. For all but the most advanced ECLSS technologies, use of in-situ Oxygen over a 10-year campaign resulted in more than 12,000 kg of consumables cargo launch mass savings. Nomenclature = economy of scale C = investment cost
Fangyi Liang - One of the best experts on this subject based on the ideXlab platform.
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phase stability and permeation behavior of a dead end ba 0 5 sr 0 5 co 0 8 fe 0 2 o 3 delta tube membrane in high purity Oxygen Production
Chemistry of Materials, 2011Co-Authors: Fangyi Liang, Heqing Jiang, Huixia Luo, Jurgen Caro, Armin FeldhoffAbstract:Phase stability and Oxygen permeation behavior of Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) dead-end tube membranes were investigated in long-term Oxygen Production at 950 and 750 °C. At 950 °C, the BSCF tube membranes exhibit good long-term phase stability and a stable Oxygen permeation flux. However, at the intermediate temperature of 750 °C, both the Oxygen permeation flux and the Oxygen purity decrease continuously. This behavior is related to the formation of two secondary phases that are a hexagonal perovskite, Ba0.5±xSr0.5±xCoO3−δ, and a trigonal mixed oxide, Ba1–xSrxCo2–yFeyO5, that evolved in the ceramic membrane made of cubic BSCF perovskite during the dynamic flow of Oxygen through it. Tensile stress as a result of phase formation causes the development of cracks in the membrane, which spoil the purity of the permeated Oxygen. The partial degradation of cubic BSCF perovskite in the intermediate temperature range (750 °C) was more pronounced under the strongly oxidizing conditions on the Oxygen supply (fe...
Elias Greenbaum - One of the best experts on this subject based on the ideXlab platform.
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Photosynthetic Hydrogen and Oxygen Production by Green Algae
1999Co-Authors: Elias GreenbaumAbstract:Photosynthesis research at Oak Ridge National Laboratory is focused on hydrogen and Oxygen Production by green algae in the context of its potential as a renewable fuel and chemical feed stock. Beginning with its discovery by Gaffron and Rubin in 1942, motivated by curiosity-driven laboratory research, studies were initiated in the early 1970s that focused on photosynthetic hydrogen Production from an applied perspective. From a scientific and technical point of view, current research is focused on optimizing net thermodynamic conversion efficiencies represented by the Gibbs Free Energy of molecular hydrogen. The key research questions of maximizing hydrogen and Oxygen Production by light-activated water splitting in green algae are: (1) removing the Oxygen sensitivity of algal hydrogenases; (2) linearizing the light saturation curves of hotosynthesis throughout the entire range of terrestrial solar irradiance-including the role of bicarbonate and carbon dioxide in optimization of photosynthetic electron transpor;t and (3) constructing real-world bioreactors, including the generation of hydrogen and Oxygen against workable back pressures of the photoproduced gases.
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Photosynthetic hydrogen and Oxygen Production by green algae
BioHydrogen, 1998Co-Authors: Elias GreenbaumAbstract:An overview of photosynthetic hydrogen and Oxygen Production by green algae in the context of its potential as a renewable chemical feed stock and energy carrier is presented. Beginning with its discovery by Gaffron and Rubin in 1942, motivated by curiosity-driven laboratory research, studies were initiated in the early 1970s that focused on photosynthetic hydrogen Production from an applied perspective. From a scientific and technical point of view, current research is focused on optimizing net thermodynamic conversion efficiencies represented by the Gibbs Free Energy of molecular hydrogen. The key research questions of maximizing hydrogen and Oxygen Production by light-activated water splitting in green algae are (1) removing the Oxygen sensitivity of algal hydrogenases; (2) linearizing the light saturation curves of photosynthesis throughout the entire range of terrestrial solar irradiance--including the role of bicarbonate and carbon dioxide in optimization of photosynthetic electron transport and (3) the minimum number of light reactions that are required to split water to elemental hydrogen and Oxygen. Each of these research topics is being actively addressed by the photobiological hydrogen research community.
