336 research outputs found

    Development of advanced fuel cell system

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    Weight, life and performance characteristics optimization of hydrogen-oxygen fuel cell power systems were considered. A promising gold alloy cathode catalyst was identified and tested in a cell for 5,000 hours. The compatibility characteristics of candidate polymer structural materials were measured after exposure to electrolyte and water vapor for 8,000 hours. Lightweight cell designs were prepared and fabrication techniques to produce them were developed. Testing demonstrated that predicted performance was achieved. Lightweight components for passive product water removal and evaporative cooling of cells were demonstrated. Systems studies identified fuel cell powerplant concepts for meeting the requirements of advanced spacecraft

    The Coupled Magnetic Field Effects on the Microstructure Evolution and Magnetic Properties of As-Deposited and Post- Annealed Nano-Scaled Co-Based Films — Part II

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    Superimposed external magnetic fields during electrodeposition process offers the possibility to tailor the microstructure and properties of the obtained films in a very efficient, contactless, and easily controllable way, which is caused by so-called magnetohydrodynamic (MHD) effect. On the other hand, the non-equilibrium state of as-electrodeposited nanocrystalline films provides a strong thermodynamic potential for microstructural transformation. This means that the beneficial effect of magneto-electrodeposition on a nanocrystalline film can be completely consumed by thermal exposure at a relatively low temperature. Magnetic field annealing has been confirmed to be useful for tailoring the microstructure of as-deposited nanocrystalline films for their widespread uses
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