Resonances in proton-hydrogen and positron- hydrogen scattering.
Resonances in proton hydrogen and positron hydrogen scattering predicted at energies just below excitation thresholds
SEARCH · Search NASA
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Resonances in proton hydrogen and positron hydrogen scattering predicted at energies just below excitation thresholds
Vacuum test facilities are required for high speed cryopumping of gaseous hydrogen at low pressures. One method involves the catalytic oxidation of hydrogen and condensation of the resulting water on a liquid nitrogen-cooled surface.
Dynamics of water rejection from hydrogen-oxygen fuel cell to hydrogen stream
Determining fugacities of hydrogen in hydrogen and propane mixtures using semipermeable membrane
Simulated hydrogen leakage in electrolytic hydrogen-oxygen fuel cells
Hydrogen gas pressure requirements during pressurization and transfer of liquid hydrogen from spherical tanks
Absorption of hydrogen by palladium and electrical resistivity of hydrogen-palladium system
Multiple velocity dispersion in normal hydrogen and normal hydrogen-helium mixtures at room temperature using ultrasonic interferometer
Hydrogen-hydrogen excitation collisions by impact parameter treatment, investigating rotation coupling influence in four state cross sections approximation
Hydrogen-hydrogen double excitation collision cross sections computed by impact parameter method, using Born and two state approximations
Quadrupole coupling between single and double excitation channels in hydrogen-hydrogen collisions found ineffective due to energy defect between channels
Flux, energy spectra, and pitch angle distributions of precipitated low energy hydrogen and electrons from Nike-Tomahawk auroral hydrogen experiment
Ab initio calculations on trajectories and nonadiabatic transitions in reactions of hydrogen atomic ions with hydrogen molecules
A one-megawatt wind energy source is assumed that uses half of its output to serve customers as electricity, and stores the other half by conversion to hydrogen, to liquid hydrogen, to stored LH2, and back to electricity. Energy costs and capital costs of the conversions escalate unit costs to 12.9 cents per kilowatt hour. High conversion costs can be reduced by using Mg2NiH4 and FeTiH2 storage, or by using a 100- or 1000 megawatt system.
Rate constants for rotational excitation of hydrogen molecules by collisions with hydrogen atoms have been obtained from quantum-mechanical calculations for kinetic temperatures between 100 and 5000 K. These calculations involve the rigid-rotator approximation, but other possible sources of error should be small. The calculations indicate that the early values of Nishimura are larger than accurate rigid-rotator values by about a factor of 20 or more.
Successful IUE observations of the equatorial sunlit atmosphere of Jupiter and Saturn have been obtained. Spectra containing atomic and molecular hydrogen and solar reflection continuum emissions have been analyzed, with the purpose of determining the long term temporal behavior of the electroglow process. Quantitative estimates have been established for the first time using a model analysis of the short wavelength region of the spectrum. Both systems show varying degrees of long term variability in hydrogen emission rate, but the time scale is too short to determine whether there is a dependence on solar cycle activity. As part of the emission modeling program, a preliminary point source spreading function for the IUE SWP instrument has been established, suggesting a wavelength dependence in spectral line width different from previous analyses. Further IUE observations are planned for both Jupiter and Saturn.
Binary platinum alloys are being developed as hydrogen electrocatalysts for use in a hydrogen bromide battery system. These alloys were varied in terms of alloy component mole ratio and heat treatment temperature. Electrocatalyst evaluation, performed in the absence and presence of bromide ion, includes floating half cell polarization studies, electrochemical surface area measurements, X ray diffraction analysis, scanning electron microscopy analysis and corrosion measurements. Results obtained to date indicate a platinum rich alloy has the best tolerance to bromide ion poisoning.
Fully nonadiabatic g-mode pulsation calculations have been obtained for evolutionary models of planetary nebula nuclei (PNN) with active hydrogen-burning shells. Expressions have been developed for the phase delays which can develop between the temperature variations and the abundance variations of agents in the CN cycle. G-mode instabilities are noted that are driven by the epsilon mechanism at the position of the nuclear burning shells in standard PNN models. The results indicate that the central stars do not retain sufficient hydrogen to support nuclear burning following ejection of the planetary nebula.