Models of the Trapped Radiation Environment. Volume 7 - Long Term Time Variations
Time variations of energetic electron and solar proton distributions in inner radiation belt
Imhof, W. L.↗
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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.
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Investigation of external refrigeration systems for long-term cryogenic storage
Evaluation of cryogenic refrigeration systems for space applications
Jensen, H. L.↗
Investigation of external refrigeration systems for long term cryogenic storage
Selection and optimization of space cryogenic storage tanks
Jensen, H. L.↗
A long term remote intragastric pH, temperature, motility and electrical activity monitoring system
Electronic instrumentation for monitoring intragastric pH, temperature, motility and electrical activity
Ballinger, W. F.↗
Perturbation theory in terms of reduced density matrices
Perturbation theory for reduced density matrices representable as functions of independent parameters
Harriman, J. E.↗
Prediction of long-term vacuum effects on mechanical properties of a heat shield material
Viking rocket heat shield material mechanical properties, examining time-temperature superposition with continuous stress relaxation data measured in vacuum
Greenwood, L. R.↗
Corrections for small values of the logarithm terms in the electrical conductivity of a fully ionized plasma
Correction factors for small values of logarithm of Debye length ratio to mean impact parameter in electrical conductivity of fully ionized plasma
Viegas, J. R.↗
Long-term drift of some noble- and refractory- metal thermocouples at 1600 K in air, argon, and vacuum
Thermal emf changes for noble and refractory metal thermocouples, determining drift in high temperature air, Ar and vacuum environments for long time periods
Glawe, G. E.↗
On explaining the F-region seasonal anomaly in terms of composition changes in the lower atmosphere
F region seasonal anomaly relationship with lower atmosphere composition changes, discussing effects of oxygen/nitrogen relative concentration on ionospheric and atmospheric parameters
Chandra, S.↗
Long-term tests of copper sulfide-cadmium sulfide thin-film solar cells under simulated orbital conditions
Copper sulfide-cadmium sulfide thin film solar cells under simulated orbital conditions, including thermal cycling, constant illumination and temperature effects
Clarke, D. R.↗
Lunar gravity analysis from long-term effects
Global lunar gravity field from weighted least squares analysis of Lunar Orbiters elements, deriving zonal and sectorial harmonics from libration data
Laing, P. A.↗
Long-term drift of thermocouples at 1600 K
Thermal electromotive-force changes for 30 commercially available noble- and refractory-metal thermocouples have been determined in air, argon, and vacuum, at 1600 K for exposures up to 10,000 hours. Investigation techniques can serve as guidelines for future studies of other thermocouple systems.
Glawe, G. E.↗
Numerical solution of potential flow problems in terms of flux components
Numerical determination of flux components in vapor flow considers split boundary conditions in both directions to form grid lines for flow continuity equations. Matrix of coefficients obtains direct solution for potential flow problem without iteration.
Vonrosenberg, D. U.↗
Dependence of defect introduction on temperature and resistivity and some long-term annealing effects
The effort reported here represents data of lithium properties in bulk-silicon samples before and after irradiation for analytical information required to characterize the interactions of lithium with radiation-induced defects in silicon. A model of the damage and recovery mechanisms in irradiated-lithium-containing solar cells is developed based on making measurements of the Hall coefficient and resistivity of samples irradiated by 1-MeV electrons. Experiments on bulk samples included Hall coefficient and resistivity measurements taken as a function of: (1) bombardment temperature, (2) resistivity, (3) fluence, (4) oxygen concentration, and (5) annealing time at temperatures from 300 to 373 K.
Brucker, G. J.↗
Long-term aging of elastomers: Chemical stress relaxation of fluorosilicone rubber and other studies
Aerospace applications of elastomers are considered, including: propellant binders, bladder materials for liquid propellant expulsion systems, and fuel tank sealants for high-speed aircraft. A comprehensive molecular theory for mechanical properties of these materials has been developed but has only been tested experimentally in cases where chemical degradation processes are excluded. Hence, a study is being conducted to ascertain the nature, extent, and rate of chemical changes that take place in some elastomers of interest. Chemical changes that may take place in the fluorosilicone elastomer, LS 420, which is regarded as a fuel and high-temperature-resistant rubber are investigated. The kinetic analysis of the chemical stress relaxation and gel permeation chromatography studies comprise the major portion of the report.
Kalfayan, S. H.↗
FORMAC integration program: A special applications package used in developing techniques of orbital decay and long term ephemeris prediction for satellites in earth orbit
The symbolic manipulation capabilities of the FORMAC (Formula Manipulation Compiler) language are employed to expand and analytically evaluate integrals. The program integration is effected by expanding the integral(s) into a series of subintegrals and then substituting a pre-derived and pre-coded solution for that particular subintegral. Derivation of the integral solutions necessary for precoding is included, as is a discussion of the FORMAC system limitations encountered in the programming effort.
Rowe, C. K.↗
Techniques of orbital decay and long-term ephemeris prediction for satellites in earth orbit
In the special perturbation method, Cowell and variation-of-parameters formulations of the motion equations are implemented and numerically integrated. Variations in the orbital elements due to drag are computed using the 1970 Jacchia atmospheric density model, which includes the effects of semiannual variations, diurnal bulge, solar activity, and geomagnetic activity. In the general perturbation method, two-variable asymptotic series and automated manipulation capabilities are used to obtain analytical solutions to the variation-of-parameters equations. Solutions are obtained considering the effect of oblateness only and the combined effects of oblateness and drag. These solutions are then numerically evaluated by means of a FORTRAN program in which an updating scheme is used to maintain accurate epoch values of the elements. The atmospheric density function is approximated by a Fourier series in true anomaly, and the 1970 Jacchia model is used to periodically update the Fourier coefficients. The accuracy of both methods is demonstrated by comparing computed orbital elements to actual elements over time spans of up to 8 days for the special perturbation method and up to 356 days for the general perturbation method.
Barry, B. F.↗
Long term temporal variations of the hard X-ray flux from the Centaurus region
The X-ray telescope aboard the third Orbiting Solar Observatory (OSO-3) observed the Centaurus region daily from 1967 October to 1968 February, and also for five days in 1968 June. A stable minimum flux of 0.33 + or - 0.03 photons (sq cm sec)/1 between 7.7 and 38 keV from a source around l = 305 deg is derived. Several single days show enhanced fluxes, and two extensive flaring episodes, one with a soft and the other a very hard spectrum, lasting at least ten days.
Schwartz, D. A.↗