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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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At least 1,351 records · Page 75
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NASA NTRS1972

Interferometer observations of Uranus, Neptune, and Pluto at wavelengths of 11.1 and 3.7 centimeters.

Visibility observations of Uranus at 8.085 GHz fit a uniform circular disk with a diameter of 3.8 (plus or minus 0.2) sec. The disk temperature of Uranus and Neptune are, respectively 189 (plus or minus 7) K and 190 (plus or minus 20) K at 8.085 GHz, and 195 (plus or minus 30) K and 201 (plus or minus 40) K at 2.695 GHz, in agreement with previous results that the microwave temperatures are higher than those expected for blackbodies in equilibrium with solar radiation. The 8.085-GHz observations yield an upper limit of 162 K for the disk temperature of Pluto.

Webster, W. J., Jr.↗
NASA NTRS1972

Polarization of solar active regions at 9.5 mm wavelength.

A study of the circular polarization structure of solar active regions has been made from data obtained at 9.5 mm. All important active regions observed at 9.5 mm are bipolar in nature, the degree of polarization is about the same for both right and left circular components, and it ranges up to about 4%. These oppositely polarized components correspond with the Mt. Wilson magnetic regions of opposite polarity; the line of zero polarization delineates clearly the neutral line between the regions of opposite polarity on magnetograms. Unipolar regions in magnetograms also show up as unipolar regions at 9.5 mm. Magnetic fields as low as 5-10 G on magnetograms manifest as distinctly polarized regions on 9.5 mm maps.

Kundu, M. R.↗
NASA NTRS1972

Quantitative simultaneous multi-element microprobe analysis using combined wavelength and energy dispersive systems

A combined WDS-EDS system obviates the severe X-ray peak overlap problems encountered with Na, Mg, Al and Si common to pure EDS systems. By application of easily measured empirical correction factors for pulse pile-up and peak overlaps which are normally observed in the analysis of silicate minerals, the accuracy of analysis is comparable with that expected for WDS electron microprobe analyses. The continuum backgrounds are subtracted for the spectra by a spline fitting technique based on integrated intensities between the peaks. The preprocessed data are then reduced to chemical analyses by existing data reduction programs.

Walter, L. S.↗
NASA NTRS1972

The interstellar line spectra of zeta Ophiuchi and zeta Persei and their relation to the short wavelength microwave background radiation

Thirty-one high dispersion Coude spectrograms of zeta Ophiuchi and seven of zeta Persei were numerically synthesized to produce high resolution, low noise spectra in the interval 3650 A to 4350 that yield data on atomic and molecular absorption in well-defined regions of the interstellar medium. The detection threshold is improved by as much as a factor 5 over single plates. Several interstellar lines were discovered in the zeta Oph - 15km/sec cloud and the zeta Per + 13 km/sec cloud.

Bortolot, V. J., Jr.↗
NASA NTRS1973

Solar flare produced pulsations in meter and X-ray wavelengths

The mechanism responsible for the modulation of synchrotron radiation in the meter wave range by a solar flare is examined. The proposed explanation is based on the interaction of a flare generated shock front with a magnetic flux tube extending out into the corona over the flare. As the shock wave propagates through the flux tube, Alfven waves are developing and travelling up the tube toward each other, thereby accelerating electrons and protons by the Fermi mechanism and thus filling the top of the flux tube with energetic electrons. Radial oscillations develop as the shock front becomes parallel to the magnetic field direction and the intensity of the synchrotron radiation is modulated by these oscillations. An OSO-5 experiment detected a hard X-ray burst associated with the flare that produced modulated radio emission and X-ray modulations that are attributed to density fluctuations in the X-ray bursts.

Frost, K. J.↗