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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 901 records · Page 50

A mass spectrometer concept for identifying planetary atmosphere composition

The design and use of mass spectrometers to measure and identify atmospheric gas compositions of planets are discussed. Special emphasis during the design phase was given to dynamic range that the instrument must have, mass range the instrument must cover, and precision of the measurements that are necessary, for example to confirm isotope ratios. Some problems encountered in the use of the instrument are illustrated using data from the Pioneer-Venus program.

Spencer, N. W.↗

The log N-log S curve for 3CR radio galaxies and the problem of identifying faint radio galaxies

The log N-log S slope of optically identified galaxies in the 3CR catalog is analyzed for galaxies with flux levels greater than 10 Jy and located at galactic latitudes greater than 7 deg. For the 86 galaxies with known redshifts, the slope is found to be about 1.16; for all 119 galaxies, the slope is found to be about 1.50. If the 113 unidentified sources are included, the slope steepens to about 1.81. It is shown that this steepness is caused by the unidentified sources. Assuming that the slope is due to evolution at redshifts of 1 to 3 and that the unidentified sources are bright ellipticals, the mean redshifts and apparent brightnesses of these galaxies are calculated. The results indicate that it is impossible to observe the unidentified sources with existing ground-based telescopes, implying that it is presently impossible to establish directly that evolution is responsible for the steep log N-log S curve of the 3CR galaxies.

Burbidge, G. R.↗

The role of technetium-99m stannous pyrophosphate in myocardial imaging to recognize, localize and identify extension of acute myocardial infarction in patients

The ability of technetium-99m stannous pyrophosphate myocardial scintigrams to aid diagnostically in recognizing, localizing, and identifying extension of acute myocardial infarction in patients was evaluated. The present study is an extension of previous animal and patient evaluations that were recently performed utilizing this myocardial imaging agent.

Willerson, J. T.↗

On identifying frequencies and damping in subcritical flutter testing

Various procedures that might be used in evaluating system response characteristics as involved in subcritical flight and wind-tunnel flutter testing of aircraft are reviewed with emphasis on the means for eliminating or minimizing the contamination effects produced by an unknown noise in the input. Results of a procedure developed for identifying modal frequency and damping values, and a possible way for making a detailed evaluation of system parameters, are also given.

Houbolt, J. C.↗