Visualization of surficial and internal structure and chemistry utilizing CT and neutron imaging
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computer tomography life detection astrobiology↗
Engineering topics
Thompson, A. R.
Publications and source records attributed to Thompson, A. R..
A VLA experiment: Planning for Voyager at Neptune
A very large array (VLA) engineering experiment was conducted on the night of July 22, 1983 to explore one aspect of the potential for the VLA to support Voyager at its Neptune encounter in August of 1989. Specifically, the experiment tested the abiliy of the VLA to self-calibrate on a natural radio source whose effective signal strength is the same as Voyager's will be at its Neptune encounter. The experiment was successful and supported the belief that the VLA would be able to be self-calibrated with Voyager's signal.
Layland, J. W.↗
Evaluation of the feasibility of scale modeling to quantify wind and terrain effects on low-angle sound propagation
The feasibility of acoustical scale modeling techniques for modeling wind effects on long range, low frequency outdoor sound propagation was evaluated. Upwind and downwind propagation was studied in 1/100 scale for flat ground and simple hills with both rigid and finite ground impedance over a full scale frequency range from 20 to 500 Hz. Results are presented as 1/3-octave frequency spectra of differences in propagation loss between the case studied and a free-field condition. Selected sets of these results were compared with validated analytical models for propagation loss, when such models were available. When they were not, results were compared with predictions from approximate models developed. Comparisons were encouraging in many cases considering the approximations involved in both the physical modeling and analysis methods. Of particular importance was the favorable comparison between theory and experiment for propagation over soft ground.
Anderson, G. S.↗
Shock Mounting for Heavy Machines
Elastomeric bearings eliminate extraneous forces. Rocket thrust transmitted from motor to load cells via support that absorbs extraneous forces so they do not affect accuracy of thrust measurements. Adapter spoked cone fits over forward end of rocket motor. Shock mounting developed for rocket engines under test used as support for heavy machines, bridges, or towers.
Thompson, A. R.↗
The effects of a satellite power system on ground-based astronomy
The effects of power transmission from the solar power satellite and of radiation from the ground based rectennas on radio astronomy, radar astronomy, and optical astronomy are discussed. Interference sources, acceptable signal and noise levels, and conflicting site requirements for observatories and rectennas are considered.
Thompson, A. R.↗
VLA observations of stellar planetary nebulae
Coordinates, dimensions, 4885-MHz flux densities, and brightness temperatures of K3-2, NGC 6833, Ps 1, II 5117, Me 2-2, Hb 12, Vy 1-1, and M1-5 are reported. In two other cases, H3-29 and H3-75, confused extended structure was detected in which the nebula could not be identified with certainty. He 2-467, M1-2, and Peterson's H-alpha object in M15 were also included in the observations but not detected with an upper limit of less than 10 mJy. The observations are compared with some of the previous optical and radio data, such as log S(H-beta). Distances are computed from the present data with standard assumptions. Corresponding linear radii range below 0.1 pc, among the smallest in previous distributions of radius.
Johnson, H. M.↗
The distribution of linear polarization in Cassiopeia A at wavelengths of 9.8 and 11.1 cm.
Two interferometer investigations of the polarization of Cassiopeia A employed beams of small dimensions as compared with the source. One was made at a wavelength of 9.8 cm and the other, which was more detailed, was made at a wavelength of 11.1 cm. Previous studies of the polarization of Cassiopeia A have covered either shorter wavelengths, where depolarization is small, or longer wavelengths where little polarized radiation remains. Comparison of the results of these studies with the new data near the 10-cm wavelength yields information on the rate of change of the radiation depolarization and the rotation of the plane of the electric vector as functions of wavelength. It is shown that the results can be explained in terms of a model of the source incorporating Faraday depolarization.
Downs, G. S.↗