Engineering topics

Dubisch, R.

Publications and source records attributed to Dubisch, R..

3 records

NASA NTRS1974

On the averaging of ratios of specific heats in a multicomponent planetary atmosphere

The use of adiabatic relations in the calculation of planetary atmospheres requires knowledge of the ratio of specific heats of a mixture of gases under various pressure and temperature conditions. It is shown that errors introduced by simple averaging of the ratio of specific heats in a multicomponent atmosphere can be roughly 0.4%. Therefore, the gamma-averaging error can become important when integrating through the atmosphere to a large depth.

Dubisch, R.↗

NASA NTRS1973

Variable features on Mars 2: Mariner 9 global results

Mariner 9 observations of time variable Martian dark areas and semi-tone areas are commonly resolved into streaks and splotches caused by sand storm particles. Bright streaks are formed by the smaller particles and require exceptionally high velocities for their formation as compared with the more easily saltated larger particles in dark streak areas.

Sagan, C.↗

NASA NTRS1972

Variable features on Mars - Preliminary Mariner 9 television results.

Systematic Mariner 9 photography of a range of Martian surface features, observed with all three photometric angles approximately invariant, reveals three general categories of albedo variations: (1) an essentially uniform contrast enhancement due to the dissipation of the dust storm; (2) the appearance of splotches, irregular dark markings at least partially related to topography; and (3) the development of both bright and dark linear streaks, generally emanating from craters. Some splotches and streaks vary on characteristic timescales of about two weeks; they have characteristic dimensions of kilometers to tens of kilometers. The morphology and variability of streaks and splotches, and the resolution of at least one splotch into an extensive dune system, implicate windblown dust as the principal agent of Martian albedo differences and variability.

Sagan, C.↗