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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Shapes and widths of ammonia lines collision-broadened by hydrogen.

Measurement of half-widths and shapes of several rotational lines in nu sub 2 bands of ammonia, collision-broadened by hydrogen. The measurements were made at room temperature with a spectral resolution of 0.15 per cm. Line intensities and self-broadened half-widths were also measured. From the line-intensity data, an estimate of S sub band = 600 plus or minus 30 per sq cm per atm has been derived for the absolute intensity of the pair of bands. Hydrogen-broadened half-widths of all the lines have been found to be equal to 0.075 plus or minus 0.004 per cm per atm. For all the lines measured, shapes of the lines in NH3-H2 collisions seem to conform to the super-Lorenz line shape proposed by Varanasi et al. (1972) for dipole quadrupole collisions.

Varanasi, P.↗
NASA NTRS1973

Rapid gas-phase reactions - The reaction of ammonia and the methylamines with boron trifluoride. III - Pressure dependence of rate constant.

A steady-state flow apparatus, shown earlier to be suitable for the study of rapid gas reactions, has been used to determine the pressure dependence of the relative quasi-bimolecular rate constants for the reactant pairs ammonia (AM)-trimethylamine (TMA) and dimethylamine (DMA)-trimethylamine in reaction with boron trifluoride. The pressure dependence of the former was determined in the range 0.03-75 torr and that of the latter in the range 0.02-720 torr.

Glicker, S.↗
NASA NTRS1973

Product distributions and rate constants for ion-molecule reactions in water, hydrogen sulfide, ammonia, and methane

The thermal energy, bimolecular ion-molecule reactions occurring in gaseous water, hydrogen sulfide, ammonia, and methane have been identified and their rate constants determined using ion cyclotron resonance methods. Absolute rate constants were determined for the disappearance of the primary ions by using the trapped ion method, and product distributions were determined for these reactions by using the cyclotron ejection method. Previous measurements are reviewed and compared with the results using the present methods. The relative rate constants for hydrogen-atom abstraction, proton transfer, and charge transfer are also determined for reactions of the parent ions.

Huntress, W. T., Jr.↗
NASA NTRS1974

The abundance of ammonia on Jupiter, Saturn and Titan

From recent spectra of Jupiter, Saturn and Titan in the 6450-A band of NH3, new values of the abundance of ammonia are derived for Jupiter and Saturn. NH3 abundances of 13 plus or minus 3 m-Am on Jupiter and 2 plus or minus 1 m-Am on Saturn were found. High resolution profiles of NH3 lines on Jupiter are used to estimate a pressure of 2.1 atm at the line formation level in the Jovian atmosphere. In the case of Titan, an NH3 abundance of less than 2 m-Am was found. The implications of these results are discussed.

Encrenaz, T.↗
NASA NTRS1975

Optical constants of solid ammonia in the infrared

No direct measurements of the refractive index for solid ammonia could be obtained because of failures in attempts to map the reflection spectrum. Kramers-Kronig techniques were, therefore, used in the investigation. The subtractive Kramers-Kronig techniques employed are similar to those discussed by Ahrenkiel (1971). The subtractive method provides a more-rapid convergence than the conventional techniques when data are available over a limited spectral range.

Robertson, C. W.↗
NASA NTRS1975

Ultraviolet optical constants of water and ammonia ices

A method reported by Tempelmeyer and Mills (1968) for the determination of real refractive indices of transparent films was used in the investigation. It was found that the fringe period for a transparent film can be used to approximate the period for a semitransparent film near its extremum. The experimental apparatus is discussed along with details regarding the employed technique. Graphs are presented concerning the refractive index and the absorption coefficients for amorphous water ice and amorphous ammonia ice.

Browell, E. V.↗
NASA NTRS1976

Shuttle ECLSS ammonia delivery capability

The possible effects of excessive requirements on ammonia flow rates required for entry cooling, due to extreme temperatures, on mission plans for the space shuttles, were investigated. An analysis of worst case conditions was performed, and indicates that adequate flow rates are available. No mission impact is therefore anticipated.

Source record↗