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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 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Miniature carbon dioxide sensor

Sensor with no moving parts measures carbon dioxide partial pressures of 0 to 40 mm Hg for total pressures up to 14 psia with a full scale accuracy of 5 percent.

Mc Henry, T. F.↗
NASA NTRS1972

A reliable liquid helium detector

Detector and indicator system, utilizing commercial perforated germanium cryogenic thermometer as level sensor containing adjustable level discriminator with indicators, operates reliably over pressure range from 50 to 900 mm Hg without electronic adjustments.

Krawczonek, W. M.↗
NASA NTRS1971

Ion thruster diagnostics using spectral line amplitudes

The optical radiation from the plasma discharge of an electron bombardment mercury ion thrustor was investigated. Using the measured ratio of the Hg I line amplitude at 3655 A to that at 3650 A, a theory incorporating a bimodal electron distribution (Maxwell electrons plus primary electrons) was used to obtain the average electron temperature and primary electron fraction in the thruster ion chamber. The electron temperature ranged from about 1.2 eV to 6.6 eV; whereas the primary electron fraction varied from zero percent to about 5 percent. These values depended upon the discharge voltage and the radial location of the measurement. The percentage of doubly ionized mercury produced in the chamber was also determined as a function of discharge voltage.

Milder, N. L.↗
NASA NTRS1971

The photolysis of CO2 at 1849 and 2139A

The quantum yield for CO2 photodissociation at 25 C was found to be 1.08 + or - 0.12 for direct photolysis at 1849 A and between 200 and 800 torr; 0.48 + or - 0.02 for the Hg 6(1 P 1) sensitized decomposition between 130 and 730 torr; and 0.16 + or - 0.05 for the direct photolysis at 2139 A and between 300 and 600 torr. At these wavelengths, there was insufficient energy found to produce O(1 D). The primary process used is CO2 + hv yields CO + O(3 P).

Krezenski, D.↗
NASA NTRS1971

Metabolic effects of artificial environments

The mechanisms by which inert gases influence metabolism were investigated from several viewpoints. Groups of rats were exposed at the thermal neutral temperature of the respective mixtures, to normoxic (P sub A 02 = 100 mm Hq) environments with argon, helium or nitrogen as the diluent at a total pressure of one atmosphere. The possible influence of diluent gases on oxygen transport to the cell was examined with hypoxic (P sub A O2 = 70 mm Hg) mixtures of the same diluent gases. Metabolic measurements included food, water, and oxygen consumption, CO2 production, hematocrit and the rate C-14O2 of expiration subsequent to intraperitoneal injection of acetate-1-C-14 or glucose UL-C-14. Argon-exposed animals showed a consistently decreased metabolic rate while, on the other hand, helium-exposed rats did not significantly alter metabolic rate relative to nitrogen. Certain indices, including acetate and glucose utilization, suggested that helium attenuated the imposed hypoxia at the cellular level while argon facilitated it as compared with nitrogen. These results suggest that metabolic influence of helium is largely thermal in nature while argon has a significant direct metabolic effect and that diluent gases may selectively influence oxygen availability to the interior of the cell.

Jordan, J. P.↗
NASA NTRS1972

Mobilities of uranium and mercury ions in helium

The mobilities of mass-identified U(+) and Hg (+) ions in helium were determined in a drift tube-mass spectrometer. For uranium ions, a reduced mobility value is obtained at 305 K and a standard gas density of 2.69 x 10 to the 19th power/cu cm. The mobility of mercury ions is in agreement with two previous determinations. The effect of fast ion injection in drift mobility measurements is discussed, and a technique to circumvent these problems is described. The results are compared with existing theories of ion mobilities.

Johnsen, R.↗
NASA NTRS1971

A pressure scanning Fabry-Perot magnetometer.

Description of an oscillating magnetic analyzer (KDP crystal plus Glan-Thompson prism) coupled to an echelle-interferometer spectrograph, and of single-slit magnetometer which by pressure variations can be made to scan the entire profiles of the circularly and linearly polarized Zeeman components. Freon gas is used as the scanner gas with wavelength displacements of 0.02 A per 0.1 in. Hg pressure change at the NaD lines. The available scan range is 15 A in the visual spectral region.

Fay, T. D.↗
NASA NTRS1971

Splanchnic vasoconstriction in hyperthermic man - Role of falling blood pressure.

Results of a study in which six supine resting subjects, wearing water-perfused suits, had body skin temperature controlled at 35 C for 30 min (control period), then rapidly increased to 40.5 C for 43 to 50 min (heating period) in a two-part experiment. In the first part of the experiment arterial mean pressure (MP) in three men was increased back to, or above control levels at the 30 to 35th min of heating by total occlusion of both legs for 8 to 10 min. Splanchnic blood flow (SBF), which had fallen from 1.4 to 0.9 L/min at occlusion, rose only 0.05 L/min during occlusion. Splanchnic vascular resistance (SVR) rose throughout heating and occlusion. In the second part of the experiment (three men) SBF fell despite a spontaneous rise in MP and aortic pulse pressure prior to leg occlusion. Cardiac output (CO) was measured just before, during and after occlusion. Occlusion raised MP 10 to 15 mm Hg and reduced CO only slightly. It is concluded that falling MP or aortic pulse pressure are not major causes of the splanchnic vasoconstriction in response to heating man.

Rowell, L. B.↗