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At least 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Concentrations of CH4, CO, CO2, H2, H2O and N2O in the upper stratosphere

On 23 May 1973 a cryogenic air sampler was flown on an Aerobee rocket from White Sands Missile Range. A large air sample was collected between 40 and 50 km altitude and successfully recovered for water vapor and trace gas analysis. The results were as follows: water vapor, 4.0 (+1.3 or - 0.9) ppmV; methane, 0.37 + or - 0.01 ppmV; molecular hydrogen, 0.47 + or - 0.02 ppmV; carbon monoxide, 0.05 + or - 0.01 ppmV; carbon dioxide, 316.2 + or - 2.8 ppmV; and nitrous oxide, 3 + or - 7 ppb.

Ehhalt, D. H.↗
NASA NTRS1976

Radio detection of H2O in comet Bradfield (1974b)

Results of observations of comet Bradfield using the Haystack telescope are summarized with emphasis on the detection of the 1.35 cm emission line of water in the comet. The excitation of water and methyl cyanide in comets is briefly considered.

Jackson, W. M.↗
NASA NTRS1977

Stimulated Raman scattering and the extreme high-velocity H2O maser features in W49

Stimulated Raman scattering of the intense 22.2-GHz water-vapor maser radiation within W49 is examined as a possible explanation of the extremely broad spectrum of W49 extending to + or - 200 km/sec apparent Doppler velocity. Under the most favorable conditions, Raman scattering from ammonia molecules is calculated to be observable. It is unlikely that the Raman process contributes appreciably in the case of W49, as it fails to predict the observed spatial and spectral distribution of the radiation.

Boyd, R. W.↗
NASA NTRS1977

Physical-chemical examination of the N2O3-SO3-H2O system

It was found that when (NO)HSO4 is added to absolute H2SO4, specific conductivity rises sharply, possibly due to an increase in mutual interionic effects and viscosity as the (NO)HSO4 concentration rises. The addition of SO3 to the solution yielded a precipitate; a combination of analysis, IR spectroscopy and X-ray diffraction techniques indicated that this precipitate was (NO)HS2O7.

Linstroem, C.↗
NASA NTRS1978

Advanced solid electrolyte cell for CO2 and H2O electrolysis

A solid electrolyte cell with improved sealing characteristics was examined. A tube cell was designed, developed, fabricated, and tested. Design concepts incorporated in the tube cell to improve its sealing capability included minimizing the number of seals per cell and moving seals to lower temperature regions. The advanced tube cell design consists of one high temperature ceramic cement seal, one high temperature gasket seal, and three low temperature silicone elastomer seals. The two high temperature seals in the tube cell design represent a significant improvement over the ten high temperature precious metal seals required by the electrolyzer drum design. For the tube cell design the solid electrolyte was 8 mole percent yttria stabilized zirconium oxide slip cast into the shape of a tube with electrodes applied on the inside and outside surfaces.

Shumar, J. W.↗
NASA NTRS1978

Upper bound and probable value of the rate constant of the reaction OH + HO2 yields H2O + O2

Discharge-flow experiments at 295 K of the OH + HO2 reaction are described in which excess O3 is added to OH through a movable injector; OH concentration is measured downstream by resonance fluorescence with and without addition of excess NO just upstream of the detector so that both OH concentration and OH concentration + HO2 concentration are determined independently. The data are compared with a computer model involving 12 reaction steps. A simple sensitivity analysis is carried out to establish how errors in the other 'known' rate constants affect the data fit. Best agreement is obtained between computer calculations and experiments when k1 for the OH + HO2 reaction is in the range 2-3 x 10 to the -11th cu cm/s. Values above about 5 x 10 to the -11th are very unlikely whereas those below about 1 x 10 to the -11th are less strongly excluded.

Chang, J. S.↗
NASA NTRS1979

H2O masers near OB associations

Four new water masers have been found in the vicinity of three OB associations. One of these, in Cep OB3, is among the most intense sources yet discovered and may be related to the most recent epoch of star formation in the OB association. Two others, one in CMa OB1, the other in M16, have large radial velocities relative to their associated molecular clouds. These results are discussed in the context of star formation and CO line self-reversal within the individual sources.

Blitz, L.↗
NASA NTRS1979

Intensities and N2 collision-broadening coefficients measured for selected H2O absorption lines between 715 and 732 nm

Intensities and N2 collision-broadening coefficients are measured for 62 water vapor absorption lines between 715 and 732 nm potentially applicable to laser remote sensing of atmospheric water vapor. Absolute line strengths and widths were determined from spectra corrected for instrument resolution, air-path absorption and Lorentz and Doppler broadening for pure water vapor and water vapor-nitrogen mixtures in a multipass absorption cell with a base path length of 25 m (White cell). Line strengths are observed to range from 4 x 10 to the -25th to 4 x 10 to the -23rd kayser/molecule per sq cm, and collision broadening coefficients are found to be approximately equal to 0.1 kayser/atm.

Wilkerson, T. D.↗
NASA NTRS1980

Hydrogen production by photoelectrolytic decomposition of H2O using solar energy

Photoelectrochemical systems for the efficient decomposition of water are discussed. Semiconducting d band oxides which would yield the combination of stability, low electron affinity, and moderate band gap essential for an efficient photoanode are sought. The materials PdO and Fe-xRhxO3 appear most likely. Oxygen evolution yields may also be improved by mediation of high energy oxidizing agents, such as CO3(-). Examination of several p type semiconductors as photocathodes revealed remarkable stability for p-GaAs, and also indicated p-CdTe as a stable H2 photoelectrode. Several potentially economical schemes for photoelectrochemical decomposition of water were examined, including photoelectrochemical diodes and two stage, four photon processes.

Rauh, R. D.↗
NASA NTRS1980

The properties of clusters in the gas phase. IV - Complexes of H2O and HNOx clustering on NOx/-/

Thermodynamic quantities for the gas-phase clustering equilibria of NO2(-) and NO3(-) were determined with high-pressure mass spectrometry. A comparison of values of the free energy of hydration derived from the data shows good agreement with formerly reported values at 296 K. New data for larger NO2(-) and NO3(-) hydrates as well as NO2(-)(HNO2)n were obtained in this study. To aid in understanding the bonding and stability of the hydrates of nitrite and nitrate ions, CNDO/2 calculations were performed, and the results are discussed. A correlation between the aqueous-phase total hydration enthalpy of a single ion and its gas-phase hydration enthalpy was obtained. Atmospheric implications of the data are also briefly discussed.

Lee, N.↗
NASA NTRS1980

Absolute rate constant of the reaction OH + H2O2 yields HO2 + H2O from 245 to 423 K

The absolute rate constant of the reaction between the hydroxyl radical and hydrogen peroxide was measured by using the discharge-flow resonance fluorescence technique at total pressure between 1 and 4 torr. At 298 K the result is (1.64 + or - 0.32) x 10 to the -12th cu cm/molecule s. The observed rate constant is independent of pressure, surface-to-volume ratio, the addition of vibrational quenchers, and the source of OH. The temperature dependence has also been determined between 245 and 423 K; the resulting Arrhenius expression is k cu cm/molecule s is equal to (2.51 + or - 0.6) x 10 to the -12th exp(-126 + or - 76/T).

Keyser, L. F.↗