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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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NASA NTRS1973

Photochemistry of interstellar molecules

The role of photochemistry in determining the lifetime of interstellar molecules is considered. The probability of photodecomposition depends on three factors, including the absorption cross section, the quantum yield or probability of dissociation following photon absorption, and the interstellar radiation field. A more detailed discussion of the photochemistry of five molecules is presented, giving attention to carbonyl sulfide, methyl acetylene, nitric oxide, acetylene, and benzene. Lifetimes of interstellar molecules in unobscured regions are in the range from 5 to 100 years. It is concluded that polyatomic molecules can exist only in dense clouds which protect them from the full interstellar radiation field.

Stief, L. J.↗
NASA NTRS1974

Remote atmospheric sensing with an airborne laser absorption spectrometer

A laser absorption spectrometer, using an infrared laser transmitter and a heterodyne radiometer, can be used from an aircraft or spacecraft to measure altitude profiles of air pollutants and other atmospheric constituents. The technique involves measurement of differential absorption at several wavelengths, using the diffusely reflecting earth's surface to provide a return signal. The pressure broadening of absorption lines allows one to discriminate between high and low altitude absorbers. Application of the technique to measurements of ozone, nitric oxide, and water vapor are presented. CO2 and CO lasers are considered as transmitters. The discussion includes altitude resolution limitations, atmospheric temperature dependence, and frequency stability requirements of the instrument.

Menzies, R. T.↗
NASA NTRS1970

Air pollution from future giant jetports

Because aircraft arrive and depart in a generally upwind direction, the pollutants are deposited in a narrow corridor extending downwind of the airport. Vertical mixing in the turbulent atmosphere will not dilute such a trail, since the pollutants are distributed vertically during the landing and take-off operations. As a consequence, airport pollution may persist twenty to forty miles downwind without much attenuation. Based on this simple meteorological model, calculations of the ambient levels of nitric oxide and particulates to be expected downwind of a giant jetport show them to be about equal to those in present urban environments. These calculations are based on measured emission rates from jet engines and estimates of aircraft performance and traffic for future jetports.

Fay, J. A.↗
NASA NTRS1975

A study of electron density profiles in relation to ionization sources and ground-based radio wave absorption measurements, part 2

The D-region ion production functions are used to calculate the relationship between radio wave absorption and the flux level of X-rays in the 1-8A wavelength band. In order to bring this calculation into agreement with the empirically established relationship, it was found necessary to reduce by, a factor of about 5, the Meira nitric oxide densities below 90 km.

Gnanalingam, S.↗
NASA NTRS1975

Air pollution from aircraft

A model which predicts nitric oxide and carbon monoxide emissions from a swirl can modular combustor is discussed. A detailed analysis of the turbulent fuel-air mixing process in the swirl can module wake region is reviewed. Hot wire anemometry was employed, and gas sampling analysis of fuel combustion emissions were performed.

Heywood, J. B.↗
NASA NTRS1974

Remote atmospheric sensing with an airborne laser absorption spectrometer

A laser absorption spectrometer, using an IR laser transmitter and a heterodyne radiometer, can be used from an aircraft or spacecraft to measure altitude profiles of air pollutants and other atmospheric constituents. The technique involves measurement of differential absorption at several wavelengths, using the diffusely reflecting earth's surface to provide a return signal. The pressure broadening of absorption lines allows one to discriminate between high and low altitude absorbers. Application of the technique to measurements of ozone, nitric oxide, and water vapor are presented. CO2 and CO lasers are considered as transmitters. The discussion includes altitude resolution limitations, atmospheric temperature dependence, and frequency stability requirements of the instrument.

Menzies, R. T.↗
NASA NTRS1974

Effect of pollutant gases on ozone production by simulated solar radiation

The present investigation provides some information related to the problem of ozone destruction by nitric oxide emission from high flying vehicles. It is found that CO and H2O can counteract NO destruction of O3 in laboratory simulations. The addition of CO and H2O to aircraft exhausts could be a practical means of reducing the damage of the UV-filtering ozone layer. It is also discovered that NO is not regenerated as it destroys ozone, except at low stratospheric pressures. It is believed that the presence of H2O and CO gives rise to a series of reactions which provide a kinetically competitive pathway for the NO, causing it to go into NO2 production via these substrates rather than via O3.

Wong, E. L.↗
NASA NTRS1974

An assessment of the potential impact of solid-fueled rocket engines in the stratosphere

The effects of shuttle-emitted HCl on stratospheric ozone are reported. A one-dimensional model of the distribution of trace constituents in the stratosphere and mesosphere is described, and chemical reactions and photodissociation rates in the chlorine chemistry are listed. Analysis of mathematical models is presented, and the results show ozone depletion when emissions are considered to be spread uniformly in the horizontal over a hemisphere and an increase in ozone when emissions are considered in a zone 1000 km wide centered at Cape Kennedy. Sensitivity studies to determine the effects of some assumptions in the model and comparisons with nitric oxide reactions are described. The importance of a two-dimensional model for a proper long term study is noted. Lists of reaction rate coefficients and photodissociation rates for the O-H-N system are included.

Whitten, R. C.↗
NASA NTRS1975

The shape of the future long-haul transport airplane

Long-haul transport plane configurations are discussed that are considered technically feasible within a practical level of near-term technology. Supersonic and transonic aircraft are considered, as well as different types of subsonic transports. It is indicated that superior second-generation supersonic transports are quite feasible technically; in particular, it is shown that problems of fuel consumption, efficient overland flight, and questions on noise and nitric oxides have straightforward engineering solutions. Transonic aircraft are practical but would have to have a different geometry than subsonic aircraft to provide the versatility necessary to compete at one end of their capability with supersonic transports and at the other end, for shorter ranges, with subsonic transports. The shape of subsonic transports is not expected to change noticeably, although recent advances of airfoil technology imply that new subsonic transports would have wings with higher aspect ratios and somewhat less sweep. But large specialized freighter aircraft and very long range laminar flow control or nuclear-powered aircraft with radically new shapes are possible.

Clay, C. W.↗
NASA NTRS1975

The chemistry of atmospheric bromine

Bromine may act as a catalyst for recombination of ozone and could be more efficient than either nitric oxide or chlorine. The lower atmosphere contains small concentrations of gaseous bromine produced in part by marine activity and volatilization of particulate material released during the combustion of leaded gasoline, with an additional contribution due to the use of methyl bromide as an agricultural fumigant. Observations by Lazrus et al., (1975) indicate small concentrations of bromine, about 10 to the -11th power (v/v), in the contemporary stratosphere and appear to imply a reduction of approximately 0.3% in the global budget of O3. Estimates are given for future reductions in O3 which might occur if the use of CH3Br as an agricultural fumigant were to continue to grow at present rates.

Wofsy, S. C.↗
NASA NTRS1975

International Symposium on Combustion, 15th, Tokyo, Japan, August 25-31, 1974, Proceedings

Recent theoretical and experimental studies concerned with detonation and pressure wave combustion interaction, fire and explosion research and safety, heterogeneous combustion, flame-flow interactions, kinetics of elementary reactions, pollution control in and by combustion systems, and ignition are presented. Some of the topics covered include critical power density for direct initiation of unconfined gaseous detonations, extinction of laminar diffusion flames for liquid fuels, combustion of bulk titanium in oxygen, flame propagation in small spheres of unconfined and slightly confined flammable mixtures, kinetics of the reaction of nitric oxide with hydrogen, production of chemi-ions and formation of CH and CH2 radicals in methane-oxygen and ethylene-oxygen flames, NOx emission characteristics in two-stage combustion, and spherical ignition of oxyhydrogen behind a reflected shock wave. Individual items are announced in this issue.

Source record↗
NASA NTRS1976

Infrared emission from the atmosphere above 200 km

The infrared radiation over the range from 4 to 1000 microns from atoms and molecules in the earth's atmosphere, between 200 and 400 km, was calculated. Only zenith lines of sight were considered. The excitation of the atoms and molecules is due to collisions with other molecules and to absorption of radiation from the earth and sun. In some cases, the abundances of the molecules had to be estimated. The most important lines are the forbidden lines from atomic oxygen at 63.1 and 147 micron, and the vibration-rotation band of nitric oxide at 5.3 micron. These lines can have intensities as high as a few times 0.001 ergs/sq cm/sec/steradian at 200 km altitude. In addition, the vibration-rotation bands of NO(+) at 4.3 micron and CO at 4.7 micron and the pure rotation lines of NO and NO(+) could be detected by infrared telescopes in space.

Simpson, J. P.↗
NASA NTRS1976

Ion composition in a noctilucent cloud

Ion composition at mesospheric altitudes was measured and compared between high and mid-latitude sites under summer daytime conditions. Rocket-borne measurements were made with pumped quadrupole ion mass spectrometers. The mid-latitude data were obtained at Wallops Island, Virginia on June 30, 1973, at 1510 LMT. Large quantities of hydronium cluster ions were observed through 109+, with maximum concentrations at 55+ and 73+. Also, cluster ions of nitric oxide were observed through 84+. The high latitude launch occurred at Kiruna, Sweden on August 2, 1973, at 0700 LMT following visual sighting of a noctilucent cloud on the prior evening. The data near mesopause shows cluster ions, but also a preponderance of heavy ions between 90 and 145 AMU, with groupings 18 AMU apart but unrelated to the more typical cluster ions. One possible set of consistent identifications leads to iron and iron oxide hydrates. These results may suggest the presence of metallic particulates and ions which form hydrated clusters ions.

Goldberg, R. A.↗
NASA NTRS1976

Polar enhancements of nightglow emissions near 6230A

Night airglow emissions near 6230A, as observed from the Ogo 4 spacecraft in 1967-8, show enhancements at polar latitudes by more than a factor of ten over mid and low latitude values. The enhancements are generally not symmetrical with either the north pole or the auroral oval. They are attributed in part to increases in the Meinel band emissions of OH, particularly as associated with a stratospheric warming event, and in part to increases in nitric oxide densities in the lower thermosphere.

Reed, E. I.↗
NASA NTRS1975

Seasonal variations of NO and O3 at altitudes of 18.3 and 21.3 km

Nitric oxide and ozone concentrations have been measured in situ from a high-altitude research aircraft. Data which show the variations of NO and O3 with the time of year are presented for altitudes of 18.3 and 21.3 km. The extreme values of the observed NO concentrations at 21.3 km are 1.2 billion per cu cm in summer and 0.2 billion per cu cm in winter. At 18.3 km the extreme values are 1.6 billion per cu cm in summer and 0.1 billion per cu cm in winter. The smoothed NO seasonal data show a variation of about a factor of 2.5 at 21.3 km and a factor of 4 at 18.3 km. The ozone data show the generally expected magnitude and seasonal variation. We have used a photochemical model employing the measured ozone concentrations, the mean solar zenith angle, and seasonal HNO3 data reported by others to predict the seasonal NO variation at 20 km. The result is a summer-to-winter NO ratio of 2.5 which is in fair agreement with the observed ratios.

Loewenstein, M.↗
NASA NTRS1976

Simultaneous partial reflection and meteor radar wind observations at Urbana, Illinois, during the winter of 1974-1975

A program of observation was undertaken during the winter of 1974-1975 utilizing the meteor winds radar and partial reflection system at Urbana, Illinois. The north-south component of the prevailing wind representative of 80-100 km altitude was deduced for four 24-h observational periods during which partial reflection measurements of D-region electron density were made. These observations indicate southward mean motion during periods of higher electron density and northward mean motion during periods of lower electron density. This is consistent with the idea that increases in the transport of nitric oxide from the auroral zone is a cause of winter increases in D-region electron density at midlatitudes.

Geller, M. A.↗
NASA NTRS1975

A simulation experiment of photochemical reactions in the mesosphere

An ionospheric simulation experiment has been performed in a large vacuum chamber. The chamber is filled with NO and other gases including N2, O2, CO2, NH3 and H2O in the pressure range of 0.01 torr. A lamp which produces photons at 1236- and 1165-A by means of microwave discharge in krypton is utilized as an ionization source. In addition to 30+ large quantities of the water cluster ions 55+, H3O(+).(H2O)2, 73+, H3O(+).(H2O)3 and 91+, H3O(+).(H2O)4 were observed when nitric oxide and water were present. This closely approximates the condition of the terrestrial D region. After long periods of UV irradiation 74+ and 104+ ions grow in intensity. These ions are tentatively identified as NO(+).N2O and NO(+).NO.N2O. In addition the series 18+, 36+, 54+, and 72+ is detected which can be labeled NH4(+), NH4(+).(H2O), NH4(+).(H2O)2 and NH4(+).(H2O)3. These same species of ions are observed with the introduction of ammonia into the chamber. Presumably both N2O and NH3 are products of the photolysis.

Fugono, N.↗
NASA NTRS1976

Remote measurements of ambient air pollutants with a bistatic laser system

The ambient air pollutants ozone, nitric oxide, and ethylene have been monitored in the Pasadena area with a bistatic IR laser apparatus. These pollutants were measured with a differential absorption technique, using selected wavelengths in the 9.5-, 5.2-, and 10.5-micron regions, respectively. The transmitted laser radiation was detected using both direct and heterodyne detection techniques. In the direct detection case, cube corner retroreflectors provided the return, and the heterodyne detection responded to scattered radiation from various rough surfaces, ranging from 400 m to 1.9 km in distance from the apparatus. Significant departures from ambient background concentration levels were noticed in the region near a local freeway during periods of moderate and heavy traffic.

Menzies, R. T.↗