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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Interdisciplinary study of atmospheric processes and constituents of the mid-Atlantic coastal region.

Past research projects for the year 1974-1975 are listed along with future research programs in the area of air pollution control, remote sensor analysis of smoke plumes, the biosphere component, and field experiments. A detailed budget analysis is presented. Attachments are included on the following topics: mapping forest vegetation with ERTS-1 MSS data and automatic data processing techniques, and use of LARS system for the quantitative determination of smoke plume lateral diffusion coefficients from ERTS images of Virginia.

Kindle, E. C.↗
NASA NTRS1974

Interaction between polymer constituents and the structure of biopolymers

The paper reviews the current status of methods for calculating intermolecular interactions between biopolymer units. The nature of forces contributing to the various domains of intermolecular separations is investigated, and various approximations applicable in the respective regions are examined. The predictive value of current theory is tested by establishing a connection with macroscopic properties and comparing the theoretical predicted values with those derived from experimental data. This has led to the introduction of a statistical model describing DNA.

Rein, R.↗
NASA NTRS1975

Data set for background investigation of atmospheric constituents for Cape Henry site: August 5-22, 1974

The laboratory was located within the Fort Story Military Reservation at Cape Henry between 5 August and 21 August 1974. Total sulfur, total hydrocarbons, NO, NO2, Nox, and O3 were monitored and reported as hourly averages. Visibility was measured using an integrating nephelometer and reported as hourly averages. Twenty-four hour averaged mass loading was determined using two high volume air samplers located on different levels (25' and 50') at the site. Temperature, wind speed, relative humidity, barometric pressure and solar radiation intensity were measured at the site or supplemented by readings taken by the U. S. Coast Guard at the Cape Henry Light House.

Source record↗
NASA NTRS1976

Seasonal variation of neutral thermospheric constituents in the Northern Hemisphere

The Atmosphere Explorer-C satellite carries a large number of experiments including an open source neutral mass spectrometer. Among the measurements obtained with this instrument were ones of particle densities of N2, O, and He at northern latitudes in early February and late June 1974. The orbital geometry of the satellite was such that comparisons could be made between the winter and summer values at the same altitudes and latitudes and at similar local solar times. The helium density shows in midmorning a winter to summer enhancement of a factor of 29 at 400 km. The enhancement at other altitudes, both higher and lower, is less. At 250 km the winter/summer oxygen ratio is 1.7, whereas the winter/summer nitrogen ratio is 0.6. Both ratios decrease with increasing altitudes. The analysis identifies an oxygen enhancement at low altitudes in winter and at high altitudes in summer.

Mauersberger, K.↗
NASA NTRS1976

Organic constituents in eolian dust and surface sediments from northwest Africa

Samples of eolian dust and comparably sized desert surface sediment samples collected over widely scattered regions of northwest Africa were analyzed for carbon, nitrogen, and hydrogen content and total carbohydrate. Infrared analysis and gas chromatographic analysis were also performed on organic components extracted from several of these samples. Although the total carbon content of the eolian dust samples varies from 2.8 to 7.0% by weight, the organic carbon component is relatively uniform at 2.9 + or - 0.5%. By comparison, the average organic carbon content of the African surface sediments is 0.7 + or - 0.5%. Total carbohydrate content averages 0.128% for the dust and 0.022% for the desert sediments. It is shown that these desert regions are not presently the principal sources of eolian material transported over the North Atlantic Ocean.

Lepple, F. K.↗
NASA NTRS1977

Study of dynamics of minor constituents in the thermosphere

The global distribution of helium and argon in the terrestrial thermosphere is described. It is based on the extension of a three-dimensional single-fluid numerical model of the thermosphere previously developed by the authors to treat the dynamics of a minor gas imbedded in a background gas made up of N2, O2, and O. Empirical models of the upper atmosphere, based on satellite drag and mass spectrometer data, are used to specify the background gas density and temperature as functions of altitude, latitude, and local time for a given day of the year. Effects of solar activity, eddy diffusion, and exospheric transport on the global distribution of minor gases are investigated.

Straus, J. M.↗
NASA NTRS1977

Interhemispheric survey of minor upper atmospheric constituents during October - November 1976

The CV-990 aircraft coordinated several flights with a NASA U-2 aircraft, NOAA ground station measurements in Alaska, Hawaii, and American Samoa, and with Australian and New Zealand ground stations, aircraft, and a balloon experiment in the Southern hemisphere. Data were obtained for species including ozone, total ozone, the oxides of nitrogen, the chlorofluoromethanes, water vapor, nitric acid, carbon monoxide, carbon dioxide, hydrogen chloride, Aitken nuclei, ammonia, aerosols, temperatures, and winds. Individual experiment results and selected analyses are presented. The experimental data include total column densities, latitude variations, interhemisphere differences, and vertical profiles.

Gauntner, D. J.↗
NASA NTRS1976

Fluorine as a constituent in lunar magmatic gases

Fluorine surface deposits on Apollo 15 green glass, Apollo 17 orange glass, and on vesicle linings from Apollo 15 basalts were studied by a resonant nuclear reaction technique. Surface layers of about 10 to the 15th F atoms/sq cm were observed on unbroken spheroidal glass surfaces, whereas thinner (about 10 to the 14th atoms/sq cm) deposits were found on the vesicle linings.

Goldberg, R. H.↗
NASA NTRS1977

Effects of experimental hypogravity on peroxidase and cell wall constituents in the dwarf marigold

Dwarf marigolds grown from seed under experimental hypogravity are modified in lignin content, hemicellulose composition and peroxidase activity. The two conditions used, clinostats and flotation, induced changes differing in magnitude but qualitatively similar. Most responses on clinostats required correction for vertical axis rotational effects, thus limiting the value of these instruments in free-fall simulation. These findings extend earlier observations suggesting that increased peroxidase and decreased lignin are characteristic of growth under experimental hypogravity.

Siegel, S.↗
NASA NTRS1978

Theoretical simulation of solar spectra in the middle ultraviolet and visible for atmospheric trace constituent measurements

Two balloon flights reaching float altitudes of approximately 30 and 40 km respectively, were used to obtain scans of the ultraviolet and visible solar spectra. Both flights covered the UV (2800-3500A) at approximately 0.3A resolution and the visible at approximately 0.6A. Numerous scans were obtained during ascent and from float for both flights. All spectral scans obtained at float, from high sun to low sun, were calibrated in wavelength by using several standard solar spectra for line position references. Comparisons of low sun scans and high sun scans show significant atmospheric continuum extinction and have the potential of being used to identify atmospheric lines superimposed on the attenuated solar spectrum. The resolution was mathematically degraded to approximately 5A to better see the broad band atmospheric extinction. This low resolution is also appropriate for the available low resolution absorption coefficients of NO2 and O3, allowing the identification of NO2 and O3 features on the sunset spectra.

Goldman, A.↗
NASA NTRS1978

Study of dynamics of minor constituents in the thermosphere, addendum

Numerical studies of a model of the earth's thermosphere are presented. The distribution of thermospheric helium was investigated. Changes in the global transport of helium under solstice conditions caused by a small increase in the latitudes at which the background gas pressure extremes occur lead to much better agreement of the model predictions with data taken by the mass spectrometers on board the ESRO-4 and OGO-6 satellites. The model was applied to a study of the global distributions of atmospheric gases (N2, O2, and O) at both equinox and solstice with emphasis on the winter enhancement of atomic oxygen in the lower thermosphere. Comparison of the results with measurements taken by the ESRO-4 mass spectrometer indicates that the distribution of atomic oxygen is generally a result of global transport by winds.

Straus, J. M.↗
NASA NTRS1978

Travelling neutral disturbances and minor constituent particle mass

The mass cut-offs for critical or resonant coupling of minor species acoustic waves (so-called travelling neutral disturbances) and acoustic-gravity waves in the main atmosphere are shown and explained. The effects of vertical temperature gradients and the diffusion of the minor species on the mass cut-offs are also demonstrated. The wave characteristics of these minor species waves are examined. The wave number surface is shown to be such that energy and group velocity directions are more nearly vertical than those of gravity waves for the same phase velocity direction. It is expected that these coupled waves, when properly excited, will act to damp gravity waves and redistribute energy vertically. Implications for the thermosphere and mesosphere are discussed. Under ordinary conditions such resonant coupling is judged more likely for lighter mass species, such as helium and hydrogen.

Gross, S. H.↗
NASA NTRS1978

Measurements of constituents of interest in the photochemistry of the ozone layer using infrared techniques

Infrared solar spectra and infrared atmospheric emission spectra were obtained from the ground, from aircraft and from balloons. The initial detection of most stratospheric molecules was achieved by the solar spectral technique because better resolution helps remove interference from other molecules. Because the sun is an intense source of radiation, the resolution which can be obtained with good signal-to-noise, is greater than with atmospheric emission spectroscopy. Data are generally taken using a method that enhances the number of molecules in the optical path i.e. at large solar zenith angles for solar spectra and at low elevation angles for atmospheric emission spectra. The search for molecules which are predicted to be present but which, the detection of a molecule known to be present from other measurement techniques but observed for the first time in infrared solar spectra, and some further data on the variability of HNO3 are discussed.

Murcray, D. G.↗
NASA NTRS1979

Theoretical simulation of solar spectra in the middle ultraviolet and visible for atmospheric trace constituent measurements

The data compiled during the study allowed a detailed examination of the attenuation of the solar radiance by the combined effect of the atmospheric trace gases and the SAGE filters. The case of the 0.44 microns channel is presented. The amounts of NO2, NO2, O3 and the airmass were chosen to closely simulate a low sun spectral scan from a 9 February 1977 balloon flight. The solar radiance outside the earth's atmosphere was determined from the AFGL Sacramento Peak Observatory spectral data tape degraded to 2.0A resolution and normalized to Thekaekara's absolute intensities. The spectral absorption coefficients used for NO2 and O3 were tabulated previously.

Goldman, A.↗