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  • 1
    ISSN: 1573-1561
    Keywords: Chemosignal ; pheromone ; Asian elephant ; Elephas maximus ; temporal gland secretion ; musth ; avoiding reactions ; headspace analysis ; 2-hexanone ; 3-pentanone ; 1,5-dimethyl-6,8-dioxabicyclo[3.2.1]octane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A procedure for headspace sampling and long-term storage of organic volatiles coupled with gas chromatographic-mass spectrometric (GC-MS) analysis was used to study the volatile chemosignals in a biological secretion prior to bioassay. The approach involved collecting the volatiles in evacuated canisters from an apparatus in which 1 ml of secretion was dispersed for headspace sampling. These canisters, stainless steel, 850 ml, and 100% internally electropolished, have been demonstrated to store volatile compounds, in chemically stable form, for several weeks. The GC-MS analyses provided the quantitation and identification of compounds from C3 through C14 at concentrations as low as 0.10 parts per billion volume. The approach was used to study chemosignals of musth temporal gland secretions (TGS) from a male Asian elephant (Elephas maximus). Fresh TGS material loses its biological activity within 1 hr. TGS material stored at −20°C usually looses its activity within 30 days. The usefulness of this method for long-term storage of the volatile chemosignals was demonstrated by the retention of biologically active TGS headspace compounds, as determined through bioassays, stored in these canisters for one year.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of atmospheric chemistry 1 (1984), S. 125-135 
    ISSN: 1573-0662
    Keywords: Methane ; troposphere ; southern hemisphere ; trend ; annual cycle ; vertical gradient
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Results of more than 800 new measurements of methane (CH4) concentrations in the Southern Hemisphere troposphere (34–41° S, 130–150° E) are reported. These were obtained between September 1980 and March 1983 from the surface at Cape Grim, Tasmania, through the middle (3.5–5.5 km) to the upper troposphere (7–10 km). The concentration of CH4 increased throughout the entire troposphere over the measurement period, adding further support to the view that CH4 concentrations are currently increasing on a global scale. For data averaged vertically through the troposphere the rate of increase found was 20 ppbv/yr or 1.3%/yr at December 1981. In the surface CH4 data a seasonal cycle with a peak to peak amplitude of approximately 28 ppbv is seen, with the minimum concentration occurring in March and the maximum in September–October. A cycle with the same phase as that seen at the surface, but with a significantly decreased amplitude, is apparent in the mid troposphere but no cycle is detected in the upper tropospheric data. The phase and amplitude of the cycle are qualitatively in agreement with the concept that the major sink for methane is oxidation by hydroxyl radicals. Also presented is evidence of a positive vertical gradient in methane, with a suggestion that the magnitude of this gradient has changed over the period of measurements.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-0662
    Keywords: Methane ; troposphere ; global distribution ; trend ; seasonal cycle ; latitudinal gradient ; vertical gradient
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Methane has been measured in air samples collected at approximately weekly intervals at 23 globally distributed sites in the NOAA/GMCC cooperative flask sampling network. Sites range in latitude from 90° S to 76° N, and at most of these we report 2 years of data beginning in early 1983. All measurements have been made by gas chromatography with a flame ionization detector at the NOAA/GMCC laboratory in Boulder, Colorado. All air samples have been referenced to a single secondary standard of methane-in-air, ensuring a high degree of internal consistency in the data. The precision of measurements is estimated from replicate determinations on each sample as 0.2%. The latitudinal distribution of methane and the seasonal variation of this distribution in the marine boundary layer has been defined in great detail, including a remarkable uniformity in background levels of methane in the Southern Hemisphere. We report for the first time the observation of a complete seasonal cycle of methane at the South Pole. A significant vertical gradient is observed between a sea level and a high altitude site in Hawaii. Globally averaged background concentrations in the marine boundary layer have been calculated for the 2 year-period May 1983–April 1985 inclusive, from which we find an average increase of 12.8 ppb per year, or 0.78% per year when referenced to the globally averaged concentration (1625 ppb) at the mid-point of this period. We present evidence that there has been a slowing down in the methane growth rate.
    Type of Medium: Electronic Resource
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  • 4
    Publication Date: 2019-06-27
    Description: Nimbus energy balance computer program for satellite power systems
    Keywords: AUXILIARY SYSTEMS
    Type: NASA-TM-X-63859 , X-716-70-43
    Format: application/pdf
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  • 5
    Publication Date: 2019-06-27
    Description: Solar array electrical configurations for voltage regulation
    Keywords: AUXILIARY SYSTEMS
    Type: NASA-CR-72725 , DOC-70SD4256
    Format: application/pdf
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  • 6
    Publication Date: 2019-06-27
    Description: Computer program for solar cell performance prediction in spacecraft power supply systems
    Keywords: AUXILIARY SYSTEMS
    Type: NASA-TM-X-63709 , X-716-69-390
    Format: application/pdf
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  • 7
    Publication Date: 2019-07-13
    Description: Description of a general case solution that synthesizes a high voltage solar array system from a switchable building block concept which makes possible system optimization for specific load requirements. A specific optimized solution is demonstrated, with performance estimates relating array area, weight, and power. Significant technology problems peculiar to a high-voltage switchable solar array design are discussed, along with special requirements anticipated during a hardware development effort.
    Keywords: AUXILIARY SYSTEMS
    Type: Intersociety Energy Conversion Engineering Conference; Energy 70; Sep 21, 1970 - Sep 25, 1970; Las Vegas, NV
    Format: text
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