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  • 1
    Electronic Resource
    Electronic Resource
    Enhancements of CO and O3 from burnings in sugar cane fields (1991)
    Springer
    Journal of atmospheric chemistry 12 (1991), S. 87-102 
    Details
    ISSN: 1573-0662
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The manual harvest of sugar cane requires the burning of its foliage. This burning has strongly increased in Brazil after the National Alcohol Program was started which substituted automobile gasoline engines for alcohol engines. Presently, the source strength per unit area of this rural pollution is comparable to the well-known biomass burning source in Amazonia. The observed concentrations of CO and O3 in the rural area of the state of São Paulo during the 1988 burning season were twice as large as those reported from an aircraft experiment of 1985 for biomass burnings of the tropical rain forest. Results are reported from airplane measurements and from three fixed ground stations. Mixing ratios of ozone and carbon monoxide in the height range below 6 km are normally less than 40 and 100 ppbv, (parts per billion by volume), respectively, in the absence of burnings. A strong O3 and CO layer was observed during the burning period with peak concentrations of 80 ppbv of ozone and 580 ppbv of CO at about 2 km. The concentrations of CH4 and CO2 were also large, 1756 ppbv and 409 ppmv, respectively, at 1500 m. During the dry season period of the experiment, the ground based O3 average diurnal variations obtained at the rural sites were practically identical to the typical urban variation observed at São José dos Campos, with daytime ozone values between 45 and 60 ppbv. A second three-day airplane excursion to the surgar cane fields in the wet season of 1989 has produces results to be contrasted with the dry (burning) season of 1988 and 1989. Carbon monoxide concentrations were below 100 ppbv at all heights and ozone concentrations were around 30–40 ppbv. The maximum daytime concentrations at the ground station Bauru was 25 ppbv of O3, and at Jaboticabal it was 35 ppbv of O3, only one half of what was observed in the dry season.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00053935
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Determination of iridium concentration in sedimentary rocks and in the geochemical standard PCC-1 by radiochemical neutron activation analysis (1989)
    Springer
    Journal of radioanalytical and nuclear chemistry 132 (1989), S. 261-267 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A radiochemical neutron activation analysis procedure is described for the determination of concentration levels of iridium in sedimentary rocks and in the geochemical standard PCC-1. After irradiation, the powdered rock samples and standard are dissolved with a mixture of HF, HNO3 and HClO4 in a teflon bomb. The final solution obtained, in dilute HCl, is passed through a column containing the cationic resin Bio Rad AG 50W-X8. The interfening radionuclides are sorbed by the resin. The effluent solution containing iridium is concentrated for counting by evaporation. Experiments with radioactive tracer for checking radiochemical separation yield are carried out. The accuracy of the method is evaluated by means of analysis of the USGS “standard rock” peridotite, PCC-1. The precision is about 25% in the ppb range. The method is used for the determination of iridium in 16 samples of sedimentary rocks collected at different depths in the “Campos” basin-RJ (BRAZIL).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02136085
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Trace element determination in aerosols from the Antarctic Peninsula by neutron activation analysis (1992)
    Springer
    Journal of radioanalytical and nuclear chemistry 159 (1992), S. 21-28 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The knowledge of the composition of atmospheric aerosols in remote areas, like the Antarctic Peninsula is of great importance for the study of long-range transport of atmospheric contaminants and also from the climatological point of view. Instrumental neutron activation analysis was applied in the present work to determine the elements Al, V, Mn, Na, Cl, Ca, Au, Br, Sb, Sc, Fe, Zn, K, Th and La in aerosol samples collected in the Brazilian Antarctic Station “Comandante Ferraz” (62° S, 58° W) located on King George Island in the Antarctic Peninsula. The sources of the aerosols were investigated by means of Enrichment Factors and Principal Factor Analysis. Both methods yielded similar results. Sea and soil were identified as the major sources of aerosols, in the samples collected at the Brazilian Station.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02041013
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    Paper (German National Licenses)
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