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  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Thermochimica Acta 103 (1986), S. 57-62 
    ISSN: 0040-6031
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
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    Unknown
    Woodstock, Md., etc : Periodicals Archive Online (PAO)
    Theological Studies. 52:2 (1991:June) 355 
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  • 3
    ISSN: 1573-0662
    Keywords: arctic air pollution ; precursor substances ; vertical profiles ; ozone ; PAN ; SO2 ; gaseous HNO3 ; particulate nitrate ; sulfate ; ammonium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract During two measuring campaigns in early spring 1994 and 1995 (March/April) and one campaign in summer 1994, measurements of ozone, PAN, sulfur dioxide, nitric acid, and particulate nitrate, sulfate, and ammonium (only 1995) were recorded in the Arctic. Observations were made by aircraft at various sites in the eastern and western Arctic. Ozone concentrations showed a steady increase with altitude both in spring and summer. During five flights in springtime, low ozone events (LOEs) could be observed near the surface and up to altitudes of 2000 m. SO2 background concentrations, ranging from detection limit (0.5 nmol/m3) to 5 nmol/m3, were observed during both spring and summer. Distinct maxima up to 55 nmol/m3 in lower altitudes were only obtained in springtime. Concentrations of the organic nitrate PAN were within a similar range as those of the inorganic nitrate HNO3 during spring campaigns. In contrast, concentrations of particulate nitrate were one half an order of magnitude lower. HNO3 concentrations increased significantly with altitude. Evidently, HNO3 was intruded from the stratosphere into the troposphere. Sulfate concentrations ranged between 5 and 30 nmol/m3; ammonium concentrations were obtained within a range from 10 to 50 nmol/m3.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-0662
    Keywords: reduced sulfur compounds ; ambient concentrations ; gas exchange ; anthropogenic emissions ; natural emissions ; local budget ; Brazil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Extensive ambient concentration and flux measurements have been performed in the heavily polluted region of Cubatão/Brazil. Substantial contribution of anthropogenic sources to the local reduced sulfur burden has been observed. As a result of this atmospheric sulfur burden average gas exchange between vegetated soils and the atmosphere shows net deposition. Based mainly on own field measurements a local budget for H2S, COS, and CS2 has been made up in order to calculate anthropogenic emissions. All major sources and sinks in the chosen atmospheric reservoir (24×20×1 km) have been taken into account. Due to the small reservoir size fluxes across its boundaries are dominant sources and sinks. The differences between outflux and influx therefore account for the unknown anthropogenic emissions which have been determined to be 80±10 (H2S), 66±15 (COS), and 29±6 Mmol year-1 (CS2). Other sources and sinks like natural emissions, chemical conversion, and dry deposition turned out to be of minor importance on a local scale. In fact, inside the investigated reservoir natural emissions were below 0.5% of anthropogenic emissions. Anthropogenic emissions of H2S, COS, and CS2 quantified in this work have been compared with global emission estimates for these compounds made by other authors. We conclude that global anthropogenic emissions of reduced sulfur compounds especially of COS and CS2 are currently under-estimated.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-0662
    Keywords: Enzyme fluorometry ; peroxyoxalate chemiluminescence ; hydrogen peroxide analysis ; comparative study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract During September 25 to October 28, 1985, the enzyme fluorometric (Lazrus et al., 1985) and the peroxyoxalate chemiluminescence (Klockow and Jacob, 1986; Jaeschke, 1986) techniques for analyzing H2O2 were compared in laboratory studies at the National Center for Atmospheric Research in Boulder, Colorado, U.S.A. and under field conditions at the Whiteface Mt. field station of the Atmospheric Sciences Research Center, Albany, New York, U.S.A. Both methods showed excellent agreement, with a maximum deviation of ±5%. Only at unusually high concentrations of some potential atmospheric species could slight interferences be observed. During the experiments the detection limits were 1.3×10-8 mol/l (0.44 ppbm) of H2O2 for the fluorometric instrument and 4×10-8 mol/l (1.36 ppbm) of H2O2 for the chemiluminescence instrument. For the chemiluminescence technique, the response to methylhydroperoxide was approximately 80-fold less than that to an equivalent concentration of H2O2.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of atmospheric chemistry 1 (1984), S. 111-123 
    ISSN: 1573-0662
    Keywords: Sulfur gases ; marine atmosphere ; diurnal variations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Concentrations of sulfur gases H2S and SO2 have been measured in the marine atmosphere over the Atlantic Ocean at various sites. Mean values of 40 ng H2S m-3 STP and 209 ng SO2 m-3 STP are the results of the measurements. A diurnal variation of H2S concentration was detected on the west coast of Ireland with nighttime concentrations of up to 200 ng H2S m-3 STP and values below detection limit (15 ng H2S m-3 STP) during daytime.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-0662
    Keywords: orographic clouds ; cloud chemistry and microphysics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract An overview is given of the Kleiner Feldberg cloud experiment performed from 27 October until 13 November 1990. The experiment was carried out by numerous European research groups as a joint effort within the EUROTRAC-GCE project in order to study the interaction of cloud droplets with atmospheric trace constituents. After a description of the observational site and the measurements which were performed, the general cloud formation mechanisms encountered during the experiment are discussed. Special attention is given here to the process of moist adiabatic lifting. Furthermore, an overview is given regarding the pollutant levels in the gas phase, the particulate and the liquid phase, and some major findings are presented with respect to the experimental objectives. Finally, a first comparison attempts to put the results obtained during this campaign into perspective with the previous GCE field campaign in the Po Valley.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 351 (1995), S. 27-32 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A set-up for continuous measurements of atmospheric H2S concentrations in the range between 0.138 μg/m3 and 17.5 μg/m3 is described. All flows are regulated by flow sensors which are connected to the respective pump by a feed back circuit. The instrument is working in two sensitivity ranges. One is provided for low H2S concentrations (lower than 1.75 μg/m3) and the other for higher levels (higher than 1.75 μg/m3). During continuous measurements the set-up enables an automatic adaptation of one of the sensitivity ranges to ambient H2S concentrations. The critical step of absorption of gaseous H2S into the liquid phase of the continuous flow system could be stabilised by the development of a new fluid level control system. After numerous test measurements under laboratory conditions the instrument was tested for the first time in June 1993 during field measurements in the tropics. These measurements took place in the environment of natural and industrial sources of H2S in the vicinity of Salvador da Bahia in Brazil. Data are presented which prove the ability of the instrument.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 317 (1984), S. 343-344 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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