ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Forest
  • Grass Pollen seasons
  • thermal decomposition
  • Springer  (5)
  • 1
    ISSN: 1432-0789
    Keywords: Key words Decomposition rate ; Forest ; Organic matter characterization ; Pastures ; Particle-size fractions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  In topsoils under forest and 7-, 12- and 17-year-old pastures, organic matter was characterized by analysing C and N distribution in particle-size fractions, the C decomposition rates of soil and particle-size fractions and by employing density-fractionation of macro-organic matter (〉150 μm). The C and N associated with clay fractions increased with increasing age of pasture. The weight (%) of macro-organic matter and its heavy fractions (〉1.37 g cm–3) also increased with increasing age of pasture. However, in a long-term incubation (100 days), these changes seemed to involve an increase in the C decomposition rate in the topsoil of the oldest pasture. Using the C decomposition rates of particle-size fractions, it appeared that silt and clay contributed differently to C decomposition in the whole soil. C associated with silt contributed to the C decomposition rate during the first 40 days of incubation, while C associated with clay contributed to C decomposition in the long-term incubation (after 40 days), especially when the clay fraction appeared to reach saturation point with respect to its ability to bind organic compounds and thus protect the soil from C loss.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-0789
    Keywords: Key words Carbon decomposition ; Forest ; Pastures ; Topsoils ; Rondônia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  The topsoils of two sites, comprising natural forest and 4- and 20-year-old pastures, respectively, were selected in Rondônia to evaluate the changes of soil organic matter due to pasture establishment. These changes were evaluated by measuring the proportions of the C and N associated with clay and silt fractions, and by the C decomposition (CD) rate of the whole topsoils and their size fractions. The topsoils studied had large proportions of C and N associated with fine fractions, especially with clay fractions. The CD rate of the silt fractions was higher than that of the clay fractions under the two forest topsoils and under the 20-year-old pasture. The CD rate of the silt fractions under forest vegetation at each site was significantly higher than that of the silt fractions under pasture vegetation at the same site. The CD of clay fractions followed the same trend as the silt fractions, showing an improvement in the stability of C associated with clay and silt fractions under pasture vegetation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of thermal analysis and calorimetry 62 (2000), S. 711-714 
    ISSN: 1572-8943
    Keywords: ergol ; monomethylhydrazine ; thermal decomposition ; vapour pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Monomethylhydrazine (MMH) (CH3)NHNH2 is currently used as fuel for spacecraft engine combustion chambers. The Aestus engine of the upper stage of Ariane 5 is fed with MMH under pressure of 16 bars. The propellant, initially at room temperature, is about 393 K when introduced into the combustion chamber, due to heating up through the regenerative circuit. As MMH is unstable above 373 K, it has been necessary to check its decomposition rate and vapor pressure under such conditions. The vapor pressure of this propellant has been measured in a pressure vessel and the thermal decomposition rate was determined with the same device up to 500 K.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of thermal analysis and calorimetry 63 (2000), S. 559-564 
    ISSN: 1572-8943
    Keywords: asymmetric dimethylhydrazine ; hydrazine monohydrate ; propellant ; thermal decomposition ; vapour pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Engine Viking of Ariane 4 is supplied with asymmetrical dimethylhydrazine (UDMH) (CH3)2NNH2. An addition of a small amount of hydrazine hydrate N2H4×H2O was proposed to increase the thermal stability of UDMH. The mixture where the mass ratio (CH3)2NNH2/N2H4×H2O is equals to 75/25, is called UH25. These propelling agents are unstable when they are heated and the optimisation of burning conditions requires a good knowledge of their vaporisation and of their thermal decomposition kinetics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1573-3025
    Keywords: aerobiology ; airborne pollen ; Europe ; European Pollen Information ; Grass Pollen seasons ; Phenology ; start dates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Geographical and temporal variations in the start dates of grass pollen seasons are described for selected sites of the European Pollen Information Service. Daily average grass pollen counts are derived from Network sites in Finland, the Netherlands, Denmark, United Kingdom, Austria, Italy and Spain, giving a broad longitudinal transect over Western Europe. The study is part of a larger project that also examines annual and regional variations in the severity, timing of the peak and duration of the grass pollen seasons. For several sites, data are available for over twenty years enabling long term trends to be discerned. The analyses show notable contrasts in the progression of the seasons annually with differing lag times occurring between southern and northern sites in various years depending on the weather conditions. The patterns identified provide some insight into geographical differences and temporal trends in the incidence of pollinosis. The paper discusses the main difficulties involved in this type of analysis and notes possibilities for using data from the European Pollen Information service to construct pan European predictive models for pollen seasons.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...