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  • Inorganic, Organic and Physical Chemistry  (2)
  • Antarctica  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Ecological research 4 (1989), S. 297-307 
    ISSN: 1440-1703
    Keywords: Antarctica ; Lichen activity ; Microclimate ; Modelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract At a boulder on a hill near Casey Station, Wilkes Land, sensors for light, temperature and humidity were installed facing the four cardinal directions. The measurements lasted for about two months of the summer season 1985/86. The data recording was carried out at intervals of 6 minutes for all probes by automatic recording instruments. Data analysis was carried out with special regard to the biological effects of the parameters analyzed. These data of the microclimatic features taken from its original place of growth were used to a regression model of potential photosynthetic activity ofUsnea sphacelata, which is a characteristic species of this area. Although the individual time courses of the above mentioned parameters show long periods of favourable conditions for possible growth and metabolic processes, the combined analysis of these variables considering threshold values for metabolism shortens these time spans drastically. Thus, cross relationships within the physical descriptors and their effects on the actual values of photosynthesis as well as respiration become evident. They are illustrated by the results of models on photosynthesis and respiration ofU. sphacelata regarding the different cardinal directions.
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2019-07-10
    Description: As technologies advance in the aerospace industry, a strong desire has emerged to design more efficient, longer life, reusable liquid hydrocarbon fueled rocket engines. To achieve this goal, a more complete understanding of the thermal stability and chemical makeup of the hydrocarbon propellant is needed. Since the main fuel used in modern liquid hydrocarbon systems is RP-1, there is concern that Standard Grade RP-1 may not be a suitable propellant for future-generation rocket engines due to concern over the outdated Mil-Specification for the fuel. This current specification allows high valued limits on contaminants such as sulfur compounds, and also lacks specification of required thermal stability qualifications for the fuel. Previous studies have highlighted the detrimental effect of high levels of mercaptan sulfur content (^50 ppm) on copper rocket engine materials, but the fuel itself has not been studied. While the role of sulfur in other fuels (e.g., aviation, diesel, and automotive fuels) has been extensively studied, little has been reported on the effects of sulfur levels in rocket fuels. Lower RP-1 sulfur concentrations need to be evaluated and an acceptable sulfur limit established before RP-1 can be recommended for use as the propellant for future launch vehicles. (5 tables, 8 figures, 9 refs.)
    Keywords: Inorganic, Organic and Physical Chemistry
    Type: AD-A426348
    Format: application/pdf
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  • 3
    Publication Date: 2019-07-13
    Description: (3'NH)- and (2'NH)-TNA, two isomeric phosphoramidate analogues of TNA (alpha-threofuranosyl-(3'-2') oligonucleotides), are shown to be efficient Watson-Crick base-pairing systems and to undergo intersystem crosspairing with TNA, RNA, and DNA.
    Keywords: Inorganic, Organic and Physical Chemistry
    Type: Organic Letters; 4; 8; 1279-1282
    Format: text
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