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  • 2000-2004  (1)
  • 1985-1989  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Soil use and management 2 (1986), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Losses of nitrogen in the tile drainflow from a clay soil (Evesham series) under grazed grassland were monitored during the 1982/83 and 1983/84 drainflow seasons. In 1982/83, 40% of the discharge had a NO3− concentration 〉 11.3 mgNl−1, while in 1983/84 concentrations were always 〉 20 mgNl−1. Total N lost by leaching was 17.5 and 48.7 kg ha−1 in 1982/83 and 1983/84 respectively, which was equivalent to 9 and 43% of the fertilizer applied. The marked difference in N losses for the two seasons was attributed to differences in the quantity and timing of N fertilizer applications, the dryness of the preceding summer and the duration and density of stocking.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of applied electrochemistry 30 (2000), S. 551-559 
    ISSN: 1572-8838
    Keywords: compressor ; fuel cell ; system operation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The performance of a system consisting of a proton exchange membrane (PEM) fuel cell coupled to a centrifugal air compressor is simulated. Two modes of operation of the system are investigated: one in which the speed of the compressor is constant, and the other in which the compressor speed is varied with the electric load on the fuel cell stack. The operating characteristics of the compressor and the PEM fuel cell stack and their influence on the system efficiency are analyzed for a step change in the stack current. The effects of the fuel cell stack back-pressure and the electric load on the compressor power consumption and the system efficiency are studied. It is found that the system efficiency is higher when the fuel cell stack is operated at a constant oxygen gas stoichiometry by varying the compressor speed instead of at a constant compressor speed. The system model can be used to determine the rotation speed of the compressor for various electric loads.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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