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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 47 (1991), S. 560-572 
    ISSN: 1420-9071
    Keywords: Repository ; radioactive waste ; microbiology ; alkaline ; modelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The Nirex Safety Assessment Research Programme (NSARP) considers the effect of microbial action on the repository near field. The upper limit of growth for natural soil organisms appears to be pH 12.25. Environmental conditions in the repository will probably allow slow growth particularly on damp wastes. Experiments using packed columns of waste and concrete have shown that an extremely high pH is not conducive to rapid microbial growth. However, viable populations can exist within regions adjacent to the concrete, e.g. where a surface film coats the concrete. Carbon dioxide and methane will be produced by microbial action within the repository but actual rates of production will be lower than that in a domestic landfill. The cellulosic fraction of waste is the main determinant of cell growth. It appears to be the sugar acids arising from alkaline degradation of cellulose which cause enhanced plutonium solubility. The potentially beneficial reduction of chemically derived polyhydroxy acids by the microorganisms is possible. A mathematical model has been constructed to describe the main features of biological action in the repository.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Cellulose 7 (2000), S. 247-262 
    ISSN: 1572-882X
    Keywords: carton-board ; fatty acids ; GC/MS ; hexanal ; taint
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Unsaturated lipids exist in carton-board used for food packaging and can be the precursors of odorous compounds. The linoleic acid component may be in the form of a free acid, an alkyl ester derivative or a triglyceride. Oxidation proceeds via a free radical route to produce aldehydes, ketones, alcohols, furans, lower fatty acids, alkenes and alkanes, the majority of which are odorous. The aldehydes, in particular, have very low odour and taste detection thresholds, needing to be present only in very small amounts in a packaging material to cause a taint problem. Static headspace GC/MS analyses have identified a number of odorous compounds formed from the oxidation reactions. These oxidation reactions are affected to various extents by a number of factors that include temperature and the presence of photosensitising agents. Ultra-violet (UV) curable inks are commonly used in the printing of cellulosic carton-board packaging materials. These inks contain photoinitiators that have the potential to affect the rate and the extent of oxidation of unsaturated lipids, resulting in the formation of odorous compounds within the cellulosic carton-board matrix.
    Type of Medium: Electronic Resource
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