>When considering the effects of charring on deformation of charcoal, it
>may be as well to consider the biochemistry of the reaction. Wood is
>largely made up of cellulose together with lignin and hemicelluloses, each
>of which will react to thermal degradation differently. The proportions of
>these constituents presumably vary according to species, and also
>according to the state of the wood. For example, green wood is likely to
>have a higher hemicellulose content. The thermal degradation process will
>also be affected by the presence of water. If a greater understanding of
>the biochemistry of the reaction is available for given wood species, then
>it may be possible to predict the ancient conditions of heating, and thus
>obtain further insights into ancient technologies.
For a useful not-too-technical discussion of the biochemistry of cellulose,
see:
http://www.fibersource.com/f-tutor/cellulose.htm
Note the short section on thermal degradation and the production of tars
under certain conditions.
Delwen
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Dr. Delwen Samuel
Institute of Archaeology Division of Life Sciences
University College London Franklin-Wilkins Building
31-34 Gordon Square King's College London
London 150 Stamford St.
WC1H 0PY London
SE1 9NN
[log in to unmask] Tel: (0) 20 7848-4232
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