CONTRIBUTION TO THE THEORY OF CELL COLLAPSE IN WOOD: INVESTIGATIONS WITH EUCALYPTUS REGNANS
Total collapse is considered as the sum of "liquid tension collapse" and "stress collapse". An equation is derived giving total collapse as a linear function of wood temperature and, to a smaller extent, of collapse-free shrinkage. The parameters of the equation depend only on su...
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| Autor principal: | |
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| Lenguaje: | English |
| Publicado: |
Universidad del Bío-Bío
2002
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| Acceso en línea: | http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-221X2002000100007 |
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| Sumario: | Total collapse is considered as the sum of "liquid tension collapse" and "stress collapse". An equation is derived giving total collapse as a linear function of wood temperature and, to a smaller extent, of collapse-free shrinkage. The parameters of the equation depend only on surface tension data and on structural and rheological properties of the wood. To test the theory, Eucalyptus regnans cubes of 7/8 in. edge length were dried at temperatures ranging from 70 to 285°F, using two levels of humidity at each temperature. In addition, specimens measuring 7/8 by 7/8 by 3 in. were dried at 150°F and low humidity. The results show good agreement with theoretical values for wood temperatures up to about 190°F. For higher temperatures or very low humidities collapse is found to be significantly time-dependent. Collapse in small end-sealed cubes is shown to be of the same order as that in the thickness of boards of rectangular cross section, but the latter collapse less in width |
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