Steady-State Diffusion of Chloropicrin in Douglas-Fir Heartwood
Keywords:Diffusion, chloropicrin, fumigant, heartwood, Douglas-fir
AbstractThe effects of moisture content, flow direction, concentration, and temperature on the diffusion of chloropicrin in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) heartwood were investigated. Diffusion coefficients were strongly affected by wood moisture content. Coefficients for radial and tangential diffusion at the fiber-saturation point were twice as high as those at the oven-dry condition. Longitudinal diffusion coefficients, however, increased only 12.5% when the moisture content was increased over the same range. Longitudinal diffusion coefficients were about three orders of magnitude higher than those in the transverse directions, while there was no significant difference between radial and tangential diffusion coefficients. Diffusion coefficients were independent of concentration, showing the validity of Fick's law of diffusion in characterizing the flow of the fumigant in wood. Diffusion coefficients were always higher at 35 C than at 20 C; however, the difference was not statistically significant, suggesting that the flow of the fumigant is not a temperature-activated process.
Cooper, P. A. 1986. Selecting fumigants for treatment of internal decay in wood. International Research Group on Wood Preservation. IRG/WP/3370. 12 pp.nCooper, P. A., R. D. Graham, and R. T. Lin. 1974. Factors influencing the movement of chloropicrin vapor in wood to control decay. Wood Fiber 6(1):81-90.nDaniel, G., and B. Goodell. 1989. Cell wall microdistribution of chloropicrin and methylisothiocyanate in treated spruce. International Research Group on Wood Preservation. IRG/WP/3548. 11 pp.nGoodell, B. S., and R. D. Graham. 1983. A survey of methods used to detect and control fungal decay of wood poles in service. Int. J. Wood Preserv. 3(2):61-63.nGoodell, B. S., R. D. Graham. and R. L. Krahmer. 1980. Chloropicrin movement and fungitoxicity in a decaying southern pine laminated timber. Forest Prod. J. 30(12):39-43.nGoodell, B. S., R. D. Graham. and R. L. Krahmer. 1986. Bound chloropicrin residue in chloropicrin-treated Douglas-fir. Wood Fiber Sci. 18(1):127-133.nHighley, T. L., and W. E. Eslyn. 1982. Using fumigants to control interior decay of waterfront timbers. Forest Prod. J. 32(2):32-34.nKrahmer, R. L. 1961. Anatomical features of permeable and refractory Douglas-fir. Forest Prod. J. 11(9):439-441.nMorrell, J.J. 1989. The use of fumigants for controlling decay of wood: A review of their efficacy and safety. International Research Group on Wood Preservation. IRG/WP/3525. 18 pp.nMorrell, J.J., and M. E. Corden. 1986. Controlling wood deterioration with fumigants: A review. Forest Prod. J. 36(10):26-34.nMorrell, J.J., and T. C. Scheffer. 1985. Persistence of chloropicrin in western redcedar poles. Forest Prod. J. 35(6):63-67.nRuddick, J. N. R. 1984. Fumigant movement in Canadian wood species. International Research Group on Wood Preservation. IRG/WP/3296.nSiau, J. F. 1984. Transport processes in wood. Springer-Verlag, Berlin.nZahora, A. R., and J. J. Morrell. 1989. Diffusion and sorption of the fumigant methylisothiocyanate in Douglas-fir wood. Wood Fiber Sci. 21(1):55-66.nZahora, A. R., P. E. Humphrey, and J. J. Morrell. 1988. Preliminary modeling of methylisothiocyanate movement through Douglas-fir transmission poles. International Research Group on Wood Preservation. IRG/WP/3466.n
The copyright of an article published in Wood and Fiber Science is transferred to the Society of Wood Science and Technology (for U. S. Government employees: to the extent transferable), effective if and when the article is accepted for publication. This transfer grants the Society of Wood Science and Technology permission to republish all or any part of the article in any form, e.g., reprints for sale, microfiche, proceedings, etc. However, the authors reserve the following as set forth in the Copyright Law:
1. All proprietary rights other than copyright, such as patent rights.
2. The right to grant or refuse permission to third parties to republish all or part of the article or translations thereof. In the case of whole articles, such third parties must obtain Society of Wood Science and Technology written permission as well. However, the Society may grant rights with respect to Journal issues as a whole.
3. The right to use all or part of this article in future works of their own, such as lectures, press releases, reviews, text books, or reprint books.