Study on Moisture Movement in Wood with X-ray CT scanner.

Research Project

Project/Area Number	61560189
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	林産学
Research Institution	NAGOYA University
Principal Investigator	KANAGAWA Yasushi NAGOYA University, School of Agriculture, 農学部, 助手 (90023481)
Co-Investigator(Kenkyū-buntansha)	HATTORI Yoshiaki NAGOYA University, School of Agriculture, 農学部, 助手 (80180909)
Project Period (FY)	1986 – 1987
Project Status	Completed (Fiscal Year 1987)
Budget Amount *help	¥2,400,000 (Direct Cost: ¥2,400,000) Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1986: ¥1,900,000 (Direct Cost: ¥1,900,000)
Keywords	X-ray CT scanner / Non-destructive measurement of moisture distribution / Conventional kiln drying / Radio-frequency vacuum drying / Fickの拡散則 / 水分移動の駆動力 / X線CTスキャナの応用 / 水分の非定常拡散係数
Research Abstract	Moisture distribution in drying were non-destructively detected with X-ray CT scanner. In the first stage of this research, methods were investigated to distinguish CT number attributed the moisture only from total CT number obtained directly with CT scanner and to improve the accuracy of moisture measurment using silicon rubber bags surrounding the sample. Moisture contents on internal cross section could be non-destructively measured in the finest of 1% below 40% range. In the second stage, applying the method to detect the moisture distribution of Douglas-fir thick quarter sawn lumber (6 cm thickness) in drying, change of moisture distribution in thickness direction was measured. The sample had probbably a homogeneous property for moisture movement. Also, it was assumed that the diffusion coefficient was continuously changing with moisture content. On this assumption, moisture contents on the surface of sample were reversely calculated from the relationship between diffusion coefficient and moisture content. Moisture content on the surface should be set the higher value of about 6% in high moisture content range and the higher value of 3-4% in low range than equilibrium moisture contents, in solving the Fick's 2nd law with the finite difference method. Describing moisture movement with moisture content as driving force, the diffusion coefficient was almost constant with moisture content change.