1997 Fiscal Year Final Research Report Summary
Evaluation of capillary radii in wood by the centrifugal method.
| Project/Area Number |
08456089
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
林産学
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| Research Institution | EHIME UNIVERSITY |
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Principal Investigator |
HAYASHI Kazuo EHIME UNIVERSITY College of Agriculture, Professor, 農学部, 教授 (80111839)
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| Project Period (FY) |
1996 – 1997
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| Keywords | CENTRIFUGAL FORCE / WATER POTENTIAL / MENISCUS / CAPILLARY RADIUS / FLOW IN WOOD / ASPIRATED BORDERED PIT PAIRS / PERMEABILITY / DAMAGE OF TORUS / CONTACT ANGLE |
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| Research Abstract |
1.The size distribution of free water paths for six species of softwood was estimated by centrifugal method which is a new method developed from the balance of water potential decreased by centrifugal force and capillary pressure by meniscus and the amount of dehydrated free water by centrifugal force. The distribution depends on species and the location in wood. For example, the radius in earlywood was larger than one in latewood. This result was presumed to be the feature for undried wood as there was the contrary result for dried sample.
2.The change of effective radius of free water paths by local steam explosion was obtained quantitatively by the centrifugal method.
3.The damage of pits by the centrifugal force was easier in sapwood than in heartwood because of the strength of adhesion between pit border and torus. Pits in Sugi damaged easier than those indouglas fir because the ratio of the diameters of torus and pit aperture is larger in douglas fir than in sugi and the torus in douglas fir was supported stronger than one in sugi.
4.The force required for the damage of pits was 0.1 to 0.2 MPa for the sapwood in sugi. For the pits in heartwood larger value was estimated by centrifugal method. This means pits in wood has possibility to be damaged by capillary tension during drying.
5.The contact angle of wood was considered to be zero in wet condition so far. However it was not truth. Wettability in heartwood was poor than sapwood, but after hygroscopic thermal treatment both location showed same contact angle. This tendency was same to the alcoholbenzene extractive treatment. This mean that the existence of the extracives on cell wall affects to the wettability even the wet condition.
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