有用樹種別收縮現象の特異性に関する研究(予報)

J-STAGE

書誌事項

タイトル別名
  • Studies on the shrinkage of important timbers. (Preparator report)

抄録

A comparison of the rate of shrinkage for the various woods has been made by the measurement of shrinkage amount when some moisture contents were changed. The purpose of the present paper is to present the connection between shrinkage percent and the elapsed times of drying and a comparison among ten important species of Japanese timbers. The blocks used in the experiment, 6 by 6 by 30mm. in size, were sawed from completely air seasoned timbers. The history of the materials from which the blocks were obtained was not known from the time on which the trees were fallen til the woods were used. Then the blocks were soaked into the water until the maximum absorption water was obtained. When the blocks were saturated, they were removed from the water, and then placed in a desiccator maintained at a temperature of 40°C, and a relative humidity of 0.0 percent. The transformation of tangential and radial dimension were measured at the continuous time.<br> The results of this experiment are as follows.<br> A) The increase of shrinkage percent during the drying period is very slack at the beginning, hasty at the next stage and very slack at the end stage.<br> B) All species begin to shrink at 10_??_30 minutes elapsed, and in tangentialdirection, as usual, it begins to shrink earler than in radial, but it is contrary in few timbers.<br> C) Akamatsu, Sugi, Buna and Nire show great shrinkage in an early time. Hiba, Nara, and Hoo show this little transformation.<br> D) It is very hard to observe correctly the end point of shrinkage, but will be able to say, as a rough comparison, that Katsura, Buna, Nara Nire and Sen stope to shrink early, but Hiba and Hoo lately. It is conspicuous charactor to continue the shrinkage of radial direction among very long period, in Buna and Nara.<br> E) The maximum shrinkage percent was appeared in Buna (tangential direction) and Sen (radial direction), and minimum one in Sen (tangential direction) and Hiba (radial direction). Especially Hoo has a small shrinkage in both two directions.<br> The connection between the elapsed times and the ratio (T/R), Where T; tangential shrinkage, R; radial shrinkage. was divided in to the next four groups, 1) Akamatsu, Sugi, Hiba and Katsura, 2) Sen and Nara, 3) Buna, Keyaki and Nire, 4) Hoo.<br> Hiba, Buna and Nara have a large ratio (T/R) and Sen, Katsura and Keyaki have a small one.

収録刊行物

  • 日本林學會誌

    日本林學會誌 37 (9), 396-401, 1955

    THE JAPANESE FORESTRY SOCIETY

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