| 摘要 |
PROBLEM TO BE SOLVED: To accurately assess and select the place of origin of wood without depending on an experience when laminated lumber is manufactured. SOLUTION: When the laminated lumber of a specific grade is manufactured, the strength of lumber plates produced from the places of origin has a normal distribution, and the relation (a first relation) of the mean value of strength of the lumber palters in the case the ratio of the lumber plates being rejected in manufacture of the laminated lumbers of a specific grade to the laminated lumbers produced from the wood of the place of origin becomes a first specific value to the standard deviation is obtained. The relation (a second relation) of the mean value of strength of lumber platers in the case the ratio of lumber plates of at least maximum strength grade as the laminated lumber of a specific grade in the produced lumber plate is a specific value to the standard deviation is obtained. The lumber plate produced from the wood of the place of origin to be assessed is sampled, and the mean value and the standard deviation of the strength are respectively obtained. By plotting the obtained mean value and the standard deviation respectively on a chart to represent the first relation (two-dot chain line) and the second relation (solid line) respectively, the place of origin of the wood is assessed and selected.
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