| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1986: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
To investigate the movement of sand grains splashed by raindrops and wind, a fluorescent sand tracing study was made. First, a simple fluorescent-dyeing technique was developed, and the analysis of the size distribution and specific gravity of fluorescent grains established that this dyeing does not alter movable properties of natural grains. Secondly, using these fluorescent grains, the average distance and the number of the grains which moved in the period during the rainfall were tested under an artificial rainfall system. Thirdly, using these grains, the average distance of single saltation of fluorescent grains and the relation between average moved distance and wind-blowing duration were tested under a wind tunnel. The following results were obtained. 1) The relative value between fluorescent grain size and size of sand making a sand surface is a important factor having an effect upon the distance moved during the rainfall or during the wind-blowing duration. 2) The ratio of increase of the average distance per duration decreases accordingly as the duration of rainfall or the wind-blowing duration increases. 3) The number of fluorescent grains placed in a row on a slope decreases exponentially as the duration of rainfall or the wind-blowing duration increases.
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