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Volume 31, Issue 1
Displaying 1-4 of 4 articles from this issue
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Hisashi SHIO, Choji MAGONO1969 Volume 31 Issue 1 Pages 1-6
Published: January 30, 1969
Released on J-STAGE: July 23, 2009
JOURNAL FREE ACCESSIt is known that when two pieces of ice rods were rubbed asymmetrically, the colder ice rod with the variable rubbing point is electrified positively, and the other warmer ice rod with the constant rubbing point is electrified negatively. And this observational fact is generally understood to be caused by the temperature difference in the two ice rods, namely the colder ice with the variable rubbing point and the warmer ice with the constant rubbing point.
However as reported by the authors in the previous article, it was found that when a polycrystal ice rod was rubbed with a single crystal ice rod, the polycrystal ice was electrified positively regardless of the temperature difference. Accordingly, it seemed that the difference in the crystal character fact was more effective than the temperature difference on the frictional electrification.
Therefore as the next step of the experiment, the authors noted the effect of difference in crystal axes on the frictional electrification, and they prepared the basal plane and the prism plane of ice. The frictional experiment was carried out at the temperature range of-10°C-21°C in a colder chamber of the Institute of Low Temperature Science. The results of the experiment obtained are as follows.
1) When two ice surfaces with the same crystal planes, asymmetrically the ice of the warmer surface was always electrified negatively, as expected from the thermoelectricity.
2) The ice surface of the prism plane was rubbed with the ice surface of basal plane, the former was electrified positively unregardless of temperature difference.
3) When the rubbing of ice surfaces with difference crystal axes were continued for several hundred seconds, the sign of electrification was reversed. This perhaps was caused by the change in the rubbing surface.
From the experimented results, it was concluded that the ice surface of prism plane was charged positively when it was rubbed with the ice surface of basal plane, and the effect by the difference in the crystal axis is stronger than that by the temnerature difference.View full abstractDownload PDF (8503K) -
Tokuo IMAI1969 Volume 31 Issue 1 Pages 7-13
Published: January 30, 1969
Released on J-STAGE: July 23, 2009
JOURNAL FREE ACCESSTo know well of the quantity of drifting snow in the snow fallen district is one of the important elements for the good design of the equipments which protect railroads and the highways from the snowstorm.
An adequate measure of snowstorm is progressive in Soviet Union. The quantity of drifting snow was calculated according to the various formula, being expressed as the function of wind velocity over the snow cover.
In this report was utilized the formula Qmax=0.0215 V3g/m·sec (where 0.0215 is numerical value, measuring Qmax and V with g/m·sec. and m/sec. unit respectively) which was suggested by D.M.Melnik in Soviet Union.
Measured values of wind velocity and snow drift depend upon the data of Minenobu in Hokkaido in Jan-Mar 1965. Measureemnt of the snow drift was obtained experimentally from the accumulation of snow around the test fence.
Due to compare the Both of data a few of voluntariness was instituted. The result of that comparision, a ratio of the both of quantity (calculation/measurement) was 0.92 to 1.04. It is high comformity than the first expection.
If the wind velocity the temperature and the snowfall are recognized as accuracy data, and the drifting snow times are judge with accuracy, after all estimating of the quantity of drifting snow is possible, these results will be good design data.View full abstractDownload PDF (1059K) -
Masayuki ISHIKAWA, Shohei SATO, Toshitsugu KAWAGUCHI1969 Volume 31 Issue 1 Pages 14-18
Published: January 30, 1969
Released on J-STAGE: July 23, 2009
JOURNAL FREE ACCESSThe relation between the stand density or the intervals of broad-leaved trees over 5 cm in diameter, and the stability of accumulated snow in the forest estimated from the size of snow cracks at the beginning of the spring thaw was investigated on the mountain slopes in Kamabuchi, Mamurogawa town, Yamagata, in north Honshu.
It seems that the accumulated snow is stable and no avalanche occurs in forests on the slope in which the number of trees n per ha is over
n=12500 (θ-30) secθ/D2
where θ : inclination (degree)
D : diameter of tree at breast height (cm)
or the volume of the stand is over 100m3 or thereabouts under snow conditions of 1.52 m in depth.View full abstractDownload PDF (2938K) -
Masao SAEKI, Hiroo MATSUOKA1969 Volume 31 Issue 1 Pages 19-23
Published: January 30, 1969
Released on J-STAGE: July 23, 2009
JOURNAL FREE ACCESSIt was studied in the wintertime of 1967 and 1968 at the same places in Niigata prefecture, northern central Japan, that to what extent the young forest trees growing on steep slopes would be buried in snow. Summary of the findings is as follows :
1) The snow cover with the depth of three meters or so on the slopes can be stabilized when the number of trees overtopping the snow cover is about at least five hundred per hectare.
2) The trees with the height of one and a half times the depth of snow come to appear above the snow. When the height of trees reachs about twice the depth of snow cover, more than fifty per cent of the whole trees in number will appear above the snow surface. Trees of less than five centimeters in diameter breast high are scarcely found above the snow cover.
3) Tree trunks are more subject to being buried in snow with their increasing inclination. No trees, for example, with the height of five to six meters equivalent to about twice the depth of snow cover and the trunk inclination of over thirty five degrees appear above the snow.View full abstractDownload PDF (3206K)
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