Journal of the Japanese Society of Snow and Ice

A domestic labour survey was carried out for snow removal from a passage between garage and front-gate at the author's home in a winter of 1966-67. Severe snow storms occured in that winter enabled to take data in comparatively wider range of the depth of new snow. The time (t in min.) required for one man to remove snow from about 50 m² was found to be related with the depth of new snow (d in cm) in such a linear regression as follows,
t=10. 6+1. 53d.
Properties of snow, density, hardness and water content did not affect much to the time as far as the work was done with new snow, but removal of hard snow deposited at the gate by public snowploughs was time consuming. A comparative survey was carried out on various home equipments for snow removal used in Hokkaido. Usefulness of the bamboo snowshovel was emphasized.

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The frictional charge of ices of polycrystalline and single crystal was measmed.
The ice probes were of cylindrical rod and they were rubbed asymmetrically together.
In other wards, the rubbing point of an ice rod was constant and that of anther probe was variable during the rubbing.
In this rubbing, the former ice rod with the constant rubbing point became warmer than the latter ice rod with variable rubbing point.
As a result, the following results were obtained.
1. When the warmer ice rod of polycrystal was positively electrified and the colder ice rod of single crystal negatively electrified.
2. When the colder ice rod of polycrystal was rubbed with the warmer ice rod of single crystal, in the begnning of the rubbing experiment the former was positively electrified and the latter was negatively electrified.
This sign of frictional charge was the same as in 1
However, when the rubbing was continued, the sign of electrification changed to the opposite or the amount of electric charge was decreased to near zero.
At this time after the change in sign the structure of surface of the constant rubbing point (warmer ice) in single ice changed from single crystal to polycrystalline. The size of cell boundaries of polycrystals which was newly produce by rubbing at the rubbing point was as small as one tenth of the original polycrystal ice rod.
From the observational results it was concluded that the ice of polycrystalline was always electrified positive when it was rubbed with the ice of the single crystal, in spite of temperature difference.
In other words, the effect of the difference in the crystal property of ice probe that is, whether polycrystal or single crystal.

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