• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.612-617
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• 2007

Water meter frost in winter is a nuisance to the water administration and citizen as well. It causes stop of water supply, possibility of accident due to leakage freezing, and additional official work to change frost water meters. This study was carried out to give some basic information of water meter frost condition, to verify the effect of frost protection devices such as lagging vinyl cover, electric heater, and meter pit using subterranean heat. Nearly half of the number of the water meter frost happens in old apartment house with outer corridor, and temperature of the meter box was measured in that kind of apartment house, comparing with atmosphere temperature. The capability of three kinds of lagging vinyl cover was investigated by measuring the inside temperature of the insulated box. Also the capability of existing meter pits and new meter pits using subterranean heat was compared by measuring the inside temperature of the pits. One of the result is that the inside temperature of meter pits using subterranean heat was higher than that of the existing ones, and deeper pit causes higher inside temperature in case of using subterranean heat.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.354-361
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• 2012

This study was conducted to evaluate on the freezing tolerance of introduced blueberry cultivars in Korea and to investigate availability of portable timber moisture meter for simple and rapid diagnosis of blueberry-shoot damage by freezing during wintering. Frost tolerance of blueberry cultivars showed big difference that rates of blueberry-shoot death were widely distributed from about 0% to 100% after wintering. Optical density in TTC reduction of blueberry twig treated low temperature was low in order of $-40^{\circ}C$ < $-21^{\circ}C$ < $4^{\circ}C$. Hardiness evaluation of visible injury in the cross-sectional surface color did not agree with that of rates of blueberry-shoot death during wintering. Lowest water content of blueberry stem measured by timber moisture tester during wintering was about 15%. During wintering, water contents of blueberry stems were higher at lower part of tree, but were low at end part of stems, and then when the blueberry grew again for spring, the water content gradually increased to 20~40%. Water content of blueberry stem with freezing injury during wintering decreased to under 5% by desiccation. Therefore it is assummed that the moisture content of blueberry stem injured by freezing during wintering was about under 14%, and it is expected that portable timber moisture meter could be available for rapid diagnosis of blueberry freezing injury in field.