Edward P. Lozowski, Ryan Z. Blackmore, Tom W. Forest and John Shi, Department of Earth and Atmospheric Sciences, Department of Mechanical Engineering, University of Alberta, Alberta, Canada T6G 2E3
ABSTRACT
Newly formed marine ice accretions may include liquid brine amounts up to about 50% of the total accretion mass. Because they ignore this sponginess, traditional thermodynamic models of icing may significantly underestimate the total marine ice load. In an attempt to improve the capabilities of such models, we have undertaken experimental and theoretical research, directed at measuring and predicting the liquid fraction of ice accretions.
The experimental work consisted of growing ice accretions on rotating cylinders in the Marine Icing Wind Tunnel at the University of Alberta, over a range of temperatures from -2℃ to -25℃, and wind speeds from 10 to 30m s8, at liquid water contents (3 to 9gm -3) typical of the marine spray environment. A calorimeter was used to measure the liquid fraction of the ice accretions. The experiments indicate that the liquid fraction is almost independent of the environmental conditions and ranges between about 32% and 47%.
We have also developed a theoretical model of the morphology of the icing process which takes place under a falling supercooled liquid film. Comparisons between the model and experiments show that the model is able to predict accretion growth rate and sponginess with some degree of skill. However, there remain important aspects of the sponginess phenomenon which continue to elude us.
DEPRESSION OF SOIL MOISTURE FREEZING POINT
V.I.Fedorov, Professor, Dr.Tech.Sci, Research Institute DALNIIS, Vladivostok, Russia
ABSTRACT
Certain criteria for freezing temperature of clay soil have been found which are a relative moisture content at the soil liquid limit (W/W1) and maximum hydroscopic moisture (W/Wh).
On the strength of test data it has been established that the relative moisture content at the soil liquid limit (W/WE) may also serve as a criterion on compression pressure and resistance against shearing for soil paste with no structural binding.
Linear correlation between the moisture content of natural soil and its "paste" - the equation of moisture balance - has been found which specifies at herrnodynamic balance condition.
The equation of moisture balance represents whole set of properties for a certain type of soil, such as strength and compressibility. In this respect, it may be considered as a "Soil equation" which allows for further prognosis of its properties.
