Temperature Of Sheets Research Articles

Palaeoenvironments: Temperature of the ice sheets

Palaeoenvironments: Temperature of the ice sheets

Polar ice sheets: Developments since Wegener

Wegener's expeditions pioneered many measurements that are now essential for computer modelling of ice sheets. Advances in knowledge of accumulation, thickness, temperature, crystal fabric and surface mapping of ice sheets and of impurities, gas content and isotopic ratios of ice cores from these ice sheets are outlined before computer modelling work is discussed. The value of such studies in providing large scale tests of geophysical concepts is emphasized. The paper concludes by suggesting that the drag of continental ice sheets on the top of continental blocks might be of comparable magnitude and tend to balance forces on the base of these blocks by motion of the asthenosphere. Apart from providing a possible reason for the aseismic nature of the Antarctic and Greenland land masses, the hypothesis provides a suitable link for this volume between Wegener's interest in continental ice sheets and continental drift.

On The Temperature Profile and the Age Profile in the Central Part of Cold Ice Sheets

AbstractThe generalized Glen’s lawέ = έ0Tnexp (kθ) is used to calculate die horizontal and vertical velocity profiles and from these the temperature and age profiles of cold ice sheets. It is shown that, by substituting forθa function increasing linearly with height, velocity profiles for all ice sheets are obtained which represent excellent approximations to the true ones, since, above a critical height hewhere the deviation from linearity becomes large, the influence of temperature on ice flow becomes negligible. In a comparison of the present theory with Robin’s (1955) treatment a larger temperature difference ΔTof up to 30% is obtained. Furthermore the present theory yields an age considerably increased compared with Nye’s model; e.g. more than 50% at a relative height ofh\H= 0·1.

On The Temperature Profile and the Age Profile in the Central Part of Cold Ice Sheets

AbstractThe generalized Glen’s law έ = έ0Tn exp (kθ ) is used to calculate die horizontal and vertical velocity profiles and from these the temperature and age profiles of cold ice sheets. It is shown that, by substituting for θ a function increasing linearly with height, velocity profiles for all ice sheets are obtained which represent excellent approximations to the true ones, since, above a critical height he where the deviation from linearity becomes large, the influence of temperature on ice flow becomes negligible. In a comparison of the present theory with Robin’s (1955) treatment a larger temperature difference ΔT of up to 30% is obtained. Furthermore the present theory yields an age considerably increased compared with Nye’s model; e.g. more than 50% at a relative height of h\H = 0·1.

Singularities of heat treatment of the cladded VT15 alloy

1. The optimum quenching temperature of cladded sheets of the VT15 alloy 3 mm thick is 800°C. 2. The cooling rate during quenching must be no lower than 3 deg/min. 3. Since the cladding has a certain passivating effect, the rate of phase transformations in the base metal is slowed down. 4. The areas of the metal close to the cladding layer are enriched in molybdenum and consist of undecomposed β-phase.

On the Internal Temperature and the other Phenomena During Drying of the Sheet

The internal temperature of wet sheets were measured by embedding a hair like thermojunction into pulp sheets.Above around 30% moisture content, the internal temperature indicated unexpectedly low constant values, i, e, about 40 to 70°C, corresponding to hot drying temperatures 100 to 170°C.As the moisture content decreases below 30% by drying, the internal temperature begins to rise and finally attains the same value as the drying temperature.This result might indicate that the water in the sheet consists of two kinds, one is the free water and the other is the fixed water. The above phenomena are supposed to be correlated with the anomalies observed in the shrinkagemoisture content curve and the densitymoisture content curve.