Laboratory formation of border ice and frazil slush

1977 ◽  
Vol 4 (2) ◽  
pp. 153-160 ◽  
Author(s):  
T. O'D. Hanley ◽  
B. Michel

Ice formation under controlled conditions was studied in a cold room using a cylindrical steel tank 120 cm in diameter and 76 cm deep. Paddles turned by a variable speed motor moved the water about the axis of the tank. Twenty-one thermistors were used to record temperatures above and below the surface of the water. Ice was allowed to form with the cold room temperature held at −2 °C, −5 °C, −10 °C, and −20 °C and with water speeds (measured 4 cm from the tank wall) from 0 to 73 cm/s.At zero water speed ice formed first as needles randomly oriented over the surface. With flowing water, border ice width increased linearly with time, but independently of water speed. The rate of increase of the border width w fits the equation dw/dt = (4/9)|Ta|0.68 where Ta is the Celsius air temperature.Frazil was never observed at water speeds less than 24 cm/s, but was always formed at this or greater speeds, regardless of cold room temperature. The volume of slush accumulated was greater at greater water speeds and at colder air temperatures. Observed slush volumes are compared with semiempirical values of the ice mass obtained from theoretical equations. The data suggest that growth of ice crystals began when the water was supercooled by approximately 0.02 °C.

1948 ◽  
Vol 35 (1) ◽  
pp. 39-48 ◽  
Author(s):  
E. D. Smith ◽  
B. H. Ershoff ◽  
R. J. Winzler ◽  
H. J. Deuel

2013 ◽  
Vol 12 (2) ◽  
pp. 205-212
Author(s):  
Daniel Burkacki ◽  
Michał Wójcik ◽  
Robert Jankowski

In technical branches, such as chemical or petroleum industries, cylindrical steel tanks are essential structures used for storage of liquid products. Therefore, their safety and reliability is essential, because any failure might have dangerous consequences, in extreme cases may even lead to an environmental disaster. The aim of the presented paper is to show the results of the modal analysis concerning the cylindrical steel tank with self-supported roof which has been constructed in northern Poland. The investigation was carried out with the use of the FEM commercial computer program Abaqus. The values of natural frequencies, as well as the natural modes, for different levels of liquid filling (empty tank, partly filled and tank fully filled) were determined in the study. The results of the study clearly indicate that the increase in the liquid level leads to the substantial decrease in the natural frequencies of the structure.


2019 ◽  
Vol 45 (2) ◽  
pp. 85-91
Author(s):  
Kostyantyn Burak ◽  
Vitaliy Kovtun ◽  
Mary Nychvyd

The purpose of this work is to increase the accuracy, quality and information content of geodetic surveys of vertical steel tanks by using modern geodetic equipment and creating algorithms for data processing of these observations. Method. In order to increase the information content of data for straightening, it is proposed to calculate the geometric parameters of vertical steel tanks not only in places where data are directly obtained through instrumental observations, but also at any point of the 3D surface of the tank. The paper describes an algorithm for creating a 3D surface of a tank by bicubic spline interpolation (BSI). Results on the basis of the conducted research, it was established that the developed algorithm could be used and the 3D-surface spatial coordinates were determined. The method of determining the geometric parameters of vertical steel tanks by using BSI is improved. Scientific novelty and practical significance. Bicubic spline interpolation (BSI) was used for the first time. It greatly increases the accuracy and informality of the results of the control. The practical significance is confirmed by the control of the geometric parameters of a vertical cylindrical steel tank with a nominal capacity of 75.000 m3 with a floating roof and a double wall of the LODS “Brody” company.


1977 ◽  
Vol 42 (2) ◽  
pp. 295-299 ◽  
Author(s):  
J. D. Hamilton ◽  
E. W. Pfeiffer

Black-tailed prairie dogs (Cynomys ludovicianus) were deprived of food and water for several weeks during the fall and winter in a cold-room hibernaculum (Ta 5–8 degrees C), and for several days at room temperature during the summer. Body temperatures (Tb) were determined periodically in nine animals by radiotransmitters implanted in the abdomen. Animals deprived of food and water in the summer were killed when maximum urine concentration was achieved. Eight animals in the winter were active when killed after 7–35 days in the hibernaculum with Tb between 18 and 36 degrees C. Five animals that became torpid periodically in the winter were killed after 19–42 days in the hibernaculum when their Tb indicated torpor (Tb less than 13 degrees C). Active animals in the summer and winter possessed pronounced renal corticomedullary urea and sodium concentration gradients. Torpid animals lacked these gradients and had lower urine and plasma osmotic concentrations than active animals. Plasma urea values and terminal osmolal U/P ratios were lowest in torpid prairie dogs.


1963 ◽  
Vol 205 (5) ◽  
pp. 905-908 ◽  
Author(s):  
Joan Baumber ◽  
Arliss Denyes

Incorporation of C14 from acetate-1-C14 into lipid and CO2 by epididymal fat from golden hamsters kept at room temperature, acclimated to 5 ± 1 C, in hibernation and arousing from hibernation, was measured in vitro at 37 C. Summer and winter series were compared. The C14O2 production by tissue from control and acclimated animals was similar but the C14O2 production of tissue from hibernating and arousing hamsters was significantly greater than that from acclimated animals. There was a large increase in the lipid-C14 of tissue from cold-acclimated animals and this increase persisted into hibernation but was slightly depressed in tissue from arousing animals. Many acclimated and all hibernating hamsters had involuted testes and a greater incorporation of C14 into lipid than those with noninvoluted testes. A greater percentage of hamsters hibernated in the cold room during the winter and at this time the incorporation of C14 into lipid by the fat pad was greater than in the summer.


1962 ◽  
Vol 17 (2) ◽  
pp. 311-316 ◽  
Author(s):  
F. N. Craig ◽  
E. G. Cummings

For two men walking on a treadmill and wearing two layers of permeable clothing, the same physiological strain measured by the rate of increase in mean body temperature could be produced a) next to a building outdoors in the sunshine with an average air temperature of 85 F and humidity of 20 mm Hg and b) indoors with the same humidity and an air temperature 10 F higher. Under these conditions, the underwear was mainly wet with sweat and the outer layer was mainly dry. In comparable indoor tests on a third subject, the temperature of the underwear approached equilibrium 1 or 2 F lower than the temperature of the skin at air temperatures of 85 and 115 F. The error in calculating clothing insulation introduced by assuming the clothing to be dry is determined by the size and direction of the temperature gradient between skin and air. Adding 10 F to the indoor air temperature does not duplicate all the effects of sunshine. Submitted on September 15, 1961


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