Progress In Methods Of Measuring The Free Water Content Of Snow

Author(s):  
David J. Fisk
1995 ◽  
Vol 58 (5) ◽  
pp. 515-518 ◽  
Author(s):  
SUSANA SANZ ◽  
GLORIA GRADILLAS ◽  
FUENCISLA JIMENO ◽  
CONSUELO PEREZ ◽  
TERESA JUAN

Twenty-one samples from the Cantabrian coast were analyzed to establish their microbiological quality and fermentation tendency. In a food with a very low free-water content like honey, microbiological growth is only possible when there is an increase in water activity. Since most of the samples studied were not extensively granulated, the risk of fermentation is mostly due to high water content. Among our samples, only two had a water content below 17.1% (no risk of fermentation), whereas the high water activity of the rest of the samples indicates the possibility of microbial growth. In fact, four of the samples analyzed showed a moisture content over the Spanish maximum legal limit, which means a high risk of fermentation. The absence of Enterobacteriaceae, coliforms, and Escherichia coli in our samples indicates an appropriate cleanliness during extractions and handling of honey. No Salmonella or Shigella were found. The relationship between water activity and mold and yeast counts found for the honeys analyzed allowed us to divide our samples in two groups: honeys with a high or a low risk of fermentation. Changes observed during storage of the samples confirmed this classification.


1973 ◽  
Vol 12 (65) ◽  
pp. 275-289 ◽  
Author(s):  
Paul M. B. Föhn

AbstractThe daily snow melt calculated from meteorological observations is compared with detailed mass-balance measurements taking into account internal changes in density and free water content in the surface layers of a glacier snow-pack. The energy balance is calculated from measurements obtained by a meteorological station at the experimental site. In addition to the standard ablation measurements the run-off from the melting snow-pack was obtained for a few days. The snow-density profiles were measured with a portable gamma-transmission probe and the liquid-water content of snow was determined by a calorimetric method.Agreement between the melt calculated by the heat-balance method and the mass changes observed in the mass-balance measurements is fair for daily periods. It appears that about 20% of the daily snow melt takes place internally as a result of penetration of solar radiation.


1987 ◽  
Vol 26 (4) ◽  
pp. 264342 ◽  
Author(s):  
T. Hyvarinen ◽  
J. Lammasniemi

1993 ◽  
Vol 18 ◽  
pp. 117-122 ◽  
Author(s):  
Katsuhisa Kawashima ◽  
Tomomi Yamada ◽  
Gorow Wakahama

To investigate the internal structure and transformational processes from firn to ice of the Hisago snow patch on Daisetsu Mountain, Hokkaido, Japan, many drillings were made during the ablation period in 1986 and 1987. The ice cores were analyzed for stratigraphy, density and free water content. The internal structure of the snow patch was characterized by a wet firn layer with abundant ice layers and ice glands overlying a 4.3 m-thick ice body. The thickness of the firn layer varied from 12.7 m in June to 1.3 m in October. A water-saturated firn layer about 1 m thick existed just above the firn-ice transition. The annual layers were identified by dirt layers which showed that 1–2 m of ice was formed each year when the mass budget was positive. Although the densification of the water-saturated firn layer proceeded rapidly, the transformation from firn to ice could not be recognized during the ablation period. It was concluded that the formation mechanism of the ice body comprised three processes: the formation of superimposed ice, the densification of a water-saturated firn layer and the freezing of wet and/or water-saturated firn by cold wave penetration.


Author(s):  
Samuel Renjaan ◽  
Sugiatmo Kasmungin ◽  
Abdul Hamid

<p>The quality of cement is very important because it will greatly help the production well activities especially to make the construction of wells can last long. In this study the influence of lost circulation material (LCM) was analyzed, such as Bagasse, Coconut Fibers, Banana Tree Bark and Sawdust on the physical properties of G-class cement such as rheology, density, free water content, thickening time, and compressive strength. This research was conducted in the laboratory by varying the percentage of LCM from 0% to 6% and temperature from 95oF to 200oF. From this research, it can be known <br />that the addition of LCM can change the physical properties of cement. The highest increase of plastic viscosity (PV) and yield point (YP) values was occurred at 6% concentration of Bagasse, Coconut Fibers, Banana Tree Bark and Sawdust that was 105 cp – 92 lbs/100ft2, 105 cp – 90 lbs/100ft2, 90 cp – 110 lbs/100ft2, and 95 cp – 110 lbs/ft2. The longest thickening time was occurred at 6% concentration of Bagasse, Coconut Fibers, Banana Tree Bark and Sawdust with a soaking temperature of 200 oF which that was 65 minutes, 60 minutes, 66 minutes, and 63 minutes. The highest reduction of density <br />value occured at 6% concentration of Bagasse, Coconut Fibers, Banana Tree Bark and Sawdust that was 15.0 ppg, 15.2 ppg, 15.2 ppg and 15.0 ppg. The decrease in the highest free water content value occurs with the addition of 6% in each type of LCM, namely 0.9 ml, 0.95 ml, 0.9 ml and 1 ml. The increase in the strong press rate occurs in the addition of 1% sugar cane, which is 2838 psi; 1% Coconut fibre is 2926 psi, 0.5% of the banana tree bark is 3080 psi and 1% of sawdust is 2728 psi all at 200 º temperature.</p>


1977 ◽  
Vol 19 (81) ◽  
pp. 175-183 ◽  
Author(s):  
Gorow Wakahama ◽  
Atsushi Sato

AbstractWhen snow is pushed very fast by a moving body a plastic wave is generated at the head of the body. If the velocity of the moving body becomes close to that of the plastic wave, the snow may exert a great resistive force against the body as predicted by Yosida. It is, therefore, very important to study the dynamic behaviour of snow at a high rate of deformation, such as takes place when a snow plough is used on the highway, a train runs on a railroad covered with snow, or an avalanche occurs. Hence, this study is concerned with the safety and maintenance of winter traffic and transportation, and also with the generation and propagation of an avalanche. In order to clarify the detailed processes of the deformation of snow at high rates, laboratory experiments were made by compressing snow at high speed. The propagation of a plastic wave through snow was observed by using a high-speed camera and a pressure-detecting device. Analyses of the data obtained gave the velocity of the plastic wave for various kinds of snow whose density ranged from 0.17 to 0.46 Mg m-3and free-water content from o to 17%, whereby studies were made into the dependences on the density and free-water content of the velocity of the plastic wave. When the impact velocity was 4.3 ± 0.2 m s-1, the wave velocity ranged from 5 m s-1for a new snow to 12 m s-1for a fine-grained, well-settled snow. The plastic-wave velocity in wet snow was, in general, smaller than that in dry snow of the same density. Changes in density and structure of snow associated with the passage of a plastic wave were studied and discussed. The pressure at the wave front was measured; values of 0.1-0.3 bar were obtained, these are of the same order as the value estimated from theoretical formulae. The plastic-wave velocity was also observed for a confined snow, which showed a larger velocity and plastic strain than an unconfined snow.


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