Clean Snow Research Articles

Mechanized cleaning of railroad cars

Scrap-breaking shop No. 1 at the Magnitogorsk Metallurgical Combine has made and put into service two self-propelled units of a new design for the mechanized removal of debris and nonmagnetic materials from gondola cars. Use of the units has completely eliminated manual labor formally required to close the hatches, remove debris and pieces of nonmagnetic materials, and clean dirt and snow from the sides of the cars. The unit is equipped with a dust-suppressing device and a hoisting telpher to lift its components when it, itself, is being repaired. It is operated from a cab and is relatively quiet when in use. It can handle 250 gondolas a day.

Red Earth: Revolution in a Sichuan Village.

Part 1 Social and economic change: back to the beginning ancestral memories - before 1950 A Clean Snow Sweeps the Land - land reform in 1951 taking the co-operative road - 1953-7 how high the cost of fighting Paper Tigers: - 1958 great leap forward - triumph and tragedy - 1958-61 the people's commune - 1962-72 walking on two legs - 1972-82. Part 2 Ideological and political change: passing the gate - 1966 the cultural revolution - 1966-76 family farming once again - after 1982. Part 3 Cultural change: barefoot doctors - the village clinic part-work, part-study - the school the politics of women's emancipation festivals and life-cycle celebrations. Epilogue.

Water requirements of captive reindeer hinds with artificial feeding

Winter (February to April) water re­ quirements of 40 reindeer (Rangifer tarandus ta- randus L) were studied at the Kaamanen Re­ search Station (69°10'N) (Soppela et al 1987). In 1985 28 hinds were divided into four groups and fed with equal rations of (I) lichens (Cladi- na spp.) with 3% crude protein (CP): (II) li­ chens and dry hay (Phleum pratense) with 12% CP, (III) pelleted reindeer feed with medium (12%) CP and (IV) pelleted feed with high (17%) CP. The study was done with 12 hinds (feeding I and II) in 1986. The hinds were kept in outdoor enclosures, where clean snow was available ad libitum for free water intake. The animals were weighed monthly. Total body wa­ ter (TBW) and daily water turnover (WTR) was measured by the tritiated water method (Holle- man et al 1982). Total body fat (TBF) was cal­ culated from TBW according to Pace and Rathbun (1945). Drinking water intake was measured indirectly by subtracting the intake of feed water and metabolic water from the daily water influx or WTR. The amount of energy re­ quired to melt and warm the drinking water to body temperature (39°C) was calculated from the specific heat values of water, snow or ice at different ambient temperatures. Total body water remained unchanged (mean TBW 68.8±0.7%) in each group from February to March. Body weight decreased in all groups except for hinds fed with high protein feed (Group IV). Total body fat decreased from 6.9 to 3.0% in hinds fed with hay and lichens from February to March (P<0.05). Mean TBW in- April. In April, hinds fed with lichens (Group I) weighed less and had a higher TBW (74.6 to 68.8%) than hinds fed with medium protein feed (Group III) (P<0.01), whereas their (Gro­ up I) TBF was smaller (0.3 to 6.1%, P<0.01). The mean daily water turnover was smaller in February in hinds fed with lichens (Group I) or with hay and lichens (Group II) than other gro­ ups of hinds. The mean daily WTR remained unchanged from February to March in Group I hinds but increased in the others. The mean dai­ ly WTR in Group I increased slightly from March to April, but was still smaller than in other groups. There was a strong positive corre­ lation between the intake of digestible CP and WTR (r=0.738, n=35, P<0.001). Daily drinking water intake was smallest (P<0.001) in the lichen-fed hinds (Group I) throughout the feeding period. It was rather constant in this group, while it increased in other groups from February to March. The li­ chen group drank 0.11/day in March. Groups II, III and IV drank 2.0, 3.2 and 3.5 1/day respecti­ vely. In April drinking water intake was smaller in Group I than in Group III (0.1 and 3.7 1/day resectively) (P<0.001). The energy costs of melting and warming drinking water were smal­ lest in the lichen-fed hinds in each month during the trial (mean 0.1 MJ/day), while hinds fed with pelleted feeds had the largest energy costs. Hinds fed with hay and lichens (Group II) had energy costs of 0.5 MJ/day in February and 1.2 MJ/day in March. The energy costs of hinds fed

Mode of Formation of “Ablation Hollows” Controlled by Dirt Content of Snow

AbstractA contradiction has existed in the literature as to the conditions favoring formation of “ablation hollows” (“suncups”) on a melting snow surface. Some experiments find that these features grow under direct sunlight and decay in overcast, windy weather; whereas others find just the opposite result, that they grow best under cloudy, windy conditions and decay if exposed to direct sunlight. We find that the hidden variable in past experiments, which acts as a switch to determine which mode of formation can operate, is the absence or abundance of dark insoluble impurities in the snow. Direct sunlight causes ablation hollows to grow in clean snow and to decay in dirty snow (for dirt content below a critical value), because the dirt migrates to the ridges between the hollows, lowering the albedo at the ridges. By contrast, when ablation is dominated by turbulent heat exchange, the presence of dirt favours development of ablation hollows because the dirt migrates to the ridges and insulates them; albedo reduction has a negligible effect on ablation.This hypothesis is supported by an experiment which showed that the presence of a thin layer of volcanic ash on the snow inhibited formation of ablation hollows under direct sunlight.

Mode of Formation of “Ablation Hollows” Controlled by Dirt Content of Snow

AbstractA contradiction has existed in the literature as to the conditions favoring formation of “ablation hollows” (“suncups”) on a melting snow surface. Some experiments find that these features grow under direct sunlight and decay in overcast, windy weather; whereas others find just the opposite result, that they grow best under cloudy, windy conditions and decay if exposed to direct sunlight. We find that the hidden variable in past experiments, which acts as a switch to determine which mode of formation can operate, is the absence or abundance of dark insoluble impurities in the snow. Direct sunlight causes ablation hollows to grow in clean snow and to decay in dirty snow (for dirt content below a critical value), because the dirt migrates to the ridges between the hollows, lowering the albedo at the ridges. By contrast, when ablation is dominated by turbulent heat exchange, the presence of dirt favours development of ablation hollows because the dirt migrates to the ridges and insulates them; albedo reduction has a negligible effect on ablation.This hypothesis is supported by an experiment which showed that the presence of a thin layer of volcanic ash on the snow inhibited formation of ablation hollows under direct sunlight.

The Detection of Zinc Sulfide in Melted Snow Samples

A modern Becquerel phosphososcope has been constructed for detecting zinc sulfide tracer in melted snow samples. The device utilizes the components of the real-time sensor described by Nickola et al., adapted to a rotating shutter unit. Commercially available fluidized zinc sulfide powder has been found adequate for storm work when ultraviolet radiation is almost eliminated by cloud cover. The dependence of the light output of the pigment on temperature was found to be negligible at room temperature. An absolute calibration of light output vs. mass concentration of pigment has not been performed; results are expressed as voltage developed by the photomultiplier sensor. Field trials have shown that the instrument is very useful for detecting differences in pigment concentration from time-to-time and place-to-place. The background signal from a test tube of distilled water is 5 mV. Samples of clean snow and stream water produce a signal of 5–8mV. When the tracer is dispersed, the signals found in samples of the snow-pack vary from near background to several hundred millivolts at a distance of 8 mi from the dispersing site, to as high as 70 V in the immediate vicinity of the dispenser.

Electrical Conductivity of River, Rain and Snow Water

“THE DATA OF GEOCHEMISTRY”, by the late F. W. Clarke, is a mine of information on river waters, their variation with geological formation and Joly's 'cyclic sodium' transported in the air and brought down by rain. These phenomena are simply studied by measurements of electrical conductivity at 0° C. Thus C × 106 for Plymouth tap-water varied during 1923–24 from 25 to 28 ; the values found on July 7, 1923, and September 26, 1923, were 27 and 28—identical respectively with those of July 5, 1945, and September 19, 1945. The pH varied from 6·4 to 6·8 during the year. It was with some surprise that I found rain-water, collected at Downderry on the Cornish coast during a downpour on March 12, 1946, to have a conductivity 24, with pH. 6·6. Rain at Plymouth on March 13, 1946, had conductivity 55 and pH 4·0. During the night of September 19–20, 1946, rain at Antony, Cornwall, had conductivity 28, the typical September figure for Dartmoor water. Clean snow at Downderry on January 24, 1947, gave 44, and a Plymouth sample of January 25, 1947, gave 72 for conductivity. The latter was taken from the middle of the snow blanket and was, on thawing, surprisingly sooty. Plymouth rain of January 8, 1947, had conductivity 70, close to that of snow.