Quick sand

However, if sand becomes saturated with water (that is, its pores become completely water-filled as they are in quick sand), then the sand will flow in a process known as lateral spreading. Water-saturated sand flows because the weight of the sand is supported (at least temporarily) by the water, and so the grains are not continuously in contact. Apparently then, the slope of a pile of sand is dependent on water content, and either too little or too much water lowers the stable slope. This illustrates how slope stability is a function of water content. 

The features and benefits of recirculation method at water processing can be demonstrated by taking as an example the sand filter. Traditionally, to be effective, sand filter should have the height of sand bed to be 0.7-2.0 m, flow rates in slow sand Alters should be between 0.1 and 0.2 m/h, and that in quick sand filters should be between 5 and 20 m/h. 

The water jet at the bottom of the vibro-flot is turned on and creates a quick sand condition in the soil allowing the vibrating probe to sink to its anticipated depth under its own weight ... 

Wood finishing Ambient/low bake Quick sanding characteristics, reduced dirt prck up, early stacking... 

Boil the mixture gently on a sand-bath for 4 hours and then decant into a conical flask and cool. Seed the cold solution if necessary with a trace of a-methylglucoside. The glucoside separates as colourless crystals. When crystallisation ceases, filter the glucoside at the pump, drain, wash quickly with a small quantity of methanol, and then recrystallise from a minimum of methanol. For this purpose methanol of good quality, but not necessarily anhydrous, should be used. The a-methylglucoside is obtained as colourless crystals, m,p. 165°. Yield, 6-7 g. 

Sand. Buckets of dry sand for fire-extinguishing should be available in the laboratory and should be strictly reserved for this purpose, and not encumbered with sand-baths, waste-paper, etc. Most fires on the bench may be quickly smothered by the ample use of sand. Sand once used for this purpose should always be thrown away afterwards, and not returned to the buckets, as it may contain appreciable quantities of inflammable, non-volatile materials e.g., nitrobenzene), and be dangerous if used a second time. 

Both cold- and warm-coating processes employ solutions of phenoHc resins. The principal process used for foundry resins is the hot-coating process. It is the fastest, least expensive, and safest process, and it requires no volatile removal. The sand is heated to 135—170°C in a muller, and soHd novolak resin in flake form is added, which melts quickly and coats the sand. A lubricant may be added at this point. After one minute of mulling, the batch is cooled by adding water, which evaporates rapidly. 

Aerobically digested sludge usually has good dewatering characteristics. When applied to sand drying beds, it drains well and redries quickly if rained upon. 

Dear Lord, the guide shouted, pointing toward the open sea. That tide s too quick. Hurry He clapped his heels to his cob, and our horses, already nervous, needed no spurs to set off after him. Like a wild herd we thundered indifferently through mud and sand, looking to and fro between the treacherous ground ahead and the thin line of gray foam that slipped toward us, silent and inexorable, faster than we could ride. 

Many minerals have been found to dissolve and precipitate in nature at dramatically different rates than they do in laboratory experiments. As first pointed out by Paces (1983) and confirmed by subsequent studies, for example, albite weathers in the field much more slowly than predicted on the basis of reaction rates measured in the laboratory. The discrepancy can be as large as four orders of magnitude (Brantley, 1992, and references therein). As we calculate in Chapter 26, furthermore, the measured reaction kinetics of quartz (SiC>2) suggest that water should quickly reach equilibrium with this mineral, even at low temperatures. Equilibrium between groundwater and quartz, however, is seldom observed, even in aquifers composed largely of quartz sand. 

Walls or roofs tend to block vision and access, trap sand, debris, and reduce ventilation so that flammable vapors are not as quickly dispersed. They may also collapse if there is an explosion or deflagration. They can therefore contribute to secondary effects by falling onto pipes an equipment that may substantially exceed damage from the original explosion or deflagration. They can also lead to a false sense of security. 

Sandy soil At the other extreme, soil with a high sand content tends to be dry and gritty. The relatively large spaces between sandy soil particles are too big to hold water, so it drains through quickly, taking plant nutrients with it. Sandy soil Is, however, easy to work and does warm up quickly In spring. 

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