These separators are carefully protected by non-conducting cement and wood lagging, and are closed at the top to prevent loss of heat; and they will run for many hours without requiring to be changed, the duration of the run depending on the quality of the liquor treated and amount of impurities therein.
The cap stones should always be brought to the most accurate bed possible, with grouting used as a thin cement and not as a backer.
The safe tensile strength of Portland cement concrete would be something like one-tenth of its compressive strength, and might be far less.
The precise mechanism of the process of setting of Portland cement is not known with certainty, but it is probably analogous to that of the setting of plaster of Paris, consisting in the dissolution of the compounds produced by hydration while they are in a more soluble form, their transition to a less soluble form, the consequent supersaturation of the solution, and the deposition of the surplus of the dissolved substance in crystals which interlock and form a coherent mass.
In hand mixing it is usual to measure out from gauge boxes the sand, stones and cement or lime in a heap on a wooden platform.
Long, 27,000 tons) in the German mercantile marine, were built; and also sugar, cement and other factories.
It seems probable that the effect of the salts is inconsiderable, and that the governing condition is the temperature at which the cement has been burnt.
Down these holes cement grout was injected under high pressure on the system of Mr Kinipple.
Mastodons have fewer ridges on their molar teeth than elephants; the ridges are also less elevated, wider apart, with a thicker enamel covering, and scarcely any cement filling the space between them.
The mode of preparation is to calcine the gypsum at temperatures which depend on the class of cement to be produced.