Principle of generating smoke

An application of the smoke generation principle described above is the smoke wire." This simulates a line source and makes it possible to efteccively study the airflow patterns in a layer, which is often desirable. A thin steel wire is... 

In an ideal situation the parameters used to define furniture should be ignition resistance and the rate of generation of heat, smoke and toxic gases. Tests to do this with actual or mock-up full sized furniture are not yet available as final specifications but the Nordtest (28) and NBS furniture calorimeters (29) represent scientific methods while room/ corridor rigs, typically UK DOE PSA FR5 and 6 of 1976 (5) (6) were originally used but are less satisfactory from a scientific point of view. The Californian (30) and Boston tests (31) for public area furniture are essentially simple room tests and are similar in principle to DOE, PSA, FR5 and 6 although the latter do not have pass/fail criteria. Bench scale rate of heat release tests include the NBS cone (29) which, with a code of practice represent a possible alternative but the rate of burning of... 

Phosphorus or metalic sodium burn in the air generating dense white smoke. The principle of smoke production is the same as the above. The reaction may occur as follows ... 

American armies gradually applied these principles to their European smoke operations. At first, the divisions of Seventh Army were more adept in the technique because of their experience in Italy. But before long the Third Army units resorted to corps area screens even more often than those of Seventh Army. Of the four armies in the European theater only the First failed to employ area screening when the occasion seemed to demand it, due in large part to a policy which kept smoke units at other tasks from which they could not be quickly relieved. On the whole, American forces in Europe learned the technique and principles of forward area screening rather quickly, especially considering the late development of the Ma generator which enhanced the possibilities of such employment. 

Precipitators are currently used for high collection efficiency on fine particles. The use of electric discharge to suppress smoke was suggested in 1828. The principle was rediscovered in 1850, and independently in 1886 and attempts were made to apply it commercially at the Dee Bank Lead Works in Great Britain. The installation was not considered a success, probably because of the cmde electrostatic generators of the day. No further developments occurred until 1906 when Frederick Gardiner Cottrell at the University of California revived interest (U.S. Pat. 895,729) in 1908. The first practical demonstration of a Cottrell precipitator occurred in a contact sulfuric acid plant at the Du Pont Hercules Works, Pinole, California, about 1907. A second installation was made at Vallejo Junction, California, for the Selby Smelting and Lead Company. 

Mechanical smoke generators came into existence through the co-operative efforts of industry, the National Defense Research Committee, and the CWS. The principle behind the device was simple. It vaporized a mixture of water and oil (the CWS used a special oil commonly referred to as fog oil), and then discharged the mixed vapors into the air. When the hot vapor hit the cool air it condensed back into tiny liquid droplets. 

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