Smoke, gray white

FIGURE 3 When magnesium burns in air, it gives off a lot of heat and light. The gray-white X>wclcry product looks like smoke. 

Gazdzinski et al, (2005) 31 36 5.5 26 Chronic smoking in alcohol-dependent individuals and in light drinkers was associated with less parietal and temporal gray matter, and more temporal white matter than in non-smokers. 

For use in trench warfare, for the purpose of obscuring the situation from the sight of the enemy, a very satisfactory dense white or gray smoke is procured by burning a mixture of zinc dust and hexachloroethane. The mixture requires a strong starting fire. The smoke consists largely of finely divided zinc chlo-... 

Uses To produce a dense white or gray smoke by burning it in combination with hexachlorethane. For a grayer smoke, naphthalene or anthracene is added to the mixture. 

Military Concealment Operations. Deliberately generated smokes are used in military situations for local visual concealment of troop operations, such as movement and placement of artillery and other fire capabilities. They may also be employed against opposing forces to cause impairment of coordinated and operational activities. Generally these are white/gray smokes. Additionally, some screens are used for infrared obscuration purposes. 

British suspended particulate sampler In recent years the old British standard method has been super-ceded by European directives such as EN12341 Air Quality - Field test procedure to demonstrate reference equivalence of sampling methods for the PMIO fraction of particulate matter. The determination of smaller size fractions (PM2.5) is also covered by a further directive. The US EPA have similar standard reference methods for particulate material (USEPA 40 CFR part 50). An early method was to simply compare the color of a filter paper through which a volume of air was drawn to an incremental gray scale (16 shades from white to black) this was then converted into an integrated particle loading with reference to the size cut-off offered by the pore size of the filter used. This was known as the black smoke index method. 

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