Principles of Construction
Absorption is the process of being drawn into a (usually larger) body, or substrate, and adsorption is the process of deposition upon a surface. This can be used to remove both particulate and gaseous hazards. Although some form of reaction may take place, it is not necessary; the method may work by attractive charges, for example, if the target particles are positively charged, use a negatively charged substrate. Examples of substrates include activated carbon, and zeolites. This effect can be very simple and highly effective, for example using a damp cloth to cover the mouth and nose whilst escaping a fire. While this method can be effective at trapping particulates produced by combustion, it does not filter out harmful gases which may be toxic or which displace the oxygen required for survival.
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MCU-2/P Protective Mask on a U.S. Navy member. The filter cartridge is on the left side of the mouth, which makes it easier to aim a rifle right-handedly.
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US Navy EOD M45 gas mask system.
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Gas mask used by the French military. The filter cartridge is connected via a flexible hose.
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Greek Infantry with gas masks
Read more about this topic: Gas Mask
Famous quotes containing the words principles of, principles and/or construction:
“Indigenous to Minnesota, and almost completely ignored by its people, are the stark, unornamented, functional clusters of concrete—Minnesota’s grain elevators. These may be said to express unconsciously all the principles of modernism, being built for use only, with little regard for the tenets of esthetic design.”
—Federal Writers’ Project Of The Wor, U.S. public relief program (1935-1943)
“It is not impossible, of course, after such an administration as Roosevelt’s and after the change in method that I could not but adapt in view of my different way of looking at things, that questions should arise as to whether I should go back on the principles of the Roosevelt administration.... I have a government of limited power under a Constitution, and we have got to work out our problems on the basis of law. Now, if that is reactionary, then I am a reactionary.”
—William Howard Taft (1857–1930)
“There’s no art
To find the mind’s construction in the face:
He was a gentleman on whom I built
An absolute trust.”
—William Shakespeare (1564–1616)