Obscuring smoke agents

Obscuring Power of White Smokes. The total obscuring power, TOP, of a white smoke agent used for screening purposes, is obtained by multiplying the product of volume, in cubic ft or smoke produced per lb of material, and the reciprocal of the smoke layer, in ft, necessary to obscure the filament of a 40-watt Mazda lamp. The TOP for some white smoke agents, at low altitudes where atm constituents are plentiful, is given in Table 1... 

Properties Pale-yellowish, translucent, crystallizable solid of waxy consistency. Sp, gr, 1.82 at 20°. M. P. 44.1°. B. P. 280°. Spontaneously inflammable in air at normal temperature gives off dense white smoke, consisting of phosphorus pentoxide and phosphoric acid. The former has a very high obscuring power. White phosphorus has the greatest total obscuring power (T. 0, P.) of all smoke agents. 

Chemical agents which produce an obscuring smoke. See Titanium Tetrachloride, Silicon Tetrachloride, Chlorsulfonic Acid-Sulfur Trioxide Solution. 

A smoke agent, us its name implies, is one capable of obscuring vision in sufficient measure to afford concealment. It may incidentally burn or corrode, yet primarily it screens. 

The fuiljstances that have been successfully used as smoke agents fall into five main groups, m., smokes that owe their obscuring power to (I) particle of colloidal rr6on suspended in air (II) particles of phosphoric arid (III) sulfuric acid (IV) hydrochloric arid and (V) zinc chloride. 

On the basis of total obscuring power (T.O.P.), the smoke agents discussed above, as well as other substances that have been used sina the War for producing smoke, are arranged below in the descending order of their T.O.P. s. 

All nations are impressed with the importance of obscuring smoke ami are busily engaged in developing the superior smoke agents and in devi> -ing technical means of employing them. The rapid strides made in tliU direction during and since the World War plainly indicate the possibility of this field. 

Smoke agent, classification, 220 comparison. 240 definition, 4 future of, 247 history, 220 iiatim of. 224 obscuring K> ver, 45. 226 riN uirtMnt niH for ideal. 4x siilisiativ< s useil, 2 12 Sodiitiit, 251... 

Chemical smoke agents are used to obscure objects or areas from observation or from engagement by weapons with electro-optical control systems. They are usually not toxic in field concentrations, but may cause eye or respiratory irritation in higher concentrations. Some smokes have adverse chronic exposure effects. Other compounds with military... 

Smokes and obscurants comprise a category of materials that are not used militarily as direct chemical agents. They may, however, produce toxic injury to the airways. The particulate nature of smokes may lead to a mechanical irritation of the upper and lower airways—therefore inducing bron-chospasm in some hypersensitive individuals (eg, those with asthma). Certain smokes contain chemicals with a degree of tissue reactivity that results in damage to the airways. A discussion of obscurant smokes is followed by a discussion of certain explosion-related (oxides of nitrogen) or pyrolysis-related (perfluoroisobutylene) substances that are important in military practice. 

Sternutators Vomiting Agents Banned RCAs Herbicides Obscurant Smokes Napalm... 

Vapor Density —Regardless of whether the chemical agent is a gas or a smoke, it must ha e a vapor density greater than that of air for other-Mise, as soon as the agent is released from its container, it w ill immediatel v rise from the surface of the ground and thus lose its physiological or obscuring effect. 

Children are at greater risk than adults for many cancers. Leukemia and brain cancer account for half of all childhood cancers. The causes of these cancers are often obscure, but research has shown that in utero exposures can start the carcinogenic process that becomes fully manifest after birth. Mixtures of chemicals, most notably tobacco smoke and pesticides, are known causative childhood cancer agents. Other chemical mixtures identified as carcinogenic to children are examined in the next chapter on cancer clusters. 

National Research Council, Alternative Technologies for the Destruction of Chemical Agents and Munitions, National Academy Press, Washington, D.C., 1993. National Research Council, Review of Acute Human-Toxicity Estimates for Selected Chemical-Warfare Agents, National Academy Press, Washington, D.C., 1997. National Research Council, Toxicity of Military Smokes and Obscurants, Vol. 1, National Academy Press, Washington, D.C., 1997. 

Of this family of products, triaryl phosphates (TAP) and alkyl diaryl phosphates (ADP) are the two important categories of FR plasticizers for PVC. Trialkyl phosphates are considered too volatile for most vinyl processes, and are more commonly found in other applications, such as leveling agents or antifoam additives. In vinyl, TAP and ADP plasticizers are used to flame-retard thin films and laminates for articles such as wall covering, tarpaulins (transportation), and vinyl-coated furniture fabric. Another major application area is in vinyl for electrical insulation in wire and cable. In addition to these applications, phosphate esters are used as functional fluids for hydraulic equipment (metal industries, power generation, and aircraft hydraulic systems) and as additives in formulated lubricant systems. As flexible vinyl composites are usually defined by their additives, when formulated correctly, phosphate esters can help produce a very cost-efficient vinyl composite capable of very low smoke and flammabihty. In nearly all markets, phosphate esters are valued primarily for their FR properties, and the distinction from function and plasticization is sometimes obscured. 

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