Smoke dense

Do not stand or work in areas of dense smoke. Dense smoke can obscure energized electrical lines or equipment and can become charged and conduct electrical current. 

Boron trifluoride [7637-07-2] (trifluoroborane), BF, was first reported in 1809 by Gay-Lussac and Thenard (1) who prepared it by the reaction of boric acid and fluorspar at duU red heat. It is a colorless gas when dry, but fumes in the presence of moisture yielding a dense white smoke of irritating, pungent odor. It is widely used as an acid catalyst (2) for many types of organic reactions, especially for the production of polymer and petroleum (qv) products. The gas was first produced commercially in 1936 by the Harshaw Chemical Co. (see also Boron COMPOUNDS). 

A third screening smoke-type is white phosphoms [7723-14-0] (WP), P (see Phosphorus and THE phosphides), which reacts spontaneously with air and water vapor to produce a dense cloud of phosphoms pentoxide [1314-56-3]. An effective screen is obtained as the P2O5 hydrolyzes to form droplets of dilute phosphoric acid aerosol. WP produces smoke in great quantity, but it has certain disadvantages. Because WP has such a high heat of combustion, the smoke it produces from bulk-filled munitions has a tendency to rise in pillarlike mass. This behavior too often nullifies the screening effect, particularly in stiU air. Also, WP is very brittle, and the exploding munitions in which it is used break it into very small particles that bum rapidly. 

A solution of sulfur trioxide [7446-11-9] dissolved in chlorosulfonic acid [7990-94-5] CISO H, has been used as a smoke (U.S. designation FS) but it is not a U.S. standard agent (see Chlorosulfuric acid Sulfuric acid and sulfur trioxide). When FS is atomized in air, the sulfur trioxide evaporates from the small droplets and reacts with atmospheric moisture to form sulfuric acid vapor. This vapor condenses into minute droplets that form a dense white cloud. FS produces its effect almost instantaneously upon mechanical atomization into the atmosphere, except at very low temperatures. At such temperatures, the small amount of moisture normally present in the atmosphere, requires that FS be thermally generated with the addition of steam to be effective. FS can be used as a fill for artillery and mortar shells and bombs and can be effectively dispersed from low performance aircraft spray tanks. FS is both corrosive and toxic in the presence of moisture, which imposes limitations on its storage, handling, and use. 

During the manufacture of glass, considerable dust, with particles averaging about 300 /xm in size, will be emitted. Some dusts may also be emitted from the handling of the raw materials involved. Control of this dust to prevent a nuisance problem outside the plant is a necessity. When glass is blown or formed into the finished product, smoke and gases can be released from the contact of the molten glass with lubricated molds. These emissions are quite dense but of a relatively short duration. 

Demand-controlled ventilation (DCV) is one approach to reduce energy consumption due to ventilation, that is gaining popularity in both industrial and nonindustrial applications. It is used in cases where ventilation requirements vary with time, regularly or irregularly. The control is based on a specified level of indoor air quality by means of continuous measurement of the parameters, that are expected to primarily determine the lAQ, such as the concentration of the main contaminant liberated from the production process. The principle is thus similar to the one in some better-known nonindustrial applications, e.g., CO2 levels in rooms with dense human occupancy (theaters, classrooms, etc.) or nicotine concentration in smoking rooms. See also Section 9.6. 

Smoke pellets are produced in a range of sizes and are commonly used tor the resting of household flues and chimneys. The pellet is ignited and will burn for about 10 seconds producing a dense white smoke. Because this is a combustion process there are obvious restrictions on its use (nonflammable atmo spheres, nonflammable surfaces, etc.). In addition the smoke is buoyant because of the heat generated. The smoke can also be an irritant and/or toxic. The production of smoke cannot be controlled, but pellets are inexpensive, easy to use, and readily available, and the smoke is produced in sufficient quantities to make them useful in the evaluation, for example, of fume cupboards and Ixroths. 

This is a clear liquid that vaporizes and, on contact with damp air, combines with w ater to produce a dense acid mist. Titanium tetrachloride can be painted on to surfaces, such as fume cupboard sills, from which it will evaporate over a period of several seconds showing the airflow patterns close to the surface. (Airflow patterns close to a surface could also be visualized by fastening short filaments of wool or cotton to the surface). Titanium tetrachloride can also be used, when soaked onto a cotton swab, in a similar way to a smoke tube. It is a simple and inexpensive method but the production of smoke, which is toxic and corrosive, is uncontrollable. 

Qualm, m. dense smoke, vapor, qualmen, emit dense smoke or vapor. 

When Explosive D is ignited in an unconfined state, it burns slowly, emitting dense black smoke without detonation. When confined and heated to its ignition temp, it will expld. When detonated completely, it emits a dense cloud of black smoke with a sooty deposit and an odor of ammonia. 

Screening smokes are generally white because black smokes are rarely sufficiently dense. Signal smokes, on the other hand, are colored so as to assure contrast and be distinct in the presence of clouds and ordinary smoke... 

False. When someone smokes tobacco, the air becomes contaminated with tobacco smoke over a wide area. This can be particularly dense when several people smoke in the same room. This smoke contains high levels of toxic chemicals and can eventually lead to all of the diseases associated with smoking, even in non-smokers who inhale it. 

Aluminium, Zinc oxide Katz, S. et al., Chem. Abs., 1981, 94, 33106 The mixture is binned militarily to produce dense smoke. 

This apparent contradiction is best explained by the ensemble behavior of dense mainstream smoke, described by Fuchs (1964). When undiluted mainstream tobacco smoke is passed horizontally into a chamber, the dense smoke column settles as an ensemble, with a gravitational settlement rate equivalent to that for individual particles of 47 /mi diameter. Such behavior can explain the remarkable retention of undiluted smoke (Hinds et al., 1983) as well as the highly nonuniform pattern of deposition for inhaled smoke tars observed by Ermala and Holsti (1955). The heaviest tar deposits occur where the dense smoke column strikes directly on projecting surfaces of the pharynx and the larynx, and at the tracheal and bronchial bifurcations (Er-... 

Red Phosphorus smoke mix production. Evaluation of the Sprout Waldron 35 cubic foot Jet Airmix unit for production of Red Phosphorus (RP) M8E1 Smoke Mixtures was conducted (12). Results indicated the mix was stabile and not easily initiated by heat, but sensitive to friction and snark stimuli. The burning time was slow with dense smoke emission. 

Commercial liquefied natural gas (NGL) is composed of at least 99% methane that has been cooled to approximately -160 °C (-256 °F), at atmospheric pressure. At this temperature is occupies only 1/600 of its original volume. LNG is less than half as dense as water, is colorless, odorless, non-toxic and sulfur free. It is vaporized as needed for use as a high quality fuel. In atmospheric burning no smoke production normally occurs. 

PS Sensitivity to UV, low temperatures, impact (apart from butadiene-modified grades), solvents, heat readily flammable with dripping and dense black smoke sometimes difficult machining. 

Titanium (IV) tetrachloride (TiCy produces a dense white smoke-like vapor when exposed to moist air. It is used as smoke screens and for skywriting, as well in theatrical productions where fog or smoke is required for the scene. 

Silicon tetrachloride (SiCy, produced when both silicon and chlorine are combined at high temperatures, is used by the military to produce smoke screens. When released in air, it reacts with the moisture in the atmosphere to produce dense clouds of water vapor. 

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