Chemical agents surfaces

Decontamination. If contaminated equipment or material does not have to be used immediately, natural aeration is an effective decontaminant procedure, as most chemical agents, including the bHster and V-agents, are volatile to a certain degree. Wind accelerates their evaporation and hastens their dissipation. Rain and dew may also cause sufficient hydrolysis of some agents. Sunlight increases the surface temperatures of military equipment and thus accelerates agent evaporation. 

Chemical cleaning implies the removal of material from the surface of the specimen by dissolution in an appropriate chemical agent. Solvents such as acetone, carbon tetrachloride, and alcohol are used to remove oil, grease, or resin and are usually apphed prior to other methods of cleaning. Various chemicals are chosen for appheation to specific materials some of these treatments in general use are outlined in the NACE standard. 

Aluminium is a very reactive metal with a high affinity for oxygen. The metal is nevertheless highly resistant to most atmospheres and to a great variety of chemical agents. This resistance is due to the inert and protective character of the aluminium oxide film which forms on the metal surface (Section 1.5). In most environments, therefore, the rate of corrosion of aluminium decreases rapidly with time. In only a few cases, e.g. in caustic soda, does the corrosion rate approximate to the linear. A corrosion rate increasing with time is rarely encountered with aluminium, except in aqueous solutions at high temperatures and pressures. 

The freshly exposed surface is treated with a chemical agent, or dopant, to modify its electrical properties (e.g., to create transistors). 

Alak AM, Vo-Dinh T. 1987. Surface-enhanced raman spectrometry of organophosphorus chemical agents. Anal Chem 59 2149-2153. 

Denaturation is a change in which the natural protein becomes insoluble in solutions in which it was previously soluble. It is brought about by physical means such as heat, pressure, and surface force, or by chemical means, although very few chemical agents are used in this connection in the food field. Gel-type solutions are usually beaten before they become too thick or firmly set. As air is incorporated, the volume increases and the firmness of the gel stabilizer sets the foam. 

Sensors that operate on the basis of interactive chemical surfaces are chosen for discussion here because they are likely candidates for the detection of chemical agents. However, many other sensor types are possible. 

In addition to the use of antifouling chemical agents to mitigate the effect of fouling on the tube-side, twisted tubes can be used rather than plain tubes. These have surface irregularities. Plain tubes can also be fitted on the inside with tube inserts. Twisted tubes and tube inserts promote additional turbulence and pressure drop and reduce the surface temperature of the tube to mitigate fouling. Tube inserts will be dealt with in more detail later. 

Dry chemical agents currently used are a mixture of powders, primarily sodium bicarbonate (ordinary), potassium bicarbonate (Purple K), monoammmonium phosphate (multipurpose). When applied to a fire they cause extinguishment by smothering the fire process. They will not provide securement of a flammable liquid spill or pool fire and it can re-flash after it is initially suppressed if an ignition source is present (i.e., a hot surface). Dry chemical is still very effective for extinguishment of three dimensional flammable liquid or gas fires. It is nonconductive and therefore can be used on live electrical equipment. 

Joint Chemical Agent Detector (JCAD) This detector will employ surface acoustic wave technology to detect nerve and blister agents. It will also allow detection of new forms of nerve agents. 

Acoustic wave sensors are also used to detect nerve and blister agents. The surface acoustic wave chemical agent detector (SAW Mini-CAD) is a commercially available, pocket-sized instrument that can monitor for trace levels of toxic vapors of sulfur-based mustard agents (e.g., distilled mustard) and G nerve agents (e.g., tabun, sarin, soman) with a high degree of specificity. Colorimetric tubes are the... 

The first chemical agents used in composite fabrication were amino acids [179] for synthesizing Nylon 6. Other agents are also used in the synthesis of nanomaterials, however, the most popular are alkylammonium ions due to their ability to exchange ions located between the layers of the clay. In addition, silanes have been widely used due to their ability to react with the hydroxyl groups on the surface and edges of the clay layers. 

The physical transport of oil droplets into the water column, called dispersion, is often a result of water surface turbulence but may also result from the application of chemical agents (dispersants). These droplets may remain in the water column or coalesce with other droplets and gain enough buoyancy to resurface. Dispersed oil tends to biodegrade and dissolve more rapidly than floating slicks because of high surface area relative to volume. Most of this process occurs from about half an hour to half a day after the spill. 

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