Animal resistant coating

Humidity sensors may be animal or plastic skins varying in length with changes in rh or lithium chloride coating changing in electrical resistance. The former is prone to lose calibration. Other comments above apply equally to rh control. 

Waxes are biosynthesized by plants (e.g., leaf cuticular coatings) and insects (e.g., beeswax). Their chemical constituents vary with plant or animal type, but are mainly esters made from long-chain alcohols (C22-C34) and fatty acids with even carbon numbers dominant (Fig. 7.11). They may also contain alkanes, secondary alcohols, and ketones. The majority of wax components are fully saturated. The ester in waxes is more resistant to hydrolysis than the ester in triacylglycerols, which makes waxes less vulnerable to degradation, and therefore more likely to survive archaeologically. 

Another use of urea is for resins, which are used in numerous applications including plastics, adhesives, moldings, laminates, plywood, particleboard, textiles, and coatings. Resins are organic liquid substances exuded from plants that harden on exposure to air. The term now includes numerous synthetically produced resins. Urea resins are thermosetting, which means they harden when heated, often with the aid of a catalyst. The polymerization of urea and formaldehyde produces urea-formaldehyde resins, which is the second most abundant use of urea. Urea is dehydrated to melamine, which, when combined with formaldehyde, produces melamine-formaldehyde resins (Figure 96.2). Melamine resins tend to be harder and more heat-resistant than urea-formaldehyde resins. Melamine received widespread attention as the primary pet food and animal feed contaminant causing numerous cat and dog deaths in early... 

Some shelled gastropods do produce chemical defenses, although this is far less common. One South African limpet, Siphonaria capensis, occurs at very high densities on rocky shores, apparently protected from predators by chemical feeding deterrents. These animals are rarely consumed relative to Patella granularis (a similar limpet that lacks defensive chemistry) and exude a repellent mucus onto the surface of their shell when attacked. Nonpolar extracts from Siphonaria confer resistance from predation to Patella when they are coated on its shell.20 Because the metabolites responsible for the chemical defense have not been fully isolated and characterized, it is still unclear whether the compounds that confer resistance to predation in Siphonaria are diet derived or synthesized de novo. 

Vicunas are smaller than llamas, and adults weigh only about 100 pounds. Hairs from this animal are the finest or thinnest known, about 1/2000 inches in diameter. Like other camel relatives, the vicuna has a layered coat. The innermost hairs are extremely soft, elastic, and have a strongly cohesive outer surface. This last property makes these fibers resistant to dyes, stains, and water. As these animals are small, and their hair so fine, it takes fleece from about forty vicuna to make one coat. 

Iron poisoning often is not recognized as a potentially serious problem by parents or victims until symptoms develop, and thus valuable time to institute treatment is lost. Parents should be made aware of the potential risks and asked to observe basic poison prevention measures. Many chewable vitamins with iron are shaped like animal or cartoon characters that can be attractive to children and can lead to poisoning. Some hard-coated iron tablets resemble candy-coated chocolates and are confused easily by children. Based on these considerations and the frequency of this poisoning, iron tablets are packaged in child-resistant containers. 

One very interesting application for polyphenylene sulfide is in coating cookware for nonstick use (10). Excellent, scratch-resistant, nonstick coatings are obtained when a formulation containing 10 to 20% polytetrafluoroethylene is used. Ryton PPS coatings are very insoluble and nontoxic, animal feeding studies indicate. 

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