Fastener

For dissimilar metal connections (aluminum to steel) in a marine environment, stainless steel fasteners installed with heads on the weather side are preferred. Fasteners should be dipped in zinc chromate primer or sealing compound. If stainless steel cannot be used, the exposed ends of fasteners should be encapsulated. 

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Fig. 32). Using a fine pipette insert about i cm. length of the liquid into the bottom of the tube. Now place in the tube A a fine inverted melting-point tube B of about i mm. diameter, sealed at the upper end. Fasten the capillary tube to the ther- Fio. 32. mometer by means of a rubber band and place in a melting-point apparatus. Heat slowly until a stream of bubbles rises from the bottom... 

A convenient form of apparatus, particularly for large classes, is shown in Fig. 84 it is identical with that used for the determination of the equivalent weight of metals by hydrogen evolution. A and H are glass tubes connected together by the rubber tubing J and securely fastened to the board B. The tube A is... 

Clothes. Laboratories should be equipped with a sufficient number of fireproof blankets, so that a blanket is available at any point of the laboratory at a few seconds notice. Each blanket should be kept in a clearly labelled box, the lid of which is closed by its own weight and not by any mechanical fastening, which might delay removal of the blanket. The box itself should be kept in some open and unencumbered position in the laboratory. 

Polymers are characteri2ed as thermosetting and thermoplastic with respect to the methods by which they are joined. Thermosetting polymers are permanently hard and do not soften upon the apphcation of heat they are joined by mechanical fasteners and adhesives. Several methods have been devised to join thermoplastic polymers, as weU as thermoplastic composite materials, which soften upon heating. 

Wood is one of the oldest constmction materials in human use and continues to be an extremely valuable material to this day. Wood is lightweight, strong, stable, easily worked and fastened, a good insulator, warm to the touch, and pleasing in appearance, among many other attributes. 

Sound-Absorptive Blankets. Sound-absorptive blankets of fiber glass or mineral wool are not usually considered damping materials, but when fastened to sheet metal machine enclosures they can provide some useful damping in addition to sound absorption. 

Cadmium usage, illegal in most of Europe, is being discouraged elsewhere. The U.S. military has cadmium specifications for electronic, fastener, and marine equipment, which requires only cadmium. Tin is being substituted for tin—lead as a metallic etch resist during printed circuit board production. 

Emulsification involves the joining of two mutually insoluble materials, such as petroleum oil and water. The surfactant, which usually has a hydrophilic or water-soluble end and a hydrophobic or oil-soluble end, holds the oil and water together in much the same manner that a fastener holds two pieces of material. Often, the emulsion which forms is unstable, subsequently breaking up and releasing the oil from the water. Break-up is actually preferred, because the oil then floats to the surface, whereas the surfactant is free to emulsify more oil. 

A majority of the fasteners used in automobiles in the United States are coated with microcapsules loaded with an adhesive. When the fastener is installed, a fraction of the capsules in the coating mpture releasing the adhesive payload. The adhesive essentially glues the fasteners in place preventing them from becoming loose and causing rattles. The capsules are designed so that only a fraction of them break each time a fastener is taken off and put back. The on/off cycle can be repeated three or four times. 

Typical apphcations for the nickel—copper alloys are in iadustrial plumbing and valves, marine equipment, petrochemical equipment, and feedwater heat exchangers (see Piping systems). The age-hardened alloys are used as pump shafts and impellers, valves, drill parts, and fasteners (see Pumps). 

Plastic dmms are made with either integral or removable heads, depending on the need of the customer. The chemical industry is more likely to use integral or tight-head dmms, whereas the food industry is prone to use open-head dmms to which separate covers can be fastened. The choice between these two styles often is deterrnined by the requirement for cleaning the dmm interior. 

A triangular shaped wheel cover with the center cut out to provide hub access was then applied to a wheel. The cover was constructed from a heat shrinkable poly- 10 olefin ftlm. Tape was attached to the apex points of the triangle. The tape liner was removed and the three adhesive sites were fastened to the spokes. As an identical complementary cover was then applied to the opposite face of the wheel in a mirror image fashion. The 1 adhesive contact points were positioned to encapsulate the spoke on either side within the adhesive contact point. Heat was then used to shrink the covers and achieve a wrinkle-free condition. This example demonstrates that design can play a part in providing a stylish wheel cover that is capable of individualizing the bicycle to meet a wide variety of consumer tastes. 

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