Annealing (metallurgy) brass can be cooled slowly in air, or quickly by quenching in water, unlike ferrous metals, such as steel, which must be cooled slowly to anneal. In this fashion, the metal is softened and prepared for further work—such as shaping, stamping, or forming. Annealing occurs by the diffusion of atoms within a solid material, so that the material progresses towards its equilibrium state. Heat increases the rate of diffusion by providing the energy needed to break bonds. The movement of atoms has the effect of redistributing and eradicating the dislocations in metals and (to a lesser extent) in ceramics. This
Building insulation cavities like the attic. This is beneficial in an actively cooled or heated building, but can be a liability in a passively cooled building; adequate provisions for cooling by ventilation or radiation are needed. Fibrous materials are made by tiny diameter fibers which evenly distribute the airspace. The commonly used materials are silica, glass, rock wool, and slag wool. Glass fiber and mineral wool are two insulation materials that are most widely used in this type. Cellular insulation is composed of small cells which are separated from each other. The commonly cellular materials are glass and foamed plastic like polystyrene,