CONCAVE– Hollowed or rounded inward like the inside of a bowl. CONTAMINANTS– Substances that contaminant other substances. CONVEX– Curving outward like the surface of a sphere. COUNTERSINK– To set the head of a screw at or below the surface. CRES– Comosion-resistant steel. CRYSTALLINE– Composed of crystals. CYLINDRICAL– Relating to or having the form or properties of a cylinder. DEAERATE– To remove air or gas from. DECONTAMINATE– To rid of contamination. DESICCANT– A drying agent. DETERIORATION– The act or process of becoming impaired in quality, functioning, or conditioning. DYNAMIC SEAL– Seal between two parts with relative motion. ELECTROHYDRAULIC– A combination of electric and hydraulic mechanisms. ELONGATED– Stretched out. EMULSION– A suspension of small globules of one liquid in a second liquid with which the first will not mix, such as milk fats in milk. EPOXY– A compound in which an oxygen atom is joined to each of two attached atoms, usually carbon. Designation of various thermosetting resins, containing epoxy groups, that are blended with other chemicals to form strong, hard, chemically resistant substances, such as adhesives, paints, etc. ERRATIC– Deviating from the normal, conventional, or customary course. EUTECTIC– Mixture or alloy with a melting point lower than that of any other combination of the same components. EXTRUDED– To push or force out, expel. To force (metal, plastic, etc.) through a die or very small holes to give it a certain shape. FERROUS– Substances containing iron. FIBER– A single strand of material that is rolled or formed in one direction, and used as a principal constituent in composite material because of its high axial strength and modulus. FUSIBLE– Liquified by heat, easily melted. GALLING– Chafing. GPM– Gallons per minute. HALOGEN– Any of the five elements fluorine, chlorine, iodine. nonmetallic chemical bromine, astatine, and HELICAL– Something spiral in shape. HONEYCOMB– A strong, lightweight, cellular struc- tural material. HP– Horsepower. HYDRAULICALLY– Operated by the resistance offered or by the pressure transmitted when a quantity of liquid, such water or oil, is forced through a small orifice or tube. HYDROCARBON– An organic compound containing only carbon and hydrogen and often occurring in petroleum, natural gas, coal and bitumens. HYDROCHLORIC ACID– A strong, highly corrosive acid that is a water solution of the gas hydrogen chloride, and is widely used in the processing of ore and for cleaning metals. HYDROLYZE– To decompose a compound by split- ting it into other compounds by taking up water. IMBEDDED– To make something an integral part of. IMPREGNATED– To furnish one substance with some actuating or modifying substance that is infused or introduced. An example is the nonwoven, non- metallic, abrasive mats that are used for the removal of corrosion products and paint scuffing prior to painting. These abrasive mats are, in effect, nylon webbing, impregnated with aluminum oxide. INERT– Lacking a usual or anticipated chemical or biological action. INHIBITOR– An agent that slows or interferes with a chemical reaction. INTEGRAL FUEL CELL– A structural configuration in which a component of the aircraft serves as a fuel container. KEVLAR®– tough, light, aramid synthetic fiber used in making bulletproof vests, boat hulls, airplane parts, etc. AI-2