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A chemical substance that, when added to a liquid such as water, reduces the freezing point of the mixture. Antifreezes are used in a wide variety of applications, the most common being automotive cooling systems. Antifreeze liquids are also used in…

A machine element that permits free motion between moving and fixed parts. Antifriction bearings are essential to mechanized equipment; they hold or guide moving machine parts and minimize friction and wear. Friction wastefully consumes energy, and…

The condition for which the impedance of a given electric, acoustic, or dynamic system is very high, approaching infinity. In an electric circuit consisting of a capacitor and a coil in parallel, antiresonance occurs when the alternating-current…

A type of electrical conduction in gases characterized by high current density and low potential drop. The electric arc was discovered by Humphry Davy in 1808, when he connected a piece of carbon to each side of an electric battery, touched the two…

The heating of matter by an electric arc. The matter may be solid, liquid, or gaseous. When the heating is direct, the material to be heated is one electrode; for indirect heating, the heat is transferred from the arc by conduction, convection, or…

A type of electric-discharge lamp in which an electric current flows between electrodes through a gas or a vapor. In most arc lamps the light results from the luminescence of the gas; however, in the carbon arc lamp a major portion of the light is…

A welding process utilizing the concentrated heat of an electric arc to join metal by the fusion of the parent metal and any filler metal added to the joint, usually in the form of a consumable electrode or, for nonconsumable electrode processes, as…

A structural member that spans horizontally between supports that develop inwardly directed horizontal reactions when the member is subjected to a vertical load. The member axis is usually curved and usually lies in a vertical plane. Arches are used…

A bridge with vertically curved compression-dominant members spanning an opening to support moving loads; it is the oldest bridge type. An arch bridge over a deep valley is beautiful and has no competitor as far as aesthetics are concerned.Arch…

The science of sound as it pertains to buildings. There are three major branches of architectural acoustics. (1) Room acoustics involves the design of the interior of buildings to project reflected and diffused sound at appropriate levels and time…

The conversion of any nonaromatic hydrocarbon structures, especially those found in petroleum, to aromatic hydrocarbons. There are numerous routes and means to accomplish this transformation, the simplest and most important of which are direct…

Varieties of naturally occurring bitumen. Asphalt is also produced as a petroleum by-product. Both substances are black and largely soluble in carbon disulfide. Asphalts are of variable consistency, ranging from a highly viscous fluid to a solid,…

Machines that take discrete components as come into an assembly department and bring them together so as to produce a configuration of some practical value. Such machines differ from packaging machinery in two ways: in assembly machinery, components…

The process whereby a bulk liquid is transformed into a multiplicity of small drops. This transformation, often called primary atomization, proceeds through the formation of disturbances on the surface of the bulk liquid, followed by their…

The exponential decrease with distance in the amplitude of an electrical signal traveling along a very long uniform transmission line, due to conductor and dielectric losses. If the peak voltage at the sending end of the transmission line is denoted…