tion of information. Note: There are five types of con verters: analog – digital – converter, digital – analog – converter, code – converter, parallel – serial – conver ter, serial – parallel – converter. 2. A type of refining furnace where impurities are oxidized and removed by blowing air or oxygen through the molten metal.
convex programming In operations research, a par ticular case of nonlinear programming in which the function to be maximized or minimized and the cons traints are appropriately convex or concave functions of the controllable variables.
conveyance The carrying capacity of a channel ex- pressed in terms of the discharge and the bed slope. See further British Standard 3680: Part 1:1983.
conveyor-type furnace A type of continuous heat- treating furnace constructed similarly to roller-hearth furnaces except that belt conveyors are used to carry the material through the furnace.
convolution integral A mathematical integral ope- ration which is used to describe the time response of a linear element to an input function in terms of the weighting function of the element.
cooking Pertaining to pulp and paper manufacturing, treatment of fiber raw material with heat at a mini- mum temperature of 100°C and with water, normally with the addition of chemicals.
cooler (heat exchanger) A device used to transfer heat between two fluids without direct contact bet- ween them.
Coolidge tube An X-ray tube in which the electrons are produced by a hot cathode.
cooling Pertaining to heat treatment, departure of heat acompanied by a reduction in temperature; com pare quenching. When neccessary, a distinction can be made between free departure of heat into the air, un-
cooling fan 98 corrective maintenance
controlled cooling, and restrained departure as in an oven, slow cooling.
cooling fan (fluid power systems) Device which mechanically creates a flow of air over a hot surface, usually used with a radiator in order to increase the rate of heat exchange.
cooling rate Pertaining to heat treatment, quotient of temperature reduction and time in cooling; See criti cal cooling rate.
cooling tower A large louvered structure (usually made of wood) over which water flows to cool and ae rate it. Although most cooling towers are square or rectangular in shape, some are cylindrical, open at the bottom and top, which produces strong air currents th rough the center of the structure for more rapid coo- ling.
cooling water Water which is used to absorb and re- move heat.
coordinate digitizer A device that transcribes graphic information in terms of a coordinate system for subsequent processing.
coordinate dimension word (numerical con trol) A word defining an absolute dimension.
coordinate geometry A language useful for solving coordinate geometry problems in civil engineering.
copper-clad steel Steel with a coating of copper welded to it, as distinguished from copper-plated or copper-sheated material.
copper corrosion (fluid power systems) Indica ted by the change of appearance of an electrolytic copper plate immersed in the fluid under stated condi tions.
copper versus copper-nickel Material indentifica tion for thermocouple type T. Normally suitable for relatively low temperature measurement, especially sub-zero temperatures. See ISA publication ANSI-M 96.1-1982.
coprocessor A device added to a CPU that performs special functions more efficiently than the CPU alone.
copy To read data from a source data medium, leaving the source data unchanged, and to write the same data on a destination data medium that may differ from that of the source. Example: To copy a file from a magnetic tape onto a magnetic disk.
Corbino effect A special case of the Hall effect that occurs when a disc carrying a radial current is placed perpendicularly into a magnetic field.
cord One or a group of flexible insulated conductors covered by a flexible insulation and equipped with ter minals.
core (optical communication) The central region of an optical fiber through which most of the optical power is transmitted.
core array A rectangular grid of cores containing a given number of words each of a given number of bits making up the rectangular array.
core iron A grade of soft steel suitable for making co res used in electromagnetic devices.
core loss Also called iron loss. Loss of energy in a magnetic core as the result of eddy currents, which circulate through the core and dissipate energy in the form of heat.
core memory A storage device in which binary data is represented by the direction of magnetization in each unit of an array of magnetic material, usually in the shape of toroidal rings, but also forms such as wraps on bobbins.
core plane A horizontal network of magnetic cores that contains a core common to each storage position.
core resident A term pertaining to programs or data permanently stored in core memory for fast access.
core storage Same as core memory. See core memo ry.
core-type induction heater A device in which an object is heated by induction.
core wrap Insulation placed over a core before the addition of windings.
Coriolis-type mass flowmeter An instrument for measuring mass flowrate by determining the torque from radial acceleration of the fluid.
Corliss valve A type of valve used to admit steam to, or exhaust it from, a reciprocating engine cylinder.
corner (pressure) tappings Wall pressure tappings drilled on either side of an orifice plate or nozzle with the spacing between the axes of the pressure tappings and the respective faces of the plate or nozzle equal to half the diameter of the tappings themselves, so that the tapping holes break through the conduit wall flush with the faces of the plate or nozzle. Pertains to mea surement of fluid flow in closed conduits. See figure in ISO publication 4006-1977 or BS 5875:1980.
corner frequency In the asymptotic form of Bode diagram, that frequency indicated by the junction of two confluent straight lines asymtotic to the logarith mic gain curve.
corona discharge A phenomena that occurs when an electric field is sufficiently strong to ionize the gas between electrodes and cause conduction.
coroutines Two or more modules that can call each other, but that are not in a superior to subordinate rela tionship.
corpus A body or mass of data, most often in unredu ced form and as selected for study or analysis.
corrected result The result of a measurement obtai ned after having made corrections to the uncorrected result in order to take account of assumed systematic errors.
correcting element The final control element in a process control system.
correcting range, manipulated range Interval defined by the two extreme values that the manipula ted variable can assume.
correction The value which must be added algebrai cally to the uncorrected result of a measurement to obtain the corrected result. This value is minus the known part of the systematic error. Note: The uncor rected result of a measurement is often referred to as “indicated value” and the corrected result as “measu red value”. The use of both terms is not recommen ded.
correction factor The numerical factor by which the uncorrected result of a measurement is multiplied to compensate for an assumed systematic error. Note: Since the systematic error cannot be known exactly, the correction factor is subject to uncertainty.
correction for oblique flow The correction to be made to an observed velocity when the direction of flow at the place of measurement is not at right angles to the measuring section. Pertains to liquid flow mea surement in open channels.
correction program See correction routine.
correction routine A routine used in or after a com puter failure, malfunction, or program or operator er ror. It reconstitutes the routine executed before the er ror occured and from the closest rerun point.
correction time See settling time.
corrective action The change produced in a control- led variable in response to a control signal.
corrective maintenance The maintenance carried out after fault recognition and intended to restore on item to a state in which it can perform a required func-
corrective maintenance time 99 crevice corrosion
tion. Synonymous with emergency maintenance. Contrast with preventive maintenance.
corrective maintenance time That part of the maintenance time, during which corrective mainte nance is performed on an item, including technical de- lays and logistic delays inherent in corrective mainte nance.
corrective network Also called shaping network. An electric network designed to be inserted into a cir cuit to improve its transmission or impedance proper- ties, or both.
correctness (software) 1. The extent to which soft-
ware is free from design defects and from coding de fects, that is, fault free. 2. The extent to which softwa re meets its specified requirements. 3. The extent to which software meets user expectations.
correed A glass-enclosed miniature reed switch.