D variometer: NULL
d'Alembert's principle: The principle that the resultant of the external forces and the kinetic reaction acting on a body equals zero.
d'Arsonval galvanometer: A galvanometer in which a light coil of wire, suspended from thin copper or gold ribbons, rotates in the field of a permanent magnet when current is carried to it through the ribbons, the position of the coil is indicated by a mirror carried on it, which
dado head: A machine consisting of two circular saws with one or more chippers in between, used for cutting flat-bottomed grooves in wood.
dado joint: A joint made by fitting the full thickness of the edge or the end of one board into a corresponding groove in another board. Also known as housed joint.
dado plane: A narrow plane for cutting flat grooves in woodwork.
Dahlin's algorithm: A digital control algorithm in which the requirement of minimum response time used in the deadbeat algorithm is relaxed to reduce ringing in the system response.
Dalton's temperature scale: A scale for measuring temperature such that the absolute temperature T is given in terms of the temperature on the Dalton scale > by T = 273.15(373.15/273.15)>/100.
Dall tube: Fluid-flow measurement device, similar to a venturi tube, inserted as a section of a fluid-carrying pipe, flow rate is measured by pressure drop across a restricted throat.
damage tolerance: The ability of a structure to maintain its load-carrying capability after exposure to a sudden increase in load.
damaging stress: The minimum unit stress for a given material and use that will cause damage to the member and make it unfit for its expected length of service.
damp: To reduce the fire in a boiler or a furnace by putting a layer of damp coals or ashes on the fire bed.
damp course: A layer of impervious material placed horizontally in a wall to keep out water.
dampener: A device for damping spring oscillations after abrupt removal or application of a load.
damper loss: The reduction in rate of flow or of pressure of gas across a damper.