时间：2011-03-11 23:11来源：蓝天飞行翻译 作者：admin 点击：次
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BSFC is expressed in pounds of fuel burned per hour for each brake horsepower the engine is developing. BTC. See before top center. Btu (British thermal unit). A unit of heat measurement. The amount of heat energy needed to raise the temperature of 1 pound of pure water from 60° to 61°F. bubble memory (computer memory). A method of digital data storage in which individual bits (0s and 1s) are stored in the form of extremely small localized magnetic fields in a thin film of magnetic crystalline material. Bits of stored data can be moved about by the use of an external magnetic field. bubble octant (navigation instrument). A type of celestial navigation instrument. A bubble level in the octant provides an artificial horizon which allows the navigator to find the angle between a line tangent to the earth’s surface (the horizon) and a line to the stars being used for navigation. bubble. A small volume of gas entrapped in a liquid. bucket wheel. A turbine wheel in a turbosupercharger or in a gas turbine engine. bucket. Colloquial, or informal, term for a turbine blade. bucking (rivet bucking). The process in which a shop head is formed on a solid aircraft rivet. The rivet is inserted into holes drilled through the metal sheets being joined. The manufactured head of the rivet is hammered with a pneumatic hammer through a rivet set that fits the shape of the head. A hardened-steel bucking bar is held against the shank of the rivet, and the hammering causes the end of the shank to expand and become shorter, forming the shop head that clamps the metal pieces together. bucking bar (sheet metalworking tool). A heavy steel block or bar with smooth, hardened surfaces, or faces. A bucking bar is held flat against the end of the shank of a solid rivet when the head is driven with a rivet gun. Driving the rivet flattens the end of the shank against the bucking bar and forms the bucked, or shop, head. bucking voltage. A voltage used to oppose another voltage. When one voltage is bucked by another which has the same value but opposite polarity, the result is zero voltage. buckle (sheet metal damage). A wrinkle or kink in the surface of a sheet metal aircraft structure caused by an excessive bending or compressive load on the structure. buffer (digital electronic component). A digital electronic component that has one input and one output, with the output having the same condition as the input. A buffer is used to isolate an input or strengthen a signal. buffer amplifier (electronic circuit). An amplifier used to isolate one circuit from another circuit. Buffer amplifiers prevent one circuit from loading the other and causing it to operate improperly. |
