useful efficiency
81gas-turbine engine — Introduction any internal combustion engine employing a gas as the working fluid used to turn a turbine. The term also is conventionally used to describe a complete internal combustion engine consisting of at least a compressor, a… …
82Orthogonal frequency-division multiplexing — Passband modulation v · d · e Analog modulation AM · …
83Economic growth — GDP real growth rates, 1990–1998 and 1990–2006, in selected countries …
84Cogeneration — For other uses, see CHP (disambiguation). Sustainable energy Renewable energy …
85Mathematics and Physical Sciences — ▪ 2003 Introduction Mathematics Mathematics in 2002 was marked by two discoveries in number theory. The first may have practical implications; the second satisfied a 150 year old curiosity. Computer scientist Manindra Agrawal of the… …
86ancient Greek civilization — ▪ historical region, Eurasia Introduction the period following Mycenaean civilization, which ended in about 1200 BC, to the death of Alexander the Great, in 323 BC. It was a period of political, philosophical, artistic, and scientific… …
87Metamaterial antenna — This Z antenna tested at the National Institute of Standards and Technology is smaller than a standard antenna with comparable properties. Its high efficiency is derived from the Z element inside the square that acts as a metamaterial, greatly… …
88Engine — This article is about a machine to convert energy into useful mechanical motion. For other uses of engine, see Engine (disambiguation). For other uses of motor, see Motor (disambiguation). A V6 internal combustion engine from a Mercedes car An… …
89computer — computerlike, adj. /keuhm pyooh teuhr/, n. 1. Also called processor. an electronic device designed to accept data, perform prescribed mathematical and logical operations at high speed, and display the results of these operations. Cf. analog… …
90operations research — the analysis, usually involving mathematical treatment, of a process, problem, or operation to determine its purpose and effectiveness and to gain maximum efficiency. [1940 45, Amer.] * * * Application of scientific methods to management and… …
