A line source is a source of air, noise, water contamination or electromagnetic radiation that emanates from a linear (one-dimensional) geometry. The most prominent linear sources are roadway air pollution, aircraft air emissions, roadway noise, certain types of water pollution sources that emanate over a range of river extent rather than from a discrete point, elongated light tubes, certain dose models in medical physics and electromagnetic antennas. While point sources of pollution were studied since the late nineteenth century, linear sources did not receive much attention from scientists until the late 1960s, when environmental regulations for highways and airports began to emerge. At the same time, computers with the processing power to accommodate the data processing needs of the computer models required to tackle these one-dimensional sources became more available.
In addition, this era of the 1960s saw the first emergence of environmental scientists who spanned the disciplines required to accomplish these studies. For example, meteorologists, chemists, and computer scientists in the air pollution field were required to build complex models to address roadway air dispersion modeling. Prior to the 1960s, these specialities tended to work within their own disciplines, but with the advent of NEPA, the Clean Air Act, the Noise Control Act in the USA, and other seminal legislation, the era of multidisciplinary environmental science had begun.
For electromagnetic linear sources, the principal early advances in computer modeling arose in the Soviet Union and USA when the end of World War II and the Cold War were fought partially by progress in electronic warfare, including the technologies of active antenna arrays.
Other articles related to "line, source, line source, sources":
... Pure line array theory is based on pure geometry and the thought experiment of the "free field" where sound is free to propagate free of environmental factors such as room reflections ... In the free field, sound which has its origin at a point (a point source) will be propagated equally in all directions as a sphere ... for every doubling of distance from the point source ...
... A line array is a loudspeaker system that is made up of a number of loudspeaker elements coupled together in a line segment to create a near-line source of sound ... Line arrays can be oriented in any direction, but their primary use in public address is in vertical arrays which provide a very narrow vertical output pattern useful for focusing ... A vertical line array displays a normally-wide horizontal pattern useful for supplying sound to the majority of a concert audience ...
... behind this method is the infinite line source with constant power per unit length ... in is the exponential integral, a transcendent mathematical function is the radial distance to the line source is the thermal diffusivity, in is the amount of time that has passed since heating has started ...
... In the study of illumination, a variety of sources are linear in nature, most commonly the fluorescent tube, During the process of interior lighting ... scientists involved in light transmission calculations employ computer models that recognize linear sources when fluorescent fixtures are used ... setting there may be hundreds of finite length light sources that comprise the light output in an office environment ...
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