Heat Transfer and the Second Law of Thermodynamics

demonstrations.wolfram.com The Wolfram Demonstrations Project contains thousands of free interactive visualizations, with new entries added daily. Two thermal reservoirs at the same temperature, T_2=T_1, can, in concept, exchange an increment of heat ? q in either direction. Since it can just as easily flow in the opposite direction, this represents what is known as a reversible process and ? q ca... Contributed by: SM Blinder
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Neon is the chemical element that has the symbol Ne and atomic number 10. Although a very common element in the universe, it is rare on Earth. A colorless, inert noble gas under standard conditions, neon gives a distinct reddish-orange glow when used in discharge tubes and neon lamps. It is commercially extracted from air, in which it is found in trace amounts. Neon was discovered in 1898 by Scottish chemist Sir William Ramsay (18521916) and English chemist Morris W. Travers (18721961) in London, England. Neon was discovered when Ramsay chilled a sample of the atmosphere until it became a liquid, then warmed the liquid and captured the gases as they boiled off. The three gases that boiled off were krypton, xenon, and neon. In December of 1910, French engineer Georges Claude made a lamp from an electrified tube of neon gas. On January 19, 1915, Claude began selling his tubes to US companies; the Packard car dealership in Los Angeles was one of the first to buy it. Neon is often used in signs and produces an unmistakable bright reddish-orange light. Although still referred to as "neon", all other colors are generated with the other Noble Gases or by many colors of fluorescent lighting. Neon is used in vacuum tubes, high-voltage indicators, lightning arrestors, wave meter tubes, television tubes, and helium-neon lasers. Liquefied neon is commercially used as a cryogenic refrigerant in applications not requiring the lower temperature range attainable with more extreme liquid ...
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