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Revision as of 19:43, 10 March 2009 by imported>Todd Coles (updated article/draft of the week)
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Article of the Week [ about ]

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Coal-fired power plant in Voerde, Germany

A conventional coal-fired power plant produces electricity by burning coal in a steam generator that heats water to produce high pressure and high temperature steam. The steam flows through a series of steam turbines which spin an electrical generator to produce electricity. The exhaust steam from the turbines is cooled, condensed back into water, and returned to the steam generator to start the process over.

Conventional coal-fired power plants are highly complex and custom designed on a large scale for continuous operation 24 hours per day and 365 days per year. Such plants provide most of the electrical energy used in many countries.

Most plants built in the 1980s and early 1990s have a power of around 500 MW (500•106 watt), while many of the modern plants have a power of around 1000 MW. Also the efficiencies (ratio of electrical energy produced to energy released by the coal burned) of conventional coal-fired plants increased from under 35% to close to 45%. Because of the second law of thermodynamics there is a fixed physical limit on the efficiency. By Carnot's law the limit is proportional to the temperature difference of the steam and the cooling water, with the consequence that the efficiency of a plant cannot surpass 50% by much.[more...]

New Draft of the Week [ about ]

The Jass–Belote card games are a family of trick-taking card games in which the Jack ("jass") and Nine of the trump suit are the highest-ranking trumps, and the Tens and Aces of all suits are the next most valuable cards. Games in this family are typically played by 2 or 4 players with the 32 French-suited cards of a piquet pack.

Variants of the basic 2-handed game – known under various names including Klaberjas, Clob and Bela – are played worldwide, especially in Jewish communities. 4-handed Belote with its numerous variants is the French national card game but has spread as far away as Cyprus and Saudi-Arabia. Other notable members of the family include the Swiss and Dutch national card games (Swiss Jass and Dutch Klaverjas). Twenty-Nine, a popular game in South Asia, is a descendent of these games sharing many of their characteristics. [more...]