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=== Article of the Week <font size=1>[ [[CZ:Article of the Week|about]] ]</font> ===
=== Article of the Week <font size=1>[ [[CZ:Article of the Week|about]] ]</font> ===
{{Image|Shallow Ground-level Trickle Filters.jpg|right|200px|Large, shallow ground-level trickle filters in a municipal wastewater treatment plant}}
The '''[[Ether (physics)|ether]]''' (also spelled<ref>Generally speaking the spelling "ether" is more modern than "aether". Note, however, that two Americans, A. A. Michelson and E.W. Morley, spelled it as "ether" as early as 1887.</ref> '''aether''') was a concept in [[physics]] made obsolete in 1905 by [[Albert Einstein|Einstein]]'s theory of [[special relativity]].  
'''[[Large-scale trickle filters]]''' are wastewater treatment facilities for biochemically oxidizing biodegradable substances present in wastewaters. They consist of a fixed bed of [[Rock (geology)|rock]]s, [[gravel]], [[slag]], [[polyurethane|polyurethane foam]] or plastic media over which [[sewage]] or other [[biodegradable]] [[wastewater]] percolates downward and is contacted with a layer or film of [[Microbe|microbial]] slime covering the bed media. [[Aerobic]] conditions are maintained by air flowing through the bed.


The terms ''trickling biofilter'', ''biofilter'', ''biofilm reactor'', ''biological filter'', ''biological trickling filter'' and ''biotower'' are often used to refer to a trickle filter. These systems have also been described as an attached growth process
The idea of an ether was introduced into science by [[René Descartes|Descartes]] in [[Principles of Philosophy|Principia philosophiae]] (1644). Until that time, forces between two bodies that are not in direct contact were assumed to act through space&mdash;by [[action at a distance]]. Descartes  replaced this explanation by one based on an intermediate medium (ether) consisting of vortices that transmit forces between bodies at a distance.
, a fixed film process, [[Packed bed|packed media bed]] filters, roughing filters and percolating filters.  
 
<font size=1>[[Large-scale trickle filters|['''more...''']]]</font>
The ether concept became especially predominant in the 19th century by the work of [[Thomas Young|Young]] and [[Augustin-Jean Fresnel|Fresnel]] who revived [[Christiaan Huygens|Huygens]]' wave theory of light.  They replaced [[Newton]]'s light corpuscles by waves propagating through the ether. In order to explain [[stellar aberration]], first observed in the 1720s and then shown to be caused by the velocity of the earth relative to the velocity of Newton's light corpuscles, Young (1804) assumed ether to be in a state of absolute rest. [[James Clerk Maxwell|Maxwell]] showed in the 1860s that light waves are [[electromagnetic wave]]s  transverse (perpendicular) to the direction of the propagation  of the waves. Following Young and FresnelMaxwell assumed that electromagnetic waves are vibrations of the ether.  
<font size=1>[[Ether (physics)|['''more...''']]]</font>


=== New Draft of the Week <font size=1>[ [[CZ:New Draft of the Week|about]] ]</font> ===
=== New Draft of the Week <font size=1>[ [[CZ:New Draft of the Week|about]] ]</font> ===
'''[[Joseph Black]]''' (1728-1799), was a Scottish chemist and physicist, known for the concepts of [[latent heat]] and [[specific heat]], and for the discovery of [[carbon dioxide]]. He was a founder of [[thermochemistry]], and was the mentor of [[James Watt]]. Black was a member of the [[Poker Club]] and friend of [[David Hume]], [[Adam Smith]], [[James Hutton]] and other leading figures of the [[Scottish Enlightenment]].
In computer and network security, a '''[[Worm (computers)|worm]]''' is a form of [[malware]] that, once it activates inside a victim's computer, can replicate and propagate itself without further user activity. Worms often take up valuable memory and network bandwidth, which can cause a computer to stop responding, and can also allow attackers to gain unauthorized remote control of one or more computers.  


Joseph Black was one of fifteen children (8 sons and 5 daughters surviving). His father, John Black, was a wine merchant; his  mother, Margaret, was from Aberdeenshire. At the age of twelve, he was sent to a grammar school in Belfast to learn Latin and Greek. In 1744 he enrolled at [[Glasgow University]] to study arts, subsequently changing, to study medicine. There, [[William Cullen]] was his instructor in chemistry, and the relation between the two soon became that of professor and assistant rather than of master and pupil. <font size=1>[[Joseph Black|['''more...''']]]</font>
While the idea of a parasitic worm goes far back in biology, the term appears to have first been used as, as a concept in computing, in [[John Brunner]]'s 1975 science fiction novel, ''[[Shockwave Rider]]''.  Actual software, under tightly controlled conditions, was developed in 1981-1982. <font size=1>[[Worm (computers)|['''more...''']]]</font>
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Revision as of 21:17, 24 February 2009


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Article of the Week [ about ]

The ether (also spelled[1] aether) was a concept in physics made obsolete in 1905 by Einstein's theory of special relativity.

The idea of an ether was introduced into science by Descartes in Principia philosophiae (1644). Until that time, forces between two bodies that are not in direct contact were assumed to act through space—by action at a distance. Descartes replaced this explanation by one based on an intermediate medium (ether) consisting of vortices that transmit forces between bodies at a distance.

The ether concept became especially predominant in the 19th century by the work of Young and Fresnel who revived Huygens' wave theory of light. They replaced Newton's light corpuscles by waves propagating through the ether. In order to explain stellar aberration, first observed in the 1720s and then shown to be caused by the velocity of the earth relative to the velocity of Newton's light corpuscles, Young (1804) assumed ether to be in a state of absolute rest. Maxwell showed in the 1860s that light waves are electromagnetic waves transverse (perpendicular) to the direction of the propagation of the waves. Following Young and Fresnel, Maxwell assumed that electromagnetic waves are vibrations of the ether. [more...]

New Draft of the Week [ about ]

In computer and network security, a worm is a form of malware that, once it activates inside a victim's computer, can replicate and propagate itself without further user activity. Worms often take up valuable memory and network bandwidth, which can cause a computer to stop responding, and can also allow attackers to gain unauthorized remote control of one or more computers.

While the idea of a parasitic worm goes far back in biology, the term appears to have first been used as, as a concept in computing, in John Brunner's 1975 science fiction novel, Shockwave Rider. Actual software, under tightly controlled conditions, was developed in 1981-1982. [more...]

  1. Generally speaking the spelling "ether" is more modern than "aether". Note, however, that two Americans, A. A. Michelson and E.W. Morley, spelled it as "ether" as early as 1887.