'''Rudolf Julius Emanuel Clausius''' ({{IPA-de|ˈʁuːdɔlf ˈklaʊ̯zi̯ʊs}};<ref>{{cite book|author1=Dudenredaktion|last2=Kleiner|first2=Stefan|last3=Knöbl|first3=Ralf|year=2015|orig-year=First published 1962|title=Das Aussprachewörterbuch|trans-title=The Pronunciation Dictionary|url=https://books.google.com/books?id=T6vWCgAAQBAJ|language=German|edition=7th|location=Berlin|publisher=Dudenverlag|isbn=978-3-411-04067-4|pages=280, 744}}</ref><ref>{{cite book|last1=Krech|first1=Eva-Maria|last2=Stock|first2=Eberhard|last3=Hirschfeld|first3=Ursula|last4=Anders|first4=Lutz Christian|title=Deutsches Aussprachewörterbuch|trans-title=German Pronunciation Dictionary|url=https://books.google.com/books?id=E-1tr_oVkW4C&q=deutsches+ausspracheworterbuch|language=German|year=2009|publisher=Walter de Gruyter|location=Berlin|isbn=978-3-11-018202-6|pages=416, 884}}</ref> 2 January 1822 – 24 August 1888) was a [[Germany|German]] [[physicist]] and [[mathematician]] and is considered one of the central founders of the science of [[thermodynamics]].<ref>{{Citation | author=Cardwell, D.S.L. | title=From Watt to Clausius: The Rise of Thermodynamics in the Early Industrial Age | location=London | publisher=Heinemann | year=1971 | isbn=978-0-435-54150-7}}</ref> By his restatement of [[Nicolas Léonard Sadi Carnot|Sadi Carnot]]'s principle known as the [[Carnot cycle]], he gave the [[theory of heat]] a truer and sounder basis. His most important paper, "On the Moving Force of Heat",<ref name="Theory of Heat"/> published in 1850, first stated the basic ideas of the [[second law of thermodynamics]]. In 1865 he introduced the concept of [[entropy]]. In 1870 he introduced the [[virial theorem]] which applied to [[heat]].<ref>{{cite journal | last = Clausius | first = RJE | year = 1870 | title = On a Mechanical Theorem Applicable to Heat | journal = Philosophical Magazine |series=4th Series | volume = 40 | pages = 122–127}}</ref>
'''Rudolf Julius Emanuel Clausius''' ({{IPA-de|ˈʁuːdɔlf ˈklaʊ̯zi̯ʊs}};<ref>{{cite book|author1=Dudenredaktion|last2=Kleiner|first2=Stefan|last3=Knöbl|first3=Ralf|year=2015|orig-year=First published 1962|title=Das Aussprachewörterbuch|trans-title=The Pronunciation Dictionary|url=https://books.google.com/books?id=T6vWCgAAQBAJ|language=de|edition=7th|location=Berlin|publisher=Dudenverlag|isbn=978-3-411-04067-4|pages=280, 744}}</ref><ref>{{cite book|last1=Krech|first1=Eva-Maria|last2=Stock|first2=Eberhard|last3=Hirschfeld|first3=Ursula|last4=Anders|first4=Lutz Christian|title=Deutsches Aussprachewörterbuch|trans-title=German Pronunciation Dictionary|url=https://books.google.com/books?id=E-1tr_oVkW4C&q=deutsches+ausspracheworterbuch|language=de|year=2009|publisher=Walter de Gruyter|location=Berlin|isbn=978-3-11-018202-6|pages=416, 884}}</ref> 2 January 1822 – 24 August 1888) was a [[Germany|German]] [[physicist]] and [[mathematician]] and is considered one of the central founders of the science of [[thermodynamics]].<ref>{{Citation | author=Cardwell, D.S.L. | title=From Watt to Clausius: The Rise of Thermodynamics in the Early Industrial Age | location=London | publisher=Heinemann | year=1971 | isbn=978-0-435-54150-7}}</ref> By his restatement of [[Nicolas Léonard Sadi Carnot|Sadi Carnot]]'s principle known as the [[Carnot cycle]], he gave the [[theory of heat]] a truer and sounder basis. His most important paper, "On the Moving Force of Heat",<ref name="Theory of Heat"/> published in 1850, first stated the basic ideas of the [[second law of thermodynamics]]. In 1865 he introduced the concept of [[entropy]]. In 1870 he introduced the [[virial theorem]] which applied to [[heat]].<ref>{{cite journal | last = Clausius | first = RJE | year = 1870 | title = On a Mechanical Theorem Applicable to Heat | journal = Philosophical Magazine |series=4th Series | volume = 40 | pages = 122–127}}</ref>
==Life==
==Life==
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* [[Poncelet Prize]] in 1883.
* [[Poncelet Prize]] in 1883.
* Honorary doctorate from the [[University of Würzburg]] in 1882.
* Honorary doctorate from the [[University of Würzburg]] in 1882.
* Foreign Member of the [[Royal Netherlands Academy of Arts and Sciences]] in 1886.<ref>{{cite web|author= |url=http://www.dwc.knaw.nl/biografie/pmknaw/?pagetype=authorDetail&aId=PE00004619 |title=R.J.E. Clausius (1822 - 1888) |publisher=Royal Netherlands Academy of Arts and Sciences |date= |accessdate=21 July 2015}}</ref>
* Foreign Member of the [[Royal Netherlands Academy of Arts and Sciences]] in 1886.<ref>{{cite web|url=http://www.dwc.knaw.nl/biografie/pmknaw/?pagetype=authorDetail&aId=PE00004619 |title=R.J.E. Clausius (1822 - 1888) |publisher=Royal Netherlands Academy of Arts and Sciences |accessdate=21 July 2015}}</ref>
* [[Pour le Mérite for Arts and Sciences]] in 1888
* [[Pour le Mérite for Arts and Sciences]] in 1888
* The lunar crater [[Clausius (crater)|Clausius]] named in his honor.
* The lunar crater [[Clausius (crater)|Clausius]] named in his honor.
Revisionasof08:11,2December2020
German mathematical physicist
"Clausius" redirects here. For the lunar crater, see Clausius (crater).
Clausius was born in Köslin (now Koszalin, Poland) in the Province of PomeraniainPrussia. His father was a Protestant pastor and school inspector,[6] and Rudolf studied in the school of his father. In 1838, he went to the Gymnasiumin Stettin. Clausius graduated from the University of Berlin in 1844 where he had studied mathematics and physics since 1840 with, among others, Gustav Magnus, Peter Gustav Lejeune Dirichlet and Jakob Steiner. He also studied history with Leopold von Ranke. During 1848, he got his doctorate from the University of Halle on optical effects in Earth's atmosphere. In 1850 he became professor of physics at the Royal Artillery and Engineering School in Berlin and Privatdozent at the Berlin University. In 1855 he became professor at the ETH Zürich, the Swiss Federal Institute of Technology in Zürich, where he stayed until 1867. During that year, he moved to Würzburg and two years later, in 1869 to Bonn.
In 1870 Clausius organized an ambulance corps in the Franco-Prussian War. He was wounded in battle, leaving him with a lasting disability. He was awarded the Iron Cross for his services.
His wife, Adelheid Rimpau died in 1875, leaving him to raise their six children. In 1886, he married Sophie Sack, and then had another child. Two years later, on 24 August 1888, he died in Bonn, Germany.[7]
Work
Clausius's PhD thesis concerning the refraction of light proposed that we see a blue sky during the day, and various shades of red at sunrise and sunset (among other phenomena) due to reflection and refraction of light. Later, Lord Rayleigh would show that it was in fact due to the scattering of light, but regardless, Clausius used a far more mathematical approach than some have used.
His most famous paper, Ueber die bewegende Kraft der Wärme ("On the Moving Force of Heat and the Laws of Heat which may be Deduced Therefrom")[8]
was published in 1850, and dealt with the mechanical theory of heat. In this paper, he showed that there was a contradiction between Carnot's principle and the concept of conservation of energy. Clausius restated the two laws of thermodynamics to overcome this contradiction[9] (the third law was developed by Walther Nernst, during the years 1906–1912). This paper made him famous among scientists.
Clausius' most famous statement of thermodynamics second law was published in German in 1854,[10] and in English in 1856.[11]
Heat can never pass from a colder to a warmer body without some other change, connected therewith, occurring at the same time.
During 1857, Clausius contributed to the field of kinetic theory after refining August Krönig's very simple gas-kinetic model to include translational, rotational and vibrational molecular motions. In this same work he introduced the concept of 'Mean free path' of a particle.[12][13][14]
In 1865, Clausius gave the first mathematical version of the concept of entropy, and also gave it its name.[7] Clausius chose the word because the meaning (from Greek ἐν en "in" and τροπή tropē "transformation") is "content transformative" or "transformation content" ("Verwandlungsinhalt").[4][15] He used the now abandoned unit 'Clausius' (symbol: Cl) for entropy.[16]
The landmark 1865 paper in which he introduced the concept of entropy ends with the following summary of the first and second laws of thermodynamics:[4]
The energy of the universe is constant.
The entropy of the universe tends to a maximum.
^Dudenredaktion; Kleiner, Stefan; Knöbl, Ralf (2015) [First published 1962]. Das Aussprachewörterbuch [The Pronunciation Dictionary] (in German) (7th ed.). Berlin: Dudenverlag. pp. 280, 744. ISBN978-3-411-04067-4.
^Krech, Eva-Maria; Stock, Eberhard; Hirschfeld, Ursula; Anders, Lutz Christian (2009). Deutsches Aussprachewörterbuch [German Pronunciation Dictionary] (in German). Berlin: Walter de Gruyter. pp. 416, 884. ISBN978-3-11-018202-6.
^Cardwell, D.S.L. (1971), From Watt to Clausius: The Rise of Thermodynamics in the Early Industrial Age, London: Heinemann, ISBN978-0-435-54150-7
^Huang, Mei-Ling; Hung, Yung-Hsiang; Chen, Wei-Yu (2010-10-01). "Neural Network Classifier with Entropy Based Feature Selection on Breast Cancer Diagnosis". Journal of Medical Systems. 34 (5): 865–873. doi:10.1007/s10916-009-9301-x. ISSN1573-689X. PMID20703622. S2CID6658005.
