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Mailing List complex-science@necsi.org Message #9643 | |
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| Thanks, Sung > Very clear! > Best wishes, > > > Loet > > >> -----Original Message----- >> From: complex-science@necsi.org [mailto:complex-science@necsi.org] >> Sent: Tuesday, July 01, 2008 5:47 AM >> To: complex-science@necsi.org >> Subject: How to avoid mis-interpreting the second law of >> thermodynamics >> >> The most general way to express the second law of thermodynamics is in >> terms of the following formalism introduced by Prigogine >> (1917-2003) in >> 1967 [1]: >> >> dS = d_eS + d_iS . . . . . . . . . . . . . . >> . . . . . . (1) >> >> where dS is the overall entropy change experienced by the system under >> consideration, d_eS (i.e., "d subscript e S")is the entropy exchanged >> between the system and its environment, and d_iS is the >> entropy change due >> to irreversible processes occurring within the system such as >> diffusion >> and chemical reactions. >> >> Using Eq. (1), we can express the second law as follows [1]: >> >> "Whenever irreversible processes occur within a system, >> d_iS > 0." . . (2) >> >> Statement (2), when applied to isolated and non-isolated >> (which includes >> both closed and open) systems, leads to the following corollaries: >> >> "The entropy of isolated systems increases with time." . >> . . . . . . (3) >> >> "The entropy of non-isolated system can increase, >> decrease or remain constant with time." . . . . >> .. . . . . (4) >> >> Statement (3) was first articulated by Rudolf Clausius >> (1822-1888) around >> 1867 [1] and is the familiar form in which the second law is usually >> presented in text books, and Statement (4), alhtough obvious from the >> non-equilibrium thermodyanics point of view and most relevant >> to biology, >> is unfortunately less well-known among biologists. >> >> For convenience, these statements of the second law are >> re-iterated in a >> tabular form in Table 1, where the third column represents >> Statement (2), >> the second row and the last column represents Statement (3), >> and the third >> row and the last column represents Statement (4). >> >> >> Table 1. Different meanings of the second law depending >> on whether the >> thermodynamic system under consideration is isolated or non-isolated. >> ____________________________________________________________________ >> >> System d_eS d_iS dS >> ____________________________________________________________________ >> >> Isolated 0 > 0 > 0 >> ____________________________________________________________________ >> >> Non-isolated >> (i.e, closed >, < or = 0 > 0 >, < or = 0 >> or open) >> ____________________________________________________________________ >> >> >> One common error found in biological literature seems to arise from >> conflating d_iS and dS, leading to the erroneous conclusion that the >> entropy of the system under consideration increases with time >> regardless >> of whether or not the system is isolated. The consequence of this >> seemingly minor error in reasoning can be serious and far-reaching in >> biological discourses. >> >> With all the best. >> >> Sung >> >> ___________________________________________ >> Sungchul Ji, Ph.D. >> Department of Pharmacology and Toxicology >> Rutgers Unviersity >> Piscataway, N.J. 08855 >> >> >> >> Reference: >> [1] Kondepudi, D. and Prigogine, I. (1998). Modern >> Thermodynamics: From >> Heat Engines to Dissipative Structures. John Wiley & Sons, >> Chichester. >> P. 88. >> >> >> >> -------------------------------------------------- >> For information about this discussion group visit >> http://necsi.org/discuss/discuss.html >> > > > -------------------------------------------------- > For information about this discussion group visit > http://necsi.org/discuss/discuss.html > |
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