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Mailing List complex-science@necsi.org Message #9653 | |
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| Thermodynamic systems divide into three classes, depending on whether the system is exchanging energy and/or matter with its environment: Table 1. Three classes of thermodynamic systems _____________________________________________________________________ Thermodynamic Systems ______________________________________________________ Exchange Isolated Closed Open _____________________________________________________________________ Energy No Yes Yes - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Matter No No Yes - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Example Adiabatic Refrigerator Biosphere systems Thermometer Cells Universe* Heating pad Animals Engines - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Alternative Microcanonical Canonical Grand canonical names ensembles ensemble ensemble ______________________________________________________________________ *The Universe by definition doesn't even have any boundary and hence cannot exchange any matter or energy with it. It is important to note that many physicists and other scientists do not differentiate between "closed" and "isolated" thermodynamic systems. When they say "closed" system, they usually mean "isolated systems". Hope this table helps. Sung > Do not know, first have to name what an isolated system is, then what a > system is, then define enthropy, then see the math used to produce the > laws, > then see what these math have to do with my result and what they express , > check also Prigogine's formulations and to what they are refering to , and > then insert the data to biology. The Clausius formulations where a lot way > back and spoke of different things? have to check this also the way it > altered? in todays formulas... > Anyway thanks for the hints. > > Thanasis > 2008/7/10 <complex-science@necsi.org>: > >> 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 >> > >> >> >> -------------------------------------------------- >> For information about this discussion group visit >> http://necsi.org/discuss/discuss.html >> > |
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