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Systems of Many Particles

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Intermediate Physics for Medicine and Biology
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Abstract

This chapter develops a microscopic, statistical view of temperature, heat, work, and the laws of thermodynamics. A key concept is the Boltzmann factor, relating the thermal population of microstates to their energy, and its related concept the Nernst equation. The principle of equipartition of energy leads us to an analysis of the Brownian motion of small particles immersed in a fluid. When two systems can exchange particles as well as energy, the chemical potential governs their behavior. The Gibbs free energy is used to describe chemical reactions that take place at constant temperature and pressure. It is closely related to the chemical potential.

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Notes

  1. 1.

    In computational biology, a mole of differential equations is sometimes called a leibniz (Huang and Wikswo 2004). Solving for the motion of each water molecule in a cubic millimeter of blood requires solving 0.16 millileibniz of equations.

  2. 2.

    Many excellent introductory textbooks on thermodynamics and statistical mechanics exist, such as those by Reif (1994) and Schroeder (1993). To learn more about how thermodynamics is applied to biological problems, see Haynie (1994).

  3. 3.

    A good book on probability is Weaver (1991).

  4. 4.

    A system is that part of the universe that we choose to examine. The surroundings are the rest of the universe. The system may or may not be isolated from the surroundings.

  5. 5.

    There is a subtlety about the meaning of average that we are glossing over here. If we take a whole ensemble of identical systems, which were all prepared the same way, and measure \(n\) in each one, we have the ensemble average \(\bar {n}\). This is calculated in the way described in Appendix G. If we watch one system over some long time interval, as in Fig. 3.4, we can take the time average \(\left \langle n\right \rangle \). It is taken by recording values of \(n\) for a large number of discrete times in some interval. Strictly speaking, an equilibrium state is one in which the ensemble average is not changing with time.

  6. 6.

    A more detailed discussion of equilibrium states is found in Reif (1994).

  7. 7.

    For a more detailed discussion of these assumptions, see Reif (1994, Chap. 3).

  8. 8.

    In thermodynamics and statistical mechanics, equilibrium and steady state do not mean the same thing. Steady state means that some variable is not changing with time. The concentration of sodium in a salt solution flowing through a pipe could be in steady state as the solution flowed through, but the system would not be in equilibrium. Only a few microstates corresponding to bulk motion of the fluid are occupied. In other areas, such as feedback systems, the words equilibrium and steady state are used almost interchangeably.

  9. 9.

    If \(\Omega \) is a continuous function of \(U\), then \(\Omega (U)dU\) is actually the number of states wih energy between \(U\) and \(U+dU\). We ignore this distinction. For a discussion of it, see Chap. 3 of Reif (1994).

  10. 10.

    A more detailed justification of this is found in earlier editions of this book, in texts on statistical mechanics, or on the web site associated with this book.

  11. 11.

    In this book, \(N\) represents the number of particles, and the chemical potential has units of energy per particle. In other books it may have units of energy per mole.

  12. 12.

    An ideal solution is defined in Sect. 3.18.

  13. 13.

    There are multiple pathways in glucose respiration. The 36 is approximate.

  14. 14.

    See also Hildebrand and Scott (1981), p. 17 and Chap. 6.

  15. 15.

    Extensive work has been done on solutions for which these assumptions are not true. See Hildebrand and Scott (1981); Hildebrand et al. (2000).

  16. 16.

    The fact that there is only one microstate because of the indistinguishability of the particles is called the Gibbs paradox (Reif 1998).

References

  • Atkins PW (1994) The 2nd law: energy, chaos and form. Scientific American, New York

    Google Scholar 

  • Cook G, Dickerson RH (1995) Understanding the chemical potential. Am J Phys 63(8):737–742

    Google Scholar 

  • Denny MW (1993) Air and water: the biology and physics of life’s media. Princeton University Press, Princeton

    Google Scholar 

  • Haynie DT (2008) Biological thermodynamics, 2nd edn. Cambridge Univ Press, Cambridge

    Google Scholar 

  • Hildebrand JH, Prausnitz JM, Scott RL (1970) Regular and related solutions: the solubility of gases, liquids, and solids. Van Nostrand Reinhold, New York

    Google Scholar 

  • Hildebrand JH, Scott R L (1964) The solubility of nonelectrolytes, 3rd edn. Dover, New York

    Google Scholar 

  • Huang S, Wikswo J (2006) Dimensions of systems biology. Rev Physiol Biochem Pharmacol 157:81–104

    Google Scholar 

  • Press WH, Teukolsky SA, Vetterling WT Flannery BP (1992) Numerical recipes in C: the art of scientific computing, 2nd edn., reprinted with corrections. Cambridge University Press, New York

    Google Scholar 

  • Reif F (1964) Statistical physics. Berkeley physics course, vol 5. McGraw-Hill, New York

    Google Scholar 

  • Reif F (1965) Fundamentals of statistical and thermal physics. McGraw-Hill, New York

    Google Scholar 

  • Rossi-Fanelli A, Antonini E (1958) Studies on the oxygen and carbon monoxide equillibria of human myoglobin. Arch Biochem Biophys 77(478):478–492

    Google Scholar 

  • Schroeder DV (2000) An introduction to thermal physics Addison Wesley Longman, San Francisco

    Google Scholar 

  • Schwartz D, Mayaux MJ (1982) Female fecundity as a function of age: results of artificial insemination in 2193 nulliparous women with azoospermic husbands. N Engl J Med 306(7):404–406

    Google Scholar 

  • Weaver W (1963) Lady luck: the theory of probability Anchor, Garden City

    Google Scholar 

  • Weaver WD (1982) Ventricular defibrillation—a comparative trial using 175-J and 320-J shocks. N Engl J Med 307:1101–1106

    Google Scholar 

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Correspondence to Russell K. Hobbie .

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Hobbie, R., Roth, B. (2015). Systems of Many Particles. In: Intermediate Physics for Medicine and Biology. Springer, Cham. https://doi.org/10.1007/978-3-319-12682-1_3

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