Papers Published

  1. Bejan, Adrian, Theory of organization in nature: Pulsating physiological processes, International Journal of Heat and Mass Transfer, vol. 40 no. 9 (1997), pp. 2097 - 2104 [S0017-9310(96)00291-8] .
    (last updated on 2007/04/06)

    This paper shows that thermodynamic optimization provides a common theoretical basis for the existence of the finely tuned frequencies of pulsating processes of animals. In respiration and circulation, the minimization of mechanical power consumption subject to finite contact area and mass transfer (metabolic) rate constraints also explains why frequencies decrease as the body size (M) increases. For example, it is shown that the optimal breathing and heartbeat time intervals should increase as M0.24, which is in excellent agreement with experimental data. It is also shown that the breathing and heartbeat time intervals should be of the same order of magnitude. In ejaculation, the maximization of the mechanical power transmitted to the ejected seminal fluid explains the existence of an optimal bursting time interval. The deterministic method of thermodynamic optimization predicts temporal organization in Nature, and extends thermodynamics to the field of biology.

    Optimization;Mass transfer;Natural frequencies;Physiology;