The Physiological Principle of Minimum Work

نویسنده

Cecil D. Murray

چکیده

P. S. Bauer t has recently questioned the vMidity of the Physiological Principle of Minimum Work as formulated and applied by me 2 to certain problems concerning the efficiency of operation of the oxygen transport system in man. In contrast to his opinions or the implications which he makes in respect to my work, I reply that this principle should not, and does not rest upon any principle of physics which applies, like the Principle of Least Action (no mention of which was made in my papers), exclusively to ideal conservative systems. Poiseuille's law of flow was used as the simplest approximation to conditions obtaining in capillaries, and the gravitational factor (especially for a man in the basal state and lying down) was neglected as one of secondary magnitude compared to those dealt with in the general problem. Some elementary procedures in calculus, mechanics, and graphical analysis were used in solving the purely mathematical portions of certain problems, but these were simply the ordinary working tools of applied mathematics. Although supported by many analogies and general experience, the validity or "justification" of the Physiological Principle of Minimum Work rests primarily upon the approximate consistency established between theory and certain facts of observation. The principle merely states that in many cases and especially in the circulation of the blood the cost of actual operation of living systems tends to be a minimum and that cost is to be measured in units, like the calorie and the erg, which have dimensions equivalent to those of work.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Pontryagin's Minimum Principle for Fuzzy Optimal Control Problems

The objective of this article is to derive the necessary optimality conditions, known as Pontryagin's minimum principle, for fuzzy optimal control problems based on the concepts of differentiability and integrability of a fuzzy mapping that may be parameterized by the left and right-hand functions of its $alpha$-level sets.

متن کامل

Dynamic Load Carrying Capacity of Flexible Manipulators Using Finite Element Method and Pontryagin’s Minimum Principle

In this paper, finding Dynamic Load Carrying Capacity (DLCC) of flexible link manipulators in point to-point motion was formulated as an optimal control problem. The finite element method was employed for modelling and deriving the dynamic equations of the system. The study employed indirect solution of optimal control for system motion planning. Due to offline nature of the method, many diffic...

متن کامل

Canonical thermostatics of ideal gas in the frame work of generalized uncertainty principle

The statistical consequences of minimal length supposition are investigated for a canonical ensemble of ideal gas. These effects are encoded in the so-called Generalized Uncertainty Principle (GUP) of the second order. In the frame work of the considered GUP scenario, a unique partition function is obtained by using of two different methods of quantum and classical approaches. It should be noti...

متن کامل