Rate of work hypothesis

In addition to these equations, we employ a rate of work hypothesis, which is effectively a balance of energy with thermal effects assumed to be negligible. Thus we consider... 

Following Leslie [175], a rate of work hypothesis will now be invoked. This assumes that the rate at which forces and moments do work on a volume of nematic will be absorbed into changes in the nematic energy wp (cf. equations (2.49) and (2.50)) or the kinetic energy, or will be lost by means of viscous dissipation. The rate of work postulate is taken to be... 

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