(2) Influence of

coefficient of viscosity on the floor

At higher shear rates there is no significant variation and the

coefficient of viscosity is almost constant over the entire range of shear rate.

As a first approximation, the following expression (Barus equation) can be used to determine the parameter, [[beta].sub.p], known as the pressure

coefficient of viscosity:

In the exponential relations (15, 16) [beta] is the pressure

coefficient of viscosity, P stands for the gauge pressure, [alpha] means the temperature

coefficient of viscosity, and T and [T.sub.r] are tested and reference temperatures, respectively.

It was noted that the concentration

coefficient of viscosity, [Psi], was a considerably negative value, as expected.