Coaxial cylindrical viscometer

However, Thomas and Dimnill (1979) studied the effect of shear on catalase and urease activities by using a coaxial cylindrical viscometer that was sealed to prevent any air-liquid contact. They found that there was no significant loss of enzyme activity due to shear force alone at shear rates up to 106 sec-1. They reasoned that the deactivation observed by Charm and Wong (1970) was the result of a combination of shear, air-liquid interface, and some other effects which are not fully understood. Charm and Wong did not seal their shear apparatus. This was further confirmed, as cellulase deactivation due to the interfacial effect combined with the shear effect was found to be far more severe and extensive than that due to the shear effect alone (Jones and Lee, 1988). 

Viscometers include the capillary, coaxial cylindrical, cone-and-plate, falling-ball type, etc. The capillary and, to a lesser extent but of increasing importance, the coaxial cylindrical viscometers, in numerous modifications, are the two most commonly used in scientific laboratories. 

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