Bookbinding and the Conservation of Books
A Dictionary of Descriptive Terminology

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viscosity

1. That property of a fluid manifest as a resistance to flow and measured by the tangential force per unit area of either of two horizontal planes at unit distance apart, one of the planes moving with unit velocity relative to the other, the space between being occupied by the flowing liquid. If the velocity of flow is proportional to the force applied, the fluid is said to exhibit Newtonian behavior; however, many colloidal dispersions and suspensions display anomalous non-Newtonian flow, i.e., the velocity of flow is not proportional to the force applied.

Viscosity diminishes as temperature rises, often by about 2% per degree C; it also increases with an increase in pressure.

2. That property of a cellulose paper pulp, or other polymer, expressed by the viscosity of a solution of the material in a suitable solvent and under specified conditions. Viscosity in this respect is related to the strength, as well as other properties of the paper pulp fibers. (17 , 72 , 195 , 309 )




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