False viscosity effect

The major solution and dope properties that are evaluated when studying flake properties are solution haze and color, the false viscosity effect, and filterability of the acetone dopes. 

Acetone dope properties False viscosity effect (%) 150 80 50... 

It is quite obvious that the attempt at separating the viscosity effect and the damping effect just explained is to be considered only as a provisional step in the investigation of this domain. So too much weight should not be attached to the results which may on a closer examination prove more or less false. It is contemplated to make the influence of the magnetic field on a turbulent flow the subject of a subsequent investigation. 

Thus, equation 3.127, which includes three parameters, is effectively a combination of equations 3.121 and 3.125. It is sometimes called the generalised Bingham equation or Herschel -Bulkley equation, and the fluids are sometimes referred to as having/n/re body. Figures 3.30 and 3.31 show shear stress and apparent viscosity, respectively, for Bingham plastic and false body fluids, using linear coordinates. 

A ratio affects the yield stress, while plastic viscosity is not much affected. These effects are much less pronounced for a less reactive cement, but with the lowest G-H or A ratio, false set can occur [130-132]. An increased fineness of cement increases the effect of the G-H or A ratio. The effect has been found to be most pronounced with melamine-based superplasticizers [130, 133]. 

The uncontrolled variation in the gypsum-hemihydrate or soluble anhydrite ratio (G-H or A) that occurs during production, storage and transportation of cement can cause compatibility problems with certain superplasticizers, particularly a reduction in workability. The extent of the reduction on workability properties is dependent on the G-H ratio (ranging from 80 20% to 20 80%), level of C A and alkalis present in the cement and the fineness of the cement. For the most reactive type of cement with a high content of both C A and alkalis, a reduced G-H or A ratio affects the yield stress, while piastre viscosity is not much affected. These effects are much less pronounced for a less reactive cement, but with the lowest G-H or A ratio, false set can occur [130-132], An increased fineness of cement increases the effect of the G-H or A ratio. The effect has been found to be most pronounced with melamine-based superplasticizers [130, 133],... 

Thixotropic adj (1) A liquid or dispersion that exhibits a reduction in viscosity with time at constant shear stress, opposite effect is rheopectic (not to be confused with pseudoplastic, reduction of viscosity with shear stress). (2) A term that describe full-bodies material which undergoes a reduction in viscosity when shaken, stirred, or otherwise mechanically disturbed and which readily recovers the original full-bodied condition on standing. See Body False Body. 

---