Typical rheogram

Typical rheograms representing the behaviour of various types of generalized Newtonian fluids are shown in Figure 1.2. 

Fig. 6 Typical rheogram for a shear thinning (a), shear thickening (b), and a Casson body (c).

Figure 8. Typical rheograms of simple bentonite-polymer (CMC) drilling fluids. Drilling fluids contain 20.6 g/L bentonite and variable polymer concentrations (shown in g/L). (Reproduced with permission from reference 32. Copyright 1993 Society of Petroleum Engineers.)...

Figure 14.7 A Typical rheogram of suberin at 20°C. A increasing stress B constant stress C decreasing stress. (Reprinted from Reference [78], with permission from Elsevier.)...

Solutions of tetraethylammoniumperfluorooctanesulfonate (C8Fi7S03NEt4) were studied with the HF rheometer. A typical rheogram is shown in Fig. 11.38. The measurement was carried out on a 90 mM solution with the 50 mM gap in the frequency range above 10 Hz. Below 10 Hz a Bohlin CS10 rheometer with a cone plate geometry was employed. 

As an example, let us consider a typical response produced by stretching a sample of a vulcanised rubber. The components of the stress that we have to consider are the normal stresses axx, [Pg.15]

Figure 7 shows the rheograms (shear stress versus shear rate plots) of a typical emulsion system at different values of dispersed-phase concentration. The volume-surface mean diameter of the oil droplets for the system shown is 10 xm. For a given concentration, the variation of log t against log 7 is linear, a result indicating that the emulsions follow a power law (eq 2). 

The relationships between stress, strain, and viscosity are usually depicted in the so-called rheograms. In the pharmaceutical sciences, typical flow curves are presented, i.e., x = /(y). In the engineering sciences, the viscosity is usually drawn as a function of the shear stress [vj = f(x)]. This is sensible as most viscometers control the shear stress applied rather than the shear strain rate. However, the entity of interest is the viscosity as a function of the shear strain rate [i] = /(y)]. 

It was found [95] that the master rheograms for each of filled systems was no different from that for the unfilled systems over a broad range of shear rates. Only in the very low-shear-rate region, the master curve is not unique due to the yield stress behavior, which is known to occur for filled systems as can be seen from one typical curve shown in Fig. 4.44. This aspect was depicted [95] only for HDPE, where a clear fork was shown to exist in the low-shear-rate region. Although in other curves the forks were not shown [95], it does not imply their nonexistence. In fact, if sufficient data in the low-shear region on filled systems was available, then the fork would be present in all the curves. However, the matter of prime importance is that the master curve in the... 

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