Bingham yield stress

Adsorption on Kaolinite. For kaolinite, the polymer adsorption density is strongly dependent on the solid/liquid ratio, S/L, of the clay suspension. As S/L increases, adsorption decreases. This S/L dependence cannot be due totally to autocoagulation of the clay particles since this dependence is observed even in the absence of Ca2+ at pH 7 and at low ionic strength where auto-coagulation as measured by the Bingham yield stress is relatively weak (21). Furthermore, complete dispersion of the particles in solvent by ultra-sonication before addition of... 

Figure 6.11 The Bingham yield stress as a function of volume fraction for the system with the potential shown in Figure 5.9...

Figure 6.12 Plot of the Bingham yield stress versus the concentration of cis-poly (iso-prene) added to a latex in dodecane (system HK4 with

Figure 5.19 The specific volume offilter cake, sediment volume, and Bingham yield stress of sodium montmorillonite sols as a function of the NaCI concentration. From van Olphen [1], Copyright 1977, Wiley-lnterscience.

Increasing the levels of Cab-O-Si1 and/or pigment in the print paste does not alter the plastic viscosity, but it increases the Bingham yield stress. The paste thus has a greater "shear thinning" character at higher Cab-O-Sil or pigment levels. 

At high shear rates, when the gel network is broken down, the dominant viscoelastic contribution comes from floes that break apart and reform rapidly. For such dispersions, at modest particle volume fractions, a typical relationship between steady-state shear stress a and shear rate y is shown in Fig. 7-24 (Friend and Hunter 1971). Note that at the highest shear rates, the y-a relationship appears to be linear, but the extrapolation of this linear relationship to zero shear rate intersects the stress axis at a positive value, as, rather than zero. This intercept is called the Bingham yield stress, derived from the Bingham equation for shear stress (Friend and Hunter 1971) ... 

The second equality is obtained by using Eq. (7-lla) for Wmin- Equation (7-33) predicts that Ob should scale with particle volume fraction as zeta potential as cTg ft cTg o — where crg,o is the Bingham yield stress at zero zeta potential, and is a constant. These scalings have been observed in several experiments (Firth 1976). 

The basal planes and edges in clay minerals have different acid-base properties. PZCs of the edge (at pH 8) and of the Al layer (at pH 6) of kaolinite are reported in [761], The lEP of the edge surface of Na-kaolinite at pH 7.3 was obtained [762] as the intersection point of Bingham yield stress (pH) curves at various ionic strengths. 

At zero shear rate, the network yield stressOn equalsOo the yield stress obtained by extrapolation of the shear rate-shear stress data to zero shear rate. The Bingham yield stress (Ob) can be obtained by extrapolation of only the linear portion of the shear rate-shear stress diagram to zero shear rate. 

Figure 28. Bingham yield stress variation with solid volume fraction for weakly flocculated systems of different particle sizes and different layer of thickness (173,).

One unique scaling behavior has been uncovered in this chapter for the low shear limit viscosity, equation 64, Bingham yield stress, equation 65, and the compressive yield stress-osmotic pressure, equation 74, for... 

Despite the low levels of adsorption, the anionic polymers have a significant effect on the rheology of the bentonite suspensions. Figure 22 shows the dependence of the Bingham yield stress rG on bentonite concentration with and without added dispersants. Rabaioli et al. found the dependence of rG on the volume fraction of bentonite 0 to be... 

Figure 22. Dependence of Bingham yield stress and storage modulus (G ) on bentonite content of bentonite suspensions in the presence of various additives. (Reproduced with permission from reference 78. Copyright 1993 Society of Petroleum Engineers.)...

Figure 8.3 Basic types of rheological behaviour (a) Newtonian, (b)—(c) non-Newtonian /(b) shear thickening, (c) shear thinning, A) pseudoplastic. (e) plastic (Bingham plow), in which o0 is the yield stress and On is the Bingham yield stress/.

Figure 6.14 Bingham yield stress of clay gels as a function of the amount of NaCi added. (Adapted from van Olphen [44]. Copyright (1977), reproduced with permission of Wiiey-Interscience.)...

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