Casson equation

Casson-Asbeck plots Casson equation Casson plots CASS test Castable urethanes Castanin... 

Another model is the Casson equation (13), which is useful in estabHshing the flow characteristics of inks, paints, and other dispersions. An early form of this expression (eq. 1) was modified (14) to give equation 2. 

Fig. 3. Examples of Casson plots (viscosity) vs (shear rate). The Casson equation is 77 = 77), + Tq 7...

Taking into account all the various stipulations, we shall still assume that yield stress has a certain physical meaning and it can be measured by a stationary method proceeding from the flow curve. However, to measure the points and achieve such a clear pattern as shown in Fig. 1 is not always convenient and it is rather labor-consuming. In practice, it is convenient to use a semi-analytical procedure. It is based on the utilization of an equation for flow curves taking into account the existence of yield stress. The most widespread equation of this kind is the Casson equation. It assumes that the x(y) dependence for filled polymers is expressed in the following way ... 

Fig. 4. Diagram illustrating the method for determining a yield stress by constructing a flow curve in the coordinates of the Casson equation. The content of the filler is more for curve 2 than for curve 1...

Given that the flow properties of the puree can be described by the Casson equation ... 

The Casson equation is frequently applied to describe shear yielding in concentrated Newtonian suspensions [14] ... 

The Casson equation is a particular form of equation 3.122 which applies to a number of foodstuffs as well as tomato puree. 

Using the Casson equation the two terms in the right hand side bracket can be written as ... 

It is clear from the above discussion that the rheological properties of FCOJ will depend on the °Brix, pulp content, size and shape of the pulp particles, and pectin content of FCOJ sample, and the temperature at which the data were obtained. Carter and Buslig (1977) studied particle size distribution in commercial frozen FCOJ samples. Mizrahi and coworkers conducted systematic studies on FCOJ that they described as a physicochemical approach (Mizrahi and Berk, 1970 Mizrahi and Firstenberg, 1975 Mizrahi, 1979). They used a modified Casson equation to describe the flow behavior of FCOJ. 

Chevalley, J. 1991. An adaptation of the Casson equation for the rheology of chocolate.. 7 Texture Stud. 22 219-229. 

Figure 9.9 shows that yield stress increases with a filler volume fraction. Polymer type does not play a significant role here since neither polymer interacts with filler. Small additions of carbon black increase yield stress rapidly. Several equations are used to describe yield stress. The Casson equation is the most frequently used. In this equation the yield stress of a filled system depends on the yield stress and the viscosity of the matrix and on the applied shear rate. ... 

Four models (Herschel-Bulkley, Casson, Bingham, and power law) were used to fit the experimental data and to determine the yield stress of the slurries. Table 1 list the results obtained for the different parameters used to fit the experimental data of fermentation suspensions at the various concentrations. The Herschel-Bulkley model fits the data satisfactorily over the whole experimental range at 10 to 20% solids concentration. On the other hand, the Bingham and Casson equations are in excellent agreement with results of the enzymatic suspension and fermentation broth testing at 10 and 20%, respectively (Table 1). The results of the power law model (n and K) were compared to those power law parameters obtained with the impeller method. The Herschel-Bulkley, Bingham, and the... 

There are several methods for determining a. Among these is the modified Casson equation [Utracki, 1982] ... 

The Casson equation (equation 5.1) is often used to describe the rheology of liquid chocolates and couvertures. The relation between the shear stress (a) and the shear rate (y) depends on two parameters the yield stress, Oy, i.e. the shear stress required to initiate flow, and the plastic viscosity, i.e. the viscosity after yield. 

The use of the modified rheoviseometer, which enables handling of unstable mineral suspensions, has recently revealed that the Casson Equation fits the flow curve for the magnetite suspension better than the typically used Bingham plastic model [see the special issue of Coal Preparation entirely devoted to magnetite dense media [Coal Preparation ( 99Qi). 8(3 ).]... 

The Casson equation is sometimes a very successful alternative approach ... 

The results, using data on P. chrysogenum, are shown in Fig. 6.55. As can be seen, the power of x seems to be somewhat higher than 2, according to Equ. 6.178. Rods et al. (1974) found that the morphology index decreased during batch fermentation. As a consequence of this approach, the parameters and To in the Casson equation can be expressed as dependent on (5 ... 

Casson equation n. Rheology expression used to relate share rate, viscosity, and at infinite shear rate for dispesrsions (pigment coatings, etc.). Patton TC (1979) Paint flow and pigment dispersion a... 

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