Factor viscosity

For plastics other than the easy flow materials referred to above, it would be normal to apply a factor to allow for the higher viscosity. Typical viscosity factors are given below. 

This is also the flow ratio, so from Fig. 4.42 the mean effective pressure is 50 MN/m. Applying the viscosity factor, etc as above, then... 

The results of [91] supply ample evidence in support of this qualitative picture. The authors determined the baric viscosity factor b = [0 In j/(0P)-1] T (where t] is viscosity, P is pressure) for impact-resistant polystyrene filled with antimony trioxide. The viscosity piezocoefficient is known to be related to the free volume. A very simple formula for this relationship has been proposed in [92] in this form ... 

Effect of storage on viscosity. Factors such as the method of storing undissolved nitrocellulose affect the viscosity of its solutions. It has been established (Kanamaru [73]) that nitrocellulose kept in a polar liquid, e.g. water, alcohol, and tested for viscosity at stated periods by dissolving samples in acetone, shows for the first few days a rather rapid increase in viscosity, which gradually becomes slower. If cellulose is stored in a non-polar liquid, such as carbon tetrachloride, or petroleum ether, then the viscosity of solutions remains unchanged or increases only very slightly. 

Dintenfass, L. Blood Microrheology Viscosity Factors in Blood Flow,... 

The viscosity power factor for lVRe = 290 is found to be 1.2fromFig. 12.2. The power number for the impeller described in the example is the viscosity factor times the turbulent power number (from the previous step) Np = 1.2(1.43) = 1.72. 

The values of t] and x cannot be determined directly and, therefore, Benbow, Oxley, and Bridgwater, introduced the term jS, the die land viscosity factor, to replace r /x, as in Eq. (13) ... 

The Relevance List in Table 1 reflects certain assumptions used to simplify the model, namely, that there are short-range interactions only and no viscosity factor (and therefore, no Reynolds number). 

The index for the Reynolds number is generally taken as 0.8. That for the Prandtl number can range from 0.3 for cooling to 0.4 for heating. The index for the viscosity factor is normally taken as 0.14 for flow in tubes, from the work of Sieder and Tate (1936), but some workers report higher values. A general equation that can be used... 

The elementary steps in the LH theory are the deposition of the first stem (rate constant An), deposition of subsequent stems (A), and removal of a stem (B). The individual rate constants are of the form ft exp[—(barrier)// ], where ft contains the viscosity factor etc. Hence,... 

Why does a denatured protein typically have a higher viscosity factor than a folded protein ... 

A folded protein is more spherical than a denatured protein and a sphere is expected to have a lower viscosity factor than non-spherical shapes. This is discussed in more detail in Chapter 27 and shown clearly in Fig. 27.11. 

Our first objective is to determine Y. Later we analyze our results to define cases when one of the two viscosity factors is predominant. Equation 4 becomes... 

It is known that observing in radical polymerization processes change of chains bimolecular termination rate constant kt (reaction is controlled by diffusion) is often connected with the change of reaction solution viscosity [4, 5] which is naturally increased by the accumulation of reaction product in system - polymer. And then the contribution of viscosity factor is significant and that is why the reduction of rate constant of chains bimolecular termination kt is observed first of all. Fiowever, for a number of monomers it is necessary to consider the factor of influence of initial reaction solution viscosity on polymerization parameters. 

Then obviously considering this factor the studied reaction of polymerization is characterized by the first order by monomer in the whole investigated interval of MAG monomer concentration (Figure 6), in spite of observing micro-heterogeneity for given system. In the case of AG polymerization (Figure 7) even with correct for "viscosity" factor reaction order by monomer concentration is more than one and is equal to 1,5. 

Figure 1. Block diagram of a model for the control of erythropoiesis (HbO), oxyhemoglobin concentration Vi, viscosity factor (HbO), effective oxyhemoglobin concentration R, rate of erythropoietin release (E), plasma erythropoietin concentration E0, normal plasma erythropoietin concentration V , distribution volume for erythropoietin P, rate of hemoglobin production MT, erythrocyte maturation time L, rate of hemoglobin loss TH, total circulating hemoglobin (Hb), blood hemoglobin concentration Vb, blood volume Vp, plasma volume Vp0, normal plasma volume Vpf, steady-state hypoxic plasma volume MCV, mean corpuscular volume MCH, mean corpuscular hemoglobin k, constant...

Since oxygen input to tissue depends upon tissue blood perfusion as well as oxyhemoglobin concentration, the latter was multiplied by a viscosity factor to account for perfusion changes resulting from the very high hematocrits that occur with severe hypoxia. Hematocrit was calculated from total red cell volume and total blood volume. The viscosity factor (Vi) was calculated from the relationship shown in Equation 5. 

The constants Ke and K7 were selected to produce a viscosity factor of 1.0 for a particular hematocrit (Hctk) and a preselected Vi when the hematocrit is 1.0. The viscosity factor has no effect when the hematocrit is less than Hctk (normally 0.5) and maximum effect when the hematocrit equals 1. The viscosity effect was incorporated into the erythropoietic feedback system by multiplying Vi by the oxyhemoglobin concentration to produce an effective oxyhemoglobin concentration. This effective oxyhemoglobin concentration was then used to determine the rate of erythropoietin release as described earlier. 

Figure 9. Experimental data (2) and the model results from mice exposed cortr tinuously to a total pressure of 360 mm Hg. Each data point is the average of values obtained from nine mice. Different symbols represent different runs. The model responses were obtained with the parameter values listed in Table I. The solid line was obtained with the viscosity factor effective only when hematocrit was greater than 0.6. The broken line was obtained with no viscosity...

The most speculative of the relationships in the original model is the viscosity factor (Vi)—an oversimplification that accounts for a combination of effects. The inclusion in the model of the factor stem cell potentiation to allow for changes in the sensitivity of erythropoietin places less dependence on the viscosity factor to produce a reasonable fit between model response and experimental data. In the original model the viscosity factor took effect when hematocrit was greater than 0.5 (Hctk) and resulted in a viscosity factor (Vi) of 0.8 when the hematocrit equaled 0.75. In the present model Hctk was set at 0.6 so that no viscosity effect occurs until the hematocrit is greater than 0.6. In addition, Ke in Equation 5 is set to produce a viscosity factor of 0.9 when the hematocrit is 0.75. 

The viscosity factor was also taken as responsible for the observed slowing down of the polymerization of DVE-3 when ELNR-70 was added to this monomer (Fig.7). For instance, a five fold decrease of the rate of polymerization of the vinyl ether double bond was noticed in the highly viscous 1 to 10 blend by weight of DVE-3 and ELNR-70. Despite the faster cure, insolubilization of the irradiated sample was not taking place more rapidly when DVE-3 was added to EPI (Fig.8), which means that a certain level of insolubilization requires a higher degree of conversion of the epoxy... 

Let us summarize the obtained results. From the expression for the viscosity of an infinite diluted suspension, it follows that the viscosity factor does not depend on the size distribution of particles. The physical explanation of this fact is that in an infinite diluted suspension W 1), particles are spaced far apart (in comparison with the particle size), and the mutual influence of particles may be ignored. Besides, under the condition a/h 1, we can neglect the interaction of particles with the walls. It is also possible to show that in an infinite diluted suspension containing spherical particles. Brownian motion of particles does not influence the viscosity of the suspension. However, if the shape of particles is not spherical, then Brownian motion can influence the viscosity of the suspension. It is explained by the primary orientation of non-spherical particles in the flow. For example, thin elongated cylinders in a shear flow have the preferential orientation parallel to the flow velocity, in spite of random fluctuations in their orientation caused by Brownian rotational motion. 

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