Viscosity deviations

The hydrodynamic shape factor and axial ratio are related (see Eigure 4.18), but are not generally used interchangeably in the literature. The axial ratio is used almost exclusively to characterize the shape of biological particles, so this is what we will utilize here. As the ellipsoidal particle becomes less and less spherical, the viscosity deviates further and further from the Einstein equation (see Eigure 4.19). Note that in the limit of a = b, both the prolate and oblate ellipsoid give an intrinsic viscosity of 2.5, as predicted for spheres by the Einstein equation. 

By comparison of the dynamic viscosity expressions without and with internal viscosity [see Eqs. (3.1.15) and (3.3.16), respectively], we see that in the former case the sum tends to zero for large co, unlike in the latter we conclude that in the presence of internal viscosity the dynamic viscosity deviates from what is commonly regarded as a general law. The reason lies in the fact that with internal viscosity the intramolecular tension contains a contribution depending on x h,t), unlike the other models where it depends on the elastic force only, that is, on x h,t). 

Nanoparticles may be solids, liquids or gases. Examples include nanocrystals, nanoscale liquid droplets, and gas bubbles in nanopores in nanostructured solids. In the case of nanoscale liquids, properties such as viscosity deviate from bulk values as the thickness of the water film decreases below a few nanometers. However, recent results suggest that the viscosity change in low ionic strength aqueous solutions is much less than for non-associated liquids (such as organics) and remains within a factor of 3 of its bulk value in films in the range 0.0 0.4 nm to 3.5 1 nm (Raviv et al. 2001). Although... 

Hochstrasser and his co-workers on both stilbene and diphenyl-butadiene. Their interpretation is based on measurements carried on the "stiff" diphenylbutadienes, where the phenyls are held rigid by saturated chains of 2-4 carbon atoms linked through the 2 positions of aromatic ring to the double band. The apparent energy barriers and the dependence on viscosity deviate from the Kramer s model but are consistent with the modified Kramers-Hubbard model... 

Measurements should be made at 23 0.5 "C. According to ISO 2431 flow cups should only be used for substances exhibiting Newtonian flow. However, they are also often employed for near-Newtonian paints where the flow behavior at the desired viscosity deviates only slightly from Newtonian behavior (e.g., when adjusting the application consistency by dilution). 

Mixture viscosities Includes also viscosity deviations 14400... 

The thermal conductivity and the shear viscosity of ammonia were also predicted with a good accuracy on the basis of the force field by Eckl et al. [97] in the same temperature and pressure range. The predictions of the thermal conductivity and the shear viscosity deviate on average by 3 and 14%, respectively, from the experimental data. 

For the three different viscosities investigated (0.8, 5.6, and 15.0 Pas), the curves of the two highest viscosities almost coincided, indicating a similarity in flow profiles. The curve of the lowest viscosity deviated considerably. This can be explained by the different behavior of this material, due to gravity, as explained in Section VII of Chapter 2. Low viscosities lead to shorter mean residence times, smaller reduced variances and an increased influence of changes in rotational speed. 

XX Viscosity Deviator XZ Viscosity Deviator ZZ Viscosity Deviator Gas Constant... 

Bulk or Artificial Viscosity XX Viscosity Deviator XZ Viscosity Deviator Gas Constant ZZ Viscosity Deviator XX Elastic Stress Deviator XZ Elastic Stress Deviator ZZ Elastic Stress Deviator Temperature "K... 

The excess viscosity (deviation from Arrhenius law) for the mixtures is written as ... 

Clara, R. A. Gomez Marigliano, A. C. Solimo, H. N. Density, viscosity, isothermal (vapour+liquid) equilibrium, excess molar volume, viscosity deviation, and their correlation for chloroform -l- methyl isobutyl ketone binary system. J. Chem. Thermodyn. 2007, 39, 261-267. 

The addition of water in PIL solutions decreases drastically the viscosity of the media compared to the viscosity of pure PILs. For example, the viscosity of pure [HPyr][HS04] is close to 156.3 cP, whereas when mixed with water, the equimolar composition has a viscosity close to 33 cP. Additionally, for high concentrations of PILs (jCil>0.5), anion choice also affects dramatically the solution viscosity [89]. This effect is driven by the fact that the HS04-based PIL is around nine times more viscous than PIL containing the [CF3CO2] anion. For a lower PIL mole fraction, such a difference tends to decrease, since the viscosity of each aqueous solution tends to converge toward the viscosity of pure water. The dependence of the viscosity deviations from ideahty, (n =n (xi Hi+ 2 <12)) as a function of the PIL mole fraction composition, XpiL, expresses the modification of ionic association by the addition of water (7.2) in PILs (7.1). 

Fig. 7.10 Viscosity deviations from ideality, ri", as a function of the PIL mole fraction composition, XpiL for the aqueous mixture [HPyr][HS04] and [HPyrllCFsCOi] ([HPyr] = [Pyrr]). Reproduced from [89] with permission from Elsevier...

Chem. Descrip. Tetramethyl-5-decyne4,7-diol, 2,4,7,9-, blended with proprietary components Ionic Nature Nonionic CAS 126-86-3 EINECS/ELINCS 204-809-1 Uses Substrate wetting agent in water-based coatings, inks, adhesives Features Helps to overcome viscosity deviations in architectural coatings where assoc, thickeners are used... 

A pressure rheometer was built to measure rheological properties of polymers at elevated pressures and temperatures. However the viscosity at high deformation rates decreases more than the predicted theoretical value represented by the Cross-WLF model. This paper studies the role of viscous heating in the resulting viscosity deviations by means of simulation nsing the Radial Functions Method (RFM). 

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