Elasticity ratio

Parameter k e is termed as the viscosity-to-elasticity ratio here, which labels the relative ratio of viscosity to elasticity. In the typical case of EHL, this value is strong enough to assure it pertinent to omit the elastic effect. But in the typical TFL case, its order of magnitude is close to one and the elasticity must be taken into account. 

Velocity profiles are demonstrated from Figs. 6 and 7. Figure 6 shows the effects of the viscosity-to-elasticity ratio at negative and positive normal stress gradients. Figure 7 shows the effects of various normal stress gradients on velocity profiles at the value of = 0.6. No general conclusions can be drawn... 

Discrepancy of TFL from EHL results from the elasticity of lubricants. The viscosity-to-elasticity ratio is introduced to account for the effects of the elasticity. If the viscosity plays a dominant role, it keeps constant, but if the elasticity prevails, the angle of the director varies linearly consequently the viscosity varies. 

Fig. 6—Velocity profile at various viscosity-to-elasticity ratios.

Modulus of elasticity - Ratio of stress to strain within the elastic range. Same as Young s modulus. 

Steinmann S, Gronski W, Friedrich C (2001) Cocontinuous polymer blends influence of viscosity and elasticity ratios of the constituent polymers on phase inversion. Polymer 42 6619-6629... 

It may be mentioned that the Debye characteristic temperature can be derived from other properties of the element, particularly from the compressibility and Poisson s (elasticity) ratio. Where such data are available it is thus possible to obtain reasonably accurate heat capacities, at moderate and high temperatures, from elasticity measurements. 

PE/PP EPR Processing conditions, melt viscosity and elasticity ratios, and MWD, affect the melt and solid morphology, and hence the performance. Teh et al., 1994... 

The microrheology makes it possible to expect that (i) The drop size is influenced by the following variables viscosity and elasticity ratios, dynamic interfacial tension coefficient, critical capillarity number, composition, flow field type, and flow field intensity (ii) In Newtonian liquid systems subjected to a simple shear field, the drop breaks the easiest when the viscosity ratio falls within the range 0.3 < A- < 1.5, while drops having A- > 3.8 can not be broken in shear (iii) The droplet breakup is easier in elongational flow fields than in shear flow fields the relative efficiency of the elongational field dramatically increases for large values of A, > 1 (iv) Drop deformation and breakup in viscoelastic systems seems to be more difficult than that observed for Newtonian systems (v) When the concentration of the minor phase exceeds a critical value, ( ) >( ) = 0.005, the effect of coalescence must be taken into account (vi) Even when the theoretical predictions of droplet deformation and breakup... 

Density Elasticity Ratio Cohesion Angle Name flcg/m ) E(MPa) v c(MPa) (p(°)... 

Viscosity ratio Elasticity ratio Interfacial tension... 

PP blends with a small amount of LCP are of industrial interest for two reasons (i) to improve processability or (ii) to improve the mechanical performance. The second effect depends on the blend s morphology, i.e., on the orientation of LCP domains. The latter depends on the concentration, viscosity and elasticity ratios, interfacial tension coefficient, fiow type and intensity, total strain, drawdown ratio, etc. Three stages of orientation are (1) drop deformatiOTi, (2) fibrillation of the domains, and (3) stretching of the LCP chains (Champagne et al. 1996). Only the latter provides a reasonable cost-to-performance ratio. Examples of PP/LCP systems are listed in Table 1.53. 

Based on microrheology, it is possible to expect that (i) the drop size is influenced by the following variables viscosity and elasticity ratios, dynamic interfacial tension coefficient, critical capillary number, composition, flow field type, and flow field intensity (ii) in Newtonian liquid systems subjected to a simple shear field, the drop breaks most easily when the viscosity ratio falls within the... 

Flow along the central axis of a converging conical channel was used to investigate the contribution of elasticity on drop using a Roger fluid. Drop deformation decreases with increasing elasticity. For elasticity ratio, h < 0.2, the matrix elasticity has more effect on the drop deformation than drop elasticity. However, for k > 0.2, drop deformation is more affected by drop elasticity Mighri et al. 1997... 

Interfacial instability in a number of coextruded polymer systems has been experimentally correlated with viscosity ratios and elasticity ratios (25), and a simplified rheology review has been given (26). 

Young s modulus (modulus of elasticity) Ratio of engineering stress to engineering strain for relatively small levels of load application. 

FIGURE 2.19. Dependence of elastic ratio K33IK11 on the number of carbon atoms (length of alkyl chain) in the homologues series of... 

As mentioned above, dimer formation considerably affects the elastic ratio KssfKii. For instance, in the mixtures of the fifth and seventh homologues of cyanoderivatives of different chemical classes there exists a noticeable change in Kss/Kn, despite the fact that the length-to-width... 

FIGURE 2.20. Concentration dependence of the elastic ratio Kzz/K on the mixtures of weak and strong polar compounds [47]. Reduced temperatme r = 0.95, weak polar matrix of azoxycompounds corresponds to X = 0. Concentration (X) dependences of the following strong polar compounds are given ... 

The elastic ratio KssfKu could be determined by measuring the relative phase difference in a homeoplanar (hybrid) liquid crystal cell [45]... 

The attempts at optimization of the TVC steepness parameter show that the latter increases for the higher elastic ratios Kzz/Kn and increases for lower values of the dielectric anisotropy Ae/e , while the effect of the optical path difference And and the elastic ratio KZ3IK22 is small [86-93]. It was shown, that the maximum steepness parameter is obtained when And 2A, i.e., near the second Mauguin minimum [88, 90] (4.56). If the director pretilt angle at the boundaries is not equal to zero, the TVC steepness parameter decreases [89, 93]. Reference [90] proposed a phenomenological formula for the evaluation of the steepness parameter pso of the TVC based on the experimental data for the binary mixtures of compounds belonging to twelve structurally and physically different liquid crystal classes... 

No. of the Mauguin minimum m Layer thickness d (pm) Elastic ratio K33/K11 Steepness parameter PlO P50 No. N of maximum addressed lines N(p - pso)... 

The melt elasticity ratio is said to be important for the texture of the mixture and the shape of the immiscible domains. Furthermore, it is to be noted that the relaxation is time-dependent. A stable deformed droplet can only be obtained if the ratio of the characteristic relaxation time ratio of the dispersed and continuous phase is larger than one ... 

The coefficient of thermal endurance for selected materials is shown in Table 4.9. The phenomenally high coefficient of thermal endurance for BN is primarily a result of the high tensile strength to modulus of elasticity ratio compared to other materials. Diamond is also high, primarily because of its high tensile strength, high thermal conductivity, and low TCE. 

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