Dynamic yielding

Shock-wave data have seen most applications in the measurement of density at high pressure. Other properties of compressed condensed materials whose measurements are discussed in this chapter include sound speed and temperature. Review articles by Grady (1977), Yakushev (1978), Davison and Graham (1979), Murri et al. (1974), Al tshuler (1965), and Miller and Ahrens (1991) summarize experimental techniques for measuring dynamic yielding. 

Shock-Induced Dynamic Yielding and Phase Transitions... 

J.W. Taylor, Dislocation Dynamics and Dynamic Yielding, J. Appl. Phys. 36, 3146-3150(1965). 

Since MPC dynamics yields the hydrodynamic equations on long distance and time scales, it provides a mesoscopic simulation algorithm for investigation of fluid flow that complements other mesoscopic methods. Since it is a particle-based scheme it incorporates fluctuations, which are essential in many applications. For macroscopic fluid flow averaging is required to obtain the deterministic flow fields. In spite of the additional averaging that is required the method has the advantage that it is numerically stable, does not suffer from lattice artifacts in the structure of the Navier-Stokes equations, and boundary conditions are easily implemented. 

If nonreactive MPC collisions maintain an instantaneous Poissonian distribution of particles in the cells, it is easy to verify that reactive MPC dynamics yields the reaction-diffusion equation,... 

Here the fitting parameters are the slope of the line (the plastic viscosity, rip) and the Bingham or dynamic yield stress (the intercept, constitutive equations will be introduced later in this volume as appropriate. 

It is important when using the term yield stress to distinguish between an extrapolated value, sometimes called the dynamic yield stress and a true or static yield stress . The latter can only be observed for plastic solids whilst the former is readily obtained with pseudoplastic liquids. In practical terms this can be critical in evaluating the performance of a material. 

Yield. The Rb-82 content of 50 ml of eluate, decay corrected to end of elution, collected at 50 ml/min is measured in a Capintec CRC-17 dose calibrator using the potentiometer setting recommended by the manufacturer for Rb-82. While this datum is not as significant as the dynamic yield information obtained from measurement of elution profiles, it is valuable in preliminary development work and in monitoring the performance of a given unit through an extended use period. 

Construction of the Dynamic Internal Yield Locus. The dynamic yield locus represents the steady state deformation, as opposed to the static yield locus which represents the incipient failure. The dynamic yield locus is constructed by plotting on a (a, t) plane the principal Mohr circles obtained for various consolidation stresses. The dynamic yield locus will be the curve or straight line tangent to all circles, as shown in Figure 17. The dynamic angle of internal friction S and cohesion C are independent of the consolidation stress. S and Q are obtained as the slope and the intercept at er=0 of the dynamic yield locus of the powder. 

A time-resolved ion yield study of the adenine excited-state dynamics yielded an excited-state lifetime of 1 ps and seemed to support the model of internal conversion via the nn state along a coordinate involving six-membered ring puckering [187]. In order to determine the global importance of the tict channel, a comparison of the primary photophysics of adenine with 9-methyl adenine will be useful, as the latter lacks a tict channel at the excitation energies of concern here. The first study of this type revealed no apparent changes in excited-state lifetime upon methylation at the N9 position [188] a lifetime of 1 ps was observed for both adenine and 9-methyl adenine. This was interpreted as evidence that the tict is not involved in adenine electronic relaxation. 

The dynamic yield stress (extrapolated to zero shear rates, Figure 8.15) becomes greater with stronger field, indicating the increase of attractive forces between the polarized particles with applied electric field. This phenomenon is attributed to columnar or fibrillar structure formed by the particles as a response to electrostatic interactions induced by electric field. The stronger the field, the larger shear rate is needed to destroy the structure. 

Beside the strength of electric field, the dynamic yield stress significantly depends on the amount of MWCNT in the composite particles. As can be seen in Figure 8.15, for different field strength the yield stress goes up with rising concentration in different ways. While for 1 and 2 kV/mm, it continuously increases with nanotubes content, at 3 kV/mm a saturation effect can be observed. The presence of MWCNT enhances the conductivity of the composite particles and thus influences their ability to be polarized. If the conductivity of the particles is above a certain limit, the current density in the... 

If an organization can hx its position on the life cycle curve (S curve), and it has a sense of the slope of the curve, it has an excellent mechanism for determining where its technology is headed, and it can also determine the relative rapidity of that movement. Understanding this dynamic yields unique insights on how to direct product/service development and R D processes, as well as how to proactively align core competencies with new technology imperatives. 

Figure 3-12 Illustration of Static and Dynamic Yield Stress (Keentok, 1982).

The structure of the food sample would be disturbed considerably during the determination of Apminj so that the measured yield stress would be closer to the dynamic yield stress than the static yield stress (Figure 3-10). In contrast, in the vane method for determination of yield stress both the static and dynamic yield stresses can be determined. 

Figure 4-26 Static (-S) and Dynamic (-D) Yield Stress Values of Cross-Linked Waxy Maize (CWM), Tapioca, and Amioca 5% (w/w) Starch Dispersions at Different Shear Rates. Filled symbols are values of static yield stress (aps) open symbols are values of dynamic yield stress (oqj).

Klingenberg et al. (1991a) find in their simulations a dependence of the dynamic yield stress on particle volume fraction 0 that is in qualitative agreement with experiment (see Fig. 8-7). Note that in both experiments and simulation, Oy is roughly linear in 0 for 0 0.30. 

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