Pinning mechanisms

The peak in J,(d) at 6= 90° corresponding to the configuration where the magnetic field is parallel to the ab planes can be explained by the following pinning mechanism which is characteristic for the layered oxide. The weakly... 

The crack-pinning mechanism is not very efficient with low-modulus particles such as rubbers. But with stiff thermoplastics (Sec. 13.4), or with high-modulus particles such as inorganic fillers, this mechanism may have an important contribution. 

Figure 13.4 Scheme of the crack-pinning mechanism dp, interparticle distance. 

Understanding of vortex pinning mechanisms will steadily develop and with it the technology of optimising compositions and structures of materials for trapped field magnets, particularly the melt-textured, large grain varieties. 

The exponent m cannot be regarded as a fitting parameter but depends on the symmetry of the system. In most cases, m = 3/2 [16, 140, 158, 166, 167, 174, 175], but m = 2 for highly symmetric systems, such as aligned Stoner-Wohlfarth particles. In particular, the m = 3/2 law is realized for misaligned Stoner-Wohlfarth particles and for most domain-wall pinning mechanisms [5], Experimental values of m tend to vary between 1.5 to 2 [136, 158]. Linear laws, where m = 1, are sometimes used in simplified models, but so far it hasn t been possible to derive them from physically reasonable energy landscapes [5, 16, 176]. The same is true for dependences such as /H- l/H0 [177], where series expansion yields an m = 1 power law. 

Figure 8.44. Crack front propagation slowed down by a pinning mechanism. [Adapted, by permission, from Azimi H R, Pearson R A, Hertzberg R W, J. Appl. Polym. Sci., 58, No.2, 1995,449-63.]...

Figure 8.45 shows experimental data from a different source which confirms the pinning mechanism. Much... 

Figure 8.46 shows the effect of crack advancement on integrity of filler particle. The advancing crack can be delayed by the pinning mechanism if stress is lower than adhesion and filler particle cohesion. If stress is higher than particle cohesion then particles may break. The... 

Translations-Translations Consider the centering pin mechanism in Fig. 2, consisting of a base, a block, and a pin. The upper plane of the base is represented with a magnified bow defect, to which local coordinate frame OpE is associated. The goal is to model the effects of this small geometrical defect on the FR (the pin s axis), to which coordinate frame OpR is also associated. 

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