Anisotropy stress induced

The optical transition moments for vibrational or electronic transitions between defect states have specific orientations with respect to the defect coordinates. The absorption strength of polarized light for each of the differently oriented centers is proportional to the square of the component of the transition moment that is along the polarization direction. Hence, a stress-induced redistribution of the defects among their different orientations will be detected as an anisotropy in the polarized optical absorption. A convenient measure of the anisotropy is the dichroic ratio, defined as... 

Sharma (90) has examined the fracture behavior of aluminum-filled elastomers using the biaxial hollow cylinder test mentioned earlier (Figure 26). Biaxial tension and tension-compression tests showed considerable stress-induced anisotropy, and comparison of fracture data with various failure theories showed no generally applicable criterion at the strain rates and stress ratios studied. Sharma and Lim (91) conducted fracture studies of an unfilled binder material for five uniaxial and biaxial stress fields at four values of stress rate. Fracture behavior was characterized by a failure envelope obtained by plotting the octahedral shear stress against octahedral shear strain at fracture. This material exhibited neo-Hookean behavior in uniaxial tension, but it is highly unlikely that such behavior would carry over into filled systems. 

Ultrasonic Pressure Transducers. Advantage is taken of the fact that pressure influences sound propagation in solids, liquids, and gases, but in different ways. In solids, applied pressure leads to so-called stress-induced anisotropy, In liquids, the effects of pressure are usually small (relative to effects in gases), but the frequency of relaxation peaks can be shifted significantly,... 

Once that the enhancement of the anisotropy due to the nanometric dimensions of the particle has been proven in our samples beyond doubt, the pertinent question is whether we can find the physical origin of this enhancement. A number of possible mechanisms can give rise to this strong variation in anisotropy size effects due to the increasing ratio of surface to bulk atoms, electronic confinement within the cluster leading to 3d band narrowing, surface oxidation, stress induced anisotropy, or even shape anisotropy due to a departure of sphericity. The two latter ones can be readily disregarded. The interatomic Co distance is estimated from the analysis of EXAFS spectra of these clusters. They are shorter than the bulk fee Co and comparable to that found for free Co clusters [11,12], Therefore... 

As the head track width decreases, remanent magnetization of the main pole tip is likely to occur because of stress-induced anisotropy and increased shape anisotropy in the normal direction to the ABS. The field from this remanent magnetization can... 

Figure 1 presents the three basic mechanisms of stress induced permeability change in fractured rock (a) normal closure/opening, (b) shear dilation/contraction and (c) induced anisotropy due to different orientations of fractures and anisotropic stress condition. 

Temporal variation of shear wave splitting parameters as a stress indicator has been employed at several other volcanoes. While most studies concentrate on either stress-induced anisotropy or structurally dominated anisotropy, several studies have found that the dominant mechanism can change between the two (Keats et al. 2011 Johnson and Poland 2013) and that more than one mechanism can be dominant over short distances, potentially creating an apparent temporal change that is actually an artifact of changing earthquake location (Zinke and Zoback 2000). 

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