Accommodation mechanisms

These glassy phases may act as a lubricant for grain boundary sliding. In this case, the accommodation mechanism is the viscous motion of these secondary phases. 

Duclos, R., Crampon, J., and Carry, C., Grain-boundary sliding and accommodation mechanism during creep of yttria-stabilized zirconia , Phil. Mag. Lett., 2002, 82, 529-33. 

Copeland P, Harrison TM, Kidd WSF, Ronghua X, Yuquan Z (1987) Rapid early Miocene acceleration of uplift in the Gandese Belt, Xizang (southern Tibet), and its bearing on accommodation mechanisms of the India-Asia collision. Earth Planet Sci Lett 86 240-252 Culler TS, Becker TA, Muller RA, Reime PR (2000) Lunar impact history from Ar-40/Ar-39 dating of glass spherales. Science 287 1785-1788... 

Depending on which of the above factors dominates during deformation, the accommodation mechanism may be regarded as viscous flow, solution-precipitation, or cavitation creep. In general, cavitation creep can be discarded as an accommodation mechanism for superplasticity, as the strain-to-failure afforded by this mechanism is rather small. Therefore, only viscous flow and solution-precipitation mechanisms are important. Obviously, too, whether these mechanisms apply depends on the presence or absence of a liquid phase. Solution-precipitation requires a liquid phase to envelop the grains, while viscous flow is facilitated by the fast diffusion path of the liquid, although it may also occur in a dry polycrystal via diffusional creep. 

Fig. 3 Energy accommodation mechanisms of ablative thermal protections systems [69]...

Sakaguchi, S., Morita, A. Mass accommodation mechanism of water through mmiolayer fihns at water/vapor interface. J. Chem. Phys. 137(064701), 9 (2012). doi 10.1063/1.4740240 Salgado-Munoz, M.S., Rossi, M.J. Heterogeneous reactions of HNO3 with flame soot generated under different combustion conditions. Reaction mechanism and kinetics. Phys. Chem. Chem. 

Based on these results, the transition from the abrasive wear to the low-wear regime has been explained in terms of velocity accommodation mechanisms in the interface film. The most important phenomenon is a complex polyphasic tri-bochemical reaction responsible for the formation of a solid transition-metal phosphate glass material as an adherent thin film. This acts as a protective layer against wear due to its superplastic behavior when it is formed in the contact... 

Figure 7.8 Designs with a temperature approach or small temperature cross can be accommodated in a single 1-2 shell, whereas designs with a large temperature cross become infeasible. (From Ahmad, Linnhoff, and Smith, Trans. ASME, J. Heat Transfer, 110 304, 1988 reproduced by permission of the American Society of Mechanical Engineers.)...

In sorjDtion experiments, the weight of sorbed molecules scales as tire square root of tire time, K4 t) ai t if diffusion obeys Pick s second law. Such behaviour is called case I diffusion. For some polymer/penetrant systems, M(t) is proportional to t. This situation is named case II diffusion [, ]. In tliese systems, sorjDtion strongly changes tire mechanical properties of tire polymers and a sharjD front of penetrant advances in tire polymer at a constant speed (figure C2.1.18). Intennediate behaviours between case I and case II have also been found. The occurrence of one mode, or tire otlier, is related to tire time tire polymer matrix needs to accommodate tire stmctural changes induced by tire progression of tire penetrant. 

There is an experimental variation in which an W-phenacylpyridinium salt is heated with an aniline[4]. This reaction can also be readily accommodated to the mechanism involving an imine intermediate. There are a few examples of use of other types of a-halokctoncs[5,6] but most of the synthetic applications have been to 2-arylindoles. 

One important experimental fact is that the rate of reaction of alcohols with hydro gen halides increases m the order methyl < primary < secondary < tertiary This reac tivity order parallels the carbocation stability order and is readily accommodated by the mechanism we have outlined... 

The regioselectivity of elimination is accommodated m the E2 mechanism by noting that a partial double bond develops at the transition state Because alkyl groups... 

All these facts—the observation of second order kinetics nucleophilic attack at the carbonyl group and the involvement of a tetrahedral intermediate—are accommodated by the reaction mechanism shown m Figure 20 5 Like the acid catalyzed mechanism it has two distinct stages namely formation of the tetrahedral intermediate and its subsequent dissociation All the steps are reversible except the last one The equilibrium constant for proton abstraction from the carboxylic acid by hydroxide is so large that step 4 is for all intents and purposes irreversible and this makes the overall reaction irreversible... 

The flame-space walls are stainless steel and are water cooled. No mechanical coke scraper is required. A water quench cools the cracked gas stream rapidly at the poiat of maximum acetyleae and this is followed by a secondary water quench. The primary quench poiat can be adjusted for variation ia throughput, to accommodate the depeadeace of acetyleae yield oa resideace time ia the flame space. 

The morphological variance appears more important with chrysotile than with amphiboles. The intrinsic stmcture of chrysotile, its higher flexibiUty, and interfibnl adhesion (10) allow a variety of intermediate shapes when fiber aggregates are subjected to mechanical shear. Amphibole fibers are generally more britde and accommodate less morphological deformation during mechanical treatment. 

Elsewhere, large block carbons are utilized as wall material, generally with thicknesses in the range of 1.5—2.5 m. However, the single-thickness blocks have a tendency to crack and spall because of high mechanical and thermal stress and lack of expansion provisions. To combat this problem, various exotic carbons have been developed to resist hot metal penetration and increase thermal conductivities, but it should be noted that these measures do not solve the cause of the cracking, which is a lack of provisions to accommodate differential expansion. 

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