Instability mechanism

The pressure waves when reflected from the top wall interact with the flame again and cause a destabilizing effect on the flame front. The flame is accelerated toward a denser medium and the growth of the perturbations thus turbulizes the flame front via Rayleigh-Markstein instability mechanism. 

MJ Powell, C van Berkel, and JR Hughes, Time and temperature dependence of instability mechanisms in amorphous silicon thin-film transistors, Appl. Phys. Lett., 54 1323-1325, 1989. 

There is some evidence that isolated drops may shake themselves apart if shape oscillations become sufficiently violent (L7). It has been suggested (El, Gil, H22) that breakup occurs when the exciting frequency of eddy shedding matches the natural frequency of the drop. However, other workers (S7) have found that oscillations give way to random wobbling before breakup occurs. While it is possible that resonance may produce breakup in isolated cases, this mechanism appears to be less important than the Taylor instability mechanism described above. 

Proteins, peptides, and other polymeric macromolecules display varying degrees of chemical and physical stability. The degree of stability of these macromolecules influence the way they are manufactured, distributed, and administered. Chemical stability refers to how readily the molecule can undergo chemical reactions that modify specific amino-acid residues, the building blocks of the proteins and peptides. Chemical instability mechanisms of proteins and peptides include hydrolysis, deamidation, racemization, beta-elimination, disulfide exchange, and oxidation. Physical stability refers to how readily the molecule loses its tertiary and/or sec-... 

The following sections discuss the various instability mechanisms that result in the breakdown of emulsions. Because most of these instability mechanisms are driven by droplet-droplet interactions that occur on the colloidal level, the physical bases of colloidal interactions should be understood as well. Such a detailed discussion is, however, beyond the scope of this unit and interested readers are... 

Creaming or sedimentation. Creaming or sedimentation is one of the principal instability mechanisms seen in emulsions. Emulsion... 

Dreher, T.M. and Stevens, G.W. (1998) Instability mechanisms of supported liquid membranes. Separation Science and Technology, 33, 835. 

J.-M. Samaniego, B. Yip, T. Poinsot, and S. Candel. Low-frequency combustion instability mechanism in a side-dump combustor. Combust. Flame, 94(4) 363-381, 1993. 

Pearson CE, Nichol Edamura K, Cleary JD (2005) Repeat instability mechanisms of dynamic mutations. Nature Rev Genet 6 729-742... 

Snap off by the instability mechanism may occur in the following way. A bubble in an angular constriction such as a square channel will flatten against the walls as shown in Figure 2. The radius of the circular arcs in the corners for a static bubble is about one half of the tube half width. At low liquid flow rates, a bubble trapped behind a constriction has this nonaxisymmetric shape. As liquid flow rate increases, the bubble moves farther into the constriction and the fraction of cross sectional area open to liquid flow at the front of the bubble increases until the thread becomes axisymmetric at some point near the bubble front. 

The essential physical ideas apparently were first known to Zel dovich. The instability mechanisms can be explained by reference to Figure 9.9, where the arrows indicate directions of net fluxes of heat and species. A key element in the explanation is the fact that for large values of the Zel dovich number, the burning velocity depends mainly on the local flame temperature. This intuitively clear result is not entirely obvious from the formulation of Section 9.5.1 but may be motivated from it by employing RudY /d = as a rough approximation to equation (95) in the... 

Fig. 3a—d. Schematic drawing of craze tip advance by the meniscus instability mechanism. 

Craze growth occurs in a lateral direction by advance of a thin finger-like craze tip by the meniscus instability mechanism. Crazes increase in thickness by a surface drawing mechanism in which more polymer is drawn into the craze fibrils at essentially constant extension ratio X from the craze-bulk polymer interface. 

For completeness DiCorleto and Cohen also examined the effect of aging on craze growth in low volume fraction PB diblocks of spherical morphology which craze according to the meniscus instability mechanism As expected from the work of Kefalas and Argon on homopolystyrene, aging had also no measurable effect on craze velocities in this case as well. 

Furthermore, massive stars are supposedly becoming unstable when they approach or penetrate the so called Humphreys-Davidson limit in the HR diagram (Humphreys Davison 1994). We have seen above that, whichever instability mechanism causes the... 

Protein instability mechanisms have been reviewed by several investigators.3-13 Chemical reactions such as oxidation, deamidation, proteolysis, racemization, isomerization, disulfide exchange, photolysis, and others will give rise to chemical instability. It is critical that when this happens, the denaturation mechanisms must be identified in order to select appropriate stabilizing excipients. These chemical excipients may be in the form of amino acids, surfactants, polyhydric alcohols, antioxidants, phospholipids, chelating agents, and others. 

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