Shearing sponge

Figure 8-26 Effect of Sample Weight on Maximum Force Registered with the Shear Press and Using the 10-Blade Standard Cell. (1) White bread and sponge cake, (2) raw apples and cooked white beans, (3) canned beets and peas and frozen peas. Source From A.S. Szczesniak, Instrumental Methods of Texture Measurements, in Texture Measurement of Foods, A. Kramer and A.S. Szczesniak, eds., 1973, D. Reidel Publishing Co.

The reduction occurs by direct oxygen removal from the solid oxides (solid-state diffusion). The basic underlying mechanism is not known (diffusion of O, OH, H2O) and is likely to vary for different for different phase transitions. On the final reduction the metal remains pseudomorphous to the starting oxide, forming a polycrystalline metal sponge. Solid-state reactions are characteristic for low reduction temperatures (<750 °C) and the early WO3 - WO2 9 transition ( crystallographic shear transition). 

When elastic materials (e.g., sponge or spring) are deformed through a small displacement, they tend to return to their original configuration. If a shear stress is applied to an ideal solid, then for a small displacement, Hooke s law is valid ... 

With the increase of the concentration of PPESK in the casting solution, the viscosity strongly increases and becomes shear-rate dependent. Then the morphology of the hollow fiber membranes changes from a finger-like structure to sponge-like structure. 

Note that rheochaos has also been observed in solutions of mixed anionic-zwitterionic surfactants [220] and in other systems including shear-thickening wormlike micelles [239], lamellar, onion, and sponge surfactant phases [156,240-243] and dense colloidal suspensions [244]. 

We usually assume that elasticity (how stress is related to strain) is linear. The assumption is that strains are small so that stresses are linearly related to strains (Hooke s law). We then think of the crystal as a continuum (a structureless sponge ) with two independent elastic constants (for example, p, the shear modulus, and v Poisson s ratio At the core of the dislocation, the strains are too large for this assumption to be valid so we exclude this region from our calculation and replace it by a fudge factor involving r, the core radius (not ideal because it assumes nothing varies across the core and we do not know what is). One consequence of linear elasticity is that when... 

The effect of shear on the L3 phase in the cetylpyridinium chloride/hexanol/(water+NaCl) system with a significant amount of added dextrose has been examined. Additions of of dextrose slow down the diffusional process discussed above. At low shear rate, the sponge phase structure is retained but starting at a shear rate above 500 s, shear thinning reveals the occurrence of a transition to a lamellar phase. Unfortu-... 

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