Softening description

It is instructive to describe elastic-plastic responses in terms of idealized behaviors. Generally, elastic-deformation models describe the solid as either linearly or nonlinearly elastic. The plastic deformation material models describe rate-independent behaviors in terms of either ideal plasticity, strainhardening plasticity, strain-softening plasticity, or as stress-history dependent, e.g. the Bauschinger effect [64J01, 91S01]. Rate-dependent descriptions are more physically realistic and are the basis for viscoplastic models. The degree of flexibility afforded elastic-plastic model development has typically led to descriptions of materials response that contain more adjustable parameters than can be independently verified. 

In particular it can be shown that the dynamic flocculation model of stress softening and hysteresis fulfils a plausibility criterion, important, e.g., for finite element (FE) apphcations. Accordingly, any deformation mode can be predicted based solely on uniaxial stress-strain measurements, which can be carried out relatively easily. From the simulations of stress-strain cycles at medium and large strain it can be concluded that the model of cluster breakdown and reaggregation for prestrained samples represents a fundamental micromechanical basis for the description of nonlinear viscoelasticity of filler-reinforced rubbers. Thereby, the mechanisms of energy storage and dissipation are traced back to the elastic response of tender but fragile filler clusters [24]. 

From the above description it will be appreciated that the efficiency of release of nutrients from ingested plant material is dependent upon the ease with which the digestive enzymes can penetrate the cell wall to release the nutrients so that they can diffuse out of the structure to be absorbed. Thus tissue maturity, cooking, macerating, mastication and mode of tissue failure, all of which control particle size, cell wall softening or cell disruption, are key features which regulate nutrient release. 

It is difficult to define unequivocally the quality of fabric handle or softness/firmness differences, since this involves many factors. It is often linked with lubrication, especially as similar products are often used for softening and lubrication. Whilst experienced assessors can be quite remarkable in the extent to which they can grade and assess softeners simply by means of a highly developed tactile sense, more objective methods are clearly desirable for scientific investigations. Since many factors combine in producing an overall sense of softness, it is not surprising that objective determination of softness involves more than one parameter of measurement. The details of assessment are outside the scope of this chapter, but descriptions and discussions are available elsewhere [478-481]. Suffice it to say here that the Kawabata system has acquired considerable importance in quantifying various aspects of fabric handle. 

Since there is no good physical framework in which the measured hardness versus temperature data can be discussed, descriptions of it are mostly empirical in the opinion of the present author. Partial exceptions are the elemental semiconductors (Sn, Ge, Si, SIC, and C). At temperatures above their Debye temperatures, they soften and the behavior can be described, in part, in terms of thermal activation. The reason is that the chemical bonding is atomically localized in these cases so that localized kinks form along dislocation lines. These kinks are quasi-particles and are affected by local atomic vibrations. 

Some of the early descriptions of the effect of MOX on red wine included an interesting cycling effect where certain organoleptic aspects of wine quality appear to get worse before the continued application of MOX leads to the desired improvements (Dykes and Kilmartin, 2007 Parish et al., 2000 Vinovation, 2009). In the first "structuring" phase (for several days to weeks), the wine tannins are said to become more aggressive and the varietal aromas decrease, after which the tannins soften and... 

Description and Properties. — Ammoniac is found in tears and drops, sometimes distinct, but more generally in agglutinated masses. Externally the tears ore yellow, with a tinge of brown, with a waxy lustre internally they are whits or cream-colored, and opaque. It is moderately hard, and at ordinary temperatures brittle, but softens like wax with the heat of the hood. It hoe a faint and somewhat unpleasant, but very peculiar odor, best detected by subjecting it te heat j its teste is bitter and nauseous. 

Therefore if quadratic coupling can be neglected and A3 > 0 the curvature for the 3Z2 — r2 electronic state is softened, while that for the x2 — y2 state increases. Of course the same effect is produced if A3 is negligible and Vq > 0. The present description can be applied to a good extent to the case of substitutional d9 ions in cubic lattices with octahedral coordination. Under a Qe distortion there are two electronic states in D4h in Blg the hole is in blg ( x2 — v2 ), while in Alg it is placed in the al ( 3z2 — r2) orbital. Bearing in mind this fact the E Blg Qe) curve for d9 ions looks similar to E(3z2 — r2 Qe) for d7 ions. 

So far, we have considered the elasticity of filler networks in elastomers and its reinforcing action at small strain amplitudes, where no fracture of filler-filler bonds appears. With increasing strain, a successive breakdown of the filler network takes place and the elastic modulus decreases rapidly if a critical strain amplitude is exceeded (Fig. 42). For a theoretical description of this behavior, the ultimate properties and fracture mechanics of CCA-filler clusters in elastomers have to be evaluated. This will be a basic tool for a quantitative understanding of stress softening phenomena and the role of fillers in internal friction of reinforced rubbers. 

Within the industrial applications of HP, besides the antimicrobial actions they present, they have been used in some countries for soy protein hydrolysis, for freezing, to soften meat, for discoloration of hemoglobin, as by-products in the meat industry, to deodorize proteins, and to make soluble or modify fish proteins (Cheftel, 1995 Palou et al., 2002 Ting and Marshall, 2002a,b). Some examples of the interaction of HP with biological structures of foods are presented in the next section with a major description on milk and its products. 

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