Growing stress

Sensory sensations. Growing stress, rising affluence, and availability of global foods are driving consumer demands for new and more intense taste sensations. 

The dislocations move and yielding is initiated when the equilibrium is exceeded by the growing stress ty... 

Human DN 0 h—stress of drivers in the traffic jam, 3 h—the growing stress of drivers, the disruption of... 

Polymerization reaction is initiated by the active sites located inside the catalyst pores where ethylene and the alkyl-aluminum cocatalyst penetrate. As the polyolefin chains grow, stress develops inside the catalyst pores and small particles are... 

Under compression or shear most polymers show qualitatively similar behaviour. However, under the application of tensile stress, two different defonnation processes after the yield point are known. Ductile polymers elongate in an irreversible process similar to flow, while brittle systems whiten due the fonnation of microvoids. These voids rapidly grow and lead to sample failure [50, 51]- The reason for these conspicuously different defonnation mechanisms are thought to be related to the local dynamics of the polymer chains and to the entanglement network density. 

Substantial work on the appHcation of fracture mechanics techniques to plastics has occurred siace the 1970s (215—222). This is based on earlier work on inorganic glasses, which showed that failure stress is proportional to the square root of the energy required to create the new surfaces as a crack grows and iaversely with the square root of the crack size (223). For the use of linear elastic fracture mechanics ia plastics, certaia assumptioas must be met (224) (/) the material is linearly elastic (2) the flaws within the material are sharp and (J) plane strain conditions apply ia the crack froat regioa. 

At low temperatures, the surface mobiUty of the atoms is limited and the stmcture grows as tapered crystaUites from a limited number of nuclei. It is not a full density stmcture but contains longitudinal porosity on the order of a few tens of nm width between the tapered crystaUites. It also contains numerous dislocations with a high level of residual stress. Such a stmcture has also been caUed botryoidal and corresponds to Zone 1 in Figures 6 and . 

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