Stacking deformed

Fig. 11.43 The compressive force versus displacement of stacked PS and LLDPE cylinders at 25°C. Note that initially the stack deformation force tracks that of the more deformable LLDPE, before, at 3 mm, beginning to deform the PS cylinder. [Reprinted by permission from B. Qian, D. B. Todd, and C. G. Gogos, Plastic Energy Dissipation and Its Role on Heating/melting of Single-component Polymers and Multi-component Polymer Blends, Adv. Polym. Technol., 22, 85 (2003).]...

The lamellar reflections in small-angle scattering patterns from polymer fibers are often spread onto a curve symmetrical about the fiber axis. These are usually referred to as two-or four-point patterns, the latter sometimes resembling the butterfly pattern frequently found in light scattering. We recently showed that these 2-D patterns could be best analyzed if we describe die intensity distribution in elliptical coordinates because the intensity maxima of the lamellar reflections from oriented polymers fall on an elliptical curve. We now present new analysis to support this assertion. We will also discuss die physical basis for some of the features in the SAXS pattern in terms of misorientation of the lamellar stacks, deformation of the lamellae, and possible correlation between the lamellar spacing and the orientation of the lamellae. 

A Hquid is a material that continues to deform as long as it is subjected to a tensile and/or shear stress. The latter is a force appHed tangentially to the material. In a Hquid, shear stress produces a sliding of one infinitesimal layer over another, resulting in a stack-of-cards type of flow (Fig. 1). 

M. Bram et al., Deformation Behavior and Leakage Tests of Alternate Sealing Materials for SOFC Stacks, Journal of Power Sources, 138, pp. 111-119 (2004). 

The major problems with Ni-based anodes and NiO cathodes are structural stability and NiO dissolution, respectively (9). Sintering and mechanical deformation of the porous Ni-based anode under compressive load lead to severe performance decay by redistribution of electrolyte in a MCFC stack. The dissolution of NiO in molten carbonate electrolyte became evident when thin electrolyte structures were used. Despite the low solubility of NiO in carbonate electrolytes ( 10 ppm), Ni ions diffuse in the electrolyte towards the anode, and metallic Ni can precipitate in regions where a H2 reducing environment is encountered. The precipitation of Ni provides a sink for Ni ions, and thus promotes the diffusion of dissolved Ni from the cathode. This phenomenon... 

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