MATERIALS AND MICROSTRUCTURES

Strain hardening effect, 20 224 Straining efficiency, 77 340 Strain rate, 73 473 Strain recovery rate (Rr), in testing shape-memory polymers, 22 361 Strain sensors, 77 150, 151-152 Strain tensor, for noncentrosymmetry pont group crystals, 77 93-94 Strain versus time curve factors affecting, 73 473 material and microstructure effect on, 73 473-474... 

Hence, catalysis related challenges for SOFC cathode are the development of cathode specifications, i.e., material and microstructure, having high catalytic activity for oxygen reduction at 600 °C, high electron and ion conductivity, and a low sensitivity for poisoning by volatile Cr species. Again, as for the anode, cost and compatibility related requirements have to be considered. 

A. J. Bard and 11 co-authors. The Electrode/Electrolyte Interface - A Status Report, J. Phys. Chem. 97 (1993) 7147. (Review characterization, reactions, chemical materials and microstructure, 346 references.)... 

Although the above mentioned points will improve our understanding of the interphase, there is already considerable experimental evidence in the literature [3-12] to support the idea that proper arrangement of material and microstructure within an interphase zone will, through a unique synergism, result in enhanced composite properties. 

In continuum-scale electrochemistry, the materials and microstructure of the SOFC tri-layer are embedded in the parameters of the polarization losses. The electrochemistry of the SOFC is inherently dependent on the SOFC microstructure, including the surface area available for the electrochemical reactions, the porosity, tortuosity, and permeability of the porous media, and the material properties of the tri-layer. All these properties affect the rate of reactions in the electrodes and thus the overall voltage produced by the SOFC. Although continuum-scale electrochemistry does not resolve the explicit electrochemical reactions, they are able to accurately model the performance of the SOFC when using experimental data to estimate the parameters of the electrochemistry model. Often the parameters of the continuum-scale electrochemistry model, such as the pre-exponential factors, and activation energies and polarizations are used to fit the continuum-scale electrochemistry to experimental /-V curves. 

Activation-related losses. These stem from the activation energy of the electrochemical reactions at the electrodes. These losses depend on the reactions at hand, the electro-catalyst material and microstructure, reactant activities (and hence utilization), and weakly on current density. 

Initial cell voltage drop due to sulfur contamination is temperature dependent and decrease with increasing temperature [24, 54], The extent and nature of cell degradation is dependent on applied ceU materials and microstructural characteristics and thus the phenomenon of degradation cannot be generalized. It is assumed that any kind of sulfur compound has to be removed to a level <1 ppm to ensure long-term performance of the SOFC. 

The variety of porous membranes, in terms of both materials and microstructures, makes them popular in different chemical reaction processes. They are applied mostly in a tubular configuration. However, the hollow fiber represents a trend for future development due to its remarkably high area/volume ratio. Table 2.5 summarizes the conventional inorganic porous membranes used in membrane reactors. 

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