Interactions grains

Overall, the results from the cathode-only KMC simulations [118-120] were found to be qualitatively consistent with experimental trends, with a great deal of the atomistic-level details preserved. However, in order to improve the results, and approach quantitative agreement with experiments, additional features must be incorporated, such as the anode-side reactions, correlation of the ion-vacancy and vacancy-vacancy interactions, grain boundaries, and explicit structural treatment of the anode and cathode. In order to incorporate some of these necessary features, two KMC-based SOFC simulation studies have recently emerged [126,127] along with some close experimental collaboration [128], In all of these more recent studies, a complete SOFC model (anode+cathode) was assembled. 

Mature systems have good thickness control and repeatability Rapid means for studying film-substrate interaction, grain growth behavior, effect of dopants, etc. 

Figure B3.6.3. Sketch of the coarse-grained description of a binary blend in contact with a wall, (a) Composition profile at the wall, (b) Effective interaction g(l) between the interface and the wall. The different potentials correspond to complete wettmg, a first-order wetting transition and the non-wet state (from above to below). In case of a second-order transition there is no double-well structure close to the transition, but g(l) exhibits a single minimum which moves to larger distances as the wetting transition temperature is approached from below, (c) Temperature dependence of the thickness / of the enriclnnent layer at the wall. The jump of the layer thickness indicates a first-order wetting transition. In the case of a conthuious transition the layer thickness would diverge continuously upon approaching from below.

A fiirther step in coarse graining is accomplished by representing the amphiphiles not as chain molecules but as single site/bond entities on a lattice. The characteristic architecture of the amphiphile—the hydrophilic head and hydrophobic tail—is lost in this representation. Instead, the interaction between the different lattice sites, which represent the oil, the water and the amphiphile, have to be carefiilly constmcted in order to bring about the amphiphilic behaviour. 

Kingery WD and Francois B 1965 The sintering of crystaiiine oxides, i. interactions between grains boundaries and pores Sintering and Related Phenomena ed G C Kuczynski, N A Hooton and C F Gibbon (New York Gordon and Breach) pp 471-98... 

Chemical Inhomogenities or Compositional Separation. Compositional separation at the grain boundaries influences the magnetic interactions of the individual grains. Deposition parameters such as temperature, substrate material, and the use of a seed layer play an important role. 

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