Composite characteristics micrographs

The several A and E values cited apply to the overall reaction, which involves composite nucleation followed by growth. Attempts were made to measure individually the kinetic characteristics of these steps from examination of electron micrographs for salt decomposed (a < 0.2). Such... 

Scanning electron micrography indicates that zeolite crystals are homogeneously distributed in the composites. Micrographs show the characteristic aggregates of octahedral crystals of zeolite X from methods A and C and the cubic crystals of zeolite A from method B. 

SEM micrographs of the wear scars of EPDM gum and PTFE-EPDM composites are shown in Fig. 35. EPDM gum shows a characteristic failure mode caused by... 

Typical polarized optical micrographs of the molten samples were shown in Figure 1. Microscopic analyses were earned out at temperatures in the range 25 - 390 C, and threaded textures, a characteristic optical texture of nematic mesophase, were observed above LCITs over the investigated composition range. The nematic to isotropic transitions were not observed up to 390 C. 

Over the decades that have passed since La Mer s work numerous examples of monodispersed particles of various composition, morphologies and properties, as well as methods for their preparation (not limited to condensational formation), were described in the literature. Extensive studies in this area were carried out by E. Matijevic and T. Sugimoto. Examples of monodisperse systems formed by precipitation from homogeneous solutions include dispersions of uniform particles of simple composition having different morphologies, such as metal halides, sulfides, phosphates, (hydrous) oxides, etc, various composite particles, including particles of internally mixed composition and coated particles. Both crystalline and amorphous materials can be obtained. Electron micrographs of some characteristic examples of monodispersed colloids are shown in Fig. IV-14. 

Figure 7 demonstrates that Equation 3 is strictly applicable only in the very earliest stages of phase separation. The micrographs show simultaneous growth of composition differences and characteristic particle size after 4.4 min... 

In an effective properties model, the porous microstructures of the SOFC electrodes are treated as continua and microstructural properties such as porosity, tortuosity, grain size, and composition are used to calculate the effective transport and reaction parameters for the model. The microstmctural properties are determined by a number of methods, including fabrication data such as composition and mass fractions of the solid species, characteristic features extracted from micrographs such as particle sizes, pore size, and porosity, experimental measurements, and smaller meso- and nanoscale modeling. Effective transport and reaction parameters are calculated from the measured properties of the porous electrodes and used in the governing equations of the ceU-level model. For example, the effective diffusion coefficients of the porous electrodes are typically calculated from the diffusion coefficient of Eq. (26.4), and the porosity ( gas) and tortuosity I of the electrode ... 

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