Bulk restructuring

Laboratory simulation of catalyst aging in different atmospheres confirmed critical role of oxidizing atmosphere in intensive sintering (Figure 3) and bulk restructuring, being similar at higher temperatures to that in reactor deactivated samples. 

Here, two conclusions are important from this mechanism derived from metallurgical samples of magnetite/wiistite synthetic mixtures. First, the elemental iron is essential to reduce magnetite with hydrogen gas at low temperature. This elemental iron is produced from thermal decomposition of the wiistite mixture in the precursor. Stability and bulk distribution of the wiistite determine the abundance of reaction interfaces in the polycrystalline solid. The grain structure and porosity of the final catalyst is mainly predetermined by the disposition of these reaction centers representing the nuclei of the iron metal crystallines. Second, the reaction involves movement of all iron ions and allows a complete bulk restructuring of the solid at low temperature. The topochemistry of the reduction process will determine... 

The reaction involves movement of all iron ions and allows a complete bulk restructuring of the solid at low temperatures. The topochemistry of the reduction process determines the texture of the resulting ion. The grain structure of the precursor oxide which is essential for a finite reactivity of the bulk oxide mixture is one of the factors controlling the reduction kinetics. 

The North American Electric Reliability Council (NERC), established in 1968, and its associated ten regional councils have been reliability monitors of the electric bulk power system. Their emphasis on compliance with reliability standards through peer pressure was effective in the past. NERC and the councils, with oversight from FERC, are engaged in a complete restructuring of the reliability organizations. This move will ultimately involve a mo V c from peer pressure to mandatoi y compliance. 

Part A, dealing with the Fundamentals of Quantitative Chemical Analysis, has been extended to incorporate sections of basic theory which were originally spread around the body of the text. This has enabled a more logical development of theoretical concepts to be possible. Part B, concerned with errors, statistics, and sampling, has been extensively rewritten to cover modern approaches to sampling as well as the attendant difficulties in obtaining representative samples from bulk materials. The statistics has been restructured to provide a logical, stepwise approach to a subject which many people find difficult. 

Nagy et al. (1999) SEM, ISS Ag-O Restructuring during bulk dissolution + + + Methanol oxidation... 

As has been pointed out recently [10], bulk defects play a major role in a variety of surface phenomena where annealing to high temperature is necessary, e.g. during the encapsulation of Pt [11-13], in bulk-assisted re-oxidation [14,15], in restructuring and reconstruction processes [9,16], and in gas adsorption [17]. The relationship between crystal color, conductivity, bulk defects as characterized by EPR measurements, and surface structure of rutile (110) has been investigated systematically by Li et al. [10]. 

The application of STM to the studies of adsorption and surface reactions in the last two decades has revealed important aspects of the dynamic nature of catalytic metal surfaces. In addition to a local restructuring of metal surfaces with respect to their bulk atomic structure upon adsorption (e.g. the flexible surface), mass transport of... 

---