Structure and texture

The aim of this study is to determine the structure and texture of the initial sample and the temperature and strain rate parameters, at which the superplastic deformation in AlZn78, AlZn76Cu2 and AlZn78 Mg0.02 alloys is the most likely to occur. 

For many reactions in the subsequent sections, the product of dehydration constitutes the reactant in a decomposition. Account must be taken of the changes in structure and texture which accompany or follow withdrawal of water from the lattice (perhaps in several steps) in considering the kinetics of subsequent decompositions or interactions of the anhydrous solid. 

Dimerization of unsaturated fatty acids, to. so-called dimer acids, is widely practised in industry, where acid-treated clays are invariably used as a catalyst. In the case of oleic acid the major products are dimers, trimers, and isosteric acid. Koster et al. (1998) have investigated the relative importance of the various acid sites as well as structural and textural parameters of montmorrilonite. The interlamellar space dominates the oleic acid dimerization and the active site is the tetrahedrol substitution site. 

Finally, it can be envisaged that the future development of novel bio-nanohybrids will lead to new improved properties and multifunctionality derived from the synergistic combination of nanosized inorganic solids, with different structural and textural features, with molecular or even highly organized species of biological origin that are extraordinarily abundant in Nature. 

Structural and textural characterisation of pure SBA-15 and hybrid GFP/SBA-15 Pure SBA-15 and GFP/SBA-15 hybrid were characterised by X-ray powder diffraction, HRTEM and volumetric analysis. Calcined SBA-15 (Fig. 1, curve A) show the typical XRD pattern of an ordered hexagonal network of mesopores with (10), (11) and (20) reflections. The presence of well resolved (11) and (20) peaks indicate that the calcined material used for the preparation of the hybrid materials have a long-range order. The hexagonal XRD pattern was still clearly observed in the hybrid material (GFP/SBA-15), as all the three main reflections were found (Fig. 1, curve B), indicating that the sonication and the GFP physical adsorption does not affect the framework integrity of the material. 

Tregunno, N.B. and Goff, H.D. 1996. Osmodehydrofreezing of apples Structural and textural effects. 

Sikorski, P., Atkins, E. D., and Serpell, L. C. (2003). Structure and texture of fibrous crystals formed by Alzheimer s abeta(ll-25) peptide fragment. Structure (Comb.) 11, 915—926. 

FIGURE 3.7 Diagram showing effects of sedimentary structures and textures on the flow of fluids in a point-bar sandstone reservoir. The cross-bedded unit is coarser grained and is inferred to have better reservoir properties (i.e., permeability) than the overlying rippled unit (A). Uneven advance of injected fluids illustrating permeability variations results from differences in reservoir quality. (Modified after Ebanks, 1987.)... 

Structural and Textural Properties ofNi-Ce02(Y203)-Zr02... 

Different alkanes from pentane to dodecane were incorporated in the micellar solution of CTMABr. In order to investigate the influence of the alkane chain length on the structural and textural properties of the formed mesoporous materials, as mentioned above, all syntheses were performed using a molar ratio of alkane/surfactant equal to 1.0. The crystallization time and temperature are respectively 8 days and 100°C... 

Structural and textural properties of zinc(II)-chromium(III) spinel oxides prepared using a hydrotalcite-like compound... 

Spinel oxides are important industrial catalysts, possessing good thermal and chemical stability and an ability to maintain catalytic activity at high temperatures. The study reported here is concerned with the properties ofZn(II)-Cr(III) spinel oxides prepared from a carbonate containing LDH precursor. For this study the spinel oxide was separated, by treatment with dilute mineral acid, from the oxide mixture (ZnO and ZnC O, ) obtained by the thermal decomposition of LDH. For comparison, Zn(II)-Cr(lII) spinel oxides were also prepared by more standard synthesis methods. Structural and textural properties were evaluated, using PXRD, TG/MS, FT-IR and N2 adsorption. 

Structural and Textural Properties of Zinc (ll)-Chromium (III) Spinel Oxides 691... 

Hardness as Influenced by Chemical and Phase Composition and by Structure and Texture... 

The Bohme s disc method for petrochemical estimation of rocks now used appears to be equivalent to the dynamic abrasion method only for monolithic, monomineral rocks. For rocks softer than silica or those composed of minerals of distinct hardness, porous or partially weathered, no correlation is found between Bohme s method and Vickers hardness or any other hardness, and abrasive action on a surface 42-49 cm2 in area does not allow estimation of the structural and textural specificity of orientations in the rock under test. 

The abrasiveness test results by Mackensen s method for selected cubes of known abrasiveness on Bohme s disc, given in Table 4.5.4, show very clearly a way of detecting inhomogeneities in rock hardness, induced by structural and textural differences. By this method we can observe the influence of pockets, laminae or veins occurring in a rock, which have a different composition from the typical rock structure, and also the influence of cracks and weathering of rock on its overall hardness (abrasiveness). In the tests with cubes (previously used for Bohme tests), some 24 measurements were taken in each case (four on each face) by the Mackensen method. This is sufficient to give a comprehensive characterization of rock hardness, not possible in the same time with any other method (a single... 

Table 1 gives composition, structural and textural characteristics of the catalysts. The evolution of the BET surface areas with the chromium content as well as the results of X ray analysis of the samples pretreated in air at 410°C. 

Composition, structure and texture of catalysts 1.3.1 General terms... 

Many but not all catalysts are porous materials in which most of the surface area is internal. It is sometimes convenient to speak of the structure and texture of such materials. The structure is defined by the distribution in space of the atoms or ions in the material part of the catalyst and, in particular, by the distribution at the surface. The texture is defined by the detailed geometry of the void space in the particles of catalyst. Porosity is a concept related to texture and refers to the pore space in a material. With zeolites, however, much of the porosity is determined by the crystal structure. 

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