Stability of structures

H.D. Goff Formation and Stabilization of Structure in Ice-Cream and Related Products. Curr. Opin. Colloid Interface Sci. 7, 432 (2002). 

Makino, T. Nakamura, T. Sugahara, T. Ohgaki, K. (2004). Thermodynamic stability of structure-H hydrates of methylcyclopentane and cyclooctane helped by methane. Fluid Phase Equilibria, 218, 235-238. 

Members of both structural families of serine proteinases, the trypsinlike and the subtilisin-like, have been found to bind Ca " (references in Tables 1 and II). The role of Ca " in all of these proteolytic enzymes appears to be one of stabilization of structure and/or maintenance of... 

In an ideal world, crystals would be perfect or stoichiometric with constant composition. But like people crystals are not exempt from imperfections or defects. Crystals with variable composition are termed non-stoichiometric crystals. The defect chemistry of oxides is enormously complex and is extremely vital to their properties. It has involved extensive research in many laboratories and is providing extraordinary insights into structural variations, the stability of structures and the formation of new structures. Here, we first define order-disorder phenomena that are commonly associated with oxides and describe our current understanding of them. The disorder or non-stoichiometry plays a crucial role in oxide applications including catalysis and it is therefore of paramount importance. 

The relative stability of structural types with even-membered rings can often be inferred from the dimensionless shape parameters, s, which from eqn (4.58) is given by... 

Microscopic structure of texturized water-extracted soy flour and texturized soy concentrate were quite similar to that of texturized soy flour. Scanning electron microgrpahs showed that water extraction of soy flours had little effect on morphological characteristics of texturized soy products (Figure 10). Solubility of soluble sugars was not affected by texturization, whereas solubility of proteins decreased sharply when soy flour was texturized (Table VII). It appears that soluble sugars did not interact with proteins during texturization. Based upon results of microscopy and solubility studies, it is reasonable to speculate that natural soluble carbohydrates are not required (do not play an important role) in development of texture or stabilization of structure. 

Taking into consideration die stability of structures involving C-Si bonds, it is evident that the basic chain itself must be comparable in its stability to that of silica and the silicate minerals, and if the R substituents contain no carbon-to-earbon bonds, as for example with methyl groups, the combination should have excellent thermal stability and chemical resistance. 

The interest in periodically forced systems extends beyond performance considerations for a single reactor. Stability of structures and control characteristics of chemical plants are determined by their responses to oscillating loads. Epidemics and harvests are governed by the cycle of seasons. Bifurcation and stability analysis of periodically forced systems is especially important in the... 

The effect of concentration of the selective solvent for PS on the PEO crystallization was also explored by Gervais and Gallot (1973a). As expected, increasing the solvent concentration reduced the melting temperature of the PEO. It was found that for a given copolymer at a fixed temperature the number of folds increased (thus the PEO layer thickness decreased) as the solvent concentration increased. This is illustrated in Fig. 5.26 which shows regions of stability of structures with different number of PEO folds in the temperature-concentration plane.The PS layer was observed to swell (and the PS interfacial area to increase)... 

Baldock, J. A. (2002). Interactions of organic materials and microorganisms with minerals in stabilization of structure. In Interactions Between Soil Particles and Microorganisms. Impact on the Terrestrial Ecosystem, Huang, P. M., Bollag, J.-M., and Senesi, N., eds., IUPAC Series on Analytical and Physical of Environmental Systems. Vol. 8, John Wiley Sons, Chichester, UK, pp. 85-131. 

The results of calculations are presented in Table 4. The energy of each of intermolecular bonds decrease with increasing of the number of molecules in cluster but the intermolecular bonds energy per one molecule (or per one carbon atom) and as sequence stability of structure increase with growth of cluster size. 

Similar factors account for the relative reactivity of oxygen-containing compounds. Thus 1-benzopyrylium (11.44) is very unreactive, but more reactive than pyrylium. The least reactive sites will be the 2- and 4-positions and in the benzenoid ring it will be the 7-position because of the high stability of the p-quininoid structure (11.49). For 2-benzopyrylium, the least reactive sites will be the 1- and then the 6-position, the latter arising from the high stability of structure 11.50 11.50 is more stable than 11.49, so the 6-position of 11.50 will be less reactive than the 7-position of 11.49. 

Goff, H.D. 2002. Formation and stabilization of structure in ice cream and related products. Curr. Op. Coll. Interface Sci. 7, 432-437. 

We have studied the transformations of the CsCl + KCl and CsCl + CsBr solid solutions in order to find the limitations and applicability of the Born treatment in explaining the two entirely different behaviours of the solid solutions of these two systems. Such a study is of value since theoretical approaches to explain the relative stabilities of structures of ionic solids have not been quite successful, and it is important to explain the relative stabilities of at least the two simplest structure types in ionic solids, viz., the NaCl and CsCl structures. We also wished to find out whether the first order characteristics of Pm3m-Fm3m transitions are retained in the solid solutions. We have therefore examined the crystallography of the Pm3m and Fm3m phases of the solid solutions as functions of temperature from these data, coefficients of expansion of the two structures have been calculated. 

The value of (8bl + 6b2) thus calculated is 76867 x 10-12 ergs mol-1. The A /ss of solid solutions of CsCl and CsBr were evaluated (eqn. (1)) for different values of b2 (in the range 0-900 x 10-12 erg mol-1) using the r0 values from table 2. The results are shown diagramatically in fig. 3, the values of b, and b2 are 9257 x 10-12 and 468 x 10-12 erg mol-1 respectively when (6b2/%b1 + 6b2)csci (6b2l%bi + 6b2)csB,- The AUs s remains nearly constant with the % CsBr when b2 is between 400 and 500 x 10-12 erg mol-1. Thus, curves 3 and 4 of fig. 3 closely represent the experimentally observed situation. Thus, the Born model of ionic solids describes the relative stabilities of structures of alkali halides in widely different situations as manifested here by the CsCl+KCl and CsCl + CsBr systems. 

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