Correlation interlayer

The ASA (now ANSI) performance code for Safety Glazing Materials was revised in 1966 to incorporate these improvements in windshield constmction. The addition of test no. 26 requiring support of a 2.3-kg ball dropped from 3.7 m defined this level of improvement. It was based on a correlation estabUshed between 10-kg, instmmented, head-form impacts on windshields, on 0.6 x 0.9-m flat laminates, and the standard 0.3 x 0.3-m laminate with the 2.3-kg ball (28). Crash cases involving the two windshield interlayer types were matched for car impact speeds and were compared (29). The improved design produced fewer, less extensive, and less severe facial lacerations than those produced in the pre-1966 models. 

To verify the mechanism presented, the quantum-chemical calculations of proton affinity, Aa, were carried out for modifiers, since the corresponding experimental data are quite rare. The calculations were performed for isolated molecules, since the properties of species in the interlayer space are probably closer to the gas phase rather than the liquid. The values of Ah were calculated as a difference in the total energy between the initial and protonated forms of the modifier. Energies were calculated using the TZV(2df, 2p) basis and MP2 electron correlation correction. Preliminarily, geometries were fully optimized in the framework of the MP2/6-31G(d, p) calculation. The GAMESS suite of ah initio programs was employed [10]. Comparison between the calculated at 0 K proton affinities for water (7.46 eV) and dioxane (8.50 eV) and the experimental data 7.50 eV and 8.42 eV at 298 K, respectively (see [11]), demonstrates a sufficient accuracy of the calculation. 

With an increase in size of the active metals, the interlayer interstitials between the triacontahedral and the penultimate icosidodecahedral shells appear to be occupied by smaller electronegative components, with variable occupancies. These interlayer interstitials are actually the centers of cubes and correspond to the Wyckoff 8c (1/4 V4 A) special position in 1/1 ACs. Strictly speaking, occupation at this site means that the structure is no longer YCd6-type but, for convenience, they are still referred to as Tsai-type phases. According to Piao and coworkers [94], occupation of these cube centers has strong correlation with the orientations of the innermost tetrahedra and distortions of the dodecahedra. 

An initial attempt was made to correlate the structural properties of the kl-(BEDT-TTF)2M(CF3)4(TCE) salts with their superconducting transition temperature [31]. The relationship between Tc and any single unit cell parameter failed to show any discemable trend. The best correlation was obtained by plotting Tc as a function of the b/c ratio, where b is the interlayer and c is an intralayer direction. A similar conclusion was reached through the determination of uniaxial pressure coefficients of p -(BEDT-TTF)2SF5CH2CF2S03 and k-(BEDT-TTF)2Cu(NCS)2 through the measurement of thermal expansion [32]. These results also indicated that expansion of the interlayer direction and compression of an intralayer direction... 

Where there is no correlation between the value of Oq and the apparent composition of the LDH, this may indicate that other non-LDH phases are also present [58]. It has often been observed in the case of Mg/Al LDHs with interlayer carbonate [51] or nitrate [55] anions that the value of Uo remains essentially constant 0.304 nm) for values of x > 0.33. In some cases the presence of an impurity such as gibbsite has been observed by XRD [55], sug-... 

Magnetic susceptibihty measurements [256] on Cu VCo VZn/Al LDHs indicate that the Cmie-Weiss law is obeyed with a Weiss temperature close to zero, indicating the lack of magnetic interactions between paramagnetic ions and thus a random distribution in the lattice. It has been proposed, however, that the catalytic activity of Mg Al LDHs n = 2,3) containing interlayer carbonate anions in the oxyethylation of 1-dodecanol with ethylene oxide can be correlated with the distance between AP" cations in ordered lattices [250]. 

Note 2 A SmF mesophase is characterised by in-plane short-range positional correlations and weak or no interlayer positional correlations. 

Tables IX and X contain correlation coefficients for the oxides and for the ions in their various structural positions. Correlations are relatively limited. There is a negative correlation between MgO and A1203 and between octahedral Mg2+ and octahedral Al3+ as would be expected. The same relation exists between ferric iron and aluminum and potassium and ferric iron. This latter correlation may reflect the fact that Fe3+ is the only major ion that can substitute in the illite structure and not increase the layer charge in fact, the layer charge may decrease (assuming tetrahedral Fe3+ is relatively uncommon). It is also possible that some of this Fe, can occur in the interlayer position. Fig.3 shows the graphical relation of K20 and Fe203.

Since this review was originally completed, Foster (1969) published a review in which similar conclusions are drawn about the glauconites and celadonites. The lack of correlation between iron and potassium content in glauconite is substantiated in her paper. Foster considered the process of glauconitization to be of two separate, unrelated processes, incorporation of iron into the crystal structure and fixation of potassium in interlayer positions, with incorporation of iron and development of negative layer charge preceding complete fixation of potassium . 

The negative relation between K2 O and Fe2 03 also occurs in the illites and has been discussed. Fe203 is positively correlated with H20+ and presumably negatively with layer charge. H20+ (greater than 110°C) and H20 (less than 110°C) are inversely related. These correlations suggest some of the H20+ may be trapped interlayer water not easily released (at 110°C) from the clays with a high proportion of contracted layers or that chloritic layers increase as the proportion of expandable layers decrease. 

Table LXVI shows the correlation coefficients obtained for the hard and soft types. The existence of two clay populations limits the meaning of correlations found for the combined data (Hinckley, 1961). In both groups K20 and mica and K20 and Fe203 are positively correlated. In addition, for the soft type there is a positive correlation between Fe203 and mica and negative correlations between mica and books, and Fe203 and books. These interrelations suggest, but do not prove, that books are derived from the mica and that much of the K20 and Fe203 may be present in the mica or that a leaching process that altered the mica and removed its interlayer K20 also removed the iron regardless of where it occurred (pyrite, anatase, iron oxides, etc.).

Nmr methods have unrivalled potential to explore interfaces, as this account has striven to show. We have been able to determine the mobility of hydrated sodium cations at the interface of the Ecca Gum BP montmorillonite, as 8.2 ns. We have been able to measure the translational mobility of water molecules at the interface, their diffusion coefficient is 1.6 10 15 m2.s. We have been able to determine also the rotational mobility of these water adsorbate molecules, it is associated to a reorientational correlation time of 1.6 ns. Furthermore, we could show the switch in preferred reorientation with the nature of the interlayer counterions, these water molecules at the interface tumbling about either the hydrogen bond to the anionic surface or around the electrostatic bond to the metallic cation they bear on their back. And we have been able to achieve the orientation of the Ecca Gum BP tactoids in the strong magnetic field of the nmr spectometer. 

Considering nonlinear effects in the vibrations of a crystal lattice (see, for example, [8]) it is necessary to take into account anharmonicity only in the terms connected to the largest interatomic forces, while the potential energy of weak forces of interlayer (or interchain) interactions, as well as noncentral forces should be considered in the harmonic approach. Therefore in (1) it is possible to neglect the summands, containing correlators of the atom displacements from various layers or chains, i.e. the correlators of... 

Correlation between calculated interaction energies of intercalated systems at the B3LYP/3-21G and the number of H-bonds, experimental interlayer distances [109, 114, 134] and calculated (B3LYP/3-21G ) molecular volumes of intercalated molecules ... 

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