Liquid water models regularity

If.. separately, we knew the activity coefficients for bromine in carbon tetrachloride, we could u.se the data in the table to evaluate the activity coefficient of bromine in water (Problem 11.4-3). Since the regular solution model can be used to represent the Bri-CC mixture, we can then surmise that will be on the order of magnitude of unity. This suggests that y will be a large number, on the order of 100 or more. Such behavior for the activity coefficient o f the minor component is not unusual in mixtures of species with such different molecular characteristics as strongly quadrupolar liquid bromine and strongly polar and hydrogen-bonded water. H... 

The distribution of defects in mesophases is often regular, owing to their fluidity, and this introduces pattern repeats. For instance, square polygonal fields are frequent in smectics and cholesteric liquids. Such repeats occur on different scales - at the level of structural units or even at the molecular level. Several types of amphiphilic mesophase can be considered as made of defects . In many examples the defect enters the architecture of a unit cell in a three-dimensional array and the mesophase forms a crystal of defects [119]. Such a situation is found in certain cubic phases in water-lipid systems [120] and in blue phases [121] (see Chap. XII of Vol. 2 of this Handbook). Several blue phases have been modeled as being cubic centred lattices of disclinations in a cholesteric matrix . Mobius disclinations are assumed to join in groups of 4x4 or 8x8, but in nematics or in large-pitch cholesterics such junctions between thin threads are unstable and correspond to brief steps in recombinations. An isotropic droplet or a Ginsburg decrease to zero of the order parameter probably stabilizes these junctions in blue phases. 

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