2014 The trends in the cohesive energy, nearest-neighbour distance and compressibility of all sp bonded elements are discussed using a semiempirical tight binding approach. It is first shown that two very simple models describe these trends and also demonstrate the Grimm-Sommerfeld rule for elements with more than a half filled valence shell. A more complete numerical calculation is then perfor...

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Computational investigations have been performed into the behavior of an incompressible fluid flow in the vicinity of a plane symmetric channel contraction. Our aim is to determine the critical Reynolds number, above which the flow becomes asymmetric with respect to the channel geometry using the bifurcation diagram. Three channels, which are characterized by the contraction ratio, are studied ...

Let A be a finite real linear hyperplane arrangement in three dimensions. Suppose further that all the regions of A are isometric. We prove that A is necessarily a Coxeter arrangement. As it is well known that the regions of a Coxeter arrangement are isometric, this characterizes three-dimensional Coxeter arrangements precisely as those arrangements with isometric regions. It is an open questio...