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High resolution optical microscopy techniques have been employed to study the wetting properties of (5CB) x /(8CB)100-x (x=0, 10, 30, 50, 70, 90, and 100 wt %) binary mixture liquid crystal thin films above the isotropic transitions. Dewetting is found to occurr at T w=65 and 42.5°C for the 5CB and 8CB samples, respectively, and to depend strongly on the 5CB content in the mixtures. First-order wetting transitions were seen for pure 5CB and 8CB samples; a higher order wetting transitions were obtained for the mixtures. For thin film 5CB, a large hysteresis (ΔT=30°C) between wetting and dewetting during the heating and cooling is obtained. This hysteresis is compared with the corresponding values obtained for pure 8CB and mixture samples. Evidence of the formation of nematic layers on the surface of isotropic droplets was found. Attempts to extract values of the contact line tension for these materials are made. In this respect the applicability of the modified Young's equation is questionable

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The polarizabilities of the barium 6snf 3F 2 levels with principal quantum number n ranging from 11 to 40 have been measured in a high resolution laser-atomic-beam experiment. In Coulomb approximation the contributions to the polarizabilities of all known even-parity levels connected with the 3F 2 levels via the electric dipole operator have been calculated. In this way information on the to a large extent unknown 6sng 3G 3 Rydberg series is extracted. The results support earlier observations of a perturbation of this series in between n=18 and 19, but no evidence has been found for a perturbation near n= 14.

Purpose Educational policy is crucial to society. Its process is related to political, economic and cultural variables. Nevertheless, there is a paucity of research in the field of applied social sciences, about how educational policies help to achieve societal objectives and welfare. This study aims to assess the concept and features of school education in Egypt during 1990-2017. Design/methodology/approach Secondary data were collected using governmental reports and educational institutional reports and assessed through specialized focus groups. Findings Results showed that, despite the multiplicity of strategies to reform the educational system, achievements and outcomes of educational processes are modest, and the developmental status of Egypt is lower than that of other countries. Studying educational outcomes indicated that school-education suffered from the predominance of quantity over quality and a serious inability to meet requirements of new knowledge era. Originality/value A novel future-oriented proposal for context, ethos and reforming aspects of educational policy will be suggested.