48 research outputs found

    Feasibility of low energy radiative capture experiments at the LUNA underground accelerator facility

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    The LUNA (Laboratory Underground for Nuclear Astrophysics) facility has been designed to study nuclear reactions of astrophysical interest. It is located deep underground in the Gran Sasso National Laboratory, Italy. Two electrostatic accelerators, with 50 and 400 kV maximum voltage, in combination with solid and gas target setups allowed to measure the total cross sections of the radiative capture reactions 2^2H(p,γ\gamma)3He and 14^{14}N(p,γ\gamma)15^{15}O within their relevant Gamow peaks. We report on the gamma background in the Gran Sasso laboratory measured by germanium and bismuth germanate detectors, with and without an incident proton beam. A method to localize the sources of beam induced background using the Doppler shift of emitted gamma rays is presented. The feasibility of radiative capture studies at energies of astrophysical interest is discussed for several experimental scenarios.Comment: Submitted to Eur. Phys. J.

    Crisis and change in industrial relations in Central and Eastern Europe

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    This article introduces the special issue on industrial relations in Central and Eastern Europe since the financial and economic crisis. Already dependent economically on funding from the west, and lacking the robust industrial relations institutions traditional in much of Western Europe, countries in the region were particularly vulnerable. However, there are important cross-national differences, and the strategies of key actors have significantly affected the outcomes

    Preparation of Silicon Oxycarbide Composites Toughened by Inorganic Fibers via Pyrolysis of Precursor Siloxane Composites

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    The optimization of silicon oxycarbide (SiOC) synthesis (sol-gel/pyrolysis) is described, starting from methyltriethoxysilane, dimethyldiethoxysilane, tetraethoxysilane, ethyltriethoxysilane and propyltriethoxysilane. Variation of final elemental composition was tested via change of monomer ratios and combinations. The main aim was to achieve low weight losses during cure and pyrolysis and high micromechanical properties. Gas chromatography and mass spectroscopy was used to analyse the by-products of cure and pyrolysis, indicating a prominent role of cyclosiloxane and polyhedral oligomeric silsesquioxane (POSS) oligomers. Best results were obtained with high contents of methyltriethoxysilane in the monomers mixture
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