23,324 research outputs found

    Out-of-plane seismic response of stone masonry walls: experimental and analytical study of real piers

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    This paper presents the application of an existing simplified displacement-based procedure to the characterization of the nonlinear force-displacement relationship for the out-of-plane behaviour of unreinforced traditional masonry walls. According to this procedure, tri-linear models based on three different energy based criteria were constructed and confronted with three experimental tests on existing stone masonry constructions. Moreover, a brief introduction is presented regarding the main characteristics of the in situ cyclic testing recently carried out using distributed loads, as well as results obtained during the experimental campaigns performed. The comparison between the experimental and the analytical results are presented and discussed

    Enhancing li→3ljl_i \to 3 l_j with the Z0Z^0-penguin

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    Lepton flavor violation (LFV) has been observed in neutrino oscillations. For charged lepton FV decays only upper limits are known, but sizable branching ratios are expected in many neutrino mass models. High scale models, such as the classical supersymmetric seesaw, usually predict that decays li→3ljl_i \to 3 l_j are roughly a factor α\alpha maller than the corresponding decays li→ljγl_i \to l_j \gamma. Here we demonstrate that the Z0Z^0-penguin diagram can give an enhancement for decays li→3ljl_i \to 3 l_j in many extensions of the MSSM. We first discuss why the Z0Z^0-penguin is not dominant in the MSSM with seesaw and show that much larger contributions from the Z0Z^0-penguin are expected in general. We then demonstrate the effect numerically in two example models, namely, the supersymmetric inverse seesaw and R-parity violating supersymmetry.Comment: 5 pages; v2: minor corrections, final version to appear in PR

    Further results on elementary Lie algebras and Lie A-algebras.

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    A finite-dimensional Lie algebra L over a field F of characteristic zero is called elementary if each of its subalgebras has trivial Frattini ideal; it is an A-algebra if every nilpotent subalgebra is abelian. This paper is a continuation of the study of these algebras initiated by the authors in a previous paper. If we denote by A\mathcal{A}, G\mathcal{G}, E\mathcal{E}, L\mathcal{L}, Φ\Phi the classes of A-algebras, almost algebraic algebras, E-algebras, elementary algebras and ϕ\phi-free algebras respectively, then it is shown that: \mathcal{L} \subset \Phi \subset \mathcal{G} \mathcal{L} \subset \mathcal{A} \subset \mathcal{E} \mathcal{G} \cap \mathcal{A} = \mathcal{L}. It is also shown that if L is a semisimple Lie algebra all of whose minimal parabolic subalgebras are ϕ\phi-free then L is an A-algebra, and hence elementary. This requires a number of quite delicate properties of parabolic subalgebras. Finally characterisations are given of EE-algebras and of Lie algebras all of whose proper subalgebras are elementary

    eta - eta' - glueball mixing

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    We have revisited glueball mixing with the pseudoscalar mesons in the MIT bag model scheme. The calculation has been performed in the spherical cavity approximation to the bag using two different fermion propagators, the cavity and the free propagators. We obtain a very small probability of mixing for the eta at the level of $0.04-0.1% and a bigger for the eta' at the level of 4-12%. Our results differ from previous calculations in the same scheme but seem to agree with the experimental analysis. We discuss the origin of our difference which stems from the treatment of our time integrations.Comment: 21 pages, 7 figure

    Edible films and coatings : from novel materials to nanotechnological applications

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    The food industry constantly seeks new strategies to increase the storability of foods and to improve the existent technology. In the last years, edible coatings/films have been considered as one of the potential technologies that can achieve those objectives, ensuring the microbial safety and the preservation of food from the influence of external factors. Significant innovations constantly appear in food packaging, always with the objective of creating a more efficient quality preservation system while improving foods’ attractiveness and marketability. One of the main worries while developing such innovations is the use of renewable sources for the packaging materials, such as hydrocolloids from biological origin, and the incorporation of functional ingredients that can be used e.g. as antioxidants and antimicrobial agents. Our work until the present moment has involved most of the important features of this technology, namely: materials (new sources of raw materials for the production of edible coatings/films were sought and the materials were characterized); properties of the coatings/films (physical, chemical, thermal, mechanical and transport properties - in particular those related to moisture, oxygen, carbon dioxide exchange through the coating/film - were evaluated); incorporation of active compounds (natural antimicrobials and antioxidants were incorporated); applications to food products and its consequences in e.g. the extension of their shelf life. Finally, nano-engineered coating and films are being developed, and a report will be given on that subject with the latest developments achieved in our lab

    Processamento mínimo de alimentos

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