1,451 research outputs found

    Maintenance/repair and production-oriented life cycle cost/earning model for ship structural optimisation during conceptual design stage

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    The aim of this paper is to investigate the effect of the change in structural weight due to optimisation experiments on life cycle cost and earning elements using the life cycle cost/earning model, which was developed for structure optimisation. The relation between structural variables and relevant cost/earning elements are explored and discussed in detail. The developed model is restricted to the relevant life cycle cost and earning elements, namely production cost, periodic maintenance cost, fuel oil cost, operational earning and dismantling earning. Therefore it is important to emphasise here that the cost/earning figure calculated through the developed methodology will not be a full life cycle cost/earning value for a subject vessel, but will be the relevant life cycle cost/earning value. As one of the main focuses of this paper is the maintenance/repair issue, the data was collected from a number of ship operators and was solely used for the purpose of regression analysis. An illustrative example for a chemical tanker is provided to show the applicability of the proposed approac

    Juglone effects on seedling growth in intact and coatless seeds of muskmelon

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    Elongation, fresh and dry weights of muskmelon seedlings (Cucumis melo cv. Ký kavunu) were enhanced by juglone in intact seeds. In the case of coatless seeds, root elongation decreased but fresh and dry weight of the seedlings were increased by juglone. While protein content was slightly increased by juglone in cotyledons of intact seeds, it did not change significantly in coatless seeds. Catechol oxidizing activity of polyphenol oxidase (PPO) enzyme increased in cotyledons of juglone treated intactseeds whereas it did not change significantly in coatless seeds

    Constraints on Dark Photon from Neutrino-Electron Scattering Experiments

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    A possible manifestation of an additional light gauge boson AA^\prime, named as Dark Photon, associated with a group U(1)BLU(1)_{\rm B-L} is studied in neutrino electron scattering experiments. The exclusion plot on the coupling constant gBLg_{\rm B-L} and the dark photon mass MAM_{A^\prime} is obtained. It is shown that contributions of interference term between the dark photon and the Standard Model are important. The interference effects are studied and compared with for data sets from TEXONO, GEMMA, BOREXINO, LSND as well as CHARM II experiments. Our results provide more stringent bounds to some regions of parameter space.Comment: 22 pages, 6 figures, 2 tables, text improved, fig.6 updated, references adde

    Heavy ZZ^\prime Bosons in the Secluded U(1)U(1)^\prime Model at Hadron Colliders

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    We study ZZ' phenomenology at hadron colliders in an U(1)U(1)' extended MSSM. We choose a U(1)U(1)' model with a secluded sector, where the tension between the electroweak scale and developing a large enough mass for ZZ' is resolved by incorporating three additional singlet superfields into the model. We perform a detailed analysis of the production, followed by decays, including into supersymmetric particles, of a ZZ' boson with mass between 4 and 5.2 TeV, with particular emphasis on its possible discovery. We select three different scenarios consistent with the latest available experimental data and relic density constraints, and concentrate on final signals with two leptons, four leptons and six leptons. Including the SM background from processes with two, three or four vector bosons, we show the likelihood of observing a ZZ^\prime boson is not promising for the HL-LHC at 14 TeV. While at 27 and 100 TeV, the situation is more optimistic, and we devise specific benchmark scenarios which could be observed.Comment: 21 pages, 9 figures, 9 tables, published version; title changed, more references and a new table adde

    Signatures for doubly-charged Higgsinos at colliders

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    Several supersymmetric models with extended gauge structures predict light doubly-charged Higgsinos. Their distinctive signature at the large hadron collider is highlighted by studying their production and decay characteristics.Comment: 3 pages, 4 figures, Latex. Submitted for SUSY 2008 proceeding

    Sneutrino Dark Matter: Symmetry Protection and Cosmic Ray Anomalies

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    We present an R-parity conserving model of sneutrino dark matter within a Higgs-philic U(1)' extension of the minimal supersymmetric standard model. In this theory, the mu parameter and light Dirac neutrino masses are generated naturally upon the breaking of the U(1)' gauge symmetry. The leptonic and hadronic decays of sneutrinos in this model, taken to be the lightest and next-to-lightest superpartners, allow for a natural fit to the recent results reported by the PAMELA experiment.Comment: Revised to match the published version; 11 pages (2 column format), 1 table, 6 figures, to appear in PR

    Comparison of Electron and Hole Charge-Discharge Dynamics in Germanium Nanocrystal Flash Memories

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    Cataloged from PDF version of article.Electron and hole charge and discharge dynamics are studied on plasma enhanced chemical vapor deposition grown metal-oxide-silicon germanium nanocrystal flash memory devices. Electron and hole charge and discharge currents are observed to differ significantly and depend on annealing conditions chosen for the formation of nanocrystals. At low annealing temperatures, holes are seen to charge slower but to escape faster than electrons. They discharge slower than electrons when annealing temperatures are raised. The results suggest that discharge currents are dominated by the interface layer acting as a quantum well for holes and by direct tunneling for elec-trons. (c) 2008 American Institute of Physics
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