8,927 research outputs found

    THE APPLICATION OF TIO2 NANOPARTICLES ON WASTEWATER TREATMENT

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    Master'sMASTER OF SCIENC

    Branching Fractions and CP Asymmetries of the Quasi-Two-Body Decays in BsK0(K0)K±πB_{s} \to K^0(\overline K^0)K^\pm \pi^\mp within PQCD Approach

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    Motivated by the first untagged decay-time-integrated amplitude analysis of BsKSKπ±B_s \to K_SK^{\mp}\pi^{\pm} decays performed by LHCb collaboration, where the decay amplitudes are modeled to contain the resonant contributions from intermediate resonances K(892)K^*(892), K0(1430)K_0^*(1430) and K2(1430)K_2^*(1430), we comprehensively investigate the quasi-two-body BsK0/K0K±πB_{s} \to K^0/\overline{\kern -0.2em K}^0 K^{\pm}\pi^{\mp} decays, and calculate the branching fractions and the time-dependent CPCP asymmetries within the perturbative QCD approach based on the kTk_T factorization. In the quasi-two-body space region the calculated branching fractions with the considered intermediate resonances are in good agreement with the experimental results of LHCb by adopting proper KπK\pi pair wave function, describing the interaction between the kaon and pion in the KπK\pi pair. Furthermore,within the obtained branching fractions of the quasi-two-body decays, we also calculate the branching fractions of corresponding two-body decays, and the results consist with the LHCb measurements and the earlier studies with errors. For these considered decays, since the final states are not flavour-specific, the time-dependent CPCP could be measured. We calculate six CPCP-violation observables, which can be tested in the ongoing LHCb experiment.Comment: 20 page

    Cabibbo-Kobayashi-Maskawa-favored BB decays to a scalar meson and a DD meson

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    Within the perturbative QCD approach, we investigated the Cabibbo-Kobayashi-Maskawa-favored BDSB \to \overline{D} S ("SS" denoting the scalar meson) decays on the basis of the two-quark picture. Supposing the scalar mesons are the ground states or the first excited states, we calculated the the branching ratios of 72 decay modes. Most of the branching ratios are in the range 10410^{-4} to 10710^{-7}, which can be tested in the ongoing LHCb experiment and the forthcoming Belle-II experiment. Some decays, such as B+D()0a0+(980/1450)B^+ \to \overline{D}^{(*)0} a_0^+(980/1450) and B+D()a0+(980/1450)B^+ \to D^{(*)-} a_0^+(980/1450), could be used to probe the inner structure and the character of the scalar mesons, if the experiments are available. In addition, the ratios between the Br(B0D()0σ)Br(B^0\to \overline{D}^{(*)0}\sigma) and Br(B0D()0f0(980))Br(B^0\to \overline{D}^{(*)0}f_0(980)) provide a potential way to determine the mixing angle between σ\sigma and f0(980)f_0(980). Moreover, since in the standard model these decays occur only through tree operators and have no CPCP asymmetries, any deviation will be signal of the new physics beyond the standard model.Comment: 2 figures, 6 table

    On the turbulent flow models in modelling of omni-flow wind turbine

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    Yong Chen, Pei Ying, Yigeng Xu, Yuan Tian, 'On the turbulent flow models in modelling of omni-flow wind turbine', paper presented at The International Conference on Next Generation Wind Energy (ICNGWE2014), the Universidad Europa de Madrid, Madrid, Spain, 7th-10th October 2014.The computational fluid dynamics (CFD) has a wide application in the wind energy industry. In CFD simulations, a turbulence model plays a significantly important role in accuracy and resource cost. In this paper, a novel wind turbine, omni-flow wind turbine, was investigated with different turbulence models. Four turbulence models, standard k-ε, realizable k-ε, standard k-ω and SST k-ω models, were employed for this wind turbine in order to assess the best numerical configuration. The performance of these four turbulence models was validated with wind tunnel tests. It is evident that the realizable k-ε turbulence model is most suitable to simulate this novel wind turbine

    Spectral Method for Fatigue Damage Assessment of Structures with Uncertain Parameters

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    This study presents a spectral method for fatigue damage evaluation of linear structures with uncertain-but-bounded parameters subjected to the stationary multi-correlated Gaussian random excitation. The first step of the proposed method is to model uncertain parameters by introducing interval theory. Within the framework of interval analysis, the approximate expressions of the bounds of spectral moments of generic response are obtained by the improved interval analysis via the Extra Unitary Interval and Interval Rational Series Expansion. Based on the cumulative damage theory and the Tovo-Benasciutti method, the lower and upper bounds of expected fatigue damage rate are accurately evaluated by properly combining the bounds of the spectral parameters of the power density spectral function of stress of critical points. Finally, a numerical example concerning a truss under random excitation is used to illustrate the accuracy and efficiency of the proposed method by comparing with the vertex method
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