226 research outputs found

    Development of Flutter Constraints for High-fidelity Aerostructural Optimization

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143080/1/6.2017-4455.pd

    RANS-based Aerodynamic Shape Optimization of a Blended-Wing-Body Aircraft

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106453/1/AIAA2013-2586.pd

    Geometry and Structural Modeling for High-Fidelity Aircraft Conceptual Design Optimization

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140431/1/6.2014-2041.pd

    The Hyperfine Splitting in Charmonium: Lattice Computations Using the Wilson and Clover Fermion Actions

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    We compute the hyperfine splitting mJ/ψ−mηcm_{J/\psi}-m_{\eta_c} on the lattice, using both the Wilson and O(a)O(a)-improved (clover) actions for quenched quarks. The computations are performed on a 243×4824^3\times48 lattice at ÎČ=6.2\beta = 6.2, using the same set of 18 gluon configurations for both fermion actions. We find that the splitting is 1.83\err{13}{15} times larger with the clover action than with the Wilson action, demonstrating the sensitivity of the spin-splitting to the magnetic moment term which is present in the clover action. However, even with the clover action the result is less than half of the physical mass-splitting. We also compute the decay constants fηcf_{\eta_c} and fJ/ψ−1f^{-1}_{J/\psi}, both of which are considerably larger when computed using the clover action than with the Wilson action. For example for the ratio fJ/ψ−1/fρ−1f^{-1}_{J/\psi}/f^{-1}_{\rho} we find 0.32\err{1}{2} with the Wilson action and 0.48±30.48\pm 3 with the clover action (the physical value is 0.44(2)).Comment: LaTeX file, 8 pages and two postscript figures. Southampton Preprint: SHEP 91/92-27 Edinburgh Preprint: 92/51

    Aerodynamic Design Optimization Studies of a Blended-Wing-Body Aircraft

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    Quenched QCD with O(a) improvement: I. The spectrum of light hadrons

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    We present a comprehensive study of the masses of pseudoscalar and vector mesons, as well as octet and decuplet baryons computed in O(a) improved quenched lattice QCD. Results have been obtained using the non-perturbative definition of the improvement coefficient c_sw, and also its estimate in tadpole improved perturbation theory. We investigate effects of improvement on the incidence of exceptional configurations, mass splittings and the parameter J. By combining the results obtained using non-perturbative and tadpole improvement in a simultaneous continuum extrapolation we can compare our spectral data to experiment. We confirm earlier findings by the CP-PACS Collaboration that the quenched light hadron spectrum agrees with experiment at the 10% level.Comment: 36 pages, 7 postscript figures, REVTEX; typo in Table XVIII corrected; extended discussion of finite-size effects in sections III and VII; version to appear in Phys. Rev.

    Gauge Invariant Smearing and Matrix Correlators using Wilson Fermions at beta=6.2

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    We present an investigation of gauge invariant smearing for Wilson fermions on a 243×4824^3 \times 48 lattice at ÎČ=6.2\beta = 6.2. We demonstrate a smearing algorithm that allows a substantial improvement in the determination of the baryon spectrum obtained using propagators smeared at both source and sink, at only a small computational cost. We investigate the matrix of correlators constructed from local and smeared operators, and are able to expose excited states of both the mesons and baryons.Comment: at lattice `92. 4 pages latex + 3 postscript figures. Edinburgh preprint: 92/51

    The limits of social class in explaining ethnic gaps in educational attainment

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    This paper reports an analysis of the educational attainment and progress between age 11 and age 14 of over 14,500 students from the nationally representative Longitudinal Study of Young People in England (LSYPE). The mean attainment gap in national tests at age 14 between White British and several ethnic minority groups were large, more than three times the size of the gender gap, but at the same time only about one-third of the size of the social class gap. Socio-economic variables could account for the attainment gaps for Black African, Pakistani and Bangladeshi students, but not for Black Caribbean students. Further controls for parental and student attitudes, expectations and behaviours indicated minority ethnic groups were on average more advantaged on these measures than White British students, but this was not reflected proportionately in their levels of attainment. Black Caribbean students were distinctive as the only group making less progress than White British students between age 11 and 14 and this could not be accounted for by any of the measured contextual variables. Possible explanations for the White British-Black Caribbean gap are considered
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