3,546 research outputs found

    Non-Linear Static and Modal Analysis of Three Types of Cable-Stayed Bridges

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    This paper is concerned about the study of cable-stayed bridges having three spans with double plane of cables. Three common types of bridge arrangement are considered - harp, fan and radiating shapes. The influence of the arrangements of cables on the bridge deformation is examined. The relationship between the sag and the other parameters of cables for each type is presented. In the static analysis, the energy method, based on the minimization of the total potential energy of structural elements, via conjugate gradient technique is used. A computer program in FORTRAN language is used in the analysis of bridge model. Natural frequencies for the considered types of cable-stayed bridge are calculated, using the SAP2000 program. Keywords: Non-linear static analysis, cable structures, cable stayed bridges, minimization of potential energy, conjugate gradient method

    Football history: a German perspective on current research fields

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    In the last 25 years, German football has experienced several turning points. First, the collapse of communism in 1989 rendered necessary a complete reorganisation of the sport and football landscape in eastern Germany. Second, in parallel with the award in the year 2000 of the right to host the 2006 FIFA World Cup in the Federal Republic of Germany, a significant upturn took place in academic research on football. The reappraisal of the National Socialist era, in particular, has experienced a noticeable upswing since the year 2000. The present article focuses on several key thematic areas that shape current research and will shape research in the future. They include, first, the question of the character of the Vereine (here: football clubs) under the conditions of a communist dictatorship, and second, an increased interest in the biographical component of the history of the development of football. At the same time, it is clear that by now the question of a memory culture in football is no longer limited to national perspectives such as the reappraisal of the "Miracle of Bern". Rather, the dynamic development of European football renders possible the emergence of European realms of shared memory. At the same time, a boom in public engagement with football history can be observed in Germany and elsewhere. This holds true for both the social commemoration of footballers who were victims of war and tyranny and for popular cultural publications. In recent years, therefore, there has not only been an increase in the “museumisation” but also in the media marketing of football history. Thus, football history itself has become a market that is served by various stakeholders, such as clubs, companies, and the media

    VLBI measurement of the secular aberration drift

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    While analyzing decades of very long baseline interferometry (VLBI) data, we detected the secular aberration drift of the extragalatic radio source proper motions caused by the rotation of the Solar System barycenter around the Galactic center. Our results agree with the predicted estimate to be 4-6 micro arcseconds per year ({\mu}as/yr) towards {\alpha} = 266\circ and {\delta} = -29\circ. In addition, we tried to detect the quadrupole systematics of the velocity field. The analysis method consisted of three steps. First, we analyzed geodetic and astrometric VLBI data to produce radio source coordinate time series. Second, we fitted proper motions of 555 sources with long observational histories over the period 1990-2010 to their respective coordinate time series. Finally, we fitted vector spherical harmonic components of degrees 1 and 2 to the proper motion field. Within the error bars, the magnitude and the direction of the dipole component agree with predictions. The dipole vector has an amplitude of 6.4 \pm 1.5 {\mu}as/yr and is directed towards equatorial coordinates {\alpha} = 263\circ and {\delta} = -20\circ. The quadrupole component has not been detected. The primordial gravitational wave density, integrated over a range of frequencies less than 10-9 Hz, has a limit of 0.0042 h-2 where h is the normalized Hubble constant is H0/(100 km s-1)

    Position resolution and particle identification with the ATLAS EM calorimeter

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    In the years between 2000 and 2002 several pre-series and series modules of the ATLAS EM barrel and end-cap calorimeter were exposed to electron, photon and pion beams. The performance of the calorimeter with respect to its finely segmented first sampling has been studied. The polar angle resolution has been found to be in the range 50-60 mrad/sqrt(E (GeV)). The neutral pion rejection has been measured to be about 3.5 for 90% photon selection efficiency at pT=50 GeV/c. Electron-pion separation studies have indicated that a pion fake rate of (0.07-0.5)% can be achieved while maintaining 90% electron identification efficiency for energies up to 40 GeV.Comment: 32 pages, 22 figures, to be published in NIM

    The Energetics of Li Off-Centering in K1x_{1-x}Lix_xTaO3_3; First Principles Calculations

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    K1x_{1-x}Lix_{x}TaO3_3 (KLT) solid solutions exhibit a variety of interesting physical phenomena related to large displacements of Li-ions from ideal perovskite A-site positions. First-principles calculations for KLT supercells were used to investigate these phenomena. Lattice dynamics calculations for KLT exhibit a Li off-centering instability. The energetics of Li-displacements for isolated Li-ions and for Li-Li pairs up to 4th neighbors were calculated. Interactions between nearest neighbor Li-ions, in a Li-Li pair, strongly favor ferroelectric alignment along the pair axis. Such Li-Li pairs can be considered "seeds" for polar nanoclusters in KLT. Electrostriction, local oxygen relaxation, coupling to the KT soft-mode, and interactions with neighboring Li-ions all enhance the polarization from Li off-centering. Calculated hopping barriers for isolated Li-ions and for nearest neighbor Li-Li pairs are in good agreement with Arrhenius fits to experimental dielectric data.Comment: 14 pages including 10 figures. To Physical Review B. Replaced after corrections due to referees' remark

    Measurement of J/ψγηcJ/\psi\to\gamma\eta_{\rm c} decay rate and ηc\eta_{\rm c} parameters at KEDR

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    Using the inclusive photon spectrum based on a data sample collected at the J/ψJ/\psi peak with the KEDR detector at the VEPP-4M e+ee^+e^- collider, we measured the rate of the radiative decay J/ψγηcJ/\psi\to\gamma\eta_{\rm c} as well as ηc\eta_{\rm c} mass and width. Taking into account an asymmetric photon lineshape we obtained Γγηc0=2.98±0.180.33+0.15\Gamma^0_{\gamma\eta_{\rm c}}=2.98\pm0.18 \phantom{|}^{+0.15}_{-0.33} keV, Mηc=2983.5±1.43.6+1.6M_{\eta_{\rm c}} = 2983.5 \pm 1.4 \phantom{|}^{+1.6}_{-3.6} MeV/c2c^2, Γηc=27.2±3.12.6+5.4\Gamma_{\eta_{\rm c}} = 27.2 \pm 3.1 \phantom{|}^{+5.4}_{-2.6} MeV.Comment: 6 pages, 3 figure

    Precise measurement of RudsR_{\text{uds}} and RR between 1.84 and 3.72 GeV at the KEDR detector

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    The present work continues a series of the KEDR measurements of the RR value that started in 2010 at the VEPP-4M e+ee^+e^- collider. By combining new data with our previous results in this energy range we measured the values of RudsR_{\text{uds}} and RR at nine center-of-mass energies between 3.08 and 3.72 GeV. The total accuracy is about or better than 2.6%2.6\% at most of energy points with a systematic uncertainty of about 1.9%1.9\%. Together with the previous precise RR measurement at KEDR in the energy range 1.84-3.05 GeV, it constitutes the most detailed high-precision RR measurement near the charmonium production threshold.Comment: arXiv admin note: text overlap with arXiv:1610.02827 and substantial text overlap with arXiv:1510.0266

    Measurement of B(J/psi->eta_c gamma) at KEDR

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    We present a study of the inclusive photon spectrum from 6.3 million J/psi decays collected with the KEDR detector at the VEPP-4M e+e- collider. We measure the branching fraction of the radiative decay J/psi -> eta_c gamma, eta_c width and mass. Taking into account an asymmetric photon line shape we obtain: M(eta_c) = (2978.1 +- 1.4 +- 2.0) MeV/c^2, Gamma(eta_c) = (43.5 +- 5.4 +- 15.8) MeV, B(J/psi->eta_c gamma) = (2.59 +- 0.16 +- 0.31)%$.Comment: 6 pages, 1 figure. To be published in the proceedings of the 4th International Workshop on Charm Physics (Charm2010), October 21-24, 2010, IHEP, Beijin
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