178,925 research outputs found
Wind loads analysis at the anchorages of the Talavera de la Reina cable stayed bridge
No full textThis paper describes wind tunnel tests performed on wind tunnel models of the Talavera de la Reina cable stayed bridge. The work describes the aeroelastic model construction and it is focused on the evaluation and analysis of the mean and peak wind loads at the tower foundation and the cable anchorages since these data can be very useful by the bridge manufacturer as a support for the bridge design. The work is part of a complete wind tunnel study carried out to analyze the aeroelastic stability of the bridge
Complete extension of the symmetry axis of the Tomimatsu–Sato solution of the Einstein equations
No full textThe symmetry axis of the simplest Tomimatsu-Sato field is considered. Since this manifold is not geodesically complete for every value of the parameters occurring in the metric, a complete extension is given, and it is shown that its causal structure is very similar to that of the symmetry axis of the Kerr field
A Hopf Bundle over a Quantum Four-Sphere from the Symplectic Group
No full textWe construct a quantum version of the SU(2) Hopf bundle S7→S4. The quantum sphere Sq7 arises from the symplectic group Spq(2) and a quantum 4-sphere Sq4 is obtained via a suitable self-adjoint idempotent p whose entries generate the algebra A(Sq4) of polynomial functions over it. This projection determines a deformation of an (anti-)instanton bundle over the classical sphere S4. We compute the fundamental K-homology class of Sq4 and pair it with the class of p in the K -theory getting the value −1 for the topological charge. There is a right coaction of SUq (2) on Sq7 such that the algebra A(Sq7) is a non-trivial quantum principal bundle over A(Sq4) with structure quantum group A(SUq (2))
Representations of Virasoro and Kac-Moody algebras: An Algebraic geometrical point of view
No full textWe briefly recall what is kown as to the relations between representation theory of Virasoro and Kac-Moody algebras and the geometry of algebraic objects on suitable moduli spaces. Besides recalling the case of b-c-systems, we work out a geometric set up for the abelian Sugawara construction. A full understanding of the non abelian case requires more work on the side of geometrical representation theory
A borel-weil-bott approach to representations of slq(2, ℂ)
No full textWe use a quite concrete and simple realization of slq(2, C) involving finite difference operators. We interpret them as derivations (in the noncommutative sense) on a suitable graded algebra, which gives rise to the 'noncommutative' scheme P1 II P1* as the counterpart of the standard P1 = Sl(2, C)/B. © 1993 Kluwer Academic Publishers
NUT-like generalization of axisymmetric gravitational fields
No full textThe complex potential formulation of the axisymmetric problem discussed by Ernst enables us to construct new solutions from a given one, by multiplying the corresponding potential by a unit complex number. This rotation introduces naturally the NUT parameter in the metric. The generalized Kerr, Weyl, and Tomimatsu-Sato solutions are explicity constructed. Copyright © 1975 American Institute of Physics
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