17,867 research outputs found

    On the κ\kappa-Dirac Oscillator revisited

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    This Letter is based on the κ\kappa-Dirac equation, derived from the κ\kappa-Poincar\'{e}-Hopf algebra. It is shown that the κ\kappa-Dirac equation preserves parity while breaks charge conjugation and time reversal symmetries. Introducing the Dirac oscillator prescription, ppimωβr\mathbf{p}\to\mathbf{p}-im\omega\beta\mathbf{r}, in the κ\kappa-Dirac equation, one obtains the κ\kappa-Dirac oscillator. Using a decomposition in terms of spin angular functions, one achieves the deformed radial equations, with the associated deformed energy eigenvalues and eigenfunctions. The deformation parameter breaks the infinite degeneracy of the Dirac oscillator. In the case where ε=0\varepsilon=0, one recovers the energy eigenvalues and eigenfunctions of the Dirac oscillator.Comment: 5 pages, no figures, accepted for publication in Physics Letters

    Sustainable agriculture – Poland and Portugal

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    Papers from communications presented at the Workshop “Agriculture Sustainability, Poland-Portugal”, held in the University of Évora, Portugal, December, 2013

    Subsonic aerodynamic and flutter characteristics of several wings calculated by the SOUSSA P1.1 panel method

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    The SOUSSA (steady, oscillatory, and unsteady subsonic and supersonic aerodynamics) program is the computational implementation of a general potential flow analysis (by the Green's function method) that can generate pressure distributions on complete aircraft having arbitrary shapes, motions and deformations. Some applications of the initial release version of this program to several wings in steady and oscillatory motion, including flutter are presented. The results are validated by comparisons with other calculations and experiments. Experiences in using the program as well as some recent improvements are described

    Herpetofauna, Santa Edwiges I and II hydroelectric power plants, state of Goiás, Brazil

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    This paper presents a check list of amphibians and reptiles of the area under the influence of Santa Edwiges I and IIsmall hydroelectric power plants on Rio Buritis, state of Goiás, Brazil. The list was the result of faunal rescueoperations carried out between 31 August and 29 September 2005 (Santa Edwiges II) and between 30 July and 12September 2006 (Santa Edwiges I). The list comprises 30 species of amphibians belonging to 16 genera and 8 families(Caeciliidae, Bufonidae, Cycloramphidae, Hylidae, Brachycephalidae, Leiuperidae, Leptodactylidae, andMicrohylidae), and 45 species of reptiles belonging to 38 genera and 16 families (Amphisbaenidae, Anguidae,Gekkonidae, Gymnophtalmidae, Polychrotidae, Scincidae, Teiidae, Tropiduridae, Anomalepididae, Leptotyphlopidae,Typhlopidae, Boidae, Colubridae, Dipsadidae, Elapidae, and Viperidae)

    Pressure measurements on a rectangular wing with a NACA0012 airfoil during conventional flutter

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    The Structural Dynamics Division at NASA LaRC has started a wind tunnel activity referred to as the Benchmark Models Program. The primary objective of the program is to acquire measured dynamic instability and corresponding pressure data that will be useful for developing and evaluating aeroelastic type CFD codes currently in use or under development. The program is a multi-year activity that will involve testing of several different models to investigate various aeroelastic phenomena. The first model consisted of a rigid semispan wing having a rectangular planform and a NACA 0012 airfoil shape which was mounted on a flexible two degree-of-freedom mount system. Two wind-tunnel tests were conducted with the first model. Several dynamic instability boundaries were investigated such as a conventional flutter boundary, a transonic plunge instability region near Mach = 0.90, and stall flutter. In addition, wing surface unsteady pressure data were acquired along two model chords located at the 60 to 95-percent span stations during these instabilities. At this time, only the pressure data for the conventional flutter boundary is presented. The conventional flutter boundary and the wing surface unsteady pressure measurements obtained at the conventional flutter boundary test conditions in pressure coefficient form are presented. Wing surface steady pressure measurements obtained with the model mount system rigidized are also presented. These steady pressure data were acquired at essentially the same dynamic pressure at which conventional flutter had been encountered with the mount system flexible

    NACA0012 benchmark model experimental flutter results with unsteady pressure distributions

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    The Structural Dynamics Division at NASA Langley Research Center has started a wind tunnel activity referred to as the Benchmark Models Program. The primary objective of this program is to acquire measured dynamic instability and corresponding pressure data that will be useful for developing and evaluating aeroelastic type computational fluid dynamics codes currently in use or under development. The program is a multi-year activity that will involve testing of several different models to investigate various aeroelastic phenomena. This paper describes results obtained from a second wind tunnel test of the first model in the Benchmark Models Program. This first model consisted of a rigid semispan wing having a rectangular planform and a NACA 0012 airfoil shape which was mounted on a flexible two degree of freedom mount system. Experimental flutter boundaries and corresponding unsteady pressure distribution data acquired over two model chords located at the 60 and 95 percent span stations are presented
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