7,933 research outputs found

    An Overview of China's Environmental Governance Problems

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    The Wind Turbine industry continues to drive towards high market penetrationand profitability. In order to keep Wind Turbines in field for as long as possiblecomputational analysis tools are required. The open source tool QBlade[38] softwarewas extended to now contain routines to analyse the structural properties of WindTurbine blades. This was achieved using 2D integration methods and a Tapered Euler-Bernoulli beam element in order to find the mode shapes and 2D sectional properties.This was a key step towards integrating the National Renewable Energy LaboratoriesFAST package[32] which has the ability to analyse Aeroelastic Responses. The QFEMmodule performed well for the test cases including: hollow isotropic blade, rotatingbeam and tapered beam. Some improvements can be made to the torsion estimationof the 2D sections but this has no effect on the mode shapes required for the FASTsimulations

    Phase-sensitive quantum effects in Andreev conductance of the SNS system of metals with macroscopic phase breaking length

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    The dissipative component of electron transport through the doubly connected SNS Andreev interferometer indium (S)-aluminium (N)-indium (S) has been studied. Within helium temperature range, the conductance of the individual sections of the interferometer exhibits phase-sensitive oscillations of quantum-interference nature. In the non-domain (normal) state of indium narrowing adjacent to NS interface, the nonresonance oscillations have been observed, with the period inversely proportional to the area of the interferometer orifice. In the domain intermediate state of the narrowing, the magneto-temperature resistive oscillations appeared, with the period determined by the coherence length in the magnetic field equal to the critical one. The oscillating component of resonance form has been observed in the conductance of the macroscopic N-aluminium part of the system. The phase of the oscillations appears to be shifted by π\pi compared to that of nonresonance oscillations. We offer an explanation in terms of the contribution into Josephson current from the coherent quasiparticles with energies of order of the Thouless energy. The behavior of dissipative transport with temperature has been studied in a clean normal metal in the vicinity of a single point NS contact.Comment: 9 pages, 7 figures, to be published in Low Temp. Phys., v. 29, No. 12, 200

    On the Antenna Beam Shape Reconstruction Using Planet Transit

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    The calibration of the in-flight antenna beam shape and possible beamdegradation is one of the most crucial tasks for the upcoming Planck mission. We examine several effects which could significantly influence the in-flight main beam calibration using planet transit: the problems of the variability of the Jupiter's flux, the antenna temperature and passing of the planets through the main beam. We estimate these effects on the antenna beam shape calibration and calculate the limits on the main beam and far sidelobe measurements, using observations of Jupiter and Saturn. We also discuss possible effects of degradation of the mirror surfaces and specify corresponding parameters which can help us to determine these effects.Comment: 10 pages, 8 figure

    The Propagation of Guided Periodic Cylinder Structure

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    [[abstract]]In this paper, an approach using the mode-matching technique in conjunction with the Floquet theorem is employed to analyze the periodically loaded corrugated cylindrical waveguides. The cylindrical waveguide under analysis consists of a periodically loaded corrugated center metallic cylinder covered with layered dielectrics. In addition, the geometry and the number of layers of the corrugation can be arbitrary. The outermost layer of the cylindrical periodic structure can be a shielding conductor. To analyze, we represent the electromagnetic fields in each layer with the appropriate eigenmode functions. Then boundary conditions at all interfaces are imposed to obtain a system characteristic equation, from which the propagation constant of the whole periodic structure can be solved. In this work, effects of the period, width, and depth of the corrugation as well as the dielectric constants of the cover layers on the dispersion property are studied. The location of the pass band and stop band of the periodically loaded corrugated cylindrical waveguides are also examined

    Verifiable Model of Neutrino Masses from Large Extra Dimensions

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    We propose a new scenario of neutrino masses with a Higgs triplet (ξ++,ξ+,ξ0)(\xi^{++},\xi^+,\xi^0) in a theory of large extra dimensions. Lepton number violation in a distant brane acts as the source of a very small trilinear coupling of ξ\xi to the standard Higgs doublet in our brane. Small realistic Majorana neutrino masses are \underline{naturally} obtained with the fundamental scale MO(1)M_* \sim {\cal O}(1) TeV, foretelling the possible discovery of ξ\xi (m_\xi\lsim M_*) at future colliders. Decays of ξ++\xi^{++} into same-sign dileptons are fixed by the neutrino mass matrix. Observation of μe\mu-e conversion in nuclei is predicted.Comment: A comment on Tevatron reach and two references added. Discussion and conclusions unchange

    Auto and cross correlation of phases of the whole-sky CMB and foreground maps from the 1-year WMAP data

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    The issue of non-Gaussianity is not only related to distinguishing the theories of the origin of primordial fluctuations, but also crucial for the determination of cosmological parameters in the framework of inflation paradigm. We present an advenced method for testing non-Gaussianity on the whole-sky CMB anisotropies. This method is based on the Kuiper's statistic to probe the two-dimensional uniformity on a periodic mapping square associating phases: return mapping of phases of the derived CMB (similar to auto correlation) and cross correlations between phases of the derived CMB and foregrounds. Since phases reflect morphology, detection of cross correlation of phases signifies the contamination of foreground signals in the derived CMB map. The advantage of this method is that one can cross check the auto and cross correlation of phases of the derived CMB and foregrounds, and mark off those multipoles in which the non-Gaussianity results from the foreground contaminations. We apply this statistic on the derived signals from the 1-year WMAP data. The auto-correlations of phases from the ILC map shows the significance above 95% CL against the random phase hypothesis on 17 spherical harmonic multipoles, among which some have pronounced cross correlations with the foreground maps. We conclude that most of the non-Gaussianity found in the derived CMB maps are from foreground contaminations, except, among others, l=6. With this method we are better equipped to approach the issue of non-Gaussianity of primordial origin for the upcoming PLANCK mission.Comment: 2 figures added: new representation of reconstructed (from 1D Fourier composition) DT distribution for each multipole number el
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