2,027 research outputs found

    Fuzzy Inference System for VOLT/VAR control in distribution substations in isolated power systems

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    This paper presents a fuzzy inference system for voltage/reactive power control in distribution substations. The purpose is go forward to automation distribution and its implementation in isolated power systems where control capabilities are limited and it is common using the same applications as in continental power systems. This means that lot of functionalities do not apply and computational burden generates high response times. A fuzzy controller, with logic guidelines embedded based upon heuristic rules resulting from operators at dispatch control center past experience, has been designed. Working as an on-line tool, it has been tested under real conditions and it has managed the operation during a whole day in a distribution substation. Within the limits of control capabilities of the system, the controller maintained successfully an acceptable voltage profile, power factor values over 0,98 and it has ostensibly improved the performance given by an optimal power flow based automation system

    Highlights and Conclusions of the Chalonge 14th Paris Cosmology Colloquium 2010: `The Standard Model of the Universe: Theory and Observations'

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    The Chalonge 14th Paris Cosmology Colloquium was held on 22-24 July 2010 in Paris Observatory on the Standard Model of the Universe: News from WMAP7, BICEP, QUAD, SPT, AMI, ACT, Planck, QUIJOTE and Herschel; dark matter (DM) searches and galactic observations; related theory and simulations. %aiming synthesis, progress and clarification. P Biermann, D Boyanovsky, A Cooray, C Destri, H de Vega, G Gilmore, S Gottlober, E Komatsu, S McGaugh, A Lasenby, R Rebolo, P Salucci, N Sanchez and A Tikhonov present here their highlights of the Colloquium. Inflection points emerged: LambdaWDM (Warm DM) emerges impressively over LambdaCDM whose galactic scale problems are ever-increasing. Summary and conclusions by H. J. de Vega, M. C. Falvella and N. G. Sanchez stress among other points: (i) Primordial CMB gaussianity is confirmed. Inflation effective theory predicts a tensor to scalar ratio 0.05-0.04 at reach/border line of next CMB observations, early fast-roll inflation provides lowest multipoles depression. SZ amplitudes are smaller than expected: CMB and X-ray data agree but intracluster models need revision and relaxed/non-relaxed clusters distinction. (ii) cosmic ray positron excess is explained naturally by astrophysical processes, annihilating/decaying dark matter needs growing tailoring. (iii) Cored (non cusped) DM halos and warm (keV scale mass) DM are increasingly favored from theory and observations, naturally producing observed small scale structures, wimps turn strongly disfavoured. LambdaWDM 1 keV simulations well reproduce observations. Evidence that LambdaCDM does not work at small scales is staggering. P Biermann presents his live minutes of the Colloquium and concludes that a keV sterile neutrino is the most interesting DM candidate. Photos of the Colloquium are included.Comment: 58 pages, 20 figures. Three contributions added: G. Gilmore, S. Gottlober and E. Komats

    Towards the Chalonge 17th Paris Cosmology Colloquium 2013: highlights and conclusions of the Chalonge 16th Paris Cosmology Colloquium 2012

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    LWDM (Warm Dark Matter) is progressing impressively.The galactic scale crisis and decline of LCDM+baryons are staggering. The 16th Paris Chalonge Colloquium 2012 combined real cosmological/astrophysical data and hard theory predictive approach in the LWDM Standard Model. News and reviews from ACT,WMAP,SPT,QUIET,Planck,Herschel,JWST,UFFO,KATRIN and MARE experiments; astrophysics, particle and nuclear physics WDM searches, galactic observations, related theory and simulations, with the aim of synthesis and clarification. Here highlights by P Biermann, C Burigana, C Conselice, A Cooray, H de Vega, C Giunti & M Laveder, J Kormendi & K Freeman, E Ma, J Mather, L Page, G Smoot, N Sanchez. Summary and conclusions by de Vega, Falvella and Sanchez. Data confirm primordial CMB gaussianity. Effective (Ginsburg-Landau) Inflation theory predicts r about 0.04-0.05, negligeable running of ns, the inflation energy scale (GUT scale) and the set of CMB observables in agreement with the data. WMAP9 and Planck measurements are compatible with one or two Majorana sterile neutrinos in the eV mass scale. Cored (non cusped) DM halos and keV WDM are strongly favored by theory and observations, Wimps are strongly disfavoured. LambdaCDM with baryons do not work at small scales. Inside galaxy cores, quantum WDM effects are important. Quantum WDM calculations (Thomas-Fermi) provide galaxy masses, velocity dispersions and cored profiles and their sizes in agreement with observations. A WDM fermion of about 2 keV naturally reproduces galaxy, large scale and cosmological observations. WDM keV particles deserve dedicated astronomical and laboratory searches, theoretical work and numerical simulations. KATRIN can be adapted to look to keV scale sterile neutrinos. It will be a fantastic discovery to detect dark matter in beta decay. Photos of the Colloquium are includedComment: 58 pages, 15 figures. arXiv admin note: substantial text overlap with arXiv:1203.3562, arXiv:1305.7452, arXiv:1009.3494, arXiv:1304.075

    Towards the Chalonge 16th Paris Cosmology Colloquium 2012: Highlights and Conclusions of the Chalonge 15th Paris Cosmology Colloquium 2011

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    The Chalonge 15th Paris Cosmology Colloquium 2011 was held on 20-22 July in the historic Paris Observatory's Perrault building, in the Chalonge School spirit combining real cosmological/astrophysical data and hard theory predictive approach connected to them in the Warm Dark Matter Standard Model of the Universe: News and reviews from Herschel, QUIET, Atacama Cosmology Telescope (ACT), South Pole Telescole (SPT), Planck, PIXIE, the JWST, UFFO, KATRIN and MARE experiments; astrophysics, particle and nuclear physics warm dark matter (DM) searches and galactic observations, related theory and simulations, with the aim of synthesis, progress and clarification. Philippe Andre, Peter Biermann, Pasquale Blasi, Daniel Boyanovsky, Carlo Burigana, Hector de Vega, Joanna Dunkley, Gerry Gilmore, Alexander Kashlinsky, Alan Kogut, Anthony Lasenby, John Mather, Norma Sanchez, Alexei Smirnov, Sylvaine Turck-Chieze present here their highlights of the Colloquium. Ayuki Kamada and Sinziana Paduroiu present here their poster highlights. LambdaWDM (Warm Dark Matter) is progressing impressively over LambdaCDM whose galactic scale crisis and decline are staggering. The International School Daniel Chalonge issued an statement of strong support to the James Webb Space Telescope (JSWT). The Daniel Chalonge Medal 2011 was awarded to John C. Mather, Science PI of the JWST. Summary and conclusions are presented by H. J. de Vega, M. C. Falvella and N. G. Sanchez. Overall, LambdaWDM and keV scale DM particles deserve dedicated astronomical and laboratory experimental searches, theoretical work and simulations. KATRIN experiment in the future could perhaps adapt its set-up to look to keV scale sterile neutrinos. It will be a a fantastic discovery to detect dark matter in a beta decay. Photos of the Colloquium are included. (Abridged)Comment: 65 pages, 21 figure

    On the difference between proton and neutron spin-orbit splittings in nuclei

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    The latest experimental data on nuclei at 132^{132}Sn permit us for the first time to determine the spin-orbit splittings of neutrons and protons in identical orbits in this neutron-rich doubly-magic region and compare the case to that of 208^{208}Pb. Using the new results, which are now consistent for the two neutron-rich doubly magic regions, a theoretical analysis defines the isotopic dependence of the mean field spin-orbit potential and leads to a simple explicit expression for the difference between the spin-orbit splittings of neutrons and protons. The isotopic dependence is explained in the framework of different theoretical approaches.Comment: 8 pages, revte

    String Tension and the Generation of the Conformal Anomaly

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    The origin of the string conformal anomaly is studied in detail. We use a reformulated string Lagrangian which allows to consider the string tension T0T_{0} as a small perturbation. The expansion parameter is the worldsheet speed of light c, which is proportional to T0T_{0} . We examine carefully the interplay between a null (tensionless) string and a tensionful string which includes orders c2 c^{2} and higher. The conformal algebra generated by the constraints is considered. At the quantum level the normal ordering provides a central charge proportional to c2 c^{2} . Thus it is clear that quantum null strings respect conformal invariance and it is the string tension which generates the conformal anomaly.Comment: More references are included. Final version, to appear in Phys.Rev.D. 6 pages, LaTex, no figure

    String propagation in four-dimensional dyonic black hole background

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    We study string propagation in an exact, four-dimensional dyonic black hole background. The general solutions describing string configurations are obtained by solving the string equations of motion and constraints. By using the covariant formalism, we also investigate the propagation of physical perturbations along the string in the given curved background.Comment: 19 pages, Tex (macro phyzzx is needed

    Advances in String Theory in Curved Backgrounds: A Synthesis Report

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    A synthetic report of the advances in the study of classical and quantum string dynamics in curved backgrounds is provided, namely: the new feature of multistring solutions; the effect of a cosmological constant and of spacial curvature on classical and quantum strings; classical splitting of fundamental strings;the general string evolution in constant curvature spacetimes;the conformal invariant effects;strings on plane waves, shock waves and spacetime singularities and its spectrum. New developments in string gravity and string cosmology are reported: string driven cosmology and its predictions;the primordial gravitation wave background; non-singular string cosmologies from exact conformal field theories;QFT, string temperature and the string phase of de Sitter space; the string phase of black holes;new dual relation between QFT regimes and string regimes and the 'QFT/String Tango'; new coherent string states and minimal uncertainty principle in string theor

    Spin-1/2 "bosons" with mass dimension 3/2 and fermions with mass dimension 1 cannot represent physical particle states

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    We delve into the first principles of quantum field theory to prove that the so-called spin-1/2 "bosons" and the fermions with mass dimension 1, including ELKO, cannot represent physical particle states with spin 1/2. Specifically, we first demonstrate that both aforementioned fields are not invariant under rotational symmetry, which implies that the particles created for these fields are not eigenstates of the spin operator in the (1/2, 0) circle plus (0, 1/2) representation of the Lorentz group, nor is it possible to construct a Hamiltonian density scalar under the rotational group from them. Furthermore, following Weinberg's approach to local causal fields, we prove that regardless of any discrete symmetry or adjoint structure, the relativistic fields in the (1/2, 0) circle plus (0, 1/2) representation satisfy the Fermi-Dirac statistics in complete agreement with the well-established spin-statistics theorem and experimental results.Peer reviewe

    Role of Sterile Neutrino Warm Dark Matter in Rhenium and Tritium Beta Decays

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    Sterile neutrinos with mass in the range of one to a few keV are important as extensions of the Standard Model of particle physics and are serious dark matter (DM) candidates. This DM mass scale (warm DM) is in agreement with both cosmological and galactic observations. We study the role of a keV sterile neutrino through its mixing with a light active neutrino in Rhenium 187 and Tritium beta decays. We pinpoint the energy spectrum of the beta particle, 0 < T_e < (Q_{beta} - m_s), as the region where a sterile neutrino could be detected and where its mass m_s could be measured. This energy region is at least 1 keV away rom the region suitable to measure the mass of the light active neutrino, located near the endpoint Q_{beta} . The emission of a keV sterile neutrino in a beta decay could show up as a small kink in the spectrum of the emitted beta particle. With this in view, we perform a careful calculation of the Rhenium and Tritium beta spectra and estimate the size of this perturbation by means of the dimensionless ratio R of the sterile neutrino to the active neutrino contributions. We comment on the possibility of searching for sterile neutrino signatures in two experiments which are currently running at present, MARE and KATRIN, focused on the Rhenium 187 and Tritium beta decays respectively.Comment: 16 pages, 10 figures. Version to appear in Nucl. Phys. B. Results and conclusions unchange
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