22,234 research outputs found

    Web based system architecture for long pulse remote experimentation

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    Remote experimentation (RE) methods will be essential in next generation fusion devices. Requirements for long pulse RE will be: on-line data visualization, on-line data acquisition processes monitoring and on-line data acquisition systems interactions (start, stop or set-up modifications). Note that these methods are not oriented to real-time control of fusion plant devices. INDRA Sistemas S.A., CIEMAT (Centro de Investigaciones Energéticas Medioambientales y Tecnológicas) and UPM (Universidad Politécnica de Madrid) have designed a specific software architecture for these purposes. The architecture can be supported on the BeansNet platform, whose integration with an application server provides an adequate solution to the requirements. BeansNet is a JINI based framework developed by INDRA, which makes easy the implementation of a remote experimentation model based on a Service Oriented Architecture. The new software architecture has been designed on the basis of the experience acquired in the development of an upgrade of the TJ-II remote experimentation system

    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

    Nuclear physics in soft-wall AdS/QCD: Deuteron electromagnetic form factors

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    We present a high-quality description of the deuteron electromagnetic form factors in a soft-wall AdS/QCD approach. We first propose an effective action describing the dynamics of the deuteron in the presence of an external vector field. Based on this action the deuteron electromagnetic form factors are calculated, displaying the correct 1/Q^10 power scaling for large Q^2 values. This finding is consistent with quark counting rules and the earlier observation that this result holds in confining gauge/gravity duals. The Q^2 dependence of the deuteron form factors is defined by a single and universal scale parameter kappa, which is fixed from data.Comment: 6 page

    Nucleon resonances in AdS/QCD

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    We describe the electroproduction of the N(1440) Roper resonance in soft-wall AdS/QCD. The Roper resonance is identified as the first radially excited state of the nucleon, where higher-Fock states in addition to the three-quark component are included. The main conclusion is that the leading 3q component plays the dominant role in the description of electroproduction properties of this resonance: form factors, helicity amplitudes and charge densities. The obtained results are in good agreement with the recent results of the CLAS Collaboration at JLab.Comment: 20 pages. arXiv admin note: text overlap with arXiv:1204.661

    Data reduction in the ITMS system through a data acquisition model with self-adaptive sampling rate

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    Long pulse or steady state operation of fusion experiments require data acquisition and processing systems that reduce the volume of data involved. The availability of self-adaptive sampling rate systems and the use of real-time lossless data compression techniques can help solve these problems. The former is important for continuous adaptation of sampling frequency for experimental requirements. The latter allows the maintenance of continuous digitization under limited memory conditions. This can be achieved by permanent transmission of compressed data to other systems. The compacted transfer ensures the use of minimum bandwidth. This paper presents an implementation based on intelligent test and measurement system (ITMS), a data acquisition system architecture with multiprocessing capabilities that permits it to adapt the system’s sampling frequency throughout the experiment. The sampling rate can be controlled depending on the experiment’s specific requirements by using an external dc voltage signal or by defining user events through software. The system takes advantage of the high processing capabilities of the ITMS platform to implement a data reduction mechanism based in lossless data compression algorithms which are themselves based in periodic deltas

    Mapping the galaxy NGC 4486 (M87) through its Globular Cluster System

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    As shown in previous works, globular clusters can be used to trace the overall structure of the diffuse stellar populations in early type galaxies if the number of clusters per unit stellar mass depends on metallicity. In this paper we further test this assumption in the galaxy NGC 4486 (M 87), by combining several data sources. The results show that globular clusters allow the mapping of the galaxy in terms of the surface brightness profile, integrated colour gradient, chemical abundance, and mass to luminosity ratios up to 1000 arcsec (or 80.4 kpc) from its centre (i.e. some 10 effective radii). The analysis indicates the presence of a dominant high metallicity bulge associated with the red globulars, whose ellipticity increases outwards, and of a more flattened low metallicity halo connected with the blue globulars. The chemical abundance gradient of the composite stellar population is remarkably similar to that inferred from X ray observations of hot gas. The mass-metallicity spectrum of the stellar population can, in principle, be understood in terms of inhomogeneous enrichment models. In turn, the distribution of the bluest GCs, and lowest metallicity halo stars, has an intriguing similarity with that of dark matter, a feature shared with NGC 1399. Also, in these two galaxies, the number of blue GCs per dark mass unit is identical within the errors, \approx 1.0(\pm0.3) \times 10^{-9} . The total stellar mass derived for NGC 4486 is 6.8(\pm1.1) \times 10^{11} M\odot with a baryonic mass fraction fb = 0.08(\pm 0.01).Comment: 18 pages, 23 figure
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