926 research outputs found

    In Situ Calibration of Heterogeneous Acquisition Systems: The Monitoring System of a Photovoltaic Plant

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    This paper deals with the metrological management of an acquisition system that has been developed for monitoring an experimental photovoltaic (PV) plant. The acquisition system has been conceived for comparing the performance of different PV technologies and for verifying the nominal specifications of the PV modules. For these reasons, the traceability of the monitoring system has to be ensured, and therefore, it must be periodically calibrated. A remotely exercised procedure is proposed for the calibration of the acquisition system, which is based on a calibrator specifically designed for this application. This calibrator has the capability to act as a reference for heterogeneous quantities, including electrical quantities, temperature, and solar irradiance. The architecture of this calibrator is described, and experimental results for the preliminary characterization of the prototype are described

    The magnetic field topology associated to two M flares

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    On 27 October, 2003, two GOES M-class flares occurred in the lapse of three hours in active region NOAA 10486. The two flares were confined and their associated brightenings appeared at the same location, displaying a very similar shape both at the chromospheric and coronal levels. We focus on the analysis of magnetic field (SOHO/MDI), chromospheric (HASTA, Kanzelhoehe Solar Observatory, TRACE) and coronal (TRACE) observations. By combining our data analysis with a model of the coronal magnetic field, we compute the magnetic field topology associated to the two M flares. We find that both events can be explained in terms of a localized magnetic reconnection process occurring at a coronal magnetic null point. This null point is also present at the same location one day later, on 28 October, 2003. Magnetic energy release at this null point was proposed as the origin of a localized event that occurred independently with a large X17 flare on 28 October, 2003, at 11:01 UT. The three events, those on 27 October and the one on 28 October, are homologous. Our results show that coronal null points can be stable topological structures where energy release via magnetic reconnection can happen, as proposed by classical magnetic reconnection models.Comment: 14 pages, 7 figure

    Hα Moreton waves observed on December 06, 2006: A 2D case study

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    Context. We present high temporal resolution observations of a Moreton wave event detected with the Hα Solar Telescope for Argentina (HASTA) in the Hα line 656.3 nm, on December 6, 2006. Aims. The aim is to contribute to the discussion about the nature and triggering mechanisms of Moreton wave events. Methods. We describe the HASTA telescope capabilities and the observational techniques. We carried out a detailed analysis to determine the flare onset, the radiant point location, the kinematics of the disturbance and the activation time of two distant filaments. We used a 2D reconstruction of the HASTA and corresponding TRACE observations, together with conventional techniques, to analyze the probable origin of the phenomenon. Results. The kinematic parameters and the probable onset time of the Moreton wave event are determined. A small-scale ejectum and the winking of two remote filaments are analyzed to discuss their relation with the Moreton disturbance. Conclusions. The analysis of the Moreton wave event favors the hypothesis that the phenomenon can be described as the chromospheric imprint of a single fast coronal shock triggered from a single source in association with a coronal mass ejection. Its onset time is concurrent with a Lorentz force peak measured in the photosphere, as stated by other authors. However, the existence of multiple shock waves that were generated almost simultaneously cannot be discarded.Fil: Francile, Carlos Natale. Universidad Nacional de San Juan. Facultad de Cs.exactas Fisicas y Naturales. Departamento de Informatica. Observat.astron. Felix Aguilar;Fil: Costa, Andrea. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Cordoba. Instituto de Astronomia Teorica y Experimental;Fil: Luoni, Maria Luisa. Consejo Nacional de Invest.cientif.y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Astronomia y Fisica del Espacio(i);Fil: Elaskar, Sergio Amado. Universidad Nacional de Cordoba. Facultad de Cs.exactas Fisicas y Naturales

    Generalised models for torsional spine and fan magnetic reconnection

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    Three-dimensional null points are present in abundance in the solar corona, and the same is likely to be true in other astrophysical environments. Recent studies suggest that reconnection at such 3D nulls may play an important role in the coronal dynamics. In this paper the properties of the torsional spine and torsional fan modes of magnetic reconnection at 3D nulls are investigated. New analytical models are developed, which for the first time include a current layer that is spatially localised around the null, extending along either the spine or the fan of the null. These are complemented with numerical simulations. The principal aim is to investigate the effect of varying the degree of asymmetry of the null point magnetic field on the resulting reconnection process - where previous studies always considered a non-generic radially symmetric null. The geometry of the current layers within which torsional spine and torsional fan reconnection occur is found to be strongly dependent on the symmetry of the magnetic field. Torsional spine reconnection still occurs in a narrow tube around the spine, but with elliptical cross-section when the fan eigenvalues are different, and with the short axis of the ellipse being along the strong field direction. The spatiotemporal peak current, and the peak reconnection rate attained, are found not to depend strongly on the degree of asymmetry. For torsional fan reconnection, the reconnection occurs in a planar disk in the fan surface, which is again elliptical when the symmetry of the magnetic field is broken. The short axis of the ellipse is along the weak field direction, with the current being peaked in these weak field regions. The peak current and peak reconnection rate in this case are clearly dependent on the asymmetry, with the peak current increasing but the reconnection rate decreasing as the degree of asymmetry is increased

    Parent and self-report health-related quality of life measures in young patients with Tourette syndrome

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    Tourette syndrome is a neurodevelopmental disorder characterized by tics and comorbid behavioral problems. This study compared child- and parent-reported quality of life and everyday functioning. We assessed 75 children with Tourette syndrome, of which 42 (56%) had comorbid conditions (obsessive-compulsive disorder = 25; attention-deficit hyperactivity disorder = 6; both comorbidities = 4). All patients completed psychometric instruments, including the Gilles de la Tourette Syndrome-Quality of Life Scale for Children and Adolescents (child report) and the Child Tourette's Syndrome Impairment Scale (parent report). Data were compared for patients with pure Tourette syndrome, Tourette syndrome + obsessive-compulsive disorder, Tourette syndrome + attention-deficit hyperactivity disorder, and Tourette syndrome + both comorbidities. There were no group differences in quality of life. However, there were differences for total, school, and home activities impairment scores. Children and parents may not share similar views about the impact of Tourette syndrome on functioning. The measurement of health-related quality of life in Tourette syndrome is more complex in children than adults

    Long-term chromospheric activity in southern M dwarfs: Gl 229 A and Gl 752 A

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    Several late-type stars present activity cycles similar to that of the Sun. However, these cycles have been mostly studied in F to K stars. Due to their small intrinsic brightness, M dwarfs are not usually the targets of long-term observational studies of stellar activity, and their long-term variability is generally not known. In this work, we study the long-term activity of two M dwarf stars: Gl 229 A (M1/2) and Gl 752 A (M2.5). We employ medium resolution echelle spectra obtained at the 2.15 m telescope at the Argentinian observatory CASLEO between the years 2000 and 2010 and photometric observations obtained from the ASAS database. We analyzed Ca \II K line-core fluxes and the mean V magnitude with the Lomb-Scargle periodogram, and we obtain possible activity cycles of \sim4 yr and \sim7 yr for Gl 229 A and Gl 752 A respectively.Comment: Accepted for publication by Astronomical Journal (AJ

    INFORM scientific and technical improvements in 2017: Missing values imputation and IT developments

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    The JRC is the technical and scientific leader of the INFORM model, and responsible for methodological improvements, and their implementation. This publication describe the INFORM methodological and technical improvements implemented by JRC in the 2017. On despite the indicators have been selected on be base of their reliability, consistency continuity and completeness, most of the them don’t cover all the countries for all the year. This results in a significant number of missing values, irregularly distributed among countries, time and indicators. This report describes an innovative approach for predicting missing values using advanced statistical technics. We also present the IT developments in support to the INFORM model, including the web platform for managing the INFORM Subnational models and the improvements in the API.JRC.E.1-Disaster Risk Managemen

    Observed flux density enhancement at submillimeter wavelengths during an X-class flare

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    We analyse the 30 October, 2004, X1.2/SF solar event that occurred in AR 10691 (N13 W18) at around 11:44 UT. Observations at 212 and 405 GHz of the Solar Submillimeter Telescope (SST), with high time resolution (5 ms), show an intense impulsive burst followed by a long-lasting thermal phase. EUV images from the Extreme Ultraviolet Imaging Telescope (SOHO/EIT) are used to identify the possible emitting sources. Data from the Radio Solar Telescope Network (RSTN) complement our spectral observations below 15 GHz. During the impulsive phase the turnover frequency is above 15.4 GHz. The long-lasting phase is analysed in terms of thermal emission and compared with GOES observations. From the ratio between the two GOES soft X-ray bands, we derive the temperature and emission measure, which is used to estimate the free-free submillimeter flux density. Good temporal agreement is found between the estimated and observed profiles, however the former is larger than the latter.Comment: 13 pages, 7 figure

    Comparison of 30 THz impulsive burst time development to microwaves, H-alpha, EUV, and GOES soft X-rays

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    The recent discovery of impulsive solar burst emission in the 30 THz band is raising new interpretation challenges. One event associated with a GOES M2 class flare has been observed simultaneously in microwaves, H-alpha, EUV, and soft X-ray bands. Although these new observations confirm some features found in the two prior known events, they exhibit time profile structure discrepancies between 30 THz, microwaves, and hard X-rays (as inferred from the Neupert effect). These results suggest a more complex relationship between 30 THz emission and radiation produced at other wavelength ranges. The multiple frequency emissions in the impulsive phase are likely to be produced at a common flaring site lower in the chromosphere. The 30 THz burst emission may be either part of a nonthermal radiation mechanism or due to the rapid thermal response to a beam of high-energy particles bombarding the dense solar atmosphere.Comment: accepted to Astronomy and Astrophysic

    Building Smarter Infrastructure:: Resource Productivity in a Residential Development for Steinhatchee, Florida

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    Environmental reforms in America have developed a significant repertoire of conservation practices directly proportional to the boom in suburban development since World War II. The chief obstacle to past comprehensive reforms in land development has been the fragmented approach of individual conservation practices, as their particular science and application were developed independently of one another. The following is a case study in design for The Conservancy, a "green development” for a 56-unit rural residential community on the Gulf of Mexico. The goal of design and research is to recombine environmental technologies in planning, infrastructure, landscape architecture, and architecture towards more integrated community development. Design methodologies are implemented to address three conservation criteria common to all green economy business models. First is advanced resource productivity to ease the energy economy's reliance on nonrenewable resources. Infrastructural logics, otherwise isolated in conventional development, are bundled into a mosaic with new operational overlaps. Second is the creation of closed-loop energy systems that promote the recycling of energy and materials to eliminate waste. Building and site utility systems are modeled after "feedback” in biological systems. Third is the responsible stewardship of existing resources that harness the ecology to create sustainable land use configurations. Landscape and architecture are integrated into a unified planning module as biological systems serve urbanizing functions. Since the lack of integrative thinking has been the obstacle to sustainable land development, recombinant design modalities, such as those used in The Conservancy, rather than technological innovation, will play the more critical role in developing sustainable environments
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