580 research outputs found

    GlobVolcano Project Overview

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    The GlobVolcano project is part of the ESA DUE programme. The project aims at demonstrating EO-based services to support the Volcanological Observatories and other mandate users (e.g. Civil Protection authorities, scientific communities of volcanoes) in their monitoring activities. During the project a worldwide selection of user organizations will cooperate with the GlobVolcano team in order to harmonize user’s requirements and to evaluate the EO-based services . The “Osservatorio Vesuviano” of Naples (INGV-Italy) coordinates the communications between the project and the User Community. IPGP of Paris is responsible for the scientific coordination and the validation activities. The project activities are split in two phases. During the first phase (completed in June 2008) the service infrastructure and interface to the users have been developed. Prototype EO-based information products have been generated and validated. Service provision on pre-operational basis will take place during the second phase

    Improving monitoring techniques by exploiting TerraSAR-X data: an application to Campi Flegrei (Naples, Italy)

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    Geodetic monitoring of the Neapolitan Volcanic District, including the Campi Flegrei caldera on the west of the city of Naples (Italy), is carried out via an integration between ground based networks and space-borne DInSAR techniques, exploiting the SAR sensors onboard ERS1-2 and ENVISAT satellites. This allowed, for instance, to follow the time evolution of the small uplift events which took place in 2000 and 2005-2006. Unfortunately, the use of the ENVISAT C-band could result sometimes in no information when dealing with very low deformation rates, as in the 2005-2006 case, when only continuous ground stations were able to detect the very beginning of the uplift event. To overcome this problem, from December 2009 we decided to use an high resolution SAR sensor operating in the X band, i.e. TerraSAR-X from DLR. TerraSAR-X High Resolution Spotlight scenes covering the main part of the Campi Flegrei caldera and centred on the Solfatara crater were used for a DInSAR analysis, using the GENESIS DLR’s software. The first two scenes (Dec. 15 and 26) were acquired with a temporal baseline of only one repetition cycle (11 days) and formed an interferogram with a very small perpendicular baseline (16.5 m). Apart from some minor atmospheric effects, the interferogram shows a small but clear deformation signal in the Pisciarelli area, close to the east side of the Solfatara crater. The ellipse shaped uplift area extends approximately 30 meters in E-W and 20 meters in N-S directions and the maximum deformation is up to 10 mm in the centre of the uplifted area. The availability of a new scene (06/01/2010) allowed three possible combinations. The deformation event highlighted by this analysis is consistent with geochemical observations carried out in Pisciarelli by INGV-OV. Pisciarelli area is seat of a fumarolic field systematically monitored in the frame of the volcanic surveillance of the Campi Flegrei caldera. Two field surveys highlighted that, during the period of SAR images acquisition, a new and strong fumarolic vent appeared in the centre of the uplifted area. In fact the vent, firstly observed on Dec. 21, was absent on Dec. 16. The two independent observations, field surveys and SAR data, suggest that the opening of the fumarolic vent was preceded by the pressurization of a small part of the fumarolic field highlighted by the documented uplift. The correlation between the dynamics of the fumarolic field and the deformation signal is confirmed by the fact that in the 26/12/2009-06/01/2010 interferogram the deformation signal is no more detectable. Finally, this case proves the high potentiality of TerraSAR-X High Resolution Spotlight data in monitoring volcanic activity with a resolution suitable for detecting also minor, but possibly dangerous, changes of the systems, as it could be in the early recognition of the signals generated by impending phreatic eruptions. TerraSAR-X High Resolution Spotlight acquisitions will continue every cycle and PS-InSAR and SBAS algorithms will be applied to carefully monitor any further changes in the activity of the Campi Flegrei volcanic system

    Connecting urban and regional socio-ecological transitions: Paths to a non fossil society in the Swedish Stockholm-Mälar area

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    Introduction: The embedding of cities in a wider regional frame is central for long term planning regarding the transformation of such parts of society. This holds especially true for urban centers of national or sub national status. In this presentation we are drawing on 4 years of research work and stakeholder consultations in the Swedish part of the EU COMPLEX project dealing with the transition to non fossil societies. In our presentation the regional multi layered governance which encompasses both a large (the Swedish capital) city and its surrounding region with an archipelago of larger and smaller towns is at the heart of the presentation. Our core interest is in the transition to sustainable and resilient urban futures. Especially we are drawing on the experiences from the Swedish case in the EU project COMPLEX. Method: We are relying both on stakeholder consultations with regard to long term planning as well as on specific regional modelling efforts covering specific features as municipality planning, economic regional analysis, land use studies and cognitive analysis regarding decision making by individuals, Results: We have focused on the systemic interactions of many different kinds covering long term developments (up to 2050). Our focus is to analyze features of the transition process of our urban-region at large and the connected decision making features e.g. in terms of scenario elaborations. Discussion: We highlight the differences of opinions among a wide range of stakeholders with regard to their understanding of the issues, their ideological positioning about core matters of concerns and the various positions about appropriate paths for reaching the goals of the transition to a non-fossil urban super region situation in our chosen case area

    Tunable few electron quantum dots in InAs nanowires

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    Quantum dots realized in InAs are versatile systems to study the effect of spin-orbit interaction on the spin coherence, as well as the possibility to manipulate single spins using an electric field. We present transport measurements on quantum dots realized in InAs nanowires. Lithographically defined top-gates are used to locally deplete the nanowire and to form tunneling barriers. By using three gates, we can form either single quantum dots, or two quantum dots in series along the nanowire. Measurements of the stability diagrams for both cases show that this method is suitable for producing high quality quantum dots in InAs.Comment: 8 pages, 4 figure

    Bright single-photon sources in bottom-up tailored nanowires

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    The ability to achieve near-unity light extraction efficiency is necessary for a truly deterministic single photon source. The most promising method to reach such high efficiencies is based on embedding single photon emitters in tapered photonic waveguides defined by top-down etching techniques. However, light extraction efficiencies in current top-down approaches are limited by fabrication imperfections and etching induced defects. The efficiency is further tempered by randomly positioned off-axis quantum emitters. Here, we present perfectly positioned single quantum dots on the axis of a tailored nanowire waveguide using bottom-up growth. In comparison to quantum dots in nanowires without waveguide, we demonstrate a 24-fold enhancement in the single photon flux, corresponding to a light extraction efficiency of 42 %. Such high efficiencies in one-dimensional nanowires are promising to transfer quantum information over large distances between remote stationary qubits using flying qubits within the same nanowire p-n junction.Comment: 19 pages, 6 figure
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