Le città e l'Europa

L’elaborazione dell’Agenda Urbana Europea ha, insieme all’Agenda Urbana Nazionale dei Paesi dell’Unione, lo scopo di integrare le strategie dei diversi territori ed accrescere il dinamismo economico. Laddove manchi la sinergia fra tali livelli operativi diminuisce la potenzialità e l’efficacia delle politiche urbane. Da una riflessione critica sul flop della candidatura della città di Palermo al titolo di Capitale Europea della Cultura è possibile estrapolare spunti per una buona costruzione di politiche urbane nell'ambito di un'Agenda Urbana Nazionale e per progetti competitivi nei cicli di programmazione europea.

Graphene oxide and Fumed silica graphene oxide nanocomposites modification by thermal treatments

In the present study we investigate post synthesis thermal treatments up to 400 °C of graphene oxide (GrO) prepared from commercial graphite and of GrO–silica nanocomposites prepared by a solution of commercial Fumed silica nanoparticles (average diameter 7 nm or 40 nm) and the GrO. The thermal treatments were carried out in air, vacuum or He atmosphere to highlight tunable changes. Two GrO batches with small differences in the D (~1350 cm–1) and G (~1580 cm–1) Raman bands have been employed to evaluate effects depending on preparation. Thermal effects have been monitored through the Raman spectroscopy focusing on D, G and 2D (2500–3500 cm–1) bands spectral ranges. The experiments evidenced…

Inhomogeneity Effects On Point Defects Studied By Photoluminescence Time Decay In SiO2.

X-ray irradiation effects on a specific multistep Ge-doped fiber

International audience; The study of point defects generation in optical fibers plays an important role with regards to their use and application in different domains. Their design and elaboration processes (dopants type, concentration, refractive index profile, drawing conditions...) govern their responses and more generally their radiation hardness [1]. In this work we investigated, the influence of 10 keV X-ray irradiations on a set of specific germanosilicate optical fibers elaborated from the same preform at different drawing conditions. The germanium doping levels along the fiber core diameter was specifically designed to follow a two-step distribution in order to highlight the Ge-con…

Influence of fluorine on the fiber performance studied through the NBOHC-related 1.9 eV microluminescence

International audience; The distribution of Non Bridging Oxygen Hole Centers (NBOHC) in Fluorine doped optical fibers was investigated by confocal microluminescence spectroscopy monitoring the characteristic 1.9 eV luminescence band. The results show that these defects are generated by the fiber drawing and their concentration further increases after γ irradiation. The NBOHC profile along the fiber is anticorrelated to the fluorine content. This finding agrees with the role of fluorine in the fiber toughness and is discussed from the microscopic point of view on the basis of previous works.

Radiation Response of Ce-Doped Phosphosilicate Optical Fibers

International audience; We report an experimental study of the radiation effects on silica-based multimode optical fibers (OFs) either doped with Phosphorus or with Phosphorus and Cerium. Online Radiation-Induced-Absorption (RIA) measurements were performed in the UV-visible spectral domain under 10 keV X-ray Irradiation. Optical Absorption (OA) in the Near Infrared Region (NIR) and Electron Paramagnetic Resonance (EPR) measurements were also performed on γ-irradiated OFs.