90 research outputs found

    Ultrathin Tropical Tropopause Clouds (UTTCs) : I. Cloud morphology and occurrence

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    Subvisible cirrus clouds (SVCs) may contribute to dehydration close to the tropical tropopause. The higher and colder SVCs and the larger their ice crystals, the more likely they represent the last efficient point of contact of the gas phase with the ice phase and, hence, the last dehydrating step, before the air enters the stratosphere. The first simultaneous in situ and remote sensing measurements of SVCs were taken during the APE-THESEO campaign in the western Indian ocean in February/March 1999. The observed clouds, termed Ultrathin Tropical Tropopause Clouds (UTTCs), belong to the geometrically and optically thinnest large-scale clouds in the Earth´s atmosphere. Individual UTTCs may exist for many hours as an only 200--300 m thick cloud layer just a few hundred meters below the tropical cold point tropopause, covering up to 105 km2. With temperatures as low as 181 K these clouds are prime representatives for defining the water mixing ratio of air entering the lower stratosphere

    Novel implementation of the INFN-CHNet X-ray fluorescence scanner for the study of ancient photographs, archaeological pottery, and rock art

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    INFN-CHNet is the cultural heritage network of the Italian National Institute of Nuclear Physics (INFN) and is constituted by units from Italy and from outside Europe, one of them at Universidad Nacional de San Martín (UNSAM) in Buenos Aires, Argentina. As a result of the initiative carried out during 2015 by the Accademia dei Lincei for the year of the Italian culture in Latin America, an INFN-CHNet laboratory was set at CEPyA-UNSAM with the collaboration of INFN and the Restoration Workshop Centro Tarea. Noteworthy, this laboratory is conceived as a multidisciplinary research facility with complementary skills, both scientific and humanistic. In this context, the first instrument jointly set up, optimised, and applied to Cultural Heritage was an X-ray fluorescence scanner. In this manuscript, we describe the instrument and its main features together with a set of representative yet novel applications in the field of cultural heritage, namely, the experimental study of hidden rock art through laboratory replicas that imitates the problems found in the archaeological sites (hematite drawings hidden below carbon deposition); the study and chemical characterisation of archaeological decorated pottery; and finally, the application of the XRF scanner to ancient photography, for quick and accurate identification of materials and techniques employed. Beyond these specific results, the primary output of this initiative has been the conception of a future network of scientific laboratories in South America, coordinated by CEPyA at UNSAM.Fil: Taccetti, F.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Castelli, L.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Czelusniak, C.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Giambi, F.. Istituto Nazionale di Fisica Nucleare; Italia. Università degli Studi di Firenze; ItaliaFil: Manetti, M.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Massi, M.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Mazzinghi, A.. Istituto Nazionale di Fisica Nucleare; Italia. Università degli Studi di Firenze; ItaliaFil: Ruberto, C.. Istituto Nazionale di Fisica Nucleare; Italia. Università degli Studi di Firenze; ItaliaFil: Arneodo, F.. New York University Abu Dhabi; Emiratos Arabes UnidosFil: Torres, R.. Università degli Studi di Firenze; Italia. New York University Abu Dhabi; Emiratos Arabes UnidosFil: Castellá, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Instituto de Investigaciones sobre el Patrimonio Cultural; ArgentinaFil: Gheco, Lucas Ignacio. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Catamarca. Universidad Nacional de Catamarca. Centro de Investigaciones y Transferencia de Catamarca; ArgentinaFil: Mastrangelo, Noemi Elisa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto de Investigacion E Ingenieria Ambiental (ehys-unsam) ; Escuela de Hábitat y Sostenibilidad ; Universidad Nacional de San Martin;Fil: Gallegos, D.. Universidad Nacional de San Martín; ArgentinaFil: Morales, A.. Universidad Nacional de San Martín; ArgentinaFil: Tascon, Marcos. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Marte, F.. Universidad Nacional de San Martín; ArgentinaFil: Giuntini, L.. Università degli Studi di Firenze; Italia. Istituto Nazionale di Fisica Nucleare; Itali
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