3,804 research outputs found

    The Buprestidae (Coleoptera, Buprestoidea) of the Tuscan Archipelago (Italy)

    Get PDF
    Background Buprestidae is a group of beetles of important conservation and phytosanitary value that is poorly studied in the Tuscan Archipelago and the limited faunistic knowledge available refers to a few scant historical records. New information The present contribution increments the species documented in the Archipelago from 27 to 51, providing more than 300 georeferenced occurrence records, derived from both direct field research and citizen science via iNaturalist. Of particular importance is the discovery of Eurythyrea quercus on Isola d'Elba, an uncommon and localised species currently critically endangered

    The Frascati Beam Test Facility

    Full text link
    From 2004 the Frascati Beam Test Facility (BTF) in the DAFNE accelerator complex provides to the external user up to 1E10 electrons per bunch or up to 10E9 positrons per bunch to develop their detectors. After an upgrade program terminated in 2020 of the beam test facility a description of the status and available beam lines will be done.Comment: Talk presented at the International Workshop on Future Linear Colliders (LCWS 2023), 15-19 May 2023. C23-05-15.

    Performance of the PADME calorimeter prototype at the DAΦ\PhiNE BTF

    Full text link
    The PADME experiment at the DAΦ\PhiNE Beam-Test Facility (BTF) aims at searching for invisible decays of the dark photon by measuring the final state missing mass in the process e+e−→γ+A′e^+e^- \to \gamma+ A', with A′A' undetected. The measurement requires the determination of the 4-momentum of the recoil photon, performed using a homogeneous, highly segmented BGO crystals calorimeter. We report the results of the test of a 5×\times5 crystals prototype performed with an electron beam at the BTF in July 2016

    Geopolymer Materials for Low-Pressure Injections in Coarse Grained Soil: Multiscale Approach to the Study of the Mechanical Behaviour and Environmental Impact

    Get PDF
    The term soil improvement is commonly referred to the modification of soil structure in order to obtain a material with better physical and mechanical properties such as strength, stiffness or permeability. With this purpose, one of the most commonly used applications, particularly in coarse-grained soils, is the low pressure injection of cementitious mixtures. In recent years, there has been a growing demand for solutions with limited environmental impact and limited CO2 emissions and, in this regard, the cement present in the injected grout is evidently the weak point of traditional solutions. In this work, the experimental study of geopolymer materials as a substitute of cement mixture for low-pressure injection for coarse-grained soils improvement is presented. The study started with a focus on the geopolymer fresh mixture properties (density, viscosity, horizontal ellipsis ) and the evolution over the time of the mechanical properties (compression and tensile strength and stiffness) comparing three different mix designs at three different monitoring temperatures. The same evaluations were repeated on sand samples injected with the different types of mixtures previously analyzed. For a selected mix design, a permeation test was carried out under controlled conditions to test the pumpability and effectiveness of geopolymer injection. Finally, to deepen the chemical interaction between the injected mixture and interstitial water, an injection test was carried out using a scaled model of a real injection system. The experimental study carried out was aimed both at the analysis of the characteristics of the geopolymer material and at its physical interaction with coarse-grained soil, passing through the measurement of the mechanical characteristics of the geopolymer material and of the solid sand skeleton mixed with geopolymers. Finally, the possible chemical interaction of the mixtures with groundwater was also evaluated in order to highlight any environmental issues. The results shown provide a preliminary but sufficiently broad picture of the behavior of geopolymer mixtures for low-pressure injection for coarse-grained soil improvement purposes both from physical-mechanical and chemical points of view

    FEMIP: A high performance FPGA-based features extractor & matcher for space applications

    Get PDF
    Nowadays, Video-Based Navigation (VBN) is increasingly used in space-applications. The future space-missions will include this approach during the Entry, Descent and Landing (EDL) phase, in order to increase the landing point precision. This paper presents FEMIP: a high performance FPGA-based features extractor and matcher tuned for space applications. It outperforms the current state-of-the-art, ensuring a higher throughput and a lower hardware resources usage

    Performance of the diamond active target prototype for the PADME experiment at the DAΦ\PhiNE BTF

    Full text link
    The PADME experiment at the DAΦ\PhiNE Beam-Test Facility (BTF) is designed to search for the gauge boson of a new U(1)\rm U(1) interaction in the process e+^+e−→γ^-\rightarrow\gamma+A′\rm A', using the intense positron beam hitting a light target. The A′\rm A', usually referred as dark photon, is assumed to decay into invisible particles of a secluded sector and it can be observed by searching for an anomalous peak in the spectrum of the missing mass measured in events with a single photon in the final state. The measurement requires the determination of the 4-momentum of the recoil photon, performed by a homogeneous, highly segmented BGO crystals calorimeter. A significant improvement of the missing mass resolution is possible using an active target capable to determine the average position of the positron bunch with a resolution of less than 1 mm. This report presents the performance of a real size (2x2cm2)\rm (2x2 cm^2) PADME active target made of a thin (50 μ\mum) diamond sensor, with graphitic strips produced via laser irradiation on both sides. The measurements are based on data collected in a beam test at the BTF in November 2015.Comment: 7 pages, 10 figure

    The Frascati LINAC beam test facility performances and upgrades

    Get PDF
    The Beam-Test Facility (BTF) of the DAΦNE accelerator complex, in the Frascati National Laboratory of the INFN is in operation since 2004 for the high-energy particle and accelerator community. The performance of the BTF is discussed and the plans for the future upgrade of the facility are introduced

    Analisi della risposta sismica di un edificio campione nel Comune di Ariano Irpino (AV)

    Get PDF
    Nella pratica ingegneristica vengono usate correlazioni derivate da regressioni statistiche tra numero dei piani degli edifici e frequenze di risonanza. Tuttavia la discrepanza tra comportamento reale e valori aspettati può essere talvolta significativa, e solo l’acquisizione di dati sperimentali consente di comprendere il reale comportamento dinamico di una struttura. La sperimentazione, in situazioni anche complesse, e la raccolta di nuovi dati possono essere molto importanti nel campo dell’ingegneria strutturale. In questo articolo vengono presentati i risultati del monitoraggio sismico effettuato su un edificio campione in muratura (il municipio di Ariano Irpino), tipologia costruttiva largamente diffusa tra gli edifici pubblici strategici (ad esempio scuole, caserme ed ospedali). Sono state utilizzate 7 stazioni sismologiche a sei canali equipaggiate con sismometri ed accelerometri. I dati sismici sono stati acquisiti in modalità continua, in punti strategici della struttura, su diversi livelli, dal gennaio 2006 a dicembre 2007. Sono stati selezionati una ventina di terremoti di magnitudo bassa o intermedia (1.5 ≤ M ≤ 4.8) avvenuti a distanze epicentrali variabili da 4 a 116 km. Le registrazioni sono state analizzate sia mediante la tecnica dei rapporti spettrali rispetto alla base dell’edificio sia calcolando i rapporti spettrali tra componente orizzontale e verticale di ogni sensore. L’analisi svolta ha consentito di evidenziare numerose frequenze di vibrazione dell’edificio. Mediante simulazioni numeriche su un modello tridimensionale rappresentativo della struttura in esame è stato possibile associare i picchi in frequenza ai modi propri in campo lineare. In particolare, sono stati ben identificati i primi 3 modi di vibrazione (due flessionali ed uno rotazionale)

    Low energy high angular resolution neutral atom detection by means of micro-shuttering techniques: the BepiColombo SERENA/ELENA sensor

    Full text link
    The neutral sensor ELENA (Emitted Low-Energy Neutral Atoms) for the ESA cornerstone BepiColombo mission to Mercury (in the SERENA instrument package) is a new kind of low energetic neutral atoms instrument, mostly devoted to sputtering emission from planetary surfaces, from E ~20 eV up to E~5 keV, within 1-D (2x76 deg). ELENA is a Time-of-Flight (TOF) system, based on oscillating shutter (operated at frequencies up to a 100 kHz) and mechanical gratings: the incoming neutral particles directly impinge upon the entrance with a definite timing (START) and arrive to a STOP detector after a flight path. After a brief dissertation on the achievable scientific objectives, this paper describes the instrument, with the new design techniques approached for the neutral particles identification and the nano-techniques used for designing and manufacturing the nano-structure shuttering core of the ELENA sensor. The expected count-rates, based on the Hermean environment features, are shortly presented and discussed. Such design technologies could be fruitfully exported to different applications for planetary exploration.Comment: 11 page
    • …
    corecore