1,673 research outputs found

    A WebGis tool for seismic hazard scenarios and risk analysis

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    The WebGis development represents a natural answer to the growing requests for dissemination and use of geographical information data. WebGis originates from a combination of web technology and the Geographical Information System, which is a recognised technology that is mainly composed of data handling tools for storage, recovery, management and analysis of spatial data. Here, we illustrate two examples of seismic hazard and risk analysis through the WebGis system in terms of architecture and content. The first presents ground shaking scenarios associated with the repetition of the earthquake that struck the Lake of Garda area (northern Italy) in 2004. The second shows data and results of a more extensive analysis of seismic risk in the western part of the Liguria region (north-western Italy) for residential buildings, strategic structures and historic architecture. The adoption of a freeware application (ALOVMap) assures easy exportability of the WebGis structures for projects dealing with natural hazard evaluation

    Damage distribution and seismological model of the November 24, 2004, Salo' (Northern Italy) earthquake

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    The West side of lake of Garda, in Northern Italy, was struck by a ML=5.2 earthquake on November 24, 2004. The felt area is rather large (from Venice to Milan) and the damaged area consists of 66 municipalities, with a number of homeless of about 2200 and estimated direct damages of 215 millions of euros. Most of the damaged structures are old masonry buildings and churches, while there were almost no damage to reinforced concrete structures. The observed distribution of macroseismic intensity shows a strong azimuthal dependence, with high intensity level in a 10x10 km2 area located SW to the epicentre and rather large dispersion of values (ranging from V to VII-VIII) in the first 10 km epicentral distance. Taking into account the vulnerability level of the damaged structures and the features of the geological formations, we tried to explain the observed damage distribution in terms of finite fault properties of the source, despite the moderate magnitude of the event. Thus we hypothesised a fault geometry from seismotectonic considerations and we simulated the event by a high frequency simulation technique (Deterministic Stochastic Method, DSM). The synthetic ground motion parameters were converted into intensity values by empirical relationships and local geological conditions were considered to explain some discrepancies between simulated and observed intensities. It was possible to adequately reproduce both the observed distribution of macroseismic intensity and the ground motion recorded by an accelerometric station located at about 13 km epicentral distance

    Front-end Electronics and Optimal Ganging Schemes for Single Photon Detection with Large Arrays of SiPMs in Liquid Argon

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    The operation of large arrays of silicon photomultipliers (SiPM) in tanks of noble liquids requires low noise, low power front-end amplifiers, able to operate reliably in the cryogenic environment. A suitable amplifier needs to be paired with a proper SiPM ganging scheme, meaning the series/parallel combination of SiPMs at its input. This paper presents a simple model to estimate the ganging scheme that gives the best signal to noise ratio once the basic electrical characteristics of the SiPM and amplifier are known. To prove the validity of the model, we used an amplifier based on discrete components, which achieves a white voltage noise in the 0.25-0.37 nV/√\surdHz range at liquid nitrogen temperature, while drawing 2-5 mW of power. Combined with the optimal ganging scheme obtained with the model, the amplifier demonstrated excellent single photon sensitivity up to 96 6x6 mm2^2 SiPMs (total area 34.6 cm2^2, S/N ≃\simeq 8-11). The measured results are in a good match with calculated values, predicting the possibility to achieve a clear separation of photoelectron peaks also with larger areas

    TeO2_2 bolometers with Cherenkov signal tagging: towards next-generation neutrinoless double beta decay experiments

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    CUORE, an array of 988 TeO2_2 bolometers, is about to be one of the most sensitive experiments searching for neutrinoless double-beta decay. Its sensitivity could be further improved by removing the background from α\alpha radioactivity. A few years ago it has been pointed out that the signal from β\betas can be tagged by detecting the emitted Cherenkov light, which is not produced by α\alphas. In this paper we confirm this possibility. For the first time we measured the Cherenkov light emitted by a CUORE crystal, and found it to be 100 eV at the QQ-value of the decay. To completely reject the α\alpha background, we compute that one needs light detectors with baseline noise below 20 eV RMS, a value which is 3-4 times smaller than the average noise of the bolometric light detectors we are using. We point out that an improved light detector technology must be developed to obtain TeO2_2 bolometric experiments able to probe the inverted hierarchy of neutrino masses.Comment: 5 pages, 4 figures. Added referee correction

    Polydatin beneficial effects in zebrafish larvae undergoing multiple stress types

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    none8noPolydatin is a polyphenol, whose beneficial properties, including anti-inflammatory and antioxidant activity, have been largely demonstrated. At the same time, copper has an important role in the correct organism homeostasis and alteration of its concentration can induce oxidative stress. In this study, the efficacy of polydatin to counteract the stress induced by CuSO4 exposure or by caudal fin amputation was investigated in zebrafish larvae. The study revealed that polydatin can reduced the stress induced by a 2 h exposure to 10 µM CuSO4 by lowering the levels of il1b and cxcl8b.1 and reducing neutrophils migration in the head and along the lateral line. Similarly, polydatin administration reduced the number of neutrophils in the area of fin cut. In addition, polydatin upregulates the expression of sod1 mRNA and CAT activity, both involved in the antioxidant response. Most of the results obtained in this study support the working hypothesis that polydatin administration can modulate stress response and its action is more effective in mitigating the effects rather than in preventing chemical damages.openPessina A.; Di Vincenzo M.; Maradonna F.; Marchegiani F.; Olivieri F.; Randazzo B.; Gioacchini G.; Carnevali O.Pessina, A.; Di Vincenzo, M.; Maradonna, F.; Marchegiani, F.; Olivieri, F.; Randazzo, B.; Gioacchini, G.; Carnevali, O

    An integrated 0D/1D/3D numerical framework to predict performance, emissions, knock and heat transfer in ICEs fueled with NH3–H2 mixtures: The conversion of a marine Diesel engine as case study

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    In the maritime transportation, e-fuels represent a valid alternative to fossil energy sour- ces, in order to accomplish the European Union goals in terms of climate neutrality. Among the e-fuels, the ammonia-hydrogen mixtures can play a leading role, as the combination of the two allows to exploit the advantages of each one, simultaneously compensating their gaps. The main goal of the present publication is the proposal of a robust numerical frame- work based on 0D, 1D and 3D tools for CFD analyses of internal combustion engines fueled with ammonia-hydrogen mixtures. The 1D engine model provides boundary conditions for the multi-dimensional in- vestigations and estimates the overall engine performance. 3D in-cylinder detailed ana- lyses are proficiently used to predict combustion efficiency (via the well-established G-equation model supported by laminar flame speed correlations for both ammonia and hydrogen) and emissions (with a detailed chemistry based approach). Heat transfer and knock tendency are evaluated as well, by in-house developed models. As for the 0D/1D chemical kinetics calculations, firstly they support 3D analyses (for example via the gen- eration of ignition delay time tables). Moreover, they allow insights on aspects such as NOx formation, to individuate mixture qualities able to strongly reduce the emissions
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