99 research outputs found

    Aerosol Optical Depth of the Main Aerosol Species over Italian Cities Based on the NASA/MERRA-2 Model Reanalysis

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    The Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2) provides data at 0.5° × 0.625° resolution covering a period from 1 January 1980 to the present. Natural and anthropogenic aerosols are simulated in MERRA-2, considering the Goddard chemistry, aerosol, radiation, and transport model. This model simulates the sources, sinks, and chemistry of mixed aerosol tracers: dust, sea salt, hydrophobic and hydrophilic black carbon and organic carbon, and sulfate. MERRA-2 aerosol reanalysis is a pioneering tool for investigating air quality issues, noteworthy for its global coverage and its distinction of aerosol speciation expressed in the form of aerosol optical depth (AOD). The aim of this work was to use the MERRA-2 reanalysis to study urban air pollution at a national scale by analyzing the AOD. AOD trends were evaluated for a 30-year period (1987–2017) over five Italian cities (Milan, Rome, Cagliari, Taranto, and Palermo) in order to investigate the impacts of urbanization, industrialization, air quality regulations, and regional transport on urban aerosol load. AOD evolution predicted by the MERRA-2 model in the period 2002–2017 showed a generalized decreasing trend over the selected cities. The anthropogenic signature on total AOD was between 50% and 80%, with the largest contribution deriving from sulfate

    Two years monitoring of soil N2O emissions on durum wheat in a Mediterranean area: the effect of tillage intensity and N-fertilizer rate

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    Two years monitoring of soil N2O emissions on durum wheat in a Mediterranean area: the effect of tillage intensity and N-fertilizer rate. EGU General Assembly 2016 Conference Abstracts, European Geophysical Unio

    Experimental Analysis of the Reaction Rate of Hydrated Class G Cement Powder at 11 bar PCO2 and Ambient Temperature

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    The aim of this work is to study the alteration of class G Cement at ambient temperature under a relatively high CO2 partial pressure through suitably designed laboratory experiments, in which cement hydration and carbonation are taken into account separately. First, the hydration process was carried out for 28 days to identify and quantify the hydrated solid phases formed. After the completion of hydration, accompanied by partial carbonation under atmospheric conditions, the carbonation process was investigated using a stirred micro-reactor by reacting cement powder with pure CO2(g) (PCO2 = 11 bar) and MilliQ water for different reaction times. The reaction time was varied to constrain the reaction kinetics of the carbonation process and to investigate the evolution of primary and secondary solid phases. Mineralogical analyses (X-ray Powder Diffraction and Scanning Electron Microscope) were carried out to this purpose. Water analyses were also performed by ion chromatography at the end of each experimental run to investigate the chemical effects of cement carbonation on the aqueous solution. The carbonation degree was calculated from the results of Thermo-Gravimetric analysis (TGA). The main results of these experiments is the quick conversion of portlandite and Ca1.60SiO3.6·2.58H2O (C-S-H) to calcite. In fact, the carbonation degree attains 80% after 6 hours of reaction time. Experimental outcomes will be simulated by means of the PHREEQC software package to obtain further indications on cement carbonatio

    WRF Sensitivity Analysis in Wind and Temperature Fields Simulation for the Northern Sahara and the Mediterranean Basin

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    Different configurations for the Weather Research and Forecasting (WRF) model were evaluated to improve wind and temperature fields predictions in the Northern Sahara and the Mediterranean basin. Eight setups, associated with different combinations of the surface layer physical parameters, the land surface model, and the grid nudging parameters, were considered. Numerical simulations covered the entire month of November 2017. Model results were compared with surface data from meteorological stations. The introduction of the grid nudging parameters leads to a general improvement of the modeled 10 m wind speed and 2 m temperature. In particular, nudging of wind speed parameter inside the planetary boundary layer (PBL) provides the most remarkable differences. In contrast, the nudging of temperature and relative humidity parameters inside the PBL may be switched off to reduce computational time and data storage. Furthermore, it was shown that the prediction of the 10 m wind speed and 2 m temperature is quite sensitive to the choice of the surface layer scheme and the land surface model. This paper provides useful suggestions to improve the setup of the WRF model in the Northern Sahara and the Mediterranean basin. These results are also relevant for topics related with the emission of mineral dust and sea spray within the Mediterranean region

    LIFE+IPNOA mobile prototype for the monitoring of soil N2O emissions from arable crops: First-year results on durum wheat

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    Agricultural activities are co-responsible for the emission of the most important greenhouse gases: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Development of methodologies to improve monitoring techniques for N2O are still needful. The LIFE+IPNOA project aims to improve the emissions monitoring of nitrous oxide from agricultural soils and to identify the agricultural practices that can limit N2O production. In order to achieve this objective, both a mobile and a stationary instrument were developed and validated. Several experimental field trials were set up in two different sites investigating the most representative crops of Tuscany (CentralItaly), namely durum wheat, maize, sunflower, tomato and faba bean. The field trials were realized in order to test the effect on N2O emissions of key factors: tillage intensity, nitrogen fertiliser rate and irrigation. The field trial on durum wheat was set up in 2013 to test the effect of tillage intensity (minimum and conventional tillage) and nitrogen fertilisation rate (0, 110, 170 kg N ha–1) on soil N2O flux. Monitoring was carried out using the IPNOA mobile prototype. Preliminary results on N2O emissions for the durum wheat growing season showed that mean daily N2O fluxes ranged from –0.13 to 6.43 mg m–2 day–1 and cumulative N2O-N emissions over the period ranged from 827 to 2340 g N2O-N ha–1. Tillage did not affect N2O flux while increasing nitrogen fertilisation rate resulted to significantly increase N2O emissions. The IPNOA mobile prototype performed well during this first year of monitoring, allowing to catch both very low fluxes and peaks on N2O emissions after nitrogen supply, showing a good suitability to the field conditions

    LIFE15 ENV/IT/000392 − LIFE VITISOM Project, viticulture innovation technology and GHG emission monitoring

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    The main aim of the LIFE VITISOM Project is to promote an innovative solution for the management of the organic fertilisation in the viticultural sector. In parallel, different activities of monitoring of impacts have been planned. Specifically, a deep study about GHG emissions has been organised. In this context, different studies are being carried out: a continuous monitoring of net carbon fluxes (NEE) through the Eddy Covariance method, followed by University of Padua which allows data to be obtained at vineyard ecosystem level; a spatial monitoring of CH4, N2O and CO2, through a mobile instrument for measuring the variation of GHG developed by West Systems within the LIFE+ IPNOA Project. In the first case, two Eddy Covariance towers have been installed, one at Guido Berlucchi (Franciacorta, Lombardy) and one at Bosco del Merlo (Lison, Veneto). Additionally, spatial monitoring is being carried out in five testing sites involved in the LIFE VITISOM project. In this case, different organic fertilisation managements are compared

    Dichiarazione ICRP sulle reazioni tissutali ed effetti immediati e tardivi delle radiazioni nei tessuti e negli organi normali - Dosi soglia per le reazioni tissutali nell’ambito della radioprotezione

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    La pubblicazione ICRP 118 riesamina gli effetti precoci e tardivi delle radiazioni ionizzanti nei diversi organi ed apparati e fornisce stime aggiornate sulle dosi soglia per l'induzione delle numerose reazioni tissutali analizzate. In particolare, a seguito dei progressi nelle conoscenze radiobiologiche e cliniche, pubblicati in numerosi testi specialistici, vengono dettagliatamente presentate le evidenze che hanno condotto alle modificazioni, rispetto alle Raccomandazioni ICRP 103/2007, nella individuazione delle dosi soglia per la induzione della cataratta e delle patologie del sistema circolatorio da parte delle radiazioni ionizzanti. A queste rilevanti considerazioni si affiancano gli approfonditi aggiornamenti sulle conoscenze radiobiologiche e cliniche e le integrazioni delle dosi soglia, individuate in modo più articolato rispetto alle precedenti pubblicazioni, per tutte le altre reazioni tissutali, che rendono questo documento un indispensabile strumento di lavoro e di analisi per tutti coloro che si occupano di radioprotezione, con particolare riferimento agli specialisti di radioprotezione medica. La traduzione in italiano dell’intero testo vuole facilitare la diffusione delle peculiari informazioni contenute nella pubblicazione e motivare una sempre più approfondita ricerca in questo settore che indubbiamente contribuisce a ridurre i rischi derivanti dall’esposizione alle radiazioni ionizzanti. La realizzazione della versione italiana di questa pubblicazione ha richiesto un notevole impegno qualitativo e quantitativo ed è stata possibile per il considerevole e qualificante contributo dei medici dell’AIRM e dei membri del Comitato Internazionale dell'AIRP. A tutti coloro che hanno collaborato alla sua traduzione, revisione e pubblicazione con notevole spirito di sacrificio, è rivolto l'apprezzamento e la riconoscenza delle nostre Associazioni, che riuniscono gli operatori attivi nei vari settori di interesse della radioprotezione

    Phenomenology of Strangeness enhancement in heavy ion collisions

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    We give an overview of the phenomenology of strangeness enhancement in heavy ion collisions, within the paradigm of the statistical model of particle production. We argue that, while strangeness enhancement data is suggestive of a phase transition, the mechanism triggering enhancement is still elusive. We study the feasibility to constrain this mechanism by determining the scaling variable of strangeness enhancement. We further argue that to test the applicability of the statistical model generally, and to confirm our interpretation of the statistical physics responsible for strangeness enhancement, the scaling of strange particle fluctuations (K/Ï€K/\pi and other particles) w.r.t. yields has to be explored.Comment: Plenary talk, SQM2008, Beijing, China Minor stylistic revisions, discussion on scaling of enhancement added, references update
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