89 research outputs found

    Specifiche tecniche del progetto di potenziamento a mare del sistema di sorveglianza dell’area vulcanica dei Campi Flegrei

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    L’Istituto Nazionale di Geofisica e Vulcanologia per lo svolgimento delle attività istituzionali condotte dalla Sezione di Napoli - Osservatorio Vesuviano, ha necessità di estendere in mare il sistema di sorveglian- za dell’area vulcanica dei Campi Flegrei, sita in provincia di Napoli. Il sistema esistente, infatti, è costituito da varie reti di rilevamento di parametri geofisici e geochimici, tutte centralizzate presso la sede dell’Osservatorio, con punti stazione ubicati sulla terraferma. Solo una stazione sperimentale, denominata CUMAS (Cabled Underwater Multidisciplinary Acquisition System), è operativa nel Golfo di Pozzuoli a cir- ca 2.4 km a sud del Rione Terra. (Per una descrizione dei sistemi di monitoraggio gestiti dall’Osservatorio Vesuviano si rimanda al sito www.ov.ingv.it). Il progetto di potenziamento “EMSO-MedIT: Potenziamento delle infrastrutture multidisciplinari di ricerca marina in Sicilia, Campania e Puglia quale contributo alla ESFRI EMSO”, finanziato dal MIUR, ha fornito le risorse per realizzare un sistema di monitoraggio permanente anche nella parte sommersa dei Cam- pi Flegrei. Il presente rapporto tecnico descrive questo sistema di monitoraggio marino costiero per dati geofisici da fondo mare, da installare nel Golfo di Pozzuoli, che prevede l’acquisizione in continuo e la relativa tra- smissione dei dati in tempo reale verso la sala di sorveglianza sismica-vulcanica dell’Osservatorio. Esso sarà costituito da tre sistemi di acquisizione dati indipendenti ognuno composto da una boa (tipo meda elastica e/o a palo) connessa via cavo elettromeccanico (per l’energizzazione e la comunicazione) ad un modulo mul- ti-parametrico posizionato sul fondo del mare, ad una distanza massima di venti metri dal corpo morto (costi- tuente la zavorra a cui è ancorata la boa), ed equipaggiati con strumentazione elettronica di controllo e di ri- levamento di parametri geofisici

    Inferences on the source mechanisms of the 1930 Irpinia (Southern Italy) earthquake from simulations of the kinematic rupture process

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    We examine here a number of parameters that define the source of the earthquake that occurred on 23rd July 1930 in Southern Italy (in the Irpinia region). Starting from the source models proposed in different studies, we have simulated the acceleration field for each hypothesized model, and compared it with the macroseismic data. We then used the hybrid stochastic-deterministic technique proposed by Zollo et al. (1997) for the simulation of the ground motion associated with the rupture of an extended fault. The accelerations simulated for several sites were associated with the intensities using the empirical relationship proposed by Trifunac and Brady (1975), before being compared with the available data from the macroseismic catalogue. A good reproduction of the macroseismic field is provided by a normal fault striking in Apenninic direction (approximately NW-SE) and dipping 55° toward the SW

    Underwater acoustic channel properties in the Gulf of Naples and their effects on digital data transmission

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    ?In this paper we studied the physical properties of the Gulf of Naples (Southern Italy) for its use as a commu- nication channel for the acoustic transmission of digital data acquired by seismic instruments on the seafloor to a moored buoy. The acoustic link will be assured by high frequency acoustic modems operating with a central frequency of 100 kHz and a band pass of 10 kHz. The main operational requirements of data transmission con- cern the near horizontal acoustic link, the maximum depth of the sea being about 300 m and the planned hori- zontal distance between seismic instruments and buoy 2 km. This study constructs the signal-to-noise ratio maps to understand the limits beyond which the clarity of the transmission is no longer considered reliable. Using ray- theory, we compute the amplitudes of a transmitted signal at a grid of 21×12 receivers to calculate the transmis- sion loss at each receiver. The signal-to-noise ratio is finally computed for each receiver knowing also the trans- mitter source level and the acoustic noise level in the Gulf of Naples. The results show that the multipath effects predominate over the effects produced by the sound velocity gradient in the sea in the summer period. In the case of omnidirectional transmitters with a Source Level (SL) of 165 dB and a baud rate of 2.4 kbit/s, the results al- so show that distances of 1400-1600 m can be reached throughout the year for transmitter-receiver connections below 50 m depth in the underwater acoustic channel

    Underwater acoustic channel properties in the Gulf of Naples and their effects on digital data transmission

    Get PDF
    ?In this paper we studied the physical properties of the Gulf of Naples (Southern Italy) for its use as a commu- nication channel for the acoustic transmission of digital data acquired by seismic instruments on the seafloor to a moored buoy. The acoustic link will be assured by high frequency acoustic modems operating with a central frequency of 100 kHz and a band pass of 10 kHz. The main operational requirements of data transmission con- cern the near horizontal acoustic link, the maximum depth of the sea being about 300 m and the planned hori- zontal distance between seismic instruments and buoy 2 km. This study constructs the signal-to-noise ratio maps to understand the limits beyond which the clarity of the transmission is no longer considered reliable. Using ray- theory, we compute the amplitudes of a transmitted signal at a grid of 21×12 receivers to calculate the transmis- sion loss at each receiver. The signal-to-noise ratio is finally computed for each receiver knowing also the trans- mitter source level and the acoustic noise level in the Gulf of Naples. The results show that the multipath effects predominate over the effects produced by the sound velocity gradient in the sea in the summer period. In the case of omnidirectional transmitters with a Source Level (SL) of 165 dB and a baud rate of 2.4 kbit/s, the results al- so show that distances of 1400-1600 m can be reached throughout the year for transmitter-receiver connections below 50 m depth in the underwater acoustic channel

    Composition and biodiversity of soil and root-associated microbiome in Vitis vinifera cultivar Lambrusco distinguish the microbial terroir of the Lambrusco DOC protected designation of origin area on a local scale

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    Introduction Wines produced from the same grape cultivars but in different locations possess distinctive qualities leading to different consumer's appreciation, preferences, and thus purchase choices. Here, we explore the possible importance of microbiomes at the soil-plant interface as a determinant of the terroir properties in grapevine production, which confer specific growth performances and wine chemo-sensory properties at the local scale. MethodsIn particular, we investigated the variation in microbial communities associated with the roots of Vitis vinifera cultivar Lambrusco, as well as with surrounding bulk soils, in different vineyards across the "Consorzio Tutela Lambrusco DOC" protected designation of origin area (PDO, Emilia Romagna, Italy), considering viticultural sites located both inside and outside the consortium in two different seasons (June and November 2021). ResultsAccording to our findings, rhizospheric and soil microbiomes show significant structural differences in relation to the sampling site, regardless of seasonality, while endophytic microbiomes seem to be completely unaffected by such variables. Furthermore, a deeper insight into the microbial terroir of PDO areas highlighted the presence of some rhizospheric microorganisms enriched inside the consortium and characterizing the PDO regardless of both sampling season and farming strategy. These include Bacillus, Paenibacillus, and Azospirillum, which are all well-known plant growth-promoting bacteria. DiscussionTaken together, our results suggest a connection between soil and root microbiomes of V. vinifera cultivar Lambrusco and the local designation of origin, emphasizing the potential role of PDO-enriched plant growth-promoting bacteria in vine growing and final quality of the Lambrusco DOC wine

    Inkjet-printed graphene Hall mobility measurements and low-frequency noise characterization

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    We report room-temperature Hall mobility measurements, low-temperature magnetoresistance analysis, and low-frequency noise characterization of inkjet-printed graphene films on fused quartz and SiO2/Si substrates. We found that thermal annealing in vacuum at 450 ◦C is a necessary step in order to stabilize the Hall voltage across the devices, allowing their electrical characterization. The printed films present a minimum sheet resistance of 23.3 Ω/sq after annealing, and are n-type doped, with carrier concentrations in the low 1020 cm−3 range. The charge carrier mobility is found to increase with increasing film thickness, reaching a maximum value of 33 cm2 V−1 s−1 for a 480 nm-thick film printed on SiO2/Si. Low-frequency noise characterization shows a 1/f noise behavior and a Hooge parameter in the range of 0.1 – 1. These results represent the first in-depth electrical and noise characterization of transport in inkjet-printed graphene films, able to provide physical insights on the mechanisms at play

    Four Years of Continuous Seafloor Displacement Measurements in the Campi Flegrei Caldera

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    We present 4 years of continuous seafloor deformation measurements carried out in the Campi Flegrei caldera (Southern Italy), one of the most hazardous and populated volcanic areas in the world. The seafloor sector of the caldera has been monitored since early 2016 by the MEDUSA marine research infrastructure, consisting of four instrumented buoys installed where sea depth is less than 100 m. Each MEDUSA buoy is equipped with a cabled, seafloor module with geophysical and oceanographic sensors and a subaerial GPS station providing seafloor deformation and other environmental measures. Since April 2016, the GPS vertical displacements at the four buoys show a continuous uplift of the seafloor with cumulative measured uplift ranging between 8 and 20 cm. Despite the data being affected by environmental noise associated with sea and meteorological conditions, the horizontal GPS displacements on the buoys show a trend coherent with a radial deformation pattern. We use jointly the GPS horizontal and vertical velocities of seafloor and on-land deformations for modeling the volcanic source, finding that a spherical source fits best the GPS data. The geodetic data produced by MEDUSA has now been integrated with the data flow of other monitoring networks deployed on land at Campi Flegrei

    The role of sol–gel chemistry in the low-temperature formation of ZnO buffer layers for polymer solar cells with improved performance

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    A new approach is proposed in this work to chemically control the low-temperature sol-gel formation of ZnO thin films used as efficient electron transporting layers (ETLs) in inverted polymer solar cells (PSCs). The chemical composition of the ZnO sol-gel precursor was modified by systematically employing different [H2O]/[Zn2+] molar ratios in the starting sol formulation and evaluating their influence on film properties and PSC device performance. A thorough characterization of the obtained ZnO ETLs evidenced the key importance of the [H2O]/[Zn2+] molar ratio to achieve effective control on the sol-gel hydrolysis and condensation processes. Based on these evidences, a mechanism for the formation of the ZnO films at the low processing temperatures used in this work was proposed. PSC devices were fabricated incorporating ZnO ETLs obtained from ZnO sol precursor formulations with increasing [H2O]/[Zn2+] ratios and their photovoltaic characterization revealed the presence of a maximum device efficiency for intermediate [H2O]/[Zn2+] values. Finally, the effect of water in the ZnO sol precursor on the long-term (>1000 h) shelf-life of PSCs fabricated onto flexible PET substrates was investigated and a correlation was found between chemical composition of the ZnO sol precursor and device shelf-life. The results of this study give a clear demonstration of a viable strategy to achieve improved PSC device performance by chemically controlling the formation of the sol-gel based ZnO ETL at processing temperatures compatible with flexible plastic substrates and provide useful guidelines for the development of efficient sol-gel derived metal-oxide buffer layers for highly performing flexible photovoltaics
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