EDURISK e sapere tecnico | 2002 -2011

Summary of the seismic risk education activities carried out within the projects edurisk 2002 to 2011, addressed to students of vocational schools, their families and to an adult audience. The information, mostly of a technical nature, introduces concepts of vulnerability and esposition as factors on which act to reduce the level of ris

A WebGis tool for seismic hazard scenarios and risk analysis

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

Monolithic current-sensitive preamplifier for the Accordion LAr calorimeter

Abstract Monolithic current-sensitive preamplifiers matching large detector capacitances, suitable for the Accordion LAr calorimeter prototype, have been designed and fabricated in an ion-implanted GaAs MESFET process. After pulse shaping with an CR-RC 2 filter, the equivalent noise charge is at least a factor of 2 lower than the value reached so far with existing hybrids circuits, without increasing the power dissipation. This preamplifier has a fast response and large dynamic range. Results show that it is still possible to further reduce the noise and extend the dynamic range; this is likely to be obtained in a new version presently being developed

Cos’è successo a Siena il 26 maggio 1798 ? Un’iniziativa interdisciplinare per la valutazione del possibile impatto di un futuro «massimo sismico» su una città-monumento

L’importanza di un terremoto non dipende solo dalla sua intensità epicentrale. Quello del 26 maggio 1798 (Io VII MCS secondo CPTI04) non si può dire una catastrofe ma è di certo un evento «strategico». Si tratta, infatti, del massimo terremoto storico conosciuto per Siena, che è una delle maggiori attrazioni turistiche e quindi uno dei luoghi più frequentati di questo paese. Nell’ultimo ventennio il terremoto del 1798 è stato più volte studiato, sia da sismologi storici nell’ambito delle attività di revisione del catalogo PFG promosse dal GNDT e dall’ING/INGV (Castelli e Camassi, 1995; Castelli et al., 1996; Boschi et al., 1997; Boschi et al., 2000), sia da storici dell’architettura (Gennari, 2005). Siamo ancora lontani dall’aver completamente esplorato la copiosissima documentazione storica potenzialmente utile per una ricostruzione degli effetti di questo terremoto nel centro urbano senese. Tuttavia il campione reso disponibile dagli studi fatti finora è abbastanza significativo da rendere possibile l’avvio di un progetto di microzonazione del centro storico senese e di una serie di indagini miranti a comprendere cosa realmente successe a Siena il 26 maggio 1798 e, per conseguenza, quali effetti ci si possa attendere in occasione di un futuro terremoto di analoga portata. Il centro storico senese ha infatti conservato, almeno nelle grandi linee, una fisionomia molto simile a quella che aveva del 1798 e questa circostanza offre l’opportunità di attualizzare l’esperienza del terremoto del 1798 contribuendo alla identificazione delle eventuali criticità attese in caso di terremoti futuri. Si è perciò creato un gruppo di studio interdisciplinare (geofisica, architettura, sismologia storica, ingegneria sismica, geologia, ecc.) che ha cominciato a predisporre gli elementi necessari per questa ricostruzione. La base di dati storici di cui si dispone comprende descrizioni di danno più o meno dettagliate per circa seicento edifici senesi, su un migliaio da cui era composto il centro urbano nel 1798. Questo campione comprende sia edifici monumentali o comunque di vaste proporzioni (palazzi gentilizi e case di abitazione multipla, chiese, conventi, opifici) sia edifici non monumentali. Il nostro primo scopo è una ricostruzione dettagliata della distribuzione del danno del terremoto del 1798 nell’area urbana. Utilizzando cartografia storica pressoché coeva al terremoto (cfr. Gennari, 2005) e grazie all’impiego di un GIS, è stato possibile trasporre le informazioni storiche sottoforma di carte tematiche (Danno, Vulnerabilità, Interventi richiesti, eccetera). Le Figg. 1 e 2 presentano due esempi di tematismi derivati da dati archivistici. In parallelo a questa analisi verrà svolta una indagine a campione su una ventina di edifici rappresentativi per i quali si eseguiranno stime di comportamento dinamico con la tecnica del tremore sismico ambientale. A completamento della caratterizzazione della risposta sismica dei terreni nell’area del centro storico saranno svolte analisi geologiche e sismiche per definire le aree in cui l’assetto del sottosuolo rende ipotizzabili fenomeni di amplificazione del moto sismico del suolo. Tutti i risultati verranno raccolti in una base dati comune e implementati nel GIS (Figura 2) L’analisi congiunta dei dati di danno (opportunamente interpretati in termini di risposta sismica locale utilizzando il metodo proposto da Goretti e Dolce, 2004; Goretti, 2006) e delle analisi geofisiche e geologiche permetterà di individuare quelle parti del patrimonio edilizio storico più esposte a danno in caso di futuri eventi sismici

Cryogenic light detectors with enhanced performance for rare events physics

We have developed and tested a new way of coupling bolometric light detectors to scintillating crystal bolometers based upon simply resting the light detector on the crystal surface, held in position only by gravity. This straightforward mounting results in three important improvements: (1) it decreases the amount of non-active materials needed to assemble the detector, (2) it substantially increases the light collection efficiency by minimizing the light losses induced by the mounting structure, and (3) it enhances the thermal signal induced in the light detector thanks to the extremely weak thermal link to the thermal bath. We tested this new technique with a 16 cm$^2$ Ge light detector with thermistor readout sitting on the surface of a large TeO$_2$ bolometer. The light collection efficiency was increased by greater than 50\% compared to previously tested alternative mountings. We obtained a baseline energy resolution on the light detector of 20~eV RMS that, together with increased light collection, enabled us to obtain the best $\alpha$ vs $\beta/\gamma$ discrimination ever obtained with massive TeO$_2$ crystals. At the same time we achieved rise and decay times of 0.8 and 1.6 ms, respectively. This superb performance meets all of the requirements for the CUPID (CUORE Upgrade with Particle IDentification) experiment, which is a 1-ton scintillating bolometer follow up to CUORE.Comment: 6 pages, 4 figure

Development of gasoline-ethanol blends laminar flame speed correlations at full-load Si engine conditions via 1D simulations

Nowadays, most of the engineering development in the field of Spark-Ignited (SI) Internal Combustion Engines (ICEs) is supported by 3D-CFD simulations relying on flamelet combustion models. Such kind of models require laminar flame speed as an input to be specified by the user. While several laminar flame speed correlations are available in literature, for gasoline and pure ethanol at ambient conditions, there is a lack of correlations describing laminar flame speed of gasoline-ethanol blends, for different ethanol volume content, at conditions deemed to be representative of engine-like conditions. Toluene Reference Fuel surrogates with addition of ethanol (ETRF), suitable for representing gasoline-ethanol blends up to 85% vol. ethanol content are formulated. Thanks to these surrogates, 1D premixed laminar flame speed calculations are performed at selected engine-relevant conditions for a E5, E20 and E85 fuels. As a final outcome, three different laminar flame speed correlations based on the chemistry-based calculations are derived for E5, E20 and E85 gasoline-ethanol fuel blends focusing on typical full-load engine conditions. Such kind of correlations can be easily implemented in any 3D-CFD code to provide a chemistry-grounded estimation of laminar flame speed during combustion calculations. Such correlations are of practical use, since they might help in developing the next generation of bio-fuels powered internal combustion engines

Seismic risk assessment of italian seaports: the case of Ancona (Italy)

A National research project was recently carried out to develop a robust methodology for the design and retrofit of wharves structures located in areas of high to moderate seismicity. A detailed census of the Italian major seaports was performed using purposely devised questionnaires and Ancona harbor was chosen for a detailed investigation with the aim of providing risk assessment guidelines. This port has been selected as representative of a moderate seismicity area (expected peak ground acceleration of 0.25 g with a return period of 475 yrs). Ancona is the first harbor in the Adriatic sea, with more than a 1.500.000 passenger service and 150.000 trucks transit. It is equipped with 30 wharfs, 25 of which built in 1965-1975. To compute deterministic ground shaking scenarios, predictive empirical models have been used. At the same time advanced numerical simulation have been carried out both at high (0.7-30 Hz) and low (0-1.3) frequency ranges. The contributions of site effects and liquefaction have been also taken into account in damage estimation. Standard risk assessment has been performed using the empirical curves implemented in HAZUS program (NIBS, 2004), supported by recent studies (Lessloss, 2006, Del. 89) on damage observed after the 2003 event in Lefkas (Greece)

Monolithic GaAs current-sensitive cryogenic preamplifier for calorimetry applications

We have realized low-noise monolithic GaAs preamplifiers using ion- implanted technology , to operate under low temperature and high radiation field conditions. The evaluation of noise, amplitude and timing distributions of a batch taken after first mass-production run is presented. The current-sensitive preamplifier is linear up to 8 mA of input current and able to cope a 2.2 nF detector capacitance, showing fast response ( GBW product ∼ 1.7GHz) and very low series noise. Very good noise performance at LAr temperature is obtained by using large area MESFET ( l · w = 3. 24000μm 2 ) as a head transistor, which exhibits at 8mA standing current and only 10mW power dissipation, intrinsic gain μ = g m · r ds = 15 and noise referred to the input 0.30 ÷ 0.35 H z n ¯ V According to our estimation, second stage noise contribution is negligible. Radiation damage from neutrons and γ-irradiations as well as protection network against HV discharges are discussed

The revision of the 30 October 1901 earthquake, west of Lake Garda (northern Italy)

On 24 November 2004 an earthquake (Mw 5.0) struck the west side of Lake Garda (northern Italy), producing moderate but widespread damage. It provided the opportunity of reviewing the seismicity of all the area over the past two centuries, whose former most significant event is the 30 October 1901 earthquake (Mw 5.5), while other minor but damaging events are the 5 January 1892 (Mw=5.0) and 16 November 1898 (Mw=4.6) earthquakes. On the reviewing we found common similarities in ground shaking distribution as recurrent damaged spots, amplification zones due to local site condition or energy radiation We believe that these findings are suitable to provide information for provisional purposes in low hazard level area hampered by the lack of knowledge about the seismic sources. New data are provided both in MCS scale and EMS. The sensitivity of a source parameters estimation technique was evaluated for the major event