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Marcelli, Augusto
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Marcelli, Augusto
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- PublicationRestrictedA 3D imaging textural characterization of pyroclastic products from the 1538 AD Monte Nuovo eruption (Campi Flegrei, Italy)(2019)
; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ;The explosive volcanic event of the 1538 AD Monte Nuovo eruption (Volcanic Explosivity Index, VEI = 2) in the Campi Flegrei high-risk caldera (Italy) has a strategic significance in the framework of volcanology and volcanic hazard of caldera-forming magmatic systems. In fact, it represents the last and unique historical eruption of the highly populated Phlegraean restless-caldera, and its precursory and eruptive phenomena are well-known because they were described in detail by contemporaneous eyewitnesses. In this study, a set of samples representative of the complete stratigraphic sequence of the Monte Nuovo eruption was characterized using phase-contrast synchrotron radiation computed microtomography and quantitatively investigated through the development of a new protocol for 3D textural analysis of highly-vesiculated volcanic rocks. Previous studies of products from this eruption are available in the literature, mostly based on 2D imaging techniques, and thus provide a useful data set for comparison. The 3D textural measurements allow us to investigate the subvolcanic processes (mechanisms and timing of magma degassing) that occurred during magma ascent in the conduit for each stage of the eruption and their relationship with the variations in the eruptive style described in the contemporaneous accounts of the eruption. This information is fundamental for the definition of a volcanic eruption scenario for such low-VEI events, often recurrent in the history of the caldera, and is useful both for hazard assessment and emergency planning.587 8 - PublicationOpen AccessLunar Gravitational-wave Antenna(2021-04-01)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ;; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Monitoring of vibrational eigenmodes of an elastic body excited by gravitational waves was one of the first concepts proposed for the detection of gravitational waves. At laboratory scale, these experiments became known as resonant bar detectors first developed by Joseph Weber in the 1960s. Due to the dimensions of these bars, the targeted signal frequencies were in the kHz range. Weber also pointed out that monitoring of vibrations of Earth or the Moon could reveal gravitational waves in the mHz band. His Lunar Surface Gravimeter experiment deployed on the Moon by the Apollo 17 crew had a technical failure, which greatly reduced the science scope of the experiment. In this article, we revisit the idea and propose a Lunar Gravitational-Wave Antenna (LGWA). We find that LGWA could become an important partner observatory for joint observations with the space-borne, laser- interferometric detector LISA and at the same time contribute an independent science case due to LGWA’s unique features. Technical challenges need to be overcome for the deployment of the experiment, and development of inertial vibration sensor technology lays out a future path for this exciting detector concept.366 55 - PublicationOpen AccessTerahertz continuous wave spectroscopy: a portable advanced method for atmospheric gas sensing(2022-05-23)
; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ;Motivated by the increasing demand to monitor the air-quality, our study proved the feasibility of a new compact and portable experimental approach based on Terahertz (THz) continuous wave high resolution spectroscopy, to detect the presence of the air's contaminants as greenhouse gases (GHG) and volatile organic compounds (VOCs). In this specific work, we first characterized, determining their molar absorption coefficient in the spectral region (0.06-1.2) THz, the pure optical response of the vapor of five VOCs: methanol, ethanol, isopropanol, 1-butanol and 2-butanol. In particular, 1-butanol and 2-butanol are characterized for the first time in literature at THz frequencies. Then we studied the optical response of their mixtures achieved with ambient air and ethanol. The results show that it is possible for a differentiation of single components by describing their spectral absorption in terms of the linear combination of pure compounds absorption. This proof of concept for this apparatus study and set-up paves the way to the use of THz Continuous wave high resolution spectroscopy for the environmental tracking of air pollutants.37 41 - PublicationOpen AccessMineralogy and textures of riebeckitic asbestos (crocidolite): The role of single versus agglomerated fibres in toxicological experiments(2017-10-15)
; ; ; ; ; ; ; ; ; ; ;; ; ; ; ;; ; ;Asbestos may cause adverse effects, but relationship between mineralogy and texture of fibres versus toxicity is still lacking. Toxicological studies can be interpreted and compared only if quantitative features of fibres are determined. Here, riebeckitic ("crocidolite") amphibole fibres were analysed by XRPD, FTIR, SEM-EDS and EMP-WDS; only crystals with stochiometryA□BNa2C(Fe2+2.5Mg0.5)CFe3+2TSi8O22W(OH)2are present in the starting material used for the experiments. Fibres deposited from solutions of 0.1, 1, 10, 25, 50, 75 and 100mg/L were counted by image analysis using SEM images. At 0.1 and 1mg/L the fibres are well separated, whereas between 1 and 10mg/L they start to agglomerate. In-vitro tests performed on fibres deposited at the same mg/L concentrations show that the toxic potential follows a curvilinear increasing trend with a decreasing rate. Since the range of sizes of single fibres and their mineralogy are constant, this decreasing rate can be only attributed to the increasing amount of agglomerated fibres. Hence, single versus agglomerated fibre population is a factor that cannot be neglected in defining the final adverse effects of asbestos. The analytical protocol proposed here is valuable for any aero-dispersed dust, in polluted environments, as well as in the interpretation of experimental studies.87 36 - PublicationRestrictedApplication of micro-FTIR imaging in the Earth sciences(2010)
; ; ; ; ; ; ; ;Della Ventura, G.; Dipartimento Scienze Geologiche, Università Roma Tre, Roma, Italy ;Bellatreccia, F.; Dipartimento Scienze Geologiche, Università Roma Tre, Roma, Italy ;Marcelli, A.; INFN-Laboratori Nazionali di Frascati, Roma, Italy ;Cestelli Guidi, M.; INFN-Laboratori Nazionali di Frascati, Roma, Italy ;Piccinnini, M.; Porto Conte Ricerche S.r.l, Sassari, Italy ;Cavallo, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Piochi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; ; ; ; ; In this paper we describe recent applications of micro-infrared imaging in the Earth sciences. We address, in particular, the use of Fourier-transform infrared (FTIR) spectroscopy in characterizing the zoning and speciation of H and C in a variety of geological materials, including microporous minerals, nominally anhydrous volcanic minerals (NAMs), and crystal inclusions. These investigations show that use of the modern techniques of FTIR imaging enables detection of the zoning of volatile species across the studied samples, and possible configuration changes of structurally-bound carbon molecular species (e.g., CO2 vs CO3) during crystal growth. Such features, which are not accessible with other micro-analytical techniques, may provide information about the physicochemical properties which act as constraints in the genesis of the samples, and important information about the evolution of the geological system. Tests performed with focal-plane-array detectors (FPA) show that resolution close to the diffraction limit can be achieved if the amounts of the target molecules in the sample are substantially different. We also point out the possibility of using FTIR imaging for investigations under non-ambient conditions.291 23 - PublicationRestrictedReal-time quantitative detection of styrene in atmosphere in presence of other volatile-organic compounds using a portable deviceExposure to styrene is a major safety concern in the fibreglass processing industry. This compound is classified by the International Agency for Research on Cancer as a possible human carcinogen. Several types of analytical equipment exist for detecting volatile organic compounds (VOCs) in the atmosphere; however, most of them operate ex-situ or do not provide easy discrimination between different molecules. This work introduces an improved and portable method based on FTIR spectroscopy to analyse toxic gaseous substances in working sites down to a concentration of less than 4 ppm. Styrene and a combination of VOCs typically associated with it in industrial processes, such as acetone, ethanol, xylene and isopropanol, have been used to calibrate and test the methodology. The results demonstrate that the technique offers the possibility to discriminate between different gaseous compounds in the atmosphere with a high degree of confidence and obtain very accurate quantitative information on their concentration, down to the ppm level, even when different VOCs are present in a mixture.
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