40 results on '"Davide Lena"'
Search Results
2. Small-Signal Circuit Model for Synchronous Buck DC/DC Converter featuring ZVS at Low-Side.
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Francesco Gabriele, Fabio Pareschi, Gianluca Setti, Riccardo Rovatti, Davide Lena, and Maria Rosa Borghi
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- 2023
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3. Miniaturized Wearable Optical Silicon Sensor for PPG Measurements.
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Piero Giorgio Fallica, Davide Lena, Francesco Rundo, and Sabrina Conoci
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- 2021
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4. An accurate electro-thermal model of SiC power mosfets for fast simulations.
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Davide Lena, Irene Buraioli, Alberto Bocca, Danilo Demarchi, and Alberto Macii
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- 2018
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5. Training a classifier for activity recognition using body motion simulation.
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Michelangelo Grosso, Davide Lena, Salvatore Rinaudo, David Alejandro Fernandez Guzman, and Danilo Demarchi
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- 2017
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6. Live Demonstration of Portable Systems based on Silicon Sensors for the monitoring of Physiological Parameters of Driver Drowsiness and Pulse Wave Velocity.
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Sabrina Conoci, Francesco Rundo, Giorgio Fallica, Davide Lena, Irene Buraioli, and Danilo Demarchi
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- 2018
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7. A nuclear ionized gas outflow in the Seyfert 2 galaxy UGC 2024
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Dania Muñoz-Vergara, Neil M Nagar, Venkatessh Ramakrishnan, Carolina Finlez, Thaisa Storchi-Bergmann, Roy Slater, Veronica Firpo, Pedro K Humire, Pamela Soto-Pinto, Steven B Kraemer, Davide Lena, Andrew Robinson, Rogemar A Riffel, D Michael Crenshaw, Martin S Elvis, T C Fischer, Allan Schnorr-Müller, and Henrique R Schmitt
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- 2019
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8. Energy-efficient battery charging in electric vehicles with solar panels.
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Michelangelo Grosso, Davide Lena, Alberto Bocca, Alberto Macii, and Salvatore Rinaudo
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- 2016
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9. A compact IGBT electro-thermal model in Verilog-A for fast system-level simulation.
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Davide Lena, Michelangelo Grosso, Alberto Bocca, Alberto Macii, and Salvatore Rinaudo
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- 2016
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10. Miniaturized Wearable Optical Silicon Sensor for PPG Measurements
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Piero Fallica, Davide Lena, Francesco Rundo, and Sabrina Conoci
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- 2022
11. Continuity and Innovation in Pottery Technology: The Karst Region (North-East Italy) from Neolithic to Early Bronze Age
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Federico Bernardini, Manuela Montagnari Kokelj, Matteo Velicogna, Nicolò Barago, Davide Lenaz, Angelo De Min, and Elena Leghissa
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pottery ,Northeastern Italy ,Neolithic ,Copper Age ,Early Bronze Age ,X-ray diffraction ,Archaeology ,CC1-960 - Abstract
This paper explores the development of pottery technology in the Trieste Karst region (North-East Italy) from the Neolithic to the Early Bronze Age (EBA). It also seeks to identify cultural links with other areas by examining potentially imported vessels. Archaeometric analyses (X-ray diffraction and optical microscopy) reveal significant differences between Neolithic ceramics (Danilo–Vlaška Group) and the majority of Late Copper Age (LCA)/Early Bronze Age (EBA) pottery (primarily associated with the Ljubljana Culture and a few with the Cetina Culture). Neolithic pottery displays consistent characteristics across all vessel types, including coarse grain, prevalent sparry calcite temper, and the absence of grog. In contrast, most LCA and EBA vessels exhibit distinct features such as very fine-grained paste, no sparry calcite, notable use of grog temper, higher quartz, muscovite, and flint content. Notably, from a technological perspective, the analyzed Cetina vessels bear a strong resemblance to the majority of LCA ceramics. The differences between Neolithic and LCA/EBA vessels clearly suggest the use of new raw materials, recipes, and techniques, likely reflecting changes in cultural and social contexts and potential connections with the core area of the Ljubljana Culture.
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- 2024
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12. Accuracy of a new instrument for noninvasive evaluation of pulse wave velocity: the Arterial sTiffness faitHful tOol aSsessment project
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Danilo Demarchi, Francesco Tosello, Anna Astarita, Luca Sabia, Eleonora Avenatti, Franco Veglio, Marco Cesareo, Giulia Mingrone, Dario Leone, Alessandro Sanginario, Irene Buraioli, Alberto Milan, Lorenzo Airale, Davide Lena, and Fabrizio Vallelonga
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medicine.medical_specialty ,Physiology ,pulse wave velocity ,arterial stiffness ,carotid--femoral pulse wave velocity ,hypertension-mediated organ damage ,noninvasive evaluation ,risk factor ,Carotid Arteries ,Carotid-Femoral Pulse Wave Velocity ,Humans ,Reproducibility of Results ,Risk Factors ,Pulse Wave Analysis ,Vascular Stiffness ,Internal medicine ,Internal Medicine ,medicine ,New device ,Risk factor ,Pulse wave velocity ,Reproducibility ,business.industry ,Large artery ,medicine.disease ,Clinical Practice ,Cardiology ,Arterial stiffness ,Reference device ,Cardiology and Cardiovascular Medicine ,business - Abstract
BACKGROUND Large artery stiffness, assessed by carotid--femoral pulse wave velocity (cfPWV), is a major risk factor for cardiovascular events, commonly used for risk stratification. Currently, the reference device for noninvasive cfPWV is SphygmoCor but its cost and technically challenging use limit its diffusion in clinical practice. AIM To validate a new device for noninvasive assessment of cfPWV, ATHOS (Arterial sTiffness faitHful tOol aSsessment), designed in collaboration with the Politecnico di Torino, against the reference noninvasive method represented by SphygmoCor. METHODS Ninety healthy volunteers were recruited. In each volunteer, we assessed cfPWV, using SphygmoCor (PWVSphygmoCor) and ATHOS (PWVATHOS) devices in an alternate fashion, following the ARTERY Society guidelines. The accuracy was assessed by Bland--Altman plot, and reproducibility was assessed by interoperator correlation coefficient (ICC). RESULTS Mean PWVATHOS and mean PWVSphygmoCor were 7.88 ± 1.96 and 7.72 ± 1.95 m/s, respectively. Mean difference between devices was 0.15 ± 0.56 m/s, with a high correlation between measurements (r = 0.959, P
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- 2021
13. A New Noninvasive System for Clinical Pulse Wave Velocity Assessment: The Athos Device
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Alessandro Sanginario, Davide Lena, Alberto Milan, Dario Leone, Danilo Demarchi, Irene Buraioli, and Giulia Mingrone
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Correctness ,business.product_category ,Computer science ,Interface (computing) ,pulse wave velocity ,Biomedical Engineering ,02 engineering and technology ,Pulse Wave Analysis ,Arterial pulse ,arterial stiffness ,intersecting tangent algorithm ,pulse transit time ,tonometry ,Software ,0202 electrical engineering, electronic engineering, information engineering ,Humans ,Electrical and Electronic Engineering ,MATLAB ,Pulse wave velocity ,Simulation ,computer.programming_language ,Graphical user interface ,business.industry ,020208 electrical & electronic engineering ,Process (computing) ,Reproducibility of Results ,Femoral Artery ,Laptop ,business ,computer ,Algorithms - Abstract
This paper presents a low cost, noninvasive, clinical-grade Pulse Wave Velocity evaluation device. The proposed system relies on a simultaneous acquisition of femoral and carotid pulse waves to improve estimation accuracy and correctness. The sensors used are two high precision MEMS force sensors, encapsulated in two ergonomic probes, and connected to the main unit. Data are then wirelessly transmitted to a standard laptop, where a dedicated graphical user interface (GUI) runs for analysis and recording. Besides the interface, the Athos system provides a Matlab algorithm to process the signals quickly and achieve a reliable PWV assessment. To better compare the results at the end of each analysis, a detailed report is generated, including all the relevant examination information (subject data, mean PTT, and obtained PWV). A pre-clinical study was conducted to validate the system by realizing several Pulse Wave Velocity measurements on ten heterogeneous healthy subjects of different ages. The collected results were then compared with those measured by a well-established and largely more expensive clinical device (SphygmoCor).
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- 2021
14. The quest for dual and binary supermassive black holes: A multi-messenger view
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Rubén Herrero-Illana, Zoltan Haiman, Bernd Husemann, Pedro R. Capelo, Lisa Steinborn, Stefano Bianchi, Enrico Piconcelli, Margherita Giustini, Miguel A. Pérez-Torres, Alberto Sesana, Monica Colpi, S. Komossa, Kazushi Iwasawa, Sándor Frey, Davide Lena, Maria Charisi, Nora Loiseau, Zsolt Paragi, Elisabeta Lusso, Matteo Guainazzi, Cristian Vignali, Massimo Dotti, Jessie C. Runnoe, Tamara Bogdanovic, Krisztina É. Gabányi, Lucio Mayer, Noelia Herrera Ruiz, Marta Volonteri, Luciano del Valle, Alessandra De Rosa, Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFISICA DE ANDALUCIA (IAA), SEV-2017-0709, Unidad de Excelencia Científica María de Maeztu Instituto de Ciencias del Cosmos (ICCUB), MDM-2014-0369, Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Lena, D. [0000-0003-4184-6152], Loiseau, N. [0000-0001-5471-3776], Haiman, Z. [0000-0003-3633-5403], De Rosa, A. [0000-0001-5668-6863], Husemann, B. [0000-0003-2901-6842], Agenzia Spaziale Italiana (ASI), Istituto Nazionale Astrofisica (INAF), National Aeronautics and Space Administration (NASA), Hungarian Scientific Research Fund (OTKA), Hungarian Academy of Sciences (MTA), Deutsche Forschungsgemeinschaft (DFG), European Union COFUND/Durham Junior Research Fellowship (EU), European Research Council (ERC), Swiss National Science Foundation (SNSF), Federal Ministry of Education & Research (BMBF), Ministerio de Economía y Competitividad (MINECO), Comunidad de Madrid, Agencia Estatal de Investigación (AEI), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Agenzia Spaziale Italiana, National Aeronautics and Space Administration (US), Hungarian Academy of Sciences, National Research, Development and Innovation Office (Hungary), German Research Foundation, European Commission, European Research Council, Ministerio de Economía y Competitividad (España), Swiss National Science Foundation, National Science Foundation (US), Hungarian National Research, New National Excellence Program of the Ministry for Innovation and Technology, Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, Centro de Excelencia Científica Severo Ochoa Instituto de Astrofísica de Andalucía CSIC, Unidad de Excelencia Científica María de Maeztu Instituto de Ciencias del Coscmos de la Universidad de Barcelona, 'Programa de Atraccion de Talento' of the Comunidad de Madrid, 2018-T1/TIC-11733, De Rosa, A, Vignali, C, Bogdanovic, T, Capelo, P, Charisi, M, Dotti, M, Husemann, B, Lusso, E, Mayer, L, Paragi, Z, Runnoe, J, Sesana, A, Steinborn, L, Bianchi, S, Colpi, M, del Valle, L, Frey, S, Gabanyi, K, Giustini, M, Guainazzi, M, Haiman, Z, Herrera Ruiz, N, Herrero-Illana, R, Iwasawa, K, Komossa, S, Lena, D, Loiseau, N, Perez-Torres, M, Piconcelli, E, Volonteri, M, Rosa, Alessandra De, Vignali, Cristian, Bogdanović, Tamara, Capelo, Pedro R., Charisi, Maria, Dotti, Massimo, Husemann, Bernd, Lusso, Elisabeta, Mayer, Lucio, Paragi, Zsolt, Runnoe, Jessie, Sesana, Alberto, Steinborn, Lisa, Bianchi, Stefano, Colpi, Monica, Valle, Luciano Del, Frey, Sándor, Gabányi, Krisztina É., Giustini, Margherita, Guainazzi, Matteo, Haiman, Zoltan, Ruiz, Noelia Herrera, Herrero-Illana, Rubén, Iwasawa, Kazushi, Komossa, S., Lena, Davide, Loiseau, Nora, Perez-Torres, Miguel, Piconcelli, Enrico, Volonteri, Marta, De Rosa A., Vignali C., Bogdanovic T., Capelo P.R., Charisi M., Dotti M., Husemann B., Lusso E., Mayer L., Paragi Z., Runnoe J., Sesana A., Steinborn L., Bianchi S., Colpi M., del Valle L., Frey S., Gabanyi K.E., Giustini M., Guainazzi M., Haiman Z., Herrera Ruiz N., Herrero-Illana R., Iwasawa K., Komossa S., Lena D., Loiseau N., Perez-Torres M., Piconcelli E., and Volonteri M.
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Galaxies: active ,Galaxies: interactions ,Galaxies: nuclei ,gravitational waves ,Quasars: supermassive black holes ,Active galactic nucleus ,active [Galaxies] ,Electromagnetic spectrum ,Astrophysics::High Energy Astrophysical Phenomena ,Nuclear Theory ,Binary number ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,interactions [Galaxies] ,01 natural sciences ,7. Clean energy ,Cosmology ,Gravitational waves ,General Relativity and Quantum Cosmology ,0103 physical sciences ,010303 astronomy & astrophysics ,gravitational wave ,Astrophysics::Galaxy Astrophysics ,Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Supermassive black hole ,010308 nuclear & particles physics ,Gravitational wave ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Redshift ,13. Climate action ,Space and Planetary Science ,Galaxies: interaction ,Astrophysics of Galaxies (astro-ph.GA) ,nuclei [Galaxies] ,Astrophysics - High Energy Astrophysical Phenomena ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,supermassive black holes [Quasars] - Abstract
69 pages, 21 figures. Accepted for publication in New Astronomy Reviews © 2020 Elsevier B.V., The quest for binary and dual supermassive black holes (SMBHs) at the dawn of the multi-messenger era is compelling. Detecting dual active galactic nuclei (AGN) -- active SMBHs at projected separations larger than several parsecs -- and binary AGN -- probing the scale where SMBHs are bound in a Keplerian binary -- is an observational challenge. The study of AGN pairs (either dual or binary) also represents an overarching theoretical problem in cosmology and astrophysics. The AGN triggering calls for detailed knowledge of the hydrodynamical conditions of gas in the imminent surroundings of the SMBHs and, at the same time, their duality calls for detailed knowledge on how galaxies assemble through major and minor mergers and grow fed by matter along the filaments of the cosmic web. This review describes the techniques used across the electromagnetic spectrum to detect dual and binary AGN candidates and proposes new avenues for their search. The current observational status is compared with the state-of-the-art numerical simulations and models for formation of dual and binary AGN. Binary SMBHs are among the loudest sources of gravitational waves (GWs) in the Universe. The search for a background of GWs at nHz frequencies from inspiralling SMBHs at low redshifts, and the direct detection of signals from their coalescence by the Laser Interferometer Space Antenna in the next decade, make this a theme of major interest for multi-messenger astrophysics. This review discusses the future facilities and observational strategies that are likely to significantly advance this fascinating field.© 2020 Elsevier B.V., All authors acknowledge the hospitality of the Lorentz Center for international workshops (Leiden, The Netherlands), where the idea of this work was born, and acknowledge the support of the International Space Science Institute (ISSI Bern, Switzerland), where the collaboration was originated. We thank the reviewers for having provided valuable and constructive comments that improved the clarity of the manuscript, and J.E. Barnes, L. Blecha, M. Eracleous, B.D. Farris, H. Fu, X. Liu, R. Pfeifle, L.C. Popovic, C. Ricci, S. Rodriguez, S. Tang, G. B. Taylor for their kind permission to reuse figures from their publications. ADR, CV and SB acknowledge financial support from ASI under grant ASI-INAF I/037/12/0 , and from the agreement ASI-INAF n. 2017-14-H.O . TB acknowledges support by the National Aeronautics and Space Administration under Grant No. NNX15AK84G and 80NSSC19K0319 issued through the Astrophysics Theory Program and by the Research Corporation for Science Advancement through a Cottrell Scholar Award. SF and KÉG thank the Hungarian National Research, Development, and Innovation Office ( OTKA NN110333 ) for support. KÉG was supported by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences and by the ÚNKP-19-4 New National Excellence Program of the Ministry for Innovation and Technology. BH acknowledges financial support by the DFG grant GE625/17-1 . EL is supported by a European Union COFUND/Durham Junior Research Fellowship (under EU grant agreement no. 609412). DL acknowledges support from the European Research Council (ERC) under grant 647208 (PI Jonker). AS is supported by the ERC CoG grant 818691 (B Massive). MGi is supported by the “Programa de Atracción de Talento” of the Comunidad de Madrid grant 2018-T1/TIC-11733 for the project: “Unveiling Black Hole Winds from Space”, and by the Spanish State Research Agency (AEI) grant MDM-2017-0737 Unidad de Excelencia “María de Maeztu” - Centro de Astrobiología (INTA-CSIC). PRC and LM acknowledge support from the Swiss National Science Foundation under the Grant 200020_178949 . MC acknowledges support from the National Science Foundation (NSF) NANOGrav Physics Frontier Center, award number 1430284 . NHR acknowledges support from the BMBF Verbundforschung under FKZ: 05A17PC1 and FKZ: 05A17PC2. ZH acknowledges support from NASA grants NNX17AL82G and 80NSSC19K0149 and NSF grant 1715661 . KI acknowledges support by the Spanish MINECO under grant AYA2016-76012-C3-1-P and MDM-2014-0369 of ICCUB (Unidad de Excelencia ’María de Maeztu’). MPT acknowledges financial support from the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía ( SEV-2017-0709 ) and through the MINECO grants AYA2012-38491-C02-02 and AYA2015-63939-C2-1-P .
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- 2019
15. Detrital Tourmalines in the Cretaceous–Eocene Julian and Brkini Flysch Basins (SE Alps, Italy and Slovenia)
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Davide Lenaz, Giovanna Garlatti, Francesco Bernardi, and Sergio Andò
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heavy mineral assemblage ,tourmaline ,flysch basins ,Cretaceous–Eocene ,Italy ,Slovenia ,Mineralogy ,QE351-399.2 - Abstract
In the SE Alps, two Cretaceous–Eocene flysch basins, Julian and Brkini, filled with turbidite sediments, are present. This study novelly reports heavy mineral assemblage counts and detrital tourmaline characterization for 11 samples. It is possible to define three different groups, characterized by the presence of (1) a clinopyroxene–epidote–low-ZTR (zircon+tourmaline+rutile; 5%) sample association, (2) a high-ZTR (>48%)–garnet–apatite association and (3) a low-ZTR (
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- 2024
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16. Live Demonstration of Portable Systems based on Silicon Sensors for the monitoring of Physiological Parameters of Driver Drowsiness and Pulse Wave Velocity
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Francesco Rundo, Giorgio Fallica, Sabrina Conoci, Danilo Demarchi, Irene Buraioli, and Davide Lena
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Signal processing ,PWV ,Computer science ,SiPM ,020209 energy ,Acoustics ,020208 electrical & electronic engineering ,Feature extraction ,Biomedical Engineering ,Health Informatics ,02 engineering and technology ,Signal ,Silicon photomultiplier ,Photoplethysmogram ,Signal Processing ,0202 electrical engineering, electronic engineering, information engineering ,PPG ,Electrical and Electronic Engineering ,Instrumentation ,Instrumentation (computer programming) ,Optical filter ,Pulse wave velocity - Abstract
In this paper we present a PHYSIO-Sensor based on STM proprietary technology able to accurately reconstruct in a portable format both the PPG (PhotoPlethysmoGraphy) signal and Pulse Wave Velocity (PWV).
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- 2018
17. Training a classifier for activity recognition using body motion simulation
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Danilo Demarchi, Michelangelo Grosso, Davide Lena, Salvatore Rinaudo, and D. A. Fernandez Guzman
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Motion simulation ,Computer science ,business.industry ,Supervised learning ,Wearable computer ,Experimental data ,Accelerometer ,Machine learning ,computer.software_genre ,Activity recognition ,Artificial intelligence ,business ,Classifier (UML) ,computer - Abstract
Classification of human activity is an increasingly popular topic, as it is employed in various fields from fitness to remote health monitoring. Current automated approaches based on wearable sensors typically use supervised learning methodologies, where a classifier is trained with experimental data. This paper proposes the use of body motion and sensor simulation for building, or extending, the training databases and improve the classifier accuracy, without requiring further experimental campaigns.
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- 2018
18. An accurate electro-thermal model of SiC power MOSFETs for fast simulations
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Danilo Demarchi, Irene Buraioli, Davide Lena, Alberto Bocca, and Alberto Macii
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010302 applied physics ,Computer science ,020208 electrical & electronic engineering ,Semiconductor device modeling ,third quadrant characteristics ,Mixed-signal integrated circuit ,02 engineering and technology ,SiC modeling ,01 natural sciences ,CAD methodologies ,Electric power system ,chemistry.chemical_compound ,chemistry ,0103 physical sciences ,MOSFET ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Silicon carbide ,Inverter ,discrete power device ,Power semiconductor device ,wide bandgap device ,Power MOSFET - Abstract
A methodology for developing an electro-thermal model for silicon carbide (SiC) power transistors, is presented. The primary target of a such methodology is to address a detailed system level mixed signal multi-domain simulation, where simulation time and accuracy are the key factors. The adopted methodology aims to provide a compact model usable in a high-level behavioral description of any SiC-based power system. The modeling of an existing SiC MOSFET produced by STM is then described as an application. A preliminary simulation was carried out to compare the results to real device characteristics. A scenario of an inverter circuit based on SiC power transistors is also provided. Using the proposed macromodel, the final results show a reduction in simulation time of the inverter by a factor of 40 with respect to the original PSpice simulation time.
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- 2018
19. Dusty spirals versus gas kinematics in the inner kiloparsec of Four Low-Luminosity Active Galactic Nuclei
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Rogemar A. Riffel, Allan Schnorr Müller, Carine Brum, Thaisa Storchi-Bergmann, Davide Lena, and Andrew Robinson
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individual (NGC 4501) [Galaxies] ,Seyfert [Galaxies] ,Active galactic nucleus ,Astronomy ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Gas ionizado ,Disc galaxy ,Lambda ,01 natural sciences ,Hubble sequence ,symbols.namesake ,0103 physical sciences ,Cinemática ,Disc ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Mapeamentos astronômicos ,Physics ,Luminous infrared galaxy ,kinematics and dynamics [Galaxies] ,010308 nuclear & particles physics ,individual (NGC 4450) [Galaxies] ,Astronomy and Astrophysics ,Espectros estelares ,Astrophysics - Astrophysics of Galaxies ,Galaxias seyfert ,Galaxy ,individual (NGC 2787) [Galaxies] ,individual (NGC 3982) [Galaxies] ,Supernova ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,symbols ,Nucleo galatico - Abstract
We used the Gemini Multi-Object Spectrograph Integral Field Unit to map the gas distribution, excitation and kinematics within the inner kiloparsec of four nearby low-luminosity active galaxies: NGC3982, NGC4501, NGC2787 and NGC4450. The observations cover the spectral range 5600-7000{\AA} at a velocity resolution of 120km/s and spatial resolution ranging from 50 to 70pc at the galaxies. Extended emission in H{\alpha}, [NII]{\lambda}{\lambda}6548,6583, [SII]{\lambda}{\lambda}6716,6730 over most of the field-of-view is observed for all galaxies, while only NGC3982 shows [OI]{\lambda}6300 extended emission. The H{\alpha} equivalent widths combined with the [NII]/H{\alpha} line ratios reveal that NGC3982 and NGC4450 harbor Seyfert nuclei surrounded by regions with LINER excitation, while NGC2787 and NGC4501 harbor LINER nuclei. NGC3982 shows a partial ring of recent star-formation at 500pc from the nucleus, while in NGC4501 a region at 500pc west of the nucleus shows LINER excitation but has been interpreted as an aging HII region with the gas excitation dominated by shocks from supernovae. The line-of-sight velocity field of the gas shows a rotation pattern for all galaxies, with deviations from pure disk rotation observed in NGC3982, NGC4501 and NGC4450. For NGC4501 and NGC4450, many of these deviations are spatially coincident with dust structures seen in optical continuum images, leading to the interpretation that the deviations are due to shocks in the gas traced by the dust. A speculation is that these shocks lead to loss of angular momentum, allowing the gas to be transferred inwards to feed the AGN. In the case of NGC2787, instead of deviations in the rotation field, we see a misalignment of 40{^\circ} between the orientation of the line of nodes of the gas rotation and the photometric major axis of the galaxy. Evidence of compact nuclear outflows are seen in NGC4501 and NGC4450., Comment: 20 pages, accepted for publication in MNRAS
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- 2017
20. Gas inflows towards the nucleus of NGC 1358
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Andrew Robinson, Thaisa Storchi-Bergmann, Allan Schnorr-Müller, Neil M. Nagar, and Davide Lena
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Active galactic nucleus ,Galáxia NGC 1358 ,active [Galaxies] ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Rotation ,01 natural sciences ,Integral field spectrograph ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Cinemática ,Emission spectrum ,individual: NGC1358 [Galaxies] ,010303 astronomy & astrophysics ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) ,Astrophysics::Galaxy Astrophysics ,Physics ,Spiral galaxy ,010308 nuclear & particles physics ,kinematics and dynamics [Galaxies] ,seyfert [Galaxies] ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Galaxias seyfert ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,nuclei [Galaxies] ,Vector field ,Outflow ,Nucleo galatico - Abstract
We use optical spectra from the inner 1.8 $\times$ 2.5kpc$^2$ of the Seyfert 2 galaxy NGC1358, obtained with the GMOS integral field spectrograph on the Gemini South telescope at a spatial resolution of $\approx$ 165pc, to assess the feeding and feedback processes in this nearby active galaxy. Five gaseous kinematical components are observed in the emission line profiles. One of the components is present in the entire field-of-view and we interpret it as due to gas rotating in the disk of the galaxy. Three of the remaining components we interpret as associated to active galactic nucleus (AGN) feedback: a compact unresolved outflow in the inner 1 arcsec and two gas clouds observed at opposite sides of the nucleus, which we propose have been ejected in a previous AGN burst. The disk component velocity field is strongly disturbed by a large scale bar. The subtraction of a velocity model combining both rotation and bar flows reveals three kinematic nuclear spiral arms: two in inflow and one in outflow. We estimate the mass inflow rate in the inner 180pc obtaining $\dot{M}_{in}$ $\approx$ 1.5 $\times 10^{-2}$M$_{\odot}$yr$^{-1}$, about 160 times larger than the accretion rate necessary to power this AGN., 12 pages, 11 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society. arXiv admin note: text overlap with arXiv:1701.00865
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- 2017
21. Energy-efficient battery charging in electric vehicles with solar panels
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Alberto Macii, Michelangelo Grosso, Davide Lena, Salvatore Rinaudo, and Alberto Bocca
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Engineering ,business.product_category ,business.industry ,020209 energy ,020208 electrical & electronic engineering ,Photovoltaic system ,electric vehicle ,photovoltaic panels ,Electrical engineering ,cell balancing ,Battery charging ,02 engineering and technology ,Solar energy ,Automotive engineering ,Photovoltaic thermal hybrid solar collector ,State of charge ,Electric vehicle ,Solar vehicle ,0202 electrical engineering, electronic engineering, information engineering ,Grid-connected photovoltaic power system ,ComputerSystemsOrganization_SPECIAL-PURPOSEANDAPPLICATION-BASEDSYSTEMS ,Solar cable ,business - Abstract
The problem of pollution due to transportation is extremely serious. Hybrid and fully electric vehicles are increasingly popular, to reduce fuel consumption and gas emissions, and car makers are also starting to equip vehicles with solar panels to extend driving range. These photovoltaic installations pose many challenges, e.g., how to increase their efficiency and decide where and how the solar energy is stored. This paper analyzes the problem of transferring the energy generated by an on-board solar cell system to the main battery pack of an electric vehicle and proposes an optimized solution based on the interaction with the BMS.
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- 2016
22. DIMCloud – a distributed infrastructure for district energy management
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Brundu, FRANCESCO GAVINO, Patti, Edoardo, Acquaviva, Andrea, Grosso, Michelangelo, Gaetano, Rasconà, Davide, Lena, Salvatore, Rinaudo, Ronzino, Amos, Osello, Anna, Macii, Enrico, BRUNDU, FRANCESCO GAVINO, PATTI, EDOARDO, ACQUAVIVA, ANDREA, GROSSO, MICHELANGELO, Gaetano Rasconà, Davide Lena, Salvatore Rinaudo, RONZINO, AMOS, OSELLO, Anna, and MACII, Enrico
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Middleware ,smart city ,Ontology ,district ,ubiquitous computing ,pervasive computing ,Internet of Things (IoT) ,smart grid ,data integration ,User Profiling - Abstract
The application of Information and Communications Technologies (ICT) is a key element to increase the energy efficiency of buildings and districts. With ICTs it is possible to monitor the entire energy transfer between producer and consumer, to profile end users and to promote their awareness with regards to their energy consumption. For instance, advanced visualization technologies, such as Augmented Reality, can provide a real-time feedback to users about their energy use behaviors. Moreover, statistical analyses on population energy profiles will allow energy providers to better schedule the energy distribution at different timings, to increase demand response. Finally, environmental conditions and user feedback data will have a direct role to lead the autonomous control of energy use at the district, building, or even at the apartment level. Unfortunately, to build a coherent information system is often more difficult than to collect and analyze data. Indeed, the main components of such infrastructure are usually difficult to integrate together, because they can be realized with heterogeneous technologies. Furthermore, data format is often specific to each platform and often it is not portable. Moreover, data can be stored using different technologies and it can be maintained in different locations. In this scenario, the lack of an unifying paradigm is a major issue and enabling the interoperability between heterogeneous technologies is the key challenge. The proposed District Information Model Cloud (DIMCloud) is a distributed infrastructure, which targets to make a cloud digital archive for energy management in the district. The whole DIMCloud exploits a service-oriented middleware approach to enable the interoperability across heterogeneous hardware and software technologies. It aims to collect environmental information coming from pervasive and heterogeneous systems deployed in buildings and energy distribution networks in the district. Internet-of-things devices play a key role in this framework, enabling the collection of fine-grained environmental information. To be effective in the specific application, a number of requirements must be accounted for, such as network reliability and self-configuration, wireless transmission range, band regulations compliancy and low energy consumption. In addition, DIMCloud shares georeferenced structural characteristics and parameters about both buildings (BIM) and energy distribution networks providing also their virtual models. It offers a web query interface, where data of a specific district, building or device can be retrieved, and experimental low-energy sensor networks. Subsequently, data is provided encoded in JSON, a human-readable semistructured data format. Finally, this information can be accessed and exploited to: i) profile the energy consumption from the district point of view down to the single building; ii) design more efficient control policies; iii) increase energy user awareness.
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- 2014
23. Integral Field Spectroscopy of the circumnuclear region of the Radio Galaxy Pictor A
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Guilherme S. Couto, A. Schnorr-Müller, Rogemar A. Riffel, Davide Lena, Preeti Kharb, Andrew Robinson, and Thaisa Storchi-Bergmann
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Radio galaxy ,Astronomy ,Metallicity ,media_common.quotation_subject ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,0103 physical sciences ,medicine ,010303 astronomy & astrophysics ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) ,Astrophysics::Galaxy Astrophysics ,media_common ,Line (formation) ,Physics ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Redshift ,Galaxy ,medicine.anatomical_structure ,Space and Planetary Science ,Sky ,Astrophysics of Galaxies (astro-ph.GA) ,Vector field ,Nucleus - Abstract
We present optical integral field spectroscopy of the inner $2.5 \times 3.4$ kpc$^2$ of the broad-line radio galaxy Pictor A, at a spatial resolution of $\approx 400$ pc. Line emission is observed over the whole field-of-view, being strongest at the nucleus and in an elongated linear feature (ELF) crossing the nucleus from the south-west to the north-east along PA $\sim 70^\circ$. Although the broad double-peaked H$\alpha$ line and the [OI]6300/H$\alpha$ and [SII]6717+31/H$\alpha$ ratios are typical of AGNs, the [NII]6584/H$\alpha$ ratio (0.15 - 0.25) is unusually low. We suggest that this is due to the unusually low metallicity of the gas. Centroid velocity maps show mostly blueshifts to the south and redshifts to the north of the nucleus, but the velocity field is not well fitted by a rotation model. Velocity dispersions are low (< 100 km s$^{-1}$) along the ELF, ruling out a jet-cloud interaction as the origin of this structure. The ELF shows both blueshifts and redshifts in channel maps, suggesting that it is close to the plane of the sky. The ELF is evidently photoionized by the AGN, but its kinematics and inferred low metallicity suggest that this structure may have originated in a past merger event with another galaxy. We suggest that the gas acquired in this interaction may be feeding the ELF., Comment: 15 pages, 10 figures, 1 table; accepted for publication in MNRAS
- Published
- 2016
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24. Ionized gas kinematics within the inner kiloparsec of the Seyfert galaxy NGC 1365
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Rogemar A. Riffel, Thaisa Storchi-Bergmann, Andrew Robinson, A. Schnorr-Müller, Guilherme S. Couto, and Davide Lena
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Angular momentum ,active [Galaxies] ,Field (physics) ,Astronomy ,Astrophysics::High Energy Astrophysical Phenomena ,media_common.quotation_subject ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Gas ionizado ,Rotation ,01 natural sciences ,Asymmetry ,0103 physical sciences ,Cinemática ,Emission spectrum ,Spectral resolution ,010303 astronomy & astrophysics ,Galáxia NGC 1365 ,Astrophysics::Galaxy Astrophysics ,media_common ,Physics ,individual: NGC 1365 [Galaxies] ,kinematics and dynamics [Galaxies] ,010308 nuclear & particles physics ,seyfert [Galaxies] ,Astronomy and Astrophysics ,Black hole physics ,Astrophysics - Astrophysics of Galaxies ,Galaxias seyfert ,Galaxy ,Space and Planetary Science ,nuclei [Galaxies] ,Astrophysics of Galaxies (astro-ph.GA) ,ComputingMethodologies_DOCUMENTANDTEXTPROCESSING ,Lindblad resonance ,Nucleo galatico - Abstract
We observed the nuclear region of the galaxy NGC 1365 with the integral field unit of the Gemini Multi Object Spectrograph mounted on the GEMINI-South telescope. The field of view covers $13^{\prime\prime} \times 6^{\prime\prime}$ ($1173 \times 541$ pc$^{2}$) centered on the nucleus, at a spatial resolution of $52$ pc. The spectral coverage extends from $5600$ \AA\ to $7000$ \AA, at a spectral resolution $R=1918$. NGC 1365 hosts a Seyfert 1.8 nucleus, and exhibits a prominent bar extending out to $100^{\prime\prime}$ (9 kpc) from the nucleus. The field of view lies within the inner Lindblad resonance. Within this region, we found that the kinematics of the ionized gas (as traced by [OI], [NII], H$\alpha$, and [SII]) is consistent with rotation in the large-scale plane of the galaxy. While rotation dominates the kinematics, there is also evidence for a fan-shaped outflow, as found in other studies based on the [OIII] emission lines. Although evidence for gas inflowing along nuclear spirals has been found in a few barred galaxies, we find no obvious signs of such features in the inner kiloparsec of NGC 1365. However, the emission lines exhibit a puzzling asymmetry that could originate from gas which is slower than the gas responsible for the bulk of the narrow-line emission. We speculate that it could be tracing gas which lost angular momentum, and is slowly migrating from the inner Lindblad resonance towards the nucleus of the galaxy., Comment: Accepted for publication on MNRAS
- Published
- 2016
25. A compact IGBT electro-thermal model in Verilog-A for fast system-level simulation
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Alberto Bocca, Alberto Macii, Davide Lena, Salvatore Rinaudo, and Michelangelo Grosso
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Engineering ,Work (thermodynamics) ,02 engineering and technology ,01 natural sciences ,CAD methodologies ,Verilog-A ,0103 physical sciences ,Thermal ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,discrete power device ,Thermal analysis ,IGBT modeling ,IPEM, IPM ,Simulation ,010302 applied physics ,business.industry ,020208 electrical & electronic engineering ,Mixed-signal integrated circuit ,System-level simulation ,Insulated-gate bipolar transistor ,IPEM ,Key (cryptography) ,Inverter ,IPM ,business - Abstract
In this work, the implementation of a compact electro-thermal model of a trench gate field-stop IGBT device is presented. The primary target is to address system-level mixed signal multi-domain simulation where the simulation time is a key factor for the usefulness of results. The methodology adopted provides a model suitable for use on both SPICE-only simulators, where thermal behavior is mapped to electrical quantities, and on a multi-domain environment, where heterogeneous physical domains are managed by a simulation engine. A comparison with real device characteristics is presented to show model accuracy and finally a simulation of an inverter circuit is investigated to highlight achievable performances.
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- 2016
26. The complex gas kinematics in the nucleus of the Seyfert 2 galaxy NGC 1386: rotation, outflows and inflows
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Neil M. Nagar, Guilherme S. Couto, T. Seelig, T. Storchi-Bergman, L. Shadler, Davide Lena, Andrew Robinson, Rogemar A. Riffel, and A. Schnorr-Müller
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Physics ,Active galactic nucleus ,010308 nuclear & particles physics ,Radio galaxy ,Velocity dispersion ,FOS: Physical sciences ,Astronomy and Astrophysics ,Quasar ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Redshift ,Space and Planetary Science ,Bipolar outflow ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,Outflow ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We present optical integral field spectroscopy of the circum-nuclear gas of the Seyfert 2 galaxy NGC 1386. The data cover the central 7$^{\prime\prime} \times 9^{\prime\prime}$ (530 $\times$ 680 pc) at a spatial resolution of 0.9" (68 pc), and the spectral range 5700-7000 \AA\ at a resolution of 66 km s$^{-1}$. The line emission is dominated by a bright central component, with two lobes extending $\approx$ 3$^{\prime\prime}$ north and south of the nucleus. We identify three main kinematic components. The first has low velocity dispersion ($\bar \sigma \approx $ 90 km s$^{-1}$), extends over the whole field-of-view, and has a velocity field consistent with gas rotating in the galaxy disk. We interpret the lobes as resulting from photoionization of disk gas in regions where the AGN radiation cones intercept the disk. The second has higher velocity dispersion ($\bar \sigma \approx$ 200 km s$^{-1}$) and is observed in the inner 150 pc around the continuum peak. This component is double peaked, with redshifted and blueshifted components separated by $\approx$ 500 km s$^{-1}$. Together with previous HST imaging, these features suggest the presence of a bipolar outflow for which we estimate a mass outflow rate of $\mathrm{\dot M} \gtrsim $ 0.1 M$_{\odot}$ yr$^{-1}$. The third component is revealed by velocity residuals associated with enhanced velocity dispersion and suggests that outflow and/or rotation is occurring approximately in the equatorial plane of the torus. A second system of velocity residuals may indicate the presence of streaming motions along dusty spirals in the disk., Comment: 24 pages, 16 figures, 3 tables, interesting results, accepted for publication in ApJ
- Published
- 2015
27. Calibration and characterization of MEMS microphones
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Andrea Prato, Irene Buraioli, Alessandro Schiavi, Davide Lena, and Danilo Demarchi
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Microelectromechanical systems ,Frequency response ,Noise ,Acoustics and Ultrasonics ,Arts and Humanities (miscellaneous) ,Dynamic range ,Measurement microphone calibration ,Computer science ,Microphone ,ComputerSystemsOrganization_MISCELLANEOUS ,Acoustics ,Calibration ,Sensitivity (electronics) - Abstract
In recent years, the increase in the number of smartphones led to a remarkable demand for low-cost microphones. This was met by the rapid development of MEMS (MicroElectroMechanical Systems) microphones, whose technology is becoming a promising perspective for future noise measurements based on new acoustic sensor networks. Nevertheless, current Standards do not provide proper calibration and test procedures for these microphones. In this work, calibration standard procedures have been adapted to characterize condenser MEMS microphones by comparison technique with laboratory standard microphones. Microphone parameters (sensitivity, frequency response, linearity, directivity, stability, and dynamic range) and changes of sensitivity with temperature (from -10 °C to + 50 °C) and humidity (from 25% to 90%) have been evaluated in a hemi-anechoic room and in an environmental chamber, respectively. These procedures open up the possibility to provide a robust and metrological characterization of MEMS microphones for noise measurements.
- Published
- 2017
28. Feeding and Feedback in the Inner Kiloparsec of the Active Galaxy NGC2110
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Rogemar A. Riffel, Allan Schnorr-Müller, Thaisa Storchi-Bergmann, Davide Lena, Andrew Robinson, Neil M. Nagar, and Guilherme S. Couto
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Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Active galactic nucleus ,active [Galaxies] ,Doubly ionized oxygen ,FOS: Physical sciences ,Inflow ,Astrophysics ,Espectros astronômicos ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Deslocamento para o vermelho ,Astrophysics::Galaxy Astrophysics ,Physics ,Spiral galaxy ,kinematics and dynamics [Galaxies] ,seyfert [Galaxies] ,Velocity dispersion ,Astronomy ,Astronomy and Astrophysics ,Galaxy ,Redshift ,Galaxias seyfert ,Space and Planetary Science ,nuclei [Galaxies] ,individual: NGC 2110 [Galaxies] ,Outflow ,Fotoionizacao ,Nucleo galatico ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present two-dimensional gaseous kinematics of the inner 1.1 x 1.6kpc^2 of the Seyfert 2 galaxy NGC2110, from optical spectra obtained with the GMOS integral field spectrograph on the Gemini South telescope at a spatial resolution of 100pc. Gas emission is observed over the whole field-of-view, with complex - and frequently double - emission-line profiles. We have identified four components in the emitting gas, according to their velocity dispersion (sigma), which we refer to as: (1) warm gas disk (sigma = 100-220km/s); (2) cold gas disk (sigma = 60-90km/s); (3) nuclear component (sigma = 220-600km/s); and (4) northern cloud (sigma = 60-80km/s). Both the cold and warm disk components are dominated by rotation and have similar gas densities, but the cold gas disk has lower velocity dispersions and reaches higher rotation velocities. We attribute the warm gas disk to a thick gas layer which encompasses the cold disk as observed in some edge-on spiral galaxies. After subtraction of a rotation model from the cold disk velocity field, we observe excess blueshifts of 50km/s in the far side of the galaxy as well as similar excess redshifts in the near side. These residuals can be interpreted as due to nuclear inflow in the cold gas, with an estimated ionized gas mass inflow rate of 2.2 x 10^(-2)Msun/yr. We have also subtracted a rotating model from the warm disk velocity field and found excess blueshifts of 100km/s to the SW of the nucleus and excess redshifts of 40km/s to the NE, which we attribute to gas disturbed by an interaction with a nuclear spherical outflow. This nuclear outflow is the origin of the nuclear component observed within the inner 300pc and it has a mass outflow rate of 0.9Msun/yr. In a region between 1" and 4" north of the nucleus we find a new low sigma component of ionized gas which we attribute to a high latitude cloud photoionized by the nuclear source., 17 pages, 13 figures, 1 table; accepted for publication in MNRAS
- Published
- 2013
29. Correction: Bernardi et al. OH-Defects in Detrital Quartz Grains from the Julian Basin (NE Italy and Slovenia): A Fourier Transform Infrared Study. Geosciences 2022, 12, 90
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Francesco Bernardi, Henrik Skogby, and Davide Lenaz
- Subjects
n/a ,Geology ,QE1-996.5 - Abstract
The authors would like to correct the published article [...]
- Published
- 2023
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30. RECOILING SUPERMASSIVE BLACK HOLES: A SEARCH IN THE NEARBY UNIVERSE
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David Merritt, David Axon, Andrew Robinson, Alessandro Marconi, Davide Lena, Dan Batcheldor, and A. Capetti
- Subjects
Physics ,Supermassive black hole ,Active galactic nucleus ,Gravitational wave ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Gravitation ,Recoil ,Binary black hole ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Binary star ,Astrophysics::Galaxy Astrophysics - Abstract
The coalescence of a binary black hole can be accompanied by a large gravitational recoil due to anisotropic emission of gravitational waves. A recoiling supermassive black hole (SBH) can subsequently undergo long-lived oscillations in the potential well of its host galaxy, suggesting that offset SBHs may be common in the cores of massive ellipticals. We have analyzed HST archival images of 14 nearby core ellipticals, finding evidence for small ($\lesssim 10$ pc) displacements between the AGN (locating the SBH) and the center of the galaxy (the mean photocenter) in 10 of them. Excluding objects that may be affected by large-scale isophotal asymmetries, we consider six galaxies to have detected displacements, including M87, where a displacement was previously reported by Batcheldor et al. 2010. In individual objects, these displacements can be attributed to residual gravitational recoil oscillations following a major or minor merger within the last few Gyr. For plausible merger rates, however, there is a high probability of larger displacements than those observed, if SBH coalescence took place in these galaxies. Remarkably, the AGN-photocenter displacements are approximately aligned with the radio source axis in four of the six galaxies with displacements, including three of the four having relatively powerful kpc-scale jets. This suggests intrinsic asymmetries in radio jet power as a possible displacement mechanism, although approximate alignments are also expected for gravitational recoil. Orbital motion in SBH binaries and interactions with massive perturbers can produce the observed displacement amplitudes but do not offer a ready explanation for the alignments., 58 pages, 32 figures, 9 tables. Accepted for publication in ApJ
- Published
- 2014
31. Portable X-ray Fluorescence (pXRF) as a Tool for Environmental Characterisation and Management of Mining Wastes: Benefits and Limits
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Nicolò Barago, Elena Pavoni, Federico Floreani, Matteo Crosera, Gianpiero Adami, Davide Lenaz, Francesca Larese Filon, and Stefano Covelli
- Subjects
portable X-ray fluorescence (pXRF) ,validation ,mining wastes ,contamination ,sample preparation ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Portable X-ray fluorescence (pXRF) is one of the main geochemical techniques employed in multi-elemental analysis screening for contaminated sites management. As the confidence of pXRF analyses are matrix-specific, efforts are made to provide studies of pXRF quality on different geochemical datasets, focusing on less investigated elements such as mercury (Hg) and antimony (Sb), to help both new and experienced users. The analysis of environmental solid samples from two decommissioned mining sites in NE Italy, characterised by Pb-Zn and (Hg-rich) Cu-Sb ore deposits, were prepared with two different protocols and compared with traditional destructive analyses. Sample composition was found strictly dependent to the occurrence of false positives and overestimation at low concentrations. In contrast, milling the sample did not produce major variations in the overall quality. Lead (Pb), Sb, and Zn reached the definitive data quality in at least one of the two datasets. Consequently, as far as a thorough QA/QC protocol is followed, pXRF can rapidly produce chemical data that is as accurate as that produced by destructive standard laboratory techniques, thus allowing to identify potential sources of contamination that could be reprocessed for the extraction of valuable elements and mitigating the dispersion of contaminants and ecological or health risks.
- Published
- 2022
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32. Trace Elements in Chromian Spinels from Four Siberian Kimberlites
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Marco Venier, Luca Ziberna, Francesco Princivalle, Maurizio Petrelli, Vanni Lughi, Alla Logvinova, Nikolay V. Sobolev, Gianluca Turco, and Davide Lenaz
- Subjects
trace elements ,Cr-spinel ,kimberlites ,Siberia ,Mineralogy ,QE351-399.2 - Abstract
We analysed the major, minor and trace elements chemistry of forty-two Cr-spinels from four Siberian kimberlites. They showed a wide range in Mg# (Mg/(Mg + Fe2+); 0.42–0.78) and Cr# (Cr/(Cr + Al); 0.32–0.92) and a common trend of increasing Cr# with decreasing Mg#. The major element classification schemes suggested that there were spinels deriving from a peridotitic source (Xen) and spinels crystallised from kimberlitic melts (Chr). Laser-Ablation Inductively Coupled Plasma Mass Spectrometry on both groups showed that the trace elements with the highest abundance were Mn (985–3390 ppm), Ni (531–3162 ppm), V (694–2510 ppm) and Zn (475–2230 ppm). Testing the effectiveness of trace elements in determining the source for Cr-spinels, we found out that Cr-spinels crystallised directly from a kimberlitic melt usually showed higher Mn, Ni, Sc and V concentrations with respect to those of peridotitic origin. In addition, using the available partitioning models, we found that the correlations between major elements and Ni, Co, Sc and Ga in the Xen group could be explained by subsolidus equilibration between spinel, olivine and clinopyroxene at 800–1000 °C, thus supporting a peridotitic source for this group. Finally, we calculated the composition of the possible melts in equilibrium with the Cr-spinels of the Chr group, using a selected set of partition coefficients. Calculated abundances of Cu, Ga and Zr were comparable to those of the kimberlite, while V was never close to the kimberlite composition. This simulation highlighted the need for new data on the trace elements partition coefficients between kimberlitic melts and Cr-spinel.
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- 2022
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33. Antarctic Salt-Cones: An Oasis of Microbial Life? The Example of Boulder Clay Glacier (Northern Victoria Land)
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Maurizio Azzaro, Maria Papale, Carmen Rizzo, Emanuele Forte, Davide Lenaz, Mauro Guglielmin, and Angelina Lo Giudice
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extremophiles ,salt cone ,mirabilite ,thenardite ,prokaryotic diversity ,supraglacial systems ,Biology (General) ,QH301-705.5 - Abstract
The evaporation of a localized, highly saline water body of the Boulder Clay debris-covered glacier, in the Northern Victoria Land, probably generated the accumulation of mirabilite (Na2SO4 × 10H2O) and thenardite (Na2SO4) in a glacier salt-cone. Such an extremely cold and salty environment resembles the conditions on Mars, so it can be considered a terrestrial analog. The study was aimed at gaining a first glimpse at the prokaryotic community associated with Antarctic mirabilite and thenardite minerals and also to find clues about the origin of the salts. For this purpose, samples were analyzed by a next generation approach to investigate the prokaryotic (Bacteria and Archaea) diversity. Phylogenetic analysis allowed the identification of Bacteroidota, Actinobacteriota, Firmicutes, and Gammaproteobacteria as the main bacterial lineages, in addition to Archaea in the phylum Halobacterota. The genera Arthrobacter, Rhodoglobus, Gillisia, Marinobacter and Psychrobacter were particularly abundant. Interestingly, several bacterial and archaeal sequences were related to halotolerant and halophilic genera, previously reported in a variety of marine environments and saline habitats, also in Antarctica. The analyzed salt community also included members that are believed to play a major role in the sulfur cycle.
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- 2022
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34. OH-Defects in Detrital Quartz Grains from the Julian Basin (NE Italy and Slovenia): A Fourier Transform Infrared Study
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Francesco Bernardi, Henrik Skogby, and Davide Lenaz
- Subjects
detrital quartz ,OH-defects ,Julian Basin ,Italy ,Slovenia ,Geology ,QE1-996.5 - Abstract
In this study, we analyzed up to 80 detrital quartz grains from four lithic greywackes along the stratigraphic column of the Julian Basin, a synorogenic basin in the southeastern Alps between Italy and Slovenia. Fourier transform infrared spectroscopy of detrital quartz was used to investigate the sample set with interest to its OH-defect speciation and content of each associated substitution. According to several recent studies, OH-defects in quartz are correlated to petrogenetic conditions of the source material and can be used as a provenance tool. The aim of this study is to compare results based on this method with previous studies that used other methods, to better constrain the palaeogeographical reconstruction of sedimentary fluxes. Detrital quartz within the samples of the basin shows different patterns of OH-defects and water content, indicating substantial petrogenetic differences between the sediment source rocks. For the oldest analyzed sample (ca. 66 Ma), the distribution of OH-defects suggests a mixed source between igneous and non-igneous rocks, with a predominance of metamorphic material supply. Another sample (56 Ma) reveals a great variability of OH-defects and water content, indicating that the magmatic component dominates over the metamorphic component. The distribution of OH-defects in the samples at the top of the sequence (52–53 Ma) suggests an almost solely metamorphic source. These results are in line with previous studies based on heavy minerals and geochemistry.
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- 2022
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35. The Österplana Fossil Meteorites and… What Else? Terrestrial Cr-Spinels and Zircons in the Ordovician Limestones of the Thorsberg Quarry (Sweden)
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Davide Lenaz, Matteo Velicogna, Maurizio Petrelli, and Birger Schmitz
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Cr-spinel ,zircon ,Ordovician ,Sweden ,Laurentia ,Baltica ,Geology ,QE1-996.5 - Abstract
In the Ordovician limestone of the Thorsberg quarry (South Sweden), about 130 meteorites have been found. Among the extraterrestrial material, several terrestrial Cr-spinels and zircons have been found too. In particular, in the interval 416–447 cm above the Arkeologen bed, terrestrial Cr-spinels, compositionally different from previous studied Cr-spinels of the same sequence, are present. Previous studies on zircon provided depositional ages that range from 464.22 ± 0.37 Ma to 465.01 ± 0.26 Ma. The trace element content of zircons suggests different possible source rocks. In fact, zircons from the oldest ash layer resemble those from dolerite, while those in the youngest layers are similar to zircons commonly found in granitoids, with more than 65% wt. SiO2. The chemistry of Cr-spinels suggests a strong alteration, so that it is difficult to assign them to a specific area, however they recall the chemistry of altered spinels from ophiolitic occurrences (among other possibilities). The geological setting of the Laurentia and Baltica areas, including the description of basalts to rhyolite association and the presence of ophiolitic slices, makes us confident about the derivation of these zircons and Cr-spinels from those areas.
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- 2022
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36. The Effects of High-Grade Metamorphism on Cr-Spinel from the Archean Sittampundi Complex, South India
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Davide Lenaz, Bidyananda Maibam, Jacob Adetunji, and Henrik Skogby
- Subjects
Cr-spinels ,high-grade metamorphism ,structural refinement ,Mössbauer spectroscopy ,Sittampundi ,India ,Mineralogy ,QE351-399.2 - Abstract
We investigated the crystal and structural behavior of Cr-bearing spinels from the Archean chromitites of Sittampundi (India), which had been subjected to very high-grade metamorphism. The structural data show that their oxygen positional parameters are among the highest ever recorded for Cr-bearing spinels with similar Cr# and Mg# and very similar to those found for other Archean occurrences. The general agreement between electron microprobe and Mössbauer data indicates that the analyzed spinels are stoichiometric. It is therefore most likely that the PH2O and Ptotal values as well as both the oxygen fugacity and the temperature reached during high-grade metamorphism inhibited the possibility of the non-stoichiometry of chromites, contrary to what can happen in ophiolites, where non-stoichiometry has recently been documented.
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- 2021
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37. Mineralogical and Geotechnical Characterization of the Clay Layers within the Basal Shear Zone of the 1963 Vajont Landslide
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Alberto Bolla, Paolo Paronuzzi, Daniela Pinto, Davide Lenaz, and Marco Del Fabbro
- Subjects
Vajont landslide ,large rockslide ,shear zone ,Fonzaso Formation ,clay ,illite/smectite mixed layer ,Geology ,QE1-996.5 - Abstract
The 1963 Vajont landslide is a reference example of large rockslides involving clay interbeds emplaced in sedimentary rock masses in correspondence with the basal rupture zone (thinly stratified cherty limestone of the Fonzaso Formation dated to Middle–Upper Jurassic). The basal shear zone of the 1963 Vajont landslide was made up of a chaotic assemblage of displaced rock masses, limestone angular gravel, and spread clay lenses. The mineralogical investigations showed that the clays are characterized by complex assemblages of illite/smectite mixed layers (36–96%) admixed with variable amounts of calcite (4–64%) and quartz (0–6%). The clay layers show highly variable plasticity properties and shear strength characteristics. The samples with a large prevalence of clay mineral content (CM) (CM > 79%) are characterized by low values of the residual friction angle (6.7–14.9°), whereas clay materials characterized by a higher content of granular minerals (calcite and quartz) clearly show greater friction angle values (19.5–26.7°). The high permeability of the limestone angular gravel, which caused a rapid reservoir-induced inflow (1960–1963), together with the low friction angle of the clay layers were responsible for the overall shear strength reduction in correspondence with the basal rupture zone, thus favoring the huge sliding on 9 October 1963.
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- 2020
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38. Evaporite Dissolution Rate through an on-site Experiment into Piezometric Tubes Applied to the Real Case-Study of Quinis (NE Italy)
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Chiara Calligaris, Lisa Ghezzi, Riccardo Petrini, Davide Lenaz, and Luca Zini
- Subjects
sinkholes ,karst ,geochemical analyses ,hydrogeology ,evaporite dissolution ,gypsum ,Geology ,QE1-996.5 - Abstract
The present paper deals with a field experiments on evaporite rock samples and groundwater investigations in the Quinis test site, a hamlet of the Enemonzo municipality in NE Italy, were sinkholes occurred in the past and are still occurring causing severe damage to the existing infrastructures. The area is characterised by a Carnian evaporitic bedrock made of gypsum and anhydrite mantled by alluvial and colluvial deposits. In order to evaluate the loss of weight and volume of the subcropping evaporites as responsible for sinkholes, a field-experiment was carried out. Inside seven piezometers, at different depths, evaporitic rock samples were exposed to the naturally occurring variable climatic conditions such as degree of humidity, different air flow and hydrodynamic. The rock samples were installed at the beginning of April 2017 in the dry sections of piezometric tubes, in the vadose zone and in the phreatic zone. Data related to water level fluctuations were recorded by using data-logger devices and highlight significant changes in the water table. After 13 months of data recording (May 2018), rock samples were removed, reweighted and the volume loss measured. In addition, water from piezometer-experiment, representative of the groundwater circulation, were collected at different depths. The obtained results indicate that rock sample reduction is dependent on the hydrological regime and water chemistry and not on the number of days during which the samples remained submersed. In particular, the water geochemistry highlights the possible role in gypsum/anhydrite dissolution due to NaCl water admixing in a complex scenario. In additional, the geochemical data highlight the occurrence of some potentially toxic elements (As, Fe, Mn) at concentrations of concern in some water. This approach represents a novel contribution in the study of karst hazard in evaporites adding a tile to the knowledge of the fast evolutionary processes which cause sinkhole formation.
- Published
- 2019
- Full Text
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39. Origin of Reverse Zoned Cr-Spinels from the Paleoproterozoic Yanmenguan Mafic–Ultramafic Complex in the North China Craton
- Author
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Yang Bai, Ben-Xun Su, Yan Xiao, Davide Lenaz, Patrick Asamoah Sakyi, Zi Liang, Chen Chen, and Sai-Hong Yang
- Subjects
compositional zoning ,spinel ,elemental exchange ,North China Craton ,Mineralogy ,QE351-399.2 - Abstract
We conducted petrological and mineral chemistry investigations of Cr-spinel in ultramafic rocks of the Yanmenguan mafic–ultramafic complex in the North China Craton. The Cr-spinel grains occur as inclusions in enstatite, tschermakite, phlogopite, and olivine, or as interstitial grains among the aforementioned silicate minerals, and show concentric or asymmetrical textures. Back-scattered electron and elemental images and compositional profiles of the spinel grains indicate the presence of Cr- and Fe-rich cores and Al- and Mg-rich rims. The host silicate minerals display a decrease in Al and Mg contents accompanied by an increase in Cr and Fe away from the spinel. These textures and compositional variations suggest that subsolidus elemental exchange more likely gave rise to the compositional zonation, resulting in the transfer of Al and Mg from the silicate minerals to the spinel. The Mn, Ni, and Ti contents in spinel and the major elements of olivine-hosted spinel are relatively stable during subsolidus elemental diffusion and thus are more reliable tracers of primary high-temperature processes. The temperature estimates reveal that the subsolidus diffusion might have occurred at 600–720 °C, which could be linked to the regional metamorphic event.
- Published
- 2018
- Full Text
- View/download PDF
40. Following the Amphibolite to Greenschist Metamorphic Path through the Structural Parameters of Spinels from Amsaga (Mauritania)
- Author
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Davide Lenaz, Henrik Skogby, Nicola Rigonat, and Julien Berger
- Subjects
Cr-bearing spinel ,chemistry ,X-ray single crystal diffraction ,Mössbauer spectroscopy ,Archean ,Mauritania ,Mineralogy ,QE351-399.2 - Abstract
We investigated the crystal and structural behavior of several Cr-bearing spinels from the Archean chromitites of Amsaga (Mauritania). The chemical and structural data testified a retrograde metamorphism from amphibolite to greenschist facies, witnessed by relative changes in the amount of all the major oxides (Cr, Al, Mg, Fe2+, Fe3+), the relative proportion of Fe3+/Fetot as well as the structural parameters, including the cell edge and the oxygen coordinate. The general agreement between electron microprobe and Mössbauer data indicates that the analyzed spinels are stoichiometric. The structural data revealed that the oxygen positional parameter of amphibole-bearing samples is the highest observed among Cr-bearing spinels with similar Cr# and Mg#. Consequently, it is suggested that a structural study of detrital Cr-spinels could be important in discriminating an amphibole-chromitite source from an ophiolite source.
- Published
- 2018
- Full Text
- View/download PDF
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