135 research outputs found
Trasferimento locale di energia in fluidi geofisici e plasmi spaziali
No full textTurbulence in geophysical fluids and space plasmas compete with internal waves in transferring the energy across scales. Evidences point to the possibility that an upscale energy transfer, resembling the case of two-dimensional turbulent flows, may develop in the atmosphere and in the oceans, under the effect of rotation, perhaps helped by the large aspect ratio of the domain. Indeed, bi-directional energy transfers (to large and small scales) have been observed in different natural contexts, in the oceans, for instance, but also in kinetic plasmas, in which magnetic fields support the propagation of waves, and magnetic reconnection contributes to make the dynamics of these flows even richer. In these frameworks, characterized by strong inhomogeneity and anisotropy, standard analysis tools can only provide partial information on how energy is distributed over the various scales. In order to achieve a more exhaustive characterization of the energy transfer, in this thesis we employed the so-called space-filtering (SF) technique to investigate the energetics of stratified turbulent flows of geophysical interest, and of plasmas in the kinetic regime, the latter being relevant to understand the dynamics of the interplanetary medium. In particular, we targeted two major phenomena, the extreme vertical drafts developing in the stratified geophysical flows, and the reconnection events observed in heliospheric and magnetospheric plasmas, always using simulation data.
After further refining the SF technique, we used it to analyze a set of direct numerical simulations of stratified flows, varying the Froude number, focusing on the feedback of developing extreme vertical drafts on the energy transfer, locally in the physical and the Fourier space. We were able to verify that vertical drafts do actually inject energy, ultimately enhancing turbulence and dissipation, affecting the mixing properties of geophysical flows. The same approach was finally implemented on the outputs of hybrid-kinetic plasma simulations to asses the effects of magnetic reconnection events on the energy transfer at the sub-ion scales. Our analysis emphasized for the first time the role of reconnection as a trigger for dual energy transfers, simultaneously towards scales larger and smaller than the scales associated to the observed reconnection events
Characterization of local energy transfer in large-scale intermittent stratified geophysical flows via space filtering
No full textRecent studies based on simulations of the Boussinesq equations indicate that
stratified turbulent flows can develop large-scale intermittency in the
velocity and temperature fields, as detected in the atmosphere and in the
oceans. In particular, emerging powerful vertical drafts were found to generate
local turbulence, proving necessary for stratified flows to dissipate the
energy as efficiently as homogeneous isotropic turbulent flows. The existence
of regions characterized by enhanced turbulence and dissipation, as observed,
for instance, in the ocean, requires appropriate tools to assess how energy is
transferred across the scales and at the same time locally in the physical
space. After refining a classical space-filtering procedure, here we
investigate the feedback of extreme vertical velocity drafts on energy transfer
and exchanges in subdomains of simulations of stably stratified flows of
geophysical interest. Our analysis shows that vertical drafts are indeed able
to trigger upscale and downscale energy transfers, strengthening the coupling
between kinetic and potential energies at certain scales, depending on the
intensity of the local vertical velocity
Raffaello Pantucci
No full textRaffaello Pantucci est actuellement directeur des Etudes de Sécurité Internationale au RUSI (Royal United Services Institute). Ses recherches portent sur le contre-terrorisme et les relations de la Chine avec ses voisins occidentaux. Raffaello Pantucci is currently the director of International Security Studies at RUSI (Royal United Services Institute). His research focuses on counter-terrorism as well as China’s relations with its Western neighbours. He is the author of «We Love Death As Yo..
Automatic detection of field line resonance frequencies in the Earth’s plasmasphere
No full textGround-based magnetometer stations represent a multi-viewpoint and easy-to-access system for sounding Earth's magnetic field disturbances in the inner magnetosphere. Using Ultra-Low Frequency (ULF) measurements recorded from pairs of meridionally aligned stations, it is possible to determine the Field Line Resonance (FLR) frequencies, which are directly related to the equatorial magnetospheric plasma mass density. Recently, it has been shown by Foldes et al. (J Geophys Res 126(5):e2020JA029008. https://doi.org/10.1029/2020JA029008, 2021) that the Machine Learning (ML) algorithms are valuable tools for detecting FLRs by exploiting the useful information provided by cross-phase Fourier spectra, which are at the heart of the ULF technique for inferring the magnetospheric mass density. The main shortcoming of this approach is that it is not possible to discriminate between active and quiet times in terms of resonances. It is commonly known that detecting FLRs using cross-phase spectra may often be unfeasible due to data gaps, noisy signals, and/or quiescent ULF wave periods. To handle these situations, we implement an ML classification algorithm to identify periods when the resonance frequencies are observable and thus easily estimated. Our algorithm can distinguish samples into three main classes: periods with observed frequency ("Freq" class) from others ("NoFreq"), and, in addition, it can determine whether the considered field line crosses the plasmasphere boundary layer (PBL or plasmapause) at a given time. The results of our method are validated for a particular pair of stations (at L = 2.9) along the Equatorial quasi-Meridional Magnetometer Array (EMMA), using a large dataset comprising different geomagnetic conditions. The proposed approach might be combined with a regression algorithm (such as those proposed in Foldes et al. (J Geophys Res 126(5):e2020JA029008. https:// doi.org/10.1029/2020JA0290 08, 2021)) in a two-stage ML pipeline, with the ultimate goal of implementing a completely automated system for the real-time monitoring of the plasmasphere dynamics from ground-based magnetometer stations
Spartaco al tempo dell’Unità d’Italia. Sul romanzo di Raffaello Giovagnoli
No full textIl saggio riguarda il romanzo "Spartaco" di Raffaello Giovagnoli (Roma 1873, 18752 ecc.), qui analizzato come caso signficativo di ricezione dell'antichità romana nella cultura italiana degli anni immediatamente successivi all'Unità d'Italia.This paper focuses on the novel "Spartaco" by Raffaello Giovagnoli (Rome 1873, 18752 etc.) as a significant example of the reception of Roman antiquity in the years following Italian Unity. The author addresses issues related to the content and circulation of the novel and to its ideological stance
Modernamente antica: la tomba di Raffaello al Pantheon
No full textGiorgio Vasari riferisce le disposizioni testamentarie di Raffaello per la sepoltura in un’antica edicola all’interno della chiesa della Rotonda, Santa Maria ad Martyres, il Pantheon. Nonostante l’importanza del monumento, sono sconosciuti il progetto originario e la sua realizzazione, successivamente mutata più volte sino all’assetto odierno delineato nel 1933 per la Soprintendenza ai monumenti da Alberto Terenzio.
Ripercorrendo le motivazioni della scelta del Pantheon da parte dell’artista urbinate e collegandole a quanto noto dell’edificio in generale e dell’edicola in particolare, prima e dopo la morte di Sanzio, l’autrice ricostruisce la conformazione della tomba e dell’altare con la Madonna del Sasso scolpita da Lorenzetto nel suo sviluppo diacronico, oscillante tra conservazione e trasformazione.Giorgio Vasari refers to Raphael's testamentary dispositions for burial in an ancient aedicule inside the church of the Rotonda, Santa Maria ad Martyres, the Pantheon. Despite the importance of the monument, the original project and its realisation are unknown, and it was subsequently modified several times until the present layout was outlined in 1933 by Alberto Terenzio for the Monuments Office.
Tracing the reasons for the artist's choice of the Pantheon in Urbino and linking them to what is known about the building in general and the aedicula in particular, before and after Sanzio's death, the author reconstructs the conformation of the tomb and the altar with the Madonna del Sasso sculpted by Lorenzetto in its diachronic development, oscillating between conservation and transformation
LA MADONNA ESTERHAZY DI RAFFAELLO
No full textLA MADONNA ESTERHÁZY DI RAFFAELLO A PALAZZO MARINO, di Francesco Murano,
Fotografie di Sergio Oriani
Il curatore della mostra, Stefano Zuffi, ha voluto inquadrare criticamente l’opera di Raffaello
proveniente dal Museo di Budapest, ponendola tra la Vergine delle Rocce di Francesco Melzi,
proveniente dall’Istituto delle Suore Orsoline di Milano e la Madonna della Rosa di Giovanni
Antonio Boltraffio, proveniente dal Museo Poldi Pezzoli della stessa città. L’architetto Corrado
Anselmi ha progettato un affascinante allestimento, concependolo come un percorso che si
sviluppa attraverso tre soste utili all’ammirazione delle opere. L’autore Francesco Murano,
spiega con ricchezza di particolari i vincoli del progetto illuminotecnico e le scelte luministiche.Once again, for the Christmas season, the Municipally of Milan decided to display an important work in the frame of the Palazzo Marino’s Alessi Hall. For this year 2014, the choice has been to propose the Estheràzy Madonna by Raphael, from the Museum of Budapest.
The exhibition curator, Stefano Zuffi, wanted to critically frame to work of Raphael by placing it between the Vegine delle Rocce (Virgin of the Rocks) by Francesco Melzi, coming from the Milan’s Istituto delle Suore Orsoline, and the Madonna della Rosa by Giovanni Boltraffio, from the Milanese Museo Poldi Pezzoli.
The Architect Corrado Anselmi designed a fascinating display, convinced as a path that develops through three stops that are useful for the enjoyment of the works.
The author Francesco Murano, explains with many details the lighting design project
Choice, workplace flexibility and care needs in the digital age: a comparison between the German and Italian legal approaches
No full textThe aim of this paper is twofold: to highlight the potential and limitations of the new right to request flexible working arrangements for caring purposes, as established in Directive no. 2019/1158, and to consider, through an overview of EU law, whether and to what extent this right can be interpreted in a manner that truly favours the interests of workers with care-related responsibilities over those of employers.
The paper analyses some examples of approaches taken regarding the implementation of the right to request flexible working arrangements in two different jurisdictions, such as Germany and Italy and compares the transposing choices made in the two different legal contexts. The author argues, also in light of this investigation, that the potential of the duty to provide flexible working arrangements could be, to a certain extent, enhanced through the application of the prohibition of indirect discrimination, from which a sort of duty of accommodation could be inferred. The duty to provide flexible working arrangements could constitute the procedural tool to apply and enhance the proportionality test and reasonable accommodation
Telelavoro e mobile Arbeit in Germania: sfide e opportunità
No full textIl saggio parte da una ricognizione delle fonti di disciplina del lavoro a distanza
nel sistema tedesco, dando conto del dibattito sviluppatosi in questa materia, anche in
una prospettiva de iure condendo, sugli aspetti più problematici, come quelli inerenti
alle questioni definitorie, alla qualificazione del rapporto di lavoro, alla volontarietà,
all’organizzazione dell’orario di lavoro, ai rischi per la salute e la sicurezza, al potere
di controllo e la tutela della privacy e infine alla fornitura delle attrezzature di lavoro.
Nella parte finale l’a. conclude, tra l’altro, che in Germania la questione della natura
subordinata del rapporto con riguardo alle forme organizzative in esame può essere in
qualche misura sdrammatizzata, sebbene sia ancora attuale come in Italia. Infine, auspica
la sperimentazione di tecniche in grado di garantire un equilibrato dosaggio tra fonti
eteronome ed autonome, come è il caso delle classiche clausole di apertura menzionate
nelle proposte tedesche più recenti.
The essay starts with an analysis of the legal framework and the collective bargaining on remote work in Germany, providing an account of the literature on the
most problematic aspects, such as those related to employee status issues, the voluntary
nature of the introduction of mobile work, the working time, health and safety risks,
monitoring, surveillance and data protection and, finally, work equipment. In the final
section the a. concludes that the question of the classification of mobile worker as
employee cannot be understimated neither in Germany nor in Italy. The Author
draws inspiration from the German case for proposing, in the last part of the paper,
the adoption of the techniques, traditionally used in Germany, capable of guaranteeing
a balanced mix between heteronomous and autonomous sources, as is the case with
the opening clauses mentioned in the most recent German draft legislation
The Onano Pyroclastic Formation (Vulsini volcanoes): depositional features, distribution and eruptive mechanisms
No full textField relations, areal distribution and depositional sequence of the units which constitute the Onano Pyroclastic Formation (ON) are analyzed and discussed in detail. The eruptive events linked to the emission of the ON products take place during the initial stages of the last Latera calderic collapse. -from Author
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