6,180 research outputs found

    Three-dimensional reconstruction of CME-driven shock-streamer interaction from radio and EUV observations: a different take on the diagnostics of coronal magnetic fields

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    On 2014 October 30, a band-splitted type II radio burst associated with a coronal mass ejection (CME) observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO) occurred over the southeast limb of the Sun. The fast expansion in all directions of the plasma front acted as a piston and drove a spherical fast shock ahead of it, whose outward progression was traced by simultaneous images obtained with the Nan\c{c}ay Radioheliograph (NRH). The geometry of the CME/shock event was recovered through 3D modeling, given the absence of concomitant stereoscopic observations, and assuming that the band-splitted type II burst was emitted at the intersection of the shock surface with two adjacent low-Alfven speed coronal streamers. From the derived spatiotemporal evolution of the standoff distance between shock and CME leading edge, we were finally able to infer the magnetic field strength BB in the inner corona. A simple radial profile of the form B(r)=(12.6±2.5)r−4B(r) = (12.6 \pm 2.5) r^{-4} nicely fits our results, together with previous estimates, in the range r=1.1−2.0r = 1.1-2.0 solar radii.Comment: Accepted for publication in Astronomy & Astrophysics Letter

    Gabriella D\u2019AGOSTINO \u23b8Sottotraccia: Percorsi tra antropologia e contemporaneit\ue0, Acireale-Roma, Bonanno, 2016

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    Book review of Gabriella D’Agostino, Sottotraccia. Percorsi tra antropologia e contemporaneità, Acireale-Roma, Bonanno, 2016, pp.163.Recensione di Gabriella D’Agostino, Sottotraccia. Percorsi tra antropologia e contemporaneità, Acireale-Roma, Bonanno, 2016, pp.163

    Incertezza, precariet\ue0, capacit\ue0 di immaginazione del futuro e modernit\ue0: un confronto tra Appadurai e De Martino

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    Though apparently distanced for their temporal and historical moment, their conceptual terminology, their interlocutors and the fields of their empirical research, it is possible to get some notable parallelisms of theoretical vision between the anthropological work of De Martino and that of Appadurai. In both cases, their starting point is in fact the uncertainty of human condition and social orders, and at the heart of their theory, there stands the issue of identifying the different kinds of ethos and cultural activity which permit people to historically and existentially confront this uncertainty through establishing their belonging to a \u201ccultural homeland\u201d (De Martino) or forms of social imagination which shape the capacities of constructively projecting themselves into the future (Appadurai). In this article, I trace a comparison among different components of both anthropologists\u2019 theoretical apparatus, trying not only to sketch the basic elements of their \u201cgeneral anthropology\u201d, but also their interplay with their interpretation of causes, phenomenology and possible ways out of the contemporary crisis, of cognitive and ethical kind, in the capacity for imagining the future in today globalised world. In their diagnosis of the present, De Martino and Appadurai, though sharing the idea that reference to universalistic values inherited by European modernity does not provide more an adequate frame for interpretation, express divergent views about modernity, its European matrix and the ethical dispositions which grow with it

    Postfazione: L\u2019antropologia, il non umano e l\u2019ontological turn

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    This afterword has two aims: a short critical assessment of the so-called \u201contological turn\u201d in the human sciences, and a critical commentary on some of the issues raised by the articles gathered in this special issue on the anthropology of the non-human. I argue that, as underlined by all the contributors, the question of how we think about the nature of politics and power relations is crucial for any evaluation of this new \u201cturn\u201d. An examination of the treatment given by Descola, Latour, Viveiros de Castro and their followers to the issue of power must account for the differences among these theoretical approaches and the political implications that can be draw from each of them. However, on the whole \u201contological\u201d approaches seem to miss the complexity of factors that mediate between the ontological and the political. All the articles of this special issue deal with this issue, though ethnographic case studies concerning diverse fields of research have rarely explored till now an explicitly \u201conto-political\u201d perspective. Furthermore, the articles cover a range of issues broader than those of \u201contological\u201d interest, and so contribute to linking current discussions of the \u201contological turn\u201d with other areas of the contemporary anthropological debate

    La parziale incidenza del nuovo sistema di diritto internazionale privato nella materia concordataria

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    LA PARZIALE INCIDENZA DEL NUOVO SISTEMA DI DIRITTO INTERNAZIONALE PRIVATO NELLA MATERIA CONCORDATARIA ABSTRACT La legge 31.05.1995, n. 218, ha riformato la normativa vigente per il riconoscimento delle sentenze straniere introducendo una forma automatica di riconoscimento che per vari motivi non \ue8 applicabile alle sentenze canoniche di nullit\ue0 del matrimonio, e, conseguentemente, ha abrogato gli artt. 796 e 797 c.p.c. sostituendoli con gli artt. 64 e 67 che disciplinano le ipotesi residue in cui si renda necessario procedere egualmente alla delibazione. Gli articoli contenuti nel codice di procedura civile sono comunque rimasti in vigore nel procedimento volto a dare efficacia civile alle sentenze dei tribunali ecclesiastici in quanto espressamente richiamati dal n. 4 del Protocollo addizionale dell\u2019Accordo di modificazione del Concordato lateranense stipulato tra Stato e Chiesa nel 1984, reso esecutivo con l. 25.03.1985, n.121. Il lavoro vuole, pertanto, approfondire quest\u2019ultimo aspetto, analizzando le differenze tra la vecchia e la nuova normativa in riferimento alle condizioni per la delibazione indicate dagli artt. 64 e 67 della l. 218/95 che vengono comparate a quelle degli artt. 796 e 797 c.p.c., per vedere se \ue8 possibile una parziale applicazione della nuova legge nei confronti delle sentenze canoniche senza che venga alterato in modo sostanziale il sistema pattizio di ricezione delle sentenze ecclesiastiche nell\u2019ordinamento italiano. L\u2019esame delle citate disposizioni porta a concludere a favore di questa tesi e se ne argomentano i motiv

    A genetic algorithm for combined topology and shape optimisations

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    A method to find optimal topology and shape of structures is presented. With the first the optimal distribution of an assigned mass is found using an approach based on homogenisation theory, that seeks in which elements of a meshed domain it is present mass; with the second the discontinuous boundaries are smoothed. The problem of the optimal topology search has an ON/OFF nature and has suggested the employment of genetic algorithms. Thus in this paper a genetic algorithm has been developed, which uses as design variables, in the topology optimisation, the relative densities (with respect to effective material density) 0 or 1 of each element of the structure and, in the shape one, the coordinates of the keypoints of changeable boundaries constituted by curves. In both the steps the aim is that to find the variable sets producing the maximum stiffness of the structure, respecting an upper limit on the employed mass. The structural evaluations are carried out with a FEM commercial code, linked to the algorithm. Some applications have been performed and results compared with solutions reported in literature. \uc2\ua9 2003 Elsevier Science Ltd. All rights reserved

    Lay-up optimization for the hull of a racing sailing yacht

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    Deformability and buckling load of yacht hulls with fiber reinforced plastic sandwich structure depend on the stack sequence of the skins. In this work an optimization of fiber directions of the laminae for a racing yacht is proposed. This procedure has been divided into three parts (i.e. material characterization, surface model definition, lay-up optimization). First of all a set of unidirectional specimens has been realized, by using the same fibers and matrix (carbon/epoxy) used for the hull as well as the same procedure and workers, in order to characterize the material according to American Society for Testing and Materials (ASTM) Standard D3039, employing strain gage technique. In the second part, by means of an original software in Turbo-Pascal (which uses the half-width value matrix as an input) linked to Pro/ENGINEER, it has been possible to obtain the body plan and surface and finite element (FE) models of the sailing yacht for the subsequent analyses. In the third step, an optimization procedure that uses the results of FE structural analyses in three different sailing configurations is performed, with the aim of obtaining the fiber directions that are able to minimize the yacht deformability, also taking into account the buckling loads. An approximate analytical model has been used in conjunction with a sweep technique in order to evaluate the best of the solutions

    Advanced Techniques for Design and Manufacturing in Marine Engineering

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    Modern engineering design processes are driven by the extensive use of numerical simulations, and naval architecture as well as ocean engineering are no exception. Structural design or fluid dynamic performance evaluation can only be carried out by means of several dedicated pieces of software. Classical naval design methodology can take advantage of the integration of these pieces of software, giving rise to more robust design in terms of shape, structural and hydrodynamic performances, and manufacturing processes. This Special Issue (SI) on “Advanced Techniques for Design and Manufacturing in Marine Engineering”, published in the Journal of Marine Science and Engineering, aimed to invite researchers and engineers from both academia and industry to publish the latest progress in design and manufacturing techniques in marine engineering as well as to debate current issues and future perspectives in this research area. After a rigorous peer review process we accepted 11 papers [1–11], covering a wide range of topics related to the themes proposed in the Special Issue. In [1], machine-learningbased algorithms are developed in order to enhance the real-time decision process of an AUV sailing yacht. In [2], topology optimization techniques and laser powder bed fusion manufacturing have been synergically adopted to redesign the bulb of sailing yachts, leading to drag reduction and improving overall boat performance. In [3], the topic of sail design is discussed by means of numerical fluid structure interaction methods and a practical tool is proposed to support the analyst during the design process of a yacht sail plan. The sail design process is also investigated in [4] but using different tools, such as combining a velocity prediction program, RANS computations, and analytical approaches. The problem of grid generation in a CFD model has been studied in [5], where the authors propose, for the particular shape of a submarine, an automated procedure based on Cartesian adaptive grids. The applicability of a CFD numerical technique to a complex biphase fluid medium is the key point of [6], where the robustness of the method is tested to simulate the ventilation phenomenon occurring in stepped hull planing motor yachts. In [7], an analytical tool incorporating the main dimensional naval coefficients of a sailing boat is adopted during the early design stage, with the additional aim of quickly predicting the overall resistance of the hull. In [8], different pieces of sensor information have been used by the authors to train an algorithm able to control water sample collection in deep water. Computational methods have been used in [9] to determine the resistance of ship fuel tanks when subjected to an increased internal pressure. In [10], a simulation model has been used to design a platform able to compensate for the wave action on a vessel, with particular attention to the shape optimization of the structure in order to reduce the total weight. Finally, in [11], CFD tools using moving meshes have been adopted to simulate turbulent flows that originate in an oscillating water column device and move a Savonius turbine

    Virtual prototyping of a new intramedullary nail for tibial fractures

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    In this work a new distal interlocking system has been developed which is easy to use, allows a reduction of the operating time and consequently the exposure to radiations both for surgeon and patient. The main goal of this study has been the design of a new intramedullary nail for tibial fractures able to simplify and speed up the distal locking operation phases. After a preliminary stage during which several candidate concepts have been proposed and analysed, the best solution has been developed and deeply investigated. The new system, called "expansion nail", has been firstly modelled by setting up a full parametric CAD model and, then, tested by running non linear FEM analyses to evaluate stresses and stability of the joining during normal working conditions. The new design has shown very high mechanical stability in the axial compression and torsional load cases. Since its very simple self-locking system, the new expansion intramedullary nail would reduce the operating time and the exposure to radiations for the surgeons as well as the patients
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