Seismic Vulnerability of the Italian Roadway Bridge Stock

This study focuses on the seismic vulnerability evaluation of the Italian roadway bridge stock, within the framework of a Civil Protection sponsored project. A comprehensive database of existing bridges (17,000 bridges with different level of knowledge) was implemented. At the core of the study stands a procedure for automatically carrying out state-of-the-art analytical evaluation of fragility curves for two performance levels – damage and collapse – on an individual bridge basis. A webGIS was developed to handle data and results. The main outputs are maps of bridge seismic risk (from the fragilities and the hazard maps) at the national level and real-time scenario damage-probability maps (from the fragilities and the scenario shake maps). In the latter case the webGIS also performs network analysis to identify routes to be followed by rescue teams. Consistency of the fragility derivation over the entire bridge stock is regarded as a major advantage of the adopted approach

Improved Lindstedt-Poincare method for the solution of nonlinear problems

We apply the Linear Delta Expansion (LDE) to the Lindstedt-Poincare (``distorted time'') method to find improved approximate solutions to nonlinear problems. We find that our method works very well for a wide range of parameters in the case of the anharmonic oscillator (Duffing equation) and of the non-linear pendulum. The approximate solutions found with this method are better behaved and converge more rapidly to the exact ones than in the simple Lindstedt-Poincar\'e method.Comment: 24 pages, 7 figures, RevTex

Presenting a new method for the solution of nonlinear problems

We present a method for the resolution of (oscillatory) nonlinear problems. It is based on the application of the Linear Delta Expansion to the Lindstedt-Poincar\'e method. By applying it to the Duffing equation, we show that our method substantially improves the approximation given by the simple Lindstedt-Poincar\'e method.Comment: 12 pages, 3 figures. LATE

The Distributional Stress-Energy Quadrupole

We investigate stress-energy tensors constructed from the delta function on a worldline. We concentrate on the quadrupole which has up to two partial or derivatives of the delta function. Unlike the dipole, we show that the quadrupole has 20 free components which are not determined by the properties of the stress-energy tensor. These need to be derived from an underlying model and we give an example modelling a divergent-free dust. We show that the components corresponding to the partial derivatives representation of the quadrupole, have a gauge like freedom. We give the change of coordinate formula which involves a second derivative and two integrals. We also show how to define the quadrupole without reference to a coordinate systems or a metric. For the representation using covariant derivatives, we show how to split a quadrupole into a pure monopole, pure dipole and pure quadrupole in a coordinate free way

Recovery and Maintenance Scenarios for the Productive Landascape

The research experience performed by the Reuse, Recovery and Maintenance Laboratory (LRRM) of DiARC refers to PRIN project “The defence of the landscape between conservation and transformation. Economics and beauty for sustainable development”. The researchhas addressed the issue of the rebalancing of the relationship between physical space, established communities, economies. The productive urban landscape of Torre Annunziata, identified as a case study, has been analyzed as a complex and adaptive system. It is the result of processes that have determined, in time, the identity of the territories. The paper illustrates the methodology for interpretation of built environment. The work is aimed to identify the conservative and transformative vocations, to draw project scenarios compatible with Raccomandation of Historic Urban Landscape Unesco, 2011

Geometrical Interpretation of Multipoles and Moments on Differential Manifolds

In this thesis, the construction of a specific family of linear functionals with support on a closed embedding c : R ,→ M upon a manifold is discussed. The construction is performed in a purely coordinate free fashion, based on the De Rham push-forward approach and generalised to define "tensorial currents" called "multipoles". Several geometrical and algebraic properties are investigated and two main useful classes of non-trivial coordinate representations are compared and related to the choices of some extra structures on the manifold (i.e. affine connection, foliation, adapted atlas, adapted frames). It is shown that in general, the transformation rules are not given by the action of the linear group, unless some information upon the "transverse" directions with respect to the closed embedding is provided. It is shown how the multipoles are the geometrical objects naturally arising when some specific one parameter families of compact support tensor fields are expanded asymptotically around the closed embedding. In case a one parameter family satisfies also an extra condition (i.e. self similarity) it is shown how to recover the well known standard definition of "moments", opening the door to a new completely covariant and coordinate free meaning of the concept of "multipole expansion" of functions and tensor field upon the differential manifolds. It is shown how these linear functionals admit a coordinates representation coinciding with the moments commonly defined to perform the Pole-Dipole approximation of an Energy-Momentum Tensor field in General Relativity, and when a Levi Civita connection is assumed on a pseudo-Riemmanian manifold, the first two multipoles related to an Energy Momentum tensor field expansion can easily satisfy the well known Mathisson-Papapetrou-Dixon equation. Since the proposed method of construction of the multipoles does not rely on a specific metric or a specific affine connection, a generalisation of the Pole-Dipole approximation for a non metric connection is easily achieved, casting the Mathisson-Papapetrou-Dixon equation in presence of a non null torsion. Because of this, there is hence the possibility to interpret the test particles and test charges within the Relativistic Theories (possibly beyond General Relativity) just as the multipole approximation of the regular sources of the interaction fields, with a new clear geometrical background

Tra salute e ambiente: osservazioni sul ruolo del Diritto di fronte alla crisi

Abstract (en): The necessity of a greater international collaboration has grown in importance in light of the recent epidemic caused by the new coronavirus. The current emergency is not only a major public health problem, but it represents a social, economical and psychological concern as well. Moreover, while the world is fighting a global health crisis, another issue that could lead to even more serious consequences requires sustained effort and immediate attention: the climate crisis. It is relevant to highlight that health and the ecosystem are not to be viewed as separated issues. Indeed, their correlation has important implications for the legal systems since an awareness on the necessity to handle the climatic crisis also in a public health perspective/dimension is to be encouraged. In this perspective, the United Nations’ 2030 Agenda serves as a useful instrument. An holistic approach is to be required to achieve a type of sustainability that includes economic, social, environmental and institutional factors and is to be adopted as the only possible way to be prepared for facing the future environmental and health challenge

Modulation of pure spin currents with a ferromagnetic insulator

We propose and demonstrate spin manipulation by magnetically controlled modulation of pure spin currents in cobalt/copper lateral spin valves, fabricated on top of the magnetic insulator Y$_3$Fe$_5$O$_{12}$ (YIG). The direction of the YIG magnetization can be controlled by a small magnetic field. We observe a clear modulation of the non-local resistance as a function of the orientation of the YIG magnetization with respect to the polarization of the spin current. Such a modulation can only be explained by assuming a finite spin-mixing conductance at the Cu/YIG interface, as it follows from the solution of the spin-diffusion equation. These results open a new path towards the development of spin logics.Comment: 5 pages and 4 figures + supplemental material (10 pages, 7 figures

X-ray variability with WFXT: AGNs, transients and more

The Wide Field X-ray Telescope (WFXT) is a proposed mission with a high survey speed, due to the combination of large field of view (FOV) and effective area, i.e. grasp, and sharp PSF across the whole FOV. These characteristics make it suitable to detect a large number of variable and transient X-ray sources during its operating lifetime. Here we present estimates of the WFXT capabilities in the time domain, allowing to study the variability of thousand of AGNs with significant detail, as well as to constrain the rates and properties of hundreds of distant, faint and/or rare objects such as X-ray Flashes/faint GRBs, Tidal Disruption Events, ULXs, Type-I bursts etc. The planned WFXT extragalactic surveys will thus allow to trace variable and transient X-ray populations over large cosmological volumes.Comment: Proceedings of "The Wide Field X-ray Telescope Workshop", held in Bologna, Italy, Nov. 25-26 2009 (arXiv:1010.5889). To appear in Memorie della Societ\`a Astronomica Italiana 2010 - Minor corrections to text