INTERFACE MODEL FOR THE NONLINEAR ANALYSIS OF BLOCKY STRUCTURES OF ANCIENT GREEK TEMPLES

The presence of singularity surfaces with reference to the displacement field is a characteristic of a number of structural systems. Strong discontinuities are present in old masonry structures where dry joints connect the blocks or the mortar ageing suggests to neglect the adhesion properties. These structures cannot be considered a continuum but rather an assembly of blocks. These discontinuous structures could be modelled as an assembly of blocks interacting trough frictional joints whose mechanical behaviour is described by appropriate interface laws. In the present work an interface model present in literature is adopted, the double asperity model, which has been implemented in a standard finite element code with the principal aim to develop structural analysis of old monumental masonry structures. The interface model is briefly illustrated and the numerical implementation of the interface laws is described in detail. Numerical examples are presented to simulate the behaviour of a couple of greek temples of Agrigento Italy. These old monumental structures, IV-VI sec. BC, are inserted in the world heritage list by Unesco

Testing for Asymmetries and Anisotropies in Regional Economic Models

This paper develops a new methodology for estimating and testing the form of anisotropy of homogeneous spatial processes. We derive a generalised version of the isotropy test proposed by Arbia, Bee and Espa (2013) and analyse its properties in various settings. In light of this, we propose a new approach that allows one to estimate and test under mild conditions any form of anisotropy in homogeneous spatial processes. The power of the test is studied by means of Monte Carlo simulations performed both on regularly and irregularly spaced data. Finally, the method is used to analyse the soybeans yields in the US

Revealing radiationless sources with multi-harmonic mantle cloaking

A general formula for the scattering suppression of simultaneous cylindrical harmonic waves is reported for a bare dielectric cylinder. A proper surface impedance condition is imposed at the boundary between dielectric and background regions, revealing a parity-time condition for the internal electromagnetic field in order to be nonradiating. Depending on the maximum number M_max of cylindrical harmonic waves to suppress along the azimuthal variable phi, such surface impedance function profile reveals several higher order nonradiating modes. The determination of M_max is consistent with the degrees of freedom of the scattered fields. Moreover, the multi-harmonic mantle cloaking technique automatically generates radiationless sources suitable for the implementation with metal-dielectric metasurfaces or all-dielectric metamolecules

A Cross-Entropy Approach to the Estimation of Generalised Linear Multilevel Models

In this paper we use the cross-entropy method for noisy optimisation for fitting generalised linear multilevel models through maximum likelihood. We propose specifications of the instrumental distributions for positive and bounded parameters that improve the computational performance. We also introduce a new stopping criterion, which has the advantage of being problem-independent. In a second step we find, by means of extensive Monte Carlo experiments, the most suitable values of the input parameters of the algorithm. Finally, we compare the method to benchmark estimation technique based on numerical integration. The cross-entropy approach turns out to be preferable from both the statistical and the computational point of view. In the last part of the paper, the method is used to model death probability of firms in the healthcare industry in Italy

Pennsylvanian floras from Italy: an overview of the main sites and historical collections

The paper provides an overview of the main Pennsylvanian sites in Italy yielding associations rich in plants and/or palynomorphs. So far in Italy, the principal outcrops are located in the Southern Alps, Tuscany and Sardinia. In the Western Southern Alps and bordering Switzerland, Westphalian outcrops are small and scattered. Nevertheless they yielded an abundant fossil flora, stored at the Museo Civico di Storia Naturale of Milan-, (Venzo and Maglia Collection). In the Carnic Alps-, (Eastern Southern Alps)-, continental deposits of Moscovian to Gzhelian age also occur near the border with Austria. They have produced a high number of preserved plant fossils, presently stored in the Museo Friulano di Storia Naturale of Udine. In Tuscany, the two main sections yielding Westphalian to Autunian floras are those of the Iano and Pisani Mountains. A rich collection of plant fossils from those sites is hosted at the Museo di Storia Naturale of Florence University and at the Museum of Natural History of Pisa University. In Sardinia, plant fossil sites are located in the south west and central east parts of the island. The San Giorgio Basin (Iglesiente subregion) and the Tuppa Niedda section (Arburese subregion) are late Westphalian – early Stephanian in age. In the Barbagia at Seui-Seulo and the Gerrei subregions, other continental basins yielded transitional “Stephanian- Autunian” fossil plant associations. The slabs are stored as part of the Lovisato Collection at the Lovisato Museum of the Chemical and Geoscience Department of Cagliari University. Smaller historical outcrops of Carboniferous age are also known from other Italian regions, such as Liguria.</p