[en] The aim of the present work was to achieve by ion-mixing the formation of amorphous alloys and to investigate the role of the sample temperature during the ion-implantation with respect to the amorphization degree of the resulting films. (Auth.)

[en] The direct deposition of silicon carbide by pyrolysis of methyltrichlorosilane in Ar-H₂ atmosphere onto WC-Co based cermet substrates causes the formation of cobalt silicides, the secondary η-phase, and consequent adhesion failure. To minimize this adhesion failure, layers based on TiN, Ti(C,N) were deposited. Investigations of the chemical composition of chemically vapour deposited multilayers and interfaces were performed using scanning electron microscopy, X-ray diffraction and Auger spectroscopy techniques, the adhesion was evaluated using the scratch test. Promising mechanical properties (adhesion and hardness) of the chemically vapour deposited SiC were obtained using these intermediate multilayers. The average stress was also calculated as a suitable adhesion parameter. The relationship between the interface composition and the quality of adhesion is also discussed. (orig.)

[en] In this paper we report some results on the design of a grid computing application in the field of environmental sciences. The case study concerns the integration of several independent computational models (weather, air and water quality and sea wave and currents) aver a grid computing infrastructure. The aim of the project is the development of an efficient, high-performance and general purpose distributed laboratory far environmental modeling. Expected end users may be either researchers in computational environmental sciences, whom a standard interface to access existing and distributed resources (database, models, visualization tools, parallel computers and virtual organisation's collaborative community facilities) is provided, or ordinary citizens who can access the results of operational runs of the integrated system far obtaining short-scale forecasts using a web-based interface. Presently, the application continuously supplies real-time forecasts and scenario analysis far both weather and air quality and it is interactively serviceable via a dedicated web portal

[en] In this paper, the static response of three-dimensional beams made of functionally graded materials is investigated through a family of hierarchical one-dimensional finite elements. A wide variety of elements is proposed differing by the kinematic formulation and the number of nodes per elements along the beam axis. Elements’ stiffness matrix and load vector are derived in a unified nuclear form that does not depend upon the a priori expansion order over the cross-section nor the finite element approximation along the beam axis. Results are validated towards three-dimensional finite element models as well as equivalent Navier-type analytical solutions. The numerical investigations show that accurate and efficient solutions (when compared with full three-dimensional FEM solutions) can be obtained by the proposed family of hierarchical one-dimensional elements’ family

[en] The southern provinces of Sudan Equatoria, Bahr el Ghazal and el Buheyrat have been investigated by geological and geochemical methods for uranium and thorium. Results of radiometric measurements permitted the identification of a target area for follow-up work, favourable to host a roll-type uranium deposit. (orig.)

[en] This paper proposes several axiomatic refined theories for the linear static analysis of beams made of functionally graded materials. A bi-directional variation upon the cross-section is accounted for. Via a unified formulation, a generic N-order approximation is assumed for the displacement unknown variables over the beam cross-section. The governing differential equations and the boundary conditions are derived in terms of a fundamental nucleo that does not depend upon the approximation order. A Navier type, closed form solution is adopted. Beams undergo bending and torsional loadings. Deep beams are investigated. Comparisons with three-dimensional finite element models are given. The numerical investigation shows that the proposed unified formulation yields the complete three-dimensional displacement and stress fields as long as the appropriate approximation order is considered.

[en] The dispersion of inorganic particles within polymeric materials is an extensively used method to enhance their mechanical properties. One of the major challenges in the simulation of polymer composites is to model the uneven surface of the fillers which strongly affects the dynamics of the adsorbed polymers and consequently the macroscopic mechanical properties of the final composite. Here we propose a new multiscale approach that, using experimental adsorption data, constructs the filler surface to statistically reproduce the surface defects. We use this approach to analyse the structure and dynamics of highly entangled polyisoprene melt in contact with different realistic carbon black samples. We show that the presence of the heterogeneous surface has a negligible influence on the structure of the polymer chains but a major effect on their dynamics and the surface wettability. (paper)

[en] The present work is carried out in the framework of a National Italian Project, whose aim is the assessment of innovative physical non-destructive techniques applied to archaeology. Towards this end, some archaeological artefacts have been studied by our group, in collaboration with the National Museum of Altino (VE) and EniTecnologie S.p.A. The objects come from the excavations in Altino, near Venice, where at least three different historical layers are present, corresponding to ages starting from approximately VII century B.C. In particular, in this work the results of neutron tomography investigations on three I-II century A.D. glass fragments are reported. The experiments were performed at the cold neutron radiography facility CONRAD at HMI (Berlin). For the 3D tomographical reconstruction of the sample, 200 projections were collected while the sample was rotated around a defined axis. The rotation interval was 180 degrees. The results show that the technique is able to reconstruct well the structural features of the investigated objects such as, in particular, highly absorbing zones and the presence of defects in the bulk