The term Hadley flow is used in a general sense to describe buoyant flows driven by an externally-imposed temperature gradient inclined to the vertical. The thermal instability of the Hadley flow in a fluid-saturated horizontal porous layer has been widely studied in the literature during the past three decades. Recently, further results have been obtained on this subject, by investigating the effects of the boundary conditions, the heterogeneity of the porous medium, and the inclination of the layer to the horizontal. The main numerical and analytical results obtained will be surveyed and discussed.

Starting from experimental results and first-principle simulations we have developed a transport model for amorphous chalcogenides based upon a hopping process among traps. The conduction mechanism is suitably modeled by means of a generalization of the variable-range hopping, and studied stochastically through Monte Carlo simulations. The transition rates available in the literature have been modified by incorporating the effects of the local electric field. The improved model is able to reproduce the S-shaped current-voltage characteristics of these materials. Simulations have shown that the snap-back effect in the J(V) curve can be ascribed to the formation of domains of opposite charges within the material close to the contact region, acting as a positive feedback for carriers. A microscopic particle description is also used to detect the formation of filaments inside the chalcogenide material.

Aim of this study is the development of a system for the measurement of frequency values of some physical variables such as the damping factor, the thickness of a structural element, the structural reverberation time and the longitudinal wave speed propagation in light brick walls. Such variables are required by the UNI EN 12354-1 normative for the analytical estimation of the sound reduction index R of monolithic elements in the laboratory. The results of the calculation, as a function of frequency, will be shown and compared with the measured values of the sound reduction index R.