Existence and uniqueness of maximal regular flows for non-smooth vector fields

In this paper we provide a complete analogy between the Cauchy-Lipschitz and the DiPerna-Lions theories for ODE's, by developing a local version of the DiPerna-Lions theory. More precisely, we prove existence and uniqueness of a maximal regular flow for the DiPerna-Lions theory using only local regularity and summability assumptions on the vector field, in analogy with the classical theory, which uses only local regularity assumptions. We also study the behaviour of the ODE trajectories before the maximal existence time. Unlike the Cauchy-Lipschitz theory, this behaviour crucially depends on the nature of the bounds imposed on the spatial divergence of the vector field. In particular, a global assumption on the divergence is needed to obtain a proper blow-up of the trajectories.Comment: 38 page

I.S.Mu.L.T - Rotator cuff tears guidelines

Despite the high level achieved in the field of shoulder surgery, a global consensus on rotator cuff tears management is lacking. This work is divided into two main sessions: in the first, we set questions about hot topics involved in the rotator cuff tears, from the etiopathogenesis to the surgical treatment. In the second, we answered these questions by mentioning Evidence Based Medicine. The aim of the present work is to provide easily accessible guidelines: they could be considered as recommendations for a good clinical practice developed through a process of systematic review of the literature and expert opinion, in order to improve the quality of care and rationalize the use of resources

High-order discontinuous galerkin solution of the rans and explicit algebraic reynolds stress k-ω equations in turbomachinery flows

The objective of this work is to show the effectiveness of a high-order accurate Discontinuous Galerkin (DG) space discretization in the numerical simulation of the 3D compressible turbulent flow through a turbine cascade (MTU T106A). The turbulent flow field is computed by means of the Reynolds Averaged Navier-Stokes (RANS) equations with closure provided by the k-ω turbulence model and an Explicit Algebraic Reynolds Stress Model (EARSM). Results obtained with both models will be analysed and compared

Assessment of a high-order accurate Discontinuous Galerkin method for turbomachinery flows

In this work the capabilities of a high-order Discontinuous Galerkin (DG) method applied to the computation of turbomachinery flows are investigated. The Reynolds averaged Navier–Stokes equations coupled with the two equations k-ω turbulence model are solved to predict the flow features, either in a fixed or rotating reference frame, to simulate the fluid flow around bodies that operate under an imposed steady rotation. To ensure, by design, the positivity of all thermodynamic variables at a discrete level, a set of primitive variables based on pressure and temperature logarithms is used. The flow fields through the MTU T106A low-pressure turbine cascade and the NASA Rotor 37 axial compressor have been computed up to fourth-order of accuracy and compared to the experimental and numerical data available in the literature

Applicazione di leghe a memoria di forma per dispositivo pressoterapico

LAUREA MAGISTRAL

Studying and monitoring large landslides with persistent scatterer data

This work is focused on very slow moving landslides and the new generation of Persistent Scatterers PSI (SqueeSAR™ processing, developed by Telerilevamento Europa) that allows to increase the density and the time series quality of interferometric data. The improvement in the time series quality helps also to understand the behaviour of some processes and to have a best comparison with traditional monitoring system and/or rainfall data. The consequent aim of the research is to evaluate the potential and the limitations of PSI data for large landslide studying and monitoring. Some large landslides belonging to different geological, geomorphologic and land-use contexts and with different monitoring systems, in Western and Ligurian Alps, Langhe Hills and a portion of Northern Apennines (Oltrepò Pavese), have been analyzed. The study area is covered by 18 years of SAR data, consisting on ERS (1992- 2001) and RADARSAT platform (2003-2010). The results show that the PSI analysis is useful both on regional and local scale. At regional scale PSI allows to improve landslide inventories. At local scale the PSI joined with other data can help in the understanding landslide features and kinematics