Abstract
Starting from a recently developed energetic space-time weak formulation of boundary integral equations (BIEs) related to wave propagation problems defined on single and multi domains, a coupling algorithm is presented, which allows a flexible use of finite and boundary element methods as local discretization techniques, in order to efficiently treat unbounded media. The coupling is based on a weak reformulation in the energetic framework of partial differential equations associated to BIEs. Some details on quadrature schemes developed for the numerical evaluation of matrix elements in the linear system of the final time-marching procedure will be introduced and emphasis will be given to the stability analysis of the proposed energetic approach. Several numerical results on wave propagation model problems will be presented and discussed.

Abstract
In this talk I will illustrate the main results from my Phd thesis study about the estimation of the effects of deposition and resuspension
phenomena on the airborne PM10 concentration levels in Urban areas.
I will show how analytical solutions of algebraic Turbulence models have been used to describe the wind recirculation inside a urban canyon and the vehicle wakes interaction. Results from numerical simulations

of the air flow generated by single vehicles with different geometries and

velocities and the derived profile laws for deposition and resuspension

factors will be reported. Finally, pollutant dispersion results, together

with estimations of PM10 concentration levels after the implementaion

of different reduction scenarios, will be shown.

Abstract
Propongo il punto di vista che le architetture software, che siano grandi e complesse o spicciole ( quickies , come dicono gli Americani)
devono essere basate su un certo modello di riproducibilita e verificabilita .

L argomento sviluppo di software include molti aspetti di un progetto: il version control , le infrastrutture di programmazione, il controllo
dell integrita di dati e di pipeline , e anche le parti sociologiche del progetto: il modo in cui i collaboratori communicano e progettano.

Offriro esempi di progetti (tratti dalla mia cariera di astrofisico e hacker) che hanno avuto successo e di grandi disastri, e suggeriro che
il classico modello di sviluppo nel mondo del software libero e ideale per lo sviluppo di software scientifico a tutti i livelli.

Abstract
The Cahn-Hilliard (CH) equation describes the phase separation taking
place in a binary alloy subject to a rapid cooling process. More
precisely, it governs the evolution of the (relative) concentration
difference between the two components of the material. This equation
was proposed by J.W. Cahn and J.E. Hilliard in the late Fifties. Since
then it has been analyzed by many authors. Also, it has been recently
used to model other phenomena arising, for instance, in modeling tumor
growth, image segmentation and population dynamics. However, the
original CH equation has a phenomenological nature and lacks of a
rigorous justification. At the beginning of the Nineties, G. Giacomin
and J. L. Lebowitz proved that the hydrodynamic limit of a phase
segregation (separation) process is a nonlocal variant of the CH
equation. More precisely, the so-called chemical potential depends on
the concentration through a nonlocal spatial operator characterized by
a suitable interaction kernel. Thus the physically well-justified CH
equation is actually an integro-differential equation, while the
original CH equation can be viewed as its local approximation. After
an overview on the CH equation, I intend to give a (hopefully) not too
technical presentation of some recent mathematical results on the
nonlocal case.

Abstract
The talk deals with a reduced order model based on proper orthogonal decomposition (POD) applied to simulating the multi-group time-dependent neutron diffusion equation for TRIGA Mark II reactor of the University of Pavia. This real-time technique reduces the computational effort associated to the direct simulation for each perturbed neutron diffusion equation. More precisely, the reduction space is constructed from spatial solutions (snapshots) of the stationary multi-group parametrized generalized eigenvalue problem that is associated to the main problem. The smallest positive real eigenvalue of the problem contains valuable information about the status of the fission chain reaction in the nuclear reactor. The numerical experiments will be presented to demonstrate the ability to predict efficiently both the distribution of neutronic flux and the reactivity of the system.The future perspectives of the current work deal with real-time multiphysics models and an optimal a posteriori sampling of the parametrized manifold.

speakers:
Enrico Marco Ricotti, Full Professor, Department of Enery, CeSNEF- Nuclear Engineering Division Politecnico di Milano
Alberto Sartori, Phd Student, Department of Enery, CeSNEF- Nuclear Engineering Division Politecnico di Milano

referente: Davide Baroli (Phd student, MOX)

Abstract
Given a harmonic function defined on the unit ball of R^n, we discuss techniques to
obtain effective volume estimates on the tubular neighborhood of its critical sets.


We use a technique recently introduced by proff. Jeff Cheeger and Aaron Naber,
called quantitative stratification technique. It is based on approximate symmetries
of the function u at different scales. Studying how these approximate symmetries
interact with each other, we obtain the effective volume estimates.

These results
are described in a preprint available on arXiv.

We also discuss possible improvements
of the results using a refined quantitative differentiation argument and packing
estimates for semi-algebraic sets.

Abstract
It is well known that lower semicontinuity of functionals in
the supremal form F(u)=esssupx�¸ƒ¶ f(�Þu(x))is related to the
level-convexity of the supremand f . We adress the problem of
existence of solutions for the Dirichlet boundary problem in the lack
of this convexity condition relating it with some differential
inclusion problem. This is a joint work with E. Zappale.

Abstract
Algebraic geometry is the study of solutions sets to polynomial equations. Solutions that depend on an infinitesimal parameter are studied combinatorially by tropical geometry.
Tropicalization works especially well for varieties that are parametrized by monomials in linear forms. Many classical moduli spaces (for curves of low genus and few points in the plane) admit such a representation, and we here explore their tropical geometry.
Examples to be discussed include the Segre cubic, the Igusa quartic, the Burkhardt quartic, and moduli of marked del Pezzo surfaces.
Matroids, hyperplane arrangements, and Weyl groups play a prominent role. Our favorites are E6, E7 and G2.

Abstract
We wish to present some recent developments concerning the
solvability of some classes of quasilinear parabolic equations with
dynamic boundary conditions. We will describe issues from
well-posedness to the long time asymptotic behavior as time goes to
infinity (attractors, dimension estimates, etc). We will explain how
to derive new conditions which reflect an exact balance between the
internal and the boundary mechanisms involved, even when both the
nonlinear sources contribute in opposite directions. Blow up of
solutions will also be touched on.