Sand transverse dune aerodynamics: 3D Coherent Flow Structures from a computational study

The engineering interest about dune fields is dictated by the their interaction with a number of human infrastructures in arid environments. Sand dunes dynamics is dictated by wind and its ability to induce sand erosion, transport and deposition. A deep understanding of dune aerodynamics serves then to ground effective strategies for the protection of human infrastructures from sand, the so-called sand mitigation. Because of their simple geometry and their frequent occurrence in desert area, transverse sand dunes are usually adopted in literature as a benchmark to investigate dune aerodynamics by means of both computational or experimental approaches, usually in nominally 2D setups. The present study aims at evaluating 3D flow features in the wake of a idealised transverse dune, if any, under different nominally 2D setup conditions by means of computational simulations and to compare the obtained results with experimental measurements available in literature

A Multiphase First Order Model for Non-Equilibrium Sand Erosion, Transport and Sedimentation

Three phenomena are involved in sand movement: erosion, wind transport, and sedimentation. This paper presents a comprehensive easy-to-use multiphase model that include all three aspects with a particular attention to situations in which erosion due to wind shear and sedimentation due to gravity are not in equilibrium. The interest is related to the fact that these are the situations leading to a change of profile of the sand bed

Quantum discord in a spin system with symmetry breaking

We analyze the quantum discord Q throughout the low-temperature phase diagram of the quantum XY model in transverse field. We first focus on the T=0 order-disorder quantum phase transition both in the symmetric ground state and in the symmetry broken one. Besides it, we highlight how Q displays clear anomalies also at a non critical value of the control parameter inside the ordered phase, where the ground state is completely factorized. We evidence how the phenomenon is in fact of collective nature and displays universal features. We also study Q at finite temperature. We show that, close to the quantum phase transition, Q exhibits quantum-classical crossover of the system with universal scaling behavior. We evidence a non trivial pattern of thermal correlations resulting from the factorization phenomenon.Comment: 9 pages, 9 figure, Contribution to the Festschrift volume in honour of Vladimir Korepi

Solving the Sixth Painleve' Equation: Towards the Classification of all the Critical Behaviours and the Connection Formulae (October 2010)

The critical behavior of a three real parameter class of solutions of the sixth Painlev\'e equation is computed, and parametrized in terms of monodromy data of the associated $2\times 2$ matrix linear Fuchsian system of ODE. The class may contain solutions with poles accumulating at the critical point. The study of this class closes a gap in the description of the transcendents in one to one correspondence with the monodromy data. These transcendents are reviewed in the paper. Some formulas that relate the monodromy data to the critical behaviors of the four real (two complex) parameter class of solutions are missing in the literature, so they are computed here. A computational procedure to write the full expansion of the four and three real parameter class of solutions is proposed.Comment: 53 pages, 2 figure

Non-ridge-chordal complexes whose clique complex has shellable Alexander dual

A recent conjecture that appeared in three papers by Bigdeli--Faridi, Dochtermann, and Nikseresht, is that every simplicial complex whose clique complex has shellable Alexander dual, is ridge-chordal. This strengthens the long-standing Simon's conjecture that the $k$-skeleton of the simplex is extendably shellable, for any $k$. We show that the stronger conjecture has a negative answer, by exhibiting an infinite family of counterexamples.Comment: Substantial improvements. To appear on Journal of Combinatorial Theory, Series

ENVIRONMENTAL DESIGN: Nature and pathways connecting Cadorna Station and Triennale Milano

This article investigates the Master Plan measures for the environmental, cultural, and social regeneration of a highly historical and monument-dense area of Milan, by the European guidelines against climate and environment-related issues, in the framework of a competitive and efficient economy in terms of natural resources. We present several approaches to foster a dialogue on the cross-discipline character of climate-adaptive design in urban contexts as a research ground for the development of strategies and innovative solutions, as well as new cultural models to support the green transformation of anthropized environments

NETWORKED AND INTEGRATED DIGITAL PLATFORMS FOR THE UNIVERSITY SYSTEM

The paper aims to stimulate and share new opinions on the opportunity to reorganise and enhance the wide universe of digital applications to handle the Italian university system, trying to outline a forward-looking scenario considered in its structural components (teaching, research and third mission) placing people at its core. The final aim is to design networked and integrated digital platforms in collaboration with CINECA Inter-University Consortium, with the aim to submit to it the areas of intervention where it is possible and desirable to think about the development and subsequent implementation of innovative and original products, making Italian universities catch up on the most qualified international situations by fostering the transition to an open, transparent, inclusive and sustainable system

A Power Cap Oriented Time Warp Architecture

Controlling power usage has become a core objective in modern computing platforms. In this article we present an innovative Time Warp architecture oriented to efficiently run parallel simulations under a power cap. Our architectural organization considers power usage as a foundational design principle, as opposed to classical power-unaware Time Warp design. We provide early experimental results showing the potential of our proposal