Articolo in rivista

An anisotropic eigenvalue problem of Stekloff type and weighted Wulff inequalities

We study the Stekloff eigenvalue problem for the so-called pseudo p-Laplacian operator. After proving the existence of an unbounded sequence of eigenvalues, we focus on the first nontrivial eigenvalue ?, providing various equivalent characterizations for it. We also prove an upper bound for ? in…

General velocity, pressure, and initial condition for two-dimensional and three-dimensional lattice Boltzmann simulations

In this paper, an alternative approach to implement initial and boundary conditions in the lattice Boltzmann method is presented. The main idea is to approximate the nonequilibrium component of distribution functions as a third-order power series in the lattice velocities and formulate a procedure…

A Sobolev inequality with reciprocal weights

We give a Sobolev inequality with the weight K(x) belonging to the class A_2\cap G_n for the function |u|^t and the weight K(x)^{-1} for |u|^2. The constant in the relevant inequality is seen to depend on the G_n and A_2 constants of the weight.

Horizontal thermocapillary convection of SCN: Steady state, instabilities and transition to chaos

Spontaneous motility of passive emulsion droplets in polar active gels

We study by computer simulations the dynamics of a droplet of passive, isotropic fluid, embedded in a polar active gel. The latter represents a fluid of active force dipoles, which exert either contractile or extensile stresses on their surroundings, modelling for instance a suspension of…

The action of Volterra integral operators with highly singular kernels on Holder continuous, Lebesgue and Sobolev functions

For kernels zi which are positive and integrable we show that the operator g bar right arrow J(v)g = integral(x)(0) v(x-s)g(s)ds on a finite time interval enjoys a regularizing effect when applied to Holder continuous and Lebesgue functions and a "contractive" effect when applied to Sobolev…

A fluid dynamics model of the growth of phototrophic biofilms

A system of nonlinear hyperbolic partial differential equations is derived using mixture theory to model the formation of biofilms. In contrast with most of the existing models, our equations have a finite speed of propagation, without using artificial free boundary conditions. Adapted numerical…

Bounding Vertex Coloring by Truncated Multistage Branch and Bound

Questo lavoro si occupa di graph coloring. In particolare viene proposto un algoritmo di branch and bound troncato in grado di calcolare buoni lower bound sul numero cromatico di un grafo e spesso fornisce la soluzione ottima.

Formation of calcium phosphate nanoparticles in the presence of carboxylate molecules: a time-resolved in situ synchrotron SAXS and WAXS study

In this work we have studied in situ the formation and growth of calcium phosphate (CaP) nanoparticles (NPs) in the presence of three calcium-binding carboxylate molecules having different affinities for Ca2+ ions: citrate (Cit), hydroxycitrate (CitOH), and glutarate (Glr). The formation of CaP NPs…

Structural and dynamical properties of methane clathrate hydrates from molecular dynamics: Comparison of atomistic and more coarse-grained potential models

In an attempt to study the accuracy and utility of 'coarse grained' models for methane-clathrate systems, molecular-dynamics simulations were run for three different potential models. One was fully atomistic of TIP4P water and fully atomistic methane, the next model was atomistic SPC water and…