Ricerc@Sapienza

We realize steady curved shapes from homogeneous hydrogel flat structures which are in contact with two environments at different chemical conditions. We numerically investigate the behaviour of beam-like and plate-like structures during the transient state, which realize osmotic pumps. Through numerical experiments, we determine the relationship between the difference in the chemical potentials at the top and bottom of a beam and the curvature of the bent beam as well as the Gaussian curvature of a spherical cap morphed from a flat plate.

The dynamical behavior of a mono-dimensional bar with distributed microcracks is addressed in terms of free and forced wave propagation. The multiscale model, derived from a generalized continuum formulation, accounts for the microstructure by means of a microdisplacement variable, added to the standard macrodisplacement, and of internal parameters representing density and length of microcracks. The influence of coupling between micro- and macrodisplacement overall response on the system is discussed, as well as the effect of the damage parameters on the propagating waves.

Size-dependent structural behavior of inflected Timoshenko elastic nano-beams is investigated by nonlocal continuum mechanics. An innovative stress-driven integral model of elasticity is conceived by swapping source and output fields of Eringen's strain-driven theory. Unlike Eringen's model, the stress-driven nonlocal integral formulation leads to well-posed structural problems. Solution uniqueness and continuous dependence on data are thus ensured.

We present a finite element discrete model for pantographic lattices, based on a continuous Euler–Bernoulli beam for modeling the fibers composing the pantographic sheet. This model takes into account large displacements, rotations and deformations; the Euler–Bernoulli beam is described by using nonlinear interpolation functions, a Green–Lagrange strain for elongation and a curvature depending on elongation. On the basis of the introduced discrete model of a pantographic lattice, we perform some numerical simulations.

Laser-driven particle acceleration, obtained by irradiation of a solid target using an ultra-intense (I>1018W/cm2) short-pulse (duration

We present in this paper the proposal of an experimental test at DAΦNE of the positron-ring-plus-target scheme foreseen in the Low EMittance Muon Accelerator. This test would be a validation of the on-going studies for LEMMA and it would be synergic with other proposals at DAΦNE after the SIDDHARTA-2 run. We discuss the beam dynamics studies for different targets inserted in a proper location through the ring, i.e. where the beam is focused and dispersion-free.

Electronic properties and lattice vibrations are expected to be strongly correlated in metal-halide perovskites, due to the soft fluctuating nature of their crystal lattice. Thus, unveiling electron-phonon coupling dynamics upon ultrafast photoexcitation is necessary for understanding the optoelectronic behavior of the semiconductor. Here, we use impulsive vibrational spectroscopy to reveal vibrational modes of methylammonium lead-bromide perovskite under electronically resonant and non-resonant conditions.

In this paper, we describe QUBIC, an experiment that will observe the polarized microwave sky with a novel approach, which combines the sensitivity of state-of-the-art bolometric detectors with the systematic effects control typical of interferometers. QUBIC's unique features are the so-called "self-calibration", a technique that allows us to clean the measured data from instrumental effects, and its spectral imaging power, i.e., the ability to separate the signal into various sub-bands within each frequency band. QUBIC will observe the sky in two main frequency bands: 150GHz and 220 GHz.

Kinetic Inductance Detectors (KIDs) are superconductive low-temperature detectors useful for astrophysics and particle physics. We have developed arrays of lumped elements KIDs (LEKIDs) sensitive to microwave photons, optimized for the four horn-coupled focal planes of the OLIMPO balloon-borne telescope, working in the spectral bands centered at 150 GHz, 250 GHz, 350 GHz, and 460 GHz. This is aimed at measuring the spectrum of the Sunyaev-Zel'dovich effect for a number of galaxy clusters, and will validate LEKIDs technology in a space-like environment.