Related papers: Sound Absorption in Replicated Aluminum Foam
A non-equilibrium thermodynamics model able to analyze the combined effect of diffusion and adsorption in porous materials is proposed. The model considers the coupled dynamics of the diffusive phase, described by a diffusion type equation,…
We report spectral features of far infrared electromagnetic radiation absorption in anatase TiO2 nanopowders which we attribute to absorption by acoustic phonon modes of nanoparticles. The frequency of peak excess absorption above the…
In recent years, metamaterials have gained considerable attention as a promising material technology due to their unique properties and customizable design, distinguishing them from traditional materials. This article delves into the value…
A technique is proposed that uses a multi-scale approach to calculate transport properties of compressed felts using only image analysis and numerical calculations. From the image analysis fiber diameter distribution and fiber orientation…
We calculate numerically the normal modes of vibrations in 3D jammed packings of soft spheres as a function of the packing fraction and obtain the energy diffusivity, a spectral measure of transport that controls sound propagation and…
Fabrication, characterization, and analysis of an ultra-broadband lithography-free absorber is presented. An over 94% average absorption is experimentally achieved in the wavelength range of 450-1400 nm. This ultra-broadband absorption is…
Granular materials can fail through spontaneous events like earthquakes or brittle fracture. However, measurements and analytic models which forecast failure in this class of materials, while of both fundamental and practical interest,…
The absorption coefficient for surface acoustic waves in a piezoelectric insulator in contact with a GaAs/AlGaAs heterostructure (with two-dimensional electron mobility $\mu= 1.3\times 10^5 cm^2/V\cdot s)$ at T=4.2K) via a small gap has…
Direct modeling of porous materials under shock is a complex issue. We investigate such a system via the newly developed material-point method. The effects of shock strength and porosity size are the main concerns. For the same porosity,…
Nanoporous gold (npAu) has emerged as a potential candidate for many optical applications exploiting its large surface to volume ratio and high broadband absorption. However, the physical origin of its enhanced visible and near infrared…
The equations of motion in a macroscopically inhomogeneous porous medium saturated by a fluid are derived. As a first verification of the validity of these equations, a two-layer rigid frame porous system considered as one single porous…
This work presents a data-driven approach to estimating the sound absorption coefficient of an infinite porous slab using a neural network and a two-microphone measurement on a finite porous sample. A 1D-convolutional network predicts the…
Structured metamaterials are at the core of extensive research, promising for acoustic and thermal engineering. Nevertheless, the computational cost required for correctly simulating large systems imposes to use a continuous model to…
Liquid adsorption in nanoporous materials induces their deformation due to strong capillary forces. The linear relationship between the liquid pressure and the solid strain (pore-load modulus) provides an experimental technique to determine…
A procedure for measuring material thickness by means of necessarily-long acoustic wavelengths is examined. The approach utilizes a temporal phase lag caused by the impulse time of wave momentum transferred through a thin layer that is much…
The disjoining pressure isotherm in foam films is theoretically studied and an important contribution of adsorption is discovered. On the basis of the interfacial thermodynamics an adsorption disjoining pressure component is derived, which…
An active dissipative process organizes auditory frequency analysis in the mammalian cochlea. A minimal active beam model reveals that a spatially varying viscous coupling operator, $\partial_{xx}\kappa\partial_{xx}$, generates dissipative…
The propagation of a surface acoustic wave (SAW) on GaAs/AlGaAs heterostructures is studied in the case where the two-dimensional electron gas (2DEG) is subject to a strong magnetic field and a smooth random potential with correlation…
Acoustic emission is used here to study melting and solidification of embedded indium particles in the size range of 0.2 to 3 um in diameter and to show that dislocation generation occurs in the aluminum matrix to accommodate a 2.5% volume…
Using molecular dynamics simulation, we study acoustic resonance in low-temperature glass by applying a small periodic shear at a boundary wall. Shear wave resonance occurs as the frequency $\omega$ approaches $\omega_\ell= \pi…