Results 71 to 80 of about 2,739,672 (219)
Acoustical properties of double porosity granular materials [PDF]
, 2011 Granular materials have been conventionally used for acoustic treatment due to their sound absorptive and sound insulating properties. An emerging field is the study of the acoustical properties of multiscale porous materials.
Umnova, O, Venegas, R
core +1 more source
Characteristics of developed flexible polyurethane foams reinforced with coconut coir fibres and recycled tyres [PDF]
, 2012 Flexible Polyurethane (PU) foam is generally used in seat cushions of automotive seating for comfort and supporting the occupants. However, due to the demand for more comfortable compartment; seat cushions are now designed for better riding comfort
Chan, Wen Shan
core
Photodarkening of amorphous selenium under high pressure
, 2002 The photodarkening phenomena of amorphous Se have been studied by the optical absorption coefficient, sound velocity and attenuation measurements. The light illumination at low temperatures induces the photodarkening, and the photodarkened state is ...
Endo, Hirohisa +4 more
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Probing Topological Superconductors with Sound Waves [PDF]
arXiv, 2015 A new method is introduced for probing Topological Superconductors. The integration of the superconding fermions generates a topological $\mathbf{Chern-Simons}$ sound action . Dislocations induce Majorana zero modes inside the sample, resulting in a new Hamiltonian which couple the Majorana modes, the electron field and the non-Abelian strain field
arxiv
The contribution of molecular relaxation in nitrogen to the absorption of sound in the atmosphere [PDF]
Results and statistical analysis are presented for sound absorption in N2-H2O binary mixtures at room temperature. Experimental procedure, temperature effects, and preliminary results are presented for sound absorption in N2-H2O binary mixtures at ...
Meredith, R. W., Zuckerwar, A. J.
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Sound absorption by perforated walls along boundaries [PDF]
arXiv, 2020 We analyze the Helmholtz equation in a complex domain. A sound absorbing structure at a part of the boundary is modelled by a periodic geometry with periodicity $\varepsilon>0$. A resonator volume of thickness $\varepsilon$ is connected with thin channels (opening $\varepsilon^3$) with the main part of the macroscopic domain.
arxiv
Nonlinear excitation of second sound in quantum solutions He3-He4 due to light wave absorption [PDF]
arXiv, 2007 Nonlinear excitation of second sound in superfluid solutions He3-He4 by light waves due to their absorption is discussed. Nonlinear wave equations that model the interaction of second-sound waves with light waves are derived, the expression for the nonlinear interaction length is obtained and an order-of-magnitude numerical estimate of the distance at ...
arxiv
Velocity and absorption coefficient of sound waves in classical gases [PDF]
arXiv, 2018 Velocity and absorption coefficient of the plane sound waves in classical gases are obtained by solving the Boltzmann kinetic equation. This is done within the linear response theory as a reaction of the single-particle distribution function to a periodic external field.
arxiv
In situ sound absorption estimation with the discrete complex image source method [PDF]
arXivEstimating the sound absorption in situ relies on accurately describing the measured sound field. Evidence suggests that modeling the reflection of impinging spherical waves is important, especially for compact measurement systems. This article proposes a method for estimating the sound absorption coefficient of a material sample by mapping the sound ...
arxiv
Reviewed here is the current state of knowledge with respect to each basic mechanism of sound propagation in the atmosphere and how each mechanism changes the spectral or temporal characteristics of the sound received at a distance from the source.
Daigle, Gilles A., Embleton, Tony F. W.
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