Results 181 to 190 of about 1,158,358 (233)

Refractive Acoustic Devices for Airborne Sound

Physical Review Letters, 2001
It is shown that a system made of periodic distributions of rigid cylinders in air acts as a new material which allows the construction of refractive acoustic devices for airborne sound. This kind of crystal, named sonic crystal, has low impedance and transmits the sound at subsonic velocities. Here, the fabrication and characterization of a convergent
F, Cervera, L, Sanchis, J V, Sánchez-Pérez, R, Martínez-Sala, C, Rubio, F, Meseguer, C, López, D, Caballero, J, Sánchez-Dehesa   +8 more
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Acoustic cloak for airborne sound by inverse design

Applied Physics Letters, 2011
This Letter presents practical realization of a two-dimensional low loss acoustic cloak for airborne sound obtained by inverse design. The cloak consists of 120 aluminum cylinders of 15 mm diameter surrounding the cloaked object—a cylinder of diameter 22.5 cm.
García Chocano, Víctor Manuel, Sanchis, Lorenzo, Díaz Rubio, Ana, Martínez Pastor, Juan P., Llopis Pontiveros, Rafael, Cervera Moreno, Francisco Salvador, Sánchez-Dehesa Moreno-Cid, José   +6 more
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Airborne sound insulation of thin walls

The Journal of the Acoustical Society of America, 1991
Approximate analytical solutions are presented for the transmission of airborne sound through a plate between two rooms. The rooms are placed above each other and are of different size. The area of the plate is larger than the area of either room. Simple formulas are derived from the Euler–Bernoulli plate theory for the transmission due to the forced ...
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The interaction of airborne sound with the poroelastic ground

The Journal of the Acoustical Society of America, 2002
An airborne acoustic wave impinging on the surface of the ground provides a good vibrational source for investigating the near surface. Research has been carried out on the use of this type of source for landmine detection, characterization of agricultural soils, and studying the characteristics of snow and ice cover.
Craig J. Hickey, James M. Sabatier
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Coupling of airborne sound into the earth.

The Journal of the Acoustical Society of America, 2008
While a student at the University of Southwestern Louisiana in 1982, I was attracted to the Physical Acoustics Research Group at the University of Mississippi after reading a list of physical acoustics publications left by Professor Gordon Baird on a graduate student recruitment trip. I made a brief visit to UM and met Hank, Bolen, and Crum.
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Focusing of Airborne Sound by Heated Wires

Volume 11: Mechanical Systems and Control, 2008
In this paper, we discuss the mechanism of focusing airborne ultrasound using heated wires. The heated wire generated a radially stratified temperature field surrounding the wire. The temperature field subsequently caused both the sound speed in the air and the mass density of the air to become radially stratified.
Liang-Wu Cai, Mitko Angelov, Francisco Cervera, Jose´ Sa´nchez-Dehesa   +3 more
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Broadband unidirectional invisibility for airborne sound

Applied Physics Letters, 2018
We present a metafluid-based broadband cloak capable of guiding acoustic waves around obstacles along given directions while maintaining the wavefront undisturbed. The required parameter distribution of the proposed cloak is derived by coordinate transformation and practically implemented by employing the acoustic metafluid formed with periodically ...
Weiwei Kan, Mengping Guo, Zhonghua Shen
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Airborne sound insulation and graphical indices

Journal of Sound and Vibration, 1982
Abstract The use of graphical indices is interpreted as an approximate approach to the estimation of sound insulation performance of building elements. Differences of weighted sound pressure levels are considered as quantitative measures for subjective sound insulation. The indices considered are formed by shifting a reference curve until the highest
J. Parmanen, H.T. Tuominen
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Laser Airborne Depth Sounding in Australia

Journal of Navigation, 1986
Australia, with its large continental shelf, requires faster and more economic methods of conducting hydrographic survey. Backed by the Royal Australian Navy an experimental programme to investigate airborne laser methods was commenced in the mid 1970s and completed in 1984.
M. F. Penny, R. H. Abbot, D. M. Phillips, B. Billard, D. Rees, D. W. Faulkner, D. G. Cartwright, B. Woodcock, G. J. Perry, P. J. Wilsen, J. Richards   +10 more
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Topology Optimized Cloak for Airborne Sound

Journal of Vibration and Acoustics, 2013
Directional acoustic cloaks that conceal an aluminum cylinder for airborne sound waves are presented in this paper. Subwavelength cylindrical aluminum inclusions in air constitute the cloak design to aid practical realizations. The positions and radii of the subwavelength cylinders are determined by minimizing scattering from the cloak-structure and ...
Jacob Andkjær, Ole Sigmund
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