Free‐field reciprocity calibration of microphones in ultrasonic frequency range

2005 ◽  
Vol 118 (3) ◽  
pp. 1944-1945
Author(s):  
Nourreddine Bouaoua ◽  
Thomas Fedtke ◽  
Volker Mellert
Keyword(s):  
Free Field ◽  
Ultrasonic Frequency ◽  
Frequency Range ◽  
Reciprocity Calibration

Method of Testing of Sound Absorption Properties of Materials Intended for Ultrasonic Noise Protection

2013 ◽  
Vol 38 (2) ◽  
pp. 191-195 ◽  
Author(s):  
Dariusz Pleban
Keyword(s):  
Sound Absorption ◽  
Free Field ◽  
Tone Burst ◽  
Mineral Wool ◽  
Frequency Range ◽  
Absorption Properties ◽  
Open Cell Foam ◽  
Properties Of Materials ◽  
Cell Foam

Abstract Efficient ultrasonic noise reduction by using enclosures requires the knowledge of absorbing properties of materials in the frequency range above 4 kHz. However, standardized methods enable determination of absorption coefficients of materials in the frequency range up to 4 kHz. For this reason, it is proposed to carry out measurements of the sound absorption properties of materials in the free field by means of a tone-burst technique in the frequency range from 4 kHz to 40 kHz at angles of incidence varying from 0° to 60°. The absorption coefficient of a material is calculated from the reflection coefficient obtained by reflecting a tone-burst from both a perfectly reflecting panel and a combination of this panel and the sample of the tested material. The tests results show that mineral wool and polyurethane open-cell foam possess very good absorbing properties in this frequency range.

Finite Element Analysis of SiCp/Al Model of Unit Cell during Ultrasonic Vibration Scratching

2016 ◽  
Vol 693 ◽  
pp. 1022-1029
Author(s):  
G.Q. Liang ◽  
Ping Fa Feng ◽  
Jian Fu Zhang
Keyword(s):  
Finite Element ◽  
Maximum Amplitude ◽  
Element Model ◽  
Ultrasonic Frequency ◽  
Frequency Range ◽  
Element Analysis ◽  
Scale Modeling ◽  
Sic Particles ◽  
Significant Damage ◽  
Extent Of Damage

In this paper, finite element model of SiCp /Al single cell body and single diamond particles were established by cross-scale modeling method. The results shows that the extent of damage of SiC particles increased with the increase of amplitude and frequency; The integrity of SiC particles are still better under the ultrasonic frequency 20000 Hz and the maximum amplitude 5um,so the optimal frequency range of ultrasonic scratch is (20000-30000)Hz. As for 22000 Hz, the integrity of SiC particles was better under the amplitude 4um,while the SiC particles have a significant damage in the border area under the amplitude 5um,so the best frequency and amplitude for ultrasonic scratches are: 22000 Hz and 4 um.

International comparison of free-field hydrophone calibrations in the frequency range 10 kHz to 315 kHz

Metrologia ◽  
1999 ◽  
Vol 36 (4) ◽  
pp. 287-296 ◽  
Author(s):  
S P Robinson ◽  
G J Green ◽  
R C Preston ◽  
L Peirlinckx ◽  
L Kofoed ◽  
...  
Keyword(s):  
International Comparison ◽  
Free Field ◽  
Frequency Range

SEISMIC DECOUPLING FOR EXPLOSIONS IN SPHERICAL UNDERGROUND CAVITIES

Geophysics ◽  
1961 ◽  
Vol 26 (6) ◽  
pp. 772-799 ◽  
Author(s):  
William M. Adams ◽  
DeWitt C. Allen
Keyword(s):  
Spherical Cavity ◽  
Seismic Waves ◽  
Free Field ◽  
Salt Mine ◽  
Cavity Pressure ◽  
Frequency Range ◽  
Overburden Pressure ◽  
Underground Cavities ◽  
Order Of Magnitude ◽  
Surface Measurements

A series of paired explosions in a salt mine near Winnfield, Louisiana, has been conducted to test a theory by A. L. Latter concerning seismic decoupling by underground cavities. The theory predicted a decoupling of 130. Free‐field and surface measurements from an explosion in either a 6‐ft‐ or a 15‐ft‐radius spherical cavity were compared with similar measurements from a completely tamped explosion of equal size. Shot sizes were from 20 pounds to a ton. Surface measurements were made out to 100 km and covered the frequency range from 0.05 to 100 cps. The experiment confirmed that decoupling does occur. For explosions that produce an average cavity pressure up to one‐fifth and possibly more of the lithostatic overburden pressure, seismic waves were decoupled by more than 100, i.e., two orders of magnitude. Even for explosions producing an average cavity pressure of six times the lithostatic overburden pressure, the seismic waves were decoupled by 20—more than a full order of magnitude. Minimum decoupling factors as a function of frequency are presented.

Reciprocity calibration of hydrophones at various temperatures in the MHz frequency range

2004 ◽  
Vol 115 (5) ◽  
pp. 2377-2377
Author(s):  
Cecille Labuda ◽  
Charles C. Church ◽  
Jason Raymond
Keyword(s):  
Frequency Range ◽  
Reciprocity Calibration

The measurement of reflection coefficient dispersion in the ultrasonic frequency range

2019 ◽  
Author(s):  
Min Li ◽  
Genyang Tang ◽  
Chunhui Dong ◽  
Liming Zhao ◽  
Chao Sun ◽  
...  
Keyword(s):  
Reflection Coefficient ◽  
Ultrasonic Frequency ◽  
Frequency Range
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