Measurement of Acoustic Impedance and Sound Absorption Performance of a Perforated Plate with a Backing Cavity at a High Sound Pressure Level

2016 ◽  
Vol 2016.26 (0) ◽  
pp. 118
Author(s):  
Daisuke SHIRAGA ◽  
Masaharu NISHIMURA ◽  
Tonau NAKAI ◽  
Tomonobu GOTO ◽  
Shinji AKAMATSU ◽  
...  
Keyword(s):  
Sound Pressure Level ◽  
Acoustic Impedance ◽  
Sound Absorption ◽  
Sound Pressure ◽  
Perforated Plate ◽  
Pressure Level ◽  
Absorption Performance ◽  
High Sound

Research of Possibilities of Using the Recycled Materials Based on Rubber and Textiles Combined with Vermiculite Material in the Area of ​​Noise Reduction

2014 ◽  
Vol 1001 ◽  
pp. 171-176 ◽  
Author(s):  
Pavol Liptai ◽  
Marek Moravec ◽  
Miroslav Badida
Keyword(s):  
Absorption Coefficient ◽  
Standing Wave ◽  
Sound Pressure Level ◽  
Sound Absorption ◽  
Sound Pressure ◽  
Sound Level ◽  
Pressure Level ◽  
Sound Absorption Coefficient ◽  
Physical Parameters ◽  
Materials Research

This paper describes possibilities in the use of recycled rubber granules and textile materials combined with vermiculite panel. The aim of the research is the application of materials that will be absorbing or reflecting sound energy. This objective is based on fundamental physical principles of materials research and acoustics. Method of measurement of sound absorption coefficient is based on the principle of standing wave in the impedance tube. With a sound level meter is measured maximum and minimum sound pressure level of standing wave. From the maximum and minimum sound pressure level of standing wave is calculated sound absorption coefficient αn, which can take values from 0 to 1. Determination of the sound absorption coefficient has been set in 1/3 octave band and in the frequency range from 50 Hz to 2000 Hz. In conclusion are proposed possibilities of application of these materials in terms of their mechanical and physical parameters.

scholarly journals So Small, So Loud: Extremely High Sound Pressure Level from a Pygmy Aquatic Insect (Corixidae, Micronectinae)

PLoS ONE ◽  
2011 ◽  
Vol 6 (6) ◽  
pp. e21089 ◽  
Author(s):  
Jérôme Sueur ◽  
David Mackie ◽  
James F. C. Windmill
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Aquatic Insect ◽  
Pressure Level ◽  
High Sound

scholarly journals Liner Impedance Eduction Under Shear Grazing Flow at a High Sound Pressure Level

AIAA Journal ◽  
2020 ◽  
Vol 58 (3) ◽  
pp. 1107-1117 ◽  
Author(s):  
V. Lafont ◽  
F. Méry ◽  
R. Roncen ◽  
F. Simon ◽  
E. Piot
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Grazing Flow ◽  
High Sound

scholarly journals Termination impedance of open-ended cylindrical tubes at high sound pressure level

2004 ◽  
Vol 332 (4) ◽  
pp. 299-304 ◽  
Author(s):  
Mérouane Atig ◽  
Jean-Pierre Dalmont ◽  
Joël Gilbert
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Cylindrical Tubes ◽  
High Sound

Acoustical absorptive properties of meltblown nonwovens for textile machinery

2020 ◽  
pp. 004051752098046
Author(s):  
Magdi El Messiry ◽  
Gajanan Bhat ◽  
Affaf Eloufy ◽  
Samar Abdel Latif ◽  
Yasmin Ayman
Keyword(s):  
Sound Pressure Level ◽  
Sound Absorption ◽  
Sound Pressure ◽  
Noise Exposure ◽  
Fiber Diameter ◽  
Noise Pollution ◽  
Pressure Level ◽  
The Body ◽  
Poly Lactic Acid ◽  
Average Fiber Diameter

Noise pollution is one of the harmful physical sources in the textile industry, which is among those industries that are faced with noise exposure problems. The results of environmental sound measurements at modern textile mills have shown that the sound pressure level varied from 95 to 130 dB, where the highest sound pressure level was at weaving machines. Textile insulation materials can be fitted in order to decrease sound pollution at a low cost. The objective of this work is to design a sound absorber that can be fixed to the body of the machines, at the point of the noise generation, to reduce noise pollution. Poly(lactic acid) (PLA), which is an environmentally friendly material, was used to produce different samples of meltblown nonwoven absorbers to be used for damping the noise of textile machinery. PLA meltblown nonwoven fabric with the areal density of 16.7 g/m2, average fiber diameter of 1.1 µm, mean pore diameter of 9.8 µm and thickness of 0.27 mm exhibited significant sound absorption. The sample with the smallest average fiber diameter among those investigated had the highest damping effect: 23.95, 41.29 and 29.32 dBA at frequencies of 400, 1000 and 1500 Hz, respectively. Our goal is to have a practical tool that accurately evaluates the absorber sound damping under the actual running conditions of the textile machinery. The design of the absorber from one layer of the PLA meltblown nonwoven over a rigid polyurethane foam sheet had an excellent sound absorption property.

scholarly journals Liner Impedance Eduction under shear grazing flow for high sound pressure level

2019 ◽  
Author(s):  
Fabien Mery ◽  
Victor Lafont ◽  
Remi Roncen ◽  
Frank Simon ◽  
Estelle Piot
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Grazing Flow ◽  
High Sound

scholarly journals Selection of Level-Dependent Hearing Protectors for Use in An Indoor Shooting Range

2019 ◽  
Vol 16 (13) ◽  
pp. 2266 ◽  
Author(s):  
Rafal Mlynski ◽  
Emil Kozlowski
Keyword(s):  
Sound Pressure Level ◽  
Impulse Noise ◽  
Sound Pressure ◽  
Pressure Level ◽  
Shooting Range ◽  
Noise Parameters ◽  
The People ◽  
Hearing Protectors ◽  
High Sound ◽  
Selection Of

The high sound pressure level generated by impulse noise produced in an indoor shooting range makes it necessary to protect the hearing of the people it affects. Due to the need for verbal communication during training at a shooting range, level-dependent hearing protectors are useful. The objective of this study was to answer the question of whether it is possible to properly protect the hearing of a shooting instructor using level-dependent hearing protectors. The noise parameters were measured in the places where the instructor was present at the shooting range. The division of a specific group of trained shooters into subgroups consisting of three or six simultaneously shooting individuals did not significantly affect the exposure of the shooting instructor to the noise. An assessment of noise reduction was carried out for eight models of earmuffs and two variants of earplugs, using computational methods for the selection of hearing protectors. Among the noise parameters, both the A-weighted equivalent sound pressure level and the C-weighted peak sound pressure level were taken into account. Depending on the assessment criterion adopted, a sufficient reduction in impulse noise was provided by either four or six out of the 10 hearing protectors included in the study.

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