Efficiency of an absorber involving a nonlinear membrane driven by an electro-acoustic device

2017 ◽  
Vol 141 (5) ◽  
pp. 3644-3644
Author(s):  
Pierre-Yvon Bryk ◽  
Sergio Bellizzi ◽  
Renaud Côte
2010 ◽  
Vol 29 (1) ◽  
pp. 25-29 ◽  
Author(s):  
K.A.P. Siriwardena ◽  
L.C.P. Fernando ◽  
N. Nanayakkara ◽  
K.F.G. Perera ◽  
A.D.N.T. Kumara ◽  
...  
Keyword(s):  

2018 ◽  
Vol 14 (2) ◽  
pp. NP1-NP2

James E.K. Parker, Towards an Acoustic Jurisprudence: Law and the Long Range Acoustic Device, Law, Culture and the Humanities (LCH). DOI: 10.1177/1743872115615502 The following corrections have been made to the article: Under heading III.1, another paragraph has been added. This paragraph begins ‘Whereas normal loudspeaker works…’ Under heading III.2, a paragraph has been edited: ‘In effect, what ATC did with the LRAD…’ Under heading III.2, the first sentence of the last paragraph has been expanded to clarify that the G-20 summit was held in Pittsburgh: The LRAD seems to have been used by police for the first time in Georgia in 2007, before receiving its first and most notorious outing on American soil in September 2009 at protests relating to the G-20 Summit being held in Pittsburgh.66 Under heading III.4, the sentence below in the second paragraph has been changed as follows: The law of property provides the conditions for the circulation and ownership of knowledge that enable developments in the science of acoustics at a US university in the 1950s to re-emerge as failed commercial prototypes in Japan in the 1980s only to be taken up again in 1996 by ACT before being patented, trademarked and marketed first as HSS® and then as the LRAD.82 Under heading III.4, the following has been added to the end of the paragraph ‘If the LRAD was originally imagined…’: Not that the presiding judge in the Toronto case would know however. In his discussion of a deposition by Professor David Wood, of Queen’s University, relating to ‘videos posted on the internet’ documenting the LRAD’s use at Pittsburgh, Justice Brown notes that, ‘unfortunately, Professor Wood did not attach any of those media reports or videos as exhibits to his affidavit. As a result, I cannot attach any weight to his statements.’93 Indeed, it’s not clear that any recordings of an LRAD in action were ever actually played in court. As far as I know, the LRAD has yet to feature in the ‘judicial soundscape’. In the conclusion the word ‘copyright’ has been replaced with ‘intellectual property’: The LRAD is the product of diverse institutions, jurisdictions and areas of doctrine, stretching from the law of intellectual property through the law of war to constitutional and labor law. The references and reference numbers have been updated accordingly. All the subsequent versions of the article will be corrected.


Procedia CIRP ◽  
2013 ◽  
Vol 5 ◽  
pp. 290-293 ◽  
Author(s):  
Kanako Harada ◽  
Takashi Azuma ◽  
Tomoyuki Inoue ◽  
Toshiaki Takeo ◽  
Shu Takagi ◽  
...  

Resonance ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 264-280
Author(s):  
John Vilanova

This research explores a set of sound technologies deployed during the 2011 Occupy Wall Street protests in New York City’s Zuccotti Park. It examines the People’s Microphone, the Long Range Acoustic Device (LRAD) sound cannon, the drum circle, and the noise complaint. Deepening understandings of their places within the contemporary urban soundscape and their use during the protests, it uses historical research, textual analysis, and qualitative discourse analysis methods to explore the technologies within a larger framework of the city’s discourses around (in)appropriate sound and action. Its findings suggest that each individual technology was evidence for the nature of its user in a way that presaged how the conflict would play out. The microphone epitomized the ideology (and fragility) of the hyper-democratic Occupiers’ ethos. The LRAD suggested the state’s superlative sonic capability and its “monopoly on the legitimate use of noise.” And the drum circles and noise complaints that followed ultimately showed the ways “noise-making” is better understood as a discursive construction that delegitimizes sound. Together, they suggest the ways the hegemonic soundscape serves the status quo. The essay also elaborates a taxonomy of sonic terms, specifically exploring volume, amplification, and noise-making as terms that explain the dynamics of sound during protest. It offers scholars of media activism a toolkit for sound studies that gets at the dynamics and structures of sonic power and explores the way sound-making is a key battleground of modernity. Sound conventions are a way that contemporary society is codified, legislated, and contested.


Author(s):  
Guanghua Wu ◽  
Yibo Ke ◽  
Lin Zhang ◽  
Meng Tao

Abstract Acoustic metamaterials have high potential in diverse applications, including acoustic cloaking, sound tunneling, wavefront reshaping, and sound insulation. In the present study, new metamaterials consisting of spatial coiled units are designed and fabricated to manipulate sound waves in the range 0-1600 Hz. The effective acoustic properties and band diagrams are studied. The simulation and experimental results demonstrate that the metamaterials provide an effective and feasible approach to design acoustic device such as sound cloaking and insulators.


HardwareX ◽  
2019 ◽  
Vol 6 ◽  
pp. e00073 ◽  
Author(s):  
Andrew P. Hill ◽  
Peter Prince ◽  
Jake L. Snaddon ◽  
C. Patrick Doncaster ◽  
Alex Rogers
Keyword(s):  
Low Cost ◽  

2020 ◽  
Vol 317 ◽  
pp. 23-33 ◽  
Author(s):  
Estelle Beguin ◽  
Michael D. Gray ◽  
Keiran A. Logan ◽  
Heather Nesbitt ◽  
Yingjie Sheng ◽  
...  

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1138 ◽  
Author(s):  
Jianwang Shao ◽  
Tao Zeng ◽  
Xian Wu

As a new approach to passive noise control in low frequency domain, the targeted energy transfer (TET) technique has been applied to the 3D fields of acoustics. The nonlinear membrane absorber based on the TET can reduce the low frequency noise inside the 3D acoustic cavity. The TET phenomenon inside the 3D acoustic cavity has firstly investigated by a two degrees-of-freedom (DOF) system, which is comprised by an acoustic mode and a nonlinear membrane without the pre-stress. In order to control the low frequency broadband noise inside 3D acoustic cavity and consider the influence of the pre-stress for the TET, a general model of the system with several acoustic modes of 3D acoustic cavity and one nonlinear membrane is built and studied in this paper. By using the harmonic balance method and the numerical method, the nonlinear normal modes and the forced responses are analyzed. Meanwhile, the influence of the pre-stress of the nonlinear membrane for the TET is investigated. The desired working zones of the nonlinear membrane absorber for the broadband noise are investigated. It can be helpful to design the nonlinear membrane according the dimension of 3D acoustic cavity to control the low frequency broadband noise.


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