Showing papers in "Applied Acoustics in 2011"

TL;DR: The work of the ISO/TC 43/SC 1 Working Group 54 as mentioned in this paper has been formed with a remit of standardization for perceptual assessment of human sound preference (in outdoor space) using questionnaires.

TL;DR: In this paper, the acoustical and flammability properties of jute fiber and felt (natural rubber latex jute composite) were measured in terms of normal specific sound absorption coefficient and sound transmission loss whereas fire retardant tests included limiting oxygen, flame propagation and smoke density test.

TL;DR: In this article, the acoustical properties of hemp concrete, a green building material, have been investigated and it is shown that the sound absorption of these materials can be controlled and significantly enhanced by means of suitable constituents and fabrication processes.

TL;DR: In this article, two types of fiber are investigated, fresh from wet market and industrial prepared mixed with binder, and two analytical models, namely, Delany-Bazley and Biot-Allard are used for analysis.

TL;DR: In this paper, a combination of natural fibres and whole reeds has been used to develop a range of sustainable sound absorbers which act very effectively across the complete audio frequency range.

TL;DR: Each measure of decay times, energy ratios, measures of sound strength and several quantities related to the spatial aspects of sound fields is discussed, illustrating particular problems with measurements in various halls.

TL;DR: Comparisons between two representative cities with different urban densities, Greater Manchester in the UK and Wuhan in China, have shown significant effects of urban morphology on the traffic noise distribution.

TL;DR: In this paper, the authors present the results of an acoustic evaluation conducted in areas adjacent to federal highway BR-116, part of which lies within the urban limits of the city of Curitiba in southern Brazil.

TL;DR: In this article, a survey and a laboratory experiment were conducted to investigate the influence of noise sensitivity on the annoyance caused by indoor residential noises and outdoor traffic noise, consistent with previous studies on transportation noise.

TL;DR: In this article, simulated annealing is proposed as a tool to solve the optimization problem of finding the best combination of the constitutive parameters of an ML-MPP providing the maximum average absorption within a prescribed frequency band.

TL;DR: A new hybrid method for automated frog sound identification, using spectral centroid, Shannon entropy and Renyi entropy is proposed, and it is found that the accuracy reduces significantly only when the noise levels higher than −20 dB.

TL;DR: A scheme to develop a noise map and noise impact assessment method using GIS has been suggested for the city of Chungju, Republic of Korea and the areas exceeding environmental noise standards were effectively evaluated through a GIS space analysis.

TL;DR: In this paper, the authors report on strategic noise mapping research conducted in Dublin, Ireland using the UK's calculation of road traffic noise (CRTN) method for calculating noise levels in the study area and highlight the significant role that certain noise mitigation measures can play in good acoustical planning.

TL;DR: In this paper, an experimentally validated analytical model has been developed in order to investigate the effect on impact sound transmission at low frequencies of location of the impact, type of floor, edge conditions, floor and room dimensions, position of the receiver and room absorption.

TL;DR: In this article, the authors quantified the error committed when using short-term noise measurements as a function of interval length measurement, and found that the difference between the shortterm noise level and L d follows a different distribution for main roads than for ordinary streets.

TL;DR: Based on the orthogonality of the sensors' location, a MUSIC algorithm in spherical space is proposed, named as SH-MUSIC, in this article, where spherical harmonics transformation is operated before MUSIC, and a better performance is obtained because SH-mUSIC utilizes the array configuration's orthogonomality.

TL;DR: In first proposed algorithm, the reference and the error signals are thresholded before being used in the update equation of FxLMP algorithm, and a modified normalized step size is proposed to improve the robustness of the Fx LMP algorithm.

TL;DR: In this article, the authors report a revealed preference study into the different effects of road traffic noise on property values in residential areas with similarly high road traffic sound levels but with what appear to be important differences in the market for different types of residential property in each area.

TL;DR: A comparison of two noise assessments in the Gdansk agglomeration in Poland is presented, based on the noise map produced by computational method for the city in 2007 and real data from continuous measurements acquired by a noise monitoring network operating in the city since 2008.

TL;DR: In this article, the authors applied shape and parametric optimization techniques in the study of reactive silencers with extended inlet and outlet ducts to improve the acoustic features of these mufflers in a specific frequency range.

TL;DR: In this article, the sound absorption characteristics of a panel sound absorber with a honeycomb in its back cavity are theoretically analyzed, and numerical results are used to discuss the variations in the sound absorbing characteristics due to the honeycomb as well as the mechanism for sound absorption.

TL;DR: In this paper, the influence of surface temperature on the acoustical behavior of a semidense asphalt pavement located in an urban area was analyzed with a trailer Tiresonic Mk4 LA2IC-UCLM rolling at a speed of 50 km/h.

TL;DR: This paper outlines the development of advanced 3D GIS tools, information technologies and how they were put into trials and implementation in Hong Kong.

TL;DR: In this paper, the potential of recycled materials made from rubber fluff for reducing impact noise was assessed according to EN ISO 140-8:1997, and the performance of these materials was compared to those of some commercially available underlays.

TL;DR: In this article, the authors investigated the relationship between environmental noise levels of secondary schools in Greater London and a set of academic achievement factors, and also determined the noise exposure of the secondary schools.

TL;DR: In this article, the hole interaction effect on the sound absorption coefficient of micro-perforated panels under high and medium sound levels was investigated and the theoretical formulations were based on a semi-empirical approach and the use of Fok's function to model the acoustic surface impedance.

TL;DR: In this paper, the authors carried out measurements to evaluate industrial noise levels, are these levels exceeded the permissible levels set by Egyptian noise standard and policy to protect public health of workers?, to examine worker's attitudes towards industrial noise, to know the relationship between industrial noise level and degree of annoyance.

TL;DR: In this paper, a 3D model was used to investigate the effect of a facade opening to the courtyard, which could lead to up to 10 dB(A) higher noise levels as compared to the noise propagating over the roof level and may prohibit the use of these courtyards as quiet areas.

TL;DR: In this paper, the feasibility of using commercially available loudspeakers as low-cost linear alternators for thermo-acoustic applications, to convert acoustic power to electricity, is investigated, in which a high intensity acoustic wave is induced by using a high power woofer, while a pair of microphones and a laser displacement sensor are used to enable acoustic power measurements.

TL;DR: In this paper, the authors investigated the effect of perforation on the sound insulation performance of multi-layer structures using a microperforated panel (MPP), which can absorb well over a wide frequency range.