Showing papers in "Applied Acoustics in 2012"

TL;DR: In this paper, the authors examine some of the recent advances in the parametric acoustic array (PAA) since it was first applied in air in 1983 by Yoneyama.

TL;DR: To the best of the authors’ knowledge, this is the fastest time-domain solver for modeling the room acoustics of large, complex-shaped 3D scenes that generates accurate results for both auralization and visualization.

TL;DR: In this paper, the sound absorption properties of different materials developed from ground polyurethane foam waste are studied, which are viable alternatives to conventional materials for practical applications for sound absorbing properties.

TL;DR: In this article, sound absorption properties of porous zeolite with macropores, a ceramic material fabricated by high-temperature sintering, are studied by two analytical models, Delany-Bazley model and Johnson-Allard model, where the latter one shows a better fit to the experimental results.

TL;DR: In this article, a robust FsLMS algorithm is proposed for a functional link artificial neural network (FLANN) based active noise control (ANC) system which is least sensitive to such disturbances and does not call for any prior information on the noise characteristics.

TL;DR: In this article, the results of a new absorber material obtained through thermal compression, using a residue that is currently used for its high calorific value, have been obtained.

TL;DR: In this paper, an efficient method of damping structural vibrations using the acoustic black hole effect is further investigated experimentally, based on some specific properties of flexural wave propagation in tapered plates (wedges) of power-law profile that have to be partially covered by narrow thin strips of absorbing layers.

TL;DR: In this paper, the authors demonstrate the influence of stack parameters such as plate thickness (PT) and plate spacing (PS) with resonator length on the performance of a thermoacoustic engine, which are measured in terms of onset temperature difference, resonance frequency and pressure amplitude using air as a working fluid.

TL;DR: In this article, the first comprehensive study of shallow shell vibrations subjected to as many as 21 possible boundary conditions is presented, including spherical, cylindrical and hyperbolic paraboloidal shells.

TL;DR: In this paper, a series of thin, lightweight and low-cost sound absorption composites consisting of chlorinated polyethylene (CPE) and seven-hole hollow polyester fibers (SHPF) were fabricated.

TL;DR: In this article, the role of a resistive layer on a porous material is discussed and the guidelines for rational use of high resistive layers in order to maximize the normal sound absorption of porous multilayers are given.

TL;DR: Standards and recommended practices, designed for “Balanced approach” to aircraft noise management around airports, are presented and an overview of measures applied by airports worldwide in order to reduce noise in the surroundings is provided showing their frequency and variety.

TL;DR: In this article, the authors modeled the sound field in train compartments, treated as a series of connected air cavities, using statistical energy analysis, and used an adjusted SEA model to predict the rate of spatial decay within a cavity.

TL;DR: In this paper, the possibility of monitoring seeded defects on worm gears with acoustic emission was explored, and comparisons were made with vibration analysis, and it was shown that AE offers better diagnostic capability than vibration analysis.

TL;DR: In this article, the authors review the sound quality process and neural network models, and extend these introductions into a discussion regarding the value that can be gained in using an intelligent systems approach, namely ANNs, to sound quality analysis.

TL;DR: In this article, subjective sound quality (SQ) evaluations were obtained, simple and multiple regression models were generated, and these were used with the Semantic Differential Method (SDM) to determine what characteristics trigger a “pleasant” response from listeners.

TL;DR: In this paper, the free vibrations of cylindrical shells with elastic boundary conditions were investigated by the method of wave propagations, and the elastic support boundary conditions can be arbitrarily specified in terms of 8 independent sets of distributed springs.

TL;DR: In this article, the effects of coupling up two Helmholtz resonators on their overall sound absorption performance were investigated and the effect of compartmenting the cavity of a resonator on its sound absorption property was also discussed.

TL;DR: In this article, the authors used the scale law for the velocity dependence of the inflow broadband noise and airfoil self-noise in wind turbines and found that for the 1.5 MW WT, inflow turbulence noise was dominant over the whole frequency range.

TL;DR: In this paper, the authors present a system architecture of the first large (300 element circular array with a diameter of 2m) MEMS microphone array system for live sports broadcast.

TL;DR: In this paper, a series of measurements on four polyurethane foam samples with and without pore membranes were made using the ultrasonic slope method and it was found that the deduced value of tortuosity depends on the measurement temperature.

TL;DR: In this article, a nonlinear system identification model based on an adaptive Volterra filter is developed to investigate the inherent nonlinear phenomenon of a parametric acoustic array effect in air, which is the byproduct of nonlinear interaction between the primary waves.

TL;DR: In this article, four generalized cross-correlation methods for localization of speech sources with two microphones have been analyzed in different real scenarios with a stationary noise source, and these scenarios have been acoustically characterized, in order to relate the behavior of these cross correlation methods with the acoustic properties of noisy scenarios.

TL;DR: In this paper, the economic feasibility coefficient is defined and used as a final numerical value for comparing the overall efficiency of barrier design, and the optimization process is done by using a genetic algorithm.

TL;DR: In this paper, the authors examined two methods for calibrating recorders to measure sound levels and found that the results were stable over a 23-day deployment outdoors with wide variation in ambient temperature and humidity.

TL;DR: In this paper, the role of multi-layered viscoelastic parts, so called shims, to prevent squeal noises of automotive brake systems is discussed, and it is shown that shims are almost uniquely solicited in their normal direction in brake systems.

TL;DR: The three-segment approach procedure has been obtained as an optimized flight path which can substantially reduce noise levels and could benefit both airlines and communities.

TL;DR: In this article, a study leading to the establishment of the acoustic comfort index in motor cars is described, where five light to medium hatch cars of different makes have been tested for two different conditions: public roads, and restricted test roads.

TL;DR: In this paper, the authors present an experimental investigation in which several technologies such as Acoustic Emission, vibration and motor current signature analysis, were applied to identify the presence of a naturally fatigued pinion shaft in an operating gearbox.

TL;DR: In this article, the effects of the finite size of a sample on the measurement of the normal absorption coefficient are explored with the aid of a BEM model, which is referred to as the PU method.