Showing papers in "Applied Acoustics in 2003"

TL;DR: The cross analysis between survey data and acoustic parameters indicated the sound level is appropriate to the description of main thorough fares, but for similar sound level locations (square, market, or playground) two further perceptive factors were remind.

TL;DR: In this article, the authors compared three different methods used in calculation of transmission loss values: the traditional FEM, the 4-pole transfer matrix method and the 3-point method, and concluded that the FEM is better suited for this kind of application.

TL;DR: In this article, the authors used the wavelet transform to analyze the mode shape of a Timoshenko beam and demonstrated that the crack position can be detected by this method even though the crack is very small.

TL;DR: In this article, the authors compared 5 years of continuous noise measurements carried out at one of the most important squares in Valencia (Spain) to determine the appropriate measuring time in order to obtain a 24-h noise level suitable to represent the annual equivalent level.

TL;DR: In this paper, a fuzzy mathematic method is applied to calculate the probability of noise annoyance to evaluate the influence of the visibility of the source on an individual's degree of subjective noise annoyance.

TL;DR: In this paper, the authors investigated road traffic noise in Greater Cairo, the capital and the largest city in Egypt and the eleventh biggest city in the world, and found that there was a strong relationship between road traffic noises levels and the percentage of highly annoyed respondents.

TL;DR: In this article, an exact solution is obtained by solving the classical shell vibration equations and the acoustic wave equations simultaneously, and transmission losses obtained from the solution are compared to the transmission losses that are measured for a cylindrical shell of finite length and the same cross-sectional dimensions.

TL;DR: In this paper, the authors overview the physics of acoustic streaming, discus the various physical phenomena which generate the effect, and highlight the favorable scaling issues of acoustic stream that make it a viable alternative in micro-fluidic devices.

TL;DR: The 1998 Norwegian Socio-vibrational Survey with 1503 respondents from 14 study areas was undertaken in the autumns of 1997 and 1998 as discussed by the authors, and the response rate was 50%.

TL;DR: In this paper, a new classification of granular media has been proposed which is related to the characteristic particle dimension and the specific density of the grain base, which is a useful characteristic for rapid evaluation of the acoustic performance of loose granular mixes.

TL;DR: In this article, a new method of noise reduction assessment is proposed to estimate the A-weighted sound pressure level for a new road surface by measuring the noise generated by a few vehicles on an old surface with dense asphalt and on a new surface with porous asphalt.

TL;DR: In this article, the results of a wide acoustic environment survey were presented, where sound pressure measurements were carried out in a group of offices and the measurements lasted for five minutes and the resulting noise spectra were used to calculate the most significant acoustic parameters.

TL;DR: In this paper, an experimental investigation of an actively controlled double-glazed window with adaptive feedback control has been described, which has been tested in different configurations, i.e. fully and partially connected controllers.

TL;DR: In this article, an experimental investigation of an actively controlled double-glazed window with a feed-forward controller is presented, where different combinations of distributed loudspeakers and microphones were realized driving them in parallel by single channels of the controller.

TL;DR: In this paper, a revised model for computing the non- resonant coupling loss factor from a room to cavity is presented which gives much better agreement with measured data, allowing better predictions to be made of sound transmission through lightweight double walls.

TL;DR: In this paper, the authors focused on the ability of finite element models and analytical models to predict precisely the behavior of such a complicated structure, especially with its orthotropy and rib effects.

TL;DR: In this paper, a neural network model of polyurethane foams is proposed to predict multiple acoustical properties including the sound absorption coefficient and the surface impedance, which can be used to develop models for many different classes of materials with different sets of input and output parameters.

TL;DR: In this paper, an empirical method for determination of statistical maximum velocity, vw, 95, or alternatively acceleration, Vw,95, was introduced, which is obtained as the 95-percentile of maximum weighted vibration velocities (or acceleration) from a minimum number of representative road and rail traffic events.

TL;DR: In this paper, a pitch detection algorithm based on second generation wavelet transform was developed, which reduced the computational load of those algorithms that were based on classical wavelet transforms and was tested for both real speech and synthetic speech signal.

TL;DR: In this paper, an improved model to predict energy relations in churches is proposed, where a detailed acoustic survey was carried out of nine Romanesque churches having volumes ranging from 33 000 to 1500 m 3, and the measured sound level and early/late ratio showed significant correlation with the source-receiver distance.

TL;DR: In this paper, a geometrical ray theory is developed for the prediction of noise levels inside a balcony due to road traffic, and the insertion loss is defined as the difference in the noise levels with and without the presence of a balcony.

TL;DR: In this article, the performance of a T-shaped absorbing cap with road traffic noise conditions is investigated. But the authors focus on the road barrier diffracting caps and do not consider the impact of road traffic noises on their performance.

TL;DR: In this paper, the authors describe the design of a system for carrying out dynamic maximum length sequence (MLS) based measurements of road surface porosity and demonstrate that stable dynamic measurements can be carried out at speeds of up to 30 km/h.

TL;DR: A new equation for the computation of thesize of a receiver has been proposed and it has considered such factors as the size of the room, the number of initial rays and the distance from source to receiver.

TL;DR: In this paper, a new Nordtest Method, NT ACOU 106 Acoustics (Assessment of annoyance by vibrations in dwellings from road and rail traffic) has been defined, based on experiences with the 1998 Norwegian Socio-vibrational Survey and a Swedish socio-acoustic survey supplemented with vibration measures.

TL;DR: In this paper, the authors compared the noise levels before and after the opening of the A-3 motorway that goes through Motilla de Palancar, province of Cuenca, Spain.

TL;DR: In this article, the effect of the presence of a contoured duct and a lack thereof at the inlet of an axial flow fan is analyzed, and the results show the strong involvement of the upstream turbulence level in the generation of the noise, and in particular, of broadband noise.

TL;DR: In this paper, the influence of hearing protection devices (HPDs) on the understanding of speech in young adults with normal hearing, both in a silent situation and in the presence of ambient noise.

TL;DR: An algorithm for locating low altitude moving targets with acoustic methods based on a five-element planar acoustic sensor array is put forward, realized through estimations of the sensor-to-sensor time delays of the source signal generated by the low altitudemoving target.

TL;DR: In this article, a piezoelectric array of rectangular segments of PVDF film attached on the surface of the beam is taken as sensor, and the output signals of the PVDF films are multiplied by appropriate weights.