Showing papers in "Applied Acoustics in 2009"

TL;DR: In this paper, the sound absorption of industrial waste, developed during the processing of tea leaves, was investigated and three different layers of tea-leaf-fibre waste materials with and without backing provided by a single layer of woven textile cloth were tested for their sound absorption properties.

TL;DR: In this article, the authors provide an overview of recent developments in the application of multibeam echosounders for seafloor habitat studies, with a focus on the use of backscatter data for surficial geology and habitat mapping.

TL;DR: In this article, the authors analyzed the spatial characteristics of urban environmental noise by using noise maps produced at 345 noise monitoring stations in Tainan, Taiwan and found that the highest and lowest average noise levels were 696 dB and 593 dB(A) during summer mornings and winter evenings, respectively.

TL;DR: In this article, an approach to combine mosaicking and angular response analysis techniques in an attempt to take advantage of both the spatial resolution of the mosaic, and the angular resolution derived from the angular response was proposed.

TL;DR: In this paper, the authors present the condition monitoring of a lab-scale, single stage, gearbox using different non-destructive inspection methodologies and the processing of the acquired waveforms with advanced signal processing techniques.

TL;DR: In this article, the authors have studied the noise levels which the workers of the construction sector are exposed to and analyzed the most important levels and indexes with those data, and afterwards, they have been compared with the limits imposed by the different current regulations.

TL;DR: In this paper, an experimental test-rig was designed such that defects of varying sizes could be seeded onto the outer and inner races of a test bearing, and it was concluded that the geometric defect size of outer race defects can be determined from the acoustic emissions waveform.

TL;DR: In this article, a simple extended acoustical model on the basis of Biot-Allard model by using the idea of convective heat transfer in metallic tube for reference in order to calculate the sound absorption characteristics of porous sintered fiber metal.

TL;DR: In this article, an automated segmentation of multibeam images and data from an 80-km 2 survey were classified into regions of acoustic similarity based on a large number of features.

TL;DR: In this article, a seafloor classification method that employs the MBES backscatter data is presented. But the method is independent on the quality of MBES calibration, and its performance is insensitive to seafladoor type variation along the MBE swathe and corrections for the angular dependence of the backscattered are not needed.

TL;DR: In this paper, the authors present the results of an evaluation of acoustic comfort of classrooms built according to a standard design, based on measurements of reverberation time, sound pressure level inside and outside the classrooms, and sound insulation.

TL;DR: The Brandenburg University of Technology at Cottbus is a newly commissioned research facility for the experimental study of sound generation from bodies immersed in a fluid flow as mentioned in this paper, where the design criteria for the open jet wind tunnel that provides a maximum wind speed of 72m/s at continuous operation and may be operated with nozzles of different dimension between 35cm diameter (circular nozzle) and 12 cm by 14.7 cm (rectangular nozzle).

TL;DR: It is shown that beam tracing algorithms can still be optimized by utilizing the spatial coherence in path validation with a moving listener, and the acoustic reflection paths can be calculated even for a moving source in simple cases.

TL;DR: In this paper, a revised theory for a double-leaf microperforated panel space absorber (DLMPP) is presented: a Helmholtz integral formulation is employed to obtain a rigorous solution for more precise prediction of the absorptivity of a DLMPP.

TL;DR: In this article, the acquisition performance of both multibeam and sidescan sonar backscatter imagery is compared and examples shown and the logistical factors affecting the two systems during surveying are discussed and data from both systems compared.

TL;DR: In this article, a study was conducted in Hong Kong to understand mixed transportation noise-annoyance response, and the results showed that annoyance is largely determined by noise disturbance and perceived noisiness.

TL;DR: In this article, textural analyses of multibeam sonar imagery from Stanton Banks, on the continental shelf off Northern Ireland, were performed using K-means classifier.

TL;DR: In this article, a self-organising artificial neural network is used as a rapid classifier of grids of bathymetry and attributes such as slope and roughness, and backscatter strength and textures.

TL;DR: In this article, the authors present an experimental investigation that assesses the effectiveness of acoustic emission in identifying seeded defects on helical gears; also vibration analysis has performed to study the effect of seeded defect on the vibration signature of the meshing gears.

TL;DR: In this article, the authors present the design and performance of an open jet, blow down wind tunnel that was newly commissioned in the anechoic chamber at the ISVR, University of Southampton, UK.

TL;DR: In this article, the results of experimental measurements deriving from previous acoustical surveys are statistically analyzed in order to better understand the spatial variation of acoustic parameters leading to the definition of a set of guidelines to standardize the choice of sources and receivers locations.

TL;DR: A hybrid approach to developing a strategic noise map by integrating measurements taken on-site with predictions was developed and yielded a refined noise map that presented noise levels which were more reflective of the measured levels recorded on- site.

TL;DR: In this paper, a sound quality index which can objectively evaluate the booming sensation was derived, where subjective pitch was employed to find only aurally relevant tonal components which influence booming sensation as well as loudness.

TL;DR: In this paper, it was shown that the translational instability that gives rise to the reciprocal translation of a spherical bubble between the pressure antinode and the pressure node is caused by the hysteresis in the main resonance of the bubble.

TL;DR: In this article, it was shown that there is a discrete frequency tone within the audible noise spectra, which is in strong correlation with development of the cavitation process in the pump.

TL;DR: In this paper, the authors studied the low frequency vibrational behavior and radiated sound of a submarine hull under axial excitation, which is modelled as a fluid-loaded cylindrical shell with internal bulkheads and ring-stiffeners and closed at each end by circular plates.

TL;DR: In this article, a study of the effect of HVAC noise on vehicle acoustical comfort and overall quality perception of a vehicle is presented. But the study was divided into two steps: the first step aimed to identify the most significant attributes that contribute to the perception of similarity or dissimilarity of this kind of noise, using the paired comparison technique and correlation of the results with psychoacoustic models.

TL;DR: In this article, a non-iterative source location algorithm employing four acoustic emission (AE) sensors was proposed to reduce the error in AE signal arrival time calculation and compared with existing iterative methods.

TL;DR: In this article, access to quiet areas in cities is important to avoid adverse health effects due to road traffic noise, and most urban areas which are or can become quiet (L A,eq

TL;DR: In this article, modified scaled distances (SDs) based on empirical equations considering such factors as blasting parameters and geological parameters of rock mass for bench blasting in quarries were used to obtain an environmentally friendly and technically practicable results by using site specific SDs instead of conservative SD values.