Search results for "ACOUSTIC"

Physiological Measures Regress onto Acoustic and Perceptual Features of Soundscapes

2013

There is no exact model for the relationship between the autonomic nervous system (ANS) and evoked or perceived emotion. Music has long been a privileged field for exploration, while the contribution of soundscape research is more recent. It is known that health is influenced by the sonic environment, and the study here presented aimed to investigate the nature and strength of relationships between soundscape features and physiological responses linked to relaxation or stress. In a controlled experiment, seventeen healthy volun-teers moved freely inside a physical installation listening to soundscape recordings of nature, urban parks, eateries, and shops, reproduced using 3D ambisonic techn…

Error analysis and calibration for a novel pipe profiling tool

2020

Integrity of industrial pipework is ensured through routine inspection. Internal visual inspection tools are capable of characterising degradation in the form of corrosion, pitting, erosion and cracking. The accuracy of such inspection systems has a direct impact on decisions regarding the remaining lifetime of the asset. By minimising error margins, the asset may be operated with confidence for longer, with less uncertainty. This paper considers a probe system consisting of a laser profiler and camera that produces a textured 3D model of the internals of 2 – 6 inch pipework. The accuracy of the system is defined by the ability to extract laser projections from an image as it travels down t…

Effect of Enculturation on the Semantic and Acoustic Correlates of Polyphonic Timbre

2011

polyphonic timbre perception was investigated in a cross-cultural context wherein Indian and Western nonmusicians rated short Indian and Western popular music excerpts (1.5 s, n = 200) on eight bipolar scales. Intrinsic dimensionality estimation revealed a higher number of perceptual dimensions in the timbre space for music from one's own culture. Factor analyses of Indian and Western participants' ratings resulted in highly similar factor solutions. The acoustic features that predicted the perceptual dimensions were similar across the two participant groups. Furthermore, both the perceptual dimensions and their acoustic correlates matched closely with the results of a previous study perfor…

Acoustic, neural, and perceptual correlates of polyphonic timbre

2012

Power Line Communication in Medium Voltage Systems: Characterization of MV Cables

2008

The aim of this paper is to illustrate the development of a theoretical and experimental study on the characterization of medium voltage (MV) cables in the frequency range 25-200 kHz. Two transmission line configurations, line-ground and line-line, were considered in order to evaluate the main parameters, such as the characteristic impedance and the attenuation constant alpha. A simplified model of the line-ground configuration is proposed which allows one to evaluate the characteristic impedance and the attenuation constant by means of geometrical dimensions. The model was verified by experimental measurements on commonly used MV cables, RG7H1R, with an aluminium core of different sections…

Generalized wave propagation problems and discrete exterior calculus

2018

We introduce a general class of second-order boundary value problems unifying application areas such as acoustics, electromagnetism, elastodynamics, quantum mechanics, and so on, into a single framework. This also enables us to solve wave propagation problems very efficiently with a single software system. The solution method precisely follows the conservation laws in finite-dimensional systems, whereas the constitutive relations are imposed approximately. We employ discrete exterior calculus for the spatial discretization, use natural crystal structures for three-dimensional meshing, and derive a “discrete Hodge” adapted to harmonic wave. The numerical experiments indicate that the cumulat…

Modifications induced on rat exploratory behavior by acoustic stimulation: a multivariate analysis

2007

Acoustic wave guides as infinite-dimensional dynamical systems

2015

We prove the unique solvability, passivity/conservativity and some regularity results of two mathematical models for acoustic wave propagation in curved, variable diameter tubular structures of finite length. The first of the models is the generalised Webster's model that includes dissipation and curvature of the 1D waveguide. The second model is the scattering passive, boundary controlled wave equation on 3D waveguides. The two models are treated in an unified fashion so that the results on the wave equation reduce to the corresponding results of approximating Webster's model at the limit of vanishing waveguide intersection.

A methodology for the control of the residual lifetimes of carbon fibre reinforced composite pressure vessels

2005

International audience; Pressure vessels must be periodically proof tested. Traditional techniques for metal vessels are inapplicable for composite vessels as the latter do not break by crack propagation so that the reasoning behind the traditional testing procedures is not appropriate. Damage accumulation leading to the degradation of a composite vessel is by fibre failure. Fibres show a wide distribution in strengths and loading a composite inevitably breaks some. The method which has been developed is supported by an analysis of delayed fibre failure due to the relaxation of the resin around fibre breaks. This provokes overloading of intact fibres neighbouring breaks. The time until a cr…

Experimental Observation of a Large Low-Frequency Band Gap in a Polymer Waveguide

2018

The quest for large and low-frequency band gaps is one of the principal objectives pursued in a number of engineering applications, ranging from noise absorption to vibration control, and to seismic wave abatement. For this purpose, a plethora of complex architectures (including multiphase materials) and multiphysics approaches have been proposed in the past, often involving difficulties in their practical realization. To address the issue of proposing a material design that enables large band gaps using a simple configuration, in this study we propose an easy-to-manufacture design able to open large, low-frequency complete Lamb band gaps exploiting a suitable arrangement of masses and stif…