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Massaad, J. (author), van Neer, P.L.M.J. (author), van Willigen, D.M. (author), Sabbadini, A. (author), de Jong, N. (author), Pertijs, M.A.P. (author), Verweij, M.D. (author)
Current ultrasonic clamp-on flow meters consist of a pair of single-element transducers which are carefully positioned before use. This positioning process consists of manually finding the distance between the transducer elements, along the pipe axis, for which maximum SNR is achieved. This distance depends on the sound speed, thickness and...
article 2021
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Massaad, J. (author), van Neer, P.L.M.J. (author), van Willigen, D.M. (author), de Jong, N. (author), Pertijs, M.A.P. (author), Verweij, M.D. (author)
Acoustic wave propagation in ultrasonic flow measurements is typically assumed to be linear and reciprocal.However, if the transmitting transducer generates a sufficiently high pressure, nonlinear wave propagation effects become significant. In flow measurements, this would translate into more information to estimate the flow and therefore a...
article 2021
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Tajdari, F. (author), Berkhoff, A.P. (author), de Boer, A. (author)
This paper focuses on extensive numerical and experimental investigations of a thin sandwich acoustic source. Due to an energy inefficient actuation design, a thin sandwich acoustic source that was proposed in an early study is redesigned and reconstructed in the current research. The thin acoustic source in the present paper is actuated by long...
article 2020
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Tajdari, F. (author), Berkhoff, A.P. (author), van der Zee, R.A.R. (author), de Boer, A. (author)
article 2020
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Tajdari, F. (author), Berkhoff, A.P. (author), de Boer, A. (author)
This paper studies an acoustic source with a relatively small thickness and a high bending stiffness. The acoustic source operates in the low frequency, quasi-static regime. The focus of the current study is on the actuation part in order to design an appropriate excitation mechanism. A flexural mechanism is modeled in combination with a...
article 2020
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article 2019
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Tajdari, F. (author), Berkhoff, A.P. (author), de Boer, A. (author)
This paper studies an acoustic source with a relatively small thickness and high bending stiffness. Piezoelectric actuators are used to drive the moving component of the acoustic source. In the current study, a lumped model is used to represent the acoustic source that is excited by a piezoelectric stacked actuator. The equivalent electrical...
conference paper 2018
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Tajdari, F. (author), Berkhoff, A.P. (author), de Boer, A. (author)
This paper studies a lumped model of an acoustic source with a relatively small thickness and high bending stiffness. Voice coil and piezoelectric actuators are used to drive moving components of the acoustic source. Feedback and feedforward damping control techniques are used to actively obtain a smooth frequency response, especially at low...
conference paper 2017
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Berkhoff, A. (author), Tajdari, F. (author)
This paper presents a method to realize an acoustic source for low frequencies with relatively small thickness. A honeycomb plate structure which is open on one side combines the radiating surface and the major part of the air cavity. The vibration of the plate is controlled with a decentralized feedback controller. The fundamental resonance...
conference paper 2017
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Aarts, G. (author), von Benda-Beckmann, A.M. (author), Lucke, K. (author), Özkan Sertlek, H. (author), van Bemmelen, R. (author), Geelhoed, S.C.V. (author), Brasseur, S. (author), Scheidat, M. (author), Lam, F.P.A. (author), Slabbekoorn, H. (author), Kirkwood, R. (author)
Anthropogenic sound in the marine environment can have negative consequences for marine fauna. Since most sound sources are intermittent or continuous, estimating how many individuals are exposed over time remains challenging, as this depends on the animals’ mobility. Here we explored how animal movement influences how many, and how often,...
article 2016
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Tajdari, F. (author), Berkhoff, A.P. (author), de Boer, A. (author)
The present work describes the electrical, mechanical and acoustical behavior of a thin honey-comb structure as an acoustic source. The acoustic source has to operate in the low frequency, quasi-static regime and is driven by a piezoelectric stack actuator. In addition, a two-way energy flow between the actuator and a connected amplifier is...
conference paper 2016
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Kastelein, R.A. (author), Helder-Hoek, L. (author), Gransier, R. (author), Terhune, J.M. (author), Jennings, N. (author), de Jong, C.A.F. (author)
Acoustic mitigation devices (AMDs) are used to deter marine mammals from construction sites to prevent hearing injury by offshore pile-driving noise. In order to quantify the distance at which AMDs designed as ‘seal scarers’ are detected by seals, the 50% hearing thresholds for playbacks of their sounds were determined. The broadband hearing...
article 2015
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Verreault, J. (author)
The PELE ammunition is characterized by a low-density filling material surrounded by a high-density brittle jacket material. An analytical model describing the fragmentation of this ammunition behind a target plate is presented. This model assumes uniaxial strain in the filling and uses the RankingeHugoniot relations to calculate the material...
article 2015
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van Neer, P.L.M.J. (author), Rasmijn, L.N.R. (author), Franse, W.J.M. (author), Geers, L. (author), Rasidovic, A. (author), Volker, A.W.F. (author)
Lately, there has been significant interest in the noninvasive manipulation of particles and liquids. The reported acoustic methods rely on either the acoustic radiation force or acoustic streaming. The latter can be used in developed flows to induce fluid velocities angled to the liquid flow direction. These methods often use standing wave...
conference paper 2015
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Kastelein, R.A. (author), Hoek, L. (author), Gransier, R. (author), de Jong, C.A.F. (author), Terhune, J.M. (author), Jennings, N. (author)
Acoustic Mitigation Devices (AMDs) are used to deter marine mammals from construction sites, in order to prevent hearing injury by offshore pile driving noise. To estimate the distance at which two AMDs designed as ‘seal scarers’ (Ace Aquatec and Lofitech) are detected by harbor porpoises, the 50% hearing detection thresholds for playbacks of...
article 2015
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Nijhof, M.J.J. (author), Binnerts, B. (author), de Jong, C.A.F. (author), Ainslie, M.A. (author)
Modelling the sound levels in the water column due to pile driving operations nearby and out to large distances from the pile is crucial in assessing the likely impact on marine life. Standard numerical techniques for modelling the sound radiation from mechanical structures such as the finite element (FE) and boundary element method are not well...
conference paper 2014
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Dol, H.S. (author), Colin, M.E.G.D. (author), Ainslie, M.A. (author), van Walree, P.A. (author), Janmaat, J. (author)
Abstract—Sea-surface scattering by wind-generated waves and bubbles is regarded to be the main nonplatform related cause of the time variability of shallow acoustic communication channels. Simulations for predicting the quality of acoustic communication links in such channels thus require adequate modeling of these dynamic sea-surface effects....
article 2013
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van der Eerden, F.J.M. (author), Graafland, F. (author), Wessels, P.W. (author), Basten, T.G.H. (author)
A model based monitoring system is applied on a local scale in an urban area to obtain a better understanding of the traffic noise situation. The system consists of a scalable sensor network and an engineering model. A better understanding is needed to take appropriate and cost efficient measures, especially when changes to the local...
conference paper 2013
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Kastelein, R.A. (author), Steen, N. (author), Gransier, R. (author), de Jong, C.A.F. (author)
article 2013
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Xu, B. (author), Wind, J. (author), de Bree, H.E. (author), Basten, T.G.H. (author), Druyvesteyn, E. (author), TNO Industrie en Techniek (author)
An acoustic vector sensor array consists of multiple sound pressure microphones and particle velocity sensors. A pressure microphone usually has an omni-directional response, yet a particle velocity sensor is directional. Currently, acoustic vector sensor arrays are under investigation for far field source localization and visualization. One of...
conference paper 2010
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