Searched for: subject%3A%22AS%255C%2B%255C-%255C%2BAcoustics%255C%2B%2526%255C%2BSonar%22
(261 - 280 of 342)
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Volker, A.W.F. (author), van Zon, A.T. (author)The concept of predictive maintenance using permanent sensors that monitor the integrity of an installation is an interesting addition to the current method of periodic inspections. Guided wave tomography has been developed to map the wall thickness using the travel times of guided waves. The method has been demonstrated for straight pipes. The...conference paper 2012
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Bolle, L.J. (author), de Jong, C.A.F. (author), Bierman, S.M. (author), van Beek, P.J.G. (author), van Keeken, O.A. (author), Wessels, P.W. (author), van Damme, C.J.G. (author), Winter, H.V. (author), de Haan, D. (author), Dekeling, R.P.A. (author)In view of the rapid extension of offshore wind farms, there is an urgent need to improve our knowledge on possible adverse effects of underwater sound generated by pile-driving. Mortality and injuries have been observed in fish exposed to loud impulse sounds, but knowledge on the sound levels at which (sub-)lethal effects occur is limited for...article 2012
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Volker, A.W.F. (author), van Capel, P. (author), van Vossen, R. (author)The application of phase arrays is growing for NDT applications. State of the art ultrasonic arrays consist of many small piezo-electric elements that can be excited separately to synthesize a desired wave front. This may vary from simple plane waves to complex-shaped focusing wave fields. An implicit requirement is that the source strength ...conference paper 2012
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Sivle, L.D. (author), Kvadsheim, P.H. (author), Fahlman, A. (author), Lam, F.P.A. (author), Tyack, P.L. (author), Miller, P.J.O. (author)Anthropogenic underwater sound in the environment might potentially affect the behavior of marine mammals enough to have an impact on their reproduction and survival. Diving behavior of four killer whales (Orcinus orca), seven long-finned pilot whales (Globicephala melas), and four sperm whales (Physeter macrocephalus) was studied during...article 2012
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Cure, C. (author), Antunes, R. (author), Samarra, F. (author), Alves, A.C. (author), Visser, F. (author), Kvadsheim, P.H. (author), Miller, P.J.O. (author)In cetaceans’ communities, interactions between individuals of different species are often observed in the wild. Yet, due to methodological and technical challenges very little is known about the mediation of these interactions and their effect on cetaceans’ behavior. Killer whales (Orcinus orca) are a highly vocal species and can be both food...article 2012
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Lepper, P.A. (author), Robinson, S.P. (author), Ainslie, M.A. (author), Theobald, P.D. (author), de Jong, C.A.F. (author)The installation of offshore wind farms in European waters and the scale of the planned activity have led to concern over the generation of noise and its potential impact on marine life. Much of this concern is centered around the noise generated by pile driving, which is used for the installation of the turbine foundations, and its potential...bookPart 2012
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Derksen, G.B. (author), de Roo, F. (author)The Dutch practice of assessment of the noise reducing properties of pavements according to the CPX (Close Proximity) Method has revealed that relatively large differences may occur between test results produced by different CPX operators. Due to these differences road authorities are facing questions and uncertainties about the acoustical...report 2012
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Derksen, G.B. (author), de Roo, F. (author)One of the methods to determine the influence of the road surfaces characteristics on the emission of noise by road traffic is the so-called Close Proximity (CPX) method, which measures the noise emission of the tyre-road contact in the near field of a sound radiating tyre. These measurements are executed with CPX measurement trailers....report 2012
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Volker, A.W.F. (author), Vos, H.J. (author), Hunter, A.J. (author), Lorenz, M. (author)The inspection of wall loss corrosion is difficult at pipe support locations due to limited accessibility. However, the recently developed ultrasonic Multi-Skip screening technique is suitable for this problem. The method employs ultrasonic transducers in a pitch-catch geometry positioned on opposite sides of the pipe support. Shear waves are...conference paper 2012
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Lam, F.P.A. (author)Walvissen ‘kijken’ onder water met hun oren, maar er zijn steeds meer geluidsbronnen op zee. Hoe komen we er achter wanneer walvissen last krijgen van het onderwatergeluid dat door de mens wordt gemaakt? Een van deze geluidsbronnen is sonar van de marine voor het opsporen van onderzeeboten. TNO onderzoekt de mogelijke (gedrags)effecten op...article 2012
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Derksen, G.B. (author), de Roo, F. (author)In de Nederlandse praktijk van het meten van de geluidsreductie van wegdekken met behulp van de CPX-methode [1] is gebleken dat er tussen de resultaten van verschillende uitvoerders van deze methode relatief grote verschillen bestaan die voor opdrachtgevers leiden tot vragen en onduidelijkheden over de akoestische kwaliteit van de gemeten...report 2012
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Clairbois, J.P. (author), de Roo, F. (author), Garai, M. (author), Conter, M. (author), Defrance, J. (author), Oltean-Dumbrava, C.A. (author), Durso, C. (author)The aim of this guidebook is to become a reference tool for noise mitigation through a better use of Noise Reducing Devices (NRD) (e.g.: Noise Barriers or sound Absorptive Claddings). It targets all the stakeholders involved in NRD projects (designers, manufacturers, authorities, construction companies, maintenance companies...) and who are...report 2012
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Nederlandse Organisatie voor Toegepast-Natuurwetenschappelijk Onderzoek (author), de Roo, F. (author), Lutgendorf, D. (author), Wessels, P.W. (author)Sound reflectivity is one of the intrinsic acoustical characteristics of noise reducing devices (NRD’s). It describes which percentage of an incident sound field is reflected back towards the opposite side of the road. The reflectivity is determined by the absorption properties of the material of the NRD as well as by the geometrical shape of...report 2012
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Nederlandse Organisatie voor Toegepast-Natuurwetenschappelijk Onderzoek (author), Lutgendorf, D. (author), de Roo, F. (author), Wessels, P.W. (author)Sound reflectivity is one of the intrinsic acoustical characteristics of noise barriers. It describes which percentage of an incident sound field is reflected back towards the opposite side of the road. The reflectivity is determined by the absorption properties of the material of the barrier as well as by the geometrical shape of the barrier,...report 2012
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Volker, A.W.F. (author), Vos, H.J. (author), Hunter, A.J. (author)The inspection of wall loss corrosion is difficult at pipe support locations due to limited accessibility. However, the recently developed ultrasonic Multi-Skip screening technique is suitable for this problem. The method employs ultrasonic transducers in a pitch-catch geometry positioned on opposite sides of the pipe support. Shear waves are...conference paper 2012
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van Vossen, R. (author), Colin, M. (author), Benders, F. (author), Ainslie, M.A. (author), Eidem, E.J. (author), Chalindar, B. (author), Juhel, B. (author), Dybedal, J. (author), Olsen, G.K. (author), Ivansson, S. (author), Abrahamsson, L. (author)Accurate environmental information is required for obtaining reliable predictions for the performance of low-frequency active sonar (LFAS) systems. This environmental information is, however, often unreliable or unavailable. For example, the acoustic seabed parameters relevant for the scattering and reflection of sound at the seabed are commonly...conference paper 2011
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Kastelein, R.A. (author), Steen, N. (author), de Jong, C.A.F. (author), Wensveen, P.J. (author), Verboom, W.C. (author)Naval sonar systems produce signals which may affect the behavior of harbor porpoises, though their effect may be reduced by ambient noise. To show how natural ambient noise influences the effect of sonar sweeps on porpoises, a porpoise in a pool was exposed to 1-s duration up-sweeps, similar in frequency range (6-7 kHz) to those of existing...article 2011
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van Beek, P.J.G. (author), de Roo, F. (author), Dittrich, M.G. (author)In the EU Green Paper on Future Noise Policy of 1996 it was already concluded that the total effect of EU and Member States legislation on environmental road traffic noise was unsatisfactory until then. This was underpinned by extensive studies in the late nineties in the Netherlands, Germany and other countries. A very recent study in the...conference paper 2011
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- Schutte, J.H. (author) doctoral thesis 2011
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Berkhoff, A.P. (author), Wesselink, J.M. (author)Model errors in multiple-input multiple-output adaptive controllers for reduction of broadband noise and vibrations may lead to unstable systems or increased error signals. In this paper, a combination of high-authority control (HAC) and low-authority control (LAC) is considered for improved performance in case of such model errors. A digital...article 2011
Searched for: subject%3A%22AS%255C%2B%255C-%255C%2BAcoustics%255C%2B%2526%255C%2BSonar%22
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