Searched for:
(1 - 20 of 27)

Pages

document
van Neer, P.L.M.J. (author), Vos, H.J. (author), Volker, A.F.W. (author)
Proper spatial sampling is critical for high quality imaging. If the sampling criterion is not met, grating lobe artifacts appear in the image. In non-destructive testing applications efficiency is being increased by the steady enlargement of the field of view, resulting in more elements and thus a higher transducer complexity and cost. In the...
conference paper 2016
document
Volker, A.W.F. (author), van Zon, A.T. (author), Hsu, Z.C. (author), van den Boogert, L. (author)
Corrosion is one of the industries major issues regarding the integrity of assets. Currently inspections are conducted at regular intervals to ensure a sufficient integrity level of these assets. Cost reduction while maintaining a high level of reliability and safety of installations is a major challenge. There are many situations where the...
conference paper 2016
document
van Neer, P.L.M.J. (author), Volker, A.F.W. (author)
A proper spatial sampling is critical for high quality imaging. If the sampling criterion is not met, artifacts appear in the image, generally referred to as grating lobes. For inspection efficiency the width of the field of view is becoming larger leading to an increase in the number of elements and therefore transducer complexity and cost. The...
conference paper 2015
document
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
document
Vos, H.J. (author), van Neer, P.L.M.J. (author), Verweij, M.D. (author), de Jong, N. (author), Volker, A.W.F. (author)
Three-dimensional (3D) high resolution beamforming is made more difficult by high data rates. This can be overcome by two-step imaging approaches such as the synthetic aperture beamforming technique. In this technique the first step significantly reduces the data rate by line-based delay and sum, whereas the second stage recombines the data to a...
conference paper 2015
document
Volker, A.W.F. (author), van Zon, A.T. (author)
Corrosion is one of the industries major issues regarding the integrity of assets. Currently, inspections are conducted at regular intervals to ensure a sufficient integrity level of these assets. Cost reduction while maintaining a high level of reliability and safety of installations is a major challenge. There are many situations where the...
conference paper 2014
document
van Zon, A.T. (author), Volker, A.W.F. (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 had been developed to create a map of the wall thickness using the travel times of guided waves. It can be used for both monitoring and for...
conference paper 2014
document
Volker, A.W.F. (author), van Zon, A.T. (author)
The inspection of wall loss corrosion is difficult at pipe supports due to limited accessibility. 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 transmitted in the...
conference paper 2014
document
Volker, A.W.F. (author)
Phased arrays are often used for rapid inspections. Phased arrays can be used to synthesize different wave fronts. For imaging, focused wave fronts are frequently used. In order to build an image, the phased array has to be fired multiple times at the same location. Alternatively, different data acquisition configurations can be designed in...
conference paper 2014
document
van Neer, P.L.M.J. (author), Volker, A.W.F. (author), Pierre, G. (author), Bouvet, F. (author), Crozat, S. (author)
Nanoparticles are increasingly used in a number of applications, e.g. coatings or paints. To optimize nanoparticle production in-line quantitative measurements of their size distribution and concentration are needed. Ultrasound-based methods are especially suited for in-line particle sizing. These methods can be used for opaque dispersions and...
conference paper 2014
document
van Neer, P.L.M.J. (author), Rasidovic, A. (author), Volker, A.W.F. (author)
There has been considerable interest in the noninvasive manipulation of particles in dispersions during the last 15 years. The manipulation techniques based on acoustic radiation forces are particularly interesting as they allow for the manipulation of particles based on their density, compressibility and/or size. The majority of the acoustic...
conference paper 2013
document
van Neer, P.L.M.J. (author), Robers, T. (author), Volker, A.W.F. (author)
pMUTs are efficient ultrasound sources and receivers in gasses, and are cheap to produce due to their lithographic production process. Making use of their 1st resonance frequency, a good signal to noise ratio (SNR) may be obtained using limited power. This is of interest for low cost-low power gas flow meters. However, using pMUTs in this...
conference paper 2013
document
De Soares Silva e Melo Mota, M. (author), van Neer, P.L.M.J. (author), van der Heiden, M.S. (author), Volker, A.W.F. (author)
Scanning using a strongly focused transducer gives a narrow focus depth and locally a high resolution. To obtain a high resolution at every point along the acoustic axis imaging is applied. Because the focal point can be considered as a second source, the wavefield can be split in its causal and anticausal parts. Imaging can be performed...
conference paper 2013
document
Volker, A.W.F. (author), Hunter, A.J. (author)
Anisotropic materials are being used increasingly in high performance industrial applications, particularly in the aeronautical and nuclear industries. Some important examples of these materials are composites, single-crystal and heavy-grained metals. Ultrasonic array imaging in these materials requires exact knowledge of the anisotropic...
conference paper 2012
document
Volker, A.W.F. (author), Hunter, A.J. (author)
Anisotropic materials are being used increasingly in high performance industrial applications, particularly in the aeronautical and nuclear industries. Some important examples of these materials are composites, single-crystal and heavy-grained metals. Ultrasonic array imaging in these materials requires exact knowledge of the anisotropic...
conference paper 2012
document
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
document
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
document
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
document
Volker, A.W.F. (author), Vos, H.J. (author), Hunter, A. (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
document
van Capel, P.J.S. (author), van Vossen, R. (author), Volker, A.W.F. (author)
The application of phased arrays in NDT applications is growing. 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 2011
Searched for:
(1 - 20 of 27)

Pages