The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Lionel Haumesser - One of the best experts on this subject based on the ideXlab platform.
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Reduced propagation path for B/A Nonlinear Parameter evaluation
2019 International Congress on Ultrasonics, 2019Co-Authors: Lionel Haumesser, François Vander MeulenAbstract:The Nonlinear Parameter B/A expresses the quadratic distortion of an acoustic wave as it propagates. For fairly collimated beam, it depends linearly on the propagation distance. The longer the travel path, the better the ratio evaluation. However, in an industrial context, a moderate amount of fluid can be required to fill the measurement cell. Pulse echo methods have been shown to be good candidates for saving propagation length, taking advantage of back and forth travel paths between the emitter/receiver transducer and a reflector. However, strategies are still needed to further reduce propagation distance in order to limit the use of the product under test and handling time due to filling and emptying of the tank for the control of successive samples. We propose to take advantage of the extended acoustic signature obtained from the pulse echo method, taking into account several back wall echoes from the reflector. We show that processing of the first few non overlapped echoes leads to enhance the distortion ratio. In that way, usual values of distortion can be reached using a standard device for the measurement. The results show reliable evaluation of the Nonlinear Parameter in water when using several echoes.
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Ultrasonic Nonlinear Parameter measurement: critical investigation of the instrumentation
2011Co-Authors: Lionel Haumesser, J. Fortineau, Denis Parenthoine, T. Goursolle, F. Vander MeulenAbstract:Identification methods of Nonlinear Parameters are developed to characterize solid materials and soft tissues. In the frame of classical parametric interaction methods, the Parameter evaluation is based on the measurement of quantities combinations and/or multiple harmonic of primary wave frequencies, and are generally weak in comparison to the amplitudes of the sources. Hence, the use of experimental devices excited at high amplitude levels is required. One problem in the identification of Nonlinear Parameters is that the ultrasonic device itself is not exempt of Nonlinearity. Generally speaking the problem is to ensure, for each specific configuration, that the involved instrumentation (waveform generator, voltage amplifier, transducer), the coupling medium, mutual interactions between many sources..., do not perturb the evaluation of the investigated Nonlinear effects.
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Evaluation of B∕A Nonlinear Parameter using an acoustic self-calibrated pulse-echo method
Applied Physics Letters, 2008Co-Authors: F. Vander Meulen, Lionel HaumesserAbstract:The objective of this work is to develop an easy-to-build and robust setup for measuring the Nonlinearity Parameter B∕A in fluids using ultrasound. The method is based on the pulse-echo technique, using a single element broadband acoustic transducer, and requires electrical signal measurements. Results obtained in water and denatured alcohol validate the proposed procedure. The choice of a suitable primary wave frequency is discussed with regard to the transducer sensitivity. Further, the influence of the perturbations introduced by the experimental device Nonlinearities, and the role of the reflector on the measured second harmonic field amplitude are investigated.
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Contact phase modulation method for acoustic Nonlinear Parameter measurement in solid.
Ultrasonics, 2004Co-Authors: Maria Cristina Vila, Lionel Haumesser, F. Vander Meulen, S. Dos Santos, O. Bou MatarAbstract:In this work, a new method to measure in contact the Nonlinearity Parameter β of solid plates is presented. A high frequency (HF) tone-burst signal of 20 MHz is inserted in the material by a contact-transducer (with a suitable coupling). A low frequency (LF) pulse (2.5 MHz) is applied to the other face, in the opposite direction, so that the Nonlinear interaction of the two waves takes place during the back propagation toward the HF transducer. This collinear interaction creates a phase modulation of the HF tone-burst which is proportional to the β coefficient and the particle velocity of the LF wave. To determine this particle velocity, in time domain, an extended self-reciprocity calibration of the contact LF transducer is used. A numeric phase demodulation is then performed, giving the β coefficient of the sample. The proposed method is validated by Nonlinearity Parameter measurements in Fused Silica. The Nonlinear Parameter of Fused Silica measured is found to be in good agreement with the literature, and specially the negative sign of this Parameter.
F. Vander Meulen - One of the best experts on this subject based on the ideXlab platform.
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Ultrasonic Nonlinear Parameter measurement: critical investigation of the instrumentation
2011Co-Authors: Lionel Haumesser, J. Fortineau, Denis Parenthoine, T. Goursolle, F. Vander MeulenAbstract:Identification methods of Nonlinear Parameters are developed to characterize solid materials and soft tissues. In the frame of classical parametric interaction methods, the Parameter evaluation is based on the measurement of quantities combinations and/or multiple harmonic of primary wave frequencies, and are generally weak in comparison to the amplitudes of the sources. Hence, the use of experimental devices excited at high amplitude levels is required. One problem in the identification of Nonlinear Parameters is that the ultrasonic device itself is not exempt of Nonlinearity. Generally speaking the problem is to ensure, for each specific configuration, that the involved instrumentation (waveform generator, voltage amplifier, transducer), the coupling medium, mutual interactions between many sources..., do not perturb the evaluation of the investigated Nonlinear effects.
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Evaluation of B∕A Nonlinear Parameter using an acoustic self-calibrated pulse-echo method
Applied Physics Letters, 2008Co-Authors: F. Vander Meulen, Lionel HaumesserAbstract:The objective of this work is to develop an easy-to-build and robust setup for measuring the Nonlinearity Parameter B∕A in fluids using ultrasound. The method is based on the pulse-echo technique, using a single element broadband acoustic transducer, and requires electrical signal measurements. Results obtained in water and denatured alcohol validate the proposed procedure. The choice of a suitable primary wave frequency is discussed with regard to the transducer sensitivity. Further, the influence of the perturbations introduced by the experimental device Nonlinearities, and the role of the reflector on the measured second harmonic field amplitude are investigated.
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Contact phase modulation method for acoustic Nonlinear Parameter measurement in solid.
Ultrasonics, 2004Co-Authors: Maria Cristina Vila, Lionel Haumesser, F. Vander Meulen, S. Dos Santos, O. Bou MatarAbstract:In this work, a new method to measure in contact the Nonlinearity Parameter β of solid plates is presented. A high frequency (HF) tone-burst signal of 20 MHz is inserted in the material by a contact-transducer (with a suitable coupling). A low frequency (LF) pulse (2.5 MHz) is applied to the other face, in the opposite direction, so that the Nonlinear interaction of the two waves takes place during the back propagation toward the HF transducer. This collinear interaction creates a phase modulation of the HF tone-burst which is proportional to the β coefficient and the particle velocity of the LF wave. To determine this particle velocity, in time domain, an extended self-reciprocity calibration of the contact LF transducer is used. A numeric phase demodulation is then performed, giving the β coefficient of the sample. The proposed method is validated by Nonlinearity Parameter measurements in Fused Silica. The Nonlinear Parameter of Fused Silica measured is found to be in good agreement with the literature, and specially the negative sign of this Parameter.
Wilfrid Perruquetti - One of the best experts on this subject based on the ideXlab platform.
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Adaptive Estimation for Uncertain Nonlinear Systems: A Sliding-Mode Observer Approach
2018Co-Authors: Robert Franco, Hector Ríos, Denis Efimov, Wilfrid PerruquettiAbstract:This paper deals with the problem of adaptive estimation, i.e. the simultaneous estimation of the state and Parameters, for a class of uncertain Nonlinear systems. A Nonlinear adaptive sliding-mode observer is proposed based on a Nonlinear Parameter estimation algorithm. The Nonlinear Parameter estimation algorithm provides a rate of convergence faster than exponential while the sliding-mode observer ensures ultimate boundness for the state estimation error attenuating the effects of the external disturbances. Linear matrix inequalities (LMIs) are provided for the synthesis of the adaptive observer and some simulation results show the feasibility of the proposed approach.
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A Discontinuous Adaptive Sliding-Mode Observer for a Class of Uncertain Nonlinear Systems ⋆
2017Co-Authors: Hector Ríos, Denis Efimov, Wilfrid PerruquettiAbstract:In this paper the problem of simultaneous state and Parameter estimation is studied for a class of uncertain Nonlinear systems. A discontinuous adaptive sliding-mode observer is proposed based on a discontinuous Nonlinear Parameter estimation algorithm. It is shown that such an algorithm provides a rate of convergence faster than exponential. Then, the proposed discontinuous Parameter estimation algorithm is included in the structure of a sliding-mode state observer providing an ultimate bound for the full estimation error. Some simulation results illustrate the feasibility of the proposed adaptive sliding-mode observer.
Kyung-young Jhang - One of the best experts on this subject based on the ideXlab platform.
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Comparison of ultrasonic Nonlinear Parameters measured by PZT and LiNbO3 transducers
2016Co-Authors: Jongbeom Kim, Kyoung-jun Lee, Kyung-young JhangAbstract:The ultrasonic Nonlinear techniques have been known as effective methods to evaluate a microstructure change of material. The ultrasonic Nonlinear characteristic can be evaluated by the second-order ultrasonic Nonlinear Parameter β determined from the amplitudes of fundamental and second harmonic frequency components. The ultrasonic Nonlinear Parameter is generally measured by using a contact transducer; PZT and LiNbO3 transducers are commonly used. However, the measurement result may be dependent on the equipment. Here in, we are curious about whether the Nonlinear Parameters measured by different transducers are identical. Therefore, in this study, we compare the ultrasonic Nonlinear Parameters measured by different transducers, PZT and LiNbO3. For the experiment, the Al6061 specimens heat treated at 220°C with different aging time 60, 600, and 6000 min were prepared, and then the ultrasonic Nonlinear Parameter was measured by using two different kinds of transducer, PZT and LiNbO3. The results showed t...
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Relative measurement of acoustic Nonlinear Parameters and comparison of sensitivity to thermal aging
2015Co-Authors: Hogeon Seo, Gang Ren, Jongbeom Kim, Kyung-young JhangAbstract:The acoustic Nonlinearity measurement of ultrasonic waves are being extensively researched as a promising nondestructive evaluation element. In the condition of constant propagation distance and wave number, many researchers have measured the second-order relative acoustic Nonlinear Parameter, β′, that can be simply defined as the ratio of the amplitude of the second harmonic frequency component to the amplitude squared of the fundamental frequency component and compared them in order to identify the acoustic Nonlinearity variation according to material degradation. In this study, we extended this concept to the third-order relative acoustic Nonlinear Parameter, γ′, by defining it as the ratio of the amplitude of the third harmonic frequency component to the amplitude cubed of the fundamental frequency component. To investigate its effectiveness as a nondestructive evaluation element for the material property degradation, both the second-order acoustic relative Nonlinear Parameter and the third-order rela...
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development of pressure control system of contact transducer for measurement of ultrasonic Nonlinear Parameter
Journal of the Korean Society for Nondestructive Testing, 2007Co-Authors: Inho Lee, Daesoo Son, Ikhwang Choi, Taehun Lee, Kyung-young JhangAbstract:Ultrasonic Nonlinearity has been considered as a promising method to evaluate the micro damage of material; however, its magnitude is so small that its measurement is not easy. Especially, when we use contact PZT transducer, if the contacting pressure is not kept in constant during the measurement then there exists extraneous fluctuation in the measured Nonlinearity caused by the unstable contact condition, In this paper, we developed a pneumatic control system to keep the contacting pressure of transducer in constant during the measurement and analyzed the effect of contacting pressure to the ultrasonic Nonlinearity measurement As a result, we found that the pressure of transducer in our measurement system should be greater than 170 kPa to measure the ultrasonic Nonlinear Parameter in stable with no dependency on the contacting pressure.
Yeshaiahu Fainma - One of the best experts on this subject based on the ideXlab platform.
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group velocity dispersion and self phase modulation in silicon nitride waveguides
Applied Physics Letters, 2010Co-Authors: Kazuhiro Ikeda, Yeshaiahu FainmaAbstract:The group velocity dispersion (GVD) of silicon nitride waveguides, prepared using plasma enhanced chemical vapor deposition, is studied and characterized experimentally in support of Nonlinear optics applications. We show that the dispersion may be engineered by varying the geometry of the waveguide and demonstrate measured anomalous GVD values as high as −0.57 ps2/m and normal GVD values as high as 0.86 ps2/m. We also experimentally demonstrate the absence of any observed Nonlinear loss at the telecommunications wavelength at peak intensities of up to 12 GW/cm2. Spectral broadening due to self phase modulation in silicon nitride waveguides with a Nonlinear Parameter of 1.4 W−1/m is also demonstrated.
