N. Wilkie-Chancellier - Academia.edu (original) (raw)
Papers by N. Wilkie-Chancellier
Instrumentation Mesure Métrologie, 2012
2009 IEEE International Ultrasonics Symposium, 2009
... Bart Sarens, Christ Glorieux Laboratory of Acoustics and Thermal Physics Department of Physic... more ... Bart Sarens, Christ Glorieux Laboratory of Acoustics and Thermal Physics Department of Physics and Astronomy Heverlee, Belgium ... E-FIR filters are tested on experimental space-time signals corresponding to the propagation of Lamb waves generated by a pulse and observed ...
The Journal of the Acoustical Society of America, 2008
ABSTRACT Acoustic sensors often have a plane geometry due to manufacturing constrains. In the pre... more ABSTRACT Acoustic sensors often have a plane geometry due to manufacturing constrains. In the present work, the cylindrical geometry is investigated with a normal incident beam in order to suppress the edge effects on mode conversion. The experimental setup uses an aluminium cylindrical shell. A classical immersion transducer (2 MHz central frequency) sends a plane pulse wave on the shell at normal incidence. A second immersion transducer can turn around, enabling the observation of the waves scattered by the cylindrical shell. Previous works have shown that the acoustic field scattered by the shell as a rainbow structure enabling the acoustic spectrometry of the material poured inside the shell. From these results, the present study proposes an acoustical model linking the resonances parameters to the material ones, enabling the monitoring of time varying viscous materials. Several gelation monitoring experiments are performed and analysed using the proposed model. Results are in good agreement with quartz sensor measurements and offer a good alternative to wide frequency range measurements.
The Journal of the Acoustical Society of America, 2008
ABSTRACT
The Journal of the Acoustical Society of America, 2008
Journal of Physics: Conference Series, 2012
ABSTRACT Acoustic surface waves are widely used to sense and map the properties of the propagatio... more ABSTRACT Acoustic surface waves are widely used to sense and map the properties of the propagation media. In order to characterise local space-time waves, methods such as Gabor analysis are powerful. Nevertheless, knowing which wave is observed, extracting its full bandwidth contribution from the others and to map it in the signal domain is also of great interest. In the Fourier domain, the acoustic energy of a wave is concentrated along the wave-number frequency (k-ω) dispersion curve, a way to extract one wave from others is to filter the signals by mean of k-ω band-pass area that keeps only the selected surface wave. The objective of the present paper is to propose 2D Finite Impulse Response (FIR) filters based on an arbitrary area shape designed to extract selected waves. FIR filtering is based on convolving the impulse response of the filter with the signals. Impulse responses derived from using k-ω elliptical areas (E-FIR) are presented. The E-FIR filters are successfully tested on three experimental space-time signals corresponding to the propagation of Lamb waves measured by standard transducers on a cylindrical shell, by laser Doppler on a plate and generated by a circular pulse and observed by shearography on a rectangular plate.
Journal of Physics: Conference Series, 2009
Laser ultrasonics allow the observation of transient surface waves along their propagation media ... more Laser ultrasonics allow the observation of transient surface waves along their propagation media and their interaction with encountered objects like cracks, holes, borders. In order to characterize and localize these transient aspects in the Space-Time-Wave number-Frequency domains, the 1D, 2D and 3D Gabor transforms are presented. The Gabor transform enables the identification of several properties of the local wavefronts such as their shape, wavelength, frequency, attenuation, group velocity and the full conversion sequence along propagation. The ability of local properties identification by Gabor transform is illustrated by two experimental studies: Lamb waves generated by an annular source on a circular quartz and Lamb wave interaction with a fluid droplet. In both cases, results obtained with Gabor transform enable ones to identify the observed local waves.
IEEE Sensors Journal, 2000
This paper is a study of a new sensor for fluid characterization. This sensor is composed of a st... more This paper is a study of a new sensor for fluid characterization. This sensor is composed of a stainless steel plate in contact with a viscous material. The aim is to characterize the material viscosity by using reflected Lamb waves at the boundary interface. In order to identify the effects on the Lamb reflected modes by the viscous material, a complete study of the propagation wave in the alone plate is first presented. The propagation modes of the loaded plate are then investigated. By monitoring the mechanical impedance, the viscosity of the material in contact is extracted. In order to validate the experimental set-up, the mechanical impedance variation is measured for different water-glycerol mixtures. Results are in good agreement with those obtained by other techniques in the literature.
Spectrochimica Acta Part B: Atomic Spectroscopy, 2015
Spectrochimica Acta Part B Atomic Spectroscopy
The aim of this paper is to identify the different periods of construction or restoration of the ... more The aim of this paper is to identify the different periods of construction or restoration of the lead roof of a historic monument. Trace elements in a lead matrix can be a signature of the metallurgical processes, allowing identification of a specific time period for the production of the lead used to build the roof. The ability of LIBS (Laser Induced Breakdown Spectroscopy) to detect such trace elements in a lead matrix is therefore explored and checked by comparing its results with LA-ICP-MS as a reference method (Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry). Concentrations of 263 samples were compared between LIBS and LA-ICP-MS data and their correlation was evaluated. Another way to compare their results is also suggested by combining PCA (Principal Component Analysis) and GIS (Geographic Information System). As a result statistical mappings were created, highlighting metallurgical groups of samples across the roof of the building. This innovative approach links ...
Spectrochimica Acta Part B: Atomic Spectroscopy, 2015
ABSTRACT The aim of this paper is to identify the different periods of construction or restoratio... more ABSTRACT The aim of this paper is to identify the different periods of construction or restoration of the lead roof of a historic monument. Trace elements in a lead matrix can be a signature of the metallurgical processes, allowing identification of a specific time period for the production of the lead used to build the roof. The ability of LIBS (Laser Induced Breakdown Spectroscopy) to detect such trace elements in a lead matrix is therefore explored and checked by comparing its results with LA-ICP-MS as a reference method (Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry). Concentrations of 263 samples were compared between LIBS and LA-ICP-MS data and their correlation was evaluated. Another way to compare their results is also suggested by combining PCA (Principal Component Analysis) and GIS (Geographic Information System). As a result statistical mappings were created, highlighting metallurgical groups of samples across the roof of the building. This innovative approach links concentration and spatial location resulting in an easily interpretable graphical presentation of the data.
Ultrasonics, 2006
This paper deals with a study of the conversion of a Lamb wave at the loaded edge of a plate. An ... more This paper deals with a study of the conversion of a Lamb wave at the loaded edge of a plate. An experimental study is performed to know the interaction of surface waves with a viscoelastic material. A Lamb wave is generated by a wedge. At the end of the plate, this wave gives rise to several reflected waves. A first study makes it possible qualitatively to know the Lamb modes present in reflection. Secondly, conversion phenomena are studied to know if surface waves are sensitive to evolution in the time of the viscoelastic material structure. The selected material is a sol-gel containing silica.
2011 IEEE International Ultrasonics Symposium, 2011
ABSTRACT The optimization of new soft hybrid materials elaborated from liquid phase needs an “on ... more ABSTRACT The optimization of new soft hybrid materials elaborated from liquid phase needs an “on line” monitoring during the first steps of their formation. Up to date, few ultrasonic techniques ensure a complete tracking of the material characteristics. They often require a wired excitation particularly unsuited for hidden areas monitoring. This work presents an innovative magneto-ultrasonic sensor remotely controlled by an RF induction (at 100 MHz) in order to extract rheological properties of hidden complex fluids. An equivalent electrical model of the interactions between the developed wireless sensor and the complex fluid in contact is also presented. The validation study of this model using well-known viscous fluids (water-glycerol mixtures) is furthermore achieved.
Ultrasonics, 2006
Laser ultrasonic detection is a versatile and highly sensitive tool for the observation of surfac... more Laser ultrasonic detection is a versatile and highly sensitive tool for the observation of surface waves. In the following study, laser ultrasonic detection is used for the experimental study of spurious normal vibration modes of a disk quartz sensor excited by a voltage pulse. The AT cut crystal (cut of the crystal relative to the the main crystallographic axis is 35.25 degrees) is optimal for generating mainly thickness-shear vibrations (central frequency 6 MHz) on the quartz surface. However, resulting from shear-to-longitudinal and shear-to-surface mode conversion, and from the weak coupling with the other crystallographic axes, other modes (thickness-compressional and bending modes) are always present in the plate response. Since the laser vibrometer is sensitive to normal displacements, the laser investigation shows waves that can be considered as unwanted for the AT quartz used as a shear sensor. The scanned three dimensional (3D) amplitude-space-time signals are carefully analysed using their representation in three dual Fourier domains (space-time, wave number-frequency). Results on the transient analysis of the waves, the normal bending modes and the dispersion curves are shown.
2011 IEEE International Ultrasonics Symposium, 2011
ABSTRACT Bacterial adhesion and proliferation through biofilm is a major concern in industrial ap... more ABSTRACT Bacterial adhesion and proliferation through biofilm is a major concern in industrial applications where surfaces are in contact with aqueous fluids. Bacteria in these environments are capable of rapid attachment and community development on those surfaces. NDT can play an important role thanks to its capability to monitor bio-physical properties. In this study, a simple technique to monitor the rheological properties of S. Cerevisiae growth at microscopic scale is proposed. This technique uses shear waves generated by an AT-cut quartz crystal at 5 MHz. In order to optimize growing conditions, the temperature, pH and substrate on which the yeast grows are tightly controlled. This grow is performed under aerobic conditions. Using a suitable model including the electrical properties evolution during S. Cerevisiae cultivation, the rheological properties elastic and viscous moduli (respectively G' and G") can be accurately extracted. Thanks to the high sensitivity of the proposed technique, the ultradian mechanical oscillation of the entire yeast culture is observed. This preliminary micro-rheological monitoring study makes possible the online optimization of bioethanol production.
2010 IEEE International Ultrasonics Symposium, 2010
Abstract The sol-gel process is currently used to develop new materials with a wide range of appl... more Abstract The sol-gel process is currently used to develop new materials with a wide range of applications in chemical and food industries. An ultrasonic self-calibrated method is used to evaluate the behavior of the nonlinear coefficient during the sol to gel reaction. The ...
Ultrasonics, 2012
In many industrial processes where online control is necessary such as in the food industry, the ... more In many industrial processes where online control is necessary such as in the food industry, the real time monitoring of visco-elastic properties is essential to ensure the quantity of production. Acoustic methods have shown that reliable properties could be obtained from measurements of velocity and attenuation. This paper proposes a simple, real time ultrasound method for monitoring linear medium properties (phase velocity and attenuation) that vary in time. The method is based on a pulse echo measurement and is self-calibrated. Results on a silica gel are reported and the importance of taking into account the changes of the mechanical loading on the front face of the transducer will be shown. This is done through a modification of the emission and reception transfer parameters. The simultaneous measurement of the input and output currents and voltages enables these parameters to be calculated during the reaction. The variations of the transfer parameters are in the order of 6% and predominate other effects. The evolution of the ultrasonic longitudinal wave phase velocity and attenuation as a function of time allows the characteristic times of the chemical reaction to be determined. The results are well correlated with the gelation time measured by rheological method at low frequency.
Instrumentation Mesure Métrologie, 2012
2009 IEEE International Ultrasonics Symposium, 2009
... Bart Sarens, Christ Glorieux Laboratory of Acoustics and Thermal Physics Department of Physic... more ... Bart Sarens, Christ Glorieux Laboratory of Acoustics and Thermal Physics Department of Physics and Astronomy Heverlee, Belgium ... E-FIR filters are tested on experimental space-time signals corresponding to the propagation of Lamb waves generated by a pulse and observed ...
The Journal of the Acoustical Society of America, 2008
ABSTRACT Acoustic sensors often have a plane geometry due to manufacturing constrains. In the pre... more ABSTRACT Acoustic sensors often have a plane geometry due to manufacturing constrains. In the present work, the cylindrical geometry is investigated with a normal incident beam in order to suppress the edge effects on mode conversion. The experimental setup uses an aluminium cylindrical shell. A classical immersion transducer (2 MHz central frequency) sends a plane pulse wave on the shell at normal incidence. A second immersion transducer can turn around, enabling the observation of the waves scattered by the cylindrical shell. Previous works have shown that the acoustic field scattered by the shell as a rainbow structure enabling the acoustic spectrometry of the material poured inside the shell. From these results, the present study proposes an acoustical model linking the resonances parameters to the material ones, enabling the monitoring of time varying viscous materials. Several gelation monitoring experiments are performed and analysed using the proposed model. Results are in good agreement with quartz sensor measurements and offer a good alternative to wide frequency range measurements.
The Journal of the Acoustical Society of America, 2008
ABSTRACT
The Journal of the Acoustical Society of America, 2008
Journal of Physics: Conference Series, 2012
ABSTRACT Acoustic surface waves are widely used to sense and map the properties of the propagatio... more ABSTRACT Acoustic surface waves are widely used to sense and map the properties of the propagation media. In order to characterise local space-time waves, methods such as Gabor analysis are powerful. Nevertheless, knowing which wave is observed, extracting its full bandwidth contribution from the others and to map it in the signal domain is also of great interest. In the Fourier domain, the acoustic energy of a wave is concentrated along the wave-number frequency (k-ω) dispersion curve, a way to extract one wave from others is to filter the signals by mean of k-ω band-pass area that keeps only the selected surface wave. The objective of the present paper is to propose 2D Finite Impulse Response (FIR) filters based on an arbitrary area shape designed to extract selected waves. FIR filtering is based on convolving the impulse response of the filter with the signals. Impulse responses derived from using k-ω elliptical areas (E-FIR) are presented. The E-FIR filters are successfully tested on three experimental space-time signals corresponding to the propagation of Lamb waves measured by standard transducers on a cylindrical shell, by laser Doppler on a plate and generated by a circular pulse and observed by shearography on a rectangular plate.
Journal of Physics: Conference Series, 2009
Laser ultrasonics allow the observation of transient surface waves along their propagation media ... more Laser ultrasonics allow the observation of transient surface waves along their propagation media and their interaction with encountered objects like cracks, holes, borders. In order to characterize and localize these transient aspects in the Space-Time-Wave number-Frequency domains, the 1D, 2D and 3D Gabor transforms are presented. The Gabor transform enables the identification of several properties of the local wavefronts such as their shape, wavelength, frequency, attenuation, group velocity and the full conversion sequence along propagation. The ability of local properties identification by Gabor transform is illustrated by two experimental studies: Lamb waves generated by an annular source on a circular quartz and Lamb wave interaction with a fluid droplet. In both cases, results obtained with Gabor transform enable ones to identify the observed local waves.
IEEE Sensors Journal, 2000
This paper is a study of a new sensor for fluid characterization. This sensor is composed of a st... more This paper is a study of a new sensor for fluid characterization. This sensor is composed of a stainless steel plate in contact with a viscous material. The aim is to characterize the material viscosity by using reflected Lamb waves at the boundary interface. In order to identify the effects on the Lamb reflected modes by the viscous material, a complete study of the propagation wave in the alone plate is first presented. The propagation modes of the loaded plate are then investigated. By monitoring the mechanical impedance, the viscosity of the material in contact is extracted. In order to validate the experimental set-up, the mechanical impedance variation is measured for different water-glycerol mixtures. Results are in good agreement with those obtained by other techniques in the literature.
Spectrochimica Acta Part B: Atomic Spectroscopy, 2015
Spectrochimica Acta Part B Atomic Spectroscopy
The aim of this paper is to identify the different periods of construction or restoration of the ... more The aim of this paper is to identify the different periods of construction or restoration of the lead roof of a historic monument. Trace elements in a lead matrix can be a signature of the metallurgical processes, allowing identification of a specific time period for the production of the lead used to build the roof. The ability of LIBS (Laser Induced Breakdown Spectroscopy) to detect such trace elements in a lead matrix is therefore explored and checked by comparing its results with LA-ICP-MS as a reference method (Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry). Concentrations of 263 samples were compared between LIBS and LA-ICP-MS data and their correlation was evaluated. Another way to compare their results is also suggested by combining PCA (Principal Component Analysis) and GIS (Geographic Information System). As a result statistical mappings were created, highlighting metallurgical groups of samples across the roof of the building. This innovative approach links ...
Spectrochimica Acta Part B: Atomic Spectroscopy, 2015
ABSTRACT The aim of this paper is to identify the different periods of construction or restoratio... more ABSTRACT The aim of this paper is to identify the different periods of construction or restoration of the lead roof of a historic monument. Trace elements in a lead matrix can be a signature of the metallurgical processes, allowing identification of a specific time period for the production of the lead used to build the roof. The ability of LIBS (Laser Induced Breakdown Spectroscopy) to detect such trace elements in a lead matrix is therefore explored and checked by comparing its results with LA-ICP-MS as a reference method (Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry). Concentrations of 263 samples were compared between LIBS and LA-ICP-MS data and their correlation was evaluated. Another way to compare their results is also suggested by combining PCA (Principal Component Analysis) and GIS (Geographic Information System). As a result statistical mappings were created, highlighting metallurgical groups of samples across the roof of the building. This innovative approach links concentration and spatial location resulting in an easily interpretable graphical presentation of the data.
Ultrasonics, 2006
This paper deals with a study of the conversion of a Lamb wave at the loaded edge of a plate. An ... more This paper deals with a study of the conversion of a Lamb wave at the loaded edge of a plate. An experimental study is performed to know the interaction of surface waves with a viscoelastic material. A Lamb wave is generated by a wedge. At the end of the plate, this wave gives rise to several reflected waves. A first study makes it possible qualitatively to know the Lamb modes present in reflection. Secondly, conversion phenomena are studied to know if surface waves are sensitive to evolution in the time of the viscoelastic material structure. The selected material is a sol-gel containing silica.
2011 IEEE International Ultrasonics Symposium, 2011
ABSTRACT The optimization of new soft hybrid materials elaborated from liquid phase needs an “on ... more ABSTRACT The optimization of new soft hybrid materials elaborated from liquid phase needs an “on line” monitoring during the first steps of their formation. Up to date, few ultrasonic techniques ensure a complete tracking of the material characteristics. They often require a wired excitation particularly unsuited for hidden areas monitoring. This work presents an innovative magneto-ultrasonic sensor remotely controlled by an RF induction (at 100 MHz) in order to extract rheological properties of hidden complex fluids. An equivalent electrical model of the interactions between the developed wireless sensor and the complex fluid in contact is also presented. The validation study of this model using well-known viscous fluids (water-glycerol mixtures) is furthermore achieved.
Ultrasonics, 2006
Laser ultrasonic detection is a versatile and highly sensitive tool for the observation of surfac... more Laser ultrasonic detection is a versatile and highly sensitive tool for the observation of surface waves. In the following study, laser ultrasonic detection is used for the experimental study of spurious normal vibration modes of a disk quartz sensor excited by a voltage pulse. The AT cut crystal (cut of the crystal relative to the the main crystallographic axis is 35.25 degrees) is optimal for generating mainly thickness-shear vibrations (central frequency 6 MHz) on the quartz surface. However, resulting from shear-to-longitudinal and shear-to-surface mode conversion, and from the weak coupling with the other crystallographic axes, other modes (thickness-compressional and bending modes) are always present in the plate response. Since the laser vibrometer is sensitive to normal displacements, the laser investigation shows waves that can be considered as unwanted for the AT quartz used as a shear sensor. The scanned three dimensional (3D) amplitude-space-time signals are carefully analysed using their representation in three dual Fourier domains (space-time, wave number-frequency). Results on the transient analysis of the waves, the normal bending modes and the dispersion curves are shown.
2011 IEEE International Ultrasonics Symposium, 2011
ABSTRACT Bacterial adhesion and proliferation through biofilm is a major concern in industrial ap... more ABSTRACT Bacterial adhesion and proliferation through biofilm is a major concern in industrial applications where surfaces are in contact with aqueous fluids. Bacteria in these environments are capable of rapid attachment and community development on those surfaces. NDT can play an important role thanks to its capability to monitor bio-physical properties. In this study, a simple technique to monitor the rheological properties of S. Cerevisiae growth at microscopic scale is proposed. This technique uses shear waves generated by an AT-cut quartz crystal at 5 MHz. In order to optimize growing conditions, the temperature, pH and substrate on which the yeast grows are tightly controlled. This grow is performed under aerobic conditions. Using a suitable model including the electrical properties evolution during S. Cerevisiae cultivation, the rheological properties elastic and viscous moduli (respectively G' and G") can be accurately extracted. Thanks to the high sensitivity of the proposed technique, the ultradian mechanical oscillation of the entire yeast culture is observed. This preliminary micro-rheological monitoring study makes possible the online optimization of bioethanol production.
2010 IEEE International Ultrasonics Symposium, 2010
Abstract The sol-gel process is currently used to develop new materials with a wide range of appl... more Abstract The sol-gel process is currently used to develop new materials with a wide range of applications in chemical and food industries. An ultrasonic self-calibrated method is used to evaluate the behavior of the nonlinear coefficient during the sol to gel reaction. The ...
Ultrasonics, 2012
In many industrial processes where online control is necessary such as in the food industry, the ... more In many industrial processes where online control is necessary such as in the food industry, the real time monitoring of visco-elastic properties is essential to ensure the quantity of production. Acoustic methods have shown that reliable properties could be obtained from measurements of velocity and attenuation. This paper proposes a simple, real time ultrasound method for monitoring linear medium properties (phase velocity and attenuation) that vary in time. The method is based on a pulse echo measurement and is self-calibrated. Results on a silica gel are reported and the importance of taking into account the changes of the mechanical loading on the front face of the transducer will be shown. This is done through a modification of the emission and reception transfer parameters. The simultaneous measurement of the input and output currents and voltages enables these parameters to be calculated during the reaction. The variations of the transfer parameters are in the order of 6% and predominate other effects. The evolution of the ultrasonic longitudinal wave phase velocity and attenuation as a function of time allows the characteristic times of the chemical reaction to be determined. The results are well correlated with the gelation time measured by rheological method at low frequency.