https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Sat, 07 Mar 2026 00:29:46 GMT 2026-03-07T00:29:46Z http://hdl.handle.net/10985/25643 Transient Thermal Characterization of Small Particles in Fluidic or Acoustic Levitation BATSALE, Jean-Christophe; AOUALI, Abderezak; ACHCHAQ, Fouzia; SOMMIER, Alain Putting small particles in levitation and in transient thermal imbalance in a gas has several advantages. This avoids chemical and thermal pollution through contact with a solid wall. The large exchange surface between the particle and the surrounding gas and the small volume can be considered as microfluidic situations with acceleration of surface transfers, rapidly isothermal particles, low-cost thermal cycling, rapidly isothermal situations and extreme temperature conditions facilitated. Several results related to thermal characterization in the case of fluidic and acoustic methods of levitation are presented. It consists of recording and comparing the transient temperature response by using an infrared thermography device to a step convective or radiative heating. Thu, 04 Jul 2024 00:00:00 GMT http://hdl.handle.net/10985/25643 2024-07-04T00:00:00Z BATSALE, Jean-Christophe AOUALI, Abderezak ACHCHAQ, Fouzia SOMMIER, Alain Putting small particles in levitation and in transient thermal imbalance in a gas has several advantages. This avoids chemical and thermal pollution through contact with a solid wall. The large exchange surface between the particle and the surrounding gas and the small volume can be considered as microfluidic situations with acceleration of surface transfers, rapidly isothermal particles, low-cost thermal cycling, rapidly isothermal situations and extreme temperature conditions facilitated. Several results related to thermal characterization in the case of fluidic and acoustic methods of levitation are presented. It consists of recording and comparing the transient temperature response by using an infrared thermography device to a step convective or radiative heating. http://hdl.handle.net/10985/24816 Terahertz Constant Velocity Flying Spot for 3D Tomographic Imaging AOUALI, Abderezak; CHEVALIER, Stéphane; SOMMIER, Alain; PRADERE, Christophe This work reports on a terahertz tomography technique using constant velocity flying spot scanning as illumination. This technique is essentially based on the combination of a hyperspectral thermoconverter and an infrared camera used as a sensor, a source of terahertz radiation held on a translation scanner, and a vial of hydroalcoholic gel used as a sample and mounted on a rotating stage for the measurement of its absorbance at several angular positions. From the projections made in 2.5 h and expressed in terms of sinograms, the 3D volume of the absorption coefficient of the vial is reconstructed by a back-projection method based on the inverse Radon transform. This result confirms that this technique is usable on samples of complex and nonaxisymmetric shapes; moreover, it allows 3D qualitative chemical information with a possible phase separation in the terahertz spectral range to be obtained in heterogeneous and complex semitransparent media. Wed, 31 May 2023 00:00:00 GMT http://hdl.handle.net/10985/24816 2023-05-31T00:00:00Z AOUALI, Abderezak CHEVALIER, Stéphane SOMMIER, Alain PRADERE, Christophe This work reports on a terahertz tomography technique using constant velocity flying spot scanning as illumination. This technique is essentially based on the combination of a hyperspectral thermoconverter and an infrared camera used as a sensor, a source of terahertz radiation held on a translation scanner, and a vial of hydroalcoholic gel used as a sample and mounted on a rotating stage for the measurement of its absorbance at several angular positions. From the projections made in 2.5 h and expressed in terms of sinograms, the 3D volume of the absorption coefficient of the vial is reconstructed by a back-projection method based on the inverse Radon transform. This result confirms that this technique is usable on samples of complex and nonaxisymmetric shapes; moreover, it allows 3D qualitative chemical information with a possible phase separation in the terahertz spectral range to be obtained in heterogeneous and complex semitransparent media. http://hdl.handle.net/10985/24819 High power density laser estimation using quantitative thermal imaging method AOUALI, Abderezak; LAFARGUE-TALLET, Thomas; CHEVALIER, Stéphane; SOMMIER, Alain; PEIFFER, Raymond; TAILLANDIER, Maximilian; BATSALE, Jean-Christophe; PRADERE, Christophe The knowledge of the amplitude and the spatial distribution of an excitation flux is of great interest for the quantification of heat sources. In this work, the development of a non-contact imaging powermeter based on the association of a bolometer with an infrared camera is described. This powermeter allows, thanks to infrared thermographic measurements and image processing methods, the quantitative estimation of the spatial distribution of the power of the flux delivered by a high-power laser. First, the experimental setup used is described. Then, the complete model- ling of the heat transfer within the bolometer using the 3D thermal quadrupole formalism is presented. After that, an inverse method based on the Wiener filter in Fourier-Laplace transform spaces to estimate the spatial distribution of the power flux is described. Finally, power estimation results using two metallic plates as a bolometer are presented and discussed Thu, 06 Jul 2023 00:00:00 GMT http://hdl.handle.net/10985/24819 2023-07-06T00:00:00Z AOUALI, Abderezak LAFARGUE-TALLET, Thomas CHEVALIER, Stéphane SOMMIER, Alain PEIFFER, Raymond TAILLANDIER, Maximilian BATSALE, Jean-Christophe PRADERE, Christophe The knowledge of the amplitude and the spatial distribution of an excitation flux is of great interest for the quantification of heat sources. In this work, the development of a non-contact imaging powermeter based on the association of a bolometer with an infrared camera is described. This powermeter allows, thanks to infrared thermographic measurements and image processing methods, the quantitative estimation of the spatial distribution of the power of the flux delivered by a high-power laser. First, the experimental setup used is described. Then, the complete model- ling of the heat transfer within the bolometer using the 3D thermal quadrupole formalism is presented. After that, an inverse method based on the Wiener filter in Fourier-Laplace transform spaces to estimate the spatial distribution of the power flux is described. Finally, power estimation results using two metallic plates as a bolometer are presented and discussed http://hdl.handle.net/10985/21500 Ultra-broadband contactless imaging power meter AOUALI, Abderezak; CHEVALIER, Stéphane; SOMMIER, Alain; AYADI, M.; BATSALE, Jean-Christophe; BALAGEAS, Daniel; PRADERE, Christophe Knowledge of the spatial and temporal distribution of heat flux is of great interest for the quantification of heat sources. In this work, we describe the development of a new ultra-broadband contactless imaging power meter based on electromagnetic to infrared technology. This new sensor and the mathematical processing of images enable the reconstruction of both spatial and amplitude distributions through a wide spectral range of sources. The full modeling of the thermoconverter based on 3D formalism of thermal quadrupoles is presented first before deriving a reduced model more suitable for quick and robust inverse processing. The inverse method makes it possible to simultaneously identify the heat losses and the spatial and temporal source distribution for the first time, to the best of our knowledge. Finally, measurements of multispectral sources are presented and discussed, with an emphasis on the spatial and temporal resolution, accuracy and capabilities of the power meter. Fri, 01 Jan 2021 00:00:00 GMT http://hdl.handle.net/10985/21500 2021-01-01T00:00:00Z AOUALI, Abderezak CHEVALIER, Stéphane SOMMIER, Alain AYADI, M. BATSALE, Jean-Christophe BALAGEAS, Daniel PRADERE, Christophe Knowledge of the spatial and temporal distribution of heat flux is of great interest for the quantification of heat sources. In this work, we describe the development of a new ultra-broadband contactless imaging power meter based on electromagnetic to infrared technology. This new sensor and the mathematical processing of images enable the reconstruction of both spatial and amplitude distributions through a wide spectral range of sources. The full modeling of the thermoconverter based on 3D formalism of thermal quadrupoles is presented first before deriving a reduced model more suitable for quick and robust inverse processing. The inverse method makes it possible to simultaneously identify the heat losses and the spatial and temporal source distribution for the first time, to the best of our knowledge. Finally, measurements of multispectral sources are presented and discussed, with an emphasis on the spatial and temporal resolution, accuracy and capabilities of the power meter. http://hdl.handle.net/10985/21496 3D infrared thermospectroscopic imaging AOUALI, Abderezak; CHEVALIER, Stéphane; SOMMIER, Alain; ABISSET-CHAVANNE, Emmanuelle; BATSALE, Jean-Christophe; PRADERE, Christophe AbstractThis work reports a multispectral tomography technique in transmission mode (called 3DITI for 3D Infrared Thermospectroscopic Imaging) based on a middle wavelength infrared (MWIR) focal plane array. This technique relies on an MWIR camera (1.5 to 5.5 μm) used in combination with a multispectral IR monochromator (400 nm to 20 μm), and a sample mounted on a rotary stage for the measurement of its transmittance at several angular positions. Based on the projections expressed in terms of a sinogram, spatial three-dimensional (3D) cubes (proper emission and absorptivity) are reconstructed using a back-projection method based on inverse Radon transform. As a validation case, IR absorptivity tomography of a reflective metallic screw is performed within a very short time, i.e., shorter than 1 min, to monitor 72 angular positions of the sample. Then, the absorptivity and proper emission tomographies of a butane-propane-air burner flame and microfluidic perfluoroalkoxy (PFA) tubing filled with water and ethanol are obtained. These unique data evidence that 3D thermo-chemical information in complex semi-transparent media can be obtained using the proposed 3DITI method. Moreover, this measurement technique presents new problems in the acquisition, storage and processing of big data. In fact, the quantity of reconstructed data can reach several TB (a tomographic sample cube of 1.5 × 1.5 × 3 cm3 is composed of more than 1 million pixels per wavelength). Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/21496 2020-01-01T00:00:00Z AOUALI, Abderezak CHEVALIER, Stéphane SOMMIER, Alain ABISSET-CHAVANNE, Emmanuelle BATSALE, Jean-Christophe PRADERE, Christophe AbstractThis work reports a multispectral tomography technique in transmission mode (called 3DITI for 3D Infrared Thermospectroscopic Imaging) based on a middle wavelength infrared (MWIR) focal plane array. This technique relies on an MWIR camera (1.5 to 5.5 μm) used in combination with a multispectral IR monochromator (400 nm to 20 μm), and a sample mounted on a rotary stage for the measurement of its transmittance at several angular positions. Based on the projections expressed in terms of a sinogram, spatial three-dimensional (3D) cubes (proper emission and absorptivity) are reconstructed using a back-projection method based on inverse Radon transform. As a validation case, IR absorptivity tomography of a reflective metallic screw is performed within a very short time, i.e., shorter than 1 min, to monitor 72 angular positions of the sample. Then, the absorptivity and proper emission tomographies of a butane-propane-air burner flame and microfluidic perfluoroalkoxy (PFA) tubing filled with water and ethanol are obtained. These unique data evidence that 3D thermo-chemical information in complex semi-transparent media can be obtained using the proposed 3DITI method. Moreover, this measurement technique presents new problems in the acquisition, storage and processing of big data. In fact, the quantity of reconstructed data can reach several TB (a tomographic sample cube of 1.5 × 1.5 × 3 cm3 is composed of more than 1 million pixels per wavelength). http://hdl.handle.net/10985/24815 Multiscale aspects of the response of a temperature field to a pulsed laser or a periodic laser spot: some applications for IR thermography for non destructive evaluation, terahertz tomography, super-resolution, and microscale heat transfer BATSALE, Jean-Christophe; ABISSET-CHAVANNE, Emmanuelle; ACHCHAQ, Fouzia; AOUALI, Abderezak; CHEVALIER, Stéphane; GROZ, Marie-Marthe; MAIRE, Jeremie; SOMMIER, Alain The study of the response of a temperature field (recorded from IR cameras) to a laser spot heating is increasingly used for NDE (Non Destructive Evaluation) applications. The most classical type of application is to use the flying spot in order to detect vertical cracks and/or to measure the in plane thermal diffusivity in relation to the observation plane of opaque materials. But several other ways of applications are presented here related to tomography and also super resolution. Instead of opaque materials applications, the tomography is using the principles of the flying spot. It consists in an indirect detection on an intermediate layer (the thermoconverter) that can convert a wide range of radiation from the spot. The objective of super-resolution can also be implemented with flying spot in order to circumvent the low spatial resolution of IR imaging systems. Such methods consider spots whose diameter is small compared to the size of the pixel. Some applications of our team will be shown with multiscale considerations Mon, 12 Jun 2023 00:00:00 GMT http://hdl.handle.net/10985/24815 2023-06-12T00:00:00Z BATSALE, Jean-Christophe ABISSET-CHAVANNE, Emmanuelle ACHCHAQ, Fouzia AOUALI, Abderezak CHEVALIER, Stéphane GROZ, Marie-Marthe MAIRE, Jeremie SOMMIER, Alain The study of the response of a temperature field (recorded from IR cameras) to a laser spot heating is increasingly used for NDE (Non Destructive Evaluation) applications. The most classical type of application is to use the flying spot in order to detect vertical cracks and/or to measure the in plane thermal diffusivity in relation to the observation plane of opaque materials. But several other ways of applications are presented here related to tomography and also super resolution. Instead of opaque materials applications, the tomography is using the principles of the flying spot. It consists in an indirect detection on an intermediate layer (the thermoconverter) that can convert a wide range of radiation from the spot. The objective of super-resolution can also be implemented with flying spot in order to circumvent the low spatial resolution of IR imaging systems. Such methods consider spots whose diameter is small compared to the size of the pixel. Some applications of our team will be shown with multiscale considerations http://hdl.handle.net/10985/23071 Active thermo-reflectometry for absolute temperature measurement by infrared thermography on specular materials LAFARGUE-TALLET, Thomas; VAUCELLE, Romain; CALIOT, Cyril; AOUALI, Abderezak; ABISSET-CHAVANNE, Emmanuelle; SOMMIER, Alain; PEIFFER, Raymond; PRADERE, Christophe AbstractKnowledge of material emissivity maps and their true temperatures is of great interest for contactless process monitoring and control with infrared cameras when strong heat transfer and temperature change are involved. This approach is always followed by emissivity or reflections issues. In this work, we describe the development of a contactless infrared imaging technique based on the pyro-reflectometry approach and a specular model of the material reflection in order to overcome emissivities and reflections problems. This approach enables in situ and real-time identification of emissivity fields and autocalibration of the radiative intensity leaving the sample by using a black body equivalent ratio. This is done to obtain the absolute temperature field of any specular material using the infrared wavelength. The presented set up works for both camera and pyrometer regardless of the spectral range. The proposed method is evaluated at room temperature with several heterogeneous samples covering a large range of emissivity values. From these emissivity fields, raw and heterogeneous measured radiative fluxes are transformed into complete absolute temperature fields. Thu, 12 May 2022 00:00:00 GMT http://hdl.handle.net/10985/23071 2022-05-12T00:00:00Z LAFARGUE-TALLET, Thomas VAUCELLE, Romain CALIOT, Cyril AOUALI, Abderezak ABISSET-CHAVANNE, Emmanuelle SOMMIER, Alain PEIFFER, Raymond PRADERE, Christophe AbstractKnowledge of material emissivity maps and their true temperatures is of great interest for contactless process monitoring and control with infrared cameras when strong heat transfer and temperature change are involved. This approach is always followed by emissivity or reflections issues. In this work, we describe the development of a contactless infrared imaging technique based on the pyro-reflectometry approach and a specular model of the material reflection in order to overcome emissivities and reflections problems. This approach enables in situ and real-time identification of emissivity fields and autocalibration of the radiative intensity leaving the sample by using a black body equivalent ratio. This is done to obtain the absolute temperature field of any specular material using the infrared wavelength. The presented set up works for both camera and pyrometer regardless of the spectral range. The proposed method is evaluated at room temperature with several heterogeneous samples covering a large range of emissivity values. From these emissivity fields, raw and heterogeneous measured radiative fluxes are transformed into complete absolute temperature fields.