Alain Sommier

Institut de Mécanique et d'Ingénierie de Bordeaux | I2M Bordeaux · TREFLE

The investigation of humidity movement during drying or imbibition processes represents a serious challenge for several industries, such as the wood-based material industry and paper industry. Recently, several studies have been conducted on the efficiency contactless Terahertz technique (THz) to map the water content. In this study, this technique...

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...

Microfluidic fuel cells (MFC) are micro-scale energy conversion systems where electrochemical reactions take place on two electrodes separated by an electrolyte. The mass diffusion of the reactants plays a crucial role in these reactions since it governs both the electrochemical and fuel utilization efficiency of the MFC. In this work, we measured...

Contactless temperature field measurements in or at the surfaces of semitransparent media are a scientific challenge as classical thermography techniques based on proper material emission cannot be used. In this work, an alternative method using infrared thermotransmittance for contactless temperature imaging is proposed. To overcome the weakness o...

Temperature field contactless measurements in or at the surfaces of semitransparent media are a scientific challenge, as classical thermography techniques based on proper material emission cannot be used. In this work, an alternative method using infrared thermotransmittance for contactless imaging temperatures is proposed. To overcome the weakness...

In this paper we report a semianalytical model of the mass transfer impedance in microfluidic electrochemical chips (MEC). It is based on the molar advection diffusion equation in a microfluidic channel with a Poiseuille flow and an electrochemical reaction at the interface of deposited electrodes. Using the Fourier-Laplace integral transforms and...

Microfluidic fuel cells (MFCs) are microfluidic electrochemical conversion devices that are used to power small pieces of electrical equipment. Their performance relies on the improvement of the mass transfer of the reactants at the electrode interface. In this work, a novel operando imaging technique to measure the chemical concentration fields in...

The knowledge of the power spatial distribution of flux is of great interest for the quantification of heat sources. In this work, we describe the development of contactless imaging powermeter based on the association bolometer-IR camera. This powermeter coupled to the mathematical processing of images enable the reconstruction of the power spatial...

Knowledge 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 in...

Conservation of artworks is of paramount importance nowadays around the world. Clever conservation by using non-destructive testing (NDT) techniques is highly appreciated by restorers and art historians. Among these, a special set-up working into the infrared region is the flying spot laser thermography technique that uses a punctual stimulus to tr...

Temperature field measurements need to be performed in many research areas to ensure an accurate control of numerous systems, such as in material sciences or biology. However, for infrared semi-transparent objects, like living cells or semiconductors, infrared thermography is not well-suited.To address this purpose, we used the thermal dependence o...

A super-resolution method based on laser Flying Spot technique and InfraRed (IR) thermography is proposed. The thermal resolution given by an IR camera is limited by the pixel dimensions of the camera. The objective of this work is to achieve a better resolution through the displacement of a laser spot that is smaller than the pixel. The study of t...

Knowledge 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.In this work, we describe the development of a contactless infrared and multispectral imaging technique based on the pyro-reflectome...

In this paper, a method based on Bayesian inference is proposed to conjointly estimate the following two fields of thermophysical parameters. The first is a thermal characteristic time directly linked to the thermal diffusivity and the thickness, whereas the second is the Biot number, which is directly linked to the heat loss and thermal conductivi...

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 reconstr...

In this work, a novel image-based method is presented to characterize the heat and mass transfer rates in a Hele-Shaw microfluidic reactor. A Fourier transform infrared (FTIR) spectrometer is used in transmission mode in combination with an infrared (IR) camera to simultaneously measure the molar concentration and the thermal fields in the microflu...

In this paper, we addressed the problem of quantitatively measuring the profile of bilayer media. A contactless thermal profilometry method is proposed. Concretely, this approach corresponds to measuring the interface between two media of a material. An experimental setup is proposed, and a methodology is presented to estimate the profile . Two exa...

La torche à plasma est un type de source qui génère de très hautes températures et flux, qui nécessite d'être caractérisée en vue de leur optimisation énergétique. La mesure de ces hautes températures implique l'utilisation de méthodes non intrusives. Une méthode basée sur la spectroscopie IR permettant la mesure simultanée de l'émissivité et de la...

This 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 mount...

This study has illustrated the potentials of optical and THz infrared thermography in the identification of inserts of different nature in glass fiber reinforced polymer. The inspection efficiency has been comparatively evaluated by applying the Tanimoto criterion. The best test procedure has proven to be one-sided stationary thermal nondestructive...

With the aid of a grant ADEME-TOTAL, we instrumented a filtering centrifuge to model the coupling of mechanical dewatering and thermal drying by microwave. Our objectives are the optimization of energy consumption of coupled process and the demonstration that the coupled process can be more efficient than convective drying regarding energy consumpt...

The aim of the present work is to propose a methodology for the use of thermoelectric modules (TEM) as an alternative to conventional heat flux sensors, for estimating convective and radiative heat flux. In this experimental study, the performance of TEMs as heat flux sensors is compared to that of the heat flux sensor (HFS), a type of conventional...

The main goal of this paper is the estimation of thermal resistive fields in multilayer samples using the classical front face flash method as excitation and InfRared Thermography (IRT) as a monitoring sensor. The complete inverse processing of a multilayer analytical model can be difficult due to a lack of sensitivity to certain parameters (layer...

In this paper, the problem of the quantitative characterization of thermal resistance fields in a multilayer sample is addressed by using the classical front face flash method as the thermal excitation and infrared thermography (IRT) as the monitoring sensor. In this challenging problem, the complete inverse processing of a multilayer analytical mo...

The front face photothermal radiometry technique has been improved in order to estimate the thermal conductivity of thin films with better accuracy compared to existing techniques. The experimental procedure is based on the front face response to a nanoseconds laser pulse repeated periodically at high frequency, i. e., a Dirac comb waveform. Averag...

A new process for extraction of essential oils from orange peels (Citrus sinensis L.) using microwave and centrifugal (MW/C) force was studied. MW/C is a combination of microwave heating to explode the internal cells of biological material, and centrifugation to intensify diffusion, collection and separation of compounds of interest. MW/C is perfor...

The domain of non-destructive testing (NDT) or thermal characterization is currently often done by using contactless methods based on the use of an IR camera to monitor the transient temperature response of a system or sample warmed by using any heat source. Though many techniques use optical excitation (flash lamps, lasers, etc.), some techniques...

Non-destructive testing (NDT) of materials and structures is a very important industrial issue in the fields of transport, aeronautics and space as well as in the medical domain. Active infrared thermography is an NDT method that consists of providing an external excitation to cause an elevation of the temperature field in the material, consequentl...

We have obtained an analytical expression for the surface temperature of a sample that is moving at constant velocity when it is illuminated by a modulated and focused laser beam, which remains at rest. From this expression it is found that while the temperature amplitude thermogram shows the expected elongated shape in the direction of the sample...

The Flying-Spot infrared thermography was introduced more than twenty years ago to detect narrow cracks. Recent progress made in optical control, lasers and infrared cameras allows extending the Flying-Spot technique for a quantitative thermal analysis. In this work, we propose a Constant Velocity Flying Spot to measure the in-plane thermal diffusi...

Considering the use of Peltier modules as alternatives to conventional flux meters, an experimental evaluation comparing these two types of sensors is discussed here. The interest in performing this evaluation lies in the difference in the cost and the higher thermoelectric power of Peltier modules compared to conventional flux meters. The results...

Constant Velocity Flying-Spot thermography consists in scanning the sample surface by a focused CW-laser spot moving at constant speed. This technique was designed to study large surfaces in short times. In this work, we propose a method, based on a Flying-Spot thermography setup, to size the width of vertical cracks by fitting the temperature prof...

This paper deals of limestone samples electrical resistivity measurements technique. It uses carbon plate electrodes as both current injection electrodes and potential electrodes. The data treatments uses a modified Archie's law inspired from Glover works. We showed that the samples resistivity is close to the one we measured on site.

This chapter aims at introducing basic features of dielectric heating and to present the applications in the food industry. Based on a literature survey of recent works, many examples are given to highlight the main advantages of the microwave (MW) technology in food processing. The case of most processes involving heating is addressed. From anothe...

This chapter aims at introducing basic features of dielectric heating and to present the applications in the food industry. Based on a literature survey of recent works, many examples are given to highlight the main advantages of the microwave (MW) technology in food processing. The case of most processes involving heating is addressed. From anothe...

In this work, an infrared thermography setup is proposed to measure the in-plane thermal diffusivity of (an)isotropic samples that are moving at constant velocity, as it is the case of in-line production or in-line quality control processes in factories. The experiment consists in heating the moving sample with a focused laser spot, which remains a...

THz waves have shown to be effective for several applications, such as security, non-destructive testing, and water content monitoring for porous materials and food products. This study aims to highlight the use of THz radiation to measure temperature variations of thin insulating materials opaque in the visible or IR range (PVC, PTFE, PMMA, and wo...

In a previous work we developed methods based on Pulsed Flying Spot (PFS) to measure the in-plane thermal diffusivity of (an)isotropic materials. Due to the optical laser scanning system, the effective measurement area is around 5 cm x 5cm) to obtain a good spatial resolution and to ensure accurate estimated thermal fields. First, to extend the pre...

Measuring and modelling the permeability of tight rocks remains a challenging task. In addition to the traditional sources of errors that affect more permeable formations (e.g. sample selection, non-representative specimens, disturbance introduced during sample acquisition and preparation), tight rocks can be particularly prone to solid–fluid inter...

Measuring the permeability of tight rocks remains a challenging task. In addition to the traditional sources of errors that affect more permeable formations (e.g. sample selection, non-representative specimens, disturbance introduced during sample acquisition and preparation), tight rocks can be particularly prone to solid–fluid interactions and th...

A new process design and operation for the extraction of polyphenols from fresh lettuce was developed. Microwave assisted centrifugation (MW/C) is a combination of microwave heating to explode the internal cells of biological material containing secondary metabolites, and centrifugation to intensify diffusion, collection and separation. MW/C is per...