About
83
Publications
7,448
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
492
Citations
Introduction
Additional affiliations
January 2000 - present
Education
May 2008 - May 2012
Publications
Publications (83)
Photovoltaic panels are an important source of renewable energy but also represent a growing stock of complex electronic waste. Specific recycling processes are required and this article investigates the potential of supercritical CO2 foaming of the ethylene-vinyl acetate (EVA) in photovoltaic modules as a means of safely taking them apart, layer b...
The study and development of present and future processes for the treatment/recycling of spent nuclear fuels require many steps, from design in the laboratory to setting up on an industrial scale. In all of these steps, analysis and instrumentation are key points. For scientific reasons (small-scale studies, control of phenomena, etc.) but also wit...
The analysis of nano-and microparticle suspensions with micro systems affords improved space-time yields, selectivity, reaction residence times and conversions capabilities. These capabilities are of primary importance in various fields of research and industry. The few microfluidic lab-on-a-chip approaches that have been developed are essentially...
The analysis of nano- and microparticle suspensions with micro systems affords
improved space–time yields, selectivity, reaction residence times and conversions capabilities.
These capabilities are of primary importance in various fields of research and industry. The
few microfluidic lab-on-a-chip approaches that have been developed are essentially...
This paper presents a new method for estimating the parameters of a stochastic geometric model for multiphase flow image processing using local measures. Local measures differ from global measures in that they are only based on a small part of a binary image and consequently provide different information of certain properties such as area and perim...
The delamination of photovoltaic modules with supercritical CO2 is an interesting approach to integrate photovoltaics into a circular economy. This article describes the first phase of this process: the absorption of CO2 into poly(ethylene-co-vinyl acetate) (EVA-28), one of the layers in a photovoltaic module. The swelling of the polymer, determine...
The paper focuses on a new method for the inference of a parametric random spheroid from the observations of its 2D orthogonal projections. Such a stereological problem is well-known from the literature when the projections come from only one deterministic spheroid. Nevertheless, when the spheroid is random itself, the estimation of its distributio...
Microfluidics have many potential applications including characterization of chemical processes on a reduced scale, spanning the study of reaction kinetics using on-chip liquid-liquid extractions, sample pretreatment to simplify off-chip analysis, and for portable spectroscopic analyses. The use of in situ characterization of process streams from l...
The use of microfluidics technology and the miniaturization of analytical techniques is of high interest for the chemical and nuclear industries. In the latter, the reduction of effluents deriving from actinides concentration monitoring along R&D and pilot-scale purification processes is a permanent concern. Indeed, the extremely harsh operation co...
A joint experimental and simulation study of a gas-liquid flow with non-quiescent liquid is presented, in the case of a small-gap geometry, such as the ones implemented in nuclear fuel recycling processes to mitigate criticality issues. The numerical model is based on a Euler-Euler approach that has been selected and tested on existing data publish...
This paper reports on original experimental data of mixing in two-phase Taylor–Couette flows. Neutrally buoyant particles with increasing volume concentration enhance significantly mixing of a passive tracer injected within the gap between two concentric cylinders. Mixing efficiency is measured by planar laser-induced fluorescence coupled to partic...
Physical insights are provided on the relative contributions of the scattering processes (pure diffraction, specular reflection, tunneling and grazing waves, single refraction…) in the reconstruction of the photonic jet of spherical particles with Digital-in-Line Holography.
In this paper a new approach to geometrically model and characterize 2D silhouette images of two-phase flows is proposed. The method consists of a 3D modeling of the particles population based on some morphological and interaction assumptions. It includes the following steps. First, the main analytical properties of the proposed model – which is an...
L’holographie numérique en ligne est une technique d’imagerie volumétrique particulièrement adaptée à la caractérisation des écoulements dilués qui permet de mesurer simultanément la position dans l’espace, le déplacement, la forme et la taille de particules au sein des ces derniers (bulles, gouttes, etc.). Dans de nombreux domaines, qu’ils concern...
Cette communication s’inscrit dans le cadre des recherches sur les procédés d’extraction liquide-liquide utilisés pour le retraitement du combustible nucléaire. Le besoin d’améliorer les capacités et de réduire le coût de développement de la nouvelle génération de colonnes d’extraction impose le déploiement d’outils de simulation dûment validés. Da...
Cette communication s’inscrit dans le cadre des recherches sur les procédés d’extraction liquide-liquide utilisés pour le retraitement du combustible nucléaire. Le besoin d’améliorer les capacités et de réduire le coût de développement de la nouvelle génération de colonnes d’extraction impose le déploiement d’outils de simulation dûment validés. Da...
The image of the photonic jet (also called caustic) formed by a large, transparent, and spherical particle, reconstructed by digital in-line holography, is shown to be similar to the Airy pattern observed at the focus of a diffraction-limited lens. The analysis of this image, real or virtual depending on whether the particle relative refractive ind...
The authors have shown recently [1, 2] that digital in-line holography (DIH) can recover some features of the electromagnetic near field of large spherical transparent particles. Among these features, a special attention was paid to the photonic jet whose intensity maxima positioning allows to estimate the particle refractive index. In the present...
This communication deals with the optical
characterization of droplets and fluids parameters that are
relevant for liquid-liquid extraction processes, and notably,
for nuclear fuel reprocessing. In immiscible liquid–liquid
dispersions, i.e. droplets with a homogeneous but low value
relative refractive index, the first order rainbow is localized
in...
The reduction of effluents deriving from analytical control is a serious concern in the nuclear industry, for both production and R & D units. In this work we report an alternative methodology for the standard UV-Vis absorbance analyses for acti-nides concentration monitoring along the PUREX (Plutonium Uranium Redox Extraction) process. This method...
Image analysis is a widespread and performant tool for the characterization of particulate systems in chemical engineering. However, for bubbly flows, due to the wide range of particles size, shape and the appearance of large clusters resulting from particles projections overlapping at high hold-up, automatic particle detection remains a challenge....
The capabilities and resolution of the rainbow technique were extended to estimate the size distribution and composition of droplets in liquid–liquid systems. For these droplets, essentially characterized by a low relative refractive index (𝑚≈1.001–1.20), the first-order rainbow is localized in the near-forward to sideways region. It exhibits an un...
Optical methods for investigating multiphase flows are reviewed and discussed in the scope of the development of apparatus convenient for nuclear fuel reprocessing. Indeed, the various processes implemented (e.g. leaching, solvent extraction, filtration, crystallization, etc.) involve either liquid/gas, liquid/liquid and/or liquid/solid flows. Besi...
In industrial solvent extraction units, minimizing the energy input of liquid-liquid contactors is essential. Knowledge of the pressure drop evolution with both geometry and operating conditions is therefore required in order to achieve optimal sizing of the column. In this paper, yet unexplored parameters possibly affecting pressure drop in pulsed...
Optical methods for investigating multiphase flows are reviewed and discussed in the scope of the development of apparatus convenient for nuclear fuel reprocessing. Indeed, the various processes implemented (e.g. leaching, solvent extraction, filtration, crystallization, etc.) involve either liquid/gas, liquid/liquid and/or liquid/solid flows. Besi...
A low cost fabrication process for photonic lab on a chip systems is here proposed. For the implementation of the masters suitable for cast molding fabrication, an inexpensive dry film photoresist, patternable using standard laboratory equipment, is benchmarked against standardized SU-8 masters obtained using UV lithography and systems manufacture...
Digital in-line holography (DH) is widely used to characterize two-phase flows as it allows determining , simultaneously and in one shot, the shape, 3D center position and size of particles. In this communication, two extensions of DH are presented. The first one concerns particles characterization in astigmatic optical systems (e.g. optical lenses...
The capabilities and resolution of the rainbow technique were extended to estimate the size distribution and composition of droplets in homogeneous and hetteregeneous liquid–liquid systems.
Digital in-line holography (DH) is widely used to characterize two-phase flows as it allows de-termining, simultaneously and in one shot, the shape, 3D center position and size of particles. In this communication, two extensions of DH are presented. The first one concerns particles charac-terization in astigmatic optical systems (e.g. optical lense...
An extension of digital in-line holography to particle and particle systems characterization in complex, i.e. astigmatic, propagation media is presented. To simulate and back propagate holograms in such systems, it is shown that generalized propagators and proper sampling conditions can be derived from the generalized diffraction integral defined i...
A new and computationally efficient approach is proposed for determining the refractive index of spherical and transparent particles, in addition to their size and 3D position, using digital in-line holography. The method is based on the localization of the maximum intensity position of the photonic jet with respect to the particle center retrieved...
The design of separation processes for nuclear spend fuel treatment, dedicated to either R&D studies or industrial applications, is currently based on a phenomenological approach, relying on Computational Fluid Dynamics, and complemented by validation tests achieved at small-scale. Indeed, most of the steps of the PUREX® process involve multiphasic...
Une « Transformée d'Huygens-Fresnel Généralisée» (THFG) est introduite afin de prendre en compte l'astigmatisme induit par des éléments optiques dans le cadre de la théorie de la diffraction scalaire et de l'optique paraxiale [1]. La THFG, avec une réponse impulsionnelle et des conditions d'échantillonnage idoines, permet une implémentation rigoure...
La transformée de Fresnel généralisée est étendue afin de prendre en compte l'astigmatisme induit par des éléments optiques en holographie numérique en ligne. Une réponse impulsionnelle et une fonction de transfert généralisées, ainsi que des conditions d'échantillonnage ad hoc, permettent une implémentation rigoureuse de cette transformation. Il e...
Several processes used in nuclear research and industry are based on liquid-liquid extraction. This method is designed for selective separation of products in a mixture. As the transfer occurs at the contact surface between both phases, the characterization of the dispersed phase of the emulsion (size distribution of droplets, shape, etc.) is funda...
Several processes used in nuclear research and industry are based on liquid-liquid extraction. This method is designed for selective separation of products in a mixture. As the transfer occurs at the contact surface between both phases, the characterization of the dispersed phase of the emulsion (size distribution of droplets, shape, etc.) is funda...
Local mixing dynamics was recently investigated experimentally in Taylor-Couette single-phase flow, thanks to simultaneous Particle Image Velocimetry (PIV) and Planar Laser-Induced Fluorescence (PLIF) techniques. The results highlighted the influence of the successive flow bifurcations and the role of azimuthal wave states on the dispersion of dye...
The pulsed column is one of the most used contactors in solvent extraction processes, especially in the nuclear fuel treatment industry and for hydrometallurgical applications. The optimization of solvent extraction operations needs a thorough understanding of the diphasic ows properties inside the apparatus, especially that of the dispersed phase....
This study details the characterization of two phase flows using digital holography in astigmatic systems through a generalized convolution method derived from the Collins formula.
A microfluidic device has been specially developed to enable the study of fast nucleation kinetics involved in precipitation processes. This setup allows drops of two different reagents to be generated synchronously and to coalesce, and ensure the mixing of their reactants within few milliseconds. The results presented in this paper show that dropl...
Liquid-liquid extraction is used in many industrial processes. Such processes involve liquid-liquid flows, called emulsions, which can be successfully characterized by especially suited holographic techniques. Because the droplets are millimeter size, a near-field diffraction regime is observed. This regime departs from conventional holography and...
The pulsed column is a widely used technology for liquid–liquid extraction processes in various industries. A thorough understanding of the biphasic flow in the column is essential to achieve process optimization and design. This paper is dedicated to the modelling of the single-phase flow which is strongly influencing the transport, breakage and c...
Liquid–liquid extraction is used in many industrial processes. Such processes involve liquid–liquid flows, called emulsions, which can be successfully characterized by especially suited holographic techniques. Because the droplets are millimeter size, a near-field diffraction regime is observed. This regime departs from conventional holography and...
This paper provides a methodological study of geostatistical approaches suitable to radiological evaluation in nuclear premises. By modelling the spatial continuity of activities, geostatistics provide sound methods to estimate and map surface activities, together with their uncertainty. The paper first recalls the main geostatistical principles, t...
Hydrometallurgical processes involve three-dimensional two-phase flows for liquid-liquid extraction and they are not well understood. Optimizing the operation of these devices involves the determination of the fundamental characteristics of the emulsion — and in particular the fluid flow velocities and fluid mixing characteristics — by measuring pa...
Several processes used in research and industry are based on liquid-liquid extraction, a method designed for selective separation of products in a mixture. In liquid-liquid extraction, two immiscible liquids are contacted: an aqueous phase and an organic phase, one of which generally contains an extractant molecule capable of transferring the desir...
This article deals with a direct application of digital in line holography to liquid droplets dispersed in a continuous liquid phase. The droplet size imposes a regime of intermediate-field diffraction hardly explored to date. Acquired diffraction patterns show that the usual dark disk model is not valid and that good agreement is obtained with a m...
An alternative to the current method of reprocessing spent nuclear fuel would be to co-extract the actinides and to co-precipitate them in a single step. In this scope, we are studying a new process based on continuous oxalic precipitation in emulsion using a pulsed column.
A thorough understanding of the precipitation mechanisms and their interac...
An alternative to the current method of reprocessing spent nuclear fuel would be to co-extract the actinides and to co-precipitate them in a single step. A new process of reprocessing spent nuclear fuel based on continuous oxalic precipitation in emulsion using a pulsed column was proposed. The behavior of the aqueous droplets inside the column was...
This paper provides a methodological study of geostatistical approaches suitable to radiological evaluation in nuclear premises. By modelling the spatial continuity of activities, geostatistics provide sound methods to estimate and map surface activities, together with their uncertainty. The paper first recalls the main geostatistical principles, t...
The sIGAle code is developed by CEA LIST at the request of CEA DEN to analyse spectra measured with CdZnTe detectors. sIGAle is a specific automatic analysis software which allows a complete analysis of the spectrum, with automatic calibration, identification of radionuclides present in the spectrum, determination of fluence rates for each signific...
The CEA's Aladin gamma imaging system has been operated successfully for several years in nuclear plants and during decommissioning projects with additional tools such as gamma spectrometry detectors and dose rate probes. The radiological information supplied by these devices is becoming increasingly useful for establishing robust and optimized dec...
Decommissioning a nuclear facility implies a policy of limiting the waste volume and its chemical - and especially radiological - toxicity. It is therefore important to determine the activity level contained in each component that will be dismantled. A variety of methods and analysis techniques are used for this purpose, ranging from simple dose ra...
