Fabrice R A Onofri

French National Centre for Scientific Research | CNRS · Institute for Engineering and Systems Sciences (INSIS)

A numerically effective approach was developed for the modeling of spray-drying of colloidal suspensions. This approach was based on the integration of two models. The first is a phenomenological and radially symmetric model accounting for the drying of single-droplets, while the second employs computational fluid dynamics (CFD) simulations to acco...

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 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...

The scattering patterns near the primary rainbow of oblate drops are simulated by extending the vectorial complex ray model (VCRM) [1] to three-dimensional (3D) calculations. With the curvature of wavefront as intrinsic property of a ray, this advanced ray model permits, in principle, to predict the amplitudes and phases of all emergent rays with a...

The scattering patterns near the primary rainbow of oblate drops are simulated by extending the vectorial complex ray model (VCRM) [Opt. Lett. 36, 370 (2011)] to threedimensional (3D) calculations. With the curvature of a wavefront as an intrinsic property of a ray, this advanced ray model permits, in principle, to predict the amplitudes and phases...

Poster

Poster of the LIP2022

This special issue contains a collection of research papers initially intended to be presented in 2020 at the international conference series on “Laser-light and Interactions with Particles (LIP)” which was postponed, due to the Covid pandemic. Conference or not, the pandemic has not stopped Science. We think that this special issue will help to p...

The present preface for the “no-shown” (i.e. covid pandemic) International Laser-light and interactions with particles conference - 2020 (LIP2020) compiles and reviews 23 peer-reviewed papers, providing a significant sample of the issues usually discussed during LIP-conferences.Authors and readers are kindly asked to forgive the authors of the pres...

This windows-based software allows generating fractal aggregates of spherical particles. It uses a Diffusion Limited Aggregation (DLA) algorithm and the so-called fractal equation. The latter is respected, with a prescribed accuracy, at each aggregation step and for a given set of tunable parameters. The software outputs may be used for light scatt...

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.

Previous JQSRT special issues devoted to the “Laser-light and Interactions with Particles (LIP)” conferences were accompanied by prefaces written for issues published in a single volume, followed by peer-reviewer papers based on the topics discussed during the conferences, see Gouesbet and Brunel (2013) [1] in [2], Gouesbet and Onofri (2015) [3] in...

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...

La diffusion de gouttes non-sphériques en lévitation acoustique est étudiée en comparant diagrammes expérimentaux et numériques. Il ressort de ces travaux que sans modèle de diffusion adéquat un changement quasi imperceptible de leur morphologie peut grandement affecter notre capacité à estimer avec précision leur taille et leur température. Avec u...

Cette communication expose les principales caractéristiques d’un banc de diffusion multi angulaire dont les aspects novateurs et la pertinence sont testés par le suivi de la dynamique de déstabilisation d’une suspension de silice. Outre la correction de divers biais optiques, ce banc intègre des algorithmes d’inversion couplant modèles d’agrégation...

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...

L'influence de la non-sphéricité des gouttes sur leurs diagrammes de diffusion est étudiée avec une approximation d'optique géométrique avancée et des expériences réalisées sous lévitation acoustique. Il ressort de ce ces travaux qu'un changement quasi imperceptible de la morphologie des gouttes peut affecter significativement leurs propriétés de d...

Cette communication expose les principales caractéristiques d'un banc de diffusion multi angulaire dont les aspects novateurs et la pertinence sont testés par le suivi de la dynamique de déstabilisation d'une suspension de silice. Outre la correction de divers biais optiques, ce banc intègre des algorithmes d'inversion couplant modèles d'agrégation...

The influence of droplet non-sphericity on their rainbow angle scattering patterns is investigated with the Vectorial Complex Ray Model (VCRM) and experiments carried under acoustic levitation. It is shown that quasi-imperceptible change in the morphology of droplets can significantly affect the resolution achievable on the determination of their s...

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 influence of droplet non-sphericity on their rainbow angle scattering patterns is investigated with the Vectorial Complex Ray Model (VCRM) and experiments carried under acoustic levitation. It is shown that quasi-imperceptible change in the morphology of droplets can significantly affect the resolution achievable on the determination of their s...

This review highlights the various electromagnetic methods, geometrical and physical optics approximations developed so far in the literature to predict the light scattering properties of large bubbles in an optically dilute regime. The underlying problematic is essentially linked to the characterization of bubbly flows or, more generally, multipha...

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...

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...

G. Gouesbet and F. Onofri Laser-light and Interactions with Particles (LIP), 2016 Journal of Quantitative Spectroscopy & Radiative Transfer 195 (2017) 1–7 http://dx.doi.org/10.1016/j.jqsrt.2017.01.017 This is the preface to a JQSRT special issue devoted to the “Laser-light and Interactions with Particles (LIP)” conference which took place in Xidia...

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.

We report the first experimental validation of the Vectorial Complex Ray Model (VCRM) using the scattering patterns of large oblate droplets trapped in an acoustic field. The two principal radii and refractive index of the droplets are retrieved with a minimization method that involves VCRM predictions and experimental light scattering patterns. Th...

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...

Ge-imogolite nanotubes (Al2GeO7H4) can be readily obtained in various lengths, chemical compositions and crystallinities, opening up new perspectives for applications. Their classical synthesis includes the nucleation of roof-tile shaped precursors at room temperature followed by a heat promoted growth (typically 95 °C) for at least 4 to 7 days. To...

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...

In this article, a detailed introduction of the light extinction spectrometry (LES) diagnostics is given. LES allows the direct in situ measurement of the particle size distribution and absolute concentration of dust clouds levitating in plasmas. Using a relatively simple and compact experimental set-up, the dust cloud parameters can be recovered w...

Various geometrical and physical effects regarding the scattering of large bubbles are revisited to develop an extended GPOA. Basically, in all developed models the GOA introduced by Van de Hulst is used to describe the scattering patterns outside the singular regions. This model, when properly implemented, provides surprisingly accurate results wh...

The dynamics of a growing tungsten (W) nanoparticle (NP) cloud in a direct-current sputtering discharge were investigated with in-situ Light Extinction Spectroscopy (LES) and laser tomography techniques, as well as off-line electron microscopy and Raman spectroscopy techniques. This experimental work revealed the growth of a first generation of par...

This paper reports the work in progress to develop a multi-angle light scattering apparatus allowing routine characterization of liquid suspensions, of nanometer-sized particle and their aggregates, in freely exchangeable sample cells. The specificities of the proposed system consist in three points: the ellipticity of the illuminating beam, a dete...

The dynamics of a growing tungsten (W) nanoparticle (NP) cloud in a direct‐current sputtering discharge were investigated with in‐situ Light Extinction Spectroscopy (LES) and laser tomography techniques, as well as off‐line electron microscopy and Raman spectroscopy techniques. This experimental work revealed the growth of a first generation...

This talk summerizes the work done on the analyzes of the various phenomena that need to be accounted for in modeling the light-scattering properties of large spherical bubbles in the context of geometrical and physical optics approximations. Among these phenomena are interference occurring between higher-order rays, the Goos–Hänchen shift, the tun...

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...

poster

this study proposes a better understanding of the growth, the agglomeration phases and the spatial dynamics of a tungsten nanoparticle cloud created in direct-current argon glow sputtering discharge.

This paper reports the work in progress to develop a multi-angle light scattering apparatus allowing routine characterization of liquid suspensions, of nanometer-sized particle and their aggregates, in freely exchangeable sample cells. The specificities of the proposed system consist in three points: the ellipticity of the illuminating beam, a dete...

This paper considers various phenomena in modeling the light-scattering properties of bubbles in the context of geometrical and physical optics approximations (GOA & POA), opening up perspectives for the computationally efficient prediction of the optical properties of complex shaped bubbles as well as bubbly flows characterization.

This paper reports investigations on the experimental characterization of large prolate droplets from the analysis of their light scattering patterns in the first rainbow angle region. Inversions, performed with an advanced vectorial complex ray model, clearly demonstrate the necessity to account for extremely small ellipticities.

This paper reports the work in progress to develop a multi-angle light scattering apparatus allowing routine characterization of liquid suspensions, of nanometer-sized particle and their aggregates, in freely exchangeable sample cells. The specificities of the proposed system consist in three points: the ellipticity of the illuminating beam, a dete...

The growth and the dynamics of a tungsten nanoparticle cloud were investigated in a direct-current low pressure argon glow discharge. Real-time analyses of the dust particle size and number concentration were performed in-situ by light extinction spectrometry, while spatial dynamics of the cloud was investigated with the laser light-sheet scatterin...

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.

In this article, a detailed introduction of the light extinction spectrometry (LES)diagnostics is given. LES allows the directin situmeasurement of the particle sizedistribution and absolute concentration of dust clouds levitating in plasmas. Usinga relatively simple and compact experimental set-up, the dust cloud parameters canbe recovered with a...

Organic Photo Sensor (OPS) technology allows printing on conformable plastic-like substrates complex-shaped, arbitrarily-sized and pre-aligned photosensitive elements. This article reports, to the best of our knowledge, the first investigation to implement this emerging technology for Multi-Angle Light Scattering (MALS) characterization of nano- an...

A review of a recent contributions in the modeling and the optical characterization of droplets, bubbles and nanoparticles.