Dominique ELZO - Academia.edu (original) (raw)
Papers by Dominique ELZO
Journal of Membrane Science, 1996
A fundamental study of particle detachment of micron-sized glass particles from a model membrane ... more A fundamental study of particle detachment of micron-sized glass particles from a model membrane surface is made. The model membrane surface consisted of a cellulose diacetate fihn which is the polymeric constituent of the hollow fibre membranes used in industrial water treatment. This experimental study aims to analyse the factors leading to the retention of particles on these membranes. We used a hydrodynamic method in which the release of deposited particles was measured under the action of fluid llow. The hydrodynamic force is calculated under well defined hydrodynamic conditions and related to the total adhesive fi~rce acting on the particle. We studied the influence of several factors such as, pH, solution salinity, and the effects of adsorbed polymer or non-ionic surfactant on the particles. In the absence of organic solutes adsorbed on the particles, the magnitude of the particle-membrane interaction depended on the pH and the salinity of the aqueous medium, as predicted by the DLVO theory. When adsorbed polymer layers are coated on the surface of the particles, the adhesive force between the particles and the surface was found to be significantly greater than that for bare particles. This contrasted to the decrease in adhesion force observed for particle coated with non-ionic surfactant.
Journal of Physics: Conference Series, 2012
We developed an atomizer nozzle equipping a medical device used for airborne disinfection of medi... more We developed an atomizer nozzle equipping a medical device used for airborne disinfection of medical rooms. The diffusion technology of the equipment is based on the spraying of fine liquid droplets of disinfectant into the volume to be treated. The liquid phase is expulsed thanks to an air assist atomizer we designed, which originality comes from the geometry we give to the throat of the micro-venturi, inner part of the atomizer nozzle. The micro-venturi throat is deviated of angle of 4°and will permit a homogeneous diffusion. We computed three dimensional numerical calculations of the inner compressible turbulent air flow through the atomizer we designed and compared the results obtained with the ones computed for a symmetrical atomizer. The modeling was done with the CFD codes STARCCM+ and Fluent, choosing the k-omega turbulent model. The modeling has been validated especially by one dimensional analytical calculations and experimental measurements of the mean axial velocity and mass flow rate circulating through the atomizer. Three dimensional numerical calculations show the vertical deviation of the flow at throat level and swirl effect generated by the deviated inner throat of the micro-venturi. These calculations allowed understanding the nature of the spray observed in experimental conditions, and the advantages to use a deviated micro-venturi throat. Indeed, micro bacteriological tests showed that the quality and the effectiveness of the diffusion are enhanced in comparison to equipments with a symmetrical micro-venturi.
2017 23rd International Workshop on Thermal Investigations of ICs and Systems (THERMINIC), 2017
This work presents results obtained on the characterization of hydrodynamics and thermal transfer... more This work presents results obtained on the characterization of hydrodynamics and thermal transfer coupling of a Dual piezoelectric Cool Jet (DCJ). The convective heat transfer coefficient was evaluated through experimental tests and numerical studies. The manipulation applied to the thermal study was implemented with measurements of power heat and temperatures along a heating plate. The objective is to be able to estimate the impact of the DCJ device on the heat transfer coefficient. In order to understand the different thermo-fluidphenomena, the numerical study was also carried out through the STAR-CCM+ CFD software. The high vibration frequency of piezoelectric membranes, which corresponds to 175 Hz, induced a very little time step to follow the produced air flow. Consequently, the main challenge in numerical simulation was the scale up of flow movements at an acceptable time characterization for the coupling between hydrodynamics and thermal transfer.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1998
Cross-flow microfiltration experiments were performed with 0.5 mm silica particles using an inorg... more Cross-flow microfiltration experiments were performed with 0.5 mm silica particles using an inorganic membrane of 0.2 mm pore size. We analysed how several physico-chemical factors, such as solution pH, salt concentration, and valency of the salt influenced permeate flux and fouling tendencies. The electrostatic properties of silica particles (feed suspension) and a-alumina particles (active layer of the membrane) were characterised by performing zeta potential measurements. It was found that the permeate flux is dependent on the surface charge of the suspended particles and possibly dependent on the surface charge of the membrane. High permeate fluxes are obtained at high pH and low salt concentration. Under these circumstances the repulsion between the silica particles is strong. In contrast, low filtration fluxes are measured at high salt concentration, low pH, and with a CaCl 2 electrolyte, i.e. when the surface charges are weak and in the presence of specific cations. The net energy of interaction between the charged surfaces involved in the microfiltration process was calculated using the DLVO theory. This gave qualitative arguments for the explanation of the observed changes in the permeate flux.
Colloids and Surfaces A-physicochemical and Engineering Aspects, 1998
The conditions necessary for the formation of a reversible cake layer during crossflow microfiltr... more The conditions necessary for the formation of a reversible cake layer during crossflow microfiltration were studied both experimentally and theoretically. Crossflow microfiltration experiments were performed with suspensions of silica particles with a narrow size distribution. The steady-state flux was first measured at a low transmembrane pressure (TMP), then at increased TMP, and again at the original low TMP. The cake-layer
Nous avons mene une etude experimentale qui consiste a mesurer la force qui agit sur une particul... more Nous avons mene une etude experimentale qui consiste a mesurer la force qui agit sur une particule spherique deposee sur une surface plane en milieu liquide. L'estimation de la force d'adhesion particule/surface s'effectue au moyen d'une technique hydrodynamique d'arrachement des particules. Le principe de cette technique repose sur la mesure de la force hydrodynamique qui permet sous l'action d'un ecoulement laminaire de reentrainer les particules deposees sur la paroi d'une cellule a section rectangulaire. Le fluide utilise est de l'eau distillee ultrafiltree. Les particules sont des billes de silice d'un diametre compris entre dix et quarante microns. Nous avons analyse l'influence sur les mecanismes d'adhesion particule/surface de facteurs tels que la concentration en particules deposees sur la plaque, la salinite et le potentiel hydrogene de la solution, les effets de polymeres neutres ou de surfactant adsorbes a la surface des pa...
Double side cooling and wire-bondless interconnections are envisioned as ways to go for Electroni... more Double side cooling and wire-bondless interconnections are envisioned as ways to go for Electronic Power Modules. aPSI3D has developed an integrated approach for the design of such a power module. Prototypes have been manufactured and characterized in terms of electronics and thermo-fluidics. The parasitic self-inductance which involves the physical copper layers carrying the main current are significantly reduced, in agreement with previous simulations. An electro-thermal liquid cooled bench was fully developed by ICAM in order to extract the Power Module thermo-fluidic behavior. Thermal resistance are extracted and compared to simulations. During these characterizations, several material interfaces were identified as critical for the thermal behavior.
The conditions necessary for the formation of a reversible cake layer during crossflow microfiltr... more The conditions necessary for the formation of a reversible cake layer during crossflow microfiltration were studied both experimentally and theoretically. Crossflow microfiltration experiments were performed with suspensions of silica particles with a narrow size distribution. The steady-state flux was first measured at a low transmembrane pressure (TMP), then at increased TMP, and again at the original low TMP. The cake-layer thickness was measured indirectly using a light absorbance technique. The thickness of the cake layer increased with increased TMP. Upon decreasing the TMP, the cake-layer thickness either decreased (reversible cake), or stayed constant (irreversible cake). It was shown that irreversible cakes are formed when the silica particles have a relatively low charge, whereas reversible cakes are formed when the silica particles have a relatively high charge. The occurrence of irreversible cakes is unexpected, since approaching silica particles are reported to always repel each other. The irreversibility of the cakes was explained by the assumption that bridging between the particles can occur, causing the interparticle interaction to be attractive when the particles retreat. To explain the reversibility results quantitatively, a model was developed which links the physicochemical interaction forces of the silica particles to the permeate flux through the cake layer. A detailed description of the interaction forces of silica particles was given in order to feed this model with accurate parameters. A reversibility index was introduced which quantifies the amount of reversibility. Model calculations of the reversibility index were in excellent agreement with measurements.
Colloids and Surfaces a Physicochemical and Engineering Aspects, Jul 1, 1998
The conditions necessary for the formation of a reversible cake layer during crossflow microfiltr... more The conditions necessary for the formation of a reversible cake layer during crossflow microfiltration were studied both experimentally and theoretically. Crossflow microfiltration experiments were performed with suspensions of silica particles with a narrow size distribution. The steady-state flux was first measured at a low transmembrane pressure (TMP), then at increased TMP, and again at the original low TMP. The cake-layer thickness was measured indirectly using a light absorbance technique.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1998
The conditions necessary for the formation of a reversible cake layer during crossflow microfiltr... more The conditions necessary for the formation of a reversible cake layer during crossflow microfiltration were studied both experimentally and theoretically. Crossflow microfiltration experiments were performed with suspensions of silica particles with a narrow size distribution. The steady-state flux was first measured at a low transmembrane pressure (TMP), then at increased TMP, and again at the original low TMP. The cake-layer thickness was measured indirectly using a light absorbance technique.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1998
Cross-flow microfiltration experiments were performed with 0.5 mm silica particles using an inorg... more Cross-flow microfiltration experiments were performed with 0.5 mm silica particles using an inorganic membrane of 0.2 mm pore size. We analysed how several physico-chemical factors, such as solution pH, salt concentration, and valency of the salt influenced permeate flux and fouling tendencies. The electrostatic properties of silica particles (feed suspension) and a-alumina particles (active layer of the membrane) were characterised by performing zeta potential measurements. It was found that the permeate flux is dependent on the surface charge of the suspended particles and possibly dependent on the surface charge of the membrane. High permeate fluxes are obtained at high pH and low salt concentration. Under these circumstances the repulsion between the silica particles is strong. In contrast, low filtration fluxes are measured at high salt concentration, low pH, and with a CaCl 2 electrolyte, i.e. when the surface charges are weak and in the presence of specific cations. The net energy of interaction between the charged surfaces involved in the microfiltration process was calculated using the DLVO theory. This gave qualitative arguments for the explanation of the observed changes in the permeate flux.
The Canadian Journal of Chemical Engineering, 1998
L'objectif principal de ce travail est la caracterisation des effets produits par I'uti... more L'objectif principal de ce travail est la caracterisation des effets produits par I'utilisation de detergents commerciaux sur les proteines du lactoserum, dans le but de selectionner un detergent efficace pour le nettoyage des membranes inorg-aniques colmatees dans les procedes de ...
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1998
The conditions necessary for the formation of a reversible cake layer during crossflow microfiltr... more The conditions necessary for the formation of a reversible cake layer during crossflow microfiltration were studied both experimentally and theoretically. Crossflow microfiltration experiments were performed with suspensions of silica particles with a narrow size distribution. The steady-state flux was first measured at a low transmembrane pressure (TMP), then at increased TMP, and again at the original low TMP. The cake-layer thickness was measured indirectly using a light absorbance technique.
Journal of Membrane Science, 1996
A fundamental study of particle detachment of micron-sized glass particles from a model membrane ... more A fundamental study of particle detachment of micron-sized glass particles from a model membrane surface is made. The model membrane surface consisted of a cellulose diacetate fihn which is the polymeric constituent of the hollow fibre membranes used in industrial water treatment. This experimental study aims to analyse the factors leading to the retention of particles on these membranes. We used a hydrodynamic method in which the release of deposited particles was measured under the action of fluid llow. The hydrodynamic force is calculated under well defined hydrodynamic conditions and related to the total adhesive fi~rce acting on the particle. We studied the influence of several factors such as, pH, solution salinity, and the effects of adsorbed polymer or non-ionic surfactant on the particles. In the absence of organic solutes adsorbed on the particles, the magnitude of the particle-membrane interaction depended on the pH and the salinity of the aqueous medium, as predicted by the DLVO theory. When adsorbed polymer layers are coated on the surface of the particles, the adhesive force between the particles and the surface was found to be significantly greater than that for bare particles. This contrasted to the decrease in adhesion force observed for particle coated with non-ionic surfactant.
Journal of Physics: Conference Series, 2012
We developed an atomizer nozzle equipping a medical device used for airborne disinfection of medi... more We developed an atomizer nozzle equipping a medical device used for airborne disinfection of medical rooms. The diffusion technology of the equipment is based on the spraying of fine liquid droplets of disinfectant into the volume to be treated. The liquid phase is expulsed thanks to an air assist atomizer we designed, which originality comes from the geometry we give to the throat of the micro-venturi, inner part of the atomizer nozzle. The micro-venturi throat is deviated of angle of 4°and will permit a homogeneous diffusion. We computed three dimensional numerical calculations of the inner compressible turbulent air flow through the atomizer we designed and compared the results obtained with the ones computed for a symmetrical atomizer. The modeling was done with the CFD codes STARCCM+ and Fluent, choosing the k-omega turbulent model. The modeling has been validated especially by one dimensional analytical calculations and experimental measurements of the mean axial velocity and mass flow rate circulating through the atomizer. Three dimensional numerical calculations show the vertical deviation of the flow at throat level and swirl effect generated by the deviated inner throat of the micro-venturi. These calculations allowed understanding the nature of the spray observed in experimental conditions, and the advantages to use a deviated micro-venturi throat. Indeed, micro bacteriological tests showed that the quality and the effectiveness of the diffusion are enhanced in comparison to equipments with a symmetrical micro-venturi.
2017 23rd International Workshop on Thermal Investigations of ICs and Systems (THERMINIC), 2017
This work presents results obtained on the characterization of hydrodynamics and thermal transfer... more This work presents results obtained on the characterization of hydrodynamics and thermal transfer coupling of a Dual piezoelectric Cool Jet (DCJ). The convective heat transfer coefficient was evaluated through experimental tests and numerical studies. The manipulation applied to the thermal study was implemented with measurements of power heat and temperatures along a heating plate. The objective is to be able to estimate the impact of the DCJ device on the heat transfer coefficient. In order to understand the different thermo-fluidphenomena, the numerical study was also carried out through the STAR-CCM+ CFD software. The high vibration frequency of piezoelectric membranes, which corresponds to 175 Hz, induced a very little time step to follow the produced air flow. Consequently, the main challenge in numerical simulation was the scale up of flow movements at an acceptable time characterization for the coupling between hydrodynamics and thermal transfer.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1998
Cross-flow microfiltration experiments were performed with 0.5 mm silica particles using an inorg... more Cross-flow microfiltration experiments were performed with 0.5 mm silica particles using an inorganic membrane of 0.2 mm pore size. We analysed how several physico-chemical factors, such as solution pH, salt concentration, and valency of the salt influenced permeate flux and fouling tendencies. The electrostatic properties of silica particles (feed suspension) and a-alumina particles (active layer of the membrane) were characterised by performing zeta potential measurements. It was found that the permeate flux is dependent on the surface charge of the suspended particles and possibly dependent on the surface charge of the membrane. High permeate fluxes are obtained at high pH and low salt concentration. Under these circumstances the repulsion between the silica particles is strong. In contrast, low filtration fluxes are measured at high salt concentration, low pH, and with a CaCl 2 electrolyte, i.e. when the surface charges are weak and in the presence of specific cations. The net energy of interaction between the charged surfaces involved in the microfiltration process was calculated using the DLVO theory. This gave qualitative arguments for the explanation of the observed changes in the permeate flux.
Colloids and Surfaces A-physicochemical and Engineering Aspects, 1998
The conditions necessary for the formation of a reversible cake layer during crossflow microfiltr... more The conditions necessary for the formation of a reversible cake layer during crossflow microfiltration were studied both experimentally and theoretically. Crossflow microfiltration experiments were performed with suspensions of silica particles with a narrow size distribution. The steady-state flux was first measured at a low transmembrane pressure (TMP), then at increased TMP, and again at the original low TMP. The cake-layer
Nous avons mene une etude experimentale qui consiste a mesurer la force qui agit sur une particul... more Nous avons mene une etude experimentale qui consiste a mesurer la force qui agit sur une particule spherique deposee sur une surface plane en milieu liquide. L'estimation de la force d'adhesion particule/surface s'effectue au moyen d'une technique hydrodynamique d'arrachement des particules. Le principe de cette technique repose sur la mesure de la force hydrodynamique qui permet sous l'action d'un ecoulement laminaire de reentrainer les particules deposees sur la paroi d'une cellule a section rectangulaire. Le fluide utilise est de l'eau distillee ultrafiltree. Les particules sont des billes de silice d'un diametre compris entre dix et quarante microns. Nous avons analyse l'influence sur les mecanismes d'adhesion particule/surface de facteurs tels que la concentration en particules deposees sur la plaque, la salinite et le potentiel hydrogene de la solution, les effets de polymeres neutres ou de surfactant adsorbes a la surface des pa...
Double side cooling and wire-bondless interconnections are envisioned as ways to go for Electroni... more Double side cooling and wire-bondless interconnections are envisioned as ways to go for Electronic Power Modules. aPSI3D has developed an integrated approach for the design of such a power module. Prototypes have been manufactured and characterized in terms of electronics and thermo-fluidics. The parasitic self-inductance which involves the physical copper layers carrying the main current are significantly reduced, in agreement with previous simulations. An electro-thermal liquid cooled bench was fully developed by ICAM in order to extract the Power Module thermo-fluidic behavior. Thermal resistance are extracted and compared to simulations. During these characterizations, several material interfaces were identified as critical for the thermal behavior.
The conditions necessary for the formation of a reversible cake layer during crossflow microfiltr... more The conditions necessary for the formation of a reversible cake layer during crossflow microfiltration were studied both experimentally and theoretically. Crossflow microfiltration experiments were performed with suspensions of silica particles with a narrow size distribution. The steady-state flux was first measured at a low transmembrane pressure (TMP), then at increased TMP, and again at the original low TMP. The cake-layer thickness was measured indirectly using a light absorbance technique. The thickness of the cake layer increased with increased TMP. Upon decreasing the TMP, the cake-layer thickness either decreased (reversible cake), or stayed constant (irreversible cake). It was shown that irreversible cakes are formed when the silica particles have a relatively low charge, whereas reversible cakes are formed when the silica particles have a relatively high charge. The occurrence of irreversible cakes is unexpected, since approaching silica particles are reported to always repel each other. The irreversibility of the cakes was explained by the assumption that bridging between the particles can occur, causing the interparticle interaction to be attractive when the particles retreat. To explain the reversibility results quantitatively, a model was developed which links the physicochemical interaction forces of the silica particles to the permeate flux through the cake layer. A detailed description of the interaction forces of silica particles was given in order to feed this model with accurate parameters. A reversibility index was introduced which quantifies the amount of reversibility. Model calculations of the reversibility index were in excellent agreement with measurements.
Colloids and Surfaces a Physicochemical and Engineering Aspects, Jul 1, 1998
The conditions necessary for the formation of a reversible cake layer during crossflow microfiltr... more The conditions necessary for the formation of a reversible cake layer during crossflow microfiltration were studied both experimentally and theoretically. Crossflow microfiltration experiments were performed with suspensions of silica particles with a narrow size distribution. The steady-state flux was first measured at a low transmembrane pressure (TMP), then at increased TMP, and again at the original low TMP. The cake-layer thickness was measured indirectly using a light absorbance technique.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1998
The conditions necessary for the formation of a reversible cake layer during crossflow microfiltr... more The conditions necessary for the formation of a reversible cake layer during crossflow microfiltration were studied both experimentally and theoretically. Crossflow microfiltration experiments were performed with suspensions of silica particles with a narrow size distribution. The steady-state flux was first measured at a low transmembrane pressure (TMP), then at increased TMP, and again at the original low TMP. The cake-layer thickness was measured indirectly using a light absorbance technique.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1998
Cross-flow microfiltration experiments were performed with 0.5 mm silica particles using an inorg... more Cross-flow microfiltration experiments were performed with 0.5 mm silica particles using an inorganic membrane of 0.2 mm pore size. We analysed how several physico-chemical factors, such as solution pH, salt concentration, and valency of the salt influenced permeate flux and fouling tendencies. The electrostatic properties of silica particles (feed suspension) and a-alumina particles (active layer of the membrane) were characterised by performing zeta potential measurements. It was found that the permeate flux is dependent on the surface charge of the suspended particles and possibly dependent on the surface charge of the membrane. High permeate fluxes are obtained at high pH and low salt concentration. Under these circumstances the repulsion between the silica particles is strong. In contrast, low filtration fluxes are measured at high salt concentration, low pH, and with a CaCl 2 electrolyte, i.e. when the surface charges are weak and in the presence of specific cations. The net energy of interaction between the charged surfaces involved in the microfiltration process was calculated using the DLVO theory. This gave qualitative arguments for the explanation of the observed changes in the permeate flux.
The Canadian Journal of Chemical Engineering, 1998
L'objectif principal de ce travail est la caracterisation des effets produits par I'uti... more L'objectif principal de ce travail est la caracterisation des effets produits par I'utilisation de detergents commerciaux sur les proteines du lactoserum, dans le but de selectionner un detergent efficace pour le nettoyage des membranes inorg-aniques colmatees dans les procedes de ...
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1998
The conditions necessary for the formation of a reversible cake layer during crossflow microfiltr... more The conditions necessary for the formation of a reversible cake layer during crossflow microfiltration were studied both experimentally and theoretically. Crossflow microfiltration experiments were performed with suspensions of silica particles with a narrow size distribution. The steady-state flux was first measured at a low transmembrane pressure (TMP), then at increased TMP, and again at the original low TMP. The cake-layer thickness was measured indirectly using a light absorbance technique.