Using high pressure small angle X-ray scattering (HP-SAXS), we have studied monoolein (MO) mesophases at 18 wt% hydration in the presence of 10 nm silica nanoparticles (NPs) at NP-lipid number ratios (ν) of 1 × 10(-6), 1 × 10(-5) and 1 × 10(-4) over the pressure range 1-2700 bar and temperature range 20-60 °C. In the absence of the silica NPs, the pressure-temperature (p-T) phase diagram of monoolein exhibited inverse bicontinuous cubic gyroid (Q), lamellar alpha (Lα), and lamellar crystalline (Lc) phases. The addition of the NPs significantly altered the p-T phase diagram, changing the pressure (p) and the temperature (T) at which the transitions between these mesophases occurred. In particular, a strong NP concentration effect on the mesophase behaviour was observed. At low NP concentration, the p-T region pervaded by the Q phase and the Lα-Q mixture increased, and we attribute this behaviour to the NPs forming clusters at the mesophase domain boundaries, encouraging transition to the mesophase with a higher curvature. At high NP concentrations, the Q phase was no longer observed in the p-T phase diagram. Instead, it was dominated by the lamellar (L) phases until the transition to a fluid isotropic (FI) phase at 60 °C at low pressure. We speculate that NPs formed aggregates with a "chain of pearls" structure at the mesophase domain boundaries, hindering transitions to the mesophases with higher curvatures. These observations were supported by small angle neutron scattering (SANS) and scanning electron microscopy (SEM). Our results have implications to nanocomposite materials and nanoparticle cellular entry where the interactions between NPs and organised lipid structures are an important consideration.

Sommaire 1. INTRODUCTION. 2. BUTS DE LA PRÉSENTE ENQUÊTE. 3. CONDITIONS DE FORMATION DE VORTEX. 3.1. Introduction. 3.2. Variation des conditions hydrauliques. 3.3. Variation des formes géométriques. 4. AUTRES ANOMALIES n'ÉCOULEMENT. 4.1. Introduction. 4.2. Torche tourbillonnaire sous la tulipe de la prise. 4.3. Bulles et torches, chambre d'aspiration de la pompe de circulation de la centrale des Ansereuilles. 5. DISPOSITIFS ANTI-VORTEX. 5.1. Introduction. 5.2. Dispositifs anti-vortex. 5.3. Autre dispositif anti-vortex : le dispositif de grilles latérales en métal déployé. 6. SIMILITUDE DES VORTEX. 6.1. Remarques préliminaires. 6.2. Principaux critères. 6.3. Impossibilité de la réalisation d'une similitude complète. 6.4. Similitudes proposées. 6.5. Principaux résultats obtenus au Centre d'Essais et Recherches de Chatou sur la similitude des vortex. • Electricité de France.

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de la Suppression des vortex dans les chambres d' aspi ration des pompes de circulation centrale thermique de Creil Saint-Leu Eliminating vortices ln the circulation pump suction chamber of the Creil Saint-Leu thermal power station PAR ,J. LABETOUI..