Denis Mazuyer

Bio: Denis Mazuyer is an academic researcher from École centrale de Lyon. The author has contributed to research in topics: Lubrication & Lubricant. The author has an hindex of 21, co-authored 80 publications receiving 1476 citations. Previous affiliations of Denis Mazuyer include Centre national de la recherche scientifique.

Experimental Evidence for a Large Slip Effect at a Nonwetting Fluid−Solid Interface

Abstract: It is shown that the flow of a simple Newtonian liquid near a hard wall can be affected by the chemical nature of this wall. We have studied with a surface force apparatus (SFA) the hydrodynamic force between a sphere and a plane immersed in glycerol. The drainage of the thin film is different on a hydrophobic plane and a hydrophilic one. This effect can be interpreted, when the film is not too thin, by the existence of a slipping velocity at the boundary between the liquid and the hydrophobic solid. The slipping length is about 65 times the glycerol molecular size.

Effects of Grease Composition and Structure on Film Thickness in Rolling Contact

Abstract: The aim of this work is to show the correlation between the tribological behavior of grease and its composition and structure. A tribological investigation was conducted on various lubricants. The following parameters were varied: base oil, soap and presence of additives. To ensure efficient control of grease composition, greases containing the same type of soap were manufactured from the same concentrated soap sample. Film thickness measurements showed that the thickener microstructure (revealed by TEM observations) is not the determining factor for the formation of a thick lubricant film, i.e. a film following EHL equations. Nevertheless, the soap - base oil interaction is an essential parameter. The composition of a grease influences oil bleeding, mechanical stability, and rheological behavior. The elastic modulus G' seems to be the only parameter directly linked to tribological behavior. Greases with low G' have a greater capacity to form a thick EHD film compared to greases with large G'.

Microfluidics: Fluid physics at the nanoliter scale

Abstract: Microfabricated integrated circuits revolutionized computation by vastly reducing the space, labor, and time required for calculations. Microfluidic systems hold similar promise for the large-scale automation of chemistry and biology, suggesting the possibility of numerous experiments performed rapidly and in parallel, while consuming little reagent. While it is too early to tell whether such a vision will be realized, significant progress has been achieved, and various applications of significant scientific and practical interest have been developed. Here a review of the physics of small volumes (nanoliters) of fluids is presented, as parametrized by a series of dimensionless numbers expressing the relative importance of various physical phenomena. Specifically, this review explores the Reynolds number Re, addressing inertial effects; the Peclet number Pe, which concerns convective and diffusive transport; the capillary number Ca expressing the importance of interfacial tension; the Deborah, Weissenberg, and elasticity numbers De, Wi, and El, describing elastic effects due to deformable microstructural elements like polymers; the Grashof and Rayleigh numbers Gr and Ra, describing density-driven flows; and the Knudsen number, describing the importance of noncontinuum molecular effects. Furthermore, the long-range nature of viscous flows and the small device dimensions inherent in microfluidics mean that the influence of boundaries is typically significant. A variety of strategies have been developed to manipulate fluids by exploiting boundary effects; among these are electrokinetic effects, acoustic streaming, and fluid-structure interactions. The goal is to describe the physics behind the rich variety of fluid phenomena occurring on the nanoliter scale using simple scaling arguments, with the hopes of developing an intuitive sense for this occasionally counterintuitive world.

Fast Mass Transport Through Sub-2-Nanometer Carbon Nanotubes

Abstract: We report gas and water flow measurements through microfabricated membranes in which aligned carbon nanotubes with diameters of less than 2 nanometers serve as pores. The measured gas flow exceeds predictions of the Knudsen diffusion model by more than an order of magnitude. The measured water flow exceeds values calculated from continuum hydrodynamics models by more than three orders of magnitude and is comparable to flow rates extrapolated from molecular dynamics simulations. The gas and water permeabilities of these nanotube-based membranes are several orders of magnitude higher than those of commercial polycarbonate membranes, despite having pore sizes an order of magnitude smaller. These membranes enable fundamental studies of mass transport in confined environments, as well as more energy-efficient nanoscale filtration.

Environmental applications of carbon-based nanomaterials.

Abstract: The unique and tunable properties of carbon-based nanomaterials enable new technologies for identifying and addressing environmental challenges. This review critically assesses the contributions of carbon-based nanomaterials to a broad range of environmental applications: sorbents, high-flux membranes, depth filters, antimicrobial agents, environmental sensors, renewable energy technologies, and pollution prevention strategies. In linking technological advance back to the physical, chemical, and electronic properties of carbonaceous nanomaterials, this article also outlines future opportunities for nanomaterial application in environmental systems.

Slip on Superhydrophobic Surfaces

Abstract: This review discusses the use of the combination of surface roughness and hydrophobicity for engineering large slip at the fluid-solid interface. These superhydrophobic surfaces were initially inspired by the unique water-repellent properties of the lotus leaf and can be employed to produce drag reduction in both laminar and turbulent flows, enhance mixing in laminar flows, and amplify diffusion-osmotic flows. We review the current state of experiments, simulations, and theory of flow past superhydrophobic surfaces. In addition, the designs and limitations of these surfaces are discussed, with an eye toward implementing these surfaces in a wide range of applications.