Macroscopic behavior of bidisperse suspensions of noncolloidal particles in yield stress fluids

We study both experimentally and theoretically the rheological behavior of isotropic bidisperse suspensions of noncolloidal particles in yield stress fluids. We focus on materials in which noncolloidal particles interact with the suspending fluid only through hydrodynamical interactions. We observe that both the elastic modulus and yield stress of bidisperse suspensions are lower than those of monodisperse suspensions of same solid volume fraction. Moreover, we show that the dimensionless yield stress of such suspensions is linked to their dimensionless elastic modulus and to their solid volume fraction through the simple equation of Chateau et al.[J. rheol. 52, 489-506 (2008)]. We also show that the effect of the particle size heterogeneity can be described by means of a packing model developed to estimate random loose packing of assemblies of dry particles. All these observations finally allow us to propose simple closed form estimates for both the elastic modulus and the yield stress of bidisperse suspensions: while the elastic modulus is a function of the reduced volume fraction $\phi/\phi_m$ only, where $\phi_m$ is the estimated random loose packing, the yield stress is a function of both the volume fraction $\phi$ and the reduced volume fraction

Influence of water vapour on the propagation speed and mean energy of an atmospheric non-equilibrium diffuse discharge in air

We report results on the influence of humidity on the propagation and the energy of a pin-to-plane nanosecond pulse discharge at atmospheric pressure. Water vapour only impacts discharges in saturated gas mixtures, for which propagation is first slowed down, but accelerates faster than usual close to the plane. Energy is unchange

Accelerating functional gene discovery in osteoarthritis

Osteoarthritis causes debilitating pain and disability, resulting in a considerable socioeconomic burden, yet no drugs are available that prevent disease onset or progression. Here, we develop, validate and use rapid-throughput imaging techniques to identify abnormal joint phenotypes in randomly selected mutant mice generated by the International Knockout Mouse Consortium. We identify 14 genes with functional involvement in osteoarthritis pathogenesis, including the homeobox gene Pitx1, and functionally characterize 6 candidate human osteoarthritis genes in mouse models. We demonstrate sensitivity of the methods by identifying age-related degenerative joint damage in wild-type mice. Finally, we phenotype previously generated mutant mice with an osteoarthritis-associated polymorphism in the Dio2 gene by CRISPR/Cas9 genome editing and demonstrate a protective role in disease onset with public health implications. We hope this expanding resource of mutant mice will accelerate functional gene discovery in osteoarthritis and offer drug discovery opportunities for this common, incapacitating chronic disease

Experimental study of the effect of the reactive gas injection geometry in atmospheric pressure inductive plasma torch on the chemical efficiency.

International audienceThe effect of the reactant gas injection mode into inductively coupled plasma has been investigated, through the volatilization reaction of a graphite target submitted to argon-oxygen plasma. A graphite disk is positioned at different distances under the plasma torch. The addition of oxygen to the plasma results in a carving, of the graphite surface, which depend on the injection mode: into the outer, the intermediate or the inner argon flow. The mass losses permit to evaluate the global efficiency. The profile of the graphite surface at the end of the operation reflects the distribution of the reactive species. The graphite is heated by induction in order to stabilise its temperature between 1500 and 1800 K and to obtain stable reaction conditions. The most efficient, from the point of view of the reactive gas, consists in addition to the inner flow. The most homogeneous volatilization is obtained when the reactant is added to the outer flow

Odorous volatile compounds conversion by electro-ceramic barrier discharge

International audienceDecomposition of butyric acid and dimethyl sulphide diluted in dry air is studied in coaxial cylindrical geometry of Electro-ceramic Barrier Discharge (EBD). Removal rates are measured for different initial concentrations and electrical parameters. By products are identified using FTIR spectroscopy and PTR-MS diagnostic

Real-time analysis of toluene removal in dry air by a dielectric barrier discharge using proton transfer reaction mass spectrometry

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