The anti-suck-back ability of five new high-speed air turbine handpiece models was evaluated in this study. First, suck-back pressure with water displacement within a glass tube was measured. Next, under three different conditions, how many on-off times it takes before fluorescent stains became visible on a piece of gauze at the exhaust vent was counted and the presence of fluorescent stains on...

The synthesis of three-dimensional (3-D) assemblies of zirconia nanocrystals via the shape-preserving reactive conversion of biologically reproducible, silica-based microtemplates (diatom microshells) is demonstrated for the first time. Silica diatom microshells were first converted into magnesia replicas via an oxidation–reduction displacement reaction with magnesium gas. The magnesia replicas...

In this paper, we are interested in the finite volume approximation of a system describing miscible displacement in porous media. This system is made of two coupled equations: an anisotropic diffusion equation on the pressure and a convection-diffusion-dispersion equation on the concentration of invading fluid. The anisotropic diffusion operators in both equations require a special care while d...

We derive rigorously homogenized models for the displacement of one compressible miscible fluid by another in fractured porous media. We denote by the characteristic size of the heterogeneity in the medium. A parameter α ∈ [0, 1] characterizes the cracking degree of the rock. We carefully define an adapted microscopic model which is scaled by appropriate powers of . We then study its limit as →...