On the Synthesis of Pyrrolobenzo[<Emphasis Type="Italic">b</Emphasis>]thieno[1,4]diazepines

Summary. 2-Amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile was converted into the corresponding 2-(pyrrol-1-yl) derivative, followed by reduction of the latter compound into the corresponding amine. This amine and its acyl, aroyl, and arylidene derivatives were used as synthons in the synthesis of several title compounds.     

Multinuclear NMR study of the structure and micro-dynamics of counterions and water molecules within clay colloids

Multinuclear NMR spectroscopy, relaxation and diffusion measurements were used recently to extract dynamical information on the long-time mobility of the water molecules and the neutralizing counterions condensed within the electrostatic well in the vicinity of the basal surface of clay particles. Multi-scale numerical modeling was used to interpret the NMR relaxation measurements and illustrate the interdependency between the solvent and ionic mobility and the organization of the anisotropic clay particles within the colloidal dispersions.     

Investigation on laser brazing AA6056 Al alloy to XC18 low-carbon steel

Based on the studies of influence of YAG laser heating conditions for Al alloy melt and steel on wettability,the mechanics of the laser overlap braze welding of 6056 Al and XC18 steel sheet has been investigated.Under the temperature range which is above the melting point of the Al alloy and below the melting point of the steel, two dissimilar metals can be joined by means of laser braze welding. There is no crack observed in the joining area, i.e. Al-Fe intermetallic phase (Fe3Al/FeAl/FeAl3/Fe2Al5) layer formed by solution and diffusion between liquid-solid interface. The temperature range can be defined as the process temperatures of laser braze welding of Al-Fe materials. Selecting a higher laser heating temperature can improve the wettability of Al melt to steel surface, but the intermetallic phase layer is also thicker. When the laser heating temperature is so high that the joining surface of steel is melted, there is a crack trend in the joining area.     

Determination of self-diffusion coefficients from conductivity measurements in perfluorinated ionomer membranes

Values of the self-diffusion coefficients for sodium and cesium ions in 1200 Equivalent Weight Nafion® membranes have been deduced from conductivity measurements, assuming the validity of the Einstein relation between self-diffusion coefficient and absolute ionic mobility. Results obtained are in good agreement with previously published data obtained from direct measurements.     

Justification of the kinematic assumptions for thin-walled rods with shallow profile

In this Note we present a justification of the kinematic assumptions for thin-walled rods with shallow profile. These assumptions are fundamental to writing the one-dimensional equilibrium equations for such structures. The obtained kinematics are different from the Vlassov case, which is only valid for strongly curved profiles. They are also different from the that classically used in shell theory. The justification given in this Note is based on an asymptotic approach. To cite this article: L. Grillet et al., C. R. Mecanique 333 (2005).     

Squeeze flow of Bingham fluids under slip with friction boundary condition

This paper develops a theoretical analysis of a Bingham fluid in slipping squeeze flow. The flow field decomposition consists in combining a central extensional flow zone in the plane of symmetry and shear flow zones near the plates. It is also considered that the slipping zone is located around a central sticking zone as previously shown from experiments. It is assumed that the shear stress at the plates is constant in the slipping zone and equals a fixed friction yield value. The squeeze force required to compress a Bingham fluid under the slipping behaviour as well as the radial evolution of the transition point between both sticking and slipping zones are finally determined.