Michelin (Switzerland)

We successfully demonstrated and reported the highest solar-to-hydrogen efficiency with crystalline silicon cells and Earth-abundant electrocatalysts under unconcentrated solar radiation. The combination of hetero-junction silicon cells and a 3D printed Platinum/Iridium-Oxide electrolyzer has been proven to work continuously for more than 24 hours in neutral environment, with a stable 13.5% solar-to-fuel efficiency. Since the hydrogen economy is expected to expand to a global scale, we demonstrated the same efficiency with an Earth-abundant electrolyzer based on Nickel in a basic medium. In both cases, electrolyzer and photovoltaic cells have been specifically sized for their characteristic curves to intersect at a stable operating point. This is foreseen to guarantee constant operation over the device lifetime without performance degradation. The next step is to lower the production cost of hydrogen by making use of medium range solar concentration. It permits to limit the photoabsorbing area, shown to be the cost-driver component. We have recently modeled a self-tracking solar concentrator, able to capture sunlight within the acceptance angle range +/-45°, implementing 3 custom lenses. The design allows a fully static device, avoiding the external tracker that was necessary in a previously demonstrated +/-16° angular range concentrator. We will show two self-tracking methods. The first one relies on thermal expansion whereas the second method relies on microfluidics

The California poppy (Eschscholzia californica Cham.) contains a variety of natural compounds including several alkaloids found exclusively in this plant. Because of the sedative, anxiolytic, and analgesic effects, this herb is currently sold in pharmacies in many countries. However, our understanding of these biological effects at the molecular level is still lacking. Alkaloids detected in E. californica could be hypothesized to act at GABAA receptors, which are widely expressed in the brain mainly at the inhibitory interneurons. Electrophysiological studies on a recombinant α1β2γ2 GABAA receptor showed no effect of N-methyllaurotetanine at concentrations lower than 30 μM. However, (S)-reticuline behaved as positive allosteric modulator at the α3, α5, and α6 isoforms of GABAA receptors. The depressant properties of aerial parts of E. californica are assigned to chloride-current modulation by (S)-reticuline at the α3β2γ2 and α5β2γ2 GABAA receptors. Interestingly, α1, α3, and α5 were not significantly affected by (R)-reticuline, 1,2-tetrahydroreticuline, codeine, and morphine—suspected (S)-reticuline metabolites in the rodent brain.

Dow and Rosen’s work in 1965 formed an intellectual framework for compressive strength of unidirectional composites. Compressive strength was explained in terms of micro-buckling, in which filaments are beams on an elastic foundation. While groundbreaking, the discrepancy between model predictions and observed compressive strength is well known. This study builds on Dow and Rosen’s model specifically with respect to the dominant shear mode instability. A new method that accounts for matrix thermal residual strain, matrix compressive and shear stresses, with associated reductions in tangent modulus due to matrix non-linearity, is proposed. The method is validated using a specific test case, which is conducted to precisely account for microscopic fiber alignment and matrix non-linearity. Accordingly, a method of measuring and accounting for a continuum of fiber misalignment is developed. Predictions are compared to literature values, with variations in fiber modulus, matrix modulus, and volume fraction. Good agreement is shown, both in terms of trend and magnitude. The approach successfully preserves initial in-plane shear stiffness, while showing that in-plane shear stiffness decreases significantly as compressive stress increases.

Au centre de cet article, l’idée que les prostituées « indigènes », parce qu’elles se trouvent au croisement de l’ordre et du désordre, de la conformité et de la déviance, du permis et de l’interdit, sont des êtres de l’hybridation. Bien que sous contrôle d’un système réglementariste extrêmement répressif, les prostituées « indigènes » ne se contentent pas, en effet, de se situer dans un « entre deux » mais proposent une synthèse inédite qui touche l’ensemble de leur vie quotidienne : leurs pratiques religieuses, médicales, corporelles, sexuelles, linguistiques… Ce faisant, elles donnent à voir leur extraordinaire capacité d’adaptation mais aussi la richesse et la complexité d’une société « en mouvement » qui se recompose au contact de la colonisation.