Estimacion de la Orientacion: aplicacion a un mini-helicoptero con cuatro rotores

18-20 October 200

Insertion of indigo molecules in the sepiolite structure as evidenced by H-1-Si-29 heteronuclear correlation spectroscopy

International audienceDespite the numerous studies of the famous indigo-based pigment Maya Blue, there are still many questions regarding the elucidation of its structure. Here, two-dimensional (2D) H-1-Si-29 heteronuclear correlation (HETCOR) spectroscopy with frequency-switched Lee-Goldburg (FSLG) homonuclear decoupling is applied to sepiolite and sepiolite-indigo complexes. Owing to the high resolution in the H-1 dimension of the 2D H-1-Si-29 HETCOR spectrum obtained by FSLG homonuclear decoupling, the assignment of the Si-29 cross-polarization magic-angle spinning (CPMAS) spectrum of sepiolite is clearly confirmed. Moreover, 2D H-1-Si-29 FSLG-HETCOR spectroscopy gives the first direct evidence that some indigo molecules are inserted in the sepiolite structure whereas no interaction between indigo and the external side surface (silanol groups) is observed in the Si-29 CPMAS spectra. These results are consistent with the fact that indigo molecules interact with water coordinated to magnesium and suggest that Maya Blue made from sepiolite is not a surface complex

Flywheel energy storage systems in hybrid and distributed electricity generation

International audienceIn this article, we will demonstrate the benefit of the electromechanical storage of energy over long operating cycles (with time constants ranging from several minutes to a few hours), within the scope of decentralized electrical energy production. Both the principle and technology of the primary components used in an electromechanical accumulator will be presented herein. A number of well-known examples of systems will be shown in order to derive a summary state-of-the-art. We will then proceed by providing the example of a prototype developed at the SATIE Laboratory in the aim of designing a stationary accumulator for a domestic application requiring power on the order of one kilowatt

The incorporation of indigo molecules in sepiolite tunnels

International audienceEvidence for access of molecules the size of acetone or pyridine to the intracrystalline tunnels of nanofibre clay (sepiolite) has indicated formation of a new type of organic-inorganic nanocomposites. However, the introduction of larger molecules has been a recurring problem. It is now agreed that for indigo, the molecules are located on the external surface and at the ends of the fibres, thus blocking access to internal tunnels. We claim, however, that it is possible for indigo molecules to access the internal channels of sepiolite. FTIR and XRD analyses have provided evidence for folding of the sepiolite structure preheated at high temperature (above 350°C). By comparison, we have shown that for indigo/sepiolite mixtures treated in the same conditions, no change in the crystalline structure of the sepiolite is observed, and that blue samples, related to Maya blue, with indigo molecules incorporated deeply enough into sepiolite to prevent folding of the tunnels, can be obtained. NMR, FTIR and thermal analysis confirm the interaction of indigo with the water coordinated to magnesium(II) and located inside the internal and external channels of sepiolite. Two other hypotheses are excluded; we show both that zeolitic water is not blocked in the tunnels by indigo, and that if thermal decomposition products of indigo can be formed, they are in a minority

Flywheel energy storage systems in hybrid and distributed electricity generation

International audienceIn this article, we will demonstrate the benefit of the electromechanical storage of energy over long operating cycles (with time constants ranging from several minutes to a few hours), within the scope of decentralized electrical energy production. Both the principle and technology of the primary components used in an electromechanical accumulator will be presented herein. A number of well-known examples of systems will be shown in order to derive a summary state-of-the-art. We will then proceed by providing the example of a prototype developed at the SATIE Laboratory in the aim of designing a stationary accumulator for a domestic application requiring power on the order of one kilowatt