Demonstration of the triboelectricity effect by the flow of liquid water in the insulating pipe

This paper demonstrates the tribolelectricity by the flow of water in an insulating pipe. A theoretical analysis showing the relation between the electric discharge and the system hydromechanical parameters is developed. Based on the macroscopic RC-circuit modeling of the system understudy, techniques allowing to minimize the discharge effect are introduced. With two different demonstrators, as predicted in theory, a voltage variation up to 300 mV is observed by using pipes having mm-diameter and pure water with 45 cm³ s^?1 flow rate. Finally, an application for the risk prevention caused by the explosion for the gas filling of engine fuel tank is discussed.     

Sur la stabilité thermique des étalons analytiques.iv

In this fourth article on standards the authors have plotted the thermolysis curves and ascribed the infrared absorption spectra of 12 substances in the solid state. These substances can be used in various instances for making standard solutions for chemical analysis.     

Interprétation des spectres d'absorption infrarouges de phosphites et d'hypophosphites métalliques

Résumé L'étude de 15 hypophosphites et de 6 phosphites métalliques en poudre, entre 300 et 3700 cm^–1 permet une interprétation des spectres infrarouges avec la considération des structures moléculaires et la comparaison avec les spectres Raman des solutions. Relativement à ce dernier point, les spectres infrarouges apparaissent beaucoup plus complexes.

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Summary The study of 15 hypophosphites and 6 metal phosphites in the form of powders, between 300 and 3700 cm^–1, allows an interpretation of the infra red spectra with consideration of the molecular structures and a comparison with the Raman spectra of the solutions. With respect to the latter point, the infra red spectra seem much more complex.

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Zusammenfassung Die Untersuchung von15 Metallhypophosphiten und 6 Metallphosphiten in Pulverform in dem Bereich zwischen 300 und 3700 cm^–1 ermöglicht eine Interpretation der Infrarotspektren in Bezug auf ihre Molekülstruktur und deren Vergleich mit den Ramanspektren ihrer Lösungen. Dieser zeigt, daß die Infrarotspektren sehr viel komplexerer Natur sind.

     

Sur la stabilité thermique des étalons analytiques vii

The thermolysis curves and infra-red spectra between 6 and 15 μ are given for 12 substances that are used as standards in analytical chemistry.     

Sur le dosage gravimétrique du sulfate de baryum en présence de fer

Résumé L'analyse par spectrographie infrarouge et par rayons X indique que le fer n'est pas combiné au sulfate de baryum précipité mais retenu fortement en quantités relativement faibles (1% au maximum), tout en colorant intensément le précipité. Il est très probable qu'il s'agisse d'une insertion sous forme d'oxyde à l'exclusion d'eau, d'oxhydriles et d'anions chlore.

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Summary Analysis by infrared spectrography and byx-rays indicates that iron is not combined with precipitated barium sulfate but is held firmly in relatively small amounts (1% maximum), though strongly coloring the precipitate. It is very likely that this involves entrance in the form of anhydrons oxide, hydrated oxide and chlorine anions.

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Zusammenfassung Infrarot- und röntgenspektrographische Analysen ergaben, daß Eisen mit Bariumsulfat bei dessen Fällung keine Verbindung bildet, daß aber relativ geringe Mengen (maximal 1%) sehr hartnäckig festgehalten werden. Dadurch wird der Niederschlag intensiv gefärbt. Wahrscheinlich handelt es sich um Einschlüsse des Eisens in Form des wasserfreien Oxyds und des Oxydhydrats und der Chlorionen.

     

La thermoluminescence de la glace; Les effects de la deformation plastique

We have studied the thermoluminescence of polycrystalline ices irradiated by ultraviolet light at liquid-nitrogen temperature. The effect of plastic deformation and annealing has been confirmed. The trap depth calculated from the law of light intensity variation with temperature, is sensibly equal to 0.09 eV.     

Shape of tetradecyltrimethylammonium chloride aggregates at liquid/solid interfaces in mixtures of water and formamide

Here we report the visualization by AFM of the adsorbed layer structures of the cationic surfactant tetradecyltrimethylammonium chloride (TTAC) on graphite and mica in solutions of formamide and formamide/water mixtures.