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The search for efficient gas carriers for biomedical applications presents a challenging task due to the kinetics of gas adsorption/desorption. This article presents a novel approach utilizing Gd-LTL zeolite crystals for oxygen delivery combined with an MRI study.

Pour la première fois, les Cahiers de la recherche sur les droits fondamentaux se penchent sur le droit de propriété, à la suite d’une récente et riche littérature scientifique. On sait la place, le rôle et la fonction que ce droit – souvent entendu socialement comme droit individuel et privé de propriété – occupe dans les sociétés occidentales. C’est le cas en particulier en droit français qui consacre, depuis la Révolution française, la propriété comme un « droit inviolable et sacré » (art....

Acoustic ultrasound interrogation and deformation measurements have been used simultaneously as supplementary battery monitoring methods during external overheating and external short-circuit safety tests of LG INR-18650 MJ1 (NMC 811- G-SiOx) Li-ion cells. The short-circuit experiments showed that the MJ1 technology is protected against this type of thermal abuse by the current interruption device (CID) integrated in the positive terminal of the cell. The results indicate that the strain gage signal is able to provide very rapid alert for this type of battery safety breach due to an abrupt change of the cell pressure. It precedes the time of the increase of the skin temperature by an order of magnitude. The thermal stability experiments carried out in adiabatic rate calorimeter on completely charged and overcharged batteries at open circuit conditions, showed that the MJ1 technology is susceptible to self-heating by slow internal exothermic reactions starting above 60 °C. The subsequent process of thermal runaway starts when the temperature exceeds 140 C. The results from the extended monitoring of the cells during the thermal stability tests showed that the acoustic ultrasound interrogation data combined with data mapping and clustering of the signal provides advantageous indication for early detection of slowly approaching battery safety breach events.

Adsorption on various adsorbents of hydrogen and helium at temperatures close to their boiling points shows, in some cases, unusually high monolayer capacities. The microscopic nature of these adsorbate phases at low temperatures has, however, remained challenging to characterize. Here, using high-resolution cryo-adsorption studies together with characterization by inelastic neutron scattering vibration spectroscopy, we show that, near its boiling point (~20 K), H2 adsorbed on a well-ordered mesoporous silica forms a two-dimensional monolayer with a density more than twice that of bulk-solid H2, rather than a bilayer. Theoretical studies, based on thorough first-principles calculations, rationalize the formation of such a super-dense phase. The strong compression of the hydrogen surface layer is due to the excess of surface–hydrogen attraction over intermolecular hydrogen repulsion. Use of this super-dense hydrogen monolayer on an adsorbent might be a feasible option for the storage of hydrogen near its boiling point, compared with adsorption at 77 K.

Le professeur Jacques Caillosse fait partie des figures universitaires du droit public et en particulier du droit administratif en France. Son œuvre est souvent rattachée au mouvement intellectuel « critique du droit » – quand bien même il n’en a pas été un des animateurs – en raison de sa manière de penser le droit administratif en lien avec les sciences sociales. Depuis plusieurs décennies, celui qui est désormais professeur émérite de l’université Paris 2 Panthéon-Assas a disséqué les évol...

Nanocasting or hard templating is a versatile method to produce ordered mesoporous mixed transition metal oxides (MTMOs) with promising potential for both oxygen evolution reaction (OER) and oxygen...

présentation orale (20 min) de quelques résultats de la thèse de Vincent Gau; International audience

International audience; The normal operation of a 18650 Lithium-ion cells has been monitored using rectangular rosette strain gauge and a pair of piezoelectric transducers. The sensors for mechanical measurements provide information about the cell deformation mechanism and electrodes structure during the cycling. The strain gauge signal revealed three type of mechanical processes. The predominant deformation pattern during galvanostatic discharge process is an isotropic cylindrical shrinkage relevant to the extraction of lithium ions from the graphite negative electrode. In the case of low-rate discharge in cyclic voltammetry mode, the deformation pattern changes to spherical growth when the state of charge falls below 40. In contrast, the thermal shrinkage and growth of the cell corresponds to simple decrease of the cell diameter with much smaller hysteresis effect. The ultrasound interrogation is able to detect repeatable progressive change of the acoustic waveform transferred across the cell in direction of the jellyroll diameter, which depends on the state of charge and does not undergo any significant changes at different cycling rates. The impact of the state of health under 2h rated charge/discharge cycling at 25°C reveals slow progressive drift of the strain and acoustic signals corresponding to the growth of the cell size.

International audience; HKUST-1 nanocrystals (50-80 nm) were homogeneously dispersed in a polyetherimide (PEI) polymer matrix. The use of a capping agent (sodium formate) 2 prevented the agglomeration of HKUST-1 nanocrystals in the casting solution. The highly dispersed HKUST-1 nanocrystals were found to strengthen the interactions with the PEI and minimize the interfacial holes by providing more accessible Cu unsaturated metal sites for the C=O bonds on the five-membered rings of the PEI matrix. The PEI membrane loaded with 30 wt. % HKUST-1 nanocrystals (30-N-HKUST-1/PEI) showed a high H 2 permeability (193.3 Barrer at 25 °C under 1.5 bar) and good ideal H 2 /CH 4 and H 2 /CO 2 selectivity factor of 101.7 and 20.6 in a single gas test, respectively. In the gas mixture test, it also showed a good separation performance, i.e., a H 2 /CH 4 and H 2 /CO 2 selectivity factor of 82.4 and 16.5 was measured, respectively. The 30-N-HKUST/PEI membrane was tested in a gas mixture at different temperatures (25-100 °C), different pressures (0-3 bar) and various time (5-72 h) to study the performance in more realistic conditions thus to be further considered in the separation of syngas.

Depuis plusieurs décennies, les biens communs sont au centre d’une réflexion bouillonnante. Cet ouvrage collectif entend toutefois se démarquer de la production scientifique récente en se situant en dehors de la dimension éthique ou politique du bien commun, pour plutôt embrasser de manière pragmatique différentes occurrences d’une gestion commune des ressources (qu’elles soient naturelles ou non, matérielles ou immatérielles). Il s’agit, comme l’écrit Christian Bessy, d’aborder le bien commu...