Self-Transforming Configuration Based on Atmospheric-Adaptive Materials for Solid Oxide Cells

Solid oxide cells (SOC) with a symmetrical configuration have been focused due to the practical benefits of such configurations, such as minimized compatibility issues, a simple fabrication process and reduced cost compared to SOCs with the asymmetrical configuration. However, the performance of SOCs using a single type of electrode material (symmetrical configuration) is lower than the performance of those using the dissimilar electrode materials (asymmetrical configuration). Therefore, to achieve a high-performance cell, we design a 'self-transforming cell' with the asymmetric configuration using only materials of the single type, one based on atmospheric adaptive materials. Atmospheric-adaptive perovskite Pr0.5Ba0.5Mn0.85Co0.15O3-delta (PBMCo) was used for the so-called self-transforming cell electrodes, which changed to layered perovskite and metal in the fuel atmosphere and retained its original structure in the air atmosphere. In fuel cell mods, the self-transforming cell shows excellent electrochemical performance of 1.10Wcm(-2) at 800 degrees C and good stability for 100 h without any catalyst. In electrolysis mode, the moderate current densities of -0.42A cm(-2) for 3 vol.% H2O and -0.62 A cm(-2) for 10 vol.% H2O, respectively, were observed at a cell voltage of 1.3V at 800 degrees C. In the reversible cycling test, the transforming cell maintains the constant voltages for 30 h at +/- 0.2A cm(-2) under 10 vol. % H2O

Les techniques de séparation des colloïdes par ultrafiltration et les interactions matière organique - pesticides : limites et développement

The quantities of atrazine, simazine, terbutylazine and prométryne adsorbed on colloids from Seine river water are positively correlated to their octanol-water coefficient (log Kow). However, chlorophenylureas such as the linuron, diuron and chlortoluron show relative enrichment factor (retentat/permeat) 2-10 times higher than triazines. Pyrolysis-GC-MS analyses of permeat and retentat indicates a clear enrichment of the retentat with sugars and permeat with proteinaceous material . This preliminary data suggest several types of pesticide-organic matters interaction (p and hydrogen bonds). Nevertheless, systematic investigations have to be done to evaluate the influence of ultrafiltration membranes and/or the residual organic matter on pesticide sorption processes. / Les quantités d'atrazine, de simazine, de terbutylazine et de prométryne adsorbées par les fractions colloïdales d'eau de Seine sont corrélées positivement au logarithme du coefficient de partage octanol-eau (log Kow) de ces herbicides. En revanche, les phenylurées possédant un cycle benzénique chloré telles que le diuron, le linuron et le néburon présentent des coefficients d'enrichissement relatifs dans le rétentat enrichi en colloïdes 2 à 10 fois plus élevés que les triazines. L'analyse conjointe de la matière organique sur ces échantillons par pyrolyse-chromatographie en phase gazeuse-spectrométrie de masse montre un net enrichissement du rétentat en sucres et du perméat en matière protéinique. Ces premiers résultats suggèrent que plusieurs types d'interactions physiques et chimiques (liaisons p, liaisons "hydrogène", etc) sont susceptibles d'intervenir entre la matrice organique et certaines fonctions et structures chimiques des pesticides. Par ailleurs, pour des solutions dopées à 100 ppb, 50 % des pesticides restent adsorbés sur la membrane de polysulfone (10 KD) ce qui rend la technique de filtration tangentielle impropre à l'analyse des traces

A comparison of the environmental impact of pesticide multiresidues and their occurrence in river waters surveyed by liquid chromatography coupled in tandem with UV diode array detection and mass spectrometry

9 pages, 4 figures, 3 tables.-- PMID: 15051367 [PubMed].-- Printed version published May 2004.Twenty-two pesticides and metabolites selected on the basis of a regional priority list, were surveyed in surface river waters by high performance liquid chromatography coupled in tandem with UV diode array detection and mass spectrometry, after an off-line pre-concentration step. Pesticide concentrations ranged between 0.07 and 4.8 μg/l according to the compound and sampling period. Analytical results were linked to the environmental risk of pesticides, evaluated by their system investigation of risk by integration of score (SIRIS) rank.S. Irace-Guigand gratefully acknowledges the University Pierre and Marie Curie (Paris FRANCE) and the PIREN-Seine project for financial support of her Ph.D., as well as the help and encouragements of Professor Ghislain de Marsily.Peer reviewe