25 research outputs found

    Biofriendly ionic liquids for starch plasticization: a screening approach

    No full text
    International audienc

    Thermo-mechanical recycling of rubber: Relationship between material properties and specific mechanical energy

    No full text
    The studied and optimized devulcanization process is known as “High Shear Mixing” (HSM) recycling process. In the process the rubber is sheared between two metallic cones with special geometries. One cone is static as the other one rotates simultaneously and applies pressure to the material. Among the different parameters that are controlled and/or measured during the process two are highlighted for their importance: the temperature of the rubber, and the specific mechanical energy consumed during the process. It is shown that the energy consumed by the rotor can be correlated to the degree of devulcanization of the rubber which is measured by means of physicochemical analyses. An optimal state of surface activation on the treated rubber is also described. A physical model of the rubber network evolution along the HSM treatment is proposed

    Processing of wet biomass byproducts by hydrothermal liquefaction

    No full text
    International audienc

    Temporal changes in the biochemical composition of particulate organic matter sedimentation in the Bay of Banyuls-sur-Mer

    No full text
    Gross sedimentation rates (GSRs) were monitored together with meteorological data and the main biochemical characteristics of the collected material (i.e. organic content, C, N, total proteins, carbohydrates, lipids and available proteins) over a three year cycle at a shallow station (18 m) of the Bay of Banyuls, France. GSRs were between 0.26 (11/04/92) and 317.75 gDW m(-2) d(-1) (18/02/94). They followed an annual cycle with low and relatively constant values during spring and summer and high, variable Values during fall and winter. During the study GSRs correlated poorly (state of the sea, precipitation) or even non-significantly (wind speed) with the main meteorological parameters. GSRs correlated negatively with the organic content of the material collected within the sediment traps suggesting the importance of resuspension in controlling GSRs. This hypothesis is consistent with the fact that, among all the measured biochemical parameters, available proteins (i.e. enzymatically hydrolizable proteins) are the most negatively correlated with GSRs. Available proteins showed important temporal changes that are only partly described by changes in carbon and nitrogen contents. These results are discussed in relation to the conceptualisation and the modelling of benthic trophic networks. The major objectives of our research group within the framework of the second phase of the French "Programme National d'Oceanographie Cotiere" are briefly discussed.Les taux de sĂ©dimentation brute (GSR) ont Ă©tĂ© mesurĂ©s avec les principaux paramĂštres mĂ©tĂ©orologiques et les principales caractĂ©ristiques biochimiques (i.e. matiĂšre organique, C, N, protĂ©ines totales, hydrates de carbone, lipides et protĂ©ines disponibles) sur une pĂ©riode de trois ans Ă  une station (18 m de profondeur) situĂ©e en baie de Banyuls, France. Les GSR sont compris entre 0,26 (11/04/92) and 317,75 g m−2 j−1 (18/02/94). Ils suivent un cycle annuel avec des valeurs faibles et relativement constantes durant la pĂ©riode printemps-Ă©tĂ© et des valeurs plus fortes et beaucoup plus variables durant la pĂ©riode automne-hiver. Les taux de sĂ©dimentation brute ne sont corrĂ©lĂ©s avec les paramĂštres mĂ©tĂ©orologiques mesurĂ©s que faiblement (Ă©tat de la mer, prĂ©cipitation) ou mĂȘme pas significativement (vitesse du vent). Les taux de sĂ©dimentation brute sont corrĂ©lĂ©s nĂ©gativement avec les contenus organiques du matĂ©riel recueilli dans les piĂšges Ă  particules, ce qui suggĂšre l'importance du processus de resuspension dans le contrĂŽle des taux de sĂ©dimentation brute. Cette hypothĂšse est en accord avec le fait que, parmi tous les paramĂštres biochimiques mesurĂ©s, les protĂ©ines disponibles (i.e. dĂ©gradables enzymatiquement) sont les plus nĂ©gativement corrĂ©lĂ©es avec les taux de sĂ©dimentation brute. Les protĂ©ines disponibles montrent des variations temporelles importantes qui ne sont qu'imparfaitement dĂ©crites par les contenus en carbone et azote. Ces rĂ©sultats sont discutĂ©s en relation avec la conceptualisation et la modĂ©lisation des rĂ©seaux trophiques benthiques. Les principaux objectifs de notre groupe lors de la seconde phase du Programme national d'ocĂ©anographie cĂŽtiĂšre sont briĂšvement Ă©voquĂ©s

    Relationship between sedimentary organic matter and benthic fauna within the Gulf of Lion: synthesis on the identification of new biochemical descriptors of sedimentary organic nutritional value

    No full text
    The abilities of several biochemical characteristics of sedimentary organic matter to describe quantitative changes in benthic fauna were assessed based on several surveys carried out within the Gulf of Lion during the last decade. Two sets of high frequency samplings were carried out both inshore and offshore, together with an assessment of seasonal variability along a depth gradient, and a synoptic assessment of mesoscale spatial variability. The considered biochemical parameters were: total organic matter, organic carbon, nitrogen, total proteins, available proteins, carbohydrates, lipids, total and available amino acids. The considered faunal parameters were the abundance and the biomass of both meio- and macrofauna. Our results contribute to unravel the relative importance of food digestibility and composition in controlling particulate organic matter nutritional value. Spectra of both total and available amino acids were almost constant irrespective of the seasons and/or the environments, which were studied during these surveys. This underlines the role of particulate organic matter digestibility relative to its ability to meet specific nutritional requirements in controlling benthic fauna. Multivariate analysis used to relate biochemical and faunal parameters suggest that available amino acids and lipids are the best descriptors of food nutritional value. In contrast with carbohydrates, these two parameters are both associated with the most labile fraction of particulate organic matter. This result suggests that the use of the sum of proteins, carbohydrates and lipids as a proxy for labile organic matter is precluded at least in areas similar to the Gulf of Lion.Les aptitudes de plusieurs des caractĂ©ristiques biochimiques de la matiĂšre organique particulaire sĂ©dimentĂ©e Ă  dĂ©crire les changements quantitatifs de la faune benthique ont Ă©tĂ© comparĂ©es Ă  partir des rĂ©sultats de plusieurs campagnes de prĂ©lĂšvements ayant eu lieu dans le golfe du Lion au cours de ces dix derniĂšres annĂ©es. Ces travaux ont consistĂ© en deux suivis haute frĂ©quence conduits Ă  une station littorale et Ă  une station du large, en une Ă©valuation de la variabilitĂ© saisonniĂšre le long d’un gradient cĂŽte large, et, enfin, en une Ă©tude synoptique de la variabilitĂ© spatiale Ă  mesoĂ©chelle. Les paramĂštres biochimiques considĂ©rĂ©s sont la matiĂšre organique totale, le carbone organique, l’azote, les protĂ©ines totales, les protĂ©ines disponibles, les sucres, les lipides, les acides aminĂ©s totaux et les acides aminĂ©s disponibles. Les paramĂštres faunistiques considĂ©rĂ©s sont l’abondance et la biomasse de la meio- et de la macrofaune. Les rĂ©sultats obtenus contribuent Ă  dĂ©limiter l’importance relative de la digestibilitĂ© et de l’aptitude Ă  satisfaire les besoins nutritionnels dans la dĂ©finition de la valeur nutritive de la matiĂšre organique particulaire sĂ©dimentĂ©e. Ainsi, la constance des spectres en acides aminĂ©s totaux et disponibles quels que soient les environnements et les saisons Ă©tudiĂ©s, suggĂšre-t-elle un plus grand rĂŽle de la digestibilitĂ© de la matiĂšre organique particulaire que de son aptitude Ă  satisfaire des besoins nutritionnels spĂ©cifiques dans le contrĂŽle de la faune benthique. Par opposition aux sucres, les lipides et les acides aminĂ©s disponibles sont associĂ©s Ă  la fraction la plus labile de la matiĂšre organique particulaire. Ceci rend inopĂ©rant l’usage de la somme des concentrations en protĂ©ines, sucres et lipides en tant qu’indice de la fraction labile de la matiĂšre organique, au moins dans les zones directement comparables au golfe du Lion
    corecore