Search results for "RATES"
showing 10 items of 1636 documents
Caractérisation de la dynamique de l'eau et des intrants à la parcelle: comparaison de dispositifs
2017
Notre système d’agriculture intensif cause une pollution accrue des eaux souterraines par lixiviationdes traitements appliqués sur les parcelles. Notamment l’utilisation des engrais azotés est, depuis 65 ans, enconstante augmentation. Cependant, cet azote rejoint les nappes phréatiques, rendant l’eau impropre à laconsommation. Le diagnostic de cette pollution azotée est donc un enjeu majeur de santé publique et est lié àdes conséquences économiques importantes car une nappe polluée devra être traitée et une autre nappeservira à la consommation, ce qui demande de nouvelles installations. Des instruments ont été créés pourprélever l’eau qui lixivie sous les parcelles agricoles afin d’analyser…
Task-specific ionic liquid for the depolymerisation of starch-based industrial waste into high reducing sugars
2014
Development of a simple route for the catalytic conversion of starch-based industrial waste (potato peels) and potato starch into reducing sugars was investigated in two ionic liquids for comparison – 1-allyl-3-methylimidazolium chloride [AMIM]Cl and 1-(4-sulfobutyl)-3-methylimidazolium chloride [SBMIM]Cl. Over a two hour period, a 20 wt% solution containing up to 43% and 98% of reducing sugars at low temperature in aqueous [SBMIM]Cl was achieved for the starch-based waste and the potato starch, respectively. In addition, the use of microwave and low frequency ultrasound to perform the depolymerisation of the raw starch-based material was explored and compared with conventional heating proc…
Modelling hydrolysis: Simultaneous versus sequential biodegradation of the hydrolysable fractions
2018
Hydrolysis is considered the limiting step during solid waste anaerobic digestion (including co-digestion of sludge and biosolids). Mechanisms of hydrolysis are mechanistically not well understood with detrimental impact on model predictive capability. The common approach to multiple substrates is to consider simultaneous degradation of the substrates. This may not have the capacity to separate the different kinetics. Sequential degradation of substrates is theoretically supported by microbial capacity and the composite nature of substrates (bioaccessibility concept). However, this has not been experimentally assessed. Sequential chemical fractionation has been successfully used to define i…
Etude des mécanismes physiologiques et moléculaires permettant la prise en charge des substrats hydrophobes par la levure Yarrowia lipolytica au nive…
2012
Yarrowia lipolytica can grow on many hydrophobic substrates and metabolize them via the β-oxidation pathway or store them into lipid bodies. The first contact between the cell and the hydrophobic substrates is by the cell wall. In this step, cell-wall proteins (CWP), β-glucane and chitin of the cell wall could play an important role for the adhesion and uptake of hydrophobic substrates. The aim of this work was to study the effect of a hydrophobic carbon source (compared with glucose) and the culture medium composition on the cell wall composition and the melanin production by Y. lipolytica. The results of our biochemical and molecular analysis showed that the presence of methyl oleate and …
Les expositions orales à un mélange de faibles doses de pesticides représentatif des usages bretons altèrent le métabolisme de rates gestantes exposé…
2014
National audience
Characterization of the biosynthesis of saponins during seed development in peas (Pisum sativum)
2019
National audience; The use of pulses as ingredients for the production of food products rich in plant proteins is increasing. However, protein fractions prepared from pea or other pulses contain significant amounts of saponins, glycosylated triterpenes which can impart a bitter taste to the final food product. Bitter flavours are currently either removed by energy-requiring physico-chemical treatments or masked by additives. We are in the process of identifying and characterizing the genes involved in saponin biosynthesis during pea seed development, with the objective of identifying mutants in which seed saponins no longer accumulate. To do this we have applied a saponin extraction protoco…
Spatial distribution of ammonia-oxidizing bacteria and archaea across a 44-hectare farm related to ecosystem functioning
2011
Characterization of spatial patterns of functional microbial communities could facilitate the understanding of the relationships between the ecology of microbial communities, the biogeochemical processes they perform and the corresponding ecosystem functions. Because of the important role the ammonia-oxidizing bacteria (AOB) and archaea (AOA) have in nitrogen cycling and nitrate leaching, we explored the spatial distribution of their activity, abundance and community composition across a 44-ha large farm divided into an organic and an integrated farming system. The spatial patterns were mapped by geostatistical modeling and correlations to soil properties and ecosystem functioning in terms …
Systèmes agro-sylvo-pastoraux, propriété et usages au Moyen Âge et à l’époque moderne : quelques aspects factuels et historiographiques pour la Bourg…
2017
International audience
Ondes scélérates optiques
2008
International audience; Nous montrons que les systèmes fibrés présentent des caractéristiques remarquables pour la génération et le contrôle d'impulsions rares et intenses similaires aux vagues scélérates océaniques. En particulier, l'amplificateur Raman faiblement dispersif pompé par une onde incohérente a permis de mettre en évidence l'apparition d'ondes scélérates optiques. Un bon accord théorie - expérience est observé.
Vaporization characteristics of 1-propanol droplets at high temperatures
2011
International audience; The gasification of a droplet via vaporization is one of the main processes in combustion systems, namely diesel and propulsion engines. In these combustion systems, always the liquid fuel is atomized as a cloud of droplets in the chamber, which then vaporizes, and mixes with the oxidant and burns to release heat. Therefore, to afford a better knowledge especially in modelling complex spray flows and mixture formation issues, the study of the droplet vaporization which involves mass, heat and momentum transfer processes is really vital. Alcohol has been chosen for this particular study due to its potential as an alternative fuel to the current conventional hydrocarbo…