Etude d’un procédé hybride\ud Adsorption / Bioréacteur à membranes pour\ud le traitement des effluents industriels

La présence de composés toxiques à l’entrée des opérations d’épuration induit des problèmes en\ud terme de traitement par des procédés biologiques. Ces phénomènes sont accentués par une\ud variation temporelle de la composition en toxique (sorte de toxique et concentration) et donc de\ud la toxicité des effluents industriels. L’objectif de ce travail est de concevoir un procédé hybride\ud basé sur un couplage bioréaction/adsorption/séparation membranaire. Une étude des\ud phénomènes découplés, puis des différentes interactions a permis de caractériser les différentes\ud synergies au sein du bioréacteur à membrane hybride (BAM-H). Ainsi, l’étude de l’adsorption\ud d’un composé toxique dans un milieu biologique a montré la possibilité de bio-régénérer le\ud charbon actif et de limiter l’inhibition de la biomasse. L’ajout de charbon actif lors de la filtration\ud d’un milieu biologique permet de limiter le colmatage des membranes. L’étude du BAM-H a alors\ud montré qu’il était possible de traiter un effluent industriel par voie biologique sans période\ud d’acclimatation de la biomasse et sans engendrer de colmatage de la membrane, contrairement à\ud un bioréacteur à membranes conventionnel. Les mécanismes de dégradation du composé toxique\ud testé ont été précisés et comparés par rapport à un réacteur à boue activée. Ce travail a permis de\ud caractériser et de dégager les avantages du BAM-H par rapport aux différents procédés de\ud traitement des effluents industriels, notamment le bioréacteur à membrane

Absorption of toluene in silicone oil: effect of the solvent viscosity on hydrodynamics and mass transfer

International audienceThe purpose of this study was to compare toluene absorption performances using two PDMS of different viscosities (η = 5 and 50 mPas respectively) in terms of hydrodynamics and mass transfer. Three types of packing were tested in a counter-current packed gas-liquid contactor, Raschig rings, IMTP®, and Flexipac®. Hydrodynamic results showed that the viscosity of PDMS 50 is not a hurdle to be used with IMTP® or Flexipac®; the pressure drop being around 288 Pa m−1 for Flexipac® at the flooding point (FG = 0.99 Pa1/2; L’ = 4.95 kg m−2 s−1), which corresponds to an acceptable value for an industrial application. The determination of the loading zones showed that Raschig rings were not suitable for solvents having a high viscosity, such as PDMS 50; they resulted in high pressure drops if compared to IMTP® and Flexipac®. The mass transfer study showed that 100% removal efficiency can be reached for both PDMS using Flexipac®. For IMTP®, the removal efficiency is limited to 88% in the presence of PDMS 50. As a result, PDMS 50 should be a relevant absorbing liquid for the removal of toluene in the absorption–biodegradation process, and Flexipac® packing should be preferred to IMTP

Interpreting dynamic space-time panel data models

22 pagesInternational audienceThere is a great deal of literature regarding the asymptotic properties of various approaches to estimating simultaneous space-time panel models, but little attention has been paid to how the model estimates should be interpreted. The motivation for use of space-time panel models is that they can provide us with information not available from cross-sectional spatial regressions. LeSage and Pace (2009) show that cross-sectional simultaneous spatial autoregressive models can be viewed as a limiting outcome of a dynamic space-time autoregressive process. A valuable aspect of dynamic space-time panel data models is that the own- and cross-partial derivatives that relate changes in the explanatory variables to those that arise in the dependent variable are explicit. This allows us to employ parameter estimates from these models to quantify dynamic responses over time and space as well as space-time diffusion impacts. We illustrate our approach using the demand for cigarettes over a 30 year period from 1963-1992, where the motivation for spatial dependence is a bootlegging effect where buyers of cigarettes near state borders purchase in neighboring states if there is a price advantage to doing so.La littérature économétrique récente fait une place croissante à l'étude des propriétés asymptotiques des différentes méthodes d'estimation des modèles de données de panel spatio-temporels. Toutefois, force est de constater que peu d'attention est consacrée à l'interprétation économique de tels modèles malgré leur grand intérêt pour la modélisation des phénomènes économiques dans une dimension spatio-temporelle et le rôle qu'ils pourraient jouer dans l'évaluation des politiques économiques dans cette même dimension. Nous montrons dans ce papier que les coefficients estimés de ces modèles permettent d'expliciter non seulement la dynamique temporelle des impacts mais également leur dynamique spatiale et surtout de quantifier la diffusion spatio-temporelle de l'impact d'une variation d'une variable explicative. La méthode proposée est illustrée par une étude de la demande de cigarettes dans 46 Etats américains sur la période 1963-1992 en utilisant une base de données bien connue dans la littérature économétrique. La présence d'autocorrélation spatiale est ici motivée par un effet de " contrebande ". Les consommateurs proches des frontières d'un état achèteront en effet leurs cigarettes dans les états voisins si le prix des cigarettes y est inférieur à celui pratiqué dans leur propre Etat

Integration of an eco-design process within an SME: knowledge feedback on a recent development of a new range of hospital carts

Nowadays, in order to face increasing competition, businesses must differentiate through innovation, but also crucially by positioning themselves with respect to environmental concerns, in order to improve brand image. SMEs are particularly plagued with a lack in human, financial and time resources to integrate such aspects to design. In this paper, we propose a gradual approach (short-, medium- and long-term) to implement an eco-design process in SMEs. This process comprises four stages: analysis, sensitisation, eco-design strategy and sustained improvement. A first experimentation, in collaboration with a SME (MulTiroir-Controlec), allowed us to integrate this eco-design process in the development of a new product range of hospital carts. We present the results of the product development as well as an experience feedback on the project; today the company integrates this eco-design approach in its strategy

Role of TASK2 Potassium Channels Regarding Volume Regulation in Primary Cultures of Mouse Proximal Tubules

Several papers reported the role of TASK2 channels in cell volume regulation and regulatory volume decrease (RVD). To check the possibility that the TASK2 channel modulates the RVD process in kidney, we performed primary cultures of proximal convoluted tubules (PCT) and distal convoluted tubules (DCT) from wild-type and TASK2 knockout (KO) mice. In KO mice, the TASK2 coding sequence was in part replaced by the lac-Z gene. This allows for the precise localization of TASK2 in kidney sections using β-galactosidase staining. TASK2 was only localized in PCT cells. K+ currents were analyzed by the whole-cell clamp technique with 125 mM K-gluconate in the pipette and 140 mM Na-gluconate in the bath. In PCT cells from wild-type mice, hypotonicity induced swelling-activated K+ currents insensitive to 1 mM tetraethylammonium, 10 nM charybdotoxin, and 10 μM 293B, but blocked by 500 μM quinidine and 10 μM clofilium. These currents were increased in alkaline pH and decreased in acidic pH. In PCT cells from TASK2 KO, swelling-activated K+ currents were completely impaired. In conclusion, the TASK2 channel is expressed in kidney proximal cells and could be the swelling-activated K+ channel responsible for the cell volume regulation process during osmolyte absorptions in the proximal tubules

Genetic interaction network of the Saccharomyces cerevisiae type 1 phosphatase Glc7

<p>Abstract</p> <p>Background</p> <p>Protein kinases and phosphatases regulate protein phosphorylation, a critical means of modulating protein function, stability and localization. The identification of functional networks for protein phosphatases has been slow due to their redundant nature and the lack of large-scale analyses. We hypothesized that a genome-scale analysis of genetic interactions using the Synthetic Genetic Array could reveal protein phosphatase functional networks. We apply this approach to the conserved type 1 protein phosphatase Glc7, which regulates numerous cellular processes in budding yeast.</p> <p>Results</p> <p>We created a novel <it>glc7 </it>catalytic mutant (<it>glc7-E101Q</it>). Phenotypic analysis indicates that this novel allele exhibits slow growth and defects in glucose metabolism but normal cell cycle progression and chromosome segregation. This suggests that <it>glc7-E101Q </it>is a hypomorphic <it>glc7 </it>mutant. Synthetic Genetic Array analysis of <it>glc7-E101Q </it>revealed a broad network of 245 synthetic sick/lethal interactions reflecting that many processes are required when Glc7 function is compromised such as histone modification, chromosome segregation and cytokinesis, nutrient sensing and DNA damage. In addition, mitochondrial activity and inheritance and lipid metabolism were identified as new processes involved in buffering Glc7 function. An interaction network among 95 genes genetically interacting with <it>GLC7 </it>was constructed by integration of genetic and physical interaction data. The obtained network has a modular architecture, and the interconnection among the modules reflects the cooperation of the processes buffering Glc7 function.</p> <p>Conclusion</p> <p>We found 245 genes required for the normal growth of the <it>glc7-E101Q </it>mutant. Functional grouping of these genes and analysis of their physical and genetic interaction patterns bring new information on Glc7-regulated processes.</p

Numerical simulations of wave breaking

This paper is devoted to the numerical simulation of wave breaking. It presents the results of a numerical workshop that was held during the conference LOMA04. The objective is to compare several mathematical models (compressible or incompressible) and associated numerical methods to compute the flow field during a wave breaking over a reef. The methods will also be compared with experiments

Effect of Oils Categories on the Distribution of Polycyclic Aromatic Hydrocarbons and Derivatives in the Environment

Context and objective: The Migr’Hycar research project was initiated to provide decisional tools for risks connected to oil spill drifts in continental waters. This paper focuses on the distribution of polycyclic aromatic hydrocarbons (PAHs) from oils in water, air and oil slicks. Material and methods: Six petroleum oils covering a representative range of commercially available products were tested. Dynamic tests at laboratory scale were performed to study 41 PAHs and derivates, among them 16 EPA priority pollutants. Water soluble fraction protocol, stir bar sorptive extraction (SBSE) and high performance gas chromatography mass spectrometry (HPGC-MS) was used. Limit of quantification were lower than 1 ng.L-1 for each compounds. Results: A large variation in composition of the water soluble fraction depending on oil type and mixing time has been highlighted. Results have shown that evaporation is the primary mechanism of PAHs loss from spilled oil. The subsequent fate of hydrocarbons deposited in surface water is further influenced by volatilisation behaviour because of possible slick loss to the atmosphere. The water soluble fraction remains very low and is dominated by low molecular weight PAHS (e.g. naphthalenes)

Dynamic Behavior of Polycyclic Aromatic Hydrocarbons and Their Derivatives after Oils Spill in Water

Within the framework of Migr’Hycar research project, the fate of oil spill was studied with the aim to characterize their physical-chemical behaviour. For this purpose, seven petroleum oils com- mercially available were tested and the distributions of the water soluble components were deter- mined according to two experimental devices; laboratory conditions and pilot conditions in Pollu- drome. In the dissolved fraction, 41 polycyclic aromatic hydrocarbons and their derivates were quantified, among them are 16 EPA priority pollutants. A coupling of the stir bar sorptive extrac-tion method and high performance gas chromatography mass spectrometry were used. Analyses showed that naphthalenes series constitute the major part of the water soluble fraction from fresh oils. In fact, light and heavy molecules have different contributions to solubilization kinetics. From the results, a linear correlation was established between the density of oils and the times of max-imum solubilization. Moreover, the effect of 10% ethanol in gasoline was observed on the profile of solubilized PAHs in water. Kinetic patterns obtained with Polludrome showed the influence of surface water/oil ratio (WOR) on the volatilization process. Compared to laboratory conditions, the dynamic conditions of Polludrome led to an enhanced evaporation process, thus shifting the solubility peak