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1.
Ricardo Beristain‐Cardoso Anne‐Claire Texier Reyes Sierra‐Álvarez Jim A Field Elías Razo‐Flores Jorge Gómez 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(9):1197-1203
BACKGROUND: Simultaneous removal of sulfur, nitrogen and carbon compounds from wastewaters is a commercially important biological process. The objective was to evaluate the influence of the CH3COO?/NO3? molar ratio on the sulfide oxidation process using an inverse fluidized bed reactor (IFBR). RESULTS: Three molar ratios of CH3COO?/NO3? (0.85, 0.72 and 0.62) with a constant S2?/NO3? molar ratio of 0.13 were evaluated. At a CH3COO?/NO3? molar ratio of 0.85, the nitrate, acetate and sulfide removal efficiencies were approximately 100%. The N2 yield (g N2 g?1 NO3?‐N consumed) was 0.81. Acetate was mineralized, resulting in a yield of 0.65 g inorganic‐C g?1 CH3COO?‐C consumed. Sulfide was partially oxidized to S0, and 71% of the S2? consumed was recovered as elemental sulfur by a settler installed in the IFBR. At a CH3COO?/NO3? molar ratio of 0.72, the efficiencies of nitrate, acetate and sulfide consumption were of 100%, with N2 and inorganic‐C yields of 0.84 and 0.69, respectively. The sulfide was recovered as sulfate instead of S0, with a yield of 0.92 g SO42?‐S g?1 S2? consumed. CONCLUSIONS: The CH3COO?/NO3? molar ratio was shown to be an important parameter that can be used to control the fate of sulfide oxidation to either S0 or sulfate. In this study, the potential of denitrification for the simultaneous removal of organic matter, sulfide and nitrate from wastewaters was demonstrated, obtaining CO2, S0 and N2 as the major end products. Copyright © 2008 Society of Chemical Industry 相似文献
2.
Edna R Meza‐Escalante Anne‐Claire Texier Flor Cuervo‐López Jorge Gómez Francisco J Cervantes 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(3):372-377
BACKGROUND: Many industrial discharges, such as those generated from petrochemical refineries, contain large amounts of sulfurous, nitrogenous and organic contaminants. Denitrification has emerged as a suitable technology for the simultaneous removal of these pollutants in a single reactor unit; however, more evidence is demanded to clarify the limitations of denitrification on the simultaneous removal of sulfide and phenolic contaminants and to optimize the biological process. The aim of this study was to evaluate the capacity of a denitrifying sludge to simultaneously convert sulfide and p‐cresol via denitrification. RESULTS: Sulfide was the preferred electron donor over p‐cresol, imposing a 5 h lag phase (required for complete sulfide removal) on organotrophic denitrification. Addition of sulfide (20 mg S2? L?1) to p‐cresol‐amended denitrifying cultures also decreased the reduction rate of nitrate and nitrite, as well as the production rate of nitrogen gas. Nitrite reduction rate was the most affected step by sulfide, decreasing from 35 to 21 mg N (g VSS d)?1. A synergistic inhibitory effect of nitrate and sulfide was also observed on nitrite reduction. Despite the effects of sulfide on the respiratory rates monitored, complete removal of nitrate, sulfide and p‐cresol could be achieved after 48 h of incubation. CONCLUSION: Our results suggest that simultaneous removal of sulfide and p‐cresol could be achieved in denitrifying reactors, but a large hydraulic residence time may be required to sustain an efficient process due to inhibitory effects of sulfide. Copyright © 2008 Society of Chemical Industry 相似文献
3.
Johan Montagnat Ákos Frohner Daniel Jouvenot Christophe Pera Peter Kunszt Birger Koblitz Nuno Santos Charles Loomis Romain Texier Diane Lingrand Patrick Guio Ricardo Brito Da Rocha Antonio Sobreira de Almeida Zoltán Farkas 《Journal of Grid Computing》2008,6(1):45-59
The medical community is producing and manipulating a tremendous volume of digital data for which computerized archiving,
processing and analysis is needed. Grid infrastructures are promising for dealing with challenges arising in computerized
medicine but the manipulation of medical data on such infrastructures faces both the problem of interconnecting medical information
systems to Grid middlewares and of preserving patients’ privacy in a wide and distributed multi-user system. These constraints
are often limiting the use of Grids for manipulating sensitive medical data. This paper describes our design of a medical
data management system taking advantage of the advanced gLite data management services, developed in the context of the EGEE
project, to fulfill the stringent needs of the medical community. It ensures medical data protection through strict data access
control, anonymization and encryption. The multi-level access control provides the flexibility needed for implementing complex
medical use-cases. Data anonymization prevents the exposure of most sensitive data to unauthorized users, and data encryption
guarantees data protection even when it is stored at remote sites. Moreover, the developed prototype provides a Grid storage
resource manager (SRM) interface to standard medical DICOM servers thereby enabling transparent access to medical data without
interfering with medical practice. 相似文献
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5.
This study was carried out mainly by quenching followed by isothermal annealing or continuous heating. X-ray diffraction, micrography, microhardness and dilatometry during quench were employed. By stepped quenching, it was found that the high-temperature β phase decomposes in different ways —either partial decomposition into Zr, leading finally to the (Zr+βNb) mixture indicated by the phase-diagram, or a diffusion-transformation into ω', or else a diffusionless transformation into ω. A fast quench breaks down the phase into a complex (β + ω + β″) structure. During isothermal anneals the β″ phase was found to vanish, while either ω' or Zr was formed according to temperature; meanwhile residual β became enriched in niobium. During continuous heating at rates less than 150°/h, the quench-product, ω, reverts to β; then, above 600°C, is transiently deposited but disappears again above 700°C to yield the equilibrium high-temperature phase, β containing 17 wt % niobium. 相似文献
6.
Human hands sweat in different circumstances and the presence of sweat can alter the friction between the hand and contacting
surface. It is, therefore, important to understand how hand moisture varies between people, during different activities and
the effect of this on friction. In this study, a survey of fingertip moisture was done. Friction tests were then carried out
to investigate the effect of moisture. Moisture was added to the surface of the finger, the finger was soaked in water, and
water was added to the counter-surface; the friction of the contact was then measured. It was found that the friction increased,
up until a certain level of moisture and then decreased. The increase in friction has previously been explained by viscous
shearing, water absorption and capillary adhesion. The results from the experiments enabled the mechanisms to be investigated
analytically. This study found that water absorption is the principle mechanism responsible for the increase in friction,
followed by capillary adhesion, although it was not conclusively proved that this contributes significantly. Both these mechanisms
increase friction by increasing the area of contact and therefore adhesion. Viscous shearing in the liquid bridges has negligible
effect. There are, however, many limitations in the modelling that need further exploration. 相似文献
7.
B. Ravat C. Platteau G. Texier B. Oudot F. Delaunay 《Journal of Nuclear Materials》2009,393(3):418-333
In order to investigate the martensitic transformation, an isothermal hold at −130 °C for 48 h was performed on a highly homogenized PuGa alloy. The modifications of the microstructure were characterized in situ thanks to a specific tool. This device was developed at the CEA-Valduc to analyze the crystalline structure of plutonium alloys as a function of temperature and more especially at low temperature using X-ray diffraction. The analysis of the recorded diffraction patterns highlighted that the martensitic transformation for this alloy is the result of a direct δ → α′ + δ phase transformation. Moreover, a significant Bragg’s peaks broadening corresponding to the δ-phase was observed. A microstructural analysis was made to characterize anisotropic microstrain resulting from the stress induced by the unit cell volume difference between the δ and α′ phases. The amount of α′-phase evolved was analyzed within the framework of the Avrami theory in order to characterize the nucleation process. The results suggested that the growth mechanism corresponded to a general mechanism where the nucleation sites were in the δ-grain edges and the α′-phase had a plate-like morphology. 相似文献
8.
Chitosan (CS) has received much attention as a functional biopolymer for designing various hydrogels for biomedical applications. This review provides an overview of the different types of CS‐based hydrogels, the approaches that can be used to fabricate hydrogel matrices with specific features and their applications in controlled drug delivery and tissue engineering. Emphasis is laid on the recent design concepts of hybrid hydrogels based on mixtures of CS and natural or synthetic polymers, interpenetrating polymer networks as well as composite hydrogels prepared by embedding nanoparticles into CS matrices. © 2017 Society of Chemical Industry 相似文献
9.
Lenoir L Joubert-Zakeyh J Texier O Lamaison JL Vasson MP Felgines C 《Journal of the science of food and agriculture》2012,92(7):1570-1572
BACKGROUND: Inflammatory bowel diseases consist of uncontrolled intestinal inflammation leading to mucosal disruption. Polyphenols are micronutrients with antioxidant and anti‐inflammatory properties and may play an interesting role in the prevention of intestinal inflammation. Lemon verbena (Aloysia triphylla (L'Herit.) Britton, Verbenaceae) infusion is a popular herbal drink rich in polyphenols. This study evaluated the protective effects of lemon verbena infusion consumption on the development of dextran sulfate sodium (DSS)‐induced colitis in rats. The infusion was given to rats as a drink providing 82 µmol polyphenols day?1 for 21 days. Colitis was induced with 40 g l?1 DSS in the drink for the last 7 days. RESULTS: Lemon verbena infusion treatment restored body weight gain and prevented colonic shortening. Despite no protective effect on myeloperoxidase activity, A. triphylla infusion limited histological colonic alterations. CONCLUSION: The results suggest that lemon verbena infusion partially protects rats against DSS‐induced inflammation. Copyright © 2011 Society of Chemical Industry 相似文献
10.
Texier Damien Monceau Daniel Selezneff Serge Longuet Arnaud Andrieu Eric 《Metallurgical and Materials Transactions A》2020,51(4):1475-1480
Metallurgical and Materials Transactions A - The micromechanical properties of a $$beta $$-(Ni,Pt)Al bond-coating was investigated between $$700,^circ hbox {C}$$ and $$1000,^circ hbox {C}$$... 相似文献