CC9 Livestock-Associated Staphylococcus aureus Emerges in Bloodstream Infections in French Patients Unconnected With Animal Farming

We report 4 bloodstream infections associated with CC9 agr type II Staphylococcus aureus in individuals without animal exposure. We demonstrate, by microarray analysis, the presence of egc cluster, fnbA, cap operon, lukS, set2, set12, splE, splD, sak, epiD, and can, genomic features associated with a high virulence potential in human

Evolution of microstructure and crystallographic texture during dissimilar friction stir welding of duplex stainless steel to low carbon-manganese structural steel

Electron backscattered diffraction (EBSD) was used to analyze the evolution of microstructure and crystallographic texture during friction stir welding of dissimilar type 2205 duplex stainless steel (DSS) to type S275 low carbon-manganese structural steel. The results of microstructural analyses show that the temperature in the center of stirred zone reached temperatures between Ac 1 and Ac 3 during welding, resulting in a minor ferrite-to-austenite phase transformation in the S275 steel, and no changes in the fractions of ferrite and austenite in the DSS. Temperatures in the thermomechanically affected and shoulder-affected zones of both materials, in particular toward the root of the weld, did not exceed the Ac 1 of S275 steel. The shear generated by the friction between the material and the rotating probe occurred in austenitic/ferritic phase field of the S275 and DSS. In the former, the transformed austenite regions of the microstructure were transformed to acicular ferrite, on cooling, while the dual-phase austenitic/ferritic structure of the latter was retained. Studying the development of crystallographic textures with regard to shear flow lines generated by the probe tool showed the dominance of simple shear components across the whole weld in both materials. The ferrite texture in S275 steel was dominated by D 1, D 2, E, E¯ , and F, where the fraction of acicular ferrite formed on cooling showed a negligible deviation from the texture for the ideal shear texture components of bcc metals. The ferrite texture in DSS was dominated by D 1, D 2, I, I¯ , and F, and that of austenite was dominated by the A, A¯ , B, and B¯ of the ideal shear texture components for bcc and fcc metals, respectively. While D 1, D 2, and F components of the ideal shear texture are common between the ferrite in S275 steel and that of dual-phase DSS, the preferential partitioning of strain into the ferrite phase of DSS led to the development of I and I¯ components in DSS, as opposed to E and E¯ in the S275 steel. The formations of fine and ultrafine equiaxed grains were observed in different regions of both materials that are believed to be due to strain-induced continuous dynamic recrystallization (CDRX) in ferrite of both DSS and S275 steel, and discontinuous dynamic recrystallization (DDRX) in austenite phase of DSS

Recristallisation Continue au Cours de la Déformation à Chaud d'un Aluminium 1200

La recristallisation dynamique continue se manifeste par la transformation progressive des sous-grains en grains. Une étude microstructurale effectuée par diffraction des électrons rétrodiffusés a permis de la mettre en évidence lors de la déformation par compression uniaxiale (0,7 Tf, 10-2 s-1) d'un aluminium 1200 (99,3 %).Continuous dynamic recrystallization is characterized by the progressive transformation of the subgrains into grains. This process was investigated by electron back scattered diffraction during uniaxial compression (0,7 Tf, 10-2 s-1) of a 1200 aluminium (99,3 %)

A la quête des points sensibles du bilan environnemental du traitement des boues combinant digestion anaérobie et déshydratation mécanique : une approche par l'ACV

International audienceDuring the last decades, European institution establishes regulations which aim at protecting the environment from the adverse effects of the collection, treatment and discharge of waste water imposing wastewater treatment plants (WWTP) to release a good water quality in the environment. The constant diminution of the organic pollution of wastewater due to higher performance of water treatment through biological treatments leads to an increase in sludge production. The treatment processes used to concentrate and stabilize the sludge are of great importance as the sewage sludge treatment line can constitute 25 % to 72 % of total emissions of the WWTP [1]. Our study aims to present the sensitivity of Life Cycle Assessment environmental impacts results of a sewage sludge treatment line combining primary and secondary sludge thickening, anaerobic digestion, press filter dewatering, sludge storage and land spreading as final disposal (reference scenario) according to several types of parameters. Life Cycle Assessment of the reference scenario was conducting using GaBi software and environmental impacts results with the Recipe method. A sensitivity analysis was then conducted by changing reference value with a range of value for four types of parameters relevant of the treatment process performances. The studied parameters are: (a) Primary and secondary sludge composition (N, Volatile matter, P, K, Mg, Ca), (b) Anaerobic digestion performances (Volatile matter abatement, N mineralization rate, P solubilization rate, biogas composition, Hydraulic Retention Time) (c) Dewatering performances (dewatered sludge dry content based on literature value, dewatered sludge dry content based on pressure, cake thickness, filtration duration, N, P and K capture rate, polymer and FeCl3 dosage) (d) Primary and secondary thickening performances (thickened sludge dry content, N, P and K capture rate) By analyzing the sensitivity of each environmental impact (global warming, acidification, eutrophication, human toxicity…) according to each studied parameter, we identified several hotspots that research should be focused on to improve the efficiency of treatment performances and so the environmental impact of the whole sewage sludge treatment line

Effect of TiH2 in the preparation of MMC Ti based with TiC reinforcement

International audienceMany studies were carried out on the elaboration Metal Matrix Composites (MMCs) and a wide variety of process is reported in the bibliography. For titanium based MMC, the basis material for these elaboration techniques mainly consists of atomized titanium powder. In this work a titanium hydride powder is used to elaborate Ti/TiC MMC. Although an additional dehydrogenation operation is required a significant decrease of the sintering temperature is expected with this basis powder. In this context, the behavior of titanium hydride powder mixed with 0, 10 and 20 vol.% TiC reinforcement is studied during densification by free sintering. The effects of particle size, temperature and rate of sintering reinforcement are discussed. The comparison of the TiH2 process with Ti HDH (Hydride Dehydride) and atomized Ti mixture is made with 10 vol.% reinforcement. The results indicate that the sintering temperature is lowered and the final densities achieved are higher if the hydride is used. Interactions between dehydrogenation and sintering mechanisms clearly appear for the higher sintering temperature rate (10 degrees C/min) and need specific attention to prevent porosity nucleation through hydrogen entrapment

Nano titanium carbide particle reinforced aluminumcomposite materials prepared by ball milling followed by reactive sintering

International audienceThe development of the aviation industry requires the use of new metallic materials with superiorspecific mechanical properties compared to existing materials. In particular, the metal matrix composites (MMC) reinforced by nano-particles draw attention due to their excellent machinability.However, it is well-known that handling nanoparticles in industry is problematic due to respect of safety rules regarding nanomaterials. In order to overcome this problem, we have demonstrated the feasibility to fabricate nanocomposite materials without using any starting nanoparticles. We studied the ternary system aluminum/carbon/titanium for which we have shown the possibility to create the nanoparticles of titanium carbide by a flash sintering. So, we fabricated the titanium carbide (TiC) nano particles reinforced aluminum matrix (Alnano TiC) composite, and demonstrated that the size of TiC nanoparticles could be controlled by both heating rate and dwell temperature. We observed avery narrow size distribution of particles, ranging from 25 to 90 nm. Observation by transmission electron microscopy revealed that the TiC nanoparticles were individually distributed in Alnano TiC composite and that the Al/nano TiC interface was intimate. Tensile tests have been performed on specimens with various TiC contents. It was found that the ultimate tensile strength of the Al34 vol percent nano TiC composite was higher than 600 MPa with a failure elongation of 4.2 percent. The observed ridge of pure Al on the fracture surface implies that pure Al contributes to the conservation of a remarkable failure elongation of the Al;nano TiC composite. The elongation reaches 7.2 percent with the TiC volumefraction of 27 percent

Microstructure and mechanical properties of an Al–TiC metal matrix composite obtained by reactive synthesis

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