Effect of modification by Pt and manufacturing processes on the microstructure of two NiCoCrAlYTa bond coatings intended for thermal barrier system applications

Few studies have already shown that Pt influences the diffusion of aluminium and therefore the microstructure of β-NiAl or γ-Ni/γ′-Ni3Al materials. Besides, several works have revealed that the addition of Pt to MCrAlY (M = Ni and/or Co) improves the oxidation/corrosion behavior of the material. Nevertheless, very few data have been published on the microstructure of such modified MCrAlYs. Then, the present work deals with the addition of Pt to two NiCoCrAlYTa coatings that differ by their manufacturing process. Characterization is carried out in order to understand the influence of Pt diffusion but also the effect of the manufacturing process on the final microstructure. The collected data from XRD, SEM, EDS and TEM analyses reveal that an Al uphill diffusion occurs during heat treatment due to the presence of the Pt layer. The Al diffusion from the NiCoCrAlYTa bulk to the Pt-rich surface is so extensive that no more β-phase remains within the core of the coating. Pt may also dissolve TaC, precipitates largely present in the non-modified NiCoCrAlYTa coatings. In addition to Pt, the microstructure of the NiCoCrAlYTa prior to Pt deposition and heat treatment, dependent on the NiCoCrAlYTa manufacturing process, greatly influences the final microstructure

Reconnaissance électrochimique supramoléculaire d'anions d'intêret biologique à l'aide de récepteurs dendritiques et à base de nanoparticules d'or

Nous avons synthétisé trois types de dendrimères différents: * des dendrimères à coeur colloïdal d'or (liaisons de coordination), * des dendrimères "classiques" (liaisons covalentes), * des dendrimères supramoléculaires (liaisons hydrogène). Leur étude pour la reconnaissance d'oxoanions, principalement d'H2PO4- et de l'ATP2-, a montré quelques différences intéressantes: * Les nanoparticules d'or dendronisées peuvent être utilisées pour la préparation d'électrodes modifiées recyclables. * Les dendrimères possédant des fonctions ferrocényles perméthylées sont plus stables et permettent un titrage plus "propre" des anions. * Les dendrimères formés par liaisons hydrogène possèdent des propriétés particulières de reconnaissance au cours du titrage des anions étudiés. La facilité d'accès à des objets moléculaires avec un grand nombre de fonctions périphériques, offertes par les colloïdes d'or dendronisés et par les dendrimères supramoléculaires nous ouvre le champs à de nombreuses autres idées d'assemblages. Et la reconnaissance de l'ATP2- nous invite à tendre encore plus vers la biologie et vers des études en milieu aqueux

Characterizing the Feeding Habits of the Testate Amoebae Hyalosphenia papilio and Nebela tincta along a Narrow "Fen-Bog" Gradient Using Digestive Vacuole Content and (13)C and (15)N Isotopic Analyses.

International audiencePopulation dynamics and feeding habits of the testate amoebae Nebela tincta and Hyalosphenia papilio were studied along a short "fen" to "bog" gradient in a Sphagnum-dominated mire (Jura, France). Samples were collected in living "top segments" (0-3cm) and early declining "bottom segments" (3-6cm) of Sphagnum fallax peat. Observations of digestive vacuole content and stable isotope analyses ((13)C and (15)N) were used to establish the feeding behavior of both testate amoeba species. Owing to their vertical distribution, the feeding habit of H. papilio was described from top segments, and that of N. tincta from bottom segments. Among identified food sources, those most frequently ingested by N. tincta were spores and mycelia of fungi (55%), microalgae (25%) and cyanobacteria (8.5%). For H. papilio, the most frequently ingested prey were ciliates (55%) and microalgae (35%). Nonmetric Multidimensional Scaling analysis clearly demonstrated that the two species did not have the same feeding habit along the "fen-bog" gradient, and furthermore that a significant spatial split exists in the feeding behavior of H. papilio. Additionally, isotope analyses suggested that H. papilio and N. tincta did not have the same trophic position in the microbial food web, probably resulting from their different feeding strategies

On the Understanding of TGO Growth and Spallation in Nickel Aluminides

This paper describes various parameters influencing oxidation kinetics, oxide’s morphology and spallation phenomena encountered while studying nickel aluminides in high temperature oxidation. Questions are raised about the possibility of making precise lifetime or failure predictions of coatings and TBCs systems. Changes in growth mechanism due to the presence of elements other than Ni and Al in nickel-aluminide base coatings, the effect of atmosphere, particularly water vapor, and the effect of surface preparation and of crystallographic orientation are the main parameters discussed in this work

The role of Media in reporting child abuse

This study looks at the short-term impact that the media coverage of children in need of protection had on the number of cases reported to child protection agencies. The number of reports (N = 11,646) made to these agencies in Canada was tallied each week during a 24-month period. During the same period, a content analysis of print media was conducted regarding child maltreatment and/or child protection services (CPS) to identify and count the number of articles published (N = 1,211) and single out media frenzy events. Results show a statistically significant relationship between media coverage and the number of cases reported to child protection agencies

Corynebacterium mucifaciensin an immunocompetent patient with cavitary pneumonia

BACKGROUND: Corynebacterium mucifaciens has been mainly isolated from skin, blood and from other normally-sterile body fluids. It has rarely been described as a human pathogen since its description. CASE PRESENTATION: We herein report the first case of cavitary pneumonia due to C. mucifaciens in an immunocompetent man returning from Maghreb. CONCLUSION: C. mucifaciens should be considered as important human pathogen in patients with severe illness and compatible history of exposure even in individuals with no clearly identified immunosuppression

Etude et modélisation de l'endommagement du contact revêtu soumis à des sollicitations de fretting-fatigue

Ce travail présente une analyse de l'endommagement des contacts revêtus en fretting-fatigue. Un modèle d'endommagement a été développé et couplé à notre modèle de contact semi-analytique. Ce modèle, basé sur la mécanique des milieux continus, permet de décrire le comportement élastique-endommageable du revêtement. Il s'appuie sur un critère d'endommagement écrit en déformation, pour modéliser l'évolution des propriétés du matériau entre son état sain (initial) et son état endommagé (final). Cette modélisation a permis d'analyser l'influence de plusieurs paramètres sur l'évolution de l'endommagement au cours du chargement cyclique

Entrevue guidée avec Colette Dion Hubert

Collette Dion-Hubert est une pionnière dans le domaine de l’ergothérapie et de l’utilisation de l’ergonomie de l’activité de travail en réadaptation au Québec. Selon elle, alors que l’ergothérapie procède d’une approche individuelle des problématiques, l’ergonomie apporte une vision plus globale qui est essentielle à la transformation des situations de travail pathogènes. Elle a comme espoir que les pénuries de main-d’œuvre qui se dessinent dans certains métiers créeront de nouvelles possibilités d’insertion sécuritaire des « personnes différentes » au travail.Collette Dion-Hubert is a pioneer in the field of occupational therapy and the use of ergonomics of the work activity in rehabilitation in Québec. According to her, while occupational therapy stems from an individual approach to the problems, ergonomics provides a more comprehensive view that is vital in the transformation of pathogenic work situations. Her hope is that the labour shortages that are occurring in some professions will create new possibilities for the safe integration of « different people » into the work.Colette Dion-Hubert es una pionera en el campo de la ergoterapia y de la utilización de la ergonomía de la actividad en readaptación, en Quebec. Según ella, mientras la ergoterapia enfoca los problemas de una manera individual, la ergonomía aporta una visión más global, esencial cuando se trata de transformar situaciones de trabajo patógenas. Colette Dion-Hubert tiene la esperanza que la penuria de mano de obra que se prevee en varios oficios, creará nuevas posibilidades para la inserción de « personas diferentes » a trabajos que respeten su seguridad

Modélisation du contact normal et tangentiel entre deux matériaux anisotropes

Un modèle de contact basé sur des méthodes semi analytiques, s'appuyant sur des solutions analytiques élémentaires a été développé. Il repose sur des techniques numériques adaptées aux spécificités des sollicitations tribologiques, notamment l'aspect multi échelle. Il permet de quantifier les champs de déplacements et de contraintes d'un matériau élastique anisotrope, en contact avec un second matériau anisotrope. Il est intéressant d'observer l'influence des directions privilégiées d'un matériau ainsi que celle de leurs orientations

Effect of bicarbonate and lactate buffer on glucose and lactate metabolism during hemodiafiltration in patients with multiple organ failure

Objective: To compare the effects of sodium bicarbonate and lactate for continuous veno-venous hemodiafiltration (CVVHDF) in critically ill patients. Design and settings: Prospective crossed-over controlled trial in the surgical and medical ICUs of a university hospital. Patients: Eight patients with multiple organ dysfunction syndrome (MODS) requiring CVVHDF. Intervention: Each patient received the two buffers in a randomized sequence over two consecutive days. Measurements and results: The following variables were determined: acid-base parameters, lactate production and utilization (13C lactate infusion), glucose turnover (6,62H2-glucose), gas exchange (indirect calorimetry). No side effect was observed during lactate administration. Baseline arterial acid-base variables were equal with the two buffers. Arterial lactate (2.9 versus 1.5mmol/l), glycemia (+18%) and glucose turnover (+23%) were higher in the lactate period. Bicarbonate and glucose losses in CVVHDF were substantial, but not lactate elimination. Infusing 13C lactate increased plasma lactate levels equally with the two buffers. Lactate clearance (7.8±0.8 vs 7.5±0.8ml/kg per min in the bicarbonate and lactate periods) and endogenous production rates (14.0±2.6 vs 13.6±2.6mmol/kg per min) were similar. 13C lactate was used as a metabolic substrate, as shown by 13CO2 excretion. Glycemia and metabolic rate increased significantly and similarly during the two periods during lactate infusion. Conclusion: Lactate was rapidly cleared from the blood of critically ill patients without acute liver failure requiring CVVHDF, being transformed into glucose or oxidized. Lactate did not exert undesirable effects, except moderate hyperglycemia, and achieved comparable effects on acid-base balance to bicarbonat