Comportement à la rupture à chaud et en fluage, évolution microstructurale de fibres issues de précurseurs organosiliciés.

The thermal stability of fibres from organosilicon precursors (pcs and pcsz) has been studied in terms of microstructural changes occurring during heat treatments and in terms of the evolution of mechanical properties in traction and creep. The high temperature behaviour of the fibres is influenced by the presence of oxygen-rich and free-carbon amorphous phases in the fibres as well as by the chemical nature of the atmosphere (e. g. Argon, co) during mechanical tests. The creep of si-c-o (nicalon) fibers with high oxygen levels is controlled by the viscoelastic nature and the thermal instabilitity of the silicon oxycarbon phase present at the joints of the sic grains. On the other hand, in the case of the fiber si-c (hi-nicalon) has a high rate of free carbon and does not contain oxygen, the proposed mechanism for creep is based on the depling and extension of the carbon layers in the direction of mechanical stress.La stabilite thermique de fibres issues de precurseurs organosilicies (pcs et pcsz) a ete etudiee sur le plan des modifications microstructurales survenant au cours de traitements thermiques et sur celui de l'evolution des proprietes mecaniques en traction et en fluage. Le comportement a haute temperature des fibres est influence par la presence de phases amorphes riches en oxygene et de carbone libre dans les fibres ainsi que par la nature chimique de l'atmosphere (e. g. Argon, co) lors des essais mecaniques. Le fluage des fibres si-c-o (nicalon) a fort taux d'oxygene est controle par la nature viscoelastique et l'instabilite thermique de la phase oxycarbure de silicium presente aux joints des grains de sic. En revanche, dans le cas de la fibre si-c (hi-nicalon) a fort taux de carbone libre et ne contenant pas d'oxygene, le mecanisme propose pour le fluage repose sur le deplissement et l'extension des couches de carbone dans la direction de la sollicitation mecanique

Comportement à la rupture à chaud et en fluage, évolution microstructurale de fibres issues de précurseurs organosiliciés.

The thermal stability of fibres from organosilicon precursors (pcs and pcsz) has been studied in terms of microstructural changes occurring during heat treatments and in terms of the evolution of mechanical properties in traction and creep. The high temperature behaviour of the fibres is influenced by the presence of oxygen-rich and free-carbon amorphous phases in the fibres as well as by the chemical nature of the atmosphere (e. g. Argon, co) during mechanical tests. The creep of si-c-o (nicalon) fibers with high oxygen levels is controlled by the viscoelastic nature and the thermal instabilitity of the silicon oxycarbon phase present at the joints of the sic grains. On the other hand, in the case of the fiber si-c (hi-nicalon) has a high rate of free carbon and does not contain oxygen, the proposed mechanism for creep is based on the depling and extension of the carbon layers in the direction of mechanical stress.La stabilite thermique de fibres issues de precurseurs organosilicies (pcs et pcsz) a ete etudiee sur le plan des modifications microstructurales survenant au cours de traitements thermiques et sur celui de l'evolution des proprietes mecaniques en traction et en fluage. Le comportement a haute temperature des fibres est influence par la presence de phases amorphes riches en oxygene et de carbone libre dans les fibres ainsi que par la nature chimique de l'atmosphere (e. g. Argon, co) lors des essais mecaniques. Le fluage des fibres si-c-o (nicalon) a fort taux d'oxygene est controle par la nature viscoelastique et l'instabilite thermique de la phase oxycarbure de silicium presente aux joints des grains de sic. En revanche, dans le cas de la fibre si-c (hi-nicalon) a fort taux de carbone libre et ne contenant pas d'oxygene, le mecanisme propose pour le fluage repose sur le deplissement et l'extension des couches de carbone dans la direction de la sollicitation mecanique

Casual spectators and die-hard fans’ reactions to their team defeat: A look at the role of territorial identification in elite French rugby

International audienc

Refining the relationship between ingroup identification and identity management strategies in the sport context: The moderating role of gender and the mediating role of negative mood

The aim of this exploratory research was to refine the relationship between ingroup identification and three classical identity-management strategies: individual mobility, social competition and social creativity. More specifically, in the particular context of sport spectators' reactions to their team loss, we tested the moderating role of gender in differentiating the use of CORFing (distancing) strategy and the mediating role of negative mood in differentiating the use of social competition and social creativity strategies. To this end, 173 French physical education students were asked to watch an edited video clip about a defeat of the French national rugby union team. As expected, and consistent with past research, results first showed that the amount of team identification is a reliable determinant of the participants' choice of an identity management strategy. Highly identified spectators were more associated with engaging themselves in ingroup-protective behaviors (i.e., blasting and boosting) than spectators low in team identification who, in contrast, privileged distancing strategies (i.e., CORFing). Moreover, results revealed that participant's gender moderates the link between ingroup identification and CORFing strategy, and that negative mood mediates the ingroup identification—blasting strategy relationship. Theoretical implications of these moderating and mediating effects are then discusse

High temperature behaviour of a wide petrographic range of siliceous and calcareous aggregates for concretes

International audienc

Inventory of armourstone

Natural armourstone is widely used for hydraulic works, both in the coastal domain and in border of rivers and torrents, especially to protect against flood and the effects of waves and currents. To meet the expectations associated with this resource, an inventory of armourstone quarries was realized on a national scale in France. This inventory informs not only about the localization of quarries but also about the quality and the availability of materials. To fully optimize this inventory in a dynamic format, the association of all actors of the sector was preferred to archival research. This partnership approach led to project deliverables that can constitute durably a shared reference. The database can indeed be updated regularly thanks to the contacts established with the professionals of quarries. The access to this database is offered to a wide public: maritime and fluvial ports, local authorities in charge of planning and managing structures that protect against flood and other hydraulic hazards. This new database was organized considering its importance on the operational plan. This led to a hierarchical organization at two levels for each quarry face: first level, a synthesis sheet brings the essential information to realize choices upstream to the operational phases. Second level, a detailed specification sheet presents the technical characteristics observed in the past on the considered face. The atlas has two information broadcasting formats: a pdf file with browsing functions and a geographical information system that allows remote request of the database. These two media have their own updating rhythms, annual for the first and continue for the second

Inventory of armourstone

Natural armourstone is widely used for hydraulic works, both in the coastal domain and in border of rivers and torrents, especially to protect against flood and the effects of waves and currents. To meet the expectations associated with this resource, an inventory of armourstone quarries was realized on a national scale in France. This inventory informs not only about the localization of quarries but also about the quality and the availability of materials. To fully optimize this inventory in a dynamic format, the association of all actors of the sector was preferred to archival research. This partnership approach led to project deliverables that can constitute durably a shared reference. The database can indeed be updated regularly thanks to the contacts established with the professionals of quarries. The access to this database is offered to a wide public: maritime and fluvial ports, local authorities in charge of planning and managing structures that protect against flood and other hydraulic hazards. This new database was organized considering its importance on the operational plan. This led to a hierarchical organization at two levels for each quarry face: first level, a synthesis sheet brings the essential information to realize choices upstream to the operational phases. Second level, a detailed specification sheet presents the technical characteristics observed in the past on the considered face. The atlas has two information broadcasting formats: a pdf file with browsing functions and a geographical information system that allows remote request of the database. These two media have their own updating rhythms, annual for the first and continue for the second

Methodological quality of multivariate prognostic models for intracranial haemorrhages in intensive care units: a systematic review

International audienceObjectives Patients with severe spontaneous intracranial haemorrhages, managed in intensive care units, face ethical issues regarding the difficulty of anticipating their recovery. Prognostic tools help clinicians in counselling patients and relatives and guide therapeutic decisions. We aimed to methodologically assess prognostic tools for functional outcomes in severe spontaneous intracranial haemorrhages. Data sources Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations, we conducted a systematic review querying Medline, Embase, Web of Science, and the Cochrane in January 2020. Study selection We included development or validation of multivariate prognostic models for severe intracerebral or subarachnoid haemorrhage. Data extraction We evaluated the articles following the CHecklist for critical Appraisal and data extraction for systematic Reviews of prediction Modelling Studies and Transparent Reporting of multivariable prediction model for Individual Prognosis Or Diagnosis statements to assess the tools’ methodological reporting. Results Of the 6149 references retrieved, we identified 85 articles eligible. We discarded 43 articles due to the absence of prognostic performance or predictor selection. Among the 42 articles included, 22 did not validate models, 6 developed and validated models and 14 only externally validated models. When adding 11 articles comparing developed models to existing ones, 25 articles externally validated models. We identified methodological pitfalls, notably the lack of adequate validations or insufficient performance levels. We finally retained three scores predicting mortality and unfavourable outcomes: the IntraCerebral Haemorrhages (ICH) score and the max-ICH score for intracerebral haemorrhages, the SubArachnoid Haemorrhage International Trialists score for subarachnoid haemorrhages. Conclusions Although prognostic studies on intracranial haemorrhages abound in the literature, they lack methodological robustness or show incomplete reporting. Rather than developing new scores, future authors should focus on externally validating and updating existing scores with large and recent cohorts