Quelques retours d'expérience d'instabilités de terrain liées aux exploitations pentées

8 p.National audienceSuite au recensement de plus de 1000 exploitations en gisements pentés ou filoniens français, des désordres caractéristiques liés à ce type d'exploitation sont passés en revue : effondrements localisés liés à une rupture de la couronne, à un débourrage, à une rupture du toit, affaissements dissymétriques... L'objectif est de caractériser ces désordres qui sont influencés par les méthodes d'exploitation et les caractéristiques géologiques propres à ce type de dépôt. Ce travail devra servir à une méthodologie d'évaluation des aléas en vue de l'élaboration des Plans de Prévention des Risques Miniers (PPRM)

Screening of french mining exploitations : a methodology and a national hierarchisation to evaluate the geotechnical risk

International audienceThe French Ministry, in charge of mining and post-mining issues, plans to perform as effectively as possible its future investigations (Mining Risk Prevention Plans, MRPP, in particular). In this way, an ambitious program, called Screening, has been engaged in order to classify and to evaluate all French mining sites according to their mining risk level and then, to perform a quick risk evaluation for the most critical sites. This process included an important stage of hierarchisation. After many months of works, a multi-criteria analysis (based on ELECTRE's method) was finally adopted. It required an appropriated selection of experts, an effective criteria definition, use of adapted tools and a precise validation before application to given mining sites. The different steps of this work are presented in this paperLe Ministère en charge, en France, de la gestion des problèmes miniers tente de planifier le plus efficacement possible ses futures études (Plans de Prévention des Risques Miniers, PPRM, notamment). Pour ce faire, un programme ambitieux, baptisé Scanning, a été engagé afin de classer et d'évaluer les risques, liés aux exploitations minières, de potentiels mouvements de terrains. Ce processus comprend une phase importante de hiérarchisation. Après de mois de réflexions, c'est une analyse de type multicritères (de la famille des méthodes ELECTRE) qui a finalement été retenue. Cette hiérarchisation nécessite de faire appel à un groupe d'experts, de définir des critères de hiérarchisation efficaces, d'utiliser des outils adaptés et de valider précisément chacune des étapes avant d'envisager de hiérarchiser des sites miniers. L'article suivant présente la démarche complète de cette mise en oeuvr

Transition from Cassie to Wenzel state in patterned soft elastomer sliding contacts

In this paper, we presented an experimental and theoretical analysis of the formation of the contact between a smooth elastomer lens and an elastomer substrate micropatterned with hexagonal arrays of cylindrical pillars. We show using a JKR model coupled with a full description of the deformation of the substrate between the pillars that the transition between the top to the full contact is obtain when the normal load is increased above a well predicted threshold. We have also shown that above the onset of full contact, the evolution of the area of full contact was obeying a simple scaling.Comment: 4 pages, 6 figures. Submitte

Chemical modification of PDMS surface without impacting the viscoelasticity: Model systems for a better understanding of elastomer/elastomer adhesion and friction

The influence of both viscoelastic and interfacial parameters on the surface properties of elastomers is difficult to study. Here, we describe a simple route to achieve surface modification of PDMS without impacting the viscoelastic properties of the bulk. PEG modified PDMS surfaces were synthesized by two step surface modification based on hydrosilylation. The covalent grafting of PEG on the surface has been evidenced by AFM and ATR-FTIR, and its effect on the hydrophilicity characterized by static and dynamic contact angle. The static water contact angle of the PEG-modified PDMS decreases from 110° (for unmodified PDMS) to 65°. Dynamic contact angles also show a significant decrease in both advancing and receding contact angles, along with a significant increase in the contact angle hysteresis, which can be related to an increase in the surface energy as estimated by JKR measurements. The viscoelastic properties of modified PDMS are found to be quantitatively comparable to those of the unmodified PDMS. This simple method is an efficient way to prepare model materials which can be used to get a better understanding of the exact contribution of the surface chemistry on surface properties of elastomers

Circularly polarized-thermally activated delayed fluorescent materials based on chiral bicarbazole donors

G. P. thanks the SCBM, the “PTC du CEA” (POLEM) and the ANR (iChiralight, ANR-19-CE07-0040) for funding and David Buisson, Amélie Goudet and Sabrina Lebrequier. J. C. and L. Fa. acknowledge the Ministère de l’Education Nationale, de la Recherche et de la Technologie, the CNRS and the Spectroscopies-CDTP core facility is also acknowledged. The St. Andrews team thanks the China Scholarship Council, 201906250199 to W. S. and 202006250026 to J. W., E. Z.-C. is a Royal Society Leverhulme Trust Senior Research fellow (SRF\R1\201089). We thank the EPSRC (EP/R035164/1) for funding.We describe herein a molecular design to generate circularly polarized thermally activated delayed fluorescence emitters in which chiral bicarbazole donors are connected to acceptor units via a rigid 8-membered cycle and how the nature of the donor and acceptor units affect the photophysical and chiroptical properties.Publisher PDFPeer reviewe

Routine gastric residual volume measurement and energy target achievement in the PICU: A comparison study

Critically ill children frequently fail to achieve adequate energy intake and some care practices, such as the measurement of gastric residual volume (GRV) may contribute to this problem. We compared outcomes in two similar European Pediatric Intensive Care Units (PICUs): one which routinely measures GRV (PICU-GRV) to one unit that does not (PICU-noGRV). An observational pilot comparison study was undertaken. 87 children were included in the study, 42 (PICU-GRV) and 45 (PICU-noGRV). There were no significant differences in the percentage of energy targets achieved in the first four days of PICU admission although PICU-noGRV showed more consistent delivery of median (and IQR) energy targets, and less under and over feeding for PICU-GRV and PICU-noGRV Day 1 37 (14-72) vs 44 (0-100); Day 2 97 (53-126) vs 100 (100-100), Day 3 84 (45-112) vs 100 (100-100) , Day 4 101 (63-124) vs 100 (100-100). The incidence of vomiting was higher in PICU-GRV. No necrotising enterocolitis was confirmed in either unit and ventilator acquired pneumonia rates were not significantly different (7.01 vs 12 5.31 per 1000 ventilator days; p=0.70) between PICU-GRV and PICU-noGRV units. Conclusions: The practice of routine gastric residual measurement did not significantly impair energy targets in the first four days of PICU admission. However, not measuring GRV did not increase vomiting, ventilator acquired pneumonia or necrotising enterocolitis, which is the main reason clinicians cite for measuring GRV. What is known?•The practice of routinely measuring gastric residual volume is widespread in critical care units•This practice is increasingly being questioned in critically ill patients, both as a practice that increases •the likelihood of delivering inadequate enteral nutrition amounts and as a tool to assess feeding tolerance What is new? •Not routinely measuring gastric residual volume did not increase adverse events of ventilator acquired pneumonia, necrotising enterocolitis or vomiting •In the first four days of PICU stay, energy target achievement was not significantly different, but the rates of under and over feeding were higher in the routine GRV measurement uni

Les marchands d'estampes à Paris et la pratique des affaires

séminaire « Sociologie de la pratique des affaires », EHESS – Paris, 2 mar

Les conservateurs de musées et la société culturelle locale : relation aux profanes et compétence relationnelle

2e congrès de l'Association française de sociologie, Bordeaux, 5-8 septembr

ADMINISTRER LA CULTURE DANS LES COLLECTIVITÉS FRANÇAISES. LES SERVICES CULTURELS ET LEURS LÉGITIMATIONS PROFESSIONNELLES

Cet article examine le cas des services culturels des collectivités françaises et montre que, des années 1970 à nos jours, leur histoire ne se comprend que rapportée aux enjeux professionnels de leurs responsables, communément appelés « directeurs des affaires culturelles ». L’essor de ces services s’accompagne d’une transformation de leurs objectifs professionnels, lesquels, après avoir contribué à produire un traitement dépolitisé des questions culturelles, en appellent dans la période récente à plus de transversalité et invitent à ré-encastrer la culture dans le social. Il en résulte la coexistence d’une pluralité de références professionnelles attachées à l’activité, lesquelles, loin de délégitimer ces services et leurs responsables, permettent la réaffirmation d’une fragile juridiction, dans un contexte de réformes et face à des auditoires variés, lesquels découlent de la bureaucratisation croissante de l’administration culturelle dans un contexte de décentralisation

Les conservateurs de musées face aux élus locaux et à l'Etat

séminaire « Musée, culture et société », Muséum National d'Histoire Naturelle de Paris, 11 décembr