A force model for superfinish turning of pure copper with rounded edge tools at low feed rate

International audienceThis paper presents a model for force prediction of superfinish turning operation on pure copper. The model is divided in two parts. The first part computes the forces acting on the rake face of the tool. The second part computes the forces on the clearance face that are much more important in superfinish machining than in conventional machining

From large-scale to micro machining: a review of force prediction models

International audienceIn this paper, a reviewof work performed in the area of force modelling in metal cutting processes is presented. Past and present trends are described and criticised to compare their relevance with current requirements. Several approaches are reviewed, such as empirical, mechanistic and analytical models. The models' ability to predict forces, from rough machining to finish machining, is analysed

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

A force model for superfinish turning of pure copper with rounded edge tools at low feed rate

This paper presents a model for force prediction of superfinish turning operation on pure copper. The model is divided in two parts. The first part computes the forces acting on the rake face of the tool. The second part computes the forces on the clearance face that are much more important in superfinish machining than in conventional machining.thèse CEA financement CEA/SNECM

Développement d'un modèle d'efforts de coupe intégrant le contact en dépouille : application au tournage de superfinition du cuivre Cu-c2

The aim of this work is the modelling of cutting forces in superfinish machining of copper Cu-OFHC through the Tool-Edge-Pair method. The cutting force prediction allows to adapt machining conditions and tool geometries to improve their performance. This method is based on edge segmentation and elemental forces functions of cutting parameters applied on each segment. The link between the edge geometry and the cutting parameters is made by the force model. The sum of these elemental forces leads to the main forces acting on the tool. This study aims to compute these forces from three models. The first two models are based on phenomenological relations dependant on cutting parameters as chip thickness, tool geometry and edge quality. The third model is analytical and based on the three zones scheme assumed in chip formation mechanics. The primary shear zone is characterised by a Norton-Hoff constitutive law. The second and third zones, respectively at the tool-chip interface and on the clearance face are characterised by a stress distribution. The performances of these models are compared using the Tool-Edge-Pair method. The experimental data are obtained from images taken during the machining process and from force measurements. Orthogonal cutting tests were conducted on disc and tube samples to isolate the effect of the workpiece diameter on the contact along the clearance face of the tool.L'objectif de ces travaux est la modélisation des efforts de coupe dans le cas de la superfinition à l'outil coupant du cuivre Cu-c2 par le biais de la démarche Couple-Arête-Matière. La prédiction des efforts permet d'adapter les conditions de coupe pour une opération d'usinage où de définir les spécifications des outils lors de leur conception. Le Couple-Arête-Matière repose sur la discrétisation d'arête et la mise en place sur chaque élément d'arête des efforts élémentaires fonctions de la géométrie et des conditions de coupe locales. Cette dépendance de la géométrie et de ces conditions de coupe est introduite par la mise en place d'un modèle d'efforts. Par sommation sur la longueur d'arête en prise, il est possible de déterminer les efforts globaux dans les repères liés à l'outil ou à la pièce. Cette étude vise le calcul de ces efforts au travers de trois modèles. Les deux premiers modèles développés sont de type phénoménologique et calculent les efforts à partir des paramètres opératoires courants tels que l'épaisseur coupée, la géométrie de l'outil et la qualité de l'arête. Le troisième modèle est analytique et basé sur les mécanismes de formation du copeau. Les efforts sont déterminés à partir des contributions des trois zones communément identifiées ; la zone de cisaillement primaire est caractérisée par une loi de comportement de type Norton-Hoff, les deuxième et troisième zones, respectivement en contact avec le copeau et la face en dépouille sont caractérisées par une distribution de contraintes. Les performances de ces trois modèles sont comparées via le Couple-Arête-Matière. Les données expérimentales sont obtenues à partir d'images réalisées en cours d'usinage par une caméra à haute résolution ainsi que par des mesures d'efforts en coupe orthogonale sur des disques et des tubes, permettant la mise en évidence de l'effet du diamètre de la pièce usinée sur la zone de contact en dépouille

A method for three dimensional tolerance analysis and synthesis applied to complex and precise assemblies, in micro-assembly technologies and applications

International audienc

A method for three dimensional tolerance analysis and synthesis applied to complex and precise assemblies, in micro-assembly technologies and applications

International audienc

Navigating from live to virtual social interactions: looking at but not manipulating smartphones provokes a spontaneous mimicry response in the observers

By gathering data on people during their ordinary daily activities, we tested if looking at, but not manipulating, smartphones led to a mimicry response in the observer. Manipulating and looking at the device (experimental condition), more than its mere manipulation (control condition), was critical to elicit a mimicry response in the observer. Sex, age and relationship quality between the experimenter and the observer had no effect on the smartphone mimicry response that tended to decrease during social meals. Due to the role of food as a tool in increasing social affiliation, it is possible that during communal eating, people engage in other forms of mimicry involving facial expressions and postures rather than the use of objects. Understanding the ethological mechanisms of the use of smartphones at everyday-social scale could unveil the processes at the basis of the widespread/increasing use of these devices at a large scale

Le retour de la restitution (4): <br />Géopolitiques du patrimoine, éthiques du transfert, économies du retour

Séance 4 : Vers quoi retourner ? Modération : Alexandra GALITZINE (Cessma-Inalco) et Marian NUR GONI (Musée du Quai Branly) [00:00:00 à 10:08:07] Présentation par Alexandra GALITZINE (Cessma-Inalco) et Marian NUR GONI (Musée du Quai Branly) [10:08:07 à 23:05:09] Germain LOUMPET (archéologue et anthropologue, indépendant), « Pour un musée du retour » [23:05:09 à 39:00:19] Claire BOSC-TIÉSSÉ (Cnrs-Imaf) : « Décrire les objets, formater l’histoire» [39:00:19 à 01:02:00:17] Valérie PERLES (Directrice du Musée départemental Albert-Kahn) & Amandine YÉHOUÉTOMÈ (U. Paris 1), « Comment faire des Archives de la planète un patrimoine partagé ? L'exemple du fonds Dahomey » [01:02:00:17 à 01:19:47:11] Didier HOUÉNOUDÉ (U. Abomey-Calavi) & Richard SOGAN (ANPT), « Enjeux politiques et économiques du retour des objets spoliés » [01:19:47:11 à fin] DiscussionPrésentation du colloque : Repatriation strikes back. Sujet récurrent depuis une trentaine d’année, la question de la restitution des objets volés ou spoliés est de retour, dans un contexte politique a priori plus favorable. Si les préconisations du rapport Sarr-Savoy (2018) suscitent de vives confrontations au sein des mondes muséaux et marchands, cette journée d’études vise à dépayser le débat en donnant la parole aux acteurs, aux publics et aux pays concernés par le retour et l’accueil de ces objets. La restitution est-elle le fait du prince, ou l’aboutissement de décennies de réclamations successives? De quelle géopolitique est-elle le nom ? Quels sont les acteurs de cette histoire ? Quelles places donner aux diasporas longtemps ignorées par les musées européens ? Comment penser les transferts et les appropriations ici et là-bas ? Quels statuts ces objets sacrés et royaux devenus « fétiches de musées » vont-ils prendre lors de leur retour ? Quels seront leurs publics ? Comment considérer et expliquer les oppositions locales au retour ? Mêlant acteurs et chercheurs, organisée autour de questions vives et actuelles, mais aussi immémoriales, cette journée ambitionne de lancer le débat plutôt que de le clore. Programme Contacts : [email protected] / [email protected]