Identification of the heat input during dry or MQL machining

Machining with minimum quantity lubrication (MQL) has been the focus of many scientific investigations since the last 20 years. Nevertheless an acceptable method of predicting the thermal influences on the workpiece quality has still not been developed. This paper describes a simulation approach to estimate the distribution of the cutting energy during machining. During machining, the cutting power is measured to calculate the specific cutting power for each machining process – here drilling, tapping and milling of aluminum. In parallel, the warm-up of the part is measured by fast response thermocouples implanted closed of the machined zone. These thermocouples identify the cutting energy entering into the work piece

Simulating the Heat Distortiion of a Cast Iron Brake Disc during Dry Machining

International audienceThe application of MQL or dry machining in mass production becomes more and more accepted. Dry (MQL) machining is a very efficient solution to reduce the usage of cutting fluids and represents an effective measure for an environmental friendly production. However, these techniques do not benefit any more from the stabilization in temperature obtained with cutting fluids. More important and more heterogeneous increases of the temperature are observed. This leads to distortions of the work piece during machining which are necessary to be taken into account to maintain the geometrical quality of the manufactured surfaces. In this paper, we present a strategy to handle these thermal induced distortions in an industrial context. This strategy couples finite element thermo-elastic simulations and temperature measurements of the work piece. In a first section, we describe a method to identify machined characteristics sensible to part temperature at loading. This method takes into account standard deviation of the process. A solution to adapt tool trajectories with a temperature measurement is proposed. Second part deals with distortions of the part during manufacturing. A method is proposed to simulate distortions along machining. These FEM simulations allow to identify impact of a machining on next operations. An application of the proposed approach for the machining of a cast iron brake disc is presented. Simulations are compared to measurements made in a dry manufacturing line

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Le catalan, entre linguistique et politique: Entretien avec Henri Boyer

International audienceThe Catalan tongue is a Roman language coming from the popular Latin previously spoken in the land of Roussillon and Catalonia. It is the day to day language of about 7 million people today, and it is the center of a very ancient and huge literature which first texts dated from the XIth century. An official language of Catalonia since 1716, Catalan has been forbidden by General Franco in 1939 and remained privately or secretly spoken until the democratic transition in Spain, when it came back to official use. For the last few years, the Catalan language has become the center of the Catalan nationalism, which could lead Catalonia to independence. Language, law and politics are tightly connected in this matter, even if the link between them is not easy to understand precisely.Langue romane parlée par plus de 7 millions de personnes dans le monde, le catalan est un idiome historiquement issu de la continuation autochtone du latin vernaculaire en usage en Roussillon et en Catalogne. De par sa relative stabilité, ainsi que la toponymie et la phonétique le démontrent, il est le support d’une littérature très ancienne qui remonte au XIème siècle et prolifère aujourd’hui. Son aire locutoire contemporaine s’étend, au-delà de la Catalogne proprement dite, à une partie de l’Aragon, à la région de Valence et aux Baléares. Langue officielle jusqu’en 1716 sur ce territoire, et co-officielle entre 1931 et 1939, le catalan a été interdit en 1939 par une ordonnance du Général Franco. Sous le régime franquiste, le matériel d’impression des éditeurs catalanistes fut ainsi confisqué, le dictionnaire de référence saisi, la censure instaurée, et nombre de livres détruits. Mais avec le retour de la démocratie, la Catalogne a obtenu un statut de co-officialité pour le catalan, et a engagé un programme de revitalisation, fondé notamment sur l’enseignement primaire immersif dans la langue. Depuis une dizaine d’années, le statut de la langue fait l’objet d’un contentieux devant les tribunaux, et alimente une partie du discours politique, et notamment du discours nationaliste, lequel occupe aujourd’hui en Catalogne une place importante. La langue est ici liée aux revendications institutionnelles, même si ce lien n’est pas en soi consubstantiel à la simple expression linguistique

Le catalan, entre linguistique et politique: Entretien avec Henri Boyer

International audienceThe Catalan tongue is a Roman language coming from the popular Latin previously spoken in the land of Roussillon and Catalonia. It is the day to day language of about 7 million people today, and it is the center of a very ancient and huge literature which first texts dated from the XIth century. An official language of Catalonia since 1716, Catalan has been forbidden by General Franco in 1939 and remained privately or secretly spoken until the democratic transition in Spain, when it came back to official use. For the last few years, the Catalan language has become the center of the Catalan nationalism, which could lead Catalonia to independence. Language, law and politics are tightly connected in this matter, even if the link between them is not easy to understand precisely.Langue romane parlée par plus de 7 millions de personnes dans le monde, le catalan est un idiome historiquement issu de la continuation autochtone du latin vernaculaire en usage en Roussillon et en Catalogne. De par sa relative stabilité, ainsi que la toponymie et la phonétique le démontrent, il est le support d’une littérature très ancienne qui remonte au XIème siècle et prolifère aujourd’hui. Son aire locutoire contemporaine s’étend, au-delà de la Catalogne proprement dite, à une partie de l’Aragon, à la région de Valence et aux Baléares. Langue officielle jusqu’en 1716 sur ce territoire, et co-officielle entre 1931 et 1939, le catalan a été interdit en 1939 par une ordonnance du Général Franco. Sous le régime franquiste, le matériel d’impression des éditeurs catalanistes fut ainsi confisqué, le dictionnaire de référence saisi, la censure instaurée, et nombre de livres détruits. Mais avec le retour de la démocratie, la Catalogne a obtenu un statut de co-officialité pour le catalan, et a engagé un programme de revitalisation, fondé notamment sur l’enseignement primaire immersif dans la langue. Depuis une dizaine d’années, le statut de la langue fait l’objet d’un contentieux devant les tribunaux, et alimente une partie du discours politique, et notamment du discours nationaliste, lequel occupe aujourd’hui en Catalogne une place importante. La langue est ici liée aux revendications institutionnelles, même si ce lien n’est pas en soi consubstantiel à la simple expression linguistique

Identification of the heat input during dry or MQL machining

Machining with minimum quantity lubrication (MQL) has been the focus of many scientific investigations since the last 20 years. Nevertheless an acceptable method of predicting the thermal influences on the workpiece quality has still not been developed. This paper describes a simulation approach to estimate the distribution of the cutting energy during machining. During machining, the cutting power is measured to calculate the specific cutting power for each machining process – here drilling, tapping and milling of aluminum. In parallel, the warm-up of the part is measured by fast response thermocouples implanted closed of the machined zone. These thermocouples identify the cutting energy entering into the work piece

La Charte européenne des langues régionales ou minoritaires et la territorialité linguistique

International audienc

A study about energy consumption and cutting fluid used to clutch case machining

This paper deals with a balance of energy and cutting fluid consumption used to manufacture an aluminum clutch case (AlSi9Cu3(Fe)) in industrial context. To establish this balance sheet constitutes the first stage of a reflection aiming at reducing the economic and ecological impact of the production of mechanical parts. Indeed, before intending to set up new technologies susceptible to reduce the cost of manufacturing of a part it is necessary to draw up an inventory of fixtures of the current situation. This paper brings to light the energy and environmental cost connected to the use of cutting fluids in machining. It establishes a prerequisite in the studies necessary for the implementation of a new technology (the minimum quantity lubrication or MQL) and in the characterization of this technology in comparison with the existing (wet machining). This study joins within the framework of a project supported by the “agence de l’environnement et de la matrise de l’énergie” (ADEME, France)

Simulating the Heat Distortiion of a Cast Iron Brake Disc during Dry Machining

The application of MQL or dry machining in mass production becomes more and more accepted. Dry (MQL) machining is a very efficient solution to reduce the usage of cutting fluids and represents an effective measure for an environmental friendly production. However, these techniques do not benefit any more from the stabilization in temperature obtained with cutting fluids. More important and more heterogeneous increases of the temperature are observed. This leads to distortions of the work piece during machining which are necessary to be taken into account to maintain the geometrical quality of the manufactured surfaces. In this paper, we present a strategy to handle these thermal induced distortions in an industrial context. This strategy couples finite element thermo-elastic simulations and temperature measurements of the work piece. In a first section, we describe a method to identify machined characteristics sensible to part temperature at loading. This method takes into account standard deviation of the process. A solution to adapt tool trajectories with a temperature measurement is proposed. Second part deals with distortions of the part during manufacturing. A method is proposed to simulate distortions along machining. These FEM simulations allow to identify impact of a machining on next operations. An application of the proposed approach for the machining of a cast iron brake disc is presented. Simulations are compared to measurements made in a dry manufacturing line