Chaining of welding and finish turning simulations for austenitic stainless steel components

The chaining of manufacturing processes is a major issue for industrials who want to understand and control the quality of their products in order to ensure their in-service integrity (surface integrity, residual stresses, microstructure, metallurgical changes, distortions,…). Historically, welding and machining are among the most studied processes and dedicated approaches of simulation have been developed to provide reliable and relevant results in an industrial context with safety requirements. As the simulation of these two processes seems to be at an operationnal level, the virtual chaining of both must now be applied with a lifetime prediction prospect. This paper will first present a robust method to simulate multipass welding processes that has been validated through an international round robin. Then the dedicated “hybrid method”, specifically set up to simulate finish turning, will be subsequently applied to the welding simulation so as to reproduce the final state of the pipe manufacturing and its interaction with previous operations. Final residual stress fields will be presented and compared to intermediary results obtained after welding. The influence of each step on the final results will be highlighted regarding surface integrity and finally ongoing validation works and numerical modeling enhancements will be discussed

First results on the diet of the young Atlantic sturgeon Acipenser sturio L., 1758 in the Gironde estuary

Very little is known about the diet of the European sturgeon Acipenser sturio L., 1758 in its natural environment. For juveniles, improved knowledge in this field could lead towards the determination of the species's major feeding habitats in the estuary, in order to then improve their preservation or protection. From May 1998 to March 1999, the stomach contents of 61 juveniles were collected by gastric lavage. The fish were caught during monthly trawling campaigns to monitor sturgeon migration in the Gironde estuary (southwestern France). Specimens were mainly caught during spring and summer in two areas of increased abundance. The gastric lavage method used had been previously tested on Siberian sturgeon Acipenser baerii Brandt, 1869 in captivity. Twelve taxa of prey were found. The highest proportions in number identified consisted of polychaetes, mainly represented by Heteromastus filiformis (Claparede, 1864) in zone 7 and Polydora Bosc, 1802 sp. in zone 1. Crustaceans were the second most abundant group of prey.Se conoce muy poco sobre la dieta del esturión atlántico Acipenser sturio L., 1758 en su medio natural. Para los juveniles, un conocimiento mejorado en este campo podía conducir hacia la determinación de los principales hábitats alimentarios de la especie en el estuario, como preámbulo para su mejor preservación y conservación. Entre mayo de 1998 y marzo de 1999 fueron recogidos los contenidos estomacales de 61 juveniles por lavado gástrico. Los peces fueron capturados durante las campañas mensuales de pesca de arrastre para el seguimiento de la migración del esturión en el estuario del Gironda (suroeste de Francia). Los ejemplares fueron capturados principalmente en primavera y verano en dos áreas de alta abundancia. El método de lavado gástrico utilizado fue probado previamente en cautividad con esturión siberiano Acipenser baerii Brandt, 1869. Se encontraron presas de doce taxones. Las proporciones más altas en número correspondieron a poliquetos, principalmente representados por Heteromastus filiformis (Claparede, 1864) en la zona 7 y Polydora Bosc, 1802 sp. en la zona 1. Los crustáceos fueron el segundo grupo de presas más abundante.Instituto Español de Oceanografí

MADES FP7 EU project: Effective high level SysML/MARTE methodology for real-time and embedded avionics systems

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Machine-Part cell formation through visual decipherable clustering of Self Organizing Map

Machine-part cell formation is used in cellular manufacturing in order to process a large variety, quality, lower work in process levels, reducing manufacturing lead-time and customer response time while retaining flexibility for new products. This paper presents a new and novel approach for obtaining machine cells and part families. In the cellular manufacturing the fundamental problem is the formation of part families and machine cells. The present paper deals with the Self Organising Map (SOM) method an unsupervised learning algorithm in Artificial Intelligence, and has been used as a visually decipherable clustering tool of machine-part cell formation. The objective of the paper is to cluster the binary machine-part matrix through visually decipherable cluster of SOM color-coding and labelling via the SOM map nodes in such a way that the part families are processed in that machine cells. The Umatrix, component plane, principal component projection, scatter plot and histogram of SOM have been reported in the present work for the successful visualization of the machine-part cell formation. Computational result with the proposed algorithm on a set of group technology problems available in the literature is also presented. The proposed SOM approach produced solutions with a grouping efficacy that is at least as good as any results earlier reported in the literature and improved the grouping efficacy for 70% of the problems and found immensely useful to both industry practitioners and researchers.Comment: 18 pages,3 table, 4 figure

Effect of Grain Boundary Character Distribution on the Impact Toughness of 410NiMo Weld Metal

Grain boundary character distributions in 410NiMo weld metal were studied in the as-welded, first-stage, and second-stage postweld heat treatment (PWHT) conditions, and these were correlated with the Charpy-V impact toughness values of the material. The high impact toughness values in the weld metal in the as-welded and first-stage PWHT conditions compared to that in the second-stage condition are attributed to the higher fraction of low-energy I pound boundaries. A higher volume fraction of retained austenite and coarser martensite after second-stage PWHT accompanied by the formation of the ideal cube component in the 2-hour heat-treated specimen led to a reduction in the toughness value. A subsequent increase in the PWHT duration at 873 K (600 A degrees C) enhanced the formation of {111}aOE (c) 112 >, which impedes the adverse effect of the cubic component, resulting in an increase in the impact toughness. In addition to this, grain refinement during 4-hour PWHT in the second stage also increased the toughness of the weld metal

METSTOR: A GIS to look for potential CO2 storage zones in France

AbstractThe METSTOR project offers a methodology to look for potentially interesting CO2 storage areas in France at the initial stage, before the “site selection” step. Our tool, embodied in a Geographic Information System, is based on an interactive map of CO2 storage capacities. Other relevant information layers are included. The geographic layers are complemented with a series of online technical notices. It seems to be the first open online GIS that offers policy makers, businesses and the public at large an integrated access to that necessary information. Our prototype, limited mainly to the Paris Basin, is released online at www.metstor.fr

Erosion of global functional diversity across the tree of life

Although one-quarter of plant and vertebrate species are threatened with extinction, little is known about the potential effect of extinctions on the global diversity of ecological strategies. Using trait and phylogenetic information for more than 75,000 species of vascular plants, mammals, birds, reptiles, amphibians, and freshwater fish, we characterized the global functional spectra of each of these groups. Mapping extinction risk within these spectra showed that larger species with slower pace of life are universally threatened. Simulated extinction scenarios exposed extensive internal reorganizations in the global functional spectra, which were larger than expected by chance for all groups, and particularly severe for mammals and amphibians. Considering the disproportionate importance of the largest species for ecological processes, our results emphasize the importance of actions to prevent the extinction of the megabiota

Linking human impacts to community processes in terrestrial and freshwater ecosystems

Human impacts such as habitat loss, climate change and biological invasions are radically altering biodiversity, with greater effects projected into the future. Evidence suggests human impacts may differ substantially between terrestrial and freshwater ecosystems, but the reasons for these differences are poorly understood. We propose an integrative approach to explain these differences by linking impacts to four fundamental processes that structure communities: dispersal, speciation, species-level selection and ecological drift. Our goal is to provide process-based insights into why human impacts, and responses to impacts, may differ across ecosystem types using a mechanistic, eco-evolutionary comparative framework. To enable these insights, we review and synthesise (i) how the four processes influence diversity and dynamics in terrestrial versus freshwater communities, specifically whether the relative importance of each process differs among ecosystems, and (ii) the pathways by which human impacts can produce divergent responses across ecosystems, due to differences in the strength of processes among ecosystems we identify. Finally, we highlight research gaps and next steps, and discuss how this approach can provide new insights for conservation. By focusing on the processes that shape diversity in communities, we aim to mechanistically link human impacts to ongoing and future changes in ecosystems

Linking human impacts to community processes in terrestrial and freshwater ecosystems.

Human impacts such as habitat loss, climate change and biological invasions are radically altering biodiversity, with greater effects projected into the future. Evidence suggests human impacts may differ substantially between terrestrial and freshwater ecosystems, but the reasons for these differences are poorly understood. We propose an integrative approach to explain these differences by linking impacts to four fundamental processes that structure communities: dispersal, speciation, species-level selection and ecological drift. Our goal is to provide process-based insights into why human impacts, and responses to impacts, may differ across ecosystem types using a mechanistic, eco-evolutionary comparative framework. To enable these insights, we review and synthesise (i) how the four processes influence diversity and dynamics in terrestrial versus freshwater communities, specifically whether the relative importance of each process differs among ecosystems, and (ii) the pathways by which human impacts can produce divergent responses across ecosystems, due to differences in the strength of processes among ecosystems we identify. Finally, we highlight research gaps and next steps, and discuss how this approach can provide new insights for conservation. By focusing on the processes that shape diversity in communities, we aim to mechanistically link human impacts to ongoing and future changes in ecosystems

Exercise and Pharmacotherapy in the Treatment of Major Depressive Disorder

To assess whether patients receiving aerobic exercise training performed either at home or in a supervised group setting achieve reductions in depression comparable to standard antidepressant medication (sertraline) and greater reductions in depression compared to placebo controls