Démarche de conception d'une cellule de parachèvement

La fonderie d'aluminium de précision par moules en sable permet de réaliser des pièces complexes de grandes dimensions et de haute technicité. Cependant les exigences industrielles en terme de sécurité et de rentabilité remettent fortement en cause la réalisation manuelle des opérations de parachèvement. Cet article décrit tout d'abord la formalisation des différentes contraintes du process de parachèvement. Nous présentons ensuite différents aspects de la démarche de conception, analyse géométrique, étude d'accessibilité, précision, rigidité, qui a abouti à la définition d'une cellule robotisée 8 axes. Les travaux actuels portent sur la gestion optimisée de la redondance cinématique afin d'améliorer le comportement global de la cellule. Celle-ci est aujourd'hui opérationnelle et l'optimisation est en cours de validation sur des pièces industrielles. Ces travaux sont réalisés en partenariat avec la Société des Fonderies d'Ussel du groupe Alcan, spécialisée dans la réalisation de pièces de haute technicité pour les secteurs aéronautiques, transport et énergie

Do Surgeons Anticipate Women’s Hopes and Fears Associated with Prolapse Repair? A Qualitative Analysis in the PROSPERE Trial

Women’s preoperative perceptions of pelvic-floor disorders may differ from those of their physicians. Our objective was to specify women’s hopes and fears before cystocele repair, and to compare them to those that surgeons anticipate. We performed a secondary qualitative analysis of data from the PROSPERE trial. Among the 265 women included, 98% reported at least one hope and 86% one fear before surgery. Sixteen surgeons also completed the free expectations-questionnaire as a typical patient would. Women’s hopes covered seven themes, and women’s fears eleven. Women’s hopes were concerning prolapse repair (60%), improvement of urinary function (39%), capacity for physical activities (28%), sexual function (27%), well-being (25%), and end of pain or heaviness (19%). Women’s fears were concerning prolapse relapse (38%), perioperative concerns (28%), urinary disorders (26%), pain (19%), sexual problems (10%), and physical impairment (6%). Surgeons anticipated typical hopes and fears which were very similar to those the majority of women reported. However, only 60% of the women reported prolapse repair as an expectation. Women’s expectations appear reasonable and consistent with the scientific literature on the improvement and the risk of relapse or complication related to cystocele repair. Our analysis encourages surgeons to consider individual woman’s expectations before pelvic-floor repair

Naturalizing Institutions: Evolutionary Principles and Application on the Case of Money

In recent extensions of the Darwinian paradigm into economics, the replicator-interactor duality looms large. I propose a strictly naturalistic approach to this duality in the context of the theory of institutions, which means that its use is seen as being always and necessarily dependent on identifying a physical realization. I introduce a general framework for the analysis of institutions, which synthesizes Searle's and Aoki's theories, especially with regard to the role of public representations (signs) in the coordination of actions, and the function of cognitive processes that underly rule-following as a behavioral disposition. This allows to conceive institutions as causal circuits that connect the population-level dynamics of interactions with cognitive phenomena on the individual level. Those cognitive phenomena ultimately root in neuronal structures. So, I draw on a critical restatement of the concept of the meme by Aunger to propose a new conceptualization of the replicator in the context of institutions, namely, the replicator is a causal conjunction between signs and neuronal structures which undergirds the dispositions that generate rule-following actions. Signs, in turn, are outcomes of population-level interactions. I apply this framework on the case of money, analyzing the emotions that go along with the use of money, and presenting a stylized account of the emergence of money in terms of the naturalized Searle-Aoki model. In this view, money is a neuronally anchored metaphor for emotions relating with social exchange and reciprocity. Money as a meme is physically realized in a replicator which is a causal conjunction of money artefacts and money emotions

Early Stopping in Global Data Computation

http://doi.ieeecomputersociety.org/10.1109/TPDS.2003.1233713International audienceThe Global Data Computation problem consists of providing each process with the same vector (with one entry per process) such that each entry is filled by a value provided by the corresponding process. This paper presents a protocol that solves this problem in an asynchronous distributed system where processes can crash, but equipped with a perfect failure detector. This protocol requires that processes execute asynchronous computation rounds. The number of rounds is upper bounded by min(f + 2, t + 1, n), where n, t, and f represent the total number of processes, the maximum number of processes that can crash, and the number of processes that actually crash, respectively. This value is a lower bound for the number of rounds when t < n - 1. To our knowledge, this protocol is the first to achieve this lower bound. Interestingly, this protocol meets the same lower bound as the one required in synchronous systems

Early Stopping in Global Data Computation

http://doi.ieeecomputersociety.org/10.1109/TPDS.2003.1233713International audienceThe Global Data Computation problem consists of providing each process with the same vector (with one entry per process) such that each entry is filled by a value provided by the corresponding process. This paper presents a protocol that solves this problem in an asynchronous distributed system where processes can crash, but equipped with a perfect failure detector. This protocol requires that processes execute asynchronous computation rounds. The number of rounds is upper bounded by min(f + 2, t + 1, n), where n, t, and f represent the total number of processes, the maximum number of processes that can crash, and the number of processes that actually crash, respectively. This value is a lower bound for the number of rounds when t < n - 1. To our knowledge, this protocol is the first to achieve this lower bound. Interestingly, this protocol meets the same lower bound as the one required in synchronous systems

Cellule de parachèvement pour pièce de fonderie de grandes dimensions

L’obtention de pièces structurales en fonderie sable aluminium de haute technicité nécessite un processus de parachèvement conséquent comprenant la découpe du système de coulée, suivie d’un ponçage quasi global des surfaces. Les exigences industrielles en termes de sécurité et de rentabilité remettent fortement en cause la réalisation manuelle de ces opérations. Cet article présente le développement d’une nouvelle cellule robotisée pour ce parachèvement, mené en collaboration avec La Société des Fonderies d’Ussel (SFU) du groupe ALCAN. La première partie est consacrée à la caractérisation des contraintes liées aux spécifications fonctionnelles attendues sur la pièce et aux procédés d’usinage et de ponçage. Ceci a abouti à la définition d’une cellule redondante 8 axes pour répondre au critère d’espace de travail et intégrant un robot à structure hybride (Tricept) pour ses capacités à réaliser les opérations d’usinage en conditions UGV et de ponçage. La deuxième partie porte sur la définition de critères pour une gestion optimisée des redondances en vue d’améliorer le comportement global de la cellule et répondre aux exigences de précision et de capacité cinématique. La dernière partie présente l’optimisation mise en œuvre et les résultats validés sur un ensemble de pièces

Inflamatory response to cold plasma in normal skin

International audienceAim Investigate the effect of dose of cold plasma on skin integrity.Background Cold plasma is an emerging novel therapeutic approach in medicine with a great potential in auto-immune skin disorders, cutaneous infections and tumors. Only limited data are available on the safety of such a therapy. Therefore we investigated the cutaneous response in mice exposed to cold plasma.Methods We used BL6 mice which were exposed to plasma DBD (dielectric barrier discharge) in air at 2 mm of the skin for increasing doses to define the threshold of safety. The skin was excised at 24h and analyzed for integrity, neutrophil recruitment and cytokine and chemokine production and histological analyses.Results A dose dependent reddening of the skin was observed with scales at the highest dose. The macroscopic changes correlated with increased neutrophil recruitment in the skin as assessed by myeloperoxidase (MPO) activity, microscopically neutrophil infiltration of the epidermis extending in the dermis and at the highest dose in the subcutaneous fat tissue. Further, microabcesses in the epidermis with necrosis were found at the highest exposure dose. The measurement of inflammatory cytokines and chemokines associated with the inflammatory response is ongoing.The effect of high dose plasma was comparable to a local intradermal injection of endotoxin in terms of neutrophils infiltration.We hypothesized that epidermal barrier was damaged by the plasma allowing the entrance of commensals and their products into skin resulting in TLR depending activation of the innate immunity and inflammation. To test this hypothesis, we have ongoing studies using TLR2-4 and IL-1R deficient mice, which may have attenuated inflammation.In conclusion, a safe dose of plasma needs to be defined which conserves the epidermal integrity and avoids an inflammatory response

Modelling migration from high-density polyethylene containers into concentrated solutions used as food flavourings

peer reviewedMigration from high-density polyethylene into different liquids (hexane, ethanol, lemon terpenes and their emulsions) was modelled using the response surfaces method. Polynomial equations (z = A + Bx + Cy + Dx(2) + Ey(2) + Fxy) were established and parameters determined for each compound. Correlation coefficients were generally > 90%. Analysis indicated that 2,4-bis(1,1-dimethylethyl) phenol, probably due to the degradation of the antioxidant additive tris(2,4- bis(1,1-dimethylethyl) phenyl) phosphite, migrated into each liquid tested, whatever the temperature. Oligomers (10-30 carbons) terminated by a vinyl group were also detected

Assessment of lipoxygenase activity in seed extracts from 35 plant species

Lipoxyganase activity in 35 seed extracts was determined an the basis of hydroperoxide synthesis using linoleic acid as substrate. The results referring to the extracted protein content show that several species of Vigna (V. unguiculata, V. radiata and V. mungo) and one of Trifolium exhibit stronger lipoxygenase activity than soybean enzyme extracts. The pH-activity relationship was also established for 4 very active samples. GCMS analysis revealed equal amounts of 9- and 13 hydroperoxides of linoleic acid In these seed extracts, indicating no enzyme positional specificity