Energy and director switches commutation controls for the alternate arm converter

The Alternate Arm Converter (AAC) is promising multilevel Voltage Source Converter (VSC) suitable for High Voltage Direct Current (HVDC) transmission systems. This converter exhibits interesting features such as a DC Fault Ride Through capability thanks to the use of Full-Bridge Sub-Modules (SM) and a smaller footprint than an equivalent Modular Multilevel Converter (MMC). After an analysis of the converter operating modes called Non-overlap and Overlap mode, a sequential representation of the AAC operation is proposed. The main originality of this paper is the use of the Petri Net to describe all the phases and to highlight their sequencing. According to the phases identified thanks to the sequential approach, models and control structures for the grid currents, the internal energy and the Zero Current Switching (ZCS) are detailed. Furthermore, the step-by-step approach proposed in this paper allows a clear and rigorous modelling of this complex converter

Impact of oil on bacterial community structure in bioturbated sediments

Oil spills threaten coastlines where biological processes supply essential ecosystem services. Therefore, it is crucial to understand how oil influences the microbial communities in sediments that play key roles in ecosystem functioning. Ecosystems such as sediments are characterized by intensive bioturbation due to burrowing macrofauna that may modify the microbial metabolisms. It is thus essential to consider the bioturbation when determining the impact of oil on microbial communities. In this study, an experimental laboratory device maintaining pristine collected mudflat sediments in microcosms closer to true environmental conditions - with tidal cycles and natural seawater - was used to simulate an oil spill under bioturbation conditions. Different conditions were applied to the microcosms including an addition of: standardized oil (Blend Arabian Light crude oil, 25.6 mg.g21 wet sediment), the common burrowing organism Hediste (Nereis) diversicolor and both the oil and H. diversicolor. The addition of H. diversicolor and its associated bioturbation did not affect the removal of petroleum hydrocarbons. After 270 days, 60% of hydrocarbons had been removed in all microcosms irrespective of the H. diversicolor addition. However, 16S-rRNA gene and 16S-cDNA T-RFLP and RT-PCR-amplicon libraries analysis showed an effect of the condition on the bacterial community structure, composition, and dynamics, supported by PerMANOVA analysis. The 16S-cDNA libraries from microcosms where H. diversicolor was added (oiled and un-oiled) showed a marked dominance of sequences related to Gammaproteobacteria. However, in the oiled-library sequences associated to Deltaproteobacteria and Bacteroidetes were also highly represented. The 16S-cDNA libraries from oiled-microcosms (with and without H. diversicolor addition) revealed two distinct microbial communities characterized by different phylotypes associated to known hydrocarbonoclastic bacteria and dominated by Gammaproteobacteria and Deltaproteobacteria. In the oiled-microcosms, the addition of H. diversicolor reduced the phylotype-richness, sequences associated to Actinobacteria, Firmicutes and Plantomycetes were not detected. These observations highlight the influence of the bioturbation on the bacterial community structure without affecting the biodegradation capacities

De la production à l’usage de la mesure, quelle appropriation par deux entreprises industrielles ? Pour quelle prévention des TMS ?

This paper, produced from interventions conducted over several years in two industrial companies, namely a large manufacturing company in the automotive sector and an SME in the pharmaceutical sector, provides feedback on the generation and use of measurements in MSD prevention. After an introduction to the problem and a quick presentation of MSD prevention using the Muska®MSD tool, we analyzed the research feedback based on its impacts in terms of adaptation in the two companies. We compared how they incorporated the generation and the use of measurements through the Muska®MSD tool based on four criteria identified as necessary for sustainable MSD prevention. Finally, we concluded with the roles allocated to the generation and use of measurements so as to ensure sustainable MSD prevention

De l'outil Muska à la démarche de prévention des TMS, quelles appropriations ?: Comparaison entre une PME et une grande entreprise

Atelier 7 : Adaptation et appropriation des outils au service de la prévention des TMSMuska est un logiciel d'évaluation et de simulation du risque TMS. Dans le cadre d'une démarche de prévention globale, cet outil permet de disposer de données quantifi ées issues d'observations de l'activité de travail dans le but de faciliter l'objectivation de l'exposition aux TMS, la recherche et l'appropriation de solutions. Développé et expérimenté en Aquitaine, la diffusion au niveau national de Muska par l'Anact répond à la nécessité d'aider les entreprises à évaluer le risque de survenue de TMS, et à mettre en oeuvre des démarches de prévention durable. Cette communication se centre sur la comparaison de deux exemples d'appropriation de Muska dans des contextes différents : une grande entreprise manufacturière du secteur automobile et une PME du secteur pharmaceutique. Nous aborderons dans un premier temps les caractéristiques de ces entreprises et leurs conséquences en termes d'adaptation du dispositif de transfert. Comment la taille de l'entreprise, le secteur d'activité, le système de management de la santé et sécurité, les compétences internes et leurs disponibilités vont influer sur les objectifs poursuivis et les moyens mis en oeuvre, à la fois par l'entreprise et par l'intervenant ? Dans un deuxième temps, nous comparerons l'appropriation de Muska par ces deux entreprises au travers de quatre critères identifiés comme nécessaires pour favoriser une prévention durable des TMS : - la démarche de prévention mise en oeuvre sous forme de conduite de projet ; - les connaissances et compétences d'analyse du travail et en particulier de l'activité ; - l'utilisation de l'outil Muska pour mesurer et évaluer les risques de TMS ; - l'évolution du projet de prévention des TMS dans le temps. Ces quatre critères posent les questions de la participation et de la formation des acteurs de la démarche, mais également du transfert de compétences aux organisateurs et concepteurs des situations de travail afi n que ceux-ci tiennent compte de la prévention de la santé au-delà de la performance de l'entreprise. Nous conclurons sur le rôle de Muska dans la pérennisation des démarches de prévention des TMS : quels avantages ? quelles limites

Effects of oil exposure and dispersant use upon environmental adaptation performance and fitness in the European sea bass, Dicentrarchus labrax.

International audienceThe worldwide increasing recourse to chemical dispersants to deal with oil spills in marine coastal ecosystems is a controversial issue. Yet, there exists no adequate methodology that can provide reliable predictions of how oil and dispersant-treated oil can affect relevant organism or population-level performance. The primary objective of the present study was to examine and compare the effects of exposure to untreated oil (weathered Arabian light crude oil), chemically dispersed oil (Finasol, TOTAL-Fluides) or dispersant alone, upon the ability of fish for environmental adaptation. To reach that goal, we implemented high-throughput, non-lethal challenge tests to estimate individual hypoxia and heat tolerance as surrogate measures of their capacity to face natural contingencies. Experimental populations were then transferred into semi-natural tidal ponds and correlates of individuals' fitness (growth and survival) were monitored over a period of 6 months. In accordance with our stated objectives, the contamination conditions tested corresponded to those observed under an oil slick drifting in shallow waters. Our results revealed that the response of control fish to both challenges was variable among individuals and temporally stable (repeatable) over a 2-month period. Exposure to chemical dispersant did not affect the repeatability of fish performance. However, exposure to oil or to a mixture of oil plus dispersant affected the repeatability of individuals' responses to the experimental challenge tests. At population level, no difference between contamination treatments was observed in the distribution of individual responses to the hypoxia and temperature challenge tests. Moreover, no correlation between hypoxia tolerance and heat tolerance was noticed. During the field experiment, hypoxia tolerance and heat tolerance were found to be determinants of survivorship. Moreover, experimental groups exposed to oil or to dispersant-treated oil displayed significantly lower survival than control or dispersant-exposed groups. Finally, from the four experimental populations tested, the one exposed to chemically dispersed oil presented the lowest growth rate

Adoption des articles 22 et 23 du titre II du projet de décret sur les droits féodaux, lors de la séance du 5 mars 1790

Merlin de Douai, Montesquiou Fezensac François Xavier, abbé et duc de. Adoption des articles 22 et 23 du titre II du projet de décret sur les droits féodaux, lors de la séance du 5 mars 1790. In: Archives Parlementaires de 1787 à 1860 - Première série (1787-1799) Tome XII - Du 2 mars au 14 avril 1790. Paris : Librairie Administrative P. Dupont, 1881. p. 36

Adoption des articles 22 et 23 du titre II du projet de décret sur les droits féodaux, lors de la séance du 5 mars 1790

Merlin de Douai Philippe Antoine, Montesquiou Fezensac François Xavier, abbé et duc de. Adoption des articles 22 et 23 du titre II du projet de décret sur les droits féodaux, lors de la séance du 5 mars 1790. In: Archives Parlementaires de 1787 à 1860 - Première série (1787-1799) sous la direction de Jérôme Mavidal et Emile Laurent. Tome XII - Du 2 mars au 14 avril 1790. Paris : Librairie Administrative P. Dupont, 1881. p. 36

Lecture du procès verbal de la séance du 10 mars 1790, lors de la séance du 11 mars 1790

Montesquiou Fezensac François Xavier, abbé et duc de, Merlin de Douai, Guillaume Louis-Marie. Lecture du procès verbal de la séance du 10 mars 1790, lors de la séance du 11 mars 1790. In: Archives Parlementaires de 1787 à 1860 - Première série (1787-1799) Tome XII - Du 2 mars au 14 avril 1790. Paris : Librairie Administrative P. Dupont, 1881. pp. 115-116