13 research outputs found

    Les submersions de tempête de la nuit du 10 au 11 mars 2008 sur la côte d’Albâtre (Haute-Normandie, France) : détermination météo-marine

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     Plus que l’analyse de l’impact morpho-sédimentaire sur les plages de galets haut-normandes de la tempête du 10 au 10 mars 2008, l’objet de cet article est de présenter les caractéristiques météo-marines en cause et leurs interactions éventuelles dans le processus des submersions qui ont affecté la côte d’Albâtre. Quelques éléments d’information qualitative concernant l’ajustement morpho-sédimentaire spécifique des plages de galets anthropisées à ce type de forçage seront fournis. En effet, la tempête du 10 au 11 mars n’a pas fait l’objet de mesures morpho-sédimentaires spécifiques, mais visuellement, correspond en tout point à ce qui a pu être mesuré sur les plages haut-normandes lors de campagnes récentes réalisées avant et après tempête. L’étude se concentre sur le secteur de Dieppe, qui bénéficie d’un marégraphe (implanté dans l’avant-port de Dieppe) et d’un poste de mesures météorologiques situé au sémaphore de la Marine nationale, sous maintenance de Météo-France, et permettant notamment l’analyse de « données minute ». Cette étude révèle que les facteurs d’ordre purement météorologique qui ont abouti aux submersions de la nuit du 10 au 11 mars n’étaient pas de nature extrême, et que c’est la complexité des interactions en cause (conditions météorologiques de surface et d’altitude, morpho-sédimentaires et surtout marégraphiques et houlographiques), qui permet de comprendre l’ampleur de certaines inondations. Un « forçage » météorologique plus violent sur ces interactions, tel que celui observé le 17 décembre 2004, qui eut peu de conséquence en raison d’un faible coefficient de marée (71), pourrait aboutir à des submersions beaucoup plus sévères sur des sites urbanisés dont l’altitude et est parfois égale, voire inférieure à celle des pleines mers de vive eau.More than the analysis of the morpho-sedimentary impact on Haute-Normandie gravel beaches during the storm of March 10th-11st 2008, the aim of this paper is to present meteorological and marine characteristics and their possible interactions in the process of storm surges which affected the « côte d’Albâtre ». Some elements of qualitative information concerning the specific morpho-sedimentary adjustment of these anthropized gravel beaches face to this meteorological forcing will be provided. Indeed, the storm of March 10th-11st 2008 was not subjected to specific morpho-sedimentary measurements but visually fits with the measurements taken on Haute-Normandie beaches during recent surveys executed before and after storm. This study focuses on the Dieppe area, which has a tide gauge (located in the outer port of Dieppe) and a meteorological measurement post, located at the national Navy semaphore, under the servicing of Meteo-France, and allowing analysis of « minute-data ». This study reveals that meteorological factors, ending in storm surges during the night of March 10th-11st, were not of extreme nature, and that it is the complexity of interactions (surface and altitude meteorological conditions, morpho-sedimentary and especially tidal and wave conditions) that allows an understanding of the extent of several floodings. A more violent meteorological « forcing » on these interactions, such as during December 17th 2004, that had few consequences because of low tidal coefficient (71), would end in much more important storm surges

    Aspects météo-marins de la tempête du 10 mars 2008 en Atlantique et en Manche

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    Le 10 mars 2008, une tempête a touché la pointe nord-ouest de l’Europe pendant une marée de vive-eau, générant de nombreux dégâts et des cas de submersion sur les côtes nord-ouest de la France. Les niveaux d’eau exceptionnels atteints ce jour-là sont dus à la combinaison de deux phénomènes indépendants (surcote importante accompagnée d’une mer énorme et pleine mer de vive-eau). Les niveaux d’eau maximums à l’origine de la submersion des côtes basses ont été à chaque fois précédés par le passage d’un front froid. Les vitesses de vent et les hauteurs de houles atteintes pendant cette tempête ont une période de retour de deux ans. Les niveaux d’eau mesurés par les marégraphes ont une occurrence de deux à cent ans. Il est en revanche impossible d’estimer pour le moment la période de retour de la combinaison houle – surcote – pleine mer de vive-eau, mais elle est probablement de l’ordre de 10 ans ou plus.The 10th of March 2008, a storm reached north-western of Europe during a spring tide, generating many damages and coastal flooding on the north-western french coast. The extrem water levels recorded on that day are caused by a combinaison of independant phenomena (important storm surge, phenomenal waves, spring high tide). The maximum water levels and most coastal flooding were every time linked with a cold front. Wind speed and wave height reached during this storm have a return period of only two years. The water levels mesured by tidal gauges have a return period from two to hundred years. Nevertheless it is impossible for the moment to estimate the return period of the combinaison wave – surge – spring high tide, but it is likely of the order of ten years or more

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    Study of the assumptions to obtain a technologically and economically viable decarbonised ammonia and steelmaking plant

    Feasibility study of low-carbon ammonia and steel production in Europe

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    peer reviewedAs stipulated in the Paris Agreement, greenhouse gas emissions have to be reduced in order to maintain the global warming well below 2°C. Moreover, the European Union committed to become carbon neutral by 2050. This will require shifting industrial production currently based on fossil energies towards the use of renewable energies. The present article considers two conceptual industrial processes that may operate in Europe with low carbon emissions through the use of green hydrogen. The studied processes are projections of the production of ammonia and steel in the 2030s. Hydrogen is assumed to be produced by water electrolysis with Proton Exchange Membrane electrolysers. The purpose of this paper being to evaluate the feasibility of such processes, it is assumed that the electricity required by the processes is entirely provided by renewable energies, in order to focus only on the challenges directly related to the ammonia and steelmaking plants. For the same reason, the prices are estimated in 2030 and not later, to avoid too uncertain costs assumptions, even if a complete supply by renewable energies may be unrealistic at that moment. Based on current industrial sectors of both ammonia and steel productions, a detailed modelling of the two decarbonised processes in Aspen Plus software is carried out and an economic analysis is also presented to prove the feasibility of these processe

    Interaction between hormone-sensitive lipase and ChREBP in fat cells controls insulin sensitivity.

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    Impaired adipose tissue insulin signalling is a critical feature of insulin resistance. Here we identify a pathway linking the lipolytic enzyme hormone-sensitive lipase (HSL) to insulin action via the glucose-responsive transcription factor ChREBP and its target, the fatty acid elongase ELOVL6. Genetic inhibition of HSL in human adipocytes and mouse adipose tissue results in enhanced insulin sensitivity and induction of ELOVL6. ELOVL6 promotes an increase in phospholipid oleic acid, which modifies plasma membrane fluidity and enhances insulin signalling. HSL deficiency-mediated effects are suppressed by gene silencing of ChREBP and ELOVL6. Mechanistically, physical interaction between HSL, independent of lipase activity, and the isoform activated by glucose metabolism ChREBPα impairs ChREBPα translocation into the nucleus and induction of ChREBPβ, the isoform with high transcriptional activity that is strongly associated with whole-body insulin sensitivity. Targeting the HSL-ChREBP interaction may allow therapeutic strategies for the restoration of insulin sensitivity
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