10 research outputs found

    An Introduction to the \u27Oceans and Society: Blue Planet\u27 Initiative

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    We live on a blue planet, and Earth’s waters benefit many sectors of society. The future of our blue planet is increasingly reliant on the services delivered by marine, coastal and inland waters and on the advancement of effective, evidence-based decisions on sustainable development. ‘Oceans and Society: Blue Planet’ is an initiative of the Group on Earth Observations (GEO) that aims to ensure the sustained development and use of ocean and coastal observations for the benefit of society. The initiative works to advance and exploit synergies among the many observational programmes devoted to ocean and coastal waters; to improve engagement with a variety of stakeholders for enhancing the timeliness, quality and range of information delivered; and to raise awareness of the societal benefits of ocean observations at the public and policy levels. This paper summarises the role of the initiative, current activities and considerations for future directions

    Altimetry for the future: Building on 25 years of progress

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    In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the ‘‘Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

    Altimetry for the future: building on 25 years of progress

    Get PDF
    In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the “Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

    Contribution to the study of the mechanisms governing the macroscopic behaviour of stretch polymer films for industrial use

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    Les films Ă©tirables sont utilisĂ©s depuis plusieurs dĂ©cennies pour limiter le gaspillage alimentaire. Lors de leur utilisation sur des machines d'emballage industrielles, ces films sont soumis Ă  de fortes contraintes mĂ©caniques. Ils doivent Ă©galement prĂ©senter de bonnes propriĂ©tĂ©s optiques et d'adhĂ©sion. Aujourd'hui, les Ă©volutions dans le domaine de l'emballage sont trĂšs rapides. Il faut pouvoir s'adapter aux changements en termes d'approvisionnement en matiĂšres premiĂšres, mais aussi de gestion de la fin de vie. L'objectif de ce travail est de comprendre les propriĂ©tĂ©s requises pour les films en fonction de leur application et de leur fin de vie afin d'orienter le choix des matĂ©riaux et des paramĂštres de production pour obtenir des films rĂ©pondant aux attentes des consommateurs. Il a Ă©tĂ© dĂ©montrĂ© que la topologie des macromolĂ©cules a un impact non-nĂ©gligeable sur le comportement mĂ©canique des films. Il est nĂ©cessaire de prendre en compte toutes les contraintes topologiques : enchevĂȘtrements, cristaux, mais aussi liaisons intermolĂ©culaires telles que les interactions polaires formĂ©es par les EVA. L'apparition d'un blanchiment est observĂ©e Ă  partir d'un certain niveau d'allongement lorsque la cavitation est favorisĂ©e. La non-homogĂ©nĂ©itĂ© des champs de dĂ©formation des films prĂ©sentant un blanchiment a Ă©tĂ© confirmĂ©e, cependant, il n'a pas Ă©tĂ© possible d'observer directement la formation de porositĂ©s au sein des Ă©chantillons. Enfin, l'influence de diffĂ©rents facteurs tels que la dissipation d'Ă©nergie, l'inter-diffusion et la polaritĂ© sur les capacitĂ©s d'adhĂ©sion des films a Ă©tĂ© Ă©tudiĂ©e afin de cibler les amĂ©liorations possibles pour chacune des formulations existantes.Stretch films have been used for several decades to limit food waste. During their use on industrial packaging machines, these films are subjected to high mechanical stress. They must also have good optical and adhesion properties. Nowadays, developments in the field of packaging are very fast. It must be possible to adapt quickly to changes in terms of raw materials sourcing, but also end-of-life management. The aim of this work is to understand the properties required for the films depending on their application and end-of-life in order to guide the choice of materials and processing parameters to produce films that meet consumer expectations. It has been shown that the topology of the macromolecules has a non-negligible impact on the mechanical behaviour of the films. It is necessary to take into account all the topological constraints: entanglements, crystals but also intermolecular bonds such as polar interactions formed by EVAs. It appears that whitening of the film occurs at a certain elongation level when cavitation is favoured. The non-homogeneity of the deformation fields of the whitening films was confirmed, however it was not possible to directly observe the formation of porosities within the samples. Finally, the influence of different factors such as energy dissipation, interdiffusion and polarity on the adhesion capabilities of the films was studied in order to target possible improvements for each of the existing formulations

    Exploring mechanical properties of fully compostable flax reinforced composite filaments for 3D printing applications

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    Plant fibres are increasingly used for composite reinforcement, but valorization of by-products such as flax shives still needs to be developed. Also, additive manufacturing, such as Fused Deposition Modelling (FDM), is strongly progressing and can be of great interest to implement biocomposite solutions. The present work focuses on the development of innovative and fully biodegradable filaments for FDM. Three polymer matrices were tested: PLLA, PLLA/PBS 50/50%-wt and PBAT. A filler content of 30-wt% has been achieved using flax shives with PBAT. Flax fibres and shives reinforced 3D printed parts exhibit promising performances and printability, highlighting their potential to successfully develop fully compostable filaments

    Effects of Venoconstrictive Thigh Cuffs on Dry Immersion-Induced Ophthalmological Changes

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    International audienceNeuro-ophthalmological changes named spaceflight associated neuro-ocular syndrome (SANS) reported after spaceflights are important medical issues. Dry immersion (DI), an analog to microgravity, rapidly induces a centralization of body fluids, immobilization, and hypokinesia similar to that observed during spaceflight. The main objectives of the present study were 2-fold: (1) to assess the neuro-ophthalmological impact during 5 days of DI and (2) to determine the effects of venoconstrictive thigh cuffs (VTC), used as a countermeasure to limit headward fluid shift, on DI-induced ophthalmological adaptations. Eighteen healthy male subjects underwent 5 days of DI with or without VTC countermeasures. The subjects were randomly assigned into two groups of 9: a control and cuffs group. Retinal and optic nerve thickness were assessed with spectral-domain optical coherence tomography (OCT). Optic nerve sheath diameter (ONSD) was measured by ocular ultrasonography and used to assess indirect changes in intracranial pressure (ICP). Intraocular pressure (IOP) was assessed by applanation tonometry. A higher thickness of the retinal nerve fiber layer (RNFL) in the temporal quadrant was observed after DI. ONSD increased significantly during DI and remained higher during the recovery phase. IOP did not significantly change during and after DI. VTC tended to limit the ONSD enlargement but not the higher thickness of an RNFL induced by DI. These findings suggest that 5 days of DI induced significant ophthalmological changes. VTC were found to dampen the ONSD enlargement induced by DI

    An Introduction to the ‘Oceans and Society: Blue Planet’ Initiative

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    We live on a blue planet, and Earth’s waters benefit many sectors of society. The future of our blue planet is increasingly reliant on the services delivered by marine, coastal and inland waters and on the advancement of effective, evidence-based decisions on sustainable development. ‘Oceans and Society: Blue Planet’ is an initiative of the Group on Earth Observations (GEO) that aims to ensure the sustained development and use of ocean and coastal observations for the benefit of society. The initiative works to advance and exploit synergies among the many observational programmes devoted to ocean and coastal waters; to improve engagement with a variety of stakeholders for enhancing the timeliness, quality and range of information delivered; and to raise awareness of the societal benefits of ocean observations at the public and policy levels. This paper summarises the role of the initiative, current activities and considerations for future directions
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