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| Registros recuperados: 10 | |
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| Maisondieu, Christophe; Forest, Bertrand. |
| The SAR-DRIFT project aims at developing a forecast system for localisation of drifting objects, as well as decision aid tools for Maritime Search and Rescue. Its basic principle is to predict the position of drifting objects, when combining environmental measurements and forecast through sophisticated stochastic modelling. Among the different tasks of the project, one is to assess the hydrodynamic behaviour of various objects drifting at sea when submitted to the joint action of wind, waves and currents. Thousands of cargo containers are reported to fall overboard each year. A significant part of these containers will stay afloat from several hours to several weeks and represent a major hazard to navigation. In order to evaluate the drift coefficients of... |
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| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/00238/34970/33472.pdf |
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| Delauney, Laurent; Boukerma, Kada; Bucas, Karenn; Coail, Jean-yves; Debeaumont, Mathieu; Forest, Bertrand; Garello, Celia; Guyader, Gerard; Le Bras, Yves; Peleau, Michel; Rinnert, Emmanuel. |
| Oceans environmental monitoring and seafloor exploitation need in situ sensors and optical devices (cameras, lights) in various locations and on various carriers in order to initiate and to calibrate environmental models or to operate underwater industrial process supervision. For more than 10 years Ifremer deploys in situ monitoring systems for various seawater parameters and in situ observation systems based on lights and HD Cameras. To be economically operational, these systems must be equipped with a biofouling protection dedicated to the sensors and optical devices used in situ. Indeed, biofouling, in less than 15 days [1] will modify the transducing interfaces of the sensors and causes unacceptable bias on the measurements provided by the in situ... |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00349/45998/45667.pdf |
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| Tassin, Alan; Breton, Thibaut; Forest, Bertrand; Ohana, Jeremy; Chalony, Sebastien; Le Roux, Dominique; Tancray, Aurelien. |
| We investigate experimentally the time evolution of the wetted surface during the lifting of a body initially floating at the water surface. This phenomenon is referred to as the water exit problem. The water exit experiments were conducted with transparent (PMMA) mock-ups of two different shapes: a circular disc and a square flat plate. Two different lighting systems were used to diffuse light in the mock-up material: a central high-power LED light normal to the surface and an edge-lighting system featuring an array of LED lights. These setups make it possible to illuminate the contact line, which delimits the surface of contact between the mock-up and the water. The characteristic size of the mock-ups is about 20 cm and the acceleration of the mock-up... |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00392/50315/51074.pdf |
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| Festy, Dominique; Forest, Bertrand; Keddam, M.; Marchal, R.; Monfort Moros, N.; Tribollet, B.. |
| The biofilm developing on carbon steel surfaces in anaerobic condition may induce localised corrosion. To be able to better understand this type of biocorrosion, this paper presents a new electrochemical technique, which has been developed in collaboration between IFREMER and the Laboratory for liquid physic and electrochemistry. Focussed on local aspect of this phenomenon, the described technique enables surface current density mapping to be performed and anodic or cathodic zones to be identified. A double microelectrode probe is placed closed to the steel sample surface and potential difference between them is measured. This value is directly connected to ohmic drop within electrolyte and consequently, to local current. By scanning the substrate surface,... |
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| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00480/59140/61768.pdf |
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| Derombise, Guillaume; Chailleux, Emmanuel; Forest, Bertrand; Riou, Luc; Lacotte, Nicolas; Van Schoors, L. Vouyovitch; Davies, Peter. |
| Aramid fibers are today proposed in ropes and cables for marine applications. As these highly crystalline materials are loaded in tension for a longer period in seawater, their long-term mechanical behavior has to be understood. However, the response is time-dependent and exhibits a nonlinear effect with stress. In this study, two types of aramid fibers are studied: Twaron and Technora. Mechanical properties are measured using static tensile tests and creep-recovery tests. A nonlinear viscoelastic-viscoplastic model, based on the Schapery formulation, allows discriminating between the instantaneous and the time-dependent response as well as the reversible and nonreversible phenomena (plasticity). First, this procedure allows the overall mechanical behavior... |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00039/15049/12604.pdf |
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| Colas, Florent; Tardivel, Morgan; Evrard, Justine; Forest, Bertrand; Crassous, Marie-pierre; Lunven, Michel; Danielou, Marie-madeleine. |
| This deliverable contains all development work of the FastCAM, new tool for fast imaging of the phytoplankton, which took place in 2015. It consists of: One report of the FastCAM and its comparison with the FlowCAM presentation: The FlowCAM enables the digitalization of a sample of phytoplankton with X10 and X 4 magnifications. The first allows a better morphological description and therefore a higher taxonomic resolution but with a longer scan time (16 X). Thus, for routine analyses, only scanning at 4 X is possible. A considerable gain would be able to do an acquisition to the magnification 10 X with a time of analysis more short, comparable to 4 X. A fast flow imaging system has therefore developed in this sense. He was called FastCAM. The system is... |
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Palavras-chave: FlowCAM; FastCAM; Imagerie rapide; Phytoplancton; REPHY.; FlowCAM; FastCAM; Fast imaging; Phytoplankton; REPHY. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00363/47420/47425.pdf |
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| Colas, Florent; Tardivel, Morgan; Perchoc, Jonathan; Lunven, Michel; Forest, Bertrand; Guyader, Gerard; Danielou, Marie-madeleine; Le Mestre, Sophie; Bourriau, Paul; Antajan, Elvire; Sourisseau, Marc; Huret, Martin; Petitgas, Pierre; Romagnan, Jean-baptiste. |
| In this paper we present the ZooCAM, a system designed to digitize and analyse on board large volume samples of preserved and living metazooplankton (i.e. multicellular zooplankton) and fish eggs > 300 µm ESD. The ZooCAM has been specifically designed to overcome the difficulties to analyse zooplankton and fish eggs in the framework of the PELGAS survey, and provide high frequency data. The ZooCAM fish eggs counts were comparable to those done with a dissecting microscope. The ZooCAM enabled the accurate prediction and fast on board validation of staged anchovy and sardine eggs in almost real time after collection. A comparison with the ZooScan, on a more complex zooplanktonic community, provided encouraging results on the agreement between the 2... |
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Palavras-chave: ZooCAM; In-flow imaging; Fish eggs; Zooplankton; Ecosystemic survey. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00407/51833/52432.pdf |
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| Registros recuperados: 10 | |
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