2,345 research outputs found

    Rapport de la campagne Equalis à bord du NO Alis pendant la période d'observations intensives de l'opération Coare du 3 novembre au 12 décembre 1992

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    La campagne océanographique EQUALIS est une opération commune aux programmes internationaux JGOFS (Joint Global Ocean Flux Study) et TOGA-COARE (Tropical Ocean and Global Atmosphere - Coupled Ocean Atmosphere Response Experiment) organisée par le groupe FLUPAC (Flux dans l'Ouest du Pacifique Equatorial) du Centre ORSTOM de Nouméa, Nouvelle-Calédonie, avec la participation ou la collaboration de chercheurs japonais et australiens. Elle a eu lieu du 3 novembre au 12 décembre 1992 à bord du navire océanographique de l'ORSTOM, l' ALIS, et a consisté en deux points fixes à 156°15E, 1°30S (10 jours) et 156°10E, 1°45S (8 jours), interrompus par une journée d'intercomparaison de mesures météorologiques avec un navire océanographique australien... Ce rapport présente le déroulement de la campagne, le matériel et les méthodes employés et les premiers résultats obtenus. (D'aprÚs résumé d'auteur

    A dual sensor device to estimate fluid flow velocity at diffuse hydrothermal vents

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    Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 56 (2009): 2065-2074, doi:10.1016/j.dsr.2009.06.008.Numerous attempts have been made over the last thirty years to estimate fluid flow rates at hydrothermal vents, either at the exit of black smoker chimneys or within diffuse flow areas. In this study, we combine two methods to accurately estimate fluid flow velocities at diffuse flow areas. While the first method uses a hot film anemometer that performs high frequency measurements, the second allows a relatively rapid assessment of fluid flow velocity through video imagery and provides in situ data to calibrate the sensor. Measurements of flow velocities on hydrothermal diffuse flow areas were obtained on the Mid-Atlantic Ridge (MAR). They range from 1.1 to 4.9 mm/sec., at the substratum level, in low temperature (4.5 to 16.4°C) diffuse flow areas from the Tour Eiffel sulfide edifice. A strong correlation was observed between fluid flow velocities and temperature, supporting the possible use of temperature as a proxy to estimate flow rates in diffuse flow areas where such a simple linear flow/temperature relation is shown to dominate.The first part of this research was sponsored by a NOAA/NURP grant award #NA96RU0221 and NSF grant OCE-9901563 to MKT and JS. JS was also supported by a FCAR (Quebec) post-doctoral fellowship. The last part of the project was supported through the ANR DEEP OASES (ANR06 BDV005)

    STUDY OF THE MICROWAVE VACUUM DRYING PROCESS FOR A GRANULATED PRODUCT

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    The objectives of this work were to study and evaluate the process of drying a pharmaceutical granule from 21% to 3% (d.b.) moisture, also determining the power absorbed by the product, using a microwave assisted vacuum dryer with two absolute pressures: 50 and 75 mbar. A specific objective was to compare the drying kinetics of the microwave assisted vacuum process (MAVP) with two other drying processes, one using hot air convection and the other combining microwaves with hot air convection. The results of such a study showed that the drying kinetics were not affected by the vacuum levels, whereas the absorbed microwave power was higher for smaller vacuum levels. It was also observed that the samples obtained by the microwave assisted vacuum process, when submitted to compression, complied with the required specifications. The drying kinetics of the MAVP showed the shortest drying times when compared to the other drying processes.26231732

    Coupling the actuator line method to the high order meteorological les model Meso-NH to study wind farm wakes impacts on local meteorology

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    Offshore wind energy is now reaching the technological maturity, its capacity is increasing all over the world and this trend is projected to continue for several more years. Given this expectation, a better understanding of the relationship between the presence of wind farms and the atmospheric boundary layer is needed. Turbulent wakes produced by wind turbines can significantly impact the flow dynamics within wind farms and downstream of them. Operating offshore parks have already shown losses on energy production and effects on the local climate. In order to analyse the interactions occurring during these impacts, a new tool has been developed. This numerical tool is a coupling between the Actuator Line Method (ALM) and the open-source, non-hydrostatic mesoscale atmospheric model Meso-NH, based on the Large Eddy Simulation (LES) framework. The coupled Meso-NH + ALM system is first validated by using the experimental data obtained during the New MEXICO experiments. In particular, simulated and experimental loadings along the blades are compared. Then, a simulation of an idealized Horns Rev wind farm is performed using met mast measurements and reanalysis data for the “Horns Rev 1 photo case” as initial conditions. This new coupled system allows the exploration of the impact of wind farms on the lower levels of the atmosphere.Fil: Joulin, P. A.. French Institute of Petroleum Énergies nouvelles; Francia. Centre National de Recherches MĂ©tĂ©orologiques; FranciaFil: Mayol, MarĂ­a Laura. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Parque Centenario. Centro de SimulaciĂłn Computacional para Aplicaciones TecnolĂłgicas; ArgentinaFil: Blondel, F.. French Institute of Petroleum Énergies nouvelles; FranciaFil: Masson, Viviana Patricia. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; Argentina. Centre National de Recherches MĂ©tĂ©orologiques; FranciaFil: Rodier, Q.. Centre National de Recherches MĂ©tĂ©orologiques; FranciaFil: Lac, C.. Centre National de Recherches MĂ©tĂ©orologiques; Franci

    Three Corner Sat Constellation - New Mexico State University: Communications, LEO Telecommunications Services, Intersatellite Communications, and Ground Stations and Network

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    The Three Corner Satellite Constellation is part of the AFOSRlDARP A University Nanosatellite program. This project is a joint effort among Arizona State University (ASU), University of Colorado at Boulder (CU), and New Mexico State University (NMSU). The constellation will consist of three identical nanosatellites, that will demonstrate stereo imaging, innovative command and data handling, and formation flying with RF communications and a possibility of cellular phone communications through LEO telecommunications satellites. To achieve mission objectives, the satellites in the constellation and the ground communications network will need to be designed as a cooperative communications and control network that will allow the satellites in the constellation to form a virtual formation. In this paper, we will present the necessary communications and control architecture for the space segment and the ground segment to form this virtual formation that are NMSU\u27s responsibility in the program. Companion papers describe the respective areas of responsibility of the other partners: ASU -Project Management; Electrical Power System; Structures, Mechanisms, Thermal, and Radiation; Attitude/Orbit Determination and Control; Micropropulsion experiment; and ‱ Integration; CU -- Command & Data Handling, Distributed Operations, Stereoscopic Imaging, Science Operations, and Spacecraft Operations

    Swelling of Transported Smoke from Savanna Fires over the Southeast Atlantic Ocean

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    We use the recently released Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) Version 4.1 (V4) lidar data to study the smoke plumes transported from Southern African biomass burning areas. Significant improvements in the CALIPSO V4 Level 1 calibration and V4 Level 2 algorithms lead to a better representation of their optical properties, with the aerosol subtype improvements being particularly relevant to smoke over this area. For the first time, we show evidence of smoke particles increasing in size, evidenced in their particulate color ratios, as they are transported over the South Atlantic Ocean from the source regions over Southern Africa. We hypothesize that this is due to hygroscopic swelling of the smoke particles and is reflected in the higher relative humidity in the middle troposphere for profiles with smoke. This finding may have implications for radiative forcing estimates over this area and is also relevant to the ORACLES field mission

    Hair Manganese and Hyperactive Behaviors: Pilot Study of School-Age Children Exposed through Tap Water

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    BACKGROUND: Neurotoxic effects are known to occur with inhalation of manganese particulates, but very few data are available on exposure to Mn in water. We undertook a pilot study in a community in QuĂ©bec (Canada) where naturally occurring high Mn levels were present in the public water system. Our objective was to test the hypothesis that greater exposure to Mn via drinking water would be reflected in higher Mn content in hair which, in turn, would be associated with increased level of hyperactive behaviors. METHODS: Forty-six children participated in the study, 24 boys and 22 girls, 6–15 years of age (median, 11 years). Their homes received water from one of two wells (W) with different Mn concentrations: W1: mean 610 ÎŒg/L; W2: mean 160 ÎŒg/L. The Revised Conners’ Rating Scale for parents (CPRS-R) and for teachers (CTRS-R) were administered, providing T-scores on the following subscales: Oppositional, Hyperactivity, Cognitive Problems/Inattention, and ADHD Index. RESULTS: Children whose houses were supplied by W1 had higher hair Mn (MnH) than those supplied by W2 (mean 6.2 ± 4.7 ÎŒg/g vs. 3.3 ± 3.0 ÎŒg/g, p = 0.025). MnH was significantly associated with T-scores on the CTRS-R Oppositional (p = 0.020) and Hyperactivity (p = 0.002) subscales, after adjustment for age, sex, and income. All children with Oppositional and Hyperactivity T-scores ≄ 65 had MnH > 3.0 ÎŒg/g. CONCLUSIONS: The findings of this pilot study are sufficiently compelling to warrant more extensive investigations into the risks of Mn exposure in drinking water

    Swelling of Transported Smoke from Savanna fires over the Southeast Atlantic Ocean

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    We use the recently released Version 4 (V4) lidar data products from CALIPSO to study the smoke plumes transported from Southern African biomass burning areas. The significant improvements in CALIPSO V4 Level 1 calibration and the V4 Level 2 aerosol subtyping algorithms, the latter being particularly relevant to biomass burning smoke over this area, lead to a better representation of their optical properties. For the first time, we show evidence of smoke particles increasing in size, evidenced in their particulate color ratios, as they are transported over the South Atlantic Ocean from the source regions over Southern Africa. This is likely due to hygroscopic swelling of the smoke particles and is reflected in the higher relative humidity in the middle troposphere for profiles with smoke. This finding may have implications for radiative forcing estimates over this area and is relevant to the ORACLES field mission that is currently underway
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