Advanced search in Research products
Research products
arrow_drop_down
Searching FieldsTerms
Any field
arrow_drop_down
includes
arrow_drop_down
The following results are related to NEANIAS Atmospheric Research Community. Are you interested to view more results? Visit OpenAIRE - Explore.

  • NEANIAS Atmospheric Research Community
  • Open Access
  • Publications
  • Research data
  • FR
  • Portuguese
  • Hal-Diderot

Date (most recent)
arrow_drop_down
  • image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Authors: Zocatelli, R.; Bernades, M.; Turcq, Bruno; Campello Cordeiro, r.; +4 Authors

    International audience; Este estudo teve como objetivo avaliar a composição da matéria orgânica (MO) através de análises elementares, isotópicas e moleculares em dois testemunhos coletados na Lagoa do Caçó que registram os últimos 20.000 cal yrs BP e testar o potencial de ferramentas da geoquímica molecular no estudo paleoambiental. A Lagoa do Caçó é localizada no Maranhão numa área influenciada pelo deslocamento sazonal da zona de convergência intertropical (ZCIT). Os resultados e interpretações obtidos a partir da geoquímica orgânica durante o tardi-glacial evidenciaram a importância da abordagem multiparamétrica e corroboram os trabalhos prévios validando o uso dos fenóis da lignina e dos pigmentos sedimentares como ferramentas na interpretação paleoambiental em zona tropical. Foi possível identifcar três diferentes Fases holocênicas jamais mostradas em trabalhos precedentes destacando o potencial destes biomarcadores.

    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/ Horizon / Pleins tex...arrow_drop_down
    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Horizon / Pleins textes
    Other literature type . 2012
    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Geochimica Brasiliensis
    Article . 2013
    Data sources: DOAJ-Articles
    DOAJ
    Article . 2013
    Data sources: DOAJ
    0
    citations0
    popularityAverage
    influenceAverage
    impulseAverage
    BIP!Powered by BIP!
    more_vert
  • image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Authors: Mendes, Marianna;

    Geosynthetic Clay Liners (GCLs) are synthetic materials composed by a core of calcium or sodium bentonite, either in powder or granular, bonded to one or more geosynthetic layers (geotextile or geomembrane, in general). These layers are usually bonded by an adhesive, needle-punching, stitch-bonding or sewing. When hydrated and confined, they fulfil functions of liquid or gas barrier with their hydraulic performance depending in most cases on the hydraulic conductivity of the bentonite. Thanks to their low permeability to water and gases, GCLs are often used in municipal solid waste landfill applications, combined to compacted clay liners (CCL) or with geomembranes (GM) as part of both bottom and cover liners. Previous studies were conducted to investigate the most important factors that influence the gas/liquid flow rate through GCLs or composite liners. Although the nature of bentonite is so important in the permeability of the GCLs there is a lack of data in the literature regarding the influence of the nature of the bentonite on the gas flow through GCLs and liquid flow through composite liners involving GCLs. That is what this thesis aims at clarifying. Furthermore, in conjunction with the nature of the bentonite, the impact of the manufacturing process of the GCL on the flow rate and transmissivity at GM-GCL interfaces was also discussed. Two studies were performed: (i) investigation of the GCL permeability to gas simulating the covering conditions of municipal solid waste landfill; (ii) investigation of liquid transfer through composite liners GM-GCL-CCL due to a defect in the geomembrane, simulating typical conditions of bottom liners in landfills. In the first study, an apparatus recently proposed, based on the falling pressure method, was used in tests to verify the GCL permeability to gas. Three stitch bonded GCLs from the same manufacturer differing by the bentonite nature (natural sodium, natural calcium and activated calcium) were tested. The results showed that the gravimetric water content of the GCL necessary to attain a certain permeability value depends on the bentonite nature, which was not observed in terms of volumetric water content. However, other factors showed to be more important than the nature of bentonite in the GCL permeability to gas: the desiccation due to the gas flow can increase significantly the permeability, which compromise the GCL performance as a gas barrier. The second study focused in investigating the influence of the GCL characteristics in the liquid flow through a composite liner under bottom liners solicitations. Four types of GCLs with two different bonding processes (stitch-bonded or needle-punched) and different bentonites (natural sodium or natural calcium) were tested. The results obtained showed no significant differences among flow rate versus time in most of the tests performed, especially after steady-state conditions of flow having been reached. An analytical solution was employed to estimate the transmissivity of the GM-GCL interfaces. This solution also allowed predictions of flow rates and radius of wetted areas for typical configurations of composite liners in the field. The results obtained showed little influence of the nature of the bentonite and the predominance of influence of the presence of preferential flow paths between the geomembrane and the GCL surface on the transmissivity of GM-GCL interfaces and flow rates through composite liners. Géosynthétiques bentonitiques (GCLs) sont matériaux synthétiques composées par un noyau de bentonite sodique ou calcique, en poudre ou en granulats, liés à un ou plus couches de géosynthétiques (geotextiles ou geomembranes en générale). Les GCLs peuvent être aiguillettes, cousus, liés par adhésive, entre autres. Lorsque le GCL est confinée et hydratée, il présente de bonnes propriétés d'étanchéité pour accomplir la fonction de barrière. Sa performance dépend, généralement de la conductivité hydraulique de la bentonite. Grâce à leur faible perméabilité, les GCLs sont souvent installés au fond ou couverture des Installations de Stockage de déchets (ISD) associés avec l'argile compactée (CCL) ou avec la geomembrane (GM). Des études précédentes ont investigué les facteurs qui affectent la fuite de gaz/liquide au travers les GCLs ou les étanchéités composites. Malgré la nature de la bentonite soit si importante pour la perméabilité des GCLs, il n'y a pas dans la littérature concernant l'influence de la nature de la bentonite dans la fuite de gaz au travers les GCL ou la fuite de liquide au travers les étanchéités composites. C'est pour quoi cette étude s'intéresse. On propose d'étudier également l'effet du procès de manufacture du GCL dans l'écoulement de liquide et transmissivité de l'interface GM-GCL. Deux études sont été menés : (i) investigation de la perméabilité aux gaz des GCL ; (ii) investigation du transfert de liquide au travers des étanchéités composites GM-GCL-CCL du a un endommagement dans la GM. Pour la première étude un équipement proposé récemment, basée sur la méthode de chute de pression a été utilisé pour mesurer la perméabilité aux gaz des GCLs. Trois GCLs cousus à base de bentonites de différentes natures (sodique naturelle, calcique naturelle et calcique activée) ont été testés. Les résultats indiquent que la teneur en eau gravimétrique nécessaire pour atteindre une certaine valeur de perméabilité dépend de la bentonite. Concernant la teneur en eau volumique, pratiquement la même relation a été obtenue, indépendamment de la bentonite. D'autres facteurs ont affecté plus significativement la perméabilité au gaz des GCLs : la dessiccation du au flux de gaz peut causer l'augmentation de la perméabilité et compromettre la performance du GCL comme barrière étanche. La deuxième étude s'est concentré dans l'investigation de l'influence des caractéristiques du GCL sur l'écoulement de liquide au travers une étanchéité composite.GM-GCL-CCL. Quatre types de GCLs avec deux procès de manufacture (aiguilleté ou cousu) et deux natures de bentonite (sodique naturelle ou calcique naturelle) ont été testés. Les résultats indiquent que la nature de la bentonite n'affecte le flux que pendant le régime transitoire. Les valeurs de transmissivité de l'interface GM-GCL ont été calculées par une solution analytique qui a également possibilité des prédictions du débit de fuite au travers des étanchéités composites en configurations typiques du fond des ISD. Les résultats indiquent une faible influence de la nature de la bentonite dans l'écoulement de liquide au travers les étanchéités composites. Au même temps on a note une certaine influence des chemins préférentielles de flux, notamment pendant le régime transitoire.

    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/ Hyper Article en Lig...arrow_drop_down
    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    0
    citations0
    popularityAverage
    influenceAverage
    impulseAverage
    BIP!Powered by BIP!
    more_vert
Powered by OpenAIRE graph
Advanced search in Research products
Research products
arrow_drop_down
Searching FieldsTerms
Any field
arrow_drop_down
includes
arrow_drop_down
The following results are related to NEANIAS Atmospheric Research Community. Are you interested to view more results? Visit OpenAIRE - Explore.
  • image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Authors: Zocatelli, R.; Bernades, M.; Turcq, Bruno; Campello Cordeiro, r.; +4 Authors

    International audience; Este estudo teve como objetivo avaliar a composição da matéria orgânica (MO) através de análises elementares, isotópicas e moleculares em dois testemunhos coletados na Lagoa do Caçó que registram os últimos 20.000 cal yrs BP e testar o potencial de ferramentas da geoquímica molecular no estudo paleoambiental. A Lagoa do Caçó é localizada no Maranhão numa área influenciada pelo deslocamento sazonal da zona de convergência intertropical (ZCIT). Os resultados e interpretações obtidos a partir da geoquímica orgânica durante o tardi-glacial evidenciaram a importância da abordagem multiparamétrica e corroboram os trabalhos prévios validando o uso dos fenóis da lignina e dos pigmentos sedimentares como ferramentas na interpretação paleoambiental em zona tropical. Foi possível identifcar três diferentes Fases holocênicas jamais mostradas em trabalhos precedentes destacando o potencial destes biomarcadores.

    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/ Horizon / Pleins tex...arrow_drop_down
    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Horizon / Pleins textes
    Other literature type . 2012
    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Geochimica Brasiliensis
    Article . 2013
    Data sources: DOAJ-Articles
    DOAJ
    Article . 2013
    Data sources: DOAJ
    0
    citations0
    popularityAverage
    influenceAverage
    impulseAverage
    BIP!Powered by BIP!
    more_vert
  • image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    Authors: Mendes, Marianna;

    Geosynthetic Clay Liners (GCLs) are synthetic materials composed by a core of calcium or sodium bentonite, either in powder or granular, bonded to one or more geosynthetic layers (geotextile or geomembrane, in general). These layers are usually bonded by an adhesive, needle-punching, stitch-bonding or sewing. When hydrated and confined, they fulfil functions of liquid or gas barrier with their hydraulic performance depending in most cases on the hydraulic conductivity of the bentonite. Thanks to their low permeability to water and gases, GCLs are often used in municipal solid waste landfill applications, combined to compacted clay liners (CCL) or with geomembranes (GM) as part of both bottom and cover liners. Previous studies were conducted to investigate the most important factors that influence the gas/liquid flow rate through GCLs or composite liners. Although the nature of bentonite is so important in the permeability of the GCLs there is a lack of data in the literature regarding the influence of the nature of the bentonite on the gas flow through GCLs and liquid flow through composite liners involving GCLs. That is what this thesis aims at clarifying. Furthermore, in conjunction with the nature of the bentonite, the impact of the manufacturing process of the GCL on the flow rate and transmissivity at GM-GCL interfaces was also discussed. Two studies were performed: (i) investigation of the GCL permeability to gas simulating the covering conditions of municipal solid waste landfill; (ii) investigation of liquid transfer through composite liners GM-GCL-CCL due to a defect in the geomembrane, simulating typical conditions of bottom liners in landfills. In the first study, an apparatus recently proposed, based on the falling pressure method, was used in tests to verify the GCL permeability to gas. Three stitch bonded GCLs from the same manufacturer differing by the bentonite nature (natural sodium, natural calcium and activated calcium) were tested. The results showed that the gravimetric water content of the GCL necessary to attain a certain permeability value depends on the bentonite nature, which was not observed in terms of volumetric water content. However, other factors showed to be more important than the nature of bentonite in the GCL permeability to gas: the desiccation due to the gas flow can increase significantly the permeability, which compromise the GCL performance as a gas barrier. The second study focused in investigating the influence of the GCL characteristics in the liquid flow through a composite liner under bottom liners solicitations. Four types of GCLs with two different bonding processes (stitch-bonded or needle-punched) and different bentonites (natural sodium or natural calcium) were tested. The results obtained showed no significant differences among flow rate versus time in most of the tests performed, especially after steady-state conditions of flow having been reached. An analytical solution was employed to estimate the transmissivity of the GM-GCL interfaces. This solution also allowed predictions of flow rates and radius of wetted areas for typical configurations of composite liners in the field. The results obtained showed little influence of the nature of the bentonite and the predominance of influence of the presence of preferential flow paths between the geomembrane and the GCL surface on the transmissivity of GM-GCL interfaces and flow rates through composite liners. Géosynthétiques bentonitiques (GCLs) sont matériaux synthétiques composées par un noyau de bentonite sodique ou calcique, en poudre ou en granulats, liés à un ou plus couches de géosynthétiques (geotextiles ou geomembranes en générale). Les GCLs peuvent être aiguillettes, cousus, liés par adhésive, entre autres. Lorsque le GCL est confinée et hydratée, il présente de bonnes propriétés d'étanchéité pour accomplir la fonction de barrière. Sa performance dépend, généralement de la conductivité hydraulique de la bentonite. Grâce à leur faible perméabilité, les GCLs sont souvent installés au fond ou couverture des Installations de Stockage de déchets (ISD) associés avec l'argile compactée (CCL) ou avec la geomembrane (GM). Des études précédentes ont investigué les facteurs qui affectent la fuite de gaz/liquide au travers les GCLs ou les étanchéités composites. Malgré la nature de la bentonite soit si importante pour la perméabilité des GCLs, il n'y a pas dans la littérature concernant l'influence de la nature de la bentonite dans la fuite de gaz au travers les GCL ou la fuite de liquide au travers les étanchéités composites. C'est pour quoi cette étude s'intéresse. On propose d'étudier également l'effet du procès de manufacture du GCL dans l'écoulement de liquide et transmissivité de l'interface GM-GCL. Deux études sont été menés : (i) investigation de la perméabilité aux gaz des GCL ; (ii) investigation du transfert de liquide au travers des étanchéités composites GM-GCL-CCL du a un endommagement dans la GM. Pour la première étude un équipement proposé récemment, basée sur la méthode de chute de pression a été utilisé pour mesurer la perméabilité aux gaz des GCLs. Trois GCLs cousus à base de bentonites de différentes natures (sodique naturelle, calcique naturelle et calcique activée) ont été testés. Les résultats indiquent que la teneur en eau gravimétrique nécessaire pour atteindre une certaine valeur de perméabilité dépend de la bentonite. Concernant la teneur en eau volumique, pratiquement la même relation a été obtenue, indépendamment de la bentonite. D'autres facteurs ont affecté plus significativement la perméabilité au gaz des GCLs : la dessiccation du au flux de gaz peut causer l'augmentation de la perméabilité et compromettre la performance du GCL comme barrière étanche. La deuxième étude s'est concentré dans l'investigation de l'influence des caractéristiques du GCL sur l'écoulement de liquide au travers une étanchéité composite.GM-GCL-CCL. Quatre types de GCLs avec deux procès de manufacture (aiguilleté ou cousu) et deux natures de bentonite (sodique naturelle ou calcique naturelle) ont été testés. Les résultats indiquent que la nature de la bentonite n'affecte le flux que pendant le régime transitoire. Les valeurs de transmissivité de l'interface GM-GCL ont été calculées par une solution analytique qui a également possibilité des prédictions du débit de fuite au travers des étanchéités composites en configurations typiques du fond des ISD. Les résultats indiquent une faible influence de la nature de la bentonite dans l'écoulement de liquide au travers les étanchéités composites. Au même temps on a note une certaine influence des chemins préférentielles de flux, notamment pendant le régime transitoire.

    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/ Hyper Article en Lig...arrow_drop_down
    image/svg+xml art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos Open Access logo, converted into svg, designed by PLoS. This version with transparent background. http://commons.wikimedia.org/wiki/File:Open_Access_logo_PLoS_white.svg art designer at PLoS, modified by Wikipedia users Nina, Beao, JakobVoss, and AnonMoos http://www.plos.org/
    0
    citations0
    popularityAverage
    influenceAverage
    impulseAverage
    BIP!Powered by BIP!
    more_vert
Powered by OpenAIRE graph