64 research outputs found

    Dynamics of nanoscale droplets on moving surfaces

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    We use molecular dynamics (MD) simulations to investigate the dynamic wetting of nanoscale water droplets on moving surfaces. The density and hydrogen bonding profiles along the direction normal to the surface are reported, and the width of the water depletion layer is evaluated first for droplets on three different static surfaces: silicon, graphite, and a fictitious superhydrophobic surface. The advancing and receding contact angles, and contact angle hysteresis, are then measured as a function of capillary number on smooth moving silicon and graphite surfaces. Our results for the silicon surface show that molecular displacements at the contact line are influenced greatly by interactions with the solid surface and partly by viscous dissipation effects induced through the movement of the surface. For the graphite surface, however, both the advancing and receding contact angles values are close to the static contact angle value and are independent of the capillary number; i.e., viscous dissipation effects are negligible. This finding is in contrast with the wetting dynamics of macroscale water droplets, which show significant dependence on the capillary number

    On Vastness and Variability: Cultural Transmission, Historicity, and the Paleoindian Record in Eastern South America

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    Arqueologia e história indígena no Pantanal

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    O artigo apresenta uma síntese dos dados arqueológicos sobre o Pantanal e o seu entorno, principalmente em Mato Grosso e Mato Grosso do Sul. Elaborado com base na noção de arqueologia como história indígena de longa duração, o artigo considera as trajetórias de estabelecimento e consolidação territorial da ocupação indígena regional, os processos de formação da configuração etnográfica encontrada pelos europeus e os impactos do colonialismo. O principal objetivo consiste em mostrar que a diversidade cultural característica do cenário etnográfico pantaneiro está associada à dinâmica histórica e cultural da ocupação indígena desde períodos anteriores à chegada dos conquistadores e colonizadores de origem europeia.The article presents an overview of the archaeological data on the Pantanal and its surrounding areas, mainly in Mato Grosso and Mato Grosso do Sul. Prepared based on the notion of archeology as long term indigenous history, the article considers the trajectories of territorial establishment and consolidation of the regional indigenous occupation, the formation processes of ethnographic setting found by Europeans and the impact of colonialism. The main objective is to show that cultural diversity characteristic of the Pantanal ethnographic scenario is associated with historical and cultural dynamics of indigenous occupation from periods prior to the arrival of the conquistadors and settlers of European origin

    New Chemical Family of [ n

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    EPTC Effects on Sicklepod Petiolar Fatty Acids

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