245 research outputs found

    A COMPARISON OF UNDERWATER GLIDING AND KICKING TECHNIQUES

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    Net forces created when towing swimmers through water were examined for gliding and undelwater kicking. Sixteen experienced male swimmers of similar body shape were towed through water via a motorised winch and pulley system. A load cell measured net force (propulsive force - drag force) at velocities of 1.6, 1.9, 2.2, 2.5 and 3.1 ms-', respectively. At each velocity swimmers performed a prone streamline glide; lateral streamline glide; prone freestyle kick; prone dolphin kick; and lateral dolphin kick. A 2- way repeated measures ANOVA revealed significant differences between the gliding and kicking conditions at different velocities. Results suggest that there is an optimal velocity at which to begin undelwater kicking in order to prevent energy loss from excessive active drag

    The Molecular Identification of Organic Compounds in the Atmosphere: State of the Art and Challenges

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    Valorisation of Biowastes for the Production of Green Materials Using Chemical Methods

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    With crude oil reserves dwindling, the hunt for a sustainable alternative feedstock for fuels and materials for our society continues to expand. The biorefinery concept has enjoyed both a surge in popularity and also vocal opposition to the idea of diverting food-grade land and crops for this purpose. The idea of using the inevitable wastes arising from biomass processing, particularly farming and food production, is, therefore, gaining more attention as the feedstock for the biorefinery. For the three main components of biomass—carbohydrates, lipids, and proteins—there are long-established processes for using some of these by-products. However, the recent advances in chemical technologies are expanding both the feedstocks available for processing and the products that be obtained. Herein, this review presents some of the more recent developments in processing these molecules for green materials, as well as case studies that bring these technologies and materials together into final products for applied usage
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