142 research outputs found

    Coastal sedimentation

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    Several important coastal sedimentation problems are identified. Application of existing or anticipated remote sensing techniques to examine these problems is considered. Specifically, coastal fine particle sediment systems, floods and hy hurricanes and sedimentation f of coastal systems, routes and rates of sediment transport on continental shelves, and dredging and dredged material disposal are discussed

    Wind turbine blade design

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    A detailed review of the current state-of-art for wind turbine blade design is presented, including theoretical maximum efficiency, propulsion, practical efficiency, HAWT blade design, and blade loads. The review provides a complete picture of wind turbine blade design and shows the dominance of modern turbines almost exclusive use of horizontal axis rotors. The aerodynamic design principles for a modern wind turbine blade are detailed, including blade plan shape/quantity, aerofoil selection and optimal attack angles. A detailed review of design loads on wind turbine blades is offered, describing aerodynamic, gravitational, centrifugal, gyroscopic and operational conditions

    A device for collecting in-situ samples of suspended sediment for microscopic analysis

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    An in-situ sampler for collecting small samples of suspended sediment for microscopic analysis bas been built and tested. The device rapidly freezes a thin layer of water entrapping all of the suspended particles in it; when the sampler is recovered, the disc of ice is placed on a suitable substrate and freeze-dried. The particles can then be examined in an undisturbed state with a light microscope or with an electron microscope

    Transverse permeability of dry fiber preforms manufactured by automated fiber placement

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    This work presents a correlation between the transverse permeability of a preform and the process variability of the automated dry fiber placement manufacturing technique. In this study, an experimental and numerical analysis of the dry tape preform, with a focus on its through-thickness permeability, has been undertaken. Geometric models, containing flow channels of two different width dry tape carbon preforms, have been created in the TexGen modeller. A Computational fluid dynamics (CFD) simulation has been undertaken to obtain the predicted through-thickness-permeability of the dry tape preform. A parametric study on the effect of different dry tape gap sizes on the permeability of the preform is presented. An in-situ compaction study, carried out in an X-CT machine, revealed that the gap sizes were irregular throughout the manufactured preforms. In addition, an experimental investigation of the through-thickness permeability, which is based on a saturated flow condition at a thickness corresponding to full vacuum pressure, is also presented. The permeability prediction based on the X-CT re-constructed geometric model has been validated using the experimental data. A further parametric study has revealed that the process variablity in automated dry fibre placement influences the through-thickness permeability by a factor of upto 5

    Wind turbine blade design review

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    A detailed review of the current state-of-art for wind turbine blade design is presented, including theoretical maximum efficiency, propulsion, practical efficiency, HAWT blade design, and blade loads. The review provides a complete picture of wind turbine blade design and shows the dominance of modern turbines almost exclusive use of horizontal axis rotors. The aerodynamic design principles for a modern wind turbine blade are detailed, including blade plan shape/quantity, aerofoil selection and optimal attack angles. A detailed review of design loads on wind turbine blades is offered, describing aerodynamic, gravitational, centrifugal, gyroscopic and operational conditions

    On Selecting the excess temperature to minimize the entrainment mortality rate

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    In selecting an excess temperature at which to operate a power plant cooling system it has been customary to consider only thermal stresses and to use the ratio of the number of organisms killed to the number of organisms entrained. This frequently leads to the selection of a low excess temperature, AT, which, in turn, requires a large volume flow of cooling water. When mortalities due to physical and chemical stresses are included and the total number of entrained organisms killed is taken as the measure of the environmental damage, it becomes evident that the choice of a low excess temperature is seldom, if ever, best
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