The Experts below are selected from a list of 375 Experts worldwide ranked by ideXlab platform
Zhenhua Huang - One of the best experts on this subject based on the ideXlab platform.
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an experimental study of a floating breakwater with asymmetric pneumatic chambers for wave energy extraction
Applied Energy, 2013Co-Authors: Fang He, Zhenhua HuangAbstract:Integrating oscillating-water-column type converters (pneumatic chambers) with slack-moored floating breakwaters can be a viable option for cost-sharing between wave energy capturing devices and shore-protection structures, and thus enhance the cost-effectiveness of wave energy utilization. When designing such integrated systems, it is desirable to have a system that can capture wave energy over a wide range of wave frequency. In this study, a configuration of floating breakwater with asymmetric pneumatic chambers (a narrower chamber on the seaside and a wider chamber on the leeside) is proposed to increase the amplitude of the oscillating air-pressures inside both chambers over a wide range of wave frequency (thus to improve the performance in wave energy extraction). A series of experiments were carried out under regular wave conditions to study the effects of asymmetric pneumatic chambers on the hydrodynamic performance of the floating breakwater and on the oscillating air-pressures inside the two chambers. It was shown that (1) the breakwater with asymmetric chambers performed as good as that with symmetric chambers in terms of wave transmission and motion responses and (2) with asymmetric configuration, it is possible to increase the amplitude of the oscillating air-pressures inside both chambers. The new concept provides a promising way to extend the frequency range over which wave energy can be extracted.
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hydrodynamic performance of a rectangular floating breakwater with and without pneumatic chambers an experimental study
Ocean Engineering, 2012Co-Authors: Fang He, Zhenhua HuangAbstract:Abstract In this study, we investigated experimentally the hydrodynamic performance of floating breakwaters with and without pneumatic chambers. The experimental results showed that the pneumatic chambers significantly enhanced the wave energy dissipation as well as reduced the wave transmission. With the installation of the pneumatic chambers, the water inside the chambers helped to reduce the surge response, while the chamber walls increased the moment of inertia of the breakwater and thus mitigated the pitch response. The air pressure fluctuations inside the pneumatic chambers and the effects of draught were also examined in the experiments. The overall results illustrate that the new design of floating breakwater is more effective for wave protection, and also holds the potential for simultaneous wave energy conversion into electricity by installing Wells turbines to the pneumatic chambers.
Fang He - One of the best experts on this subject based on the ideXlab platform.
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an experimental study of a floating breakwater with asymmetric pneumatic chambers for wave energy extraction
Applied Energy, 2013Co-Authors: Fang He, Zhenhua HuangAbstract:Integrating oscillating-water-column type converters (pneumatic chambers) with slack-moored floating breakwaters can be a viable option for cost-sharing between wave energy capturing devices and shore-protection structures, and thus enhance the cost-effectiveness of wave energy utilization. When designing such integrated systems, it is desirable to have a system that can capture wave energy over a wide range of wave frequency. In this study, a configuration of floating breakwater with asymmetric pneumatic chambers (a narrower chamber on the seaside and a wider chamber on the leeside) is proposed to increase the amplitude of the oscillating air-pressures inside both chambers over a wide range of wave frequency (thus to improve the performance in wave energy extraction). A series of experiments were carried out under regular wave conditions to study the effects of asymmetric pneumatic chambers on the hydrodynamic performance of the floating breakwater and on the oscillating air-pressures inside the two chambers. It was shown that (1) the breakwater with asymmetric chambers performed as good as that with symmetric chambers in terms of wave transmission and motion responses and (2) with asymmetric configuration, it is possible to increase the amplitude of the oscillating air-pressures inside both chambers. The new concept provides a promising way to extend the frequency range over which wave energy can be extracted.
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hydrodynamic performance of a rectangular floating breakwater with and without pneumatic chambers an experimental study
Ocean Engineering, 2012Co-Authors: Fang He, Zhenhua HuangAbstract:Abstract In this study, we investigated experimentally the hydrodynamic performance of floating breakwaters with and without pneumatic chambers. The experimental results showed that the pneumatic chambers significantly enhanced the wave energy dissipation as well as reduced the wave transmission. With the installation of the pneumatic chambers, the water inside the chambers helped to reduce the surge response, while the chamber walls increased the moment of inertia of the breakwater and thus mitigated the pitch response. The air pressure fluctuations inside the pneumatic chambers and the effects of draught were also examined in the experiments. The overall results illustrate that the new design of floating breakwater is more effective for wave protection, and also holds the potential for simultaneous wave energy conversion into electricity by installing Wells turbines to the pneumatic chambers.
Marc O Eberhard - One of the best experts on this subject based on the ideXlab platform.
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effects of temperature variations on precast prestressed concrete bridge girders
Journal of Bridge Engineering, 2005Co-Authors: Paul J. Barr, John F Stanton, Marc O EberhardAbstract:The monitoring of a precast, prestressed girder bridge during fabrication and service provided the opportunity to observe temperature variations and to evaluate the accuracy of calculated strains and Cambers. The use of high curing temperatures during fabrication affects the level of prestress because the strand length is fixed during the heating, the coefficients of thermal expansion of steel and concrete differ, and the concrete temperature distribution may not be uniform. For the girders discussed here, these effects combined to reduce the calculated prestressing stress from the original design values at release by 3 to 7%, to reduce the initial camber by 26 to 40%, and to increase the bottom tension stress in service by 12 to 27%. The main effect of applying the standard service temperature profiles to the bridge was to increase the bottom stress by 60% of the allowable tension stress. These effects can be compensated for by increasing the amount of prestressing steel, but in highly stressed girders, such an increase leads to increased prestress losses ~requiring yet more strands! and higher concrete strength requirements at release.
Bernhard M Degnan - One of the best experts on this subject based on the ideXlab platform.
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The ontogeny of choanocyte chambers during metamorphosis in the demosponge Amphimedon queenslandica
EvoDevo, 2016Co-Authors: Shunsuke Sogabe, Nagayasu Nakanishi, Bernhard M DegnanAbstract:Background The aquiferous body plan of poriferans revolves around internal chambers comprised of choanocytes, a cell type structurally similar to choanoflagellates. These choanocyte chambers perform a range of physiological and developmental functions, including the capture of food and the generation of stem cells. Despite the increasing interest for choanocytes as sponge stem cells, there is limited knowledge on the development of choanocyte chambers. Using a combination of cell lineage tracing, antibody staining and EdU labeling, here we examine the development of choanocytes and the chambers they comprise during metamorphosis in the marine demosponge Amphimedon queenslandica . Results Lineage-tracing experiments show that larval epithelial cells transform into mesenchymal pluripotent stem cells, resembling archeocytes, within 24 h of initiating metamorphosis. By 36 h, some of these labeled archeocyte-like cells have differentiated into choanocytes that will form the first postlarval choanocyte chambers. Non-labeled cells also contribute to these primary choanocyte chambers, consistent with these chambers being a chimera of multiple transdifferentiated larval cell types and not the proliferation of a single choanocyte precursor. Moreover, cell proliferation assays demonstrate that, following the initial formation of choanocyte chambers, chambers grow at least partially by the proliferation of choanocytes within the chamber, although recruitment of individual cells into established chambers also appears to occur. EdU labeling of postlarvae and juveniles reveals that choanocyte chambers are the primary location of cell proliferation during metamorphosis. Conclusion Our results show that multiple larval cell lineages typically contribute to formation of individual choanocyte chambers at metamorphosis, contrary to previous reports in other species that show sponge choanocyte chambers form clonally. Choanocytes in postlarval and juvenile A. queenslandica chambers can also divide, with choanocyte chambers being the primary location of cell proliferation. Interestingly, the level of cell proliferation varies greatly between chambers and appears to be contingent on the size, location and developmental state of the chamber. Small chambers on the periphery of the body tend to possess more dividing cells. As choanocytes can also dedifferentiate into archeocyte-like cells, cell proliferation in chambers may not only contribute to chamber growth and self-renewal but also increase the number of pluripotent archeocytes.
Wei Haoyang - One of the best experts on this subject based on the ideXlab platform.
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study of different construction processes affecting the installation of appropriate Cambers for long span railway cable stayed bridges
Mathematical Models and Methods in Applied Sciences, 2013Co-Authors: Chen Zengshun, Zhang Cheng, Huang Guanrong, Wei HaoyangAbstract:There are few studies on the installation of appropriate Cambers for long-span railway cable-stayed bridges at home and abroad. This article describes the influential factors of thte installation of Cambers, and analyses its theories and approaches, as well as takes use of design formula for appropriate camber installation. Combining project cases of long-span railway cable-stayed bridges, and exploiting FEM software-Midas civil2010, the article has an analytic study on effects of different construction processes on camber installation, which is the basis of installing Cambers of such bridges in the future.
