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Wang B.,Hohai University | Wang B.,Chongqing Three Gorges University | Zhou H.,Hohai University | Zhou H.,China Energy Engineering Group Co. | Jiao Y.,Hohai University
Shuili Fadian Xuebao/Journal of Hydroelectric Engineering | Year: 2014

Supply chain, quality supervision decision and quality guarantee deposit detaining strategy of the owner and contractor are studied for hydraulic project construction in different conditions of information. A quality gain model has been developed with two owner's decision variables of quality supervision level and quality guarantee deposit detaining, and one contractor's decision variable of quality control level; optimal solutions have been derived for the owner's variables under asymmetric information by the maximum principle. Through simulation and calculation, the relationships between the three variables in different conditions of information are analyzed. This method is useful for improvement on the effectiveness and reliability of the owner's quality supervision and achievement of desired quality control objectives and quality gains. © Copyright. Source

Yi S.,China Energy Engineering Group Co. | Yi S.,University of La Coruna | Samper J.,University of La Coruna | Naves A.,University of La Coruna | Soler J.M.,CSIC - Institute of Environmental Assessment And Water Research
Environmental Earth Sciences | Year: 2015

In situ diffusion experiments are performed in underground research laboratories for understanding and quantifying radionuclide diffusion from underground radioactive waste repositories. The in situ diffusion and retention, DR, experiment was performed at the Mont Terri underground research laboratory, Switzerland, to characterize the diffusion and retention parameters of the Opalinus clay. Several tracers were injected instantaneously in the circulating artificial water and were then allowed to diffuse into the clay rock through two porous packed-off sections of a borehole drilled normal to the bedding of the clay formation. This paper presents a single-site multicomponent reactive transport model of Cs+, a tracer used in the DR experiment which sorbs onto Opalinus clay via cation exchange. The reactive transport model accounts for the diffusive-reactive transport of 11 primary species and 22 aqueous complexes, and the water–rock interactions for 5 cation exchange and 3 mineral dissolution/precipitation reactions. Most of the solutes except for Cs+ diffuse from the Opalinus clay formation into the injection interval because the concentrations in the initial Opalinus clay pore water are larger than those of the initial water in the circulation system. Calcite dissolves near the borehole while dolomite precipitates. Dissolved Cs+ sorbs by exchanging with Ca2+ in the exchange complex. The computed dilution curve of Cs+ in the circulating fluid is most sensitive to the effective diffusion, De, of the filter, the selectivity coefficient of Na+ to Cs+, KNa–Cs and De of the borehole disturbed zone. The apparent distribution coefficient of Cs+, Kad, in the formation varies in space and time from 100 to 165 L/kg due to the temporal changes in the water chemistry in the formation. The results of a sensitivity run in which the initial chemical composition of the Opalinus pore water is the same as the initial chemical composition of the water in the circulation system show that the changes in Kad are negligible. The dilution curve of Cs+ computed with the reactive transport model coincides with that obtained with the Kd model. The tracer concentrations along the overcoring profiles computed with the Kd model, however, differ significantly from those computed with the reactive transport model. Therefore, a reactive transport model is needed for the appropriate interpretation of the Cs+ overcoring data from the DR diffusion experiment. © 2015, Springer-Verlag Berlin Heidelberg. Source

Wang W.,Jiangsu University | Wang Y.,Jiangsu University | Liu R.,China Energy Engineering Group Co. | Li Y.,Lanzhou University of Technology | And 2 more authors.
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2014

The paper aims to deal with the numerical simulation of cavitation phenomena inside the centrifugal pump and analyze the development of cavitation based on improved cavitation model, Standard k-ε and RNG k-ε turbulence model. When cavitation flow and non-cavitation flow were simulated and analyzed, the pressure of blades under incipient cavitation, developed cavitation and serious cavitation were gotten. The paper also gave the principle of incipient cavitation and divided the region into five cavitation regions based on bubble relative length. The results show that with the decreasing of inlet total pressure, bubble appears firstly in suction surface of the blade, and then moves along the blade profile, and next forms attached cavitation bubble. After this stage, bubble is gradually out of the mainstream movement and close to the pressure surface. Finally, the flow passage is filled with bubble, which hinders the flow. The number σ=0.3067 of incipient cavitation is a greater dimension hierarchy than that of σ=0.0281 under design condition. Seen from the impeller meridian plane, bubble appears firstly in the near the hub, goes towards forward cover plate, and attaches near the front cover. Cavitation in centrifugal pump is subdivided again into the five stages, that are incipient cavitation, critical cavitation, developing cavitation, complete cavitation, broken cavitation. Source

Wei D.,Hohai University | Wei D.,North China University of Water Conservancy and Electric Power | Zhou H.,Hohai University | Zhou H.,China Energy Engineering Group Co.
Applied Mechanics and Materials | Year: 2014

For influence factors to engineering progress in project management of fund, resource allocation and climate etc, establish a schedule control model under the minimum cost. Using genetic algorithms for analysis, obtained the earliest start time of each working procedure at minimum costs. This method can avoid the impact of human factors and provides the powerful theory support for the policy-maker. © (2014) Trans Tech Publications, Switzerland. Source

Wang B.,Hohai University | Wang B.,Chongqing Three Gorges University | Zhou H.,Hohai University | Zhou H.,Chongqing Three Gorges University | And 2 more authors.
Shuili Fadian Xuebao/Journal of Hydroelectric Engineering | Year: 2015

This paper presents a relay chain network technology to consider mutual cooperation, cross construction, and resource allocation between working processes in the network plan, on the basis of the relay chain theory, relay chain seamless handover technology, and network planning technique. This technology can make activity handover conduct smoothly, optimize the resources allocation, and improve project quality in ensuring the duration. Its construction of relay chain network, relay-potential calculation, activity handover process, and critical path algorithm, are systematically elaborated. Its application to concrete construction duration and quality control in the third phase of the Three Gorges project has achieved a completion of the dam block A all reaching the design dam top elevation in advance to the planned duration, creating a construction miracle of concrete dam without a crack. ©, 2014, 10031243 Tsinghua University Press. All right reserved. Source

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