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The shafting vibration for the Hydraulic-Turbine Generator Unit (HGU) inevitably affects the safe and stable operation of the Units. Excessive shafting vibration could cause fatigue damage of materials, which eventually leads to malfunction of HGU and even results in damage accidents in serious cases. Generally speaking, the vibration is mainly generated from the high-speed rotation of the shafting, and mechanical, hydraulic, and electrical factors as the vibration exciting sources may be coupled all to cause a vibration of the HGU, so it is necessary to take the whole shafting as a specific object of study. In recent years, many scholars have conducted much research on them and their results are focused more on how to control the influence of external excitation sources of vibration, but still lack consideration of the shafting's internal mechanism of vibration. In this paper, a predictive analysis method is proposed to reveal the internal mechanism of vibration. Starting from the analysis of natural vibration characteristics of the shafting, this study establishes the finite element calculation model of the shafting of the HGU based on the finite element analysis method. By selecting appropriate research methods and calculation procedures, the modal analysis of the dynamic characteristics of the shafting structure is carried out. Finally, the first ten-order natural vibration characteristics and critical rotational speed of the shafting structure are successfully calculated, and the results conform to the basic laws of shafting vibration. In addition, by comparing the relationship between rotational frequency such as the rated speed, runaway speed, and critical speed of the shafting, the possibility of resonance of the HGU is analyzed and predicted, and then some suggestions for optimization design such as increasing the shafting's stiffness and balancing its mass distribution are proposed. Therefore, this study provides a basis for guiding the structural design and optimization of the shaft system in engineering, and avoids the resonance caused by the excitation source such as rotational frequency, thereby ensuring the safe and stable operation of the HGU. [ABSTRACT FROM AUTHOR]

This paper presents a nested approach for generating long-term, medium-term, and short-term reservoir scheduling models, which is based on the actual needs of the scheduling operation of the Three Gorges–Gezhouba (TG-GZB) cascade reservoirs. The approach has established a five-tier optimal scheduling model in which the time interval of the scheduling plan prepared by the model can be as short as 15 min, meeting the real-time scheduling requirements of the cascade hydropower station system. This study also presents a comparatively comprehensive introduction to all solving algorithms that have ever been adopted in the multi-time scale coordinated and optimized scheduling model. Based on that, some practical and efficient solving algorithms are developed for the characteristics of the scheduling model, including the coupled iterative method of alternating reservoirs (CIMAR)—the improved dynamic programming (IDP) algorithm and the improved genetic algorithm (IGA). In addition, optimized-scheduling solutions were generated by each of the three algorithms and were compared in terms of their convergence rate, calculation time, electric energy generated, and standard deviation of the algorithm. The results based on the Cascade Scheduling and Communication System (CSCS) of Three Gorges–Gezhouba, China, which includes two interlinked mega-scale reservoir projects, show that scheduling models have better efficiency and good convergence, and more importantly, the maximization of the power generation benefits of the hydropower plants has been achieved without violating any of the reservoir scheduling regulations. [ABSTRACT FROM AUTHOR]

A novel model has been proposed for the methodical development and safe utilization of the lower Yellow River floodplain to provide flood control with a graded standard, sediment deposition in the partitioned zone, and the free exchange of channel runoff and sediment. The wide floodplain, which is located between the dam and the main channel, has been typically divided into three zones: high, tender, and low floodplains. Meanwhile, different ecological construction models have been suggested for each zone. This paper summarizes all related research findings; describes the overall research ideas and methodologies; expounds key issues such as land planning and utilization, sediment prediction and regulation, and multi-dimensional industrial safeguards in the lower Yellow River floodplain; and provides orientation for future research on the ecological development of the lower Yellow River floodplain. This study aims to promote the refinement of the ecological development model for the lower Yellow River floodplain and accelerate the application of research findings regarding land development and utilization of the lower Yellow River floodplain. [ABSTRACT FROM AUTHOR]

This study proposes a novel method to improve the fault identification performance of transformers. First, to couple multiple factors, a high‐dimensional feature map composed of the feature gas concentrations and some associated variables is constructed. Second, the deep residual shrinkage network is revised using the updated alternating direction multiplier, and the newly constructed variable soft thresholding is proposed to eliminate constant deviations. In addition, the fast iterative shrinkage‐thresholding algorithm is adopted, as it can speed up the determination of the threshold. For the output end, the uniform manifold approximation and projection algorithm are adopted to ensure the integrity of the local optimal solution and the global solution. Compared with traditional dissolved gas analysis methods, the novel refined deep residual shrinkage network exhibits superior precision, which is justified through experiments. The results show that the recognition accuracy of the new model is more than 1.3% higher than that of the existing methods. The new method has good scalability in power applications and fault prevention. [ABSTRACT FROM AUTHOR]

Copyright of Irrigation & Drainage is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A method is presented for optimal load dispatch in large-scale hydropower plants using a genetic algorithm integrated with simulated annealing. The genetic algorithm overcomes dependence on an initial value and provides parallel processing and fast convergence, whereas simulated annealing prevents prematurity and retrieving of the local instead of the global optimum. Thus, the integrated genetic-simulated annealing algorithm improves efficiency and robustness to obtain solutions close to the global optimum. We evaluated the proposed algorithm to determine the optimal load dispatch of 32 units of the Three Gorges Hydropower Plant in China. Test results show that the minimum water consumption obtained using the proposed algorithm is similar to the optimum obtained from a previously proposed "improved" genetic algorithm when the total load of the plant is relatively high. However, for reduced load, the proposed algorithm clearly outperforms the "improved" genetic algorithm. [ABSTRACT FROM AUTHOR]

The particle filter‐based data assimilation method is an effective tool to adjust model states based on observations. In this study, we proposed a modified particle filter‐based data assimilation method with a local weighting procedure (MPFDA‐LW) for a high‐precision two‐dimensional hydrodynamic model (HydroM2D) in dam‐break flood simulation. Moreover, a particle filter‐based data assimilation method with a global weighting procedure (PFDA‐GW) for the HydroM2D model was also investigated. The MPFDA‐LW and the PFDA‐GW for the HydroM2D model, respectively, adopted spatially nonuniform and uniform Manning's roughness coefficients. The MPFDA‐LW considering spatial‐temporal variability of Manning's roughness coefficient could significantly improve the performances of the HydroM2D model in simulating water stages at all gauges simultaneously, whereas the PFDA‐GW considering temporal variability of Manning's roughness coefficient could only slightly improve the performances of the HydroM2D model in simulating water stages at a few gauges. The MPFDA‐LW is more suitable for improving the performance of 2‐D hydrodynamic models in flood inundation simulation than the PFDA‐GW. Key Points: We proposed a data assimilation framework for a high‐precision 2‐D hydrodynamic model (HydroM2D) based on a modified PF methodThe PF‐based data assimilation (PFDA) method for the HydroM2D model considered the spatial‐temporal variability of Manning's roughness coefficientThe PF‐based data assimilation could simultaneously improve the performances of the HydroM2D in simulating water stages at all gauges [ABSTRACT FROM AUTHOR]

As a complicated water treatment system project, an urban water supply plays a significant role in enhancing ecological civilization construction, promoting social-economic sustainable development, and improving the living environment of humans. This paper has the goal of improving water treatment efficiency and reducing water treatment cost based on comparative studies by applying two types of distributed database query optimization methods, including the system for a distributed database (SDD-1) and all reduction algorithms. The approach involves the components of partial relations and deletes the database components that are unrelated to a query, using only attributes related to a query. Thereby, the realization process becomes simple, with a small amount of transmitted data. The results show that the validity and convenience of all reduction algorithms involve the whole query process. An algorithm is independent of the chart of static characteristics and can realize all reduction states without depending on analyzing the benefits from intermediate semijoin results, which will ultimately contribute to reductions in the transmission of useless data in the network and communication costs. Implementation of the query optimization strategy can improve water treatment efficiency, reduce water treatment cost, lower water treatment expense, and implement effective communication. [ABSTRACT FROM AUTHOR]

The Middle Route of the South-to-North Water Diversion Project is important for China. Any sudden water pollution accident along the route would threaten normal water supply. We studied four technologies (hydrodynamic and water quality simulation, source identification, emergency regulation, and evaluation of emergency measures) and developed and implemented a decision support system that provides technical support in managing pollution accidents. The achievements, which include four technologies and a system, have practical significance for emergency management in the Middle Route as they can help deal with accidents and policy formulation, and can be applied to other water transfer projects. [ABSTRACT FROM AUTHOR]

This study proposes and tests a new approach to detect and analyze changes in flood regime using a distributed hydrological model (EasyDHM), using the Second Songhua River basin, China, as a case study. Model calibration and parameter sensitivity were used to represent flood regimes in a 60-year series (1954-2013), with three different flood regime periods identified. The changes in flood regime were estimated by model parameters, flood result residuals and the overall process in the hydrological model in the three periods. The results show that human activities significantly impacted flood regimes, with significant flood regime change largely attributed to increases in water storage in multiple small reservoirs. Flood volume was reduced significantly between the periods in all three watersheds. The parameters also changed in variety between the periods. The study highlights the importance of incorporating data on small-reservoir constructions in flood control systems. [ABSTRACT FROM AUTHOR]

Flash floods cause extensive loss of property and human life. Early warning systems present a more efficient approach to flood prevention and mitigation than engineering measures. This article reviews research on flash flood early warnings in China, including long-term prediction methods based on statistical regularity and flood mechanisms, and real-time warning indicators relying on multi-source data and automated systems. Current research shortcomings are discussed, and suggestions for future improvements are proposed. This research can provide public officials with knowledge of flash flood early warnings, influencing policy and protecting people from flash flood disasters. [ABSTRACT FROM AUTHOR]

The joint operation of cascaded reservoirs can generate various compensation benefits. How to calculate all compensation benefits scientifically and fairly, and how to share these benefits reasonably, will be of great importance for the sustainable development of the basin and for the rolling development of a cascaded reservoir of a hydropower station. This article examines the joint operation of Longyangxia and Liujiaxia reservoirs at the upper reaches of the Yellow River in China. To study the reservoir compensation benefits, the authors have built a compensative regulation model for the joint operation of the reservoir group. The electricity generation compensation economic effects of the joint operation of the Longyangxia and Liujiaxia reservoirs in 2005 were calculated. The results showed that the joint operation of cascaded reservoirs can generate remarkable economic benefits. [ABSTRACT FROM AUTHOR]

Summary: Resource volatility is a major challenge on desktop grid platforms with characteristics that primarily depend on human computer usage behavior. This study proposes a trust model based on Dempster–Shafer theory that predicts the relative reliability of nodes using information on daily computer usage behavior based on the historical information from a desktop grid platform for a desktop grid. In the proposed trust model, called TM‐DG, a degree of trustworthiness is introduced for the nodes to quantify their reliability. Dempster's rule of combination is also applied to exploit two bodies of independent evidence: 1) current node availability as actively probed by a special test node and 2) proportion of allocated tasks successfully completed. The simulations performed on a lightweight desktop grid platform illustrate how TM‐DG can fully utilize the most reliable nodes for a given computation, leading to a reduction in the communication overhead and an improvement in the computing power of the platform. [ABSTRACT FROM AUTHOR]

Danjiangkou Reservoir is the source reservoir of the Middle Route of the South-to-North Water Diversion Project (MRP). Any sudden water pollution accident in the reservoir would threaten the water supply of the MRP. We established a 3-D hydrodynamic and water quality model for the Danjiangkou Reservoir, and proposed scientific suggestions on the prevention and emergency management for sudden water pollution accidents based on simulated results. Simulations were performed on 20 hypothetical pollutant discharge locations and 3 assumed amounts, in order to model the effect of pollutant spreading under different reservoir operation types. The results showed that both the location and mass of pollution affected water quality; however, different reservoir operation types had little effect. Five joint regulation scenarios, which altered the hydrodynamic processes of water conveyance for the Danjiangkou and Taocha dams, were considered for controlling pollution dispersion. The results showed that the spread of a pollutant could be effectively controlled through the joint regulation of the two dams and that the collaborative operation of the Danjiangkou and Taocha dams is critical for ensuring the security of water quality along the MRP. [ABSTRACT FROM AUTHOR]

Remote sensing has been recognized as an effective tool to monitor water quality in inland waters. An adaptive model coupled with a modified discrete binary particle swarm optimization algorithm utilizing the catastrophe strategy and partial least squares (MDBPSO-PLS) was developed to retrieve the water quality indexes (chlorophyll a (chl- a ), total suspended matter (TSM), and turbidity) in Weishan Lake. Based on the selective bands for water quality retrieval, the proposed MDBPSO algorithm was compared with original DBPSO and Genetic Algorithm (GA) in order to validate the feasibility and efficiency of the proposed algorithm. The comparison results indicated that MDBPSO with the catastrophe strategy could avoid the premature convergence phenomenon of DBPSO algorithm. The hyperspectral data from HJ-1A Hyperspectral Imager (HSI) selected by MDBPSO were utilized to establish the PLS model by correlating the spectral data with measured water quality parameters. Then the established PLS model was compared with the PLS model established with full spectral data and measured water quality parameters. MDBPSO-PLS showed the better performance in retrieving the above-mentioned three parameters in Weishan Lake. The comprehensive errors between measured and retrieved parameters in MDBPSO-PLS (chl- a ( R 2  = 0.97, CE  = 3.16%), TSM ( R 2  = 0.97, CE  = 5.84%), and turbidity ( R 2  = 0.97, CE  = 7.40%)) were lower than those in PLS model (chl- a ( R 2  = 0.55, CE  = 18.71%), TSM ( R 2  = 0.49, CE  = 49.50%), and turbidity ( R 2  = 0.50, CE  = 50.46%). The three water quality parameters were mapped by using MDBPSO-PLS. Our observations indicated that the MDBPSO-PLS model showed the significantly higher retrieval accuracy than the PLS model and could provide realistic information on the distribution of chl- a , TSM, and turbidity in Weishan Lake based on HJ-1A HSI. [ABSTRACT FROM AUTHOR]

This study identifies the driving forces behind maximizing Tianjin’s industrial water use efficiency in China. For this purpose, a decomposition method is developed to quantify the degree of the impact of each factor. The results show that industrial expansion was responsible for an increase in annual water use of 78 million m³, while technical advances and water efficiency measures contributed annual water savings of about 76 million m³. Further, the results highlight that Tianjin has not considered the rise in water efficiency to be the primary goal of restructuring local industries over the past decade. [ABSTRACT FROM PUBLISHER]

At present, the urbanization and energy consumption complex system enters the stage of ultimate development. So it is not certain about synergistic development. From the perspective of causal feedback mechanism system and based on the mechanism of various elements of urbanization and energy consumption, this paper explores the path of synergistic development of urbanization and energy consumption, simulates the baseline scenario from 2005 to 2020 through establishment of the SD model of urbanization and energy consumption complex system, predicts the future behavior of the state variable when the control variable changes in the system through simulation, seeks for interaction and interrelationships between various elements in the process of evolution and development, and finally puts forward three paths to optimize the synergistic development of urbanization and energy consumption which are population transfer, industrial upgrading and technological improvement, which provides some references and foundation for making decisions of synergistic development of new urbanization and energy consumption. [ABSTRACT FROM AUTHOR]

Copyright of Irrigation & Drainage is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Many new cities have developed in China in recent years and older cities have expanded substantially. These newly built urban areas incorporate vast expanses of water landscapes for aesthetic purposes and enhance the quality of the living environment. Considering the uneven distribution of water resources in China, concerns have been raised over the impact of creating such large-scale water surfaces on ecosystems of the country's northern arid region. The methods for creating surface water bodies in the arid cities of northern China are examined and the internal driving factors are analyzed. The authors advocate that these cities should exercise caution when creating artificial water landscapes and that such projects must be scientifically sound. [ABSTRACT FROM AUTHOR]

Beijing's local water resources have been overexploited and the ecological and environmental pressures exceed the carrying capacity of this densely populated megacity. This article examines the current status of Beijing's water resources with respect to its industrial, residential, and eco-environmental water usage and the challenges it may face in the near future. The article describes the context of water uses, the steps taken by Beijing to alleviate the water shortage problems, and challenges to Beijing's abilities to meet its urgent and future water needs. A multipronged strategy is proposed that aims at both the present problems and the anticipated future challenges. In particular, engineering and institutional approaches for Beijing's successful transition from overexploitation to sustainable utilization of water resources are explained. Actions include reasonable water utilization, water conservation, reclaimed wastewater, and importing water from neighboring areas. We conclude that Beijing must take additional steps in water resource management to ensure its sustainable development that involves continued urbanization sprawls and population growth. Future water resource management strategies should focus on strengthening water demand management through water conservation, efficient interbasin water transfers, use of nontraditional water resources, strategically reserving water supply, and promoting rehabilitation of the eco-environments. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the authors discuss several article within the issue on topics which include water challenges for megacities in Asia and North America, water demand and scarcity in Beijing, China, and water quality model.