Applied Mechanics and Materials Vols. 316-317

Abstract: High level water tank is a commonly used facility to satisfy water demand for people living in high building, which is also the so-called secondary water supply system (SWSS) in China. Due to lack of maintenance, water quality problem has been frequently reported in the SWSS. In the last few decades, anti-negative pressure facility (ANPF) has emerged as a revolutionary approach for solving the pollution in the SWSS. ANPF makes good use of the municipal pipeline pressure, which is the improvement of traditional water supply. However, most of recent research activities mainly focus on the influence of part of water distribution system (WDS). In this paper, the software of EPANET has been applied in the SWSS calculation and simulation. Besides that, the SWSS with ANPF simulation method is proposed to evaluate the effect of other all nodes pressure in the WDS using hydraulic model. As the cases study, the paper analyzed two WDSs with ANPF. After simulation of the SWSS, the result of WDS, which is smaller, indicates that 6 out of the 9 nodes are affected with ANPF and that of WDS, which is larger, demonstrates that 37 out of the 41 nodes are affected and the affected nodes are focused on the confluent of pipes, especially around the ANPF.

Abstract: Water supply pipeline system is a key issue in urban lifeline engineering, and the seismic assessment for the system damage is of significant importance. In this study, method of seismic damage assessment on underground water supply pipeline is introduced. With emphasis on the uncertainties of earthquake level, ground condition, soil-pipe interaction and capacity to resist pipe deformation in longitudinal direction, the check point method is applied to the reliability study of water pipeline, and a case study is presented to show the implementation of the proposed model.

Abstract: Lately pipe bursts of urban water supply systems all over China could be learned briefly by analysis on news about water pipe bursts in Year 2010. Reasons about pipe bursts, relationships respectively between time, sites, materials, pipe diameters, pipe age and pipe bursts are discussed, and some serious water pipe bursts were introduced. Construction, aging, foundation change, temperature change, exclusive load, overpressure, engineering quality problems were main reasons for pipe bursts of this year.

Abstract: In order to evaluate the effective of the hydrodynamic control of pumps and slice gates in plain river network on the water quality improvement, an optimal mathematic model of hydrodynamic controlling on the pumps and slice gates in plain river network was established by combining the water quality objective function and the cost objective function together. The cost function has been set as the main objective function, while the water quality objective function was simplified as the restrained condition for every required water quality index, through which the multi-objective optimization was transferred into a single-objective optimization. Then, this optimal model was solved by coupling the water environmental model with the hybrid genetic algorithm. The case study of Jiaxing river network shows that the proposed hydrodynamic controlling optimal model in this paper can develop the optimal water diversion scheme for water quality improvement and cut its cost. It works better compared to the traditional water quality objective function and can be used in the engineering practice.

Abstract: Several issues impact environment sustainability, its evaluation index usually contains so high number of indicators and parameters that it is constrained in data-scarce regions where lack of consistent time series data especially. So, the assessment would just be carried on present situation, rarely on process. A water environment sustainability index for downstream marsh representing process was developed and proposed in this paper. Applied to Zhalong Wetland, the WESI scores the highest (3.47) at 1988 to the lowest (1.92) at 2005 that could be divided into 3 periods: 1980’s (good level), 1990’s (bad level) and 2000’s (rising up slowly under human manipulation). To maintain it at a good level, it is necessary to drain water from Nenjiang River year by year.

Abstract: Based on the fuzzy mathematics and analytical hierarchy process (AHP), the water quality was evaluated and analyzed according to 7 water pollution factors in 7 monitoring sections at the Dahuofang Reservoir which reflected the water quality at reservoir inflow, in reservoir area, and at reservoir outflow. The results show that: In 2010, the Dahuofang Reservoir was mainly polluted by nitrogen/phosphorus nutrient salts. Among the reservoir inflow, the Hunhe River was the most polluted. The water quality in reservoir area was mainly of Class II; the water quality at reservoir outflow was also of Class II, and was safe and reliable. According to the change of water quality monitoring value at three sections of Hunhe River (#73, #37 and #7) from 2005 - 2010, the pollution in the reservoir area had been effectively controlled, and the water quality in the reservoir area had been steadily improved.

Abstract: The adsorptive behavior of As(V) by using Fe-loaded D301(D301-Fe) was investigated under various conditions. The results indicated that As(V) strongly adsorbed at pH<10. Adsorption isotherm data could be better interpreted by Langmuir model. The kinetic data of the adsorption could be well described by the Lagergren second-order rate equation. equimolar addition of other anionic species such as SO2- 4, Clˉ and Fˉ had no influence on the adsorption of As(V), but PO3- 4 had a strong inhibition on As(V)

Abstract: Genetic algorithms (GA) are currently one of the state-of-the-art techniques for the optimization of engineering systems including water distribution networks design and rehabilitation. They are capable of finding near optimal cost solutions to these problems when certain cost and hydraulic parameters are given. Since many forms of GAs rely on random starting points, that is to say, the poor solutions, it has become an ongoing research topic how to efficiently provide good initial estimates of solution sets automatically. A novel method is proposed in this paper, known as two-step optimization, which uses a heuristic-based, Dijkstra arithmetic to optimize network topology to obtain the layout of main pipes. The first step provides a good pattern for subsequent GA runs. Two-step optimization is applied to a network.. The result shows that the proposed approach consistently outperforms the traditional design and the conventional non-heuristic-based GA approach in terms of convergence and calculation efficiency.

Abstract: The dipping tube hydropneumatic tank is one of the most efficient equipments to prevent water hammer in water distribution and long distance transmission pipe systems. Due to its low costs and easy to maintain features, dipping tube hydropneumatic tank has many irreplaceable advantages, however it is difficult to determine the correct size and gas volume for real world engineering applications. This paper presents a robust method to solve the problems from theory and application. Based on the Method of Characteristics (MOC) equations, this paper derives the equations for modeling dipping tube hydropneumatic tanks in water distribution systems to prevent water hammer. The equations include MOC, differential orifice head loss equation, gas law, air mass, air velocity and etc. The IBMs scientific subroutine package (SSP) is applied to solve the equations by deriving to the form of X=f (X). The method has been integrated into HAMMER. This paper also presents an example to illustrate the methods of determining the tank size, and the comparison results with sealed hydropneumatic tank and surge tank equipment.

Abstract: Gas channeling is tending to happen in CO2 immiscible flooding process, and that would seriously influence gas injection development. In order to plugging gas channeling channel effectively, improve inspiration and production profile, and enhance swept volume and oil displacement efficiency of the gas injection, field trials of foam seal channeling are carried out. The tests showed that carbon dioxide foam can effectively plugging the gas channeling channel, expand the swept volume of carbon dioxide gas, reduce invalid circulation, and enhancing oil displacement efficiency. The anti-sealing channeling technology is cost-efficient, and it is suitable for Daqing peripheral low permeability oil field on gas injection development. It has good prospects, and it will provide a strong technical support on gas injection development of low permeability reservoir.