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This paper presents an analytical investigation of water hammer in a hydraulic pressurized pipe system with a throttled surge chamber located at the junction between a tunnel and a penstock, and a valve positioned at the downstream end of the penstock. Analytical formulas of maximum water hammer pressures at the downstream end of the tunnel and the valve were derived for a system subjected to linear and slow valve closure. The analytical results were then compared with numerical ones obtained using the method of characteristics. There is agreement between them. The formulas can be applied to estimating water hammer pressure at the valve and transmission of water hammer pressure through the surge chamber at the junction for a hydraulic pipe system with a surge chamber.

In this paper, we shall prove that for any orientable 3–manifold M, there is a link L = K ∪ K 1 ∪ K 2 ∪ K 3 with four components in M, such that the complement of L, say M L , contains separating essential closed surfaces of all positive genera. [ABSTRACT FROM AUTHOR]

It is already known that finitely-generated Fuchsian groups are profinitely rigid among all lattices of connected Lie groups by the result of Bridson, Conder and Reid. Hence the triangle groups are distinguished among themselves by their finite quotients. We focus on the question about quantifying the size of a quotient which separates two triangle groups and give an explicit upper bound. [ABSTRACT FROM AUTHOR]

A new method to set up the static magnetic field of the targeted magnetic fluid hyperthermia is presented, and a new particle swarm optimization algorithm with Levy flight (LF-PSO) is proposed. Magnetic field generating system consists of 18 coils, deployed in the lesions of the peripheral symmetric space, the main principle is to heat magnetic nanoparticles by high frequency alternating magnetic field to kill the cancer cells, while building a static magnetic field in the periphery of the tumor region to protect healthy tissue from harm. Tumor location information may be shifted, so each treatment needs to reconfigure the static magnetic field. The set of magnetic heating coil currently adopted this new LF-PSO algorithm, in the reason of the particle swarm optimization algorithm with Levy flight mechanism is characterized by good robustness, high precision of optimal search and it is easy to jump out of local optimum. Experimental results show that by building a new objective function, and comparing with the FEM algorithm, the LF-PSO algorithm has advantages of fast solving speed and high accuracy. [ABSTRACT FROM AUTHOR]

In regulated freshwater ecosystems, the deposition process of organic carbon (OC) in sediment could be affected by all the changes of physical, chemical, and biological factors. To assess different hydrodynamic conditions on the deposition of OC in sediment, the combination of elemental and stable isotope analyses was carried out in two reservoirs: the Huairou Reservoir (HR), which undergoes seasonal water level fluctuation (WLF) like natural lakes, and the Shisanling Reservoir (SR), which undergoes daily WLF for the operation of pumped storage power station. In general, OC concentration and its variation were comparable in the two reservoirs, whereas the OC distribution showed completely different features. The OC burial rate in SR was nearly two times more than in the HR, which reflect the impact of WLFs on the erosion of soil. For the relative contribution of phytoplankton-derived OC (P-OC), macrophyte-derived OC (M-OC), and terrestrial OC (T-OC) in sediment, the T-OC and M-OC in the SR were both higher than those of the HR, whereas the P-OC was markedly lower. Furthermore, the classification of nearshore and offshore sediments suggested that hydrodynamic conditions affected the T-OC import by physical processes and the in situ contributions of P-OC and M-OC with a spatial difference. [ABSTRACT FROM AUTHOR]

China is arguably one of the countries where the most tunneling and underground projects are being performed. Recently in China, it has often been necessary to construct tunnels under many types of conditions and to develop new techniques. Currently, some advanced construction techniques cannot be appropriately applied to different types of underground conditions, and many traditional methods are still often used. However, because of the progress in tunnel boring machines(TBM), innovations are required for the construction method. This article introduces the current situation of TBM both in western countries and in China, and examines the future of TBM in China. [ABSTRACT FROM AUTHOR]