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Cen L.H.,Central South University | Cen L.H.,Key Laboratory of System Control and Information Processing | Zhu H.L.,China Metallurgical Group Corporation
Applied Mechanics and Materials

This paper proposed a parameter identification method for simplified models of open drainage systems. SWMM is used to identify these parameters by taking the rainfall data as the input. Simulations show that the results of the proposed method have high accordance with those of SWMM. The drainage system of Duke University is taken as an example to demonstrate our approach. © (2013) Trans Tech Publications, Switzerland. Source

Li J.,Central South University | Li J.,Hunan Zhengyuan Institute for Energy Storage Materials and Devices | Yang J.,Central South University | Li L.,China Metallurgical Group Corporation | And 5 more authors.
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology)

The olivine type LiMn0.4Fe0.6PO4 was synthesized via the low temperature solid-state reaction combined with hydrothermal synthesis from Li2CO3, FeC2O4 · 2H2O, MnCO3 and NH4H2PO4. The product from the low temperature solid-state reaction was studied. The structure, particle size and surface morphology of these cathode active materials were investigated by XRD, SEM and TEM. Electrochemical characteristics of the composites were evaluated using galvanostatic charge/discharge tests. The results show that olivine LiMPO4 (M=Fe, Mn) is obtained after the raw materials are fired at 400°C for 4 h. All Li (Mn0.4Fe0.6) PO4 samples are simple pure olive-type phase with a conductive, thin web of carbon surrounding them. The composite synthesized via the low temperature solid-state reaction/hydrothermal synthesis has homogeneous particles of size 100 nm, an initial discharge capacity of 157 mA · h/g at 0.1C and a specific capacity of about 133 mA · h/g after 50 times cycling at 0.5 C rate. They are 1.07 times and 1.21 times of the products from the traditional solid-state, respectively. Source

Zhao Y.,University of Science and Technology Beijing | Gao J.-M.,University of Science and Technology Beijing | Yue Y.,University of Science and Technology Beijing | Peng B.,University of Science and Technology Beijing | And 4 more authors.
International Journal of Minerals, Metallurgy and Materials

Extraction and separation of nickel and cobalt from saprolite laterite ore were studied by using a method of microwave-assisted hydrothermal leaching and chemical deposition. The effects of leaching temperature and time on the extraction efficiencies of Ni2+ and Co2+ were investigated in detail under microwave conditions. It is shown that the extraction efficiencies of Ni2+ and Co2+ from the ore pre-roasted at 300 C for 5 h were 89.19% and 61.89% when the leaching temperature and time were about 70 C and 60 min, respectively. For the separation process of Ni and Co, the separation of main chemical components was performed by adjusting the pH values of sulfuric leaching solutions using a NaOH solution based on the different pH values of precipitation for metal hydroxides. The final separation efficiencies of Ni and Co were 77.29% and 65.87%, respectively. Furthermore, the separation efficiencies of Fe of 95.36% and Mg of 92.2% were also achieved at the same time. © 2013 University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg. Source

Guo G.,The MCC Group | Guo G.,China JingYe Engineering Co. | Liu Z.,The MCC Group | Liu Z.,China JingYe Engineering Co. | And 5 more authors.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering

The rupture surface of underreamed ground anchor is essentially important for the bearing mechanism of underreamed ground anchor. In order to observe the shape of rupture surface of sand around underreamed ground anchor during uplifting, a series of model tests on underreamed ground anchor under vertical uplifting were carried out with digital photogrammetry. For the first time, the whole deformation fields of underreamed ground anchor were captured through digital deformation analysis. The results show that the shear bands in the whole process exhibited as long and narrow vertical strips. The shear strain amplitude inside the rupture surface increased. During the process, the sand above the top surface of underreamed section exhibited volumetric compression; while the volume of sand on the side of underreamed section expanded. Based on the analysis, the damage model and bearing capacity calculation method of underreamed ground anchor should be established according to the rupture surface through actual observations. Source

Jia Y.,Beijing Jiaotong University | Meng X.,Beijing Jiaotong University | Zhang H.,China Metallurgical Group Corporation
Applied Mechanics and Materials

The geometric shape of buildings in wind field is an important influencing factor of wind pressure distribution on the buildings. Along with the change of roof shape, wind pressure distributions vary obviously. In this paper, the numerical simulation of the wind pressure for four types of large-span roofs is carried out, using CFX12.0 as computing platform. The characteristics of wind pressure distribution are studied by considering some parameters, such as wind direction, rise-span ratio, and terrain roughness. Wind pressure distribution is greatly affected by wind direction, and the wind pressure on large-span roofs is dominated by suction; the vortex shedding produced by airflow separation is the main factor affecting the characteristics of wind load. © (2012) Trans Tech Publications, Switzerland. Source

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