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Gao J.-F.,Beijing University of Technology | Zhang Q.,Beijing University of Technology | Wang J.-H.,Beijing University of Technology | Wu X.-L.,Beijing Institute of Architectural Design | And 2 more authors.
Bioresource Technology

The contributions of loosely bound extracellular polymeric substances (LB-EPS), tightly bound EPS (TB-EPS), residual sludge (the sludge left after EPS extraction) and functional groups such as amine, carboxyl, phosphate and lipid on aerobic granules on biosorption of four different dyes (Reactive Brilliant Blue KN-R (KN-R), Congo Red (CR), Reactive Brilliant Red K-2G (RBR) and Malachite Green (MG)) were investigated. EPS may be responsible for biosorption of cationic dyes. However, residual sludge always made greater contribution than that of EPS. The biosorption mechanisms were dependent on the functional groups on aerobic granules and dyes' chemical structures. The lipid and phosphate groups might be the main binding sites for KN-R biosorption. Amine, carboxyl, phosphate and lipid were all responsible for the binding of CR. The lipid fractions played an important role for RBR biosorption. For MG, the phosphate groups gave the largest contribution. © 2010 Elsevier Ltd. Source

Zhu H.P.,Huazhong University of Science and Technology | Ge D.D.,Huazhong University of Science and Technology | Ge D.D.,Beijing Institute of Architectural Design | Huang X.,Huazhong University of Science and Technology
Journal of Sound and Vibration

Parameters of connecting dampers between two adjacent structures and twin-tower structure with large podium are optimized through theoretical analysis. The connecting visco-elastic damper (VED) is represented by the Kelvin model and the connecting viscous fluid damper (VFD) is represented by the Maxwell model. Two optimization criteria are selected to minimize the vibration energy of the primary structure and to minimize the vibration energy of both structures. Two representative numerical examples of adjacent structures and one three-dimensional finite element model of a twin-tower with podium structure are used to verify the correctness of the theoretical approach. On the one hand, by means of theoretical analysis, the first natural circular frequencies and total mass of the two structures can be taken as parameters in the general formula to get the optimal parameters of the coupling dampers. On the other hand, using the Kanai-Tajimi filtered white-noise ground motion model and several actual earthquake records, the appropriate parameters of two types of linking dampers are obtained through extensive parametric studies. By comparison, it can be found that the results of parametric studies are consistent with the results of theoretical studies for the two types of dampers under the two optimization criteria. The effectiveness of VED and VFD is investigated in terms of the seismic response reduction of the neighboring structures. The numerical results demonstrate that the seismic response and vibration energy of parallel structures are mitigated significantly. The performances of VED and VFD are comparable to one another. The explicit formula of VED and VFD can help engineers in application of coupled structure control strategies. © 2010 Elsevier Ltd. All rights reserved. Source

Zhang Y.,North China University of Technology | Chen E.,Beijing Institute of Architectural Design | Guo Z.,North China University of Technology
Advanced Materials Research

From the experimental research, the cube compressive strength and prism compressive strength of combined aggregate concrete are compared. Based on regression analysis, the influence of different substitution ratio of lightweight aggregate, age of concrete and water-cement ratio are studied, and the age coefficient is analyzed. According to the test results, the formula of compressive strength of combined aggregate concrete is given. © (2012) Trans Tech Publications, Switzerland. Source

Wang X.,Tsinghua University | Cheng R.,Tsinghua University | Zeng R.,Tsinghua University | Zeng R.,Beijing Institute of Architectural Design | Zhang Y.,Tsinghua University
Indoor and Built Environment

Optimizing the thermal physical properties of building envelope can decrease the energy consumption in active rooms. In this paper, a method of determining the ideal thermal mass characteristics of an active room wall has been developed, which can derive the optimal thermal physical properties of building walls by minimizing additional energy consumption. For demonstrating purpose, some illustrating examples are presented. The results show that: (a) the ideal specific heat distribution with temperature of the thermal mass for an active room approaches the δ function, which has the characteristic similar to that of phase change materials; (b) the thermal conductivity of internal wall has little effect on the optimized heat (cooling) load and the characteristic temperature when it is higher than 0.5 Wm-1 K-1 for the simulated room in Beijing. The additional heating and cooling energy consumption approaches zero when the excessive enthalpy of internal thermal mass is higher than 30 MJm-3 and 300 MJm-3 for Beijing in winter and summer, respectively, and the corresponding characteristic temperatures are 18°C and 26.3°C and (c) for practical use, the excessive enthalpy should be added in the internal thermal mass targeting both winter and summer performance in order to decrease the additional energy consumption. © The Author(s) 2013. Source

Ji X.,Tsinghua University | Jiang F.,Tsinghua University | Qian J.,Tsinghua University | Yang Y.,Beijing Institute of Architectural Design | Shi Z.,Tsinghua University
Jianzhu Jiegou Xuebao/Journal of Building Structures

This paper proposed an innovative composite wall, named the steel tube-double plate-concrete composite shear wall, which is suited for use in the lower stories of super high-rise buildings. The seismic behavior of the composite walls was examined through results of an experimental research program where five rectangle-shaped wall specimens with a shear span ratio of 2.5 were tested. The test results indicate that the specimens fail in a flexural mode, characterized by local buckling of boundary steel tubes and steel plates, fracture of steel tubes, and compressive crushing of concrete at the wall base. The extent of concrete filled steel tubular (CFST) boundary elements significantly affects the deformation and energy dissipation capacities of the composite walls. The area ratio of steel plate has a minimal effect on the deformation capacity of the wall specimens. The addition of circular steel tubes embedded in the CFST boundary elements leads to an increase in the lateral load-carrying capacity of the composite walls, but it does not increase the wall's deformation capacity. When the CFST boundary element's extent is 0.2 times the wall's sectional depth and the designed axial force ratio is 0.45, the wall specimen has a yield drift ratio of over 0.005 rad and an ultimate drift ratio of 0.030 rad. In addition, simplified formulas used to calculate the flexure strength of the composite walls were proposed. The evaluated results show good agreement with the test results, with errors no more than 10%. Source

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