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He R.,Changan University | Zhou J.-L.,Changan University | Ji S.-H.,Architectural Design Research Institute of Guizhou | Chen S.-F.,Changan University
Chang'an Daxue Xuebao (Ziran Kexue Ban)/Journal of Chang'an University (Natural Science Edition) | Year: 2014

To investigate the spatial distribution of internal coarse aggregate in concrete, the random horizontal cross-section of the concrete specimen was processed by the digital image technology on its brightness transform, watershed segmentation and morphological operations. Then the precise 2-D concrete digital model was made based the processed image. The spatial distribution of coarse aggregate was analyzed by using two spatial distribution indexes, namely, shief axis slope and grade curve. The result shows that complete borderless images of concrete coarse aggregates can be obtained after the proper digital image processing, and the internal microstructure of concrete was characterized by these images. The chief axis slope of coarse aggregate nearly had the uniform distribution, with the average deviation of 14.8% from aggregated frequency curve in ideal state. The corrected digital image processing grading curve accords well with the design grading curve, with an average deviation of 5.78%. ©, 2014, Chang'an Daxue Xuebao (Ziran Kexue Ban)/Journal of Chang'an University (Natural Science Edition). All right reserved. Source


Yan W.-H.,Changan University | Wang C.-J.,Architectural Design Research Institute of Guizhou | Wu D.-H.,Changan University | Huang Z.,Changan University
Gongcheng Lixue/Engineering Mechanics | Year: 2016

To investigate wind-induced interference effects in folding camping tent groups, the blocking ratio was investigated using the software FLUENT, the models of which were based on fluid dynamic theory and atmospheric boundary layer theory. The blocking ratio was determined by a comparative analysis of numerical results and wind tunnel test data. According to the requirements of the tent installation and the passage width, both depth and width spacing were obtained. Meanwhile, regarding the wind direction and the space between tents as variable parameters, 75 conditions, including single tent, single column, and two columns of tents (with every column consisting of 6 tents) were simulated, and the amplification effect and shielding effect were derived accordingly. In addition, setting the maximum interference factor as the amplification factor, a shape coefficient was proposed, which is suitable for the wind-resistant design of folding camping tent groups and is based on the shape coefficient of single tent. The analysis in the present paper indicates that the wind-induced interference effect has significant implications for the design and the use of folding camping tent groups. © 2016, Engineering Mechanics Press. All right reserved. Source


He R.,Changan University | Ji S.-H.,Architectural Design Research Institute of Guizhou | Huang P.-M.,Changan University | Wang Z.-J.,Changan University
Chang'an Daxue Xuebao (Ziran Kexue Ban)/Journal of Chang'an University (Natural Science Edition) | Year: 2015

In order to study the effect of interfacial transition zone between coarse aggregate and cement mortar on the mechanics properties of concrete, the 2-D numerical concrete specimens were generated by using random aggregates model. With the adoption of interface constitutive relation on the basis of cohesive zone damage, numerical simulation of uniaxial compression and three-point bending experiments were performed to analyze the influence of interface strength between mortar and aggregate on the mechanics properties of concrete. The results show that the interface strength has a negligible influence on the compressive strength and elastic modulus of concrete when the heterogeneity factor is less than 0.7, and the compressive strength and elastic modulus increase greatly when the heterogeneity is greater than 0.7. The fracture energy of concrete demonstrates a linear increase relationship with the interface strength. The cracks propagate torturously along the interface zone during the fracture process. ©, 2015, Editorial Department of Journal of Chang'an University (Natural Science Edition). All right reserved. Source


Tang Z.,Architectural Design Research Institute of Guizhou | Yao X.,Architectural Design Research Institute of Guizhou | Lu T.,Guizhou University | Cheng G.,Guilin University of Technology | Wu Q.,Guilin University of Technology
Chinese Journal of Environmental Engineering | Year: 2015

During the “Eleventh Five-year Plan”, Guizhou Province launched a large-scale constructions of municipal sewage treatment plants. Most of the plants adopted mature technologies with nitrogen and phosphorus removal capabilities such as oxidation ditch, A/O process and SBR process and its variants process. Construction scale of sewage treatment plants is mostly below 0.5×104m3/d and running cost is mostly more than 0.60 yuan/m3. The unit construction investment, unit comprehensive energy consumption, the unit medicine consumption, sewage treatment rate and the processing load rate are 4 069.75 yuan/m3, 0.35 kWh/m3, 0.41 g/m3, 82.01% and 73.19%, respectively. The effluent quality can meet the first B class of emission standard of pollutants in municipal sewage treatment plant(GB18918-2002). However, the matching technology is one of the core problems in some sewage treatment plants. Therefore, it is advisable to strengthen the upgrading of sewage treatment technology and facilities in the “Twelfth Five-Year Plan” period. ©, 2015, Science Press. All right reserved. Source

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