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Zhang G.,Changan University | He S.-H.,Changan University | Guo H.-J.,Xian Municipal Engineering Design & Research Institute Co. | Hou W.,Changan University
Applied Mechanics and Materials | Year: 2012

The deflection for pre-stressing concrete thin-wall box girders bridges under action of multi-span loads exposed to fire was presented in this paper. Based on thermal and mechanics parameters, the fire and load model was designed, the space analysis procedure was performed to analyze the maximum deflection of each span during prophase and anaphase of extending-fire time, altogether 4 kind of load case. The studied results indicate: Under condition of the whole span fire and load model of multi span, the mid-span deflection of the second span is down-warping during the fire prophase which its time is about 20 minutes, and up-warding or horizontal during the fire anaphase which its time is about 50 minutes; the deflection of the first and third span is down-warping with extending time during the whole fire time. © (2012) Trans Tech Publications, Switzerland. Source


He R.,Changan University | Li Y.-P.,CAS Zhengzhou Research Institute | Ren S.-R.,Xian Municipal Engineering Design & Research Institute Co. | Wang Z.-J.,Changan University
Huanan Ligong Daxue Xuebao/Journal of South China University of Technology (Natural Science) | Year: 2015

In order to overcome the poor bond performance of macro-synthetic polypropylene fiber/cement matrix, macro-synthetic polypropylene fiber was soaked in polyacrylamide solution, and fiber pullout test, microhardness test, X-ray diffraction analysis and scanning electron microscopy analysis were subsequently carried out to evaluate the effect of polyacrylamide on the interfacial properties of fiber/cement matrix. The results show that fiber/matrix interfacial bond properties improve due to the treatment with polyacrylamide solution; for instance, the fiber pullout curve becomes fuller and the interfacial debond postpones. Moreover, significant improvement can be observed with the increase of polyacrylamide content in the solution. It is also found from microanalysis that the treatment results in a decrease of CH crystal in the interfacial region, an increase of interface microhardness, a thinner transition layer as well as a densified hydration products structure with alternate CH, C-S-H and AFt. Thus, the weak area between the fiber and the cement matrix improves significantly. ©, 2015, South China University of Technology. All right reserved. Source


Dou Y.,Xian University of Architecture and Technology | Wang Y.,Xian University of Architecture and Technology | Huang R.,Xian University of Architecture and Technology | Du H.,Xian University of Architecture and Technology | And 2 more authors.
Chinese Journal of Environmental Engineering | Year: 2016

The supernatant of a waste sludge treatment system (or reject water) was rich in phosphorus and nitrogen, and its recycling always led to unstable effluent in the wastewater treatment plant. In this study, a fluidized bed reactor with tube-in-tube was employed to crystallize struvite from treatment reject water by CO2 stripping and addition of magnesium salts. The effect of the gas-water ratio on the removal of phosphorus and nitrogen was studied, and further research on the quantity, distribution, morphology, size, and components of the crystal products was pursued. The results showed that the removal rate of phosphorus and nitrogen, as well as the pH, increased, while the alkalinity decreased, with increase of the gas-water ratio. When the gas-water ratios were 15:1, 30:1, and 60:1, the removal rates of phosphorus in the reject water were 73%, 82%, and 87%, respectively, and about 17% to 23% of nitrogen was removed. On the other hand, the gas-water ratio also influenced the quantity, distribution, and size of the crystal products, but had little effect on the morphology and components of the crystals. However, there was a recognizable difference between the crystals formed at the bottom and those formed on the inner wall of the reactor. The former crystals were in smaller pieces and the latter were formed as larger cuneiform. Despite the size difference, XRD analysis revealed that both the crystal products were mainly struvite. © 2016, Science Press. All right reserved. Source


Ren Y.,Xian University of Technology | Jiang H.,Xian University of Technology | Jiang H.,Xian Municipal Engineering Design & Research Institute Co. | Lin X.,AVIC Xian Aircraft Industry Group Co.
Xi'an Jianzhu Keji Daxue Xuebao/Journal of Xi'an University of Architecture and Technology | Year: 2016

To enhance the mixing effectiveness of water and agent and to improve the efficiency of water treatment, the numerical simulation and hydraulic characteristics of a funnel vortex reactor by the hydraulic mixing were studied. The results showed that the stable vortex could be obtained by means of the tangential inflow and height difference between inlet and outlet of the reactor. The aditus laryngis could effectively enhance the backmixing function. The flow regime was between continuous flow and plug flow, and the mixing efficiency was only dependent on the velocity of inflow. When the inlet velocity ranged from 0.1 m/s to 1.5 m/s, the vortex size was close to the diameter of agents particle, in favor of the collisions and mixing among the vortex. The best effects of mixing could be achieved when the inflow velocity was 0.2 m/s. Meanwhile, the reactor only needed to be controlled by the pump, and then the energy consumption would decreased considerably. © 2016, Science Press. All right reserved. Source


Zhao X.,Rural University | Zhao Y.,Rural University | Zhao Y.,University College Dublin | Wang J.,University College Dublin | And 7 more authors.
International Journal of Environmental Studies | Year: 2015

A ‘fan-shape’ constructed wetland (CW) system is designed to treat domestic wastewater as well as to provide an aesthetically pleasing and environmentally sensitive landscape with ornamental plants for recreation. The system consists of two-stage subsurface horizontal flow CW cells with dewatered alum sludge cakes as the main substrate to ensure the treatment efficiency. The system is located in a new countryside village in Northwest China. The paper presents the design considerations of the CW together with the surrounding landscape to create an integrated CW (ICW). The study attempts to show how the wastewater infrastructure of CW can be an attractive feature in a community; bringing utility and beauty together, and serving needs for education, recreation and habitat conservation, through integrating engineering and landscape design. © 2014 Taylor & Francis. Source

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