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May 30,2015
Volume 8,Issue 10
Pages -
Subject Area:Fire Engineering,Aerial Photogrammetry,Heating and Gas Supply Engineering,Building Materials,Civil Construction Structure,Engineering Structures

Title: Experimental study on suppression of cup burner methane-air flame with bromofluoropropene

Authors: NI Xiaomin, KUANG Kaiqian, ZHAO Mei, ZHANG Shaogang
PP: 1096-1102
Abstract: This paper presented the study on the effectiveness and process of 2-bromo-3,3,3-fluoropropene (2-BTP) in suppressing cup burner methane-air coflowing flames, whose results were compared with those of bromofluoromethane (Halon1301) and 2-hexafluoropropane (FM-200). The minimum extinguishing concentration and the concentration of produced HF of the three agents were determined. The evolution of flame shape during extinguishing process was also investigated. Results showed that fire suppression effectiveness was ranked in the order of 2-BTP < Halon1301 < FM-200, and the produced HF concentration of the three agents was in the same order of 2-BTP Keywords: fire engineering; fire suppression; clean gas; cup burner; HF; extinguishing concentration

Title: Application of unmanned aerial vehicle low-altitude remote sensing in rural housing

Authors: CUI Yuanyuan, ZHENG Xinqi, FU Zongtang, AI Gang, ZHANG Xuewen, HU Kelin, CHEN Ping, ZHANG Pei
PP: 1088-1095
Abstract: Unmanned aerial vehicle low-altitude remote sensing showed many advantages such as high flexibility and high time efficiency, which made it applicable for data acquisition. Thus, a rapid and reliable workflow for rural housing land data acquisition based on unmanned aerial vehicle low-altitude remote sensing technology was proposed in this research. Four main steps were included: the preparation, field data acquisition, image processing and rural housing land information extraction. Meanwhile, a comparison with traditional method was conducted, through which the advantages of high-efficiency and low-cost of our workflow in data acquisition could be concluded. The workflow we proposed based on our research has good application prospect in rural housing land information acquisition, and can greatly improve the execution of real estate unified registration.
Keywords: aerial photogrammetry; unmanned aerial vehicle; rural housing land; cadastral survey

Title: Study on mining collapse disaster evaluation of shallow mining seam gully region

Authors: YU Xueyi, WANG Qi
PP: 1081-1087
Abstract: Based on analyzing the characteristics of mining collapse disaster in the special terrain condition of shallow mining seam gully region in Northern Shaanxi province, slough disaster is divided into avalanche, collapse, landslide and step crack. Taking Fengjiata Coal Mine in Northern Shaanxi province mining area as the engineering background, through analyzing the basic conditions of slough disaster, and combined with the experimental simulation results, related theory of analytic hierarchy process (AHP) is used to establish AHP evaluating model. It proposed that it should use coordinated mining, local limited height mining, partial backfill mining to slowdown the mining collapse disaster strength according to the disaster formation conditions. The results can provide scientific basis of mining collapse disaster prevention for similar mining conditions.
Keywords: mining engineering; shallow seam; gully region; collapse disaster; disaster prevention

Title: Study on microscopic flooding mechanism of the heterogeneous viscoelastic composites

Authors: ZHANG Bin, KANG Wanli, ZHAO Jian, XU Pingsheng
PP: 1076-1080
Abstract: A kind of preformed particle gel (PPG) with low elasticity and high viscosity was dispersed in polymer solution to form a combination flooding system. The transport behavior of the PPG through a porous medium and its microscopic flooding mechanism were studied by visual microscopic flooding model. The enhanced oil recovery capacity of the dispersed viscoelastic combination flooding system was also studied by chemical flooding simulation tests. The results show that transport behaviors of the PPG through a porous medium can be summarized in five patterns: direct passing through, adsorbed onto rock surface, trapped by throat, deformable passing through, snap-off and passing through. Its microscopic flooding mechanism includes selective conformance control, in-depth diversion, oil displacement of viscoelastic PPG and partially polymer flooding. The simulation experiments show that the oil recovery efficiency increases to 84.47% after the dispersed viscoelastic combination flooding system was injected, that is 37.83% higher than water flooding and 17.64% higher than polymer flooding.
Keywords: oil-gas field development engineering; heterogeneous; low elasticity and high viscosity; microscopic migration; microscopic displacement; oil recovery

Title: Stress analysis of ultra high voltage crossing tower

Authors: KONG Wei, WU Lin
PP: 1071-1075
Abstract: Three-dimensional map of the tower was obtained by using the TTA software. The tower three-dimensional map was imported into the finite element software ANSYS to carry out static analysis. Results of TTA softwere and finite element software ANSYS were contrasted to obtain the high secondary stress position of the tower which was the damaged location. Solution to reduce stress is proposed according to the stress characteristics analysis. The research provides a reference for the future design about the tower.
Keywords: other subject of basic subject of civil and architectural engineering; stress analysis; secondary stress; finite element method

Title: Study on the urban image design under the guiding of place theory: a typical example of Xi’an city

Authors: ZHANG Zhonghua
PP: 1062-1070
Abstract: Based on the perspective of the “sense of place” principle and the production principle of “locality” in the place theory, we analyzed the relevant coupled structures for urban image design and explored the basic characteristics, processes and laws for the creation of urban image, which will play a significant role in better designing of urban image. We think that creating of an urban environment with local style is the basic condition for inducing the sense of place for a city under the rapid urbanization development. The creation of sense of place for a city is the guiding objective and guiding value for urban image design. In the opinion of the author, a good urban image is corresponding with the “sense of belonging” and “sense of attachment” of the tourists and local people.
Keywords: method and theory of urban planning; place theory; image design; design countermeasure

Title: Steady-state simulation of multistage vertical-type absorption heat transformer

Authors: ZHU Chaoyi, XIE Xiaoyun, JIANG Yi
PP: 1053-1061
Abstract: Multistage vertical-type absorption heat transformer with LiBr-H2O solution as the working pair applied to the urban heat exchanger network stations was used as research object. By establishing a three-stage steady-state model through lumped parameter method, the changes in the liquid level and stability across the pressure of the large temperature difference multistage vertical-type absorption heat transformer in actual running conditions were simulated and studied. The results of the simulation provided advices and guides for pressure design in crew compartment and solution filling volume.
Keywords: heating and gas supply engineering; absorption heat transformer; multistage vertical-type; variable working condition; pressure gradient; solution quantity

Title: Optimal control and simulation of variable primary flow system

Authors: LUO Jinzhuo, LI Nan
PP: 1046-1052
Abstract: The variable primary flow system was a typical nonlinear, time variability and strong coupling of complex system. It was difficult to get an accurate mathematical model. Based on traditional PID control and fuzzy reasoning, the corresponding self-setting fuzzy PID controller was designed in this paper. By comparing the conventional PID control and self-setting fuzzy PID control simulation research of variable primary flow system, the results show that the self-setting fuzzy PID control possesses distinct advantages in overshoot, settling time and anti-interference performance in contrasted with the PID control.
Keywords: ventilation and air conditioning engineering; variable primary flow system; fuzzy PID control; simulation

Title: Experimental research on the maximum temperature of smoke near vault in metro tunnel fires

Authors: LIU Fang, CAI Jingpeng, LI Gang, WENG Miaocheng
PP: 1039-1045
Abstract: Relationships of the maximum temperature of smoke near vault in tunnel fires with longitudinal ventilation and heat release rate of fire was studied by small-scale experiments. The results show that longitudinal velocity and the heat release rate of fire has significant influence on longitudinal temperature of smoke near vault in tunnel fires. By comparing the test results of the maximum temperature of smoke with the predicted values using Kurioka model, a modified correlation is proposed by adding a metro tunnel corrected factor. The formula is recommended for the authority to use as a tool in evaluating the maximum temperature of smoke near vault in metro tunnel fires.
Keywords: ventilation and air conditioning engineering; metro tunnel fire; small-scale model; the maximum temperature of smoke

Title: Research on influence regularity of consistence in thermal insulation masonry mortar system

Authors: YUAN Zhen, QU Zongjiang, XU Fang, ZHANG Hao, YUE Tonglian, ZHAO Zongming, ZHANG Yunfeng
PP: 1032-1038
Abstract: In this study, P.O 325 grade ordinary portland cement was used as the main cementitious material with different size of quartz sand as aggregate and proper amount of fly ash as supplementary cementitious materials. Moreover, the early strength agent, plasticizer, water retaining agent, air entraining agent and other additives were mixed as masterbatch of A. The experiment adjusted the best mixture with water, and adjusted raw materials mixing ratio, and then optimzed the quality of mortar by testing. Finally the optimized formula weight (g/kg powder amount) was 200 g cement, 180 g fly ash, 20 g limestone, 600 g sand (containing 100 g coarse sand, 100 g medium sand and 400 g fine sand), 5 g masterbatch of A and 250 g masterbatch water. This formulation performance is the highest in the measured data chain through measurement. Therefore, it achieves the aim to optimize the thermal insulation mortar formula.
Keywords: non-metallic building materials; insulation masonry mortar; masterbatch; performance

Title: Feasibility study on restoration of concrete cracks by carbonic anhydrase microbial-induced mineralization

Authors: REN Lifu, QIAN Chunxiang
PP: 1022-1031
Abstract: A class of alkalophilic Bacillus was used. It can produce carbonic anhydrase (CA) which can promote reversible hydration reaction of CO2. The research shows that the bacteria has the ability to repair concrete cracks provided for abundent Ca2+. Test of growth curve by cultivation experiments determines that the optimal incubation time is 24-28 h and the optimal pH value is 8. With the pH value increasing, the growth capacity of bacteria and the activity of CA are both decreased. There are still viable bacteria which can maintain a certain enzymatic activity when the pH value increases to 12-13, which proves that the alkalophilic Bacillus is compatible with concrete. The bacteria has the ability to accelerate the deposition of CaCO3 in the solution. Further tests verify the bacteria has the ability to repair concrete cracks by CA microbiologically precipitation CaCO3 when providing adequate Ca2+ in concrete.
Keywords: building materials; materials science; carbonic anhydrase; concrete; cracks; repair

Title: Numerical analysis of the iced transmission line galloping

Authors: QIN Li, XU Tianyuan
PP: 1014-1021
Abstract: Assumed mode method had been used to simulate the iced transmission line galloping. Three generalized coordinates represented the iced transmission line galloping. In order to avoid complicated calculation of vector, the Lagrange equation had been used to build the nonlinear equations of iced transmission line from the perspective of energy. The Runge-Kutta numerical calculation had also been used to solve the equations of motion and get the across-wind, along-wind and torsional response of iced transmission line. Based on the first Lyapunov stability theory, the critical wind speed formula of the iced transmission line galloping was deduced. The feasibility of the numerical solution and the critical wind speed had been verified by using a test iced transmission line.
Keywords: civil construction structures; iced transmission line; galloping; Runge-Kutta; critical wind velocity

Title: Wind vibration response analysis of transmission tower-line system in consideration of the pile-soil-structure dynamic interaction

Authors: DENG Xiao, YAN Zhixin
PP: 1007-1013
Abstract: In order to study the effect of pile-soil-structure dynamic interaction on the wind vibration response of transmission tower-line system, the finite element model of pile-soil-transmission tower coupled system was set up by ANSYS. The fluctuating wind loads simulated by Matlab according to autoregressive (AR) method was forced on the model in order to analyze the wind vibration response. The wind vibration response of a pile-soil-transmission tower system under two different site conditions (soft soil and hard soil) were calculated, and compared with the result that does not consider the effect of pile-soil-structure dynamic interaction. From the comparison, the influence of pile-soil-structure dynamic interaction on wind vibration response of transmission line system has been concluded.
Keywords: civil construction structures; wind vibration response; numerical simulation; transmission tower-line system; pile-soil-structure dynamic interaction

Title: Dynamic seismic performance analysis of the prefabricated high-rise frame structure

Authors: LIU Shibin, DUAN Lei
PP: 999-1006
Abstract: Taking a nine stories prefabricated reinforced concrete frame structure as the engineering background, this paper conducts the analysis of dynamic elastoplastic in order to study the seismic performance of this frame. With the time-history analysis method, the author considers the structural layer shear, the layer displacement and the drift angle, these data meets specification requirements, and the seismic performance of the high-rise structure is perfect. Under the same conditions, the author calculates the seismic performance of in-situ reinforced concrete structures as well. Comparison shows that embedded steel enhances seismic shear resistance under strong earthquake.
Keywords: engineering structures; precast fabricated; time analysis; seismic analysis

Title: Experimental study of damage identification of a continuous beam bridge model using an adaptive approach

Authors: HUANG Hongwei, SUN Limin
PP: 990-998
Abstract: In this paper, a newly proposed data analysis method for structural damage identifications, referred to as the adaptive approach, was studied using a continuous beam bridge structure. The finite element model of the bridge was established and experimental study was carried out with limited number of measured response data. The acuracy and capability of the proposed approach in identifying the structural damage is verified.
Keywords: engineering structures; bridge engineering; structural health monitoring; adaptive approach; damage identification of structures

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