Abstract:The bolt-sphere joint belong to the semi-rigid node, whether it can be applied in the single-layer reticulated shells is one of the key problems which is badly in need of being solved in this field. This paper based on the finite element analysis and took advantage of the results of tests of bolt-sphere joints. The moment-rotation curves of bolt-sphere joints are obtained from, then through introducing the node stiffness simulation of shell into the numerical methods, the analysis method of semi-rigid node net shell were set up. On this basis, specific to citizen fitness center in the north new district of shen yang, which is an 80m diameter reticulated spherical shell with bolt-sphere joints, and the nonlinear stability of the different form during the work progress were analyzed, the skin effect of single-layer reticulated spherical shell with bolt-sphere joints were discussed. The result shows that during construction phase, the bending is the major stress form of the part of the reticulated dome’s bars, which result in the ultimate bearing capacity of 1／2 dome under horizontal load is the lowest, and because of the big deformation of dome’s upside, the ultimate bearing capacity of 3／4 dome under vertical load declines largely. After the dome is closed, the bending bars are transformed into being major suffered with axial force, its ultimate bearing capacity reach the 4.7 times of design load under vertical load and 9.2 times under horizontal load, therefore only to adopt rational measures and avoid the buckling failure during the construction phase,the bolt-sphere joints can be applied into the single-layer reticulated shell.

Abstract:In order to obtain the response characteristics of LNG (liquefied natural gas) containment tanks under wind load, an accurate model of a 160 000 m³ LNG tank is established based on practical engineering. Finite element analysis via ANSYS is conducted considering static wind and along-wind vibration. Comparison is made between the Fourier series for wind pressure distribution of cylinders supposed by foreign scholars and shape coefficients for wind pressure distribution of circular section structures adopted by Chinese load code for the design of building structures. Wind pressure height coefficients are also compared between Chinese code and U.S code. It is proved that the coefficients adopted by Chinese load code are more adverse for the LNG tank. The results of deformation and stress in different wind directions are analyzed and reveals how wind directions affect the response of LNG tanks under wind load. The analysis of wind-induced response is carried out, adapting quasi-steady assumption and Davenport spectrum. The results show that under along-wind fluctuating wind load, the changing trend of deformation and stress is close to the result under static wind but the extreme response is twice. Compared to the response under other static loads, static wind load and along-wind fluctuating wind load have little influence on LNG tanks.

Abstract:To obtain the response rules of typical super high-rise building during the whole construction process, based on Shenzhen Kingkey Financial Center, the construction monitoring system was established and improved to keep tracking the whole process of construction. Response data of the construction process was attained to verify system availability. Furthermore, the tracking simulation of full-process construction was conducted using the developed super high-rise construction simulation technology, and the law of accumulation of vertical deformation and development of stress was studied by integrating simulation data and monitoring data on Shenzhen Kingkey Financial Center during full-process construction. The results indicate that vertical compressive deformation of the structure and stress of critical vertical elements grow steadily with the progress of construction schedule, without large mutation, overall stress of components of structure is small and has much redundancy, which proved that construction plan and schedule of Shenzhen Kingkey Financial Center was reasonable. Final simulation results agreed well with the measured results certified to practicability and accuracy of full-process simulation and monitoring technology, which can be applied in the following of whole process of similar super high-rise structure and guide the construction process.

Abstract:In order to ensure the structural safety of plate-fin heat exchanger, a model was proposed to simulate the stress of plate-fin structures in the cool-down process. The stress of plate-fin structures was investigated in the cool-down process based on directly coupled Finite Element Method. The results showed that the most easily damaged area happened in the brazed joint between fin and plate in the cool-down process. At the same time, the stress was obviously influenced by the temperature difference between natural gas (NG) and mixture refrigerant (MR) and increased with increasing temperature difference. The heat transfer performance had little influence on the stress of plate-fin structures when the temperature difference between NG and MR was less than 10 K. The stress of plate-fin structures was also slightly impacted by the temperature drop rate as the temperature drop rate of NG was the same as that of MR in the cool-down process.

Abstract:To insure the construction and running of slurries transportation pipeline be economical, the annualized conversion total cost model of slurries transportation pipeline was set up. Considering the impact of slurries concentration and slurries convey velocity on total cost of slurries transportation pipeline, these two parameters were chosen to be variables for optimizing. In view of the complex nonlinear of the model, the parallel global search ability of combined GA-DE (genetic algorithm-differential evolution) algorithm was utilized to optimize the design parameters of slurries transportation pipeline, the result of which was proved effective. Then this method was applied to a sludge treatment plant for final disposal in Changchun City. The optimization results showed that the optimum slurries concentration was 2.32％, the transportation velocity was 1.10 m／s, the diameter of the pipeline was 300 mm, and the annualized conversion total cost was 528.3 thousand Yuan RMB under the condition of flow rate of 0.226-0.045 m³／s (slurries concentration varying from 0.8％ to 4.0％) and the transportation distance of 4.5 kilometers.

Abstract:At present, study on the theory of quantify leakage is few internationally, and the establishment of water supply network leakage model is used more for estimating microscopic model but not used for calculation of whole physical leakage in water supply network. This paper modeled leakage of different consumers, different characteristics of leakage by water supply network leakage experimental platform. The theory of blind source separation was applied to leakage separation, and the data obtained from on-line monitor system was processed by fast independent component algorithm to get leakage separation. This provides powerful basis for taking measures of water supply network management, reduces leakage and improves level of controlling leakage.

Abstract:Field-flow fractionation, hold great promises as a branch of chromatography to improve separation of macromolecules, particles and colloids ranging from 1 nm up to100 μm. This paper presents the concept, theory and varieties of field-flow fractionation, including thermal field-flow fractionation, sedimentation field-flow fractionation and electrical field-flow fractionation, and also gives a better understanding of how to utilize these technologies as well as to provide appropriate technical solutions to environmental issues. Our argument also raises the bottleneck in miniaturization and commercialization of filed-flow fractionation. Furthermore, field flow fractionation, couple with many analytical techniques, can be adapted to a wide range of applications. With the development of integration techniques in acoustics, optics and magnetics, a portable field-flow fractionation instrument which serves the environmental monitoring will come true.

Abstract:To obtain the optimal process parameters, the orthogonal test and response surface methodology coupled with central composite design were applied in the optimization of electro-Fenton process as advanced treatment of coal chemical industry wastewater, and a quadratic model was developed to predict the treatment performance. The results showed that the factors affecting TOC removal in descending order was pH, current density and Fe2+ concentration according to the orthogonal test. The developed quadratic model could predict the response accurately, and the optimal parameters were determined as pH 4.3,1.56 mmol／L of Fe2+ and 14.74 mA／cm² of current density, with the predicted optimal TOC removal efficiency of 61.58％. The electro-Fenton could serve as a effective technology for the advanced treatment of coal chemical industry wastewater.

Abstract:Cornstalks, as a kind of cheap substrates, can effectively reduce the cost of bioflocculant’s synthesis. With 1.7％ of dilute sulphuric acid hydrolyzing cornstalks, the hydrolysate containing pentose-xylose and hexose-glucose can be produced. Pentose is difficult to be metabolized by microorganism; obtaining strains which metabolize pentose and hexose synchronously from cornstalks are the key to converse of bioflocculant. This study, based on cornstalks hydrolysate as substrate in screening flocculation Strain W4, explored its ability of synchronous metabolism pentose and hexose. The results revealed that Strain W4 was identified as Bacills subtilis via 16S rDNA. The metabolic rate of glucose (0.27 g·L-1·h-1) by Bacills subtilis exceeded the rate of metabolism of xylose (0.14 g·L-1·h-1), indicating Strain W4 can produce synchronous metabolism of xylose and glucose. The flocculation rate in synthesizing bioflocculant of Strain W4 from xylose and glucose mediums were 96％ and 97％ respectively. The main components of bioflocculant W4 were polysaccharide and protein through the analysis of FTIR (Fourier transform infrared spectroscopy).

Abstract:The phycoerythrin (R-PE) is a fluorescent protein, which has great commercial and industrial value. In order to obtain a high purity R-PE which above the food grade standard, the R-PE was separated and purified from the Porphyra haitanensis using aqueous two-phase system (ATPS). At the optimal conditions of polyethylene glycol (PEG) of 1500 in the ATPS (potassium sodium tartrate/PEG), pH of 8.06, the tie-line length (LTL) of 22.30% and volume ratio (V_r) of 0.12, purity of the isolated R-PE would increase from 0.43 (initial purity) to 1.47 after the first extraction, with a recovery rate of 84.42%. After the second ATPS extraction, achieved a purity and purification factor of 1.55 and 3.60, respectively. The isolated R-PE had a high biological activity. It was a successful purification process for R-PE for industrial application, with the advantages of high efficient and low cost.

Abstract:In orderto have a better understanding of the relationship between residential development and urban thermal environment, three typical residential districts in the downtown area of Shenzhen including high-density city village, multi-storey residential district and high-rise residential district were investigated in this study.The characteristics of land surface temperature (LST) in residential district and its relationship to the parameters of residential development were also quantitatively analyzed using Landsat5 TM and construction census data. The results showed that the heat island effects were observed in these residential districts.The average heat island intensities for high-density city village, multi-storey residential district and high-rise residential district were 3.53 ℃, 2.62 ℃ and 1.60 ℃, respectively. The LST in residential districts was positively correlated with building density, but negatively correlated with surface humidity, vegetation coverage, building average height, building mean nearest neighbor distance and plot ratio. Additionally, the multiple linear stepwise regression analysis indicated that surface humidity and building average height were the major factors for the variations of LST in the residential districts. Au these results will provide valuable information for the quantitative evaluation and optimization of thermal environment in urban residential districts.

Abstract:In order to provide recommendations for the use and design of street space under the perspective of microclimate thermal comfort. The study, taking transitional seasons (spring and autumn) of winter city as microclimatic background and urban residential streets of Harbin for example, determines the main climatic factors and spatial pattern factors which bring big difference to microclimate thermal environment of urban residential streets in winter city. With real-time measured data testing the accuracy of simulation data as the premise, applying microclimate thermal comfort zoning method, the research conducts a preliminary analysis for relevance between microclimate thermal comfort and spatial patterns of residential streets in winter city, and on this basis proposes the corresponding optimization strategies of spatial patterns in residential streets of winter city.

Abstract:In order to meet the need of concrete-filled double skin composite shear walls in construction, quasi-static testing of two concrete-filled double skin composite shear walls have been carried out, and analysis of their load bearing properties and seismic performance has been completed. The results show that the composite shear wall can give full play to both materials and is an anti-shear member with superior performance. Although opening reduces shear wall’s bearing capacity and initial stiffness, it has good influence on the shear wall’s deformation capacity and energy dissipation capacity. A large amount of numerical models have been established to analyze the influence of opening configuration parameters on the composite shear wall’s seismic behavior, including the position, the shape and the size of the opening. Based on the finite element analysis, formula for calculating the reduction coefficient of bearing capacity has been proposed, and the structure requirement of opening has been suggested and verified.

Abstract:To investigate the behavior of laterally loaded corrosion damaged reinforced concrete (RC) pipe pile, the governing equation of chloride diffusion into RC pipe pile was established based on Fick’s second law. Considering initial and boundary conditions, the analytical solution of chloride diffusion equation was presented. The critical corrosion penetration of reinforcing steel corresponding to cracking of concrete cover occurs was presented based on thick-walled cylinder model. Based on Faraday’s law, the time for corrosion-induced cover cracking in RC pipe pile was estimated. Then the attenuation law of flexural stiffness of corrosion damaged RC pipe pile exposed to marine environments was investigated by introducing the reduction factor of flexural stiffness. The time-dependent behavior of laterally loaded corrosion damaged RC pipe piles exposed to marine environments was further analyzed. The analysis results show that the chloride-induced reinforcement corrosion had a significant effect on the behavior of laterally loaded RC pipe piles exposed to marine environments. The flexural stiffness of RC pipe pile decreased nonlinearly with the increase of exposure time. The maximum negative shear force and the lateral deflection increased with the increase of exposure time, while the bending moment decreased.

Abstract:To understand the performance of buckling-restrained brace (BRB) as a lateral-force resisting component, an assembled all-steel double-core BRB was designed, and its bearing and energy dissipation capacities was studied through quasi-static experiments. Firstly, a single-core BRB specimen was tested to find any design and anchorage deficiencies, and after improvement, the load-displacement curves and low-cycle fatigue curves were successfully obtained for other single- or double-core specimens, and the design parameters of the BRBs, such as strength, deformation, and energy dissipation, etc., were obtained after studying the characteristics and laws of the curves. Furthermore, numerical simulations were conducted on BRBs using Bouc-Wen model under earthquake excitations. The test and analysis results show that BRBs overcome the deficiencies of the traditional braces which tend to buckle under compression. The hysteretic curves are basically symmetric for compression and tension, in full spindle shape, with high damping ratios, and endure fatigue well under reciprocal loads. The hysteretic properties can be simulated well by Bouc-Wen model. The proposed double core steel BRBs have stable performance and are east to assemble, and are suitable for practical engineering application.

Abstract:To reduce the emission of the strong greenhouse gas nitrous oxide (N₂O) in partial nitritation system, a lab-scale SBR treating synthetic high-ammonium wastewater (around 600 mg·L-1 of influent ammonia) was investigated for the effect of pH values (7.5,8.0 and 8.5) on N₂O emission. The results showed that, the N₂O emission was observed under different pH values, and the total amount of N₂O emission decreased with pH value increment. At pH 7.5,8.0 and 8.5, the N₂O emission amount accounted for 3.81％, 2.35％ and 2.00％ of the influent ammonium nitrogen, respectively. At pH 7.5, in the initial 50 min the N₂O emission rate firstly increased (maximum value of 44.5 μg·min-1·g-1) and then returned around 26.4 μg·min-1·g-1. At pH 8.0 and 8.5,3.7 and 22.9 μg·min-1·g-1 of maximum N₂O emission rate were achieved in the initial 50 min, respectively, however, they increased slowly with the pH decrease and nitrite accumulation.

Abstract:Oleaginous microalgae can produce biodiesel by solar energy, transforming the inorganic carbon into organic carbon. However, the reduction of the energy consumption in the process of oleaginous microalgae cultivation is the bottleneck to achieve large-scale production of biodiesel. By the optimization of the Chlorella sp. cultivation in an airlift photobioreactor, as well as the energy calculation and comparison of different culture conditions, the work proposed that, the adoption of optical fibers as the internal illumination source and a proper flow rate (0.6 L／min) in the cultivation of Chlorella sp. in the airlift photobioreactor could enhance the energy efficiency and obtain the maximal productivity per energy consumption 4.40 g／(W·d), 8-25 folds of those with the external illumination conditions.

Abstract:To study the inherent law of bonding defects and mechanical properties between steel and cement-based materials, considering parameters of the form of rebar surface, the initial bonding defect level, the relationship between ultrasonic parameters and the initial defect was established by ultrasonic detection technology. Furthermore, static pull-out test were carried out to get the relationship between pullout force and factors including anchoring interface, steel surface. Three-dimensional finite element program ANSYS were used to conduct numerical simulation. The theoretical analysis results were compared with the experimental results. The results indicate that the results of theoretical analysis and the result has good agreement.

Abstract:To obtain the cable force under dead load, the data was recorded during the closure of bridge by the health monitoring system of an existing bridge. Firstly, the linear relationship was obtained between the cable force and temperature through correlation analysis, and the results were verified by simulation results of finite element model. Secondly, the temperature sensitivity of the different cable force was analyzed using the finite element model. The stay cables deeply affected by the temperature include the short cables on both sides of the tower, longer cables near the assist pier of side span and long cables of the mid-span. Finally, nine years' monitoring data were selected and assessed based on correlation of slope coefficient and variable weight synthesis principle. The results show that the cable force assessment model effectively reflects the uniform change and non-uniform change of cable forces.

Abstract:The influence of rubber particles on recycled aggregate concrete durability was studied in this paper. Compressive strength, permeability, and frost resistance were carried out to investigate the effect of rubber particles with different size of 60 mesh, 1-3 mm and 3-6 mm and replacement content replacing fine aggregate of 10 kg／m³,0 kg／m³ and 30 kg／m³ on recycled aggregate concrete. The results show that the compressive strength of recycled aggregate concrete is reduced with the addition of rubber particle, and the compressive strength is decreased with the addition of particles replacement content and particles size. The permeability and frost resistance of recycled aggregate concrete is improved by the addition of rubber particle and is raised with the increase of particles replacement content and decrease of particles size, and the recycled aggregate concrete expressed the best durability performance with rubber particles of 60 mesh and replacement content of 30 kg／m³.

Abstract:For the improvement of the water quality and eco-balance in the area of Jianghan hydropower station, the treatment of water-fall wetland to the combined sewer overflow pollution was investigated. The comparison with ordinary wetland illustrated the higher removal rates for COD, ammonia, total nitrogen, total phosphorous of the water-fall wetland, with the percentage of 13.1％, 7.9％, 6.1％ and 6.0％,respectively. The water-fall wetland embraced more appropriate gradient of dissolved oxygen, while the end of the ordinary wetland turned easily to be anaerobic. The Biolog Ecoplate confirmed the higher microbial utilization of carbohydrate and its derivatives, amino acids and its derivatives, fatty acid, lipid, metabolic intermediate and secondary metabolites in the water-fall wetland. PCR-DGGE analysis presented more diversified microbial structures in the water-fall wetland, and in which the dominant species were highly related with the removal of the pollutants.

Abstract:In oder to solve extremely unstable link quality and communication failure caused by strong electromagnetic noise and interference in special coal mine environment, this paper proposes an Experience-Weighted Attraction(EWA) selection algorithm. Based on the system structure analysis in depth, it establishes more detailed and reasonable multi-layer reward feedback system. Research is conducted by the method of simple repeated probability experiments through software simulations. By comparing with traditional fixed single channel transmission and Q learning, channel selection strategy with EWA learning has more advantageous performance on sensitivity and stability.

Abstract:In order to analyze the error source of seismic parameters of PSD model and its sensitivity influence on ground varying motions and seismic response of long-span Bridge, two methods (direct and integral method)that usually used to solve the parameters in target PSD model according to CRS are briefly reviewed. Then, a visualization program named TJU.SPSP was developed and the main parameter values of PSD were listed in fixed format. Base on the results, the fundamental error source that caused by different methods were analyzed obviously. Moreover, the program for multi-point earthquake motions simulation (MEMS_b) was updated and the relationship between earthquake-induced ground motion energy and site soil type were summarized. The results indicate that the two methods have significant influence on the amplitude and band width of dominant frequency. The parameters describing the low-frequency component in PSD models are important and can't be ignored. Furthermore, the physical and mathematical significance of damping ratio in PSD models were clarified. Finally the validity of the theoretical analysis was verified by analyzing the seismic responses of a real long-span bridge.