Abstract:To improve the accuracy of aerodynamic parameters of membrane structures depending on numerical simulation method, the aerodynamic characteristic of ETFE air-inflated membrane structure on the roof of the National Aquatics Center (NAC) is analyzed based on the hybrid substructure method of on-site monitoring and CFD numerical simulation in this paper. The ETFE air-inflated membrane structure and flow field are considered as two substructures, the vibration response of the ETFE air-inflated membrane structure is measured from the Health Monitoring System of NAC and treated as the moving boundary condition of air-inflated membrane structure in the flow field. Only the flow field around the moving boundary is simulated by the CFD code CFX 11.0. By CFD numerical simulation, the additional mass, aerodynamic damping and aerodynamic force of ETFE are obtained and the changing laws of these aerodynamic parameters with time and wind speed are studied. The research results indicate that the hybrid substructure method of on-site monitoring and CFD numerical simulation is an effective approach to obtain aerodynamic characteristics of air-inflated membrane structure.[JP]

Abstract:To research the shear-compression behavior of mortar-less masonry which has potential in the reinforcement concrete frame and masonry structures, 36 shear-compression tests were carried under cyclic loads. During the test, the influence of cyclic shear-compress load on the behavior was emphasized. After that, a finite element model was built with interface and plain stress elements. The research indicates that the coulomb friction law is adequate to represent the failure of mortar-less joints under moderate stress levels, the friction coefficient varies under different load aptitude which can’t be ignored and the model with interface element and plane stress element is valid in simulation of shear-compression test.

Abstract:To investigate the static and dynamic mechanics properties of undisturbed silty clay sampled from the subgrade of Changchun-Siping highway, the consolidation undrained triaxial test and resonant column test were carried out under different confine pressures. Test results show that the properties of undisturbed silty clay are relate to the pre-consolidation condition. With the increasing of confine pressure, the static strength and the maximum elastic modulus increase. The relationship between maximum dynamic shear modulus, reference shear strain amplitude and confine pressure display a linear formulation. The confine pressure plays a little influence on the maximum damping ratio and the fitting parameters of damping ratio. Based on these, Duncan-Chang model parameters, maximum dynamic shear modulus and reference shear strain amplitude with the confine pressure were quantified.

Abstract:To reduce the energy consumption and solve the problems of serious leakage, frequent bursting of pipes and uneven pressure distribution in water distribution system of mountainous urban, a model for dividing districts and optimization is built. Based on systematized study of water distribution system of mountainous urban, a two-step method is proposed for optimizing the built water distribution system. In the first step, the built network is districted by the algorithm proposed in this paper; in the second step, every sub-district is optimized by NSGA-Ⅱ. In district algorithm, the elevation difference value between two nodes is taken as the characteristic value of corresponding pipe in pipe network. Whether a node in a pipe is classified as one sub-district depends on that the characteristic values between the node and other nodes in this sub-district is within a given maximum allowable elevation difference. The optimization of pipe diameter in every sub-district is solved by NSGA-Ⅱ, which has been successfully used in many multi-objective cases. In the process of evolution, the direction of mutation is that the diameter of every pipe approximates its economic pipe diameter. A practical dividing district and optimization of water distribution system is made by concerned calculation programs. And the results show that the energy consumption is reduced greatly and the pressure distribution of water distribution system is more even by proposed method.

Abstract:To make sure of surge protection scheme of water supply pipeline with long distance and huge terrain variation, this paper builts up a surge protection model and obtains the solution of the model by method of characteristics. Surge tank, one way surge tank and vacuum breaker were used as negative pressure protection equipment, then the optimal surge protection scheme was determined based on the simulated result of surge protection effects under the condition of pump trip. The results showed that when the air valve and vacuum breaker valve were installed together on the peak of the pipeline, the effect of surge protection is the best.

Abstract:In this paper, magnetic Fe/Mn nanocomposites were synthesized for the removal of Pb2+ from solution. The adsorption capacity and the influence factors such as pH and temperature were analyzed. The results showed that the maximum adsorption capacity (Q₀) of the sorbents towards Pb2+was 118.06 mg/L according to the Langmuir isotherms (298 K). The Pb2+ removal capacity of the adsorbents increased with the increase of pH (1.5-5) and temperature (303-323 K). In addition, the kinetic adsorption could be fitted by the pseudo-second-order model equation. At last, the thermodynamics of Pb2+ was studied at various temperature and the thermodynamic parameters were given which confirmed that the adsorption was endothermic reaction.

Abstract:Microbial culture-independent technology, such as DNA fingerprinting technology, pyrosequencing, molecular hybridization technology, metagenomics, metatranscriptomics, metaproteomics, metabolomics and so on, has developed rapidly and been applied extensively in many fields, which could assist in the identification of microbial species from natural or anthropogenic environment rapidly and accurately. The microbial culture-independent technology has provided crucial in-sights for revealing microbial community structures, functions and remediation mechanism during bioremediation process and improving the detection efficiency of bioremediation. This review is mainly focused on the advanced applications of molecular biology and microbial culture-independent technology of “-omics” in gauging microbial community structures, functions and dynamics at contaminated areas.

Abstract:To control agricultural non-point source pollution, the cleaning biological fertilizer and chemical fertilizer were used together to raise nitrogen use efficiency. The growth and production of rice under the conditions of single application of nitrogen fertilizer(N), single application of biological fertilizer with Glomus mosseae as the subject(M) and joint application of nitrogen fertilizer and biological fertilizer(NM) were studied, and the results reveal: (1)The application of nitrogen and G.mosseae(NM) makes rice reach the highest net photosynthetic rate, and increases by 4.5％ and 5.0％ more than N and M treatment, respectively. (2) The nitrogen fertilizer can increase the aboveground biomass by 22.8％, the biological fertilizer can increase the underground biomass by 41.5％ significantly (P＜0.05), and NM treatment can promote both the above-and under-ground biomass (37.0％ and 35.0％, respectively). (3) The NM treatment increases rice yield by 4.8％ more than traditional nitrogen fertilizer management. Therefore, mycorrhizal infection to the rice can effectively improve the efficiency of resource utilization, growing and producting capacity.

Abstract:To increase the dissolution ratio of waste activated sludge (WAS), which contributes to the post bio-treatment, the thermal alkaline pretreatment was applied and the optimization of operational parameters for enhanced acidification performance of WAS by thermal alkaline pretreatment was studied using response surface methodology. Mesophilic anaerobic fermentation experiment of pretreated WAS was conducted. Experimental results showed that temperature, pH and treatment time had significant influence on lysis rate of WAS and the maximum lysis rate of 48.10％ was predicted when the operational parameters were temperature 88.83 ℃, pH 12.0 and treatment time 73.79 min, respectively. After thermal alkaline pretreatment, the lysis rate, solute protein and carbohydrate concentrations were all apparently higher than those of untreated sludge (blank test). The maximum amount of volatile fatty acids (VFAs) was 3 269.20 mg/L in the thermal alkaline pretreated test on day 3, which was 3.22-fold of that in the blank test. VFAs composition analysis revealed that acetic acid was consistently most abundant, followed by n-butyric acid and iso-valeric acid in the pretreated test, while the order was changed to n-butyric acid> acetic acid> propionic acid in the blank test.

Abstract:To analyze the impact of season on human thermal adaptability and the influence of cold radiation from window in winter on human local thermal sensation, a field study on indoor thermal environment, thermal sensation and thermal comfort in classrooms at a university in Harbin during the heating period in winter and spring was conducted. The environment parameters were tested and at the same time the subjects’ thermal sensation were undertaken. The results show that the neutral temperature is close to the indoor average temperature during winter. The neutral temperature is obviously lower than the indoor average temperatures during spring. In warmer climates, the subjects felt warmer in winter than that in spring. This shows that people in Harbin has fully adapted to the indoor and outdoor thermal environment in long-term cold winter. If the indoor air temperatures are kept too high in winter, people will feel more uncomfortable. The human adaptability to thermal environment should be made full use of by reducing the indoor temperature during winter and spring to improve comfort and save energy for heating. The subjects nearby the window feel colder than the control group subjects. The occupants often feel cold at their shoulder and back, and feel comfortable at their head. The adaptive measures taken by the subjects include opening doors or windows, increasing or decreasing clothes, etc.[JP]

Abstract:Transport route optimization of dangerous goods makes lower transportation risk and cost of the enterprise, meanwhile it provides basis reference for the government decision. On the basis of urban master planning, the characteristics of transport of dangerous goods was analyzed, and then the index system on transport of dangerous goods was established. In order to implement this research and quantify the indicators, road characteristics and nature of land along the section has been used to evaluate the risk, simultaneously, the emergency response capacity was considered as the correction factor to improve the risk model, and the BPR impedance function was applied to calculate the transportation costs, then the calculation process of transportation risk and costs was given with an example of Pingxiang, Jiangxi. On this basis, a bi-objective optimization model was created with the target of risk and cost, and method of solving the model was discussed. This model provides a theoretical basis for the transport network of dangerous goods planning and design for its simplicity, practicality and operability.

Abstract:To determine the time of green light for pedestrians at signalized intersection with exclusive pedestrian phase, a model for estimating crossing times is proposed. The model consists of two parts. The time function for pedestrian crossing refuges is derived using wave theory, and the time function for pedestrian crossing intersection diagonally is an adaptation of existing HCM model. The model attempts to describe the influence of dominant platoon, opposite platoon and rectangular cross pedestrian flow. According to the data extracted from video survey and artificial measurement of four intersections at Weihai, the statistical analysis comes to conclusions. The 15th percentile speed of pedestrians crossing intersection diagonally and non-physical refuges is 1.43 m/s, and that of pedestrians crossing physical refuges is 1.35 m/s. The effective widths of pedestrians crossing intersection diagonally are 9 meters and 12 meters. Finally, the model parameters were calibrated by using SPSS. Results of a case study show that the model can more accurately predict pedestrian crossing time, and the error is within 5％.

Abstract:For the better use of metamaterials, the surface waves of metamaterials are studied in half-space model with dipole radiation source. Using the Sommerfeld integrals of TM wave and TE wave, the branch-cut’s effect on the computation of the integrals is investigated based on saddle point algorithm. The distribution and validity of pole points for the integrands is analyzed according to the properties of complex integral. For TM wave, there are lateral wave and Zenneck surface wave in the case of taking left-handed material as substrate; for TE wave, no Zenneck surface wave can exist in any case of metamaterials.[JP]

Abstract:To analyze the corrosive inhibition effects of BTA in phosphoric slurry for copper electrochemical mechanical polishing(ECMP), the electrochemical behavior of copper in 30％ H₃PO₄ electrolyte with 0.01 mol/L benzotriazole (BTA) as an inhibitor was studied. The potentiodynamic polarization curves and the potentiostatic etching at different anodic potential of copper in the electrolyte were measured. The morphologies of the corroded workpieces were observed and the forming process of CuBTA surface film was analyzed by AFM and XPS. The results show that the surface roughness increases first with the dissolution of copper at a definite anodic potential range, then stabilizes at certain lower value owing to the dissolution inhibition effect of the Cu-BTA layer formed by adsorption of copper ions to BTA molecules. The anodic potential applied on copper should be kept below 0.5 V to sustain CuBTA film-formation, which takes near 2 min to stabilize at the test conditions.

Abstract:There are 6 methods, pyrolysis, high-salt low-pH, isopropyl alcohol, CTAB, SDS or GuSCN, used in the extraction of milk powder genomic DNA for the molecular marker analysis of high quality and sufficient samples. To find out the better method of them, the effects of different methods were compared by detecting the DNA by optical density, agarosegel electrophoresis and polymerase chain reaction (PCR). The results showed that the genomic DNA extracted by all methods except for isopropyl alcohol and SDS method could be used in PCR reaction. Meanwhile, the better DNA concentration and purity could be gained by different methods in the order of pyrolysis, GuSCN, High-salt low-pH, CTAB. These methods are simply to operate, fast to gain results, and suitable for the extraction of total DNA from milk powder.

Abstract:With the application of suspension bridges with double main spans, the aerostatic stability should be studied in order to maintain the safe operation. A procedure based on aerostatic load increment and double iterations was programmed and applied to analyze the aerostatic stability of three suspension bridges with double main spans. The characters of aerostatic instability for suspension bridge with double main spans were gained by comparing the instability modes between the suspension bridges with single and double main spans. There are two aerostatic instability modes for suspension bridge with double main spans, which include bilateral anti-symmetric instability mode and unilateral non-symmetric instability mode. Meanwhile, the mechanism of the two modes was discussed in detail.

Abstract:To predict the buffeting internal forces of bridge components under complex incoming wind, the linear transformation relations between internal force of bridge components and their deformation were discussed in probability and statistics terms. The present paper deduced the multiple linear regressive model between the internal force and its deformation. Verification analysis is also performed to make sure that the regressive model is of great significance and can be applied in the engineering. Using the regressive model, the internal forces induced by buffeting under complicated incoming wind are predicted. This methodology can directly transform the buffeting displacement of bridge under skew wind achieved from wind tunnel test into internal force of bridge components, without using the complex theory of buffeting analysis under skew wind.

Abstract:To search the influence of initial strain induced in production and service period on HDPE sheath, an artificial photo-aging test and a tensile test were designed. A kind of iron fixture was devised to produce initial strain on HDPE test pieces. The aging tests were conducted on test pieces with and without initial strain in artificial photo-aging test chamber. The tensile tests were undertaken on specimens cut and processed from test pieces after aging test. Comparisons and analysis were made on tensile properties of the specimens. The results show that no obvious aging phenomenon exists in the specimens, it is not appropriate to conclude that the initial strain is the main cause of sheath crack. It is suggested that the test method should be improved.

Abstract:To investigate the stress variation of reinforcement in beam under fatigue loads, in this paper, based on fatigue test results of 12 post-tensioned partially prestressed concrete beams, the changes of reinforced maximum, stress amplitude which are closely related with the fatigue failure of partially prestressed concrete beams are obtained. The experimental results suggest that the prestressed and non-prestressed reinforced are basically at the same ratio of development. It has been found that the key factors of affecting fatigue capability of partially prestressed concrete beams are stress amplitude of reinforcement. The bond degradation of reinforcement and reduction of effective prestressed stress lead to stress redistribution, which are the two main important reasons why prestressed and non-prestressed reinforced damages are not in desynchronized way with the increase of repeated loading. Finally, a calculation method of prestressed steel stress increment in a cracked section after decompression is proposed by the experimental analysis, and the calculation results are matched with the test results quite well.[JP]

Abstract:To study the choice behavior of travelers’ departure time under urban dynamic road traffic information, this paper designs stated preference survey to obtain data from travelers with driving experience in Dalian city and develops a time choice behavioral model based on discrete choice method. The analysis results over this model indicate that the parameters of maximum travel time and minimum travel time are very different, and the estimated coefficients are-0.065 7 and-0.027 9 respectively. The most sensitive parameter is travel cost. The female’s sensitivity to the uncertainty of travel time is higher than male’s, and the travelers’ age, income and years of driving experience significantly impact their departure time choice behavior, which will provide decision basis for personalized traffic information service.

Abstract:The theory model of current RC section non-linear analysis is studied to clarify the data demand, algorithm characteristics and data processing pattern. Parametric object-oriented modeling method is adopted to express the data demand of RC section non-linear analysis and the corresponding building information model (BIM) is developed. The BIM is used to fit the constitutive relationship of concrete according to environmental condition, loads and internal factors. Furthermore, Non-Linear Analysis System is developed based on the BIM to automate the analyzing process of deterioration laws of RC section under conditions of environment, loads and internal acts. A case study is elaborated to demonstrate how the system is capable of conducting the RC section non-linear analysis and the results fit well with the data from detection on spot.

Abstract:To obtain calculation formula of lateral load distribution for multi-box steel-concrete composite girder bridges, the traditional rigid transverse beam method, modified rigid transverse beam method and rigid connected beam method are modified for the multi-box composite girder bridges by considering the interface slippage’s effect. The results obtained by the modified theoretical algorithms are compared with the values gained by finite element method which has been validated by experiments. The results show that the modified rigid connected beam method considering slippage effect is applicable to calculate the lateral load distribution of mid-span cross section in multi-box composite girder bridge. When the bridges meet the narrow bridge conditions, i.e. the bridges with span-width ratio is not less than 2, the modified and simplified rigid transverse beam method considering slippage effect is also suitable to calculate the lateral load distribution of the mid-span in the bridges. Finally, it is suggested that the partial load effect of the bridge could be reduced by using incomplete shear connection form or properly strengthening the transverse connection rigidity among steel box girders when the multi-box composite girder bridges are designed.

Abstract:To accurately evaluate the bearing capacity of pavement structures, this paper proposed a upper shakedown analysis method based on the kinematic shakedown theorem, then calculated and analyzed the dependence of dimensionless upper shakedown load on the loading distribution, depth and angle of internal friction in the basecourse and ratio of elastic module in the basecourse and subgrade. Meanwhile the upper shakedown load was compared with elastic limit, plastic limit and lower shakedown load. The results showed that the upper shakedown load decreases with the increasing of a/r in a single-heel system, while increases in a dual-wheel system. The upper shakedown load increases with the increasing of depth of basecourse/subgrade interface and angle of internal friction in the basecourse, and the growth is slow as the value h/r (the ratio of surface course thickness to load equivalent radius)is greater than 2.5. The upper shakedown load decreases with the increasing ratio of E/E₀, and the upper shakedown load is the maximum when E/E₀ s 1.0. The upper shakedown load is greater than elastic limit and lower shakedown load, lesser than plastic limit. Our researches show that the shakedown limit based on the upper bound theorem can accurately represent the bearing capacity of pavement structures and could be a new reference to the analysis and design of pavement.

Abstract:To alleviate the traffic congestion in major urbam cities in China, the regulation of parking demand and parking price is given in central areas during peak hours. Based on the implementation of the regulation at Beijing downtown area, a multi-modal travel survey was carried out and a bi-level programming model for adjesting the government-designated parking fares and the cheaper and convenient way for residents to travel is set up. The numerical calculation provide a proper relationship between the parking price and the use of parking facilities and commuter vehicles. The parking pricing policies can effectively alleviate the commuter traffic congestion at central area and provide references to other cities.

Abstract:According to the fact that the linear imaging model cannot explain the lens distortion,and to overcome the problem that the ordinary calibration methods are not suit for the change of height and angle, based on the pin-hole model and the previous distortion correction, this paper builds up a mirror coordinates system to study the reflection relation of pixel and angle. By using trigonometric functions and distortion coefficient,the height parameter and angle parameter are introduced into the model,and then the non-linear model is obtained. Finally, under different kinds of situation, comparing with Tsai’s method, the algorithm validity is verified. After changing the camera angle and height, the algorithm, which does not require re-calibration, is still with good accuracy and robustness. Thus, the algorithm can be applied to the engineering field.

Abstract:To provide a theoretical and technical basis for base isolation of LNG storage tanks, based on the shear beam theory for the outer-concrete-tank and the velocity potential theory for the inner-steel tank, and by introducing isolation stiffness and damping, the equivalent mechanical model of LNG storage tank base isolation system was established, the movement equations of LNG storage tank base isolation system were derived according to Hamilton's principle and the theoretical expression of seismic response were given. To 160 000 m³ large LNG storage tank, the numerical analysis results showed that, in addition to wave height, the base shear and overturning moment damping effect was obvious, the foundation design of LNG storage tank was necessary to consider the impact of outer-tank, however, when designing the inner-steel tanks, the impact of outer-tank could be ignored. It was necessary to optimize the design considering the influence of isolation on the sloshing of base isolation of LNG storage tanks.

Abstract:To make the Bauhinia Park View Tower in Changzhou-the special ring-shape Ferris wheel construct successfully, the paper researched the installation and process control method which was based on the theory of process control. The cantilevered symmetrical installation method was adopted and the process control scheme was implemented by prestressing the structure, with the help of masts and cables and other auxiliary facilities. The main principle of the process control was to control the whole shape after construction. Besides, the structure internal force was controlled. In addition, the efficiency of process control must be higher. The process control scheme was devised, and then the secondary development technology based on ANSYS was applied to iterative calculate the cables tension. By time-varying simulating and analysis, it indicated that the deformation after construction met the controlled demand. The internal force during installation and after construction met the demand of bearing capacity.