Abstract:To provide reliable verification and guidance for experiments, numerical simulations of 17 high-strength aluminum alloy columns in compression were conducted using ABAQUS and the results were compared with experimental results. Factors which influenced simulation results, including meshes size, thickness of end plates, initial imperfection and material properties were analyzed. 3D full integration continuum element C3D20 and Ramberg-Osgood model for stress-strain relationship were adopted in simulation. The simulation results show that the relative errors of buckling load between experiments and simulations are under 12％; the meshes size and thickness of end plates have a negligible influence on stability coefficient, and the existence of end plates rarely influence mechanical properties of specimens with hinge supports; as initial geometric imperfection ascends and the parameter n of aluminum alloy descends, the value of stability coefficient decreases; buckling loads of specimens obviously increases as proof stress f_0.2increases, especially for specimens with small slenderness ratio.

Abstract:To master the aseismic ability of Shanghai 65m radio telescope structure, according to the information of site conditions, the safety properties of antenna structure in the initial design was analyzed under activities of frequent and rare earthquake by using time-history method when aseismic fortification intensity is Ⅶ. Subsequently mechanical responsive targets which are crucial to the structure under activities of frequent earthquake, frequent earthquake combined with static unitized load mode and infrequent earthquake were given. The results show that the weaknesses of the structure (plastic deform appears in some bars) are found under activities of frequent earthquake combined with static unitized load mode. Under activities of infrequent earthquake, artificial ground motion produces the most intensive effect on the structure. To every kind of different pitching angle model the antenna structure does not break down under the activities of 3 kinds of infrequent earthquake. After some modifications to the initial design, and choosing the most disadvantageous model(its pitching angle is 5°), the analysis results under activities of frequent earthquake show that all targets of all bars meet the corresponding requirements of specifications when aseismic fortification intensity is Ⅷ.

Abstract:This study compares the snow load provisions recommended in design codes used in China, USA, Canada and the EU. It shows that the basic snow load requirements in Chinese standard are too simplistic to cope with major factors that control the complex roof snow load patterns. The recommended critical roof slope in Chinese standard is the lowest among the considered four design codes. Furthermore, the recommended snow loads for the gable, arched and step roofs in Chinese standard differ from the other three design codes in terms of the snow load pattern. The comparison allowed us to suggest some preliminary modifications to snow load requirements in Chinese standard, although a detailed probability-based calibration is needed to confirm the recommended changes.

Abstract:To investigate the deformation performances of high-rise steel frame structures in the serviceability limit state, full-path analyses was carried out for 30-story frames using finite element method, in which the random distribution of initial geometric imperfections in structural system and its individual members were taken into account by Monte Carlo method, and the probability density functions of the structural deformations were gained in probability statistics terms. The results indicate that the effect of the random initial imperfections on the frame deformations is so small that it can be neglected in the advanced analysis. Moreover, since the deformations at top of columns obtained from the second-order analysis are much larger than those from the first-order analysis, the second-order deformations should be used to estimate whether they meet the requirements of the serviceability limit state in the advanced design. A deformation performance-based practical advanced design method is proposed accordingly.

Abstract:The reinforced gradient concrete beams consist of normal and high strength concrete, in which the compressed zone is made of high strength concrete, and the tensile one is made of normal strength concrete. Experiment on these simply supported beams with two-point loading was carried out, and the test results of strains and deflections of the beams under short-term load were verified and compared with those of nonlinear analysis. It revealed that the average strain at the outer fiber in the compressive zone increased linearly with the increase of external loading. Thus, the general coefficient of average compressive strain at the outer fiber was introduced, and its calculated equation was proposed. Based on the analysis of crack development and curvature of cross section, the calculation method on the immediate and long-term stiffness was proposed for the reinforced gradient concrete flexural member with rectangle section.

Abstract:A numerical model to simulate loading process of prestressed concrete(PC) continuous beams and slabs at elevated temperature is presented. It is considered that plane sections before bending remain plane after bending. Based on the thermal-mechanical coupling constitutive models of concrete, reinforcing and prestressing steels, the transient strain, creep strain in concrete at time t+1 could be calculated by the stress in concrete at the former step. The coupled constitutive model of concrete could be decoupled, and the reinforcing and prestressing steels were calculated by the same way. Therefore, the moment-curvature relationships of PC beams and slabs subjected to fire can be calculated. The moment of flexure, deflection and support displacement of the beams and slabs imposed by curvature and support reaction together was calculated respectively. The support reaction was calculated by the iteration method until the deflection compatibility equation at the support was satisfied, and the deflection of continuous beams and slabs could be obtained. The deflection of PC continuous beams and slabs subjected to fire calculated by the computer program is verified by correlative fire resistance experiments. Through these studies, it is shown that support and span restraint effect has significant influence on the fire resistance of PC continuous beams and slabs. The mid-span deflection in side spans is larger than that in inner spans.

Abstract:Jar tests were conducted to expose the kinetic law of triclosan oxidation by potassium permanganate in aquatic environment. The rate constant of the reaction was obtained, meanwhile, the factors influencing the value of K, such as potassium permanganate dosage, pH value and temperature, were investigated. The results showed that triclosan was rapidly oxidized by potassium permanganate in aqueous solution with different initial concentrations of potassium permanganate, and second-order reaction kinetics was observed between triclosan and potassium permanganate with second-order reaction rate constant K=0.331 6 mL·s^-1·mol^-1.The second-order reaction rate constant was influenced by pH values, and K reached its lowest and highest level at pH 5 and 7 respectively. The rate of oxidation increased with the temperature increasing, and the reaction activation energy Ea=32.35 kJ·mol^-1, which revealed that the oxidation reaction between triclosan and potassium permanganate was feasible under usual water treatment condition. Therefore, potassium permanganate is a feasible oxidant which can removal the triclosan quickly and efficiently.

Abstract:To test biomass of photosynthetic bacteria (PSB) in water, and to provide a way of PSB sewage reclamation, this paper adopted HPLC to analyze the concentration of CoQ₁₀and thus obtained the concentration of PSB in water. The results show that the chromatographic condition is as follows: The chromatographic column is SphherisorbC18 (10 cm×4.6 mm ID); methanol-absolute alcohol (9∶1) as mobile phase at a flow rate of 1 mL／min; column temperature 35 ℃; Wave Length of UV detector 275 nm; sample size 15 μL; column pressure 16.4 MPa. By extracting 5 h with acetone, volatilizing acetone completely and dissolving it with absolute alcohol, this method may obtain the maximum relative extraction of CoQ_10. The average recovery ratio of external reference method is 99.13％ and RSD 0.81％. The highest radiance-extraction is acetone extraction 5 h before evaporating completely and then solving in ethanol. The concentration of CoQ₁₀ in PSB in various cultural conditions and growing phases is quite stable. The impurities or microbes in wastewater do not affect the testing result. The concentration of PSB is (Y+37.487)／25.431 g·L^-1, Y is peak area(V·s). This method is simple and accurate, and can be used for quantitative analysis of PSB in water.

Abstract:For determining the pollution status of endocrine disrupting compounds(EDCs) in Songhua River, solid phase extraction (SPE) followed by GC-MS／Yeast Estrogen Screen(YES) assay were used to analyze the EDCs concentration at 11 sampling sites of Songhua River. The results indicated that total five estrogen ∑5ES[JB))] was in the range of 6.59-30.97 ng／L, the average value was 17.23 ng／L, and the water from Dalian river outfall had the highest ∑5ES. Estrogen (E₁) and 17β-estradiol (E₂), which were mainly from urban sewage and contributed most of all estrogen and their concentrations, were in the range of 1.54-6.34 and 1.86-20.78 ng／L, respectively; Nonylphenol (NP), octylphenol (OP) and bisphenol A (BPA) were detected in all the sampling sites, with the mean values of 512.8,4.1 and 52.8 ng／L, respectively, which were mainly from the domestic sewage and industrial wastewater; The estrogenicity of river water detected by YES was in the range of 0.50-26.16 ng／L, and the highest EEQ occurred at the Haxia sampling site. The EEQ at other sampling site was all below 3.60 ng／L, which was at the same pollution level with other river, but it also existed the potential problems of ecological security in Songhua River.

Abstract:To combine the real-time run-off information and digital analysis system of water distribution network, and realize the real-time simulation and dynamic analysis for water distribution network, an urban water distribution network real time simulation system based on OPC communication of SCADA system was built up in this paper. Using SCADA software for OPC communication, the real-time operation information for water distribution network was gained. The simulation model was driven by real time monitoring flow and pressure data to simulate water distribution, to display pressure results online and to alarm pressure. The abnormal operation scenario could be detected in real time. The simulation system solved the problem of data input and user interaction of traditional network model, and offered a new idea for the development of intelligence water network.

Abstract:Based on the eutrophication appeared in Chaohu Lake, we analyzed the relation between the multifactor coupling and chlorophyll-a (Chla) with monitor data from 2005 to 2009 in western lake, and by correlation analysis and stepwise multiple regression, we inferred the dominant factors of algal blooms and established the prediction model of Chla variation. The results indicated that seasonal trend of Chla concentration was greater in summer and lower in winter in western lake. The Chla biomass was influenced by multiple effects of environmental factors, in which the dominant ones were air temperature, water level and COD_Mn. Under multifactor coupling environment, meteorologic and hydrologic factors were most significant to algal blooms. These results might provide scientific foundations for prediction and control of harmful algal blooms in Chaohu Lake.

Abstract:This paper studied the physiological and biochemical characteristics of a new strain of photosynthetic bacteria isolated from soil in details, identified its belonging, and used it to treat artificial soybean wastewater and reclaim resources. Results showed that the strain belonged to Rhodopseudomonas sphaeroides, and was named Z08. For treating wastewater with COD of 8 000-12 000 mg·L^-1 under 26-28 ℃, the optimal dose of PSB was 160-400 mg·L^-1; COD removal reached 85％ after 72 h. Various oxygen-light conditions were examined, and the best one was found to be natural light-micro oxygen condition. Under this condition, COD removal reached 73.5％ and biomass reached 2 125 mg·L^-1 after 72 h treatment. The optimal condition of Z08 treating soybean wastewater was as follows: natural light and micro oxygen condition, Z08 dose of 160-400 mg·L^-1, and hydraulic retention time of 72 h.

Abstract:To establish an optimization method for UV systems, numerical models were developed based on UV intensity field, flow field and equivalent reduction dose (RED). The model was verified using bioassay on the condition of the UVT (80％-95％) and the flow rate (240-600 L／h) with an annular UV reactor. Results showed that the model predicted the disinfection efficiencies with good accuracy. RED from simulations and experiments under different conditions had a difference of 3％-12％. RED increased with the increase of flow rate and decrease of the transmittance. However, transmittance had merely a slight impact, about 3％ on RED of high flow (600 L／h). Visualization images showed that near the inlet of the reactor, the UV intensity was weak while the velocity was large adjacent to the wall, which had a negative effect on disinfection efficiency. This numerical model provided a basis for UV system optimization and dose synchronization.

Abstract:To improve the treatment efficiency of a gas-water alternate membrane bioreactor (AMBR) and make full use of the membrane module, the efficiency of membrane surface loading on synthetic municipal wastewater treatment by the AMBR was investigated through a lab-scale experiment. The results showed that: the maximum COD, NH₄+-N and TN removal load by AMBR were 84.9,6.75 and 6.5 g／(m²·d) under the condition of intra-membrane oxygen pressure lower than 200 kPa and the C／N ratio of raw water was 10. The oxygen supply rate and nitrification rate were the main factors for COD and TN removal by AMBR separately, but both of the oxygen supply rate and nitrification rate influenced the NH₄+-N removal.

Abstract:Para-chloronitrobenzene degradation by Fenton-like with zero-valent iron and hydrogen peroxide was studied in depth for the purpose to solve the circulation of iron ions suffocated caused by the slow rate of Fe³⁺ returns Fe²⁺ in the traditional Fenton reaction. Different effects of hydrogen peroxide and iron dose, initial pH value and others factors were investigated. Para-chloronitrobenzene removal efficiency of 73％ was achieved under optimal reaction conditions of pH value 5, with dosage of 200 mg／L zero-valent iron, and 3.5 mg／L of hydrogen peroxide after 20 min. The Removal efficiency of para-chloronitrobenzene by Fe⁰／H₂O₂ Fenton-like increased 20％-30％ than the traditional Fenton reaction under the same dosage of iron and hydrogen peroxide, and the same of pH value. And in 3-7 range of the pH value, para-chrornitrobenzene degradation effects were obvious by Fe⁰／H₂O₂ Fenton-like. The choro-(—Cl) and nitro-(—NO₂) on the phenyl were transformed inorganic ions incomplete. The main intermediates were oxalic acid, glycolic acid, acetic acid, maleic acid, p-nitrophenol, p-chlorophenol, 2-chloro-5-nitrophenol, 5-chloro-2-nitrophenol. An degradation pathway of the para-chloronitrobenzene was also proposed.

Abstract:To study the transport and behaviour of short chain nonylphenol ethoxylates (NP_nEO, n=1,2) in anoxic／oxic (A／O) process of municipal wastewater treatment plant, the distribution of short chain NP_nEO and NP in the aqueous phase and sludge of each unit process in a full-scale municipal wastewater treatment plant of northeast China were investigated using a solid phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS). The results showed that the influent NP, NP₁EO and NP₂EO were 1 3,1 784 and 891 ng／L, which were lower than those of other cities in China and many other countries, then the concentrations of three compounds increased and reached to the highest at aeration grit chamber due to the biodegradation of long chain NP_nEO, which were 3 6,4 228 and 2 066 ng／L, respectively, after that the concentrations of them were dropping down significantly at anaerobic sink because of the adsorption of activated sludge, and finally the effluent NP, NP₁EO and NP₂EO were 1,8 and 159 ng／L. It is concluded that the anaerobic sink made more contribution for the removal of these compounds in influent. In addition, the concentrations of NP, NP₁EO and NP₂EO in each treatment unit have a positive correlation with their TOC content.

Abstract:To reduce air emissions of polycyclic aromatic hydrocarbons (PAHs), which impose health threats and risk of cancer to humans, it is necessary to control the behavior of production and emission of enterprise, and by source apportionment, it is possible to make sure the PAHs emissions type of discharge contamination enterprises. By applying bilevel decision-making theories and methods of a hierarchy system, this paper presents bilevel decision models to collect charges due to emission of PAHs for different decision-makers of upper-level government and lower-level enterprises. This model has in some degree solved the inconsistent information happened in previous studies between government and enterprises, and can be used to better control the PAH emissions from enterprises and improve the air quality.

Abstract:To fulfill photocatalytic hydrogen production, Ag-doped ZnS photo catalyst was prepared by template hydrothermal method and solution infiltration and reduction method. The structure and optical property were studied by XRD, SEM and UV-vis, respectively. The photocatalytic activity of the catalysts was evaluated by splitting Na₂S+Na₂SO₃ solution into H₂. The results show that in acid bath with a small amount of template and a large amount of Thiourea and Zn(Ac)₂, the sample is of rod structure and exists mainly in the form of sphalerite; whereas the sample is of ball structure and co-exists in the form of wurtzite and sphalerite. In a base bath, ZnS is of rod structure and exists mainly in the form of sphalerite. EDS analysis indicates that a small amount of Ag is loaded on the ZnS. The sample A has mixed-crystallized structure with bigger red-shifted in UV-vis absorption spectrum, and the doped Ag is liable to separate the photo-induced e-and h+, which presents the best photocatalytic activity for H₂ production.

Abstract:To reduce energy consumption of buildings on heating and cooling, and to achieve long-term stable heating and cooling using solar-ground coupled heat pump system (SGCHPS) in severe cold zone, a method of depending on seasonal solar heat storage in soil was put forward to maintain soil heat balance and increase system efficiency. Long-term experiment of 3 years was carried out relying on a demonstration project of solar-ground coupled heat pump for heating and cooling in severe cold zone. The system configurations were determined according to the building load, and 4 modes were selected to operate alternately. The experimental results showed that SGCHPS with seasonal heat storage could make the room achieve indoor air design temperature, and the guaranteed rate of heating and cooling were 92.0％ and 84.1％, respectively. The energy efficiency ratio (R_EE) of heat pump was more than 4, the annual heating EER including the power consumption of heat storage was about 6, and the cooling EER was more than 20. The system operated stably for a long period, and could meet the heating and cooling demands of a detached house in severe cold zone (e.g. Harbin). Seasonal heat storage took full advantage of solar energy of the whole year, and increased system efficiency. The energy-saving effect was remarkable.

Abstract:To discuss the operating characteristics of a new kind of energy-storage air source heat pump when supplying hot water, the unit’s performance in different conditions was studied by experiments. The results show that the unit can operate efficiently and stably, and the unit’s mean REE reduces with the increase of hot water supply flux. There also exists a break of hot water supply because the high flow rate of circulation water causes intensive disturbance in the heat storage tank, and the time of break is prolonged with the decrease of outdoor temperature. Moreover, the heat supple ability and mean REE of the unit reduces with the decrease of outdoor temperature.

Abstract:Aiming to analyze traveler’s mode choice behavior under bounder rational, this paper introduced the prospect theory in the mode choice decision-making. First, the subjective perception cost of travelers with different time value on the three different transport modes, private car, bus and taxi, was analyzed, and the traveler’s mode choice behavior was discussed under the traveler’s generalized travel cost, the probability distribution of travel time changing and travel time constraints, respectively. Comparing the difference of numerical examples between prospect theory and expected utility theory, it indicated that the prospect theory is more dependent on the weighting function changes; and under the travel time probability changes and the time constraints, the car owners tend to choose private cars. The prospect theory is more applicable to analyze traveler’s mode choice behavior under the uncertain environments.

Abstract:The control equation of spherical cavity expansion theory of compaction grouting in saturated clay considering pressure filtration was derived to study the effect of pressure filtration on compaction grouting. Then the control equation was simplified to obtain the radial stress and radial deformation by assuming constant soil permeability, and the radial stress and radial deformation could be well calculated by simplified method. Compared with the theory in this paper, the traditional spherical cavity expansion theory can not consider the impact of effective stress ratio and pressure filtration, so that the lower effective stress ratio will lead to larger error. The results show that, with the increase of radius, the radial stress decreases notably. With the decrease of effective stress ratio, the radial stress of inner soil decreases and the radial deformation of surrounding soil increases. However, the effective stress ratio has little influence on the radial deformation of inner soil.

Abstract:In order to study the rheological properties of asphalt mixture, MMLS3 was used to conduct full scale accelerated loading test and PSPA was used to test seismic modulus of upheaval and sag when asphalt mixture came into the stage of flowing deformation. The test results showed that the sag and upheaval changed with different degree of variations under the loads, and the seismic modulus of sag increased gradually and tended to be stable, while the seismic modulus of upheaval decreased gradually. It can be proved that asphalt mixture presents non-uniformity rheological course and the change law of mechanical properties of upheaval is totally different from that of sag.

Abstract:To evaluate the dispersive performance of aged asphalt mixture during hot in-place recycling of asphalt pavement and guarantee the hot in-place recycling construction quality, a simple and easy-doing blending and screening test was designed. By in-laboratory blending and screening tests, the influences of different heating temperatures, different blending time and recycling agents on the dispersive performances of aged asphalt mixtures were evaluated. The results indicated that, the heating temperature of 120 ℃ resulted better dispersive performance of aged asphalt mixture than 110 ℃; the blending time of 2 mins resulted better dispersive performance of aged asphalt mixture than 1 min; and the recycling agent could improve the dispersive performance of aged asphalt mixture. Thus, higher heating temperature, longer blending time and good recycling agent can improve the construction quality of hot in-place recycling asphalt pavement.

Abstract:To reduce the vertical seismic response of vertical storage tanks with fluid-structure coupling motion,according to the boundary conditions and potential theory,the hydrodynamic was given by selecting reasonable velocity potential. Considering hydrodynamic and soil-structure interaction,the control equation of vertical isolation storage tanks was established and the theoretical expression of wall shear, bending moment and stress were given. Seismic response analysis was carried out with Wilson-θ method selecting 150 000 m³ storage tanks. The results showed that: a vertical base isolation system storage tank could reduce the seismic response of radius, axial and hoop stress. It is necessary to take various factors into account to select the best site, isolation period, damping ratio and height-radius ratio in design of different storage tanks.

Abstract:To study the lever-arm effects of missile, considering the missile missile-borne SAR under the premise of cost-effective, and the direct use of the motion parameters output from missile’s IMU,this paper designed SAR platforms without INS equipment, and got the actual SAR antenna center movement information, which was used to the SAR antenna center movement compensation. The motion transfer relationship of initial navigation to the antennary center was built up by considering of the vibration and lever-arm effects, and simulation analysis of validation was made.

Abstract:To study the shear performance of RC beams strengthened with prestressed CFRP sheets under load, three groups of reinforced concrete beams, total of 12, have been made according to the ratio of reinforcements. In each group, one beam has been chosen to take as contrast beam for single point loading to get experimental data on bearing capacity, as well as fracture distribution. Before the tests, as much as 0.4 times of ultimate shear bearing capacity to the other 9 beams was applied, then the test beams were strengthened at the shear section with prestressed CFRP sheet under load before. Based on the test data, the shear failure mechanism and effect factors of the beams were analyzed. The test result shows that the prestressed CFRP sheets at inclined section could restrain the generation and development of cracks, increase the height of the compression concrete in compression-shear area, as well as improve the shear bearing capacity of inclinded section.