Abstract:To predict the bridge structural reliability based on the monitoring information and the priori model of stress parameters (mean), the dynamic measure of structural stress over time is treated as a time series, and considering the limitation of the BDLM, a Bayesian dynamic nonlinear model (BDNM) is then introduced. State equation and monitoring equation of monitoring stress are established with BDNM. Then the BDNM is approximately transferred into Bayesian dynamic linear model (BDLM) by Taylor series expansion technique, and the monitoring information is monitored by bayes factor. Combining parameters’ prior information with the early stress data containing noise, the stress state parameters are deduced with Bayesian Posterior Probability. A dynamic model is built to forecast the changing trend of structural stress. To allow for the epistemic uncertainty in variance estimation based on monitoring information, a discount factor approach is made for specification of unknown variance. Finally based on the built BDNM and the FOSM method, the structural reliability is predicted, and the feasibility and application of the built model is illustrated by an actual example.

Abstract:To predict the failure load of masonry wall panel, this paper extracts the strain energy density from the finite element analysis (FEA) of masonry wall panel under the evenly distributed unit load and develops a concept of generalized strain energy density (GSED). Then, by analyzing the GSED modes of both base and new panels, and the relationship between the failure loads of two panels is revealed. Hence, a GSED-based method is proposed. The case studies show that the GSED-based method is much more accurate than the yield line method. Comparing with the FEA method, the GSED-based method has nearly the same accuracy but a low sensitiveness to different material properties. Besides, The GSED-based method can directly apply the experimental data to predict the failure load of new panel, which provides a new way for predicting task.

Abstract:To compare the pros and cons of reinforced concrete block masonry shear wall structure(R.M. system) with reinforced concrete short-limb shear wall structure(R.C. system) in the area of carbon emissions, both structural systems were used for the structure design of a 17-storey residential building, and the detailed analysis of the structure performance, project cost and carbon emissions in the process of material production, transportation and construction was carried out. The results show that using the R.M. system for the construction of Multi-storey residential buildings can gain similar structure performance to the R.C. system, and at the same time reducing the project cost by 10.9％, reducing the emissions of Carbon Dioxide by 47.76 kg／m²(10.0％). Comparing with the R.C. system, the R.M. system has the advantage of less carbon emissions and energy consumption for the construction of high-rise residential building, and it’s a kind of green building system with the property of ‘resource-saving, environment-friendly’.

Abstract:Insufficient insolation condition is one of the urgent problems to be solved in north China because of its cold climate and smaller solar elevation angle. To improve this situation, we are working on a theoretical model for optical facilities based on the principles of rays refraction, which can concentrate solar energy from larger scope to smaller scope, then insolation standard can be improved in the specific region. A theoretical model on the structures and working principles of the insolation lens is explained in detail, its validity is proved by optical simulation, and trajectory of rotating Insolation Lens is analyzed at length. This theoretical model could improve the insolation conditions of the existing residential buildings and reduce the land use in the urban construction processes.

Abstract:Many researches focus on the ecological water demand accounting problem. But it has a certain restriction of several potential evapotranspiration models commonly used in China and abroad. Combined with the northeast area characteristic, the paper has chosen Harbin as the example. It has selected a series time of indicator data and compared the applicability and disadvantage about these models. The paper proposes the method to amend and optimize the Hargreaves (HM) model. It also revised the parameters. The correlation coefficient of amending HM and the PM calculations is 0.826, and the relative mean squared deviation is 0.119. It has a good correlation of calculating the evapotranspiration calculation of Harbin. And it will lay the foundation for the quantitative accounting ecological water demand of the northeast region.

Abstract:Aiming at the membrane fouling problem produced during MBR working process, different controlling operations were used on two sets of parallel A／O-MBR systems (R1 and R2). The changing situation of the microbial community structure during the membrane pollution process was analyzed by T-RFLP method, and the microbial metabolites were quantified. The results show that under the different operational conditions, the dominant microbial species of Cake layer in R1 system (controlling method: temperature is 30 ℃; SRT is 60 days; Flux is 9.09 L／(m²·h); DO is 4 mg／L) is Oribacterium, Cytophaga sp., Anaeromyxobacter, Paracoccus, bp180 and Comamonadaceae, respectively. The membrane fouling cycle of R1 reactor is 30 days. The dominant microbial species of Cake layer in R2 system (controlling method: temperature is 20 ℃; SRT is 30 days; Flux is 13.42 L/（m²·h); DO is 2 mg／L) is Anaeromyxobacter, Oribacterium, Saprospiraceae and Myxobacterium, respectively. The dominant microbial species of membrane wire in R1 is Saprospiraceae, Nitrospira, Thiothrix sp. and bp92, respectively. The dominant microbial species of membrane wire in R2 is Thiothrix Eikelboomii, γ-Proteobacterium, Nitrospira, Thiothrix sp. and bp52, respectively. The membrane fouling cycle of R2 reactor is 11 days. The different running methods on A／O-MBR systems have a significant influence on the succession of microbial community. The ascending of microbial diversity Shannon index H of Cake layer and membrane wire may accelerate the membrane fouling process. The obvious increasing trend of microbial metabolites(EPS,SMP) content results in the membrane pollution getting worse. EPS of the Cake layer has a dominant contributive effect on the process of membrane fouling.

Abstract:A laboratory-scale A²O process treating domestic wastewater was carried out to investigate the influence of amoxicillin on nitrogen and phosphorus removal in pharmaceutical park wastewater treatment plant. The removal efficiency of COD, nitrogen and phosphorus had been studied before and after adding amoxicillin to influent. The result revealed that the activity of organism degrading bacteria was significantly inhibited and the average removal efficiency of COD decreased from 86.9％ to 79.5％ by the impact of amoxicillin (2-5 mg·L-1). The activity of nitrate bacteria was not inhibited while nitrite bacteria was significantly inhibited that the nitrification activity had been declining. The average removal efficiency of ammonia decreased from 95.5％ to 85％. The anaerobic phosphorus release, the denitrification performance and the removal efficiency of total phosphorus and total nitrogen was slightly affected.

Abstract:To inquiry the factors of removal efficiency of different-concentration TiO₂ NPs by coagulation processes and the difference between different-concentration TiO₂ NPs and turbidity in removal performance. This paper investigated the impact of sonication pretreatment and surfactant (LAS) on the stability of TiO₂ nanoparticles (NPs) in solution firstly, for getting dispersion stabilized suspension. We also studied the effect of dosage of coagulant (PAC) on different-concentration TiO₂ NPs based on jar test, and the dependence of surface zeta potential on pH.The results demonstrated that the best stability of TiO₂ NPs was obtained at sonication power of 250 W for 10 min under LAS concentration of 20 mg／L. The removal of TiO₂ NPs and turbidity exhibited the similar trends under various coagulant concentrations. The optimum coagulation dosage was 3 mg／L at initial TiO₂ NPs concentration of 0.5,1 and 2 mg／L, which corresponded to removing efficiency of TiO₂ NPs and turbidity of 46.2％, 60.2％, 68.8％ and 23.2％, 43.6％, 47.6％ respectively. The optimum coagulation dosage of 4 mg／L for initial TiO₂ NPs concentration of 5 mg／L resulted in removal of TiO₂ NPs and turbidity of 77.6％ and 54.1％. The pH value was found to have significant impact to Zeta potential, and then has influence on the removal effect of TiO₂ NP.

Abstract:To improve the growth and survival rate of plants in vegetation-growing concrete, we chose two kinds of arbuscular mycorrhizal fungi, Glomus mosseae and Glomus intraradices, to study the effect of pure fungi, mixed bacteria on Poa pratensisl. cv. BALIN in vegetation-growing concrete. The results show that: The single application of Glomus mosseae (GM) can obviously improve the infection rate to 43.27％. Poa pratensis has stronger dependence on Glomus mosseae and mixed fungicides (MI) with little difference than Glomus intraradices (GI). The plant height and aboveground biomass with MI treatment can be increased by 15.8％ and 20％ respectively. Mtreatment can increase the underground biomass by 48％ higher than any other treatment. M treatment can significantly improve the proline and soluble sugar contents by 45.4％ and 27.7％ and reduce the malondialdehyde content (MDA) by 14.7％ which can enhance the plant stress-resistance. M treatment can make the plants get the highest CO₂ assimilation and water use efficiency (WUE), enhancing Poa pratensis’ ability of using the light and water and improving better growth of plants. Glomus mosseae is the best choice to improve vegetation-growing concrete.

Abstract:To evaluate the effect of aerated grit and degreasing tank(AGDT) with long hydraulic retention time (>10 min) on nutrient and phosphorous removal performance at municipal wastewater treatment plant(WWTP), influent characteristics, effluent quality, removal efficiencies, activated sludge characteristics and composition, as well as performance assessment based on mass balance evaluation, were investigated in a full-scale WWTP. The experimental results showed that: Compared with Pista grid pre-treatment, AGDT pre-treatment was unsuitable to be used in WWTP with low C／N rate wastewater because it consumed more carbon source and led to decrease of effluent COD／TN／TP rates; The total nitrogen(TN) removal efficiency and total phosphorus (TP) removal efficiency decreased 5.87％ and 10.22％; The activated sludge characteristics and composition were changed with TN content increased and TP content reduced; Mass balance evaluation approach also showed that the available carbon source was decreased in secondary biochemical treatment after AGDT pre-treatment. Therefore, the effect of AGDT with long hydraulic retention time (>10 min) on full-scale WWTP nutrient and phosphorous removal performance was negative.

Abstract:To solve the problem of agglomeration, low catalytic activity and difficulty to recycle and utilize of the 1-D, 2-D nanomaterials during the process of degradating organic pollutants.3-D TiO₂ nanoflowers with chrysanthemum structure were prepared by template hydrothermal method in which TiO₂(P25)and NaOH as raw materials, with assistance of ZnO nanostructure templates. Petals in nanoflowers were self-assembled and arranged directionally by TiO₂ nanoparticles.The TiO₂ nanoflowers was characterized by scanning electron microscopy(SEM), X-ray diffraction(XRD), nitrogen adsorption-desorption, ultraviolet-visibles diffuse reflectance sepctroscopy (UV-vis DRS), Fourier transform infrared (FTIR). The SEM images indicated that TiO₂ nanoflowers were chrysanthemum shape and average particle size was 5 μm. Self-assembled nanoflower of the diameter of the nanoparticles was about 15 nm. It was confirmed by XRD that the TiO₂ nanoflowers was pure anatase crystalline structure with good crystallinity. The N₂ adsorption-stripping isotherm results showed that specific surface area was 102.3 m²／g and average pore size is about 17.41 nm. Methylene blue as the target pollutant, the photocatalytic degradation of methylene blue rate in 80 minutes could reach 98％ under UV irradiation. So photocatalytic activity of TiO₂ nanoflowers was higher than P25, and showing stronger photocatalytic degradation ability.

Abstract:In order to avoid the oxidation of ferrous ions to trivalent iron, as well as the inevitable error caused by the different color sensitivity of researchers, the total content of iron(Ⅱ) ions in the LiFePO₄ was determined by the potentiometric titration method, while the total iron content was determined by EDTA complexometric titration and spectroscopy method. The results show that the ferrous ion content in the LiFePO_4provided by factory is 32.703％, of which RSD is 0.059％(n=6), the 95％ confidence interval of iron (Ⅱ) is(32.703±0.062)％, and the content of trivalent iron is 1.235％. The potentiometric titration is a reliable method to measure the content of ferrous ion and trivalent iron in LiFePO₄.

Abstract:To characterize the mechanical behaviors of porous asphalt mixtures under loading at normal and low temperatures, a viscoelastic-plastic damage model, which includes Weibull damage function, Generalized Maxwell and Drucker-Prager model, was presented based on incremental constitutive equation. Experimental data from uniaxial compressive strength tests conducted at different strain rate and different temperature were used to validate the efficacy of the model, and the change rules of model parameters in different temperatures and loading rates were investigated. The test and analysis results show that parameters in viscoelastic model begin to behave like the elastic materials. The volume modulus and shear modulus also show obvious viscoelastic properties along with the changes of temperature and load rate. Additionally the strain plastic strain initializes keep almost same to the critical damage strain, which accommodate to the presented hypothesis. The damage curves of porous asphalt mixtures can also reveal the effects of different temperature and load rate. This model can successfully characterize the damage and mechanical behaviors of porous asphalt mixtures at normal and low temperatures.

Abstract:To study the affection of cast in-situ slabs in RC frames during earthquakes,this paper presents a low cyclic loading test for two spatial RC frames. The failure pattern, loading carrying capacity, stiffness degradation, deformation characteristic and energy dissipation capacity are experimentally studied. Research findings indicate that the loading carrying capacity of the frame with cast in-situ slabs increase and the deformation capacity decrease. However, the energy dissipation capacity changes slightly. The failure patterns of the frame with cast in-situ slabs changes from “strong column weak beam failure” to the “strong beam weak column”. The degradation of loading carrying capacity decreases and the stiffness degradation increases due to the effect of slabs. All the frames exhibit good seismic performance.

Abstract:To study the material behaviors of hot-rolled circle hollow austenitic 304 stainless steel members applied widely in large-span roofs, both smooth and notched round specimens were cut from Φ216×16 mm tubes and tested under monotonic tensile and cyclic axial loadings. Stress-strain curves were obtained to determine basic material parameters as well as load-displacement hysteretic responses and skeleton curves. In addition, fracture micromorphology of the specimens was observed. It is shown that the properties of middle thick austenitic 304 stainless steel are not significantly influenced by hot-rolled forming process. The stainless steel exhibits extensive strain-hardening and higher energy dissipation capabilities under cyclic loadings. As a result, kinematic-isotropic composite hardening material model should be adopted to simulate nonlinear response of this material. Cyclic hardening material parameters are calibrated by test results and used well in the numerical simulations.However, the fracture micromorphology characteristic of the stainless steel is quite different from that of low alloy or carbon steel.

Abstract:Based on pseudo-static theory, improved horizontal slice method is derived for retaining walls in translational mode to investigate the influence of principle stress deflection on the earth pressure. The method considers the principle stress deflection of soil behind walls and the horizontal shear force between slices. The basic equations are established according to stress state and static equilibrium condition, and solved by using iterative search algorithm to calculate the slip surface shape, seismic active earth pressure distribution, earth pressure coefficient and resultant force point, then parametric discussion is taken. Numerical results indicate that the slip surface shape for cohesionless soil is approximately linear, so it’s quite reasonable to use the hypothesis of planar slip surface in simplified calculation. In addition, soil friction angle and horizontal seismic action significantly impact earth pressure distribution, instead, the influence of wall friction angle and vertical seismic action are relatively smaller. Compared with the traditional pseudo-static method, earth pressure distributions by two different methods basically agree with each other, but the curve from the improved horizontal slice method trends towards nonlinear increase.

Abstract:The combination of chlorine dioxide(ClO₂) and chlorine(NaOCl) or monochloramine(NH₂Cl) was used to degrade the formation of ClO₂-, when ClO₂ was used as an effective oxidant which could form undesirable oxidation by-products, i.e. ClO₂-. In this article, Mill-Q water was used, and the impact of NaOCl or NH₂Cl combined with ClO_2or ClO₂-on the yield of ClO₂-and ClO₂ were investigated by monitoring the residual of NaOCl, NH₂Cl, ClO₂ and ClO₂-. It was proved that when NaOCl or NH₂Cl combined with ClO₂, hypochlorousacid(HOCl) formed by NaOCl or NH₂Cl could react with ClO₂-, which was the reason that ClO₂-yield reduced and ClO_2yield increased, and the increase in ClO_2yield exceeded the decrease in ClO₂-yield. For the purpose of the highest reaction rate, the optimal ratio between NaOCl and ClO₂ was 3∶1, while it was 1∶1 between NH₂Cl and ClO₂. The appropriate ratios of residual NaOCl／NH₂Cl and ClO₂-for ClO₂-complete removal were found to be close to the value of 1 and 0.5 respectively. Furthermore, compared with NaOCl, equivalent yield of NH₂Cl had much more ClO₂ residual yield when reacted with ClO₂, and had faster reaction rate in any ratio. It can be concluded that the generation of ClO₂-is typically much lower and the residual of ClO₂ is much higher with combination of ClO_2and NaOCl or NH₂Cl when compared to the use of ClO_2alone. And the minimum ratio between NaOCl and ClO₂, NH₂Cl and ClO_2are 3∶1 and 1∶1 respectively when used in micro-polluted water.

Abstract:To investigate the main factor that influenced membrane fouling in ultrafiltration, a simulated process of powdered activated carbon and ultrafiltration (PAC/UF) was used to treat micro-polluted raw water and the sedimentation effluent. Membrane fouling characteristics of two samples, effect of particle size and dissolved organic matter on membrane fouling were investigated. The results indicated that PAC/UF process could mitigate the membrane fouling of the sedimentation effluent, but it could not alleviate the membrane fouling of raw water. Organics in the raw water were mostly hydrophilic organic-based small molecules, and it could not mitigate the membrane fouling of the raw water although the aromaticity and the dissolved microbiological products were reduced with the adsorption of PAC particles, which indicated that the adsorbed organic did not cause serious membrane fouling in the raw water. The particles in raw water, with a small particle size and high number, was thought to be the main factor that leading to the invalid fouling control function of PAC/UF process on raw water. Particle number and particle size distribution have a critical role in membrane fouling.

Abstract:To accurately obtain discrete relaxation time spectra of asphalt binders, an algorithm termed the improved windowing interconversion method (IWIM) is presented in this paper. The IWIM allows discrete retardation time spectra to be converted into discrete relaxation time spectra, and vice versa. Compared with the windowing interconversion method (WIM), the IWIM affords a more exact distribution of time constants without generating negative spectrum lines. The IWIM was applied to the discrete retardation time spectrum of bending beam rheometer (BBR) test data for a conventional unmodified asphalt binder, successfully determining the discrete relaxation time spectrum. The result of the validation by means of a BBR test finite element simulation shows that the discrete relaxation time spectrum from the IWIM can well reproduce the stress relaxation properties of the asphalt binder.

Abstract:To analyze the dynamic characteristics of U-type road under moving vehicles, the coupled vibration problem is decomposed into two independent motion system, i.e. vehicle vibration subsystem and road vibration subsystem. The displacement coordination equation of wheel and pavement is used to consider the contact of vehicle and road. Based on the formula derivation of vehicle vibration differential equation, the dynamic responses of U-type road is analyzed and studied with the 3-D spatial distribution of road surface roughness considered. The results show that the fluctuation of vehicle-road coupling force is small when the road surface is smooth. The vehicle-road coupling force increases rapidly with the deterioration of road conditions. The forces of left wheel and right wheel is different under the non-uniform excitation of road surface roughness. Vehicle speed has little effect on the dynamic load coefficient comparing with road surface roughness. The impact of vehicle load should be considered under poor road conditions.

Abstract:To enhance further the stability of traffic flow, based on the FVD (full velocity difference) model,a new car following model named BL＆OVD model is proposed by incorporating the synergy effect of backward looking and optimal velocity difference information. By applying the linear stability theory, the linear stability condition of the new model is obtained and the modified Korteweg-de Vries (mKdV) equation is established with nonlinear analysis to describe the propagating behavior of traffic jam near the critical point. The simulation results show that the amplification of random disturbance signal in traffic flow can be reduced effectively with the new consideration, which means that the proposed approach can stabilize the traffic flow and suppress the traffic congestion. The new model can stabilize the traffic flow further, and help to design the vehicle driving strategy in the autopilot system.

Abstract:To solve the problems of building diversity evaluation system for different task and coupling relationship between different measurement indexes, a multi-agent evaluation frame work about effectiveness of naval ship was proposed. The method of model construction about measure of effectiveness of complex system was presented firstly, which can deal with the problem of the coupling relationship between different targets. Then Hierarchical control model was built based on that model. Task breakdown mechanism based on ship work breakdown structure (SWBS) and application of fuzzy set theory to solve the issue of multi-task coalition parallel generation was presented. Agent which had the strongest ability was chosen to compose temporary federate. Utility allocation of federate software without preferences to evaluation effectiveness of naval ship was presented. The weight of index by the method was objective. At last the paper proved the feasibility and effectiveness of the method.