Abstract:Soil spring constant of buried pipeline-soil longitudinal dynamic interaction based on theory and shaking table test is presented. According to one-dimensional SH wave motion theory in cylindrical coordinates ,Matsubara&Hoshiya’s theoretical expression is reinterpreted. Based on shaking table test data of buried pipeline –soil dynamic interaction subjected to small earthquake excitation(0.1g), the soil spring constant is analyzed. The results show that on this test condition the two values of soil spring constant are similar ,and the relative deviation is about 7.4% , that verifies the rationality of theoretical solution . Furthermore, soil spring constant at small slippage between pipeline and soil is recommended for engineering application, that is 0.6G-2.0G(G=soil shear modulus).

Abstract:This paper uses the infinite element to model the far field and the finite element to model the near field of foundation, and the equivalent load is artifically applied to the interface between the finite element and the infinite element to replace the seismic action. The seismic response of semi-infinite foundation are then simulated. Numerical results show that the proposed methodology based on the infinite element and the equivalent load method is feasible and can effectively simulate the process of wave propagation in semi-infinite foundation. Besides, the effect of gravity on the seismic response of free field is analyzed. Finally, the effect of soil-structure interaction on seismic response is also investigated via an engineering example of nuclear plant foundation.

Abstract:Silt has special engineering characteristics between clay and sand. To study the dynamic response of silt subgrade under long-term traffic loads, a dynamic FEM analysis based on a constitutive model that can describe the developing process of accumulated deformation was conducted. It is shown that large accumulated deformation occurs during the long-term traffic loading process. The additional stress transferred to the silt subgrade decreases greatly when passing through the pavement structure. Then, the addition stress decreases further to about 10% of the maximum additional stress within the silt subgrade with the thickness of 1.5m. Therefore, the subgrade with the thickness of 1.5m can be considered as the principal working area to sustain the traffic loads.

Abstract:Combining the risk analysis and monitoring measurement system, we identify the factors of risks and determine the risk evaluation index system, the amount of items in various weights was conformed by analytic hierarchy process, then, we introduced the fuzzy theory, the measurement of specific data for fuzzy comprehensive evaluation was completed by creating reasonable membership function, and the comprehensive risk index was obtained through the weights analysis and risk endowing system, thus, we established a dynamic risk assessment model for NATM construction in mountain tunnel. The model can quantify the measured data as a single dynamic risk index, and evaluate the risk of construction dynamically. The dynamic risk assessment system has been applied in Bao Fu highway tunnel, which can reflect the risk of tunnel construction process visually and timely. Analytical results show that the method is reasonable and practical, and is worthy of to be promoted and applied in similar projects.

Abstract:In order to study reinforcement mechanism and soil deformation law during dynamic compaction, the half model test box, the miniature earth pressure meter and the semicircle model hammer were specially designed, and the indoor model test was carried out. According to the test results, the variation of the dynamic stress and displacement in the soil were analyzed, and the effects of various dynamic compaction parameters on reinforcement effect of were evaluated. It can be seen that the single crater depth and the single influence depth under a specific impact energy level are gradually decreasing with the increase of the drop number; however, the total crater depth and the influence depth are gradually increasing. The influence depth is decreasing with the increase of drop height. The crater depth and the influence depth are gradually increasing with the increase of impact energy, and the ratio of them is between 3 and 4. With the increase of the hammer diameter, the influence depth is gradually decreasing, but the influence width is increasing, which is mainly attributed to that the impact stress on the unit area is decreasing.

Abstract:Based on the data including the yield strength, the dimensions of sections and the load-carrying capacity of existing experiments on axially-compressed members, eccentrically-compressed members and bending members，the uncertainty of material strength, geometric characteristics and calculation mode of S280 cold-formed thin-walled steel with thickness no more than 2mm was analyzed. Then, the improved second-order moment probability method was used to check the required reliability index of S280 cold-formed thin-walled steel sections with thickness no more than 2mm using the resistance partial factor in current codes under deferent load combinations. The results show that, using the recommended resistance partial factor in current codes, the reliability indexes of the axially-compressed members, the eccentrically-compressed members and the bending members with width-thickness ratio within the limitation of current codes can well meet the target reliability index. Finally, the recommended design strength value of S280 cold-formed thin-walled steel sheets with thickness no more than 2mm was proposed for structural design.

Abstract:The dowel-type connection with slotted-in steel plates widely used in modern timber constructions is one of the most efficient connections for heavy timber structures. To understand the mechanical properties of this type of connection well, 11 specimens with different number and spacing of steel plates and different dowel diameters were tested. The mechanical properties and failure modes of the connections were investigated. And influence of the parameters such as the number of steel plates, the spacing of steel plates and the dowel diameter were also studied based on the test results. The results show that the bearing capacity of connections with the same dowel diameter increased as the number and spacing of steel plates increased. The estimating formulas for the load-carrying capacity of connections were developed based on the European yield theory and the principle of superposition. The theoretical results show good agreement with the test results

Abstract:In order to study the approach and effectiveness of using mixed effects logistic model to estimate transition probability matrices for pavement deterioration modeling, a mixed logistic model is used to establish a dynamic relationship between pavement transition probabilities and explanatory variables such as pavement age, thickness, traffic level and random intercepts. A case study focused on applying the model with real data is conducted. The comparison results show that:(1) The impact of pavement types, environmental factors, traffic loading, and other relevant factors can directly considered and a non-homogeneous transition probability matrix, which varies with time and yield better predictions, is derived by using mixed logistic model. (2) Unobserved heterogeneity which comes from measurement errors and unobserved factors across different individual pavement sections is captured by random effects, and then bias and inconsistency of estimates are reduced to an acceptable small level. (3) Different individual pavement transition probability ,which can be used to predict a given pavement performance, is obtained by estimating random effects parameters in the mixed logistic model, especially when the size of the date set is insufficient or work of modeling individuals is heavy, inefficient traditional approach cannot provide unbiased, consistent, and efficient model estimators.

Abstract:The objective of this paper is to establish novel quantitative performance measurements for SBS (styrene-butadiene-styrene block copolymer) modified asphalt based on microstructure pictures of asphalt specimens. By magnifying pictures 400 times via microscope, two new measurements including area ratio of modifier and homogeneity of modifier distribution were tested for asphalt specimens with three vary modifier. Then the relationship between two new measurements and traditional measurements including penetration number, ductility rotational and viscosity rotary were investigated. The results indicated that they have a good correlation. It was concluded that quantitative measurements through microstructure pictures are a reliable and relatively easy method to evaluate performance of asphalt.

Abstract:This paper describes a specific laboratory test method for measuring asphalt mixture shear resistance, which was denominated as co-axle shear strength test. The test rationality and reliability was discussed and emphasized, with correct analysis and description of stressed characteristics of asphalt pavement. According to finite element analysis results and co-axle shear test specimen failure plane, the position of max shear stress was determined then. Defining the max shear stress in specimen under 1kN unit vertical loading as shear strength coefficient, which was hardly influenced by mixture modules in normal temperature range from 15℃ to 60℃. Then shear strength coefficient was given as a constant and equals to 0.14MPa/kN. Following these, the regression analysis of laboratory test results shows good relationship between co-axle shear strength and permanent deformation or DS.

Abstract:Four kinds of hot-applied sealants and two kinds of silicone sealants are tested by low-temperature extension test according to the transport industry standard to evaluate the low-temperature stress relaxation performance of the asphalt pavement crack sealants. The stress relaxation tests are started when the strain of the sealants is up to 50%. The three-parameter solid model is used to analyze the test data. The results show that the viscoelastic behavior of the sealants could be modeled very well by the three-parameter solid model, and two parameters of the solid model, maximum relaxation rate and relaxation time, which represent the viscoelastic characteristics of the sealants, has the potential of evaluating the stress relaxation performance for different sealants, though the fitting process is very complex. Furthermore, a relaxation index is defined in this work. The evaluation results with this index have no big difference with the results from the viscoelastic parameters. However, the relaxation index is more feasible and easy to use. The relaxation index can be used as a supplementary indicator for the low-temperature performance evaluation of the sealants on the basis of the transport industry standard.

Abstract:CVIS (Cooperative Vehicles Infrastructure System) is different from traditional traffic circumstance and traditional traffic flow models which are based on traditional traffic circumstance are not adept to describe the traffic flow characteristics in CVIS circumstance. Concepts and attributes list of VMA (Vehicle Multi Agent) are presented at first. Then, decision strategies in both traditional circumstance and CVIS circumstance are compared to analysis differences in traffic status judgment and decision at intersection and link between two circumstances. Based on those, single lane traffic flow models in CVIS circumstance are presented in this paper. Microscopic traffic flow models such as acceleration and deceleration are given in this paper. Furthermore, the intersection impacts are also considered in this paper to analyze signal influence. The numeral experiments analyze the trajectories and macroscopic parameters, such as total travel time, average travel time and average delay, in both circumstances. The results show that VMAs in CVIS circumstance have great decline in total travel time, average travel time and average delay time which indicate that vehicles in CVIS are more stable and successive than those in traditional circumstance. Beside, velocity variances in CVIS are lower than those in traditional circumstance which increases the fleet stable.

Abstract:To address the inefficiency and non-real time of shortest path problem with large scale traffic road network, an efficient algorithm was developed under time-dependent road network which represents road network and traffic information. Based on TDCALT (Time Dependent Core-based A * landmarks triangle inequality) algorithm which outperforms existing algorithms, improvement including updating upper bound dynamically and combining improved pruning strategy used in static shortest path algorithm was proposed. Finally a new algorithm called ITDCALT was formed. Comparative analysis between ITDCALT, TDCALT and TDIJKSTRA in time-dependent road network of Guangzhou shows that our algorithm outperforms the others in terms of efficiency, search space and stability.

Abstract:Chongming, the largest estuarine alluvial island in the world, received more and more attention home and abroad because of its ambitious development target of international ecoisland. This paper presents an integrated approach to analyze industrial development by combining SWOT analysis and Diamond Model, which is applied to exploring the feasibility of renewable energy industry development in Chongming Ecoisland. The main findings are: 1) it is not easy for Chongming to develop renewable energy industry in a short term, while a long-term strategy is more feasible. 2) The most important thing in developing renewable energy industry of Chongming Ecoisland is to get staggered development in a coordinated and complementary way; 3) Chongming has good external environment and relatively strong need to develop renewable energy industry; 4) There is lack of factors of production and support from related industries. And Clear strategy and core competence are also absent. 5) Renewable energy industry is of great potential in Chongming if policy is really implemented and external resources are fully utilized.

Abstract:Removal process and efficiency of organic substances in effluent from a municipal sewage plant were investigated and compared in a horizontal subsurface constructed wetland with different substrates by application of gel filtration chromatography (GFC) and three-Dimensional Excitation Emission Matrix Fluorescence Spectroscopy (3D-EEM). The results show that weight average molecular weight (Mw) of dissolved organic matter (DOM) in the outflow of the constructed wetland was significantly decreased, as compared to the inflow. After sewage plant effluent was treated by the subsurface wetlands, the percentage of the larger molecules > 50 kDa declined by 33.5%, while the percentage of the smaller molecules below 50 kDa showed a significant increase. Four different types of peaks such as aromatic protein-like compounds, soluble microbial byproducts, fulvic acid-like compounds, visible fulviclike and UV fulvic-like compounds in DOM from the infow significantly decreased in the effluent during purification by the subsurface constructed wetland. Especially, the biorefractory humic-like compounds can be effectively removed by the subsurface constructed wetland. Aromatic structures of humic-like compounds were weakened and organic compounds with benzene rings were decreased in the outflow of the subsurface constructed wetland. By comparison, organic matter transformations from larger molecular weight to smaller molecular weight were completed in the 1/4 front of the constructed wetland filled with ceramisites, while for the constructed wetland with zeolite substrate, the transformations were completed after the middle of the wetland bed. As compared to zeolite substrate constructed wetland system, ceramisite wetland was more effective to transform the organic matter from larger molecular weight to smaller molecular weight and remove the organic substances from the sewage plant effluent.

Abstract:Removal rates of Cd2+ from sewage prepared in laboratory by synthetic nano-Cryptomelane under several factors were measured. The effluence of each factor on the rates was studied. The results showed that it took 2h before the removal process reached balance; when the concentration of Cd2+ was 50 mg•L-1, pH=6.50, 2 g•L-1 of the adsorbent dosage, 2 h of the adsorption time, the removal rate of Cd2+ was 90.6%. The adsorption isotherm was fitted by Langmuir model, and the theoretical maximum adsorption capacity was 120.5 mg•g-1 when the concentration of Cd2+ was less than 300 mg•L-1. The mechanisms of surface coordinate reactions, surface electrostatic adherences and ion exchanges are co-existing to remove Cd2+ from the solution treated by the synthetic nano-Cryptomelane.

Abstract:Cube specimens and special bond damage specimens were designed and cast with C100 high-strength concrete (HSC). Residual compressive strength of concrete cubes as well as bond strength based on damage testing were examined after being exposed to 200℃, 300℃, 400℃, 600℃ and 800℃, and the relationship between transverse pressure and bond strength was analyzed. Furthermore, the detailed investigations were carried out on the appearance characteristics of specimens and degradation for mechanism of bond strength, which could provide technical support and theoretical basis for both evaluating or strengthening and repairing the concrete structure after fire.

Abstract:Compared to the ordinary Portland cement, geopolymer is a new type of cementitious material which is a low carbon, energy and natural sources saving material. In this paper, the feasibility of a complex geopolymer prepared from high-calcium fly ash and thermally-treated sludge was studied, and the performance and mechanism of the geopolymer were also studied. The results showed that compressive strength of the geopolymer was better when 10% fly ash was replaced by thermally-activated sludge (<45 m) at 900℃ for 1 hour. In complex geopolymeric matrix, amorphous geopolymeric gel covered around spherical fly ahs granule, the Zeolite-like mineral formed, meanwhile, the asymmetric stretching Al-O/Si-O bonds and Si-O-Si/Si-O-Al bending band appeared. This work is beneficial for extending raw materials of geopolymer, and also for utilizing of multi industrial wastes, especial the wastes containing silicate-aluminum phase and calcium.

Abstract:Abstract: Cu-Al composite row was produced by continuous cast-rolling technique and metallurgical bonding interface was achieved. The composite row shows excellent mechanical property and conductivity: overall tensile strength of 102MPa, resistance rate of 0.0216Ωmm2/m. The composite annealing temperature and thermal cycling influencing on the interfacial bonding strength were researched. The microstructure of interface and the composite mechanism was analyzed by SEM, XRD and Metallurgical microscope.

Abstract:Magnetic and temperature-responsive polymer microspheres, consisting of superparamagnetic Fe3O4 nanopaticles and temperature-responsive poly(N-isopropylacrylamide-co-acrylamide) (PNIPAAm-co-Am) microgel, were prepared by soap-free emulsion free copolymerization. Their heating generation abilities and drug release behaviors were investigated under an AC magnetic field of 60kHz and 6.5kA/m. Results showed that the as-synthesized Fe3O4/(PNIPAAm-co-Am) composite microspheres exhibited high heating generation ability. The temperature of 42°C, which is close to the lower critical solution temperature (LCST) of the temperature-responsive polymer, was achieved after the composite microspheres were exposed to an AC magnetic field for 20min. The drug release profiles showed that longer release duration and larger overall release could be achieved by intermittent application of a magnetic field as compared to continuous magnetic field. With high heating generation ability and controlled drug release property, such Fe3O4/(PNIPAAm-co-Am) polymer microspheres are promising for the combination of tumor hyperthermia and controlled release of chemotherapy drugs.

Abstract:The entire process of time waveform replication (TWR) for multiple-input multiple-output (MIMO) system is presented. The procedure of system identification based on frequency response function (FRF) and target signal iteration based on frequency-domain iteration learning control (ILC) algorithm is illustrated. The frequency-domain iteration learning control algorithm through setting proper overlaps and sections of the signals is proposed for control software development of vehicle road simulation test rig. A real 4-post test rig for road simulation test is chosen, and time waveform replication of vertical spindle acceleration signals of a vehicle is successfully achieved with the proposed algorithm. The result shows that the algorithm gets high precision and it could be used to control the test rig.

Abstract:To explore temperature field distribution and the corresponding mechanism in heating process and cooling process, the steady surface temperature of rolling tire is experimentally measured by a rotating drum test and infrared thermal imager under different conditions. The effects of speed, load and tire pressure on tire steady surface temperature are analyzed through orthogonal experiment, and the main and secondary factors effecting tire steady surface temperature are determined. The results show that: load is the maximum factor on temperature rise; the highest surface temperature is located at tire shoulder in heating process; there is a dramatic heating process in tire surface in cooling process.

Abstract:Blend fuels of ethanol and diesel have an advantage of decreasing request of petroleum resource and diesel engine exhaust emissions. But the molecular polarity of ethanol and diesel are different, it’s hard to form uniform and stability blend fuels without solubilizer. First, butanol, heptanol, biodiesel and sorbitan monooleate were chosen as the solubilizers. The solubilization capacity of these solubilizers were researched. Then the experiments on the ethanol-diesel blend fuels in different ethanol volume percentages (10%, 20% and 30%) and temperatures (from 5℃ to 60℃) were conducted. The experiential formulas about density, surface tension and viscosity varied with ethanol volume percentage and temperature were generalized. Finally, the simulation research for the effect of ethanol volume percentages on the diesel engine performance was conducted. With the ethanol volume percentage increasing, the fuel atomizing process improved, wallfilm mass decreased, NOx and soot emissions decreased, engine power performance penalized, while equivalent indicated specific fuel consumption and combustion noise reduced. The comprehensive performance of the diesel engine is the best when ethanol volume percentage is 10%.

Abstract:Rectangular steel finned elliptical tube heat exchanger with low pressure loss and good heat transfer performance is used at Aero-acoustic Wind Tunnel. In order to estimate the acoustic performance of the heat exchanger, microphones are used to test the acoustic performance of the heat exchanger inlet and outlet at a model wind tunnel in the present study. The test results show that the difference of total sound pressure level between heat exchanger inlet and outlet is almost 8.9~10.7dB at five test velocities, and the frequency of aero-noise generated by heat exchanger is mainly in the low and middle frequency range. Further discussion shows that with increasing in the upstream flow velocity, the frequency of shedding vortex increases linearly, suggesting the existence of a constant Strouhal number for a given heat exchanger.

Abstract:Aiming at the problem of air-cooled condenser output limit, the spray humidification system is presented here to reduce inlet air temperature. In this paper, pressure-type spiral nozzle is chosen for inlet spray cooling, and experiments include nozzle flow rate experiment and spray cooling experiment with different layout of nozzles. Through analysis of experiment data, characteristic curve of nozzle flow rate is acquired. And through heat and mass transfer analysis of spray cooling, the cooling effect fitting correlation which evaporative cooling is major cooling mechanism. And the results of experiments under different layout show that the 500mm of row distance is better than 1000mm.

Abstract:The fabrication of nanodots spaced by half the wavelength can furthur put forwards the development of nanoscale length transfer standard. Focusing and deposition characteristics of quadratic optical lattice formed by two orthogonal standing waves with parallel polarization are numerically analyzed via particle optics model.The initial condition is selected stochastically. Three dimensional（3D）structures of nanodots are studied under different laser power and transverse Gaussian divergence.The effects on nanodots with different deposition positions are also discussed. It is shown that good numercal result can be obtained in immersion lens and channeling regime.Transverse angular distribution and the deposition position dominantly determine the quality of the nanodots.

Abstract:A new method for decomposing and measuring higher-order mode waves in ducts using single microphone is proposed in this paper. The method is based on a repeatable inspiriting sound source associated with a slowly moving microphone along central axis of the duct. Compared with previous research, some problems such as microphone matching can be avoided, and much more modes can be obtained. At first the basic principle of modes decomposition, as well as single-microphone measurement system is described. Then the effectiveness of this method is verified by comparing the test results with those of the standard measurement in standing wave tube. Finally some experimental studies in a 600mm square waveguide are discussed.