Abstract:Assuming the long lined tunnel as an infinite homogeneous beam resting on a Pasternak foundation, the governing equation of the dynamic problem can be established based on EulerBernoulli beam theory. Integration transform and Residue theorem are applied to solve the differential equation, thus the analytical solutions of displacement, velocity, acceleration, bending moment, shear force for long lined tunnels subjected to arbitrary dynamic loads are obtained. The specified solutions for harmonic line loads, moving line loads and travelling loads are discussed and compared with the exiting solutions, and therefore, the validation of the presented generic form of solutions is verified. Taking travelling loads as an example, parametric analyses are performed to investigate the influence of the velocity and frequency of travelling loads and the shear modulus of foundation on the tunnel dynamic responses. The proposed solution is of value for seismic design of long line tunnel.

Abstract:Dynamic characteristics of highrise buildings is analyzed in this paper with the help of shearflexural type cantilever beam model; and then, a structural characteristic parameter governing the mode of highrise buildings is given. Through the fitting analysis of fundamental mode shapes with different structural characteristic parameters, a simplified model of fundamental mode is obtained, which has a concise expression but can accurately reflect the prototype fundamental mode shapes of highrise buildings; at the same time, the method for determining the mode index which governs the shape of simplified modes is given. The simplified fundamental mode of this paper is applied in the windinduced vibration analysis of an actual highrise building; the result shows that, by using the simplified mode, the wind load distribution along the height of the building can be reflected more precisely and the computational accuracy of wind loads and windinduced responses of the building can be improved.

Abstract:A new type of torsional lattice shell composed of sixbar tetrahedral units is proposed in this paper. The configuration analysis shows that its form is simple because of the comparatively fewer members and the higher evacuation ratio. The shell has advantages both of singlelayer and doublelayer shells. Both static and stability analyses of the lattice shell with semirigid joints are carried out in this paper. It turns out that the upper chord members all carry loads in compression while the lower chord members all carry loads in tension. The web members are mainly in tension except for the ones close to the boundary. The members can be designed using similar sections due to the little variation between their internal forces, which makes the structure design convenient and helps improve the material using efficiency. The integral rigidity of the structure is good; its nonlinear stability coefficient is just a little smaller than its eigenvalue of the first mode. The steel consumption is comparatively small. This new structure can be applied in single torsional shells with two evacuation schemes, three kinds of torsional shells composed of four single shells and one kind of torsional shells composed of two single shells.

Abstract:In order to investigate the influences of different forms of reinforced section and initial load on mechanical behaviors of axial compression angle steel in steel tower following weld reinforcing process, two forms of reinforced section, square and Lshape, were selected. Under the four different initial load, the static load test of angle steel reinforced by welding was conducted. The loaddisplacement curve, the ultimate stability bearing capacity as well as the failure mode of reinforced angle steel were obtained. According to the static test, finite element models were established and the numerical simulation was carried out to take into account the indirect thermostructure coupling analysis method. Both the test and analysis results show that the failure mode of two reinforced sections are global bending buckling; Compared to the specimens with square cross section, Lshape specimens are more sensitive to the heat input, but ductility is poorer; If the nominal stress ratio of initial load is less than 0.3, the effect of initial axial compressive load on the ultimate stability bearing capacity of angle steel axial compression members reinforced by welding is negligible.

Abstract:back propagation(BP), radial basis function(RBF) and genetic algorithmback propagation (GABP) are used to train and predict the ultimate ductility index μΔeof dualenergy equivalent method. Five control parameters and PEER database and quasistatic test are used as training and prediction samples. BP and optimization algorithm of its node numbers in hidden layer and learning rate are compiled, RBF and optimization algorithm of its node numbers and central width are compiled. Genetic algorithm (GA) is used for optimizing weight wij and threshold θj in backpropagation (BP) to inhibit the local optimum, making relationship between testing data approximate to the real mapping principle. Algorithms is realized to predict μΔe of fullscale columns. Research indicates GABP has optimal adaptability and computing superiority, provide new method for structural damage evaluation.

Abstract:Physical experiments are carried out in a rectangular flume with a length scale of 20 models, and the velocity is measured in vertical particular depth. First, the velocity distributions in vertical direction are initial fitted by curves of the parabolic and logarithmic formula based on the theory of open channel flow and analyzed, the strongly affected zones, moderately affected zones and weakly affected zones are classified from the effect degree. Then, the formula coefficients are deduced by the method of Boxplot fitting, and the formulas of vertical velocity distribution are obtained with parabolic equation in strongly and moderately affected raft zones and coefficients of the former larger than the latter; however, the logarithmic equation is more suitable to weakly affected zones. Finally, the analysis on effect of aquiculture density leads to the conclusion on the parabolic coefficients and the range of logarithmic coefficients increase with the density increasement.

Abstract:Facing with the current taxi floating car data insufficient coverage and data quality issues, Baidu mobile navigation and bus GPS data is introduced based on the analysis of available data characteristics, Traffic Performance Index algorithm based on travel time and one method of road traffic operation evaluation based on Taxi, Baidu, Bus, multisource floating car data(FCD) fusion is proposed to conduct the road traffic performance assessment and congestion management. Multi-source data fusion rules and a fusion algorithm are constructed. Take Shenzhen as an example, the results show that the multi-source data fusion method proposed in this paper has a significant effect, which greatly improves the accuracy of fusion results, data coverage, data reliability and data sample size. Finally, the main application direction and preliminary application effect are put forward. The method proposed in this paper can provide reference for domestic and foreign cities to carry out traffic operation assessment.

Abstract:This paper utilizes the industrial computerized tomography to visualize and to calculate the microstructure change of concrete during cyclic freezethaw test. The results indicate that entraining air is the sufficient way for improving the frost resistance of concrete, and the suggested air content is 5%~7%. Also, the air void space directly affects the frost resistance of concrete, and concrete can well resist frost damage when the air void space is shorter than 238 μm. The airentrained concrete has significant amount of fine air voids with shortened air void space, and the fine air voids can release the ice forming pressure during freezing, thus protecting the concrete from frost damage. The ice forming pressure can barely release for nonair entrained concrete, and microcracks forms when the ice forming pressure exceeded the allowable stress of concrete, and finally results in material loss or frost damage.

Abstract:In order to automatically and accurately achieve multi-dimensional indexes such as depth, area and volume of the asphalt pavement pothole, the advanced three-dimensional line laser technology was used to scan indoor potholes with different sizes. The laser point cloud data collected was processed using the triangulated irregular network(TIN) plane interpolation method by Matlab software and was used to reconstruct the three-dimensional pothole model. Combined with contour extraction method, the pothole border was identified and multidimensional indexes of pothole were automatically calculated. The relative error of different pothole multi-dimensional indexes was compared and the effect of laser’s longitudinal spacing on relative error was studied. The results show that the maximum relative error of the pothole depth, area and volume are 3.96%, 4.58% and 4.74%, respectively. The relative error of pothole multi-dimensional index decreases with the increases of pothole size. When laser’s longitudinal spacing increases from 5 mm to 20 mm, the relative error of pothole multi-dimensional index increases by degrees. The maximum relative error of pothole depth, area and volume are 4.65%, 6.32% and 7.17%, respectively, when spacing is 5 mm. The relative error of pothole multi-dimensional indexes increases significantly when spacing becomes larger than 5 mm. Therefore, to insure the accuracy of multi-dimensional index detection, it is suggested that laser’s longitudinal spacing is less than 5 mm. The method of pothole multi-dimensional index accurately provides foundation for the pavement structural layers identification of damage distribution, evaluation of distress severity and estimation of materials rehabilitation.

Abstract:Homoacetogen is a kind of anaerobic microbial group which can utilize a variety of organic substrates and gas substrates(such as CO2,H2 and CO ) to form acetate, ethanol and other chemicals through acetyl -CoA pathway. They can survive in almost all kinds of ecological environment.With the depletion of fossil energy and the better understanding of homoacetogenic, it becomes more popular to apply homoacetogen into organic matter fermentation, syngas fermentation, and degradation of organic pollutants with nitrocellulose .Certain species of homoacetogen and their physiological and ecological characteristics are summarized in this paper. And the applications and research progress about homoacetogen in environmental biotechnology are also discussed thereafter.

Abstract:A soil column experiment was conducted to evaluate the effect of 3-year consecutive application of anaerobically digested sewage sludge (ADSS) on a degraded soil from a nursery garden in Hefei City, Anhui Province. Soil physiochemical and microbiological parameters were determined, and accumulation characteristics of heavy metals in the soil were also analyzed. The results showed that 3 years after the ADSS addition, soil texture and physicochemical environment were significantly (P<0.05) improved, and the soil total dissolved salt (TDS) content and electric conductivity (EC) were decreased by 67.6% and 45.3%, respectively, which indicates that the ADSS application showed a improved effects on the degraded soil with secondary salinization due to continuous nursery plantation for several years. The application of ADSS significantly (P<0.05) increased soil organic matter content and nutrients supply. After 3-year ADSS application, soil organic matter was increased by 77.9% and the available nitrogen and phosphorus were increased by 110% and 95.4%, respectively, as compared with the control (no ADSS addition). At the same time, the ADSS application also significantly (P<0.05) enhanced nursery soil microbial biomass and metabolic activities. As compared to the control, soil microbial biomass carbon (MBC) was increased by 207%, and soil urease and alkaline phosphatase activity were increased by 118% and 102%, respectively. The above results showed that the application of ADSS could improve the degraded nursery soil quality. In addition, the nursery soil with 3-year application of ADSS showed an increase in the contents of heavy metals, but the contents of the determined heavy metals were far lower than the secondary level of soil environmental quality standard of China (GB 15618—1995). However the effects of long-term application of ADSS on accumulation of heavy metals in the nursery soil and its ecological risk need further study.

Abstract:The multi-body dynamics model of the towed cable is proposed in the aircraft circular motion. Based on the analysis of motion state and force of the towed cable which is established via the multi-rigid method, the dynamic simulation analysis is carried out, and the steady configuration of the rotation balance is achieved. In the same condition, it is similar to the numerical calculation configuration of micro-element method of the continuous model. All these illustrate that the new dynamic model is correct and credible, and the simulation solution is also robust and accurate. Finally, the influence of various parameters on the vertical length of the towed cable is analyzed in detail. The simulation results show that the aircraft speed is the most important factor which affects the system’s efficiency, and with some certain conditions, reasonable reducing the aircraft speed can increase the vertical length of the towed cable. The effective speed range is also calculated by the dichotomy.

Abstract:This work investigated the feasibility of reusing steel slag as raw materials in preparing magnesium phosphate cement (MPC). The effect of steel slag on the setting time, hydration process, mechanical properties and microstructure of prepared cements was determined. The results show that the influence of steel slag on the performance of magnesium phosphate cement exhibits a similar trend as that of fly ash. The addition of 10% steel slag would accelerate the hardening of prepared cement due to the presence of CaO and the formed calcium hydroxide. The hardness of steel slag would also increase the compressive strength. With increasing the steel slag substitutional level, the content of hydration products would decreases, while the porosity increases and micorstructure become loose as a result. The hydration of f-CaO would do a detrimental effect on the mechanical properties of MPC. The hydration products detected in X-ray diffraction(XRD) patterns of steel slag blended MPC is the same as those of reference. However, there is more microcrack present in the hardened paste containing 40% of steel slag.

Abstract:A parametric model of 18 parameters was established and a global optimization method based on genetic algorithm was developed. The aerodynamic optimization of the vehicle body with internal flow was carried out and a low-drag optimization shape with aerodynamic drag coefficient of 0.261 was obtained. Comparing the results of numerical simulation and test, it is found that the difference in aerodynamic drag coefficient is only 4%. The surface pressure coefficient and different cross-section velocity contours have the same distribution and small difference of magnitude, which indicates that the numerical simulation method is correct and feasible. Through the energy decomposition of the flow field in the tail section using the Proper Orthogonal Decomposition, it can be observed that the first nine modes occupy 54.5% of the total energy. Among them, the first-order mode with the highest energy shows the shape of the tail drag vortex and its vortex position does not change with time. In this paper, the global optimization method of the vehicle with internal flow was established, and the low-drag model with internal flow was validated by test, which can provide a method and reference for the development of related products.

Abstract:Based on computational fluid dynamics(CFD) numerical simulation method, aerodynamic drag reduction of 25°Ahmed model with active flow control of steady jet are researched using shear stress transport(SST) κ-ω turbulent model. Jet holes are located at the model tail to study the optimum parameters of hole diameter, distance to the nearest side edge, shape, jet velocity and jet angle, and to analyze the influence of different jet state to the flow structure, total drag coefficient and local drag coefficient. In addition, the numerical simulation results are in good agreement with the date from wind tunnel experiment, which verifies the accuracy and reliability of present numerical method. The numerical results indicate that the wake structure with flow control is significantly improved and the longitudinal vortex is effectively suppressed, compared to the one without control. Simultaneously, the drag coefficient significantly decreases. In the scheme of placing jet hold on the single location, the one placing jet at the top of slant get the lowest drag coefficient 0.252 2 (with 11.3% drag reduction). The drag coefficient of the optimal combining scheme obtained by orthogonal experiment method is 0.246 7 (with 13.23% drag reduction).

Abstract:A numerical thermal-hydraulic model considering the mal-distribution of refrigerant-side is used to investigate a four passes parallel-flow condenser. The influence of different airflow conditions on the performance and refrigerant distribution characteristic of this condenser is given. The related airflow conditions are inlet blockage, front radiator and different number of cooling fans. The results are as follows. At 50% blocking rate, the middle blocking mode makes the most deterioration of the performance of the condenser, heat transfer rate decreases 47.9% and refrigerant pressure drop increases 335.5%. The different blocking modes have different effects on the flow distribution of the refrigerant side, and the unevenness of the refrigerant distribution caused by grille block is the largest. The partial air velocity reduction and temperature increase caused by a front radiator results in 24.1% decrease in heat transfer and 80% increase in refrigerant pressure drop of the condenser. The front radiator only influences the refrigerant flow distribution of the second pass. When total air flow is constant, different number of cooling fans have little effect on heat transfer and pressure drop, but the unevenness of the refrigerant distribution is obviously increased.

Abstract:In order to research the influence of bogie's hunting motion on car body shaking, a multi-rigid vehicle system model is established at first, and the local deterioration of lateral ride quality is reproduced. Secondly, the concept of modal coupling degree is defined based on the Euclidean Closeness which belongs to fuzzy mathematics theory. In order to reduce the coupling degree of the system, the suspension parameters of the vehicle are optimized. The results show that transverse coupling vibration occurs when the frequency of bogie hunting and the natural frequency of car body approach which can decreases the ride quality. The severe transverse coupling vibration is, the greater the degree of coupling is. The coupling degree of system can be reduced if the vehicle suspension parameters are appropriate. So that the transverse coupling vibration can be weakened and the local deterioration of the lateral ride quality will be eliminated.

Abstract:Based on project-time controlling and risk management theory, a time-risk controlling model has been proposed to solve the problem of high uncertainty in the early stage of mega construction project (MCP) from the consulting achievements for several airport megaprojects. Next, the model was applied to develop pre-stage schedules and risk lists for XY airport megaproject. Finally, the effectiveness of controlling method was proved by comparing the overall time-risks of XY airport and other two airport pre-schedules, and comparing the effect before and after implementation of the customized plan. The risk-based method improves the applicability of project time-controlling at the front-end, and provides a methodological guidance for early time control of MCPs.

Abstract:Research and innovation play an important role in development of high-tech companies. With the consideration of innovation process, this paper divides the operation of intelligent automobile enterprises into two stages by date envelopment analysis (DEA) analysis, i.e., stages of innovation process and production process. This paper measures the operational efficiency considering corresponding innovation process for companies in intellectual vehicle industry. Efficiencies of 24 related public companies are estimated by a two-stage DEA model during 2010~2015. The conclusions of the study that the efficiency of the innovation stage decreased slightly in 2013 and shows an increasing trend between 2014 and 2015. The efficiency of operation stage keeps constant. It is discovered that the comprehensive efficiency of enterprises is more relevant to innovation efficiency in the correlation analysis. Compared with the efficiencies of operational stage, innovation efficiency for each company is quite low, which indicates that there is still a huge gap between the benchmarking enterprises and other enterprises, especially for the companies of manufacturing advanced driver assistant system, automatic control and operating system. Moreover, the unreasonable funding and lack of R & D capability are the main reasons for the low efficiency of the innovation process.

Abstract:Considering spatial and temporal features of urban storms, a proper surface runoff coefficient is selected to measure the quantity of flowing water, which will be collected by inlets. The sequence of drainage consists of rainfall collecting, conveying and discharge through inlets, pipes and pumps respectively, referred to a cascade connection queuing system. According to their importance, an urban district is divided into several areas whose rainfall should be drained out within a restricted time determined by their importance. The time, as well as the cost of building and the operation of the urban drainage system (UDS), is set as constraints of a biobjective optimization model for the pump location problem. Then we develop an optimization algorithm, genetic algorithm integrated with Tabu algorithm, to solve this complex nonlinear allocation problem. A practical case study reveals that multiple cascaded connection queuing method can simulate the UDS well, and the quantity and location of pump stations, as well as storm recurrence period, plays an important role in designing an UDS.