Abstract:A discontinuous and continuous coupling numerical model was established for a reinforced soil walls with flexible/rigid facings on soft soil based on centrifuge modelling. In the numerical model, the wall and soft foundation were simulated using particle flow code (PFC) and fast lagrangian code (FLAC), respectively. The behavior as well as the internal and external stability of the wall was investigated. The results show that the numerical results such as the settlement of retaining wall, the horizontal displacement of wall facing, the vertical earth pressure at wall base, and the moment of rigid wall facing are in good agreement with the measured results in the centrifuge modelling. The wall suffers a large and differential settlement due to its own weight and the surcharge loading, but the overall structure is still stable, indicating that the reinforced wall with flexible/rigid facings can well adapt to the soft foundation. The stress concentration is observed at the end of the anchor at selfweight loading and surcharge loading, leading to the maximum settlement in the foundation. At surcharge loading, the rigid wall at the middle bears a tensile force outside the wall and the maximum bending moment, whereas the rigid wall near the bottom and the top bears a tensile force inside the wall and the comparatively low bending moment. The reinforced wall with flexible/rigid facings on soft foundation generally suffers from the external stability of the deepseated failure. The failure surface is composed of the Rankine failure surface in the unreinforced soil and a circular failure surface in the soft foundation. The internal stability of the walls with flexible/rigid facings indicates that the reinforcements are fractured from the bottom to the top of the wall in sequence following the slip failure of soft foundation, forming a Rankine’s failure surface along the end of the anchors.

Abstract:In order to investigate the failure mechanism of slopes with different types of joints, the contact model considering the bond size was implanted into the distinct element method(DEM) software. Based on the gravity increasing method, the failure processes were simulated, and the slope configuration, the distribution of bond breakage, and the movement of slip masses were analyzed. The results show that the sliding surface is formed from the failure of coplanar joint in the bedding rock slope, while the noncoplanar joint in the toppling rock slope. The toe of the slope is a weak area in both the bedding and toppling rock slope. Besides, the mid area near the slope surface in the bedding rock slope as well as the slope shoulder area in the toppling rock slope are flimsy. In addition, the DEM simulation is able to evaluate the stability of the slope like the limit equilibrium methods and better reflect the forces among rock fragments and the gradual failure process.

Abstract:The static axial compression tests of spot welding square copper tubular components were conducted to study the mechanical property of spot welding components used in shaking table tests. Several components with two kinds of sections were designed. It is found that the components were in elastic phase when they yield, but the change of widthtothickness ratio is different. Based on this study, the finite element analysis models of representative samples was created. The buckling behavior of thin plate with spot wielding boundary condition was studied and the relation between separation distances of welding spots and buckling coefficient was obtained. Besides the compression of components with different widthtothickness ratios and separation distances of welding spots was simulated. The analysis results show the influence of these two parameters on the mechanical property of components.

Abstract:Under extreme weather conditions with strong wind and rainstorm, the rainstorm will directly affect the aerodynamic force on the cooling tower surface, and change the turbulent characteristics of fluctuating wind. However, most traditional researches have only paid attention to the impact force characteristics of wind driven rain on structural surface. In order to solve this problem, aiming at the 210 m world tallest cooling tower in China, the wind field and rain field are simulated respectively by using the continuous model and the discrete phase model based on the computational fluid dynamics (CFD) method, based on which, the action mechanism of the moving speed and trajectory of rain drops in the wind and rain fields are revealed. Besides, the qualitative and quantitative analysis of wind loads, rain loads, raininduced pressure, and equivalent pressure coefficient of 9 different combinations of wind speed and rain intensity are conducted. The surface loads of cooling tower under such extreme conditions can be well predicted based on the equivalent pressure coefficient proposed in this paper.

Abstract:By establishing a cellular rail model based on the spectral element method and combining with Bloch theorem, the vertical decay rate of the rail using the egg fastening system is studied, based on which, the influence of tuned rail damper (TRD) on the vertical decay rate of the rail is analyzed. The results show that the vibration characteristics of the egg fastening system itself causes a new peak of the rail vertical decay rate of around 500 Hz. The influence of the change of the parameters of the iron pad and the rail pad on the vertical decay rate of the rail is mainly reflected at a high frequency of above 500 Hz, and the influence of the change of the parameters of the egg fastening system on the vertical decay rate of the rail is mainly reflected at a middle and low frequency of below 400 Hz.TRD can greatly increase the vertical decay rate of the rail in the vicinity of its working frequency (depending on the mass and stiffness of TRD). The vertical decay rate of rail in the range of 200 to 400 Hz with TRD is more than five times larger than that without TRD. Increasing TRD damping can increase the decay rate of the rail.

Abstract:To develop pad matching for brake disc of SiCp/Al composite, two formulas of metal series and ceramic series were designed. Pads were formed respectively by using the conventional and the microporous forming processes. Sample inertia subscale test, constant speed friction test, full-scale rig test and noise test were conducted. The results show that the average friction coefficient in emergency braking, service braking, and track simulation braking, and the static friction coefficient of J65217c pad by using the microporous forming process can meet the requirements of urban rail vehicle. The wear of J65217c pad is 0.58 cm3?MJ-1, and its noise in service braking is 79.3 to 93.4 dB(A).The maximum temperature of disc in the whole braking process is much lower than 400 ℃.In addition, the fluctuation of friction coefficient and wear of pad can be decreased effectively by reducing metal filler while adding ceramic filler. The wear of pad forming by using the conventional process is slightly lower than that of the pad forming by using the microporous process. Negative slope of friction coefficientspeed curve and porosity guaranteed by the microporous process are beneficial for reducing braking noise. As the braking force increases, the noise increases. The fluctuation of friction coefficient of subscale sample is smaller than that of fullscale pad.

Abstract:In this paper, the SBMundesirable model is used to construct the evaluation model of fuel efficiency in road container transportation, which takes diesel and gasoline as input indicators, road container transportation as expected output indicators, and carbon emissions as undesired output indicators. Afterwards, the fuel efficiency evaluation of highway container transportation in Jiangsu Province from 2003 to 2014 is conducted. The results manifest that the fuel efficiency in southern Jiangsu is the highest, followed by that in northern Jiangsu, and central Jiangsu. The comprehensive fuel efficiency value is generally low, which shows a downward trend of fluctuation, from 0.643 5 in 2003 to 0.611 6 in 2014. The change characteristics of technical efficiency and comprehensive efficiency are basically the same, and the efficiency values show a declining state, while the scale efficiency shows a rising trend. Generally speaking, the scale efficiency is greater than the technical efficiency and greater than comprehensive efficiency. The correlation coefficients of technical efficiency, scale efficiency and comprehensive efficiency are 0.962 and 0.841, respectively, indicating that the main factor for low comprehensive efficiency is its low technical efficiency. Finally, from technical and policy aspects, this paper puts forward some policy suggestions to improve the fuel efficiency of highway container transportation, so as to provide reference for highway transportation energy management.

Abstract:The nutrients are usually leaching from the bioretention system and reducing the reusable value of stormwater for landscape water supplement. In this paper, wood chips were used as the organic component of the bioretention system to reduce the medium nutrient content and to increase the nitrogen removal capacity of the system. The pollutant concentrations in the effluent, the factors affecting the effluent quality, and the nutrients reduction impact on plant growth were analyzed. The results show that the mass concentrations of nitrogen (N) and phosphorus (P) in the effluent are much lower than that of the wastewater reclamation, indicating that both N and P are effectively controlled. The amount of wood chips in the medium is decreased in the continuous operation for two years, while the average mass concentrations of chemical oxygen demand (COD) and total phosphorus (TP) in the effluent are decreased to 10.88 and 0.08 mg?L-1, respectively. The mass concentration of total nitrogen (TN) does not change significantly with the average value of 2.72 mg?L-1. Using wood chips as the medium organic component can stably provide the carbon source for the denitrification, while reducing the organic matter and nutrients concentration in the effluent. The effluent of the woodchip bioretention system can provide high quality supplementary water for urban rivers.

Abstract:A novel water distribution network (WDN) analysis model, segmentvalve diagram with flow directions (SVFD), is proposed to elaborate the reliability of WDNs in case of accident. By transforming a WDN valve topology model into a directed graph and marking directions of water flowing through valves with directed edges, this model can more accurately determine the valves to be closed when a pipe burst occurs, and is conducive to obtaining the really complete outage area. This paper takes advantage of SVFD to evaluate topological reliability of WDNs, and designs 5 new evaluation indicators oriented to accident impact, isolation difficulty and emergency disposal time. Reliability analysis of WDNs in 3 Chinese cities is conducted with these indicators, which shows that compared with the traditional classic indicators based on the segmentvalve diagram, the improved indicators can reflect the actual impact and disposing difficulty of pipe network accidents more accurately and clearly.

Abstract:In this paper, the mineralization effects of ureolytic type microorganism were employed in the surface treatment of concrete after carbonation. The capillary water absorption, resistance to water permeation, and rapid chloride permeation (RCP) of concrete were tested after treatment. The contact angle of the surfaces was measured. The morphology and composition of the deposits were comprehensively studied. The results show that both carbonation and microbial surface treatment can increase the resistance to permeability while reducing the water absorption of concrete. Large calcite crystals, which tightly adhered to the concrete surfaces, are formed by microbial treatment. Carbonation has no impact on the crystalline and morphology of microbial precipitates. However, after microbial surface treatment, different effects are observed on the water absorption and permeation of concrete with or without carbonation. When microbial surface treatment is performed after carbonation, the range of further reduction in terms of water absorption coefficient is higher compared with the reduction by the treatment on uncarbonated concrete. The main reason for this phenomenon is that the degree of hydrophilicity of concrete after carbonation decreases after microbial surface treatment.

Abstract:Two representative kinds of bubble structure modifying agents were selected to study the effect of different types of bubble structure modifying agent on the fluidity and compressive strength of the airentrained mortar. The mechanism of the bubble structure modifying agent on the fluidity and compressive strength of the airentrained mortar was researched by testing pore structure parameters of the hardened airentrained mortar with bubble structure modifying agent and the surface tension of the liquid. The results show that the viscosity modifying agent, cyclodextrin (βCD), can delay the airentraining process by increasing the liquidphase viscosity of the mortar, so that the bubbles (pores) in the mortar can be refined, the porosity of air void size ranging from 10 μm to 20 μm can be raised, and the fluidity and compressive strength of the mortar can be increased. The antifoaming agent, siloxane polyether copolymer (PSPEO), can replace the airentraining agent molecules on the surface of the bubbles film and reduce the local surface tension. The big bubbles are refined into small bubbles with lowdosage PSPEO, while the strength of the gasliquid interface film is reduced, bubbles cannot exist stably with highdosage PSPEO and the total porosity is lowered. Therefore, the fluidity of the mortar first increases and then decreases, and the compressive strength continuously increases.

Abstract:The posture risk of each task is calculated by using rapid entire body assessment (REBA). Accumulated fatigue of station (AFS) is proposed for cumulative fatigue of all tasks at one station considering time and task posture. In order to ensure least stations and balance of fatigue, a multiobjective optimization model is constructed to minimize the number of stations and AFS with precedence relationship constraints and task assignment restrictions. The multiobjective particle swarm optimization algorithm coded by precedence is designed. The rationality and effectiveness of proposed method is proved by a real case.

Abstract:There are too many variables in the optimization design of the truss girder structure with bulge formed joint. Besides, the scale of the optimization is large. In addition, the calculation is complex and the convergence is not suitable if the integral monolayer optimization strategy is adopted. In order to solve these problems, a hierarchical cooperative optimization strategy based on subspace and coupling constraints has been proposed. The design space is divided into three subspaces， which are the whole layer, the section layer, and the surface optimization layer. The upper layer provides the optimization results for the lower layer while the lower layer provides the coupling constraint for the upper layer. The result shows that the optimization method can get good results and has some engineering significance.

Abstract:Based on k-means and support vector machine (SVM) algorithms, an online self-adaptive fault diagnosis method for automotive fuel cell system (FCS) is proposed. By continuously acquiring cell voltages and using k-means clustering to improve the original SVM classifier model, this method can achieve online self-adaption of the classifier. The experimental data from published papers were used to verify and analyze the results. The results show that the proposed method can effectively adjust the fault classifier online to detect the fault after changing the FCS system characteristics.

Abstract:The standard kε-turbulence model and the two phase flow Eulerian model are used to simulate the refrigerant distributions in the heads of parallel-flow evaporators, and the experimental results in literature is used to validate the numerical method. Then, the comparison of distributions between base line structure and the structure with perforated tube in heads is conducted and the reason behind the performance improvement of the structure with perforated tube is revealed. The comparison of flow distribution in heads with perforated tubes in the open ratio ranging from 0.11 to 1.00 indicates that the uniformity of flow distribution decreases at first and then increases, after which it worsens with the further increase of open ratio. The matching issue of expansion valve with refrigerant systems should be concerned under the condition of small open ratio of perforated tubes.

Abstract:A comparative assessment of the external and internal insulation for an intermittent air-conditioned building was numerically performed. The energy consumed for cooling was used to evaluate the insulation configurations of exterior walls. There was concern about the effect of the periods that the building was occupied, the air conditioner (AC) operation modes and the power of the heat source in this study. The results show that the external insulation configuration have a better thermal performance compared to the internal insulation configuration, when the building was occupied at daytime. When the building was occupied at night, the internal insulation configuration have a better thermal performance if the AC runs continuously. If the cold storage of the building was applied for energy conservation, the power of the heat source should be considered to determine the insulation configuration. The determination of the insulation configuration of the exterior walls should take those three factors into consideration, including the occupancy time of the building, the AC operation modes, and the power of the heat source.

Abstract:In order to improve the accuracy and robustness of the saliency detection algorithm, this paper proposed a multiscale image saliency detection method. First, the smoothing algorithm was adopted to filter out the noise characteristics in the image. Then, the multiscale representation of an image was performed and saliency maps were computed at different scales. Finally, according to the conditional random field theory, the saliency detection results at different scales were weighted together to get the final results. Extensive experiments in which the proposed method was compared with 9 existing stateoftheart methods on five benchmark data sets, ECSSD and MSRA10K, show that the proposed method performs better in terms of various evaluation metrics.

Abstract:A novel method is proposed in this paper to recognize the container code from the images with large perspective deformation. First, the images are rectified by perspective transformation. Then, 26 capitalized English characters and 10 Arabic numerals are located and recognized based on the deep convolution neural network model. Finally, container codes are recognized from the candidate character set by cascade decision rules based on the priori knowledge of container code. The proposed method is verified by 1035 container images taken in Chongqing Port. The result shows that the accuracy of container code recognition reaches 97%, and the speed based on NVIDIA GeForce GTX1080 GPU is 2 to 5 frames/sec.

Abstract:A relaxation modulus-based matrix splitting iteration method is proposed for solving a class of nonlinear complementarity problems. The convergence theory is established when the system matrix is H+and the choice of relaxation parameters is given. Numerical examples show that the proposed methods are efficient and can accelerate the convergence performance of the modulus-based matrix splitting method with less iteration steps and CPU time.

Abstract:For graphs G and H, Ramsey number r(G,H) is the smallest integer r such that every 2coloring of Kr contains either a red copy of G or a blue copy of H. Star critical Ramsey number r*(G,H) is the smallest integer n such that every 2coloring of KrK1,r-1-n contains either a red copy of G or a blue copy of H. Under the inspiration of star critical Ramsey number, complete critical Ramsey number rK(G,H) is the largest integer n such that every 2coloring of KrKn contains either a red copy of G or a blue copy of H. In this paper, rK(Wn,Ka) and rK(Cn,K3) are determined. Wn=K1+Cn-1 is a wheel of size n.