Abstract:Against large-span beam bridge structure and its application characteristics, a new type hybrid-beam bridge, consisted of prestressed concrete beam and steel-concrete composite girder in longitudinal, is proposed. The advantages of this new hybrid beam comparing to other forms of beam bridge are analyzed and compared. Expression for calculating the mechanical behavior of this new type bridge is derived and the key factors that affect the mechanical behavior of the new hybrid beam bridge are summarized. The correlation between the length ratio of side span and mid span and the position of combined segment in the mid span is obtained. The mechanical properties of an actual project are calculated by the method proposed here and the finite element method respectively. Comparison on the calculation results tests that the deduced method in this paper is accurate highly and it can be used in the computing and analyzing the structural behavior of this new type mixed-beam bridge.

Abstract:One beam subjected to room temperature and 7 beams subjected to high temperature were tested. Three sides of the beams were subjected to ISO834 standard heating curves for 2 hours, and they were tested after cooled. The effect of shear span ratio, sectional dimension and position subjected to fire were studied. The results show that after fire, shear bearing capacity of the concrete beams decreases, shearing stiffness of the member degrades, and ultimate deformation increases. The results also show that the shear bearing capacity decreases as the shear span ratio increases, the high temperature has more influence on compression zone, and depth of section of the beam with three sides subjected to fire has the same effect to shear performance as in room temperature. A finite element method is suggested to calculate the shear bearing capacity of concrete beams after fire, which has accepted accuracy.

Abstract:On the basis of the pseudo-static tests of reinforced concrete (RC) and steel fiber reinforced concrete (SFRC) pier specimens under low reversed cyclic loading, the nonlinear finite element models of concrete piers under cyclic loading were established using analytical method of fiber model. In the modeling, the concrete material model with the affect of steel fiber and steel material model considering bond-slip effect were adopted. The influences of steel fiber volume fraction, stirrup ratio and the height of SFRC region on seismic capacity of the piers were obtained by the numerical analysis. Several aspects about seismic performance of the models, including hysteretic characteristics, skeleton curves and ductility, were discussed by the numerical simulation method. The numerical results were compared with the test results. The results show that the simulation results of seismic response are basically identical with the pseudo-static test results; part of the stirrups’ role of seismic resistance can be substituted by the addition of steel fibers, and the seismic capacity of concrete piers is improved with the increase of steel fiber content in a certain range; similar seismic capacity can be sustained when the piers are constructed with local or wholly application of SFRC.

Abstract:Two full scale specimens of orthotropic steel decks with on-site bolt-welded U-rib connection detailing were designed and fabricated, and then the fatigue tests were conducted. A FE model of bolt-welded joints for the orthotropic steel bridge decks was proposed. The FE analysis showed that the longitudinal stresses in the inner connection plate were higher than those in the outer connection plate, and the stresses were influenced by the out of plane bending in the bolted U-rib joints. Stress distribution along the axial direction of the connection plate appeared a saddle-like shape. The stresses in the center region were higher than those in the end, which led to the fact that fatigue cracks appeared earlier in the center region of the inner connection plate in the both specimens. It is suggested that the fatigue strength of bolted U-ribs joint in the orthotropic steel decks be evaluated based on the fatigue design curve of category 71 in EUROCODE or the fatigue design curve of category IX in the Code for Design of Steel Railway Bridges. A parameter study base on FE analysis was further developed to optimize dimensions of the bolt connection plates and to improve the fatigue performance of the steel bridge decks.

Abstract:An index system for evaluation of the health status of cable stayed bridge is presented based on a set of dissimilarity measures (abbr. DM) of cable force of grouped cables. The thresholds of DM derived from the serviceability limit state and ultimate limit state of the bridge are defined by the combination of FEM and influence matrixes method. The Monte-Carlo method is used to obtain the rational values of these thresholds. By comparing these indices with its thresholds, the discrimination on holistic health status of cable stayed bridge can be done easily and explicably. By using the 8 years historical data of cable forces investigated from an real cable stayed bridge, the proposed method are applied to evaluate the health status of an real cable stayed bridge. The results show the validity of proposed methods.

Abstract:The system of linear equations can be given to describe the flow conservation in the road network based on the turning ratios at intersection. The coefficient matrix of the system describes the relationship of the flow direction among links. By the point-arc exchanging from the traditional road network topology, a directed graph can be used to represent the flow-direction relationship, with the coefficient matrix of the flow conservation equations as its adjacent matrix. The coefficient matrix describes a directed graph composed by several directed-circle groups. According to the performance of directed-circle group and Taussky’s theorem of nonsingular matrix judgment, the conclusion of the rank of the coefficient matrix is equal to the number of the rows is given. Based on this conclusion, the fact that the close-ring sensor location design can give the unique link flow solution over the network is proven. Finally, the fact that the design of the sensor location based on the turning ratios at intersection is not unique is discussed.

Abstract:The mechanical properties of the steel deck pavement on Chongqi Bridge were carried out using a three stage mechanical analysis method. Based on the results of the mechanical analysis and the research conclusion of the main steel deck pavement cases, dual layer epoxy concrete steel deck pavement was designed. The pavement performance such as moisture resistance property, high and low temperature property, salt spray resistance property, mechanical property and fatigue property of epoxy asphalt concrete had been researched. The results show that the rich-asphalt epoxy asphalt mixture can satisfy the requirements of Chongqi Bridge deck pavement better than common epoxy asphalt mixture.

Abstract:On the basis of the summary of advantages and disadvantages of the main track types used in newly built high-speed railway in China include CRTSⅠslab, CRTSⅡslab and double-block ballastless track, CRTSⅢ slab ballastless track has been proposed. CRTSⅢ slab ballastless track on roadbed have two design schemes which are unit style and longitudinal continued style. In this paper, longitudinal-transverse-vertical spatial coupled model is established, and the mechanical characteristics of two design schemes under the action of temperature load, vehicle load, concrete shrinkage and foundation settlement deformation are calculated and analyzed. Analysis results show that for the severe cold area, considering the influence of temperature load and maintainability of track, the unit style structure is suggested.

Abstract:Six animo acids and ammonium nitrate were tested to study the effects of nitrogen sourceon the growth of cell-bound biodemulsifying strain of Alcaligenes sp. S-XJ-1. The utilization process of nitrogen source were studied when glutamic and ammonium nitrate was separately used as nitrogen source. The growth model and nitrogen utilization model of S-XJ-1 were built as well. The results showed that S-XJ-1 preferred to use organic nitrogen when organic nitrogen and ammonium nitrogen coexisted in the substrate, and ammonium nitrogen was preferred than nitrate nitrogen.The results also showed that the yield and property of biodemulsifying bacteria was significantly affected by the variety of nitrogen source,and glutamic was testified to be the best nitrogen source for S-XJ-1 among the six amino acids. When glutamic was used as nitrogen source, S-XJ-1 exhibited higher maximum specific microbial incremental rate(µm), higher utilization ratio of nitrogen source(YP/S) and lower energy cost.

Abstract:The 10 um plankton sampling network was used to survey the microfauna in the outflow of granular active carbon (GAC) filter in A plant, which showed that the dominant species were Rotifera, Nematode, Oligochaeta and Crustacea. When the thickness of quartz sand filter layer was 40 or 50 cm, the grain size was 0.3-0.5mm and the flow rate was 10-12 m•h-1, more than 50% of the large metazoan, such as rotifera, crustacean, and oligochaeta, could be intercepted, but few nematode could be intercepted. It was suggested that the 10 um microstrainer should be added after the chlorine chamber, and this enhanced filtration could reduce the risk of microfauna leakage by one grade and the work cycle could reach 96 h.

Abstract:Comprehensive technical and economic evaluations were performed for eight kinds of domestic sewage treatment processes commonly used in wastewater treatment plants in China, including conventional aeration, hydrolysis – aerobic process, AB method, A/O method, A2/O method, alternating type oxidation ditch, integrated oxidation ditch and SBR. Three major categories of total 13 evaluation factors, including treatment effect, economic aspect and project implementation were analyzed and compared through a sampling investigation. A multi-factor evaluation system was established and the factor weights were set. Evaluations were performed with fuzzy mathematics method and the results were compared with those of expert evaluations. Research results showed that A2/O, A/O and oxidation ditch were more applicable to the sewage treatment plants in large or medium-sized cities, among which A2/O was particularly prominent.

Abstract:Under hot and humid climate, it is difficult to inhabit the surface condensation in underground space with the combined system of mechanical exhaust and natural air supply. This situation results from the low surface convection and large thermal inertia of the soil. Meanwhile, such ventilation system is not conducive to reduce the exhaust pollution in such underground space as garage. This study tries to resolve the serious condensation problems of a large underground garage with the deeply spatial pattern in Shanghai, which is ventilated by the dominant effect of uniformly distributed exhausts. Test and analysis of surface condensation are carried out under the originally equipped system. An inductive air-jet system, taking into account the attached effect along wall and impinging effect on the floor, is presented. It is applied to intensify the air velocity and turbulent level near the surface, and thus to increase the surface heat transfer and temperature. It is confirmed that the surface condensation is significantly reduced under hot and humid season through the inductive air jets. Meanwhile, the improved system also reduces the accumulation of concentration of CO gaseous pollution at the breathing zone in the garage.

Abstract:The current Chinese code Specifications for design of ventilation and lighting in highway tunnel lists the admissible CO mass concentration limits for tunnel and varies from international standards on both values and principles. Two typical types of longitudinal ventilation tunnel are longitudinal ventilation tunnel with jet fan(s) and longitudinal ventilation tunnel with jet fan(s) and vertical shaft(s). Difference form of Coburn-Forster-Kane equation (CFK equation) was introduced to calculate the CO mass concentration limits for those two types of longitudinal ventilation tunnel and a fitting equation for predicting permissible CO mass concentration limits is presented and is applicabe to both types of tunnel. The results show that the CO mass concentration limit values for long length longitudinal ventilation tunnel should be lower.

Abstract:An ordered-specimen cluster analysis based optimization method is proposed for the widely scattered and utterly disordered body electrical devices connection with local networks. First, cCompletely distributed body electrical system with hierarchical subnet architecture is proposeddescribed. Through electrical device reduced-dimension ordering, the optimization problem is converted to the ordered-specimen optimized partitioncluster with limited -capacity problem under consideration of network schedulable condition. Model’s solver algorithm is also proposed using the global search method. Finally, tThe optimization method is used during the development of the completely distributed body electrical system on one prototype vehicle and is proved to be feasible.

Abstract:In order to obtain body loading spectrum of high accuracy in fatigue prediction, a procedure of the spindle displacement back-calculation to acquire body loading spectrum is presented, with a case study of a light-duty bus. Firstly, road loads in the providing ground is collected by arrangement of some sensors. Secondly, the multi-body dynamic simulation model is established with a satisfied accuracy. Finally, virtual iteration is introduced in theory, and applied to cascade body loads from the wheel hubs. The conclusion can be drawn that the simulation signals obtained from the proposed method accords with the experimental data, and thus the extract load information of the body interface points can be utilized to evaluate the fatigue life time.

Abstract:In order to study moving-belt system’s effect on measurement of lift force, no load test of moving-belt system was carried out by wind tunnel test and numerical simulation and their results were compared. The agreement of lift force results from the wind tunnel test and numerical simulation indicates that the test results and numerical results can be validated each other, and the numerical simulation is feasible. The relationship between moving-belt system and vehicle body shape was studied by using this way. The result shows that for different vehicles, the moving-belt system’s effect on measurement of lift force is almost the same. The △CL is about 0.040 . We can use these relationships to revise the test result of lift force.

Abstract:The stick-slip behaviors of wheel-rail between LM, LMA, S1002, XP55 wheel profiles and CHN60 rail in static rolling contact were analyzed using the rolling contact theory of three-dimensional elastic bodies with non-Hertz form and numerical program of CONTACT. The numerical results indicate that the stick-slip characteristics of wheel-rail between LM, LMA, S1002, XP55 wheel profiles and CHN60 rail are different. The wheel profile has obvious effect on area of contact zone, stick-slip distributing amd friction work wheel-rail. The stick-slip characteristic between LMA wheel profile and CHN60 rail is better and the areas of contact zone and stick zone are larger. The stick-slip behaviors between S1002 wheel profile and CHN60 rail is better than that of XP55 wheel profile.

Abstract:The purpose of this study is to find the ultimate strategy to solve the cold start problem when fuel cell vehicles or fuel cell backup power stations in the low-temperature environment for long-term after its shutdown, this paper uses hydrogen catalytic combustion auxiliary heating cold start strategy, which puts hydrogen and air in the external catalytic reactor for catalytic combustion, and then puts the hot mixed gas into a fuel cell cathode flow field and water flow field. Subsequently, a auxiliary PEMFC strategy cold start test platform has been established based on catalytic combustion. Finally, the airspeed, hydrogen concentration and other conditions affect have been researched. Finding that increasing the hydrogen concentration and airspeed of the reaction mixture can shorten fuel cell start time. When the space velocity is 3L/min, hydrogen volume concentration is 4%, the fuel cell internal temperature can rise to zero degrees centigrade from minus ten degrees centigrade within 600 seconds.

Abstract:A test room with low illuminance was set up to research volunteer’ behavior on lighting and shading when they arrive. Consistence was reached by comparison between real behavior and default behavior during questionnaire period. Results show: 80% occupants open the rolling to improve inside lighting environment; 16% occupants rely only on artificial lighting and 25% occupants use both artificial lighting and rolling. Main reasons for the behavior are found to be the preference to day-lighting, natural ventilation, wide vision, and life habit. Experimental results also show that the location of the switch has big effect on the choice of the switch, which means that people prefer to the easily-reached switches. A revised control logic for building energy performance simulation is suggested, which will be more close to the real scenario.

Abstract:The nonlinear differential equation for aerosol concentration of the particle-loaded porous fibrous media was established based on the transport equation, N-S equation in the applications for Newton viscous fluid. The general governing equation for aerosol concentration with the packing density of the particle-loaded porous fibrous media was calculated by the mass deposition of dust or aerosol particle. In addition, laboratory experiment was carried out to study the close correlation among the classic dimensionless parameters and their influence on the filtration efficiency of particle-loaded fibers. The empirical formulas about the dynamic filtration efficiency were developed through nonlinear regression. The results of experiment showed that the air flow lied in the Stokes region and in the laminar flow as Reynolds number is less than 1. The calculated interception parameter R was around 0.086~0.559. However, the fitted empirical formulas about the dynamic filtration efficiency in this paper were only applied to the case where Stokes number is less than 1.

Abstract:Using triangulation to generate contours is time-consuming and it needs lots of post-processing work. This paper presents a new contour generation method based on Rapid Prototyping technology. It stratifies point clouds by adopting Rapid Prototyping technology. The feature points are derived by calculated the weighted coordinates of points of the upper and lower layers. The feature points are projected onto a plane and converted to grid image. The image outline is extracted and edge tracking is performed by the line segment of the grid. Finally B-spline fitting is used to generate the contours. Experiment has shown that the proposed method not only generates contour lines with good quality but also improve the efficiency of operations by reducing the process of building a triangular network.

Abstract:This paper is devoted to solving a constrained linear-quadratic (LQ) singular optimal control problem. Differing from the traditional way, it avoids adding a small perturbation for an approximation process. The optimal control of this problem is given explicitly with the co-state variable by the Pontryagin maximum principle and the canonical backward differential flow.

Abstract:Separating butanol from fermentation broth is an urgent problem to be solved in its industrialization and application. We compared different separation techniques which can be coupled with fermentation process according to their separation performance and economic efficiency and pointed out the advantages of pervaporation. Then we reviewed the recent advances in pervaporation membrane materials used in the separation of biobutanol. which focused on the separation performance of the polymer membranes and the corresponding modified polymer membranes, such as PDMS, PTMSP and their modification. Moreover, we also summarized the performance of the supported liquid membranes used in the separation of biobutanol and their stability issues. The effects of some other compositions in the fermentation broth, such as solvent, intermediate, and biomacromolecule, on the separation performance were analyzed as well. At last, future prospects of the pervaporation membrane for biobutanol were proposed.

Abstract:In this paper, under the reduced form framework, a pricing model for loan-only credit default swap (LCDS) with negative correlation between prepayment and default is established. Under reduced framework, by one factor inverse CIR model, we obtain a closed form pricing formula. Using this formula, a calculation scheme for credit value adjustment (CVA) for LCDS is given, where the counterparty risk of the LCDS is considered. Moreover, a wrong way risk related issue is discussed. The research conducted in this article indicates that the price of an LCDS contract with counterparty credit risk (CCR) is lower than one without CCR, and CVA increases with the termination of the LCDS, interest rate and the correlation between the reference loan and the counterparty. The spread for an LCDS with CCR is lower than that of a normal LCDS. If the reference loan is negatively correlated with the counterparty, CVA decreases with the absolute value of the correlation coefficient.

Abstract:In view of the needs of e-commerce website for recommendation system, user interest is divided into long-term interest and short-term interest, furthermore, based on long-term interest and short-term interest, a way to describe user’s preferences is proposed. Utilizing the data from the web server database, using unsupervised learning, user’s registration information can be fully mined to abstract user’s long-term interest. Based on vector mapping, both the records data and content data on the server log is analyzed to abstract user’s short-term interest. Moreover, the rough profile presenting user’s preferences can be modified by dealing with user’s feedback, and that makes updating user’s preferences profile possible. Case analysis illustrates to a certain extent this method is reasonable and feasible.