The dynamic mesh method that could simulate the actual moving of train was used to calculate the aerodynamic coefficients of train on bridge with wind barriers of various heights, and the static pressure distributions around the train body and velocity magnitude distributions were analyzed, the results computed by dynamic mesh method were compared with that computed by traditional static mesh method. The results show that the aerodynamic coefficients of train and flow field characteristics computed by the two methods agree well under the configuration without wind barriers. However, there is considerable difference between the results computed by the two methods with the installation of wind barriers. It is found that the dynamic mesh method is more reasonable to simulate the aerodynamic coefficients of train with wind barriers by analysis of the contour of static pressure distributions and velocity magnitude distributions. The wind barriers effectively decrease the positive pressure on windward train body and negative pressure on train roof, mainly reduce the side force coefficient, lift force coefficient, rolling moment coefficient. Therefore, the aerodynamic performance of train on bridge under crosswind is improved.

The train-bridge aerodynamic spatial model was established, and the aerodynamic coefficients of train on bridge were calculated accordingly. The method for acquiring train critical speed under crosswind was derived by the statics, the displacement bring from springs, aerodynamic force, lateral and vertical vibrational inertia force, centrifugal force and gravitational force were considered in the derivation. The results show that the head trains aerodynamic coefficient will reach peak value around wind incidence angle, the rear trains aerodynamic coefficient varies constantly with incidence angle. Side force and lift force coefficients will get maximums when train attack angle , overturning moment coefficient absolute get maximum at . For trains overturning stability, crosswind from the inner of curve blows to the head train running on the windward line of bridge is the most dangerous situation.

The fluctuating wind field is simulated for digital by using the AR method. A three-dimension finite element model of high-pier long-span rigid frame bridge is presented in this paper. Based on this model, the gust-induced static response of the bridge under the longest cantilevered construction stage is computed. By comparing with those of two similar span rigid frame bridges with low piers, the gust-induced response characteristics of the internal force under the bottom of the piers of the high-pier long-span bridges are investigated, which is helpful for the safe design of bridges. The buffeting responses of the bridge under the longest cantilevered construction stage are also calculated in the time domain, taking account of the longitudinal and vertical turbulence action. Through the spectral analysis of the response, the comfort index of Diekemann is obtained. The effects of buffeting response on the workers’ safety under the most unfavorable construction stage are discussed.

Effects of different electron donors (acetate and hydrogen), acetate and perchlorate concentrations on microbial perchlorate reduction in groundwater were studied. The results showed that acetate and hydrogen addition as an electron donor can significantly improve perchlorate removal efficiency while a longer period was observed for hydrogen (15 d) than for acetate (8 d). The optical ratio of electron donor (acetate)-to-electron acceptor (perchlorate) was approximately 1.65 mg COD mg perchlorate-1. The highest specific reduction rate of perchlorate was achieved at the acetate-to-perchlorate ratio of 3.80 mg COD mg perchlorate-1. The perchlorate reduction rates corresponded well to the theoretical values calculated by the Monod equation and the parameters of Ks and Vm were determined to be 15.6 mg L-1 and 0.26 d-1, respectively.