Nano-CeO2 doping mitigates the surface antimony enrichment and promotes the complete oxidation of antimony, while cerium ion doping aggravates these things.
This article describes the research work relating to the assessment and control of human-induced vibration of an unusual curved cable-stayed bridge with separate road and pedestrian decks. Dynamic simulations of human-induced vibration were performed with a mode-by-mode approach, and the results showed that a total of eight lateral and vertical modes of the bridge may suffer from excessive vibrations at the design crowd density. A hybrid control scheme was developed for control of human-induced vibration, which consists of steel braces fitted between the road bridge deck and the pedestrian deck to improve structural stiffness and eddy current tuned mass dampers to enhance damping ratios of lively modes. The modal properties of the bridge with steel braces were experimentally obtained by dynamic tests and used for parameter tuning of mass dampers. The performance of the hybrid control strategy was evaluated by group tests of up to 400 pedestrians. It is shown that the critical number of pedestrians...
The Sb-doped SnO2 electrode is modified by TiN nanoparticles and has higher stability and significantly enhanced electrochemical decolorization activity.
Vortex-induced vibration (VIV) has been occasionally observed on a few long-span steel box-girder suspension bridges. The underlying mechanism of VIV is very complicated and reliable theoretical methods for prediction of VIV have not been established yet. Structural health monitoring (SHM) technology can provide a large amount of data for further understanding of VIV. Automatic identification of VIV events from massive, continuous long-term monitoring data is a non-trivial task. In this study, a method based on the random decrement technique (RDT) is proposed to identify the VIV response automatically from the massive acceleration response without manual intervention. The raw acceleration data is first processed by RDT and it is found that the RDT-processed data show different characteristics for the VIV response and conventional random response. A threshold based on the coefficient of variation (COV) of peak values of processed data is defined to distinguish between the two kinds of responses. Both random vibration and VIV for a three-DOF (degree-of-freedom) mass-spring-damper system are obtained by numerical simulation to verify the proposed method. The method is finally applied to the Xihoumen suspension bridge for identifying VIV response from three-month monitoring data. It is shown that the proposed method performs comparably with the method of novelty detection. A total of 60 VIV events have been successfully identified. Vortex-induced vibrations for the second to ninth vertical modes with modal frequency within 0.1~0.5 Hz occurs at wind velocity 5–18 m/s, with wind direction nearly perpendicular to bridge axis. Amplitude of VIV generally decreases with increase of wind turbulence intensity; however, noticeable VIV amplitude are still observed for turbulence intensity up to 13% in some cases.