Applied Mechanics and Materials Vols. 71-78

Abstract: As the data of aluminum alloy corrosion is increasing, the experimental data and results of corrosion damage are collected in this paper, thus the corrosion damage draft at different corrosion time and temperature are obtained. The Oracle 10g is introduced as basic database to design the image database of aluminum alloy corrosion damage. The front makes use of the asp.net to realize the web information displaying, meanwhile the corrosion damage database of aluminum alloy is realized the image data storage and retrieval. This provides a great convenience for researchers to utilize corrosion damage data. At the same time, the database stores the image data effectively, which improves the computer memory usage.

Abstract: The structure characteristic of prestressed concrete(PC) composite box-girder with corrugated steel webs is introduced, and the advantage is shown compared to PC girder bridge. Design of PC composite girder bridge with corrugated steel webs is introduced, contents including corrugated steel webs, shear connector, etc. The domestic application and development of PC composite box-girder bridge with corrugated steel web is reviewed, and part of the typical bridges combined with corrugated steel web PC box-girder are listed. On behalf of PC composite box-girder bridge with corrugated steel web, Shandong Juancheng Yellow River Bridge is introduced in detail. At last, the future of this type of bridge is prospected.

Abstract: The foam phosphogypsum with low bulk density has been prepared. The influence of retarder content and water-cement ratio on the setting time and strength of phosphogypsum paste, and the effect of water-reducing agent and bulk density on the strength of foam phosphogypsum have been studied. The mechanical behavior and thermal conductivity of the foam phosphogypsum have also been researched. Besides, the failure curve of the as-prepared foam is plastic-like which is different from the brittle failure of normal foam concrete. And the high energy absorption effect of the samples has also been found.

Abstract: Aiming at the reliability of Q345 steel material impacted on high temperature and dynamic shock load, its mechanical properties are studied in this paper based on the split Hopkinson pressure bar, the SHPB test facility is introduced in detail. And the stress-strain curves of Q345 steel are obtained in the special industrial condition. The flow stress decreases clearly in pace with the increasing of temperature, which provides credible technique evidences for the maintenance and health appraising of the structure.

Abstract: This work aims preparation cheaper and high performance reticulate porous ceramic (RPC) for organism carrier. The RPC were made from clay by polymeric foam replication process. The X-ray diffraction (XRD) phase analysis indicates that the RPC mainly consist of mullite when sintered at 1350°C. The surface status of different component RPC was observed under scanning electron microscopy (SEM). The bio-film properties of different component and different pore size RPC were evaluated by the removal rates of COD_Cr and NH₃-N. The results show that the RPC had high effectiveness for microorganisms’ adsorption, the removal rates of COD_Cr and NH₃-N are all reach to 90%, and the bio-film effect is related to porosity, pore size and surface status of the RPC, but the porosity and pore size play more important role than the surface status of these carriers in bio-film process, the RPC carriers with more porosity and suitable pore size achieve better sewage treatment effect.

Abstract: This experiment is performed to investigate heat transfer characteristics with the PCM microcapsule slurry in a solid phase state at a horizontal rectangular enclosure heating from below and cooling from top. Some important parameters are taken into account such as the mass concentration of the PCM, the temperature difference between heating plate and cooling plate, Nusselt number Nu, Rayleigh number Ra and the aspect ratio (width/height) of the horizontal rectangular enclosure. Experiment is done under the thermal steady condition in the PCM microcapsule slurry. Heat transfer coefficient is measured under various temperature differences in PCM mass concentrations of 10% and 20%. And relationship with Nusselt number Nu and Rayleigh number Ra is summarized to various heights H or the aspect ratio (width/height) Ar of enclosure.

Abstract: The article mainly discusses the application situation on the solar energy wood drying in China, and summarizes its advantages and problems in the real application. Because solar energy is low in thermal density, intermittent, and it is affected by weather, these have very big limitation to use solar energy in the actual production process. Based on these, it is introduced that the advantages of thermal energy storage technology in wood drying process of solar energy, the main application modes and the actual application status. It summarizes the major thermal energy storage materials and their basic characteristics, discusses the application prospect and the importance on the latent heat storage technology in wood drying.

Abstract: Many villages are located along highways in China, especially in two-way highways, which influence the drivers’ maneuver, then the traffic safety. Systematic experiments are designed to collect speed information about through vehicles. The video method is selected and the experimental sites include common segments, intersection segments, segments with villages are situated along both sides. Then the vehicle speed characteristic of different highway segment types are analyzed and compared. Basing on the speed characteristic, the safety influencing extent is also defined.

Abstract: During the measurement of a BOTDR system, it is significant to keep the extinction ratio of probe pulse uniform if constant sensing performance is desired. However the bias point of an electro-optic modulator (EOM) may slowly changes due to many external factors. Thus the variable bias point of the EOM must be stabilized. In this paper, a novel and simplified stabilization technique based on digital signal processor and step-by-step tracking algorithm is proposed. Contrast experiments with and without the stabilization are performed. The experimental results show that our method can lock the EOM’s bias point quite well and improve the sensing system’s performance obviously.

Abstract: Vacuum glazing is a very choice in building energy efficiency. Therefore, it is necessary to study on evacuating process of vacuum glazing. Based on fundamental pumping equation of vacuum technique and simplified the existing pumping system for vacuum glazing, a mathematical model, which is described evacuating process of vacuum glazing, is established. An exact mathematical solution is obtained by solving the model. According to the solution, an example from a practical evacuating system is solved and analyzed, and two conclusions are summed up as follows: First, the evacuating time needed for vacuum glazing is mainly depended on the flow conductance at vacuum glazing’s bleeding point; Secondly, the ultimate pressure of vacuum chamber should two orders of magnitude lower than the required pressure in the vacuum glazing. Above model, solution and conclusions have a certain guiding significance in the actual production of vacuum glazing.