Advanced Materials Research Vols. 168-170

Abstract: A secondary oxidation and expansion of graphite process resulted in a specific surface area enhanced material, which could be used in methylene blue (MB) adsorption in industry, due to the low running cost and mass production. The morphology of the samples was investigated using scanning electron microscopy, and the structures vary from the expansion level. It was found that with a pH value about 9, the sample exhibited better adsorption property toward MB after re-expansion. The adsorption capability of MB adsorbed on unit mass of the secondary expanded graphite turned out to be 120mg/g. The considerable adsorption capability could be further enhanced through a multiple expansion process.

Abstract: In the past few years, recycled asphalt has been used successfully in asphalt concrete pavement in China. However, the performance of recycled asphalt does not know. The objective this study is analyses the performance of asphalt which using vacuum rotating reclaim. Lanlian No.70 petroleum asphalt was put into pressure aging vessel after one hour, five hours, ten hours, fifteen hours, and twenty hours of aging. Afterwards, the different aging degree asphalt was dissolved by trichloroethylene, and then asphalt reclaimed which using vacuum rotating reclaim method. In the end, performances indexes of recycled asphalt were tested, such as penetration, softening point, ductility, viscosity, dynamic shear modulus, phase angle, bending creep stiffness. Performances indexes of Lanlian No.70 original petroleum asphalt were also tested. The performances indexes were compared of different aging degrees recycled asphalt and origin asphalt. Comparison results indicate that some performance indexes of recycled asphalt are decease; these indexes consist of penetration, ductility and phase angle. The other performances indexes are rise; those indexes include softening point, dynamic shear modulus, bending creep stiffness and viscosity. However, variation of performances indexes is minimal. Therefore, vacuum rotating reclaim method will not make asphalt ageing for considering equipment and human factors. We can use vacuum rotating reclaim method to reclaim discard asphalt concrete.

Abstract: This paper instancing of Harbin Sifangtai Cable-Stayed Bridge, simulates two kinds of non-linear bridge tower model considering the pile - soil - structure interaction and not considering using ABAQUS6.8 software. By comparing the frequency, modal, displacement of the tower top, acceleration of the bridge tower and stress of the tower bottom under two circumstances, analyzing and obtaining the conclusion that the seismic response results will be very different to a long-span Cable-Stayed Bridge, whether considering the pile - soil - structure interaction or not.

Abstract: This paper on wind generator set planetary gear had a simple introduction, and finite element method was used on the planetary gear transmission dynamics analysis, the conclusion was drawn that the different planetary gear in the direction of the force and deformation, so as to improve the quality of the gear is designed to provide a scientific basis.

Abstract: High cutting slopes with nearly horizontal soft-hard alternant strata are widely distributed in three gorges reservoir area, the soft and hard rocks are mainly mud stone and sandstone of Jurassic system. Sliding failure of this kind of slope is also the main geo-hazards in this area. Firstly, this paper analyzed the impact of topography, water as well as the differential weathering and combination characteristics of soft and hard rocks etc. on the sliding failure of slopes; secondly, sliding failure modes of this kind of slope were classified into four types including circular sliding, sliding along the extroversion structural surface, sliding along the mudded intercalation and wedge sliding, they were analyzed combined with case study. And lastly, support methods against the certain failure mode were put forward. The research results are significant to the support and treatment of high cutting slopes in Three gorges area.

Abstract: A new woodceramics was developed by furane resin and wood powder. Microstructures of woodceramics were performed by scanning electron microscopy(SEM). The effect of content of furane resin on carbon yield ratio,dimension shrinkage,apparent density,comprehensive strength and volume electrical resistivity of woodceramics were investigated. The results show that the woodceramics is a kind of carbon/carbon composite composed by wood charcoal and glassy carbon, the content of furane resin has a significant effect on the microstructure of woodceramics. With the increase of furane resin, generated glassy carbon increases and the connection between wood charcoal and glassy carbon will be strengthened. Carbon yield ratio, apparent density and comprehensive strength increase, and dimension shrinkage and volume electrical resistivity decrease as the content of furane resin increases.

Abstract: Due to the problems of potential corrosion and thermal expansion differences between traditional metal connecting pieces and carbon fiber poles, it is difficult for them to meet the operating requirements of truss structures in the environment of stratosphere. Based on the large scale composite space truss structure of stratosphere aerostats, the carbon fiber flange connection joints were studied in the present paper. Adopting the three-dimensional full five-directional braiding technology, Toray T700S – 12K carbon fiber is used as the raw material to manufacture flange joint preform, and to manufacture flange forming by RTM(resin transfer molding) process. As demonstrated by tension tests, the composite flange joints have equivalent mechanical properties with flanges manufactured by common aviation aluminum alloy, and meet requirements of stratosphere truss structure connecting pieces.

Abstract: For structure dynamic signals with low signal to noise ratio (SNR), Multi-scale EMD is proposed to extract useful information from signals contaminated by noise. This method is an adaptive way, and achieves better performance than traditional methods. A complex signal composed of signal and noise, which is first decompose into a series of different characteristic IMFs. Then sum of the first few IMFs including useful information and noise are further decomposed by EMD, and iterate this process for several times in order to extract useful information. The final step is deleting some IMFs obtained from the last decomposing which is considered as noise, and rebuilt the signal using the rest IMFs from different scale. This method can smooth signal effectively. The effectiveness of the proposed method is verified with the numerical simulating signal, and useful information in signals is retained. It also has some superior performances such as concise computer process, robust application, etc.

Abstract: Based on the summary of the status of land subsidence research, Biot Consolidation Theory is proposed to analyze the coupling of seepage field caused by precipitation. By use of Biot consolidation two-dimensional plane finite element calculation programmed, the land subsidence of the WenZhou Yongqiang plain caused by the exploitation of underground water was analyzed. The results are more in line with the measured data, so the method for analysis of possible land subsidence is practicable.

Abstract: Dynamic compressive tests were carried out for concrete specimens after exposure to temperatures 23°C, 400°C, 600°C and 800°C by using Split Hopkinson Pressure Bar(SHPB) apparatus. Cylindrical specimens with 98mm in diameter and 49mm in length were used in tests. The strain rates achieved in tests ranged from 30s-1 to 220s-1. The results showed that the compressive strength increases with increasing strain-rate, but decreases with the increase of temperature. However, the effect of strain-rate on improving the compressive strength of concrete decreases with the increase of temperature. Moreover, the strain-rate has an improvement on the peak strain of concrete, and the accretion rate increases with increasing temperature.