Advanced Materials Research Vol. 413

Abstract: The energy equations of MDOF bridges are established based on the energy equilibrium theory. With considering the seismic characteristics, the FEA model of one double-column pier of passenger dedicated line is established in order to research the seismic energy response and its distribution rules when MDOF bridges entry the nonlinear state. The study results are obtained as follow: Bridge subjected to minor ground motion is depended on damping energy dissipation to consume seismic input energy. On the contrary, a large number of inelastic deformation is generated when bridge is subjected to strong ground motion. So the seismic input energy is mainly consumed by hysteretic energy dissipation. So, some meaningful references are provided for the seismic design for bridge by using energy concept.

Abstract: The energy equations of multiple degree of freedom bridges are established based on the energy equilibrium theory. And, the finite element analysis model of one double-column pier of passenger dedicated line is established in order to research the seismic energy response and its distribution rules. The study results are obtained as follow: The seismic input energy is equal to the sum of other seismic energy response of bridge at any instant. Meanwhile, the rationality of seismic energy equations can also be verified. And, the flexible base can only affect the seismic energy value of bridges and can not affected the trend of seismic energy. So, some meaningful references are provided for the seismic design for bridge by using energy concept.

Abstract: The homogeneous rare-earth catalytic system was used to initiate the polymerization of isoprene, and a novel IR was synthesized with high molecular weight and narrow molecular weight distribution. According to the self-developed rare-earth IR properties, a study on IR and IR/NR blend was made. The effect of JiHua rare-earth IR on the vulcanization characteristics and dynamic properties in IR/NR blend was investigated and compared with IR (SKI-3) synthesized with titanium catalyst system and rare-earth isoprene rubber (SKI-5) made in Russia. The results showed that JiHua rare-earth IR to be developed independently was a novel synthetic rubber with excellent comprehensive performance, and it can be used independently and partly substitute natural rubber to make tire. In the IR/NR blend, Not only vulcanization characteristics and the safety in operation for NR was greatly improved, But also dynamic properties of vulcanizates such as dynamic cutting resistance, abrasion resistance, wet-skid resistance and aging resistance were improved to different degrees. These properties reach or surpass the level of the foreign similar products like Russia SKI-3 and Russia SKI-5.

Abstract: The desanding in heavy oil has been indispensable to oilfield exploration and production. The methodology of natural sedimentation is considered the effective way in oilfield, as a consequence of the best separation effect, a large handling capacity, low energy consumption, simple operation and low-carbon green. This paper did some research on natural sedimentation separation characteristics in the desanding of heavy oil, through experimental study, in order to test setting time and viscosity of various kinds of size in heavy oil, which indicates the relationship of viscosity, size and sedimentation rate. Not only make sure the relationship of setting time, viscosity and size, but also the boundary between floating zone and stable region in the desanding of heavy oil, Based on these data which has an important guiding role to make sure the time that natural sedimentation takes for oil-water-sand, desanding properties of heavy oil and separator size.

Abstract: Based on a success case of deepwater drilling at Equatorial Guinea in West Africa Gulf, an experimental study has been made, which was focused on the chemical composition and microstructure of the anchor material of the mooring system used in the drilling process. The percentage composition of chemical elements in the anchor material and the material microstructure were obtained. The experimental results showed: to a certain extent, the anchor material met the performance requirements for deepwater drilling at Equatorial Guinea as a result of the reasonable percentage content of each chemical element and the ultrafine structure. Through the experimental analysis, some performance characteristics and microstructure feature that the anchor material should have were further made clear to adapt to the deepwater drilling.

Abstract: High-voltage power switching process will produce over-voltage and impulse current, it will bring a range of complex power system problems and when cutting and closing the high voltage the asynchronous motor will also produce over-voltage and impulse current. They have some impacts on the high voltage asynchronous motor, may result in equipment damage. So how to control the production of the impulse current and reduce the size of the impulse current are the core issue of the switching device. This paper highlighted the impact of over-voltage and current effects on the asynchronous motor, finally, this paper refer to the harm of the impulse disturbance and provide some methods of reducing the impulse current, so that has certain significance to people of the actual power grid operation.

Abstract: Chaos theory is an important aspect of non-linear research, and has infiltrated a number of disciplines and engineering fields. With the increasing scale of power systems, the nonlinear characteristics are more and more obvious, under certain conditions there will even be chaotic behavior, appears as irregular electromechanical oscillations, constituting a threat to the system.[1-3]. So it becomes an urgent need to take effective control measures to curb or eliminate the chaotic oscillations in the non-linear power system. Chaos oscillation in the power system is harmful and should take measures to suppress and eliminate. There have been a lot of chaos control methods, and each has its own advantages and disadvantages and different application. This report mainly studies fuzzy control among its advantages and the features of the power system.

Abstract: In grid-connected photovoltaic system, the inverter, grid device, power electronic devices etc. They consume a large quantity of reactive power; mostly in distribution system, a perceptual load must also consume reactive power, these makes big interference interconnection of photovoltaic system after serious test the voltage stability. Therefore, carry on research of voltage stability in grid-connected photovoltaic system has important significance. With the voltage stability, voltage quality, analysis the possible influence of photovoltaic grid power system on power grid in safe and stable operation. Discuss probable bifurcation behavior in photovoltaic grid system. Introduce the basic concept of bifurcation, and then review the application of bifurcation theory in research of voltage stability from two aspects: static bifurcation and dynamic bifurcation. Finally take a look at bifurcation theory research of photovoltaic grid system voltage stability.

Abstract: Present thermal manikin is always enclosed by hard materials, and not covered with surface coating. So the surface condition of thermal manikin is very different with real body, which reduces thermal manikin’s stability. Therefore the research on thermal manikin’s surface coating and its effect on thermal manikin’s stability are necessary. In this paper, an appropriate material was selected to be thermal manikin’s surface coating and the satisfying result in improving the stability of thermal manikin was achieved. Firstly, five kinds of soft materials were selected to be candidate surface coating materials, which were EVA, HTV, TPU, medical used silicon rubber and cotton fabric. By lots of experiments and fuzzy mathematics theory, HTV was analyzed to have satisfying optimization performance than other materials and can be used as thermal manikin’s surface coating. Finally, to evaluate the effect of HTV surface coating on thermal manikin’s stability, comparative experiments were performed in climate chamber when thermal manikin covered with HTV surface coating and did not cover with HTV surface coating. Results show that HTV surface coating can obviously improve the stability of thermal manikin.

Abstract: Based on static bifurcation theory, a systematic procedure for tracing the bifurcation points of power system voltage instability was presented. Two main kinds of bifurcations, a common saddle node bifurcation (SNB) and a kind of bifurcation—limit induced bifurcation (LIB), which can cause the voltage collapse, were studied simultaneity and all types of device limits were considered. Firstly, make sure the mathematical model of the system. Secondly, starting from the basic running point of power systems, a predictor scheme was presented to find all the limit points (LP) and identify the LIB points; an adaptive step size control method considering the curvature of the manifold was introduced for tracing the equilibrium manifold and the detection of the SNB points without the existing of LPs. The two schemes were combined to lead a more effective method for SNB, LP, and LIB detection.