Applied Mechanics and Materials Vol. 367

Abstract: In order to solve the question that the stator grounding fault current becomes bigger for large capacity of AP1000 generator, one Neutral grounding mode is studied in this paper through analyzing the principle on Large Generator with Compensation Resonant Neutral Grounding. Compared with High Resistance Grounding, this mode can limit the grounding fault current and protect the stator and winding better. Based on equivalent circuit model one 1250MW generator of AP1000 Plant is simulated, the data showed the method is feasible for AP1000 generator.

Abstract: Reduction in aerodynamic heating is the major design concern for hypersonic or hypervelocity vehicles which makes typical configurations blunt nosed for this flow regime. These blunt configurations make the space flight costlier due to higher wave drag. Therefore development and optimization of drag reduction techniques is the field of investigation and research in the area of hypersonic aerodynamics. The present work focuses on the investigation of concentrated energy addition technique for drag reduction. An in-house developed high precision compressible flow solver has been employed for the computational investigation of this technique. Parametric studies are carried out to investigate the effect of strength of energy source, location of energy addition and size of energy source.

Abstract: This paper presents the experimental result of a small scale packed bed of random spheres with encapsulated PCM being charged and discharged. A vapor compression refrigerator and heated room with fan heater were used to supply constant heat transfer fluid at a minimum temperature of -28°C for charging and 16°C for discharging. Even though the temperature differences were not fixed in the experiments, the performance of the thermal energy storage is depicted in the form of effectiveness values. Different results were obtained for charging and discharging the thermal storage unit. The differences are expected to come from natural convection and super cooling. The super cooling during the charging process was as high as 6°C.

Abstract: A practical design method of flyback switching power supply transformer was presented to solve the problem involved in too many formula and parameters calculation . This method explained the physics meanings of each parameter of the flyback transformer clear and concise, and gave the calculation methods and procedures of them based on practical engineering experience. An experimental result compared with the result designed by the software PI Expert 8 showed that the presented method was valid and more flexible.

Abstract: The USB which has high-speed streaming data and can plug and play meets the requirement of the data transfer mission. CY7C68013 have an ingenious architecture and can automatically deal with most data communication in USB 2.0 specifications. A high speed streaming data system based on EZ-USB FX2 was designed. The debugging interface based on slave FIFO of EZ-USB FX2 can send data in bulk from FPDA to upper computer; its convenient to system debugging work.

Abstract: Accurate and fast testing of digital circuits is very much essential in real time applications. Hardware analysis of digital circuits, which is otherwise very tedious and time consuming, is attempted using the artificial intelligence technique: Genetic Algorithms (GA). GA is used to find an input sequence to a digital circuit for testing, as it reduces the hardware utilization, complexity and computational time of the circuits. All the GA processes are simulated and implemented by using Xilinx 10.1 and SPARTAN 3E.

Abstract: In this paper, we deal with a class of zero-inflated Poisson regression models and propose a score test procedure for assessing whether there exists zero-inflation or not. The sampling distribution and the power of the score test statistic are investigated by a limited simulation study. Furthermore, a Bayesian inference procedure is also presented for comparison. Finally, a data set of fire accident is used to illustrate our methodology and our numerical results show that our approach is useful and appealing for the analysis of count data with zero-inflation.

Abstract: In order to achieve the online surface settlement monitoring of ballastless track,an online surface settlement monitoring system with difference image type has been established, of which the components, the preprocessing measures of images, the precise positioning methods of laser spot have also been researched. The device mainly contains a dot laser and a point-position measurement device that uses a CCD to detect the position change of the laser spot image. Any position change of the dot laser can be measured and the settlement for one point can be obtained remotely. The multi-point settlements can be obtained by using a series of such devices. Some methods such as automatic background sub-tractions and high-precision method for locating the centers of laser spots have been adopted to enhance the stability, adaptability and accuracy of the measurement system. The device has been used in some railway sites and it has the advantages of high accuracy, low-cost and easy installation.

Abstract: This work concerns a climate system in the point of view of controllability. We obtain by the Kakutani’s fixed point theorem and the controllability property of the linear parabolic equation that the superlinear climate system is null controllable in the case with interior control.

Abstract: J₂ perturbation has been widely studied for satellite formations in low earth orbit. However, the effects of some tiny aspherical gravitational perturbations such as high-order zonal harmonic perturbations, sectorial and tesseral harmonic perturbations are not negligible for long term formation flight. In this paper, after eliminating the effects of J₂ perturbation which accommodating it, research these tiny perturbations uses numerical analysis and acquires some conclusions. High-order zonal harmonic perturbations may cause divergence in radial, in-track and cross-track direction, while the drift caused by sectorial and tesseral harmonic perturbations is larger than higher-order zonal harmonic perturbations about two magnitudes generally, and drift in cross-track direction is secular.