Applied Mechanics and Materials Vols. 190-191

Abstract: Pulverized coal firing boilers are widely used in power plants. Coal is pulverized into very fine particles and then mixed with primary air in horizontal pipes in the case of exhaust pneumatic convey system. The pulverized coal particles are conveyed by primary air to the burner and burn in the furnace. The concentration of pulverized coal in primary air should be well controlled to keep the safe and economic operation of the boiler. Credible measuring and controlling system is needed in engineering applications. Investigation of the mixing process shows that the pressure of primary air drops rapidly within the process, which gives the possible way to determine the pulverized coal concentration. The rapid pressure drop is mainly due to the acceleration of the pulverized coal particles. With energy balance analysis, study of the relationship between the mass flow rate of the pulverized coal and the pressure changes within the mixing process is done. The governing equation is achieved and the method of using two sections to measure the flow is proposed. The measuring and controlling system can be established according to the method. As a result, the measuring and controlling method provides a new way to meet the needs of engineering application.

Abstract: This paper has put forward one method, combining with theory of decision tree and method of voting, and established one kind of multi-failure classifier of SVM, which could finish cross training, repeated classification and accumulative voting. This classifier could accomplish classification of failure bearings and do classification experiments among failures of kinds of bearings. The results have shown that this method could identify states of breakdown equipment for the purpose of diagnosis of failures of mechanical system accurately.

Abstract: To recognize volatile organic compound for colorimetric sensor array which constitute with chemical dyes. The rapid and low cost system can identify dilute compound. Every different compound is presented specified color on the colorimetric sensor array. In this research, we use CCD (charge couple device) to clearly classify the change of color on base, and make sure what the compound would be by Neural Network model. Based on the experimental result, we totally test for 33 group data, and precisely classify all type of volatile organic compound. It’s successfully to achieve the target in this research.

Abstract: On-line system was developed to gauge film thickness using isotope, by which the problem of difficulty in measuring wide film thickness was resolved. Two-point method, determining working curve of gauging system, was introduced, by which time spent on experiment could be decreased, and adaptability of working curve under different condition was improved. After analyzing measuring errors, emendation method for every error source was discussed .Method taking count of pulse number within a period of time was applied, by which measuring precision was improved, so this method can be used widely in other applications .This measuring system has obtained satisfying effect in measuring film thickness, and products can be bought in market .

Abstract: This paper presents a quality monitoring and prognostic method to evaluating quality of electronics through monitoring degradation path. Electronics multiple performance parameter degradation data are treated as multidimensional time series and described using multidimensional time series model to take into account implements of stochastic nature of environmental variables and to predict long-term trend of performance degradation. A degradation test is processed for certain electronics and three kinds of performance parameters degradation data are monitored for prognostics. A comparison between the predicted degradation path using multidimensional time series analysis, the predicted degradation path using one-dimensional time series analysis and the real degradation path of the electronics is processed and the results show that the degradation path prediction using the suggested method is more effective than one-dimensional time series analysis.

Abstract: For a class of non-matching uncertain nonlinear system such as stratospheric balloon-borne gondola azimuth control system, a new robust adaptive multiple sliding mode controller is proposed. In this control method, the virtual and the practical control variables are obtained by designing the multiple sliding modes step-by-step. For avoiding the chattering problem generated by discontinuous input, the traditional sign function is replaced by hyperbolic tangent function. Meanwhile, the CMAC neural network is used to approximate the system uncertainties and the derivative of virtual control input online, which can reduce the conservation of controller parameters design. The system stability analyses show that the control method can guarantee that the output tracking error and slide modes asymptotically convergent to boundary layer. The simulation results show that the controller has higher tracking accuracy, and stronger robust to nonlinear and uncertainty of system, and it also can be applied to other similar non-matching uncertain nonlinear systems.

Abstract: Text area extraction from video caption has become an important tool for content-based video retrieval. Test object is frame data intercepted from video data. This paper proposes an algorithm of edge detection to extract caption text that embedded in the video frame by grayed processing. Experimental results have shown that the proposed approach is very effective in text area detection.

Abstract: According to the current production situation of Chinese shipyards, this essay has made an in-depth study of execution process monitoring technology in block construction. Several key issues are discussed to implement the informatization and visualized display of execution process monitoring during the block construction period of shipbuilding. A prototype system is designed and developed to verify in practice. It realizes the management of the whole execution process and graphical display of yard and curved block.

Abstract: During the process of oil collection, treating power cable for the supply of electrical submersible pump unit as the medium of the underground signal transmission to the ground, it has broad application prospects and economic value. But there is large distance between down-hole devices and ground equipment, and electrical submersible pump unit condition monitoring system measures many parameters, and there is a converter of harmonic interference, therefore, it restricted the application of the underground power line carrier communication technology severely. Designing an overall plan for signal extraction and transmission system in the paper. Based on the low-frequency power line carrier technology developing a practical communication protocol, to ensure the reliability of communication.

Abstract: This paper deals with the problem of adaptive control for a class of nonlinear systems. The system considered in the paper contains non-parameterized uncertainties and periodic disturbances. A semi-global adaptive control method is proposed using the barrier Lyapunov functions. The method does not need to assume that the solution of the closed loop system remains in the domain of approximation by neural networks and guarantees that the solution of the system converges to zero.