Applied Mechanics and Materials Vols. 488-489

Abstract: With the advantage of high-security, energy-saving and high efficiency, the self-circulation evaporative cooling technology provides an ideal solution for the cooling problem of stator collector ring in hydro-generator. In this paper, the operation characteristics of self-circulation evaporative cooling system of single stator collector ring under different work conditions were analyzed by experiments. The experimental results show that the cooling performance of this new cooling system is satisfactory. The temperature distribution of stator collector ring and system pressure distribution were discussed on the basis of experimental data and those variation tendencies were concluded. The research results in this paper provide the basis for further researches and practical application of this new cooling system.

Abstract: The self-circulation evaporative cooling system (SECS) of stator collector ring is a kind of new cooling technology, utilizing the evaporating of work fluid to cool the stator collector ring of hydro-generator. In this article, the thermodynamic processes of SECS of stator collector ring were analyzed by the second law of thermodynamics. The entropy production and power loss of isolated SECS were analyzed. Based on the distinctive characteristics of SECS, a performance evaluation function was proposed. The influence of heat load on was discussed by simulating. The conclusions provide the theory basis for the application of this new cooling technology.

Abstract: This paper proposes the modle based on Grey system theory to evaluate conditions of transformer. The model of unequal-interval GM (1,1) and GM(1,1) model including buffer operator are established to predict the values of gas dissolved in oil of transformer. According to the results of prediction,state of power transformer will be divided into five categories in order to propose corresponding repair strategy.The method is effective on providing support for transformer condition maintenance.The proposed method has been verified by the experimental data.

Abstract: Considering the problems of small sample, non-linear, multi-variable coupling and dynamic of plastic injection molding process, an intelligent modeling methodology based on partial least-squares (PLS) regression and neural networks (NN) was presented to predict the quality index of injection-molded parts in this study. This modeling approach extracted relatively few latent variables as inputs of intelligent model by using correlation analysis and principle components extraction. Then a constructive approach and program was used to optimize training process and improve the precision of modeling. Furthermore, the performance of quality prediction model was evaluated and tested by its application to verification tests. Compared with normal neural networks, PLS-NN model has better prediction performance and generalization ability, the simulation result proved that this approach was effective.

Abstract: Study automotive transmission shaft abnormal noise control with engineering database,and improve the abnormal noise control process using experimental analysis,CAE technical analysis,sound quality and other professional knowledge. Then analyze the process,and establish the appropriate sub-database. Database management system organizes the various modules and promotes exchange of the user and the database with Human-Computer interface. On this basis it reveals the necessity of combination of engineering problems and database. Besides,it is verified that the entire process is effective relying on a miniature car.

Abstract: Aiming at full view field control problems of infrared thermal imager during Light stress reliability test,this paper designs a standard light source with wide view filed, makes infrared target and background achieve a quantitative and standardized output and provides an important basis for reliability test of infrared thermal imager,it is a kind of indemnification for improving the quality of thermal imager. In this paper, the background of light stress blackbody and the target of infrared target is designed to provide a standard light stress source for test, the design of parallel light pipe can provide a wide view field. Application of digital image processing technology achieves automatic monitoring during test and computer can control output on light stress background and target according to needs ,so this system is automated from image acquisition to data processing.

Abstract: Based on the normalization of sample datas errors, a feasible reverse solving method of regularization is studied to avoid ill-posed problem in inverse problem. The analysis result shows that the high robustness in selection method of regularization parameters, rather than the strategy of regularization, is the key factor deciding the effectiveness of regularization.

Abstract: The reliability and accuracy of driver gaze behavior detection was improved by the multi-dimensional feature fusion method. In view of the effects of the complexity of the driving environment, a variety of working conditions and the diversity of gaze behavior characteristics,with support vector machine (SVM) theory technique, the multi-dimensional feature decision-level fusion was proposed to estimate the different kind model of the driver's gaze behavior. The results show that the T characteristic curve proposed by the gaze behavior parameters of the transverse width between the eyes and the vertical distance between mouth and the midpoint of two eyes, combined with the driver's eyelid closure and the proportion and location characteristics of iris-sclera were studied to get the characterization of the driver gaze status. The simulation results indicate that the adaptability and accuracy as well as the intelligence level of the bad fixation characterization information screening are significantly improved by using the pattern classification and decision technology of multi-dimensional feature fusion.

Abstract: The optimum spark timing, biogas flow rate and excess air ratio are the important factors influencing the power output performance of ignition’s biogas engine. In this study, the biogas flow rates are set as 220, 240 and 260 L/min, respectively. Under each fixed biogas flow rate, it tests different excess air ratios, ranged from 0.8 to 1.2. The experiment results indicate that the optimal parameters are: spark timing(BTDC13), biogas supply rate(260L/min) and excess air ratio(0.95).

Abstract: In order to monitor the press of mining roof in combined face, the paper design a coal mining roof pressure monitoring system. The system includes roof pressure testing device, intelligent portable data acquisition meter and upper lever computer monitoring and processing system. Roof pressure testing device is mainly testing the pressure of mining roof and transmitting pressure data to intelligent portable data acquisition meter by infrared communication technology within the allotted time. Intelligent portable data acquisition meter can also transmit pressure data to upper lever computer monitoring and processing system for further analysis and storage. Test results indicate that the system can achieve long-term continuous monitoring to roof pressure and provide the reference frame about roof control through the analysis of the monitoring results.