Advanced Materials Research Vols. 468-471

Abstract: This paper introduces the closed loop pressure computer control system which is suitable for the environment of kerosene medium. The system can satisfy the technical requirements of the pressure regulation in the test of the single –jet nozzle of aero engine , the pressure can be accurately controlled and its control precision is within ±0.01MPa. It indicates the principle and composition of the hydraulic system and computer measurement and control system. The paper introduces the design method and treatment process of the key technology, which includes the use of a proportional relief valve and a fixed throttle hole in hydraulic system, the use of PID control in closed loop control system, the use of high precision sensor and measurement method by grade in measuring system and the use of 24V precision steady voltage source. In the same time it indicates the actual application of the closed loop pressure control system.

Abstract: During hot pressing of the wood-based panels, the technological conditions, environment noises and performance of the sensors often result in errors in the temperature measurement. To improve the precision and reliability of data, multi-sensor technology is used for measurement data processing. The data consistency checking is performed by computing the confidence distance between adjacent sensors, and therefore the valid data fusion collection is determined. The weighted least square algorithm is applied to acquire high accuracy of overall estimation value by determining the information weight coefficient with the corresponding measurement variance of each sensor. The results of experiment demonstrate that the precision of overall estimation value is preferable than the partial estimation of each sensor and show the effectiveness and reliability of the algorithm.

Abstract: Plasma Display Panel (PDP) Lighting Inspection Machine is an important manufacturing facility in PDP production line. The key technologies of PDP Lighting Inspection Machine are discussed. Firstly, the advantages of PDP panels and the importance of researching on the PDP Lighting Inspection Machine are introduced. Then, the machine’s hardware structure including Programmable Logic Controller (PLC) control system, host computer system and visual positioning system is discussed in detail. Finally, the software implementation of the machine is also studied.

Abstract: It realized the visual navigation based on the marking line by putting forward marking identification algorithm with the combination of edge detection and environmental knowledge according to the characteristics of mathematical model and the navigation of marking line, and proposed path planning and driving control method by combining with the mathematical model of trolley to realize the visual navigation of four-wheel car based on the marking line. Taking the square mark trail as object to make experiment, the result shows that, the visual navigation system can track marking line in real-timely and control the robot driving along the path of marking line.

Abstract: The critical amount of corroded steel that causes concrete cover cracking can be readily calculated based on thick-walled cylinder theory. However, the results may vary significantly depending on how the rust deposition is considered. There are several rust deposition hypothesis proposed in the literature for modelling concrete cover cracking of RC structures due to reinforcement corrosion. Among them, three are considered representative ones and have been widely cited in the literature. They are: (i) assumes a certain amount of rust product carried away from the rust layer and deposited within the open cracks proposed by Pantazopoulou and Papoulia; (ii) assumes all of the rust products build up around the bar and all of them are responsible for the expansive pressure proposed by Bazant; (iii) assumes certain amount of rust products deposited into a porous zone around the bar/concrete interface proposed by Liu and Weyers. In this paper, all three rust deposition hypotheses were examined for the critical amount of corrosion to induce cover cracking. When compared to the test data available from the literature, it showed that the porous zone model proposed by Liu and Weyers gives the best predictions. Thus it may be concluded that assuming a porous zone around the steel/concrete interface would be reasonable and may be adopted in developing concrete cover cracking predictive model.

Abstract: Traditional one-dimensional, two-dimensional probe can only measure the micro displacement in one or two directions of space, therefore highly-efficient and highly-precise measurement requirements of the surface of the complex gear can’t be satisfied. Because 3D scanning probe can measure the micro-displacement in three mutually perpendicular directions of space, with it, continuous scanning motion measurement can be achieved and a large number of data points in three directions of space can be measured in a very short time, it is widely used in gear measurement industry at home and abroad. However, because of the limitations of mechanical structure of 3D scanning probe, installation errors and environmental factors, the measured three directions can’t always be strictly vertical, and in the measurement, there will be the interference and the coupling phenomenon among the three directions. The study about how to ensure the highly precise characteristics of 3D scanning probe using a reasonable calibration method has become hot and difficult. In the paper, a new calibration method is proposed, the different regions on the standard ball were continuously contacted by 3D scanning probe, and let the probe step 10 times on the each contact point of standard ball, 10 group of points data were read out. The point of subsection was determined based on the deformation of the probe in the experiment, the data of the probe collected in each segment were fitted by using of the least squares method. Several calibration matrices were so obtained, the precise calibration of 3D scanning probe can be achieved. This method is finally verified by experiment. The experimental results show that the method of calibration is feasible, and has the advantages of high-speed and high-precision, which lays a solid foundation for high-precision measurement of 3D scanning probe.

Abstract: Molding is one of the most versatile and important processes for manufacturing complex plastic parts. It is a method of fabricating plastic parts by utilizing a mold or cavity that has a shape and size similar to the part being produced. Molten polymer is injected into the cavity, resulting in the desired part upon solidification. The injection-molded parts typically have excellent dimensional tolerance and require almost no finishing and assembly operations. But new variations and emerging innovations of conventional injection molding have been continuously developed to offer special features and benefits that cannot be accomplished by the conventional injection molding process. This study aims to improving the life of stereolithography injection mold.

Abstract: Nano-CdS crack-free thin films were deposited on the conductive glass substrate with a two-electrodes DC electrochemical deposited method at low temperature (<100°C). The structure and properties of thin film catalysts were characterized by X-ray diffraction (XRD), SEM and AFM. Photocatalytic reactivities of nano-CdS thin film were conducted for removal of Rhodamine B (RB) in aqueous solution under ultraviolet light irradiation. The effect of the concentration and pH of the RB solution, the ultraviolet light, the exposure time, the size and the reusability of thin films on the degradation of RB were studied. It was found out that the exposure time, the light wavelength, the pH of RB solution and thin film’s size have much influence on the degradation. Reusability experiments show that the catalyst has well recycle characterization.

Abstract: Thermal expansion behavior of ceramic green bodies could be used to determine appropriate sintering procedure for ceramic materials. In this paper, green bodies containing alumina and calcium hydroxide was prepared by slip casting and their thermal expansion behavior was measured. Thermal expansion curve indicated that calcium aluminate (CaO•Al₂O₃, CA) and calcium dialuminate (CaO•2Al₂O₃, CA₂) are yielded by reaction sintering as intermediate phase compounds in green samples at temperature about 1160^°C and 1240^°C-1410^°C, respectively; and calcium hexaluminate (CaO•6Al₂O₃, CA₆) is yielded as target product at 1450^°C-1560^°C. Controlled sintering procedure was determined according to thermal expansion curve of green samples. Analysis result to properties of sintered samples indicated that thermal expansion behavior revealed to be a very simple and powerful tool to determine reaction sintering procedure of calcium hexaluminate ceramics.

Abstract: Through establishing solidification-heat transfer mathematical model of the super heavy steel ingot, the temperature distribution at different moments in the solidification process of steel ingot has been simulated. Based on the simulated temperature field and the law of solute redistribution, the carbon macrosegregation in the solidification process has been calculated. The results show that, the complete solidification time of the 600T steel ingot is 68.34 hours, and positive segregation of carbon forms in the ingot head, and the concentration of carbon near the upper axis which is higher than 81 percent of the ingot’s height is over 2 times than the average value.