Advanced Materials Research Vols. 889-890

Abstract: In order to analysis the properties of hydrogen storage alloy, hydrogen storage properties, the test principle of pressure-composition-temperature (PCT) was analyzed in detailed, the new type PCT test system was designed on the base of the state equation of ideal gas. The PCT test system is composed of five parts: air supply system, vacuum system, response system, data acquisition system and electric control system. The PCT test system can be carried out in four channel linkage experiments. The hydrogen storage performance experiments of LaNi5 hydrogen storage alloy were carried out by using this system. Hydrogen absorption curve was gained by two kinds of modeling methods. Results show that: the test system can test the hydrogen absorption curve smoothly, efficiently and accurately. The design of this system is reasonable and the test result is reliable.

Abstract: The vibration is severe for a hydraulic turbine runner chamber of a large bulb hydraulic generator set. A measurement and analysis system is composed of an acceleration transducer, a charge amplifier, and a dynamic data collecting & analyzing system. It is used to test the frequency spectrum, which provide a basis for the optimization design based on the modal analysis, so that its natural frequencies can stagger these frequencies of vibration sources, the resonance does not occur and the vibration is reduced.

Abstract: The gear processing technology can be analyzed by testing the gear noise. For this purpose, a set of gear noise test system was developed. A DSP hardware system was designed to test and analyze the gear noise. The signals were transferred to the PC through the USB module for further comparative analysis. The gear noise signal spectrum analysis was carried out in the PC signal processing software. The experimental results show that the system can accurately acquire and process the gear noise signals, and it can be used to analyze the gear processing.

Abstract: Noise signal analysis method is widely available for gearbox bevel gear fault detection. However, the noise from the gearbox is usually concealed by background noise, which leads to poor efficiency analysis. This paper reports an ensemble empirical mode decomposition (EEMD) and neural network method for bevel gear fault detection. To extract useful signal, EEMD algorithm was firstly applied to get rid of the background noise. Characteristics from a group of discriminating defect status were then chosen to build the eigenvector. Finally, the eigenvector was imported into a back propagation (BP) neural network classifier for defect diagnosis automatically. Experimental results show that the proposed approach is capable for signal denoising and providing distinguishing characteristics of founded fault. The developed method is an accurate approach to detect fault for tested bevel gear.

Abstract: For the study dynamic characteristics of three-dimensional roll forming machine, this paper develops a dynamic characteristics measurement and analysis system of three-dimensional roll forming machine, which is based on the U.S. NI company software development platform, including the development of hardware and software part .The realization of dimensional roll forming machine dynamics parameters collection and analysis, the experiment proved that the test system can be easily field measurements demand dynamics parameters, to improve the three-dimensional roll forming machine precision and control accuracy to provide an experimental basis.

Abstract: At high temperature conditions, the glass molten by the combined action of gravity and surface tension form an oval. Through digital image measurement system we can obtain glass molten oval contours and the contact angle. By the Bashforth-Adams equation which deduced from Young- Laplace equation to obtain the glass molten' surface tension at the corresponding temperature conditions. This method has good reproducibility and accuracy.

Abstract: A temperature real-time monitoring system was devised based on MATLAB GUI. It improved the data processing speed and software development efficiency. Serial port tool box in MATLAB and Modbus communication protocol were used to link up thermostat to PC. Variety operating modes can be achieved in different parameter configurations. The software source file is 304 KB. Test results show that, the temperature response curves of different parameters configuration are quite accurate. The sampling interval was 1s and the measurement accuracy was 0.1°C.

Abstract: Arc faults are one of the main reasons of electrical fires. For the difficulty of series arc fault detection, very few of techniques have successfully protected loads from arc faults in low-voltage circuits, especially in China. When series arc faults occur, shoulders will appear in load currents. The shoulder widths of non-arc faults such as normal load arcs are stable, while those of arc faults are variable because the appearance of arc faults is erratic. Therefore, a novel detection method based on shoulder characteristics was proposed. To better capture shoulder widths, original currents were firstly converted into pulses. Then, the pulse widths were used to detect arcs and the fourth-order cumulants of their differential were used to distinguish arc faults from normal operations. Finally, an arc fault detection device (AFDD) prototype was developed for test. The results show this prototype can discriminate arc faults effectively from normal operations.

Abstract: Automatic monitoring of hydrologic properties such as water velocity at short-time intervals is critical for understanding watershed eco-hydrological processes. This can also be used to study the laws of stream flows and interactions ecological process. The advent of modern electronic technology (and the near-perfection of especially sensor and data collection technologies), has made it possible to use automatic monitoring systems to continuously measure hydrologic properties at short-time intervals. This paper introduces one such paperless flow velocity measuring/recoding system. The system uses a photoelectric sensor that is mainly comprised of photoelectric velocity sensor and pulse recorder. The system uses propellers (with reflective panels and photoemission cells) to transform flow velocities into optical pulse signals. It also uses photosensitive tubes to transform optical pulse signals into electric pulse signals. The electric pulse counts (generated in unit time) are recorded via pulse recorders. This therefore accomplishes automatic monitoring and continuous recording of fluid flow velocity.

Abstract: The white-light interferometry (WLI) has been widely used in 3D topography measurement. This paper introduces a white light phase shifting method for interferometry with the combination of Hariharan phase shifting and WLI. A micro/nanolevel mechanic system was designed and built for the experiments. To verify system accuracy and feasibility, a 100nm step height standard was measured by the designed system and the metrological nanomeasurement machine (NMM). Results of 102.7nm and 102.5nm are obtained respectively. En value of 0.14 is calculated, demonstrating the reliability of result measured by the system. Based on classic nanoquantity traceability system, the measurement results can effectively traced back to the definition of nanometer magnitude, which can improve the accuracy of measurement.