Applied Mechanics and Materials Vols. 241-244

Abstract: A tracks status inspection system based on coordinate transformation matrix algorithm was introduced. The structure, composition, measurement principles, design and test of the inspection system were elaborated. It was composed of two handy carts. Variation of tracks status could be denoted by three relative turning angles under the two coordinate systems of the two carts by means of coordinate transformation matrix, and tracks geometry parameters could be obtained using the matrix recursion algorithm. The instrumentation can carry out inspections such as track height, height irregularity, level irregularity, track gauge, track alignment and triple pit and so on.

Abstract: In this paper, the pump performances intelligent test systems is introduced. Work principle of the test system is analyzed, and the hardware architecture and software design of the system is given. The principle of analog signal calibration and frequency test with period is discussed emphatically.finally, the mathematical model of data processing are also given.

Abstract: An on-line detection system, which detected for µg/L level of iron, combined the automatic concentrate device and o-phenanthroline spectrophotography. The improved method has four innovations: the automatic concentrate device, the airtight structure of storing ammonia, a temperature sensor controlled the action of the rotating and dumping, an electronic balance with magnetic stirring to control the coloration process. The detection limit for iron was 0.717μg/L, the sensitivity of the improved method was 0.020. The obtained results by using the improved method were in good agreement with those obtained from graphite furnace atomic absorption spectrometry.

Abstract: A novel virtual instrument operated on different computers, peripherals, measured node and databases connecting to the network based on network and database technology is proposed to achieve resource sharing by using of the virtual instrument electronic test system (VIETS) developed by Jilin University. Users can not only remotely control the instrument measurement, collection, analysis and processing data, but also conveniently monitor the test site, which benefit to the foundation for setting up networked virtual electronic measurement laboratory. A mixed-mode of C/S (client/server) and B/S (browser/server) and a system structure include user client, internet, server, client device and measurement and control equipment was presented. Network function was also achieved by using of LabVIEW, MyEclipse, MySQL and other technologies to accomplish the database design, server management website design and the communication. Thus users can remotely both monitor and control the test instruments through the network function of VIETS.

Abstract: A tube conveying flow under vibration can induce a number of interesting phenomena, which can be used to measure certain fluid and flow parameters. For example, Coriolis flow meter which uses vibrating tube is now acting as a key mass flow rate instrument in industry. However, the complexity of flow often requires several parameters to be measured in one time. We studied the vibration behavior of a single rigid straight tube connected with elastic bellows at each end in a flow pipe line. Electrical exciters were used to force the tube to vibrate. Displacement transducers were used to measure the amplitudes and phases of tube’s vibration. Flows through the tube were water or water-air two-phase. The preliminary experiment showed that density, flow rate, viscosity, as well as pressure, which are important parameters for the flow, could possibly be measured in the same vibrating tube.

Abstract: It is very important for researching the growth and cultivation of plants that real-time monitoring of photosynthetic physiology & environmental parameters and analysis of relationship between these parameters. In this paper, an indoor cultivated Michelia alba monitoring system was built, which could continuously monitor leaf's CO2 exchange rate, transpiration rate, air temperature and humidity, soil moisture, photosynthetically active radiation and other parameters in real time, and could also analyze the relationship between the photosynthetic physiological parameters and environmental parameters. The results show that the diurnal variation of indoor cultivated Michelia alba leaf's CO2 exchange rate presents a bimodal pattern, which shows a midday depression. The diurnal variation of photosynthetically active radiation presents a single pattern. The diurnal variation of air humidity presents a “ S ” pattern, but the overall variation is little. The environmental factors that influenced the Michelia alba photosynthetic physiological characteristics most greatly are the photosynthetically active radiation and temperature.

Abstract: For the inductosyn angle measuring system axial angle digital converter integral loop and the VCO linear range restricted problem of tracking speed and control voltage, angle measurement system has been developed, the angle measurement system based on time subdivision method. The system mainly consists of rotary table, excitation power, signal pick-up circuit, FPGA control module, display module, and serial communications modules and host computer. FPGA is used as control core in the angle measuring system, and the high-speed FPGA signal processing has satisfied the measurement requirements. Induction signal is subdivided by high-frequency clock pulse. Angle measuring system has achieved angle measurement and communication functions. The experimental results show that the angle measurement system accuracy is ±3".

Abstract: Water and fertilizer are two important factors in seedlings growth and development, the reasonable management of water and fertilizer can play a greater growth potential for seedling, and blind management of water and Fertilizer not only is harmful for seedling growth, but also will lead to the water resource waste and environmental pollution. In order to precisely determine the seedlings fertilizer demand, this paper presents a method seedlings fertilizer and water measurement and control system based on wireless sensor network, the system can realize automatic deployment of information acquisition node, data self-organization transfer, namely, wireless communication, and can accurately detect information of soil water and fertilizer and identify water and Fertilizer on the best demand of seedlings growth stages for different seedlings, different regions, different period of climate and seedling growth status, so the best water and fertilizer control is achieved in seedling cultivation. This system were introduced and analyzed from the hardware structure, software structure and so on in this paper, and it has the advantages of low power consumption, low cost, good robustness, flexibility and so on. The experiment results shown that the system is practical and efficient, which can be applied in farmland, and nursery area.

Abstract: The discreteness of device parameters exists in the analog signal processing using conventional phase measurement methods, and the error caused by threshold voltage of comparator is difficult to estimate and eliminate. Due to this shortcoming, a method based on TMS320F28335 eCAP module for measuring the phase difference is presented. Firstly, the AC signal is amplified and filtered to eliminate the error introduced by electromagnetic interference, and then the digital signal through the Schmitt Trigger designed by CPLD is converted to wave signal with the same frequency of the signal, by capturing the edge-triggered, enters the capture interruption subroutine to calculate the number of the sampling points of one period, finally the phase difference is calculated according to correlation method. Hardware circuit and software flow chart are given. The experimental results verify the method has higher reliability and precision than conventional methods.

Abstract: By in-depth analysis and summary of tower suspension insulator strings images collected, a algorithm of edge feature matching of suspension insulator strings was proposed to detect the windage yaw angle in real-time. By filter, image grayscale, interframe difference and edge feature matching which based on invariance Generalized Hough Transform (IGHT) and local feature of suspension insulator strings stored in a database, the coordinates of the ends of suspension insulator strings were determined, and then the size of windage yaw angle of suspension insulator strings was calculated. The algorithm proposed can provide translation, scaling and rotation invariance, and be better matching accuracy and robustness.