Applied Mechanics and Materials Vols. 401-403

Abstract: Advantages of an electromagnetic (EM) flow meter includes nondestructive to flow and less sensitive to flow profile. For these reasons, study on applying EM flow meters to multiphase flow measurement has been attracting researchers. A series of experiments were completed. Resistance between electrodes, gas void fraction, liquid phase mean flow speed and EM flow meters out put were measured. Relations between these data were analyzed. The results showed that certain modified factor could be used for the EM flow meter to measure water-gas two-phase flow.

Abstract: This paper firstly presents the operation principle of individually ventilated cages (IVC) system. Measurements on micro-environment of IVC system in laboratory animal room at University of South China are conducted to attain the internal environment parameters (Temperature, humidity, air velocity, air cleanliness and noise). Research results show that internal micro-environment parameters basically meet national standards about the barrier environment, but internal air distribution is uneven. In IVC system, air velocities in the edge side are higher than in the middle side, and the maximum air velocity is about 10% larger than the minimum value. Temperature in internal micro-environment depends on indoor temperatures which IVC system located in, and there has a close correlation between air velocity and temperatures. Internal environment evaluation could provide the first-hand research materials for guiding the breeding and management of laboratory animal.

Abstract: In order to ensure the security protection level for smart meter to fulfill the requirements of state grids information security protection grade, promote the applications for the smart meters automatic detection pipeline, improve smart meters test efficiency, the state grid company has carried on the revision for Q/GDW 365-2009 "Security techniques of information interchange authentication specification for smart electricity meters", and has generated the Q/GDW1365-2012 standard. This paper has proposed the smart electricity meters security protection function realization method according to Q/GDW1365-2012s relevant revision item, combined with the questions often appears in practical work.

Abstract: According to the nonlinear characteristics of transformer fault symptoms and fault types, the application of BP neural network to the problem of transformer fault diagnosis is presented. With a characteristic of the gas content ratio as the input, fault diagnosis model is established by using MATLAB software to achieve improved Newton method. And the simulation experiments show the effectiveness of the model of fault diagnosis.

Abstract: With characteristics of impulse noise and Gaussian noise, we propose a new denoising method to infrared image. We use Sobel operator to obtain boundary information, and determine the denoising method based on the pixel number of the peer group, denoising impulse noise and Gaussian noise with median filter and Wiener filtering. Experimental results are provided to show that the proposed filter achieves a promising performance in PSNR and boundary information, compared with the median filtering, Wiener filtering and peer group algorithms.

Abstract: A long rail straightness measurement method is given for the portable laser alignment measurement system which is based on laser shearing interference fringes. Through theoretical derivation, mathematical model is set up between the laser phase differential linearity error and shearing interferometry. Large numbers of experiments have verified correctness of long rail straightness measurement method, analyzed the cause of error and provided ways for error reduction.

Abstract: The video detection technology is a very active branch in the research field of machine vision, and the detection of vehicle trajectory by the stationary camera has become more and more important. However, there is little research on the measurement error of left-turn vehicles trajectory.This paper not only studies the relationship between the measurement error and longitudinal distance; but also relationship of measurement error and transverse distance. Their mathematical models are constructed and each of the variables in the models is analyzed. Then in the case analysis of certain intersection, the experimental results have shown that the proposed funtions can describe the relationship between measurement error and the parameters. It can provide the theoretical support for the measurement error problems of obtaining trajectory by video detection.

Abstract: Shearography is a whole-field optical technique used to measure the surface displacement derivatives. The digital shearing speckle interferometer (DSSI) allows the acquisition and observation of fringes in real time without having to undergo the photographic wet-process and the filtering procedure. In this paper, the principles of DSSI are introduced. In this method, the undeformed speckle image is firstly digitized and stored into the computer through a CCD camera. The subsequent frames of the deformed object are then subtracted continuously from the stored reference frame, thus a fringe pattern is formed. By counting the fringe order, the displacement derivatives at any point on the surface of the object can be determined. A case study using DSSI method to measure the derivatives of surface displacements is presented.

Abstract: Aiming at the problems of measurement of the position and shape error for macro-axis, the idea of "software is the instrument was designed to assessment system based on the combination of MATLAB and MCGS . The system can complete the measurement data receiving, data processing, curve output, shape and position error calculation, alarm display, such as a series of functions.

Abstract: To study discharge coefficient linearity of screw-in venturi flow sensor, the effect of the screw-in blade attached to the sensor on discharge coefficient was analyzed, the structure of the screw-in blade was optimized by CFD software. Through the observation of velocity field, it was found that discharge coefficient will basically remain unchanged at low Reynolds number, while it declines greatly at high Reynolds number because of the guidance of the screw-in blade, as a result discharge coefficient linearity becomes better at the same measurement range. Orthogonal array of DN100 was designed for 10:1 measurement range to explore effect of geometric parameters of the screw-in blade on discharge coefficient linearity. Optimum structure for the screw-in blade is determined as follows: number of blade is 4, back slip angle of blade is 50°, front slip angle of blade is 5° and height of blade is 10.5mm. The numerical simulation indicates discharge coefficient linearity of the optimal screw-in venturi flow sensor is 0.601%,which is better than that of double-cone venturi flow sensor.