Advanced Materials Research Vols. 694-697

Abstract: This paper presents a new approach based on the method of magnetic flux leakage (MFL) for the double-sided butt weld (DSBW) of the welding equipment such as the pressure vessel in order to detect and identify the weld defect. In this approach, a new magnetization structure is adopted whose magnetization direction is perpendicular to weld line, also, a new continuous non-contact scanning method is used, what aims to solve the problems about complex leakage magnetic field (LMF) space distribution. Then, the LMF distribution laws with non-defect (ND) and laws with precrack from heat affected zone (PFHAZ) are obtained through using these methods such as theoretical analysis, numerical simulation, and experimental study. Afterwards, this paper reviews the recognition analysis of the above-mentioned two kinds of state (ND and PFHAZ) by binding the contrastive curves. The outcomes indicate that the suggested method of MFL has realized the recognition of ND and PFHAZ; The numerical simulation results and experimental results match each other well and their correlation coefficient R is 0.9729. Furthermore, the results verify the feasibility and the validity for the suggested method. This is a new way for exploration detection of the double-sided butt weld.

Abstract: Magnetic flux leakage is one type of electromagnetic nondestructive testing (NDT) which is widely utilized in the testing the integrity of drill pipe in the field. In this paper, the 3D model of excitation unit is completely built and analyzed by ANSYS software. The magnetic field of drill pipe in the combination of full excitation device is showed by ANSYS software instead of the physic experiments which increases the efficiency tremendously and decreases the cost and achieves the anticipated desire. It is considered that this technique can provide the theoretical basis of drill pipe excitation device and the magnetic flux leakage testing of drill pipe.

Abstract: A new experimental apparatus has been developed for measuring the thermal conductivity of liquid by the two transient hot-wire method, which is based on the theory of one-dimensional unsteady heat conduction in infinite medium. The glass tubes, the heating line source and temperature measurement devices are designed in this experiment. As the temperature controller, low-temperature bath provides a constant water bath environment and current calibrator is the power source. Wheatstone bridge is used to test the relation between the temperature changes and resistance. Data acquisition and control unit is data acquisition devices of the Wheatstone bridge. As the temperature coefficient of platinum wire resistance is calibrated. It can be used to measure 32 groups of data from 10°C to 40°C at the every 10°C according to the experimental steps.

Abstract: This study presents the development of an in-situ analyzer, ‘IonConExplorer’, which can detect iron concentration in deep seawater at maximum 4000 meters with the method of spectrophotometry coupling with liquid waveguide capillary cell. The detection of limit is 27.25nM (n=20) for Fe(II) at 562nm, while the linear range is 100 nM - 1 μM. On the whole linear range, relative standard deviation of the seven replicate measurements is less than 2%. IonConExplorer is composed of pressure house and equipressure house containing control unit and fluid system, respectively. Via TCP protocol of network communication protocol(TCP/IP) when connecting to the ocean observing network, IonConExplorer transfers abundant real time data instantly to the shore-based station, demonstrating high temporal and spatial distribution resolution of iron.

Abstract: This study was performed in order to detect biased gait being occurred due to vestibular abnormality by using a data of acceleration being generated at foot during gait. Characteristics of acceleration being generated during gait was observed by comparing movement analysis data that was collected in a process of performing biased gait and general gait through induction of galvanic vestibular stimulation with acceleration data and biased direction and degree could be inferred through cumulative value of acceleration data by integrating it. As a result, it could be inferred that detecting gait bias after analyzing gait trajectory by using acceleration of left, right direction would be a feasible method. A significance of this study could be found in that a new possibility of utilizing acceleration was presented in an analysis of gait utilizing acceleration data. It is expected that the result of this study would be utilized for detecting abnormal gait that may be taken place by malfunction or damage of sensory receptor such as vestibular organ.

Abstract: The defect inspection is a crucial process for the plasma display panel (PDP) production that significantly influences the quality of final products. In this paper, we propose a defect identification and classification method that extracts and classifies defects using various image analysis techniques. First, we identify defects through binarization of images using Gaussian filter. Then, those defects are classified into seven different types by analyzing geometric characteristics of defects and utilizing a support vector machine (SVM) classifier. The experimental results using separate sets of training and test PDP images obtained from production lines are quite promising. Our method identifies defects effectively enough to be used in the real environment. It also achieves a high correctness in classifying various types of defects.

Abstract: Based on the use of exiting testing equipment research, summarize the request of detection and analyze the existing problems. According to the signal characteristics of the aero-engine synthesis adjuster, designed a kind of test system based on virtual instrument for it, and developed a software system used for the adjuster in situ detection and offline testing. National Instruments launched Compact RIO platform. Adopted this platform as hardware system can realize test system open and integration designed very well, and simulated sensors for the offline test part of the system. This test system realized parameters calibrating, channel testing and fault diagnosis function etc. for the adjuster.

Abstract: In order to solve the traditional Prony's method faults that is vulnerable to the impact of the noise, a interharmonic analysis algorithm that is combined total least squares-estimation of signal parameters via rotational invariance technique (TLS-ESPRIT) with Prony's method is used in this paper. The numbers and frequencies of harmonic and interharmonic in the power network signals are estimated by TLS-ESPRIT. Then their amplitudes and phases were analyzed by the Prony's method. After simulation, with this algorithm the parameters of harmonic and interharmonic can be accurately estimated in low SNR. It needn’t synchronous sampl data and has high frequency resolution. this algorithm overcomes the susceptible defect of the Prony's method by noise. The results of simulation prove that in the absence of synchronous sampling data, low SNR, the use of this algorithm, high frequency resolution, can accurately estimate the parameters of harmonic and interharmonic.

Abstract: The forest is considered as a precious and indispensable nature resource, but forest fire which can destroy forest resource safety and threaten human-living environment is considered as one of the severest disasters. How to monitor and collect information of forest fire at any time, it is a difficult problem for Forest Fire Prevention Departments to urgently solve. With the development of sensor technology, MEMS and wireless communications, wireless sensor network (WSN) has wide application in all kinds of fields. In order to prevent forest fire occurrence, this paper designs a monitoring system for forest fires based on wireless sensor network and GPRS network. The system gives the hardware design of wireless sensor nodes and software implementations, and chooses CC2530 to achieve the process of data acquisition and transmission, then sends the data through GPRS module to the remote monitoring center. By means of WSN and GPRS network, the system accomplishes data acquisition and long distance transmission.

Abstract: According to the complicated operation,time-consuming limitations of traditional CNC system test equipment,a test board with STM32 as the central controller is designed.The board has RS232 serial communication function,together with input and output channels of CNC system interface signals.Firstly, this paper introduces the whole structure and hardware interface circuit of the test board. Secondly,in the MDK programming platform,the test programs of data receiving, processing, control and communication are designed. Finally,the system test is accomplished through the joint debugging of the software and hardware system. The test board has been proved to have good stability and scalability,and successfully applied to the practical production.