Automatic Detection of Spills and Gas Pockets upon Ultrasonic Checking of Welds in Zirconium Fuel Claddings

The problem of automating detection of flaws (gas pockets and spills) in welds obtained by electron-beam welding, using the ultrasonic echo method which is implemented by slanted introduction of ultrasonic waves into a thin zirconium fuel shell, is considered. Algorithms for automatic detection of flaws and evaluation of their relative dimensions are proposed. Experimental results confirming the efficiency of the algorithms proposed are reported.     

Nondestructive testing of a bottom surface and construction of its profile by ultrasonic tomography

A technology for ultrasonic tomography aimed at the detection of flawed zones in unilaterally accessible concrete structures and the determination of their thickness and coordinates was presented. The construction of tomograms was described step by step. The results obtained by the current and previous tomograph variants were given. The tomograms of concrete specimens with specified model flaws and without them were obtained. Results with a lower noise level were obtained using the current tomograph variant. The need for the processing of a set of signals for the diagnostics and monitoring of concrete objects was shown.     

基于支持向量机和特征选择的超声缺陷识别方法研究

缺陷的自动识别在管道缺陷超声无损检测和评估中具有重要意义。提出了一个新的超声缺陷自动识别系统。该系统采用小波包分解提取超声信号的特征，采用混沌遗传算法来消除冗余和不相关的特征，并采用支持向量机（SVM）来对缺陷进行识别。为了验证系统的有效性，在实验室内作了大量的超声检测实验。实验结果表明，系统对管道缺陷具有较高的分类性能。     

基于图像配准的产品外形缺陷自动检测与分析

提出一种基于图像配准方法的产品外形缺陷自动检测和分析方案,可以对产品外形轮廓的缺陷进行定量测定,并对缺陷发生部位给出统计数据,为生产工艺的分析和改进提供依据。以瓷砖产品为例,进行检测和分析实验,结果表明,提出的方法是有效的。     

A Betatron Tomograph for Nondestructive Testing of Products with a Diameter up to 1000 mm Made of High-Energy Materials

Results of developing and testing a betatron-based tomograph with an energy of up to 10 MeV are presented. The tomograph allows investigating objects with a shined-though thickness of up to 250 mm in steel equivalent. In contrast to foreign analogs, a horizontal product arrangement is used; it creates the most favorable conditions for revealing such defects as cracks and delaminations, since in this position, the product is subjected to small deformations due to gravitational forces. The proposed scanning scheme has the properties of a third-generation tomograph and preserves the quality of the tomogram and the time it is gathered with a reduced number of detectors and tomograph dimensions. The results of evaluating the tomograph sensitivity with a test sample and the results of testing products containing defects are provided.

     

Theoretical basics for inspection of conducting coatings in aircraft fuel tanks

Problems related to testing the integrity of conducting coatings in aircraft fuel tanks are considered. Different types of flaws are analyzed, and the main problems encountered when detecting these flaws are revealed. The design of a capacitive device that improves the accuracy of the known technical solutions for testing the integrity of conducting coatings is presented. Theoretical foundations are considered for developing a mathematical model for shaping data signals in the testing procedure based on calculating the irrotational part of electric field inside the capacitive-gauge structure.     

A method for improving the accuracy of evaluating the dimensions of flaws in walls of tubular elements of structures

An algorithm for evaluating the real accuracy of the basic measuring instrument (exterior or in-tube flaw detector) in measuring parameters of flaws of a particular inspected tube was proposed on condition that the basic measuring equipment has no systematic error, while a verification instrument is considered as “absolutely” precise or “reference.” A statistical method of increasing the accuracy of evaluating the dimensions of flaws in thin-walled tube elements was developed on the basis of a correlation between the dimensions of flaw parameters. It can be taken as a basis for finding real values of parameters of flaws and for performing reliable calculations of the residual strength and residual life, for scheduling optimal periods for the next inspection of pipelines, and for ranging segments of a pipeline by a risk criterion, thus providing optimal scheduling of repairs.     

The development of a high-precision environmentally friendly method for measuring the thickness of rolled sheets

A triangulation method for measuring the thickness of flaws with the guided radiation of a sounding signal and its reflection from the surface of a rolled sheet and reception in transducer??s elements, which correspond to the measured thickness and other parameters of a rolled sheet, is considered. The high density of dust in the atmosphere of rolling mill stands and the thermal radiation of a heated rolled sheet are shown to be the principal disturbances in the measurement of such flaws by this method. For this reason, the spectral wavelengths adjacent to the IR imaging wavelength range, viz., thermovision and microwaves, are used in this triangulation method. The advantages and disadvantages of both existing and our coordinate measurement methods are demonstrated by the example of measuring the thickness of a metal sheet.     

Calibration Procedures for X-ray Streak Cameras and Elements of X-ray Measuring Circuits

Setups developed for the calibration of X-ray streak cameras and of elements of X-ray measuring circuits are described. Calibration procedures are described and calibration results related to the absolute spectral sensitivity, spatial resolution, distortion, sensitivity nonuniformity over the screen, sweep speed and nonlinearity of an X-ray streak camera, as well as the results of the calibration of filters and mirrors used in recording laser-plasma X-rays are presented. The absolute-calibration error for the streak camera is within ±10%, and the calibration error for the filter and mirrors is within ±2%. Methods for processing photochronograms are described that, using the calibration data, allow the correction of distortions introduced by the streak camera.     

Dynamics and wear of fragments of a lower part of a fuel assembly with free fuel elements

A procedure and findings of investigations of the dynamic characteristics and the wear of fuel elements in the framework of the development of a perspective design of fuel elements without fastening in a lower support grid are presented. At the first phase of the work, natural vibration frequencies and the dynamic rigidity of fuel elements are determined in various design variants of lower spans. Resonance frequencies of spans of fuel elements are revealed by minimums of the dynamic rigidity. At the second phase, investigations of vibrational wear within contact of fuel elements with cells of spacer grids are performed on models of a lower part of a fuel assembly. Four embodiments of the lower part of the fuel assembly are investigated. As a result of the application of high vibrational loads, the wear of fuel element cans and grid cells is observed in more than a half of contact assembles of fuel elements with spacer grids. The most and least wear-resistant designs of the lower part of the fuel assembly are determined by results of tests.     

Medical applications of the radioisotope X-ray fluorescence analysis.

The X-ray fluorescence, induced by small, sealed-off radioactive sources, can be applied as very sensitive method of analysis of trace elements in biological specimens. The preparation and technique for the analysis of small (0.1 to 0.5 ml) or larger (more than several milliters) volumes of liquid samples will be described, and the principal patss of the devices for analyzing only one element or a series of them are presented. The measuring time for typical analysis ranges between 10(2) and 10(4) seconds. For a simple X-ray fluorescence analysis the sensitivity of the method is varying between 10 ppm and 100 ppm when measuring during 100 seconds. A large number of applications of this method in the medical field is listed, concerning the analysis of trace elements naturally present in biological samples, and the analysis of elements employed as "stable tracers" in order to follow a dynamic process, or in order to label blood components, such as erythrocytes, leukocytes and platelets.     

An optoelectronic system for automatic inspection of the external view of fuel pellets

Results of the development and testing of a system for automatic inspection of the external view of fuel pellets for fuel elements of reactors of nuclear power plants are presented. The system operates on the basis of the optoelectronic method for producing high-contrast images of the pellet surface and subsequent computer-aided processing of the obtained images. During processing of information for identifying defective pellets, characteristics of the local dispersion of image density, training algorithms, and logical rules for making decisions are used. A database containing over 1000 images of pellets and simulators has been created for debugging software and training the system. The testing of the test specimen of the inspection system showed that the probability of detecting defective pellets is high (over 95%) for the test rate of 1 item per second.     

Determination of Faulty-Fusion Dimensions in a Cross Section of a Welded Seam by Radiographic Testing

The principles of using radiographic testing for measuring the faulty-fusion depth in a cross section of a welded seam are considered. The results of verification of the technique through examination of artificial and natural flaws are presented and some examples of the technique’s use in manufacturing are shown.__________Translated from Defektoskopiya, Vol. 41, No. 4, 2005, pp. 63–69.Original Russian Text Copyright © 2005 by Kruglova, Knyazyuk, Kortov.     

An algorithm for the automatic detection of inclusions in an inspected object with a scanning digital X-ray imaging system (one-dimensional variant)

The mathematical model of an output digital signal from a single measuring channel of a scanning digital X-ray imaging system containing a line of detectors is presented for the case where the main type of signal distortions is the noise due to the quantum nature of radiation. This model is used to develop a one-dimensional algorithm for the automatic detection of local “critical” inclusions in an inspected object and to obtain the statistical estimates of its efficiency based on a model example.     

[误差建模及精度保证方法]卧式加工中心关键几何误差元素甄别方法

以某卧式加工中心为研究对象,通过定义机床各部件局部坐标系间初始位置特征矩阵和初始位置误差特征矩阵,构建机床空间误差完备模型,解决传统建模方法中若干项几何误差元素缺失的问题。借助体对角线定位精度测量实验,对所建完备模型准确性进行验证,进而在此基础上提出几何误差元素实际参预度的概念及其计算方法,并由此形成基于空间误差完备模型和实际参预度的关键几何误差元素辨识新方法。分别根据计算所得实际参预度和灵敏度,对给定加工中心关键几何误差元素进行甄别。对比分析显示,相较于传统灵敏度分析,所提基于实际参预度的甄别方法具有更高的准确性。甄别结果表明,该加工中心关键几何误差元素有7项,且均与位置相关,与X轴进给相关的关键几何误差元素有4项,说明机床X轴运动组件制造精度可能存在较大缺陷。     

发动机燃料润滑性的研究进展

为适应汽车排放对燃料品质提出的严格要求,研究提高燃料润滑性是当务之急,中报道了测试柴油,汽油润滑性的HFRR和SBOCLE方法,以及组成对燃料润滑性质的影响和规律。     

管道内壁疵病光电检测装置

本文介绍了一种用于提取管道内表面疵病信息的方法和装置，论述了该装置的设计思想与实施要点。该装置主要用于各种细长钢管内壁质量的实时自动检测，能实现输入信息的数字转换、图象处理、识别分类和输出显示等功能     

Hydrodynamic load impact on vibrations of fuel element clusters in water-moderated water-cooled power reactor (VVER) fuel assemblies

For the first time, the hydrodynamic loads on fuel element clusters are specified by measuring pressure pulsations in the gap between external line of the fuel elements and the internal surface of the hexahedral casing in VVER-440 fuel elements in the initial hydrodynamic part close to the lower support grid and in the region of steady flow. It is shown that the formation conditions of vortex flow structure at the fuel assembly input influence substantially the hydrodynamic load levels and spectral distribution and the corresponding vibration response of the fuel element clusters in the heat carrier longitudinal flow. The findings may be used to analyze vibration processes in the fuel assemblies of water-cooled nuclear reactors.