Search

The paper gives an information overview and analysis of metal magnetic memory method for metal stress-strain state assessment. The object of this research is an alternative approach to the study of metal constructions by changing their magnetic parameters. The physical basis of the method is the magneto-elastic effect. The purpose of the paper is the analysis of new method and search for the prospects of its further development, as well as setting targets for further research. The paper is written in the form of an analytical overview. It considers and explains structural transformations in metals under elasto-plastic deformation. Also, the empirical dependence of magnetization on magneto-elastic strain in metals has been shown, stresses magnetization increase in elastic range, its slight reduction when transition to plastic deformation and the effect of residual magnetization after unloading have been explained. The mathematical models of the MMM method have been presented. The paper gives brief theoretical principles of the method and preliminary assessment of the level of useful signal. The prospects of the method for diagnosis of metal pre-defect stress state have been estimated. The task of further researches has been set, such as development of computer models for testing the method, diagnostic samples and designs. [ABSTRACT FROM AUTHOR]

Image formation in gamma-ray cameras is made by defining scintillation coordinates, produced by the absorption of gamma-quanta. By the present time different methods for scintillation coordinates defining have been developed based on previously measured and calculated amplitude-spatial features of a photodetector. The paper gives a method for estimating scintillation coordinates without any prior information. The method is based on approximation of the photodetecor response surface, located at the output window of permanent scintillation detector, on the scintillation light distribution function. For the approximation bicubic smoothing splines were used, which weight coefficients are set based on statistical features of measurement results. The paper proposes the approximation algorithm, taking into account geometry of photodetectors distribution at the output window of detector in the points of trigonal lattice. The algorithm can be applied in gamma cameras and other systems of gamma-rays imaging when using detectors such as gamma cameras. Relatively high computational intensiveness as compared to the Anger's method makes the proposed method more appropriate for off-line processing of accumulated data aimed at improving the image quality. [ABSTRACT FROM AUTHOR]