CC BY
0Dynamic speckle diagnostics of irreversible processes in biological
and technical objects
A. Vladimirov1'2'3*
1-E.S. Gorkunov Institute of Engineering Science of the Ural Branch of the Russian Academy of Sciences, 34 Komsomolskaya str., Yekaterinburg, 620219, Russia 2- Ural Federal University named after B.N. Yeltsin, 19 Mira str., Yekaterinburg, 620002, Russia 3- FSRIVI "Virome" Rospotrebnadzor, 23 Letnaya str., Yekaterinburg, 620039, Russia
* vap52@bk.ru
The purpose of the report is to review the research conducted by the author over the past 5 years on the application of a new optical method. The method makes it possible to determine dynamic deformations caused by changes in the shape and volume of gas, liquid and solid bodies with a spatial resolution of Al of the order of 1 ^m. The subjects of our research are intracellular processes in cultured cells, high-cycle fatigue of materials and turbulent flows. The relevance of these studies is related to the absence of methods that allow real-time monitoring of intracellular processes, assessing the accumulation of fatigue damage, and determining the parameters of turbulent flows. The results obtained earlier can be found in the chapters of the books [1,2]. In these publications, the theoretical, experimental and metrological justification of the time-averaged speckle image method was given. It was shown that the parameter characterizing the intensity of metabolic processes, as well as the accumulation of fatigue damage to materials, is the standard deviation c of the difference in the optical paths Au of pairs of waves propagating at a characteristic distance of Al. In the articles [3,4], the theory of the method was further developed. The problem of speckle dynamics in the image plane of a transparent and reflective object, respectively, was solved under the assumption that the random variable Au is the sum of independent quantities Aum, m=1,2,...M. These values correspond to processes occurring simultaneously in different layers of transparent or at different scale levels of reflective objects. A tomographic method for determining the mean values, variances c2 and correlation (relaxation) time xm of Aum, as well as two simple methods for determining cm(xm) dependencies, was substantiated. These dependences characterize the relative contribution of processes occurring at different speeds to cellular metabolism, fatigue degradation of materials and to the turbulent flow of liquids and gases. An excellent coincidence of theory and experiment was obtained (Fig.1).
The method has been successfully used to identify the nature of high-cycle fatigue of materials. It is shown that the key point of low-, high- and giga-cycle fatigue is the localization of irreversible processes in small zones and the appearance of areas that are constantly in a tensile state as a result. In these areas, cyclic creep first occurs, followed by deformation softening of the material, leading to the formation of a macro-fracture. To assess the life of the parts, the creation of devices and methods of non-destructive testing of a new generation based on the use of matrix-type sensors with cell sizes of the order of 10 microns is justified. Dependences cm(xm) are given for cultured cells in normal conditions and with the introduction of toxic substances, as well as for the turbulent flow of heated air.
Fig.1. The normalized ACF of radiation intensity fluctuations in the image plane of a group of cells [3]. Theory and experiment.
[1] A. Vladimirov and A. Bakharev, Dynamic speckle interferometry of thin biological objects: theory, experiments, and practical perspectives, In book: Optical Interferometry (Intech), Chapter 6 (2017).
[2] A. Vladimirov, Dynamic speckle interferometry of technical and biological objects, In book: Interferometry (Intech), Chapter, (2018).
[3] A. Vladimirov, Speckle tomography of the living-cell functions, Radiophysics and Quantum Electronics, Vol. 63 (8), pp. 592-604, (2021).
[4] A. Vladimirov, N. Drukarenko Yu. Mikhailenko, Speckle diagnosis of irreversible processes occurring in some living and technical objects, In book: Optical Flow Research Methods (Pero Publishing House), pp. 51-62, in Russian, (2021).
