No 1 (2025)

The design of rotor blanks made of heat-resistant nickel alloys welded by a promising method — friction stir welding — has been analysed. The most characteristic types of defects, the occurrence of which is possible at this welding method, and their preferential orientation are demonstrated. For detection of such defects the scheme of diffraction method of control is offered. Its applicability on the sample with artificial and natural defects is shown.

This paper addresses the challenge in traditional laser ultrasonic methods, where the detection of surface defects in metal materials is often hindered by noise, and a novel approach that combines laser ultrasonics with Duffing oscillators to achieve a high signal-to-noise ratio for weak defect signals on metal surfaces is proposed. By leveraging the sensitivity of the Duffing oscillator’s chaotic system to initial conditions and its noise immunity, we can accurately identify the location of weak defects. Simulation results confirm the effectiveness and stability of this method for detecting surface defects in metal sheets.

Deterioration characteristics analysis and the estimation of the deterioration grade of textile relics are the premise of accurate restoration and protection. Therefore, in order to identify the deterioration characteristics of textile relics and develop a micro-non-destructive method for estimating the deterioration grade of textile relics, In this study, scanning electron microscopy (SEM), Fourier infrared spectroscopy (FTIR) and X-ray diffraction (XRD), which require very little sample, were was used to systematically investigate the degradation characteristics of textiles under different hydrolysis conditions, and based on this, a method suitable for estimating the degradation grade of precious textile relics was proposed. Results illustrated that regardless of textiles’ type, the more obvious the decline in appearance and mechanical properties, the more obvious the corresponding changes in infrared spectrum and X-ray diffraction, indicating that the changes at the molecular level in the molecular structure and crystallinity correlate well with the changes in the macroscopic properties such as appearance morphology and mechanical properties. Balancing the convenience of operation, the preciousness of textile relics and the quantification of results, the ratio of the strongest diffraction peak in X-ray diffraction detection as an evaluation index to estimate the degree of deterioration of textile relics was most reasonable and had potential for widespread use in predicting the deterioration of textile relics within collections. The study was not only useful to understand the degradation mechanisms that textiles undergo under moist burial environments, but also valuable to support the textile conservation tasks currently being performed in museums to preserve our heritage.

The article discusses a method for detecting PCB defects using neural networks. The analysis of various neural network architectures is carried out to identify the most effective. An approach to filtering data simulating the operation of a microtomograph using convolutional autoencoders is also presented. To assess the quality of the proposed approaches, the mean Average Precision (mAP) metric for the YOLOv8 and Faster R-CNN models was used.

The phase-sensitive laser thermography method is highly sensitive and allows you to control the uniformity and thickness of coatings made of various materials. The use of robotic manipulators as a scanning device allows you to carefully examine the surfaces of objects of complex shape in automatic mode. The article provides information about the layout of a robotic complex for laser phase-sensitive thermography based on a five-axis robotic arm, a laser with a power of up to 8 watts and a wavelength of 450 nm, as well as a COX CG640 thermal imager. Methods of processing experimental data for determining the thickness of coatings made of materials with low thermal conductivity are proposed. To test the approach, control samples were made of aluminum oxide coated with polypropylene in the range from 40 to 500 microns. It is established that the unevenness of the coating is rationally determined by the phase distribution of temperature fluctuations with a frequency of 0,1—1 Hz.