Russian Journal of Nondestructive Testing最新文献

Thin-sheet rolled low-carbon manganese steel 09G2S with a thickness of  0.8 mm which has strong property anisotropy due to texture and residual stresses, was experimentally studied using SH-wave with horizontal polarization and zero-order symmetric Lamb wave mode. The velocities of elastic wave propagation along the sheet were analyzed as their direction and polarization varied relative to the rolling direction in the range of angles from 0° to 180°. The excitation and reception of normal waves in the sheet were carried out by piezoelectric transducers with dry point contact, providing tangential force application. The results of the research on the anisotropy of acoustic properties, X-ray structural analysis of residual stresses and inverse pole figures, and metallographic studies were obtained.

Correctly identifying precious wood species is crucial for import and export trade and furniture material identification. This study utilizes nondestructive testing (microscopic computed tomography, Micro-CT) to capture microscopic images of the transverse, radial, and tangential sections of 24 precious wood species, creating a comprehensive dataset. The SLConNet deep learning model is developed, enhancing recognition accuracy through multi-scale convolution and an improved residual block structure. The experiment results show that the classification accuracy of the transverse, radial and tangential sections is 98.72, 96.75, and 95.36%, respectively, when the gain value is 0.8. The model outperforms traditional models like Alexnet, ResNet50, Inception-V3, and Xception. This research highlights the efficiency of nondestructive testing in obtaining a large number of microscopic wood images, compared to traditional anatomical methods. The SLConNet model showcases high accuracy in precision, recall, and specificity, suggesting its potential for widespread applications in wood classification.

In the automotive industry, sheet metal products are generally shaped by deep drawing process. Especially after the deep drawing process of stainless-steel sheet metal products, fine splits or surface cracks occur in the tensile and compressive strain regions. The reason for this situation can be given as the errors in the mold, the mechanical properties of the sheet metal varying according to the producing company, and the difference of this property in different parts of the sheet roll. If a deformed and pre-inspected sheet metal is mounted on an automobile, painted, and then put into a drying oven, all defects in the sheet metal will become evident as it expands under high temperature. Detecting defects at this stage increases the cost. Accordingly, in this study, a new real-time optical inspection system based on multiple photosensitive resistors (LDRs) was developed for crack detection in the automotive industry. In this system, a light source is placed on the inside of the crankcase cover in a dark, light-proof environment. Then, LDR sensors are placed around the outside of the cover to detect the level of light leaking out of the cover. At the same time, the environment was monitored with a camera, and image processing was performed with OpenCV. The collected data was sent to a cloud database server in JSON format over Wi-Fi with NodeMCU and recorded. Finally, the results of the experiment were analyzed with a WebGL-based web interface developed using Unity and visualized on a crankcase cover model drawn with Solid Works. The researcher can visually see the manufacturing defects and dimensions in the 3D environment on the model. It was determined that the system can identify the crack in a crankcase cover shaped by the deep drawing process and verify it with the camera within 6 s.

Sulfur exhibits an unusual dependence of viscosity on temperature. An experimental setup was developed to study the viscosity of sulfur at pressures up to 100 bar and temperatures up to 500°C. Proton radiography was used to visualize the movement of a tungsten carbide ball placed in liquid sulfur. The experiment was conducted using the PRIOR II proton microscope (GSI Helmholtz Centre for Heavy Ion Research, Darmstadt, Germany). In this experiment, the SIS-18 accelerator operating mode with slow beam extraction was used for proton radiography for the first time. The viscosity of liquid sulfur was measured at a pressure of 90 bar and temperatures ranging from 190 to 320°C. It has been shown that impurities, including hydrogen sulfide, which appears in the sulfur melt at high temperatures, have a significant effect on the viscosity of sulfur.

As an important connection type, threaded connections are very easily damaged by cracks on the threaded surfaces during the production and service period, which would lead to mechanical failure. The complicated geometry of threaded connections brings great challenges to conventional non-destructive testing (NDT) methods. Thus, it is important to develop an advanced and suitable NDT technology to detect cracks on threaded surfaces. This study investigates the applicability of electromagnetic thermography (ET) for crack inspection. The inspection principle was examined based on electromagnetic and thermal conduction laws. Experiments were conducted on four bolts with cracks on their threaded surfaces using ET technology. The effectiveness of ET was verified through the analysis of thermograms and temperature responses. In addition, we also study the influence of several key parameters, including excitation coil orientation, excitation coil location, the amplitude of excitation current, and crack size, on the detection results. The findings indicate that ET offers an efficient and practical method for inspecting cracks on threaded surfaces.

In ultrasonic flaw detection, lateral cylindrical drilling is traditionally used to adjust and check equipment parameters. Other volumetric reflectors such as vertical drilling or spherical pores are rarely used. In this article, it is noted that volumetric reflectors of various types are convenient for use as a model of internal and surface defects of welds. Moreover, drillings of various orientations are easy to manufacture. For a long time, the limitations on using drilling for modeling in ultrasonic nondestructive testing were related to the noise caused by diffraction effects as elastic waves bypass cylindrical cavities. It is noted that these effects are currently well studied. They can be used to identify the type of defects and measure their size. The present paper describes the results of experiments on the observation of scattering of longitudinal and transverse waves with various polarization by cylinders and spheres and provides typical examples of the manifestation and use of these diffraction effects. The expediency of using not only drilling but also spherical pores is also noted. Experiments with scattering of ultrasonic waves by pores were performed on transparent glass samples for clarity. Comparative data are presented showing how diffraction effects manifest themselves on various volumetric cavities. In particular, it is noted that a focusing of signals that envelope spherical pores is observed. Limitations on the pulse duration of ultrasonic waves are noted in which diffraction signals can be used to increase information content in the detection of defects. It is recommended to expand the use of lateral drilling with a diameter of 2 mm in samples to adjust sensitivity during ultrasonic monitoring with an echometer.

We studied magnetic phase transitions near the Curie temperature in the ferrite material with the composition ({text{N}}{{{text{i}}}_{{0.4}}}{text{Z}}{{{text{n}}}_{{0.6}}}{text{F}}{{{text{e}}}_{2}}{{{text{O}}}_{4}}) using thermomagnetometric analysis and methods for recording the temperature dependences of initial magnetic permeability ({{mu }_{0}}left( T right)) and specific electrical resistivity (rho left( T right)). The study provides a description of the equipment used and the key features of the experimental methods under consideration. During thermomagnetometric analysis in the cooling phase, it has been found that the temperature at which the material completes its transition to the ferrimagnetic state corresponds to the inflection point on the ({{mu }_{0}}left( T right)) curve and the break point on the (ln rho left( T right)) dependence graph. The established interaction between the parameters of transition processes may be useful for more accurate determination of the Curie temperature in ferrites.

Coronavirus disease (COVID-19) or C-19 is caused by the SARS-CoV-2 virus. Most people infected with the virus will experience mild to moderate respiratory symptoms and will recover without requiring specific treatment. COVID-19 has increased the need for accurate diagnosis, prompting researchers to create more advanced and efficient detection technologies. Currently, many investigations are being conducted, including reverse transcription PCR tests, chest radiographs, ultrasound scans, and CT scans. They are best conducted later in the illness phase when sensitivity and specificity are max. In this work, the adaptive normalization and enhancement (ANE) technique is proposed for pre-processing. It normalizes pixel intensity values, enhances contrast, and reduces variability in image quality. Deep convolutional feature mapping (DCFM) is employed to automatically learn and extract comprehensive features in pre-processed CT scans. Finally, hybrid ensemble learning model (HELM) is proposed to increase the accuracy and reliability of COVID-19 and Pneumonia identification, resulting in better patient outcomes and more effective pandemic management.

The interaction of burning and smoldering particles with forest combustible materials, followed by their impact on certain types of combustible building materials and wood-based structures, has been experimentally investigated. Thermal flux values generated by smoldering particles were obtained, and the temperature field of the most thermally stressed areas of the tested structures was analyzed using noncontact IR diagnostic methods within narrow spectral ranges of infrared wavelengths. In the infrared range, the surface emission of the samples was recorded using a JADE J530SB thermal imager equipped with an optical filter for the 2.5–2.7 μm range; this enabled temperature measurements in the range of 310–1500 K. Calibration data provided by the manufacturer of the narrowband optical filter were used to interpret the recorded emissions from the tested samples.

The paper presents the results of studying the evolution of magnetic characteristics of a two-layer material consisting of layers of annealed sheet low-carbon steel grade 15 and sheet metastable austenitic steel grade 12Kh18N9T differing in magnetic hardness subjected to cold rolling with a reduction of 50% under biaxial symmetric tension. Experiments on biaxial deformation were performed on an original biaxial testing machine that allows determining the physical properties of materials during elastic-plastic deformation independently along two axes. It is shown that the coercive force of the studied two-layer material, monotonically changing over the entire range of elastic-plastic biaxial deformation, can be used as an informative parameter for assessing stresses and strains.