An indirect-drive cryogenic target is a hollow spherical shell-capsule with a solid layer of hydrogen isotopes (fuel) on its inner surface, located in a box-converter, which in turn is mounted in a cryostat to provide for operation at a cryogenic temperature. Before placing a target in an ignition experiment at a megajoule energy level facility, a thorough characterization of all component elements of the target and of the finished target must be completed. This paper describes three-dimensional modelling of a visible radiation beam propagation through a cryogenic target to study the robustness of optical shadow method for characterization of a solid fuel layer in an optically transparent shell in the presence of harmonic perturbations of various orders and amplitudes of the shell and fuel layer surfaces, as well as under nonideal experimental conditions.

The transition from a surface forest fire to a crown fire was experimentally studied under laboratory conditions. Using noncontact infrared (IR) diagnostic methods within narrow spectral ranges of infrared wavelengths, the propagation speed of the fire front was determined, along with temperature changes at control points where the combustion transitions from a surface fire to a crown fire. The experiment was conducted under varying incoming airflow velocities and different canopy heights relative to the surface fire. In the infrared range, the radiation from the sample surfaces was recorded using a JADE J530SB thermal imaging camera equipped with an optical filter (2.5–2.7 μm), enabling temperature measurements within the range of 310–1500 K. To interpret the recorded radiation from the test samples, calibration data provided by the manufacturer of the narrowband optical filter was used.

To address the challenge of accurately quantifying surface crack depth in additively manufactured components, a novel method based on the mode conversion of laser ultrasonic surface waves is proposed. By analyzing the propagation paths and time-domain signal characteristics of mode-converted surface waves (RSR waves) at the crack location, a quantitative model relating crack depth to time is established. Finite element simulations are employed to investigate the mode conversion and propagation mechanisms of surface waves, and a non-contact laser ultrasonic testing system is developed accordingly. An optimized C-VMD algorithm is further proposed to extract the characteristic signals effectively. Experimental results demonstrate that the proposed method achieves a quantitative detection error of less than 4% for cracks with depths ranging from 0.6 mm to 1.4 mm, indicating its suitability for detecting small-sized cracks in metal additive manufacturing components.

The paper presents a study on the application of the Jiles–Atherton magnetic hysteresis mathematical model. The optimal model parameters were selected based on measurement data in a closed-loop magnetic circuit and used to build digital models in COMSOL Multiphysics. Experimental studies on ferromagnetic steel samples with different magnetic properties demonstrated good agreement with the design data. The results showed that the deviation of the experimental values of the key characteristics (Bmax, Br, Hc) from the simulation results did not exceed 5%. Detailed pictures of the spatial distribution of magnetic induction and field strength in samples in different parts of the magnetic hysteresis loop were obtained. The verified model will allow further optimization of the designs of magnetizing devices and the location of sensors when developing new methods and means of magnetic nondestructive testing.

Measurements using eddy current transducers in a wide frequency range are considered. Resonance properties have been investigated, hodographs of transducer signals have been constructed depending on the signal frequency and the thickness of the electrically conductive coating on an electrically conductive nonmagnetic base, and the phase method of detuning from the gap for different signal frequencies is considered. A comparative analysis of the dependencies of the amplitude of the insertion voltage and the penetration depth of the electromagnetic field into the coating material at different excitation frequencies of the transducer is performed.

The results of experimental studies on detection of defects such as cracks and impact damages in glass-reinforced plastic pump compressor pipes (GRP PCP) and glass-reinforced plastic sucker rods (GRP SR) using a thermal nondestructive testing method involving combined ultrasonic and optical stimulation are presented. It is demonstrated that ultrasonic infrared thermographic testing is appropriate for detecting cracks, especially “kissing” ones, whereas traditional thermal inspection based on optical heating is more suitable for identifying delamination and thinning. The efficiency of the inspection depends on the size of the ultrasonic stimulation zone with sufficient power (approximately 0.8 m in this study). During optical heating procedures, the testing productivity depends on the size of the heated area and the field of view of the thermal imager and can reach several square meters per hour.

During the service period, pipelines are prone to various factors causing damages such as holes and cracks. This paper takes 20# steel pipelines as the research object, setting time-domain amplitude, spectral amplitude and power spectral density as quantitative indicators, to study the response characteristics of the longitudinal mode of guided waves to different damages under different excitation frequencies, explore the sensitivity of the longitudinal mode of guided waves to pipeline damages and analyze the applicable excitation frequencies. The results show that the longitudinal mode of the guided wave is most sensitive to circumferential cracks, and has the weakest sensitivity to longitudinal cracks. Therefore, it is not applicable for the detection of longitudinal crack damage. Furthermore, the longitudinal guided wave mode excited at 70 and 90 kHz exhibits high sensitivity to pipeline damage, making it well-suited for its detection. The frequency selection method proposed in this study, which is based on multi-index comparison, shows broad applicability and serves as a valuable reference for the detection of damage in pipeline structures.

The paper presents results of studying the behavior of the critical field parameter determined by the shape of the major magnetic hysteresis loop in the region of predominant displacements of 90-degree domain walls for specimens of two steel classes (20GN hull steel and 08Kh15N5D2T maraging steel) under plastic tensile deformations to various levels. The sensitivities of this parameter and other magnetic characteristics to changes in the stress-strain state of the studied steels are compared. It is established that the coercive force and the critical field of 20GN hull steel change monotonically in the entire range of plastic strain, while the sensitivity of the critical field to the value of strain is 4.8 times greater than the sensitivity of the coercive force. It has been shown that for assessing the state of products made of 08Kh15N5D2T maraging steel, a multiparameter testing is recommended that includes a combination of such parameters as critical field and residual induction.

High-entropy alloy of the CoCrFeNiAlx system (x = 0.3, 0.6, 0.8, 1.0) was obtained by powder sintering. The influence of homogenization temperature (900, 1000, and 1100°C) on microstructure, phase composition, microhardness, and magnetic properties of the alloy was investigated. It was found that microhardness, saturation magnetization, and maximum magnetic permeability increase with increasing homogenization temperature. The changes in magnetic characteristics correlate with the phase composition. The results obtained confirm the possibility of using magnetic methods to evaluate structural changes in high-entropy alloys of this system.

The paper describes a practically implemented method for correcting the geometrical aberrations introduced by a scanning device as a proposed stage of the computer radiography system qualification. The presence of geometrical distortions in the scanned images affects the metrological characteristics of the measurement methods and techniques that are using these systems. The method allows for correction of a systematic error obtained when scanning photostimulable phosphor detectors on the digital radiography devices. The main stages of method implementation include fabrication of the calibration sample, conducting reference instrumental measurements, comparing reference measurements with digital image processing results, and estimating and correcting the errors. During the period 2022 to 2024, the examination results for three scanning devices were analyzed. The use of the geometrical aberration correction method allows for minimization of distortions as well as estimation of quality and stability of scanning devices.