№ 10 (2025)

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 added voltage and the penetration depth of the electromagnetic field into the coating material at different excitation frequencies of the transducer is performed

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 boundaries for specimens of two steel classes (hull steel 20GN and maraging steel 08Kh15N5D2T) under their 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 hull steel 20GN monotonically changes 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 maraging steel 08Kh15N5D2T, multiparameter testing is recommended, which includes a combination of such parameters as critical field and residual induction

The transition from a surface forest fire to a crown fire was experimentally studied under laboratory conditions. Using non-contact 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

High-entropy alloy of the CoCrFeNiAl_x 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 estimation 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 the scanning devices