Acoustic emission systems and complexes are currently considered a sensitive method for detecting forming defects. However, defect detection in selective laser melting of heat-resistant alloys using acoustic emission becomes challenging under the influence of noise. The impact of noise significantly complicates the identification of factors influencing the defect formation process, and it also makes it much harder to interpret the parameters of acoustic emission that characterize the state of the object under control. Objective. Study of filtering methods in case of extraneous influences to improve the reliability of the results of recording acoustic signals and improve the identification process. Methods. This article presents the results of the implementation of the developed method of cascade digital filtering. The method is based on high-frequency digital filters, approximated by a second-order Butterworth polynomial model. Amplitude, time, and frequency fragments of acoustic emission signals, which characterize the defect formation process during the manufacturing of products, are highlighted. A relationship between the measurements of the signal’s amplitude parameters, the laser power of the system, and the nitrogen content in the heat-resistant alloy is established. The dependence of the laser power and nitrogen content percentage is approximated using the least squares method and visualized based on a scatter plot. Results and conclusions. The developed relationship describes and characterizes the influence of the listed factors on the defect formation process, and its adequacy is confirmed by calculating the coefficients of determination and significance. It is shown that the application of the cascade filtering method for signal identification significantly increases the effectiveness of the acoustic emission method. The developed cascade filtering method can also be applied when studying the acoustic properties and stresses caused by the physical fields of various rocks.

Polysaccharides such as chitosan (Ch) and gellan gum (GG) were chemically modified to produce water–soluble amphoteric polyelectrolytes. These derivatives were synthesized via carboxymethylation and quaternization reactions and characterized using techniques including 1H NMR, FTIR spectroscopies, elemental analysis, potentiometric titration, and thermogravimetric analysis (TGA). The degree of quaternization of gellan gum (QGG) with trimethylammonium groups was determined to be ~38% as by 1H NMR spectroscopy; ~35% based on potentiometric titration, and ~39% according to elemental analysis. Similarly, the degree of carboxymethylation of chitosan (CMCh) was calculated as ~37% according to 1H NMR data, while back potentiometric titration provided a value of ~35%. The modified polysaccharides exhibited distinct isoelectric points (pHIEP) as determined through electrophoretic mobility measurements and conventional viscometric analysis. The data collected from both techniques were in good agreement indicating pHIEP = 2.0–2.5 for the modified gellan gum and pHIEP = 7.0 for the modified chitosan. Amphoteric Ch and GG were used to stabilize spherical (AuNSs) and rod-like (AuNRs) gold nanoparticles, synthesized using “one-pot” and seed-growth methods, respectively. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) confirmed particle binding to the modified polymers. The average diameters of AuNSs stabilized with QGG and CMCh were ~45 and 85 nm, respectively, whereas AuNRs stabilized by QGG and CMCh exhibited dimensions of ~50–55 nm (length) and ~12–14 nm (width). These findings suggest that amphoteric QGG and CMCh-stabilized AuNSs and AuNRs could potentially be used as effective photothermal agents for treating Ehrlich cancer cells, as previously reported by our research group (Macromolecular Chemistry and Physics, 2024, 2400128).

Large volume changes, the insulating nature of sulfur, and the lithium polysulfides (LiPSs) shuttle effect significantly hinder the practical application of lithium-sulfur (Li-S) batteries. In this study, reduced graphene oxide/MXene (rGO/MXene) composites were investigated as potential sulfur host materials. Since the rGO-to-MXene ratio influences electrical conductivity, LiPSs confinement, and structural stability, MXene contents of 10 wt%, 20 wt%, and 30 wt% were systematically evaluated. The (rGO/MXene10)_S60 electrode exhibited the most promising performance, delivering an initial discharge capacity of 981 mAh/g and retaining 606 mAh/g after 100 cycles with Coulombic efficiency (CE) above 97 %. These results demonstrate that a 9:1 rGO-to-MXene ratio optimally enhances conductivity, structural stability, and LiPSs anchoring, making it a promising sulfur host for Li-S batteries.

This paper examines the integration of artificial intelligence (AI) in ankle rehabilitation exoskeletons. Special attention is given to modern AI technologies such as machine learning algorithms, adaptive control systems, neural networks, and data analysis, which significantly enhance the effectiveness and personalization of rehabilitation. Exoskeletons equipped with these technologies are capable of more precise motion tracking, adapting treatment in real time, and predicting patient movements, making rehabilitation safer and more comfortable. In addition to a comprehensive review of existing solutions, this study presents an AI-based ankle rehabilitation exoskeleton prototype developed as part of our research. The prototype integrates AI-driven adaptive control methods and sensor-based movement analysis to enhance rehabilitation efficiency.

The object of the study is the design, manufacturing technology and methods of stabilizing the electrophysical characteristics of measuring transducers. The problem solved in the research is the creation of methods and design and technological solutions to ensure stability used in the development and manufacture of measuring transducers. As a result of the conducted research, designs and technologies for manufacturing and stabilizing the electrophysical characteristics of measuring transducers were developed. The features of the developed designs of measuring transducers are increased in comparison with the known time stability with a basic error of no more than 0.1 %/year. Technologies for stabilizing the parameters of measuring transducers, in contrast to the known ones, differ in their versatility, since most elastic elements that perceive mechanical magnitude are membranes and beams, on which thermocompensating films are easily applied. The stabilization of the parameters of the entire measuring transducer, unlike the known ones, is carried out after the removal of internal mechanical stresses of each element and part of the measuring transducer through the integrated use of current and vibration dynamic loads. Thus, the use of complex compensation due to the application of a new method of compensation of internal mechanical stresses in the structure, based on the use of multilayer film compositions formed on sensitive elements, followed by thermal and vibration stabilization of measuring transducers. In addition, reducing the measurement error and increasing the time and parametric stability of the measuring transducers is achieved through the use of specialized heat treatment modes, training resonant vibration and current loads. When developing structures and stabilization methods, previously developed engineering mathematical models were used, including constructive, informational, dimensional, technological and circuit engineering. At the same time, depending on the adopted design and the technology used, engineering models were modified by including known coefficients and dependencies. This method has significantly reduced the cost and complexity of development

Central Asia regions are characterized by active tectonics, high mountain chains with extreme topography with glaciers, and strong seasonal rainfall events. These key predisposing factors make large landslides a serious natu- ral threat in the area, causing several casualties every year. The mountain crests are divided by wide lenticular or nar- row, linear intermountain tectonic depressions, which are in- cised by many of the most important Central Asia rivers and are also subject to major seasonal river flood hazard. This multi-hazard combination is a source of potential damming scenarios, which can bring cascading effects with devastat- ing consequences for the surrounding settlements and popu- lation. Different hazards can only be managed with a multi- hazard approach coherent within the different countries, as suggested by the requirements of the Sendai Framework for Disaster Risk Reduction.

The great interest in nanostructured magnetic composites is due to their great prospects for use as a basis for the development of catalysts for the adsorption of manganese in wastewater. Interest in magnetic nanocomposites in this direction is primarily due to the possibility of extracting them from water media using ordinary magnets, which allows them to be used again. Additionally, it is worthwhile to note interest in research related to increasing the efficiency of adsorption, as well as an increase in the number of repeated cycles of operation. In this regard, the main goal of this study is to study the prospects for applying the method of mechanochemical synthesis for the creation of iron-containing nanocomposites doped by rare-earth elements Gd, Ce, Y, and Nd in order to obtain optimal catalysts for cleaning water media. During the studies, structural properties and phase composition of synthesized nanocomposites were established, as well as ultra-thin parameters of the magnetic field. It has been established that the kinetic curves of the adsorption process can be described by a pseudo-first-order model, and the process of manganese adsorption itself is associated with the cationic interaction of manganese ions with the surface of nanocomposites. The kinetic curves of degradation were determined, as well as the influence of the number of cyclic tests on the adsorption of manganese for synthesized nanocomposites, depending on the type of dopant and phase composition, respectively. Iron-containing nanocomposites doped with gadolinium and neodymium have been found to have the highest adsorption efficiency and corrosion resistance. Particular attention is paid to the study of the stability of storage of nanocomposites for a long time, as well as the preservation of their adsorbent properties in the purification of aqueous media. It has been determined that the modification of nanostructures with the help of rare earth compounds leads to an increase in resistance to degradation, as well as to the preservation of the efficiency of adsorption for 5–7 cycles in comparison with Fe2O3 nanoparticles, for which low resistance to degradation was observed.

The aim of the study is to substantiate the parameters of technology and equipment for the manufacture of building products using alumina sludge from stone processing as an alumina aggregate. The standard methods of setting up an experiment for laboratory washing of granular sludge from stone processing and studying its physical and mechanical characteristics, manufacturing laboratory samples of polystyrene concrete blocks with further study of their strength characteristics were used. The physical and mechanical characteristics of granular man-made material - sludge waste from the stone processing industry - were experimentally determined. The possibility of using man-made sludge in the manufacture of polystyrene concrete blocks was substantiated by its particle size distribution and mineralogical composition. Average samples of granular material were deslagged using the TurboWash unit. The particle size distribution of the material after washing was analysed. According to the standard technology, recipe and raw materials for D300 polystyrene concrete, polystyrene concrete blocks of standard sizes of three grades were produced. Primary sludge without preliminary processing, sand and dusty loess obtained from the processing of primary sludge were used as an aggregate. The numerical values of the axial compression resistance for the studied grades of polystyrene concrete blocks were determined. © Published under licence by IOP Publishing Ltd.

The paper is devoted to the development of new equipment for the production of metal-polymer thread. 3D printing with metal-polymer thread is one of the advanced directions in the technology of manufacturing metal parts of complex shape. The proposed technology is an alternative to the currently existing metal injection molding (MIM) technology and selective laser melting printing technology. An important step in this work was to conduct computational experiments to determine the effect of screw rotation on the process pressure parameter and the design of the main assembly of the screw extruder. As a result of the research, the pressures on the metal-polymer composition were determined depending on the rotation speed of the screw. With a rotation of 30 rpm, the pressure reached 0.05 Pa and the maximum pressure was 0.18 MPa. The experiments were carried out in the CradelSFlow program. The computer calculation showed a margin of the screw strength coefficient k=1.8, and a maximum deflection of 2.8∙10–4 m, which meets the condition of static rigidity. To determine the correct value of the gap δ between the screw ridge and the extruder walls, an analysis of the rotor dynamics was carried out. The result of this study is the critical extruder rotation speed of 60 rpm at which the phenomenon of precession may occur.

Hydrogen Obtaining From The System Activated Aluminum-Water