Relevance. 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. © 2025, National Academy of Sciences of the Republic of Kazakhstan. All rights reserved.

In the mining industry, when breaking rocks, oversized pieces are formed that exceed the dimensions of the technological equipment. To carry out secondary rock fragmentation in quarries, it is proposed to use an electromagnetic hammer. At the D.A. Kunayev Institute of Mining, a prototype of a mediumclass electromagnetic hammer with an impact energy of up to 6000 J has been developed. The use of the electromagnetic hammer for breaking oversized pieces in the mining industry will increase the efficiency, environmental friendliness, andautomation of the technological processes of rock and ore fragmentation. To develop a competitive prototype of a rock-breaking hammer, it is necessary to justify its dynamic parameters. A microprocessor-based measurement system was developed to measure the dynamic parameters of the prototype of the electromagnetic hammer, followed by the calculation of the energy characteristics of the prototype using the software “Matlab.” A digital sensor “HC-SR04” and a microprocessor controller “Arduino Mega 2560” were used to measure the height of the moving part of the electromagnetic hammer. To eliminate measurement errors, calculate the dynamics of the plunger’s velocity, acceleration and impact energy values, and plot the dependency graphs, the “Matlab” program version R2021b was used. Experiments were conducted by supplying the power voltage to the upper coil with a current value of 120 amperes, while the lower coils received the power voltage with current values of 70, 100, and 120 amperes. The data obtained, after processing in the “Matlab” software, allowed for the construction of dynamic parameter graphs for the prototype. The analysis of the graphs revealed the design flaws of this prototype, the elimination of which will improve the technological characteristics of new developments.

The objective of this study was to investigate the fundamental aspects of acrylic resin and zirconia nanoparticle interaction to analyze the optical properties and subsequent changes in refractive index with incremental loading of nanoparticles. Poly(methyl methacrylate) (PMMA) reinforced with zirconia nanoparticles were prepared by dip coating, spin coating and solvent casting techniques. An overall understanding of the polymer nanocomposite film has been achieved using the spectroscopic and morphological studies. The vital aspect of this whole study is to derive a simple yet an efficient nanocomposite film capable of imparting extraordinary optical properties. Within the limitations of this research a very crucial property of the material has been revealed. The RI as well as the optical transparency of the nanocomposite film has been steadily maintained with a significant increase of RI by the magnitude of 0.06 and ~100% light transmittance on incorporation of pure zirconia nanoparticles into PMMA matrix has been achieved. The best technique found was spin coating as it could yield thin films and better transparency and higher refractive index.

This study focuses on the chemical modification of the polysaccharides chitosan and gellan gum to produce water-soluble amphoteric polyelectrolytes. The modified polymers were used to stabilize gold nanospheres (AuNSs) and gold nanorods (AuNRs), whose structural and physicochemical properties were thoroughly characterized. The results confirmed successful polymer modification and effective stabilization of gold nanoparticles with suitable sizes and shapes for biomedical applications.

The current investigation endeavors to address the inadequate ductility and suboptimal gas barrier properties of poly(lactic acid) (PLA) by producing composites of PLA with functionalized mesoporous silica (PLA/0.6SPA-MPS-ACN) through the solution casting method. MCM-41 (MPS) mesoporous silica is synthesized from rice husk (RH) via the sol-gel method and modified with a biosurfactant, sucrose palmitate (SPA), and again functionalized with anthocyanin (ACN). This study investigates how nanofiller weight percentages affect PLA’s structural, morphological, thermomechanical, and barrier characteristics. BET analysis reveals a decrease in pore volume and surface area subsequent to the modification of MPS with SPA and ACN. The morphological analysis provides evidence of the uniform dispersion of filler within the PLA matrix at a loading of up to 5 wt %. The structural characteristics, thermal stability, and crystallization properties of PLA/0.6SPA-MPS-ACN composites are examined by using FTIR, XRD, TGA, and DSC analysis, respectively. All composite films have lower UV-visible light transmission than PLA. Mechanical investigations show that PLA/0.6SPA-MPS-ACN (5 wt %) films significantly improve tensile strength, yield stress, and tensile modulus values by ∼55, ∼88, and ∼89%, respectively. The OTR data show that adding 0.6SPA-MPS-ACN (5 wt %) to the PLA matrix reduced the O2 transmission rate by ∼52%. The Nielsen model fitted PLA composite diffusion data with a lower 0.6SPA-MPS-ACN loading.

Currently, one of the topical directions in the field of production and application of graphene-like nanostructures is the use of renewable natural raw materials, which have unlimited resources for an economically efficient large-scale yield of a product with environmental safety. In this regard, we present the production of graphene oxide (GO) from a renewable natural raw material of plant biomass, birch activated carbon (BAC), and a comparison of the obtained physicochemical, mechanical, and electrical properties of birch activated carbon–graphene oxide (BAC–GO) and graphite–graphene oxide (G–GO) synthesized from the initial materials, BAC and graphite (G). Results obtained from this study confirm the successful oxidation of BAC, which correlates well with the physical–chemical dates of the G–GO and BAC–GO samples. Change in data after the oxidation of graphite and BAC was facilitated by the structure of the starting materials and, presumably, the location and content of functional oxygen-containing groups in the G–GO and BAC–GO chains. Based on the results, the application of a cost-effective, eco-friendly colloidal solution of nanodispersed BAC–GO from a plant biomass-based high-quality resource for producing large-scale nanostructured graphene is validated which has potential applicability in nanoelectronics, medicine, and other fields.

This study investigates the use of gold nanospheres (AuNSs) and gold nanorods (AuNRs) as agents for photothermal therapy (PTT) in cancer treatment. The nanoparticles were synthesized and evaluated for their ability to convert light into heat and destroy cancer cells. Results showed that both AuNSs and AuNRs effectively damaged Ehrlich cancer cells, with AuNRs demonstrating slightly greater efficacy. In vivo experiments confirmed that laser irradiation of tumors after nanoparticle injection significantly reduced tumor size in mice.

The present study aims to advance the existing body of research on electrode materials used in electrochemical applications, specifically sustainable energy devices, such as solid oxide fuel cells (SOFCs). Synthesis and characterization of the Ce~0.8~Cu~0.1~Co~0.1~MnO~3~ electrocatalyst was performed, followed by analysis of the electrochemical properties of this complex oxide system. The electrocatalyst offers high activity in oxygen reactions at intermediate temperatures, and is considered to be a promising candidate for SOFCs that operate in such a range, as it shows significant improvement in catalytic activity. The structural and morphological features of Ce0.8Cu0.1Co0.1MnO3 have been examined using X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectroscopy, transmission electron microscopy and TEM analysis showed that particle size ranged from 40 nm to 80 nm. Brunauer-Emmett-Teller analysis showed that the calculated surface area of Ce-CCM was 196.1 m2/g, EIS demonstrated that at a temperature of 600 degrees, the current density was 1.1 W/cm2. This is 1.2 times higher than that of existing cathode materials. Further, the oxidation states and surface composition of the Cu and Co incorporated into the CeMnO3 matrix were confirmed through XPS analysis. The results point to the potential of this material being used as an electrocatalyst for efficient oxygen reactions in various energy harvesting devices.

This review explores different approaches for extracting low-esterified pectin from sugar beet pulp (SBP), a sustainable and often ignored by-product of sugar industry. Although traditional acid hydrolysis is commonly used, it has disadvantages such as varying yield and environmental concerns. Newer approaches—such as enzyme assisted extraction, ultrasound-assisted extraction, and microwave-assisted extraction—have shown promising results in improving efficiency and preserving pectin quality. Using enzyme, especially when combined with ultrasonic pre-treatment, has demonstrated effective in increasing yield and reducing processing time. SBP-derived pectin has unique structural characteristic, like high acetylation, which can affect its functional properties. Hybrid techniques and eco-friendly solvents are developing as valuable tools to overcome these limitations. This review highlights strengths and challenges of each method, underlining importance of optimizing conditions for industrial use. This review specifically examines SBP, an underexploited source of pectin, highlighting novel green extraction technologies, structural-function relationships, and commercial viability—areas not extensively addressed in prior reviews.

The use of plant extracts for the synthesis of metal nanoparticles represents a promising direction in nanotechnology due to the high environmental friendliness and cost-effectiveness of the method. In this study, green synthesis of silver nanoparticles was carried out using Hibiscus sabdariffa and Aloe vera extracts. The synthesis was conducted by reaction between the extracts with a silver nitrate solution, leading to the formation of silver nanoparticles. The synthesized nanoparticles were identified using UV-visible spectroscopy, scanning electron microscopy, particle size determination, and X-ray diffraction (XRD) analysis. The UV spectra exhibited characteristic absorption in the range of 350–450 nm, confirming the presence of silver nanoparticles, while XRD analysis determined an average particle size of 6.11 nm. The size analysis demonstrated the stability of the nanoparticles over time and their retention within the nanometer range. Comparative antibacterial tests demonstrated that AgNPs synthesized using H. sabdariffa extract showed higher inhibitory activity against E. coli and S. saprophyticus compared to those produced with A. vera extract. The obtained results confirm that biogenic synthesis using plant extracts is an environmentally safe and highly efficient alternative to conventional chemical methods, offering promising applications in biomedicine, catalysis, and other high-tech fields.