This research introduces an innovative ensemble approach, combining Deep Residual Networks (ResNets) and Bidirectional Gated Recurrent Units (BiGRU), augmented with an Attention Mechanism, for the classification of heart arrhythmias. The escalating prevalence of cardiovascular diseases necessitates advanced diagnostic tools to enhance accuracy and efficiency. The model leverages the deep hierarchical feature extraction capabilities of ResNets, which are adept at identifying intricate patterns within electrocardiogram (ECG) data, while BiGRU layers capture the temporal dynamics essential for understanding the sequential nature of ECG signals. The integration of an Attention Mechanism refines the model’s focus on critical segments of ECG data, ensuring a nuanced analysis that highlights the most informative features for arrhythmia classification. Evaluated on a comprehensive dataset of 12-lead ECG recordings, our ensemble model demonstrates superior performance in distinguishing between various types of arrhythmias, with an accuracy of 98.4%, a precision of 98.1%, a recall of 98%, and an F-score of 98%. This novel combination of convolutional and recurrent neural networks, supplemented by attention-driven mechanisms, advances automated ECG analysis, contributing significantly to healthcare’s machine learning applications and presenting a step forward in developing non-invasive, efficient, and reliable tools for early diagnosis and management of heart diseases. © 2024 Tech Science Press. All rights reserved.

The global concern regarding the disposal of municipal wastewater sludge is pressing. Contaminated water influxes into wastewater treatment channels, causing a surge in sludge volume and requiring additional processing. Pyrolysis of domestic wastewater sludge emerges as a promising solution, transforming waste sludge into reusable secondary raw materials. Our study employs a uniquely designed batch reactor system to uncover outcomes from laboratory-based thermal processing of domestic wastewater sludge. Within the reactor, the feedstock undergoes a series of processes, including dehydration, depolymerization, partial decomposition, and the removal of water. Additionally, decarboxylation occurs, leading to the formation of pyrolysis resins, achieved by combining dehydration and decarbonylation processes. This comprehensive process yields solid, liquid, and gaseous carbonaceous hydrocarbon residues. The chemical composition, structure, and properties of these pyrolysis products are thoroughly examined through analytical characterization techniques. Our findings reveal that sludge pyrolysis accomplishes thermal sterilization, resulting in valuable carbonaceous residue with potential applications as fuel or raw materials for petrochemical synthesis. Moreover, during pyrolysis, heavy metals such as cadmium and mercury can be extracted from the carbonaceous residue. Importantly, this process generates additional energy, and operating below 500 °C prevents dioxin contamination in the environment. © Engineered Science Publisher LLC 2023.

Ensuring water resources for livestock production in Kazakhstan presents a multifaceted challenge. Pastoral systems in Southern Kazakhstan are facing a critical groundwater shortage, with 56.5% of pastures currently unused due to limited water access, jeopardizing around 2 million head of livestock and the region’s food security. This study presents the first comprehensive groundwater assessment in over 40 years, integrating hydrochemical analysis (55 samples) and field surveys conducted in the Almaty and Zhetysu regions. Key findings include: the total water demand for livestock is estimated at 53,735 thousand m3/year, with approximately 40% of samples exceeding WHO guidelines for total mineralization. It was determined that 45% of exploitable groundwater reserves in the Almaty region and 15–17% in the Zhetysu region are suitable for irrigation. This study also provides updated hydrogeological data, identifying three priority aquifer systems. A novel Groundwater Sustainability Index for pastoral zones of Central Asia is introduced, demonstrating that strategic aquifer development could expand watered pastureland by 30–40%. These findings directly inform Kazakhstan’s Agricultural Development Plan through 2030 and provide a replicable framework for sustainable water management in arid regions. With 69,836 rural residents currently lacking access to safe water, our results underscore the urgent need for infrastructure investment to meet SDG 6 targets (ensure availability and sustainable management of water and sanitation for all). © 2025 by the authors.

Extreme ecosystems are a rich source of specialized metabolites that can overcome multidrug resistance. However, the low efficiency of traditional exploratory research in discovering new antibiotics remains a major limitation. We hypothesized that actinomycetes may have the ability to produce antibiotics in the extremes of a changing natural environment. This study introduces a novel approach to screening natural antibiotic producers from extreme habitats based on the relationship between organisms' adaptive traits and their metabolic activities. The antibacterial and antifungal properties of 667 actinomycete isolates, obtained from 160 samples of Kazakhstan's diverse extreme habitats, were studied under neutral, saline, and alkaline conditions against MRSA, E. coli, C. albicans, and A. niger. Among these isolates, 113 exhibited antibacterial properties, and 109 demonstrated antifungal properties. Notably, one-fifth of the antagonist isolates could produce active substances solely under extreme growth conditions. Fifty-three antagonistic actinomycetes, possessing these characteristics, have been categorized into groups and warrant further investigation as potential producers of new natural antibiotics. Molecular genetic analysis of the selected isolates revealed a high prevalence of Streptomyces and Nocardiopsis strains. Furthermore, 83.4 % of obtained isolates demonstrated the ability to thrive in all studied habitats—neutral, saline, and alkaline. 96.3 % of actinomycetes isolated from extreme environments exhibited adaptation to neutral conditions, highlighting their inherent versatility. Our findings underscore the nearly complete potential (99.7 %) of isolates to overcome the salinity barrier of 3.5 % NaCl, indicating their capacity to inhabit oceanic environments. We assert that actinomycetes should be perceived as a cohesive, globally adaptive group, capable of migrating between changing conditions or remaining stable within them. These studies lay the groundwork for the development of a new platform for screening natural antibiotics. © 2024 The Authors

Failure Modes, Effects, and Criticality Analysis are widely used to assess the failure modes of a system, along with their causes and effects. Several Multi-Criteria Decision-Making approaches have been developed to overcome the limitations of the traditional FMECA. In these approaches, several multiple criteria are considered to determine the criticality values and assign criticality ranks. In these developed approaches, only one expert can involve in criticality analysis. By incorporating several experts from design, manufacturing, and maintenance domains in the criticality analysis accuracy of the results can be improved. This paper proposes a new integrated Expert Judgment-based Preference Section Index (ExJ-PSI) model that combines MCDM approaches and integrates expert opinions. The proposed model is applied to a boiler system used in the textile industry. The results are compared with those obtained from the conventional FMECA and normalized median method. In the present study, the opinions of seven experts from various domains and organizations are discussed. To normalize the collected data, one scale is developed by considering four expert criteria, such as the experience of the expert, the number of boilers he is handling, the number of employees under his supervision, and the proficiency in the field. The proposed model is more effective and flexible in handling and analyzing data of complex configured systems consisting of many subsystems, components, and failure modes. The analysis reveals that the feed water pump, feed water pump motor, supply water temperature sensor, return water temperature sensor, header, and coal feed motor are some of the most critical components of the boiler system. © 2022 by the authors.

The industrial and environmental safety of mining at the Zhilandy group of deposits is ensured via identification and prediction of hazardous geodynamic processes and phenomena. This study used and integrated approach including: geological engineering of the structure and tectonics of rock mass with mapping of disturbed, displaced and crushed rock zones, instrumental surveying using electronic tachometer, surface monitoring of pit wall using ground scanning and UAV, examination of displacements at the points of a geodynamic testing area (GTA) points and assessment of the stress strain behavior changes in rock mass using satellite geodesy technologies. The methodology for integrated geodynamic monitoring is developed. The new method for GTA creation is proposed. The study results were implemented at existing mine within the R&D projects, namely, “Comprehensive monitoring of slow deformation processes of the earth’s surface during large-scale ore mining in Central Kazakhstan” and “Highly effective methodology for monitoring geotechnical conditions in rock mass to assess and predict deformation processes during mineral mining”, and also in the educational process at the Satbayev University. The implemented R&D resulted in creation and commissioning of: — the geodynamic testing area in the region; — the designs of permanent (ground and underground) forced centering points (FCP) allowing an increase in observation efficiency and accuracy; — the pit wall reinforcement method and the method of the stress–strain behavior prediction in rock mass; — the composition of the mine waste solution to reinforce the disturbed pit wall areas. The novelty of the developed methods and means is confirmed by the patents of invention of the Republic of Kazakhstan. The GTA creation at mineral deposits in Central Kazakhstan is a reliable framework for the long-term monitoring of the earth’s surface deformation during large-scale mineral mining, allowing the enhanced efficiency and accuracy of observations. The results obtained can be used to improve the level of industrial safety at mines and minimize the environmental risks caused by subsoil development. © 2024, Ore and Metals Publishing house. All rights reserved.

Zinc oxide (ZnO) and materials based on it are often used to create battery-type supercapacitor electrodes and are considered as promising materials for hybrid asymmetric supercapacitors. However, when creating such electrodes, it is necessary to take into account the instability and degradation of zinc oxide in aggressive environments with a non-neutral pH. To the best of our knowledge, studies of the changes in the properties of ZnO-containing electrodes in alkaline electrolytes have not been carried out. In this work, changes in the structure and properties of these electrodes under alkaline treatment were investigated using the example of ZnO-containing composites, which are often used for the manufacturing of supercapacitor electrodes. Supercapacitor electrodes made of two materials containing ZnO were studied: (i) a heterogeneous ZnO-Co3O4 system, and (ii) a hexagonal h-Zn-Co-O solid solution. A comparison was made between the structure and properties of these materials before and after in situ electrochemical oxidation in the process of measuring cyclic voltammetry and galvanostatic charge/discharge. It has been shown that the structure of both nanoparticles of the heterogeneous ZnO-Co3O4 system and the h-Zn-Co-O solid solution changes due to the dissolution of ZnO in the alkaline electrolyte 3.5 M KOH, with the short-term alkaline treatment producing cobalt and zinc hydroxides, and long-term exposure leading to electrochemical cyclic oxidation–reduction, forming cobalt oxide Co3O4. Since the resulting cobalt oxide nanoparticles are immobilized in the electrode structure, a considerable specific capacity of 446 F g−1 or 74.4 mA h g−1 is achieved at a mass loading of 0.0105 g. The fabricated hybrid capacitor showed a good electrochemical performance, with a series resistance of 0.2 Ohm and a capacitance retention of 87% after 10,000 cycles. © 2024 by the authors.

Atmospheric carbon dioxide (CO2) levels increased from 419.3 ppm (ppm) in 2023 to 425.4 ppm in 2024, 51 % above preindustrial levels, with emissions rising from 37.01 to 37.41 billion metric tons. This surge has driven record global temperatures, with annual mean surface temperatures reaching 1.45 °C and 1.55 °C above preindustrial averages in 2023 and 2024, intensifying glacial melt, sea-level rise, and extreme weather events. Photocatalytic CO2 reduction to methane (CH4) has emerged as a promising pathway to mitigate CO2 emissions while producing an energy carrier compatible with existing infrastructure. This review focuses on advancements in photocatalysts based on graphitic carbon nitride (g-C3N4) for photocatalytic CO2-to-CH4 conversion, offering a sustainability-centered perspective often overlooked in previous reviews. In addition to summarizing progress in dopant integration, heterojunction formation, and charge separation strategies, this work critically examines the environmental footprint of precursor materials and the energy consumption of thermal, microwave, and plasma-assisted synthesis methods. It highlights the potential of solar and LED light sources as scalable, energy-efficient alternatives to conventional lamps. The review also addresses practical challenges such as CO2 purification, impurity tolerance in exhaust-fed systems, and the feasibility of CH4 recovery and separation. Furthermore, it explores the integration of photocatalytic CO2 reduction with emerging approaches like direct air capture, electrocatalysis, biophotocatalysis, and computational tools including machine learning and multiphysics modeling. By aligning CH4 production performance with system-level sustainability criteria, this review establishes a framework to guide future developments toward environmentally viable photocatalytic CO2-to-CH4 technologies. © 2025 Elsevier B.V.

This study describes both experimental and numerical investigations into the heat and mass transfer processes governing the vacuum freeze drying of camel milk, with a specific focus on improving the energy efficiency. A three-dimensional model was developed and solved using the finite element method to simulate temperature evolution and sublimation interface progression during drying. The numerical model was validated against experimental data, achieving strong agreement, with an 𝑅2 value of 0.94. A detailed parametric analysis examined the effects of the shelf temperature, sample thickness, and chamber pressure on the drying kinetics and energy input. The results indicate that optimising these parameters can significantly reduce the energy consumption and processing time while maintaining product quality. Notably, reducing the sample thickness to 4 mm shortened the drying time by up to 40% and reduced the specific energy consumption (SEC) from 358 to 149 kWh/kg. These findings offer valuable insights for the design of more energy-efficient freeze drying systems, with implications for sustainable milk powder production and industrial-scale process optimisation.

The ground source heat pump heating system is considered as one of the best solutions for the transition towards green heating under the continental climate conditions like Kazakhstan. In this paper, experimental and theoretical investigations were carried out to develop a ground source heat pump-based heating system under the weather conditions in Kazakhstan and to evaluate its thermodynamic performance. The water-to-water heat pump heating system, integrated with a ground source heat exchanger and used refrigerant R134a, was designed to provide hot water to meet the requirements for space heating. The predicted values of the coefficient of performance and the experimental results were found to be in good agreement within 6.2%. The thermodynamic performance of the system was also assessed using various environment-friendly refrigerants, such as R152a, R450A, R513A, R1234yf and R1234ze, as potential replacements for R134a. Although R152a is found to be a good alternative for R134a in terms of coefficient of performance and total equivalent warming impact, its flammability hinders its application. The heating system using refrigerants R450A, R513A, R1234yf and R1234ze shows 2–3% lower coefficient of performance than that of R134a. The highest exergy destruction is found to be attributed to the compressor, followed by the expansion valve, evaporator, and condenser. Considering their low flammability and low environmental impact, R450A, R513A, R1234yf and R1234ze are identified as valuable replacements for R134a. © 2022 by the authors.