Centrifugal pumps are widely used in various industries such as manufacturing, agriculture and firefighting due to their versatility. They are based on the principle of creating centrifugal force by a rotating impeller, which ensures the movement of liquid from the suction point to the discharge point. Design methods are based on the theory of one-dimensional homogeneous flows and hydraulic laws. This study focuses on designing impellers for centrifugal pumps with the aim of creating an efficient design that meets performance and head requirements. To achieve this, fundamental principles of fluid mechanics and empirical equations for one-dimensional flows are utilized. The culmination of the work is the study and analysis of various methods for calculating the hydraulic characteristics of centrifugal pumps, which helps to identify their advantages and limitations and select the most suitable method for a particular task. Efficient application of such methods simplifies and speeds up the pump design process, enabling engineers to develop new models and improve existing ones more quickly.

This study investigates the impact of widely used mineral fillers in self-compacting concrete compositions applied in vibration-free reinforced concrete production technology, as a means of enhancing rheological characteristics and cost-effectiveness. Three distinct types of mineral fillers, including the well-studied fillers microsilica and metakaolin, as well as the lesser-explored filler Kazakhstani natural opal-chalcedony opoka, are examined in this research. In addition to the evaluation of conventional rheological and performance properties of concretes containing these fillers, the internal processes within the cement–filler matrix are analyzed. This includes X-ray phase analysis and microstructural examination of cement hydration products in combination with a superplasticizer and each of the three minerals. The findings confirm the potential for optimizing the rheological parameters of the concrete mixture by substituting up to 15% of the cement with mineral fillers, achieving optimal viscosity and workability. It is established that compositions with the addition of microsilica and metakaolin have a more homogeneous structure, mainly represented by low-basicity calcium hydrosilicates of the CSH(B) type, along with an increase in compressive strength of up to 10%. The addition of these mineral fillers to C30/35 strength class self-compacting concrete resulted in improved frost resistance up to F300, a reduction in volumetric water absorption by up to 30%, and a decrease in shrinkage deformations by 32%. The developed SCC compositions have successfully passed production testing and are recommended for implementation in the operational processes of reinforced concrete product manufacturing plants. © 2025 by the authors.

The disposal of drilling mud waste from uranium mining operations poses a significant environmental challenge due to their toxicity and potential for contamination. The investigation aims to test different powder flocculants of approximately the same molecular weight and their interaction with waste drilling mud and to identify the flocculant with the best qualities for further use in the industry. The empirical method was applied in the study, during which experiments were carried out on a sample of drilling mud, along with quantitative and statistical analyses. Flocculation was carried out using a Couette cylindrical flocculator. Three flocculants, namely A-150, N-100, N-300, and C-494, from a single manufacturer, Kemira, were also chosen for the study. As a result of the laboratory experiments, it was determined that N-300 was the best flocculant, giving optimum results in the study. It has been found to be capable of separating the drilling mud into water and solids fractions as quickly as possible. In addition, the use of ultra-flocculent treatment to improve the intensity of the sedimentation process of clay suspensions is a prerequisite. Thus, the drilling fluids treated in this way are more environmentally friendly, increase productivity and duration, and reduce production costs. The novelty lies in systematically evaluating various powder flocculants and applying ultraflocculation, a sophisticated hydrodynamic treatment method, to optimize the separation process.

This study explores sustainable groundwater management in semi-arid southeastern Kazakhstan, focusing on the feasibility of managed aquifer recharge (MAR) at the Lepsinsky experimental site in the Almaty Region. With surface water resources declining due to climate change and human activity, MAR presents a promising solution for water-scarce areas. Researchers constructed an infiltration trench 650 meters from the Lepsy River and established a temporary hydrological monitoring station to assess infiltration dynamics and colmatation processes. Hydrogeological assessments included lithological analysis, infiltration testing, and turbidity monitoring. Results indicated favorable infiltration conditions, with filtration coefficients ranging from 0.11 to 4.32 m/day depending on sediment composition. Volumetric moisture tracking showed full saturation within 50–72 hours, confirming effective percolation. Turbidity levels remained acceptable, and portable turbidity meters closely aligned with standard methods (R = 0.90). The findings support MAR implementation at the Lepsinsky site, particularly for decentralized rural and agricultural water supply systems. The study offers a replicable framework for designing and optimizing recharge systems in similar environments, contributing to future groundwater sustainability and infrastructure planning in arid regions. © The Author(s) 2025.

The paper presents the results obtained during the study of seismicity of the Kazakh shield based on the data from seismic stations of the Institute of Geophysical Researches of Kazakhstan which are a part of the international monitoring systems. Emphasis has been placed on seismic activation in 2016–2018 in the middle part of the Central Kazakhstan arch, previously considered aseismic. The earthquake focal mechanisms determined for 40 seismic events recorded in the investigated area are based on the displacement directions of the first arriving P waves. On the basis of the analysis of the earthquake focal mechanism data set, an assessment has been made of the present- day stress-strain state of the Earth’s crust of the low-seismicity Kazakh shield. It is shown that a system of stresses in the investigated area is characterized by conditions for near-horizontal compression whose direction is consistent with the direction of movement of the Alpine geomorphostructures. It has been found that the earthquake sources in the investi gated area are dominated by reverse faults and reverse-slip faults which correspond structurally to the northeast-striking and submeridional tectonic faults, thus testifying to present-day seismic activation of the northeastern thrusts. This study allowed for concluding that the seismic events considered are human-induced, i.e. technogenic-tectonic, earthquakes. A long-term technogenic impact reducing the strength of rocks in fault zones can be a cause of critical stress drop in earthquake sources located in the Kazakh shield. The data on the character of motions and stresses in the earth quake sources influencing on shaking intensity will be used in combination with other methods for the assessment of natural and technogenic hazards related to geodynamic processes

Despite the promising specific discharge capacity and energy density, lithium-sulfur batteries (LSBs) encounter challenges related to the lithium polysulfides (LiPSs) shuttle effect and volume expansion during extended cycling. A pivotal aspect of this research lies in the strategic synthesis of a hybrid of non-polar and polar compounds, creating an effective host and separator modifier tailored for LSBs for improvement of their electrochemical characteristics. Precisely, high-specific surface area graphene-like porous carbon (GPC) was successfully synthesized from inexpensive and abundant rice husk (RH) waste via step-by-step carbonization and thermo-chemical activation, and subsequently used as a porous matrix for sulfur cathode preparation using the melt-diffusion technique. Furthermore, composites based on GPC decorated with NiO nanoparticles were synthesized with varying GPC to Ni(NO3)2 ratios and utilized as an efficient separator modifier. The obtained results revealed that the cell consisting of GPC@S cathode and GPC-NiO-20 modified separator exhibited accelerated LiPSs redox reactions and suppressed the shuttle effect. In particular, the GPC@S/GPC-NiO-20 cell demonstrated excellent initial discharge capacity (1519 mAh g−1 at 0.2 C), promising long-term cycling performance (capacity decay of 0.091 % per cycle over 400 cycles at 1 C), and remarkable rate performance (568 mAh g−1 at 2 C). © 2023 Elsevier B.V.

This study investigates the hydrogen adsorption performance of activated carbon (AC) derived from rice husks and modified with magnesium and nickel salts. Adsorption isotherms were recorded at 25 °C and 50 °C up to 80 bar, simulating practical storage conditions. The unmodified AC exhibited the highest hydrogen uptake (0.62 wt% at 25 °C), attributed to its high surface area and dominant ultramicroporosity (<0.9 nm). Modifications with Mg and Ni reduced adsorption capacity, likely due to partial pore blockage and decreased surface functionality, as confirmed by FTIR, Raman, and XRD analyses. Despite this, all samples demonstrated stable cyclic adsorption–desorption behavior and consistent isotherm profiles. Hysteresis observed in the modified samples suggests capillary condensation within mesopores. Thermodynamic analysis confirmed the exothermic nature of hydrogen adsorption. Among the modified materials, ACM10 (Mg-modified) exhibited the best performance (0.54 wt%), highlighting the importance of optimizing the metal content. The obtained results indicate that the micropore size distribution and accessible surface functionality critically govern the hydrogen storage capacity, suggesting that unmodified AC is a promising candidate for low-temperature hydrogen storage systems. © 2025 by the authors.

The B10 fuel blend in the presence (or absence) of n-butyl alcohol and eucalyptus essential oil additivities by the ASTM standards has been tested. As seen our results, these oxygenated compounds can be successfully used in B10 fuel blends as additives to improve exploitation properties. Methanol-based biodiesel has been synthesized by the transesterification reaction of technical cottonseed oil in the presence of potassium hydroxide, with a maximum yield of 64% at a molar ratio of oil to alcohol of 1:3, at 65°C. The oxidizing stability of the B10 fuel blends with (or without) additivities has been evaluated using the NMR spectroscopy method. Our experimental results demonstrated that investigated B10 fuel blend with oxygenated compounds has a high potential for diesel engines than B100 and petroleum diesel. The best results demonstrate the B10+n-Butanol fuel blend.

Purpose. The research is aimed at developing the technology for chemical strengthening of mine workings using epoxy reagent to create a protective shield in unstable zones of rock masses, as well as at assessing the strength of the strengthened areas and improving the stability of mine workings. Methods. During the research, core samples extracted from the epoxy reagent-strengthened mass were tested to assess their strength and resistance to external influences. Numerical modeling was performed in ANSYS Mechanical 14.5 to analyze the stress-strain state of strengthened and non-strengthened areas. Findings. Tests of core samples taken from the Akbakai mine showed that failure mainly occurs in the zones of contact between the rock and the adhesive composition, with the share of new fractures not exceeding 15%. The adhesion strength was 0.15 MPa, which is three times higher than that of non-strengthened rock. The results of modeling confirmed the reduction of stresses and displacements in strengthened zones by 2-3 times compared to non-strengthened ones, which indicates the high efficiency of the proposed method to improve the stability of mine workings. Originality. For the first time, an innovative method of chemical strengthening of mine workings with the use of protective epoxy shield, which significantly increases the stability of the mass when conducting mine workings under the influence of mineral salts and external loads, has been substantiated. Practical implications. The developed technology of chemical strengthening of mine workings with the use of protective epoxy shield has a high practical significance for the mining industry. Its application will significantly improve the stability of rock masses, especially in unstable zones exposed to the influence of mineral salts, which contributes to improving the safety and durability of mine workings, reducing the risks of caving and cleavage, as well as increasing the efficiency of miningtunneling operations. © 2025. Y. Iskakov, D. Amanzholov, Z. Kenessov.

Climate warming and intensified human activities threaten the stability of oasis ecosystems in arid regions, increasing water resource pressure and vegetation degradation. Existing methods fail to fully capture hydrological-vegetation interactions, and research on groundwater depth thresholds remains limited. The Keriya River, which extends deep into the heart of the Taklamakan Desert, serves as a crucial window into the water balance between humans and oases. This study, using multi-temporal Sentinel-2 remote sensing imagery, water resource observation data, and ground survey data from 2016–2024, extracted data on farmland area and watershed area in the middle and lower reaches of the Keriya River over multiple years. An analytical framework integrating remote sensing monitoring, machine learning, and groundwater modeling was constructed to systematically assess the impact of regional farmland expansion on groundwater dynamics and desert riparian forests. Results revealed farmland increased by 31.17 km² year−1. Due to the increase in human water use in the middle reaches, decreasing groundwater levels by 0.04–0.05 m year−1 and straining ecological water supplies. Populus euphratica forest decreased by 4.04 km² year−1, while drought-resistant Tamarix chinensis communities expanded by 3.67 km² year−1, indicating a shift to secondary vegetation. Spatial variations in the fractional vegetation cover indicated a significant decline in vegetation health along the oasis peripheries, with pronounced degradation trends in areas with insufficient surface water supply. Model projections indicate that, if current trends persist, 34.5 % of the total oasis area will have groundwater levels shallower than 6 m by 2120, i.e., below the groundwater level suitable for the growth of desert riparian forests. This would put the oasis ecosystem at risk of large-scale degradation, resulting in long-term and irreversible impacts on protected areas. The methodology improved spatiotemporal resolution, quantitative simulation, and multi-source process integration and provides a novel pathway for investigating hydrological-ecological dynamics in arid regions and scientific evidence for water resource management and ecological conservation. Controlled farmland expansion, improve the legal and regulatory standards system, optimized water usage, and a long-term ecological water supplementation mechanism are recommended to sustain the oasis ecosystem. © 2025 The Authors