This study presents a numerical and experimental investigation of the thermal performance of borehole heat exchangers for ground source heat pump systems. A 3D model was developed for heat and mass transfer in soil and grout, coupled with 1D conductive and convective heat transfer through the pipe and circulating fluid. The model was implemented in COMSOL Multiphysics and validated using thermal response test data obtained from two 50 m-deep boreholes drilled in the Almaty region of Kazakhstan. The root-mean-square deviation between model predictions and TRT data was 0.184°C. The thermal conductivity of the soil (λg = 2.35W/mK) and thermal resistance (Rb = 0.20mK/W) were determined. Simulation results showed that spiral borehole heat exchangers provided the highest heat extraction and reduced drilling depth by 34.6% compared to single U-type. The model aids in optimizing borehole heat exchanger geometry and evaluating material properties for enhanced thermal efficiency. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.

The pressing issue of global warming, coupled with the increasing depletion of fossil fuels, highlights the necessity for sustainable energy solutions. In this context, hydrogen stands out as a viable option, possessing the capacity to revolutionize critical industries, including fuel cells, internal combustion engines, and gas turbines. An effective approach to enhancing numerous chemical and technological processes in liquid and steam–gas mixtures is the establishment of cavitation mixing zones for the reacting components. These zones are produced in specialized reactors that operate on the principles of hydrodynamic effects applied to the reaction medium. The study focused on the design of the cavitation-jet chamber utilizing the k– (Formula presented.) Turbulence Model and Particle Tracing Model. As a result, the influence of the inlet velocity on cavitation formation and the uniformity of mixing was investigated. Ripley’s K-function was used to analyze the results of particle distribution. The influence of the screw on flow turbulence and the uniformity of particles was evaluated. Analysis through the K-function indicated a decrease in uniformity at lower velocities, with noticeable turbulization of the flow occurring at high velocities, which facilitated better mixing. In contrast, without the screw, the flow exhibited a high longitudinal velocity and minimal transverse velocity, limiting particle dispersion to the radius of the nozzle and resulting in inefficient mixing. It was found that the inclusion of the screw not only enhanced particle distribution but also maintained the size of the cavitation zones, thereby improving the overall efficiency of the design.

The article discusses the improvement of methods of tracing transport networks in the context of optimal planning of cities and settlements. It is necessary to provide a systematic approach to planning. The development of the master plan considers the division of the territory into traditional functional zones. Functional zones are modeled in the form of circles and rectangles. Then these zones are divided into separate subsets. Objects located inside functional zones are modeled by points, and objects connecting these points by straight lines. Network tracing is achieved by constructing an orthogonal Steiner network taking into account the weight coefficients of the functional zones. Orthogonal or Euclidean Steiner networks are constructed in subsets. The construction of a network and pedestrian roads inside the functional zones is being carried out. When solving this problem, the calculation of the need for transport is also provided. Optimization of the transport network tracing is as follows: for a given set of points, it is required to determine the number and optimal location of additional points, so that the total length of the network is minimal. The shortest path to the points is determined. Optimization geometric models are an effective and visual means of developing various options for tracing the network between functional zones and within zones. From several network tracing options, a network that meets the pre-set planning requirements is selected. Allows you to analyze and make the right decision in determining the promising direction of development and construction of a city or settlement. © 2023 K. A. Kuspekov.

Problems with increasing heavy metal contents in natural waters are becoming a global issue. At the same time, improved methods for water treatment are becoming increasingly important. In this context, natural zeolites can be used to purify polluted water. In this paper, we investigated how the adsorption capacity of natural zeolites can be improved. Natural zeolites from the Shankanay district, Almaty, Kazakhstan, were used as adsorbent material for experiments on improving the water treatment of heavy metals. We found that the adsorption capacity for heavy metals was increased greatly by thermal activation using furnace treatment. The optimal thermal activation condition was about 550 °C for a duration of 2 h. However, the improved adsorption capacity for different heavy metals varied depending on the heat treatment temperature. Adsorption by the heat-treated zeolites at a temperature of 550 °C was 87% for nickel, 99% for copper and cadmium, and 100% for lead. Adsorption by heat-treated zeolites at a temperature of 500 °C was 78% for nickel, 98% for copper, 83% for cadmium, and 88% for lead. The residual concentration of heavy metals in the filtered water did not exceed the maximum permissible concentrations for drinking purposes. In all experiments, intense adsorption took place during the first 10 min representing 35 to 61% of the metal ions in the water. Adsorption properties were verified using adsorption capacity (BET), IR spectroscopy, and scanning electron microscopy. The study shows that modified Shankanay natural zeolites have great potential as a low-cost adsorbent material for purifying water from heavy metals. © 2023 by the authors.

The paper contains the laboratory study results for the flotation processing of gold-containing tailings with the use of the composite reagent (CF). The CF flotation reagent is a microemulsion from a composition of sodium butyl xanthate and reaflot. A gold-containing concentrate was obtained with a gold content of 6,7 g/t with a recovery of 59,71 % in the basic mode. The use of the CF composite flotation reagent increases the gold extraction into the gold-containing concentrate by 3,77 %, as compared with the main collector-sodium butyl xanthate. The con-sumption of CF flotation reagent is reduced by 20 %. © 2022, Faculty of Metallurgy. All rights reserved.

Anthropogenic CO2 emissions are a major driver of climate change, highlighting the urgent need for effective mitigation strategies. Carbon Capture, Utilization, and Storage (CCUS) offers a promising approach, particularly through CO2-enhanced gas recovery (EGR) in shale reservoirs, which enables simultaneous hydrocarbon production and CO2 sequestration. This study employs a numerical simulation model to compare two injection strategies: CO2 flooding and huff-and-puff (H&P). The results indicate that, without accounting for key mechanisms such as adsorption and molecular diffusion, CO2 H&P provides minimal improvement in methane recovery. When adsorption is included, methane recovery increases by 9%, with 14% of the injected CO2 stored over 40 years. Incorporating diffusion enhances recovery by 19%, although with limited storage potential. In contrast, CO2 flooding improves methane production by 26% and retains up to 94% of the injected CO2. Higher storage efficiency is observed in reservoirs with high porosity and low permeability, particularly in nano-scale pore systems. Overall, CO2 H&P may be a viable EGR option when adsorption and diffusion are considered, while CO2 flooding demonstrates greater effectiveness for both enhanced gas recovery and long-term CO2 storage in shale formations. © 2025 by the authors.

The bottom sediment of reservoirs has many functions. Among them, matter sorption is a very important one, and results in many side-effects on the reservoir sediment forming the water–bottom sediment system. As a result, bottom sediment can also be an indicator of anthropogenic water pollution. There is only very little knowledge of this situation in the study area. The main objective was the analysis of heavy metal accumulation in bottom sediment, as well as their ability to migrate throughout the water–bottom sediment system and their spatial distribution in the Kapshagay Reservoir in Kazakhstan. Heavy metal concentrations, in the both water samples and the bottom sediment, were determined using the atomic absorption spectrophotometric method. Surfer software was used to visualize the processes of migration and accumulation. Another objective was the development of model maps of the spatial distribution of metals in the reservoir water area, which indicated significant anthropogenic loads. It is obvious that both the transboundary inflow of the Ili River and the inflow from small rivers in the territory of Kazakhstan are the reasons for the anthropogenic water and sediment load. The results of the spectrometric analysis verify the water pollution in the reservoir, revealing increased concentrations of zinc reaching up to 10.8 µg/L and lead up to 32.7 µg/L, transported by the transboundary runoff of the Ili River and by the small rivers on the left bank into the Kapshagay Reservoir. Sediment concentrations close to the central part and dam zone of the reservoir reached the following values: zinc up to 37.0 mg/kg and lead up to 8.8 mg/kg. The results of this study indicate a significant anthropogenic load of the ecological conditions of the Kapshagay Reservoir. This is discussed and compared with other relevant studies. © 2022 by the authors.

In this work, optical properties of perovskite solar cells (PSCs) with planar and nanorod-based SnO2 electron transport layers (ETLs) are studied and their photovoltaic parameters are compared using computer simulation methods. It is found that nanorod-based SnO2 ETLs improve the light harvesting ability of device. However, their power conversion efficiencies (PCEs) are still lower than those with thin planar SnO2 ETLs. © 2023 IEEE.

This study aims to enhance terrorism financing detection mechanisms by analyzing existing patterns in financial transactions. Utilizing advanced data analysis techniques and machine learning models, we identified significant transaction patterns indicative of terrorism financing activities. The proposed models demonstrated improved accuracy and efficiency over traditional detection methods. The findings have substantial implications for financial institutions and regulatory bodies in strengthening financial security and preventing illicit activities. © 2024 IEEE.

Herein, a comprehensive validation of the catalytic and sensing capabilities of gallium sulfide (GaS). This study focuses on the self-assembled heterostructure formed by GaS with its native oxide, revealing novel insights into the crucial role of defects, strain, and surface oxide phases in optimizing the behavior of 2D materials for catalytic and sensing applications. Although the energy barrier for water dissociation on pristine GaS surfaces is prohibitive (+419.3 kJ mol−1), surface sulfur vacancies considerably reduce this barrier, transforming defective GaS (GaSx) into an efficient catalyst for the hydrogen evolution reaction (HER) in alkaline media. Water dissociation is energetically favorable at room temperature on GaS0.96 surfaces (−147.6 kJ mol−1). Correspondingly, the differential free energy for HER on GaS0.96 in an alkaline medium is found to be −1.56 eV for the hydroxyl adsorption step and +1.28 eV for the desorption step, while all reaction steps are exothermic for its implementation as a catalyst for oxygen evolution reaction (OER). These theoretical models and surface-science experiments confirm that exposure of GaS surfaces to ambient conditions leads to the inevitable formation of a self-assembled nanoscale (≈3 nm thick) oxide skin. This native oxide layer stabilizes the surface and, moreover, it also significantly enhances its catalytic and sensing properties by providing additional active sites and improving charge transfer dynamics. The exceptional sensitivity (response of 18% at T = 150 °C) and selectivity for detecting ammonia (NH3) are attributed to both its high affinity for chemisorption and the significant charge-transfer interactions that enhance the sensor response.