Relevance. Operation of solid municipal waste landfills leads to soil degradation and a decrease in its fertility. Studying the impact of heavy metals on the ecology of landfill soils and soils of adjacent territories is important, since the accumulation of high concentrations of heavy metals can lead to disruption of the ecological and agricultural functions of the soil. Aim. To assess the contamination of soils by heavy metals at the solid municipal waste landfill in the city of Rostov-on-Don. Objects. The studied soil samples taken from the center of the landfill were compared to soils of the adjacent territory at different distances and directions relative to the center of the landfill. Methods. Gross contents of heavy metals and metalloids (V, Cr, Co, Ni, Cu, Zn, As, Sr, Pb, Rb, Zr, Ba) were studied using the X-ray fluorescence method. The obtained values were used to calculate the pollution indices: background enrichment coefficient, individual unified pollution index, geoaccumulation index, pollution load index, Nemerov pollution index, potential ecological risk index, pollution protection index, pollution probability index, and general pollution degree index. These indicators were used to determine the pollution degree of the studied territories. Results: The excess of Cr, Ni, Cu, Zn, As and Pb according to the MAC at the landfill from the control was determined. A very high concentration of heavy metals and metalloids compared to the MAC and background was found in the center and close to the center of the landfill, indicating the anthropogenic contribution of these elements. The evaluation of the results showed that the pollution load index is more reliable for assessing the pollution of the landfill and the adjacent territory with heavy metals. When compared, the used indices and pollution coefficients formed the following series: pollution load index>general pollution degree index>Nemerov pollution index>pollution probability index>pollution protection index>potential ecological risk index=background enrichment coefficient. The adjacent territory of the landfill was polluted to a lesser extent. The applied indices and coefficients can be used in environmental assessment, as well as in monitoring and for preventing soil pollution with heavy metals and metalloids. For citation: Kucherova A.V., Minnikova T.V., Kolesnikov S.I., Sherstnev A.K. Assessment of heavy metal pollution of soils of a municipal solid waste landfill of the city of Rostov-on-Don. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering, 2026, vol. 337, no. 8, pp. 90–101. http://doi.org/10.18799/24131830/2026/8/5062
Relevance. This article addresses the problem of improving the reliability and accuracy of sorting timber conveyors with a chain load-bearing element equipped with a variable-frequency asynchronous electric drive. An increase in the length of the working section of an extended timber-sorting conveyor leads to a rise in the mass of moving parts, a stronger influence of the viscoelastic properties of the chain, and greater complexity of transient processes during start-up. As a result, dynamic jerks, wave-like tension fluctuations, and misalignment in the displacement of individual chain sections occur, which reduces equipment durability and impairs the precision of timber delivery to storage bins. The relevance of this study is determined by the need to maintain the design service life of the load-bearing chain (belt) as a key structural element. Aim. To investigate the motion dynamics of chain-type and belt-type sorting conveyors in order to establish the boundary conditions for the operation of the load-bearing section. Results and Conclusions. It has been established that the most hazardous operating mode is rapid conveyor start-up without mechanical vibration damping. The use of a fluid coupling reduces the initial tension peak and proves most effective during short start-ups (up to 10 s), as it smooths abrupt changes in the drive torque and diminishes the intensity of the initial tension wave. However, for extended conveyors, the action of a single fluid coupling is insufficient: in the region of the reflected wave at the end of the load-bearing chain, the systematic error in timber positioning may remain at an unacceptable level. The implementation of an S-shaped ramp function reduces the jerk at the initial start-up stage and, at the final stage, limits tension oscillations while maintaining acceptable sorting performance. To achieve the ultimate sorting accuracy on long conveyors, it is advisable to employ a closed-loop electric drive control system with displacement sensors for timber on the load-bearing chain and wireless data transmission; however, the implementation of such a solution would be technically complex and capital-intensive. The optimal outcome of applying a refined model of the mechanical part of an extended sorting conveyor to reduce excessive oscillations under the climatic conditions of Western and Central Siberia is achieved through coordinated control of the traction variable-speed electric drive in conjunction with an adjustable fluid coupling. For citation: Kladiev S.N., Sarbassova N.D., Umurzakova A.D., Odnokopylov G.I. Mathematical models of sorting conveyors with belt and chain carriers. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering, 2026, vol. 337, no. 8, pp. 153–167. http://doi.org/10.18799/24131830/2026/8/5753
Relevance. The use of distributed fiber-optic temperature sensors in oil production wells can improve the quality of data obtained during operation. Aim. To show that the captured temperature distribution contains random fluctuations, the magnitude of which is comparable to the magnitude of thermoanomalies caused by the filtration flow of oil in the reservoir. Methods. To reduce the noise of the original signal taken from a real oil well, various approximation methods: median smoothing, moving average, exponential smoothing, Fourier filtering, decision tree, random forest, adaptive boosting and Nadaraya–Watson kernel regression method, were analyzed. Results and conclusions. The authors analyzed the results of application of these types of signal post-processing in terms of the following parameters: accuracy of approximation of equilibrium geothermal distribution in the well sump, where analytical determination of temperature distribution is possible, smoothness of the approximating function, uniqueness of the solution and demandingness of computational resources. It is shown that the application of adaptive boosting and Fourier filtering for this problem gives the largest approximation errors. Median smoothing, exponential smoothing and random forest give similar results in accuracy and low computational costs. The first does not have smoothness of solution. The second one depends to a large extent on the tuning parameters and the obtained solution may be either noisy as well, or the smooth solution may exhibit systematic error caused by random deviations of the initial points. Such error can be compensated by additional averaging at the initial stages of exponential smoothing. The random forest approximation is also tuning dependent, and regions of overfitting where the approximation replicates the original signal may be adjacent to a very coarse approximation of the original signal; this always produces a new approximation at each generation. The best results were obtained by the Nadaraya–Watson kernel regression method, since the solution found has the lowest error, high smoothness and uniqueness, in contrast to machine learning methods. On the basis of analyzing the features of the algorithm of this method, as well as the machine representation of real numbers, we propose methods to improve the computational efficiency of the Nadaraya–Watson kernel regression. For citation: Nikulin I.L., Mishurinskikh S.V., Chudinov P.Yu., Semenov A.S., Melekhin A.A., Nikulina D.I. Approximation and noise reduction in oil well thermometry by distributed fiber optic sensors. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering, 2026, vol. 337, no. 8, pp. 77–89. http://doi.org/10.18799/24131830/2026/8/5054
Relevance. Utilization of associated petroleum gas at remote and offshore fields remains an unresolved problem due to the lack of cost‑effective small‑scale technologies. Associated petroleum gas flaring causes environmental damage and leads to the loss of valuable hydrocarbon feedstock. Gas‑to‑liquids technology enables the conversion of associated petroleum gas into synthetic liquid hydrocarbons suitable for blending with crude oil or for use as motor fuels. However, known GTL processes require complex catalytic systems and separate regeneration of components, which limits their application in field conditions. Aim. To develop a single‑stage gas-to-liquid process for producing synthetic liquid hydrocarbons from synthesis gas obtained by non‑catalytic oxidative conversion of associated petroleum gas using polyfunctional catalysts, and to substantiate the design of a two‑section reactor that allows separating regeneration of catalytic components without stopping the main production. Methods. Seven bifunctional catalysts based on Zn, Cu and Al oxides were synthesized. The optimal Zn‑Cu/Al₂O₃ sample (ZnO 25.10 wt %, CuO 64.86 wt %, Al₂O₃ 10.04 wt %) was mixed with a pentasil‑group zeolite catalyst (SiO₂/Al₂O₃=47). Experiments were carried out on a laboratory flow unit with a fixed catalyst bed by varying the synthesis gas composition (H₂/CO≈0.93 and 2.03). Based on the identified technical contradiction (deactivation of the oxide catalyst during zeolite regeneration), a two‑section reactor was designed to be placed in a 20‑ft sea container. Strength calculations were performed. Results and conclusions. It was experimentally found that the maximum hydrocarbon yield (2.14 g/h) at a CO conversion of 29.1% is achieved with a feed having H₂/CO≈0.93, which corresponds to the composition of synthesis gas from non‑catalytic partial oxidation of associated petroleum gas with air. The proposed two‑section reactor allows oxidative regeneration of the zeolite‑containing catalyst in one section without stopping the hydrocarbon synthesis in the other section. The reactor block is scalable from 10 to 40 million m³ of associated petroleum gas per year by simply increasing the number of container modules. The developed polyfunctional catalytic system Zn‑Cu/Al₂O₃ + high‑silica pentasil is effective for single‑stage production of gasoline‑range hydrocarbons from synthesis gas with a low H₂/CO ratio. The two‑section reactor removes the limitations associated with separate catalyst regeneration and is a key element of the containerized “Heat – Electricity – Synthetic hydrocarbons” gas-to-liquid unit. The technical solutions are protected by a patent and can be recommended for pilot‑industrial implementation at remote oil and gas fields. For citation: Buslaev G.V., Kuzmin A.M., Malova O.V., Lishchiner I.I., Boreiko D.A., Innovative two-section reactor and catalysts for synthetic liquid hydrocarbon production at the GTL “HES” unit from synthesis gas of non-catalytic oxidative conversion of associated petroleum gas. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering, 2026, vol. 337, no. 8, pp. 45–56. http://doi.org/10.18799/24131830/2026/8/5696
In 2022–2024, it was officially established that unconventional renewable energy sources (wind turbines and solar panels) in the foreseeable future (15–20 years) will not be able to replace traditional energy (thermal and nuclear power plants) due to the lack of powerful, reliable and safe electric energy storage systems. Therefore, coal-fired power plants in the coming decades will certainly generate large amounts of electricity not only in China, India, the USA and Poland, but also in many other countries. In this regard, the world-class scientific problem is environmental pollution by coal combustion products (flue gases from coal-fired power plants). This problem can be solved by burning coal in the furnaces of steam and hot water boilers mixed with biomass (wood in the first place). But wood burning in the furnaces of boiler installations so far in most real technologies leads to intensive slagging of heating surfaces. Therefore, an urgent task, the solution of which can ensure the transition to environmentally friendly and resource-saving coal-fired power in the future, is the task of substantiating the parameters of ignition and combustion of wood biomass particles. Aim. To determine the combustion modes of wood biomass particles of different sizes during high-temperature heating. Object. Wood particles (pine) of cubic shape of three characteristic sizes. Method. To determine the ignition and combustion modes of cubic wood particles under high-temperature heating conditions, a special experimental setup with laser illumination was used. Results. A conventional temperature boundary of Tcr=908 K was established for the transition between two ignition modes (gas-phase and heterogeneous) for pine wood biomass particles. It was also shown that the characteristic particle size of the wood (in the studied size range, L=4–8 mm) has no significant effect on the characteristics and conditions of the transition from one ignition mode to another. It was also experimentally established that, at relatively low oxidizer temperatures, the difference in ignition delay times for different ignition modes with a characteristic particle size of L=8 mm can reach 10%. For citation: Baranova (Kostoreva) A.A., Syrodoy S.V., Solodovnikova (Kostoreva) Zh.A., Omarov A.A., Nekrasov S.S., Senchikhin D.K. Oxidizer temperature effect on the modes of ignition of wood biomass particles. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering, 2026, vol. 337, no. 8, pp. 32–44. http://doi.org/10.18799/24131830/2026/8/5436
