This paper presents a structural-parametric synthesis of the four-bar and Stephenson II, Stephenson III six-bar function generating linkages. Four-bar linkage is formed by connecting two coordinate systems with given angles of rotation using a negative closing kinematic chain (CKC) of the RR type. Six-bar linkages are formed by connecting two coordinate systems using two CKCs: a passive CKC of the RRR type and a negative CKC of the RR type. The negative CKC of the RR type imposes one geometrical constraint to the relative motion of the links, and its geometric parameters are defined by least-square approximation. Passive CKC of the RRR type does not impose a geometrical constraint, and the geometric parameters of its links are varied.

The material and phase composition of manganese ore–processing waste from the Altyn-Shoko deposit were comprehensively analyzed, and the optimal conditions for producing phosphating solutions from this technogenic material were established. Phosphate coatings formed on St3 carbon steel using these synthesized solutions were evaluated using gravimetric corrosion tests, electrochemical measurements, and Scanning Electron Microscopy (SEM) – Energy-Dispersive X-ray Spectroscopy (EDS) analyses. Mechanical activation of the waste, intended to break down mineral aggregates, increased the phosphoric acid leaching efficiency at 25 °C from 66.9% to 72.9% but simultaneously reduced the free H3PO4 content in the solution. Although this treatment improved dissolution, it also accelerated sludge formation during phosphating and decreased the corrosion resistance of the resulting coatings. In contrast, phosphating solutions prepared from non-activated waste produced uniform, dense, and compact phosphate layers composed of iron, calcium, manganese, and phosphorus compounds, yielding superior protective performance. Coatings derived from mechanically activated waste were more porous and consisted mainly of iron–calcium–phosphate phases, which correlated with their reduced barrier properties. Overall, the results demonstrate the potential of Altyn-Shoko beneficiation waste as a sustainable feedstock for low-cost phosphating solutions while highlighting the limitations introduced by mechanical activation.

According to the CONPrint3D concepts, in order to improve the reliability of machine technology and expand the scope of 3D concrete printing, the printing system will be integrated into the truck-mounted concrete pump, which has the problem of insufficient positioning accuracy of the printhead. This article discusses a manipulator for compensation and positioning of the printhead from deflections of the boom of a truck-mounted concrete pump used as a construction 3D printing manipulator. The manipulator must compensate for the workspace X ±300, Y ±300, Z ±250x mm (X – length, Y – width, Z – height). To solve these problems, a comprehensive literature review of manipulators (serial, parallel, and hybrid) was carried out. Manipulators were sorted according to several criteria: degree of freedom, number of actuators, leg designs; and workspace and overall dimensions. Inverse kinematic problems are solved to determine the workspace and dimensions of the manipulators. Clavel's delta robot was selected among the manipulators, and the direct and inverse kinematics problems were solved. To understand and predict the behavior of Clavel's delta robot, a virtual experiment was made using dynamic modeling with the OpenModelica program.

Obtaining new knowledge about the beneficiation of lead-rich oxidized lead-zinc ores attracts wide interest of researchers in the field of mineral processing due to extremely rich reserves of resources and complexity of lead and zinc extraction. The objective of this study is to analyze the mineralogical characteristics of oxidized lead-zinc ore and develop a scheme for its processing using a combined gravity-flotation technology for mineral raw material beneficiation. The mineralogical parameters of the ore, such as mineral composition, dissemination were investigated using microscopic examination of polished sections, chemical phase analysis, X-ray powder diffractometer (XRD) and JEOL JXA-8230 electron probe microanalyzer. The beneficiation of the ore by gravity and flotation beneficiation methods is studied and the jigging conditions, table concentrations, optimum grinding degree, reagent mode are determined and a set of technological studies is carried out. The Pb content of the gravity concentrate is 51.53%, and the Pb recovery is 46.91%. The Pb content of the flotation concentrate obtained from gravity concentration tailings reaches 50.69%, with a recovery of 24.53%. The average Pb content of the gravity-flotation concentrate is 51.24%, with a recovery of 71.44%. Therefore, the results provide important technical support for the processing of similar ores.

3D concrete printing is developing rapidly and is seen as an alternative to traditional construction methods. But today, the use of standard steel reinforcements and their integration into the concrete is very relevant for 3D concrete printing. The currently available measures provide the automated production of the reinforcement mesh but the concreting is manual, or automates both the creation of the reinforcement mesh and concreting but the integration of the reinforcement into the concrete is not sufficient to meet the requirements regarding strength and durability. To fill this gap, this study proposes a novel concept that automates the creation of reinforcement mesh and its integration into concrete during the 3D printing process. To verify the feasibility of the concept, tests were carried out: a mesh strength test according to DIN 488-4, an X-ray scanning test for the integration of the reinforcement mesh into concrete, and a cross-section cut test perpendicular to the printing direction and in line with the printing direction. The results show that the proposed concept is viable. © The Author(s) 2025. This article is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Additive manufacturing technologies for metals are developing rapidly. Among them, wire arc additive manufacturing (WAAM) has become widespread due to its accessibility. However, parts produced using WAAM require surface post-processing; therefore, hybrid technologies have emerged that combine additive and subtractive processes within a single compact manufacturing complex. Such systems make it possible to organize single-piece and small-batch production, including for the repair and restoration of equipment in remote areas. For this purpose, hybrid equipment must be lightweight, compact for transportation, provide sufficient workspace, and be capable of folding for transport. This paper proposes the concept of a multifunctional metal 3D printer based on hybrid technology, where WAAM is used for printing, and mechanical post-processing is applied to obtain finished parts. To ensure both rigidity and low mass, a 3-UPU parallel manipulator and a worktable with two rotational degrees of freedom are employed, enabling five-axis printing and machining. The printer housing is foldable for convenient transportation. The kinematics of the proposed 3D printer are investigated as an integrated system. Forward and inverse kinematics problems are solved, the velocities and accelerations of the moving platform center are calculated, singular configurations are analyzed, and the workspace of the printer is determined.

The study investigates the concentration of chemical elements in biological tissues (placenta and blood) of women from the Akmola region, Kazakhstan to assess the impact of environmental pollution on maternal and newborn health. The research conducted from 2018 to 2021 involved 67 placental and umbilical cord blood samples collected from women in four Akmola districts. The study utilized instrumental neutron activation analysis and electronic microscopy to determine the concentration of 28 chemical elements. Statistical methods were applied to analyze the distribution, including the mean values, standard deviations, and frequency distribution curves. Significant variability in chemical element concentrations was observed across samples, with notable differences in rare earth elements and heavy metals. Elements such as sodium (Na), calcium (Ca), and chromium (Cr) displayed high variation. The study identified a strong environmental influence on the accumulation of toxic elements in the placenta and blood. The accumulation of chemical elements in biological tissues was heterogeneous, influenced by natural and anthropogenic factors. Blood was found to be more sensitive to environmental contamination compared to the placenta, indicating the need for enhanced environmental health monitoring in the region.

Computer vision–based weed detection plays a critical role in agricultural robotics, enabling accurate, selective weeding. These systems operate on resource-constrained embedded platforms, which introduces a significant trade-off between accuracy and efficiency. This study presents a comparative evaluation of six detection models (YOLOv11n, YOLOv11s, SSDLite, NanoDet, Faster R-CNN, RT-DETR) for agro-robotic applications, measuring precision, recall, mAP@0.5, and runtime on low-power hard-ware. NanoDet achieved the highest detection accuracy (precision 98.6%, recall 94.2%, mAP@0.5 97.7%). YOLOv11s demonstrated similar performance (mAP@0.5: 96.1%) but required more computation. YOLOv11n provides the most favourable balance between accuracy and throughput (mAP@0.5: 94.6%, 207 FPS on a workstation). On Raspberry Pi 5, light models achieved 3–5 FPS. RT-DETR and Faster R-CNN exhibited high latency (3112–6500 ms/frame), which prevents real-time operation. NanoDet excelled in detection, while YOLOv11n provides the best balance between accuracy and efficiency for limited devices.

From technical vegetable oil  a by-product of sunflower oil production  a mixture of fatty carboxylic acids (FCA) was obtained via alkaline hydrolysis, acid treatment, and extraction. The composition of the extract was analyzed using IR and NMR spectroscopy, as well as mass spectrometry coupled with chromatographic analysis. It was shown that the extracted mixture contains nine types of fatty carboxylic acids. Nonionic surfactants  monoethanolamides (FCA-MEA) and diethanolamides (FCA-DEA) of the fatty carboxylic acids were synthesized by the esterification of acid mixture with monoethanolamine (MEA) and diethanolamine (DEA). The reaction yields were 92% and 95%, respectively. The chemical structures of the synthesized nonionic surfactants were confirmed by IR and NMR spectroscopy. The main adsorption characteristics of the resulting nonionic surfactants at the water/air interface were determined by measuring the surface tension of their aqueous solutions. It was found that FCA-DEA surfactant was more surface-active than FCA-MEA surfactant and the parameters of ПСМС and CMC/C20 for the first surfactant were higher than those for second surfactant. It was shown that the synthesized nonionic surfactants were effective foaming agents and stabilizers of oil-in-water (o/w) emulsions. Notably, the FCA-DEA-based surfactants formed relatively more stable foams and emulsions.

A method of correlation-interferometric direction finding has been improved, which effectively solves the problem of radio direction finding of radio emission sources under conditions of exposure to one or two masking interference. The problem was solved using the selection of an unmasked fragment of the spatial spectrum of the signal and the reconstruction of the missing samples of its signal group. As a result of the synthesis of the proposed method, estimates of signal samples were obtained as exact solutions to the proposed energy balance equations. The resulting solutions provide a significant increase in the signal-to-interference ratio and, accordingly, direction-finding accuracy without increasing the number of reception channels of the antenna array. As a result of the simulation, the dependences of the standard deviation of the bearing estimate on the signal-to-noise ratio in the presence of interference were built. Under the influence of one or two masking interferences and a signal-to-interference ratio of 0 dB, the use of the known direction-finding method without interference selection produces an anomalously large direction-finding error of more than 0.42 degrees, which is practically independent of the signal-to-noise ratio. The direction-finding method with selection of spectral signal samples masked by interference reduces the direction-finding error to 0.22 degrees when exposed to one interference and to 0.3 degrees when exposed to two interferences. This is due to the presence of power losses of the usable signal during the selection of its samples masked by interference. The proposed method of direction finding with reconstruction of signal samples provides a significant gain in accuracy by 3–30 times compared to the method of selection of masked samples in the range of changes in the signal-to-noise ratio (–20.5) dB. The direction-finding error of the proposed method decreases with increasing signal/noise according to a hyperbolic dependence. It is advisable to use the proposed direction-finding method when masking no more than two samples of the signal group © 2023, Authors. This is an open access article under the Creative Commons CC BY license