The article analyzes the extent of soil contamination caused by military activity and justifies approaches to its remediation. The relevance of the study is in the need for a comprehensive examination of the dynamics of changes in the ecological state of the territory subjected to technogenic load and the search for technological solutions for its restoration. The most dangerous phenomenon is the accumulation of heavy metals, which suppresses soil biological activity and worsens its agronomic properties. However, existing methods of soil remediation are ineffective in complex and heterogeneous contamination. The research conducted a comparative assessment of the concentrations of lead, cadmium, and mercury in the contaminated territory of Kalchenkivska village council (Sumy region, Ukraine) using data from 2021 and 2026. A significant increase in lead concentration, from 1.15–2.75 mg/kg in 2021 to 10.8–84.7 mg/kg in 2026, was observed. For cadmium, an increase in content from 0.05–0.09 mg/kg in 2021 to 0.22–1.36 mg/kg in 2026 was also recorded. Mercury in 2021 was below the analytical method’s detection limit, while in 2026 it was detected in various samples, with a maximum value of 0.092 mg/kg. Based on the spatial distribution patterns of heavy metals obtained, the need for remediation measures in the studied area was substantiated. Digestate and sunflower husk bioash were identified as promising components for organo-mineral remediation systems due to their complementary fertilizing and immobilization properties. Three prospective pelletized formulations containing 10 %, 20 %, and 30 % wt. bioash were proposed for further evaluation of their remediation potential.
The article aims to improve the quality of dried blueberries for use as an encapsulating agent. The effects of different blueberry pretreatment methods on drying parameters were investigated, and combined drying regimes were developed for blueberries subjected to various pretreatments, thereby reducing drying time by approximately 23 % compared with existing methods. The dependence of the specific latent heat of moisture evaporation from whole and pretreated blueberry tissues on relative moisture content was established at drying temperatures of 60 °C and 80 °C. The specific heat capacity of blueberries was found to depend primarily on their moisture content, a characteristic of moist, capillary-porous materials. At low moisture contents, however, anomalies were observed as a pronounced increase in effective heat capacity at temperatures of 55–60 °C. Infrared (IR) pretreatment was shown to accelerate the breakdown of the wax coating during subsequent drying. The resulting dried blueberries were used as an encapsulating agent to form an RS3-based carrier matrix. The dispersion and rheological properties of the carrier matrix containing blueberry biologically active compounds were found to depend significantly on the berry pretreatment method. The blueberry flavonoid complex reduced the viscosity of resistant starch, with the lowest viscosity observed for the RS3-based carrier matrix containing biologically active compounds from blueberries dried in a convective dryer. Gel-forming ability was also evaluated, demonstrating that resistant starch forms a stronger gel than native starch and that incorporating blueberries significantly enhances gel strength. Based on these findings, a food system model was proposed in which the resistant starch content and the blueberry flavonoid complex are the main factors influencing the rheological properties of the resistant starch-based carrier matrix.
The process of preparing construction mixtures in an electrically driven rotary mixer was investigated in this research. It was found that during the technological stage of adding water to the dry components, the mixing process is accompanied by a sharp increase in required mixing power that persists for up to 10 s and reaches approximately 1.5 times the normal level. As a result, mixers were equipped with motors of excessive power. The article aims to improve the energy efficiency of rotary mixers during operation. An analysis of technical solutions showed that mixer rotors with adjustable blade attack angles can be used to smooth out load peaks. Rotating the blades while the mixer was operating reduced their frontal drag area. To evaluate the quantitative impact of blade angle of attack on the power required for mixing, a theoretical model was developed, and analytical expressions describing this effect were derived. To assess the energy efficiency of rotary mixers, methods were developed to determine their energy consumption over the full operating cycle of preparing a construction mixture. It was established that the use of a blade angle control mechanism reduces peak loads by more than 50 %, enabling the use of a motor with half the rated power and improving motor efficiency by increasing the average load level by approximately 25 %, thereby bringing it closer to the optimal operating range. The results of this research enable improvements in the energy efficiency of existing rotary mixers.
The production of wood chips for the pulp-and-paper, wood-based panel, and bioenergy industries requires maintaining a stable granulometric composition (particle-size distribution) of the product. A promising approach to improving chip quality is optimizing screening systems in drum wood chippers. This study aims to develop a mathematical model of the interaction between wood chips and the screen and to substantiate its rational design parameters. The study used methods of solid-body motion mechanics, mathematical modeling, and experimental testing. A mathematical model of the impact interaction between wood chip particles and the screen was developed, accounting for the kinematic parameters of particle motion and the material’s physical and mechanical properties. A relationship for determining the number of sections of a stepped screen was derived, and the patterns governing particle movement within the inter-drum space were established. The influence of the number of screen sections and the radial distance between the screen and the drum on the efficiency of wood chip sizing was experimentally investigated. It was found that using a sectional screen improves the separation of substandard particles and the fractional composition of the output product. The following rational parameters were obtained: 11 screen sections and a radial spacing of 15 mm. Under these conditions, the proportion of the substandard fraction is 8–15 %, whereas for a plate-type screen it is 25–32 %. The results may be used in the design and modernization of drum wood chippers.
Sawdust, originally a waste product from sawmills, can be effectively used as a cooling, energy-saving method by reducing room temperature when applied as a roof coating with added epoxy. This method helps coat the surface of Galvalume roofs exposed to direct sunlight. This study investigates the effect of a wood powder-epoxy composite coating on reducing the temperature beneath Galvalume roofs. Data were collected using a miniature box measuring 0.125 m3, designed to resemble a room with ventilation and a roof made from wood-powder composite, compared to a Galvalume roof with no coating or only an epoxy coating. Four thermocouples were placed on the miniature box. The four temperature sensors can measure air temperatures above and below the roof, as well as the room temperature. Testing was conducted using six miniature boxes, each measuring simultaneously. This allowed for analysis of the optimal use of composite coatings on galvalum roofs. The results showed that adding various types of wood powder could reduce the room temperature by up to 3.3 °C. Therefore, adding a layer of wood powder epoxy composite to the Galvalume roof can reduce the roof’s thermal conductivity, lower the temperatures inside and outside the room, and reduce the energy required to cool the mini box room by 464.1 J.
