National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”

This study investigated an oxidative treatment method for apricot kernel shells (AKS) to extract their polysaccharide component for subsequent conversion into liquid biofuel. The aim was to overcome the inherent recalcitrance of lignocellulosic biomass by selectively removing lignin and enriching cellulose content - critical steps for efficient enzymatic hydrolysis. The AKS were treated in an acetic acid medium with hydrogen peroxide under varied conditions, and the resulting substrates were analyzed for yield, cellulose, and lignin content. Mathematical modeling, using regression equations with statistically significant coefficients, accurately described the changes in substrate properties depending on the treatment parameters. Optimization of this multi-criteria process using a generalized Harrington desirability function identified 9% hydrogen peroxide and 120 minutes of treatment as optimal parameters, yielding a composite desirability value of 0.7966. Under these conditions, the obtained substrate exhibited a 50.1% recovery, 54.4% cellulose, and 12.4% lignin, closely matching theoretical predictions. Visual and IR spectroscopic analyses confirmed the efficiency of the treatment: the processed substrate (AKS-S) displayed a lighter color, indicating reduced lignin and increased cellulose content compared to raw AKS. IR spectra further revealed significant lignin removal and degradation of low-molecular-weight hemicelluloses, which is advantageous as it minimizes the formation of inhibitory byproducts during enzymatic hydrolysis. The treatment also doubled the specific surface area and increased porosity six-fold, improving enzyme accessibility. These findings underscore the potential of this oxidative treatment as an effective pretreatment strategy for converting agricultural waste into a high-quality substrate for biofuel production.

Plant viruses can cause substantial yield losses, yet disease severity often varies between seasons because plants frequently experience heat or cold episodes before infection. In this study, we tested whether such temperature conditions affect the plant’s redox balance and alter its response to Tomato bushy stunt virus (TBSV) infection in Nicotiana benthamiana. Plants were exposed to short-term heat and cold stress, after which they recovered before virus inoculation. Following this, we assessed the reactive oxygen species (ROS) content, lipid peroxidation (LPO), oxidative DNA damage, stress-related proteins, redox-associated enzymes, and antioxidant metabolites. TBSV led to non-parallel ROS responses during infection, with consistently elevated hydrogen peroxide in infected plants but reduced superoxide relative to corresponding mock controls. Heat pre-exposure caused pronounced LPO that decreased further after infection, whereas cold pre-exposure stabilized malondialdehyde near levels observed at 25 °C. Both thermal stress and infection increased 8-oxo-dG and were associated with distinct changes in 8-oxoguanine glycosylase abundance. Infection strongly induced heat shock protein 90 (and moderately heat shock protein 70), while prior heat limited further chaperone induction by TBSV. These results indicate that viral infection develops within and is limited by the host’s oxidative state, where redox homeostasis may restrict infection-related processes, and infection leads to changes in this redox environment that are favorable for its development.

Abstract In ferromagnetic cores, the magnetic field inside a toroid is spatially non-uniform, and the relative magnetic permeability μ(H) depends nonlinearly on the magnetic field strength H . In electromagnetism courses, when determining mutual inductance, it is usually assumed that the relative magnetic permeability of the core material is constant, which significantly affects the calculated values of mutual inductance. In the proposed method for determining mutual inductance, a graphical analysis of the function μ(H)/H is used to account for the non-uniform distribution of the magnetic field and magnetization in a toroidal core. When determining the magnetic flux through the cross-section of the core, integration with respect to the magnetic field strength is employed. Since an analytical expression for the relative magnetic permeability μ ( H ) is not available and is given graphically, the required integrals are evaluated graphically. The method is illustrated by calculation examples for a toroidal core made of American Rolling Mill Company iron. The results show that the mutual inductance depends on the current in the primary coil, the number of turns, and the ratio of the outer to inner radii of the core. A comparison with the method based on a constant relative magnetic permeability demonstrates that such an approach can lead to significant errors, especially in regimes where the magnetic field varies considerably across the core cross-section. The proposed method accounts for the nonlinearity of the magnetic properties of the ferromagnetic core and the non-uniformity of the magnetic field. It helps students relate theoretical concepts to the experimental properties of materials. The use of digital tools for determining the areas under the curves of plotted functions helps simplify certain calculations and improve the accuracy of the obtained results.

Acid activation of bentonite clay is an effective approach for producing porous sorbents and acid catalysts. In this study, the influence of acid treatment on the structure and sorption properties of montmorillonite (MMT) was examined. Natural MMT was treated with hydrochloric and nitric acids of different concentrations under various thermal conditions. The samples were characterized by XRD, SEM, EPMA, low-temperature N₂ adsorption–desorption, and potentiometric titration. Acid activation resulted in the replacement of interlayer cations with protons and partial leaching of Mg²⁺, Fe³⁺, and Al³⁺ from the lattice, leading to an increase in specific surface area from 89 m²/g to 287 m²/g. The uranium sorption capacity increased from 56 µmol/g to 127 µmol/g due to the formation of new sites for sorption. In contrast, strontium and cesium sorption decreased, except for nitric acid treatment, which enhanced Cs⁺ uptake to 310 µmol/g. The Langmuir model provided the best fit to the sorption data, indicating a predominant monolayer chemisorption mechanism. The type and strength of acid determine the structural stability and selectivity of the sorbent. Mild activation, especially with nitric acid, preserves the clay framework and improves its suitability for uranium removal and further modification in environmental remediation applications.

We investigated how a magnetic topological defect affects the vacuum polarization of a charged massive scalar field in a flat (3+1)-dimensional space-time. The defect was modeled as an impenetrable-to-matter-field, finite-thickness tube with magnetic flux inside. We implemented the most general form of the Robin boundary condition on the surface of the magnetic tube, which enables a fully general analysis of the problem. We found that in flat space-time, the total vacuum energy generated by a magnetic topological defect depends on the curvature (ξ), except for special cases corresponding to the Dirichlet and Neumann boundary conditions. By contrast, when Robin’s general boundary conditions are imposed, the induced vacuum energy acquires an explicit dependence on the curvature coupling (ξ), which is significant even in flat space-time. A detailed study of the dependence of the effect on the boundary-condition parameter was carried out. The obtained results highlight the nontrivial role played by boundary conditions in vacuum polarization phenomena.

The Chinese restaurant process is a basic sequential construction of consistent random partitions. We consider random point measures describing the composition of small blocks in such partitions and show that their scaling limit is given by the projective limit of certain inhomogeneous Poisson measures on cones of increasing dimension. This result makes it possible to derive classical and functional limit theorems in the Skorokhod topology for various characteristics of the Chinese restaurant process.

Two Ni–Zn spinel ferrites samples with different iron contents were investigated by quantitative X-ray diffractometry and magnetization measurements. The Fe-deficient sample was found to hold 34.4 wt% of halite phase Ni0.7Zn0.3O in addition to primary spinel ferrite phase with Ni0.6Zn0.4Fe2O4 composition, while the near-stoichiometric Ni0.7Zn0.3Fe2O4 sample contained only 5 wt% of Ni0.7Zn0.3O halite. Magnetization study indicated preferentially ferrimagnetic ordering in both samples. The coefficient of magnetocrystalline anisotropy K1 was calculated from the magnetization data using the law of approach to saturation. The results revealed significant increase of K1 in Fe-deficient sample that can be employed in microwave absorption applications.

The article is dedicated to the study of the principles, structure, and mechanisms of managing advertising campaigns in the video production market, which operates at the intersection of creative, technological, and communication-management processes. In the current conditions of digital transformation and the rapid growth of visual content consumption, video production is becoming not only a technical process of creating audiovisual materials but also a strategic tool for shaping brand perception, emotional engagement, and long-term competitive advantages for companies. This underscores the need to shift from traditional advertising approaches to integrated management systems that combine analytical research, creative design, and technological innovation. The article examines the theoretical foundations of video production as both a service and a product, highlighting its dual role in shaping communicative and reputational value. It is shown that the effectiveness of an advertising campaign in this sector depends on the coherence of concept development, creative dramaturgy, production and post-production stages, as well as the alignment of these elements with strategic marketing objectives. The main models of interaction between the client, the production company, and the media agency are analyzed, defining the distribution of responsibilities, decision-making logic, and risk sharing. The article emphasizes the importance of integrating creative identity, technological capabilities, and strategic planning to achieve maximum communication effectiveness. It substantiates the approach where video content serves not only as a carrier of information but also as a demonstration of the company's professional style and expertise. Special attention is given to the determinants influencing the choice of communication tools - market, sociocultural, technological, behavioral, creative, and innovative - which shape the adaptability and competitiveness of advertising campaigns in the video production market.

Autonomous navigation in cluttered and dynamic industrial environments remains a major challenge for mobile robots. Traditional occupancy-grid and geometric planning approaches often struggle in such unstructured settings due to partial observability, sensor noise, and the frequent presence of moving agents (machinery, vehicles, humans). These limitations seriously undermine long-term reliability and safety compliance—both essential for Industry 4.0 applications. This paper introduces S3PM, a lightweight entropy-regularized framework for simultaneous mapping and path planning that operates directly on dense 3D point clouds. Its key innovation is a dynamics-aware entropy field that fuses per-voxel occupancy probabilities with motion cues derived from residual optical flow. Each voxel is assigned a risk-weighted entropy score that accounts for both geometric uncertainty and predicted object dynamics. This representation enables (i) robust differentiation between reliable free space and ambiguous/hazardous regions, (ii) proactive collision avoidance, and (iii) real-time trajectory replanning. The resulting multi-objective cost function effectively balances path length, smoothness, safety margins, and expected information gain, while maintaining high computational efficiency through voxel hashing and incremental distance transforms. Extensive experiments in both real-world and simulated settings, conducted on a Raspberry Pi 5 (with and without the Hailo-8 NPU), show that S3PM achieves 18–27% higher IoU in static/dynamic segmentation, 0.94–0.97 AUC in motion detection, and 30–45% fewer collisions compared to OctoMap + RRT* and standard probabilistic baselines. The full pipeline runs at 12–15 Hz on the bare Pi 5 and 25–30 Hz with NPU acceleration, making S3PM highly suitable for deployment on resource-constrained embedded platforms.