Vinnytsia National Technical University

The consistent detection of low-level carbon monoxide (CO) and methane (CH 4 ) is important for safety, environmental monitoring, and early leak identification. Semiconductor metal oxides are considered to be the most promising candidates for such applications. However, their performance is usually hindered by limited speed and less sensitivity. Herein, three heterojunction systems—ZnO/SnO 2 (Z/S) (n–n), NiO/ZnO (N/Z) (p–n), and SnO 2 /NiO (S/N) (p–n)—were synthesized through a controlled hydrothermal route. A systematic comparative study of these n–n and p–n interfaces is carried out to determine the most effective heterojunction structure for improved room-temperature CO and CH 4 sensing performance. Structural and morphological studies have proved a well-defined interface with homogenous surface features. In fact, the phase purity was well proved by X-ray diffraction, the homogeneous element distribution was identified by field emission scanning microscopy/energy dispersive X-ray spectroscopy, and the surface roughness was decreased, as determined by atomic force microscopy 2D/3D profiles with R a values of 81.547 nm (Z/S), 46.084 nm (N/Z), and 24.272 nm (S/N). Ultraviolet–visible spectroscopy confirmed the sequential bandgap narrowing: 3.2 eV for Z/S, 2.6 eV for N/Z, and 2.4 eV for S/N, indicative of enhanced electron interaction across the interfaces. J–V measurements exhibited diode-like behavior, showing a sequential decrease in cutoff voltage to 0.7, 0.6, and 0.4 V, respectively. Accordingly, electrochemical impedance spectroscopy analysis showed a decrease in charge-transfer resistance from 16.2 to 2.2 and 1.4 kΩ. Improved electron mobility has also been demonstrated from thickness measurements, which revealed that the S/N film exhibited the thinnest layer (0.4 μm) relative to Z/S (2.0 μm) and N/Z films (1.4 μm). This was further emphasized in the gas-sensing experiment, which demonstrated the clear omnipotence of the S/N heterostructure; hence, it enabled a fast response/recovery time of 15/24 s for CO and 18/42 s for CH 4 at low concentrations with high sensitivity and long-term stability in ambient conditions. The improved sensing ability could be ascribed to the strong p–n junction, smallest depletion width, and low interfacial resistance. Moreover, the sensing ability of the sensor was validated using machine learning algorithms, wherein consistently, the Random Forest (RF) algorithm appeared to have a stronger predictive power than Support Vector Machine (SVM). In fact, RF performed better than SVM by achieving higher R-Squared (R 2 ) values for each regression problem, which were generally in the range of 0.80–0.85 compared to the lower and more fluctuating performance of SVM. Likewise, a drift was noticed in the classification performance where RF achieved accuracies of 0.91/0.88 for CO and 0.93/0.89 for CH 4 under A1 and A2 scenarios, respectively, outperforming SVM in all cases. Finally, this study hereby confirms that the concept of heterojunction, specifically the S/N interface, combined with machine learning-assisted analysis, provides a promising route forward for the realization of next-generation room temperature gas sensors with high sensitivity, fast response, and accurate predictive capabilities.

Precise pressure regulation in nonlinear shell-and-tube steam condensers is essential for maintaining thermal efficiency and operational safety in power generation plants; however, conventional proportional-integral (PI) and proportional-integral-derivative (PID) controllers struggle with nonlinear dynamics, leading to overshoot, slower settling, and reduced robustness. In this regard, a novel hyperbolic tangent-based PID (tanh-PID) controller is developed in this study to introduce smooth nonlinear gain modulation, enabling enhanced damping behavior and improved transient shaping. The recently introduced artificial lemming algorithm (ALA) is employed to optimally tune the proposed controller for integral of time-weighted absolute error minimization. Extensive simulation studies are performed using a comprehensive nonlinear condenser model incorporating steam–air interactions and hot-well dynamics. The proposed strategy is benchmarked against four competitive optimization algorithms (coati optimization algorithm, dandelion optimizer, success-history based adaptive differential evolution with linear population size reduction, and adaptive artificial electric field algorithm) and compared with state-of-the-art PI and fractional-order PID (FOPID) controllers reported in the literature. The ALA-tuned tanh-PID achieves the lowest integral of time-weighted absolute error (2.1189), fastest rise time (0.5960 s), minimal settling time (12.4799 s) and overshoot (5.8056

The object of research is the process of designing and optimizing parking areas in complex geometric configurations in conditions of dense development. The main problem is to solve the use of areas of complex geometric configuration for parking areas. In addition, there are currently no universal models and methods for the corresponding calculation and optimization. The result of the work was the receipt of a universal mathematical model with which it is possible to determine the number of parking spaces based on the geometric dimensions and area of the plot. A special feature is the possibility of calculating for complex geometric configurations (polygons). For this, the Gauss formula and the JavaScript programming language are used. The initial data are geodetic measurements, and the error in such a calculation is less than 2%. The development of JavaScript code based on the shoelace formula was practical importance. The experimental object was the residential area “Vyshenka” in Vinnytsia (Ukraine). The selected plot has an area of 1350 m2 with an initial number of parking spaces before optimization –50, after –59. In general, the efficiency of using the area increased from 70% to 88%. In addition, a 22% reduction in accidents is noted, which indicates the significant effectiveness of the model and minimal calculation error. A feature of the proposed solution is also that not only linear dimensions are taken into account, but also the relief, infrastructure facilities and the initial shape of the site. There is also the possibility of integration into web applications and CAD programs for simultaneous planning and construction, which allows for an increase in the number of parking spaces of up to 20% without expanding the territories. The results of the modeling can be used by engineers and builders to improve the landscaping of residential areas where there is no possibility for expanding the territories, programmers – by integrating the model into web applications and business.

This article examines the process of wood pyrolysis as an effective method for converting biomass into renewable energy sources with high energy potential. Pyrolysis, which involves the thermal decomposition of organic raw materials in the absence of or with limited access to oxygen, in the construction and industrial sectors, pyrolysis helps improve energy efficiency, reduce waste, and promote the development of alternative energy sources, produces three main products: bio-oil (liquid fuel), biochar (carbon residue), and synthesis gas (a mixture of hydrogen, carbon monoxide, and methane). Each of these products has specific properties, advantages, and applications. Bio-oil can be used as an alternative to diesel fuel in power plants, biochar as a soil conditioner, fertilizer, sorbent, or activated carbon, and synthesis gas as fuel for electricity generation or as a feedstock for the chemical industry, particularly for the synthesis of methanol, ammonia, and hydrogen. This paper presents the basic equations and relationships for estimating the energy potential of biomass, taking into account its moisture content, density, calorific value, and elemental composition. It also examines approaches to determining the yield of pyrolysis products depending on the process temperature, heating rate, treatment duration, and type of wood. Particular attention is paid to the analysis of the average heat of combustion of the resulting products, which allows for an assessment of their energy efficiency and the feasibility of their use under various conditions. It is shown that the use of pyrolysis contributes to a significant reduction in CO₂ emissions compared to direct wood combustion or the use of fossil fuels. Particular emphasis is placed on the environmental benefits of the technology and the possibilities for its integration into modern agricultural systems. Biochar produced through pyrolysis serves as a stable source of carbon in the soil, improving its structure, water-holding capacity, microbial activity, and overall fertility. The results confirm the feasibility of widespread implementation of wood pyrolysis technologies as an element of the circular economy, aimed at reducing anthropogenic impact on the environment, developing environmentally safe energy, and promoting the rational use of natural resources.