Prydniprovska State Academy of Civil Engineering and Architecture

Real-time evaluation of an electric bus's stability, focusing on four key stability factors: lateral stability, longitudinal stability, dynamic stability, and static stability. Electric buses offer distinct advantages over large-class buses due to their lower center of gravity, primarily attributed to the placement of heavy batteries. This feature significantly improves stability, particularly during cornering and abrupt maneuvers. However, real-time monitoring of these stability parameters is essential to prevent potential rollovers, ensuring operational safety in varying driving conditions. In this study, we compare the stability characteristics of electric buses with large-class and small-class buses, analyzing how the lower center of mass in electric buses contributes to superior handling. The research highlights that despite the inherent stability benefits, active control mechanisms are crucial for maintaining safety, especially under dynamic conditions. The paper presents methods for real-time stability assessment and proposes an online monitoring framework that allows continuous evaluation of these characteristics to optimize safety and performance. The findings emphasize the importance of real-time stability control in electric buses, offering a comparative analysis of the mentioned stability factors between electric buses, large-class buses, and small-class buses, and suggesting the integration of online monitoring systems to prevent instability and improve overall vehicle safety.

Abstract. Рurpose. The aim of the work is to study the shrinkage of keralite concrete on carbonate sand including under the influence of composition factors. Methodology. The study of shrinkage and creep of keralite concrete on carbonate sand was carried out according to the method of experiment planning. The factors taken as factors are: 1.Cement consumption C, kg/m3 – Х1. 2.Aggregate-structural factor r – Х2. 3.Age of concrete by the moment of loading t0, days.- Х3. Shrinkage strains were determined according to the requirements of [10]. Results. Our experiments and experiments [4; 9; 13; 14; 17] confirmed the known rule about the independence of the effect of cement consumption within the usual norms for obtaining mixtures of the same mobility. Consequently, an increase in cement consumption at constant water consumption leads to an increase in the strength and relative volume of crystalline aggregate, which, like inert aggregate, has a restraining effect on the volumetric changes in the gel accompanied by concrete shrinkage. Water is the cause of moisture-physical phenomena in cement stone causing its shrinkage. Therefore, for the most complete reflection of the influence of composition factors, it is necessary to introduce water consumption into the structure of the dependence. Scientific novelty. The consistent application of dispersion, correlation and regression analyses of the results of experimental studies allowed to establish the structure of dependence between εsc(∞, tw) and the composition factors W, C, r, to determine the coefficients at the regression terms and the necessary static characteristics. Practical significance. Prediction of shrinkage strain limits εsc(∞, tw) is important for their normalisation and further design of concrete compositions. However, the practical use of the regression equation for predicting εsc(∞, tw) is difficult because it only indirectly takes into account the influence of such a factor as the amount of mixing water.

When processing natural and artificial building materials, it is important to obtain precise cuts and perfect edges (especially when processing ceramic products). A diamond-cutting disc on a metal base can do this job. During high-speed cutting and grinding, a large amount of heat is generated, and the disc heats up to 650 °C and higher. At such temperatures, graphitization of diamond grains occurs, and, as a natural result, cutting stops. In addition, the diamond blade becomes deformed, causing it to jam in the workpiece. Cooling of the cutting disc can be partially accomplished by blowing a boundary layer of air. However, this is ineffective in significantly reducing the wheel’s temperature and increasing the time of continuous operation of the cutting disc. Reducing the temperature of the cutting disc is possible by replacing the air boundary layer with another type of cooling medium. The possibility of replacing the air boundary layer with another type of cooling medium using a Ranque-Hilsch tube was investigated. This allows you to extend operating time by 15

This study focused on the development and verification of the effectiveness of a new energy-efficient composite wall made of polystyrene foam concrete in a fixed formwork, prepared using light steel thin-walled structures and polystyrene foam concrete as an aggregate. This research included the development of the new patented solution, a multi-criteria analysis of this solution through comparison with the most common solutions, and experimental investigations of the heat transfer resistance of the new wall. Based on the results of a multi-criteria analysis involving eight criteria, it was established that the new solution of a composite wall in a fixed formwork is more effective than 13 traditional alternatives. Experimental studies on the heat transfer resistance, conducted at the laboratory of the Scientific Research Institute of Building Structures in Kyiv, demonstrated the heat-insulating properties of the new wall. The installation of the new wall at an actual construction site confirmed the reduction in labour and material consumption owing to the new technology. Thus, for the first time, the experimental results of the heat transfer resistance of the new wall at two cross sections (maximum thickness of polystyrene foam concrete and maximum accumulation of steel elements) made it possible to substantiate the need for external insulation of the wall. Low values of the specific labour intensity, material intensity, as well as the possibility of installing wall elements with minimal use of construction equipment make it possible to use the developed solution for a wide range of construction structures.

The paper is devoted to the study of properties of pseudo-Riemannian spaces admitting nontrivial geodesic mappings. Necessary and sufficient conditions are found for A-threesymmetric spaces to admit nontrivial geodesic mappings. The research is carried out locally, in tensor form without restrictions to the sign of the metric tensor and the signature of the space.