Brest State Technical University

The risk of accidental damage to buildings is currently increasing. This makes traditional design strategies, which focus on eliminating such impacts or designing key elements, ineffective and economically unreasonable. The most promising approach is to ensure the robustness of structures by limiting the extent of collapse after initial local failure. The goal of this study is to develop a calculation model for the resistance of a beam support section of a reinforced concrete frame under multi-level deformation in an accidental situation. The rationale for selecting a physical resistance model in the form of a structural node with support sections of beams and columns is explained. A calculation model has been developed to determine the resistance of support sections of beams in a reinforced concrete frame building under multi-level deformation in an extreme state resulting from an accidental situation. Analytical expressions have been obtained for the characteristic points of the "moment-rotation angle in a plastic hinge" diagram for flexural and compressive arch action, as well as for the "axial force-elongation" diagram for tensile catenary action. The proposed approach enables the evaluation of the load-bearing capacity of reinforced concrete frames under extreme conditions resulting from accidental events. The results of the study can be used to design structures that are more robust.

This study aimed to enhance rotational wood welding technology by developing a simplified prediction model for pull-out strength. The key findings can offer a robust evaluation framework to advance rotational wood welding and expand its applications in woodworking. For instance, (1) A comprehensive database of 689 previously published trials was curated to identify key factors: substrate diameter, effective welded length, and substrate density. (2) Comparative analysis of test outcomes and predictive models revealed consistent trends, suggesting that modeling techniques for self-tapping wood screws could be applied to rotational wood welding joints. (3) Univariate linear regression validated the primary factors, leading to a multivariate model for predicting withdrawal capacity. Theoretical predictions closely matched empirical data, highlighting the model’s industrial applicability.

The aim was to analyze the prognostic value of ventilation/ gas exchange dissociation markers to predict the treatment length in patients with the acute phase of COVID-19.Materials and methods: The analysis was performed using a database of 384 randomly selected patients from December 2021 to May 2022 with a confirmed diagnosis of the acute phase of COVID-19, aged 61±16 years. Spirometry of maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) was performed on 2,2±0,2 day of hospitalization with a portable MicroRPM device (CareFusion, UK) and measurement of surrogate oxygenation index (SpO2/FiO2), ROX index (SpO2/ FiO2)/respiratory rate) was carried out in all patients. Log-regression models were used (STATISTICA 10) to determine cutoff values for these functional variables and their ability to predict the patients length of hospital stay from the date of examination (≤ 7 vs > 7 days).Results: The lowest sensitivity (SE) and specificity (SP) were shown in models using only the respiratory muscle strength markers MIP (SE=54%, SP=70%) and MEP (SE=73%, SP=47%), that were the same in the combination of MIP and MEP (SE=65%, SP=58%). The areas under ROC were equal to 0.6 in all three models. The models based on hypoxia markers had a higher classification power (AUC 0,7) compared to the previous three, and the sensitivity value was higher in the model using the ROX index (SE = 58% and SP = 78%), but the specificity was better in the surrogate oxygenation index model (SE = 48% and SP = 88%). A complex model based on a combination of the two integral hypoxia indices, as well as a diaphragm strength marker (SpO2/FiO2+MIP*ROX+MIP) had the best sensitivity (67%) and specificity (84%), and the area under ROC reached 0.8.Conclusion: Indicators of respiratory muscle strength and oxygenation are suitable markers for combined models and algorithms for predicting hospital length of stay in COVID-19 patients.

A number of versions of a process flow diagram for the post-treatment of wastewater from the production of protective coatings and printed circuit boards are considered. It is shown that the choice of water treatment flow diagram depends mainly on the quality of the initial wastewater composition and on the requirements for the treated water. In this case, the simplest solution to the problem consists in separating the flows of the least polluted wastewater and in returning them after treatment to the lines of industrial water supply. As an alternative solution, joint reagent treatment of all the types of wastewater followed by post-treatment with the use of ion-exchange methods is proposed. However, staged wastewater treatment, wherein water is prepared in accordance with the technological requirements for the corresponding industries may represent a more flexible and cost-effective system.

Abstract. Climate change influences the water cycle and alters the spatiotemporal distribution of hydrological variables, thus complicating the projection of future streamflow and hydrological droughts. Although machine learning is increasingly employed for hydrological simulations, few studies have used it to project hydrological droughts, not to mention bivariate risks (referring to drought duration and severity) as well as their socioeconomic effects under climate change. We developed a cascade modeling chain to project future bivariate hydrological drought characteristics in 179 catchments over China, using five bias-corrected global climate model (GCM) outputs under three shared socioeconomic pathways (SSPs), five hydrological models, and a deep-learning model. We quantified the contribution of various meteorological variables to daily streamflow by using a random forest model, and then we employed terrestrial water storage anomalies and a standardized runoff index to evaluate recent changes in hydrological drought. Subsequently, we constructed a bivariate framework to jointly model drought duration and severity by using copula functions and the most likely realization method. Finally, we used this framework to project future risks of hydrological droughts as well as the associated exposure of gross domestic product (GDP) and population. Results showed that our hybrid hydrological–deep-learning model achieved > 0.8 Kling–Gupta efficiency in 161 out of the 179 catchments. By the late 21st century, bivariate drought risk is projected to double over 60 % of the catchments mainly located in southwestern China under SSP5-85, which shows the increase in drought duration and severity. Our hybrid model also projected substantial GDP and population exposure by increasing bivariate drought risks, suggesting an urgent need to design climate mitigation strategies for a sustainable development pathway.

The high labor intensity of constructing insulated brick walls has led to a significant reduction in brick consumption in the Republic of Belarus. Considering that in each region there is at least one brick factory equipped with modern technological equipment, and the reserves of mineral raw materials (sand, clay) for making bricks are practically inexhaustible, the development of an effective structural and technological solution for insulated brickwork is an urgent task. As practice shows, today the majority of brick buildings being erected are low–rise (3-5 floors) – these are secondary schools, kindergartens, clinics, buildings for household purposes (laundries, dry cleaners, etc.), as well as administrative buildings. The floor layout of the premises of these buildings is, as a rule, cabinet (the number of window openings is significant). In this regard, it is proposed to use factory-made insulated brick panels (piers) to reduce the labor intensity of constructing the facades of such buildings. A distinctive feature of the proposed solution for insulated brickwork from those commonly used is that, to increase operational efficiency, it is made of two separate structural elements: load-bearing and heat-insulating and decorative. The paper describes in detail the organization and technology of work on the production of the main structural elements of brick insulated facade panels (piers) in factory conditions. The proposed design solution for the facade of brick buildings with a cabinet layout allows the manual technological process of constructing such buildings to be converted into a mechanized one – installation of factory-made insulated brick panels (piers), which will significantly reduce the labor intensity of constructing insulated brick walls. The division of buildings under construction into tiers, the height of which is linked to the range of technological operations and the building materials used, makes it possible to exclude from the work the use of lifting equipment (scaffolding), as well as the delivery of pallets with bricks and mortar boxes to the bricklayer's workplace.

Using the method of applying instantaneous point sources, a solution was obtained to the problem of heat conduction during surface heating of a body in the form of a half-space by a uniformly distributed highly concentrated heat flux moving at a constant speed along a rectilinear trajectory with a different shape of the heating spot at constant thermophysical characteristics of the material. The effect of temperature loading modes and the shape of the heating spot on thermal processes in the heat-affected zone is studied. The surfaces and lines of the temperature level are constructed for different moments of time and speed loading modes in different planes of the heating zone. Time dependences of temperatures, heating and cooling rates for body points are given. The shortcomings of the methods used for linear thermal conductivity, the lack of direct consideration in the design scheme of the surface melt zone of the material do not allow one to reliably assess the effect of heat treatment modes on changes in material properties, focusing only on the level of the maximum design temperature. In this regard, the structure formation of metal in the zone of thermal action is proposed to be associated with a thermal impulse, i.e. the total thermal energy perceived by the material at a given point of the body, as well as with the effective structurization impulse introduced into consideration, which characterizes the energy spent on the process of structural transformations of the material, and the structurization time at a point and some volume of the body. The dependencies of these values on the speed of movement and the shape of the heating spot are presented. The considered approaches can be applied to various metals and alloys. The research results can be used to develop more effective methods for determining the optimal modes of surface hardening of metal products with a high-energy source.

Shrews and small rodents inhabit the drainage channel banks in reclai med areas and have their own helminth complex. The aim of the study is to conduct the 3rd research period during 2015-2019 the helminth fauna of these animals living on the drainage channel banks of model reclamation systems in Brest Polesie (south-western part of Belarus), to establish the species composition of helminths and the animal infection by these, and to compare the data obtained with previous research periods. 4,000 trap-days were worked out. 151 specimens of shrews of 4 species and 510 small rodents of 8 species were caught. Animals were examined by the method of complete helminthological dissections. Their numbers were 3.78 and 12.75 individuals per 100 trap-days, and helminth infection was 94.7% and 65.9%, respectively. 66 helminth species were found in animals. The dominant helminth species in infection have been identified. The trematode Prosolecithus danubica Tkach et Bray, 1995 (definitive host: common shrew), the acanthocephalans Centhrorhynchus aluconis (Müller, 1780) (larval host: lesser shrew) and Moniliformis moniliformis (Bremser, 1811) (definitive host: striped field mouse) are new species of helminths for Belarus. New hosts in Belarus have been found for 6 helminth species. Shrews and small rodents are involved in the life cycles of bird, non-ruminant artiodactyl and carnivorous mammal helminths. Nine helminth species have significance for medicine and 7 species for veterinary science. The results are compared with data from the 1st (1996-1999) and 2nd (2005-2010) research periods.