A numerical study of heat transfer and hydrodynamics in plate heat exchangers with corrugated fins was carried out. The effect of corrugation pitch on heat flow and pressure drop was studied. The study was carried out using computational fluid dynamics in the ANSYS software package (v. 19.2). The results of the study showed that increasing the corrugation pitch from n = 5 to n = 9 leads to an increase in heat flow of 10.83% and a pressure drop of 28.30%.

Keywords: plate-fin heat exchanger, corrugated fins, heat transfer, hydrodynamics, numerical study, calculation, heat flow, pressure drop, energy efficiency, cooling system

Using numerical modeling, a study of heat transfer and hydrodynamics in plate heat exchangers with corrugated fins was carried out, while the height of the corrugation profile varied from 2 to 4 mm. The influence of profile height on heat flow and pressure drop was studied. It was revealed that an increase in the profile height leads to an increase in heat flow up to 34.05% and pressure drop up to 54.54%.

Keywords: corrugated heat exchanger, cooling system, microelectronics, profile height, heat flow, pressure drop, heat transfer, hydrodynamics, calculation, numerical modeling

The overview of the existing horizontal and vertical nodal joints for 3D modular building blocks and plane elements has shown that tongue and groove is the most commonly used connection today. Other types of module attachments are also discussed. Special attention is paid to a modular integrating system encompassing a design description. It is emphasized that the efficiency of modular construction depends, among others, on nodal joints used therein.

Keywords: modular construction systems, operational reliability, horizontal and vertical attachments, coupling bolts, tongue and groove connection

The functional and spatial aspects of the formation of the architectural environment of medical rehabilitation and rehabilitation centers for injured athletes are investigated. The theoretical basis on the problems of functioning of similar facilities - rehabilitation centers for the disabled is considered, the characteristic components of the environment are identified, as well as the technological stages of the rehabilitation process. The generalization of the best Russian experience and existing architectural and planning solutions of medical institutions with rehabilitation functions is carried out. A comparative analysis of analog facilities was carried out in three conditional groups: a) large medical centers with rehabilitation functions for the disabled; b) multidisciplinary rehabilitation centers; c) specialized rehabilitation centers for athletes. A number of promising approaches and trends are identified that can be applied to the formation of conceptual models and adaptive architectural and environmental solutions for sports medicine and rehabilitation centers.

Keywords: rehabilitation center for athletes, functional-spatial, architectural-planning, environmental solutions, models, approaches

The cases of uneven compression of a concrete cylinder in the case of simple loading and comprehensive uneven compression of a spiral-reinforced concrete cylinder under disproportionate loading are considered. The dependences of longitudinal, transverse and volumetric deformations on longitudinal stress are obtained.

Keywords: longitudinal stress, circumferential stress, longitudinal deformation, circumferential deformation, spiral reinforced concrete strut, shear strain intensity, shear stress intensity

Currently, there is an increase in the number of scientific papers on models, methods and software and hardware for image processing and analysis. This is due to the widespread introduction of computer vision technologies into information processing and control systems. At the same time, approaches that provide fast image processing in real time using limited computing resources are relevant. Such approaches are usually based on low-level image filtering algorithms. One of the tasks to be solved in computer vision-based systems is the localization of round objects. These objects have the property of radial symmetry. Therefore, the approach based on the Fast Radial Symmetry Transform, which is considered in this paper, is effective for solving this problem. The paper describes the basic steps of the basic transformation, provides a procedure for determining the centers of radially symmetric areas for localization of round objects in images, and discusses examples of its application.

Keywords: computer vision, image processing, image analysis, localization of objects, methods of localization of round objects, fast radial symmetry transf, detecion of the centers of radially symmetric areas

The focus is on the building construction technologies using 3D modular building blocks, which are capable of changing their geometric dimensions and shape or remaining unchanged during installation. The paper discusses the main advantages of using 3D modular building blocks for building construction and offers specific examples showing the related process flows. It also shows horizontal and vertical nodal joints and provides a comparison of two options based on certain criteria of installation adaptability.

Keywords: buildings, construction technology, installation and transport manufacturability, horizontal and vertical connections, technological processes

The presented article analyzes the urban development of the cities of the Leningrad region of Luga, Kingisepp and Tikhvin, which have the potential to be included in the list of historical cities of regional significance, to identify the features of their urban development through various historical eras, as well as the existing problems of the urban environment.

Keywords: historical settlements, urban planning reform of Catherine II, Leningrad region, urban planning formation of cities

A numerical simulation was used to investigate heat transfer in plate-fin radiators with round fillet profiles of various depths, including 0.55 mm, 1.1 mm, and 1.5 mm. The issue of flowing air around a radiator with a mass flow rate of 10-3 to 4·10-3 кг/с and a temperature of 293 K was solved. The radiator was heated using a heater, whose temperature was set from 323 to 353 K. Changes in heat flow, pressure drop, and energy efficiency indicator were shown depending on the air mass flow, according to the calculation results. The research findings indicate that the radiator featuring round fillet profiles and a depth of 1.65 mm exhibits the highest heat flow and energy efficiency indicators, as well as the lowest pressure drop.

Keywords: radiator, cooling system, numerical modeling, computational fluid dynamics, heat transfer, heat flow, pressure drop, energy efficiency, calculation, electronics

Using numerical simulation, particle deposition in a porous heat exchanger was studied; the mechanism of sediment formation was sinvestigated, and the influence of sediment on the heat flow was assessed. The influence of porous heat exchanger length, dust particle size, and air flow velocity on particle deposition efficiency, particle breakthrough, and heat flux value was studied. Research results have shown that with increasing length of the heat exchanger, the efficiency of dust particle deposition increases, which leads to the formation of sediment. In turn, the sediment reduces the value of the heat flow from the porous heat exchanger. Depending on the length of the heat exchanger and air velocity, the reduction in heat flow is 3.43-7.27%.

Keywords: porous media, heat exchanger, particle deposition, deposition efficiency, particle breakthrough, sediment, heat flow, numerical modeling, computational fluid dynamics, calculation

The article discusses methods for optimizing floating point calculations on microcontroller devices. Hardware and software methods for accelerating calculations are considered. Algorithms of Karatsuba and Schönhage-Strassen for the multiplication operation are given. A method for replacing floating-point calculations with integer calculations is proposed. Describes how to use fixed point instead of floating point. The option of using hash memory and code optimization is considered. The results of measuring calculations on the AVR microcontroller are presented.

Keywords: floating point calculations, fixed point calculations, microcontroller, AVR, ARM

Using numerical modeling, we performed studies of the influence of the angle of inclination of the plates of the regenerative heat exchanger element on the heating time and pressure drop. The studies were conducted for models of heat exchange elements with lengths of 6 and 20 mm. Depending on the length of the element, the angle of inclination of the plates was: 10°, 20°, 30°, 40° (at L=6 mm) and 3°, 6°, 9°, 12° (at L=20 mm). At the boundary of the calculation area, the air flow velocity and temperature were established, namely 1 and 3 m/s, and 303 and 973 K. The research results demonstrated that increasing the angle of inclination of the plates helped reduce the heating time of the regenerator by 38.56-49.1%, depending on the length of the heat exchange element, the speed and temperature of the air flow.

Keywords: heat recovery, honeycomb heat exchanger, numerical modeling, calculation, heating time, pressure drop, heat exchanger geometry, angle of plate, air flow velocity, air flow temperature

Using numerical simulation, we carried out studies on the effect of the length of a porous heat exchanger on the deposition of dust particles. The heat exchanger models with lengths of 5, 10, 20 and 30 mm were the subject of the studies. At the boundaries of the computational domain, we set the air velocity at 0.1, 1, and 5 m/s and the diameter of dust particles from 10-7 to 10-4 m. Research results have shown that with increasing length of the porous heat exchanger, the efficiency of dust particle deposition increases. This can lead to a decrease in the thermal and hydraulic characteristics of the heat exchanger.

Keywords: porous media, heat exchanger, numerical simulation, calculation, deposition of dust particles, heat exchanger length, air flow velocity, particle diameter, air cooling, microelectronics

The article discusses a graphical notation using three-dimensional visualization for representing models of automated systems according to the Methodology of Automation of Intellectual Labor (MAIL). The research aims to enhance the efficiency of modeling automated systems by providing a more comprehensive representation of the models. Research methods employed include a systems approach. The study results in the formulation of descriptions and rules for creating the corresponding graphical notation for the initial and conceptual modeling stages of subject tasks in MAIL, as well as rules for forming representations for static and dynamic model structures and representing their interrelations. Additionally, rules for visually highlighting and concealing elements within the diagrams of the graphical notation are examined, rendering it suitable for implementation as a software module with a graphical interface for CASE tools, facilitating modeling according to MAIL. Such an approach enables the visualization of the model as a whole and enhances the efficiency of analysts conducting modeling following the methodology.

Keywords: methodology of Automation of Intellectual Labor, modeling of automated systems, conceptual modeling, graphical notation, three-dimensional visualization

This article reveals a number of examples of the features of the construction of the base of a gravity offshore platform used for the extraction of hydrocarbons. The design of the reinforced concrete base of the platform in the form of a "monopod" consisting of 8 lower cylindrical tanks and a vertical reinforced concrete support with a length of 95 m is considered. Reinforcement of the entire structure was carried out by pre-tensioning reinforcement ropes on the hardened concrete in height by mechanical means. During the construction of the gravity foundation, new compositions of heavy high-strength modified concretes with the use of microsilicon and nanocarbon additives were used. During the construction process, adjustable formwork was used along the entire height of the structure.

Keywords: gravity platform base, monopod, pre-tension on concrete, high-strength modified concrete, towing, positioning