When erythrocytes move along a narrow capillary, they take an asymmetric shape and roll along the capillary like a tractor caterpillar (tank - treading motion). The shape of the erythrocyte is approximated by a truncated cylinder and is uniquely determined by the diameter of the erythrocyte in the capillary, the volume and surface area of the erythrocyte. Other input parameters are the speed of the erythrocyte in the capillary, the frequency of rotation of the erythrocyte membrane, the charge of the erythrocyte, and the number of closed trajectories along which the charges move. It is assumed that the negative charges located on the membrane are equal in magnitude and distributed evenly over the membrane and move along closed trajectories together with the membrane. From the last parameters, you can find the number of charges on the erythrocyte membrane. According to the Biot-Savart-Laplace law, mobile charges generate a magnetic field in the surrounding space. Using computer calculations, the distributions of the magnetic field strength were obtained both near a single erythrocyte rolling along a narrow capillary, and near a capillary along which several erythrocytes move, at various values of hematocrit. The dependence of the maximum value of the magnetic field strength near the capillary on the hematocrit is found. In particular, it was shown that at a distance from the capillary equal to 8 capillary diameters, the maximum value of the magnetic field strength increases by a factor of 1.29–1.36 (depending on direction) with increasing hematocrit from 12.27% to 18.25%.
Keywords: mathematical model, magnetic field, charge, membrane, erythrocyte, capillary, hematocrit
The article is devoted to mathematical modeling of construction of underwater tunnels intended for subway. This type of tunnels can also be used as railway and road tunnels. The most interesting are underwater tunnels-bridges and floating tunnels, but the most perspective and most frequent are tunnels located at the bottom of water barrier.
Keywords: underwater tunnel, subway, finite element method, leave section method, mathematical modeling, construction technology stages, transport tunnel, stress-strain state
Yemeni cities are urbanizing so rapidly that there will soon be no room for green spaces. In this regard, there is a need to find solutions to provide citizens with the "green" infrastructure necessary for life and health. This article presents the results of an urban planning analysis of the study of existing territorial reserves suitable for the formation of the "green" frame of the city of Ibb, their capacity and structure. Based on the analytical data obtained, the concept of the "green" frame of the city of Ibb was proposed, on the basis of which the system of architectural and urban planning principles for organizing the "green" recreational frame of the Yemeni highland cities was expanded and supplemented.
Keywords: urban planning, urban greening, sustainable development of the city, landscape design, urban environment, reconstruction
This article is devoted to the study of the European experience of designing sustainable architecture in the process of renovation of former port-industrial complexes. The purpose of the study is to identify current trends and approaches to the design of sustainable architecture, taking into account the specifics of the place. The analysis of the experience of Denmark, Sweden and Germany in the transformation of former port-industrial complexes in the context of sustainable architecture is carried out according to a number of criteria: urban planning solution, spatial and architectural planning solution, stylization of the image of new buildings, criteria for energy efficiency and environmental friendliness; economic and social sustainability. The emphasis is placed on the study of the formation of the architectural appearance of buildings. The importance of the interaction of architecture with the environment and context when creating a marine facade is emphasized. The identified design approaches can be used in research, design and educational activities.
Keywords: architecture, building, sustainable, eco-friendly, design, port, industrial, renovation, project, function, facade, context, european, approach
Nitrogen oxides are one of the most common and toxic gaseous air pollutants of large industrial centers. The main difficulty of cleaning gas emissions is related to the dependence of the efficiency of the applied cleaning technologies on the NOx concentration, the frequency of emissions, the need for processing and/or disposal of products of interaction of nitrogen oxides with absorbers and regeneration of catalysts. The article analyzes the features of currently used and promising methods of cleaning waste gases from NOx, systematizes data on the effectiveness of such technologies. Based on the analysis of the processes of formation of nitrogen oxides, rational approaches to reducing NOx emissions in metal etching technology and electroplating are proposed.
Keywords: nitrogen oxides, biogenic and technogenic sources, catalytic and non-catalytic purification, selective purification, absorption purification, comparative efficiency
The article deals with the issues of assessing the effectiveness of the construction and operation of metal corrugated pipes. The characteristic features and difficulties of the operation of corrugated metal culverts in areas of permafrost distribution are revealed. The characteristics of the main defects of culverts are systematized. The features of thermophysical calculations of metal corrugated pipes on a frozen base are analyzed in detail. Recommendations are given on the application of the most effective technical solutions in the construction of corrugated metal culverts on permafrost soils.
Keywords: highway, culverts, metal corrugated pipes, thermal conductivity, permafrost soils
Investigation of ways to accelerate the training of neural networks using genetic algorithms and the study of the dependence of the speed of genetic algorithms on the mutation rate. In this study, a program was implemented on the Unity graphics platform using genetic algorithms and mutations to determine their optimal coefficient. The experiment showed that the learning rate really depends on the mutation rate, and the highest learning rate was obtained at 5-7,5%.
Keywords: machine learning, deep learning, genetic algorithm, optimization, neural network, artificial neuron, mutation, artificial intelligence, non-player character, optimization
The article presents the results of a comparative analysis of practical calculations of driven and bored piles, which have similar geometric parameters and common geological conditions of construction sites. Taking into account the peculiarities of the use of these piles and the available experimental data, the paper analyzes the calculated values of their bearing capacity and gives an engineering assessment of the results of the calculation. The quantitative difference between the determined parameters of the bearing capacity of piles - friction along the lateral surface and frontal resistance, is clearly shown in the constructed diagrams. So, when using the standard values of the coefficients to determine the bearing capacity of piles, we have a significant excess of this parameter for driven piles. The need to use more gentle methods of driving piles to the design depth leads to the possibility of using the technology of arranging bored piles, which have a lower bearing capacity with the same parameters as driven piles. This feature should be taken into account in engineering calculations when selecting the optimal dimensions of bored piles.
Keywords: driven piles, bored piles, geological conditions, engineering calculations, bearing capacity
In the article, the authors examine the problem of ensuring cybersecurity in the modern world in terms of the study of social practices. The implemented cyber attacks are analyzed, and the danger of hacker attacks is shown. With a fair amount of evidence, it can be stated that in the modern world, the risks associated with cyber intrusions can include the loss or disclosure of consumer data, theft or disclosure of intellectual property, as well as the loss of investors as a result of the theft of funds or a decrease in the market value of companies subjected to cyber attacks. It is concluded that cybersecurity is a constantly evolving landscape, and now there is an urgent need to constantly learn from both our own experience and the experience of other companies countering cyber attacks effectively, and it is also important that successful interaction with adversaries in cyberspace requires a constant pursuit of a tactical, operational and strategic initiative.
Keywords: cyber wars, cognitive modeling, cyber attacks, hacker attacks, cyber risks, cyber defense
For the possibility of installing overhead cranes, steel columns of an industrial building are made in steps, with the allocation of crane and crane parts. The basis of the upper and lower parts of the column are steel I-beams with a mismatch of the central axes. As part of the work, variant modeling (using CAD) of a steel column that is part of the U-shaped frames of industrial buildings, consisting of crane and crane parts, was carried out. Various solutions for the difference of the central axes of the crane and crane parts of the column in the model are proposed. The results of static calculation of column elements are obtained. A comparison of the results obtained is made, an analysis of the optimal method of modeling column elements for structural schemes is performed. Based on the calculations performed and the analysis of the results obtained, conclusions are drawn.
Keywords: industrial building, I-beam, finite element method, stress-strain state, node, rod, circuit
The service life of shut-off valves operated at sites of hazardous production facilities with ultra-high parameters of the working environment is largely limited by the wear resistance of contact surfaces. In this regard, to increase the durability of contact surfaces, technological methods are used to modify the surface and special functional coatings are used. The development and selection of new functional coatings are inextricably linked with their comparative study based on the determination of the most significant characteristics through testing. The purpose of this work is an analytical review of the most common test methods for evaluating the characteristics of multicomponent nanocomposite coatings applied to the contact surfaces of valves to increase their wear resistance. Based on the results of the analytical review, recommendations are given for testing multicomponent nanocomposite coatings.
Keywords: pipeline fittings, functional coatings, test methods, service life, wear, friction, hardness, corrosion, tribology
The paper considers the types and classification of industrial PID controllers according to various types and groups. A group of linear controllers has been identified, which includes PID controllers, which are most widely used in various technical devices. Some well-known software systems that provide calculations for PID controllers are given. The transition from the mathematical notation of the trapezoidal expansion of the transfer function of the PID controller, used in the PID Tune option of the Matlab environment, to the equivalent transfer function, represented by the symbolic coefficients of the numerator and denominator polynomials, is shown. A theorem is proved that shows a one-to-one correspondence between the parameters P, I, D of the controller and the coefficients of the resulting transfer function. Flowcharts of algorithms for calculating transfer function coefficients (TF) from known values of controller parameters and calculating transfer function coefficients from known values of controller parameters are given. An illustrative example is considered.
Keywords: PID controller, transfer function, block diagram of the algorithm, Matlab environment
This paper considers the modern classification methods of breast cancer histopathology. The main purpose of the study is to conduct an extended test of the trained model on data that fundamentally differs from the training dataset. We chose a large Russian dataset with different types of classification as the training dataset. The dataset contains images with different resolutions and magnifications. As testing data, the same dataset was used, but the resolution, color balance, brightness, and contrast of the images were changed. The classes in the dataset were unbalanced, so we applied augmentation methods (flipping and rotation). The models ResNet 152, DenseNet 121, Inception_resnet_v2 were selected for training. The transfer learning approach was used for training. The preprocessing of images consisted of normalizing the values of all image channels in the range from 0 to 1. The models had good results with standard testing methods. The resolution change slightly reduced metrics. The change in color balance, brightness, and contrast significantly reduced all metrics. The test results show that elementary normalization is not enough for high-quality training of models resistant to changes in input data.
Keywords: neural network, model, machine learning, breast cancer, cancer classification, artificial intelligence, transfer learning, histopathology
The flow that occurs during the movement of an elevator cabin in the shaft of a high-rise building from the -4th to the 58th floor is considered. The moving elevator cabin works like a piston and pushes air in front of it out of the shaft and draws air into the shaft behind it. This effect is especially significant in high-rise buildings, which are characterized by a high speed of elevator cabins movement. The STAR-CCM+ software was used as a research method. To simulate the non-stationary problem of the elevator cabin movement, the technology of sliding meshes was used. It was found that when the elevator cabin moved at a speed of 7 m/s, the maximum pressure drops formed on the surfaces of the elevator shaft amounted to 130 Pa. It was found that the maximum flow rate of air entering the elevator shaft and from the elevator shaft into the hall due to the piston effect is about 250 m3/h. This value is comparable to the flow rates formed due to natural movement of air in the elevator shaft caused by stack effect in winter and cannot be automatically excluded from consideration.
Keywords: high-rise building, numerical simulation, piston effect, stack effect, elevator shaft
Concrete and reinforced concrete recycling is a system of mechanical processing of waste concrete and reinforced concrete with the aim of obtaining raw materials for secondary use, i.e. resource renewal and returning construction waste to the economic cycle. In order to reduce costs for new construction, preserve natural resources, and land areas that could be used for new landfills, it is necessary to use recycled concrete and reinforced concrete as secondary crushed stone and sand-gravel mixture. At present, the economic necessity has arisen for the development of modern domestic equipment for processing concrete waste. Foreign manufacturers of crushing equipment from unfriendly countries are leaving Russia, which gives an impetus to the active development of this industry in our country, as well as to the emergence of new relationships with companies from countries that previously did not have access to our market.
Keywords: Keywords: recycling, reinforced concrete, secondary crushed stone, construction waste, crushing equipment.