The article is considered the wall stability of a steel cylindrical pre-stressed granary, compressed by the friction forces of grain and shell, taking into consideration the influence of the grain internal pressure, its elastic resistance from the inside and the elastic resistance of the pre-stressed shell outside. In this case, the initial and subcritical deflection of the shell is assumed to be axisymmetric, and the loss of the shell stability occurs with the formation of asymmetric deflection. The given solution of the problem allows to determine the magnitude of the critical efforts taking into consideration the influence of the grain internal pressure, its elastic repulsion, the magnitude of the initial deflections and the ratio of shell dimensions.
Keywords: stability calculation, wall stability, prestressing, internal lateral pressure, elastic rebound
Automation of agriculture is currently a promising and actively developing branch of robotics. At the moment, there are many foreign analogues offering ready-made solutions for automatic control of sowing crops. However, in Russia, most of the sowing is carried out on mechanized plants under the mandatory supervision of a highly qualified specialist in the maintenance of the plant.
Keywords: seeding control, microprocessor system, selection, seeding algorithm, system architecture, hardware, system structure, layout base, management methodology, import substitution
Cementation studies focus almost exclusively on the movement of carbon, described through the diffusion equations, often with constant coefficients and without regard to temperature. This approach does not allow, to take into account the further diffusion of carbon into the workpiece in a lower temperature range at the stage preceding quenching. The paper describes the modeling of the diffusion saturation of steel by carbon in the cementation process, taking into account the influence of temperature on the example of a numerical solution of the gear cementation problem using the COMSOL Multiphysics program. It was shown that the finite element mathematical calculation of the process of saturation of austenite with carbon during cementation gives good agreement with experimental data, and finite element analysis methods can be used for multivariate calculation of the carbon content in austenite after diffusion saturation
Keywords: carbon diffusion, carburization, COMSOL Multiphysics, numerical modeling, carbon distribution, carburization, Fick diffusion law, mass transfer, heat transfer, gear, finite element method
A method for the quasi-optimal synthesis of a multi-mode synchronization system based on the maximum condition of the generalized power function has been developed. The effectiveness of its operation in capture mode is demonstrated on the basis of mathematical modeling. The results showed high resistance to disturbances and a decrease in the synchronization error of the multimode system in the steady state.
Keywords: phase locked loop, combined maximum principle, multi-mode control
The article discusses the methodology and concept of situation rooms. The methodology and concept of situation rooms has a long history. As a first step, one can recall the methodology of a classic board in Cretaceous technology. Smart boards have now emerged, where hardware and software are present alongside the light pencil, to display various kinds of information. The second level in cognitive modeling systems is the collective panel display of various information products. Finally, the third level of situation rooms implies a significant development of the software and hardware of the decision-maker support complex. The high level of complexity of the third stage in the creation of the situation room is the creation of developed mathematical support in brainstorming tasks, as well as in the provision of analysis of weakly structured systems. However, while our work deals with the creation of a theoretical model of semantic identification of various scenes, situations of the person making the decision.
Keywords: Information collection and display system, decision maker, electronic counteraction
During the year, depending on the latitude and climatic zone, the number of thunderstorms and their intensity vary greatly, these parameters decrease to the Northern latitudes due to a decrease in humidity and temperature and, accordingly, a decrease in the probability of forming conditions for the formation of convective and thunderstorm clouds. The article deals with the mechanisms of dangerous effects of lightning discharges. The electric parameters of the discharges for thunderstorm processes in the atmosphere were studied using data from the geophysical monitoring center of the FGIBU "VGI", which includes a network of sensors of the automatic thunder-gauge finder - the range finder LS8000. The results of the analysis of the recording of ground-discharge currents and the time of their growth obtained during the period of its operation are presented. The authors determined the statistical distributions of the lightning current amplitude. It is established that the discharge parameters in different regions differ and can change with time. This means that for the effective operation of lightning protection systems and the implementation of measures to ensure life safety during thunderstorms, it is necessary to monitor the lightning situation in each individual region.
Keywords: atmospheric electricity, lightning discharges, lightning guides, lightning protection measures, life safety
This article may be of interest to researchers who are designing new machine systems for felling-area works with autonomous energy supply. A methodology based on the decomposition method for creating an simulation functional model of a system consisting of a mobile wood chipper for felling-area works and a mobile energy module is proposed. The machine system of interest is an original technical solution. It consists of an autonomous energy supply module with powered by wood fuel external combustion engine and a logging machine for the production of wood chips. The functioning equipment units of the system is simulated using the MATLAB Simulink dynamic simulation environment. For the convenience of experiments, the use of LabVIEW virtual instruments is proposed for setting input and control parameters, as well as displaying output parameters. The input, control, disturbing and output parameters of each functional block of the system are described: gas generator, external combustion engine, electric generator, uninterruptible power supply, electric motor, propulsion device, wood chipper unit, hydraulic manipulator. It is supposed to use this simulation model to justify the main parameters of the autonomous system for the production of wood chips, as well as the further development of an automated control system.
Keywords: fuel chips, wood fuel, unmerchantable tree, simulation model, LabVIEW, Simulink, mobile chipper, autonomous power supply, logging
This article presents the results of monitoring the operational reliability of the on-farm network of rice irrigation systems. The issues of planning and prospects for its improvement on the basis of the introduction of modern laser scanning systems and digital a control systems are considered. In the Krasnodar Territory, the main consumer of water resources is agriculture, which absolutely prevails in terms of water withdrawal among other consumers. The most expensive water resource is the rice water industry. Its share is about 90% of the total water consumption in agriculture. To prevent degradation of the ecosystem of the river. Kuban and achieving the objectives of the Water Strategy by 2020, irrevocable water withdrawal must, at a minimum, be stopped at the achieved level. Satisfying growing water needs and introducing new water users should be implemented through water conservation in the systems of existing water users.
Keywords: monitoring, residual resource, rational water use, water resources, on-farm network facilities, rice irrigation systems, technical condition
The work is a continuation of the study of cable-stayed roofs of large-span sports buildings, it focuses on the technological aspect of the construction of stadiums and sports palaces. Due to the introduced criterion of the location of the assembly of structures, the systematization of technologies for the construction of facilities currently commissioned has been carried out. The result of the work is a comparative table that allows to rationalize the choice of methods of pre-assembly and installation.
Keywords: cable-stayed covering, large-span building, steel cable, cable, pylon, sports building, stadium, hanging roof, cable installation, pre-assembly, jack, disassembly of scaffolding
The paper focuses on energy efficient reconstruction of construction systems by means of their upward extension using modular spatial structures. It is further noted that the existing contradictory definition of the term “modular structures” necessitates classifying modular structural elements by spatial dimension, type and size, weight, degree of prefabrication, constructability and environmental safety. A list of the world’s leading manufacturers is provided featuring modular spatial structures to be used in the construction of new buildings and reconstruction of existing buildings. Also, the paper underlines the importance of using added stories in making modular roof structures of lightweight metallic structures (LMS) and lightweight thin-wall steel structures (LTSS) and provides an overview of the main types of modules, pointing out the key benefits of modular structures.
Keywords: modular building structures, energy efficient reconstruction, upward construction, structural and non-structural modules, constructability
A method for the intellectualization of measurement procedures has been developed. It is based on the step-by-step optimization procedure, which provides a reduction of the stochastic estimation problem to a number of deterministic problems. The task of the first stage of optimization is the synthesis of an adaptive mathematical model of the measuring process based on the combined principle of maximum, which, unlike the known methods, will ensure the constructiveness of its use in the next stages of optimization. The task of the subsequent stages of optimization is to solve the estimation problem based on the regularization method A.N. Tikhonov. Equations of an iterative measurement procedure are obtained that differ from the state transition vector functions known in structure. It belongs to the category of intelligent measuring procedures, since it makes a targeted choice of the closest to the true value of the assessment of the measured parameter in the conditions of structural uncertainty of the model of the studied object and parametric uncertainty of the observation model.
Keywords: two-stage synthesis, intellectualization, the combined principle of maximum, regularization
Phantoms are an imitation of biological tissue. With the help of phantoms, it is possible to simulate the propagation of light in biological tissue. During any biophysical experiments there is a need for the constancy of the initial conditions of the experiment. The use of solid phantoms that do not degrade over time and under the influence of external factors is the Foundation for reliable results and repeatability of the experiment. The creation of phantoms of biological tissue containing fluorescent nanoparticles or nanoparticles with high absorption, and which correspond to specific mechanical or optical properties, is an urgent task. The paper describes the development, fabrication and characterization of solid tissue phantoms containing gold and upconversion nanoparticles. Optical and mechanical properties of phantoms are studied. The temperature range suitable for the use of samples as phantoms of biological tissue for laser thermolysis problems was revealed.
Keywords: phantom, gold nanorods, luminescence, quantum dots, thermogravimetric analysis
The paper presents an analytical description of the unfolding surface of one of the products of light industry – aerodynamic shape. All surface elements are designed in the Maple environment based on the 4GL package commands. A set of commands allowing to describe surfaces and spatial curves analytically is proposed for the construction of 3D graphical objects. Elements sweep aerodynamic shape are conical and cylindrical sweep with a special character of their boundaries. The proposed description of the surface of the air shape allows you to design a technical product of specified geometric dimensions according to the calculated geometry of the elements of the air shape.
Keywords: description of the spatial shape of aero figures, Maple 2015 package, 3D graphic objects of conical and cylindrical types, 2D scanning
This article discusses strategies for the introduction and development of BIM technologies in a number of leading countries in this area. Based on the analysis of literature and other sources, the main factors influencing the BIM implementation process are highlighted. As a result, it was concluded that the role of the state in the implementation of BIM is quite high. Countries in which BIM is implemented with government support will succeed more quickly and more likely.
Keywords: BIM, information modeling, implementation, implementation strategies
The paper presents an analysis of stadiums with cable-stayed roof, in the context of progressive solutions used in various construction cycles. On the basis of the systematization carried out, the directions of the rational use of the identified methods of reducing material consumption and deformability, increasing the rigidity, stability of structures, improving the efficiency of installation work have been highlighted.
Keywords: cable-stayed roof, long-span building, steel cable, aerodynamics, cable-stray, pylon, sports object, stadium, hanging roof, translucent roofing, light opening roof, monitoring system of the technical condition of the object, cable roof mounting