High-current semiconductor polycrystalline thermistors of high power of coaxial type have a large mass and consequently, considerable heat capacity and heat resistance. Due to this, the thermophysical and electrophysical processes in them are different in the steady and transient regimes, which is especially important in regimes. which lasts a fraction or a unit of seconds. The main variants of operation of such thermistors in dynamic modes are considered and various characteristics are given.
Keywords: Thermistor, thermal and electrophysical characteristics, electric motors, electrophysical and thermal characteristics of semiconductor thermo-resistors of coaxial type
In this article, the object of the study are the types of recuperators used in air handling units in order to compare their efficiency and payback period. Heat exchanger-a heat exchanger of surface type for the use of waste gas heat, in which the heat exchange between the heat carriers is carried out continuously through the wall separating them. Depending on the temperature of the flows, their rotation speed and rotor speed, we determine the efficiency of the recuperator. Payback of the heat exchanger depends on the climatic parameters of the region, its efficiency, the type of coolant and ventilation mode during the day.
Keywords: heat exchanger, heat exchange, moisture exchange, cold exchange, coolant, plate, rotary, heat pump, efficiency, energy consumption, heater, payback
Annotation: Several ways of utilizing the generated heat, produced by the final gas of boiler unit are analyzed in this article. The first method consists of implementing of heat pump into the process flow diagram of boiler-house plant. The second method encompasses the implementation of axifugal dry box into the process flow diagram. The dry box is implemented into the smoke removal system and also serves as axifugal smoke exhauster. The most widespread method is copious cooling of combustion product gas in steam condensing plants. The copious cooling of smokestack exhaust gases in steam condensing plants allows the full incorporation of sensible heat of smokestack exhaust gases (low heat value). The copious cooling allows the extraction of condensation heat of moistere vapours. The result would be the increasing ratio of utilization of boiler unit by 10-12 percent in optimum performance [ 5,6]. The implementation of steam condensing plant allows to decrease the concentration of nitrogen oxide in smokestack exhaust gases. The same effect can be achieved by implementation of heat pump plant. The efficiency of project implementation of steam condensing plant installation depends to a greater extent on the measure of the amount of hours of operation on peak capacity in recycling mode [6]. Therefore, the way of optimization of boiler flow diagram with the implementation of steam condensing plant, is suggested. This article contains calculations and technical and economic assessment of implementation heat-exchange facility, installed on bypass pipe of opetational block-modulator boiler-house plant with capability of 0,2 Gcal/hr, located in Spassk [4].
Keywords: Boiler-house plant, Steam condensing plant, final gas, heating agent, heat supply system, heat recovery unit, process flow diagram of boiler-house plant, optimization, boiler unit, smokestack exhaust gases, heat producing plant, condensing, heat-exchange
The paper is devoted to the actual problem of ensuring the information security of web-sites. It discusses a method for detecting intentional threats to the confidentiality of information as a result of unauthorized access and is manifested in the form of atypical requests to resources by users. The paper proposes a method based on data mining. Its essence lies in the classification of users' behavior on the basis of information about their actions using an artificial neural network. As a basis for the implementation of the proposed tools, site security audit tools are used as a source of information. The structure of neural network, training methods and practical application are described, and the effectiveness of the proposed methods is evaluated.
Keywords: Data mining, artificial neural network, web-design, machine learning, classification
The problem of the propagation of nonlinear surface waves in a magnetized liquid of infinite depth is solved. The dependence of the frequency of wave oscillations on the magnitude of the magnetic field strength is shown in the graphs. Trajectories of motion of particles of liquid are found. The effect of a magnetic field on the height of a wave is investigated. The results of the study can be used to calculate various technical devices and technological processes.
Keywords: surface waves, magnetizable liquid, magnetic field, wave number, frequency of wave oscillation, magnetic field intensity
When modeling the transport of hot carriers in strong electric fields and using various mathematical relationships describing these processes, usually do not take into account inhomogeneities of impurity doping, which affect the field distribution and the density of the output current. In this paper, we calculated the field distribution along the length of the diode chip. In this case, a one-dimensional model and a phenomenological approach to the description of carrier behavior were used. The results obtained allow one to estimate the influence of the inhomogeneity on the operating modes of the Gunn diode and can be used to create models of higher orders.
Keywords: Gunn diode, numerical modeling, heterogeneity doping physical topological model
A model of corruption based on the example of an examination is psesented as a game in extended form. Both specific values of payoffs and a general case are considered. A probabilistic setup of the problem is also proposed.
Keywords: games in extended form, identification of models, economic corruption
The paper deals with the study of the dynamic characteristics of the coating farm. Due to the changes in the company's technological regulations, it became necessary to install additional ventilation equipment with its output to the roof of the shop. The study showed that to ensure safe operation in the structural scheme of bearing structures it is necessary to organize additional units. Dynamic load on the supporting structures is created by the operation of ventilation equipment. The spectrum of natural oscillation frequencies is determined. The values of these frequencies were compared with the frequency of forced oscillations of the fans. Graphs of the changes in natural frequencies when the fan operating frequency. According to the chart, when the frequency of the driving force coincides with the frequency of natural oscillations, the inertia forces increase sharply, which indicates the passage of the resonance zone. A study of changes in dynamic forces due to rotor imbalance was conducted. The value of the gap arising at wear of bearings at which there will be a destruction of a basic element of a farm was calculated.
Keywords: vibrations, forced vibrations, frequency, resonance, truss
The article is devoted to the analysis of emergency situations related to the damage of gas-insulated switches on ultrahigh-voltage lines. The results of mathematical modeling of aperiodic oscillatory process produced in the Simulink system, which occurs when a high-voltage power line containing shunt reactors is switched on under the nominal voltage, are presented. The variants of using a switch with a set of pre-switched resistors in order to minimize the destructive influence of the aperiodic process that occurs when an overvoltage pulse occurs are considered. The results of the simulation of the switching process in the application of high-voltage switches with a set of pre-switched resistors. The simulation was performed on the parameters of the current transmission line with a nominal voltage of 500 kV on the site of the substation "Eletskaya" - nuclear power plant "Donskaya".
Keywords: shunt reactor, aperiodic process, high-voltage power lines
At present, there is a tendency in Russian society, which is connected with the fact that modern people strive, first of all, for self-realization. Very often, in the process of forming career strategies, a person thinks about whether he is happy in his position after having worked in an organization for over a year. Sometimes, such thoughts force a person to change the type of activity or completely change the place of work. Thus, such a pattern of behavior as downshifting can be formed, when a person radically changes the quality of his life, life priorities and value orientations. The author of the article, in connection with such a change in the model of career behavior, considers the reasons that can influence the reorientation of value orientations from material to spiritual.
Keywords: downshifting, career downshifting, success, values, profession, income, chronic fatigue, yuppie, freelancing, family, freedom
Numerical modeling of the temperature distribution during heating (annealing) by a pulsed Nd: YAG laser of an amorphous silicon (a-Si) film on the surface of an AZO glass substrate is carried out. The simulation was performed on the basis of a numerical solution of the heat equation in the Matlab program to determine the energy density of the laser radiation necessary for crystallization of the a-Si film. For a wavelength of 1064 nm, it was obtained that the temperature at the surface of the a-Si film reaches a maximum value at a time point of 146 ns with a laser pulse with a Gaussian time-shape. It is shown that for the crystallization of an a-Si film with a thickness of about 800 nm with laser radiation with a nanosecond pulse duration, the optimum energy density is 600-700 mJ / cm2 when the temperature across the thickness of the a-Si film corresponds to 550-1250 ° C.
Keywords: Numerical simulation, laser annealing, temperature distribution, a-Si film, solar cell
This article will analyze the effect of Gc on the propagation of cracks in glasses with different material properties. The analysis demonstrated that with decreasing Gc, the crack length will increase and, with a larger applied force, the effect of Gc on the crack propagation in the structure decreases.
Keywords: fracture mechanics, fats fracture, Gc, crack propagation, Code_Aster, Solome Meca
The article presents a theoretical description and procedure for calculating the three-hinged arch parabolic outline. The technique of creation of the universal program in a computing complex of Mathcad for various options of vertical loading is in detail stated. The method of calculation of a three-hinged statically determined arch is considered in detail. The order of design calculation is given in the article. The technique of the automated creation of diagrams of internal power factors of an arch design is offered. A detailed description and analysis of the design scheme of three-hinged arch is given.
Keywords: three-hinged arch, statically definable arches, arched structures, parabolic outline, diagrams of internal power factor
The paper describes the process of developing a web application that contains audio content. When designing the system, the methodology of OOAP (Object-Oriented Analysis and Design) and the MVC (Model View Controller) design pattern were used. With umbrello, canonical UML diagrams are constructed, describing various aspects of the system being modeled. Based on the diagrams created, the application was implemented using the java programming language. Also, the user interface is made, allowing to demonstrate the capabilities of the application. The developed application should be a multi-page client-server application with the ability to listen to music and create playlists based on their preferences.
Keywords: web application; audio content; methodology of object-oriented analysis and design; UML - chart; java programming language
The article is devoted to the close studying of heat transfer and hardening of the ingot in the secondary cooling zone (further SCZ) in the continuous casting machine (further CCM), and also determining a stress-strain state of the ingot including continuously varying temperature field inside it in order to prevent the process of buckling the ingot by setting rollers in the center of the largest displacements and deformations and as a consequence of reducing the length of the roller section. This aim is achieved through the development of methods of calculation of the stress-strain state of the ingot in a CCM with a help of the temperature object decision, correct selection of the approximation model of the experimental data and the selection of finite element-based on the Lagrangian description of motion of a continuous medium and comparison the calculation results for multiple selected sections.
Keywords: continuous casting machine, ingot, hardening in the secondary cooling zone, rollers, heat-exchange