Electrodynamic modeling of a pipeline linear section with leakage

2020 ◽  
Author(s):  
Yu. K. Shlyk ◽  
Yu. A. Vedernikova ◽  
S. Yu. Bondarenko
Keyword(s):  
Linear Section ◽  
Electrodynamic Modeling

The method of determining the metrological performance of unit reference standards of reflection coefficient in waveguides at millimeter waves

2020 ◽  
pp. 59-63
Author(s):  
A.S. Bondarenko ◽  
A.S. Borovkov ◽  
I.M. Malay ◽  
V.A. Semyonov
Keyword(s):  
Reflection Coefficient ◽  
Millimeter Waves ◽  
Primary Standard ◽  
Reference Standards ◽  
Measurement Scale ◽  
Current State ◽  
Coefficient Measurement ◽  
Mathematical Equations ◽  
Electrodynamic Modeling ◽  
Metrological Performance

The analysis of the current state of the reflection coefficient measurements in waveguides at millimeter waves is carried out. An approach for solving the problem of reproducing the reflection coefficient measurement scale is proposed. Mathematical equations, which are the basis of the reflection coefficient measurement equation are obtained. The method of determining the metrological performance of reflection coefficient unit’s reference standards is developed. The results of electrodynamic modeling and analytical calculations by the developed method are compared. It is shown that this method can be used for reproducing the reflection coefficient unit in the development of the State primary standard.

Amplitude-phase coordinate characteristic of the main pipeline linear section

2019 ◽  
pp. 20-24 ◽  
Author(s):  
Yu.K. Shlyk ◽  
◽  
Yu.A. Vedernikova ◽  
S.Yu. Bondarenko ◽  
◽  
...  
Keyword(s):  
Main Pipeline ◽  
Linear Section

Features of nonlinear in-plane shear deformation of a unidirectional and orthogonally reinforced polymer sheets of composite materials

2021 ◽  
Vol 87 (5) ◽  
pp. 47-55
Author(s):  
A. O. Polovyi ◽  
N. V. Matiushevski ◽  
N. G. Lisachenko
Keyword(s):  
Experimental Data ◽  
Composite Materials ◽  
Shear Modulus ◽  
Maximum Deviation ◽  
Linear Section ◽  
Stress Strain ◽  
Plane Shear ◽  
End Point ◽  
Reinforced Polymer ◽  
Failure Point

A comparative analysis of typical stress-strain diagrams obtained for in-plain shear of the 25 unidirectional and cross-ply reinforced polymer matrix composites under quasi-static loading was carried out. Three of them were tested in the framework of this study, and the experimental data on other materials were taken from the literature. The analysis of the generalized shear-strength curves showed that most of the tested materials exhibit the similar deformation pattern depending on their initial shear modulus: a linear section is observed at the beginning of loading, whereas further increase of the load decreases the slope of the curve reaching the minimum in the failure point. For the three parameters (end point the linear part, maximum reduced deviation of the diagram, tangent shear modulus at the failure point) characterizing the individual features of the presented stress-strain diagrams, approximating their dependences on the value of the reduced initial shear modulus are obtained. At the characteristic points of the deformation diagrams, boundary conditions are determined that can be used to find the parameters of the approximating functions. A condition is proposed for determination of the end point of the linear section on the experimental stress-strain curve, according to which the maximum deviation between the experimental and calculated (according to Hooke’s law) values of the shear stress in this section is no more than 1%, thus ensuring rather high accuracy of approximation on the linear section of the diagram. The results of this study are recommended to use when developing universal and relatively simple in structure approximating functions that take into account the characteristic properties of the experimental curves of deformation of polymer composite materials under in-plane shear of the sheet. The minimum set of experimental data is required to determine the parameters of these functions.

Calculation of the impedance characteristics of a microstrip loop antenna with a metallized dielectric substrate

2021 ◽  
Author(s):  
S.A. Korshunov
Keyword(s):  
Mathematical Models ◽  
Current Density ◽  
Mathematical Problem ◽  
Current Density Distribution ◽  
Dielectric Substrate ◽  
Microstrip Antennas ◽  
Radial Component ◽  
Method Of Integral Equations ◽  
Electrodynamic Modeling ◽  
Rigorous Model

In connection with the intensive development of electronic technology, an urgent task is the development of antennas in a microstrip way, the advantages of which are small dimensions, a relatively simple manufacturing technology, and the ability to control their characteristics by using various materials and forms of radiators in their design. Currently, there are many mathematical models of microstrip antennas with vibrator radiators located on dielectric substrates, while models of microstrip antennas with other radiator shapes are presented much less often. As a rule, the calculation of the characteristics of such antennas is performed in electrodynamic modeling systems based on the use of «closed» algorithms. In this regard, there is a need to develop rigorous mathematical models of microstrip antennas with radiators of various shapes. This work is dedicated to the development of a rigorous model of a microstrip antenna with a frame radiator located on a dielectric substrate, based on the use of the method of integral equations. An integral equation is obtained for the unknown distribution function of the radial component of the current density over a frame radiator, the numerical solution of which is a correct mathematical problem. In addition, the numerical results of calculating the current density distribution, as well as the input impedance of such an antenna for various parameters of the radiator and substrate, are presented.

Laboratory plant for evaluation of burnout rate of various materials

2021 ◽  
pp. 19-23
Author(s):  
Н.П. Копылов ◽  
Е.Ю. Сушкина ◽  
В.И. Новикова ◽  
В.В. Яшин
Keyword(s):  
Induction Period ◽  
Flame Retardant ◽  
Polyurethane Foam ◽  
Beech Wood ◽  
Polyurethane Foams ◽  
Air Flow Rate ◽  
Linear Section ◽  
Significant Discrepancy ◽  
Burnout Rate ◽  
Burn Rate

Описана методика исследования скорости выгорания различных материалов. Для реализации методики создана лабораторная установка. Экспериментально установлено, что процесс выгорания материалов зависит от температуры реактора и скорости воздушного потока. Кривая выгорания имеет S-образный вид и три характерных участка: индукционный период, линейный участок и участок реакции, где происходит выгорание углеродистого остатка. В табличной форме представлены результаты исследования некоторых широко распространенных материалов. The article describes a method for studying the burnout rate of various materials. There was created the laboratory plant for implementation of the method. It is experimentally established that the process of burnout of materials depends on the temperature of the reactor and the air flow rate. The burn-up curve has an S-shape and three characteristic sections: the induction period, the linear section, and the reaction section where the carbon residue burns out. The article presents the results of study of some widely distributed materials in tabular form. The mass burn rate of beech wood is 1.5 times higher than that one of pine. Perhaps this is due to the impregnation of beech with furniture varnish, since the sample was part of the furniture lining. It is noteworthy that significant discrepancy in the burn-up rates was obtained during combustion of samples of different brands of polyurethane foams. So, for hard polyurethane foam - “izolan 2”, which has a flame retardant in its composition, burnout curves with longer induction period are obtained (as a result of flame retardant action). However, the burnout rate is higher in comparison with soft polyurethane foam without flame retardant (foam rubber). The composition of the material “isolan-2”. Rubber also has a long induction period, but a high burnout rate.

STUDY OF THE INFLUENCE OF RFID TAG BENDING ON BASIC CHARACTERISTICS

2021 ◽  
pp. 85-89
Author(s):  
С.М. Фёдоров ◽  
Е.А. Ищенко ◽  
Е.В. Папина ◽  
К.А. Бердников ◽  
Ю.Д. Савкина
Keyword(s):  
Flexible Substrate ◽  
Passive Mode ◽  
Rfid Tag ◽  
Active Mode ◽  
Effective Scattering Area ◽  
Frequency Peak ◽  
Detection Mode ◽  
Basic Characteristics ◽  
Electrodynamic Modeling ◽  
Passive Rfid

Рассматривается пассивная радиочастотная метка, которая находится на гибкой подложке, что приводит к появлению проблемы с изменением характеристик при изгибе метки. В процессе исследования производилось моделирование для трех ситуаций: плоской метки, изогнутой внутрь и наружу. Благодаря современным методам электродинамического моделирования возможно определить все основные характеристики RFID метки - в активном режиме: обратные потери, диаграмму направленности; в пассивном режиме: диаграмму обратного рассеяния, токи и напряжения в нагрузке. При моделировании были построены графики зависимости амплитуд токов и напряжений в нагрузке от частоты, пиковые значения эффективной площади рассеяния. Благодаря полученным данным можно определить наиболее оптимальные частоты для облучения RFID метки, чтобы обеспечить ее работу в активном режиме (высокие токи и напряжения в нагрузке), а также в режиме обнаружения - большие значения ЭПР. Приводятся графики и таблицы для сравнения исследуемых случаев, по которым видны изменения характеристик при изгибе метки, что делает невозможным применение системы в широких диапазонах частот, так как стоит учитывать ее возможные изгибы The article discusses a passive RFID tag that sits on a flexible substrate, which leads to a problem with changing characteristics when the tag is bent. In the course of the study, we carried out modeling for three situations: a flat tag, curved inward and outward. Thanks to modern methods of electrodynamic modeling, it is possible to determine all the main characteristics of an RFID tag - in the active mode: return loss, radiation pattern; in passive mode: diagram of backscatter, currents and voltages in the load. During the simulation, we plotted graphs of the dependence of the amplitudes of currents and voltages in the load on frequency, peak values of the effective scattering area. Thanks to the data obtained, it is possible to determine the most optimal frequencies for irradiation of an RFID tag in order to ensure its operation in an active mode (high currents and voltages in the load), as well as in the detection mode - large ESR values. The article provides graphs and tables for comparing the cases under study, which show changes in characteristics when the tag is bent, which makes it impossible to use the system in wide frequency ranges, since its possible bends should be taken into account

Multifrequency optimization method of measurement the frequency dependency of electrophysical parameters of dielectric and magnetodielectric coatings

2021 ◽  
pp. 54-61
Author(s):  
Aleksandr I. Kaz'min
Keyword(s):  
Frequency Dependence ◽  
Radio Wave ◽  
Optimization Method ◽  
Metal Substrate ◽  
Geometric Parameters ◽  
Microwave Range ◽  
Electrodynamic Modeling ◽  
Wave Methods ◽  
Electrophysical Parameters

The issues of experimental determination of electrodynamic parameters of existing and new synthesized materials and coatings used in the microwave range are highlighted. Problems arising from measurements of the electrophysical and geometric parameters of dielectric and magnetodielectric coatings, taking into account their placement on a metal substrate, by radio wave methods are considered. We present the new radio wave method of joint measurements of the frequency dependence of the complex permittivity, the frequency dependence of the complex magnetic permeability, and the thickness of plane-layered samples of dielectric and magnetodielectric coatings on a metal substrate. Determination of electrophysical and geometric parameters of the coating in the proposed method is reduced to minimizing the objective function constructed based on the discrepancy between the experimental and design theoretical values of the attenuation coefficients of surface electromagnetic wave fields on a grid of discrete frequencies. The simulation model of measurements is shown, implemented on the basis of the electrodynamic modeling system CST Microwave studio (Simulia corporation, USA) and the Matlab system. The results of simulation are presented to determine the frequency dependences of the electrophysical parameters and the thickness of a sample of a radio-absorbing coating on a metal substrate. Errors in the estimates of permittivity and permeability in the measurement frequency band 9–13.5 GHz, which are no more than 10 % with a confidence level of 0.95 with a mean square deviation of the noise level of 0.006, have been obtained. The proposed method can be in demand in various science-intensive areas – microelectronic, aerospace, mechanical engineering, etc.

scholarly journals The interstellar extinction curve from 4000 Å to 6500 Å

1970 ◽  
Vol 36 ◽  
pp. 52-56
Author(s):  
G. A. H. Walker ◽  
J. B. Hutchings ◽  
P. F. Younger
Keyword(s):  
Interstellar Extinction ◽  
Absorption Peak ◽  
Extinction Curve ◽  
Linear Section ◽  
Broad Absorption ◽  
Diffuse Interstellar Bands

Interstellar extinction curves (mext vs. 1/λ) of 20 Å resolution have been obtained at the DAO from photoelectric scanner observations in the range 4000 Å to 5000 Å for five stars, and of 50 Å resolution for four stars in the range 4000 Å to 6500 Å from Willstrop's photoelectric data. There is a closely linear section between 4900 Å and 5800 Å for all of the curves. There are changes of gradient or discontinuities associated with the broadest diffuse interstellar bands at 6180 Å, 4882 Å, 4761 Å and 4430 Å. There is a marked discontinuity near 5800 Å and for some stars a broad absorption near 4200 Å. The 4430 Å band lies between two unequal wings of anomalously low extinction (one of which has been detected at Edinburgh). The irregularities vary from star to star, and those in the neighbourhood of the 4430 Å band seem to have the same form as those in the region of the absorption peak at 2200 Å

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