scholarly journals Математична модель антени з нелінійними характеристиками для розрахунку елект-ромагнітного поля у зоні Френеля

2021 ◽  
pp. 46-58
Author(s):  
Дмитро Вячеславович Грецьких ◽  
Василь Олександрович Алєксєєв ◽  
Андрій Володимирович Гомозов ◽  
Віктор Олександрович Катрич ◽  
Михайло Васильович Нестеренко
Keyword(s):  
Mathematical Model ◽  
Electromagnetic Compatibility ◽  
Phase Distribution ◽  
Mutual Influence ◽  
Fresnel Zone ◽  
Nonlinear Effects ◽  
Arbitrary Field ◽  
Mathematical Methods ◽  
Nonlinear Characteristics ◽  
Transmitting Antenna

The paper presents a mathematical model of radio-electronic systems (RES), which include antennas and their excitation paths with nonlinear characteristics. The model provides acceptable accuracy of RES quality indicator analysis and electromagnetic compatibility (EMC) for further practical design. General purpose: the development of a mathematical model of a transmitting multi-input radiating structure with nonlinear characteristics under the Fresnel zone. Objective: choice justification of a structural schema of a radiating multi-input system with a radiator that has a distributed nonlinear surface impedance; obtaining the nonlinear integral equations (NIE) related to the current density for radiators with distributed nonlinearity, excited by an arbitrary field distribution for solving the general analysis problem; obtaining a ratio for calculating focused electromagnetic fields (EMF) created by multi-input radiating structures with nonlinear characteristics in the Fresnel zone. The methods used in the paper are mathematical methods of electrodynamics and antennas theory with nonlinear elements (ANE), theory of microwave circuits, and multipoles. The following results were obtained. An electrodynamics approach is proposed to analyze the entire set of nonlinear effects arising in transmitting multi-input radiating structures with nonlinear characteristics. It allows considering the mutual influence of the transmitting and receiving antennas with nonlinear characteristics in the system itself and the electrodynamics interaction of the transmitting antenna with nonlinear characteristics with RES for other purposes. Component equations (NIE) of multi-input radiating structures that establish the relationship of amplitude-phase distribution at the inputs of radiators with distributed nonlinearity and amplitude-phase distribution on their surfaces are obtained. A mathematical model of multi-input radiator structures with nonlinear characteristics in the Fresnel zone for analysis purposes has been produced. Conclusions. The scientific novelty of the obtained results is as follows: a generalized theory of transmitting antennas of arbitrary configuration with nonlinear characteristics in the Fresnel zone, which makes it possible to analyze the characteristics of these antennas considering the positive and negative (beneficial and adverse) nonlinear effects that arise in them.

scholarly journals Economic-Mathematical Model and Mathematical Methods for Substantiating the Choice of the Company Innovation Strategy

2016 ◽  
Vol 9 (27) ◽  
Author(s):  
Aleksandr Mikhaylovich Batkovskiy ◽  
Pavel Andreevich Kalachikhin ◽  
Elena Georgievna Semenova ◽  
Yury Filippovich Telnov ◽  
Alena Vladimirovna Fomina
Keyword(s):  
Mathematical Model ◽  
Innovation Strategy ◽  
Mathematical Methods

scholarly journals Mathematical modeling and algorithm for calculation of thermocatalytic process of producing nanomaterial

2021 ◽  
Vol 23 (3) ◽  
pp. 1590
Author(s):  
Bakhtiyar Ismailov ◽  
Zhanat Umarova ◽  
Khairulla Ismailov ◽  
Aibarsha Dosmakanbetova ◽  
Saule Meldebekova
Keyword(s):  
Mathematical Model ◽  
Differential Equations ◽  
Solid Phase ◽  
Nonlinear Effects ◽  
Operating Characteristics ◽  
Laplace Transform Method ◽  
Transform Method ◽  
Wide Range ◽  
The Laplace Transform ◽  
Complex Mathematical Model

<p>At present, when constructing a mathematical description of the pyrolysis reactor, partial differential equations for the components of the gas phase and the catalyst phase are used. In the well-known works on modeling pyrolysis, the obtained models are applicable only for a narrow range of changes in the process parameters, the geometric dimensions are considered constant. The article poses the task of creating a complex mathematical model with additional terms, taking into account nonlinear effects, where the geometric dimensions of the apparatus and operating characteristics vary over a wide range. An analytical method has been developed for the implementation of a mathematical model of catalytic pyrolysis of methane for the production of nanomaterials in a continuous mode. The differential equation for gaseous components with initial and boundary conditions of the third type is reduced to a dimensionless form with a small value of the peclet criterion with a form factor. It is shown that the laplace transform method is mainly suitable for this case, which is applicable both for differential equations for solid-phase components and calculation in a periodic mode. The adequacy of the model results with the known experimental data is checked.</p>

scholarly journals Обеспечение электромагнитной совместимости систем интеллектуального управления при появлении помех в судовых кабельных трассах

2020 ◽  
Author(s):  
A.M. Agafonov ◽  
A.A. Worshevsky ◽  
P.A. Vorshevskii ◽  
E.S. Grishakov ◽  
A.S. Kornev
Keyword(s):  
Electromagnetic Interference ◽  
Electromagnetic Compatibility ◽  
Mutual Influence ◽  
Electromagnetic Coupling ◽  
Systems Design ◽  
Power Input ◽  
Travelling Wave ◽  
Normal Function ◽  
Input Output ◽  
Digital Technique

Системы интеллектуального управления базируются на использовании цифровой техники и по своему принципу действия восприимчивы к внешним помехам. Изменения напряжения и тока в кабелях, электромагнитные поля могут привести к появлению в цепях передачи информации и питания систем напряжений, похожих на полезные сигналы, что приведет к сбоям в работе систем. Технология электромагнитной совместимости (ЭМС) призвана устранить взаимные влияния оборудования и обеспечить его нормальную работу в условиях действия помех. Кабельные трассы являются особенно значимым фактором для обеспечения ЭМС на судах. Помехи распространяются в кабелям от источников к чувствительному электронному оборудованию (ЭО). Метод распространяющихся волн дает возможность рассчитать изменения помех при распространении по кабелям. Силовые и информационные кабели могут прокладываться в одной трассе, что приводит к их электромагнитной связи. Рассмотренные модели оценивают наведенные напряжения в информационных кабелях при появлении помех в силовых кабелях. Параметры электромагнитной связи кабелей могут быть определены расчетным путем и экспериментально на основе предлагаемой методики. Приведенные рекомендации по снижение уровня излучаемых помех от кабельных трасс, снижению наведенных напряжений и выполнению экранирования призваны помочь разработчикам ЭО и систем в обеспечении ЭМС.Intellectual control systems are based on digital technique. Digital electronic equipment (EE) is the receptor of electromagnetic interference due to its function principle. EE malfunction can be caused by induced voltages in input/output and power supply circuits. Voltage and current changes in cables leads to electromagnetic noise and induced voltages. Protection technique for power, input/output, case and grounding ports can be used in equipment and ship systems design. Electromagnetic compatibility technique must eliminate mutual influence of EE and give normal function of EE in real electromagnetic environment. Cable run is important factor for EMC obtaining in ships. Noise voltage propagates in cable from noise source to sensitive EE. Voltage parameters can be calculated with travelling wave technique. There are power and information cables in shipboard cable run. Electromagnetic coupling of cables leads to voltages in one cable induced by voltages and current in other cable. Coupling models give possibility to calculate induced voltages. Parameters of coupling can be determined with calculation on the base of detailed information about cable run or with proposed experiment procedure. Proposed recommendations about cable emission decreasing, cables decoupling and shielding can be useful for EMC obtaining.

scholarly journals ANALYSIS DEVELOPMENT OF AGRICULTURAL ENTERPRISES OF ECONOMIC-MATHEMATICAL METHODS USING

2021 ◽  
Author(s):  
Volodymyr Ulanchuk ◽  
Olena Zharun
Keyword(s):  
Mathematical Model ◽  
Development Strategy ◽  
Forage Production ◽  
Mathematical Methods ◽  
Cattle Breeding ◽  
Agricultural Enterprises ◽  
Sectoral Structure ◽  
Production Type ◽  
Regional Development Strategy ◽  
Different Types

The article deals with the problems of the regional development strategy, which primarily should be aimed at increasing the soil fertility in Ukraine. Suggested concept of innovation-investment development of agriculture, which is based on the objective necessity of providing agricultural enterprises in future with investments taking into account the state of their development, the most complete use of internal opportunities and adaptation to changes in the external environment. The economic-mathematical model for setting the prospects of agricultural production development has been developed. To substantiate the development of agricultural enterprises of different types of production prospects, the task matrix includes data on production and financial activities which was collected on the basis of typical agricultural enterprises. These enterprises data was determined on the basis of processing of statistical information on agrarian formations of a certain region. The proposed economic-mathematical model of the problem is designed in such way that it is possible to introduce other variants for the determined situations, by making minor changes in the limitations of its matrix. It gives opportunities to set the need for investments for the goal achievement with the maximum predicted profit by enterprises of each separate production type and in the whole region of enterprises which are engaged in the production of agricultural products. The solution of the problem by this model will enable to determine in each production type of agricultural enterprises such a sectoral structure of production, which gives the opportunity to obtain maximum profits and the minimum terms of return on investment. Developed activities at the stage of practical realization and commercialization of innovations allow increasing income of the agricultural enterprises from the cattle breeding and plant growing sectors, to organize their own production of the required amount of cultures to ensure optimum forage production beef cattle and dairy direction, to preserve quality characteristics of cultivated of soils.

scholarly journals Research of Polymetallic Sulfide Industrial Waste Nitric Acid Treatment

2017 ◽  
Vol 2 (2) ◽  
pp. 174
Author(s):  
Rogozhnikov D.A. ◽  
Dizer O.A. ◽  
Shoppert A.A.
Keyword(s):  
Nitric Acid ◽  
Industrial Waste ◽  
Mutual Influence ◽  
Acid Leaching ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Mathematical Methods ◽  
X Ray ◽  
Nitric Acid Leaching ◽  
Kinetic Features

<p>Thermodynamic and kinetic features studies of polymetallic sulfide industrial waste nitric acid leaching were carried out. Elemental and phase composition of investigated raw material were studied with X-ray diffraction and electron microscopy methods. Calculations of the Gibbs energy change for the likely reactions of sulfide minerals with nitric acid were performed. In order to determine the most probable conditions of the sulfide industrial waste leaching in nitric acid, as well as the mutual influence of the produced pulp components on the performance of the process, the kinetics evaluation of multicomponent sulfide industrial waste in a nitric medium was studied using mathematical methods.</p>

scholarly journals Inside–Out Method for Simulating a Reactive Distillation Process

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 604 ◽  
Author(s):  
Liang Wang ◽  
Xiaoyan Sun ◽  
Li Xia ◽  
Jianping Wang ◽  
Shuguang Xiang
Keyword(s):  
Mathematical Model ◽  
Design Research ◽  
Reactive Distillation ◽  
Mutual Influence ◽  
Molar Fraction ◽  
Estimation Method ◽  
Distillation Process ◽  
K Value ◽  
Calculation Process ◽  
Inside Out

Reactive distillation is a technical procedure that promotes material strengthening and its simulation plays an important role in the design, research, and optimization of reactive distillation. The solution to the equilibrium mathematical model of the reactive distillation process involves the calculation of a set of nonlinear equations. In view of the mutual influence between reaction and distillation, the nonlinear enhancement of the mathematical model and the iterative calculation process are prone to fluctuations. In this study, an improved Inside–Out method was proposed to solve the reaction distillation process. The improved Inside–Out methods mainly involved—(1) the derivation of a new calculation method for the K value of the approximate thermodynamic model from the molar fraction summation equation and simplifying the calculation process of the K value, as a result; and (2) proposal for an initial value estimation method suitable for the reactive distillation process. The algorithm was divided into two loop iterations—the outer loop updated the relevant parameters and the inside loop solved the equations, by taking the isopropyl acetate reactive distillation column as an example for verifying the improved algorithm. The simulation results presented a great agreement with the reference, and only the relative deviation of the reboiler heat duty reached 2.57%. The results showed that the calculation results were accurate and reliable, and the convergence process was more stable.

Discrete Preisach Model of a Shape Memory Alloy Actuator

2016 ◽  
Vol 248 ◽  
pp. 227-234
Author(s):  
Waldemar Rączka ◽  
Jarosław Konieczny ◽  
Marek Sibielak ◽  
Janusz Kowal
Keyword(s):  
Mathematical Model ◽  
Shape Memory Alloy ◽  
Parameter Identification ◽  
Shape Memory ◽  
Preisach Model ◽  
Discrete Form ◽  
Nonlinear Characteristics ◽  
Shape Memory Alloy Actuator ◽  
Sma Actuator ◽  
Identification Model

Shape Memory Alloy is a material used to designing actuators. These actuators have many advantages. They are light, strong and silent. They are building in laboratory and tested because beside advantages they have disadvantages too. SMA actuators have nonlinear characteristics with hysteresis loop.In the first part of the paper Shape Memory Alloys are shortly described. Next mathematical model was formulated. In the paper the Preisach model was developed. Discrete form of the model was considered and implemented. After parameter identification model was implemented in LabView. Tests of the model were conducted and results were worked. Obtained characteristics of the SMA actuator are shown in the paper. At the end of the paper the conclusions were formulated.

scholarly journals Optimization of Wireless Communication Coverage in Underground Tunnels Based on Zone Division

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Yu Huo ◽  
Qingsong Hu ◽  
Yanjing Sun ◽  
Xiwang Guo ◽  
Liang Qi ◽  
...  
Keyword(s):  
Wireless Communication ◽  
Fresnel Zone ◽  
Path Loss ◽  
Wireless Systems ◽  
Real Data ◽  
Communication Signal ◽  
Transmitting Antenna ◽  
Antenna Polarization ◽  
Zone Division ◽  
Multimodal Method

In order to reduce the path loss of the wireless communication signal in the underground tunnel, a scheme for configuring the antenna polarization of wireless systems based on a zone-division method is proposed. A multimodal method is used to estimate the effect of antenna polarization on the wireless propagation. When the optimal polarization of the antenna leading to low path loss is different in the zones near and far from the transmitting antenna, a dividing point is used to separate the zones. Experiments are conducted in an underground mine. It shows that the results by the multimodal method are consistent with the real data. Compared with the existing coverage schemes, the proposed scheme can obtain better coverage. Meanwhile, zone division has an important influence on the optimized performance of the wireless coverage. The zones divided based on Fresnel zone clearance and system identification are too small or too large, which result in incorrect polarization switching and high path loss.

Longitudinal Instability in Braked Landing Gear

1981 ◽  
Vol 103 (3) ◽  
pp. 259-265 ◽  
Author(s):  
R. R. Allen ◽  
R. C. O’Massey
Keyword(s):  
Mathematical Model ◽  
Steady State ◽  
Analytical Methods ◽  
Design Guidelines ◽  
Landing Gear ◽  
Nonlinear Mathematical Model ◽  
Nonlinear Characteristics ◽  
Aircraft Landing ◽  
Design Variables ◽  
Aircraft Landing Gear

An instability in the form of a self-excited, bounded longitudinal oscillation may occur in aircraft landing gear when one or more wheels lock due to excessive braking. The instability usually appears at ground speeds below 40 knots (20 m/s) and results from interaction between structural elasticity and the nonlinear characteristics of tire-runway friction. A nonlinear mathematical model is developed to study the dynamics of this divergence in a braked, dual tire landing gear. Analytical methods are presented to determine critical ground speeds in terms of runway friction characteristics and to predict the amplitude of steady-state oscillations. The effect of design variables on longitudinal stability is evaluated and design guidelines are presented which insure reduction of the severity of this divergent dynamic behavior.

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