Model of radar station functioning in energy potential instability conditions

2021 ◽  
Author(s):  
B.B. Pankov ◽  
E.E. Smirnov ◽  
S.G. Vorona
Keyword(s):  
Electromagnetic Waves ◽  
Operating Conditions ◽  
Normal Operation ◽  
Actual State ◽  
Energy Potential ◽  
Precision Data ◽  
Radar Station ◽  
False Target ◽  
Space Objects ◽  
Decimeter Range

The energy potential of the radar is evaluated at the stage of testing when accompanied by reference spacecraft-calibration spheres. At the same time, special attention is paid to the readiness and serviceability of the radar equipment for conducting measurements and providing tests with high-precision data on the position in space and the effective scattering area (ESA) of the reference spacecraft. However, during the normal operation of the radar, it is often not possible to provide such conditions – the state of the radar equipment during measurements is constantly changing, and the limited number of calibration spheres in orbit does not allow measurements to be carried out with sufficient frequency. At the same time, in the radar field of view, there are constantly associated spacecraft for various purposes, measurements of the trajectory parameters of which can be used to assess the energy potential of the radar in real time. When making such measurements, it is necessary to take into account the actual state of the radar equipment and the fluctuations of the signal reflected from the spacecraft of complex shape. The presented model describes the factors that affect the instability of the energy potential during the operation of the radar in real operating conditions when accompanied by associated spacecraft, and allows us to identify the most significant of them. Currently, there are radar models that take into account the features of tracking space objects when changing the conditions for the propagation of electromagnetic waves in space, maneuvering targets, when observing targets against the background of interference, and others. At the same time, the combination of changes in the energy parameters of the radar and the reflected signal in these models was not fully considered. The need to create a model for the operation of a radar station in conditions of instability of the energy potential is also due to the development of technologies for creating small-sized spacecraft, the main distinguishing feature of which is the low radar visibility for stations in the decimeter range. As the ESA decreases, the power of the signal received by the antenna decreases, which increases the relative measurement error and increases the probability of a false target miss. Small-sized spacecraft are understood to be spacecraft with linear dimensions of the order of 0,1x0,1x0,1 m. The ESA of such objects varies in the range from a few hundredths to units of square meter σэф = (0,01…4) m2.

The role of physical factors in the complex therapy of patients with rheumatoid arthritis

1985 ◽  
Vol 66 (4) ◽  
pp. 318-318
Author(s):  
L. V. Chernetsova ◽  
A. G. Ibragimova
Keyword(s):  
Rheumatoid Arthritis ◽  
Comparative Analysis ◽  
Drug Therapy ◽  
Electromagnetic Waves ◽  
Physical Factors ◽  
Complex Therapy ◽  
Decimeter Range

The comparative analysis of treatment of 76 patients with rheumatoid arthritis using electromagnetic waves of the decimeter range and lithium electrophoresis, depending on the activity of the process and the type of drug therapy.

Overview of methods for controlling the parameters of the tracking mode of a multifunctional radar station

2021 ◽  
Vol 8 ◽  
pp. 122-135
Author(s):  
P.V. Pustozerov ◽  
A.L. Priorov
Keyword(s):  
Quality Criteria ◽  
Subject Area ◽  
Operating Conditions ◽  
Practical Significance ◽  
Radar Station ◽  
Tracking Mode ◽  
Probing Signal ◽  
Scope Of Application ◽  
Mathematical Equations ◽  
Control Criteria

Problem statement. With the development of devices for electronic control of the spatial position of the antenna radiation pattern, it became possible to control the time and duration of probing the radar station of various angular directions. There are many works based on the use of this principle to solve various radar tasks, in particular, to implement the target tracking mode. However, there is no general overview of the developed methods for controlling the parameters of the maintenance mode, the conditions and restrictions introduced in them, control and optimization criteria, as well as the scope of application. Goal. Analysis of the main methods of controlling the parameters of the tracking mode of a multifunctional radar station, including the control criteria used. Results. The analysis of the main methods of controlling the time of probing a target by a radar station, the duration of its probing pulses and signal is carried out. All methods are combined into several groups, the conditions and restrictions introduced during their development are defined. The quality criteria on the basis of which they are synthesized are analyzed. Practical approaches to calculating the parameters of the tracking mode of modern multifunctional radar stations are considered. The directions of further research of the subject area under consideration are formulated. Practical significance. The scientific and methodological apparatus used in calculating the parameters of the tracking mode of multifunctional radar stations is determined. Mathematical equations are given for calculating the duration of the probing signal and the time of probing the target. A set of parameters that must be taken into account when synthesizing control methods is determined. The applicability of the methods in various operating conditions of the radar station is evaluated.

scholarly journals Full-Scale Wind Turbine Vibration Signature Analysis

Machines ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 63 ◽  
Author(s):  
Xavier Escaler ◽  
Toufik Mebarki
Keyword(s):  
Wind Farm ◽  
Power Spectra ◽  
Operating Conditions ◽  
Drive Train ◽  
Normal Operation ◽  
Common Source ◽  
Variable Speed ◽  
Data Set ◽  
Vibration Signature ◽  
Power Curves

A sample of healthy wind turbines from the same wind farm with identical sizes and designs was investigated to determine the average vibrational signatures of the drive train components during normal operation. The units were variable-speed machines with three blades. The rotor was supported by two bearings, and the drive train connected to an intermediate three-stage planetary/helical gearbox. The nominal 2 MW output power was regulated using blade pitch adjustment. Vibrations were measured in exactly the same positions using the same type of sensors over a six-month period covering the entire range of operating conditions. The data set was preliminary validated to remove outliers based on the theoretical power curves. The most relevant frequency peaks in the rotor, gearbox, and generator vibrations were detected and identified based on averaged power spectra. The amplitudes of the peaks induced by a common source of excitation were compared in different measurement positions. A wind speed dependency of broadband vibration amplitudes was also observed. Finally, a fault detection case is presented showing the change of vibration signature induced by a damage in the gearbox.

scholarly journals Technical requirements for translucent structures of schools and kindergartens

2019 ◽  
Vol 91 ◽  
pp. 05019
Author(s):  
Aleksandr Konstantinov ◽  
Elena Romanerikova ◽  
Margarita Borisova
Keyword(s):  
Operating Conditions ◽  
Normal Operation ◽  
Future Research ◽  
Natural Lighting ◽  
Technical Requirements ◽  
Standard Construction ◽  
Temperature And Humidity ◽  
Typical Composition ◽  
Room Lighting ◽  
Construction Practice

The article presents some features of the translucent structures design of schools and kindergartens. The analysis of technical requirements for translucent structures of schools and kindergartens was represented. Based on a review of the typical composition of the premises of schools and kindergartens, it was found that different technical requirements should be established for translucent structures installed in rooms of various functional purposes and operating conditions. It was determined that the existing construction practice doesn’t take into account the differentiation of requirements for translucent structures of various premises of schools and kindergartens, and their design, as a rule, is taken to be the same for the entire construction objects. In future, it leads to disruption of the normal operation of the facility (especially in terms of ensuring normal temperature and humidity conditions and natural lighting of the premises). The features of the replacement of translucent structures in reconstructed schools and kindergartens were considered. It has been revealed that the use of modern types of translucent structures of standard construction (first of all, PVC window units) in the reconstruction leads to a significant decrease in the indicators of natural room lighting. Ways to solve this problem were given. Moreover, perspective directions for future research of the issue under consideration were considered.

Numerical simulation of ship propulsion transients and full-scale validation

2003 ◽  
Vol 217 (1) ◽  
pp. 41-52 ◽  
Author(s):  
U Campora ◽  
M Figari
Keyword(s):  
Full Scale ◽  
Operating Conditions ◽  
Dynamics Simulation ◽  
Normal Operation ◽  
System Response ◽  
Prime Mover ◽  
Software Environment ◽  
Simulation Code ◽  
Ship Propulsion ◽  
Wide Range

The paper describes a mathematical model for the dynamics simulation of ship propulsion systems. The model, developed in a MATLAB-SIMULINK software environment, is structured in modular form; the various elements of the system are described as individuals blocks (hull, prime mover, gear, waterjet, etc.) and linked together to take their interactions into account. In this way it is possible to characterize the dynamic behaviour of both the single component and the whole propulsion plant. The model may be used to analyse the system response at off-design and transient conditions. In particular, the developed computer simulation code may be considered as a useful tool to facilitate the correct matching of the prime mover (diesel or gas turbine) to the propulsor (waterjet or propeller) in a wide range of operating conditions. The paper shows the application of the methodology to a cruise ferry used to validate the model results through a full-scale test campaign conducted by the authors during normal operation of the ship.

scholarly journals Features of use direct and external modulation in fiber optical simulators of a false target for testing radar station

2018 ◽  
Vol 1038 ◽  
pp. 012035 ◽  
Author(s):  
M.Yu. Tarasenko ◽  
V.A. Lenets ◽  
K.Yu. Malanin ◽  
N.V. Akulich ◽  
V.V. Davydov
Keyword(s):  
Radar Station ◽  
External Modulation ◽  
False Target ◽  
Fiber Optical

The Effect of Operational Parameters on Vibration Signals of Wind Turbine Gearboxes

2019 ◽  
Author(s):  
Sofia Koukoura ◽  
Eric Bechhoefer ◽  
James Carroll ◽  
Alasdair McDonald
Keyword(s):  
Wind Turbine ◽  
Operating Conditions ◽  
Operating Costs ◽  
Normal Operation ◽  
Operational Parameters ◽  
Wind Turbine Gearbox ◽  
Vibration Signals ◽  
Gearbox Vibration ◽  
Maintenance Decisions ◽  
Yaw Angle

Abstract Vibration signals are widely used in wind turbine drivetrain condition monitoring with the aim of fault detection, optimization of maintenance actions and therefore reduction of operating costs. Signals are most commonly sampled by accelerometers at high frequency for a few seconds. The behavior of these signals varies significantly, even within the same turbine and depends on different parameters. The aim of this paper is to explore the effect of operational and environmental conditions on the vibration signals of wind turbine gearboxes. Parameters such as speed, power and yaw angle are taken into account and the change in vibration signals is examined. The study includes examples from real wind turbines of both normal operation and operation with known gearbox faults. The effects of varying operating conditions are removed using kalman filtering as a state observer. The findings of this paper will aid in understanding wind turbine gearbox vibration signals, making more informed decisions in the presence of faults and improving maintenance decisions.

scholarly journals Complex Bogie Modeling Incorporating Advanced Friction Wedge Components

2009 ◽  
Author(s):  
Brian Sperry ◽  
Corina Sandu ◽  
Brent Ballew
Keyword(s):  
Dynamic Behavior ◽  
Degrees Of Freedom ◽  
Model Simulation ◽  
Surface Friction ◽  
Rigid Bodies ◽  
Operating Conditions ◽  
Normal Operation ◽  
Contact Points ◽  
Modeling Software ◽  
Simulation Results

This research focuses on the dynamic behavior of the three-piece bogie that supports the freight train car bodies. While the system is relatively simple, in that there are very few parts involved, the behavior of the bogie is somewhat more complex. Our research focuses primarily on the behavior of the friction wedges under different operating conditions that are seen under normal operation. The Railway Technologies Laboratory (RTL) at Virginia Tech has been developing a model to better capture the dynamic behavior of friction wedges using 3-D modeling software. In previous years, a quarter-truck model, and half-truck variably damped model have been developed using MathWorks MATLAB®. This year, research has focused on the development of a half-truck variably damped model with a new (curved surface) friction wedge, and a half-truck constantly damped model, both using the MATLAB® based software program. Currently a full-truck variably damped model has been created using LMS Virtual.Lab. This software allows for a model that is more easily created and modified, as well as allowing for a much shorter simulation time, which became a necessity as more contact points, and more complex inputs were needed to increase the accuracy of the simulation results. The new model consists of seven rigid bodies: the bolster, two sideframes, and four wedges. We have also implemented full spring nests on each sideframe, where in previous models equivalent spring forces were used. The model allows six degrees-of-freedom for the wedges and bolster: lateral, longitudinal, and vertical translations, as well as pitch, roll, and yaw. The sideframes are constrained to two degrees-of-freedom: vertical and longitudinal translations. The inputs to the model are vertical and longitudinal translations or forces on the sideframes, which can be set completely independent of each other. The model simulation results have been compared with results from NUCARS®, an industrially-used train modeling software developed by the Transportation Technology Center, Inc. (TTCI), a wholly owned subsidiary of the Association of American Railroads (AAR), for similar inputs, as well as experimental data from warping tests performed at TTCI.

An Extended Model of Light Railway System Used in Analysis of Normal Operation and Fault Conditions

2014 ◽  
Author(s):  
Sorin Deleanu ◽  
Keith Forman ◽  
David C. Carpenter ◽  
Calin Munteanu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Short Circuit ◽  
Operating Conditions ◽  
Normal Operation ◽  
Dc Power ◽  
Railway System ◽  
Analytical Approaches ◽  
Element Method

The paper provides a description of the analysis of a Light Railway System for two configurations: - Rails above the ground and catenary supply - Track in a tunnel and power rail supply. Finite Element Method (FEM) analysis is compared to classical analytical approaches by Carson, Pollaczek, Bickford and Tylavsky. Reviews of methods to determine self and mutual impedance for electrified railroads are provided. The solution of finite element method (FEM) applied for the determination of impedance for the two traction rail and catenary configuration, modeled and examined, consists of computational analysis based upon minimizing the energy of electromagnetic field. The analytic impedance models are built on Carson-Pollaczek–Bickford equations, adjusted by Tylavsky, for two situations: when the ground is perfectly insulated and when considering the earth return current. The railway track – catenary is integrated in a system containing the model for traction substation(s) with DC power output and moving vehicle with induction motors, controlled using voltage inverters with pulse width modulation. The light transit train, supplied with a rectified DC power, is subjected to a significant harmonic content, which may affect the signal and control circuits. It is then shown that the power and signaling characteristics of the modelled system can predict the magnitude of the perturbation current for different frequencies, in normal operating conditions and in presence of faults as well. In many of the light transportation systems, from all types of faults, the DC short-circuit at the output of the power rectifiers used for energizing the power rail and/or catenary presents a special interest. This is because of two main reasons: the positions of the vehicle-loads are in continuous changing and, even if they operate from DC sources, the parent network is still of AC type. A key issue was the determination of the distributed parameters (resistances, inductances) of the running track and catenary, from experimental data and preliminary analytical and numerical calculations, followed by the analysis of their dependencies with the current magnitude and frequency response. A specific short-circuit study case is simulated when using a model of the traction system for the purpose of the DC fault current prediction. The paper concludes with a discussion of future developments and further work.

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