scholarly journals Automatic Measurement of Magnetron Rieke Diagrams

2019 ◽  
Author(s):  
Vladimir Bilik
Keyword(s):  
Reflection Coefficient ◽  
Anode Voltage ◽  
Block Diagram ◽  
Impedance Matching ◽  
Real Life ◽  
Automatic Measurement ◽  
Operating Conditions ◽  
Polar Diagram ◽  
Coupling Structure ◽  
Fully Automatic

A Rieke diagram [1] is a magnetron characteristic that visualizes the dependence of the generated frequency fg and the net delivered power PL on the load reflection coefficient GR. GR is defined in a specific magnetron-to-waveguide coupling structure called the standard or reference launcher (Fig. 1). The diagram is plotted as a family of isolines of constant fg and of constant PL in the polar diagram of GR. Rieke diagrams are essential in the design of applications without isolators, such as domestic or professional microwave ovens. Constructing Rieke diagrams is tedious, time-consuming and equipment-demanding [2], [3], preventing systematic studies of their dependence on operating conditions, such as anode voltage and its ripple, filament current, mounting repeatability, etc. We have devised a procedure, centering around a high-power automatic impedance matching device (autotuner), which enables fully automatic measurement and plotting of the stated dependences. A block diagram of the setup is shown in Fig. 1. The autotuner, when terminated in a match (waterload), can accomplish a task inverse to impedance matching: realizing any desired reflection coefficient GR. The measurement consists of stepping through a grid of n suitably chosen reflection coefficients GR = xR + jyR, covering a desired area of the polar diagram. Each GR is measured accurately by the autotuner, along with the corresponding fg and PL. Thus, raw data for constructing a Rieke diagram are obtained, the data consisting of a collection of n points {GR, fg, PL}i, i = 1…n, with GR, in general, irregularly scattered in the complex plane. A dedicated MATLAB routine then reads the data, sorts them out to create tabulated functions fg = f(xR, yR), PL = f(xR, yR), approximates these by a 2D spline, and uses the splines to plot smoothed isocontours for chosen constant values of fg and PL, completing thus the desired Rieke diagram construction. We will present details of this procedure as well as real-life examples. Fig. 1. Rieke diagram measurement setup. References Meredith, R. J., Engineers' Handbook of Industrial Microwave Heating, London: The IEE, 1998, 250–270. Takahashi, H., I. Namba, K. Akiyama, J. Microwave Power, 1979, 14, 261–267.Yixue, W., Z. Zhaotang, Proc. ICMMT'98, 1998, 795–798.

scholarly journals Quadrature method for broadband measurement of microwave path parameters

2021 ◽  
Vol 2094 (3) ◽  
pp. 032046
Author(s):  
Yu Gimpilevich ◽  
Yu Tyschuk
Keyword(s):  
Reflection Coefficient ◽  
Block Diagram ◽  
Power Level ◽  
Automatic Measurement ◽  
Measurement Procedure ◽  
System Of Nonlinear Equations ◽  
Complex Reflection Coefficient ◽  
Complex Reflection ◽  
Channel Parameters ◽  
Analytical Expressions

Abstract A mathematical model has been developed for the procedure for broadband automatic measurement of the complex reflection coefficient and power level in the microwave path based on the quadrature measurement method. Analytical expressions are obtained for the quadrature components at the outputs of a quadrature demodulator connected with a switch to two non-directional measuring probes for the case of an unmatched microwave path. A modified system of nonlinear equations with respect to measured values was formed and solved, which allows setting zero assumptions. A block diagram of a broadband device for built-in automatic control of microwave channel parameters has been developed, which implements the developed measurement procedure and the solution of a system of measurement equations to determine the current values of the power level factor, as well as the modulus and argument of the complex reflection coefficient.

scholarly journals Modeling of a Real-Life Industrial Reactor for Hydrogenation of Benzene Process

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 412
Author(s):  
Mirosław K. Szukiewicz ◽  
Krzysztof Kaczmarski
Keyword(s):  
Catalyst Activity ◽  
Real Life ◽  
Operating Conditions ◽  
Reactor Operation ◽  
Reactor Model ◽  
High Scale ◽  
Industrial Reactor ◽  
Knowledge Based ◽  
Operation Conditions ◽  
Insight Into

A dynamic model of the hydrogenation of benzene to cyclohexane reaction in a real-life industrial reactor is elaborated. Transformations of the model leading to satisfactory results are presented and discussed. Operating conditions accepted in the simulations are identical to those observed in the chemical plant. Under those conditions, some components of the reaction mixture vanish, and the diffusion coefficients of the components vary along the reactor (they are strongly concentration-dependent). We came up with a final reactor model predicting with reasonable accuracy the reaction mixture’s outlet composition and temperature profile throughout the process. Additionally, the model enables the anticipation of catalyst activity and the remaining deactivated catalyst lifetime. Conclusions concerning reactor operation conditions resulting from the simulations are presented as well. Since the model provides deep insight into the process of simulating, it allows us to make knowledge-based decisions. It should be pointed out that improvements in the process run, related to operating conditions, or catalyst application, or both on account of the high scale of the process and its expected growth, will remarkably influence both the profits and environmental protection.

Selectivity and in-band impedance enhancement of a compact slot antenna with defected ground structures

2019 ◽  
Vol 11 (10) ◽  
pp. 1010-1016
Author(s):  
Hailong Yang ◽  
Xiaoli Xi ◽  
Lili Wang ◽  
Yuchen Zhao ◽  
Xiaomin Shi
Keyword(s):  
Reflection Coefficient ◽  
Impedance Matching ◽  
Ultra Wideband ◽  
Band Edge ◽  
Slot Antenna ◽  
Defected Ground Structure ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Uwb Antennas ◽  
Low Pass

AbstractIn this study, a new ultra-wideband (UWB) band-edge selectivity antenna with a modified radiation slot using defected ground structure (DGS) is presented to obtain bandpass filtering reflection coefficient and gain performance. The well-designed DGS is designed on backside metallic of the substrate and can be seen as a low-pass filter that provides a good roll-off at a higher frequency. By connecting the DGS and the stepped slot and making them merge with each other, good cut-off property in the upper passband and better in-band impedance characteristics are obtained. Measured results show that the proposed design not only shows good band-edge selectivity in reflection coefficient and gain performance but also has a good impedance matching of −13.5 dB reflection coefficients and a good radiation efficiency of 90% in the operating frequencies. The measured bandwidth defined with the reflection coefficient less than −10 dB is from 3.1–11.2 GHz. Furthermore, the size of the filtering UWB antenna is 22 mm × 12 mm, which is smaller than many individual UWB antennas and UWB filters.

A Solution Framework for Response Surface-Based Multiple Quality Characteristics Optimization

2018 ◽  
Vol 25 (05) ◽  
pp. 1850025
Author(s):  
Sasadhar Bera ◽  
Indrajit Mukherjee
Keyword(s):  
Response Surface ◽  
Optimization Problems ◽  
Real Life ◽  
Quality Characteristics ◽  
Operating Conditions ◽  
Simultaneous Optimization ◽  
Trade Off ◽  
Multiple Quality Characteristics ◽  
Pin On Disc ◽  
Application Potential

A common problem generally encountered during manufacturing process improvement involves simultaneous optimization of multiple ‘quality characteristics’ or so-called ‘responses’ and determining the best process operating conditions. Such a problem is also referred to as ‘multiple response optimization (MRO) problem’. The presence of interaction between the responses calls for trade-off solution. The term ‘trade-off’ is an explicit compromised solution considering the bias and variability of the responses around the specified targets. The global exact solution in such types of nonlinear optimization problems is usually unknown, and various trade-off solution approaches (based on process response surface (RS) models or without using process RS models) had been proposed by researchers over the years. Considering the prevalent and preferred solution approaches, the scope of this paper is limited to RS-based solution approaches and similar closely related solution framework for MRO problems. This paper contributes by providing a detailed step-by-step RS-based MRO solution framework. The applicability and steps of the solution framework are also illustrated using a real life in-house pin-on-disc design of experiment study. A critical review on solution approaches with details on inherent characteristic features, assumptions, limitations, application potential in manufacturing and selection norms (indicative of the application potential) of suggested techniques/methods to be adopted for implementation of framework is also provided. To instigate research in this field, scopes for future work are also highlighted at the end.

Formation of a risk assessment model when selecting a foreign supplier under a foreign trade contract

2020 ◽  
Vol 26 (10) ◽  
pp. 82-87
Author(s):  
Lin Peng ◽  
Keyword(s):  
Supply Chain ◽  
Block Diagram ◽  
Operating Conditions ◽  
Assessment Model ◽  
Supply Chain Risk Management ◽  
Sources Of Information ◽  
Supply Chain Risk ◽  
Product Lines ◽  
Foreign Supplier ◽  
The Status

Many businesses that work with a large number of product lines face the problem of choosing a supplier of goods or services. The problem of finding suppliers is faced by most businesses that do business and are looking for new ways to optimize costs. Enterprises need to periodically search for suppliers, and this is much more difficult for them due to lack of experience, especially in relations with foreign suppliers. Procurement planning is carried out by selecting suppliers who must meet previously established criteria set by the company’s standards and legislation. The search and analysis of suppliers should be carried out systematically using all possible sources of information. At the present stage, conservative methods of searching, analyzing and selecting suppliers are being improved and supplemented with new forms and methods, but none of the existing methods of selecting a supplier properly takes into account the current operating conditions. Therefore, supply chain management is particularly relevant and requires improvement. The article suggests a model that allows identifying potentially unscrupulous suppliers even before the contract is executed in the supply chain and using management. The article presents a block diagram of the supply chain risk management model. The model specifies a key condition aimed at combining the work of all departments in order to increase the transparency of procedures. At the same time, the model will reduce the risks of the supply chain and improve the process of making logistics decisions within 3 main blocks. Information about the entire lifecycle of equipment, media, and items is stored in the supply chain information system, reflecting the status and attributes of all aspects and providing a variety of data support for decision - making

scholarly journals Bond-Graph model based stepper motor output characteristics simulation implemented in LabVIEW environment

2021 ◽  
Vol 7 (1.) ◽  
Author(s):  
Zsolt Molnár
Keyword(s):  
Block Diagram ◽  
Real Life ◽  
Graph Model ◽  
Bond Graph ◽  
Visual Programming ◽  
Stepper Motor ◽  
Intermediate Step ◽  
Virtual Device ◽  
Wide Range ◽  
Made In

In the industry, simulations are of great importance. They enable measurements to be made in different conditions about a virtual device, which are highly comparable to measurements made in a real life scenarios. Because of their wide range of usage in lower power drive systems, where precision and simplicity is a must, the subject of study is a permanent magnet stepper motor. For precise positioning purposes, it is essential to know the positioning behaviour of these devices. The model construction process involved an intermediate step, which consisted of creating the Bond-Graph of the motor based on pre-defined models available in the literature in this field. In the next step, the Bond-Graph model was converted to a block diagram of the motor. This permitted the direct implementation of the motor model in LabVIEW visual programming environment. The preliminary steps allows us to check and confirm the functionality and correctness of the model. This article covers in detail the model conversion and implementation steps of the simulation. At the end, the functionality of the simulation was tested.

scholarly journals Simulation Study of the Process of Friction in the Working Elements of a Car Braking System at Different Degrees of Wear

2018 ◽  
Vol 12 (3) ◽  
pp. 221-226 ◽  
Author(s):  
Andrzej Borawski
Keyword(s):  
Simulation Study ◽  
Friction Pair ◽  
Experimental Studies ◽  
Real Life ◽  
Operating Conditions ◽  
Heating Process ◽  
Passenger Cars ◽  
The Road ◽  
Emergency Braking ◽  
Braking System

Abstract Among the many elements of a modern vehicle, the braking system is definitely among the most important ones. Health, and, frequently, life, may rest upon the design and reliability of brakes. The most common friction pair used in passenger cars today is a disc which rotates with the road wheel and a cooperating pair of brake pads. The composite material of the pad results in changing tribological properties as the pad wears, which was demonstrated in experimental studies. The change is also facilitated by the harsh operating conditions of brakes (high and rapid temperature changes, water, etc.). This paper looks into how changing tribology reflects on the heating process of disc and pads during braking. And so a simulation study was conducted, as this method makes it possible to measure temperature in any given point and at any time, which is either impossible or extremely difficult in real life conditions. Finite element method analyses were performed for emergency braking events at various initial speeds of the vehicle reflecting the current road speed limits.

scholarly journals Design of Cavity-Backed Bow-Tie Antenna with Matching Layer for Human Body Application

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 4015 ◽  
Author(s):  
Jeong ◽  
Park ◽  
Lee
Keyword(s):  
Reflection Coefficient ◽  
Human Body ◽  
Electromagnetic Interference ◽  
Impedance Matching ◽  
Human Head ◽  
Impedance Match ◽  
Broadband Antenna ◽  
Matching Layer ◽  
Antenna Performance ◽  
Bow Tie

This paper presents the broadband antenna for the microwave radiometric sensing of internal body temperature. For broadband operation, the bow-tie antenna was designed and backed with a cylindrical cavity, which decreased environmental electromagnetic interference and also improved the directivity of the antenna. The broadband impedance-transforming balun in microstrip form was also designed to feed the bow-tie antenna, and was located inside the cavity. An impedance-matching dielectric layer (IMDL) was introduced on top of the bow-tie antenna, for impedance match with the human body with high permittivity. The fabricated antenna was measured in free space with the IMDL removed, showing an input reflection coefficient lower than −10 dB from 2.64 to > 3.60 GHz with antenna gain over 6.0 dBi and radiation efficiency over 74.7% from 2.7 to 3.5 GHz. The IMDL was re-installed on the cavity-backed bow-tie antenna to measure the antenna performance for the human head with relative permittivity of about 40. The measured reflection coefficient was as low as −28.9 dB at 2.95 GHz and lower than −10 dB from 2.65 to > 3.5 GHz. It was also shown that the designed antenna recovered a good impedance match by adjusting the permittivity and thickness of the IMDL for the different parts of the human body with different permittivities.

scholarly journals Physical features of reducing air pollution for the operating conditions of the drying drum of brick factories

2019 ◽  
Vol 135 ◽  
pp. 01034
Author(s):  
Vadim Bespalov ◽  
Gennadiy Turk ◽  
Oksana Gurova
Keyword(s):  
Air Pollution ◽  
Theoretical Basis ◽  
Block Diagram ◽  
Operating Conditions ◽  
Engineering Systems ◽  
Effective Implementation ◽  
Energy Concept ◽  
Physical Features ◽  
Relationship Of ◽  
The Relationship

The article is devoted to the study of the process of reducing air pollution in relation to the operating conditions of the drying drum of brick factories. The objectives of the work were to study and identify the physical characteristics of the process of reducing air pollution for the operating conditions of the drying drum of brick factories, for its subsequent effective implementation with the help of engineering systems. A block diagram is suggested of the physical model of the process of reducing air pollution for the considered production and technological conditions, revealing the relationship of a set of consistently and purposefully implemented stages of the cycle of dusting, using physical and energy concept as the theoretical basis. As a result of the study of the process of reducing air pollution, in relation to the operating conditions of the drying drum of brick factories operation, based on the analysis of possible solutions of the problem of dusting, physical features of the process of reducing air pollution for these production and technological conditions were identified for its subsequent effective implementation by means of engineering systems.

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