scholarly journals Electromagnetic Simulation of New Tunable Guide Polarizers with Diaphragms and Pins

2021 ◽  
Vol 10 (3) ◽  
pp. 24-30
Author(s):  
S. Piltyay ◽  
A. Bulashenko ◽  
V. Shuliak ◽  
O. Bulashenko

In this article we present the results of mathematical simulation, development and optimization of a waveguide polarizer with a diaphragm and pins. A mathematical model was developed using the proposed approach on the example of a waveguide polarizer with one diaphragm and two pins. The diaphragm and pins were modeled as inductive or capacitive elements for two types of linear polarization of the fundamental modes. The applied model uses a wave scattering matrix. The total matrix of a polarizer was obtained using wave matrices of transmission of individual elements of the device structure. Using the elements of the common S-parameters the electromagnetic characteristics of the device, which is considered, were obtained. To check the performance of the developed mathematical model, it was simulated in a software using the finite element technique in the frequency domain. The designed structure of the polarizer is adjustable due to mechanical change in the length of the pins. The developed waveguide polarizer with one diaphragm and two pins provides a reflection coefficient of less than 0.36 and a transmission coefficient of more than 0.93 for two types of polarizations. Therefore, a new theoretical method was developed in the article for analysis of scattering matrix elements of a waveguide polarizer with diaphragms and pins. It can also be used for the development of new tunable waveguide polarizers, filters and other components with diaphragms and pins.

1994 ◽  
Vol 59 (5) ◽  
pp. 1066-1076 ◽  
Author(s):  
Šárka Klementová ◽  
Dana M. Wagnerová

The influence of ferric ions on photoinitiated reaction of dioxygen with two carbon organic acids, aldehydes and alcohols related to natural waters was demonstrated. Photocatalytic effect of ferric ions, i.e. photochemical reduction of Fe(III) as the catalyst generating step, has been found to be the common principal of these reactions. The overall quantum yields of the reactions are in the range from 0.3 to 1.2. A mathematical model designed for the mechanism of cyclic generation of catalyst in the singlet substrate oxidation by O2 was applied to the system glyoxalic acid + Fe(III); a fair agreement between the simulated and experimental kinetic curves was obtained. The experimental rate constant is 4.4 .10-4 s -1.


Author(s):  
M. A. Khanday ◽  
Fida Hussain ◽  
Khalid Nazir

The development of cold injury takes place in the human subjects by means of crystallization of tissues in the exposed regions at severe cold temperatures. The process together with the evaluation of the passage of fluid discharge from the necrotic regions with respect to various degrees of frostbites has been carried out by using variational finite element technique. The model is based on the Pennes' bio-heat equation and mass diffusion equations together with suitable initial and boundary conditions. The results are analyzed in relation with atmospheric temperatures and other parameters of the tissue medium.


Mathematics ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 244 ◽  
Author(s):  
Vildan Yazıcı ◽  
Zahir Muradoğlu

This study examined the deformation problem of a plate system (formed side-by-side) composed of multi-structure plates. It obtained numerical approaches of the transmission conditions on the common border of plates that composed the system. Numerical examples were solved in different boundary and transmission conditions.


2007 ◽  
Vol 07 (01) ◽  
pp. 75-87 ◽  
Author(s):  
MING A. TAN ◽  
FRANZ K. FUSS ◽  
GÜNTHER NIEGL

A mathematical model of the A2 pulley system will enable us to have a better understanding of the mechanics of the pulley-tendon system and provide us with insights of the pulley rupture mechanism. The A2 pulley was modeled based on parallel pulley fibers attached to a phalanx with a tendon passing them. Mechanical properties of the pulleys such as stiffness, strength and friction were included in the model. A convergence test was done to ensure the accuracy of the test. The model managed to show high loads on flexed finger may lead to pulley ruptures. Further studies on the rupture mechanism showed that pulley ruptures are self-propagating when a constant force is applied and the rate of rupture increases, as fewer intact fibers are present to support the load. The initial rate of propagation is much slower and this accelerates as more fibers are ruptured. This explains the common occurrence of partial pulley ruptures.


2012 ◽  
Vol 155-156 ◽  
pp. 726-730
Author(s):  
Zhong Hua Li ◽  
Qian Tang ◽  
Di Yan ◽  
Jie Wu

The common methods of cam induction hardening are discussed at present. By analyzing the basic motion law of conjugate cam, a new induction hardening mechanism is designed. The motion controlling mathematical model is built on the basis of the kinematic relationship of the transmission of the induction hardening mechanism. Through the mathematical model calculation, we can get angular velocity of the workbench, then realize that single axis on NC machine controls the inductor to make isometric uniform motion relative to the cam surface, so that the cam hardening depth distribution is uniform.


2020 ◽  
pp. 32-42
Author(s):  
G A Guryanov ◽  
B M Abdeev

A grinding process using a free impact breakage mechanism is used in industries. In order to make calculations, predict grinding results, and evaluate mills functioning, it is necessary to assess the parameters of the grinding process and interrelations between the process parameters, mills parameters and materials properties, i.e. it is necessary to use an adequate mechanical-mathematical model of the process. However it is difficult to model due to some phenomena occurring in this process. Nowadays, various researchers have established the basis for the structure of the grinding process, but the application of the existing hypotheses and methods to evaluate the grinding process is quite difficult. This paper solves the problem of a spherical shape particle impacting an absolutely rigid half-space. It proposes a refined mechanical and mathematical model describing the process of destruction of the particle using the free direct impact breakage mechanism on an absolutely rigid, stationary, and flat surface. By using the Hertz-Staerman's classical analytical dependencies on the force contact interaction of the spherical bodies and the technical theory of the longitudinal waves’ propagation in the elastic continuous medium, we obtained a new refined solution of the applied dynamic problem related to a direct impact of a ball simulating a particle of a feeding material (an absolutely rigid surface simulating the working body of the mill) taking into account local physically linear deformations, the time parameter and radial particle size. The improved theoretical model of the spherical particle destruction was brought to applicable analytical calculations, tested and illustrated by a numerical example. It made it possible to describe the fracture of the material particles, predict the result and calculate the grinding process depending on its parameters providing the required quality of grinding by regulating and selecting characteristics, designing and selecting the grinding equipment, and modeling the grinding process using the free impact breakage mechanism.


2021 ◽  
Author(s):  
Melvin Ikwubuo ◽  
Jinkwan Song ◽  
Jong Guen Lee

Abstract Combustion dynamics has been a significant problem for a lean, premixed, prevaporized (LPP) combustor. Understanding the acoustic characteristics of combustor components is essential to modeling thermoacoustic behavior in a gas turbine combustion system. Acoustic characteristics such as impedance and scattering matrix elements are experimentally determined for different-shape orifices with an emphasis on the effect of the flow field on them. These orifices are used to represent premixed swirl cups in LP combustors. The validity and limitation of two different methodologies are evaluated by comparing measured results with those of others. Consistent with analytical predictions, the measured resistance through an orifice increases as the bias flow increases. Different types of orifices considered in this study behave similarly to a thin orifice at high bias flow even though the discharge coefficients vary as much as 30% between them. The conventional method produces impedance values independent of waves reflected from the end boundary condition only when the scattering elements at the orifice downstream are roughly equal to those upstream of the orifice. However, the scattering matrix method produces impedance values that are not affected by the source or reflected waves at the system’s boundary. The scattering matrix measurements show that the reflection and transmission elements increases and decreases, respectively, as the bias flow through an orifice increases.


2018 ◽  
Vol 18 ◽  
pp. 49-54
Author(s):  
Naceur Amel ◽  
Adjadj Fouzia

In this work we discussed the modeling of the demixing curve in the liquid state in the Lead – Zinc binary system. We are interested to recalculate the free energies relating on Pb-Zn alloys for several temperatures based on the thermodynamic data collected in the bibliography. This calculation allows us to trace the curve of phase separation from a program after obtaining the mole fractions corresponding to the common tangent to the curve of the free energy with two minima at different temperatures. To do this, we used the Matlab 7.1 as the programming language and the Redlich-Kister polynomial as a mathematical model of development. The results obtained are very satisfactory by comparing them with those of the bibliography.


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