Eigenvalues of the axially symmetrical electromagnetic waves along an infinitely long and conductive circular cylinder in a homogeneous magnetoionic medium

1969 ◽  
Vol 47 (11) ◽  
pp. 1159-1166 ◽  
Author(s):  
K. Aoki
Keyword(s):  
Electromagnetic Field ◽  
Circular Cylinder ◽  
Electromagnetic Waves ◽  
Cyclotron Frequency ◽  
Numerical Results ◽  
Complex Conjugate ◽  
Field Frequency ◽  
Radial Propagation

This paper discusses eigenvalues of the electromagnetic field along an infinitely long and conductive circular cylinder imbedded in a magnetoionic medium under assumptions that the medium is lossless and the field frequency is not equal to the cyclotron frequency. It is shown that they are classified into two kinds: (i) k1 and k2 are pure imaginary and (ii) k22 = (complex conjugate of k12), where k1 and k2 are the radial propagation constants and that no eigenvalues exist in the region bounded by [Formula: see text] where ωp and ωc are the plasma and cyclotron frequencies normalized to the field frequency. Some numerical results in the case of (radius of the cylinder/wavelength) [Formula: see text] are also shown.

Dielectric properties of wheat flour mixed with oat meal

2013 ◽  
Vol 27 (2) ◽  
pp. 175-180 ◽  
Author(s):  
D. Łuczycka ◽  
A. Czubaszek ◽  
M. Fujarczuk ◽  
K. Pruski
Keyword(s):  
Electromagnetic Field ◽  
Dielectric Loss ◽  
Wheat Flour ◽  
Loss Factor ◽  
Ash Content ◽  
Dielectric Loss Factor ◽  
Field Frequency ◽  
Impedance Analyzer ◽  
Sedimentation Value

Abstract Possibilities of using electric methods for determining admixtures of oat meal to wheat flour, type 650 are presented. In wheat flour, oat meal and mixtures containing 10, 20 and 30% of the oat meal, moisture, protein, starch and ash content, sedimentation value, yield and softening of wet gluten were determined. In samples containing 0, 5, 10, 15, 20, 25, 30 and 100% of oat meal, the dielectric loss factor and conductivity were determined using an impedance analyzer for electromagnetic field frequency ranging from 0.1-20 kHz. It was found that the dielectric loss factor varied for tested material. The best distinguishing between tested mixtures was obtained at the measuring electromagnetic field frequency of 20 kHz. The loss factor was significantly correlated with the yield of wet gluten and the sedimentation value, parameters indicating the amount and quality of gluten proteins in flour.

scholarly journals The Computation of the Magnitude of the Far Field for an Eccentric Circular Cylinder

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Bülent Yılmaz
Keyword(s):  
Circular Cylinder ◽  
Plane Wave ◽  
Radiation Condition ◽  
Higher Order ◽  
Numerical Results ◽  
Surface Radiation ◽  
Far Field ◽  
Condition Method ◽  
Radiation Conditions

The specific case of scattering of a plane wave by a two-layered penetrable eccentric circular cylinder has been considered and it is about the validity of the on surface radiation condition method and its applications to the scattering of a plane wave by a two-layered penetrable eccentric circular cylinder. The transformation of the problem of scattering by the eccentric circular cylinder to the problem of scattering by the concentric circular cylinder by using higher order radiation conditions, is observed. Numerical results presented the magnitude of the far field.

Electromagnetic field generated by an off‐axis source in a cylindrically layered medium with an arbitrary number of horizontal discontinuities

Geophysics ◽  
1993 ◽  
Vol 58 (5) ◽  
pp. 616-625 ◽  
Author(s):  
Qing‐Huo Liu
Keyword(s):  
Arbitrary Number ◽  
Electromagnetic Waves ◽  
Layered Medium ◽  
Azimuthal Angle ◽  
Well Logging ◽  
Transverse Magnetic ◽  
Numerical Results ◽  
Optical Fiber Communications ◽  
Eccentricity Effect ◽  
Large Eccentricity

We investigate the propagation of electromagnetic waves in a cylindrically layered medium with an arbitrary number of horizontal discontinuities. The dielectric constant, conductivity, and magnetic permeability of the medium are functions of ρ and z only (i.e., independent of the azimuthal angle ϕ), but the field generated by an off‐axis source in this medium is in general a function of ρ, ϕ, and z. This two and a half‐dimensional (2.5-D) problem is often encountered in electromagnetic well logging, as well as in other areas such as optical fiber communications and integrated optics. We show that a coupling exists between the transverse electric (TE) and transverse magnetic (TM) components of the field even in the absence of the horizontal discontinuities, which makes it difficult to solve for the field. We apply an efficient numerical mode‐matching (NMM) algorithm to tackle this 2.5-D problem. This algorithm uses the local reflection and transmission operators developed in the recent work on the diffraction of nonaxisymmetric waves in a cylindrically layered medium with a single horizontal discontinuity. For several special geometries, we compare the numerical results from this NMM algorithm with analytical solutions as well as the earlier numerical results for axisymmetric cases, and found excellent agreement between them. As an application to the geophysical subsurface sensing, we solve several practical problems, and find that a large eccentricity effect can occur in realistic electromagnetic well logging. Moreover, this large eccentricity effect is strongly coupled with thin‐bed effect. Conventional log interpretation methods cannot adequately account for these effects. With the NMM algorithm developed here, all these different effects can be accounted for simultaneously and accurately.

Erratum: “Electromagnetic Waves near the Proton Cyclotron Frequency: STEREO Observations” (2014, ApJ, 786, 123)

2017 ◽  
Vol 847 (1) ◽  
pp. 82
Author(s):  
L. K. Jian ◽  
H. Y. Wei ◽  
C. T. Russell ◽  
J. G. Luhmann ◽  
B. Klecker ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Cyclotron Frequency ◽  
Proton Cyclotron

Propagation of ultrashort optical pulses in anisotropic optical media with carbon nanotubes

2021 ◽  
pp. 2150197
Author(s):  
N. N. Konobeeva ◽  
M. B. Belonenko
Keyword(s):  
Carbon Nanotubes ◽  
Electromagnetic Field ◽  
Vector Potential ◽  
Pulse Shape ◽  
Electromagnetic Waves ◽  
Optical Pulses ◽  
Effective Equation ◽  
Ultrashort Optical Pulses ◽  
Optical Media ◽  
Crystal Type

In this paper, we investigate the evolution of electromagnetic waves in a nonlinear anisotropic optical medium with carbon nanotubes (CNTs). Based on Maxwell’s equation, an effective equation is obtained for the vector potential of the electromagnetic field, which takes into account different values of the velocity and polarization with two directions. The dependence of the pulse shape on the crystal type, as well as the angle between the electric field and the CNTs axis is revealed.

scholarly journals Analysis on the Influence of Transmission Lines span on Passive Interference in Shortwave

2018 ◽  
Vol 64 ◽  
pp. 05004
Author(s):  
Ying Lu ◽  
Zhibin Zhao ◽  
Jian gong Zhang ◽  
Zheyuan Gan
Keyword(s):  
Electromagnetic Field ◽  
Transmission Line ◽  
Transmission Lines ◽  
Electromagnetic Scattering ◽  
Electromagnetic Waves ◽  
Short Wave ◽  
Critical Distance ◽  
Observation Point ◽  
Radio Station ◽  
Passive Interference

The passive interference of transmission lines to nearby radio stations may affect the effective reception and transmission of radio station signals. Therefore, the accurate calculation of the electromagnetic scattering of transmission lines under the condition of external electromagnetic waves is the basis for determining the reasonable avoidance spacing of the two. For passive stations operating in short-wave frequencies, passive interference is mainly generated by the tower, and span is one of the most significant factors affecting passive interference. This paper uses the method of moments to carry out the passive interference calculations under normal circumstances, expounds the method of calculating the electromagnetic field of transmission line at the same time. And elaborates the method for calculating the electromagnetic field of the transmission line, obtains the space electric field intensity of the transmission line at the same working frequency and space location of the plane wave. Applying the approximate formula to calculate the formula for the span and critical distance between the observation point and the transmission line.

Three-Dimensional Modelling of Heat Transfer in Micro-Channels With Synthetic Jet

2010 ◽  
Author(s):  
Ann Lee ◽  
Victoria Timchenko ◽  
Guan H. Yeoh ◽  
John A. Reizes
Keyword(s):  
Heat Transfer ◽  
Silicon Substrate ◽  
Three Dimensional ◽  
Synthetic Jet ◽  
Numerical Results ◽  
Maximum Temperature ◽  
Complex Conjugate ◽  
Two Dimensional ◽  
Flow And Heat Transfer ◽  
Micro Channels

An in-house computer code is developed and applied to investigate the effect of a synthetic jet on heat transfer rates in forced convection of water in silicon micro-channels etched in the rear side of the silicon substrate. To account for the deflection of the membrane located at the bottom of the actuator cavity, a moving mesh technique to solve the flow and heat transfer is purposefully adopted. The governing equations are transformed into the curvilinear coordinate system in which the grid velocities evaluated are then fed into the computation of the flow in the cavity domain thus allowing the conservation equations of mass, momentum and energy to be solved within the stationary computational domain. The fully three-dimensional model considers the SIMPLE method to link the pressure and velocity. A heat flux of 1 MW/m2 is applied at the surface of the top of the silicon wafer and the resulting complex, conjugate heat transfer through the silicon substrate is included. The hydrodynamics feature of the flow is validated against existing experimental results and verified against numerical results from commercial package ANSYS CFX 11.0. Good agreement has been achieved. To track the development of the flow and heat transfer when the actuator is switched on, numerical results of 20 full cycles of the actuator are simulated. When the actuator is switched on, noticeable temperature drop is observed at all points in the substrate from those which existed when there has been a steady water flow in the channel. At the end of 20th cycle of actuation, the maximum temperature in the wafer has reduced by 5.4 K in comparison with the steady flow values. In comparison with the two-dimensional study which account for 17K reduction, it indicates that synthetic jet has only smaller beneficial cooling and has been over-estimated in the previous two-dimensional study.

Numerical Computation for Flow-Induced Oscillations of a Circular Cylinder

2010 ◽  
Author(s):  
Norio Kondo
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
High Reynolds Number ◽  
Numerical Results ◽  
High Mass ◽  
Mass Ratio ◽  
Reynolds Number Flow ◽  
Wide Range ◽  
Number Flow ◽  
High Reynolds

This paper presents numerical results for flow-induced oscillations of an elastically supported circular cylinder, which is immersed in a high Reynolds number flow. The flow-induced oscillations of the circular cylinder at subcritical Reynolds numbers have been investigated by many researchers, and the interested phenomena with respect to the oscillations have been found in a wide range of the Scruton number. For the flow-induced oscillation of the circular cylinder with high mass ratio, it is well-known that there is the peak value of amplitudes at near the critical reduced velocity. Therefore, we computer flow-induced oscillations of a circular cylinder with a mass ratio of 8, which is placed in a high Reynolds number flow, by three-dimensional simulation, and the numerical results are compared with the results of flow-induced oscillations of the circular cylinder immersed in a subcritical Reynolds number flow.

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