The propagation of magneto-thermo-viscoelastic plane waves in a parallel union of the Kelvin and Maxwell bodies

1971 ◽  
Vol 70 (2) ◽  
pp. 343-350 ◽  
Author(s):  
D. S. Chandrasekhariah
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Electromagnetic Field ◽  
Wave Propagation ◽  
Thermal Field ◽  
Plane Waves ◽  
Viscoelastic Body ◽  
Longitudinal Component ◽  
Transverse Component ◽  
Wave Travel

AbstractThe propagation of plane waves in a viscoelastic body representing a parallel union of the Kelvin and Maxwell bodies placed in a magneto-thermal field is investigated. It is shown that the longitudinal component of the wave is in general coupled with a transverse component and the wave travels in two families. In particular if the primary magnetic field is either parallel or perpendicular to the direction of wave propagation, the three components of the wave travel unlinked, with either the longitudinal component or the transverse components unaffected by the presence of the electromagnetic field. If the electrical conductivity of the solid is infinite the effect of the primary magnetic field is to increase the values of the material constants. The effect of wave propagation on magnetic permeability is equivalent to an anisotropic rescaling of the primary magnetic field. Some of the results obtained in the earlier works are obtained as particular cases of the more general results derived here.

Magneto-thermo-elastic plane waves

1965 ◽  
Vol 61 (4) ◽  
pp. 939-944 ◽  
Author(s):  
C. M. Purushothama
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Shear Wave ◽  
Wave Velocity ◽  
Compression Wave ◽  
Thermal Field ◽  
Plane Waves ◽  
Elastic Plane ◽  
Magnetic Diffusivity ◽  
The Magnetic Field

AbstractThe combined effects of uniform thermal and magnetic fields on the propagation of plane waves in a homogeneous, initially unstressed, electrically conducting elastic medium have been investigated.When the magnetic field is parallel to the direction of wave propagation, the compression wave is purely thermo-elastic and the shear wave is purely magneto-elastic in nature. For a transverse magnetic field, the shear waves remain elastic whereas the compression wave assumes magneto-thermo-elastic character due to the coupling of all the three fields—mechanical, magnetic and thermal. In the general case, the waves polarized in the plane of the direction of wave propagation and the magnetic field are not only coupled but are also influenced by the thermal field, once again exhibiting the coupling of the three fields. The shear wave polarized transverse to the plane retains its magneto-elastic character.Notation.Hi = primary magnetic field components,ht = induced magnetic field components,To = initial thermal field,θ = induced thermal field,C = compression wave velocity.S = shear wave velocity,ui = displacement components,cv = specific heat at constant volume,k = thermal conductivity,η = magnetic diffusivity,μe = magnetic permeability,λ, μ = Lamé's constants,β = ratio of coefficient of volume expansion to isothermal compressibility.

Investigating flexible textile-based coils for wireless charging wearable electronics

2019 ◽  
Vol 50 (3) ◽  
pp. 333-345 ◽  
Author(s):  
Danmei Sun ◽  
Meixuan Chen ◽  
Symon Podilchak ◽  
Apostolos Georgiadis ◽  
Qassim S Abdullahi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Electromagnetic Field ◽  
Electric Field ◽  
Dimensional Stability ◽  
Screen Printing ◽  
Wearable Electronics ◽  
Wireless Charging ◽  
The Magnetic Field ◽  
Screen Printed

Smart and interactive textiles have been attracted great attention in recent years. This research explored three different techniques and processes in developing textile-based conductive coils that are able to embed in a garment layer. Coils made through embroidery and screen printing have good dimensional stability, although the resistance of screen printed coil is too high due to the low conductivity of the print ink. Laser cut coil provided the best electrical conductivity; however, the disadvantage of this method is that it is very difficult to keep the completed coil to the predetermined shape and dimension. The tested results show that an electromagnetic field has been generated between the textile-based conductive coil and an external coil that is directly powered by electricity. The magnetic field and electric field worked simultaneously to complete the wireless charging process.

scholarly journals Using the Carotazh Method to Determine the Electrical Characteristics of the Earth’s Subsoil

2021 ◽  
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Electromagnetic Field ◽  
Surface Impedance ◽  
Electromagnetic Waves ◽  
Dielectric Permeability ◽  
Electrical Characteristics ◽  
Measuring Systems ◽  
The Earth ◽  
The Magnetic Field

Logging is a detailed study of the structure of the well incision by descent and ascent of a geophysical probe. It is often used to determine the electrical conductivity of terrestrial depths. To do this, the sides of the well deepen the electrodes, and they are fed into the depths of a constant electric current. However, if you use natural or artificial electromagnetic waves, it becomes possible to determine the dielectric permeability of terrestrial rocks at depth. To do this, the surface impedance is first measured on the surface of the earth, and then by measuring at a certain frequency of the electromagnetic field in the well hole, the electrical conductivity and dielectric permeability of terrestrial rocks are calculated by fairly simple formulas. Such measurements can be carried out by standard measuring systems, adding only a narrow frame with wire winding to measure the magnetic field.

Electromagneto-Thermoelastic Plane Waves in Solids With Thermal Relaxation

1972 ◽  
Vol 39 (1) ◽  
pp. 108-113 ◽  
Author(s):  
A. H. Nayfeh ◽  
S. Nemat-Nasser
Keyword(s):  
Magnetic Field ◽  
Relaxation Time ◽  
Thermal Field ◽  
Plane Waves ◽  
Electric Displacement ◽  
Thermal Relaxation ◽  
Displacement Current ◽  
Perturbation Techniques ◽  
Thermoelastic Waves ◽  
The Magnetic Field

Perturbation techniques are used to study the influence of small thermoelastic and magnetoelastic couplings on the propagation of plane electromagneto-thermoelastic waves in an unbounded isotropic medium. The thermal relaxation time of heat conduction, and the electric displacement current are included in the analysis. It is found that the thermal field may affect transverse motions, and that the magnetic field may affect motions that occur parallel to its line of action.

The propagation of magneto-thermo-elastic plane waves

1963 ◽  
Vol 59 (2) ◽  
pp. 483-488 ◽  
Author(s):  
A. J. Willson
Keyword(s):  
Electromagnetic Field ◽  
Plane Wave ◽  
Dispersion Equation ◽  
Thermal Field ◽  
Plane Waves ◽  
Elastic Field ◽  
Principal Result ◽  
Elastic Plane

In a recent paper (1), Paria has discussed the propagation through a solid of a certain type of magneto-thermo-elastic plane wave. The analysis is essentially a reconciliation of the equations governing three fields: the electromagnetic field, the thermal field and the elastic field, which interact one with another. The principal result which was obtained was the dispersion equation connecting the frequency and the wavelength of waves of this type.

On magneto-thermo-elastic plane waves

1962 ◽  
Vol 58 (3) ◽  
pp. 527-531 ◽  
Author(s):  
G. Paria
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Elastic Wave ◽  
Plane Waves ◽  
Low Frequency ◽  
Coupling Factor ◽  
Elastic Wave Velocity ◽  
Elastic Plane ◽  
Elastic Coupling ◽  
Finite Electrical Conductivity

ABSTRACTThe propagation of plane waves in a thermo-elastic body placed in a magnetic field has been investigated. It is shown that the problem can be reduced to one of pure thermo-elasticity, provided that the longitudinal elastic wave velocity is suitably increased in the case of infinite electrical conductivity. For finite electrical conductivity and low frequency, however, the thermo-elastic coupling factor is to be increased.

A MULTILAYER CONDUCTING EARTH IN THE FIELD OF PLANE WAVES

1966 ◽  
Vol 44 (1) ◽  
pp. 81-89
Author(s):  
H. W. Dosso
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Field ◽  
Electromagnetic Waves ◽  
Plane Waves ◽  
Conducting Medium ◽  
Continuous Change ◽  
Electric And Magnetic Field ◽  
Thick Layers

A multilayer plane conducting earth in the field of plane electromagnetic waves is treated. Each of several thick layers is divided into a sufficient number of sublayers, with changing conductivity, to represent to a good approximation a continuous change in conductivity. Expressions for the amplitudes and phases of the electric- and magnetic-field components are obtained and evaluated for several different conductivity distributions. The conductivities and frequencies considered are of interest in geophysics. The results obtained indicate that the amplitudes and phases of the varying electromagnetic-field components are affected strongly by the inhomogeneity of the conducting medium.

scholarly journals Magnetoelastic plane waves in rotating media in thermoelasticity of type II (G-N model)

2004 ◽  
Vol 2004 (71) ◽  
pp. 3917-3929 ◽  
Author(s):  
S. K. Roychoudhuri ◽  
Manidipa Banerjee (Chattopadhyay)
Keyword(s):  
Magnetic Field ◽  
Energy Loss ◽  
Phase Velocity ◽  
Specific Energy ◽  
Thermal Field ◽  
Plane Waves ◽  
Transverse Magnetic ◽  
Thermal Parameters ◽  
First Order ◽  
Specific Energy Loss

A study is made of the propagation of time-harmonic plane waves in an infinite, conducting, thermoelastic solid permeated by a uniform primary external magnetic field when the entire medium is rotating with a uniform angular velocity. The thermoelasticity theory of type II (G-N model) (1993) is used to study the propagation of waves. A more general dispersion equation is derived to determine the effects of rotation, thermal parameters, characteristic of the medium, and the external magnetic field. If the primary magnetic field has a transverse component, it is observed that the longitudinal and transverse motions are linked together. For low frequency (χ≪1,χbeing the ratio of the wave frequency to some standard frequencyω∗), the rotation and the thermal field have no effect on the phase velocity to the first order ofχand then this corresponds to only one slow wave influenced by the electromagnetic field only. But to the second order ofχ, the phase velocity, attenuation coefficient, and the specific energy loss are affected by rotation and depend on the thermal parameterscT,cTbeing the nondimensional thermal wave speed of G-N theory, and the thermoelastic couplingεT, the electromagnetic parametersεH, and the transverse magnetic fieldRH. Also for large frequency, rotation and thermal field have no effect on the phase velocity, which is independent of primary magnetic field to the first order of (1/χ) (χ≫1), and the specific energy loss is a constant, independent of any field parameter. However, to the second order of (1/χ), rotation does exert influence on both the phase velocity and the attenuation factor, and the specific energy loss is affected by rotation and depends on the thermal parameterscTandεT, electromagnetic parameterεH, and the transverse magnetic fieldRH, whereas the specific energy loss is independent of any field parameters to the first order of (1/χ).

Magnetic Field Spectroheliograms from the San Fernando Observatory

1971 ◽  
Vol 43 ◽  
pp. 329-339 ◽  
Author(s):  
Dale Vrabec
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Spiral Structure ◽  
Longitudinal Component ◽  
Solar Telescope ◽  
Solar Magnetic Fields ◽  
San Fernando ◽  
Field Lines ◽  
The Magnetic Field ◽  
Field Network

Zeeman spectroheliograms of photospheric magnetic fields (longitudinal component) in the CaI 6102.7 Å line are being obtained with the new 61-cm vacuum solar telescope and spectroheliograph, using the Leighton technique. The structure of the magnetic field network appears identical to the bright photospheric network visible in the cores of many Fraunhofer lines and in CN spectroheliograms, with the exception that polarities are distinguished. This supports the evolving concept that solar magnetic fields outside of sunspots exist in small concentrations of essentially vertically oriented field, roughly clumped to form a network imbedded in the otherwise field-free photosphere. A timelapse spectroheliogram movie sequence spanning 6 hr revealed changes in the magnetic fields, including a systematic outward streaming of small magnetic knots of both polarities within annular areas surrounding several sunspots. The photospheric magnetic fields and a series of filtergrams taken at various wavelengths in the Hα profile starting in the far wing are intercompared in an effort to demonstrate that the dark strands of arch filament systems (AFS) and fibrils map magnetic field lines in the chromosphere. An example of an active region in which the magnetic fields assume a distinct spiral structure is presented.

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