2 edition of effect of the surrounding media on the distribution of electromagnetic fields in a conductor found in the catalog.
effect of the surrounding media on the distribution of electromagnetic fields in a conductor
W. H. B. Cooper
Written in English
Thesis(Ph.D.) - Loughborough University of Technology 1970.
|Statement||by W.H.B. Cooper.|
Electromagnetic fields, similar to those found in overhead power lines, can have a biological effect on human cells, an effect that could contribute . Basic restriction: restriction on exposure to time-varying electric, magnetic, and electromagnetic fields that are based directly on established health effects. Depending on the frequency of the field, the physical quantities used to specify these restrictions are current density (J), SAR, and power density (S).
A large body of literature exists on the response of tissues to electromagnetic fields, primarily in the extremely-low-frequency (ELF) and microwave-frequency ranges. In general, the reported effects of radiofrequency (RF) radiation on tissue and organ systems have been attributed to thermal interactions, although the existence of nonthermal effects at low field intensities is still a subject. Some people use "electromagnetic" to mean exactly the same as we mean by EMFs - the collective concept of electric and magnetic fields. But some people use it to mean specifically the situation at higher frequencies where the two fields are coupled together .
Providing experimental results and comparisons from the authors' personal research, "Electromagnetic Modeling by Finite Element Methods" supplies techniques to implement FEM for solving Maxwell's equations, analyze electrical and magnetic losses, determine the behavior of electrical machines, evaluate force distribution on a magnetic medium. The potential effects of electromagnetic fields on human health vary widely depending on the frequency and intensity of the fields. The potential health effects of the very low frequency EMFs surrounding power lines and electrical devices are the subject of on-going research and a significant amount of public debate.
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The effect of the surrounding media on the distribution of electromagnetic fields in a conductor Author: Cooper, W. Awarding Body: Loughborough University of Technology Current Institution: Loughborough University Date of Award: Author: W.H.B.
Cooper. Publisher Summary. Macroscopic electrodynamics is concerned with the study of electromagnetic fields in space that is occupied by matter. Electrodynamics deals with physical quantities averaged over elements of volume that are physically infinitesimal and ignore the microscopic variations of the quantities that result from the molecular structure of matter.
The changes of the fields are always delayed relative to the changes of the sources, reflecting the finite speed of propagation of electromagnetic waves. Under the assumption that this effect can be ignored, it is possible to obtain the electromagnetic fields by considering "stationary currents at every instant".
Electromagnetism - Electromagnetism - Effects of varying magnetic fields: The merger of electricity and magnetism from distinct phenomena into electromagnetism is tied to three closely related events.
The first was Hans Christian Ørsted’s accidental discovery of the influence of an electric current on a magnetic needle—namely, that magnetic fields are produced by electric currents. Sources and effects of electromagnetic fields - Vector fields - Different co-ordinate systems - Divergence theorem - Stoke s ostaticsCoulomb s law - Electric field intensity - Field due to point and continuous charges - Gauss s law and application - Electrical potential - Electric field and equipotential plots - Electric field in free space, Conductors, Dielectric - Dielectric Reviews: 2.
prediction of the existence of electromagnetic waves that travel with speed of light c=1/ µ0ε0. The reason is due to the fact that a changing electric field produces a magnetic field and vice versa, and the coupling between the two fields leads to the generation of electromagnetic waves.
The prediction was confirmed by H. Hertz in The class of media defined by (10) has been called that of axion media  or perfect electromagnetic conductor (PEMC) media and it has been previously studied in detail .
A medium belonging to. For this purpose, time-varying electromagnetic fields in media exhibiting a linearized form of hysteresis are considered.
The treatment is an extension of the uniqueness theorem for. This paper shows the effects of corona discharge in the lightning performance computation of overhead distribution lines. The analysis will involve different configurations in terms of line diameter and air conditions, focusing on the negative effect of corona discharge in the number of dangerous events that determine line flashovers.
Full article. polarizable and conducting media with negligible magnetic field; (2) currents as the source of the magnetic field coupled to magnetizable media with electromagnetic induction generat ing an electric field; and (3) electrodynamics where the electric and magnetic fields are of equal importance resulting in radi ating waves.
Any current carrying conductor has a magnetic field surrounding the conductor. If the conductor is curved into a helical then some of the magnetic field returns to the conductor inducing a back.
Possible effects of Electromagnetic Fields (EMF) on Human Health 7 lower frequencies and higher frequencies. Proper evaluation and assessment of possible health effects from long term exposure to IF fields are important because human exposure to such fields is increasing due to.
Electromagnetic field, a property of space caused by the motion of an electric charge. A stationary charge will produce only an electric field in the surrounding space. If the charge is moving, a magnetic field is also produced.
An electric field can be produced also by a changing magnetic field. serious research about electromagnetic fields (EMF) and potential adverse health effects started with the publication of a study by Mrs.
Nancy Wertheimer and Mr. Ed Leeper. Their epidemiological study was conducted in the Denver area and reported a higher occurrence of childhood cancer in residences located near high voltage power lines. Average Transition Conditions for Electromagnetic Fields at a Metascreen of Vanishing Thickness Edward F.
Kuester, Life Fellow, about a third of a wavelength in the surrounding media, and approximated by the ﬁelds of the continuous distribution of. These produce their effects by creating electrostatic fields in the tissues.
There may be a long cable enclosed in a rubber sheath. For MWD, there are usually a number of applicators, used singly, which are of different sizes to correspond with different body areas.
The therapeutic effect is achieved by creating electromagnetic fields in the. This graduate-level physics textbook provides a comprehensive treatment of the basic principles and phenomena of classical electromagnetism. While many electromagnetism texts use the subject to teach mathematical methods of physics, here the emphasis is on the physical ideas themselves.
Anupam Garg distinguishes between electromagnetism in vacuum and that in material media, stressing that the. Exposure to electromagnetic fields is not a new phenomenon. However, during the 20th century, environmental exposure to man-made electromagnetic fields has been steadily increasing as growing electricity demand, ever-advancing technologies and changes in social behaviour have created more and more artificial sources.
Maxwell’s equations and media. The great success of Maxwell’s equations lies partly in their simple prediction of electromagnetic waves and their simple characterization of materials in terms of conductivity σ [Siemens m-1], permittivity ε [Farads m-1], and permeability μ [Henries m-1].In vacuum we find σ = 0, ε = ε o, and μ = μ o, where ε o = × 2 and μ o = 4.
vacuum normally incident upon a planar perfect conductor at z ≥ 0, as illustrated in Figure (a). Step 1 of the general boundary-problem solution method of Section is simply to note that electromagnetic fields in the medium can be represented by superimposed uniform plane waves.
Ex(z,to) x Ex(z,t) reflected input x σ = ∞ σ = ∞. Personnel Training Publications: Magnetic Particle Testing (MT), Classroom Training Book Second Edition (eBook) Contains up-to-date information on many aspects of magnetic particle testing.
Organized to follow the body of knowledge outlined in CP () for Levels I and II.This equation evaluates the electric potential anywhere within an inhomogeneous volume conductor containing internal volume sources. The first term on the right-hand side of Equation involving i corresponds exactly to Equation and thus represents the contribution of the volume source.
The effect of inhomogeneities is reflected in the second integral, where (σ j" - σ j ')Φ j is an. Corresponding effects are not separable and usually called by different names like proximity or crowding effect, edge effect, transition to skin-effect.
At medium frequencies the resistance p.u.l. increases and the internal conductor inductance p.u.l. decreases because of shrinking conductor area with the current and magnetic fields.