ELF Electric Field Coupling to Dielectric Spheroidal Models of Biological Objects

Shiau, Yih; Valentino, A.

doi:10.1109/tbme.1981.324815

Cited by 43 publications

(9 citation statements)

References 8 publications

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“…Examples of analytic solutions in homogeneous geometric shapes for electric-eld exposure are available in Spiegel, (88) Shiau and Valentino, (89) Kaune and McCreary, (90) Kaune et al, (91) Foster and Schwan, (92) and Hart. (93) Measurements of currents within the body have also been performed.…”

Section: Homogeneous Bodies Of Revolution and Other Simpli Ed Body Shmentioning

confidence: 99%

Evaluation of Biological Effects, Dosimetric Models, and Exposure Assessment Related to ELF Electric- and Magnetic-Field Guidelines

Kavet

Stuchly²,

Bailey³

et al. 2001

Applied Occupational and Environmental Hygiene

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Several organizations worldwide have issued guidelines to limit occupational and public exposure to electric and magnetic fields and contact currents in the extremely low frequency range (<3 kilohertz). In this paper, we evaluate relevant developments in biological and health research, computational methods for estimating dosimetric quantities, and exposure assessment, all with an emphasis on the power frequency (60 hertz in North America, 50 hertz in Europe). The aim of each guideline is to prevent acute neural effects of induced electric fields. An evaluation of epidemiological and laboratory studies of neurobiological effects identified peripheral nerve stimulation as the response most suitable for establishing a magnetic-field guideline. Key endpoints that merit further study include reversal of evoked potentials; cardiovascular function, as measured by heart rate and heart rate variability; and sleep patterns. High-resolution computations of induced electric fields and current densities in anatomically correct human models are now achieved with finite-difference methods. The validity and limitations of these models have been demonstrated by computations in regular geometric shapes, using both analytic and numeric computations. Calculated values for average dosimetric quantities are typically within a few percent for the two approaches. However, maximum induced quantities are considerably overestimated by numerical methods, particularly at air interfaces. Overestimates are less pronounced for the upper 99th percentile level of a dosimetric quantity, making this measure a more useful indicator of maximum dose. Neural stimulation thresholds are dependent on the electric field around the excitable cell rather than on the current density, making the former preferable for expression of basic restrictions based on nervous system function. Furthermore, modeling data indicate that the induced electric field is much less strongly influenced by tissue conductivity than is the induced current density. In the electric utility industry, most magnetic-field exposures at or near guideline levels occur in highly nonuniform fields. Two methods are described for simplified estimation of induced quantities in such fields, with each method using as input modeling results for uniform field exposure. These methods have practical value for assessing occupational exposures relative to guideline levels.

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Section: Homogeneous Bodies Of Revolution and Other Simpli Ed Body Shmentioning

confidence: 99%

Evaluation of Biological Effects, Dosimetric Models, and Exposure Assessment Related to ELF Electric- and Magnetic-Field Guidelines

Kavet

Stuchly²,

Bailey³

et al. 2001

Applied Occupational and Environmental Hygiene

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“…Numerous evaluations of the induced electric ®elds and currents have been previously performed for simpli®ed or semi-realistic models of the human body, e.g. Shiau and Valentino [1981], Kaune and McCreary [1985], Spiegel [1981], Chiba et al [1984], Chen et al [1986], Dimbylow [1987], Xi et al [1994], Stuchly and Zhao [1996]. Actual measurements have also been performed of the short circuit current in people or the models exposed to a uniform electric ®eld [Deno and Zaffanella, 1982;Kaune and Forsythe, 1985;Kaune et al, 1987].…”

Section: Introductionmentioning

confidence: 99%

Inter-laboratory comparison of numerical dosimetry for human exposure to 60 Hz electric and magnetic fields

Stuchly

Gandhi

2000

Bioelectromagnetics

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In recent years, with the availability of high resolution models of the human body, numerical computations of induced electric fields and currents have been made in more than one laboratory for various exposure conditions. Despite the verification of computational methods, questions are often asked about the reliability of these data. In this paper, computati onal results from two laboratories that presented data in compatible formats are compared, supplemented with additional data from the third laboratory. Two exposures to uniform fields at 60 Hz are evaluated. The human body models used in the computations are different and so are the computation al methods and codes. There are some differences in the conductivity values used for some of the tissues, as well. The results of the comparison confirm that these data are reliable, as the overall agreement is reasonably good and the differences can be rationally explained. This comparison also underscores the importance of accurate data on the dielectric properties of tissues. Bioelectromagnetics 21:167–174, 2000. © 2000 Wiley‐Liss, Inc.

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“…When a grounded semi‐spheroid with homogeneous conductivity σ is placed in external electric field ( E 0 ) normal to the ground (see Figure (a)), field E i induced inside the semi‐spheroid is uniform regardless of position, and can be expressed as follows:

E_{i} = \frac{E_{o}}{1 + (\frac{σ}{ω ε_{0}} - 1) (u_{0}^{2} - 1) \{u_{0} {coth}^{- 1} (u_{0}) - 1\}}

…”

Section: Methods Of Numerical Analysismentioning

confidence: 99%

Electric fields induced inside numerical human model standing on ground plane with elevated arms in uniform electric field at power frequency

Tarao

Takei

Hayashi

et al. 2018

Elect Comm in Japan

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In the ICNIRP guidelines on the protection of human exposure to low frequency electric and magnetic fields, the reference levels are given based on the maximum value of induced electric fields (EF’s) inside a numerical human model that stands erect on ground plane with both hands down by its sides. In this contribution, numerical results on the induced EF’s inside a numerical human model standing with elevated arms in a 50 Hz uniform EF, are illustrated. The effect of the arm elevation angle on the maximum EF is discussed. It is found that, when both arms are raised overhead, the maximum values of the induced EF in the nervous system tissues increase by 20–35% compared with those obtained when both hands are down by its sides, which falls within the reduction factor of 2.4.

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ELF Electric Field Coupling to Dielectric Spheroidal Models of Biological Objects

Cited by 43 publications

References 8 publications

Evaluation of Biological Effects, Dosimetric Models, and Exposure Assessment Related to ELF Electric- and Magnetic-Field Guidelines

Evaluation of Biological Effects, Dosimetric Models, and Exposure Assessment Related to ELF Electric- and Magnetic-Field Guidelines

Inter-laboratory comparison of numerical dosimetry for human exposure to 60 Hz electric and magnetic fields

Electric fields induced inside numerical human model standing on ground plane with elevated arms in uniform electric field at power frequency

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