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Interaction of Extremely Low–Frequency Electromagnetic Fields
fields and biological objects. The object was a dielectric spheroidal model inside two nonspherical spheroids: a prolate dielectric spheroid and an oblate dielectric spheroid. This
simple expression was presented for the internal electric field strengths when the dielectric spheroids are exposed to uniform ELF electric fields. The induced internal electric
fields, current densities, and absorbed internal powers are calculated for various geometric shapes of the prolate dielectric spheroid and the oblate dielectric spheroid. Their
numerical results are illustrated through graphics for various geometric shapes of spheroids. It shows that the relative position of the spheroid with respect to the orientation of
the applied electric fields is the extremely important parameter that affects the electric
field coupling considerably. In order to clarify the electric field coupling to human beings,
Spiegel (1977b) developed a numerical method for predicting currents and normal electric
field distributions induced in humans situated in the vicinity of transmission lines. His
technique is based on the method of moment (MoM) in which the human body is modeled as a collection of straight cylindrical segments. Its lengths and radii are comparable
to the section of the body modeled. Three scenarios are especially considered: a person
wearing an insulating outfit standing on the ground beneath transmission lines, an individual having solid ground contact, and a lineman working very close to an energized
conductor. DiPlacido, Shih, and Ware (1978) used a CSM to calculate induced currents in
grounded and ungrounded human models consisting of 36 spheres. They also presented a
theoretical analysis of the proximity effect of operator on electric field meter performance.
Numerical techniques used for mathematical models range from solution of an
integral equation by the MoM (Spiegel 1981), the FEM (Chiba et al. 1984; Chiba and
Isaka 1997, 1999, 2000; Chiba, Isaka, and Kaune 1998; Isaka et al. 1987), and the Finite
Difference Method (FDM) (Chen, Chuang, and Lin 1986; Hart 1990, 1992a; Dimbylow
1987, 1988). In order to investigate the biological effect of 60 Hz electric fields on experimental animals, Spiegel (1981) developed human and baboon models by using a large
number of small cubical blocks. This array of small cubical blocks was arranged to best
fit to the object’s contour, and to calculate the internal current densities attributed to
the grounded and ungrounded models using integral equations. Chen, Chuang, and
Lin (1986) developed a numerical method based on a surface-charge integral equation
(SCIE) that can be applied to a realistically shaped phantom. This method yielded a
mere average local current density. Their research was to quantify the interaction of
ELF-LF electric fields with a human body of realistic and homogeneous shape and arbitrary posture, standing in a realistic environment. This numerical method based on an
SCIE can calculate the induced electric field on the body surface and inside the body,
the induced body current, and the effect of the grounding impedance. Their calculation
also applied to the model using guinea pigs. Later on, Chuang and Chen (1989) applied
the SCIE method to a three-dimensional heterogeneous biological body. This numerical
method based on the combination of a pair of SCIE and an impedance network method
was applied to calculate the internal electric fields and currents inside three-dimensional heterogeneous biological bodies with arbitrary grounding impedance induced by
ELF-LF electric fields. They confirmed the validity of the method by comparing numerical results and analytical solutions involving conducting concentric spheres.
Kaune and McCreary (1985) used a combined charge-simulation/finite-difference
approach to model humans and animals exposed to vertical uniform 60 Hz electric fields.
Interaction of Extremely Low–Frequency Electromagnetic Fields
fields and biological objects. The object was a dielectric spheroidal model inside two nonspherical spheroids: a prolate dielectric spheroid and an oblate dielectric spheroid. This
simple expression was presented for the internal electric field strengths when the dielectric spheroids are exposed to uniform ELF electric fields. The induced internal electric
fields, current densities, and absorbed internal powers are calculated for various geometric shapes of the prolate dielectric spheroid and the oblate dielectric spheroid. Their
numerical results are illustrated through graphics for various geometric shapes of spheroids. It shows that the relative position of the spheroid with respect to the orientation of
the applied electric fields is the extremely important parameter that affects the electric
field coupling considerably. In order to clarify the electric field coupling to human beings,
Spiegel (1977b) developed a numerical method for predicting currents and normal electric
field distributions induced in humans situated in the vicinity of transmission lines. His
technique is based on the method of moment (MoM) in which the human body is modeled as a collection of straight cylindrical segments. Its lengths and radii are comparable
to the section of the body modeled. Three scenarios are especially considered: a person
wearing an insulating outfit standing on the ground beneath transmission lines, an individual having solid ground contact, and a lineman working very close to an energized
conductor. DiPlacido, Shih, and Ware (1978) used a CSM to calculate induced currents in
grounded and ungrounded human models consisting of 36 spheres. They also presented a
theoretical analysis of the proximity effect of operator on electric field meter performance.
Numerical techniques used for mathematical models range from solution of an
integral equation by the MoM (Spiegel 1981), the FEM (Chiba et al. 1984; Chiba and
Isaka 1997, 1999, 2000; Chiba, Isaka, and Kaune 1998; Isaka et al. 1987), and the Finite
Difference Method (FDM) (Chen, Chuang, and Lin 1986; Hart 1990, 1992a; Dimbylow
1987, 1988). In order to investigate the biological effect of 60 Hz electric fields on experimental animals, Spiegel (1981) developed human and baboon models by using a large
number of small cubical blocks. This array of small cubical blocks was arranged to best
fit to the object’s contour, and to calculate the internal current densities attributed to
the grounded and ungrounded models using integral equations. Chen, Chuang, and
Lin (1986) developed a numerical method based on a surface-charge integral equation
(SCIE) that can be applied to a realistically shaped phantom. This method yielded a
mere average local current density. Their research was to quantify the interaction of
ELF-LF electric fields with a human body of realistic and homogeneous shape and arbitrary posture, standing in a realistic environment. This numerical method based on an
SCIE can calculate the induced electric field on the body surface and inside the body,
the induced body current, and the effect of the grounding impedance. Their calculation
also applied to the model using guinea pigs. Later on, Chuang and Chen (1989) applied
the SCIE method to a three-dimensional heterogeneous biological body. This numerical
method based on the combination of a pair of SCIE and an impedance network method
was applied to calculate the internal electric fields and currents inside three-dimensional heterogeneous biological bodies with arbitrary grounding impedance induced by
ELF-LF electric fields. They confirmed the validity of the method by comparing numerical results and analytical solutions involving conducting concentric spheres.
Kaune and McCreary (1985) used a combined charge-simulation/finite-difference
approach to model humans and animals exposed to vertical uniform 60 Hz electric fields.