Ronald Spiegel - Academia.edu (original) (raw)
Papers by Ronald Spiegel
Bioelectromagnetics, 1984
IEEE Transactions on Biomedical Engineering, 1976
The induced fields, currents, and power absorbed by spherical models of humans or animals when ex... more The induced fields, currents, and power absorbed by spherical models of humans or animals when exposed to extremely low frequency (ELF) electromagnetic fields are calculated. Spherical models can be expected to provide values of the right order of magnitude. The induced fields are a sum of the quasistatic solutions for a sphere irradiated by a uniform electric and magnetic field. Calculations are provided for ELF fields emanating from the proposed Navy's Sanguine antenna and extra high voltage (EHV)/ultra high voltage (UHV) transmission lines proposed by the utility industry. The question of biological hazards from exposure to fields of these systems is also considered.
IEEE Transactions on Biomedical Engineering, 1976
The induced fields, currents, and power absorbed by spherical models of humans or animals when ex... more The induced fields, currents, and power absorbed by spherical models of humans or animals when exposed to extremely low frequency (ELF) electromagnetic fields are calculated. Spherical models can be expected to provide values of the right order of magnitude. The induced fields are a sum of the quasistatic solutions for a sphere irradiated by a uniform electric and magnetic field. Calculations are provided for ELF fields emanating from the proposed Navy's Sanguine antenna and extra high voltage (EHV)/ultra high voltage (UHV) transmission lines proposed by the utility industry. The question of biological hazards from exposure to fields of these systems is also considered.
Bioelectromagnetics, 1986
The specific absorption rate (SAR) in a biological sample irradiated by electromagnetic fields be... more The specific absorption rate (SAR) in a biological sample irradiated by electromagnetic fields between the metal plates of a transmission line can be altered significantly by the spacing of the metal plates and the distance between neighboring samples. The SAR in spherical biological samples is calculated for a number of neighboring sample arrangements and metal-plate spacings by using the method of images and induced dipole coupling. For a decrease in metal-plate spacing, the derived equations predict an increase in SAR within a sample and a decrease in SAR with a decrease in neighboring-sample spacing. The calculations are compared with measurements made with the aid of an array of I-in radius metal hemispheres on the lower plate of two parallel plates (thus forming an image system). The hemisphere on which measurements are taken is insulated from the metal plate and is connected via a coaxial center conductor to an HP 3582A spectrum analyzer that measures the voltage and hence the electric field intensity at the hemisphere. Measurements made at a frequency where wavelength is large compared with sample size (48 Hz) are in good agreement with calculations.
Electromagnetic (EM) cloaks, based on spatial transformations, can potentially be utilized as shi... more Electromagnetic (EM) cloaks, based on spatial transformations, can potentially be utilized as shielding devices for antennas in close proximity with multiple antenna arrangements as well as highly scattering environments. In these environments each antenna can be enclosed in a cloak that is designed to be shield at the transmitting frequencies of the neighboring antennas, but assumes free space values for the shielded antenna so it can radiate unimpeded. Perfect EM cloaking is, however, difficult owing to the anisotropic, inhomogeneous material parameters of the cloak. The physical embodiment of such structures, as well as numerical calculations, is exceedingly difficult, if not impossible, for realistic 3-D structures. To overcome these immense issues, this research utilizes dispersive media (Drude or Lorentz models) that can minimize some of the problems (anisotropic, inhomogeneous material parameters) associated with “true” cloaks, but can yield similar cloaking properties. The r...
Electromagnetic (EM) cloaks, based on spatial transformations, can potentially be utilized as shi... more Electromagnetic (EM) cloaks, based on spatial transformations, can potentially be utilized as shielding devices for antennas in close proximity with multiple antenna arrangements as well as highly scattering environments. In these environments each antenna can be enclosed in a cloak that is designed to be shield at the transmitting frequencies of the neighboring antennas, but assumes free space values for the shielded antenna so it can radiate unimpeded. Perfect EM cloaking is, however, difficult owing to the anisotropic, inhomogeneous material parameters of the cloak. The physical embodiment of such structures, as well as numerical calculations, is exceedingly difficult, if not impossible, for realistic 3-D structures. To overcome these immense issues, this research utilizes dispersive media (Drude or Lorentz models) that can minimize some of the problems (anisotropic, inhomogeneous material parameters) associated with “true” cloaks, but can yield similar cloaking properties. The r...
IEEE Transactions on Power Electronics, 1997
The paper describes a variable speed wind generation system where fuzzy logic principles are used... more The paper describes a variable speed wind generation system where fuzzy logic principles are used for efficiency optimization and performance enhancement control. A squirrel cage induction generator feeds the power to a double-sided pulse width modulated converter system which pumps power to a utility grid or can supply to an autonomous system. The generation system has fuzzy logic control with vector control in the inner loops. A fuzzy controller tracks the generator speed with the wind velocity to extract the maximum power. A second fuzzy controller programs the machine flux for light load efficiency improvement, and a third fuzzy controller gives robust speed control against wind gust and turbine oscillatory torque. The complete control system has been developed, analyzed, and validated by simulation study. Performances have then been evaluated in detail.
IEEE Transactions on Microwave Theory and Techniques, 1982
The thermal response of a human in the near-zone of an antenna was determined by numerical proced... more The thermal response of a human in the near-zone of an antenna was determined by numerical procedures. The approach taken was to modify the heat transfer equations for man in air to account for thermal Ioadkrg due to the energy absorbed from the radiating antenna. The absorbed power density distribution in the human body was determined by considering the body and antenna to be a coupled system in which the resulting system of equations were solved by moment method procedures. This information was then analyzed by a thermal response model consisting of a series of transient conduction equations with internal heat generation due to metabolism, internal convective heat transfer due to blood flow, external interaction by convection and radiation, and cooling of the skin by sweating and evaporation. Internal heating patterns were calculated for two cases a human in the near-zone of a quarter-wave monopole and a half-wave dipole operating at 45 and 200 MHz, respectively. It was found that negligible heating occurred for antennas with input power levels of less than 50 W'.
IEEE Transactions on Microwave Theory and Techniques, 1984
For humans exposed to electromagnetic (EM) radiation, the resulting thermophysiologic response is... more For humans exposed to electromagnetic (EM) radiation, the resulting thermophysiologic response is not well understood. Because it is urdikely that this information will be determined from quantitative experimentation, it is necessary to develop theoretical models which predict the resultant thermat response after exposure to EM fields. Thesecalculations are difficult and involved because the human thermoregulatory system is very complex. In this paper, the important mmrericaf models are reviewed and possibilities for future development are discussed.
IEEE Transactions on Microwave Theory and Techniques, 1986
The rate of the radio-frequency energy deposition in a model of the human body exposed in the nea... more The rate of the radio-frequency energy deposition in a model of the human body exposed in the near-field of a resonant dipole at 350 MHz was calculated using the moment method. Detailed maps of the electric-field intensity in a similar model under the same exposure conditions were obtained using a computer-controlled scanning system and an implantable electric-field probe. A comparison
IEEE Transactions on Microwave Theory and Techniques, 1986
The rate of the radio-frequency energy deposition in a model of the human body exposed in the nea... more The rate of the radio-frequency energy deposition in a model of the human body exposed in the near-field of a resonant dipole at 350 MHz was calculated using the moment method. Detailed maps of the electric-field intensity in a similar model under the same exposure conditions were obtained using a computer-controlled scanning system and an implantable electric-field probe. A comparison
IEEE Transactions on Microwave Theory and Techniques, 1986
The rate of the radio-frequency energy deposition in a model of the human body exposed in the nea... more The rate of the radio-frequency energy deposition in a model of the human body exposed in the near-field of a resonant dipole at 350 MHz was calculated using the moment method. Detailed maps of the electric-field intensity in a similar model under the same exposure conditions were obtained using a computer-controlled scanning system and an implantable electric-field probe. A comparison
IEEE Transactions on Biomedical Engineering, 1987
Bioelectromagnetics
Electromagnetic fields can interact with biological tissue both electrically and mechanically. Th... more Electromagnetic fields can interact with biological tissue both electrically and mechanically. This study investigated the mechanical interaction between brain tissue and an extremely-low-frequency (ELF) electric field by measuring the resultant vibrational amplitude. The exposure cell is a section of X-band waveguide that was modified by the addition of a center conductor to form a small TEM cell within the waveguide structure. The ELF signal is applied to the center conductor of the TEM cell. The applied ELF electric field generates an electrostrictive force on the surface of the brain tissue. This force causes the tissue to vibrate at a frequency equal to twice the frequency of the applied sinusoidal signal. An X-band signal is fed through the waveguide, scattered by the vibrating sample, and detected by a phase-sensitive receiver. Using a time-averaging spectrum analyzer, a vibration sensitivity of approximately 0.2 nmPp can be achieved. The amplitude of the brain tissue vibrational response is constant for vibrational frequencies below 50 Hz; between 50 and 200 Hz resonant phenomena were observed; and above 200 Hz the amplitude fall-off is rapid.
Artificial intelligence techniques, such as fuzzy logic, neural network, and genetic algorithm, a... more Artificial intelligence techniques, such as fuzzy logic, neural network, and genetic algorithm, are recently showing a lot of promise in the application of power electronic systems. The paper describes the control strategy development, design, and experimental performance evaluation of a fuzzy-logicbased variable-speed wind generation system that uses a cagetype induction generator and double-sided pulsewidth-modulated (PWM) converters. The system can feed a utility grid maintaining unity power factor at all conditions or can supply an autonomous load. The fuzzy-logic-based control of the system helps to optimize efficiency and enhance performance. A complete 3.5-kW generation system has been developed, designed, and thoroughly evaluated by laboratory tests, in order to validate the predicted performance improvements. The system gives excellent performance and can easily be translated to a larger size in the field.
IEEE Transactions on Biomedical Engineering, 1989
A finite-difference time-domain technique was used to calculate the specific absorption rate (SAR... more A finite-difference time-domain technique was used to calculate the specific absorption rate (SAR) at various sites in a heterogeneous block model of man. The block model represented a close approximation to a full-scale heterogeneous phantom model. Both models were comprised of a skeleton, brain, lungs, and muscle. Measurements were conducted in the phantom model using an implantable electric-field probe and a computer-controlled data acquisition system. The calculation and measurement of SAR distributions were compared primarily in the head (including the neck) and chest. To obtain the necessary spatial resolution with the computer model, the head and neck were modeled with approximately 105,000 cells, while 86,000 cells were used to configure the chest. Planewave fields, polarized in the E orientation, were utilized to irradiate the models at an exposure frequency of 350 MHz. Reasonable correlation existed between the calculations and measurements.
IEEE Transactions on Biomedical Engineering, 2000
Distributions of the specific absorption rate (SAR) were measured in a full-scale heterogeneous m... more Distributions of the specific absorption rate (SAR) were measured in a full-scale heterogeneous model of man. The model contained a skeleton, brain, lungs, and muscle. All these tissues had dielectric properties close to those of the respective in vivo properties of actual tissues at the test frequencies. SAR's were measured for exposures in the far field at 160, 350, and 915 MHz for the E and H polarizations. A computer-controlled scanning system and an implantable, minimally perturbing electric field probe were used. The results are also compared with the SAR distributions previously measured in a homogeneous model.
IEEE Transactions on Microwave Theory and Techniques, 1986
The rate of the radio-frequency energy deposition in a model of the human body exposed in the nea... more The rate of the radio-frequency energy deposition in a model of the human body exposed in the near-field of a resonant dipole at 350 MHz was calculated using the moment method. Detailed maps of the electric-field intensity in a similar model under the same exposure conditions were obtained using a computer-controlled scanning system and an implantable electric-field probe. A comparison
IEEE Transactions on Biomedical Engineering, 2000
Distributions of the specific absorption rate (SAR) were measured in a full-scale heterogeneous m... more Distributions of the specific absorption rate (SAR) were measured in a full-scale heterogeneous model of man. The model contained a skeleton, brain, lungs, and muscle. All these tissues had dielectric properties close to those of the respective in vivo properties of actual tissues at the test frequencies. SAR's were measured for exposures in the far field at 160, 350, and 915 MHz for the E and H polarizations. A computer-controlled scanning system and an implantable, minimally perturbing electric field probe were used. The results are also compared with the SAR distributions previously measured in a homogeneous model.
Bioelectromagnetics, 1984
IEEE Transactions on Biomedical Engineering, 1976
The induced fields, currents, and power absorbed by spherical models of humans or animals when ex... more The induced fields, currents, and power absorbed by spherical models of humans or animals when exposed to extremely low frequency (ELF) electromagnetic fields are calculated. Spherical models can be expected to provide values of the right order of magnitude. The induced fields are a sum of the quasistatic solutions for a sphere irradiated by a uniform electric and magnetic field. Calculations are provided for ELF fields emanating from the proposed Navy's Sanguine antenna and extra high voltage (EHV)/ultra high voltage (UHV) transmission lines proposed by the utility industry. The question of biological hazards from exposure to fields of these systems is also considered.
IEEE Transactions on Biomedical Engineering, 1976
The induced fields, currents, and power absorbed by spherical models of humans or animals when ex... more The induced fields, currents, and power absorbed by spherical models of humans or animals when exposed to extremely low frequency (ELF) electromagnetic fields are calculated. Spherical models can be expected to provide values of the right order of magnitude. The induced fields are a sum of the quasistatic solutions for a sphere irradiated by a uniform electric and magnetic field. Calculations are provided for ELF fields emanating from the proposed Navy's Sanguine antenna and extra high voltage (EHV)/ultra high voltage (UHV) transmission lines proposed by the utility industry. The question of biological hazards from exposure to fields of these systems is also considered.
Bioelectromagnetics, 1986
The specific absorption rate (SAR) in a biological sample irradiated by electromagnetic fields be... more The specific absorption rate (SAR) in a biological sample irradiated by electromagnetic fields between the metal plates of a transmission line can be altered significantly by the spacing of the metal plates and the distance between neighboring samples. The SAR in spherical biological samples is calculated for a number of neighboring sample arrangements and metal-plate spacings by using the method of images and induced dipole coupling. For a decrease in metal-plate spacing, the derived equations predict an increase in SAR within a sample and a decrease in SAR with a decrease in neighboring-sample spacing. The calculations are compared with measurements made with the aid of an array of I-in radius metal hemispheres on the lower plate of two parallel plates (thus forming an image system). The hemisphere on which measurements are taken is insulated from the metal plate and is connected via a coaxial center conductor to an HP 3582A spectrum analyzer that measures the voltage and hence the electric field intensity at the hemisphere. Measurements made at a frequency where wavelength is large compared with sample size (48 Hz) are in good agreement with calculations.
Electromagnetic (EM) cloaks, based on spatial transformations, can potentially be utilized as shi... more Electromagnetic (EM) cloaks, based on spatial transformations, can potentially be utilized as shielding devices for antennas in close proximity with multiple antenna arrangements as well as highly scattering environments. In these environments each antenna can be enclosed in a cloak that is designed to be shield at the transmitting frequencies of the neighboring antennas, but assumes free space values for the shielded antenna so it can radiate unimpeded. Perfect EM cloaking is, however, difficult owing to the anisotropic, inhomogeneous material parameters of the cloak. The physical embodiment of such structures, as well as numerical calculations, is exceedingly difficult, if not impossible, for realistic 3-D structures. To overcome these immense issues, this research utilizes dispersive media (Drude or Lorentz models) that can minimize some of the problems (anisotropic, inhomogeneous material parameters) associated with “true” cloaks, but can yield similar cloaking properties. The r...
Electromagnetic (EM) cloaks, based on spatial transformations, can potentially be utilized as shi... more Electromagnetic (EM) cloaks, based on spatial transformations, can potentially be utilized as shielding devices for antennas in close proximity with multiple antenna arrangements as well as highly scattering environments. In these environments each antenna can be enclosed in a cloak that is designed to be shield at the transmitting frequencies of the neighboring antennas, but assumes free space values for the shielded antenna so it can radiate unimpeded. Perfect EM cloaking is, however, difficult owing to the anisotropic, inhomogeneous material parameters of the cloak. The physical embodiment of such structures, as well as numerical calculations, is exceedingly difficult, if not impossible, for realistic 3-D structures. To overcome these immense issues, this research utilizes dispersive media (Drude or Lorentz models) that can minimize some of the problems (anisotropic, inhomogeneous material parameters) associated with “true” cloaks, but can yield similar cloaking properties. The r...
IEEE Transactions on Power Electronics, 1997
The paper describes a variable speed wind generation system where fuzzy logic principles are used... more The paper describes a variable speed wind generation system where fuzzy logic principles are used for efficiency optimization and performance enhancement control. A squirrel cage induction generator feeds the power to a double-sided pulse width modulated converter system which pumps power to a utility grid or can supply to an autonomous system. The generation system has fuzzy logic control with vector control in the inner loops. A fuzzy controller tracks the generator speed with the wind velocity to extract the maximum power. A second fuzzy controller programs the machine flux for light load efficiency improvement, and a third fuzzy controller gives robust speed control against wind gust and turbine oscillatory torque. The complete control system has been developed, analyzed, and validated by simulation study. Performances have then been evaluated in detail.
IEEE Transactions on Microwave Theory and Techniques, 1982
The thermal response of a human in the near-zone of an antenna was determined by numerical proced... more The thermal response of a human in the near-zone of an antenna was determined by numerical procedures. The approach taken was to modify the heat transfer equations for man in air to account for thermal Ioadkrg due to the energy absorbed from the radiating antenna. The absorbed power density distribution in the human body was determined by considering the body and antenna to be a coupled system in which the resulting system of equations were solved by moment method procedures. This information was then analyzed by a thermal response model consisting of a series of transient conduction equations with internal heat generation due to metabolism, internal convective heat transfer due to blood flow, external interaction by convection and radiation, and cooling of the skin by sweating and evaporation. Internal heating patterns were calculated for two cases a human in the near-zone of a quarter-wave monopole and a half-wave dipole operating at 45 and 200 MHz, respectively. It was found that negligible heating occurred for antennas with input power levels of less than 50 W'.
IEEE Transactions on Microwave Theory and Techniques, 1984
For humans exposed to electromagnetic (EM) radiation, the resulting thermophysiologic response is... more For humans exposed to electromagnetic (EM) radiation, the resulting thermophysiologic response is not well understood. Because it is urdikely that this information will be determined from quantitative experimentation, it is necessary to develop theoretical models which predict the resultant thermat response after exposure to EM fields. Thesecalculations are difficult and involved because the human thermoregulatory system is very complex. In this paper, the important mmrericaf models are reviewed and possibilities for future development are discussed.
IEEE Transactions on Microwave Theory and Techniques, 1986
The rate of the radio-frequency energy deposition in a model of the human body exposed in the nea... more The rate of the radio-frequency energy deposition in a model of the human body exposed in the near-field of a resonant dipole at 350 MHz was calculated using the moment method. Detailed maps of the electric-field intensity in a similar model under the same exposure conditions were obtained using a computer-controlled scanning system and an implantable electric-field probe. A comparison
IEEE Transactions on Microwave Theory and Techniques, 1986
The rate of the radio-frequency energy deposition in a model of the human body exposed in the nea... more The rate of the radio-frequency energy deposition in a model of the human body exposed in the near-field of a resonant dipole at 350 MHz was calculated using the moment method. Detailed maps of the electric-field intensity in a similar model under the same exposure conditions were obtained using a computer-controlled scanning system and an implantable electric-field probe. A comparison
IEEE Transactions on Microwave Theory and Techniques, 1986
The rate of the radio-frequency energy deposition in a model of the human body exposed in the nea... more The rate of the radio-frequency energy deposition in a model of the human body exposed in the near-field of a resonant dipole at 350 MHz was calculated using the moment method. Detailed maps of the electric-field intensity in a similar model under the same exposure conditions were obtained using a computer-controlled scanning system and an implantable electric-field probe. A comparison
IEEE Transactions on Biomedical Engineering, 1987
Bioelectromagnetics
Electromagnetic fields can interact with biological tissue both electrically and mechanically. Th... more Electromagnetic fields can interact with biological tissue both electrically and mechanically. This study investigated the mechanical interaction between brain tissue and an extremely-low-frequency (ELF) electric field by measuring the resultant vibrational amplitude. The exposure cell is a section of X-band waveguide that was modified by the addition of a center conductor to form a small TEM cell within the waveguide structure. The ELF signal is applied to the center conductor of the TEM cell. The applied ELF electric field generates an electrostrictive force on the surface of the brain tissue. This force causes the tissue to vibrate at a frequency equal to twice the frequency of the applied sinusoidal signal. An X-band signal is fed through the waveguide, scattered by the vibrating sample, and detected by a phase-sensitive receiver. Using a time-averaging spectrum analyzer, a vibration sensitivity of approximately 0.2 nmPp can be achieved. The amplitude of the brain tissue vibrational response is constant for vibrational frequencies below 50 Hz; between 50 and 200 Hz resonant phenomena were observed; and above 200 Hz the amplitude fall-off is rapid.
Artificial intelligence techniques, such as fuzzy logic, neural network, and genetic algorithm, a... more Artificial intelligence techniques, such as fuzzy logic, neural network, and genetic algorithm, are recently showing a lot of promise in the application of power electronic systems. The paper describes the control strategy development, design, and experimental performance evaluation of a fuzzy-logicbased variable-speed wind generation system that uses a cagetype induction generator and double-sided pulsewidth-modulated (PWM) converters. The system can feed a utility grid maintaining unity power factor at all conditions or can supply an autonomous load. The fuzzy-logic-based control of the system helps to optimize efficiency and enhance performance. A complete 3.5-kW generation system has been developed, designed, and thoroughly evaluated by laboratory tests, in order to validate the predicted performance improvements. The system gives excellent performance and can easily be translated to a larger size in the field.
IEEE Transactions on Biomedical Engineering, 1989
A finite-difference time-domain technique was used to calculate the specific absorption rate (SAR... more A finite-difference time-domain technique was used to calculate the specific absorption rate (SAR) at various sites in a heterogeneous block model of man. The block model represented a close approximation to a full-scale heterogeneous phantom model. Both models were comprised of a skeleton, brain, lungs, and muscle. Measurements were conducted in the phantom model using an implantable electric-field probe and a computer-controlled data acquisition system. The calculation and measurement of SAR distributions were compared primarily in the head (including the neck) and chest. To obtain the necessary spatial resolution with the computer model, the head and neck were modeled with approximately 105,000 cells, while 86,000 cells were used to configure the chest. Planewave fields, polarized in the E orientation, were utilized to irradiate the models at an exposure frequency of 350 MHz. Reasonable correlation existed between the calculations and measurements.
IEEE Transactions on Biomedical Engineering, 2000
Distributions of the specific absorption rate (SAR) were measured in a full-scale heterogeneous m... more Distributions of the specific absorption rate (SAR) were measured in a full-scale heterogeneous model of man. The model contained a skeleton, brain, lungs, and muscle. All these tissues had dielectric properties close to those of the respective in vivo properties of actual tissues at the test frequencies. SAR's were measured for exposures in the far field at 160, 350, and 915 MHz for the E and H polarizations. A computer-controlled scanning system and an implantable, minimally perturbing electric field probe were used. The results are also compared with the SAR distributions previously measured in a homogeneous model.
IEEE Transactions on Microwave Theory and Techniques, 1986
The rate of the radio-frequency energy deposition in a model of the human body exposed in the nea... more The rate of the radio-frequency energy deposition in a model of the human body exposed in the near-field of a resonant dipole at 350 MHz was calculated using the moment method. Detailed maps of the electric-field intensity in a similar model under the same exposure conditions were obtained using a computer-controlled scanning system and an implantable electric-field probe. A comparison
IEEE Transactions on Biomedical Engineering, 2000
Distributions of the specific absorption rate (SAR) were measured in a full-scale heterogeneous m... more Distributions of the specific absorption rate (SAR) were measured in a full-scale heterogeneous model of man. The model contained a skeleton, brain, lungs, and muscle. All these tissues had dielectric properties close to those of the respective in vivo properties of actual tissues at the test frequencies. SAR's were measured for exposures in the far field at 160, 350, and 915 MHz for the E and H polarizations. A computer-controlled scanning system and an implantable, minimally perturbing electric field probe were used. The results are also compared with the SAR distributions previously measured in a homogeneous model.