Sources Of Electromagnetic Fields Research Articles

Equivalent circuit of external electromagnetic fields coupling to a transmission line above a lossy ground

Based on the vector fitting and the controlled sources in HSPICE, the delay extraction-based passive compact transmission-line (DEPACT) macromodeling for a transmission line above a lossy ground is presented. Combined with the equivalent sources of the external electromagnetic fields, the equivalent circuits about the scatted voltages and total voltages are proposed. The simulation results are compared with the inverse Fourier transform method and good agreement is obtained. At the same time, using this approach, the transient response for a transmission line above a lossy ground with nonlinear terminations excited by the external electromagnetic fields could be obtained easily and accurately.

Retraction of: EUROPAEM EMF Guideline 2015 for the prevention, diagnosis and treatment of EMF-related health problems and illnesses

Chronic diseases and illnesses associated with unspecific symptoms are on the rise. In addition to chronic stress in social and work environments, physical and chemical exposures at home, at work, and during leisure activities are causal or contributing environmental stressors that deserve attention by the general practitioner as well as by all other members of the health care community. It seems certainly necessary now to take "new exposures" like electromagnetic field (EMF) into account. Physicians are increasingly confronted with health problems from unidentified causes. Studies, empirical observations, and patient reports clearly indicate interactions between EMF exposure and health problems. Individual susceptibility and environmental factors are frequently neglected. New wireless technologies and applications have been introduced without any certainty about their health effects, raising new challenges for medicine and society. For instance, the issue of so-called non-thermal effects and potential long-term effects of low-dose exposure were scarcely investigated prior to the introduction of these technologies. Common EMF sources include Wi-Fi access points, routers and clients, cordless and mobile phones including their base stations, Bluetooth devices, ELF magnetic fields from net currents, ELF electric fields from electric lamps and wiring close to the bed and office desk. On the one hand, there is strong evidence that long-term-exposure to certain EMF exposures is a risk factor for diseases such as certain cancers, Alzheimer's disease and male infertility. On the other hand, the emerging electromagnetic hypersensitivity (EHS) is more and more recognized by health authorities, disability administrators and case workers, politicians, as well as courts of law. We recommend treating EHS clinically as part of the group of chronic multisystem illnesses (CMI) leading to a functional impairment (EHS), but still recognizing that the underlying cause remains the environment. In the beginning, EHS symptoms often occur only occasionally, but over time they may increase in frequency and severity. Common EHS symptoms include headaches, concentration difficulties, sleeping problems, depression, lack of energy, fatigue and flu-like symptoms. A comprehensive medical history, which should include all symptoms and their occurrences in spatial and temporal terms and in the context of EMF exposures, is the key to the diagnosis. The EMF exposure can be assessed by asking for typical sources like Wi-Fi access points, routers and clients, cordless and mobile phones and measurements at home and at work. It is very important to take the individual susceptibility into account. The primary method of treatment should mainly focus on the prevention or reduction of EMF exposure, that is, reducing or eliminating all sources of EMF at home and in the workplace. The reduction of EMF exposure should also be extended to public spaces such as schools, hospitals, public transport, and libraries to enable persons with EHS an unhindered use (accessibility measure). If a detrimental EMF exposure is reduced sufficiently, the body has a chance to recover and EHS symptoms will be reduced or even disappear. Many examples have shown that such measures can prove effective. Also the survival rate of children with leukemia depends on ELF magnetic field exposure at home. To increase the effectiveness of the treatment, the broad range of other environmental factors that contribute to the total body burden should also be addressed. Anything that supports a balanced homeostasis will increase a person's resilience against disease and thus against the adverse effects of EMF exposure. There is increasing evidence that EMF exposure has a major impact on the oxidative and nitrosative regulation capacity in affected individuals. This concept also may explain why the level of susceptibility to EMF can change and why the number of symptoms reported in the context of EMF exposures is so large. Based on our current understanding, a treatment approach that minimizes the adverse effects of peroxynitrite - as has been increasingly used in the treatment of multisystem disorders - works best. This EMF Guideline gives an overview of the current knowledge regarding EMF-related health risks and provides concepts for the diagnosis and treatment and accessibility measures of EHS to improve and restore individual health outcomes as well as for the development of strategies for prevention.

The influence of electromagnetic pollution on living organisms: historical trends and forecasting changes.

Current technologies have become a source of omnipresent electromagnetic pollution from generated electromagnetic fields and resulting electromagnetic radiation. In many cases this pollution is much stronger than any natural sources of electromagnetic fields or radiation. The harm caused by this pollution is still open to question since there is no clear and definitive evidence of its negative influence on humans. This is despite the fact that extremely low frequency electromagnetic fields were classified as potentially carcinogenic. For these reasons, in recent decades a significant growth can be observed in scientific research in order to understand the influence of electromagnetic radiation on living organisms. However, for this type of research the appropriate selection of relevant model organisms is of great importance. It should be noted here that the great majority of scientific research papers published in this field concerned various tests performed on mammals, practically neglecting lower organisms. In that context the objective of this paper is to systematise our knowledge in this area, in which the influence of electromagnetic radiation on lower organisms was investigated, including bacteria, E. coli and B. subtilis, nematode, Caenorhabditis elegans, land snail, Helix pomatia, common fruit fly, Drosophila melanogaster, and clawed frog, Xenopus laevis.

The relationship between local field potentials (LFPs) and the electromagnetic fields that give rise to them.

The relationship between local field potentials (LFPs) and the electromagnetic fields that give rise to them.

Relationship between electromagnetic and acoustic emissions in deformed piezoelectric media: Microcracking signals

Simultaneous acoustic (AE) and electromagnetic (EME) emissions during uniaxial compression of polycrystalline natural rocks which behave like brittle ‘isotropic’ piezoelectrics are studied experimentally. The plastic deformation of the brittle rocks is carried out mainly by microcracking which due to piezoelectric properties of the samples is accompanied by generation of electroacoustic waves. Such excitations can be interpreted as polarization currents and, consequently, as sources of electromagnetic fields that can be detected not only within the piezoelectric sample but also in its exterior. As a result, electromagnetic irradiation from deformed sample is accessible to be registered by an external antenna. The corresponding mechanism differs essentially from EME of moving dislocations in ionic crystals. We present the theoretical description of the electroacoustical irradiation during microcracking in isotropic piezoelectric plate. An agreement between theory and experiment has been discussed.

Focal points for improving communications about electromagnetic fields and health: a mental models approach

Central to the precautionary policy is the provision of information about electromagnetic fields (EMF) technology, exposures, potential health risks and exposure management actions to the public. To meet this need at the broadest level, beyond the specific technology foci of previous research, a research project was commissioned as part of Dutch Electromagnetic Fields and Health Research Programme. This study provides an assessment of Dutch EMF information needs from an ensemble of sources by addressing people’s existing ideas and beliefs, using a mental models approach. A summary expert model of influences on and consequences of exposure derived from search of the relevant literature is informed by interviews with 15 scientists and professionals with diverse expertise. Although the professionals characterize the physical characteristics and psychological aspects of exposure to EMF in daily life similarly, there is no consensus regarding potential health effects. Interviews with 12 lay people followed by a confirmatory survey of the general Dutch public (n = 403) reveal not only wide variation in beliefs regarding potential health effects of EMF, but also overestimation of the amount of radiation from public sources relative to personal sources of EMF. People do not feel adequately informed by the government about EMF, and knowledge of government policies on EMF is limited. Together, the evidence suggests three focal points for improving EMF risk communications: providing more clarity regarding the uncertainty of evidence for health effects, illuminating personal EMF exposures in daily life and providing more accessible and transparent information on governmental policies.

Generalized Active EMF Cancel Methods for Wireless Electric Vehicles

In the inductive power transfer systems (IPTSs) of wireless electric vehicles (WEV), the electromagnetic field (EMF) should be lowered for the safety of pedestrians. In general, the EMF should be canceled for every space, time, and load condition of interest. Three generalized design methods for cancelling the EMF of WEV are proposed in this paper. By adding active EMF cancel coils to each primary main coil and secondary main coil, respectively, the EMF generated from each main coil can be independently cancelled by their corresponding cancel coils. Moreover, the EMF can be successfully mitigated if a dominant EMF source only is cancelled with 3-dB margin, which can be applied to any resonant type wireless power transfer systems. Furthermore, no significant power drop may occur if the cancel coils are placed aside from magnetic coupling path. Design examples are shown for U-type and W-type IPTS as well as a wireless stationary EV charger. Experimental verifications are shown for a recently developed I-type IPTS, which has a narrow rail width structure with alternating magnetic polarity along with a roadway. The proposed design methods have been demonstrated, without the loss of generality, to only the secondary coil where relatively large EMF is generated due to high ampere turns. An optimum spacing for cancel coils from main coils and an optimum number of turns are determined. Through experiments, additional EMF mitigation techniques such as the magnetic mirror method, separating pick-up rectifiers, and passive Al plate are provided. Thus, the EMF at 1 m distance from the center of a pick-up becomes under 44 mG even for the maximum power of 12 kW.

A combined method of simulation of an electric circuit and field problems in the theory of induction heating

A combined method for numerical computation of the electromagnetic field in induction-heating systems is proposed and used. The method consists in a combination of methods of integral equations for the computation of the electromagnetic field in the area outside the load and methods of finite elements or finite differences for the computation of the electromagnetic field inside the load. A method of simulation of electrotechnical systems with simultaneous solving of circuit and field problems is proposed based on this method. Using the example of induction-heating devices, an external problem associated with the computation of circuit inductors, power supplies, and balancing capacitors and an internal problem related to the computation of the electromagnetic field and internal heat sources inside the load are formulated. The simulation of induction heaters is considered taking into account features of thyristor frequency converters with a parallel inverter.

Modeling of Electric and Magnetic Fields Around 132 kV Transmission Line

Exposure to natural and manmade extremely low frequency (ELF) electromagnetic fields (EMF) have been a concern during previous years. Schumann Resonance (SR) phenomenon is the source of natural ELF EMFs. High voltage (HV) Transmission Lines is one of the major sources of manmade ELF EMFs. Staying around or close to transmission lines have reported to cause ill effects on human health. The health effects can be analyzed by measuring the external and internal fields. The main objective of this study is to do exposure assessment around HVAC line and model the same using a program developed in MATLAB. A double circuit 132 kV, 50 Hz transmission line was selected for this purpose.ELF EMFs around HV line were measured using a low frequency analyzer ME 3830B. Measured external field levels were modeled using regression analysis, support vector machine (SVM), Neural Network (NN) and Hybrid technique. Finally comparative analysis of all modeling techniques was presented.

A new electromagnetic beacon tool for directional drilling in steam assisted gravity drainage horizontal wells

Steam assisted gravity drainage (SAGD) wells require precise separation between the production well and the injection well to ensure the efficient oil drainage of the reservoir. The precise measurement of the distance and direction between the being drilled injection horizontal well and the cased production horizontal well is needed during the SAGD drilling process. This high accuracy downhole surveying is achieved through the use of active magnetic ranging method. Based on this method, a new electromagnetic beacon tool has been invented with the purpose of simplifying the process of the drilling operation and reducing the cost in SAGD projects. A solenoid has been integrated into the beacon as the electromagnetic field source and an “H bridge” circuit has also been designed for alternating the direction of the current in the solenoid. Besides, a telecommunication circuit was designed and configured in the beacon to receive wireless signal. Deployed as the electromagnetic field source in the cased production well, the beacon can induced electromagnetic field for guiding the directional drilling trajectory along a path parallel to the existing production SAGD horizontal well. The electromagnetic beacon tool has a successful experiment in the “shallow well”. It can guide the directional drilling process in SAGD horizontal wells and make it possible to drill the injection SAGD horizontal well without any access to the production well.

Software Design for Theory Analysis of Underwater Electromagnetic Field in Shallow Sea Environment

The driving sources of the marine environment underwater electromagnetic field are complicated, the environmental parameters working on field source amplitude are numerous. The paper filters out the main respective factor through comparative analysis, on the basis of which composes theoretical analysis software of electromagnetic field underwater and the main environmental factors. The result shows that it is easy to get the variations of field source amplitude and main environmental parameters by setting the main environmental parameter values and field source forms.

0285 Development of a source-based approach to assessing occupational exposure to electromagnetic fields in the INTEROCC study0285 Development of a source-based approach to assessing occupational exposure to electromagnetic fields in the INTEROCC study

ObjectivesExposure to electromagnetic fields (EMF) has become ubiquitous in modern life and concern has increased regarding possible associated health effects. To date, assessment of occupational exposure has relied on job-exposure...

Study of energy parameters of abiotic environment in near-field low-frequency electromagnetic field source zone

One of the tasks of system ecology is the study of changes in the abiotic environment as a result of economic activity. Currently, environmental monitoring of low-frequency electromagnetic fields in the abiotic environment of built-over lands is based on the study of the amplitude spectrum of electric-field and magnetic-field intensities. On the basis of the similarity of wave processes the authors theoretically showed the possibility of intensymmetric approach to monitoring and definition of complex intensity of low-frequency electromagnetic field. The authors presented the theoretical and practical justification of the study of the active component of the integrated intensity of the near-field zone of low-frequency source of electromagnetic influence. Determination of the active component of the intensity will help to find the direction of the radiation source and develop the most effective methods of protection. Besides, the conducting of intensymmetric measurements of low-frequency electromagnetic fields will allow proceeding to the evaluation of the total negative impact on human and natural environment.

Residential proximity to electromagnetic field sources and birth weight: Minimizing residual confounding using multiple imputation and propensity score matching

Studies have suggested that residential exposure to extremely low frequency (50Hz) electromagnetic fields (ELF-EMF) from high voltage cables, overhead power lines, electricity substations or towers are associated with reduced birth weight and may be associated with adverse birth outcomes or even miscarriages. We previously conducted a study of 140,356 singleton live births between 2004 and 2008 in Northwest England, which suggested that close residential proximity (≤50m) to ELF-EMF sources was associated with reduced average birth weight of 212g (95%CI: −395 to −29g) but not with statistically significant increased risks for other adverse perinatal outcomes. However, the cohort was limited by missing data for most potentially confounding variables including maternal smoking during pregnancy, which was only available for a small subgroup, while also residual confounding could not be excluded. This study, using the same cohort, was conducted to minimize the effects of these problems using multiple imputation to address missing data and propensity score matching to minimize residual confounding.Missing data were imputed using multiple imputation using chained equations to generate five datasets. For each dataset 115 exposed women (residing ≤50m from a residential ELF-EMF source) were propensity score matched to 1150 unexposed women. After doubly robust confounder adjustment, close proximity to a residential ELF-EMF source remained associated with a reduction in birth weight of −116g (95% confidence interval: −224:−7g). No effect was found for proximity ≤100m compared to women living further away.These results indicate that although the effect size was about half of the effect previously reported, close maternal residential proximity to sources of ELF-EMF remained associated with suboptimal fetal growth.

A New Approach to Monitoring Low Frequency Electromagnetic Fields

The article contains the analysis of energy characteristics of low frequency electromagnetic fields; shows the relationship between the value and the direction of active and reactive intensity and the borders of near- and far-field zones, and distance to the source of radiation. It also shows in theory the possibility to determine the integrated intensity of the low frequency electromagnetic field. A measuring device was developed, and experiments on examination of the active intensity in the near-field zone of an electromagnetic field source were carried out. The article suggests a new approach to monitoring low frequency electromagnetic fields based on determination of energy characteristics, which will allow to estimate overall spatial distribution of energy, total energy impact, and also to develop the most effective methods of protection.

Improvement of Tungsten Inert Gas (TIG) Welding Penetration Using the Effect of Electromagnetic Field

Tungsten Inert Gas (TIG) welding is a process which an electric arc generated by the tungsten electrode to the workpiece and the welding area protected by a protective gas. Arc shape can be affected by electromagnetic force. In previous study, the use of some electromagnetic field around the arc has influenced the welding results. In this study, electromagnetic field generated from the solenoids was given to the welding arc. Welding process was conducted on Stainless Steel. The electromagnetic field made the arc becomes deflected. This deflection was controlled by the solenoid by activating it using a microcontroller. The results showed that the use of solenoid as a source of electromagnetic field has influenced the welding arc. Penetration produced by using a solenoid has deeper penetration than welding process without using solenoid. The increase of the welding power efficiency was 10.9% for arc current I = 80 A and 9.85% for arc current I = 90 A.

Longterm Electromagnetic Field Measurements and Pollution Maps in a University Campus

Electric field intensity emitted by electromagnetic field sources of the base stations in the campus of Inonu University and other very high frequency electromagnetic field sources' spread which are effect above at campus field were done and the frequency-based electromagnetic intensity maps of the campus were prepared. According to achieved measurement conclusions, the results were evalauted by comparing the periodical changes. The field intensity values of the electromagnetic waves which have different frequencies were measured by making a spectrum analysis over 450 points in the range of 27MHz-3GHz frequency in 2011. Also, in 2013, electric field intensity values were measured with instant measurements over 6700 points in the range of 100kHz-8GHz frequency. The electromagnetic pollution maps were drawn with obtained electric field values and the results were evaluated. One of study aims, it was determined changing electric field intensity along two-year period in campus of university. Another one purpose is provided homogeneous distribution of electric field source at this area with electromagnetic pollution maps which are drawn by obtained datas from results of measurements, and determined possible risk areas.

Histopathological examination of glomerulus in the kidney of newborn rats following prenatal exposure to 900 MHz electromagnetic field

Widespread use of mobile phones, which are a major source of electromagnetic fields (EMF), might affect living organisms. It has been known that exposure to EMF has side effects on animal tissue and their physiological activities. The use of mobile phones is currently one of the fastest growing technological developments. The close proximity of the antenna of such a device to the abdominal organs has raised concerns about the biological interactions between EMF and the kidney. The kidney is a major potential route for the absorption of hazardous materials encountered in the environment. The mobile telephone emitting 900 MHz radiations may be absorbed by kidney more than other internal organs because mobile phones are often carried in belts. Additionally; the direct biological effects of exposure to 900-MHz EMF have not been studied extensively. For that reasons, we aimed to study the effect of prenatal exposure to 900 MHz EMF on the glomeruli in the kidney of the 4-week male rats. Pregnant rats were randomly divided into two groups that are the control (Cont) and the electromagnetic fields exposure (EMF) groups (three pregnant rats each group). Pregnant rats in the Cont group were kept under the standard laboratory conditions and the pregnant rats of EMF group were exposed to an EMF of 900 MHz for 60 min/day from the first to the last day of the gestation period. The exposure period was from 12.00 p.m. to 13.00 p.m. each day. Fourteen pups were obtained from control pregnant rats (4, 5 and 5 pups from Cont 1, 2 and 3 pregnant rats, respectively) and the 15 pups were obtained EMF exposed pregnant rats (4, 5 and 6 pups from EMF 1, 2 and 3 pregnant rats, respectively) after spontaneous delivery. At the end of the 4th week, totally 11 pups were randomly selected for study without regarding their sexes. They were divided into the Cont group (n=5), obtained randomly from the pregnant rats of the control group, and the EMF group (n=6), obtained randomly from the pregnant rats of the EMF group. At the end of 4 weeks, offspring were anesthetized with urethane and removed kidneys were routinely processed and cut into serial sections at 10μm thickness, stereological and histopathological analyses were done. According to statistical analysis there were significant differences between the Cont and EMF groups in terms of numerical density of glomeruli. As a result of the study, we suggest that 900 MHz EMF may cause a decrease in the glomerular density in the rat kidney.

Recent microwave research studies of Gazi Biophysics & Gazi Non-Ionizing Radiation Protection Center

Recent microwave research studies of Gazi Biophysics & Gazi Non-Ionizing Radiation Protection Center

Electromagnetic Interference With Implantable Cardioverter-Defibrillators at Power Frequency

The number of implantable cardioverter-defibrillators (ICDs) for the prevention of sudden cardiac death is continuing to increase. Given the technological complexity of ICDs, it is of critical importance to identify and control possible harmful electromagnetic interferences between various sources of electromagnetic fields and ICDs in daily life and occupational environments. Interference thresholds of 110 ICD patients (1-, 2-, and 3-chamber ICDs) were evaluated in a specifically developed test site. Patients were exposed to single and combined electric and magnetic 50-Hz fields with strengths of up to 30 kV·m⁻¹ and 2.55 mT. Tests were conducted considering worst-case conditions, including maximum sensitivity of the device or full inspiration. With devices being programmed to nominal sensitivity, ICDs remained unaffected in 91 patients (83%). Five of 110 devices (5%) showed transient loss of accurate right ventricular sensing, whereas 14 of 31 (45%) of the 2- and 3-chamber devices displayed impaired right atrial sensing. No interference was detected in 71 patients (65%) within the tested limits with programming to maximum sensitivity, whereas 20 of 110 subjects (18%) exhibited right ventricular disturbances and 19 of 31 (61%) subjects exhibited right atrial disturbances. Extremely low-frequency daily-life electromagnetic fields do not disturb sensing capabilities of ICDs. However, strong 50-Hz electromagnetic fields, present in certain occupational environments, may cause inappropriate sensing, potentially leading to false detection of atrial/ventricular arrhythmic events. When the right atrial/right ventricular interferences are compared, the atrial lead is more susceptible to electromagnetic fields. http://clinicaltrials.gov/ct2/show/NCT01626261. Unique identifier: NCT01626261.