Comparative Determinations of Magnetic Induction in AC and DC Circuits

In this paper, the problems of calculating and solution about electromagnetic fields were studied. In the circumstances of the static electromagnetic field that is limited and differentiable on a symmetric axis, it provides a new theory and technique and method on measurement axial symmetric and passive and static electromagnetic field by making use of the Maxwell’s equations and calculus. Out-of-axis electromagnetic field can be transformed into series by means of the method. The series include the electromagnetic field on the symmetric axis and its all order derivative. Applying the method is very easy, quick and exact to perform numerical calculation. For the authors provide series form, we need to prove that it meets the Maxwell’s equations. This paper provided the strict proof by means of series and calculus operation. Therefore, the theory, method and results given by this paper are not only certain theoretical meaning, but also quite great-applied value.

The European Directive 2013/35/EU was implemented into German legislation by the EMF Ordinance in 2016. To improve the comprehensibility and usability of the EMF Ordinance, Technical Rules are currently being developed to assist employers, particularly in small and medium sized enterprises, to implement state of the art of occupational safety and health measures. By applying the information and measures contained in the Technical Rules, compliance with the EMF Ordinance is ensured Action Levels or Exposure Limit Values are used to assess risks associated with exposure to electromagnetic fields at workplaces. When comparing risk assessments based on Exposure Limit Values against those based in Action Levels, it is rather challenging to assess measured or calculated exposure values against Exposure Limit Values. Besides detailed information on risk assessment of electromagnetic fields at workplaces, Technical Rules provide employers with thorough instructions on how to apply Exposure Limit Values when assessing risks arising from electromagnetic fields providing a simple and guided approach to fulfil the requirements of the EMF Ordinance. When reflecting this from an international perspective, in the facet of applying Exposure Limit Values for EMF risk assessment, EN 50499 will be well complemented by the open access Technical Rules for the German EMF Ordinance.

A precise estimation of stray losses in skewed rotor induction motors is an important and yet very challenging topic for machine designers. Methods for evaluating the stray losses in skewed rotor induction motors by coupling a 2-D multi-slice lime stepping fiiiHe element model into a 3-D time stepping finite element method are presented in this paper. The model can take into account the inter-har currents which are ignored if a 2-D finite element model only is used. New formulas, which are based on the actual changes in the magnetic flux densities and can be easily coupled into a time stepping finite element method for estimating the iron losses, are also described.

Gravitational waves (GWs) from astrophysical sources can interact with background electromagnetic fields, giving rise to distinctive and potentially detectable electromagnetic signatures. In this paper, we study such interactions for far-field gravitational radiation using the 1 + 3 approach to relativity. Linearized equations for the electromagnetic field on perturbed Minkowski space are derived and solved analytically. The inverse Gertsenshteĭn conversion of GWs in a static electromagnetic field is rederived, and the resultant electromagnetic radiation is shown to be significant for highly magnetized pulsars in compact binary systems. We also obtain a variety of nonlinear interference effects for interacting gravitational and electromagnetic waves, although wave–wave resonances previously described in the literature are absent when the electric–magnetic self-interaction is taken into account. The fluctuation and amplification of electromagnetic energy flux as the GW strength increases towards the gravitational–electromagnetic frequency ratio is a possible signature of gravitational radiation from extended astrophysical sources.

To measure the potential impact on clinical MRI practice in the UK of the European Union (EU) Physical Agents Directive (PAD) on electromagnetic fields (EMF). There is evidence that the exposure limit values contained in the PAD will make it impossible for members of staff to stand close to the magnet during scanning; currently this is common practice in order to provide care and support for vulnerable patients. Interventional MR procedures will also be impossible. Members of the British Association of MR Radiographers (BAMRR) were sent a questionnaire to assess the impact of the PAD and related safety issues. A total of 25% of responding sites have at least one sedation/general anesthesia (GA) session per week, while only 3% reported any interventional practice. A total of 29% of respondents reported that operators give a bolus injection by hand during contrast-enhanced magnetic resonance angiography (CE-MRA) scans. Overall it is estimated that 3% of all MR examinations in the UK are performed with a staff member in the magnet room. Some of these examinations would be impossible without staff in the room and it would be necessary for patients to have computed tomography (CT) instead of MRI. The additional radiation dose of substituting CT for MRI is estimated at 224 man-sievert per year. While the financial costs of implementing the PAD (EMF) are relatively low, the social costs are difficult to quantify but potentially more alarming.

10.03 - Bioelectromagnetism in the Living Body

Electromagnetic fields are known to affect the bone metabolism by modifying some relevant physiologic cell parameters of cells, even though the underlying mechanisms are still unclear. The aim of our study was to evaluate the effect of both static magnetic fields (SMFs) of the same intensity of the one generated by spinal metal devices and pulsed electromagnetic fields (PEMFs) of the same intensity used for the management of nonunion on human osteoclasts cell culture. Primary osteoclast cells were isolated from primary human osteoclast precursors and were exposed to SMFs and to PEMFs. Morphology and tartrate-resistant acid phosphatase (TRAP) activity were evaluated in the osteoclast cultures after 7, 10, and 14 days of exposure. The SMF-exposed cells show a more differentiated phenotype and a significantly higher TRAP activity after 7 and 10 days of treatment with respect to a sham control. PEMF-exposed cells have a less-differentiated phenotype after 7 days of exposure compared with the relative sham control, while the TRAP activity shows no statistically significant differences between exposed and control cells at any observation time. Our results indicate that SMFs of the same intensity of the one generated around spinal devices can affect osteoclast differentiation and activity. Aseptic loosening around titanium implants might be due in part to an increased osteoclast activity and differentiation. PEMFs of the same intensity than the one used for the management of nonunions can affect osteoclasts phenotype after 7 days of exposure, while osteoclasts TRAP activity is not affected by this kind of electromagnetic fields.

The canonical theory of motion of a charged particle in a slowly varying, static electromagnetic field is formulated. The hamiltonian is written down explicitly in terms of the coordinates of the gyration and the drift. The method of approach is analogous to that of the canonical formalism with subsidiary condition as used in theories of collective motion in many-body systems, such as the motion of the center of gravity. In the lowest order of the perturbation, it is shown that the hamiltenian for the drift motion averaged over the gyration phase is given by adding to the original hamiltonian a potential term equal to the product of the magnetic moment and the magnetic field strength. (D.L.C.)

This study evaluates the radiation safety implications of electromagnetic field (EMF) from electrical distribution sub-stations in Aguata Local Government Area (LGA), Anambra State, Nigeria, using the EMF meter with a laser distance meter in-situ. Ten (10) locations of 11KV distribution sub-stations were mapped out and used for the study. The results of the in-situ measurement of Electric Field (E) and Magnetic Field (H) were used to evaluate the Power Density (S), Specific Absorption Rate (SAR) and Statistical analysis which includes descriptive statistics, inferential statistical tests (T-test) and graphical analysis to evaluate significant differences of EMF levels between different locations. The EMF emitted by these distribution substations was examined using data from the various locations. The results obtained show that EEDC Office has the highest electric field of 0.6633 V/m, while Oko Road has the second highest of 0.7783 V/m. The magnetic field intensity varies across locations, with Oko Road having the largest of 1.3317 A/m. Power density varied, with Oko Road having the highest 1.0365 W/m2 and Stadium having the lowest 0.1011 W/m2. The Specific Absorption Rate (SAR) ranging from 0.0001 to 0.0005 W/Kg showed consistent rates across locations. The International Commission on Non-Protection of Electromagnetic Fields (ICNIRP) sets EMF exposure regulations from 0-300 GHz at the exposure values of, E = 10,000V/m, H = 4×104 A/m, S = 50W/m2, SAR = 10W/kg. In this study, electric field, magnetic field, power density, and specific absorption rate (SAR) values varied widely between stations, with the magnetic field accounting for 45.25% of total electromagnetic exposure. The exposure to EMF emanating from distribution substations in Aguata LGA does not pose any health effect or any health hazards to the general public comparing the measured data with the standard guideline of ICNIRP.

Introduction Increasing world population is facing critically depletion of water resources, which will be along with increasing food demands to cover the human needs all over the world. Therefore, water scarcity is increasingly a major limitation for increased agricultural production and food security in this century. The scarcity of qualified water, has made farmers to consider the water of marginal quality for usage in agriculture. The Water’s molecular structure is affected by a magnetic field, so that a change in the water relations can affect the overall plant growth. One of the approaches that provides higher productivity and quality assurance is using static electromagnetic fields. The use of magnetically treated water for irrigation in agriculture is considered as one of the important environmental clean methods. The water treated in the magnetic field or pass through a magnetic device called magnetized water. The influence of magnetic field on various growth processes of plants such as seed germination, seedling growth, plant growth, yield and the properties of crop quality have been the object of several researches. Salinity is defined as the presence of excessive concentration of soluble salts in the soil or in the irrigation water that suppresses plant growth and eventually yield. Salt stress has been identified as one of the most serious environmental factors limiting the productivity of crop plants. The deleterious effects of salinity on plant growth are associated with 1) low osmotic potential, 2) nutritional imbalance, 3) specific ion effect, or 4) a combination of these factors. In addition, there is evidence that salt stress can induce oxidative stress due to generation of reactive oxygen species. Phaseolus vulgaris is an annual growing to 2 m height and is frost tender. Bean leaves are trifoliate (three-leaved), arranged in an alternate fashion on the stem and have oval or diamond-shaped leaflets. Leaf color can be green. The study was undertaken to evaluate the use of magnetically treated water in improving seed germination and early seedling growth (i.e., radical and plumule growth) of the bean (Phaseolus vulgaris L.) in the presence and absence of salt stress. The work was carried out at the germination stage because germination is known as a key process that allows the seed embryo to grow and evolve into photosynthetic organism, and it is also a critical stage for plant response to salinity. Materials and Methods In order to investigate the influence of magnetized water and salinity on germination characteristics and seedling of bean (Derakhshan variety), an experiment was conducted based on complete randomized design in factorial arrangement with four replications at laboratory of the Agricultural College of Ferdowsi University of Mashhad in 2014. Water types consisted of two levels (magnetized water and tap water) and five salinity levels: 0, 4, 6.5, 8.5 and 9.5 ds/m. The following indices were also measured: Final Germination Percentage (FGP) and Germination Rate (GR) was calculate base on the below equation FGP= (n / N) × 100 where n is the number of seed germination in per day and N is total number of seeds GR= where giis the number of seed germination in every count and di is the number of days till day n th. (Dere and et al., 1998) Chlorophyll concentration was calculated using the following formula Chla (μg/ml) =15.65 A666 - 7.340 A653 Chlb (μg/ml) =27.05 A653 - 11.21 A666 Cx+c=1000A470 – 2.270 Cha – 81.4Chb/227 Traits as length and dry weight of plumule and radical, biomass and seed vigor index were measured too. Data was analyzed using MSTAT-C software and means were compared using Dunkan multiple range test in 5 percent probability. Results and Discussion The results showed that germination percentage, mean germination time, length and dry weight of the plumule and radical, biomass and seed vigor index decreased with increasing salinity, but magnetized water improved them. Magnetic water increased germination by 6% and reduced the mean germination time by 8%. Magnetized water improved biomass and seed vigor by 52 and 24 percent, respectively. Using magnetic water, improved radical length and plumule by 27 and 24 percentage, respectively. The simple effect of magnetized water and salinity caused significant amounts of chlorophyll a and b and carotenoid. Application of magnetic water increased chlorophyll a (12%) in the salinity level of zero compared with non-magnetic. So that magnetized water improved amount of chlorophyll a and increased carotenoid under salinity conditions. Other results showed that plant cells treated with magnetic represent magnetic properties of atoms placed in them and activates them later on. Conclusion Overall, results showed that exposure to magnetic fields and irrigation water with different salinity levels, decreased salinity (NaCl) effects on bean, accelerated germination and seedling growth and had an important role in improving the beans germination rate.

There are many attempts to increase the germination rate of basidiospores using temperature, light or chemicals. The current study has been designed to use the magnetic and electromagnetic fields to stimulate the germination of basidiospores from Ganoderma applanatum. Mature, healthy and fresh basidiocarpe of Ganoderma applanatum (Aphyllophorales: hymenochaetaceae), causes white rot of hard wood was isolated from Alsantah city (Delta Nile region of Egypt) in autumn 2018 from Casuarina tree. Basidiospores were collected from the fruiting body and cultivated on different microbial growing media. Basidiospores were obtained and exposed to magnetic field (MF) and electromagnetic field (EMF) for different times of exposure extended for one hour. Basidiospores germination was stimulated when exposed to both fields. The electromagnetic field was more stimulating than the magnetic field in basidiospores germination where the spore’s germination rate reached 18.7% after exposure to the electromagnetic field for 40 min while the germination rate was 14.6% after exposure to magnetic field for 50 min. The fruiting body of the fungus was cultured to obtain fungal mycelium, and the resulting mycelium was exposed to the magnetic and electromagnetic field for different exposure times. The resulting mycelia was used to inoculate five different lignocellulosic substrate (Rice straw, Wheat straw, Wheat bran, Rice bran and Sawdust) using solid state fermentation in order to test its efficiency in these wastes degradation. Furthermore, Lignin degrading enzymes including (Laccase, Manganese-dependent peroxidases and Lignin peroxidase) were measured. The three tested enzymes showed a marked increase in their activity after exposure to the magnetic field for 20 minutes (laccase 17.8-unit, lignin peroxidase 11.1-unit and Mn dependent peroxidase 13.5- unit). Concerning the effect of electromagnetic field the activity of lignin degrading enzymes were enhanced after exposure to the electromagnetic field for 20 minutes (laccase 19.5- unit, lignin peroxidase 15.1-unit and Mn dependent peroxidase 27.4-unit). Therefore, the obtained data suggest that the using of both magnetic and electromagnetic fields could be used to break down the dormancy state of the basidiospores in order to increase the rate of spores germination and at the same time increase the activity of lignin degrading enzymes.

Extremely Low Frequency (ELF) Electromagnetic Fields due to low and medium voltages are normally low. But with the wide spread and increase in the use of electrical energy, the potential for exposure has increased considerably. The current research has focused on potential health effects of magnetic fields because some epidemiological studies have suggested an increased cancer risk associated with estimated time of magnetic field exposure. Since the wavelength of ELF electric and magnetic field is sufficiently greater than the dimensions of the biological object, so the electric and magnetic fields can be independently treated. Our main topic in this research is to investigate the effect of magnetic field at power frequency and analyse of the interaction between these fields and the living organisms. We used the measured results and the applied the three techniques of simulating the induced currents in the human body by using a Matlab program. The obtained results can demonstrate the degree of danger due to the induced currents from both magnetic and electric fields. Comparing these results by the values given by International Committee on Non-Ionizing Radiation Protection (ICNIRP) guidelines can tell the degree of danger.

Electromagnetic Environment Associated with Lightning Strikes to Tall Strike Objects

This article reports the outcome of a study commissioned by the Radiation Safety Unit, Government of Saskatchewan, which addressed the public concern on exposure to low-frequency electromagnetic fields (EMF) surrounding power lines. Measurements of EMF are reported for 14.4 to 230 IcV power lines utilizing a model HI-3600-02 extreme low frequency (ELF) power frequency EMF survey meter. Field intensities were within the Canadian standards, with the recorded value for a 230 kV/ 230 kV line voltage yielding a maximum electric field of 1,790 / m at 15 feet from the center and a maximum magnetic field intensity of 2,376 / m at 25 feet from the center. Continued research and analysis are required in determining the mechanism of interaction between EMFs and the human body and to determine if there exists a correlation between EMF exposure and health. Keywords: electromagnetic field intensitylow frequencypower lines

From 2013 to 2018, in-situ measurements of radiofrequency (RF) electromagnetic fields (EMF) and extremely low-frequency (ELF) electric and magnetic fields in 317 existing and under-construction children's playground facilities, in 16 municipalities all over Greece, were carried out by the Greek Atomic Energy Commission (EEAE). These measurements were conducted following legislative framework established in 2009, which requires that compliance with the established exposure limits for EMFs should be verified in playground areas. The results are presented by the value of the electric field (E) and exposure ratio (Λ) for the RF EMF, as well as the value of the electric field (E) and magnetic flux density (B) for the ELF electric and magnetic fields. Statistical analysis tools were applied on measurement data and conclusions have been made, taking into consideration: (i) environment type (urban/suburban), and (ii) vicinity to any transmitting installations. Measurement results correspond to the typical EMF background levels for each environment type. Concerning the environment type, RF EMF, and ELF electric/magnetic field measurements reveal no differentiation between urban and suburban environments. Bioelectromagnetics. 2019;40:602-605. © 2019 Bioelectromagnetics Society.