Sources Of Electromagnetic Fields Research Articles

Momentum and angular momentum reciprocity theorems for acoustic fields.

As a universal theorem applicable to linear physical systems, reciprocity theorems describe the reciprocity between the input and output of linear systems. As for the electromagnetic field, there have been detailed studies on the reciprocity theorems of energy, momentum, and angular momentum, which reveal the correlation between two electromagnetic field sources from different aspects. Based on the fundamentals of linear acoustic theory, the momentum-based and angular momentum-based reciprocity theorems for acoustic fields are derived. They indicate the correlation between two acoustic systems from the perspective of momentum and angular momentum, respectively. On this basis, a systematic summary and analogical study is also performed on various reciprocity theorems for acoustic and electromagnetic fields, which deepens our understanding of the reciprocity theorem as a universal law for linear physical fields. The results obtained in this work can further improve the reciprocity theory of linear acoustic systems, as well as provide theoretical guidance for practical applications, such as audio signal processing and acoustic measurement.

The exposure analysis of the long-term broadband EMF monitoring in the campus area of the University of Novi Sad.

Due to wide prevalence of electromagnetic field (EMF) sources in human surrounding, EMF-level measurements and corresponding exposure assessment have imposed as an important topic. With an intention to present an approach to the long-term exposure assessment in EMF RATEL network, this paper conveys a high-level statistical analysis of the high-frequency exposure data, acquired during the 5-y time period, for the case study of monitoring sensor installed in the area of the Novi Sad University campus. Time series of exposure values were averaged on a daily, weekly, and monthly basis, and their yearly comparison was performed. Results showed clear differences between the day and night hours, as well between working and weekend days. Regarding exposure values, averaged on the monthly basis, the impact of COVID-19 pandemic in 2020 and 2021 can be noticed. Finally, the highest obtained exposure values (electric field squared) were 22 times below the maximal allowable level, according to the Serbian legislation.

USE OF AUGMENTED REALITY IN THE SAFETY OF OPERATING ELECTRIC CAR NEAR CHARGING STATIONS

Augmented reality (AR) provides possibilities from simple displays to tools improving service in the production process. It has found justification in the field of crisis/critical situation management and also in the commercial sphere. The technologies of the digital world together with AR are directed towards the user environment and the operation of technical devices does not deal with the essence of the problem. Electric vehicle (EV) charging stations (CHS) are considered to be sources of electromagnetic fields, as are also inverters in EVs. Until now, there are standards only for stable sources, which EV is not. There are several standards for CHS, from guidelines to regulations in a specific country. The magnetic field (MF), as a component of the electromagnetic field, carries information about the state of the CHS and the environment around the EV during its charging. Information provided to the operator about the state of the environment around him when charging EV is currently at a minimal level. There is no application yet that provides a display of MF information for the operator. AR in the form of the AR Infinity platform provides such an option. The article points out the way of creating information tools using simple devices in an AR environment with a mobile phone application.

Electrical Activity of Heart During ECG For EMF And Non– EMF Trails.

Background: The ubiquitous use of mobile phones has raised concerns about potential health impacts, particularly regarding the effects of electromagnetic fields (EMF) on the human brain and heart. Heart rate variability (HRV) is a critical measure of heart health, influenced by brain function and susceptible to disruption by mobile phone radiation. Objective: This study aims to investigate the influence of mobile phone EMF on HRV, utilizing higher-order spectral analysis of ECG data to determine the functional relationship between the heart and brain under EMF exposure. Methods: Twenty healthy subjects from the University of Sindh, Jamshoro, participated in this experiment. The subjects, with an average age of 27 years, underwent ECG and EEG recording under varying conditions of EMF exposure. Each session involved comparisons of EMF effects over different durations and positions relative to the heart. Results: Statistically significant differences were observed in bicoherence values for chest positions V1 and V2, with non-EMF trials showing higher values compared to EMF trials. Coherence between ECG and EEG indicated significant changes in the 16-30 Hz frequency band during EMF exposure. Extended exposure of 40 minutes correlated with notable variations in HRV. Conclusion: The findings suggest that mobile phone EMF can significantly affect HRV parameters, particularly with prolonged exposure and when the EMF source is close to the heart. These results underscore the importance of developing guidelines for safe mobile phone usage.

Photons in Physics with real Magnetic Charges and the Falsity Existing Notion of Expansion Universe (How Physicists; "Yawn" Real Magnetic Charges, Curved Space and Sentenced the Universe to Expansion)

The experiments of F. Ehrenhaft as well as the experimental and theoretical studies of the author showed that it is magnetic charges are the direct sources of the magnetic field. Eddy currents of magnetic charges (rotating magnetic dipoles g- - g+) which actually exist in atoms and substance, are untwisted by electric current in conductors, are direct sources of the well-known vortex magnetic field rotH. Together with electric charges, magnetic charges make up the shells of atoms, which are actually electromagnetic, not electronic. It is the electromagnetic shells of atoms that are the sources of the vortex electromagnetic (gravitational) field, which is described by the vortex vector rot[E – H]. The vector character of GF is in many respects similar to the vortex magnetic field, which has been known for hundreds of years, but no one has come up with the version of spatial magnetic waves. Therefore, the notion of gravitational waves, according to the author, is another fake, inspired by crooked physics, in which there is absolutely no representation of the real physics of the gravitational field. The introduction of real magnetic charges into the basic physical representations, as well as the discovery by the author of the World Physical Triad, made it possible to clarify the essence of spinor fields which are flows of elementary particles of the world Energo-medium, which are formed by spinor (charged) particles. In addition, the article proves that the concept of the expansion of the Universe was the result of E. Hubble's erroneous (extremely superficial) perception, back in 1929, of the manifestation of the cosmological redshift of the photon frequency, which he interpreted as a Doppler shift in the frequency of the so-called light waves. The inclusion of real magnetic charges in the physical representations showed that the frequency processes in photons are determined exclusively by the intra-photon physics embedded in into at the moment of formation and cannot be the result of any spatial wave formations in the environment, i.e. the shifts of photonic frequency ∆ω have nothing to do with the Doppler effect and depend only on changes in the translational velocity of their source. In other words, the redshift of the photon frequency under the conditions of the translational motion of their sources is exactly the same, both in the case of the source moving to the observer, and in the case of its movement at the same speed away from the observer. As for the violet shift of the photon frequency, this is an unambiguous sign of the rotational dynamics of photon source, and in the case of combined motion of source (translational and rotational), the mechanism of photon frequency pulsations is possible.

Расчетная модель эффективности защиты электромагнитного поля (на примере рабочего места поездного диспетчера)

The article addresses the growing concern over the adverse health effects of electromagnetic radiation in workplaces, particularly in the context of train dispatchers who are exposed to various sources of electromagnetic fields. A computational model is developed to assess the effectiveness of shielding equipment in mitigating the impact of electromagnetic fields on train dispatchers. The study focuses on the design and evaluation of protective casings and shields to reduce electromagnetic field intensity, providing valuable insights for enhancing workplace safety.

A high‐power electromagnetic source for disabling improvised explosive devices

AbstractUltra‐wideband (UWB) microwave sources driven by specialised pulsed power generators have experienced a considerable development in the last decade due to their wide domain of new applications such as defence or counter‐terrorism activity. The authors present the main findings of a research dedicated to the development of a pulsed power‐driven electromagnetic field source for disabling improvised explosive devices (IED). The pulsed power generator driving the source is a 13‐stage compact Marx producing voltage pulses reaching an amplitude of 0.5 MV, with a pulse repetition frequency (PRF) of up to 100 Hz. The generator is coupled to a bipolar pulse forming line, providing bipolar pulses with a dV/dt of around 1.6 MV/ns. This pulsed power system feeds an array composed of 16 Koshelev‐type UWB antennas through an impedance matching transformer. The resulting electromagnetic source is capable to produce pulsed electric fields (PEFs) having a figure‐of‐merit (FOM) of 1 MV. First, practical experiments were carried out to study the effects of the PEFs on targets. The targets used in the present study are M2B type flashbulbs, known to have the same susceptibility as the US army M6 detonator. Different configurations of wires (shielded, twisted, etc) with different lengths were used in connecting items inside these targets. The tests were performed by placing the flashbulbs at different distances to determine the essential parameters (i.e., amplitude, duration, and frequency range) of the PEFs required to trigger them. An overview of the experimental campaign and the main findings are also presented followed by conclusions.

The Mobile Phone Electromagnetic Radiation Effects on Heart Rate Variability Function

Background: The proliferation of mobile phone usage has given rise to concerns about the potential health effects of electromagnetic fields (EMF), particularly in relation to heart rate variability (HRV), a key indicator of cardiac health. Previous studies have yielded inconsistent results using lower-order statistical measures, leaving a gap in understanding the nonlinear interactions between EMF exposure and HRV. Objective: This study aimed to investigate the effects of mobile phone EMF on HRV by employing bicoherence analysis of ECG data. It sought to determine whether the position of EMF exposure relative to the heart and the duration of exposure affected HRV parameters. Methods: Twenty subjects were recruited for the study, with ECG and EEG data collected under EMF and non-EMF conditions. ECG data were captured using a 12-lead system, with electrodes placed according to standard guidelines. EEG electrodes were positioned following the 10-20 system. Bicoherence and coherence analyses were conducted to assess nonlinear interactions in HRV activity and the relationship between heart and brain signals. The study also considered the duration of EMF exposure, comparing the effects of 10-minute and 40-minute sessions. Results: The bicoherence values for ECG data during EMF exposure at the left ear showed negligible differences, with values ranging between 0.0 to 0.04. However, chest positions V1 and V2 revealed statistically significant larger bicoherence values during non-EMF trials as opposed to EMF trials. Coherence analysis between ECG and EEG demonstrated significantly higher values across the 16-30Hz frequency band during EMF trials. No significant differences were observed for 10-minute EMF exposure, whereas 40-minute exposure sessions indicated a correlation with changes in HRV. Conclusion: The study's findings suggest that mobile phone EMF can affect HRV parameters, with the effects being more pronounced during longer exposure durations and when the source of EMF is closer to the heart. These results support the need for guidelines on safe mobile phone usage and further research into the effects of EMF on cardiac function.

Role of electromagnetic energy and momentum in the Aharonov–Bohm effect

We analyse the physical meaning of the Aharonov–Bohm (AB) phase based on its representation through electromagnetic (EM) potentials as a sum of four components, which, in addition to the known electric and magnetic phase components, contains two more terms recently disclosed by our team in the analysis of quantum phase effects for dipoles and charges, and which we named the complementary electric AB phase and the complementary magnetic AB phase. Using the complete expression for the AB phase, we reveal that the phase component, explicitly depending on time, is determined by the interactional electric energy, while the phase component, explicitly depending on the velocity of charge, is determined by the interactional EM momentum for an isolated system ‘source of EM field and charge’. These findings shed new light on the origin of the AB phase and, in particular, allow us to generalize the de Broglie relationship and the Heisenberg uncertainty relations for a charged particle in an EM field.

Investigation of the neuroprotective effect of crocin against electromagnetic field-induced cerebellar damage in male Balb/c mice.

Mobile devices are sources of electromagnetic fields (EMFs) that cause increasing concern among scientists about human health, especially with the long-term use of mobile phones. With regard to this issue, the potential adverse health effects, particularly on brain function have raised public concern. There is considerable evidence that natural compounds have neuro-protective effects due to their antioxidant and anti-inflammatory properties. Growing evidence suggests that crocin as a natural bioactive compound can be considered a potential therapeutic agent against various neurologic disorders. Therefore, the present study investigated the effects of crocin on the cerebellum after exposure to EMF. Twenty-four Male Balb/c mice were divided into control group, EMF group (2100 MHZ), EMF +Crocin group (2100 MHZ+50 mg/kg), and crocin group (50 mg/kg). The animals in the EMF and EMF+Crocin groups were exposed continuously for 30 days to an EMF 120 min/day. After 30 days, cerebellar cortex was evaluated by histomorphometric and immunohistochemical methods. The results showed that 30 days of exposure to EMF had no significant effect on Purkinje cell size. However, EMF reduced significantly the diameter of astrocytes and increased Glial fibrillary acidic protein (GFAP) expression compared to the controls (p<0.05). Our findings also indicated that crocin treatment could improve the diameter of astrocytes and normalize GFAP expression (p<0.05). This study concluded that 2100-MHz EMF caused adverse effects on the cerebellum through astrocyte damage and crocin could partially reverse the EMF-related adverse effects.

Simulation of dust grain charging under hypervelocity impact plasma environment

Dust plasma readily forms during hypervelocity impact, which serves as a source of plasma macroscopic charge separation and strong electromagnetic fields. In this study, we examine the dynamic evolution of surface charging of aluminum dust grains with micrometer or submicrometer sizes in a hypervelocity impact plasma environment based on the theory of orbital motion limited. As dust grains traverse the expanding plasma, plasma density and temperature decrease with increasing distance from the impact point. This leads to longer relaxation times for charging equilibrium (ranging from picoseconds to microseconds) and reduced equilibrium charges. The model incorporates thermionic and secondary electron emission effects on dust grain charging processes while also examining the impacts of five heating and cooling mechanisms on the thermal equilibrium temperatures of dust grains. Near the impact point, thermal equilibrium temperatures exceed aluminum's boiling point, which results in phase transition ablation processes. As dust grain temperatures increase, thermionic emission currents may dominate charging dynamics and influence final equilibrium charge numbers. High-temperature dust grains tend to acquire positive charges. Moreover, we observe that the radius of dust grains considerably affects charging processes, and smaller grain radii correspond to low equilibrium charges and longer relaxation times.

INFLUENCE OF THE ARC WELDING RELATED ELECTROMAGNETIC FIELD ON PACEMAKERS

The patients with implanted pacemaker or cardioverter-defibrillator are exposed to a certain risk of affecting this device by surrounding electromagnetic field. There are many sources of potential risky electromagnetic fields, arc welding is definitely one of them. The aim of this article is to present research focused on analysis of the pacemaker function during welding. There were performed in-vitro measurements with 9 pacemakers during metal inert gas (MIG) and tungsten inert gas (TIG) method arc welding. The responses of pacemakers were monitored by communication via programmer. Based on these measurements there are proposed safe distances from the main parts of welding machines, and also conditions and instructions for arc welding by patients with pacemakers. To ensure patient safety, patients should maintain suggested safe distances, use direct current with minimal possible amplitude, and weld in short intervals. Additionally, their pacemakers should be set to bipolar configuration.

Electromagnetic danger of electric and hybrid vehicles

Problem statement. In electric and hybrid transport, passengers sit very close to the electrical system of considerable power, usually for a considerable time. People are concerned about the level of frequency, intensity of electromagnetic radiation, and the time spent in transport. The relatively high currents achieved in these systems and the short distances between power devices and passengers mean that the latter can be exposed to the corresponding magnetic fields. This means that there is a need to assess the electromagnetic environment inside these vehicles before they are put on the market. When designing electric and hybrid vehicles and their components, it is necessary to take into account the hazards of magnetic field exposure to drivers, passengers and the environment. The aim is to study the effect of electromagnetic radiation on people and improve the efficiency of vehicle operation by assessing the electromagnetic safety of electric and hybrid vehicles at the stage of their operation, as well as to improve methods for assessing electromagnetic radiation depending on operating conditions. Methodology. Methods are a systematic approach to research, protection against electromagnetic radiation in transport, conducting measurements of electromagnetic radiation in electric and hybrid transport, finding out the spatially strong inhomogeneity of the magnetic field and building 3D topology using numerous uniformly distributed magnetic field sensors in the vehicle interior, i.e. by a differential phase-gradient method for the study of ultra-low frequency amplifiers from 0.001 - 100 Hz of geomagnetic variations, a method of testing magnetic fields. This method allows using three three-component magnetic sensors arranged in a triangle at a short distance from each other (magnetic gradiometer) to construct a vector of gradients and phase velocities of magnetic variations for any of the three components of magnetic fields. As a result, the phase-gradient method has found its application for measuring magnetic fields in electric and hybrid vehicles, as well as for detecting the topology of magnetic fields, taking into account their extreme spatial heterogeneity, the sensors in the cabin should be located quite densely, i.e., the number of sensors should be at least 10-20 (evenly at a distance of ten centimeters at floor level, at head level of drivers and passengers, etc.). Scientific novelty: the study of electrical equipment in electric and hybrid transport has shown that the source of electromagnetic fields, which have a strong temporal and spatial heterogeneity in the frequency range from 0 to hundreds of megahertz, that they are a superposition of fields from many sources (from electric motors, traction batteries, live elements, various electrical equipment (starting and braking resistance, group switches, rheostat units, electrical circuits for ventilation, lighting, heating, etc.). Practical relevance. The problems of determining the moment of occurrence of electromagnetic hazards in electric and hybrid vehicles are considered. It is established that electronic devices on board are usually higher in frequency than magnetic fields, which is associated with changes in traffic modes. Safety measures against electromagnetic radiation in electric and hybrid modes of transport are presented.

Grain Seed Treatment by a Low-Frequency Electromagnetic Field

The paper notes the potential for enhancing seed productivity through exposure to an electromagnetic field. It touches upon both theoretical and practical considerations for developing an experimental laboratory plant for pre-sowing seed treatment using a low-frequency electromagnetic field and aiming to achieve a magnetobiological effect. (Research purpose) The study aims to investigate the influence of low-frequency electromagnetic field on the composition and properties of grain seeds. (Materials and methods) Standard emitters, characterized by a magnetic induction variability of 3-75 millitesla and a radiation frequency of 1-100 Hertz, were employed to ensure the necessary treatment parameters for a batch of seeds. (Results and discussion) The study investigates the impact of magnetization on the germination process, germination energy, and the physical and chemical properties of seeds subjected to different parameters of a low-frequency electromagnetic field (ranging from 3 to 75 millitesla in magnetic induction and a radiation frequency of 10-16 Hertz).The quality of the effect was analyzed with respect to the installation parameters and seed mass, ranging from 10 to 500 grams, across various cereal crops. Subsequently, specific modes were identified, and a functional irradiation program was devised to ensure a highly effective impact on seeds, optimizing their germination, sprouting and development. (Conclusions) The impact of a low-frequency electromagnetic field on the composition and properties of grain has been studied. An experimental laboratory plant with sources of a low-frequency electromagnetic field has been developed and irradiation modes have been justified. The pre-sowing treatment of an industrial batch, the magnetobiological effect is contingent upon several factors, including the crop type and variety, activation of a biological complex in a cell that initiates the development of a seedling, seed quality and moisture content, the presence of microorganisms on the surface, pathogenic ones included, and the characteristics of irradiation sources and energy parameters. The parameters of the low-frequency electromagnetic field were determined as follows: magnetic induction ranging from 3 to 75 millitesla, a frequency 10-16 Hertz, and seed weight varying from 10 to 500 grams. These identified parameters will be applied in the development of an industrial unit designed for the preparation of seed material and enhancement of its sowing properties.

Occupational exposure to electromagnetic fields from dental devices: A descriptive study

Abstract&#x0D; &#x0D; Objective: Electromagnetic Field sources which are widely used as part of the operating mechanism occupational exposure occurs with the electricity is generated, distributed or usage in the everyday environment. We aimed to obtain the Extremely Low Frequency-Magnetic Field exposure profile for dental health workers from electrical devices used in dentistry. &#x0D; Methods: Measurements were performed while appliances under working conditions, 10 cm distance with the device for 6 minutes and for 7 days. The highest measured value in every 10 second was recorded. The mean ± SD of minimum and maximum Extremely Low Frequency-Magnetic Field for high-speed dental handpiece with LED, low-speed dental handpiece, model-trimming machine, automatic boil-out unit, steam machine, vacuum device, and polishing machine were recorded in milliGauss. &#x0D; Results: The values which obtains from model-trimming machine and polishing machine were remarkable (809.17 ± 37.70 / 975.00 ± 10.27, 649.33 ± 201.37 / 1367.00 ± 32.17, respectively). Conclusion: The results show that periodic Electromagnetic Field exposure measurements should be conducted to obtain more detailed information about workplace exposures and sources.&#x0D; &#x0D; Keywords: Health, electromagnetic field, extremely low-frequency field, exposure, occupational

Electromagnetic Fields: Insight into Sources, and Their Effects on Vital Organs and the Risk of Cancer

Background: Electromagnetic radiation has become an extensive new pollution source in modern civilization. Therefore, the biological effects of electromagnetic radiation have attracted considerable attention worldwide. Objectives: The current review was aimed to highlight on sources of electromagnetic fields and their effects on vital organs and the risk of cancer. Electromagnetic sources can be classified into natural electromagnetic sources (sun, some distant stars, atmospheric discharges like thunder, or human body) and unnatural or human made sources (printers, vacuum cleaners, cellular phones, hair dryers, refrigerators, washing machines, kettles microwaves, cables that carry electrical currents, television and computers, electrical home gadgets, radio and television base stations, mobile phone base stations and phone equipment), home wiring airport, and transformers. Electromagnetic fields (EMFs) are electromagnetic waves less than 300 GHz, that are divided into extremely low frequencies (ELFs; 3–3,000 Hz), involving high-voltage transmission lines and in-house wiring; and radiofrequencies (RFs; 30 kHz to 300 GHz), involving mobile phones, smart devices, base stations, WiFi, and 5G technologies. Cell phone technology is an integral part of everyday life and its use is not only restricted to voice conversations but also conveying news, high-resolution pictures, and the internet. Exposure to electromagnetic fields might produce oxidative stress, sperm damage, DNA damage, changes in the chromatin conformation, formation of micronucleus in different cell types, gene expression, enzyme activity, and changes in the structure and function of cell membrane, stimulated an increase in apoptosis and biosynthesis of plasma metallothionein and corticosterone. It causes headaches, chronic fatigue, heart problems, stress, nausea, chest pain, gastrointestinal issues, pain in the muscles and joints, sweating, neurocognitive disturbances, eye burning, nose, ear, and throat issues, bad effects on reproductive, central nervous, endocrine, cardiovascular, and immune systems. Also, it increases anxiety-related behavior; spatial memory, and learning deficits in male mice offspring, decreased thermal pain perception, induced a sleep disturbance, latency, and day dysfunction especially in females, a change in memory performance, damage to the lens epithelial cells of rabbits after 8 hours of exposure to microwave radiation, produced lens opacity in rats, which is linked to the production of cataracts, and derangement of chicken embryo retinal differentiation. There are a relationship between exposure to electromagnetic fields and the increased incidence of the occurrence of some tumors types, particularly brain cancer and leukemia. EMFs induce damage of tissues by increasing free radicals and changing the antioxidant defense systems of tissues, eventually leading to oxidative stress which leads to behavioral, histopathological and biochemical alterations. Exposure to radar, which uses RF fields above 6 GHz similar to 5 G causes effects on production of cancer at different sites, and other diseases. The possible mechanism proposed of how EMFs lead to cancer is the impact of EMFs on free radical combination rates in certain enzymes, such as coenzyme B12-dependent ethanolamine ammonia lyase. The enzyme reaction rate may be amplified by a factor of up to 100. A case-control studies found an increased risk of gliomas, acoustic neuromas, and temporal lobe tumours in users with highest self-reported cell phone use. Exposure of experimental animals to microwave radiation caused a decrease in learning and memory ability, abnormal hippocampal morphology and abnormal Electroencephalogram. Also, it could lead to a decrease in norepinephrine and epinephrine contents in the brain, leading to neurotransmitter production disorders. Conclusion: It can be concluded that electromagnetic sources classified into natural electromagnetic and human made sources. EMFs) are electromagnetic waves less than 300 GHz are divided into extremely low frequencies and radiofrequencies. Exposure to electromagnetic fields might produce oxidative stress, which leads to histopathological and biochemical alterations in different body organs and increased risk of gliomas, acoustic neuromas, and temporal lobe tumours in users with highest self-reported cell phone use. Further studies are needed to confirm these effects in human and experimental animals.

A study of the long term changes in the electromagnetic environment using data from continuous monitoring sensors in Greece

Owing to the advancement of wireless technologies, there is a strong public perception of increasing exposure to Radiofrequency (RF) electromagnetic fields (EMF). The aim of this study is to determine the evolution of EMF in the environment, and consequently, human exposure to them, over a period of about two decades, spanning from the end of 2003 until February 2022. The study is based on data collected by two non-ionizing radiation monitoring networks in Greece. The networks consist of fixed EMF sensors that register the RMS electric field value every 6 min, on a 24 h basis. We used the Seasonal–Trend decomposition method using (LOESS), known as the STL method to decompose the time series into trend, seasonal, and noise components. Additionally, since the sensors include frequency filters for separating the cellular frequencies, the recorded data were used to identify the exposure contribution by cellular networks in comparison to other EMF sources. The study indicates that RF-EMF do not explicitly decrease or increase but rather fluctuate over time. Similarly, the contribution of mobile cellular networks to the total field change over time.

Electron–positron plasma in BBN: Damped-dynamic screening

We characterize in detail the dense e−e+γ plasma present during the Big-Bang Nucleosynthesis (BBN) and explore how it is perturbed electromagnetically by “impurities, i.e., spatially dispersed protons and light nuclei undergoing thermal motion. The internuclear electromagnetic screened potential is obtained (analytically) using the linear response approach, allowing for the dynamic motion of the electromagnetic field sources and the damping effects due to plasma component scattering. We discuss the limits of the linear response method and suggest additional work needed to improve BBN reaction rates in the primordial Universe. Our theoretical methods describing the potential between charged dust particles align with previous studies on planetary and space dusty plasma and could have a significant impact on the interpretation of standard cosmological model results.

Dosimetric assessment in the brain for downlink EMF exposure in Korean mobile communication networks

Because the position and direction of the human body is not fixed in an actual environment, the incidence direction of the electromagnetic field (EMF) from mobile communication base stations, WiFi access points, broadcasting towers, and other far-field sources is arbitrary. To analyze the overall health effects of radio frequency EMF exposure, the dosimetric assessment for such environmental exposures created from an unspecified number of sources in daily life, along with exposures from specific EMF sources, must be quantified. This study is aimed at numerically evaluating the time-averaged specific absorption rate (SAR) of the human brain for environmental EMF exposure in the frequency range of 50–5800 MHz. Whole-body exposure to EMFs that are evenly incident spatially is considered. By comparing the results of several incidence directions and the number of polarizations, an optimal calculation condition has been derived. Finally, based on the results measured in Seoul at the end of 2021, the SAR and daily specific energy absorption (SA) in the brains of both a child and an adult for downlink exposures from 3G to 5G base stations are reported. Comparison results of the daily brain SA for exposure to DL EMF in all 3G to 5G mobile networks and exposure to a 10-min voice call (uplink EMF) using a mobile phone connected to a 4G network show that the SA from the downlinks is much higher than that from the uplinks.

Analyzing the SAR in Human Head Tissues under Different Exposure Scenarios

This paper deals with the assessment of induced specific absorption rate (SAR) in various human models under different exposure scenarios, including both laboratory measurements and simulations. Firstly, SAR values were measured in a standardized SAR laboratory using a phantom for two radiofrequency electromagnetic field (RF-EMF) sources at 900 MHz and 1800 MHz. These laboratory measurements served as a reference for SAR calculations conducted on a specific anthropomorphic mannequin (SAM) using a computer simulation technology (CST) program, thus enabling the determination of antenna location and excitation signal levels for further evaluation. Subsequently, simulations were carried out with CST to evaluate average SAR for the head and for specific head tissues such as the brain, muscles, and fat. Realistic computational human models were also used alongside SAM in CST to explore the influence of gender, age, and tissue type on SAR. Various power levels representing low, moderate, and high RF-EMF exposure were applied to the human models to compare against basic restrictions and reference levels. The simulation results indicate significantly higher SAR values calculated for 1800 MHz compared with 900 MHz. The ratio of the highest SAR values at 1800 MHz to 900 MHz is approximately 1.70 for a baby, 2.59 for a child, and 2.84 for both adult female and adult male. While the SAR values for the brain, fat, muscle, and head are comparable at 900 MHz for the baby, the brain’s SAR value at 1800 MHz stands out significantly from the other tissues. In contrast with the baby, the difference in SAR values between 900 MHz and 1800 MHz is more pronounced for the child, adult female and adult male. The lowest SAR values at 900 MHz and 1800 MHz were obtained for brain tissue in all human models, while the head has the highest SAR value. The maximum SAR change ratio between the brain and the head is calculated to be 4.44 for the male at 1800 MHz. The results reveal that, although the applied electromagnetic field levels were below reference levels for general public local exposure, some local SAR values exceeded the International Commission of Non-Ionizing Radiation Protection’s basic restriction for the general public at certain power levels, particularly at 1800 MHz. The SAR analysis derived from this study is significant in understanding the impact of wireless technologies on health, establishing safety standards, guiding technology advancement, conducting risk assessments, and increasing public awareness.