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Flexible paper-based materials play a crucial role in the field of flexible electromagnetic shielding due to their thinness and controllable shape. In this study, we employed the wet paper forming technique to prepare carbon fiber paper with a thickness gradient. The electromagnetic shielding performance of the carbon fiber paper varies with the ladder-like thickness distribution. Specifically, an increase in thickness gradient leads to higher reflectance of the carbon fiber paper. Within the X-band frequency range (8.2–12.4 GHz), reflectivity decreases as electromagnetic wave frequency increases, indicating enhanced penetration of electromagnetic waves into the interior of the carbon fiber paper. This enhancement is attributed to an increased fiber content per unit area resulting from a greater thickness gradient, which further enhances reflection loss and promotes internal multiple reflections and scattering effects, leading to increased absorption loss. Notably, at a 5 mm thickness, our carbon fiber paper exhibits an impressive average overall shielding performance, reaching 63.46 dB. Moreover, it exhibits notable air permeability and mechanical properties, thereby assuming a pivotal role in the realm of flexible wearable devices in the foreseeable future. [ABSTRACT FROM AUTHOR]

An ideal surface-enhanced Raman scattering (SERS) substrate should exhibit a high electromagnetic field enhancement factor, simple preparation repeatability low cost. Here, we prepared a reproducible nanoplasmonic paper SERS substrate via a silver mirror reaction (SMR) and AgNO3-ascorbic acid (AgNO3-ASC) solution treatment method to reduce Ag nanoparticles (Ag NPs) on the surface of the flexible glass fiber filter paper (GFP). GFP with Ag NPs (AgNPs@GFP) was used for SERS to detect melamine molecules (MMs). The results showed that melamine molecules' detection limit was up to 1 ng/mL. The maximum enhancement factor of the SERS signal reached 838, and the sensitivity was 150. This strategy of fabricating SERS substrates based on GFP can provide a new way to prepare a low-cost flexible SERS substrate and increase the sensitivity of biomolecules. [ABSTRACT FROM AUTHOR]

Extremely low frequency (60 Hz) electric and magnetic field levels were measured at three Canadian pulp and paper mills, using area point-in-time measurements. Most electric field levels were below the limit of detection of 1 V/m (92 of 132 measurements); the highest measured field was 47 V/m. Measured magnetic field strengths ranged from less than the limit of detection (0.125 mG, 2 of 132 measurements) to 706 mG, with a median of 1.6 mG. Magnetic field levels were higher in mills that consume more electric power, but worker exposures could not be predicted according to plant power consumption. Overall, electric and magnetic field levels in the three pulp and paper mills were similar to those experienced by the general population. However, maximum magnetic field intensities in some areas were as high as those experienced by electrical workers.

The unprecedented exposure of radiofrequency electromagnetic field (RF-EMF) to humans from mobile communications raises serious public concern about the possibility of unexpected adverse health effects and has stimulated authorities to adopt precautionary exposure limits. These limits are distinctly different across countries, and the causes of these differences are unclear from the literature. This article is the first empirical analysis on the determinants of RF-EMF exposure legislation, using a novel cross-sectional database of 164 countries worldwide. The analysis shows that decentralization and mobile competition in countries with low mobile network deployment tend to promote more stringent RF-EMF exposure limits across the dataset with 164 countries. In more decentralized countries, the regions had a greater influence on national legislation and could accommodate local demands with the advent of mobile technology in the 2000s. In contrast, decentralization and mobile competition in countries with high levels of mobile network deployment tend to relax RF-EMF exposure limits in the sample of 61 countries with fifth-generation (5G) technology. Indeed, restrictive RF-EMF exposure limits are constraining 5G deployment in a context of the widespread adoption of mobile-broadband technologies. These results should be useful for policymakers and mobile operators alike to anticipate the outcome of legislation in countries that have yet to introduce 5G technology. The results should also be useful when reviewing policies and strategies for the implementation of the upcoming 6G technology in frequency bands that will be increasingly higher (above 6 GHz up to THz for very local usage), and hence where the health effects on humans are less well studied., (© 2024 Society for Risk Analysis.)

Purpose: To introduce a method for the estimation of the ideal current patterns (ICP) that yield optimal signal-to-noise ratio (SNR) for realistic heterogeneous tissue models in MRI., Theory and Methods: The ICP were calculated for different surfaces that resembled typical radiofrequency (RF) coil formers. We constructed numerical electromagnetic (EM) bases to accurately represent EM fields generated by RF current sources located on the current-bearing surfaces. Using these fields as excitations, we solved the volume integral equation and computed the EM fields in the sample. The fields were appropriately weighted to calculate the optimal SNR and the corresponding ICP. We demonstrated how to qualitatively use ICP to guide the design of a coil array to maximize SNR inside a head model., Results: In agreement with previous analytic work, ICP formed large distributed loops for voxels in the middle of the sample and alternated between a single loop and a figure-eight shape for a voxel 3-cm deep in the sample's cortex. For the latter voxel, a surface quadrature loop array inspired by the shape of the ICP reached 87 . 5 % $$ 87.5\% $$ of the optimal SNR at 3T, whereas a single loop placed above the voxel reached only 55 . 7 % $$ 55.7\% $$ of the optimal SNR. At 7T, the performance of the two designs decreased to 79 . 7 % $$ 79.7\% $$ and 49 . 8 % $$ 49.8\% $$ , respectively, suggesting that loops could be suboptimal at ultra-high field MRI., Conclusion: ICP can be calculated for human tissue models, potentially guiding the design of application-specific RF coil arrays., (© 2023 International Society for Magnetic Resonance in Medicine.)

This study compares the performance of graph convolutional neural network (GCN) models with conventional natural language processing (NLP) models for classifying scientific literature related to radio frequency electromagnetic field (RF-EMF). Specifically, the study examines two GCN models: BertGCN and the citation-based GCN. The study concludes that the model achieves consistently good performance when the input text is long enough, based on the attention mechanism of BERT. When the input sequence is short, the composition parameter λ, which combines output values of the two subnetworks of BertGCN, plays a crucial role in achieving high classification accuracy. As the value of λ increases, the classification accuracy also increases. The study also proposes and tests a simplified variant of BertGCN, revealing performance differences among the models under two different data conditions by the existence of keywords. This study has two main contributions: (1) the implementation and testing of a variant of BertGCN and citation-based GCN for document classification tasks related to radio frequency electromagnetic fields publications, and (2) the confirmation of the impact of model conditions, such as the existence of keywords and input sequence length, in the original BertGCN. Although this study focused on a specific domain, our approaches have broader implications that extend beyond scientific publications to general text classification.

Abstract: The exponential diffusion of wearable medical devices (WMD) in recent years has involved people of all ages, including workers. Workers who use WMDs should be considered at a particular risk from electromagnetic fields, and in accordance with EU Directive 2013/35/EU, they require an individual risk assessment. Currently, there is no international standard that provides specific guidance on how to perform such a risk assessment. This paper focuses on the effects of electromagnetic fields on WMDs and does not consider the direct effects on human body tissues. It aims to offer practical recommendations to employers and/or health physicists for the risk assessment of workers with WMDs. Focusing on EU countries, we first describe the requirements outlined by the technical standard for the electromagnetic compatibility (EMC) of medical electrical equipment EN 60601-1-2. Then, some general guidelines on how to perform the risk assessment are provided. The assessment can be conducted by comparing the field values measured in the workplace with the immunity test levels specified in the technical standards of medical electrical equipment. If the measured values are lower than the immunity test levels indicated in the standard and the distance from the electromagnetic source is greater than the distance used by the manufacturer during the EMC (electromagnetic compatibility) tests (typically 30 cm), the risk for the worker may be considered acceptable. However, if the measured values exceed the immunity test levels or the distance criteria, a specific evaluation based on a case-by-case analysis is required., (Copyright © 2024 Health Physics Society.)

The paper published by Nath et al. (Urban Ecosystems 25:1279–1295, 2022) analyzes the influence of different ecological factors and covariates on House Sparrow (Passer domesticus) abundance but criticizes previous research without explaining in depth the scientific reasons for it and reaches conclusions not supported by the authors' own data nor by existing knowledge and scientific evidence. They state that studies on the impacts of electromagnetic radiation (EMR) on birds outside laboratory conditions carried out in the past did not consider other ecological factors that could also influence the life history needs of the species. However, precisely the opposite is true; the studies carried out so far, taking into account most of the possible factors to consider, including urbanization, have not been able to solve the enigma of the House Sparrow decline in many of the world's cities. Thus, it is necessary to propose new possible causes not considered so far. Among the few that remain to be tested is the electromagnetic radiation hypothesis, which was proposed by two independent research teams in two different countries. This paper is a reply of the work developed by Nath et al. (Urban Ecosystems 25:1279–1295, 2022) that highlight their inconclusive results and methodological flaws due to the correlation observed between radiofrequency electromagnetic fields (RF-EMF) and urbanization, complement their results showing negative correlations when testing House Sparrow abundance with electromagnetic radiation levels correcting for the percentage of builtup, and clarify some statements and misconceptions (importance of non-thermal effects). [ABSTRACT FROM AUTHOR]

The insulation status of oil-impregnated paper (OIP) bushings directly indicates their operational condition. Damp defects constitute the primary factor contributing to the deterioration of oil-paper insulation. In this paper, the overall moisture distribution of capacitor cores with three damp defects (steady-state, transient, anzd tail moisture damp defect) and its effect on the electric field were studied. A moisture diffusion model for OIP bushing was established based on Finite Element Method (FEM) software, and it was also verified by moisture diffusion experiments. Then, the overall moisture distribution of the capacitor core under three damp defects was investigated. The findings indicate significant variation in the overall moisture distribution of the capacitor core influenced by factors such as aluminum foil and temperature. Furthermore, the relative permittivity of the oilimpregnated paper was computed. Subsequently, the impact of various moisture-induced defects on the electric field was determined. Simulation results unveiled distortion in the electric field of each electrode within the capacitor core. Specifically, the electric field of the zero electrode increased, while that of the outermost electrode decreased in all three damp defect scenarios. The conclusions drawn can thus be used for intelligent operation and condition assessment of OIP bushings. [ABSTRACT FROM AUTHOR]

In order to cope with the current engineering demand for increasing the current‐carrying capacity of resin impregnated paper (RIP) bushing, an optimization scheme of RIP bushing was proposed in this paper. Simulation and experimental studies were carried out to verify the rationality of the scheme. An improved simulation method was proposed. To ensure as much accuracy as possible, the physical model of simulation considers the influence of heat conduction, thermal convection and thermal radiation process according to the actual operation environment. To boost the computational efficiency, the improved method simplified the relationship between temperature and heating power of the current‐carrying conductor as a fitting formula to avoid the iterative calculation between electromagnetic field simulation and temperature field simulation. The temperature rise test was carried out according to the engineering requirement and the standard international electro technical commission (IEC) 60137:2008. The simulation and experimental results show that the RIP bushing can carry a current with the heating power of its conductor equivalent to that generated by a 50‐Hz current of 6736 A while running in a converter station. It is a breakthrough of the current‐carrying capacity of high voltage bushing. Meanwhile, the regularity of temperature distribution of the RIP bushing was discussed. [ABSTRACT FROM AUTHOR]

This document is an editorial that discusses the concept of electromagnetic (EM) field theories of consciousness. It highlights the growing interest in this type of solution for understanding consciousness and its philosophical and physical aspects. The document also includes summaries of various research papers on EM field theories of consciousness, which explore the role of EM fields in understanding consciousness and propose different frameworks and theories to explain its mechanisms. The papers discuss topics such as brain activity, EM field oscillations, qualia, and the boundary problem in consciousness studies. Overall, these papers contribute to the ongoing exploration of EM field theories of consciousness and offer potential avenues for further research. [Extracted from the article]

Hypoxia in surface waters driven by warming climate and other anthropogenic stressors is a major conservation concern, and technological solutions for water quality remediation are sorely needed. One potential solution involves the use of low-intensity electromagnetic fields (EMFs) to increase dissolved oxygen levels, but potential collateral effects of the EMFs on aquatic animals have not been formally evaluated. We examined the effects of EMF exposure on wild-caught, captive sunfish (Lepomis spp.) over 8-day and 3-day exposures, with and without aeration in mesocosms and stock tanks (respectively). We also quantified ambient fish abundance in close proximity to EMF devices deployed in Opinicon Lake (ON). We found no significant differences in a suite of blood-based stress physiology biomarkers, behaviors, and putative aerobic capacities between EMF and control conditions over 8 days. Aerated mesocosms equipped with activated EMFs consistently had higher oxygen levels in the water than aerated controls. There were no differences in mortality during 3-day oxygen depletion trials under EMF or control conditions, and we detected no differences in fish abundance when the devices were activated in the lake. Our findings suggest that deploying EMF devices in field settings is not likely to exert negative effects on exposed fish populations. PRACTITIONER POINTS: Low-cost, low-energy technological solutions to remediate aquatic hypoxia are sorely needed Electromagnetic fields (EMFs) can increase oxygen flux across air/water interfaces and increase dissolved oxygen levels We found no evidence of negative effects of EMFs on fish physiology or behavior and our results support their use in alleviating hypoxic conditions., (© 2022 Water Environment Federation.)

An assembly of resistive paper and liquid crystal sheet, conveniently and cheaply constructed for visual detection of the electric fields associated with an rf probe, is presented. Electrical asymmetries, and "hot-spots" usually associated with conservative electric fields, are easily visualized by the color patterns displayed. The device is of considerable assistance in probe design and the minimization of dielectric loss.

We have used laser Stokes polarimetry to study changes in the structure of paper for offset printing when exposed to a high-frequency electromagnetic field. We have shown that the effect of a high-frequency electromagnetic field on paper appears as a decrease in the structural ordering of the material and a change in the shape of the indicatrix of the reflected radiation power from an He-Ne laser at the wavelength 632.8 nm, a decrease in the bidirectional reflection and transmission coefficients of the paper. We have established that when the force lines of the magnetic component of the high-frequency electromagnetic field are oriented perpendicular to the plane of the sheet of paper, we observe a more substantial decrease in the anisotropy in the surface layer and within the interior (the volume) of the paper than when the lines of force are oriented parallel to the plane of the paper. [ABSTRACT FROM AUTHOR]

At the end of the paper production process, reducing its moisture content is achieved by passing the finished product in continuous flow through an electric oven. This paper assumes humidity control, which in turn determine the electrical conductivity of the paper. The operating principle of non-contact method is: a transmitting coil Tx supplied with alternating current at an audio frequency is placed on the paper comes out of the oven. A reception coil Rx is located at a short distance, s, away from the Tx coil. The magnetic field varies in time and emission Tx coil induces circular currents of very low intensity in wet paper. These currents generate a secondary magnetic field Hs , which is detected by the receiver Rx coil together with the magnetic field Hp. The ratio of the secondary magnetic field Hs and Hp primary magnetic field (Hs \ Hp) is directly proportional to the conductivity of the paper. Thus it is possible to build a device to measure the conductivity of paper contactless electromagnetic technique. [ABSTRACT FROM AUTHOR]

The materials used in electrical and electronic applications have great importance and broader applications, but they have severe electromagnetic interference (EMI). These materials have extensive applications in broadcasting, medical industries, research, defence sectors, communication and similar fields. The EMI can be addressed by using effective EMI shielding materials. This review presents a detailed, comprehensive description for making electromagnetic interference shielding material by recycling various wastes. It starts with highlighting the overview of electromagnetic interference shielding (EMI) and its theoretical aspects. It provides a comprehensive and detailed understanding of recent trends in the novel approaches towards fabricating EMI shielding from industrial waste, agricultural waste and other miscellaneous wastes. This paper critically reviews the works related to the recycling of wastes like red mud (waste from the aluminium refining industry), ground tyre rubber, tea waste (biowaste) from tea industries, bagasse (waste from sugar cane industry), peanut and hazelnut shells (agricultural waste), waste tissue paper and polyethylene and other miscellaneous wastes like hydrocarbon carbon black and ash for the fabrication of highly effective electromagnetic (EM) interference shielding materials. Highly effective results have been reported using red mud showing maximum efficiency of 51.4 dB in X-band range, various agricultural waste displaying reflection loss of up to - 87.117 dB (in the range 0.01 to 20 GHz) and miscellaneous waste giving EMI SE of 80 dB in X-band frequency. A separate section is dedicated to emphasizing future work and recommendations., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This study compares the performance of graph convolutional neural network (GCN) models with conventional natural language processing (NLP) models for classifying scientific literature related to radio frequency electromagnetic field (RF-EMF). Specifically, the study examines two GCN models: BertGCN and the citation-based GCN. The study concludes that the model achieves consistently good performance when the input text is long enough, based on the attention mechanism of BERT. When the input sequence is short, the composition parameter  λ , which combines output values of the two subnetworks of BertGCN, plays a crucial role in achieving high classification accuracy. As the value of  λ  increases, the classification accuracy also increases. The study also proposes and tests a simplified variant of BertGCN, revealing performance differences among the models under two different data conditions by the existence of keywords. This study has two main contributions: (1) the implementation and testing of a variant of BertGCN and citation-based GCN for document classification tasks related to radio frequency electromagnetic fields publications, and (2) the confirmation of the impact of model conditions, such as the existence of keywords and input sequence length, in the original BertGCN. Although this study focused on a specific domain, our approaches have broader implications that extend beyond scientific publications to general text classification. [ABSTRACT FROM AUTHOR]

Due to the continuous rising ambient levels of nonionizing electromagnetic fields (EMFs) used in modern societies-primarily from wireless technologies-that have now become a ubiquitous biologically active environmental pollutant, a new vision on how to regulate such exposures for non-human species at the ecosystem level is needed. Government standards adopted for human exposures are examined for applicability to wildlife. Existing environmental laws, such as the National Environmental Policy Act and the Migratory Bird Treaty Act in the U.S. and others used in Canada and throughout Europe, should be strengthened and enforced. New laws should be written to accommodate the ever-increasing EMF exposures. Radiofrequency radiation exposure standards that have been adopted by worldwide agencies and governments warrant more stringent controls given the new and unusual signaling characteristics used in 5G technology. No such standards take wildlife into consideration. Many species of flora and fauna, because of distinctive physiologies, have been found sensitive to exogenous EMF in ways that surpass human reactivity. Such exposures may now be capable of affecting endogenous bioelectric states in some species. Numerous studies across all frequencies and taxa indicate that low-level EMF exposures have numerous adverse effects, including on orientation, migration, food finding, reproduction, mating, nest and den building, territorial maintenance, defense, vitality, longevity, and survivorship. Cyto- and geno-toxic effects have long been observed. It is time to recognize ambient EMF as a novel form of pollution and develop rules at regulatory agencies that designate air as 'habitat' so EMF can be regulated like other pollutants. Wildlife loss is often unseen and undocumented until tipping points are reached. A robust dialog regarding technology's high-impact role in the nascent field of electroecology needs to commence. Long-term chronic low-level EMF exposure standards should be set accordingly for wildlife, including, but not limited to, the redesign of wireless devices, as well as infrastructure, in order to reduce the rising ambient levels (explored in Part 1). Possible environmental approaches are discussed. This is Part 3 of a three-part series., (© 2021 Walter de Gruyter GmbH, Berlin/Boston.)

Ambient levels of nonionizing electromagnetic fields (EMF) have risen sharply in the last five decades to become a ubiquitous, continuous, biologically active environmental pollutant, even in rural and remote areas. Many species of flora and fauna, because of unique physiologies and habitats, are sensitive to exogenous EMF in ways that surpass human reactivity. This can lead to complex endogenous reactions that are highly variable, largely unseen, and a possible contributing factor in species extinctions, sometimes localized. Non-human magnetoreception mechanisms are explored. Numerous studies across all frequencies and taxa indicate that current low-level anthropogenic EMF can have myriad adverse and synergistic effects, including on orientation and migration, food finding, reproduction, mating, nest and den building, territorial maintenance and defense, and on vitality, longevity and survivorship itself. Effects have been observed in mammals such as bats, cervids, cetaceans, and pinnipeds among others, and on birds, insects, amphibians, reptiles, microbes and many species of flora. Cyto- and geno-toxic effects have long been observed in laboratory research on animal models that can be extrapolated to wildlife. Unusual multi-system mechanisms can come into play with non-human species - including in aquatic environments - that rely on the Earth's natural geomagnetic fields for critical life-sustaining information. Part 2 of this 3-part series includes four online supplement tables of effects seen in animals from both ELF and RFR at vanishingly low intensities. Taken as a whole, this indicates enough information to raise concerns about ambient exposures to nonionizing radiation at ecosystem levels. Wildlife loss is often unseen and undocumented until tipping points are reached. It is time to recognize ambient EMF as a novel form of pollution and develop rules at regulatory agencies that designate air as 'habitat' so EMF can be regulated like other pollutants. Long-term chronic low-level EMF exposure standards, which do not now exist, should be set accordingly for wildlife, and environmental laws should be strictly enforced - a subject explored in Part 3., (© 2021 Walter de Gruyter GmbH, Berlin/Boston.)

Ambient levels of electromagnetic fields (EMF) have risen sharply in the last 80 years, creating a novel energetic exposure that previously did not exist. Most recent decades have seen exponential increases in nearly all environments, including rural/remote areas and lower atmospheric regions. Because of unique physiologies, some species of flora and fauna are sensitive to exogenous EMF in ways that may surpass human reactivity. There is limited, but comprehensive, baseline data in the U.S. from the 1980s against which to compare significant new surveys from different countries. This now provides broader and more precise data on potential transient and chronic exposures to wildlife and habitats. Biological effects have been seen broadly across all taxa and frequencies at vanishingly low intensities comparable to today's ambient exposures. Broad wildlife effects have been seen on orientation and migration, food finding, reproduction, mating, nest and den building, territorial maintenance and defense, and longevity and survivorship. Cyto- and geno-toxic effects have been observed. The above issues are explored in three consecutive parts: Part 1 questions today's ambient EMF capabilities to adversely affect wildlife, with more urgency regarding 5G technologies. Part 2 explores natural and man-made fields, animal magnetoreception mechanisms, and pertinent studies to all wildlife kingdoms. Part 3 examines current exposure standards, applicable laws, and future directions. It is time to recognize ambient EMF as a novel form of pollution and develop rules at regulatory agencies that designate air as 'habitat' so EMF can be regulated like other pollutants. Wildlife loss is often unseen and undocumented until tipping points are reached. Long-term chronic low-level EMF exposure standards, which do not now exist, should be set accordingly for wildlife, and environmental laws should be strictly enforced., (© 2021 Walter de Gruyter GmbH, Berlin/Boston.)

The relation between ageing and space charge is a hot area, but there is little direct evidence. In this paper, oil-paper samples were exposed to 20-kV/mm DC electrical field, 130°C temperature or both 20-kV/mm DC electrical field and 130°C temperature separately. Charge transport through them was analyzed at intervals by the pulsed electroacoustic (PEA) method. We find that the quantity of trapped charge increases with stressing durations, no matter what kind of stress oil-paper is exposed to. That indicates that energy release through space charge movement, such as charge trapping/detrapping and recombination, is another reason for traps generation besides deterioration caused by thermal ageing. However, because the difference in cellulose degradation mechanism among them, charge transport dynamics are thereby different under different stressing conditions. Space charge accumulates faster inner electrothermally stressed oil-paper than that inner another two kinds of oil-paper, and the sign of trapped charge is positive if oil-paper is electrically or electro-thermally stressed. The latter behavior is discussed in terms of electromagnetic dynamics due to cavity within oil-paper once there is external electric field. [ABSTRACT FROM PUBLISHER]