Application Of Electromagnetic Fields Research Articles

Graphene‐Integrated Reconfigurable Metasurface for Independent Manipulation of Reflection Magnitude and Phase

AbstractReconfigurable metasurfaces are highly desirable for applications including dynamical camouflaging, intelligent electromagnetic (EM) skin and systems due to their tunable EM features or functions. So far most of the existing reconfigurable metasurfaces are developed by modulating their amplitude or phase. It is still very challenging to simultaneously achieve dynamical control of amplitude and phase in one design. This study reports a reconfigurable metasurface that can realize independent control of reflection magnitude and phase with the external bias voltages. In this metasurface, the graphene capacitor structure is used as an amplitude‐tuning layer for controlling the reflection magnitude by changing the effective sheet resistance of graphene, while the reflection phase is tuned by switching PIN diodes loaded in a periodic metallic structure. Such metasurface can control the scattering wave directions through phase coding, and the variation of graphene resistance can further modulate the intensity of the scattering beams. In addition, the metasurface can also function as a radar absorber where the absorbing magnitude and frequency can be dynamically tuned. Good agreements between simulations and experiments demonstrate its powerful ability to manipulate the EM waves by simultaneously tuning the reflection magnitude and phase, indicating a wide range of potential applications in EM fields.

Pathophysiological mechanisms of the therapeutic action of alternating electromagnetic fields in the treatment of osteoarticular pathology

Treatment of osteoarticular pathology with an alternating electromagnetic field (AEMF) is used today as a promising, non-invasive and safe strategy of physiotherapy. It has been shown that the action of alternating electromagnetic fields on the musculoskeletal system triggers signaling cascades that effectively contribute to the restoration of bone and articular tissue. The pathophysiological mechanisms underlying the cellular and subcellular effects of stimulation by an alternating electromagnetic field during the restoration of bone and articular tissue are considered. It was pointed out the several key signaling pathways involved in the restoration of bone and articular tissue under the influence of electromagnetic fields with an analysis of the potential for therapeutic application of electromagnetic fields alone or in combination with other available therapies.

Development of Technology for Processing Oil Sludge with Application of Super High Frequency Electromagnetic Fields


 
 
 This article considers the problem of processing and disposing of oil sludge of various origins. Large oil companies are concerned about the problem of incomplete processing of oil sludge. The most hazardous from an environmental point of view include oil sludge formed at all stages of oil production, transportation and refining. In recent years, oil-producing enterprises have introduced various technological solutions aimed at waste management into production, but there is no single method for processing oil sludge for the purpose of neutralization and disposal. All known oil sludge processing technologies by processing methods can be divided into the following groups: thermal - burning in open barns, furnaces of various types, obtaining bitumen residues; physical - burial in special cemeteries, separation in a centrifugal field, vacuum filtration and filtration under pressure; physical and chemical - the use of specially selected reagents that change the physical and chemical properties, followed by processing on special equipment; and biological - microbiological decomposition in the soil directly in storage, biothermal decomposition. Each of them, while having certain advantages, also has its drawbacks. For over 50 years, microwave heating technology has been used in industry. To present the advantages of this method, one needs to turn to the theory of microwave heating.
 Keywords: oil sludge, oil waste, influence of electromagnetic fields, water-in-oil emulsions
 
 

A REVIEW OF THE APPLICATION OF ELECTROMAGNETIC FIELDS ON MICROBES FOR SURFACE SANITARY WIPES.

The approach in the use of electromagnetic fields (EMFs) has shown antimicrobial effects in different frequencies and intensities. So far, different modalities of EMFs showed antimicrobial and antibacterial effects in different pathogens. However, a novel approach in the use of the EMFs on microbes was carried out using elaborate experimental set up. Apart from the inclusion of ionic pH medium, a short cylindrical pipe was inserted to a short iron core of the same concentric center to form a space in between. Void materials of glass pebbles activated charcoal and saline water (Gel) was filled to the space respectively in accordance with the three experimental set-ups. A coil of wire was inserted around the iron core with the terminals connected to a 12v rechargeable finger battery. These three novel EMFs approaches were conducted under normal prevailing temperature and each of the experimental set up was tested on a table surface infected with pathogens. The novel results showed that the destruction of microbes was 99.9% in faster and better than the prior methods. This results of these experiments will pave way for the optimal industrial application of EMFs to make surface sanitary wipe efficient and effective in Nigeria. Keywords: Electromagnetic Field. Surface Wipes, Microbes, Frequency, Radiation.

The application of high intensity and low intensity magnetotherapy in rehabilitation of patients with COVID-19 - a randomized controlled pilot study.

Background: rehabilitation of patients after severe pneumonia associated with the new coronavirus infection requires the searching for effective tools to restore impaired functions, including methods of hardware physiotherapy.
 Aims: to evaluate the effectiveness of the application of high-intensity electromagnetic field (HIEF) in rehabilitation of patients after pneumonia associated with COVID-19.
 Materials and methods: 40 patients were examined and treated at the outpatient stage of rehabilitation after severe pneumonia associated with COVID-19. All patients received a set of rehabilitation measures, including daily sessions of therapeutic exercises (No. 15) and magnetotherapy procedures (No. 15). Patients were randomly separated into 2 groups - 20 patients in the treatment group (TG) who received HIEF therapy (BTL-6000 Super Inductive System) and 20 patients in the control group (CG) who received low-intensity magnetotherapy (BTL-4000 Premium device).
 Results: during the course of therapy, there were no patients who dropped out of the study, and no undesirable side effects and complications were identified. The high clinical effectiveness of the complex of rehabilitation measures has been proven, more pronounced in the group of patients receiving HIEF therapy. The results were confirmed by reliable dynamics of clinical indicators according to the valid questionnaire and positive changes in spirometry data.
 Conclusions: application of high-intensity electromagnetic field (HIEF) is advisable in complex outpatient rehabilitation of patients after severe pneumonia associated with COVID-19 .
 Keywords: COVID-19, pneumonia, magnetotherapy, high-intensity electromagnetic field, physical and rehabilitation medicine.

Non-abrasive finishing of mating surfaces of machine parts

This article is devoted to the finishing technology of mating machine parts used in shut-off valves in various engineering industries. The method considered by the authors for obtaining high-precision surfaces without the use of abrasives allows one to achieve a decrease in labor intensity while ensuring a given resource of parts due to the use of combined processing methods with application of electromagnetic fields.

Non-abrasive Finishing of Mating Surfaces of Machine Parts Using Mixed Techniques with Electromagnetic Fields Application

In various branches of mechanical engineering, faucets, valves, gate valves and other shut-off devices are manufactured and used. Their main purpose is to regulate the flow rate and direction of flows of liquid and gas media. Features of such products in the aerospace and petrochemical engineering are special strict requirements due to the specificity of their operation. These include, for example, high pressure, resistance to aggressive, fire-and explosive environments, leaks of which are unacceptable according to safety rules and environmental legislation. The design of such products, as a rule, assumes high requirements for accuracy and roughness, especially at the interface of parts, high strength in case of impact pulse effects of the fluids in them. To ensure the above characteristics, finishing abrasive treatment is most commonly used, which can result in the effect of impregnation of the surfaces of products, which will negatively affect the useful life and performance indicators of the mating surfaces. At the same time, it is obvious that mechanical finishing without any use of abrasives is extremely difficult and time-consuming. The authors of the article suggest elimination of the negative effect of impregnation by means of mixed machining techniques with the application of electromagnetic fields. Purpose. The purpose of the work is to develop a technology for non-abrasive finishing of machine parts by developing a model that allows selection or calculation of the production modes of gapless mating parts of locking devices applied in various industries. Methods. The method of the research is the use of the scientific basis of mixed machining techniques, the theory of mass transfer in electrical machining, the fundamental foundations of mechanical engineering technology, modern methods for studying characteristics at the final stages of machining, modern measuring tools, special technological equipment, as well as computer technologies. Results. As a result of the research, new technique and devices were developed. This made it possible to implement a non-abrasive finishing operation of the mating surfaces of parts made of metal materials, the processing of which by mechanical methods is difficult. Conclusion. As a result of the conducted research, it became possible to obtain high-quality high-resource gapless locking products and to reduce labor intensity of the finishing operation up to 5 times and preparation for the production up to 2 times.

Exposure to non-continuous rotating magnetic field induces metabolic strain-specific response of Komagataeibacter xylinus

Application of electromagnetic field in biotechnological processes is considered a promising tool to enhance their effectiveness and to control microbe-derived synthesis of desired compounds. The current work analyzes impact of non-continuous rotating magnetic field (RMF) on ability of two Komagataeibacter xylinus strains to produce bacterial cellulose (BC) and to consume fructose and ethanol. Exposure of K. xylinus ATCC 53524 to the RMF of 50 Hz frequency resulted in a statistically significant 10 % increase in BC yield and significant drop of fructose consumption comparing to untreated control setting. In turn, K. xylinus ATCC 53582 cultures, under the exposure to the RMF, showed no significant improvement in BC production but higher level of fructose and ethanol utilization, comparing to RMF-untreated strain. Exposure to the RMF, regardless the Komagataeibacter strain scrutinized, increased the cell proliferation rate, which was reflected in greater cell density and viability as compared to the non-exposed cultures. The results of our study show potential of RMF to improve efficiency of BC production, but at the same time they indicate that aforementioned potential is strictly related to specific K. xylinus strain applied.

The study of thermostressed condition of the hydrogen quartz reactor during the methane pyrolysis

Based on analytical and numerical methods, the detailed studies of the temperature and thermostressed condition of quartz reactor intended for production of hydrogen by pyrolysis of methane passed through the molten tin, are performed. Heating of tin contained in the reactor is realized by the application of electromagnetic field generated by the inductor. The analysis of the study results allows concluding that the values of radial, circular and axial stresses during a uniform movement of the reactor along its height even in the most unfavourable conditions when the temperature drop along the wall of the quartz reactor is maximum and is equal to the difference of temperatures between molten tin and environment (ΔT ≈ 1500 °C) are within the tensile strength limit for quartz σ p = 50Mpa (5 kg / mm 2). In case of non-uniform heating of the reactor along its height observed at its partial filling with molten tin, in the area of transfer from the filled part of the reactor to its non-filled part, there are high axial temperature gradients, which result in temperature stresses exceeding the tensile strength limit. By using the obtained results, the recommendations connected with the reactor heating rate and essential for ensuring its safe operation have been developed.

Electromagnetic Effects on Solidification Defect Formation in Continuous Steel Casting

Understanding and reducing defects formed during continuous casting of steel are challenging because of the many inter-related, multiscale phenomena and process parameters involved in this complex process. Solidification occurs in the presence of turbulent multiphase flow, transport and capture of particles, superheat transport, and thermal–mechanical behavior. The application of electromagnetic fields provides an additional parameter to control these phenomena to reduce solidification defects. It is especially attractive because the field has the potential to be easily adjusted during casting to accommodate different casting conditions. This article briefly reviews how electromagnetic forces affect solidification defects, including subsurface hooks, particle capture, deep oscillation marks, depressions, cracks, breakouts, segregation, and shrinkage. This includes the related effects on superheat transport, initial solidification, surface quality, grain structure, internal quality, and steel composition distribution. Finally, some practical strategies regarding how to apply electromagnetics to improve steel quality are evaluated.

Bio-inspired polymeric iron-doped hydroxyapatite microspheres as a tunable carrier of rhBMP-2

Hybrid superparamagnetic microspheres with bone-like composition, previously developed by a bio-inspired assembling/mineralization process, are evaluated for their ability to uptake and deliver recombinant human bone morphogenetic protein-2 (rhBMP-2) in therapeutically-relevant doses along with prolonged release profiles. The comparison with hybrid non-magnetic and with non-mineralized microspheres highlights the role of nanocrystalline, nanosize mineral phases when they exhibit surface charged groups enabling the chemical linking with the growth factor and thus moderating the release kinetics. All the microspheres show excellent osteogenic ability with human mesenchymal stem cells whereas the hybrid mineralized ones show a slow and sustained release of rhBMP-2 along 14 days of soaking into cell culture medium with substantially bioactive effect, as reported by assay with C2C12 BRE-Luc cell line. It is also shown that the release extent can be modulated by the application of pulsed electromagnetic field, thus showing the potential of remote controlling the bioactivity of the new micro-devices which is promising for future application of hybrid biomimetic microspheres in precisely designed and personalized therapies.

Effect of the magnetotherapy in the regeneration after tenotomy in animals magnetotherapy in the regeneration

Background: The Achilles tendon is the largest and most resistant tendon in the human body, being one of the most common areas of overload injury among athletes. The rupture occurs more frequently in football athletes, running and jumping, because these activities cause a great stress on the tendon during eccentric muscle contraction of the sural triceps. Among the different physiotherapy resources used to repair tendon injuries, there is magnetotherapy, which is a feature that uses a pulsatile electromagnetic field, a suggested inducer of the acceleration of regeneration. Objective: To investigate the effects of magnetotherapy on the organization of collagen and elastic fibers and inflammatory process induced in different days and phases of the healing process of Achilles tendon injury in rats. Method: This study is a randomized controlled trial. Thirty female Wistar rats were randomly divided into 5 groups (each with n = 6), submitted to tenotomy by transverse shear in the middle third of the right Achilles tendon, except for group 1, which was control group without injury, sacrificed on day 14. Group 2, control with injury, sacrificed on day 7; group 3 was treated and received 5 pulsed electromagnetic field (PEMF) applications from 24h post injury and sacrificed on day 7; group 4, control with injury and sacrificed on day 14; and group 5 received 12 PEMF applications from 24h post injury and sacrificed on day 14. The parameters used were 20 mT, 50Hz and 30 minutes of application in each session, using the Magnetherp 330 digital device (Meditea). At the end of treatment, a histological study was performed to evaluate the amount of collagen and elastic cells and fibers and to compare the degree of organization of collagen fibers. Results: G - 3, compared to its control G - 2 showed lower acute inflammatory response; G - 5 did not show acute and chronic inflammation and possessed an accelerated process of repair without fibrosis, unlike its control. Conclusion: The magnetotherapy decreased the signs of inflammation in the acute phase, accelerated the repair process with the onset of fibrosis in 7 days; and at 14 days the tendon tissue was healed, with organizing fibrosis, without acute or chronic inflammation.

Frequency Dependent Alterations of S. Cerevisiae Proliferation Due to LF EMF Exposure

The presented paper deals with low frequency electromagnetic field application on Saccharomyces cerevisiae cells. Experiments performed through wide frequency range have shown selective frequency dependent biological response, which could be successfully predicted by ion parametric resonance theory proposed by V. V. Lednev. Although observed results give satisfying answer to questions whether or not electromagnetic fields could affect cell cultures even at non-thermal levels, the research presented herein opens a multitude of questions about the exact physical mechanisms underlying the observed microorganism behavior, as the theory discussed within the scope of this article is still not completely unambiguous.

Assessment of the effect of pulsed electromagnetic field application on the healing of bone defects in rats with heparin-induced osteoporosis

ABSTRACT Osteoporosis is a systemic skeletal disease characterized by an increase in bone fragility and fracture risk due to low bone mass and deterioration of bone tissue. Application of pulsed electromagnetic fields (PEMF), a non-invasive method with a low complication risk, is known to stimulate bone formation. The present study examines the histomorphometric and biochemical effects of PEMF application on the healing of bone defects in rats with heparin-induced secondary osteoporosis. Briefly, 12-month-old male Sprague-Dawley rats were examined in a prospective, randomized, single-blind study. Osteoporosis was induced by administering a daily dose of 2 IU/g heparin for 33 days. Bone defects were created on the right femur on Day 35. PEMF of an average intensity of 0.8 ± 0.2 mT and a frequency of 7.3 Hz, was applied for 1 h/day, for 28 days following surgery. Bone healing was evaluated by histomorphometric and biochemical analyses. The heparin + PEMF group displayed the largest amount of new bone area (P = .002) and the lowest mean CTx on Day 63 (P = .05). This study demonstrates that heparin administration leads to bone loss and osteoporosis, whereas the application of PEMF decreases this effect.

Application of electromagnetic field in anaerobic biodigestion in batch reactors

Anaerobic digestion processes with biogas production are widely used for organic waste treatment with an emphasis on energy recovery. Some recent studies have demonstrated the influence of magnetism on microbiological activity. These indicate a possible influence on the efficiency of anaerobic digestion. Thus, technologies that act in anaerobic digestion enhancement can contribute to the improvement of treatment of organic compounds. The present study aimed to verify the influence of a constant electromagnetic field on the anaerobic digestion in anaerobic reactors fed with glucose (2 g/L) at 37 ± 2 °C. In each experiment, reactors were operated with a constant electromagnetic field of 5, 7.5, and 10 mT. The inoculum was granular sludge from an anaerobic treatment plant in a non-selective media culture. Biogas production, chemical oxygen demand (COD), and solids removal were measured during the experiment. Results showed differences in methane production of 21.5% and in COD removal of 15% in the tests with an electromagnetic field of 7.5 mT. These results signs for the viability of the application of a constant magnetic field as a biostimulation agent.

Microstructure and wear resistance of electromagnetic field assisted multi-layer laser clad Fe901 coating

Thick Fe901 coatings were prepared on Cr12MoV substrates using electromagnetic field (EMF)-assisted multi-layer laser cladding. The effect of the EMF on surface topography, microstructure, multi-layer strategy, phase composition, and wear resistance in the multi-layer laser cladding Fe901 coatings were investigated. The results indicate that the application of EMF decreased the number of defects in coatings produced with laser cladding. Dendrites or cellular crystals oriented perpendicular to the interface were observed in the coatings with and without EMF-assisted growth. The microstructure of the coating formed with the applied EMF gradually transitioned from columnar dendrites to fine dendrites and equiaxed dendrites as the number of cladding layers increased. The coatings with and without an applied EMF primarily contained α-(Fe), α-(Fe,Cr), (Cr,Fe)7C3, CrFeB and FeCrMo phases. The EMF did not affect the phase composition of the coatings, although the intensity of X-ray diffraction peaks from the coating produced in an EMF were changed from those in the coating produced without the field. In addition, the coating produced in the EMF exhibited higher fatigue and abrasion resistance. The coatings prepared in an EMF also displayed narrower, shallower wear tracks, with 78.2% lower mass loss than the conventional coating.

Effect of electromagnetic field on water-in-oil emulsion and calcium carbonate crystallization

The investigation was devoted to the effect of electromagnetic field on crystallization of calcium carbonate, structure of CaCO3 crystals generated from oversaturated aqueous solutions, and water-in-oil emulsion (crude oil) properties. XRD demonstrated that electromagnetic field caused a decrease in mean size of CaCO3 particles by 30 μm and prevalent aragonite formation. We detected that electromagnetic field application leads to decreased apparent viscosity of water-in-oil emulsion and inhibits influence of a non-ionogenic surfactant on stability and viscosity properties of crude oil. As a matter of practice, the method demonstrated its efficiency to prevent scale deposits in oil production wells.

Dielectric behavior of single iron atoms dispersed on nitrogen-doped nanocarbon

We report the enhanced dielectric properties of iron atomically dispersed on nanocarbon. Theoretical simulations and calculations based on the Havriliak–Negami model and the first principles demonstrate that the increased dielectric property can be explained by the increased electrical conductivity and dielectric relaxations caused by the introduction of single iron atoms. Nanocarbon with single iron atoms exhibited enhanced electromagnetic wave absorption properties and could be further improved when being coupled with reduced graphene oxide. Our findings open a way for exploring high-performance materials with single metal atoms for practical applications in electromagnetic fields.

Effects and Mechanisms of Exogenous Electromagnetic Field on Bone Cells: A Review.

Osteoporosis, fractures, and other bone diseases or injuries represent serious health problems in modern society. A variety of treatments including drugs, surgeries, physical therapies, etc. have been used to prevent or delay the progression of these diseases/injuries with limited effects. Electromagnetic field (EMF) has been used to non-invasively treat bone diseases, such as fracture and osteoporosis, for many years. However, because a variety of cellular and molecular events can be affected by EMF with various parameters, the precise bioeffects and underlying mechanisms of specific EMF on bone cells are still obscure. Here, we summarize the common therapeutic parameters (frequency and intensity) of major types of EMF used to treat bone cells taken from 32 papers we selected from the PubMed database published in English from 1991 to 2018. Briefly, pulse EMF promotes the proliferation of osteoblasts when its frequency is 7.5-15 Hz or 50-75 Hz and the intensity is 0.40-1.55 mT or 3.8-4 mT. Sinusoidal EMF, with 0.9-4.8 mT and 45-60 Hz, and static magnetic field with 0.1-0.4 mT or 400 mT, can promote osteoblast differentiation and maturation. Finally, we summarize the latest advances on the molecular signaling pathways influenced by EMF in osteoblasts and osteoclasts. A variety of molecules such as adenosine receptors, calcium channels, BMP2, Notch, Wnt1, etc., can be influenced by EMF in osteoblasts. For osteoclasts, EMF affects RANK, NF-κB, MAPK, etc. We speculate that EMF with different frequencies and intensities exert distinct bioeffects on specific bone cells. More high-quality work is required to explore the detailed effects and underlying mechanisms of EMF on bone cells/skeleton to optimize the application of EMF on bone diseases/injuries. Bioelectromagnetics. 2020;41:263-278 © 2020 Bioelectromagnetics Society.

Combination of low intensity electromagnetic field with chondrogenic agent induces chondrogenesis in mesenchymal stem cells with minimal hypertrophic side effects

ABSTRACTBackground: There are different methods to develop in vitro neo-chondral tissues from adipose-derived stem cells (ADSCs). Application of electromagnetic field (EMF) on ADSCs is one of popular approaches, which results in chondrogenesis. If chondrogenic impact of EMF on ADSCs is supposed to be generalized as a protocol in translational medicine field, possible emergence of early or late hypertrophic maturation, mineralization and inflammatory side effects in chondrogenically differentiating ADSCs should be considered.Methods: The advent of chondrogenic and hypertrophic markers by differentiated cells under standard, platelet-rich plasma (PRP)-based or EMF treatments were monitored. Along with monitoring the expressions of chondrogenic markers, inflammatory and hypertrophic markers, VEGF/TNFα secretion, calcium deposition and ALP activity were evaluated.Results: Accordingly, treatment with %5 PRP results in higher GAG production, enhanced SOX9 transcription, lowered TNFα and VEGF secretions compared to other treatments. Although PRP up-regulates miR-146a and miR-199a in early and late stages of chondrogenesis, respectively, application of EMF + PRP down regulates miR-101 and -145 while up-regulates miR-140 and SOX9 expression.Conclusion: Comparing our results with previous reports suggests that presented EMF-ELF in this study with f = 50 Hz, EMF intensity of less than 30 mT, and 5% PRP (v/v), would facilitate chondrogenesis via mesenchymal stem cells with minor inflammation and hypertrophic maturation.Abbreviations: MSCs: mesenchymal stem cells; TGFβ: transforming growth factor-beta; PRP: platelet-rich plasma; ELF-EMF: extremely low-frequency electromagnetic fields; GAGs: glycosaminoglycans; ADSCs: adipose-derived stem cells; VEGF: vascular endothelial growth factor; TNFα: tumor necrosis factor alpha; ALP: alkaline phosphatase