Use Of Electromagnetic Energy Research Articles

Insights into Civilian Electromagnetic Absorption Materials: Challenges and Innovative Solutions

AbstractThe emergence and widespread adoption of fifth‐generation wireless technology in civilian sectors have advanced the information revolution, while simultaneously leading to a variety of negative impacts. Foremost issues in the civilian domain include electromagnetic (EM) pollution, interference, and the inefficient use of EM energy. Despite growing global awareness, progress in devising effective solutions is sluggish, underlining the complexity of these issues. The delay in addressing EM concerns arises from several factors, including a considerable gap in comprehensive understanding and the absence of a unified stance on these critical issues. Moreover, the emergence of new challenges like EM interference and energy inefficiency indicates a clear need for innovative ideas and approaches. Addressing these civilian issues extends beyond the inherent properties of EM absorbers, requiring combination of tailored macro‐structural designs and external energy field management for a comprehensive solution. This situation emphasizes the urgent need for diverse strategies and creative thinking to navigate the challenges posed by the civilian EM issues. This perspective underscores these identified challenges and systematically proposes practical approaches to each, aiming to foster both conversation and action in this crucial area. The insights provided are expected to substantially aid in confronting and alleviating these pressing EM concerns.

Quality of Soybean Seeds after Microwave Drying

The use of electromagnetic energy for drying seeds has been shown to be a promising alternative. However, studies show that the technique still lacks careful evaluation due to the sensitivity of soybean seeds to damage caused using microwaves. Studies have shown that the use of microwaves during drying can be safe in seeds of soybeans, corn, and beans, among others. These studies recognize that drying using microwaves has a great potential for savings in the drying process, as it considerably reduces the drying time. This work aimed to evaluate the immediate damage caused in soybean seeds subjected to drying at temperatures of 40, 50, and 60 °C, with power of 0, 0.5, and 1 W/g at a frequency of 2.45 GHz. The results of the vigor and germination tests showed that the action of microwaves on seeds was not only safe and more efficient but also brought about increases in seed germination and vigor. However, the process must be judicious and obey precise indices of power and temperature to not cause damage to the seeds.

Calculation of temperature distribution in heavy oil reservoirs by electromagnetic heating

The introduction of heat into a reservoir has proven to be an effective way to reduce the viscosity of heavy oils by increasing the temperature in the formation. The use of electromagnetic energy has proven to be particularly attractive because of its advantages vis-à-vis conventional heat recovery techniques. While extensive research has been conducted on this radiofrequency recovery method over the years, numerical simulation with reservoir industry applications has been rarely used for electromagnetic heating with heavy oil reservoirs when connected to strong-bottom aquifers. We propose a numerical scheme to estimate temperature variations in the reservoir by electromagnetic absorption, based on the calculation of the electro- magnetic wavefield amplitude and radiation heat diffusion coupling. The electrical and thermal properties of the reservoir were calculated considering the fractions and saturation of its phases. The results obtained from this RF heating simulation show a radially distributed temperature profile within the reservoir. The power and frequency of the incident wave were considered for an antenna located in the center of the formation. This allows to determine the required energy in kWh, and its influence on the antenna power, as well as the thermal and electrical properties of the medium such as aquifers. Numerical modelling allows reaching a stable temperature inside the reservoir, in days or months, despite the strong presence of water-saturated zones. The simulation shows that the presence of aquifers at bottom and partially saturated media affects reservoir heating. To make the numerical experiment reproducible and verifiable, the workflow is provided in code form.

Ground penetrating radar applications and implementations in civil construction

ABSTRACT The ability to evaluate civil structures without altering or damaging the materials is becoming increasingly important and useful for the maintenance of infrastructure. The technique to analyze and test materials for weaknesses without causing destruction is referred to as non-destructive evaluation or testing. Specifically, a common method of this type of inspection is called ground penetrating radar (GPR), which is desired in many construction applications. With use of electromagnetic energy, GPR has the capability to locate buried objects in materials because of the differences in electrical and magnetic properties that are encountered. Valuable data can be obtained on these subsurface objects, allowing for an understanding on the properties and making proper judgment on the structure possible. This study explores the approaches in which GPR has been implemented for the assessment of the following structures: pavement, reinforced concrete, railway ballast, soil and buried pipes. Through different data acquisition and processing techniques, results show that there is great success when using GPR for collecting information for verifying the state and condition of these materials.

The prospects for radiofrequency electromagnetic fields control approaches improvement under 5G wireless communication technologies introduction

5G mobile communication system networks improvement leads to scenarios for the use of electromagnetic energy in various sectors of the economy variety increase and radiofrequency electromagnetic fields (EMF) person’ exposure with expansion of the exposed by occupational and non-occupational exposure contingent including. Base station EMF distinctive feature is its complex frequency-time and spatial dynamics with constant control signals that should be taken into account in modern EMF control methods. International practice in case of cellular base stations EMF assessment uses maximal values determination: theoretical and actual levels. EMF theoretical maximal values characterize base station operation mode under highest network load, highest data traffic and time-frequency radio channel resource full usage at the maximum permitted transmission power. Actual maximum EMF levels determination approach is base stations EMF evaluation alternative principle and is based on practically achievable maximum EMF emission, stochastic nature of base station signals with taking into account. The approaches to statistical assessment of actual maximum exposure levels are becoming a priority for international practice of base station EMF assessment and control due to adaptive antenna technologies in 5G cellular networks development. This approach to realistic EMF exposure assessment is fundamentally new for Russian practice and will require methodological updating of regulatory framework as well as comprehensive researches with network operators, including approaches to selective measurement results extrapolation for implementation. Ethics. The study did not require the ethics committee conclusion.

Studies on Potential of Magnetic Field Applications for Sustainable Agriculture

As per the reports published by Ministry of Water Resources GOI, increasing salinity of soil in Punjab is becoming threat to sustainability. There is an urgent need to reduce the rate of salt accumulation and improve the leaching of salts below root zone, make use of low-quality saline water and at the same time to increase the rate of germination of seeds and crop yield without leading to detrimental effects on environment.Present study is aimed around use of electromagnetic energy for the change in the saline behaviour of water, for the investigations a characteristic sample of saline water of EC = 4000 μS/cm was magnetized by passing through a pipe fitted with 4 pairs of electromagnets, at flow rate of 2L, 3L & 4L per minute, with varying magnetic field strengths of electromagnet, by varying applied voltage of 2V and 4V. Surface Tension of differently magnetized saline water was observed by Stalagmometer drop count method. The rate of accumulation of salts in terms of EC of soil at 30 cm, 60 cm & 90 cm depths in soil was compared by irrigating soil in two 1m long vertical columns with saline water and Magnetically Treated Saline Water (MTSW) for 5 irrigations.Effect of magnetically treated normal and saline water and Magnetic Field (MF) was also observed on seed germination and plant growth of Vigna radiata. It was observed that not only MF in soil but also magnetically treated normal & saline water have facilitated the growth which can be attributed to increased absorption of water and nutrients if treated magnetically.

Magnetization of ferromagnetic charge at induction heating

The article presents analysis of magnetization and heating of ferromagnetic charge in crucibles of induction furnaces of two types. In inductor furnaces, the charge is magnetized by a vertical electromagnetic flow, and in electromagnetic furnaces with a curved U-, C-, or O-shaped magnetic circuit (MPr) – by a horizontal flow. Knowledge of these largely general magnetization processes is insufficient. Bi magnetic induction in charge material is rather important. There are difficulties in determining this parameter during magnetization of a single piece of charge and other magnetic quantities associated with it: Bm induction and Nm strength of the demagnetizing field, N demagnetization coefficient, M magnetization, magnetic permeabilities of μi substance and μt body, km susceptibility, etc. Difficulties increase at magnetization, if it is a porous body with crucible volume of ~V t and a factor of filling with ferromagnetic pieces of this volume of Kv ≤ 0.5. It also creates a demagnetizing field with Bmt induction and Hmt strength. Beyond that, pores have an additional demagnetizing effect. Therefore, the induction Вiт in a porous body is less than the induction Вi in a solid one. To compare magnetization of ferromagnetic charge with horizontal and vertical flows with frequency of 50 Hz, modeling experiments were carried out with the samples of DSL08 unconsolidated shot from high-carbon steel (GOST 11964 – 83) with Kv ≈ 0.53. The samples were placed in the inductor and between the poles of a U-shaped core piece. Induction was measured by a cylindrical and flat probe unit of Sh1-15 militeslameter in air and in the sample. An advantage of electromagnetic furnace over an inductor one is more uniform distribution of Bi induction in charge and its significant excess (1.7 times) over the Be induction in a furnace working cavity, which indicates more efficient use of electromagnetic energy in this furnace during heating. The author proposed to control Вi induction when heating the charge by the ammeter-voltmeter method using measuring coil made of heat-resistant wire.

Extraction of Heavy Metals From Polluted Waters with Adsorbents and Phytosorbents

The work presents data on a study of extraction o.f heavy metal ions (Zn 2+ , Cd 2+ , Pb 2+ , Cu 2+ ) from wastewaters with a combined sorption material (SM) based on a mixture of waste of ceramic industry and agriculture (threshing millet, husks of sunflower or wheat). Moreover, tertiary treatment of wastewater was conducted by phytososbents – common duckweed Lemna minor and eichornia Eychornia. It is established that effectiveness of the treatment of wastewaters with the combined SM from the heavy metals cations is 94-99 %. Acceleration of the phytoremediation achieves by the way of use of electromagnetic energy (constant magnetic field, ultraviolet and laser radiation).

마이크로파가 인가된 화염에서의 화염안정성 및 오염물질 배출특성

The use of electromagnetic energy and non-equilibrium plasma for enhancing ignition and combustion stability is receiving increased attention recently. The conventional technologies have adapted the electrical devices to make the electromagnetic field, which resulted in various safety issues such as high-maintenance, additional high-cost system, electric shock and explosion. Therefore, an electrodeless microwave technology has an advantage for economic and reliability compared with conventional one because of no oxidation. However, the application of microwave has been still limited because of lack of interaction mechanism between flame and microwave. In this study, an experiment was performed with jet diffusion flames induced by microwaves to clarify the effect of microwave on the combustion stability and pollutant emissions. The results show that microwave induced flames enhanced the flame stability and blowout limit because of abundance of radical pool. However, NOx emission was increased monotonically with microwave intensity except 0.2 kW, and soot emission was reduced at the post flame region.

Radio Frequency Powering of Microelectronic Sensor Modules

Abstract In RFID applications the power supply of transponders via electromagnetic field is state-of-the-art. In this presentation the use of electromagnetic energy will be discussed for the operation of sensor modules. Starting with the question, whether the omnipresent radiation from power supply networks, radio transmitters, and mobile phone base stations is useable (energy harvesting), the feasibility of the operation of self-sufficient sensor modules is explained. Ancillary conditions of typical applications (e. g. operating range) and technology are considered.

Waveguide monitoring (such as sewer pipes or ocean zones) via matched field processing

Detecting and locating changes in a waveguide can be extremely difficult. A method is suggested here which does not require simplification of the problem (no spherical chickens) nor any modeling of the waveguide nor of the propagation within it. The method relies only on previous broadband data recorded on an array of receivers (two or more) which is then compared to more recent data to investigate change. Backscattered energy is to be examined here although bistatic configurations may also be possible. This approach is applicable whenever there is sufficient, appropriate data for comparison (note that absolute levels are not needed) and can be applied to acoustically search for scatterers introduced to an ocean zone (such as targets or pollutants), blockages or changes in sewer pipes, or even to non-acoustic energy in a waveguide, e.g., the use of electromagnetic energy in the earth-ionosphere waveguide. This method is based on the signal processing technique known as matched field processing and will be demonstrated on a variety of laboratory sewer pipe data. The method (particularly for localization) is introduced here, as is the suggestion for application to general waveguide environments.

The effects of prenatal and neonatal exposure to electromagnetic fields on infant rat myocardium

IntroductionElectromagnetic fields (EMF) have adverse effects as a result of widespread use of electromagnetic energy on biological systems. The aim of this study was to investigate the effects of prenatal exposure to EMF on rat myocardium by biochemical and histopathological evaluations.Material and methodsIn this study, 10 pregnant Wistar rats were used. Half of the pregnant rats were exposed to EMF of 3 mT, and the other half to sham conditions during gestation. After parturition, rat pups in the 5 EMF-exposed litters from birth until postnatal day 20 were exposed to EMF of 3 mT for 4 h/day (EMF-exposed group, n = 30). Rat pups in sham litters from birth until postnatal day 20 were exposed to sham conditions (sham group, n= 20).ResultsIn the EMF-exposed group, lipid peroxidation levels significantly increased compared to sham. Superoxide dismutase activities decreased significantly in the EMF-exposed group compared to sham. TUNEL staining showed that the number of TUNEL-positive cells increased significantly in EMF-exposed rats compared with sham. Under electron microscopy, there were mitochondrial degeneration, reduction in myofibrils, dilated sarcoplasmic reticulum and perinuclear vacuolization in EMF-exposed rats.ConclusionsIn conclusion, the results show that prenatal exposure to EMF causes oxidative stress, apoptosis and morphological pathology in myocardium of rat pups. The results of our study indicate a probable role of free radicals in the adverse effects of prenatal exposure to EMF. Further studies are needed to demonstrate whether the EMF exposure can induce adverse effects on the myocardium.

PHYSICAL METHODS IN AGRO-FOOD CHAIN

Chemical additives (fertilizers and plant protection preparations) are largely used for improving the production yield of food produce. Their application often causes the contamination of raw materials for food production, which can be dangerous for the health of consumers. Alternative methods are developed and implemented to improve and ensure the safety of on-farm production. The substitution of chemical fertilizers and soil additives with alternative treatment methods, such as irradiation, ultrasound and the use of electromagnetic energy are discussed. Successful application of physical methods in different stages of food-preparation is recommended.

Stability analysis of optofluidic transport on solid-core waveguiding structures

Optofluidic transport involves the use of electromagnetic energy to transport nanoparticlesthrough the exploitation of scattering, adsorption and gradient (polarization) basedforces. This paper presents a new approach to stability analysis for a system ofbroad applicability to such transport, namely the optical trapping of dielectricparticles in the evanescent field of low index (polymer) and high index (silicon)solid-core waveguide structures integrated with microfluidics. Three-dimensionalfinite element based simulations are used to determine the electromagnetic andhydrodynamic field variables for the system of interest. The net force acting onparticles is determined through evaluation of the full Maxwell and flow shearstress tensors, and a trapping stability number is obtained by comparing the workrequired to remove a particle from the waveguide with available random thermalenergy. These forces are correlated to controllable experimental parameters such asparticle size, fluid velocity, and channel height, and a series of trapping stabilitydiagrams is produced which detail the conditions under which optofluidic transport ispossible.

Foam Sclerotherapy for the Treatment of Varicose Veins

Treatment of venous insufficiency with liquid sclerotherapy is considered by some to be an unfulfilled promise. It was heralded in the first half of the last century to be a replacement for surgery, but as recurrences of varicose veins appeared in limbs treated with injection techniques, surgery reappeared and was dominant in the last half of the century. Just as saphenous stripping was proved to be superior to proximal ligation, both were replaced by use of electromagnetic energy, such as radiofrequency and laser venous ablation, as a means of taking the saphenous veins out of the circulation. Now reports of recurrent varices in 20 to 50% of operated cases are making some physicians look to alternatives in treating varicose veins. Foam sclerotherapy must be looked upon as an entirely new method of treatment. It is useful in all types of varices and is proven to be safe, simple, cheap, reliable, and repeatable.

Microwave Convective Drying and Storage of Soy-Fortified Paneer

Drying of acid-coagulated protein-rich food products by conventional methods produces insurmountable problems like formation of a moisture-retaining crust, longer drying time, poor rehydration characteristics and oiling off during drying. These problems can be minimized by the use of electromagnetic energy for drying because of its rapid and uniform dissipation. The use of microwaves for drying of soy-fortified paneer (SFP) has been explored in the present study. The effect of microwave convective drying variables such as hot air temperature and microwave power levels on drying rate and diffusivity were analysed. Both the drying rate and diffusivity increased with increase in hot air temperature and microwave power level. A hot air temperature of 53:5°C and microwave power of 111:5W gave good-quality dried SFP cubes of uniform texture and surface, unblemished and with clear color. The dried SFP cubes rehydrated well and had a shelf life of 118 days under accelerated storage conditions (38 ± 2°C, 90% relative humidity).

Radio-frequency electromagnetic fields associated with cellular-radio cell-site antennas.

Because of a heightened public awareness of issues pertaining to the use of electromagnetic energy, concurrent with a rapid growth of the cellular telephone industry, a study was initiated to characterize the electromagnetic environment associated with typical cell-site antennas. In particular, the radio-frequency electromagnetic (RF) fields in the vicinity of several antenna towers, ranging in height from 46-82 m, were characterized by measurement. In all cases, the antennas were omnidirectional co-linear arrays. The maximal power densities considered representative of public exposure were found to be less than 100 microW/m2 (10 nW/cm2) per radio channel. Comparison of measured values with the corresponding values that were calculated from the free-space transmission formula indicated that the analytical technique is conservative (i.e., overestimates field levels). The measured and corresponding analytical values were found to be well below accepted exposure limits even when extrapolated to simultaneous and continuous operation of the maximal number of transmitters that would be expected to be installed at a cell-site. Additional measurements were made in the near field of the same antenna type in a roof-mounted configuration. At a distance of 0.7 m from the antenna, the maximal power density in the main beam was found to be less than 30 W/m2 (3 mW/cm2) when normalized to sixteen radio channels (the maximal number used on a single antenna) and less than 30 mW/m2 (3 microW/m2) at 70 m. In all cases, the effective radiated power (ERP) by each radio channel was 100 W referenced to a half-wave dipole. This paper describes the instrumentation and measurement techniques used for this study and provides a summary of the results.

Electromagnetic energy and food processing.

The use of electromagnetic energy in food processing is reviewed with respect to food safety, nutritional quality, and organoleptic quality. The effects of nonionizing radiation sources such as microwave and radio-frequency energy and ionizing radiation sources, e.g. radioactive cobalt-60 and caesium-137, on the inactivation of microbes and nutrients are compared with those of conventional heating processes both in terms of their kinetic behavior and their mechanisms of interaction with foods. The kinetics of microwave and conventional thermal inactivation are considered for a generalized nth-order model based on time and temperature conditions. However, thermal inactivation effects are often modeled by 1st-order kinetics. Microbial and nutrient inactivation by ionizing sources are considered for a 1st-order model based on radiation dose. Both thermal and radiation resistance concepts are reviewed and some typical values of radiation resistance are given for sensitive vegetative bacterial cells, yeasts, and molds and for resistant bacterial spores and viruses. Nonionizing microwave energy sources are increasingly used in home and industrial food processing and are well-accepted by the American public. But, despite recent Food and Drug Administration approval of low and intermediate ionizing radiation dose levels for grains and other plants products and the fact that irradiated foods are sold in more than 20 countries of the world, public fears in the U.S. about nuclear energy may limit the role of ionizing radiation in food processing and preservation and may also limit the use of nuclear fuels as an alternate source of electrical energy.

A proposal for searching for electromagnetic wave sources by using a synthetic aperture technique

AbstractUnwanted electromagnetic waves radiated from equipment making use of electromagnetic energy create numerous societal problems. The prevention of these problems has been studied extensively. In this paper, a method for estimating the location of the unwanted electromagnetic waves is studied. Since it is difficult to make the antenna aperture large especailly at low frequencies, a search for electromagnetic wave source via a synthetic aperture technique is proposed. In the estimated electromagnetic source distribution by this method, images similar to the antenna sidelobes appear. It is demonstrated by computer simulation that the images can be suppressed by use of the synthetic aperture method with subarrays or use of Mill's cross method. Discrepancies between the true source location and the estimated location have been found in regard to the synthetic aperture length and the geometrical relationship with respect to the aperture center. It has been found that the antenna configuration with the synthetic aperture length of 10 λ can estimate an electromagnetic wave source within 10 λ square with accuracy of less than 1/4 λ square. Therefore this method is sufficiently practical if the location of the source is restricted somewhat.

Induction of deep, local hyperthermia by ultrasound and electromagnetic fields: problems and choices.

The feasibility, and the biophysical and engineering concepts underlying the use of electromagnetic energy and ultrasound for production of deep, local hyperthermia are discussed. Focused ultrasound currently is the only modality that can be used for producing controllable levels of hyperthermia localized to deep seated tumors, non-invasively and safely. The ultrasonic focus needs to moved within the tissues around the periphery of the tumor to achieve uniform temperature distributions.