Value Of Electric Field Intensity Research Articles

Schwinger correlation of Dirac fields in accelerated frames

We study the Schwinger correlation of Dirac fields in the noninertial frames under the influences of both constant and pulsed electric fields. We use both the entanglement negativity and quantum mutual information between particle and antiparticle as the indicator of the Schwinger correlation observed by the accelerated observers. We find that the Schwinger correlation in the inertial frames is the largest. With the increase of acceleration of the observers, the Schwinger correlation becomes smaller and smaller, but does not vanish in the limit of infinite acceleration. For the given acceleration, the Schwinger correlation is a nonmonotonic function of the electric field intensity, and there is an optimal value of electric field intensity for which the Schwinger correlation is the largest. In the case of pulsed electric fields, the Schwinger correlation is also the nonmonotonic function of pulsed width, which suggests the existence of optimal pulsed width for observing Schwinger correlation.

Study on electromagnetic dosimetry of the power cable in electric vehicle

To calculate the induced fields in the human body of the driver in an electric vehicle, the power cables of the electric vehicle are taken as the electromagnetic exposure source. The finite elements method is used to construct the electromagnetic environment model, which consists of the vehicle body, the power cables, and the driver body. The maximal values of the magnetic flux density inside the driver’s trunk and head are 4.63 μT and 0.12 μT, respectively. The maximal induced electric field intensity values are 670 mV/m and 99.7 mV/m, respectively. All values are below the safety limits of the ICNIRP. The results show that the electromagnetic environment induced by the power cables is safe for the driver. The study could provide a reference for improving electromagnetic exposure standards for electric vehicles.

Fabrication of a three-dimensional micro/nanocarbon structure with sub-10 nm carbon fiber arrays based on the nanoforming and pyrolysis of polyacrylonitrile-based jet fibers

To produce a three-dimensional micro/nanocarbon structure, a manufacturing design technique for sub-10 nm carbon fiber arrays on three-dimensional carbon micropillars has been developed; the method involves initiating electrostatic jetting, forming submicron-to-nanoscale PAN-based fibers, and maximizing the shrinkage from polyacrylonitrile (PAN)-based fibers to carbon fibers. Nanoforming and nanodepositing methods for polyacrylonitrile-based jet fibers as precursors of carbon fibers are proposed for the processing design of electrostatic jet initiation and for the forming design of submicron-to-nanoscale PAN-based fibers by establishing and analyzing mathematical models that include the diameter and tensile stress values of jet fibers and the electric field intensity values on the surfaces of carbon micropillars. In accordance with these methods, an array of jet fibers with diameters of ~80 nm is experimentally formed based on the thinning of the electrospinning fluid on top of a dispensing needle, the poking of drum into an electrospinning droplet, and the controlling of the needle–drum distance. When converting thin PAN-based jet fibers to carbon fibers, a pyrolysis method consisting of the suspension of jet nanofibers between carbon micropillars, the bond between the fibers and the surface of the carbon micropillar, and the control of micropillar spacing, stabilization temperature, and carbonation rate is presented to maximize the shrinkage from PAN-based fibers to carbon fibers and to form sub-10 nm carbon fiber arrays between three-dimensional carbon micropillars. The manufacturing design of a three-dimensional micro/nanocarbon structure can produce thin PAN-based jet nanofibers and nanofiber arrays aligned on micropillar surfaces, obtain shrinkage levels reaching 96% and incorporate sub-10 nm carbon fibers into three-dimensional carbon micropillars; these actions provide new research opportunities for correlated three-dimensional micro/nanocarbon structures that have not previously been technically possible.

The Effect of Body Mass Index on Tumor Treating Fields (TTFields) Intensity Distribution in the Lungs

Tumor Treating Fields (TTFields) therapy is a locoregional, noninvasive antimitotic cancer treatment modality. TTFields are electric fields that disrupt processes critical for cancer cell viability and tumor progression. They are generated by a portable medical device and delivered noninvasively to the tumor via two pairs of orthogonally placed transducer arrays. TTFields therapy is currently FDA-approved for recurrent and newly diagnosed glioblastoma and pleural mesothelioma, with ongoing studies in other solid tumor types including non-small cell lung cancer (NSCLC). In the phase 3 LUNAR study (NCT02973789), TTFields therapy demonstrated an improvement in overall survival when added to NSCLC standard of care. TTFields effectiveness depends upon several factors, including field intensity; thus, it is relevant to assess the impact of body mass index (BMI) on the distribution of TTFields in the lungs. This study utilized simulation-based approaches to assess the impact of BMI on electric field intensity distribution in the lungs. Three computerized female phantom models (with BMIs of 22, 26 and 30), were used to simulate electric field intensity. Two different arrays sizes (small [13 disks] and large [20 disks]) were applied to the thoracic region of the models. An electric field intensity distribution map for each model was generated, and electric field intensity values across the entirety of the lungs were analyzed. Electric field intensities were above 1 V/cm (amplitude), which is typically considered a sufficient level of TTFields dose to achieve a therapeutic effect, in all lobes in the lungs for all BMI models when large arrays were used. Therapeutic intensities were achieved in all lobes with the small arrays in all but one model (BMI 30), where intensities fell slightly below 1 V/cm in the right middle lobe. Results from this simulation-based study demonstrate that delivery of TTFields at therapeutic intensities is feasible even in patients with a high BMI, provided the appropriately sized array is used. These findings support ongoing clinical studies of TTFields therapy in lung cancer, including the recently completed LUNAR study in advanced NSCLC, and could facilitate optimization of therapeutic TTFields delivery to individual patients, based on their BMI.

Electric field and SAR distribution in the vicinity of dental implants exposed to the cell phone electromagnetic radiation

PurposeThe purpose of this paper is to determine the electric field and specific absorption rate (SAR) distribution within biological tissues in the vicinity of dental implants, exposed to the mobile phone radiation.Design/methodology/approachThis research was performed for the frequency of 2.6 GHz, which corresponds to 4G mobile network. The adequate 3D realistic numerical models of the mobile phone user’s head, dental implants and actual smartphone model are created using packages based on the finite integral technique numerical method.FindingsThe obtained results yield to a conclusion that the presence of dental implants affects the increase in electric field intensity and SAR values within biological tissues in its vicinity.Research limitations/implicationsThe presented procedure is limited to the 4G mobile network frequency of 2.6 MHz. The study should be extended to other mobile network frequencies to be more general.Practical implicationsThe criteria for selection of the materials used for dental implants production should be extended with the recommended material characteristics related to their influence on the electric field and SAR distribution, to keep their values in the limits prescribed by standards.Social implicationsThe obtained results provide the foundation for future research in mobile devices’ electromagnetic fields’ influence on human health.Originality/valueThe accurate determination of the electric field and SAR values within different biological tissues and organs in the vicinity of dental implants exposed to mobile phone electromagnetic radiation, demands highly realistic model of observed biological structures. For purposes of the current study, the procedure for modeling of highly nonhomogeneous structure with finite number of homogenous domains having known electromagnetic parameters is described in the paper. As a result, the 3D complex users’ head model formed of 16 homogeneous domains of different electromagnetic parameters is created.

Research on the Two-dimensional Electric Field on the Conductor Surface of 750 kV Transformer Substation under Different Structures

During the process of the design of the 750 kV transformer substation, the intensity of the electric field on the conductor surface is something very important. In this study, adopting a software of Finite Element Simulation, the authors respectively established simulation models of the distribution of two-dimensional electric field, calculated the maximum values of electric field intensity in different scenarios, and researched the distribution rules of electric field intensity on conductor surface in different wires, different division quantities, and different separation distances. As a result, the authors figured out the composition of wires which are applicable to the 750 kV transformer substation.

Inactivation of Contaminated Fungi in Rice Grains by Dielectric Heating

The quality of rice is decreased when contaminated with fungi. Aspergillus species are the most frequently found in rice. This research proposes using a dielectric heating method for fungal inactivation in rice grains by radio frequency (RF) energy. In order to understand the interaction between the fungi contaminating rice and electrical energy, dielectric properties comparison between Aspergillus sp. BP17 and rice powder were measured using an open-ended coaxial probe with a vector network analyzer (VNA) to develop dielectric heating equipment. The effect of RF energy on the dielectric heating system (9 kW, 40.68 MHz) is investigated based on different electric field intensities (150, 190, 225, 300, and 450 kV/m) with different temperatures (70, 80, 90, 100, and 110 °C). The growth of fungi contaminating rice was determined using a direct count method and reported as a percentage of inactivation. The result showed that the fungal inactivation of 100% was obtained at the electric field intensity value ≥ 225 kV/m at the lowest temperature of 90 °C. The combination of temperature and electric field intensity significantly (p ≤ 0.05) increased the percentage of fungal inactivation in rice grains. The optimal conditions of dielectric heating are suitable for fungal inactivation in rice industries. These results indicate that the proposed dielectric heating system is useful for inactivation of Aspergillus species.

Determination of Transmission Coefficient and Electric Field Distribution of Rice Husk/ Pcl Composites Using Finite Element Method for Microwave Devices

Material thickness is one factor that is considered in the selection of materials for usage in microwave applications. The demand for microwaves technology is widely needed in modern applications such as cellular telephone, satellite communication, radar system, global positioning system, and microwave remote sensing systems. Experiments and results abound for microwave properties determination for inorganic materials. Focus has recently been shifted to agricultural waste composite for microwave application. It is on this basis that this work primarily focuses on investigates microwave transmission coefficients and electric field visualization of different rice husk/PCL sizes placed inside a rectangular waveguide using the finite element method (FEM). Determination of the transmission coefficient for different thickness of rice husk/PCL composites were performed at X-band frequency using FEM. The thicknesses for the rice husk/PCL composites simulated were 10, 15, 20, 30, and 50 mm. The results of the simulation for the transmission coefficient revealed that the 50 mm composites had the lowest value of 0.148468 for the transmission coefficient at 12 GHz while the electric field visualization showed that the 50 mm composites have the least value of electric field intensity. The results confirms that the 50 mm thick sample absorbs the highest radiation. Based on the results obtained, all sample thickness can be used for microwave dummies.

Polarization analysis of THz radiation using a wire grid polarizer and ZnTe crystal

Objectives. Terahertz time domain spectroscopy (THz-TDS) is currently a promising research method in pharmacology and medicine due to the high sensitivity of terahertz radiation to the chemical composition and molecular structure of organic compounds. However, due to the chirality of many biomolecules, their analysis is performed by THz irradiation with circular dichroism. In particular, circular dichroism of THz radiation allows the study of “soft” vibrational movements of biomolecules with different chiralities. Therefore, when studying such biological materials, accurate control of THz radiation parameters is essential. The paper describes a method for characterizing THz radiation polarization on the example of a black phosphorus source material.Methods. The analysis of polarization parameters of THz radiation experimentally obtained by THz-TDS and using terahertz polarizers was performed by mathematical modeling of the interaction between THz radiation and a ZnTe crystal as a detector.Results. Two schemes of terahertz spectroscopy with the ZnTe crystal as the detector were discussed in detail. The polarization parameters were determined using one or two wire-grid THz polarizers. An expression for approximating the dependences of the peak-to-peak amplitude of THz radiation on the rotation angle of the wire-grid THz polarizer for these cases was derived. The impact of the terahertz electric field intensity value on the shape of polarization dependences was considered. The rotation angle of the polarization ellipse of THz radiation emitted by the surface of a bulk-layered black phosphorus crystal illuminated by femtosecond laser pulses was determined.Conclusions. The amplitude of the THz radiation electric field intensity begins to impact the shape of polarization dependences when its value becomes comparable to or exceeds 40 kV/cm.

Nonlinear thermo-elastic analysis of edge dislocations with Internal Heat Generation in Semiconductor Materials

In this work, the nonlinear thermo-elastic analysis of edge dislocations with internal heat generation is performed by the extended finite element method (XFEM) in semiconductor materials. The nonlinearity due to the temperature dependent electrical conductivity, thermal conductivity and thermal expansion coefficient is examined. The presence of an electric field in the direction of the dislocation line results in internal heat generation due to the electrical resistivity. The continuous Volterra model of dislocation is used for XFEM analysis of dislocations. The influence of Joule heat on thermal and elastic fields is observed. Different temperatures and electric field intensity values are taken for understanding the dislocation behavior. The Peach-Koehler (P–K) force for different dislocation configurations such as dislocation-dislocation interaction, dislocation-free surface interaction and dislocation-material interface interaction is evaluated. The results are found quite different with the amount of heat generation. The P–K force values are found more than that of pure elastic case. With the knowledge of the movability function, the obtained results can be used to predict the velocity of the dislocations.

Effects of electric and magnetic fields on dielectric and elastic properties of membranes composed of cotton fabric and carbonyl iron microparticles

This study investigates the influences of electric and magnetic fields applied both separately and superimposed on the dielectric and elastic properties of membranes (Ms) composed of cotton fabric and carbonyl iron microparticles (CI). To this end, three membranes were fabricated: one without CI microparticles and the remaining two with various proportions of CI microparticles. Additionally, scanning electron microscopy and energy emission X-ray spectroscopy were used to perform morphological and elemental analysis of the cotton fabric sample, CI microparticles, and the prepared Ms. Subsequently, flat capacitors (FCs) were manufactured using these Ms, encapsulated in a silicone rubber sheath. The FCs were introduced in static electric and magnetic fields superimposed over a sinusoidal electric field of frequency f = 1 kHz, and the electric capacity Cpand the tangent of dielectric loss angle Dpof the FCs were measured, depending on the E values of the static electric and magnetic fields superimposed over the medium-frequency electrical field. The values of the static electric field intensity and magnetic flux density were varied in steps of 4 kV/m within an interval 0 ≤ E (kV/m) ≤ 48 and in steps of 100 mT within an interval 0 ≤ B (mT) ≤ 300, respectively. Based on the obtained data, the components of the complex dielectric permittivity, those of the deformations, and the coefficients of elasticity of the Ms were determined to characterize the dependence of these values on the composition of Ms under the applied fields. Furthermore, the observed physical mechanisms were described based on the elements of physics of linear dielectrics and small deformation theory. Ultimately, the development of these materials can aid the design of various electrical devices for diverse applications such as sensors with electric field transducer, magnetic field, vibrations, and mechanical deformations.

The temperature state of a plane dielectric layer at constant voltage and fixed temperature of one of the surfaces of this layer

The paper formulates the nonlinear problem of steady‐state heat conduction at the constant electric potential difference on the surfaces of a plane dielectric layer with the temperature‐dependent heat conduction coefficient and electrical resistivity. A fixed temperature value is set on one of the layer surfaces, and the convective heat exchange with the ambient medium occurs on the opposite surface. The formulation of the problem is transformed to integral ratios, which allows the calculation of the temperature distribution over the layer thickness, governed by the monotonic and nonmonotonic functions. The quantitative assay of the temperature state of a layer of a polymer dielectric made of amorphous polycarbonate is given as an example and the analysis of nonuniformity of the absolute value of electric field intensity over the thickness of this layer.

Mapping of electric field intensity distribution in the 27 MHz - 3000 MHz frequency range in Diyarbakir city center

It is evident that the rapid development in science and technology has enabled various electronic devices and communication systems. However, there are also undesired effects of those devices on human health. One of those effects is the electromagnetic fields that exceeds the limits. Therefore, the electromagnetic fields emitted by the devices should not exceed a certain level. In that respect, different institutions around the world have determined the certain limits. One of the most important of these organizations in the world is the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Similar to the other existing organizations, the Information and Communication Technologies Authority (BTK) is the responsible authority in Turkey. In this study, electric field intensity values were measured using the drive test method with the Selective Radiation Meter (SRM-3006) device on the main streets in Diyarbakır City Center. Obtained measurement values were shown on dot thematic maps, two-dimensional maps and three-dimensional maps. As a result, locations with the highest electric field intensity were determined by these maps. In addition, the obtained results were compared with the limit values determined by ICNIRP and BTK and it was seen that the measured electric field intensity values did not exceed the exposure limits.

Mapping of electric field intensity distribution in the 27 MHz - 3000 MHz frequency range in Diyarbakir city center

It is evident that the rapid development in science and technology has enabled various electronic devices and communication systems. However, there are also undesired effects of those devices on human health. One of those effects is the electromagnetic fields that exceeds the limits. Therefore, the electromagnetic fields emitted by the devices should not exceed a certain level. In that respect, different institutions around the world have determined the certain limits. One of the most important of these organizations in the world is the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Similar to the other existing organizations, the Information and Communication Technologies Authority (BTK) is the responsible authority in Turkey. In this study, electric field intensity values were measured using the drive test method with the Selective Radiation Meter (SRM-3006) device on the main streets in Diyarbakır City Center. Obtained measurement values were shown on dot thematic maps, two-dimensional maps and three-dimensional maps. As a result, locations with the highest electric field intensity were determined by these maps. In addition, the obtained results were compared with the limit values determined by ICNIRP and BTK and it was seen that the measured electric field intensity values did not exceed the exposure limits.

Simulations and Experiments of the Soil Temperature Distribution after 2.45-GHz Short-Time Term Microwave Treatment

Microwave treatment is a green and pollution-free soil disinfection method. The application of microwaves to disinfect soil before cultivation is highly important to increase crop yields and protect the ecological environment. The electromagnetic field is an important parameter influencing the soil temperature field in the process of microwave soil treatment, and the change in soil temperature directly affects soil disinfection. Therefore, this article carried out research on the heating pattern in North China loess due to microwave treatment. First, COMSOL software was employed to simulate the microwave soil treatment process to analyze microwave penetration into soil. Second, with the application of microwaves at the designed frequency produced with a 2.45-GHz tunable microwave generating microdevice, soil with water contents of 0%, 10%, 20%, and 30% was treated for 10~60 s (at 10-s time intervals), and experiments on the influence of the microwave output power, treatment time, and soil moisture content on the soil temperature were performed via the controlled variable method. The simulation results indicate that with increasing soil moisture content, the microwave frequency inside the soil model increases, and the electric field intensity value decreases in the model at the same depth. After microwaves traverse through the 20-cm soil model, the incident field strength is three orders of magnitude lower than the outgoing field strength. The results of the microwave soil treatment experiment reveal that: (1) Compared to microwave output power levels of 1.8 and 1.6 kW, a level of 2 kW is more suitable for microwave soil disinfection. (2) After treatment, the highest temperature occurs on the soil surface, not within the soil. (3) The location of the highest soil internal temperature after microwave treatment increasingly approaches the soil surface with increasing soil moisture content, and the microwave output power does not affect the location of the highest soil internal temperature. Combining the electromagnetic field simulation and microwave soil treatment experiment results, it was found that the higher the field strength is, the higher the temperature value, and the highest soil internal temperature after microwave treatment often occurs at the first electromagnetic wave peak.

Modelling of a heavy-current intensively blasted electric arc at atmospheric pressure

The paper deals with intensively blasted electric arc burning in argon in a cylindrical channel of a designed experimental arc heater. The measured values of the arc current, the total voltage between a tungsten cathode and a grounded copper anode, the argon flow rate, and the water flow rates and temperature increments in individual parts of the arc heater characterize the operational conditions, but the parameters of the arc inside remain hidden. The simplified mathematical model has been designed to reveal the arc behavior in the arc heater channel, namely the arc radius and arc temperature development. The model is based on the energy and mass conservation laws and Ohm’s law and utilizes theoretically calculated transport and thermodynamic properties of argon altogether with the measured results as input data. Some simplifying assumptions are applied. A two-zone arrangement with a hot arc zone in the middle and a cold zone near the channel wall is supposed. The arc radius development along the arc heater’s channel is described by Schlichting’s formula for a free beam. Such combinations of three characteristic values of exponent n r, current density j 0 at the cathode tip, and arc temperature T A(s) at the end of the near-cathode layer are sought to enable as close as possible accordance between the computed and experimental data. Thereafter, a slight tuning of these parameters is needed to avoid extreme values of electric field intensity and temperature oscillations near the cathode while not to substantially worsen the reached agreement of measured and computed values. The functionality of the model is demonstrated using four typical sets of experimental data.

Study on Measurement Error of Power Frequency Electric Field Intensity Caused by Change of Air Dielectric Constant with Humidity

People are paying more and more attention to the influence of power frequency electric field on their living environment, so the measured value of power frequency electric field under AC transmission line becomes an important reference for judging whether the surrounding environment is polluted or not. In actual measurement, it is found that the measured value of electric field intensity in high humidity areas is often relatively large. This paper will investigate the influence of the change of air dielectric constant on electric field measurement. Through experiments and simulations, it is found that air dielectric constant increases with the increase of humidity, which increases rapidly before the ambient humidity reaches 75%, and increases slowly after the ambient humidity exceeds 75%. However, it was found by simulation that the change of air dielectric constant has no obvious influence on the surrounding electric field intensity. Therefore, the change of air dielectric constant is not the main factor leading to relatively large measured value of field intensity in high humidity areas.

Enhanced light absorption in monolayer tungsten disulfide with dielectric Bragg reflector and metallic thin film

A multi-layer structure based on the microcavity effect of a dielectric Bragg reflector (DBR) and metallic thin film to enhance light absorption of monolayer tungsten disulfide (WS2) is proposed. This structure is combined with a cover layer and a spacer layer to adjust the phase-matching condition. The transfer matrix method (TMM) was used to study its optical transport characteristics. It was found that the microcavity effect of DBR and the metallic thin film forms a maximum value of electric field intensity near the monolayer WS2, which effectively promotes the light-matter interaction in monolayer WS2. As the thicknesses of the spacer layer and cover layer were comprehensively optimized, the light absorption of monolayer WS2 at the wavelength of 611 nm reached 94.38 % and the full width at half maximum (FWHM) is only 9 nm. Furthermore, the effect of DBR periodicity and angle of incidence on the light absorption of monolayer WS2 were discussed. The research presented here confirms that changing the above structural parameters can effectively regulate the absorption peak wavelength and maximum value of monolayer WS2. The results of this study provide new ideas for the preparation of high-performance monolayer WS2 photodetectors and other new optoelectronic devices.

Electric field simulation of Ag nanoparticles induced by Femtosecond laser in welding process

The electric field distribution of Ag nanoparticles under femtosecond laser is simulated by solving Maxwell equations in this article. The results show that with the same laser energy, the coupling electric field between adjacent nanoparticles becomes stronger and stronger as the spacing between nanoparticles decreases, while the enhancement factor decreases rapidly when the spacing between nanoparticles is less than 1 nm, because under this condition, its mechanism includes not only the coupling of two dipoles, but also the electron tunneling between two surfaces. Besides laser energy, the electric field of Ag nanoparticles is greatly affected by the nanoparticles size and their spatial distribution. With the same laser energy and spacing, the smaller the particle size, the higher the peak value of electric field intensity, but the faster the attenuation with distance. In the polarization direction of the laser, the enhancement factor of the electric field is more obvious. When the laser acts on several Ag nanoparticles, the electric field of nanoparticles in the range of spot size is quite different from that of the nanoparticles outside the spot.

Novel wireless power transmission based on Maxwell displacement current

Abstract Wireless power transmission (WPT) is vitally important for portable electronics. Recently, wireless energy delivery via Maxwell displacement current from triboelectric nanogenerator may open new routes to develop novel technologies especially for implantable medical devices and sensor network due to its flexibility, adaption, convenience and safety. In this paper, the propagation characteristics of WPT are explored, which are based on displacement current from a spherical high frequency electric field. The results showed that the spherical surfaces with the same radius from the center have equal value of electric field intensity. When the receiver has a larger area or workload, the output has a higher value, which is subject to the electric field intensity. However, the current is almost unchanged with increasing output power below 15 kΩ of load resistance in series, which may have potential applications for sensors. Furthermore, the receiver circuit of wireless energy is in accordance with the traditional serial and parallel circuit regularity. Based on these, we are going to assume that the electric field source is a reservoir, and water flow is analogous to current. The assumption is suitable for studying propagation characteristics. This new discovery may also offer a new research direction for WPT based on Maxwell displacement electric field.