Source Of Electric Field Research Articles

Chiral motion in colloidal electrophoresis.

Asymmetrically charged, nonspherical colloidal particles in general perform complex rotations and oblique motions under an electric field. The interplay of electrostatic and hydrodynamic forces complicates the prediction of these motions. We demonstrate a method of calculating the body tensors that dictate translational and rotational velocity vectors arising from an external electric field. We treat insulating rigid bodies in the linear-response regime, with indefinitely small electrostatic screening length. The method represents the body as an assembly of point sources of both hydrodynamic drag and surface electric field. We demonstrate agreement with predicted electrophoretic mobility to within a few percent for several shapes with uniform and nonuniform charges. We show that even symmetric shapes can have strong chiral twisting motions. The method applies more generally to active colloidal swimmers.

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.

Mechanisms of the Electric Field-Induced Displacement and Transformation of Magnetic Domain Boundaries

A study is made of the magnetoelectric interaction between an electric field source and a magnetic domain boundary (DB) in a film of a magnetic dielectric with easy magnetization axis anisotropy. A coordinate dependence for the potential DB energy on the distance between the electric field source and the domain boundary is plotted. A potential minimum for DB is shown to occur at the source location. The dependence of the linear density of the electric charge of the magnetic DB on the electric field magnitude and the electrode size is studied with regard to the electro-induced rearrangement of the micromagnetic structure.

Statistical study of geomagnetic storm effects on the occurrence of ionospheric irregularities over equatorial/low-latitude region of Africa from 2001 to 2017

The effect of Coronal Mass Ejection (CME) and Corotating Interaction Region (CIR)-driven storms on the occurrence of ionospheric irregularities (OIIs) over the African equatorial and low-latitude region are studied statistically for the first time. In addition to the CME and CIRs’ catalogs, we have used the disturbance storm time (Dst) ≤ -30 nT and Kp ≥ 3 to identify the storm periods. The study was based on Global Navigation Satellite System (GNSS) total electron content (TEC) observation from three stations (nklg: 8.05°S, 81.05°E; mbar: 10.22°S, 102.36°E; and nazr: 0.25°S, 111.01°E, Geomagnetic) during 2001–2017. Based on the GNSS observations, the rate of change of total electron indices (ROTIROTI and ROTIave) have been used to observe the presence/absence of ionospheric irregularities. To examine the effect of the storms on the OIIs, ratio of ROTIave of the selected storm period to the quiet monthly mean of ROTIave, ROTIratio=ROTIobs/ROTI‾quiet, was applied. Based on our analysis, ROTIratio≥3.2, ROTIratio≤0.16 and 0.16<ROTIratio<3.2 were identified as threshold values indicating the enhancement (EN), suppression (SP), and no significant (NE) effect of the storms on the OIIs, respectively. Our results revealed that the SP in the OII during CME-and CIR-driven storms are more prevalent than the EN. During both CIR-and CME-driven storms, the percentage occurrence rate in EN observed over nklg was greater than mbar and nazr. Most of the SP effect of the storms, on the other hand, was predominantly observed over nazr and mbar stations. The occurrence rate of EN, SP and NE effect of both CME-and CIR-driven storms show dependence on the local time at which large decrease in Dst occurs. We also found that SP effect of both CIR-and CME-driven storm show a positive and linear correlation with sunspot number (SSN). While the EN effect of CIR-driven storm show a negative and linear relation with SSN, CME-driven storm effects show weak relation. The polarity and amplitude of different sources of disturbance electric field observed in the evening hours could play a dominant role in affecting the OIIs. The difference in the seasonal variation in the occurrence rate of EN, SP and NE effect of the storms observed over different stations were also discussed.

ІНТЕРПРЕТАЦІЙНІ МОЖЛИВОСТІ ЕЛЕКТРИЧНИХ ПОЛІВ ДЖЕРЕЛ ДИСКОВОГО ТИПУ

As a result of aging of the protective insulation layer of underground pipelines, which occurs under the influence of external factors, in the insulating protective layer can form places where the insulation is damaged that cause a leakage of electric current under the protective potential of the pipe. These processes lead to a decrease in the protective potential of underground pipelines, and thus to a deterioration in the protection of underground utility system. Such damage locations are recorded by surveying the distribution of the electric potential "soil-pipe" (Usp) along the pipeline route by the remote electrode and measuring the "transverse and longitudinal gradients" of the electric field. Since the places of electric current leakage are sources of electric fields, it is important to know the features of these fields in order to assess the degree and extent of damage. From a fundamental point of view, this question comes down to solving the inverse problem of electrometry for fields created by different structure sources. In the case of detailing anomalies, it is desirable to obtain electrometric survey data with an accuracy that allows to apply for their quantitative interpretation methods that base on analytical relationships for anomalies of these parameters. In this paper there is an analysis of the possibilities of using methods which is appropriate for fields created by point sources to interpret the anomalous field caused by a source of leakage current of the disk type damage.

High voltage designed and pulsed electric field circuit using standard sphere-gap method

The circuits designed of the high voltage pulsed source using the sphere-gap as switching and will be used as generating of the high voltage pulsed electric field (PEF). Based on the experiment testing that the high voltage source can produce 80 kV with the efficiency of high voltage DC source is 81.70% and the operating voltage of sphere-gap is 18.5 kV. Therefore, the intensity of the pulsed electric field of the design can be reached at 80 kV/cm. Based on this ranges that design can be used for electroporation process. Furthermore, this tool was tested into a sample, Nematode. For Nematode sample testing, the electric fields strength is E = 37.33 kV/cm on the voltage of between the electrode is 6.7 kV. Thus, the design of the pulsed electric field source using a sphere-gap has functioned.

ELECTROMAGNETIC FIELD INFLUENCES ON HUMAN HEALTH

The environment we live in is exposed to the increasing and increasing frequency of electromagnetic radiation in our homes and workplaces. In addition to natural radiation from the sun, radiation sources such as high-voltage transmission lines and powerful radar devices are sources of strong electric and magnetic fields. Increasing the number of portable communication and entertainment devices also increase the human body's exposure to additional electromagnetic radiation. This paper describes the most common effects of low-frequency non-ionizing electromagnetic fields (ELFs), which can cause biological changes, sometimes negative for human health. Different methods and approaches are used to investigate the effect of non-ionizing electromagnetic fields on biological systems. In vitro cell culture studies provide important insights into the underlying mechanisms of biological effects of low radiation levels. It is often not possible to deduce the functional response of a human organism to a particular biological effect. In vivo animal and human studies provide more convincing evidence of possible adverse health effects. There is a problem with the extrapolation of the results obtained from animal experiments to humans. Epidemiological studies provide the most direct information on the risk of adverse effects in humans. However, it is difficult to find good control groups that in all aspects (gender, similar life habits, etc.) fit the exposed groups. Care should be taken in interpreting the results of epidemiological studies, especially if low risk is found, as this may be due to other factors. Epidemiological studies are important for monitoring the impact of new technologies on human health [1].

Simulation of electric fields generated from microtubule vibrations.

Microtubules are tubular proteins that form part of the cytoskeleton in eukaryotic cells. Because of their unique mechanical properties, many studies have theorized microtubules could show high-frequency mechanical vibrations. Others have further suggested these vibrations of the electrically polar microtubules could be a source of electric fields inside the cell that could serve some biological function, such as a role in organizing mitosis or also possibly in cell-to-cell communication. In this work, we use a transient method to simulate the electric fields that would be generated from a single microtubule supposing they could sustain vibrations. We evaluate the biological significance of the electric fields and the potential energy microtubules might exert on one another. Our simulation method allows us to evaluate vibrational modes that have not previously been studied. The simulations suggest the acoustic branch flexing mode would actually be the most electrically active. Our results suggest a single vibrating microtubule could potentially exert significant forces (those that exceed thermal energy) on biological dipoles or charges at distances larger then the Debye length, on the order of 10nm from the surface of the microtubule, but interaction is not likely at greater distances.

Numerical simulation and experiment of error field measurement using luminous trace of electron beam in SST-1

In contrast to the earlier experiments conducted in other machines, here, in SST-1 the error field measurement experiment is performed with a filled gas pressure ∼8 × 10−4 mbar which helped to create a luminescent toroidal beam of electron path originated due to impact excitation and guided by the toroidal magnetic field. Beam path deviations are observed and recorded from radial and top ports using visible range cameras. Such creation and detection of the electron beam path differs from the earlier works where the gun emitted electron beam deviation in ultra-high vacuum was detected on a collector-grid/fluorescent screen. In the present experiment, large beam deviations were observed. Later investigation of the experimental set-up reveals existence of a possible source of radial electric field in between the source and the vacuum vessel which are separately grounded. Thus, to understand the observed phenomena, experiments are numerically modeled with deviated TF coil set, PF coil set and the electron source location. A particle tracing code is used to follow the electron path in the magnetic field generated by the coil set of interest. Simulation results suggest that the large deviation corresponds to the E × B drifts and not due to the large field errors. Toroidally averaged field errors of the SST-1 TF coils at toroidal field of B0 = 15 kG are negligibly small ∼B0 × 10−6 or less, which should not adversely affect the plasma performance.

Improvement in the Silicon Solar Cell Performance by Integration of the Electric Field Source in the Solar Cell Under Sunlight Illumination

This manuscript presents a theoretical modeling of conversion efficiency improvement in a typical polycrystalline Si solar cell in 1D assumptions under multispectral sunlight illumination. The improvement is brought by the increase in the collection of the minority carriers charge in excess. This increase is the consequence of the integration of the electric field provided by the use of the open-circuit photovoltage of another silicon solar cell. We assume that two silicon solar cells are integrated to the system. The first solar cell provides the open-circuit photovoltage which is connected to two aluminum planar armatures creating a planar capacitor. The second solar cell is placed under the uniform electric field created between the two aluminum armatures. This study has shown that the photocurrent generated is improved by the conduction current given by this electric field. It shows that an improvement in the electric power, particularly its maximum value, leads to the improvement in the conversion efficiency and the fill factor. We observe an improvement in the second silicon solar cell performances for the shortest distance between both aluminum conductors.

Global Ionospheric Current System Associated With Penetration Electric Field and New Mechanism for the Generation of Dayside Westward Electric Field at Low Latitudes During Northward IMF

AbstractIt is well known that penetration and shielding electric fields are related to the southward and northward turnings of the interplanetary magnetic field (IMF). The shielding electric field is assumed to be caused by the region‐2 field‐aligned currents. We have analyzed observations of equatorial ionospheric plasma drifts measured by the Jicamarca incoherent scatter radar and global ground magnetic perturbations in an event when the IMF fluctuates between southward and northward. The vertical plasma drifts/zonal electric fields in the dayside equatorial ionosphere are well correlated with the IMF reorientations, indicating that the disturbance electric fields in the equatorial ionosphere are caused by the IMF. Magnetometer data are used to reconstruct the global ionospheric currents and convection. The DP 2 current system consists of a large vortex in the afternoon‐evening sector and a much smaller vortex in the dawn sector, and the ionospheric currents associated with the dayside penetration electric field extend into the postmidnight sector. The downward plasma drift and southward magnetic perturbations at equatorial latitudes during northward IMF are correlated with the reverse convection in the polar cap, indicating that the polar electric field associated with the reverse convection is an important source of the westward electric field in the dayside equatorial region. A new mechanism is proposed to explain the generation of westward electric field in the dayside equatorial ionosphere during northward IMF.

Numerical analysis of SAR and temperature distribution in two dimensional human head model based on FDTD parameters and the polarization of electromagnetic wave

In the modern environment, electromagnetic waves from various types of transmission antennas, such as those in cell phones are propagating around the human body. The electromagnetic (EM) wave is absorbed by the human body and some undesirable effects occur in the tissues. The specific absorption rate (SAR) is a useful parameter for measuring these effects. In this study, changes in human body temperature, considered as thermal effects, are computed in a tissue-based analysis of the SAR. The finite difference time domain (FDTD) method and the bio-heat equation are used primarily to calculate the consequent effects. Two-dimensional formulation of FDTD is applied in the computing, and the propagation of the electric field is investigated in two polarizations: transverse electric (TE) wave, and transverse magnetic (TM) wave. The electric field source is kept near the human head which is designed as structured layers.

Damage from Coexistence of Ferroelectric and Antiferroelectric Domains and Clustering of O Vacancies in PZT: An Elastic and Raman Study.

It is often suggested that oxygen vacancies (V) are involved in fatigue and pinning of domain walls in ferroelectric (FE) materials, but generally without definite evidence or models. Here the progress of damage induced by the coexistence of FE and antiferroelectric (AFE) domains in the absence of electric cycling is probed by monitoring the Young’s modulus, which may undergo more than fourfold softenings without significant changes in the Raman spectra, but may end with the disaggregation of PZT with ∼5% Ti. At these compositions, the FE and AFE phases coexist at room temperature, as also observed with micro-Raman, and hence the observations are interpreted in terms of the aggregation of V at the interfaces between FE and AFE domains, which are sources of internal electric and stress fields. The V would coalesce into planar defects whose extension grows with time but can be dissolved by annealing above 600 K, which indeed restores the original stiffness. The observed giant softening is interpreted by assimilating the planar aggregations of V to flat inclusions with much reduced elastic moduli, due to the missing Zr/Ti−O bonds. A relationship between the coalescence of a fixed concentration of V into planar defects and softening is then obtained from the existing literature on the effective elastic moduli of materials with inclusions of various shapes.

Effects of secondary electron emission on plasma characteristics in dual-frequency atmospheric pressure helium discharge by fluid modeling**Project supported by the National Natural Science Foundation of China (Grant No. 11505089).

A one-dimensional (1D) fluid simulation of dual frequency discharge in helium gas at atmospheric pressure is carried out to investigate the role of the secondary electron emission on the surfaces of the electrodes. In the simulation, electrons, ions of He+ and , metastable atoms of He* and metastable molecules of are included. It is found that the secondary electron emission coefficient significantly influences plasma density and electric field as well as electron heating mechanisms and ionization rate. The particle densities increase with increasing SEE coefficient from 0 to 0.3 as well as the sheathʼs electric field and electron source. Moreover, the SEE coefficient also influences the electron heating mechanism and electron power dissipation in the plasma and both of them increase with increasing SEE coefficient within the range from 0 to 0.3 as a result of increasing of electron density.

Relationship Between Basic Physiochemical Properties of Seawater and Magnitude of Underwater Electric Field

Abstract Passive defense systems which minimize chance of vessel detection have to be utilized due to application of naval mines. Passive defense and signature minimization can be regarded as not only magnitude reduction but also as its shaping. Electric field magnitude at a given depth is a function of an electric field source but also it depends on physicochemical properties of seawater — temperature and salinity. In this paper results of underwater electric field simulations are presented. Cases of various depths, temperatures and salinities are shown. Computational results are compared to underwater electric field measurements performed with portable sensor.

Computation and analysis of the extremely low frequency electric and magnetic fields generated by two designs of 400 kV overhead transmission lines

The overhead transmission lines are considered one of the major sources of electric and magnetic fields, which can induce electrical currents within the human body. In this study, the electric and magnetic fields generated by two recent designs of 400 kV transmission lines used in the Romanian power system are computed and compared to the exposure limits established by the International Commission on Non-Ionizing Radiation Protection for the general public. The computations are carried out with two dedicated software tools, called PowerMag and PowerELT, which have been developed based on a 2D quasi-static analytical approach. This approach, as well as the electric and magnetic field distributions obtained for the considered 400 kV overhead transmission lines, will be discussed in detail. To confirm the validity of the results, some comparisons to finite element computations will also be presented.

In-plane electric field controlled ferromagnetism and anisotropic magnetoresistance in an LSMO/PMN-PT heterostructure

We report the in-plane electric field controlled ferromagnetism of La2/3Sr1/3MnO3 (LSMO) films epitaxially deposited on [Pb(Mg1/3Nb2/3)O3]0.7-(PbTiO3)0.3 (PMN-PT) (001), (011) and (111) single crystal substrates. The in-plane coercivities (Hc∥) and remanences of the LSMO films greatly depend on the in-plane electric field applied on the PMN-PT (001) and (011) substrates. The experimental change of Hc∥ is consistent with the Stoner–Wohlfarth model and first principle calculation with the electric field varying from −10 to 10 kV cm−1. Moreover, the Curie temperature and anisotropic magnetoresistance of the LSMO films can also be manipulated by an in-plane electric field. Finally, the LSMO/PMN-PT (001) heterostructure is designed to be a new kind of magnetic signal generator with the source of electric field.

Computation of electric field inside substations with boundary element methods and adaptive cross approximation

Power system substations and HV power lines are sources of electric and magnetic fields of industrial frequency. Guidelines for permissible electric and magnetic field strengths regarding human exposure and electromagnetic compatibility (EMC) are provided by standards. In this paper a novel method for calculating 3D electric field near power system facilities is presented. Computation procedure is based on integral equations and boundary element methods. The influence of polynomial order of functions used to approximate the unknown linear charge densities over the elements is tested for constant, linear and cubic spline functions. Due to a complex geometry of substations, a large system of equations needs to be solved to find the unknown charge densities over the elements of the model. In order to reduce computational efforts adaptive cross approximation (ACA) is employed. The results of computation are in a good agreement with measurements.

Plasma globe revisited

The plasma globe or plasma ball is an underutilized resource for teaching the physics of electricity. It also offers a convenient source of electric field that can be used for demonstrations and experiments. Unlike the Van de Graaff generator, the plasma globe does not shock you and is essentially silent. Other authors have written up some of these activities, but the full potential of the plasma globe is generally not taken advantage of by most teachers. I hope that this article can bring more awareness to how this ubiquitous piece of novelty lighting can be an essential physics teaching apparatus.

Improvement of the Silicon Solar Cell Performance by Integration of an Electric Field Source in the Solar Cell or Solar Module System

This manuscript is about a theoretical modelling of conversion efficiency improvement of a typical polycrystalline Si solar cell in 1D assumptions. The improvement is brought by the increase of the collection of the minority carriers charge in excess. This increase is the consequence of the influence of an electric field provided by the use of the open circuit photovoltage of another silicon solar cell. We assume that it is integrated two silicon solar cells to the system. The first solar cell provides the open circuit photovoltage which is connected to two aluminum planar armatures creating a planar capacitor. The second solar cell is placed under the uniform electric field created between the two aluminum armatures. This work has shown an improvement of the output electric power leading to the increase of the conversion efficiency. We observe an increase of 0.7% of the conversion efficiency of the second silicon solar cell.