Values Of Electric Field Strength Research Articles

К ОБЪЯСНЕНИЮ ЭФФЕКТА ПОВЕДЕНИЯ Г-ОБРАЗНОЙ РАМКИ В ПРИЗЕМНОМ ЭЛЕКТРИЧЕСКОМ ПОЛЕ

The possibility of determining the zones of the reverse electrode effect in hard-to-reach places using an L-shaped frame is considered. It is shown that joint measurements using instruments and an L-shaped frame with adjustable sensitivity will make it possible to convert the recorded angles of frame movement into physically understandable values of the atmospheric electric field strength.

Mapping of electromagnetic fields of industrial frequency in case of urban area

Repeated detailed mapping of values of electric field strength and magnetic induction on 2 streets in the historic center of St. Petersburg is executed. Measurements were carried out according to the existing methodical requirements and taking into account time of peak loadings of the power supply network. The individual binding of points of measurements naturally increases detail of the final map. Excesses of hygienic standards are not revealed, but the values of magnetic induction exceeding approximate safe levels according to results of foreign researches are widespread. The influence of concrete local sources of electromagnetic fields, such as signs, objects of ventilation, lighting, electrical wiring found reflection is presented by maps. The non-standard sources of electromagnetic fields in the form of large metal designs fixed to facades of buildings and subject to electrization are revealed. Growth of values of electric field strength and magnetic induction from the warm period to cold is noted.

Influence of an External Electric Field and Dissipative Tunneling on Recombination Radiation in Quantum Dots.

The effect of an external electric field and dissipative tunneling on the spectral intensity of recombination radiation in a quantum dot with an A+ + e impurity complex (a hole localized on a neutral acceptor interacting with an electron localized in the ground state of the quantum dot) is studied in the zero-radius potential model in the adiabatic approximation. The probability of dissipative tunneling of a hole is calculated in the one-instanton approximation. A high sensitivity of the recombination radiation intensity to the strength of the external electric field and to such parameters of the surrounding matrix (dissipative tunneling parameters) as temperature, the constant of interaction with the contact medium (or the heat-bath), and the frequency of phonon modes, has been revealed. It is shown that an external electric field leads to a shift of the recombination radiation threshold by several tens of meV, and a change in the parameters of dissipative tunneling has a noticeable effect on the spectral intensity of recombination radiation. It is shown that the resonant tunneling effect manifests itself in the form of “dips” in the field dependence of the spectral intensity of recombination radiation, which occur at certain values of the external electric field strength and temperature. This opens up certain prospects for the use of the considered system “quantum dot—impurity complex A+ + e” under conditions of dissipative tunneling for the study and diagnostics of biological objects.

Change of thermophysical parameters of polypropylene-metal oxide nanocomposite (polypropylene + ZrO2) after electric field influence

In this work, the influence of an electric field on thermophysical properties of the PP+ZrO2 nanocomposites has been investigated. Changes in thermograms before and after applying an electric field (EFI) have been studied depending on the filler percentage in the polymer matrix. After EFI a new, weak maximum at the temperature range of 100–130°С of the thermograms for all concentrations of the filler was observed. Thermophysical parameters of the nanocomposite sample have been calculated for different values of electric field strengths that were applied are calculated depending on the effect of the ETP.

Effective Medium Model Applied to Biopolymer Solutions.

Studying dielectric properties of heterogeneous systems is challenged by a problem of uncertainty of the ratio between dielectric permittivity of the system and dielectric permittivities of its components. Such ratios can be obtained in some cases using theoretical effective medium models. However, such models have not yet been developed for all the systems possible. Particularly, there is no effective medium model with filamentary inclusions. Such a theoretical model elaborated based on the fundamental principles of electrodynamics of continuous media is suggested in the present work. Any point of a filamentary inclusion with a length that is significantly greater than the thickness can be regarded as being located in a long cylinder-like fragment of the inclusion with stochastic direction of the cylinder axis relative to the external electric field. With this regard, electric field strength and electric induction values were averaged across the entire volume of a two-phase dielectric material. As a result, a model linking the dielectric permittivity of the two-phase system and the dielectric permittivities of both phases was elaborated. The model appears to be highly relevant for studying solutions of biopolymers, such as nucleic acids, fibrillar proteins and protein aggregates, polysaccharides, by means of electrical impedance spectroscopy, dielectric spectroscopy, and terahertz time-domain spectroscopy. The suggested theoretical model was successfully validated on a DNA solution within the terahertz region.

Экспериментальные исследования электромагнитных полей на электрическом подвижном составе

Objective: To identify the influence of electromagnetic interference of various origins on the func- tioning of electronic components of control systems in electric rolling stock (ERS) and radio commu- nication devices, and the effect of electromagnetic fields (EMF) on humans. To carry out experi- mental studies of the ERS EMF characteristics taken as source data, allowing to assess the need to take appropriate actions to ensure electromagnetic safety. One of such measures is the optimal ar- rangement of electric equipment in the driver’s cabin of an electric locomotive or electric train, which will make it possible to achieve the minimum electric and magnetic field strength values under specified conditions. Methods: Direct measurement of the electromagnetic field characteristics in the driver’s cabin of a new 2ES-5 (2ЭС-5) AC electric locomotive (joint production of Transmashhol- ding JSC, Russia, and Alstom, France), as well as on a 2ES4K (2ЭС4К) DC electric locomotive (driver’s cabin, high-voltage chamber, electric locomotive roof) and an ED4M (ЭД4М) DC electric train (dri- ver’s cabin, train car). In the driver’s cabin, measurements were carried out near the working appa- ratus, near the driver’s and assistant's seats and at frequencies for which the maximum permissible levels have been set. Results: The magnetic field strengths (as having the greatest effect on the func- tioning of the electronic components of the ERS control systems and on the person) in the driver’s cabin of electric locomotives and electric trains were measured at different currents under the fol- lowing conditions: starting, traction, braking in the high-voltage chamber and on the electric locomo- tive roof. Practical importance: The given electromagnetic field characteristics do not exceed the specifications set forth in the regulatory documents of the Russian Federation. However, when trains move, there are bursts of EMF strength values due to transient processes in the power supply sys- tem: on DC ERS, the magnetic field strength in the driver’s cabin reached 100 A/m, the electric field strength — 8,5 kV/m, magnetic induction on the DC electric locomotive roof — 400 μT. These values exceed the maximum permissible levels and require the relevant actions to ensure electromagnetic safety.

Meta-malzeme Yapılı Ayrık Halka Rezonatörün Performans İyileştirmesi için MOGA Algoritması Kullanılarak Üç Boyutlu Elektromanyetik Analizi ve Optimizasyonu

The study presents 3D electromagnetic analysis and optimization of metamaterial constructed split ring resonator. The analysis was carried out under electromagnetic analysis conditions by using electromagnetic boundary conditions master and slave. The operating frequency range, in other words the performance characteristic, has been analysed from 1 GHz to 20 GHz. The split-ring resonator design has been analysed on triple co-axes in accordance with its actual use. Surface current density, electric field strength and magnetic field strength values were examined in the analysis. Metamaterial based split-ring resonators are used in many fields. Today, it has many applications as measurement and sensor or as antenna in 5G applications. In order to obtain a suitable design at high frequencies, micron-level designs are required. Newly developed objective functions are presented in the study. In this study, good results were obtained with an optimized SRR design by using multi-objective genetic algorithm in the range up to 20 GHz that can achieve negative refractive index capacity. These results are presented in the study with the relationship between permittivity and permeability. Furthermore, when the results obtained from the design are examined, it is seen that it is suitable for wireless applications. Performance improvement have been carried out SRR negative refractive index capacity which before has 11 GHz was increased to 15.5 GHz.

Estimation of plasma parameters in a pre-breakdown ionization wave at the glow discharge ignition in argon

The results of an experimental study of a pre-breakdown (slow) ionization wave (IW) in argon-filled discharge tubes of 15 mm i.d. and 80 and 100 cm length at a pressure of 1 and 4 Torr are presented. The breakdown and the IW were initiated by a positive voltage pulse with an amplitude of 2 and 4 kV. The IW was detected by the light emitted from its front. The IW emission spectrum consisted of the argon atomic and ion lines. The Ar(763.5 nm) and Ar+(488.0 nm) lines were used to retrieve the electric field strength value in the IW front. For this, the intensity ratio of these lines was measured. The upper levels for these lines are excited by electron impact, and, due to a large difference between their excitation energies, this ratio strongly depends on the reduced electric field strength E/N (E is the electric field strength, N is the atom number density). Theoretical modeling makes it possible to find a relation between the line intensity ratio and the E/N value. In the model, the axial profile of the IW electric field is approximated by a rectangle with a width determined from the measured emission intensity waveform and the wave velocity. As a result, the E/N magnitude in the IW front was found for various positions along the tube. Emission intensity of the DC discharge was also measured, which allowed us to estimate the emitting level population and electron number density in the IW front. The density of seed electrons ahead of the wave is also evaluated and processes responsible for the appearance of these electrons are discussed.

Experimental Study on the Performance of a Novel Compact Electrostatic Coalescer with Helical Electrodes

As most of the light and easy oil fields have been produced or are nearing their end-life, the emulsion stability is enhanced and water cut is increasing in produced fluid which have brought challenges to oil–water separation in onshore and offshore production trains. The conventional solution to these challenges includes a combination of higher chemical dosages, larger vessels and more separation stages, which often demands increased energy consumption, higher operating costs and larger space for the production facility. It is not always feasible to address the issues by conventional means, especially for the separation process on offshore platforms. Electrostatic coalescence is an effective method to achieve demulsification and accelerate the oil–water separation process. In this paper, a novel compact electrostatic coalescer with helical electrodes was developed and its performance on treatment of water-in-oil emulsions was investigated by experiments. Focused beam reflectance measurement (FBRM) was used to make real-time online measurements of water droplet sizes in the emulsion. The average water droplet diameters and number of droplets within a certain size range are set as indicators for evaluating the effect of coalescence. We investigated the effect of electric field strength, frequency, water content and fluid velocity on the performance of coalescence. The experimental results showed that increasing the electric field strength could obviously contribute to the growth of small water droplets and coalescence. The extreme value of electric field strength achieved in the high-frequency electric field was much higher than that in the power-frequency (50 Hz) electric field, which can better promote the growth of water droplets. The initial average diameters of water droplets increase with higher water content. The rate of increment in the electric field was also increased. Its performance was compared with that of the plate electrodes to further verify the advantages of enhancing electrostatic coalescence and demulsification with helical electrodes. The research results can provide guidance for the optimization and performance improvement of a compact electrocoalescer.

Effect of external magnetic field on lane formation in driven pair-ion plasmas

Lane formation dynamics in externally driven pair-ion plasma (PIP) particles is studied in the presence of external magnetic field using Langevin dynamics (LD) simulation. The phase diagram obtained distinguishing the no-lane and lane states is systematically determined from a study of various Coulomb coupling parameter values. A peculiar lane formation-disintegration parameter space is identified; lane formation area extended to a wide range of Coulomb coupling parameter values is observed before disappearing to a mixed phase. The different phases are identified by calculating the order parameter. This and the critical parameters are calculated directly from LD simulation. The critical electric field strength value above which the lanes are formed distinctly is obtained, and it is observed that in the presence of the external magnetic field, the PIP system requires a higher value of the electric field strength to enter into the lane formation state than that in the absence of the magnetic field. We further find out the critical value of electric field frequency beyond which the system exhibits a transition back to the disordered state and this critical frequency is found as an increasing function of the electric field strength in the presence of an external magnetic field. The movement of the lanes is also observed in a direction perpendicular to that of the applied electric and magnetic field directions, which reveals the existence of the electric field drift in the system under study. We also use an oblique force field as the external driving force, both in the presence and absence of the external magnetic field. The application of this oblique force changes the orientation of the lane structures for different applied oblique angle values.

Path planning of UHV live working hanging basket method based on grid-ant colony algorithm

The live working paths for equipotential operators in the hanging basket method is determined by minimum safety values of various clearances stipulated in regulations. However, the optimization of the safety path planning by the complex gaps is scarce. In this paper, an optimization method for path planning is proposed based on ant colony algorithm. Grid model is established to partition the operation area into different calculation districts, in which key parameters are grid data and obstacle grids. Grid data are the maximum value of the electric field strength on the body surface, calculated by the finite element model. And obstacle grids are grids that dissatisfy the requirements of complex gaps and their data are larger than the air breakdown field strength. Then ant colony algorithm is employed to search for the best operation path with the minimum working distance and the minimum electric field strength value. After that, an application case is illustrated to demonstrate the optimizing processes. At last, the shock U50 test and power frequency corona discharge test are implemented to verify the safety of the optimized path. Therefore, the path obtained by the proposed method scientifically and effectively shortens the distance of the hanging basket method.

ASSESSING THE RISK ASSOCIATED WITH SIMULTANEOUS EXPOSURE TO MOBILE COMMUNICATION SIGNALS WITHIN 900–2500 MHZ IN NIGERIA

In this study, the total exposure due to signals within GSM 900, GSM 1800, CDMA-1900 and 3G-2100 frequency bands at 200 m from the foot of 120, 100 and 80 base station masts in the Nigerian cities of Lagos, Ibadan and Abuja, respectively, was assessed. A calibrated hand-held spectrum analyser was used to measure the level of power (in dBm) of each signal within the mobile frequency bands. The exposure quotient associated with the combine electric field strengths from the various frequency bands in each city was estimated. The maximum value of total electric field strength at each point in Lagos, Ibadan and Abuja was 0.83V/m, 0.53V/m and 1.63V/m, respectively. This study shows that the exposure quotient due to the simultaneous exposure to the four bands of mobile communication signals in each city is far less than one, as recommend by International Commission on Non-Ionizing Radiation Protection.

Simulation of electron transfer processes in a semiconductor structure using graphene and boron nitride

This paper presents the results of simulating the electron transfer processes in a three-dimensional semiconductor structure containing graphene and layers of boron hexagonal nitride using the Monte – Carlo method. Graphene is currently considered one of the most promising materials for the creation of new semiconductor devices with good performance for high frequency ranges. The use of graphene, which has high mobility of charge carriers, high thermal conductivity and a number of other positive properties, allows the development of new semiconductor devices with good output characteristics. The simulation allowed us to obtain the main characteristics of electron transfer, namely, dependence of speed, average energy, mobility on the strength of the electric field in a semiconductor structure containing a layer of graphene and boron nitride region. Electron transfer processes were simulated considering temperature variations of graphene and boron nitride layers, which is observed with increasing strength of the electric field in the structure. The analysis of the obtained dependencies showed that at small values of electric field strength, which does not exceed approximately 2.5 kV/cm, there is a nonlinear change in electron energy and temperature. At more significant values of electric field strength a quasi-linear change in temperature is observed. The similar course of dependence is observed also for the dependences of the average energy of electrons on the intensity of the electric field for the graphene layer.. The resulting dependencies of electron transfer characteristics can serve the basis for determining output characteristics in multi-layer semiconductor devices containing layers of graphene, boron hexagonal nitride and other materials.

Optimal Design of Large Signal Performance of AlN/GaN Hetero-Structural IMPATT and MITATT Diodes

Hetero-structure of AlxGa1-xN/GaN exhibits important applications in high frequency and large power devices. In this paper, AlN/GaN is adopted to optimal design the large power impact avalanche transit time (IMPATT) and mixed tunneling avalanche transit time (MITATT) diodes operating at the atmospheric low loss window frequency of 0.85 THz. The static state and large signal characteristics of the devices are numerically simulated. The values of peak electric field strength, break-down voltage, avalanche voltage, the maximum generation rates of avalanche and tunneling, admittance-frequency relation, output power, conversion efficiency, quality factor of the proposed hetero-structural IMPATT and MITATT diodes are calculated, respectively. Via comparing the obtained results of (n)AlN/(p)GaN and (n)GaN/(p)AlN IMPATT diodes to those of the MITATT counterparts, there exists little performance difference between IMPATT and MITATT devices while implies significant difference between the (n)AlN/(p)GaN and (n)GaN/(p)AlN diodes.

Performances of Velvet Cathodes With Different Geometries in a Reflex Triode Vircator

A frequency tunable vircator, which has the reflex triode geometry, was designed and experimentally tested. The cloth velvet was used as the cathode material. The planar and the Ernst-profiled velvet cathodes, which have diameters of 40, 50, 60, and 70 mm, were used in the experiments. The electric field strength values and the corresponding frequencies of the radiated microwave were measured and analyzed for each of the cathodes. The anode–cathode distances between 4 and 16 mm were swept in the experiments. The planar cathodes display larger electric field strength values, whereas the Ernst-profiled cathodes have wider frequency ranges. The characteristics of the velvet, such as tuft density and fiber dimensions, were investigated in detail using scanning electron microscope images. The condition of the vacuum was also observed during shots.

Dental Amalgam Influence on the Amount of Absorbed Energy from Mobile Phone

The topic of the research presented in this paper is numerical calculation and analysis of the electric field and Specific Absorption Rate (SAR) distributions in the vicinity of dental amalgam exposed to the radiation of mobile phone at the frequencies corresponding to 3G and 4G mobile networks. This is carried out by numerical solving of the electromagnetic propagation equation. The results related to different tissues and organs placed in the vicinity of dental amalgam and exposed to radiation are presented and analysed. In order to obtain the most accurate results, the realistic 3D model of human jaw has been created. A comparative analysis of models with and without dental amalgam has been carried out, with aim to determine the impact of amalgam on biological tissues in its vicinity. According to the obtained results, the maximum values of electric field strength and SAR are higher in the presence of dental amalgam. In both cases, maximum values are out of bounds of safety limits.

Measurements of shear stress in ER/MR fluids used in valves by adapting centrifugal force

The article introduces a new flow rheometer of a simple structure, designed to determine the blocking stress in valves with electrorheological (ER) and magnetorheological (MR) fluids. It combines the advantages of rotary and flow rheometers. In this rheometer, a flow of a small ER/MR fluid sample placed in a revolving channel, is forced by the centrifugal force. The designed rheometer has a characteristically simple structure due to the lack of components such as pistons or pumps used to induce the flow of ER/MR fluid, and it does not have the basic disadvantage of flow rheometers, which is the necessity to analyse a large sample of fluid. The results of measurements conducted with the new rheometer were compared with results from two standard rheometers: a flow rheometer and a rotary rheometer. In order to adjust the measurement results from the new rheometer to these obtained from standard rheometers, the research featured a method of selecting numerical coefficients occurring in formulas used to calculate shear stress. The method is based on optimization method and it minimizes the differences between measurements for the same values of electric or magnetic field strength.

Water distillation using an ohmic heating apparatus

Many regions, including Basrah Governate in Iraq, suffer from undrinkable water due to high salt content and an economical means of desalinisation is needed. Ohmic heating was tested as a potentially more efficient method for water distillation compared to traditional resistance heating. An ohmic heating distillation apparatus was designed, manufactured, and tested to remove Ca and other metals from high salt content tap water. Ohmic heating was used as a lower operational cost alternative to a traditional distillation device. Three values of electric field strength (7, 9, and 11 V/cm) were used. The results showed that the highest water distillation productivity was 500 ml/hr using both electrode configurations at 11 V/cm, while the lowest yield of the device was at 7 V/cm with the vertical electrodes. The results showed a significant decrease (p < 0.05) in the electrical conductivity and TDS values for all electric field strengths compared to untreated tap water. The lowest values were 0.85 μS/cm and 0.45 ppm, respectively, with both horizontal and vertical electrodes, while the highest values were 1.65 μS/cm and 1.2 ppm, respectively, using the electric field strength of 7 V/cm with the horizontal electrodes.

Effect of moderate DC electric field on formation of surfactant-laden drops

The continuous formation of mm-scale surfactant-laden aqueous drops in oil was studied under an applied DC electric field of 0–267 kV/m. The parameters varied included the flow rate of dispersed phase, the electric field strength, the viscosities and densities of dispersed and continuous phase and the surfactant type (anionic or cationic) and concentration. An increase in the electric field strength resulted in a decrease of the drop size due to increasing stresses on the drop interface. The size reduction continued until transition to the irregular regime. The values of critical electric field strength for this transition increased with an increase in both the flow rate and the viscosity ratio between the dispersed and continuous phase. The critical electric field strength and the size of the drops formed in the periodic dripping regime were independent of the electric field polarity. The effect of the electric field increased with a decrease of interfacial tension and density difference between the dispersed and continuous phase.

Shape and electric performance improvement of an insulator string using particles swarm algorithm

In this study, a particle swarm optimisation (PSO) algorithm coupled with finite-element method (FEM) is implemented to improve the performance of a cap-and-pin insulator by reducing the value of maximum electric field strength. Two goals are set in this work: (i) optimisation of the tangential electric field distribution and magnitude (which is taken as the objectif function to be minimised) to reduce the risk of flashover due to surface pollution, and (ii) reduction of the creepage distance (by adopting adequate constraints) leading to a reduction of the surface area and consequently a decrease in the insulator weight. The investigation is divided into two parts; first, one-unit insulator is optimised with which a chain is constructed, and its performance compared with the reference insulator string. The second part considers a whole chain of four-unit insulator whose performance is optimised and compared to that of a reference insulator string. The main finding of this work indicates that, if an insulator string is constructed using an optimised cap-and-pin unit, the performance of the so-formed string is also optimised. The optimisation of a complete string leads to practically the same performance as that of a string obtained by assembling optimised insulator units.