High-intensity Electric Fields Research Articles

An avalanche transistor-based Marx circuit pulse generator with sub-nanosecond, high frequency and high-voltage for pathogenic Escherichia coli ablation

Pathogenic Escherichia coli, which will easily cause environmental pollution, is a potentially hazardous microorganism that enters the environment through various routes such as biological feces. The presence of this bacterium poses a serious health risk, especially in water sources. When consuming water containing excessive amounts of pathogenic Escherichia coli, both humans and animals may experience severe health issues, such as diarrhea and gastrointestinal infections. However, current treatment methods for this bacterium are not ideal, and traditional means sometimes struggle to completely eliminate these stubborn microorganisms. In recent years, the scientific community has been exploring new sterilization techniques to address this challenge without causing secondary environmental pollution. Among them, pulsed electric field (PEF) technology has garnered significant attention. By applying high-intensity electric field pulses, PEF technology can have a fatal impact on microbial cells in a very short period of time. Studies have shown that this technology can cause cell membrane perforation, destroying the integrity of the cell and leading to cell death. This method is not only capable of decomposing organic pollutants, but also has a significant bactericidal effect. Nevertheless, despite the theoretical potential of PEF technology, there is still relatively little research on its application, especially in terms of treating pathogenic Escherichia coli. Further studies and experimental verification are needed. This article investigates the bioelectromagnetic effects of electric pulses on pathogenic Escherichia coli in sewage through a self-developed pulse source device (capable of providing a voltage range from 1.7 kV to 2.2 kV, with a rise time of 190 ps and a maximum repetition rate of 20 kHz). The feasibility of using a pulsed electric field to purify water bodies is verified in this report.

Pulsed Electric Fields Effects on Proteins: Extraction, Structural Modification, and Enhancing Enzymatic Activity.

Pulsed electric field (PEF) is an innovative physical method for food processing characterized by low energy consumption and short processing time. This technology represents a sustainable procedure to extend food shelf-life, enhance mass transfer, or modify food structure. The main mechanism of action of PEF for food processing is the increment of the permeability of the cell membranes by electroporation. However, it has also been shown that PEF may modify the technological and functional properties of proteins. Generating a high-intensity electric field necessitates the flow of an electric current that may have side effects such as electrochemical reactions and temperature increments due to the Joule effect that may affect food components such as proteins. This article presents a critical review of the knowledge on the extraction of proteins assisted by PEF and the impact of these treatments on protein composition, structure, and functionality. The required research for understanding what happens to a protein when it is under the action of a high-intensity electric field and to know if the mechanism of action of PEF on proteins is different from thermal or electrochemical effects is underlying.

Dielectric relaxation spectroscopy of hybrid insulating nanofluids in time, distribution, and frequency domain

Improving the dielectric properties of insulating liquids belongs to the modern motivation to optimize the operation of high-voltage devices. Hybrid nanofluids can provide the mentioned improvement, and thus, it is necessary to reveal their hidden potential. This study investigates hybrid nanofluids with different concentrations of magnetite and fullerene nanoparticles, a separate fullerene and magnetic nanofluid, and a base carrier fluid based on gas-to-liquid technology. The investigated samples are subjected to dielectric relaxation spectroscopy analysis at three applied electric field intensities in the time, distribution, and frequency domain. The lack of information about the studied parameters of the mentioned nanofluids is another reason for our experimental measurements. A significant dispersion of the charging current characteristics of nanofluids with magnetic nanoparticles is observed. At lower electric field intensities, the increasing fullerene concentration of the hybrid nanofluids reduces the charging currents up to a charging time of 200 s. Magnetic nanofluid shows the highest values of conductivity currents. Experiments show that the suspension of fullerene in the base oil causes a higher charging current and a more pronounced relaxation response than pure base oil. Significant relaxation information in the low-frequency band is detected from the distribution spectra. At higher electric field intensities in the low-frequency spectrum, the relaxation peaks decrease when the concentration of fullerene in hybrid nanofluids increases. The distribution area shows the effect of higher polarizability of magnetite nanoparticles. Compared to lower electric field intensities, at the value of 333.3 kV/m, several polarization processes are captured in the entire frequency spectrum. The frequency-dependent complex permittivity confirms the findings from the time and distribution domains. Comparing the distribution domain with the frequency domain shows higher sensitivity and accuracy in capturing relaxation processes in the distribution domain.

Interference voltage measurement and analysis of cardiac implants exposed to electric fields at extremely low frequency

Objective. The possibility of interference by electromagnetic fields in the workplaces with cardiac implants is a concern for both individuals and employers. This article presents an analysis of the interference to which cardiac implants are subjected under high-intensity electric field at the power frequency. Approach. Evaluations of interference were conducted by studying the induced voltages at the device input in the real case study and the substitute study, and establishing an association between them with the equivalence factor F. A funnel-shaped phantom, designed for in vitro testing and representing the electrical characteristics of the locations where cardiac implants are installed, was used in the substitute study. A measuring system was implemented to measure the induced voltage at the device input under high intensity electric fields. Main results. The induced voltages obtained in the experimental measurements align with the findings of the numerical study in the phantom. By applying the equivalence factors derived between the real case study and the substitute study (2.39 for unipolar sensing; 3.64 for bipolar sensing), the induced voltages on the cardiac implants can be determined for the real case using the substitute experimental set-up. Significance. The interference voltages on the cardiac implants under electric field exposures at low frequency were experimentally measured with detailed description. The findings provide evidence for an analysis method to systematically study the electromagnetic interference on the cardiac implants at low frequency.

New insights of selective rupture of synthetic sample under high voltage pulse discharge: A numerical simulation of electric field distribution

Herein, COMSOL Multiphysics is proposed to discuss the electric field distribution of synthetic sample during the high voltage pulse discharge crushing. The pulses number required for high voltage pulse discharge to crush the synthetic sample filled with magnetite is lower than that required for quartz-filled samples. The embedding mode that the magnetite is located on the central line between the high voltage electrode and the grounding electrode of the synthetic sample is most conducive to electrical breakdown of synthetic sample. The discharge channel developed along the magnetite edge and retains the complete crystal form of magnetite. Differences in dielectric constants are responsible for variations in electric field distribution. Magnetite alters the distribution state of electric field within synthetic samples to derive higher electric field intensity and more extensive areas with high electric field intensity. The peak electric field intensity at the interface of magnetite particles is higher than that of quartz. The presence of quartz particles hinders the development of certain discharge channels.

Evaluation of electrokinetic-assisted phytoremediation efficiency of dibutyl phthalate contaminated soil by maize (Zea mays L.) under different electric field intensities

The excessive accumulation of dibutyl phthalate (DBP) in soil poses a serious threat to soil ecosystems and crop safety production. Electrokinetic-assisted phytoremediation (EKPR) has been considered as a potential technology for remediating organic contaminated soils. In order to investigate the effect of different electric fields on removal efficiency of DBP, three kinds of electric fields were set up in this study (1 V·cm−1, 2 V·cm−1 and 3 V·cm−1). The results showed that 59 % of DBP in soil was removed by maize (Zea mays L.) within 20 d in low-intensity electric field (1 V·cm−1), and the accumulation of DBP in maize tissues decreased significantly compared to the non-electrified treatment group. Interestingly, it could be observed that the low-intensity electric field could maintain ion homeostasis and improve the photosynthetic efficiency of the plant, thereby relieving the inhibition of DBP on plant growth and increasing the chlorophyll content (94.1 %) of maize. However, the removal efficiency of DBP by maize decreased significantly under the medium-intensity (2 V·cm−1) and high-intensity electric field (3 V·cm−1). Moreover, the important roles of soil enzyme and rhizosphere bacterial community in low-electric field were also investigated and discussed. This study provided a new perspective for exploring the mechanism of removing DBP through EKPR.

Mechanistic insight into the Janus Green B on electrochemical roughening layer of copper foil

This study explores the impact of the electroplating additive JGB the surface characteristics and peel strength of electrolytic copper foils used in printed circuit boards. Utilizing Scanning Electron Microscopy and Atomic Force Microscopy, we found that optimal JGB concentrations enhance the morphology and roughness of the copper foil roughening layer while maintaining high peel strength. The ideal concentration of 3 mg/L achieved an average roughness of 0.953 µm and a peel strength of 0.946 N/mm. JGB's effectiveness in inhibiting copper deposition was confirmed through cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy. Density Functional Theory calculations and in situ infrared spectroscopy elucidated JGB's adsorption and coordination actions, which have a synergistic effect on its inhibitory performance. Further investigations with molecular dynamics simulations and finite element analysis demonstrated JGB's preferential adsorption in areas of high electric field intensity, effectively controlling the copper grain morphology in the roughening layer. This research highlights the potential of dye-type additives in improving copper foil roughening for printed circuit boards applications. Future research should explore the long-term stability and environmental impact of JGB in industrial applications, while investigating other dye-type additives may further optimize the roughening process to meet diverse printed circuit boards manufacturing needs.

Phase-field fracture modelling of piezoelectric quasicrystals

In this paper, an electro-elastic phase field model is developed for brittle fracture in piezoelectric quasicrystals. The elastic field of quasicrystals is composite of a phonon field and a phason field. The phonon field, phason field and electric field are coupled with each other, and the phonon and electric loadings trigger the variation of both the phonon and phason elastic energies, which then together contribute to crack evolution. The cracks initiation and propagation in piezoelectric quasicrystals under quasi-static mechanical loading and electric loading can be well predicted. Several numerical examples are performed to evaluate the effects of electric field and anisotropic fracture toughness. Simulation results show that the electric field influences the initial force, peak force, fracture displacement and crack path. For the single-edge notched tensile test, the effects of electric field force on the initial force, peak force and fracture displacement are obvious. For the single-edge notched shear test, the electric field force has no effect on the initial force, but it affects the peak force, fracture displacement and crack path. For the porous plate tensile test, a high-intensity electric field can deflect crack substantially resulting in passing through different holes. Further simulation indicates that the anisotropic fracture toughness has a significant effect on peak force, fracture displacement, and crack path. The present model can be used to simulate various fracture problems of piezoelectric quasicrystals.

Experimental investigation of a modified triboelectric charging device

Tribo-charging of plastic particles plays a critical role in the electrostatic separation industry, particularly for sorting millimeter-sized particles. The optimal charge/mass ratio can result in significant particle deviation in high intensity electric fields, making tribo-charging an important area of study. This work examines a modified tribo-electrostatic charging device that utilizes rotating propellers and an added air blower to increase particle charging. Through experimental analysis, the impact of air blower speed, rotating propeller speed, and sample mass was investigated using five different types of millimeter-sized particles. The results of the optimization study indicate a significant improvement in the charge/mass ratio, with the introduction of the air blower increasing the ratio by over 2.5 times.

The Impact of Pulsed Electric Field Technology on Enzymes, Microbial and Nutritional Quality in Milk Processing - A Comprehensive Review

A pulsed electric field is a non-thermal technology used in the processing of foods, especially liquid foods such as milk, fruit juices, etc. The objective of this review is to provide an understanding of pulsed electric field technology and its application in milk processing, particularly in whole milk, skim milk, and UHT milk. This technology can be used as an alternative to traditional heat treatments such as pasteurizing, hot filling, blanching, and sterilization. In this technology, short high-intensity electric field is used at moderate temperatures. A pulsed electric field is an effective technology to inactivate microorganisms and enzymes with minimum changes in nutritional, functional, and organoleptic qualities compared to heat treatments. Pathogenic and spoilage bacteria can be reduced effectively when using pulsed electric field technology. However, there are variations between studies. As a recent advance, the pulsed electric field is used with mild heating. This shows a significant reduction in microbial count with less detrimental effects on the physico-chemical and organoleptic properties of food. It also has minimal impact on nutrients present in the milk such as proteins, milk fat globules, and vitamins. In this review, we describe in detail the introduction, the principle of pulsed electric field, the impact of pulsed electric field on microorganisms, enzymes, and nutrients, and the advantages and disadvantages of using PEF technology. Further studies can be conducted to investigate the combined approach of the pulsed electric field with mild heating treatment methods including pasteurization and sterilization.

Influence of alternating electric field on electrorheological effect of aqueous dispersions of stevensite

Upon deionization of the aqueous dispersion of stevensite, a type of smectite clay minerals, a low-viscosity colorless transparent dispersion is obtained. The phenomenon known as the electrorheological (ER) effect has been previously reported when a weak electric field of several V/mm is applied to the stevensite aqueous dispersion. In this study, the influence of the waveform and frequency of the electric field was investigated while keeping the electric field intensity constant. It was observed that as the acceleration of the applied electric field intensity increased, the stress response to the electric field improved. Increasing the frequency of the electric field led to a reduction in the induced stress; however, it improved the response rate of stress. It has been indicated that even at higher electric field frequencies, the potential for observing the ER effect exists with higher electric field intensities. Maintaining a low electrolyte concentration may facilitate the development of novel ER fluids capable of instantaneously responding to the application or removal of electric fields.

Comparative analysis of installations for heat treatment of non-food pulp raw materials by the influence of electrophysical factors

Relevance. The objectives of the work are to develop radio-hermetic installations and substantiate the effective design of the working chamber, which provides a comprehensive effect of electrophysical factors on non-food pulp raw materials to preserve feed value at reduced operating costs. Scientific tasks: 1) to develop installations with different designs of resonators; 2) to conduct a comparative analysis of the working chambers according to the main parameters; 3) to evaluate the technical and economic indicators of an effective installation in relation to the basic version.Methods. The effect of electrophysical factors on raw materials is realized in resonators with magnetrons and frequency generators of pulse-modeled high-frequency oscillations of 110 kHz, where a bactericidal flux lamp serves as a high-potential electrode.Results. Several continuous-flow radiohermetic installations with ultrahigh-frequency (microwave) power supply to non-standard resonators have been developed, inside which a complex effect of a high-intensity electric field, a bactericidal flow of UV rays and ozone is realized to reduce bacterial contamination of the product and neutralize odor during heat treatment of raw materials, the dimensions of which are consistent with the depth of penetration of the wave. Features of conical and biconic resonators − provide radio leakage in continuous operation by cutting off the tip at the level of the critical section, depending on the angle of inclination of the cone generator, and allow you to keep the standing wave inside the resonator. The combination of magnetron and cylindrical resonators increases the efficiency of the interaction of the electron flux with the microwave field, and an increase in the inductive volume, which is a “reservoir” of energy, increases the intrinsic quality of the resonator. A quasi-toroidal resonator, presented as a conical resonator in a toroidal resonator, having small overall dimensions and metal consumption, provides a traveling wave in the annular space, and a standing wave in the conical space. The high electric field strength in the capacitor part of the resonator and the corona discharge in the torus contribute to the disinfection of raw materials.

Blue-white electroluminescence of diamond/WS2 quantum dot composite films

Two kinds of diamond films with completely different morphologies were prepared on N-type heavily doped silicon wafers by microwave plasma chemical vapor deposition (MPCVD) method, namely, micron-scale large grain polycrystalline diamond film dominated by (220) crystal plane (220DF) and nano-scale small grain polycrystalline diamond film dominated by (111) crystal plane (111DF). And WS2 quantum dot powder was obtained by aqueous liquid phase ultrasonic method. Then, the 111DF/WS2 quantum dot composite structure film (111DWSF) and 220DF/WS2 quantum dot composite structure film (220DWSF) were prepared by applying WS2 quantum dot powder uniformly on diamond film substrate. The results of electroluminescence (EL) detection show that the 220DWSF device emits visible blue light, and the main peak of EL spectrum is located at 443 nm in the blue region. The 111DWSF device emits white light, and the corresponding EL spectra show strong emission peaks in the blue region (454 nm), green region (536 nm) and red region (632 nm) respectively, meanwhile, the luminous intensity of 111DWSF device is much higher than that of 220DWSF device. In addition, it is also found that the 220DWSF EL device does not show obvious rectification characteristics, while the 111DWSF EL device has obvious rectification characteristics. After FN fitting of the IV characteristic curve of 111DWSF EL device, the tunneling characteristics of electrons are found in the region of high electric field intensity.

Deep ultraviolet AlGaN-multiple quantum wells with photoluminescence enhanced by topological corner state

The AlGaN-based deep ultraviolet light-emitting diode (DUV LED) has advantages of environmentally friendly materials, tunable emission wavelength, and easy miniaturization. However, an increase in Al composition leads to a decline in the lattice quality, thereby reducing the internal quantum efficiency (IQE). In addition, the light extraction efficiency (LEE) is limited due to the strong transverse magnetization polarization emission from the multiple quantum wells. Here, we designed the topological corner structure in AlGaN-MQWs, and the high electric field intensity in a tiny space at the corner results in an extremely high local density of optical states (LDOS), which could shorten the luminescence decay time of the emitter and increase the radiative rate by 26 times. Meanwhile, because the excited topological corner state resonance mode is a transverse-electric mode, enhancing only the transverse-electric luminescence without any gain for transverse-magnetic luminescence, thereby significantly improving the light extraction efficiency. Finally, according to theoretical calculations, the IQE could reach 68.75% at room temperature.

Striated composite layers of silica and hafnia offering advantageous properties for short-pulse optical coatings.

Monolayers containing subnanometer striations of silica and hafnia to form composite materials at varying ratios are explored as a method to develop high-index dielectric layers with increased laser-induced-damage thresholds (LIDTs). These layers can then be used in multilayer dielectric coatings for short-pulse, high-peak-power laser applications, particularly in regions of the highest electric-field intensity. Fabrication is achieved by means of exposure to two different evaporant vapor plumes, where local exposure to each plume is controlled via shielding to prevent simultaneous exposure. The LIDT of the resulting layers has been evaluated at 1053 nm with 600-fs pulses. The results indicate that such hafnia/silica layers exhibit LIDTs similar to silica for a refractive index of ≤1.65. These results suggest that the use of these layers in locations subjected to high electric-field intensity within multilayer dielectric coatings may significantly improve the LIDT, with this deposition process providing particular benefit for scaling to large-aperture, high-fluence components.

Microwave sintering of Ti(C,N)-based cermets: Study of the magnetic effect on metal phase

For microwave heating of Ti(C,N)-based cermets, this paper presents a microwave heating simulation study of pure Ti(C,N) ceramics and Ti(C,N)-based cermets using Comsol software. S-parameter inversion is employed to determine the equivalent relative permittivity of Ti(C,N)-based cermets with varying metal contents. The pairwise Ni metal plate model is utilized to investigate the law of mutual coupling voltage between metal plates. It was found that vigorous electric field intensity is generated around the metal particles of Ti(C,N)-based cermets, and high electric field intensity is generated between the metal particles. Model slice analysis and mechanism analysis are combined to reveal the following phenomena: (1)The surface of metal particles in Ti(C,N)-based cermets excites induced electromagnetic fields; (2)High mutual coupling voltages are generated between metal particles; (3)The reflection effect of metal particles on microwaves can increase the electric field intensity between metal particles. By statistically analyzing the temperature data of pure Ti(C,N) ceramics and Ti(C,N)-based cermets during the initial 30-min microwave sintering period, the temperature difference changing law can be concluded: (1)During the initial 30 min of microwave sintering, the temperature difference between the two gradually increased with time; (2)At 30 min, the temperature difference between the two reached 111 °C.

Continuous Production of High-Concentration Nitrated Water with Catalytic Concentrated High-Intensity Electric Field Process at Ambient Conditions

Continuous Production of High-Concentration Nitrated Water with Catalytic Concentrated High-Intensity Electric Field Process at Ambient Conditions

Structural design and simulation study of intelligent defect elimination equipment for high‐voltage transmission line pin defects

AbstractTransmission lines may suffer from pin defects, necessitating regular patrols and maintenance. The traditional maintenance approach not only involves a substantial workload and low efficiency but also poses a threat to the safety of maintenance personnel. To address the issue of pin defects in high‐voltage transmission lines, this paper introduces the design of an intelligent pin‐eliminating robot. The research focuses on two main aspects: firstly, analyzing the transmission line environment and employing Solidworks software to design the mechanical structure of the robot. Subsequently, a static stress analysis of the robot's structure is conducted to ensure the rationality of the design. The second aspect addresses the impact of the robot on the electric field distribution of the transmission line in high electric field intensity areas and whether the robot itself experiences discharge phenomena. COMSOL simulation software is utilized to globally calculate and analyze the electric field of the robot. Research results indicate that the threshold for the curvature radius of the pin‐eliminating robot's tip is 2.5mm, and values below this threshold may lead to the occurrence of discharge phenomena. The optimized pin‐eliminating robot, under normal operation, does not exhibit discharge phenomena in a 500kV strong electric field.

Role of dielectric force and solid extraction in electrohydrodynamic flow assisted melting

A numerical study of non-isothermal solid-liquid phase change process in a differentially heated square cavity aided with an electrohydrodynamic (EHD) flow is reported. Melting of a phase change material (PCM) subjected to an electric field with different charge injection strengths is studied. The study aims to numerically demonstrate the solid extraction phenomenon and its role in accelerating the melting process. The EHD flow modifies the flow structure and notably alters the solid–liquid interface morphology. The dielectric force extracts the semi-solid PCM from the melt interface into the liquid bulk with high electric field intensity. The dielectric force causes melting-rate enhancement during the initial stages of melting. While, the later stages of melting are influenced by the combined action of Coulomb and dielectric forces. The role of the Coulomb force is weaker in the weaker charge-injection regimes. Higher electric potential and stronger charge injection generally lead to increased melting rates. Up to 62.12 % decrease in total time taken for melting is achieved within the parameters considered herein.

Unipolar carrier multiplication high-gain and low-noise AlGaN ultraviolet avalanche photodiode with periodically stacked structure

Highly sensitive avalanche photodetector (APD) has become a promising candidate for detecting extremely weak target signals. However, the impact ionization multiplication simultaneously triggered by electrons and holes will lead to large excess noise, thus significantly influencing device avalanche performance. Herein, we propose a distinctive AlGaN-based ultraviolet avalanche photodiode with AlN/Al0.2Ga0.8N periodically stacked multiplication region. The higher effective masses and density of states in valence band renders holes limited in the quantum-well region, where thermalization plays a dominant role during carrier transport process. On the contrary, in the atomic-scale AlN/AlGaN stacked structure with a periodic thickness of 10 nm, the electron mutualization motion is conductive to electron obtaining sufficient energy to induce impact ionization. Hence, the mechanism of unipolar carrier induced avalanche multiplication effectively reduces device noise and improving multiplication gain. Meanwhile, the high electric field intensity and tilted energy band in the AlGaN/AlN periodically stacked region significantly contribute to the carrier impact ionization. Consequently, the device achieves a superior avalanche gain of more than 105 at 74 V reverse bias. It is envisioned that the unipolar carrier triggering avalanche events offers a viable route to build high-performance APDs.