Effect Of Electric Field Intensity Research Articles

Sodium dodecyl sulfate assisted electric field treatment for deproteinization of chitosan

Chitosan with a low protein residue is required as it is widely used in the field of biomedicine. Herein, we proposed a novel method for deproteinizing industrial grade chitosan via electric field treatment in a medium containing sodium dodecyl sulfate (SDS). The effects of electric field intensity, SDS concentration, and electrophoresis time on the protein removal efficiency were optimized by orthogonal experimental design and model building. Chitosan with an ultra-low protein residue (0.151 wt%) can be obtained at the voltage of 300 V, the SDS concentration of 1 wt%, and the electrophoresis time of 2 h. The strong binding between SDS and residue protein renders the conjugate with negative charges, which can migrate under the electric field. In addition, the electric field deproteinization process reduces the heavy metal content of chitosan slightly, while keeping the chemical structure of chitosan unchanged. The methodology provided in this work suggests the great potential of electric field treatment in removing residue protein in chitosan.

Study on Bridging Characteristics of Fiber Particles in Flowing Insulating Oil Under DC Electric Field

This paper investigates the bridging behavior of fiber particles in insulating oil under the background of flow-electric coupled field, which is of great significance for explaining the micro-discharge and the deterioration of overall electrical property of insulating oil in transformer. Based on the observation experiments, a constructed oil circulation device and shooting system is used to study the bridging characteristics of fiber particle swarm in oil flow under DC electric field. The effects of electric field intensity, oil flow velocity and mass fraction of particles in oil on the bridging process are analyzed in detail, and the changes of conduction current between electrodes under different conditions are recorded. The results show that the bridging behavior of fiber particle swarm is the result of the combined action of flow field and electric field. The forces provided by electric field on the fiber particles cause them to aggregate and bridge between electrodes, and with the increase of field intensity, the bridging speed increases significantly. The influence of flow velocity is more complicated, and it has different effects on the bridging process of particles under low and high field intensity. The mass fraction of fiber particles in oil is negatively correlated with the difficulty of bridging between electrodes. Finally, the bridging mechanism is explained from the perspective of the forces on particles and electric field distortion, and the variation characteristics of conduction current between electrodes are analyzed.

Antireflective coatings of chitin nanofibers on glass fabricated through electric field deposition

Due to their wide variety of practical applications, antireflective coatings have been studied intensively. In this paper, we developed a novel approach to fabricate antireflective coatings on glass substrate by using charged chitin nanofibers (ChNFs) and electric field deposition. The ChNFs were obtained via ultrasonic treatment of the modified chitin through partial deacetylation, esterification and esterification followed partial deacetylation (dual modification), respectively. The ChNF coatings prepared by applying electric field deposition and using aqueous dispersions of the dual modified ChNFs had antireflective capacity. The effects of electric field intensity, electric field application time and ChNF dispersion concentration on antireflective capacity of the ChNF coatings were studied. The coating obtained by applying 55 V electric field for 5 min and using the dispersion of the dual modified ChNFs with concentration of 0.05 wt% yielded increase in transmittance of a glass substrate (∼ 2.4% at wavelength of 550 nm). The results of this study demonstrate that electric field deposition is a high efficiency and low cost approach to prepare antireflective coatings on large size and nonplanar substrates with charged nanofibers.

Effect of electric field intensity on droplet fragmentation in oil-in-water-in-oil (O/W/O) emulsions: A molecular dynamics study

Oil-in-water-in-oil (O/W/O) emulsions commonly exist in crude oil treatment, food processing, pharmaceuticals, and cosmetics; however, few related studies have been conducted. To reveal the fragmentation mechanism of droplets in O/W/O emulsions, the behavior of complex droplets under different electric field intensities was investigated using a molecular dynamics method. It was found that the deformation of the intermediate phase (water) and the internal phase (hexane) increased dramatically with the electric field intensity, and the two phases separated when E ≥ 1.1 V∙nm−1, indicating that the complex droplets had been simplified into two simple liquids. Observation of the droplet trajectory shows that the deformation of the internal phase was smaller than that of the intermediate phase, and the internal oil droplet moved toward the high electric potential position. Furthermore, we elaborated the interactions between different phases at the molecular level by means of weak interactions and radial distribution function analysis, and their magnitudes were as follows: Cl− - Na+ > Na+ - Water > Water - Hexane. The electric fragmentation mechanism of the complex droplets was investigated, which provides theoretical guidance for the treatment of O/W/O emulsions by electrodehydration.

Charging Characteristics of Micrometer-Sized Metal Particles and Their Effects on Partial Discharge of Insulating Oil in Flowing

In this study, the motion behavior of micron-sized metal particle swarm in case of flow-electric field coupling is observed in a non-contact manner based on the experiments. According to the results of observation, the charging characteristics of metal particle swarm in insulating oil flow under DC electric field are analyzed in detail, and the effects of electric field intensity, voltage type and oil flow velocity on the charging process and motion of particle swarm are studied. The obtained results show that the applied electric field will cause the streamlines of velocity of the metal particles to oscillate along its direction, where such effect becomes more obvious as the electric field intensity increases. The increase of oil flow velocity can weaken the influence of electric field and make the streamlines of velocity tend to be flat. The oscillation effect of streamlines of velocity under AC electric field is much weaker than that of DC electric field. In addition, based on the measured kinetic parameters of particles, it is found that the charge quantity of the moving particles in the gap of electrodes has the characteristics of temporal and spatial variations, and the particles have a variety of charging modes, including collisional charging, charge transfer, neutralization and accumulation. High velocity of flow and the alternating electric field hinder the charge transfer between particles, resulting in a decrease in the overall charge of the particle swarm. Finally, from the perspective of micro-discharge and electric field distortion, we explain the influence mechanism of flow velocity and voltage type on the discharge characteristics of oil flow containing metal impurities.

Effect of electric field intensity on chloride binding capacity of concrete

Determining the binding capacity of concrete to chloride ions has always been the focus of the durability study of reinforced concrete structures. In many cases, concrete interior is in the electric field environment, such as railway track affected by stray current, component under electrical chloride removal (ECR), and concrete in corrosion electric field. However, the influence of electric field intensity on the chloride binding ability of concrete has not been determined clearly and quantitatively. In this paper, an experimental study is conducted to investigate the evolution of chloride binding capacity under various electrical current densities. The results indicate that the binding capacity of concrete is degraded by the electrical field, and the amount of physical adsorption for chloride is far less than the that of chemical binding. Based on experimental data, the modified Langmuir isotherm is given, and the evolution of key coefficients is measured quantitatively. The research findings are of great significance to the accurate evaluation of subsequent transmission of chloride ions after the initiation of steel corrosion and corrosion protection effect by ECR technique.

Preparation of Gd2Zr2O7 nanoceramics by flash sintering and two-step flash sintering

Preparation of Gd2Zr2O7 nanoceramics using a simple and low energy-consuming approach is significant for their wide range of applications. In this work, flash sintering (FS) and two-step flash sintering (TSFS) were first utilized to prepare Gd2Zr2O7 nanoceramics. The effects of electric field intensity and current limit on the densification and grain growth were investigated. The grain size was decreased with the increase of electric field intensity. Meanwhile, both grain size and density were increased with the increase of current limit. The Gd2Zr2O7 nanoceramics with an average grain size of 98 nm and a relative density of 92.8% were prepared by FS. By contrast, the Gd2Zr2O7 nanoceramics with the higher relative densities of 96.3–97.5% and the smaller average grain sizes of 85–90 nm were prepared by TSFS. Compared to FS, TSFS can achieve suppressed grain growth and fast densification. The as-prepared Gd2Zr2O7 nanoceramics showed excellent hardness and fracture toughness. The sample breakage caused by current localization can be avoided by controlling the current ramp after the occurrence of the flash event.

Effect of electric field intensity on electrophoretic migration and deformation of oil droplets in O/W emulsion under DC electric field: A molecular dynamics study

Removing oil droplets from O/W emulsion is a difficult problem at present. In order to explore the effect of electric field intensity on the migration and deformation of oil droplets in O/W emulsion, in this paper, the motion behavior of oil droplets under DC electric field is studied based on molecular dynamics simulation. It is found that oil phase molecules are attracted together by Van der Waals interaction. When E = 0.7 V/nm, the deformation degree reaches the maximum 0.534, and the overall migration speed of the oil droplet is 0.03266 nm/ps. Negative electrophoretic migration of oil droplets occurs under electric field, which is similar to the experimental results. The effect of electric field intensity on oil droplet migration and deformation is explored for the first time, and the relevant results can provide theoretical guidance for improving the purification process of oily wastewater.

Effect of electric field intensity on domain kinetics of Pb(Mg1/3Nb2/3)O3–0.38PbTiO3 single crystal

As one of the outstanding piezoelectric materials, relaxor-PbTiO3 single crystal also exhibits promising electro-optic and nonlinear-optic properties. Therefore, it is vital to understand the domain switching kinetics not only for optimizing strain-mediated devices performance but also for fabricating optical waveguides and periodic domain structures in optical applications. In this work, domain switching kinetics in annealed and pre-poled PMN-0.38PT single crystal under different external electric field were studied. Polarization reversal can be accomplished only by c-domain nucleation and growth in the annealed sample where the formation of the ferroelastic domains is hindered. In pre-poled sample, 90° domain switching happened by 90° domain wall reorientation under low electric field while 180° domain switching is accomplished by two-step 90° domain switching and c-domain growth under high electric field. The results are important for modulating domain structure for strain mediated and optical devices.

Oscillating evaporation of pendant droplets under the action of ionic wind

Evaporation of charged droplets is the fundamental aspect of many technologies, such as the electrospray cooling, spray drying, and ink-jet printing. In this study, the ionic wind flow properties, as well as the subsequent oscillating characteristics and evaporation performance of the hanging droplets influenced by the ionic wind were experimentally investigated. Deionized water was used as the working fluid and digital camera was used to capture the evaporation behavior of pendant droplets. Particle image velocimetry (PIV) was employed to characterize the ionic wind flow generated by a pin-to-plate non-uniform electric field, where the needle electrode was connected to a high-voltage power supply. Effects of electric field and gas environment on the evaporation rate, oscillation amplitude and oscillation frequency were systematically studied. The results showed that the ionic wind will not appear until the applied voltage is higher than the corona voltage (6 kV for air). The critical corona voltage varied with the ambient gas. Without ionic wind, the evaporation was found restrained by the electric body force. On the opposite, the evaporation process was enormously improved when the ionic wind was formed. In addition, the development state of ionic wind would change from unstable form to fusiform shape when the voltage raised. Both the increase in external electric field strength and the ion mobility in gas were found to increase the ionic wind speed which leaded to the enhancement of oscillation amplitude and evaporation rate. Effect of electric field intensity on droplet evaporation could stack with ion mobility with a maximum enhancement ratio of about 9.9 times compared with naturally evaporated droplets. This study demonstrated that the ionic wind significantly enhanced the evaporation of pendant droplets, which would contribute to a better understanding of the heat transfer enhancing mechanism under the non-uniform electric field.

Electromagnetic effects on dynamics of string fluid and information paradox in rainbow gravity

This work is devoted to studying the effects of electric field intensity on collapsing anisotropic string fluid in Rainbow gravity. The Einstein field equations are modified and solved for the spherical symmetric spacetime. The physical parameters of fluid including energy density, pressure and string tension are obtained. Moreover, the time and radius of formation of the apparent horizon are estimated. All these quantities depend on the fluid’s electric intensity. The graphical analysis of the physical existence of dynamical quantities depending on the energy of the probing particle is presented. It is found that the presence of an electric field decreases the mass density and increases fluid’s pressure. The electric field increases the time and radius of apparent horizon formation resulting in slowing down the collapsing process.

Electrospun cellulose fibers from ionic liquid: Practical implications toward robust morphology

AbstractFibrous matrix of cellulose was obtained by wet‐type electrospinning of cellulose in ionic liquid, 1‐butyl‐3‐methylimidazolium acetate (BMIMAc). The experiments were designed to determine the effects of electric field intensity and the amount of dissolved cellulose on cellulose fiber morphology and diameter. Taking to account practical implications, that is, fiber size and the effectiveness of production, the most effective production of fibers took place using 3% cellulose/BMIMAc solution at electric field of 4.8 kV cm−1, feed rate of 2.38 ml h−1. Analysis has shown that cellulose was fully dissolved and consisted purely of regenerated cellulose (type II), while having porosity of 90% and average fiber width of 1.95 ± 0.9 μm. The scanning electron microscopy and micro‐computed tomography analyses revealed a robust structural integrity of the formed fibrous matrix, which featured an area density of 85 ± 8 g/m2. The mechanical properties (strength of 12.03 ± 1.1 MPa; strain at break 2.6 ± 0.3%) indicate that in this study strong fibrous cellulose matrix was formed which could be used for the production of biocomposites or as biocompatible scaffolds.

Microbial community and metabolic responses to electrical field intensity for alleviation of ammonia inhibition in an integrated bioelectrochemical system (BES)

Bioelectrochemical system (BES) is a promising solution for mitigation of ammonia inhibition in anaerobic digestion (AD) process. However, the effect of electric field intensity on microbial community changes and metabolic function prediction during the alleviation of ammonia inhibition are still missing. The results of the current study represented that the improvement of ammonia removal (20.6%) and methane production (14.6%) could both be achieved at 0.2 V while higher voltages led to reductions of methane production (more than 48.9%) compared with the control. Moreover, hydrogenotrophic methanogens (Methanobacterium) seemed to be more robust to high voltages compared with aceticlastic methanogens (Methanosaeta). Additionally, bacteria for hydrolysis and acidogenesis (Rikenellaceae and Soehngenia) were found vulnerable to external electric field intensity. Furthermore, abundances changes of metabolic pathways demonstrated that the degradation of carbohydrates, lipids and proteins during all steps (hydrolysis, acidogenesis, acetogenesis and methanogenesis) of AD process could be affected by different applied voltages.

Numerical simulation of a falling droplet surrounding by air under electric field using VOF method: A CFD study

This is a numerical study of a falling droplet surrounding by air under the electric field modeled with finite volume method by means of CFD. The VOF method has been employed to model the two-phase flow of the present study. Various capillary numbers are investigated to analyze the effects of electric field intensity on the falling droplet deformation. Also, the effects of electric potential on the heat transfer coefficient have been examined. The obtained results showed that by applying the electric field at a capillary number of 0.2 the droplet tends to retain its primitive shape as time goes by, with a subtle deformation to an oblate form. Intensifying the electric field to a capillary number of 0.8 droplet deformation is almost insignificant with time progressing; however, further enhancement in capillary number to 2 causes the droplet to deform as a prolate shape and higher values of this number intensify the prolate form deformation of the droplet and result in pinch-off phenomenon. Ultimately, it is showed that as the electric potential augments the heat transfer coefficient increases in which for electric potential values higher than 2400 V the heat transfer coefficient enhances significantly.

Maximum deformation of charged dielectric droplets

In this study, the maximum deformation of micrometer sized droplet of dielectric water-based paint impact onto a flat steel surface and exposed to a constant and uniform electric field was investigated by simulation based on the level-set method within the framework of Navier-Stokes. Upon a series experiments for droplet impacting and spreading of water-based paint on dielectric solid substrate with different initial impacting velocities in external electric field, results demonstrated that the maximum deformation ratio increases with the increase of initial impacting velocity, and can scale as We1/4 where We is the Weber number. The effect of electric field intensity to the final shape of droplet of water-based paint on a hydrophobic surface was investigated. It was found that the eccentricity of droplet can scale as E where E is the electric field intensity, and a prediction model of droplet between the deformation ratio (ξF) of droplet at final equilibrium contact angle and E was presented. Finally, the effect of applied voltage and equilibrium contact angle was studied.

The research on Surface charge of super-bihydrophobic nano-coating materials

Using high bonding energy, low surface energy of polymer-based insulation materials, blending modification of nanoparticles, the composite material surface and internal building “micro-nano” super hydrophobic structure, realization of polymer-based the preparation of nano super hydrophobic insulation materials, to make it break the super hydrophobic material only on the surface to construct “micro-” hydrophobic structure, improve its wearability and applicability, realize “existence is effective” super hydrophobic properties. The surface charge characteristic test and internal mechanism of polymer-based nano-composite super-hydrophobic insulating materials were studied. The conductance transformation mechanism of nano-composite super-hydrophobic insulating materials under different temperature and high field intensity curves was used. Combined with the study of surface charge, the effects of electric field intensity, electrode material, temperature, humidity and doped particles on surface charge of nano-composite super-hydrophobic insulating materials are analyzed.

The Effect of Combined AC Electric Field-Ultrasound on Pasteurization and Chemical Compositions of Rose Aromatic water

Essential oil and aromatic water of rose are used in food industry, preparing syrups, giving fragrance to sweets, and widely used in pharmaceuticals and cosmetics in the preparation of a number of medications and ointments. Thermal pasteurization methods cause undesirable changes in taste, smell, medicinal properties and nutritional quality with a reduction in the amount of aromatic water chemical compounds. The objective of the present research was accomplished the pasteurization method with high-intensity Alternative Current electric field and ultrasound waves without heat treatment on rose aromatic water. In this study was examined the effects of power of ultrasound waves (200, 150, 100 W), time of sonication (5, 4, 3 minutes), electric field intensity (5, 7.5 and 10 kV), and time of applying the electric field (5, 20 and 35 seconds) on reduction of E. coli content, energy consumption and chemical compounds of treated rose water. The results showed that the time of applying electric field is more effective in reducing the microbial load compared to electric field intensity, but the effect of electric field intensity on the Energy Per Cycle is more than that of time of applying the electric field. Phenethyl alcohol as the main compounds of rose hydrosol had an acceptable decrease in the combined method as compared with raw rose hydrosol. Furthermore, the proposed method caused to minimal changes in the chemical compositions of the rose water as compared to the conventional heating methods.

Multiple Electrohydrodynamic Effects on the Morphology and Running Behavior of Tiny Liquid Metal Motors.

Minimized motors can harvest different types of energy and transfer them into kinetic power to carry out complex operations, such as targeted drug delivery, health care, sensing and so on. In recent years, the liquid metal motor is emerging as a very promising tiny machine. This work is dedicated to investigate the motion characteristics of self-powered liquid metal droplet machines under external electric field, after engulfing a small amount of aluminum. Two new non-dimensional parameters, named and , are put forward for the first time to evaluate the ratio of the forces resulting from the electric field to the fluidic viscous force and the ratio of the friction force to the fluidic viscous force. Forces exerted on liquid metal droplets, the viscosity between the droplet and the surrounding fluid, the pressure difference on both ends, the friction between the bottom of the droplet and the sink base, and bubble propulsion force are evaluated and estimated regarding whether they are impetus or resistance. Effects of electric field intensity, droplet size, solution concentration and surface roughness etc. on the morphology and running behavior of such tiny liquid metal motors are clarified in detail. This work sheds light on the moving mechanism of the liquid metal droplet in aqueous solutions, preparing for more precise and complicated control of liquid metal soft machines.

Effect of electric field intensity on the performance of positively charged quaternized chitosan nanofiltration membranes

Effect of electric field intensity on the performance of positively charged quaternized chitosan nanofiltration membranes

Effects of Ohmic Heating, Including Electric Field Intensity and Frequency, on Thermal Inactivation of Bacillus subtilis Spores

Methods for microbial inactivation are important in the food industry; however, conventional external heating (CH) reduces food quality. Accordingly, the nonthermal effects of ohmic heating (OH) on Bacillus subtilis spores in a sodium chloride aqueous solution at 101°C (i.e., the boiling point), as well as the effects of electric field intensity and frequency during OH, were investigated. Survival kinetics were compared between OH and external CH. The inactivation effect on B. subtilis was greater for all electric field conditions (5, 10, and 20 V/cm) than for CH. In particular, 20 V/cm showed a significantly higher inactivation effect (P < 0.05) on B. subtilis than those of CH at 8, 10, 12, 14, and 16 min. The survival data were fitted to various primary kinetic models. In the Weibull model and the log-linear model, there were significant differences (P < 0.05) in the rate parameters δ and kmax between OH at 20 V/cm and CH. However, there were no significant differences (P > 0.05) in survival kinetics between 20, 40, and 60 kHz; B. subtilis spores were inactivated more efficiently as the frequency increased. B. subtilis spores were almost completely inactivated at 14 to 16 min for the 60-kHz treatment, but spores were still alive at 20 and 40 kHz for the same treatment times. These results demonstrated that OH inactivates B. subtilis spores more effectively than CH. OH conditions with high electric field intensities and high frequencies resulted in efficient B. subtilis spore inactivation.