Application Of Electric Field Research Articles

Tunable terahertz piezoelectric-based one-dimensional photonic crystal

One-dimensional ternary photonic crystals with dielectric and piezoelectric layers offer intriguing properties and potential applications in the terahertz (THz) region. In the first plan, a piezoelectric layer is placed between two different dielectric layers, resulting in a structure with a controllable band gap through the application of an external electric field. In the second plan, a ternary photonic crystal is proposed, consisting of dielectric layers and a piezoelectric defect layer. This structure introduces a narrow bandpass region that can be finely adjusted using both the external electric field and the incident angle. The bandpass region is characterized by a Gaussian shape, centered around a frequency of approximately 50 THz, with a full width at half maximum (FWHM) of around 50 GHz. The proposed photonic crystal exhibits versatile tunability as a narrow bandpass filter in the THz range. The utilization of an external electric field facilitates the development of optical crystal applications, making it easier to manipulate and control the properties of the photonic crystal.

Comparison of Different Circuit Topology for Generation of PWM Signal with High Power for Electroporation

Electroporation refers to a microbiological method which involves application of electric field to cells for ameliorating the cell membranes permeability, allowing electrode arrays, drugs and chemicals to be inserted into the cells. This process requires HV pulses or signals for creating pores within the cell membrane. As these signals are less effective, nowadays, Pulse Width Modulation (PWM) signals are extensively employed for electroporation. These signals can be exploited for constructing coveted output voltage in power amplifiers and are found to be useful for regulating power devices. Therefore, generation of top quality PWM signals is essential for achieving superior electroporation performance. Different PWM methods are available and circuit topologies employed for generating these waveforms are also different. This paper thus provides an exploratory study of distinct circuit topologies exploited for generating PWM waveforms. The review paper also provides the significance of PWM signals for electroporation. It reviews the existing circuit topologies exploited for PWM signal generation and other related studies. It also presents a circuit for PWM waveform generation. The paper then provides the substantial future directions pertaining to the study. This review article mainly educates the reader regarding existing circuit topologies for PWM signal generation, their characteristics and improvements required for developing better topologies satisfying the requisites of modern applications.

Electrohydrodynamic convection instabilities observed in suspensions of cellulose nanocrystals

Cellulose nanocrystals are slender, negatively charged nanoparticles that spontaneously form a cholesteric liquid crystal in aqueous suspension above a critical concentration. When they are suspended in apolar solvents such as toluene using surfactants, the application of an AC electric field leads to the reorientation and then distortion of the cholesteric order until the cholesteric structure completely unwinds into a nematic-like order, typically above 0.4–0.6 kV/cm at 1kHz. In this work, we show that at much higher electric fields (ge 4.6 kV/cm at 1 kHz) the sample develops a periodic pattern that varies with the field amplitude. We ascribed this pattern to electrohydrodynamic convection instabilities. These instabilities usually present complex regimes varying with the field, the voltage, the frequency and the geometry. However, the typical geometry where these instabilities were most documented across the literature differs from the geometry used in this work. This work concludes with possible future experimental investigations to clarify the exact regime of instability responsible for these observations.

Mechanosynthesis, Structure and Photoluminescent Properties of the Pr3+ Doped LiNbO3, LiNbO3:Mg, LiTaO3 Nanopowders

In the current work, nanocrystalline powders with different compositions, namely Li0.98Pr0.02NbO3, Li0.93Pr0.02Mg0.05NbO3 and Li0.98Pr0.02TaO3 were synthesized for the first time using the method of high-energy ball milling of the starting materials (Li2CO3, Nb2O5, Ta2O5, MgO, Pr6O11), followed by high-temperature annealing. XRD data analysis confirmed the absence of parasitic phases in the obtained nanocrystalline compounds. The estimated particle sizes ranged from 20 to 80 nm. From the obtained nanopowders, ceramic samples were prepared using specially developed equipment, which allowed for pressing at elevated temperatures with a simultaneous application of a constant electric field. The obtained photoluminescence spectra exhibit characteristic features of Pr3+ ions in the crystal structure of LiNbO3 and LiTaO3 and are most efficiently excited by UV light. Samples pressed with an electric field application show higher intensity of photoluminescence. Investigations of the temperature dependence of electrical conductivity of the Li0.98Pr0.02NbO3 sample, pressed with the application of an electric field, indicate that the conductivity mechanism is similar to that of LiNbO3 single crystals and, at high temperatures, is attributed to the lithium conduction mechanism.

Application of electric fields to improve cementation homogeneity of biogrouted sands

AbstractThe inhomogeneity of cementation is a common problem in soil improvement with microbially induced carbonate precipitation process (MICP), which is caused by uneven spatial distribution of bio‐induced calcium carbonate precipitation. Electric field adjustment method was developed and adopted for improving cementation homogeneity of bio‐grouted sands in this research. Horizontal one‐dimensional biogrouting experiments were conducted in sand columns under 0.1 V/cm of direct current (DC) electric field. The column treated with DC electric field showed a significant improvement in homogeneity of calcium carbonate precipitation as compared to the control (without DC electric field). Spatial distribution of calcium carbonate in columns were affected by the properties of bacteria, whether suspended or attached. In general, the attached bacteria with uneven spatial distribution played an important role in the calcium carbonate precipitation when flow rate was regulated at 0.54 cm/min, while the suspended bacteria could also be attached upon times with consumption of cations during biogrouting. With the influence of electric field, suspended bacterial transport in porous media occurred in one direction to the target locations because of the electrophoresis at an average speed of 0.14 cm/h, while sodium ion was found to be moved from anode to cathode by electromigration approach. Electrolysis of water, on the other hand, resulted a slight fluctuation in pH, even though this variation did not show any significant effect on the metabolic activity of bacteria and microbial‐induced carbonate precipitation process. The redistribution of suspended bacteria and sodium ion in porous media provided a possible for attached bacteria to distribute uniformly, which could be considered as the key factor to influence spatial distribution of the bio‐induced calcium carbonate in application of electric field adjustment method.

Pulsed Electric Fields vs. Pectolytic Enzymes in Arinto Vinification: Effects on Yield and Oenological Parameters

The increase in awareness of consumers and producers regarding the sustainable production and consumption of food commodities is motivating the emergence of new technologies to improve the efficiency of pre-established methods and reduce or supplant the usage of production factors. Thus, innovative technologies, such as the nonthermal application of pulsed electric fields (PEFs), may play a crucial role in the optimization of processes, both economically and environmentally (shrinkage of wastage, energy efficiency and decrease in the use of food additives), without compromising the quality of the final product. Thus, a comparison was made between the application of commercial-grade enzymes and PEF treatment to assess the impact on cuvée white grape must and on wine yield and quality. Oenological parameters were evaluated during alcoholic fermentation and after 3 months, with tartaric stability measured after 6 months. For this, assays resorting to 1.5 tons of Arinto grapes were separated into nine similar batches: three control, three treated with enzymes (1.5 g/100 kg) and three subjected to PEFs (1 kV/cm; 2 kJ/kg) at a rate of 4 ton/h. PEFs presented the highest increase in cuvée wine yield of 5.47%; a reduction of 19% of wine lees production was also determined. The effect of PEFs on pH, total acidity, turbidity, total phenols, color intensity, %Ye, total dry extract, volatile acidity and tartaric stability was studied and compared with control and enzymatic treatment. PEF and enzyme usage direct costs were determined; the employment of PEFs represented a direct cost of 0.12 EUR/ton, while enzyme usage was 1.80 EUR/ton.

Rigidity of dipolar coupled H2O molecular network in external electric field

We have performed the first study of the effect of an external electric field on the quantum paraelectric state of the electric dipolar lattice of polar water molecules confined within nano-sized cages of beryl crystal lattice. The complex dielectric permittivity ε* = ε'+iε" of a water subsystem in hydrous beryl is measured at frequencies 1 Hz-1 MHz in the temperature interval 10–300 K both in zero and 7 kV/cm external field. For comparison, we measure dielectric response of conventional quantum paraelectric KTaO3. In KTaO3, the application of electric field of several kV/cm suppresses quantum fluctuations and leads to a shallow maximum of ε′(T) around 15 K that could indicate a diffuse phase transition. In hydrous beryl, however, a bias electric field of up to 7 kV/cm has no effect on the dielectric response of the water molecules network. This result is confirmed by Monte Carlo simulations. We attribute the enhanced rigidity of the water dipolar subsystem to the strong long-range dipole-dipole interaction between separate H2O molecules. The field that could affect the polarization state of the dipoles is estimated to be of the order of 100 kV/cm.

Enhancing heat transfer with 50%–50% water‐ethylene glycol hybrid nanofluid flow over a nonlinear stretching sheet

AbstractIn this article thermophysical properties of nanoparticles with water‐ethylene glycol mixture and its impact in augmenting of heat transport is presented. Boundary layer flow over a stretching surface with simultaneous effects of viscous dissipation, radiation, electric and magnetic field are taken into account. Self‐similarity transformation is utilized to modify the flow governing equations into system of differential equations and solved by shooting method. Program code is validated with existing results in literature and results shows good agreement. Influence of various physical parameters are visualized and Nusselt number, skin friction quantities are computed. We have observed that application of electric field increases Nusselt number. Eckert number decreases the Nusselt number for both nanofluid and hybrid nanofluid.

Enhancement of piezophototronic hydrogen evolution reaction through the polarization of ferroelectric Bi4Ti3O12 microplates

In this study, we analyzed the properties of Bi4Ti3O12 microplates in the context of hydrogen evolution reaction. Piezoresponse force microscopy revealed a typical butterfly curve, indicating that as-synthesized Bi4Ti3O12 exhibits ferroelectric properties. Under ultrasonication, the amount of hydrogen produced by polarized (2000 V) Bi4Ti3O12 increased from 728 to 1349 μmol g−1, which was 1.85 times higher than that generated by unpolarized Bi4Ti3O12. The increase in hydrogen evolution rate may be attributed to the gradual alignment of polarization within the ferroelectric domains of Bi4Ti3O12. Moreover, with synergistic piezophototronic activity, the amount of hydrogen produced by Bi4Ti3O12 was further increased to 1478 μmol g−1, which was 200% higher than that generated by unpolarized Bi4Ti3O12. Theoretical calculations revealed that Bi4Ti3O12 microplates exhibit a high piezoelectric potential along the x-axis, which is consistent with the spontaneous polarization of the microplates. By applying an external polarization field, ferroelectric polarization was activated to effectively separate free charges and extend carrier lifetime (from 0.6 to 0.84 ns). The application of an external electric field to ferroelectric Bi4Ti3O12 appears to be a favorable strategy for enhancing its piezophototronic activity. Our findings may facilitate future studies in the fields of environmental science and renewable energy.

Ionic Gating for Tuning Electronic and Magnetic Properties

The energy-efficient manipulation of the properties of functional materials is of great interest from both a scientific and an applied perspective. The application of electric fields is one of the most widely used methods to induce significant changes in the properties of materials, such as their structural, transport, magnetic, and optical properties. This article presents an overview of recent research on the manipulation of the electronic and magnetic properties of various material systems via electrolyte-based ionic gating. Oxides, magnetic thin-film heterostructures, and van der Waals 2D layers are discussed as exemplary systems. The detailed mechanisms through which ionic gating can induce significant changes in material properties, including their crystal and electronic structure and their electrical, optical, and magnetic properties, are summarized. Current and potential future functional devices enabled by such ionic control mechanisms are also briefly summarized, especially with respect to the emerging field of neuromorphic computing. Finally, a brief outlook and some key challenges are presented.

Control and promotion of probiotic cells' aggregation and viability using DC electric field and standing acoustic waves

Bacterial cells' long-term stability can be induced through cell aggregation. This study aimed to stimulate probiotic cells' aggregation, suspended in 10 mM KH2PO4 at 18 ± 2 °C, utilizing DC electric fields (10–100 mA) and combined electric field (40 mA) with standing acoustic waves (at a frequency range of 26 kHz to 296 kHz). It was demonstrated that the sole application of acoustic waves on the rod-shaped Bifidobacterium animalis subsp. lactis (BIFIDO) did not trigger cell aggregation. However, the application of DC electric field to BIFIDO, induced polarization and aggregation of the BIFIDO cells, as indicated by spectrophotometric measurements (OD600) and visualized by fluorescence microscopy. The aggregation of BIFIDO cells was accelerated (∼6 times) when applying simultaneously DC electric field and standing acoustic waves, due to the accumulation of the cells at the acoustic pressure nodes, and due to the polarization of the cells by dielectrophoresis (DEP) phenomenon. The synergistic effect of DC electric field and standing acoustic waves not only facilitated the aggregation of the cells, but also considerably enhanced the hydrophobicity of BIFIDO cells, without compromising their viability or altering their surface charges. Enhanced viability and stability of the aggregated probiotic cells, in comparison to the non-aggregated, was also observed. Industrial relevanceThe present study points out the application of DC electric field and Standing Acoustic waves to aggregate probiotic cells. An important attribute of aggregated cells is their greater tolerance to environmental stresses. This technology could be applied for large-scale manipulation and aggregation of cells, as for instance during fermentation, prior to drying or encapsulation of cells, or during other industrial cell treatment technologies.

Enhancement of a pyroelectric body energy harvesting scheme employing pulsed electric fields.

This research utilizes waste heat energy as a sustainable energy source to enhance pyroelectric power output by combining pyroelectric nanogenerators with an external pulsed electric field. When the surface temperature of the pyroelectric body varies, applying different pulses of the external electric field results in maximum power accumulation. A novel power-generating experimental setup was developed to measure and compute pyroelectric power generation. A standard Fuji ceramic C-9 sample was used to generate pyroelectric energy in a 20 °C temperature range from 120 to 140 °C. The continuous temperature variation frequency was 0.05Hz, and the pulsed electric field was applied when the temperature rose. Pulses of the electric field with widths of 10, 50, 100, and 200ms were applied to the sample under different pulse amplitudes, and the amplitude of each pulse was 250, 500, 1000, or 1500 V/mm. The maximum power generated through the application of an external pulsed electric field under the above-mentioned conditions was evaluated. This system had the highest power density of 0.204 mJ cm-2 °C-1kV-1. In addition, for the lowest input power, the maximum power generation condition was a 10ms pulse width and an amplitude of 250Vmm-1 in the applied electric field. This state might power smart sensor modules, IoT devices, automobiles, and other waste heat energy applications. Nano-pulse electric field applications may reduce input power to its lowest level, dependent on net-producing power. Therefore, new researchers can use net-generation power efficiency to create a large-scale power source using multiple pyroelectric arrays.

Experimental Study on the Effects of Applied Electric Field on Liquid Infiltration into Hydrophobic Zeolite

A nanofluidic energy absorption system (NEAS) is composed of nanoporous material and functional liquid with high energy absorption density. Applying an electric field to adjust the energy absorption characteristics of a nanofluidic system will open broader prospects for its application. In the current work, ZSM-5 zeolite was adopted as the nanoporous material and water, a 25% KCl solution, and a saturated KCl solution were adopted as functional liquids to configure NEASs. Pressure-induced infiltration experiments were carried out to study the infiltration and defiltration characteristics of the NEASs under the action of an applied electric field. The results show that the introduction of an applied electric field can weaken the hydrogen bonds between molecules, thus reducing the equivalent surface tension and contact angle, changing the infiltrability of liquid molecules into the nanopores, and reducing the infiltration pressure of the system. In an electrolyte solution/zeolite system, the anions and cations move close to the two plate electrodes under the action of an external electric field, and the fluid properties in the central zone of the pressure chamber are close to the water/zeolite system. For both an ultra-low conductivity liquid and an electrolyte solution/zeolite system, applying an electric field can effectively improve the relative outflow rate of liquid, thus improving the reusability of the system.

Investigation of osmotic shock effect on pulsed electric field treated S. cerevisiae yeast cells

Pulsed electric field (PEF) treatment is known to cause plasma membrane permeabilization of microorganisms, an effect known as electroporation. PEF treatment is very attractive since it can achieve permeabilization with or without lethal damage in accordance with desired results. This study aimed to expand the accomplishment of electroporation outcomes by applying sudden post-PEF osmotic composition change of the media. Changes in yeast cells’ viability, size and plasma membrane regeneration rate were evaluated. However, we still have questions about the intracellular biochemical processes responsible for plasma membrane recovery after electroporation. Our suggested candidate is the high osmolarity glycerol (HOG) kinase pathway. The HOG pathway in Saccharomyces cerevisiae yeasts is responsible for volume recovery after dangerous shape modifications and intracellular water disbalance caused by environmental osmotic pressure changes. Thus, we evaluated the HOG pathway inactivation effect on S. cerevisiae’s reaction to PEF treatment. Results showed that Hog1 deficient S. cerevisiae cells were considerably more sensitive to electric field treatment, confirming a link between the HOG pathway and S. cerevisiae recovery process after electroporation. By suddenly changing the osmolarity of the media after PEF we influenced the cells’ plasma membrane recovery rate, severity of permeabilization and survivability of yeast cells. Studies of electroporation in combination with various treatments might improve electric field application range, efficiency, and optimization of the process.

Application of moderate intensity pulsed electric fields in red prickly pears and soymilk to develop a plant-based beverage with potential health-related benefits

Through the last years consumers have shown a growing interest in minimally processed foods with clean labels that not only satisfy basic nutrition but also provides health-benefits. This has motivated scientists and technologists to find optimal combination of ingredients and novel technologies to produce functional products with attractive sensory properties. Red prickly pears (RPP) and soymilk (SM) have been recognized as rich sources of antioxidant compounds with health properties. Moderate intensity pulsed electric fields (MIPEF) application in plant-based foods increases phytochemicals content through stress induction or improved extraction yields. Hence, the aim of this work was to enhance the bioactive compounds content of RPP and SM by MIPEF and use them for the development of a plant-based beverage with potential health-benefits. Results indicated that MIPEF-processing increased the bioactive compounds content of RPP and SM, resulting in a plant-based beverage with higher concentration of total phenolic compounds (16%), betalains (7.2%) and isoflavones (7.4%) than the control-beverage. Furthermore, MIPEF application to the ingredients did not affect physicochemical attributes of the beverage, obtaining an appealing product with potential health-attributes. Industrial relevancePulsed electric fields processing at moderate intensities (<5 kV/cm) might be a potential way to enhance the phytochemicals concentration of plant-based ingredients used for the development of beverages with clean-labels, minimally processed and potential health benefits. This kind of products could satisfy current consumers' demand in special situations of health. However, further research must continue to better understand the mechanisms occurred during processing and to find the best processing parameters for different raw materials.

Effect of external electric fields in the charge transfer rates of donor-acceptor dyads: A straightforward computational evaluation.

We present a straightforward and low-cost computational protocol to estimate the variation of the charge transfer rate constant, kCT, in a molecular donor-acceptor caused by an external electric field. The proposed protocol also allows for determining the strength and direction of the field that maximize the kCT. The application of this external electric field results in up to a >4000-fold increase in the kCT for one of the systems studied. Our method allows the identification of field-induced charge-transfer processes that would not occur without the perturbation caused by an external electric field. In addition, the proposed protocol can be used to predict the effect on the kCT due to the presence of charged functional groups, which may allow for the rational design of more efficient donor-acceptor dyads.

Electric Field‐Induced Phase Transition on HPX6 (X = C, Si, Ge, Sn) Monolayers

Herein, the electronic, thermoelectric, and optical properties of semimetallic HPX6 (X = C, Si, Ge, Sn) monolayers are systematically studied under the influence of external electric field in the framework of density functional theory. A band tuning has been achieved in these structures by the application of an external electric field of appropriate strength. It is predicted that Dirac cone splitting is nearly proportional to the external electric field strength. The modulation of electric properties induced by external field can alter the position of chemical potential in the band diagram and brings significant improvement in thermoelectric responses. The application of an external electric field significantly modulates the optical properties. The electric field‐induced HPX6 system provides better thermoelectric and optical response for nanodevice applications.

Direct electrification of silicon microfluidics for electric field applications

Microfluidic systems are widely used in fundamental research and industrial applications due to their unique behavior, enhanced control, and manipulation opportunities of liquids in constrained geometries. In micrometer-sized channels, electric fields are efficient mechanisms for manipulating liquids, leading to deflection, injection, poration or electrochemical modification of cells and droplets. While PDMS-based microfluidic devices are used due to their inexpensive fabrication, they are limited in terms of electrode integration. Using silicon as the channel material, microfabrication techniques can be used to create nearby electrodes. Despite the advantages that silicon provides, its opacity has prevented its usage in most important microfluidic applications that need optical access. To overcome this barrier, silicon-on-insulator technology in microfluidics is introduced to create optical viewports and channel-interfacing electrodes. More specifically, the microfluidic channel walls are directly electrified via selective, nanoscale etching to introduce insulation segments inside the silicon device layer, thereby achieving the most homogeneous electric field distributions and lowest operation voltages feasible across microfluidic channels. These ideal electrostatic conditions enable a drastic energy reduction, as effectively shown via picoinjection and fluorescence-activated droplet sorting applications at voltages below 6 and 15 V, respectively, facilitating low-voltage electric field applications in next-generation microfluidics.

Surface modification of rare earth Sm-doped WO3 films through polydopamine for enhanced electrochromic energy storage performance

Electrochromic materials (ECMs) could exhibit reversible color changes upon application of the external electric field, which exhibits huge application prospects in smart windows, energy storage devices, and displays. For the practical application of ECMs, the fast response speed and long cyclic stability are urgent. In this work, the nanoporous Sm-doped WO3 (WSm) films were constructed using hydrothermal technology, then polydopamine (PDA) was modified on the surface of WSm film to obtain the WSm/Px (x = 0.25, 0.5, 1.0, and 2.0) hybrid films. WSm/Px hybrid films displayed high optical contrast and large areal capacitance. In addition, in comparison with WSm film, the WSm/Px hybrid films exhibited faster response speed and better cyclic stability because PDA film enhanced the interface ion transport ability and electrochemical structural stability of the nanoporous WSm film. Notably, the WSm/P1.0 hybrid film displayed the colored/bleached times of 7.4/2.9 s, retained 90.2% of the primitive optical contrast (68.5%) after 5000 electrochromic cycles. Furthermore, the areal capacitance of WSm film could be increased by 224% through the modification of the PDA. Therefore, WSm/Px hybrid films are great prospects for electrochromic energy-saving and storage windows.

Electric Field Control of Spin-Orbit Torque Magnetization Switching in a Spin-Orbit Ferromagnet Single Layer.

To achieve a desirable magnitude of spin-orbit torque (SOT) for magnetization switching and realize multifunctional spin logic and memory devices utilizing SOT, controlling the SOT manipulation is vitally important. In conventional SOT bilayer systems, researchers have tried to control the magnetization switching behavior via interfacial oxidization, modulation of spin-orbit effective field, and effective spin Hall angle; however, the switching efficiency is limited by the interface quality. A current-induced effective magnetic field in a single layer of a ferromagnet with strong spin-orbit interactions, the so-called spin-orbit ferromagnet, can be utilized to induce SOT. In spin-orbit ferromagnet systems, electric field application has the potential for manipulating the spin-orbit interactions via carrier concentration modulation. In this work, it is demonstrated that SOT magnetization switching can be successfully controlled via an external electric field using a (Ga, Mn)As single layer. By applying a gate voltage, the switching current density can be solidly and reversibly manipulated with a large ratio of 14.5%, which is ascribed to the successful modulation of the interfacial electric field. The findings of this work help further the understanding of the magnetization switching mechanism and advance the development of gate-controlled SOT devices.