Electric Potential Distribution Research Articles

Microstructural modeling on electrical conductivities of 3-D carbon/epoxy woven composites along different directions

Carbon fiber composites have widely been used in aircrafts and high speed vehicles. Electrical conductivity of the carbon fiber composites is critical to electrical safety for the aircrafts and vehicles under high voltage applications. Here we report microstructural modeling on electrical conductivities of three-dimensional (3-D) carbon/epoxy angle-interlock woven composites along on-axis and off-axis directions. A 3-D resistor network model and finite element analysis (FEA) model based on fabric microstructure have been developed to reveal the electric conductivities along different directions. We have found that the conductivity of the woven structure exhibits full anisotropy. The difference of electrical conductivity between in-plane and through-thickness direction decreased due to the existence of through-the-thickness carbon fibers. The electrical conductivity through-thickness direction increases with warp directional length. With increasing off-axis directional length, the conductivity perpendicular to the off-axis direction increases, while the conductivity parallel to the off-axis direction remains basically unchanged. Electric potential distribution and electrical current density are highly related with fabric structure and current directions. Owing to the dependence of mechanical properties are also related with fabric structure and directions, it is expected that both the electrical and mechanical properties of the 3-D woven carbon/epoxy composites could be optimized simultaneously from the composite microstructure designs.

Mechanically induced electric potential and charge redistribution in laminated composite piezoelectric semiconductor circular cylindrical thin shells

We study electromechanical effects and piezotronic behaviors in a Kirchhoff–Love laminated composite piezoelectric semiconductor circular cylindrical thin shell, which is composed of a non-piezoelectric semiconductor core and two piezoelectric dielectric layers. A second-order assumption for electric potentials and carrier concentration perturbations is utilized to capture accurate descriptions of the electric field and charge distributions within the composite shell, where the zeroth-order, first-order, and second-order forms represent constant, antisymmetric, and symmetric distributions along the thickness, respectively. The field equations and boundary conditions are simultaneously derived through a principle of virtual work and the fundamental lemma of the calculus of variation. The new governing equations derived show a new coupling relation between mechanical deformation and charge behavior in the composite shell, where all mechanical deformations (extension, bending of the shell) and all distribution forms of electric potential (zeroth-, first-, second-order electric potentials) are coupled, which is different from piezoelectric semiconductor beams and plates. Then, the numerical results of electromechanical effects and piezotronic behaviors in static bending and forced vibration problems of the shell are conducted with the derived theoretical model. Numerical studies of static bending graphically show some fundamental coupling relations between mechanical forces and charge distributions in deformed piezoelectric semiconductor shells. The new results from the forced vibration analysis given by the current model show that the deflection amplitude and the electric potential distribution in the thin shell are frequency-dependent and can be adjusted by controlling the excitation frequency. In addition, the semiconducting properties (dependence of mechanical behavior on doping level) are studied in both static and dynamic problems. The mechanically controlled charge distribution suggests that shell-shaped piezoelectric semiconductor shells could serve as an effective means of sensing or energy harvesting by converting mechanical energy into electricity.

Ferroelectric Domain Wall p-n Junctions.

We have used high-voltage Kelvin probe force microscopy to map the spatial distribution of electrical potential, dropped along curved current-carrying conducting domain walls, in x-cut single-crystal ferroelectric lithium niobate thin films. We find that in-operando potential profiles and extracted electric fields, associated with p-n junctions contained within the walls, can be fully rationalized through expected variations in wall resistivity alone. There is no need to invoke additional physics (carrier depletion zones and space-charge fields) normally associated with extrinsically doped semiconductor p-n junctions. Indeed, we argue that this should not even be expected, as inherent Fermi level differences between p and n regions, at the core of conventional p-n junction behavior, cannot occur in domain walls that are surrounded by a common matrix. This is important for domain-wall nanoelectronics, as such in-wall junctions will neither act as diodes nor facilitate transistors in the same way as extrinsic semiconducting systems do.

The Results Comparison of Numerical and Analytical Methods for Electric Potential on Rectangular Pipes

Two methods can be used to solve the problem of electric potential distribution in a rectangular pipe: numerical and analytical. The analytical solution is obtained using the Laplace equation and the given boundary conditions to complete the solution in the form of a linear combination of sinusoidal and hyperbolic functions. While the numerical solution is obtained using the finite difference method in the Python programming language. The comparison between the analytical and numerical solutions shows that the two have a good fit. This can be seen from the graph of the electric potential distribution in the rectangular pipe produced by the two methods. Numerical solutions obtained using the finite difference method in the Python programming language provide accurate and efficient results in solving the problem of the electric potential distribution in rectangular pipes. The use of the first four terms in the analytical method and the selection of 4 observation points on the pipe, namely points A (3.33, 1.67), B (3.33, 3.34), C (6.67, 1.67), and D (6.67, 3.34) produces a difference in the electric potential value between analytical and numerical methods each point is 35.91%, 51.96%, 51.96%, and 35.91%. The value difference between analytical and numerical methods will be smaller if more terms are taken in the analytical calculation, and more observation points are considered on the pipe.

Paint Film Formation Characteristics on Conical Surfaces for Electrostatic Air Spray Painting

When a curved target surface is coated in an electrostatic spray-painting process, the paint film pattern on curved targets will deform, and the thickness will change compared with the planar target due to the curvature characteristics of the target, the inhomogeneous electric field, and the flow field. Therefore, directly using the planar deposition distribution for painting the trajectory planning of curved surfaces causes large errors and low paint transfer efficiency. A study investigating the curved surface paint film thickness distribution characteristics is presented in this research to understand the relations among the target surface curvature, the electrostatic field, and the flow field distribution. Spray-painting process simulations were performed for conical surfaces of different curvatures. Moreover, the paint particle’ trajectories, electric potential, and film deposition distribution were computed using ANSYS Fluent. The paint transfer efficiencies of these targets were computed. The results show that when the generatrix curvature of the conical surface increases gradually, the electric field intensity near the wall increases, which enhances the deposition of charged droplets on the wall. Moreover, the airflow field velocity increases as the curvature increases, which leads to a large diffusions of the spray flow field, so the paint thickness decreases, and the transfer efficiency is low.

Electromechanical behavior and damage index system of 3D carbon fiber angle-interlock woven composites with FEA and data processing tools

The relationship between structural damage and electrical resistance change of carbon fiber reinforced composites is important to structural health monitoring. Here, we investigated the electromechanical behavior and damage index system for identification of various damage types in 3D angle-interlock woven composites under tensile loading in the warp direction. The mechanism of electrical resistance change was explored by combining current injected from both ends (Electrical current is in the plane of the laminate and goes through the entire cross section of the specimen) and current injected diagonally (Direction of electrical current between the in-plane direction and the through-thickness direction). A finite element model was established to analyze the electric potential distribution and tensile damage evolution process of composites. We found current injected from both ends can only detect with yarn damage and current injected diagonally can detect with matrix cracks, interface cracking and yarn damage. Based on the electrical resistance data of current injected diagonally, we used principal component analysis and K-means clustering methods to establish a damage index system to reflect the damage accumulation degree of different damage modes. The finite element analyses verified the rationality of the damage index system.

Non-invasive current collectors for improved current-density distribution during CO2 electrolysis on super-hydrophobic electrodes

Electrochemical reduction of CO2 presents an attractive way to store renewable energy in chemical bonds in a potentially carbon-neutral way. However, the available electrolyzers suffer from intrinsic problems, like flooding and salt accumulation, that must be overcome to industrialize the technology. To mitigate flooding and salt precipitation issues, researchers have used super-hydrophobic electrodes based on either expanded polytetrafluoroethylene (ePTFE) gas-diffusion layers (GDL’s), or carbon-based GDL’s with added PTFE. While the PTFE backbone is highly resistant to flooding, the non-conductive nature of PTFE means that without additional current collection the catalyst layer itself is responsible for electron-dispersion, which penalizes system efficiency and stability. In this work, we present operando results that illustrate that the current distribution and electrical potential distribution is far from a uniform distribution in thin catalyst layers (~50 nm) deposited onto ePTFE GDL’s. We then compare the effects of thicker catalyst layers (~500 nm) and a newly developed non-invasive current collector (NICC). The NICC can maintain more uniform current distributions with 10-fold thinner catalyst layers while improving stability towards ethylene (≥ 30%) by approximately two-fold.

Start-Up Multilayer Electro-Osmotic Flow of Maxwell Fluids through an Annular Microchannel under Hydrodynamic Slip Conditions

The present investigation analyzes the transient multilayer electro-osmotic flow through an annular microchannel with hydrophobic walls. The fluids are considered immiscible and viscoelastic, following the Maxwell rheological model. In the problem examined, the linearized Poisson–Boltzmann and Cauchy momentum equations are used to determine the electric potential distribution and the flow field, respectively. Here, different interfacial phenomena are studied through the imposed boundary conditions, such as the hydrodynamic slip and specified zeta potentials at solid–liquid interfaces, the velocity continuity, the electroviscous stresses balance, the potential difference, and the continuity of electrical displacements at the interfaces between fluids. The semi-analytic solution uses the Laplace transform theory. In the results, the velocity profiles and velocity tracking show the oscillatory behavior of flow, which strongly depends on the dimensionless relaxation time. Furthermore, the hydrodynamic slip on the channel walls contributes to the release of energy stored in the fluids due to elastic effects at the start-up of the flow. Similarly, other dimensionless parameters are also investigated. This research aims to predict the parallel flow behavior in microfluidic devices under electro-osmotic effects.

Extended Theory and Analysis of Potential Applications of Gauss's Law

This article analyzes and discusses the extended theory of Gauss's law and its potential applications in different fields. In the theoretical foundation section, the article elaborates on the definition, theory, and formulas of the traditional Gauss's law, providing mathematical derivations. Additionally, it reviews the applications of Gauss's law in electrostatics and gravitational fields, including aspects such as electric field flux, electric potential displacement, gravitational field, and mass distribution. In the potential application analysis section, the article explores the potential applications of Gauss's law in fields such as communications, acoustics, and medicine The expanded theories and potential applications of Gauss's theorem provide us with a unified mathematical framework at the macroscopic level for describing and explaining physical phenomena in different fields. By applying Gauss's theorem and its extended forms, we can better understand and explore various phenomena in the natural world, applying them to acoustics, medicine, and scientific research, thus advancing technological development and addressing practical problems.

Phase-field simulation of interface growth of magnesium metal anodes during electrodeposition

Mg-metal has abundant reserves and extremely high-volume capacity, making it an excellent choice as the negative electrode for low-cost, high-volume energy-density batteries. More and more studies have shown that there is still a problem of dendritic growth in Mg-metal. Here, we use the open-source MOOSE software package to establish a phase-field model for Mg-electrodeposition and study the dynamic morphological evolution of the growth of Mg-metal anode interfaces under different overpotentials in two dimensions. By studying the temporal-spatial distributions of ion concentration, chemical potential, and electric potential, we analyze the growth processes of Mg-metal anode interfaces under different applied overpotentials in detail. The results show that the Mg-metal anode interfaces only grow dendrites under applied overpotentials ranging from −0.24 to −0.30 V because the interface electrochemical reactions rate is greater than the interface ion transfer rate.

Two-Dimensional Distribution of Plasma Electric Potential in the T-10 Tokamak

Heavy ion beam probe (HIBP) is a unique plasma diagnostics that makes it possible to measure the electric potential φ of high-temperature plasma and its fluctuations y, as well as the density ne and poloidal magnetic field Bpol fluctuations. Position of the point of performing measurements in the plasma vertical cross-section depends on the beam energy and angle of its entrance into the plasma. The variation of these two parameters makes it possible to construct a two-dimensional (2D) detector grid, which covers the domain of possible measurements. The measurement results obtained in the detector grid points provide for constructing 2D distributions of plasma parameters. For the OH and ECRH stages of the T-10 tokamak shots, 2D distributions of the plasma electric potential are presented for the regime with the on-axis magnetic field of Bt = 2.2 T, plasma current of Ipl = 230 kA, line-average density of ne ≈ 1.1 × 1019 m–3 and off-axis ECRH power of PECRH = 1.7 MW.

Two-Dimensional Distribution of Plasma Electric Potential in the T-10 Tokamak

Two-Dimensional Distribution of Plasma Electric Potential in the T-10 Tokamak

Features of the Electrical Properties of Limited Diffusion Semiconductors in Contact Measurements

The purpose of this work is to study the features of the electrical properties of bounded semiconductors, as well as the effect of the inhomogeneous distribution of impurities in anisotropic semiconductors on the structure of electric fields with standard methods of contact measurements.Diffusion and ion-doped semiconductor structures, as well as composite structures with misalignment of film and substrate lattices, are currently a promising class of materials in micro- and nanoelectronics. The introduction of an impurity into a semiconductor crystal sample changes its electrical properties, which makes it possible to reduce the size of individual components of the chip, while maintaining or increasing their power.Methods. The results of the work are based on the known dependences of the distributions of impurities during diffusion alloying. To calculate the potential distribution, the Fourier method was used, which made it possible to solve the Poisson Equation with Neumann boundary conditions without approximations. The mathematical package MathCad was used to analyze the obtained expressions characterizing electric fields in inhomogeneous semiconductors.Results. A technique for solving the boundary value problem for the potential in bounded diffusion semiconductors is presented. Expressions in the form of series of analytical functions for the distribution of electric potential in conducting anisotropic structures are presented. The constructed models make it possible to determine and qualitatively describe the distributions of electric fields during probe measurements and to investigate their structure in diffusion semiconductors. Conclusion. On the basis of computer modeling, the importance of taking into account the parameters of inhomogeneity of conductivity is shown. The effect of concentration of current density lines in diffusion semiconductors is shown and quantified.

The impact of lithiated active binder on Li-ion battery charge–discharge and rate capability, Part II: Mesoscale modeling of LCO based Half-cell

Even though thick electrodes are essential to increasing the energy density of LIBs, high current rates cause them to lose power density due to high polarization and ion depletion in the pore spaces. Mixed active binders with lithiated bound charges can improve the battery capacity and voltage at high C-rates, even compared to similar high concentrated electrolyte. The lithiated binders also provide a more uniform spatial distribution of intercalation reaction current, electric potential, and open circuit potential. The LIB half cell is modeled at mesoscale by taking into account the diffusion–reaction physics of the bound charge mixed electrolyte in active carbon-binder-domain (CBD), that accounts the dissociation of anionic ligands. Electrolyte in separator and active CBD are coupled by Donnan theory at the interface, and the reaction interfaces are modeled by the standard Butler–Volmer equation. By means of a thermodynamically consistent model and its implementation in a FEM code, we investigate the impact of particle distribution, electrode thickness, and separator thickness for both standard binder and active binder mixed cathodes in terms of ion depletion, current density, and electric potential. This mathematical model can also be extended to the modeling of ion conducting polymer electrolytes, gel polymers, and other conductive materials for battery applications.

Uniplanar multirod TDR probe for soil water content measurement over a larger spatial scale

AbstractThis study developed a uniplanar multirod time domain reflectometry (TDR) probe and evaluated it in laboratory experiments for soil water measurement over a larger spatial scale. The sampling volume of the probe was determined by simulating the electric potential distribution around the probe rods by using the HYDRUS‐2D software package and verified by comparison with the measured dielectric constant in saturated sand. The performance of the probe was evaluated by comparing its dielectric measurements in wet sand over a wide range of water content during evaporative drying with that measured by CS640 probes. Additionally, the dependency of visible light reflection on the water content of the sand was evaluated. The results revealed that the average effective thickness of the probe's sampling volume was 5–6 cm on both sides of the plane of the probe rods. The probe accurately measured the soil water content over a 0.88 m2 spatial area. The visible light reflectance of the variably saturated sand surface and the corresponding water content of the sand follow a soil water retention function‐type relationship. The usage of the multirod TDR measurement system at a larger spatial scale carries practical implications, especially in increasing the accuracy of remote sensing data.

Computation of Electric Field and Potential Distribution of 110KV Polymer Insulator

The electric field (E-Field) and potential distribution are more important in deciding the lifetime of the insulator. Different climate conditions and several pollution conditions lead to the deterioration and degradation of the insulator's properties, increasing the electric stress and exceeding the threshold value during long working conditions, leading to the failure of the insulator. This project mainly focuses on improving the reduction of electric stress by using different side positions of the corona ring an optimizing corona ring placement on a 110 kV AC transmission line composite insulator. The Corona ring plays a significant role in the reduction of electric stress. Analyze the performance of three different positions of the corona ring: HV and LV side, LV side, and HV side, and implement the three different optimizations in the Bobyqa, Nelder-Mead, and Cobyla optimizations to achieve uniform distribution. The results show that HV-side corona ring placement significantly reduces electric stress, and Bobyqa optimization greatly reduces electrical stress compared to other optimization techniques.

Boosting Wavelength‐Selective Absorption and Photocarrier Collection in NiO/ZnO Transparent Photovoltaic Heterojunctions by Plasmonic Ag Nanowire Top Electrodes

AbstractGlobal climate change has compelled many to rely on photovoltaic (PV) technology to meet the highly demanding energy needs of urban areas. In particular, transparent photovoltaic (TPV) devices can be utilized for building windows, not only supplying electric energy but also improving the overall thermal efficiency of a building. In this work, NiO/ZnO wide‐bandgap oxide TPV heterojunctions are fabricated with Ag nanowire (NW) top electrodes and their PV characteristics are investigated. Special attention is paid to the contributions of surface plasmon (SP) excitation in AgNWs to the PV performance of the TPV device. Light polarized perpendicular to the AgNW axis induces a localized SP resonance in AgNWs at a wavelength of 400 nm, as shown by optical measurements and calculations. The investigation on how the plasmonic AgNWs affect real‐space electric potential distributions and local current‐voltage characteristics of the TPV devices uses Kelvin probe force microscopy and current‐sensing atomic force microscopy, respectively. The spatial redistribution and transport of photogenerated charge carriers strongly depend on the polarization as well as the wavelength of incident light. The results demonstrate that the AgNW‐based top electrodes boost the wavelength‐selective absorption and the effective collection of photocarriers in TPV devices.

Geometric eccentricity effect on thickness-shear vibration of an elliptical flexoelectric crystal plate

In this paper, a thickness-shear vibration model for a two-dimensional finite flexoelectric crystal plate with slowly varying thickness and elliptical cross section is presented. The influences of eccentricity and flexoelectricity on the fundamental frequencies of thickness-shear vibration and electric potential distributions under short circuit boundary condition are investigated. The proposed model uses the first order McLaughlin series to approximate the elliptical function and the first derivative of elliptical function is ignored since the plate thickness varies slowly. For the finite plate, the symmetric mode in length and antisymmetric mode in thickness are adopted for the displacement function. In addition, only the shear strain gradient through the thickness is used in the mathematical model for the thin and long flexoelectric crystal plate. By implementing the variational principle, the governing equations are obtained and further solved by the Galerkin method. The obtained frequencies of thickness-shear mode are expressed in terms of eccentricity and length-to-thickness ratio. The results show that the eccentricity has great influence on the nondimensional fundamental frequencies. A small reduction in eccentricity results in significant increment of the nondimensional frequency implying that it is possible to increase the fundamental frequency by changing the cross section of the elliptical flexoelectric plate. The flexoelectric effect is also found to affect the nondimensional frequency and electric potential distribution significantly. Thus, for accurate design of nano/micro scale high precision and high frequency flexoelectric/piezoelectric devices, flexoelectricity must be taken into consideration.

Spectroscopic characterization, DFT study, topological, molecular docking and pharmacological analysis of Iminodiacetic acid Hydrochloride

Iminodiacetic Acid Hydrochloride (IAH) optimum geometries and vibration spectra have been determined by density functional theory computations at B3LYP with 6-311++G(d, p) level basis functions. Finding the most stable structure of IAH is done through conformational analysis. In order to interpret IR and Raman spectra both quantitatively and qualitatively, vibrational spectra have been examined based on the potential energy distribution (PED) within each vibrational mode. By means of calculations both theoretical and experimental, UV–Visible and NMR spectral studies of IAH have been performed. Utilising NBO analysis, stabilisation resulting from inter- and intramolecular interaction has been studied. For predicting the reactivity and stability of the molecule, chemical reactivity descriptors are computed. Molecule size, shape, electrical potential distribution, and point of chemical reactivity will all be revealed by mapping the charge density isosurface well with electrostatic potential surface (ESP). ELF and LOL maps intended topological aspects of IAH have also been depicted. Additionally, the Natural atomic charge and the hyperconjugative interactions that cause its NLO activity have been predicted. The hyper polarizability values indicate that these compounds could be used in electro-optical applications. IAH is screened for its pharmacological activity. The binding location of the molecule to its target protein has been predicted via a molecular docking study.

Hydrodynamics and electrical insulation of PbLi flow with SiC flow channel inserts in a strong magnetic field

Experimental and numerical research in a strong magnetic field is described in this article testing silicon carbide (SiC) flow channel inserts (FCI) in lead-lithium (PbLi) liquid metal flow. The study aims to further develop the High-Temperature Dual-Coolant Lead-Lithium nuclear fusion blanket concept by testing new variations of SiC inserts operating in the relevant electromagnetic conditions. These inserts act as electrical insulators in magnetohydrodynamic lead-lithium flow and can also play the role of the thermal insulator in the potentially real fusion environment. The liquid metal pressure and integral flowrate measurements were performed on up to 5T DC magnetic field created by a superconducting magnet at high temperatures up to 700 °C, which is close to the real fusion environment. Comparisons of several cases with and without inserts are provided, demonstrating their impact on hydraulic resistance. Additionally, electrical potential distribution is recorded on the lead-lithium channel walls, which can be used to evaluate the character of liquid metal velocity distribution in the lead-lithium channel.