Electric Displacement Research Articles

Features of changes in adhesiveand tribological characteristics of multilayer coatings (TiZrNbYAl)N

In this work, the adhesive and tribological characteristics of (TiZrNbYAl)N multilayer coatings were studied. The main goal of this work is to assess the influence of the number of layers on the adhesive and tribological characteristics of the (TiZrNbYAl)N coating deposited on 12Х18Н9Т steel substrates. A study of the distribution of elements over the depth of coatings using Auger electron spectroscopy showed that chemical elements are distributed quite evenly over the cross section of the coatings and the element distribution curves have sharp peaks. The presence of iron in the coating composition at a depth of more than 2 microns on the coating side indicates that an increase in electrical displacement ensures reliable adhesion of the coating to the steel substrate, which is confirmed by the results of testing the coatings for adhesive strength. An increase in the application time of each individual layer at Upp=-100 V and P= 4×10-3 Torr leads to an uneven distribution of elements throughout the thickness of the coatings and the formation of a relatively wide transition coating-substrate layer. Tests of the adhesive strength of coatings have shown that all coatings wear out when scratched, but do not peel off, i.e., they are destroyed by a cohesive mechanism associated with plastic deformation and the formation of fatigue cracks in the coating material. Different coating modes correspond to different values of acoustic emission depending on the load. It was determined that the coatings obtained at Upp =-100 V; P = 4×10-3 Torr showed high adhesive strength and some degree of delamination in the scratch area at the maximum test load. The results of tribological studies showed that (TiZrNbYAl)N coatings have a high friction coefficient, the average value of which is μ=0.85-0.95. Such values can be explained by the high roughness of wear tracks due to cohesive destruction of coatings.

Study on Bonding Performance of Magnesium Phosphate Cement Mortar in Chloride Corrosion Environment

The effects of nano‐SiO2 and hydroxypropyl methyl cellulose (HPMC) on the physical and mechanical properties of magnesium phosphate cement (MPC)‐based mortar under salt corrosion environment were studied. The variation of strength under salt corrosion environment was compared and studied. The chloride ion permeability of modified MPC mortar was evaluated by electric flux method. X‐ray diffraction (XRD) and scanning electron microscopy (SEM) were used to observe the composition and morphology of the samples under salt corrosion environment. Results showed that appropriate amount of nano‐SiO2 can significantly improve the compressive strength, flexural strength, and chloride ion penetration resistance of MPC‐based mortar under 3% NaCl solution corrosion. There existed an optimal dosage. The incorporation of HPMC would significantly reduce the compressive and flexural strength and the resistance to chloride ion penetration of MPC‐based mortar. Appropriate amount of nano‐silica and HPMC could improve the bonding performance of modified MPC‐based mortar under salt corrosion environment.

A Study on Chloride Corrosion Resistance of Reactive Powder Concrete (RPC) with Copper Slag Replacing Quartz Sand under Freeze-Thaw Conditions.

In order to study the influence of freeze-thaw cycles on chloride ion corrosion resistance of RPC with copper slag (CS) instead of quartz sand (QS), the 28d uniaxial compressive strength (UCS) of CSRPC with a different CS substitution rate was investigated by unconfined compression tests. The electric flux test method was used to study the chloride ion diffusion resistance of CSRPC after freeze-thaw cycles, and the pore size distribution was obtained through the nuclear magnetic resonance (NMR) method. Then, a mathematical relationship between the chloride ion diffusion coefficient and the pore fractal characteristic parameter T was established to study the effect of freeze-thaw cycles on chloride ion diffusion. Finally, SEM/EDS, XRD, and DTG methods were combined to study the influence of the distribution of Friedel's salts generated after freeze-thaw cycles on chloride ion diffusion in CSRPC. The results indicate that CS has a micro aggregate effect and pozzolanic activity, which can effectively improve the chloride ion diffusion resistance of CSRPC after freeze-thaw cycles. In addition, the electric flux of CSRPC decreases with the increase in freeze-thaw cycles, and the chloride diffusion coefficient is closely related to the pore fractal dimension.

Experimentation and simulation study of electromechanical response characteristics of a 2-2 type cement-based piezoelectric composite sensor

In the manuscript, the piezoelectric functional element was prepared by slicing and adding method using piezoelectric ceramic PZT-5H and ordinary silicate cement 42.5 was as base materials, and then a 2-2 type cement-based piezoelectric composite sensor was prepared by an encapsulated epoxy resin. The experimental and simulation analysis was carried out to obtain the quasi-static linear sensitivity of the electromechanical response of the sample under conditions of compressive loading. The development process of the sample from local failure to overall fragmentation was observed using a high-speed camera. Found that the electrical nonlinear threshold of 35 MPa appeared before the mechanical nonlinear threshold. Further, the results showed that when the loading frequency was increased from 5 to 15 Hz under equal amplitude, the response waveform remained unchanged, however, the electrical displacement was attenuated by 19.7%. Packaging schemes using various lengths and thicknesses of an epoxy layer were conducted by using simulation. It is indicated that, under the premise of ensuring the protection package and considering the manufacturing process, the length of the package side could increase appropriately, and the single-side package side length is set to 4 mm. When the thickness of the package layer becomes less, it would be better.

An investigation of torsional surface wave in a piezoelectric fiber-reinforced composite layer imperfectly bonded to a functionally graded half-space

This article presents a comprehensive study of torsional surface wave propagation in a piezoelectric fiber-reinforced composite (PFRC) layer bonded to functionally graded (FG) half-space considering electrically short and open boundary conditions. The Strength of Materials (SM) and Rule of Mixtures (ROM) approaches have been adopted to determine the effective properties of the PFRC. The non-ideal mechanical and electrical interfacial boundary has been considered for the problem which appears in various realistic scenarios. For the torsional surface wave propagation through PFRC bonded to FG half-space, the dispersion equation has been derived analytically using Whittaker function. The obtained results are validated and matched with existing results by considering special cases. The variation of phase velocity due to the influence of fiber volume fraction, interfacial imperfection parameters and functionally grading parameters have been analyzed and illustrated by means of graphs. Furthermore, the distribution of the field variables, stress and electric displacements across the composite are presented through surface plots. The model holds potential applications in designing and manufacturing transducers, actuators and sensors. The use of PFRC can be found in a wide range of cutting-edge technology, including vibration-canceling gadgets, energy harvesters, and pressure sensors.

ON THE METHOD OF SIMULATING A CRACK FILLER BETWEEN TWO PIEZOELECTRIC MATERIALS

A calculation model that takes into account the dielectric permeability of the crack medium is suggested for a crack at the interface of two piezoelectric materials. This model was analyzed by using the finite element method. The graphs of electric flux, displacement jumps, and electric potential distributions along the crack faces are obtained.

Pengaruh Susunan Konduktor pada SUTET

Abstract
 An effort to reduce or minimise electric field and medan magnit, a common transmission network to turn up for the conductor.But the tower transmission have some extent for environmental factors such as wind speed and construction cost to be more expensive.One of the influence of the strong electric fields magnit and the gap between its phase.How is the field of electricity and medan magnit the sutet 500 kv with this method of change the configuration of a conductor.This thesis is in the field of electricity and the horizontal magnit on the configuration, delta and vertical.The simulation done by the gap between fasanya on the configuration.From the calculation shows that if the distance between the phase changes made from 12 meters to 4.9 meters at the point of the review (0), then the magnetic flux density (B) it decreased from 6.83.10-6 be 1.58.10-6 tesla (horizontal configuration), the (delta configuration) decline of 5.9 .10-6 be 3.87.10-6 tesla tesla, and for (vertical configuration) penurunanannya of 1.12.10-5 be 6.8.10-6 tesla.While the results of the calculation of the electric field strength (E) by changing the distance between the phase from 12 meters to 4.9 meters at the point of the review (0), then there is a decrease in the electric field strength of 2.97 (kV / m) to 1.87 (kV / m) with (horizontal configuration), a decrease of 1.82 (kV / m) to 1.36 (kV / m) (vertical configuration).Likewise for delta configuration when the shortened distance between its phase, then the value of the electric field strength decreases from 0.949 (kV / m) to 0.769 (kV / m).Methods for calculating the linear regression on the delta configuration, vertical configuration, and horizontal slope (+) means that the greater the distance between the phase value of B and E increases.The resulting plot of magnetic flux density with distance between phases, the optimum value of the distance between the phase (δ) of 6.7 meters and the magnetic flux density (B) 8.03.10-6 (Tesla). While the electric field strength (E) 2.2 (kV / m). Method optimum value calculation results of electric field strength and magnetic flux density meet the standards set by WHO.
 Keywords: strong electric field, magnetic flux density, the distance between the phase and configuration

Analysis of a crack with finite electrical permeability between two piezoelectric materials

A crack with finite electrical permeability between two piezoelectric materials is investigated. Initially, it is believed that the length of the crack is much smaller than the size of the body, so the latter is considered infinitely large. Assuming that the electric flux through the crack does not change along its length, an analytical solution to the given problem is constructed. On the base of this solution the magnitude of the electric flux, as well as other components of the electromechanical fields are found. A fairly simple formula for the energy release rate (EER) is also derived. For some values of the electrical permeability of the crack medium and external loads, the amount of electric flow through the crack and EER are calculated. Approbation of the obtained results was carried out on the example of a similar problem, but for the domain of finite dimensions. The finite element method (FEM) was used and the inverse approach was applied. According to this approach, the electric flux through the crack, which is obtained analytically, is used, and the solution is carried out using FEM. The analysis of the obtained numerical results confirmed the reliability of the methodology and the obtained analytical solution.
 Keywords: crack with finite electrical permeability; piezoelectric bimaterial; analytical solution; finite element method.

A modified first-order plate theory of laminated piezoelectric plate actuators

Piezoelectric actuators with large output and high reliability are widely applied in electron device. In this paper, a modified first-order plate theory of laminated piezoelectric plates with upper and lower electrodes is presented. Then, based on the Mindlin first-order shear deformation theory, a quadratic function of electric potential across the thickness is used to describe the inverse piezoelectric effect. The laminated plate governing equations are derived in terms of the resultant force, moment and electric displacement. Further, supplementary equations are introduced through the continuity of electrical potential and the normal electric displacement across interface of each lamina, which are applied to solve the unknown electric functions in each lamina. The numerical results of displacement, deflection and electric potential are consistent with those obtained by the three-dimensional finite element method. Finally, with such a modified plate theory, regulation mechanisms of polarization direction and layer numbers are investigated on actuation properties of laminated piezoelectric actuators. It is shown that the polarization direction can change the driving displacement by an order of magnitude. It is expected that the modified theory can provide a more efficient and accurate approach for analysis of multilayer piezoelectric composite actuators.

Energy storage density and efficiency of polyetherimide nanocomposites diminished by the temperature dependent charge hopping

AbstractThe utilization of renewable energies requires extensive use of energy storage equipment such as dielectric capacitor. Polyetherimide nanocomposites (PEI PNCs) have high energy storage performance, and become the next generation advanced dielectrics However, the quantitative relation between the charge transport and energy storage of PEI PNCs is not very clear, restricting further improvement of their performance. Considering the charge injection from electrodes and the charge hopping transport inside the dielectric, the energy storage and release model of capacitors was established. Firstly, the conductivities of PEI PNCs were simulated, and the charge transport parameters were determined by comparing with the experiments. Then, the electric displacement‐electric field (D‐E) loops of PEI PNCs were simulated, and the discharged energy density and energy efficiency were calculated from them. The simulation results are consistent with the experiments, and the quantitative relationship between charge injection and transport parameters and energy storage performance is established. In addition, it is found that the energy storage density and efficiency are diminished by the increase of hopping distance at high temperatures. Increasing the hopping barrier, reducing the hopping distance and its temperature dependence through nano‐doping can significantly improve the energy storage performance under high temperatures and high electric fields.

Electric and magnetic fluxes for pseudo-hyperbolic magnetic particles

Electric and magnetic fluxes for pseudo-hyperbolic magnetic particles

Mathematical modelling for multiple straight cracks in piezoelectric ceramics

Piezoelectric materials are widely used in electronic devices like sensors. In this study, a strip saturation zone model is provided for a transversely isotropic piezoelectric plate which is cut along three equal collinear impermeable cracks. The developed saturation zones are assumed to be subjected to the linearly varying electric displacement conditions. The problem is solved using Stroh formalism and the complex variable approach. Analytic closed-form expressions are obtained for fracture parameters including crack opening displacement, crack opening potential, and saturation zone length. A numerical study also presented showing the effect of linearly varying electric displacement on the saturation zone length.

Influence of PVA fibers on the durability of cementitious composites under the wet–heat–salt coupling environment

Abstract To investigate the effects of wet–heat–salt coupling environment (WHSCE) and the content of polyvinyl alcohol (PVA) fibers on the durability of cementitious composites (CC), a series of durability tests were carried out. In this study, the salt concentration in the WHSCE was set to 5%, the temperature at 50°C, and the relative humidity at 100%. Six different contents of PVA fibers were set up in the test for exploring their effects on the durability (impermeability, chloride ion penetration resistance, freeze–thaw resistance, and chloride salt erosion resistance under dry and wet cycle conditions) of CC. The results showed that durability of CC under the WHSCE was enhanced regardless of the content of PVA fibers added. At the PVA fiber amount of 1.2%, the impermeability pressure, electric flux, mass loss rate, compressive strength loss rate, and compressive strength corrosion resistance coefficient under the WHSCE reached the optimal values. This indicated that the durability of CC was most favorable when the amount of PVA fibers was 1.2% since many engineering structures are subject to erosion by various factors in the ocean, which can inevitably affect the service life of the purchase. In this study, the effect of PVA fiber content on the durability of CC in complex environment is studied, which provides experimental data and analytical ideas for improving engineering located in the ocean, hoping to provide a theoretical basis for their subsequent application in practical engineering.

Preparation and Performance of Ultra-Fine High Activity Composite Micronized Powder from Multi-Solid Waste

The composite micronized powder is prepared by using blast furnace slag (BFS), water-quenched manganese slag (WQMS), manganese tailing slag (MTS) and desulfurization gypsum (DG) and grinding aid (GA) through orthogonal test optimization design. The effect of the doping amount of each solid waste on the fluidity, activity at different ages and resistance to chloride ion penetration of the composite micropowder was studied systematically, and the exothermic characteristics of hydration of the composite micropowder with the optimal ratio were tested. The results showed that the amount of MTS dosing was the most significant factor among the four factors on the activity index of composite micronized powder at 7 d and 28 d. The activity index at 28 d decreased and then increased with the increase in MTS dosing; the amount of BFS dosing was the most significant factor affecting the fluidity and chloride ion permeation resistance of composite micronized powder. With an increase in BFS dosing, the fluidity ratio of composite micronized powder increased and then decreased; the electric flux of the matrix decreased, and the chloride ion permeation resistance increased. The optimal ratio of composite powder with the highest 28 d activity is 35% BFS, 30% MTS, 0.3% GA, 5% DG and 30% WQMS. The hydration rate and cumulative heat release of the slurry prepared with the optimal ratio of composite micronized powder to cement (1:1) are lower than those of pure cement slurry. The microstructure of the mortar test block prepared with a 1:1 composite of cement is more compact than that of the pure cement mortar test block, and the pores are fewer.

Machine learning prediction of electric flux in concrete and mix proportion optimization design

This study explored nine machine learning (ML) methods, including linear, nonlinear and integrated learning models, to predict concrete electrical flux metrics reflecting the chloride ion permeability of concrete. Seven concrete mix parameters, including water (W), cement (C), fly ash (FA), ground granulated blast furnace slag (GGBS), fine aggregate (S), coarse aggregate (G) and water reducing admixture (WRA), were used as input parameters. A dataset consisting of 4029 sets of data was used to train and test the prediction model. K-fold cross-validation confirms the model’s accuracy and is performed by R2, MAE, MSE, and RMSE. The results showed that the nonlinear model outperformed the linear model; in particular, the model integrated with learning CatBoost exhibited higher prediction accuracy (R2 = 0.72, RMSE = 0.01, MSE = 0.01, MAE = 0.04). Based on this, a concrete chloride impermeability mix proportion optimization method targeting cost per square is proposed. The proposed model aims to achieve an ideal concrete mix proportion optimization based on ML algorithms and national specifications, which is of great significance to practical engineering.

Homological commutation relation of electric and magnetic fluxes

To give a firm base to argument on quantization of an LC circuit, we derive a commutation relation of electric flux and magnetic flux from quantum electrodynamics. The electric flux is defined by integration of electric field on two-dimensional surface. The magnetic flux is defined by integration of magnetic field surrounded by one-dimensional loop. It is proved that the commutator of the electric flux and the magnetic flux is equal to a crossing number of the loop and the surface. It is also proved that the flux commutator is invariant under gauge transformations and homological deformations. It is also argued that the LC-circuit system can be used as a platform for realizing EPR entanglement.

A Time-Domain Volume Integral Equation Solver to Analyze Electromagnetic Scattering From Nonlinear Dielectric Objects

A time domain electric field volume integral equation (TD-EFVIE) solver is proposed for analyzing electromagnetic scattering from dielectric objects with Kerr nonlinearity. The nonlinear constitutive relation that relates electric flux and electric field induced in the scatterer is used as an auxiliary equation that complements TD-EFVIE. The ordinary differential equation system that arises from TD-EFVIE’s Schaubert-Wilton-Glisson (SWG)-based discretization is integrated in time using a predictor-corrector method for the unknown expansion coefficients of the electric field. Matrix systems that arise from the SWG-based discretization of the nonlinear constitutive relation and its inverse obtained using the Padé approximant are used to carry out explicit updates of the electric field and the electric flux expansion coefficients at the predictor and the corrector stages of the time integration method. The resulting explicit marching-on-in-time (MOT) scheme does not call for any Newton-like nonlinear solver and only requires solution of sparse and well-conditioned Gram matrix systems at every step. Numerical results show that the proposed explicit MOT-based TD-EFVIE solver is more accurate than the finite-difference time-domain method that is traditionally used for analyzing transient electromagnetic scattering from nonlinear objects.

Nonlinear analysis on electrical properties in a bended composite piezoelectric semiconductor beam

In this paper, the interactions between the transverse loads and the electrical field quantities are investigated based on the nonlinear constitutive relation. By considering a composite beam consisting of a piezoelectric semiconductor and elastic layers, the nonlinear model is established based on the phenomenological theory and Euler’s beam theory. Furthermore, an iteration procedure based on the differential quadrature method (DQM) is developed to solve the nonlinear governing equations. Before analysis, the convergence and correctness are surveyed. It is found that the convergence of the proposed iteration is fast. Then, the transverse pressure induced electrical field quantities are investigated in detail. From the calculated results, it can be found that the consideration of nonlinear constitutive relation is necessary for a beam undergoing a large load. Compared with the linear results, the consideration of the nonlinear constitutive relation breaks the symmetry for the electric potential, the electric field, and the perturbation carrier density, and has little influence on the electric displacement. Furthermore, the non-uniform pressures are considered. The results show that the distributions of the electric field quantities are sensitively altered. It indicates that the electrical properties can be manipulated with the design of different transverse loads. The conclusions in this paper could be the guidance on designing and manufacturing electronic devices accurately.

Self‐Generated Displacement Current of Triboelectric Nanogenerator for Cancer Therapy: Theory and Application

AbstractWearable and implantable triboelectric nanogenerators (TENGs) convert mechanical energy to electricity in the daily movements of the human body. Self‐generated dynamic electric field or displacement current of TENGs can operate from micrometers to centimeters, which offers a key technology for TENG‐based therapy systems for precision medicine on both tissues and cells. TENGs have low‐current and high‐voltage properties, which reduce damage to normal tissues, and kill rapidly dividing cancer cells. In this work, the dynamic electric field from TENG directly inhibits the cellular proliferation behavior of cancer cells. The work paves a new way for the self‐generated electric field of TENG for cancer therapy.

Spontaneous broken-symmetry insulator and metals in tetralayer rhombohedral graphene.

Interactions among charge carriers in graphene can lead to the spontaneous breaking of multiple degeneracies. When increasing the number of graphene layers following rhombohedral stacking, the dominant role of Coulomb interactions becomes pronounced due to the significant reduction in kinetic energy. In this study, we employ phonon-polariton-assisted near-field infrared imaging to determine the stacking orders of tetralayer graphene devices. Through quantum transport measurements, we observe a range of spontaneous broken-symmetry states and their transitions, which can be finely tuned by carrier density n and electric displacement field D. Specifically, we observe a layer-antiferromagnetic insulator at n = D = 0 with a gap of approximately 15 meV. Increasing D allows for a continuous phase transition from a layer-antiferromagnetic insulator to a layer-polarized insulator. By simultaneously tuning n and D, we observe isospin-polarized metals, including spin-valley-polarized and spin-polarized metals. These transitions are associated with changes in the Fermi surface topology and are consistent with the Stoner criteria. Our findings highlight the efficient fabrication of specially stacked multilayer graphene devices and demonstrate that crystalline multilayer graphene is an ideal platform for investigating a wide range of broken symmetries driven by Coulomb interactions.