Charged Wire Research Articles

Validity of an approximate electrostatic interaction model

We explain the reasons why a simple approximate expression for the interaction energy between two parallel uniformly charged wires works so well for the calculation of the stored electrostatic energy of a uniformly charged square and/or rectangular plate. The expression under consideration was also found to be very accurate when calculating the total energy of a model consisting of an arbitrary number of uniformly charged wires placed parallel to each other along a one-dimensional regular lattice when the number of wires is not very small. One can use the derived approximate expression for the interaction energy instead of the more elaborate exact one in all circumstances where there is no need for an extremely high accuracy.

Application of integrated entropy-COPRAS and ANN approaches for maximizing wire EDM machinability attributes of Al6082-T6/GNP/TiB2 composites

Wire Electrical Discharge Machining (WEDM) utilizes electrical sparks to cut conductive materials precisely. It employs a thin, electrically charged wire to erode the material, creating complex shapes with high accuracy, tight tolerance, and minimal material waste. The current study investigates the effect of WEDM process parameters on the various output properties of machining a hybrid Aluminium metal matrix nanocomposite (HAMMNC). A series of experiments were conducted on a composite constructed using Taguchi’s standard L18 Orthogonal Array (OA) design. The acquired responses of Material-Removal-Rate (MRR), Surface-Roughness (SR), and Kerf-Width (KfW) were optimized using integrated Entropy-COPRAS and artificial neural network (ANN) algorithms respectively. The relative significance ( Qi )values obtained for the alternatives are analyzed with the Taguchi method. The outcomes showed that the optimal setting of WEDM process variables is achieved at Servo Voltage: high volts; Pulse-on-time: 60 μs; Pulse-off-time: 16 μs; Peak Current: 6 Amp; Variable frequency: 18 Hz; Speed: 50 RPM; Sim Speed: 30 RPM respectively. The models developed from ANN were adequate and accurate from the results of error histogram and regression plots and they are best suited for the prophecy of future responses. The surface morphology studies confirmed the appearance of pockmarks, voids, and globules of debris on the Wire EDMed surfaces.

Research on multi-velocity measurement method of solid particles based on interdigital electrostatic sensor

Abstract In gas-solid two-phase flow, the velocities of solid particles will show different distributions as the flow pattern changes, and it is a challenging task to achieve the measurement of different velocity parameters in the flow field. To obtain the velocity information of solid particles in the flow field, a novel method to achieve multi-velocity measurement of solid particles is proposed by using the spatial filtering characteristics of interdigital electrostatic sensor with variational mode decomposition (VMD). Firstly, a three-dimensional model of the interdigital electrostatic sensor is established using COMSOL simulation software. Based on its spatial dynamic sensitivity, a theoretical analysis of its spatial filtering characteristics is conducted to obtain a mathematical relationship for velocity measurement. Subsequently, the VMD decomposition method is applied to an experiment involving charged wires, with the experimental results verifying the effectiveness of VMD in achieving multi-scale decomposition of electrostatic signals. Finally, the proposed measurement method is validated on a gravity feeding device and a pneumatic conveying system. The experimental results demonstrate that the method exhibits good feasibility.

Electron holography observation ofelectron spin polarization around charged insulating wire.

We report direct observation by electron holography of the spin polarization of electrons in a vacuum region around a charged SiO2 wire coated with Pt-Pd. Irradiating the SiO2 wire with 300 keV electrons caused the wire to become positively charged due to the emission of secondary electrons. The spin polarization of these electrons interacting with the charged wire was observed in situ using a phase reconstruction process under an external magnetic field. The magnetic field of the spin-polarized electrons was simulated taking into account the distribution of secondary electrons and the effect of the external magnetic field.

РЕШЕНИЕ ВОПРОСА СОВМЕЩЕНИЯ СООСНОСТИ ДВУХ ПЕРЕСЕКАЮЩИХСЯ МЕТАЛЛИЧЕСКИХ ПРОВОЛОК НА ПРИМЕРЕ ИСПЫТАТЕЛЬНОГО СТЕНДА ДЛЯ МЕТАЛЛИЧЕСКОГО НАПЫЛЕНИЯ

In this work, the task was to ensure the alignment of two intersecting metal wires to maintain the welding arc at all times. This need arose as a result of an experiment in cold spray metal plating. It revealed a problem that does not allow maintaining a constant spraying process: the welding arc was unstable, because it did not ensure constant contact of differently charged metal wires. A description of the equipment used in the experiment (including both a real prototype and a three-dimensional model) and modifications of the existing mechanism to solve the identified problem is given. Also presented a general view of the modified design, as well as a separated three-dimensional model to show the fundamental design changes. As a result, a modified model of the housing, where the welding nozzles are located, has been developed. It is capable to ensure the adjustment of the welding nozzle position and, accordingly, to guarantee constant alignment of the two intersecting metal wires.

Motion of a charged particle in the electric field of a uniformly charged finite wire

Motion of a charged particle in the electric field of a uniformly charged finite wire

Fall-to-the-centre as a symmetry breaking transition

The attractive inverse square potential arises in a number of physical problems such as a dipole interacting with a charged wire, the Efimov effect, the Calgero-Sutherland model, near-horizon black hole physics and the optics of Maxwell fisheye lenses. Proper formulation of the inverse-square problem requires specification of a boundary condition (regulator) at the origin representing short-range physics not included in the inverse square potential and this generically breaks the Hamiltonian’s continuous scale invariance in an elementary example of a quantum anomaly. The system’s spectrum qualitatively changes at a critical value of the inverse-square coupling, and we here point out that the transition at this critical potential strength can be regarded as an example of a symmetry breaking transition. In particular, we use point particle effective field theory (PPEFT), as developed by Burgess et al [1], to characterize the renormalization group (RG) evolution of the boundary coupling under rescalings. While many studies choose boundary conditions to ensure the system is unitary, these RG methods allow us to systematically handle the richer case of nonunitary physics describing a source or sink at the origin (such as is appropriate for the charged wire or black hole applications). From this point of view the RG flow changes character at the critical inverse-square coupling, transitioning from a sub-critical regime with evolution between two real, unitary fixed points ( symmetric phase) to a super-critical regime with imaginary, dissipative fixed points ( symmetry broken phase) that represent perfect-sink and perfect-source boundary conditions, around which the flow executes limit-cycle evolution.

The Spacecraft Wake: Interference With Electric Field Observations and a Possibility to Detect Cold Ions

AbstractWakes behind spacecraft caused by supersonic drifting positive ions are common in plasmas and disturb in situ measurements. We review the impact of wakes on observations by the Electric Field and Wave double‐probe instruments on the Cluster satellites. In the solar wind, the equivalent spacecraft charging is small compared to the ion drift energy and the wake effects are caused by the spacecraft body and can be compensated for. We present statistics of the direction, width, and electrostatic potential of wakes, and we compare with an analytical model. In the low‐density magnetospheric lobes, the equivalent positive spacecraft charging is large compared to the ion drift energy and an enhanced wake forms. In this case observations of the geophysical electric field with the double‐probe technique becomes extremely challenging. Rather, the wake can be used to estimate the flux of cold (eV) positive ions. For an intermediate range of parameters, when the equivalent charging of the spacecraft is similar to the drift energy of the ions, also the charged wire booms of a double‐probe instrument must be taken into account. We discuss an example of these effects from the MMS spacecraft near the magnetopause. We find that many observed wake characteristics provide information that can be used for scientific studies. An important example is the enhanced wakes used to estimate the outflow of ionospheric origin in the magnetospheric lobes to about cold (eV) ions/s, constituting a large fraction of the mass outflow from planet Earth.

New solution method for the problem of a uniformly charged straight wire

A common problem in electrostatics is determining the electrostatic potential due to a uniformly charged straight wire. The solution of this problem illustrates well the types of calculations that one must perform in order to obtain the electrostatic potential or field of a given continuous charge distribution. In this work, we reconsider and solve the problem of a uniformly charged straight wire via a new method that is different from the popular direct integration approach found in the majority of physics textbooks. The outcomes of the two methods are compared and the results suggest several interesting mathematical formulas involving special functions.

Effect of hydrogen embrittlement towards thermal and mechanical behavior of NiTi shape memory alloy

NiTi arch wires are susceptible to hydrogen embrittlement upon contact with dental brackets in oral cavity during orthodontic treatment. This study investigated the effect of hydrogen absorption and diffusion over time towards the thermal and mechanical properties of NiTi shape memory wire. The hydrogen absorption process was carried out via electrolytic charging at constant current density for 16 hours in 1.0 weight percent (wt.%) sodium sulphate solution. The hydrogen charged wires were aged at room temperature in air for different durations to allow further inward diffusion of the hydrogen into the specimens. The results show that after hydrogen charging, the latent heat of forward and reverse martensitic phase transformation of the NiTi wire changed from 19.96 to 11.98 J/g, and 19.21 to 13.42 J/g, respectively. Further suppression and disappearance of thermal transformation peaks were observed as the charged specimen aged for 7 days. The transformation stress level on tensile deformation increased by almost 90 MPa after hydrogen charging, and exhibited non-flat stress plateau after further aging.

On the infinities in the electric potential of unbounded charge distributions

In every beginner electricity and magnetism course, a good teacher usually insists that if one has an infinite charged plate or an infinity charged wire, one must first calculate the electric field to find the potential difference between two space points by making a linear integral of the field. One does it this way because Coulomb’s potential, i.e. the expression which allows for a direct calculation of the potential without first calculating the electric field, should not be used since these charge distributions are not bounded in space. Due to the unbounded nature of these distributions, Coulomb’s potential diverges at all points of space in the two previously mentioned cases. However, in this work, we are going to demonstrate that in fact one can use Coulomb’s potential to find the correct results by properly removing the infinities that appear in the potential of these distributions. This is possible because electric potential, like potential energy, is only defined up to an additive constant, which in the mentioned cases can be chosen as an infinite constant. One can show that the removal of these infinities is a simple example of the renormalization techniques commonly used in quantum field theory.

Equivalence of an infinite one-dimensional ionic crystal to a simple electrostatic model

Abstract It is observed that the electrostatic potential created by the ions of an infinite one-dimensional ionic crystal at the position of a reference ion (for instance, a positive ion) is equivalent to the electrostatic potential created at the same point by a system of two identical uniformly charged straight wires each containing a charge equal to the opposite charge of the reference ion. The distance of the closest point of each wire relative to the reference ion and the length of the wires is equal to the distance separating any two adjacent ions in the regular lattice.

Geometrical interpretation of the electrostatic potential created by a uniformly charged straight wire

Uniformly charged regular bodies have always been of great interest to physics as well as to several other scientific disciplines. In this work, we consider a uniformly charged straight wire with finite length and calculate the electrostatic potential created at an arbitrary point in space. The resulting expression obtained from direct integration techniques is transformed in such a way as to lead to a very insightful geometrical interpretation. It is shown that the final result depends only on the distances of the two end points of the straight wire from of the arbitrary point of interest in space. This observation leads to the immediate identification of the nature of the equipotential surfaces around a uniformly charged straight wire.

Fall to the centre in atom traps and point-particle EFT for absorptive systems

Polarizable atoms interacting with a charged wire do so through an inverse-square potential, V = −g/r2. This system is known to realize scale invariance in a nontrivial way and to be subject to ambiguities associated with the choice of boundary condition at the origin, often termed the problem of ‘fall to the center’. Point-particle effective field theory (PPEFT) provides a systematic framework for determining the boundary condition in terms of the properties of the source residing at the origin. We apply this formalism to the charged-wire/polarizable-atom problem, finding a result that is not a self-adjoint extension because of absorption of atoms by the wire. We explore the RG flow of the complex coupling constant for the dominant low-energy effective interactions, finding flows whose character is qualitatively different when g is above or below a critical value, gc. Unlike the self-adjoint case, (complex) fixed points exist when g > gc, which we show correspond to perfect absorber (or perfect emitter) boundary conditions. We describe experimental consequences for wire-atom interactions and the possibility of observing the anomalous breaking of scale invariance.

Finite element modelling and machining using WEDM

During the past few decades, due to the demands from the production fields producing really different and compact products, there developed a need to produce materials with proper finish and with proper Material Removal Rate(MRR). So, to know the surface finish(SR) and Material Removal Rate (MRR) of a material. There are some factors effecting these both factors. In this paper we are considering WEDM (Wire Electronic Discharge Machining) as the machining equipment, WEDM is a non-conventional traditional process in which the material is being cut using a electrically charged wire which is fed continusely on to the material and by continues spread of di-electric fluid for flushing out the removed material. In the removal process there are several parameters which have to be understood in getting perfect SR and MRR. There are some fixed parameters like SEN, Material, Wire, Di-electric fluid these are the fixed parameters which can’t be changed, and the parameters which can be changed are Feed rate, Pulse-on, Pulse-off and Gap Voltage. In this paper to they performed 9-different experiments using L9 orthogonal array approach, which helps in selecting the optimized values. It’s a trail and error process, among those 9 experiments we will get one best optimized way, and we will choose those particular parameters and values chosen as the optimized values for that materialin this paper we are selecting Inconel 718 material as the work piece and molybdenum wire as the feed wire in WEDM. In the study, during machining process time taken each experiment and the weight being reduced after every experiment is being noted down, in the calculation of MRR we need this terms(weight & time), the MRR can be calculated by (Weight of the work piece before machining-Weight of the work piece after machining/Time taken). After calculating MRR and SR manually we are going to compare this values with the mathematical FEA process by using MATlab or ANSYS. In this study we came to know that Duty factor which refers to pulse-on & off time plays an important role in MRR and feed rate plays an important role in SR.

Falling of a quantum particle in an inverse square attractive potential

Evolution of a particle in an inverse square potential is studied. We derive an equation of motion for $\left<r^2\right>$ and solve it exactly. It gives us a possibility to identify the conditions under which a falling of a quantum particle into an attractive centre is possible. We get the time of falling of a particle from an initial state into the centre. An example of a quasi-stationary state which evolves with $\left<r^2\right>$ being constant in time is given. We demonstrate the existence of quantum limit of falling, namely, a particle does not fall into the attractive centre, when coupling constant is smaller then some critical value. Our results are compared with experimental measurements of neutral atoms falling in the electric field of a charged wire. Moreover, we propose modifications of the experiment, which allow to observe quantum limit of falling.

Numerical simulation of charged wire interferometer for atoms

In recent paper, Nowak et al. report a charged wire interferometer for atoms, and employ analytical method to explain the interference patterns [Phys. Rev. Lett. 81 (1998) 5792]. In this paper, a numerical calculation with semi-classical method is carried out and the experimental patterns are rebuilt very well. The interference patterns are interpreted by path integral. We also calculate the fringe period for different voltages and the agreement with experiment is more rigorous than the analytical expression. Besides, the fringe visibility of the interference patterns at different applied voltages and degrees is also discussed.

Electric field in media with power-law spatial dispersion

In this paper, we consider electric fields in media with power-law spatial dispersion (PLSD). Spatial dispersion means that the absolute permittivity of the media depends on the wave vector. Power-law type of this dispersion is described by derivatives and integrals of non-integer orders. We consider electric fields of point charge and dipole in media with PLSD, infinite charged wire, uniformly charged disk, capacitance of spherical capacitor and multipole expansion for PLSD-media.

Flow of Dusty Plasma Around an Obstacle

-Single frame video images of dusty plasmas flowing around a conducting wire are presented. The images were obtained by laser illumination of the dust suspension with the reflected light recorded using a fast video camera. Images from two different configurations are shown. The first image records the formation of a bow shock formed when a supersonic dust cloud impinges on a thin wire biased to repel the negatively charged dust. The second image shows the deflection of a thin stream of dust particles around a negatively charged wire

A Novel Way to Cleaner Combustion

The menace of SPM is more pronounced in domestic environments of rural folk who burn cheaper/low-grade fuels for cooking and heating. To counter the threats, a low-cost device has been designed and developed which has the power to trap substantial contaminants. It is a charged wire mesh which works concurrently as a filter mesh to refine the indoor environments by interrupting SPM.