Investigation of Coulomb force effects on ethylene glycol based nanofluid laminar flow in a porous enclosure

Forced convection heat transfer of ethylene glycol based nanofluid with FeOinside a porous medium is studied using the electric field. The control volume based finite element method(CVFEM) is selected for numerical simulation. The impact of the radiation parameter(R), the supplied voltage(?φ), the volume fraction of nanofluid(?), the Darcy number(Da), and the Reynolds number(Re) on nanofluid treatment is demonstrated. Results prove that thermal radiation increases the temperature gradient near the positive electrode. Distortion of isotherms increases with the enhance of the Darcy number and the Coulomb force.

Influence of Coulomb force between two electrons on double ionization of He-like atoms

In strong-field double ionization,two electrons are ionized by intense laser field.These two electrons move in the laser field and the state is described by a Coulomb-Volkov state,where the repulsive Coulomb state describes the relative motion of the two electrons and the Volkov state describes the center-of-mass motion of the two electrons in the laser field.In the frame of scattering theory,we derive a simple analytical formula of the double ionization of He-like atoms.The effect of the Coulomb force between two electrons on the double ionization process is discussed.Numerical studies disclose that the Coulomb force enhances the ionization rate of high-energy electrons but suppresses the ionization rate of the lowest-energy electrons.

Transport of Relativistic Electrons Scattered by the Coulomb Force and a Thermionic Energy Converter with a Built-in Discharge Tube

A transport equation of momentum for relativistic electrons scattered isotropically was previously reported. Here, a momentum-transport equation for relativistic electrons “scattered anisotropically” by the Coulomb force is inquired into. An ideal plasma consisting of electrons and deuterons is treated again. Also, to raise a generation-ability of a thermionic energy converter, a means of introducing external electric and magnetic fields within “a converter in which an emitter plate and a collector plate face simply each other” is proposed.

INTERACTION OF ELECTRIC CHARGES IN A PIEZOELECTRIC WITH RIGID EXTERNAL CRACKS

Using Stroh＇s formalism the simple explicit expressions of Green＇s functions for a 2D piezoelectric body with two semi-infinite fixed conductor cracks subjected to a generalized line force were given. The Coulomb force acting on the free line charge aroused by the piezoelectricity and the distributed boundary polarization charges was discussed at first. Interactions between two singularities with free charge （s） located in a region with external cracks were studied, too. The numerical results show that the Coulomb force for two or more singularities with one free charge at least will have much influence on the electromechanical fields in piezoelectric media when these singularities move closely with each other and therefore cannot be overlooked again. The solutions obtained are valid not only for plane and anti-plane problems but also for coupled problems between in-plane and out-of-plane deformations.

GREEN'S FUNCTIONS FOR 2D PROBLEMS OF ANISOTROPIC PIEZOELECTRIC MATERIAL WITH A STRIP REGION

By using Stroh's formalism and the conformal mapping technique,we derive the simple ex- plicit elastic fields of a generalized line dislocation and a generalized line force in a general anisotropic piezo- electric strip with fixed surfaces,which are two fixed conductor electrodes.The solutions obtained are usually considered as Green's functions which play important roles in the boundary element methods.The Coulomb forces of the distributed charges along the region boundaries on the line charge q at z^0 are analysed in detail. The results are valid not only for plane and antiplane problems but also for the coupled problems between in- plane and outplane deformations.

AN ANALYSIS OF 2D PIEZOELECTRIC HALFPLANE WITH A FIXED CONDUCTOR SURFACE

Solutions to a piezoelectric half-plane with a fixed conductorsurface electrode subjected to two generalized singularities (linedislocation and/or lien force and free charge) are presented.Coublomb forces acting on the singularities due to the boundarypolarization changes of medium and the induction charg- es ofconductor electrode are analyzed in detail. The interaction betweenthe two singularities is also analyzed numerically. Results show thatCoulomb forces will become important as the free change approachesthe boundary or two singularities move closely.

Magnetic Charge Theory. Part 3: Neutron Structure and Dark Matter Source

The concept of magnetic charge is further developed to explain the electron/proton magnetic bonding that forms the neutron. The derivation leads to a minimum range for the Coulomb force of 2.35 fm that explains the lack of the Coulomb force in the nucleus. Further investigation into the nature of gravity leads to the possibility that dark matter is a byproduct of stars.

Electron Transport under the Influence of Two Kinds of Friction in an Electron-Deuteron Plasma

We discuss an electron transport in an ideal plasma which consists of electrons and deuterons. With respect to a frictional force to suppress an unlimited increase of a drift velocity, the Boltzmann equation with the Fokker-Planck collision term takes into consideration only a dynamical frictional force coming from the many-body collisions through the Coulomb force. However, we here bring forward a problem that there may be another frictional force besides the dynamical frictional force. Another frictional force was found in the weakly ionized plasma and appears only in the case where free paths (nearly straight lines in no external force field) can be defined. Then, we have inquired into the existence of physical quantities like free paths (or free times) in the field of the scattering through the Coulomb force and the existence of an effective radius of the Coulomb force of a deuteron.

Actual Sensing Sensitivity and SNR Measurement of Optical Tweezers Based on Coulomb Force Input

Sensing sensitivity is the key performance of optical tweezers.By adjusting the frequency and magnitude of an applied Coulomb force as an input of optical tweezers,we directly measured the sensitivity and signal-to-noise ratio(SNR)of a system and indirectly calculated the actual noise magnitude.Combined with an output filter,the relationship between the SNR and bandwidths was studied.We established the simulation model of a system using Simulink and simulated the relationship between the SNR and magnitude of the input forces and filter bandwidths.In addition,we built an experimental system to determine the relationship between the SNR and the magnitude of the input forces and filter bandwidths.The actual minimum detectable force was measured as 1.8275×10^(-17)N at a 1Hz bandwidth.The experimental results were correlated with the simulation and theoretical results,confirming the effectiveness of the proposed method and demonstrating the high sensitivity of vacuum optical tweezers as mechanical sensors.We proposed a novel method of calibration and measurement of system sensing parameters by applying an actual force that was more direct and precise than the theoretical calculation method that requires accurate fitting parameters,such as the particle radius and density.This method can be employed to analyze the system noise and phase characteristics to confirm and improve the real performance of the system.

Coulomb, Yukawa, and Hooke’s Oscillations

Oscillations due to three different forces in three areas of physics: electrostatic, nuclear, and mechanics, are analyzed. The electrostatic long-range Coulomb force has a different character than the nucleonic short-range Yukawa force. Both are different from the linear Hooke’s force. The equation of motion of each case is solved applying a Computer Algebra System (CAS). It is shown that these oscillations have similarities and differences. Phase diagrams of all three cases are compared.

Estimation of automotive brake drum−shoe interface friction coefficient under varying conditions of longitudinal forces using Simulink

The suitable brake torque at the shoe-drum interface is the prerequisite of the active safety control.Estimation of accurate brake torque under varying conditions is predominantly the function of friction coefficient at the shoe-drum interface.The extracted friction coefficient has been used in the antilock braking system(ABS)algorithm to plot the μ-slip curve.The longitudinal forces like Coulomb friction force,contact force and actuating forces at the shoe ends are resolved under the equilibrium condition.The computation of the friction coefficient is presented for the symmetric and asymmetric length of the drum shoes to track the variations in the longitudinal forces.The classical mechanics formulae considering friction are simulated using virtual environment in Matlab/Simulink for the distribution of the Coulomb force.The dual air braking system set up operated at the 8 bar pressure is used to acquire data for the input parameters like distance of Coulomb friction force,distance of pivot point,and contact force applied.The evolved estimation algorithm extracted the maximum friction coefficient of 0.7 for the normal force arrangement of the contact force at the symmetric shoe length,while friction coefficient in the range of 0.3-0.7 is obtained at the asymmetric shoe length.

Comparing the force due to the Lennard-Jones potential and the Coulomb force in the SPH Method

Seventy years after the Smoothed Particle Hydrodynamics(SPH)method was created,there was the need to use the solid limit to keep the domain particles of a certain region.This boundary’s treatment is usually done with the use of force derived from potential Lennard-Jones.In our paper,a new boundary treatment technique is presented.Now,we use the Coulomb force to exert a repulsive force on the border to avoid outgoing particles leaving the simulation domain.To test this new technique,the problem of dam break and sloshing was simulated.©2018 Shanghai Jiaotong University.Published by Elsevier B.V.