Maxwell Electromagnetism Research Articles

Design of a torque sensor based on piezoelectric torsional effect of quartz pillar

PurposeTorque is one of the main parameters reflecting the operation status and detection of a mechanical rotation system. The use of quartz pillar to design torque sensors has advantage over the use of quartz disk, but research into the torsional effect of quartz pillar is rare. This paper aims to investigate a novel type of torque sensor based on piezoelectric torsional effect.Design/methodology/approachBased on the theory of anisotropic elasticity and the Maxwell electromagnetism, the torsion stress and distribution of surface charge of a rectangular quartz pillar are calculated. Using finite element analysis, the polarized electric field of the piezoelectric pillar is solved. According to the theoretical calculation of torsional effect of piezoelectric quartz pillar, detection electrodes are mounted on the surface of the quartz pillar and a new type of torque sensor is designed.FindingsThe calibration experimental results show that the bound charges are proportional to the torque applied, and the torque sensor has fully reached the dynamometer standard.Originality/valueThis paper shows that the torsional effect of the developed piezoelectric quartz pillar can be used to create a new type of piezoelectric torque sensor.

Study the Effect of Suction-Injection parameters Numerically and Analytically for Magneto hydrodynamic Jeffery Hamel Fluid Flow Problem

This paper processes numerically and analytically the magnetohydrodynamic flow among two porous solid plate intersections at an angle or through non-parallel porous walls, which can be interpreted as a mix of Jeffery Hamel fluid flow additives from suction-injection parameters. In fluid mechanics, the equations of governing, which are transferred to the non-linear ordinary differential equation of third order, are modeled instead of the conventional Navier-Stokes equations by Maxwell's electromagnetism. Results obtained from the DTM and the numerical method BVP4c are compared to those resulting from the optimal methods (ODTM), which consist of the collocation differential transform method (CDTM), the sub-domain differential transform method (SDTM), the least squares differential transform method (LSDTM), and the Galerkin differential transform method (GDTM). A comparison is made between the approximate analytical and numerical solutions for different parameters like open angles (ε), Reynolds numbers (Re), injection parameters (S), and Hartmann numbers (Ha). The results demonstrate that the two approaches are very similar.

Lagrangian reverse engineering for regular black holes

Nonlinear extensions of classical Maxwell's electromagnetism are among the prominent candidates for theories admitting regular black hole solutions. A quest for such examples has been fruitful, but mostly unsystematic and littered by the introduction of physically unrealistic Lagrangians. We provide a procedure which admits the reconstruction of a nonlinear electromagnetic Lagrangian, consistent with the Euler–Heisenberg Lagrangian in the weak-field limit, from a given metric representing a regular, magnetically charged black hole.

Plebanski-Demianski goes NUTs (to remove the Misner string)

We present a general procedure, based on the Ehlers transformation of the Ernst equations, to add the gravitomagnetic mass to the whole Plebanski-Demianski family of solutions. We can efficiently generate a large class of accelerating black holes, such as Reissner-Nordstrom or Kerr-Newman, endowed with the NUT parameter. The full rotating version carries a couple of independent NUT charges, one associated to the black hole and the other to the accelerating Rindler background.The two NUT parameters can be coupled to remove the axial irregularity which causes the Misner string, still remaining with a Lorentzian spacetime, without the need to impose periodic time.All the metrics we build are not of D-type according to the Petrov classification, but type-I, so they belong to a more general category with respect to C-metrics and the Plebanski-Demianski seed.A convenient form of the most general type D black hole solution in general relativity, coupled with Maxwell electromagnetism, is obtained when switching off one of the two NUT parameters.

The cracks of classical mechanics and the Birth of quantum mechanics

At the end of the 19th century, with the development of Newton's classical mechanics and Maxwell's electromagnetism, a great number of individuals believed that the laws of physics had reached the point of perfection. Physicists like Pierre-Simon Laplace even thought that Newtonian mechanics could be used to calculate the future. However, the "dark clouds" such as the Michelson-Morley experiment and black body radiation demonstrated the flaws of the classical theory. With the efforts of quantum mechanics pioneers such as Planck, Einstein, Schrodinger, and Heisenberg, the discipline of quantum mechanics has gradually developed and has become the key to opening the door to the microscopic world. This paper demonstrates the cracks that occurred in classical physics at the end of the 19th century, and then illustrates the birth of the quantum mechanics and some of the most important concepts of it. Finally, some cutting-edge technologies related to quantum are introduced.

Probing axions through tomography of anisotropic cosmic birefringence

Cosmic birefringence is the in-vacuo rotation of the linear polarization plane experienced by photons of the Cosmic Microwave Background (CMB) radiation when theoretically well-motivated parity-violating extensions of Maxwell electromagnetism are considered. If the angle parametrizing such a rotation is dependent on the photon's direction, then this phenomenon is called Anisotropic Cosmic Birefringence (ACB). In this paper, we perform for the first time a tomographic treatment of the ACB, by considering photons emitted both at the recombination and reionization epoch. This allows one to extract additional and complementary information about the physical source of cosmic birefringence with respect to the isotropic case. We focus here on the case of an axion-like field χ, whose coupling with the electromagnetic sector induces such a phenomenon, by using an analytical and numerical approach (which involves a modification of the CLASS code). We find that the anisotropic component of cosmic birefringence exhibits a peculiar behavior: an increase of the axion mass implies an enhancement of the anisotropic amplitude, allowing to probe a wider range of masses with respect to the purely isotropic case. Moreover, we show that at large angular scales, the interplay between the reionization and recombination contributions to ACB is sensitive to the axion mass, so that at sufficiently low multipoles, for sufficiently light masses, the reionization contribution overtakes the recombination one, making the tomographic approach to cosmic birefringence a promising tool for investigating the properties of this axion-like field.

C−P−T fractionalization

Discrete spacetime symmetries of parity P or reflection R, and time-reversal T, act naively as $\mathbb{Z}_2$-involutions in the passive transformation on the spacetime coordinates; but together with a charge conjugation C, the total C-P-R-T symmetries have enriched active transformations on fields in representations of the spacetime-internal symmetry groups of quantum field theories (QFTs). In this work, we derive that these symmetries can be further fractionalized, especially in the presence of the fermion parity $(-1)^{\rm F}$. We elaborate on examples including relativistic Lorentz invariant QFTs (e.g., spin-1/2 Dirac or Majorana spinor fermion theories) and nonrelativistic quantum many-body systems (involving Majorana zero modes), and comment on applications to spin-1 Maxwell electromagnetism (QED) or interacting Yang-Mills (QCD) gauge theories. We discover various C-P-R-T-$(-1)^{\rm F}$ group structures, e.g., Dirac spinor is in a projective representation of $\mathbb{Z}_2^{\rm C}\times \mathbb{Z}_2^{\rm P} \times \mathbb{Z}_2^{\rm T}$ but in an (anti)linear representation of an order-16 nonabelian finite group, as the central product between an order-8 dihedral (generated by C and P) or quaternion group and an order-4 group generated by T with T$^2=(-1)^{\rm F}$. The general theme may be coined as C-P-T or C-R-T fractionalization.

Planck constraints on cross-correlations between anisotropic cosmic birefringence and CMB polarization

Cosmic Birefringence (CB) is the in-vacuo rotation of the linear polarization direction of photons during propagation, caused by parity-violating extensions of Maxwell electromagnetism. We build low resolution CB angle maps using Planck Legacy and NPIPE products and provide for the first time estimates of the cross-correlation spectra CL αE and CL αB between the CB and the CMB polarization fields. We also provide updated CB auto-correlation spectra CL αα as well as the cross-correlation CL αT with the CMB temperature field. We report constraints by defining the scale-invariant amplitudes AαX ≡ L(L + 1)CL αX /2π, where X = α, T, E, B, finding no evidence of CB. In particular, we find AαE = (-7.8 ± 5.6) nK deg and AαB = (0.3 ± 4.0) nK deg at 68% C.L..

On the linearity of the generalized Lorentz transformation

Lorentz transformations between inertial observers, along with Einstein's theory of special relativity, remedied discrepancies between Newtonian physics and Maxwell's electromagnetism caused by the use of the same time in all inertial frames. In view of the fundamental importance of the relativity between inertial observers, there have been several papers deriving generalized Lorentz transformations without using light. Proving that general transformations are linear in space and time can be done in several ways, most commonly relying on a four-dimensional Minkowski spacetime, but other approaches are possible. A method is presented here that establishes the linearity of the transformation by considering velocity transformations in the light of Einstein's first relativity postulate of 1905. Once linearity is obtained, the remainder is fairly straightforward and parallels results and methods found in the literature.

Cosmic birefrigence: cross-spectra and cross-bispectra with CMB anisotropies

Parity-violating extensions of Maxwell electromagnetism induce a rotation of the linear polarization plane of photons during propagation. This effect, known as cosmic birefringence, impacts on the Cosmic Microwave Background (CMB) observations producing a mixing of E and B polarization modes which is otherwise null in the standard scenario. Such an effect is naturally parametrized by a rotation angle which can be written as the sum of an isotropic component α 0 and an anisotropic one δα(n̂). In this paper we compute angular power spectra and bispectra involving δα and the CMB temperature and polarization maps. In particular, contrarily to what happens for the cross-spectra, we show that even in absence of primordial cross-correlations between the anisotropic birefringence angle and the CMB maps, there exist non-vanishing three-point correlation functions carrying signatures of parity-breaking physics. Furthermore, we find that such angular bispectra still survive in a regime of purely anisotropic cosmic birefringence, which corresponds to the conservative case of having α o = 0. These bispectra represent an additional observable aimed at studying cosmic birefringence and its parity-violating nature beyond power spectrum analyses. They provide also a way to perform consistency checks for specific models of cosmic birefringence. Moreover, we estimate that among all the possible birefringent bispectra,〈δαTB〉and〈δαEB〉are the ones which contain the largest signal-to-noise ratio. Once the cosmic birefringence signal is taken to be at the level of current constraints, we show that these bispectra are within reach of future CMB experiments, as LiteBIRD.

Generalized magneto-thermoelasticity of a layer based on the Lord–Shulman and Green–Lindsay theories

In this research, development and solution of the generalized magneto-thermoelastic response of a layer based on both Lord–Shulman and Green–Lindsay theories are reported. To this end, the Maxwell electromagnetism equations are reduced to one-dimensional space. The Lorentz force is applied to obtain the magnetic body force and extract the effect of the magnetic field effect on the equation of motion of the layer. The heat conduction equation is also established for the one-dimensional layer using both the Lord–Shulman and Green–Lindsay theories. The established equations are four in number in terms of displacement, temperature change, induced magnetic field and electric field. Equations are reformulated in a dimensionless presentation where the speed of waves is also changed. Using the generalized differential quadrature method, the established dimensionless equations are discreted and provided in a matrix representation. Next, using Newmark time marching scheme, equations are traced in time. At first results of this study are compared with the available data in the open literature. After that novel results are given for a layer. It is shown that under both of the mentioned theories, temperature propagates with finite speed where the speed of wave may be obtained using the relaxation times.

Trajectory Tracking Control of a Fast Tool Servo System Driven by Maxwell Electromagnetic Force

Trajectory Tracking Control of a Fast Tool Servo System Driven by Maxwell Electromagnetic Force

BLDC Motor Design and Application for Light Electric Vehicle

The popularity of electrical vehicles is increasing rapidly in recent years due to energy generation/consumption ratio, transportation costs, decrease in fossil fuel reserves with increasing population as well as the environmental damage caused by fossil fuels. Therefore, Brushless Direct Current (BLDC) Motor design was actualized in the present study for use in electrical vehicles expected to replace the transportation vehicles of today. Firstly, analytical design of the targeted motor was completed after which the Finite Elements Method was used for modelling. Ansys Maxwell Program is one of the package programs used in FEM. This study was carried out with Ansys Maxwell Electromagnetic Suite version 17.2 . The prototype motor was manufactured after reaching the desired results with Finite Elements Method and experimental studies commenced with the experiment setup prepared in the laboratory environment. Experimental results were compared with electromagnetic results. Finally, the prototype motor was mounted on the ElektroGOP vehicle and it was observed to work without problem at the expected performance during the test drives.

Second Gradient Electromagnetostatics: Electric Point Charge, Electrostatic and Magnetostatic Dipoles

In this paper, we study the theory of second gradient electromagnetostatics as the static version of second gradient electrodynamics. The theory of second gradient electrodynamics is a linear generalization of higher order of classical Maxwell electrodynamics whose Lagrangian is both Lorentz and U ( 1 ) -gauge invariant. Second gradient electromagnetostatics is a gradient field theory with up to second-order derivatives of the electromagnetic field strengths in the Lagrangian. Moreover, it possesses a weak nonlocality in space and gives a regularization based on higher-order partial differential equations. From the group theoretical point of view, in second gradient electromagnetostatics the (isotropic) constitutive relations involve an invariant scalar differential operator of fourth order in addition to scalar constitutive parameters. We investigate the classical static problems of an electric point charge, and electric and magnetic dipoles in the framework of second gradient electromagnetostatics, and we show that all the electromagnetic fields (potential, field strength, interaction energy, interaction force) are singularity-free, unlike the corresponding solutions in the classical Maxwell electromagnetism and in the Bopp–Podolsky theory. The theory of second gradient electromagnetostatics delivers a singularity-free electromagnetic field theory with weak spatial nonlocality.

Beyond Boltzmann-Gibbs-Shannon in Physics and Elsewhere.

The pillars of contemporary theoretical physics are classical mechanics, Maxwell electromagnetism, relativity, quantum mechanics, and Boltzmann–Gibbs (BG) statistical mechanics –including its connection with thermodynamics. The BG theory describes amazingly well the thermal equilibrium of a plethora of so-called simple systems. However, BG statistical mechanics and its basic additive entropy started, in recent decades, to exhibit failures or inadequacies in an increasing number of complex systems. The emergence of such intriguing features became apparent in quantum systems as well, such as black holes and other area-law-like scenarios for the von Neumann entropy. In a different arena, the efficiency of the Shannon entropy—as the BG functional is currently called in engineering and communication theory—started to be perceived as not necessarily optimal in the processing of images (e.g., medical ones) and time series (e.g., economic ones). Such is the case in the presence of generic long-range space correlations, long memory, sub-exponential sensitivity to the initial conditions (hence vanishing largest Lyapunov exponents), and similar features. Finally, we witnessed, during the last two decades, an explosion of asymptotically scale-free complex networks. This wide range of important systems eventually gave support, since 1988, to the generalization of the BG theory. Nonadditive entropies generalizing the BG one and their consequences have been introduced and intensively studied worldwide. The present review focuses on these concepts and their predictions, verifications, and applications in physics and elsewhere. Some selected examples (in quantum information, high- and low-energy physics, low-dimensional nonlinear dynamical systems, earthquakes, turbulence, long-range interacting systems, and scale-free networks) illustrate successful applications. The grounding thermodynamical framework is briefly described as well.

Electric Charge and Its Field as Deformed Space

The essence of electric charge has been a mystery. So far, no theory has been able to derive the attributes of electric charge, which are: bivalency, stability, quantization, equality of the absolute values of the bivalent charges, the electric field it creates and the radii of the bivalent charges. Our model of the electric charge and its field (this paper) enables us (in additional papers), for the first time, to derive simple equations for the radii and masses of the electron/positron muon/anti-muon and quarks/anti-quarks. These equations contain only the constants G, c, ℏ  and α (the fine structure constant). The calculated results based on these equations comply accurately with the experimental results. In this paper, which serves as a basis for the other papers, we define electric charge density, based on space density. This definition alone, without any phenomenology, yields the theory of Electrostatics. Electrostatics together with Lorentz Transformation is known to yield the entire Maxwell Electromagnetic theory.

Topological non-Hermitian origin of surface Maxwell waves

Maxwell electromagnetism, describing the wave properties of light, was formulated 150 years ago. More than 60 years ago it was shown that interfaces between optical media (including dielectrics, metals, negative-index materials) can support surface electromagnetic waves, which now play crucial roles in plasmonics, metamaterials, and nano-photonics. Here we show that surface Maxwell waves at interfaces between homogeneous isotropic media described by real permittivities and permeabilities have a topological origin explained by the bulk-boundary correspondence. Importantly, the topological classification is determined by the helicity operator, which is generically non-Hermitian even in lossless optical media. The corresponding topological invariant, which determines the number of surface modes, is a {Bbb Z}_4 number (or a pair of {Bbb Z}_2 numbers) describing the winding of the complex helicity spectrum across the interface. Our theory provides a new twist and insights for several areas of wave physics: Maxwell electromagnetism, topological quantum states, non-Hermitian wave physics, and metamaterials.

Electromagnetic Helicity in Complex Media.

Optical helicity density is usually discussed for monochromatic electromagnetic fields in free space. It plays an important role in the interaction with chiral molecules or nanoparticles. Here we introduce the optical helicity density in a dispersive isotropic medium. Our definition is consistent with biorthogonal Maxwell electromagnetism in optical media and the Brillouin energy density as well as with the recently introduced canonical momentum and spin of light in dispersive media. We consider a number of examples, including electromagnetic waves in dielectrics, negative-index materials, and metals, as well as interactions of light in a medium with chiral and magnetoelectric molecules.

Numerical simulation of induction heating thick-walled tubes

In the paper is shown the connection of two toolboxes in an Ansys Workbench solution for induction heating. In Ansys Workbench, Maxwell electromagnetism programs and Fluent have been linked. In Maxwell, a simulation of electromagnetic induction was performed, where data on the magnetic field distribution in the heated material was obtained and then transformed into the Fluent program in which the induction heating simulation was performed.

Knotted solutions, from electromagnetism to fluid dynamics

Knotted solutions to electromagnetism and fluid dynamics are investigated, based on relations we find between the two subjects. We can write fluid dynamics in electromagnetism language, but only on an initial surface, or for linear perturbations, and we use this map to find knotted fluid solutions, as well as new electromagnetic solutions. We find that knotted solutions of Maxwell electromagnetism are also solutions of more general nonlinear theories, like Born–Infeld, and including ones which contain quantum corrections from couplings with other modes, like Euler–Heisenberg and string theory DBI. Null configurations in electromagnetism can be described as a null pressureless fluid, and from this map we can find null fluid knotted solutions. A type of nonrelativistic reduction of the relativistic fluid equations is described, which allows us to find also solutions of the (nonrelativistic) Euler’s equations.