Review and Microphysics of the maximum electricity atmospheric activity in the Word: the Catatumbo Lightning (Venezuela)

A review and phenomenology on the greatest lightning hotspots in the world, known as the Catatumbo Lightning, located southeast of Lake Maracaibo (Venezuela), is presented. A microphysical model is presented to explain the charging process through electrical displacement within the cells of the cloud, incorporating the role of the self-polarization of ice and methane molecules as pyroelectric aerosol, which accounts for the phenomenology and is consistent with the electrification in thunderstorm. It is concluded that the pyroelectric model allows to explain the phenomenology of the rapid discharges of the flashes in the Catatumbo lightning and could be applied in outer planetary lightning.

CUBIC SILICON CARBIDE ON SILICON

A basic technology for cubic silicon carbide (3C-SiC) formation on silicon (Si) plates in high-frequency (HF and HFI) and very-high-frequency (microwave) discharges at low pressure has been developed. It is found that 3C-SiC layers formation on Si should be multiple staged, but integrated, i.e. sequential change of stages should be performed without working chamber deevacuating and accompanied only by changing modes, gaseous media and applying electrical displacement. The following technological mixtures have been proposed: SiF4 + CF4 + Ar; SiF4 + CH4 + Ar.

Evolution of the Electrical Displacement and Energy Dissipation of Lead Zirconate-Titanate Ceramics under Cyclical Load

In this paper, the electromechanical behavior of lead zirconate-titanate ceramics (P51) has been characterized and modeled. The variation of the energy dissipation and peak electrical displacement of the P51 ceramic has been investigated in details. The total strain of P51 under cyclical loading consists of elastic deformation (εije), immediate ferroelectric domain switching deformation (εijd), and time-dependent deformation (εijc). Thus, an expression for the energy dissipation of P51 can be theoretically derived. In addition, a practical method for calculating the dissipated energy has been proposed by integrating the curve of a hysteresis loop. The experimental results show that the peak electrical displacement and dissipated energy both decrease monotonously with the increase of the number of cycles. Furthermore, ferroelectric 90° domain switching was observed by X-ray diffraction (XRD) and the percentage of domain switching has been calculated by the variation of the peak intensity ratio of (002) to (200) at about 45 degrees. Then, grain debonding, crack, and crush were found around voids inside the specimen by using scanning electron microscope (SEM). It is indicated that switching of more capable-switch domains stimulates larger dissipated energy and a bigger peak electrical displacement at the initial cyclic loading. Finally, an exponential functional model has been proposed to simulate the peak evolution of electrical displacement based on the energy dissipation of P51 ceramics under cyclical load.

Analysing the Impact of Electrical Displacement and Leakage Currents in Transformer Insulation on Voltage Measurement Accuracy

The article examines the methods of calculating capacitive currents in a measuring transformer based on a resistive voltage divider. The developed methods may be used to optimize the design of resistive dividers.

Frictional Indentation of Anisotropic Magneto-Electro-Elastic Materials by a Rigid Indenter

An exact analysis on frictional contact between a rigid punch and anisotropic magneto-electro-elastic materials is performed, within the framework of the fully coupled theory. The indenter moves relative to magneto-electro-elastic materials, and Coulomb friction law is used. The mixed boundary value problem is reduced to singular integral equations of the second kind with analytical solution presented. For a triangular or semiparabolic indenter, explicit expression for surface physical in-plane stress, electrical displacement and magnetic induction are obtained. Influences of the friction coefficient and the volume fraction on contact behaviors are detailed under the prescribed contact loading conditions. Under either a triangular or semiparabolic indenter, the surface in-plane stress, electric displacement and magnetic induction are discontinuous and unbounded around the leading edge, and such a serious near-edge response can be relieved through adjusting the values of the friction coefficient or the volume fraction.

Results and limits in the 1-D analytical modeling for the asymmetric DG SOI MOSFET

This paper presents the results and the limits of 1-D analytical modeling of electrostatic potential in the low-doped p type silicon body of the asymmetric n-channel DG SOI MOSFET, where the contribution to the asymmetry comes only from p- and n-type doping of polysilicon used as the gate electrodes. Solving Poisson's equation with boundary conditions based on the continuity of normal electrical displacement at interfaces and the presence of a minimum electrostatic potential by using the Matlab code we have obtained a minimum potential with a slow variation in the central zone of silicon with the value pinned around 0.46 V, where the applied VGS voltage varies from 0.45 V to 0.95 V. The paper states clearly the validity domain of the analytical solution and the important effect of the localization of the minimum electrostatic potential value on the potential variation at interfaces as a function of the applied VGS voltage.

Some New Three-Dimensional Green's Functions in Antisotropic Piezoelectric Bimaterials

In this paper, we derive three-dimensional Green’s functions of point-force/pointcharge in anisotropic and piezoelectric bimaterials for six different interface models. Mechanically, the six interface models are either in perfect or smooth contact along the interface; electronically, they can be closed, open interface, or with continuous electrical potential and normal electrical displacement component along the interface. By introducing certain modified bimaterial Stroh matrices, along with the extended Stroh formalism and the Mindlin’s superposition method, the bimaterial Green’s functions for the six interface conditions are expressed in terms of a concise and mathematically similar uniform form. That is, the physical-domain bimaterial Green’s functions can all be expressed as a sum of a homogeneous full-space Green’s function in an explicit form and a complementary part in terms of simple line-integrals over [0, π] suitable for standard numerical integration. Furthermore, utilizing a direct connection between the 2D and 3D Stroh matrices observed in this paper, the corresponding 2D bimaterial Green’s functions are also derived, in exact-closed form, for the six interface conditions. Based on the bimaterial Green’s functions, the effects of different interface conditions on the mechanical and electrical fields are discussed. It is noted that only the complementary part of the solution contributes to the differences of the mechanical and electrical fields arising from different interface conditions. Also, numerical examples are presented for the Green’s functions in the bimaterials made of two half-spaces with two typical piezoelectric materials, quartz and ceramic. Certain new features are observed which could be of great interest to the design of piezoelectric composites and to the numerical modeling of strained quantum devices using the boundary element method.

XX. Experiments on contact electricity between non-conductors

It was observed that when a plate of copper was lifted from a plate of glass the copper was electrified, and also that when a plate of glass was lifted from a plate of wax the glass was electrified, care being taken to have as little friction as possible; it was afterwards found that the former experiment had already been made by Fechner (see Wiedemann’s ‘Gal-vanismus, page 21), who also tried lifting copper from sulphur and got the same effect; although the plates were lifted as carefully as possible, yet- it was not certain that friction had been entirely got rid of, so the following experiments were made to show that there is an electrical displacement when two non-conductors or a conductor and a non-conductor are put in contact without friction. The arrangement used was as follows:— Glass rods, AB, CD, EF, GH, were fixed in a wooden frame ACGE; round these rods silk threads, BF, DH, were wound; an aluminium needle carrying a mirror, M, was hung by a silk thread from a brass rod, T, fastened in the wooden frame; a wire from the needle dipped into a glass vessel, N, containing sulphuric acid; a small magnet was fastened to the back of the mirror, and a glass case wTas placed over the whole; outside the glass case were magnets, by means of which the position of the needle was regulated; a wire also from the outside dipped into the vessel N, and was used to charge the needle with electricity; positive electricity was got from an ordinary electrophorus, negative from an electrophorus in which the resin was replaced by a plate of glass which was excited by silk. If wax and glass were the substances experimented on; a cake, OQRP, was made, one half of which, OSQ, was glass, the other half, RPS, being wax; the junction of the wax and glass was parallel to OQ, the wax sticking fast to the glass: this cake was then placed on the silk threads under the needle, and it was found possible to bring the needle into such a position that when it was charged with positive electricity it was deflected from the glass part of the cake, when charged with negative it was attracted towards it. In order to get rid of any electricity which might have got on the cake in the making, the cake was made the day before it was placed on the threads, and the experiment was made at least a day, sometimes a week, after putting the cake on the threads; pieces of glass and sulphur which had been treated in as nearly as possible the same way as those of which the cakes were made were taken and placed separately on the threads, but no electricity could be detected on them.