Influence of the continuous casting process of TIN-ZINC-LEAD bronze on the wear of the graphite crystallizer

The research conducted in this paper concerns the influence of the continuous casting process of tin-zinc-lead bronze on the wear of the graphite crystallizer. Observations and testing of the external surface of the cast rods indicate their good quality, without casting defects. No excessive surface degradation was observed on the inner surface of the crystallizers after casting. It was assessed that the surface quality of the crystallizer would be acceptable for further use, despite stuck residue, mainly in the crystallization zone

Influence of the continuous casting process of TIN-ZINC-LEAD bronze on the wear of the graphite crystallizer

The research conducted in this paper concerns the influence of the continuous casting process of tin-zinc-lead bronze on the wear of the graphite crystallizer. Observations and testing of the external surface of the cast rods indicate their good quality, without casting defects. No excessive surface degradation was observed on the inner surface of the crystallizers after casting. It was assessed that the surface quality of the crystallizer would be acceptable for further use, despite stuck residue, mainly in the crystallization zone

Second-harmonic generation from coupled plasmon modes in a single dimer of gold nanospheres

We show that a dimer made of two gold nanospheres exhibits a remarkable efficiency for second-harmonic generation under femtosecond optical excitation. The detectable nonlinear emission for the given particle size and excitation wavelength arises when the two nanoparticles are as close as possible to contact, as in situ controlled and measured using the tip of an atomic force microscope. The excitation wavelength dependence of the second-harmonic signal supports a coupled plasmon resonance origin with radiation from the dimer gap. This nanometer-size light source might be used for high-resolution near-field optical microscopy.Comment: 6 pages, 5 figure

Wide frequency range analysis of the electromagnetic emissions of electrical machine for diagnosis

The paper presents the possibilities to evaluate the health of an electrical machine by analyzing its electromagnetic emissions. Different piece of information can be detected according to the frequency range. First of all, a monitoring system sensitive to the degradation of the turn-to-turn insulation quality of the stator winding is presented; it is based on high frequency electromagnetic emissions. The second part of the paper is based on the medium and low frequency emission analysis. It explains how to detect turn-to-turn short circuits in stator windings or in the excitation coils of synchronous machines

Influence of a charging current with a sinusoidal perturbation on the performance of a lead-acid battery

International audienc

Analytical computation of an AC machine external magnetic field

This paper presents an analytical approach to estimate the magnitude of a flux density component at a point located outside an AC machine. The study uses the concept of attenuation coefficients which are determined using several hypotheses. The developments consider the different media according to they are flowed by eddy currents or not. Then, the calculations are performed in each medium

Wind turbines using self-excited three-phase induction generators: an innovative solution for voltage-frequency control

A considerable number of communities throughout the world, most of them isolated, need hybrid energy solutions either for rural electrification or for the reduction of diesel use. Despite several research projects and demonstrations which have been conducted in recent years, wind-diesel technology remains complex and much too costly. Induction generators are the most robust and common for wind energy systems but this option is a serious challenge for electrical regulation. When a wind turbine is used in an off-grid configuration, either continuously or intermittently, precise and robust regulation is difficult to attain. The voltage parameter regulation option, as was experienced at several remote sites (on islands and in the arctic for example), is a safe, reliable and relatively simple technology, but does not optimize the wave quality and creates instabilities. These difficulties are due to the fact that no theory is available to describe the system, due to the inverse nature of the problem. In order to address and solve the problem of the unstable operation of this wind turbine generator, an innovative approach is described, based on a different induction generator single phase equivalent circuit