Search results for "POLARIZATION"
showing 10 items of 1884 documents
Real time polarization imaging of weld pool surface
2015
The search for an efficient on-line monitoring system focused on the real-time analysis of arc welding quality is an active area of research. The topography and the superficial temperature field of the weld pool can provide important information which can be used to regulate the welding parameters for depositing consistent welds. One difficulty relies on accessing this information despite the bright dazzling welding arc. In the present work, Stokes polarimetry and associated shape-from-polarization methods are applied for the analysis of the weld pool through its 810 nm-wavelength infrared emissions. The obtained information can provide a better understanding of the process, such as the usa…
Manufacturing and testing of a metal supported Ni-YSZ/YSZ/La2NiO4 IT-SOFC synthesized by physical surface deposition processes
2017
International audience; The manufacture of the last generation metal supported IT-SOFC complete cell by dry surface deposition pro-cesses is really challenging. Atmospheric Plasma Spraying (APS) and Reactive Magnetron Sputtering (RMS) processes are respectively adapted to deposit Ni-YSZ anode and YSZ electrolyte layers. RMS is also used to coat a thin and dense La2NiO4 (LNO) cathode layer. In this work, we have realized a complete cell on metallic support (ITM) produced by PLANSEE SE. The innovative LNO cathode layer was compared with screen-printed LNO layers, with and without RMS bonding layer. Electrochemical and Voltammetry tests were performed on these samples. It reveals lower perform…
Corrosion resistance of the FeAlC permanent magnet alloy
1998
Abstract The correlation between corrosion behaviour rate of hard magnetic FeAlC alloys and their microstructure and phase composition is presented. Potentiokinetic polarization curves of the tested material in acid (pH = 1 and 2) and neutral (pH = 7) sulphate solutions have been measured. For open-circuit condition, kinetic curves of etching of the samples in 0.5 M H2SO4 have been determined. The resistance of the tested magnets against atmospheric corrosion has been evaluated using a salt-spray test. The atmospheric corrosion rate is 1.5–2 times slower than that found for Nd-Fe-B type magnets. The FeAlC alloys show good corrosion resistance in neutral environments and corrode at rates…
Corrosion protection of Nd–Fe–B type permanent magnets by zinc phosphate surface conversion coatings
2001
Abstract The use of protective zinc phosphate top coatings to protect Nd–Fe–B type permanent magnets against corrosion is discussed. The progress of the phosphatisation process has been tested by simultaneous measurement of pH near surface, corrosion potential, substrate mass loss and phosphate coating mass gain. The corrosion behaviour of the magnet in phosphate solution was analyzed by the anodic polarization technique and the general resistance of the magnet to corrosion was evaluated by the Akimov drop test. It is shown that immersion of the magnet in the acidified (pH=2) phosphating solution containing Zn(II), nitrate and fluoride ions resulted in the formation of well adhered, thin an…
Non-equilibrium melting of colloidal crystals in confinement
2009
International audience; We report on a novel and flexible experiment to investigate the non-equilibrium melting behaviour of model crystals made from charged colloidal spheres. In a slit geometry polycrystalline material formed in a low salt region is driven by hydrostatic pressure up an evolving gradient in salt concentration and melts at large salt concentration. Depending on particle and initial salt concentration, driving velocity and the local salt concentration complex morphologic evolution is observed. Crystal-melt interface positions and the melting velocity are obtained quantitatively from time resolved Bragg- and polarization microscopic measurements. A simple theoretical model pr…
Effect of microstructure and chemical composition on localized corrosion resistance of a AISI 304L stainless steel after nanopulsed-laser surface mel…
2015
Abstract Changes induced in the surface properties of AISI 304L stainless steel when it is treated with a nanopulsed ytterbium-doped fiber laser were investigated to determine the microscale distribution of its physico-chemical properties. A Gaussian energy distribution was created with a radius of 71 μm (1/e2) at the focal point. Local investigations were carried out using transmission electron microscopy to consider the effect of overlapping individual laser impacts. The results obtained reveal that laser surface melting leads to changes in the crystallographic structure of the steel through the formation of a δ-ferritic phase. It also results in the creation of an oxide layer that increa…
Corrosion Behaviour of Ti6Al4V and TiMo10Zr4 Alloys in the Ringer’s Solution: Effect of pH and Plastic Strain
2015
The corrosion behaviour of titanium alloys is not well understood – especially the role of the microstructure and plastic strain. In this paper, the influence of the microstructure and plastic strain on the corrosion resistance of TiMo10Zr4 and Ti6Al4V alloys was studied in the Ringer’s solution at 37 °C. Measurements were performed for different pH values and in aerated and de-aerated solutions using potentiodynamic polarization techniques. Results obtained on the two alloys were compared. It was shown that in the absence of plastic strain TiMo10Zr4 shows better corrosion resistance than Ti6Al4V (especially for pH = 8). By contrast, the current density in the passive range measured after 8…
In-fiber time-resolved acousto-optics
2014
Time-resolved in-fiber acousto-optics permit the measurement of sub-ppm perturbations of the modal dispersion curves along sections of fiber exceeding 1 m long, with a spatial resolution in the order of few cm.
Suppression of pulse pedestal using nonlinear optical loop mirrors in grating-compensated dispersion-managed fiber transmission systems
2006
Pulse pedestal suppression by nonlinear optical loop mirrors is utilized to reduce the intersymbol interference caused by the group delay ripples of a real grating profile in dispersion-managed communication systems compensated by chirped fiber gratings.
Tuning of an Optical Dimer Nanoantenna by Electrically Controlling Its Load Impedance
2009
International audience; Optical antennas are elementary units used to direct optical radiation to the nanoscale. Here we demonstrate an active control over individual antenna performances by an external electrical trigger. We find that by an in-plane command of an anisotropic load medium, the electromagnetic interaction between individual elements constituting an optical antenna can be controlled, resulting in a strong polarization and tuning response. An active command of the antenna is a prerequisite for directing light wave through the utilization of such a device.