Abstract: The present invention describes a method for measuring the concentrations of species present at one point of a separation unit functioning in simulated moving bed mode (SMB), using an immersing probe located at one point in the unit or on one of the streams entering or leaving said unit, and a thermocouple located in the vicinity of the immersing probe, in which a Raman spectrum obtained using a laser source functioning at a wavelength of 785 nm is utilized.

Abstract: The present invention describes a method for measuring the concentrations of species present at one point of a separation unit functioning in simulated moving bed mode (SMB), using an immersing probe located at one point in the unit or on one of the streams entering or leaving said unit, and a thermocouple located in the vicinity of the immersing probe, in which a Raman spectrum obtained using a laser source functioning at a wavelength of 785 nm is utilized. Application of the method to controlling and regulating a SMB xylenes separation unit.

Abstract: Reinforcing glass yarn, the composition of which comprises the following constituents, within the limits defined below, expressed in percentages by weight: SiO2 54.5 to 58% Al2O3 12 to 15.5% SiO2 + Al2O3 70 to 73% CaO 17 to 25% MgO 0 to 5% RO = CaO + MgO 21 to 28% R2O = Na2O + K2O + Li2O up to 2% TiO2 less than 1% Fe2O3 less than 0.5% B2O3 up to 3% F2 less than 1% and such that the ratio R1=Al2O3/CaO is less than 0.7, and when SiO2 is greater than 57% the amount of boron oxide B2O3 is greater than 2%.

Abstract: An inelastic diffusion spectrometric imaging apparatus includes an illuminating and energising system including a confocal first aperture and a second confocal aperture combined with the first. A first deflector assembly scanning for scanning a sample and a second deflector assembly sychronised with the first, are placed respectively downstream and upstream of the second confocal aperture and a spectrometer. The input aperture of the spectrometer merges with the second confocal aperture.

Abstract: In an optical fittering device comprising at least two fitters, the first filter (EF1) is tilted by an angle of incidence whose value is adjusted to bring the cut-off limit of the first filter (EF1) closer to one of the sides of the line of the illumination beam (FLA), which reduces the optical density of the first filter, while the association in series of the first (EF1) and second (EF2) filters enables to obtain a high-pass filtering whose global density corresponds to the sum of the densities of the first and second filters and whose cut-off limit is lower than that obtained by a single filter tilted to its optimum angle. A third filter (EF3) mounted in parallel with respect to the first and second filters (EF1 and EF2) enables to obtain, at the level of the common collection path (TCC), a band eliminating filtering whose cut-off limits are positioned on either side of the illumination line with a view to an optimum analysis of the low frequency lines.

Abstract: The method concerns preparing a contact material constituted by silver and tin oxide.According to the invention the method comprises the following steps:preparing an aqueous solution containing dissolved silver nitrate and tin oxide particles in suspension, with the size of said particles measured in terms of specific surface area using the BET method lying between about 2 m.sup.2 /g and 6 m.sup.2 /g;causing silver nitrate to precipitate in silver hydroxide by rapidly adding a strong base and stirring, with silver hydroxide being unstable and transforming progressively into silver oxide;eliminating the ions from the solution and then the water in order to obtain a dry product; andheating the dry product to a temperature of about 200.degree. C. to 500.degree. C. in order to reduce the silver oxide to metallic silver.The invention is applicable to manufacturing electrical contacts for opening and closing in electromechanical apparatuses.