Solution synthesis of core-shell Co9S8@MoS2 catalysts

SSCI-VIDE+ECI2D+AHD:CGE:PAFInternational audienceCore-shell Co9S8@MoS2 unsupported catalysts have been prepared by a solution reaction in ethylene glycol. First, using a cobalt sulfide seed, amorphous core-shell CoS@MoSx (x = 3-4) was prepared. Then, after thermal treatment, 20-50 nm-sized particles were obtained, in which MoS2 was crystallized at the exterior of the Co9S8 core. The solids show high catalytic activity in hydrodesulphurization, with an exceptionally high thermal stability. Thus, the high catalytic activity was preserved even after thermal treatment at 750 degrees C. A symmetric synergy model has been proposed with the catalytic sites located at the interface between the cobalt sulfide crystallites and the stacks of MoS2 slabs

Non-Parametric Tomographic SAR Reconstruction via Improved Regularized MUSIC

Height estimation of scatterers in complex environments via the Tomographic Synthetic Aperture Radar (TomoSAR) technique is still a valuable research field. The parametric spectral estimation approach constitutes a powerful tool to identify the superimposed scatterers with different complex reflectivities, located at different heights in the same range–azimuth resolution cell. Unfortunately, this approach requires prior knowledge about the number of scatterers for each pixel, which is not possible in practical situations. In this paper, we propose a method that analyzes the scree plot, generated from the spectral decomposition of the multidimensional covariance matrix, in order to estimate automatically the number of scatterers for each resolution cell. In this context, a properly improved regularization step is included during the reconstruction process, transforming the parametric MUSIC estimator into a non-parametric method. The experimental results on two data sets covering high elevation towers, with different facade coating characteristics, acquired by the TerraSAR-X satellite highlighted the effectiveness of the proposed regularized MUSIC for the reconstruction of high man-made structures compared with classical approaches

Chemical and physical characteristics of dune sand filters after operation

International audienceWastewater flow through a sand filter causes variations in the physical and chemical properties of the filter media. The objective of this study was to investigate and characterize the physical and chemical properties of dune sand filters after a certain period of operation. Lab-scale studies were performed using four dune sand filter columns for treating wastewater. The column was split into ten layers; each of which was through physical and chemical analyses after a certain operational period. It was observed that 34%–51% of the organic matter in the column was found in the top layer. The flow of wastewater caused a deposition of limestone and fine particles onto the filter. There was a noticeably low pH in the upper layers of the columns due to the high amounts of organic matter. Lastly, the virgin sands were more saturated in salts than the used sand after operation. © 2018 Desalination Publications. All rights reserved

Formaldehyde removal by photocatalytic mortar mixed with TiO2.

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