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Epitaxial realignment of polycrystalline Si films was analyzed in terms of structural and kinetic characteristics. The results showed that the realignment mode and the kinetic activity of the process was connected to the microcrystalline structure of the layers, to the morphology of the film and to the presence of As atoms. In addition, the kinetics of the realignment modes were observed to be thermally activated.

The purpose of this research is to develop a direct spectrometric approach to monitor soils and waters, at a lower cost than the widely used chromatographic techniques; a spectrometric approach that is effective, reliable, fast, easy to implement, and without any use of organic solvents whose utilization is subject to law limitation. It could be suitable at least as an alert method in case of massive contamination. Here, we present for the first time a catalog of excitation-emission and total synchronous fluorescence maps that may be considered as fingerprints of a series of homologated pesticides, in large use in Morocco, aiming at a direct detection of their remains in agricultural soils and neighboring waters. After a large survey among farmers, agricultural workers and product distributors in two important agricultural regions of Morocco (Doukkala-Abda and Sebou basin), 48 commercial pesticides, which are fluorescent, were chosen. A multi-component spectral database of these targeted commercial pesticides was elaborated. For each pesticide, dissolved in water at the lowest concentration giving a no-noise fluorescence spectrum, the total excitation-emission matrix (TEEM), the total synchronous fluorescence matrix (TSFM) in addition to synchronous fluorescence spectra (SFS) at those offsets giving the highest fluorescence intensity were recorded. To test this preliminary multi-component database, two real soil samples, collected at a wheat field and at a vine field in the region of Doukkala, were analyzed. Remains of the commercial Pirimor (Carbamate) and Atlantis (Sulfonylurea) were identified by comparison of the recorded TEEM, TSFM, and SFS to those of the preliminary catalog at one hand, and on the basis of the results of a field pre-survey. The developed approach seems satisfactory, and the fluorimetric fingerprint database is under extension to a higher number of fluorescent pesticides in common use among the Moroccan agricultural regions. [ABSTRACT FROM AUTHOR]

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In this work, we were interested in a preliminary evaluation of air quality in the town of Meknes, in particular, the measurement of sulphur dioxide (SO2), ozone (O3) and the particulate matter in suspension (PM-10) whose particles have a diameter lower than 10 μm, with separation of the fractions according to the size: fine fractions (diameter lower or equalizes with 2.5 μg/m3) and coarse fractions (diameter between 2.5 μg/m3 and 10 μg/m3). The samples were collected one day in (July, October and November 2005) in several sites (urban, suburban, proximity,...). The mesures of the gaseous pollutants (SO2 and O3) were realized on the site every 15 min. by automatic analyzers (AF21M and O341M). Whereas, PM-10 were collected respectively by Dichotomous and the Gent samplers. The chemical and mineral composition of the PM-10 was determined by various techniques of physicochemical analyses: Atomic Absorption Spectrometer (SAA), X-ray Fluorescence in Total Reflection (TXRF), Scanning Electron Microscope coupled with Energy Dispersion Spectrometer (SEMEDS) and X-Rays Diffraction (XRD). [ABSTRACT FROM AUTHOR]

Investigates the realignment of arsenic doped polycrystalline silicon films by double step annealing. Movement of the interface to the surface; Lateral growth of columnar epitaxial islands; Relation of the different regrowth modes to the morphology of interfacial oxide layer.

Investigates the epitaxial realignment of polycrystalline silicon (Si) films on the crystalline Si substrates. Variation in the contact area dimensions; Use of rectangular width and length strips; Growth kinetics in the small width geometry.

The work is focusing on air pollution impacts on historical limestone buildings located in urban areas in Morocco. Black crusts sampled on the façades of two ancient limestone monuments, dating back to the 12th and 20th centuries edified in the cities of Salé and Casablanca, have been analyzed by means of ATR-FTIR and synchronous fluorescence spectroscopies. Infrared analyses revealed degradation products, mainly gypsum due to calcite sulphation under wetness and SO 2 rich oil fired soot, and oxalates due to ancient biological weathering. Synchronous fluorescence permitted the identification of the most hazardous PAHs along with other non-identified fluorescent organics; this technique appeared efficient and suitable for the analysis of fluorescent pollutants entrapped in black crusts. Such results keeping track of air pollution causing disfigurement of architectural heritage must alarm both cultural heritage and environmental decision makers., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The seasonal and spatial variations of particulate matter (PM2.5-10 and PM2.5) and its chemical composition have been studied over a one-year period in Kenitra city (2007-2008). The samples were collected using Gent stacked filters and dichotomous samplers in two size fractions: below 2.5 μm (fine) and 2.5 to 10 μm (coarse). The chemical compositions of the collected filters were evaluated by using Total X-ray Fluorescence and Atomic Absorption Spectroscopy. The influence of atmospheric transport scenarios on the levels of PM was elaborated by means of air mass back-trajectories, using the HYSPLIT™ model. This study allowed identifying four main transport patterns: short local flows over the Kenitra region, Northwesterly flows over the Atlantic Ocean, Northerly flows, and Southern flows. The highest PM2.5-10 concentrations were observed in the summer and the lowest in the winter. However, no significant seasonal variations were discerned for PM2.5 particles. The enrichment factor and risk assessment code were calculated to distinguish between anthropogenic influences and the natural background levels and assess the environmental risks of metals in PM2.5-10 and PM2.5 particles. A comparison of PM and metal concentrations in Kenitra city and other African cities (reported in the literature) revealed that that the values obtained in Kenitra city are significantly higher than those recorded for the other African cities (that are the subject of the comparison).