Identification of particulate heavy metal pollution sources in urban river sediment using scanning electron microscopy coupled with energy dispersive spectrometer (SEM-EDS)

8 p.International audienceScanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) was used to develop a protocol for the identification of trace element carriers in the Seine River. Various Pb, Ni, Zn, V, Cr, and Cu bearing phases were identified on the sediment of the Seine River. Lead and nickel were found to be preferentially bound with iron sulfide particles. This phase is known to be a significant trace metal carrier in a reducing environment. Association of vanadium and calcium was identified which would be a product of road surface runoff. Zinc was also found associated with barite, possibly indicating an urban-related contamination source. Microscopic particle analysis shows to be a powerful tool in the characterization of their different sources and their eventual mobility in the environment

Trusted Software within Focal

International audienceThis paper describes the Integrated Development Environment Focal together with a brief proof of usability on the formal development of access control policies. Focal is an IDE providing powerful functional and object-oriented features that allow to formally express specification and to go step by step (in an incremental approach) to design and implement while proving that the implementation meets its specification or design requirements. These features are particularly well-suited to develop libraries for secure applications

Développement de logiciel critique en FoCalize (méthodologie et outils pour l'évaluation de conformité)

Tout semble montrer que la complexité des logiciels croit plus vite que notre capacité à démontrer leur bonne adéquation aux besoins requis et leur bon fonctionnement. Cette thèse repose sur l'expérience de l'auteur, en tant qu'évaluateur de systèmes critiques pilotés par du logiciel et tente de répondre aux besoins de support théorique et de formalisation des études de risque, afin de conforter les décisions de mise en exploitation. Le problème est posé dans le cadre de l'utilisation de l'atelier de développement FoCalize. Il permet l'écriture de spécifications sous la forme de formules du premier ordre puis le développement progressif du code, en utilisant héritage, paramétrisation et modularité. La thèse s'intéresse à deux aspects de la certification d'un logiciel critique développé à l'aide de l'atelier FoCalize. La conformité de l'outil aux exigences requises par les principales normes applicables dans le domaine de la Sûreté de Fonctionnement est étudiée. Pour cela, un cycle de développement système couvrant l'ensemble des phases de développement est proposé. Ce travail permet de montrer que l'outil FoCalize possède toutes les caractéristiques nécessaires à une certification. La thèse porte ensuite sur la réalisation d'analyses de risques sur un logiciel issu d'un développement en FoCalize. Une présentation des différentes méthodes appliquées pour l'évaluation d'un logiciel est effectuée. Puis, un outil de calcul de dépendances entre Entrées/Sorties vraies d'un composant est spécifié formellement en Coq et sa preuve de correction est fournie. Une implémentation d'un prototype a été réalisée et appliquée sur un régulateur de vitesse.PARIS-BIUSJ-Mathématiques rech (751052111) / SudocSudocFranceF

Development Life-cycle of Critical Software Under FoCaL

AbstractBefore their installation, critical systems must be assessed by an independent authority, who ensures that software components are really compliant with a set of requirements described in standards. Such standards describe the framework and the rules to be strictly followed along the development process. Moreover high levels of safety highly recommand the use of formal methods.In this paper, we examine how the FoCaL development environment can help to fulfil these requirements and to ease assessment. This tool aims to help all stages of critical software development, at least when formal methods are required (step-by-step specification and implementation, properties expressed by first-order formulae, proofs helped by automatic tool). Upon our experience as either software safety assessor or researchers in software engineering and formal methods, we propose a development life cycle adapted to the FoCaL specificity and compliant with independent assessment requirements, through a complete example. We show how features such as inheritance, late binding, redefinition, parametrisation, encapsulation and declarations/definitions, properties/theorems, whole development checked by an independent proof assistant and partially automatic documentation can be used to improve the global safety and the re-use of software components

Reactivity of cyclohexene using ordered mesoporous materials based on calcined CoFeAl hydrotalcite-supported CoMo catalysts

International audienc

Identification of particulate heavy metal pollution sources in urban river sediment using scanning electron microscopy coupled with energy dispersive spectrometer (SEM-EDS)

8 p.International audienceScanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) was used to develop a protocol for the identification of trace element carriers in the Seine River. Various Pb, Ni, Zn, V, Cr, and Cu bearing phases were identified on the sediment of the Seine River. Lead and nickel were found to be preferentially bound with iron sulfide particles. This phase is known to be a significant trace metal carrier in a reducing environment. Association of vanadium and calcium was identified which would be a product of road surface runoff. Zinc was also found associated with barite, possibly indicating an urban-related contamination source. Microscopic particle analysis shows to be a powerful tool in the characterization of their different sources and their eventual mobility in the environment

Inorganic hydroxide fluorides as solid catalysts for acylation of 2-methylfuran by acetic anhydride

International audienceSeveral inorganic hydroxide fluorides MFn−x(OH)x with M being either aluminum, iron, or magnesium were synthesized using a sol–gel method. These mesoporous fluoride materials exhibited very high specific surface areas (between 60 and 370 m2 g−1) depending on the synthesis parameters used (nature of the metal, HF/Al ratio, and thermal treatment). It is shown that their acidic properties can also be adjusted by tuning these parameters. Indeed, in the case of aluminum hydroxide fluorides, bi-acidic catalysts containing both Brønsted and Lewis acid sites were obtained, the amount of acid sites and the Lewis/Bronsted ratio (in the range of 1.9–7.6) being very dependent on the synthesis parameters. For example, the increase of the calcination temperature of aluminum hydroxide fluorides led to a decrease of both Lewis and Brønsted acid site, but also an increase of the Lewis/Bronsted ratio. The most acid fluoride exhibited 542 μmol g−1 of Lewis acid sites and 291 μmol g−1 of Brønsted acid sites.These inorganic hydroxide fluorides were successively used as catalysts for the solvent-free acylation of 2-methylfuran by acetic anhydride under mild conditions (50 °C, atmospheric pressure) yielding selectively 2-acetyl-5-methylfuran. The activity of fluoride can be related to the amount of both Lewis and Brønsted acid sites. In general the higher these values, the greater the activity in acylation. A reaction mechanism was proposed involving a bi-acidic site which could be a Lewis acid site (unsaturated aluminum) in the vicinity of a Brønsted acid site