The NEPTUNE project constitutes the thermal-hydraulic part of the long-term Electricite de France and Commissariat a l’Energie Atomique joint research and development program for the next generatio...

NEPTUNE : A new software platform for advanced nuclear thermal hydraulics

Mining activities generate spoils and efflu- ents with extremely high metal concentrations of heavy metals that might have adverse effects on ecosystems and human health. Therefore, information on soil and plant metal concentrations is needed to assess the severity of the pollution and develop a strategy for soil reclamation such as phytoremedia- tion. Here, we studied soils and vegetation in three heavily contaminated sites with potential toxic metals and metalloids (Zn, Pb, Cd, As, TI) in the mining district of Les Malines in the Languedoc region (southern France). Extremely high concentrations were found at different places such as the Les Avinieres tailing basins (up to 160,000 mg kg -1 Zn, 90,000 mg kg -1 Pb, 9,700 mg kg -1 of As and 245 mg kg -1 of Tl) near a former furnace. Metal contamination extended several kilometres away from the mine sites probably because of the transport of toxic mining residues by wind and water. Spontaneous vegetation growing on the three mine sites was highly diversified and included 116 plant species. The vegetation cover consisted of species also found in non-contaminated soils, some of which have been shown to be metal- tolerant ecotypes (Festuca arvernensis, Koeleria vallesiana and Armeria arenaria) and several Zn, Cd and Tl hyperaccumulators such as Anthyllis vulneraria, Thlaspi caerulescens, Iberis intermedia and Silene latifolia. This latter species was highlighted as a new thallium hyperaccumulator, accumulating nearly 1,500 mg kg -1 . These species represent a patrimonial interest for their potential use for the phytoremediation of toxic metal-polluted areas.

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Heavy Metal Concentration Survey in Soils and Plants of the Les Malines Mining District (Southern France): Implications for Soil Restoration

A Godunov-type method for the shallow water equations with discontinuous topography in the resonant regime

https://hal.archives-ouvertes.fr/hal-00517375/document

A Godunov-type method for the seven-equation model of compressible two-phase flow

A new treatment of capillarity to improve the stability of IMPES two-phase flow formulation

This paper is concerned with the numerical approximation of the solutions of a two-fluid two-pressure model used in the modelling of two-phase flows. We present a relaxation strategy for easily dealing with both the nonlinearities associated with the pressure laws and the nonconservative terms that are inherently present in the set of convective equations and that couple the two phases. In particular, the proposed approximate Riemann solver is given by explicit formulas, preserves the natural phase space, and exactly captures the coupling waves between the two phases. Numerical evidences are given to corroborate the validity of our approach.

/pdf/relaxation-and-numerical-approximation-of-a-two-fluid-two-3i715gvyzw.pdf

Relaxation and numerical approximation of a two-fluid two-pressure diphasic model

We consider the numerical coupling at a fixed spatial interface of two homogeneous models used for describing non isothermal compressible two phase flows. More precisely, we concentrate on the numerical coupling of the homogeneous equilibrium model and the homogeneous relaxation model in the context of finite volume methods. Three methods of coupling are presented. They are based on one of the following requirements: continuity of the conservative variable through the coupling interface, continuity of the primitive variable and global conservation of mass, momentum and energy. At the end, several numerical experiments are presented in order to illustrate the ability of each method to provide results in agreement with their principle of construction.

https://hal.archives-ouvertes.fr/hal-01117451/document

The coupling of homogeneous models for two-phase flows

A method to couple HEM and HRM two-phase flow models

This paper deals with the non-conservative coupling of two one-dimensional barotropic Euler systems at an interface at x = 0. The closure pressure laws differ in the domains x > 0, and a Dirac source term concentrated at x = 0 models singular pressure losses. We propose two numerical methods. The first one relies on ghost state reconstructions at the interface while the second is based on a suitable relaxation framework. Both methods satisfy a well-balanced property for stationary solutions. In addition, the second method preserves mass conservation and exactly restores the prescribed singular pressure drops for both unsteady and steady solutions.

/pdf/interface-model-coupling-via-prescribed-local-flux-balance-3wgskughz0.pdf

Annalisa Ambroso

Papers

A Godunov-type method for the seven-equation model of compressible two-phase flow

Relaxation and numerical approximation of a two-fluid two-pressure diphasic model

The coupling of homogeneous models for two-phase flows

A method to couple HEM and HRM two-phase flow models

Interface model coupling via prescribed local flux balance