A coupled discrete element - lattice Boltzmann method to investigate internal erosion in soil

International audienceIn this paper, we present a coupled Discrete Element (DE) and Lattice Boltzmann (LB) method to model fluid-solid interactions. This method is applied to study and model a two-dimensional piping erosion through a set-up inspired by the Hole Erosion Test (HET). In this work, we mainly focus on grain detachments under hydraulic loading. Simulation results show that the erosion law classically used in such experiments, can be retrieved with our model. It illustrates that such coupled systems can be investigated with the LB-DE approach developed in this work. This approach is a promising tool which is well designed to perform such investigations at the grain scal

Les sciences de la Terre au service des sites et sols pollués. Etat de l'Art. Earth Sciences in contaminated soil's service. State of the art.

International audienceLes activités industrielles sont dans une large mesure à l'origine des sites et sols pollués. Ces derniers relèvent soit de pollutions chroniques souvent anciennes (fuites, rejets, décharges, etc.) soit de pollutions accidentelles. Les conséquences parfois graves engendrées par ces sites ont motivé les efforts de remédiation menés depuis quelques années. A l'exception des études toxicologiques, les principaux thèmes de la problématique sont présentés dans cet article. Une première partie est consacrée aux travaux d'investigation et de caractérisation. Dans ce cadre, les principales familles de polluants sont présentées ct les relations entre les contaminanls et les constituants des sols sont décrites. Dans la seconde partie, les techniques de traitement sont inventoriées et classées selon leurs principes ct leurs résultats. En conclusion, la problématique est étendue à celle des sédiments de dragage de port et de canaux

A guide and a toolbox for public involvement in the assessment and the management of contaminated sites

International audiencePublic participation is increasingly considered as a plain part of the assessment and the management of a contaminated site. It is also perceived as a difficult and sometimes risky challenge. In Europe, to our knowledge, beside académie virtual experiments on "test groups", feedback and recommendations on the subject are scarce and dispersed. Following own expériences on real cases, INERiS and IRSN, in collaboration with the Cire Ile de France, hâve developed for ADEME a guide and a toolbox for organising public involvement in the assessment and the management of contaminated sites. The guide and the toolbox are intended for ail actors dealing with a contaminated site: public authorities, site owners, consultants, and représentatives of the public (organisations, elected représentatives, ...). They are available to ail on a dedicated website (www.comrisk.com). This article présents and discusses the outlines and the rationale of the guide and its related tools

COMRISK : Un guide et une boîte à outils pour l'implication des populations dans l'évaluation et la gestion d'un site ou sol pollué

National audienceLes populations sont de plus en plus considérées comme parties intégrantes de l'évaluation et de la gestion des risques liés aux sites pollués. Mais leur implication est également reconnue comme un exercice difficile, mal maîtrisé, voire périlleux. De nombreux cas de relations agitées, conflictuelles, entre gestionnaires et riverains, sont rapportés. Mais des exemples de réussites apparaissent également. L'INERIS et l'IRSN, en collaboration avec la Cire Ile de France, ont développé pour l'ADEME un guide et une boîte à outils pour l'implication des populations dans l'évaluation et la gestion d'un site ou sol pollué. Le guide et la boîte à outils s'adressent à tous les acteurs des sites et sols pollués : maîtres d'ouvrage avec leurs bureaux d'études et conseils, administrations, et tout autant populations (associations, particuliers, élus,...). En effet, ils sont construits dans l'optique que les différents intervenants, par delà les différences de points de vue, travaillent ensemble à la recherche de la meilleure solution. Il est dès lors naturel qu'ils puissent disposer des mêmes outils méthodologiques, accessibles à tous (www.comrisk.fr). Le guide est organisé en fiches de préconisations opérationnelles, autonomes et illustrées d'exemples et de contre-exemples sur cas réels. Il propose au préalable une discussion synthétique des fondements des préconisations

Hamstring graft incorporation according to the length of the graft inside tunnels

BACKGROUND: Anterior cruciate ligament (ACL) reconstruction with a quadrupled semitendinosus (ST4) graft is an evolution of the standard technique with 2 hamstring tendons (semitendinosus + gracilis [STG]). However, there is no published comparison of how well these 2 types of hamstring grafts are incorporated into the bone tunnels. Because the ST4 graft is shorter, there is less graft material inside the tunnels. PURPOSE: To use magnetic resonance imaging (MRI) to compare graft incorporation in the tibial bone tunnels 1 year after ACL reconstruction with either an STG graft or ST4 graft. STUDY DESIGN: Cohort study. METHODS: Sixty-two patients who underwent ACL reconstruction were enrolled prospectively: 31 with an ST4 graft and 31 with an STG graft. The same surgical technique, fixation method, and postoperative protocol were used in both groups. Graft incorporation and ligamentization were evaluated with MRI after 1 year of follow-up. The following parameters were evaluated: signal-to-noise quotient (SNQ), tibial tunnel enlargement, signal intensity at the bone-graft interface, and graft signal according to the Howell scale. The number of participants needed to show that the mean SNQ did not differ between the 2 techniques was 31 in each group (with a 1-sided alpha of 2.5% and a 1-sided beta of 10.0%). The Student t test was used to compare the distribution of continuous secondary endpoints. RESULTS: The mean SNQ was 5.2 ± 4.5 for the STG group and 5.9 ± 3.7 for the ST4 group ( P = .5100). The mean tibial tunnel widening was 93.7% ± 51.7% for the STG group versus 80.0% ± 42.9% for the ST4 group ( P = .2605). The groups did not differ in signal intensity at the bone-graft interface ( P = .7502) or in graft signal according to the Howell scale ( P = .4544). CONCLUSION: At the 1-year postoperative follow-up, incorporation and ligamentization of the STG and ST4 grafts were the same based on MRI analysis. The results were at least as good with the ST4 technique as with the standard STG technique in terms of incorporation and ligamentization

Emission de polluants gazeux dans les bâtiments à partir d'un sol pollué : comparaison mesures sur sites et modélisations

National audienceDans le domaine des sites pollués par des composés organiques volatils, la migration depuis les sols et les eaux souterraines vers l'air ambiant de bâtiments est souvent le principal vecteur d'exposition en termes de risques sanitaires liés à la voie inhalation. La quantification, prédictive et par la mesure, du transfert de vapeurs (et donc des concentrations dans l'air intérieur des bâtiments) est essentielle pour une gestion des sites pollués protectrice de la santé des personnes. La mesure directe sur le compartiment environnemental est généralement privilégiée, cette dernière devant cependant être pertinente, représentative du site considéré, et basée sur une stratégie d'échantillonnage adaptée, tant au niveau spatial que temporel. L'évaluation du transfert de substances émises par le sol vers l'air ambiant des bâtiments est entachée encore aujourd'hui d'importantes incertitudes d'un point de vue tant qualitatif que quantitatif. En effet, l'état de l'art actuel et le retour d'expérience montrent que les modélisations peuvent conduire à des évaluations de concentrations dans l'air intérieur d'un bâtiment indiquant des différences de plusieurs ordres de grandeur, les sous-estimant ou les surestimant. Face à ces incertitudes dans les évaluations quantitatives des risques sanitaires, et afin de mettre en place des gestions de sites plus pertinentes, l'étude réalisée visait à examiner l'efficacité des modèles de transferts existants ou développé par l'INERIS, par la comparaison des concentrations prédites dans l'air ambiant intérieur de bâtiments avec les mesures de terrain sur deux sites expérimentaux, avec un contrôle approfondi des paramètres sensibles de la modélisation

CANDIDA ALBICANS, CANDIDA DUBLINIENSIS, CANDIDA GLABRATA (REVUE BIBLIOGRAPHIQUE SUR LES METHODES D'IDENTIFICATION ET MISE EN EVIDENCE DE CONSTITUTANTS DE SURFACE REMARQUABLES)

ANGERS-BU Médecine-Pharmacie (490072105) / SudocSudocFranceF

Synthèse bibliographie des valeurs repères et réglementaires dans l’air intérieur à l’échelle internationale en lien avec les sites et sols pollués

International audienc

Transfer of volatile compounds from soil : comparison between predictions and field measurements with different models ; development of the volasoil model for a depleting source

International audienceSoil vapour migration into buildings, and subsequent inhalation, are often the main exposure pathway to humans at sites contaminated with Volatile Organic Compounds (VOCs). For such sites, the quantification of pollutant concentrations in the indoor air is essential while assessing risks for the human health. Modeling is often necessary, for example in the view of future situations, but also in combination with site measurements. The Johnson & Ettinger and VOLASOIL models are the two models mainly used in Europe to predict indoor air concentrations. The validation of these models is still incomplete, beyond some global verification of indoor air concentrations: step by step measurements for a detailed model calibration and "validation" hardly exist in the literature, and predictions of indoor air concentrations from different models sometimes vary by several orders of magnitude. Verifying and improving vapour intrusion models is necessary for a better risk estimation and subsequent site management. Besides, the VOLASOIL model does not represent the depletion of the source due to the volatilization, beyond an overall mass control; this may result in over-conservative estimates of indoor air concentrations, for example when a VOC source is near the soil surfac

Knowledge, evaluation and impact management of urban garden soils, looking back on 30 years of research

COMInternational audienceWould you like to receive more information about applying for a grant once this becomes available?: No Content: (1) Vegetable gardens: between renewed interest and vigilance - With the increasing artificialisation of urban and peri-urban soils, the demand for nature in cities is regaining real vigour. This is almost unexpected for vegetable gardens. Indeed, three to four decades ago the cultivation of vegetable gardens at home or in collective gardens was obsolete, in particular due to access to fruit and vegetables facilitated by intensive agriculture. Today, if the economic interest of the vegetable garden continues, the reasons for this revival are more in the social bond, the practice of a physical activity or the will to eat healthy. However, the dynamics of this form of urban agriculture and in particular vegetable gardens can be translated into hasty projects for which certain elements of "common sense" would be neglected. Thus, the extension of the city over the city leads to changes in land use that can, for example, increase the exposure of populations to pollutants. The compatibility between the state of the environment and the uses must then be checked; this exercise is not always easy given the diversity of the situations encountered. (2) A range of projects and actors: from disciplinary case studies to multidisciplinary projects - An inventory is proposed, carried out on the one hand, on the basis of the main lessons learned from research projects and studies carried out and on the other hand, through the collection of information from various actors. For this, we supplemented our own knowledge with a bibliographic work carried out on the basis of almost 30 major research projects, more than 150 international publications and a collection of information from a dozen actors in the field via a targeted survey. After describing the garden ecosystem and the actors involved in it’s functioning, we present the historical evolution, since the 1990s, of the concepts and associated approaches. The different compartments of the ecosystem are then presented, before identifying the main scientific results obtained and their promotion in the form of approaches and tools for garden management. (3) Understanding garden soils to better manage them: main achievements and prospects - The research carried out has made it possible to acquire knowledge about vegetable gardens, the agronomic characteristics of their soils, their degree of fertility and contamination and that of vegetables, exposure to pollutants from populations associated with gardening and the management measures to be implemented if necessary. The results of this work demonstrated the complexity of the "garden" socio-ecosystem, the very high variability in the quality of soils and crops and the existence of transfers of certain pollutants within the food chain. Based on the knowledge limits identified, finalized research perspectives are then proposed with the aim of informing and training even more the multiple actors concerned by the challenges linked to vegetable gardens