HAL-INERIS
Not a member yet
8807 research outputs found
Sort by
Development of a pregnancy-physiologically based toxicokinetic (p-PBTK) model for high-throughput screening of chemicals
No full textInternational audienc
Assessment of functional nanomaterials in medical applications: can time mend public and occupational health risks related to the products’ fate?
No full textInternational audienceSurface coatings are one promising option to prevent bacterial adhesion and biofilm formation given the prevalence of antibiotic resistant bacterial strains. Titanium dioxide (TiO2) is presently considered to be the only photocatalytic material suitable for commercial use, although the toxicity risks of TiO2, particularly in its nanoparticulate form, have not been fully addressed. The aim of this study was to determine release of nanoparticles (NPs) from functional materials for medical applications and their aerosol formation. Further, the fate of the material with respect to its product lifetime was investigated. The present study examined the risk of NP exposure since released submicronic and inhalable manufactured nano-objects, their agglomeraates or aggregates containing Ti were detected. The coating of the material magnifies its emission levels when comparing the obtained product properties to those of an uncoated sample. The evolution of release tendecy with the material’s time of use shows that release does not vanish upon continuous material losses induced by the release, thus the risk does not diminish with time. Consequently, this nanomaterial TiO2 needs to be avoided in healthcare settings, or, alternatively, new TiO2-deposition techniques are required to be developed
Prediction of effects on chemicals on three-spined stickleback populations in mesocosms
No full textInternational audienceTo improve environmental risk assessment, mechanistic models predicting the impacts of toxicants on populations such as individual-based models (IBMs) was suggested as relevant tools. Furthermore, IBMs can be coupled with DEB (Dynamic Energy Budget) models which describe physiological processes of an organism. However, the development of DEB-IBMs requires a large number of data on the organism and the population dynamics which make them difficult to build. To this aim, data from mesocosm experiments can be of great interest for developing and calibrating DEB-IBMs. One of the species that can be used in mesocosm experiments is the three-spined stickleback (Gasterosteus aculeatus). Furthermore, the ecology and biology of this teleost fish is relatively well-known and a DEB model for this organism has already been developed. In this study, we used data from several mesocosm experiments to describe stickleback populations under control conditions, and exposed to three concentrations of an endocrine disruptor, the Bisphenol A (BPA, 1, 10 and 100 µg/L). First, using two set of experiments in control conditions, different ways of integrated temperature and food data was tested in order to assess the relevance of the DEB model calibrated with laboratory data for sticklebacks in mesocosms. Then, the DEB-IBM was developed and calibrated and simulated endpoints of the population dynamics in control conditions were compared to the observed enpoints of the population dynamics in control conditions or exposed to BPA. We showed that the DEB model successfully predicted the growth of mature male and female sticklebacks for two set of experiments in control conditions. Furthermore, the calibrated DEB-IBM successfully predicted dynamics of stickleback populations during mesocosm experiments in control conditions. Indeed, the different descriptive variables of the populations (population size, male, female and juvenile frequencies, lengths and coefficient of variations) were well described and were used to compare with the endpoints of mesocosms exposed to BPA. In conclusion, simulated enpoints of stickleback populations can thus be used as a baseline to compare exposed populations to BPA in order to improve environmental risk assessment. In a second step, the DEB-IBM could be adapted in order to introduce the effects of toxicants such as BPA on the individuals and thus extrapolate the effects at the population level
Sismicité anthropique : synthèse sur l'aléa et les risques associés
No full textInternational audienceThe risk of human seismicity poses new challenges both in terms of hazard characterization and risk assessment and management. The synthesis presented here, is based on an extensive literature review and analysis of recent and emblematic cases. However, these cases are rare in view of the number of projects around the world.Le risque de sismicité anthropique soulève de nouveaux défis en termes de connaissances, d’évaluation de l’aléa et de gestion du risque. La synthèse présentée ici, s’appuie sur une vaste étude bibliographique et l’analyse de cas récents ou emblématiques. Ces cas restent néanmoins rares au regard du nombre de projets à travers le monde
Two-scale multi-model ensemble : is a hybrid ensemble of opportunity telling us more ?
No full textInternational audienceIn this study we introduce a hybrid ensemble consisting of air quality models operating at both the global and regional scale. The work is motivated by the fact that these different types of models treat specific portions of the atmospheric spectrum with different levels of detail, and it is hypothesized that their combination can generate an ensemble that performs better than mono-scale ensembles. A detailed analysis of the hybrid ensemble is carried out in the attempt to investigate this hypothesis and determine the real benefit it produces compared to ensembles constructed from only global-scale or only regional-scale models. The study utilizes 13 regional and 7 global models participating in the Hemispheric Transport of Air Pollutants phase 2 (HTAP2)–Air Quality Model Evaluation International Initiative phase 3 (AQMEII3) activity and focuses on surface ozone concentrations over Europe for the year 2010. Observations from 405 monitoring rural stations are used for the evaluation of the ensemble performance. The analysis first compares the modelled and measured power spectra of all models and then assesses the properties of the mono-scale ensembles, particularly their level of redundancy, in order to inform the process of constructing the hybrid ensemble. This study has been conducted in the attempt to identify that the improvements obtained by the hybrid ensemble relative to the mono-scale ensembles can be attributed to its hybrid nature. The improvements are visible in a slight increase of the diversity (4 % for the hourly time series, 10 % for the daily maximum time series) and a smaller improvement of the accuracy compared to diversity. Root mean square error (RMSE) improved by 13–16 % compared to G and by 2–3 % compared to R. Probability of detection (POD) and false-alarm rate (FAR) show a remarkable improvement, with a steep increase in the largest POD values and smallest values of FAR across the concentration ranges. The results show that the optimal set is constructed from an equal number of global and regional models at only 15 % of the stations. This implies that for the majority of the cases the regional-scale set of models governs the ensemble. However given the high degree of redundancy that characterizes the regional-scale models, no further improvement could be expected in the ensemble performance by adding yet more regional models to it. Therefore the improvement obtained with the hybrid set can confidently be attributed to the different nature of the global models. The study strongly reaffirms the importance of an in-depth inspection of any ensemble of opportunity in order to extract the maximum amount of information and to have full control over the data used in the construction of the ensemble
Numerical anisotropic modelling of a deep drift at the Meuse/Haute-Marne URL
No full textInternational audienceThe development of nuclear energy raised the issue of radioactive waste disposal in deep geological formations. Clay formations in their natural state show very favorable confining conditions as repositories for radioactive waste due to their generally low values of hydraulic conductivity and significant retention capacity for radionuclides. Three clay formations in Europe are currently being studied in details as potential host rocks for high level radioactive waste disposal, i.e. the Boom Clay in Belgium, the Opalinus Clay in Switzerland and the Callovo- Oxfordian Claystone (COx) in France. Lastly, the French national radioactive waste management agency (Andra) started building the underground research laboratory (URL) at Bure in the Meuse district. Several specific in situ experiments were carried out with the main objectives in term of underground civil engineering to: (a) evaluate the geological environment of the future Deep Geological Repository (DGR), (b) collect data from the clay formation in order to assess the performances of the future DGR, (c) test and demonstrate the feasibility of the future DGR. The feedback of these experiments and in situ measurements as well as the numerous theoretical analyzes and numerical modeling works undertaken on the COx allowed to identify the key mechanisms (mainly in the framework of THM processes) governing the behavior of the COx [1]. In addition to the THM processes and the associated parameters, it appears necessary to consider the anisotropies (mechanical, hydraulic and thermal) of such rock, but also its time-dependent behavior. This paper deals with these issues
Combinaison de mesures automatiques et manuelles pour l’étude des sources de l’aérosol organique
No full textInternational audienceThe present study proposes a novel approach to combine online and offline measurements in statistical source-receptor model such as Positive matrix factorization (PMF). Offline measurements include here POA (primary organic aerosol) and SOA (secondary organic aerosol) molecular markers. Their combination with data obtained using an Aerosol Chemical Speciation Monitor (ACSM) notably allowed for a better deconvolution of SOA fractions - at short time resolution (30min) - of SOA fractions than usually not obtained with online measurements only.Ces travaux proposent une nouvelle approche permettant de combiner des mesures automatiques et manuelles de la composition chimique des aérosols à l’aide d’un modèle statistique de type “Positive Matrix Factorization” (PMF). Les mesures manuelles incluent des marqueurs moléculaires spécifiques des aérosols organiques primaires et secondaires (AOP et AOS). La combinaison de ces mesures avec les données issues d’un Aerosol Chemical Speciation Monitor (ACSM) a notamment permis d’obtenir une meilleure discrimination des différentes fractions de l’AOS - sur un pas de temps court (30min) – que ce qu’il est générallement réalisé à l’aide des seules mesures automatiques
Simulating the blast wave from detonation of a charge using a balloon of compressed air
No full textInternational audienceThis paper investigates a simple numerical method, based on the release of a pressurized spherical air volume, to predict or reproduce the main characteristics of the blast environment from the detonation of solid or gaseous charges. This approach aims to give an alternative to the use of a steady-state detonation model and a Jones-Wilkins-Lee equation of state to describe the expansion of the detonation products, especially when the explosive parameters are unknown and a TNT equivalent is used. The validity of the proposed approach is assessed through the comparison of predicted overpressure and impulse at different distances from the explosion with that of TNT and stoichiometric propane-oxygen explosions. It is also shown that, for gaseous detonations, a better agreement is obtained with the rationally optimized compressed balloon than with the use of a Jones-Wilkins-Lee model and a TNT equivalent mass
An experimental evaluation of toxic gas emissions from vehicle fires
No full textInternational audienceImproving fire modelling is a key issue to design efficient safety measures for a safe people evacuation in case of fire. Such an analysis should consider the different impacts of fire on people as temperature, visibility but also toxicity. Most of the standard curves used in tunnel fire studies are based on quite old fire tests without any detailed toxic gas qualification. Very few fire tests were published in that way. Based on those few tests, some standard fire emission factors are available in the literature. The objective of this paper is to review those emission factors considering the different toxic species and dealing with using recent cars. A method is then proposed to define a carbon monoxide equivalent emission factor to consider the different species through their specific threshold. Such an approach can be easily introduced into fire codes. To meet this objective, two series of tests were performed. The first concerns individual combustible materials of cars as plastics and tyres. The second focusses on full car burning tests including a detailed smoke analysis. Those two series of tests lead to an analysis of the smoke toxicity and a comparison of emission factors with standard ones
