Multi-walled Carbon Nanotubes, NM-400, NM-401, NM-402, NM-403: Characterisation and Physico-Chemical Properties

In 2011 the JRC launched a Repository for Representative Test Materials that supports both EU and international research projects, and especially the OECD Working Party on Manufactured Nanomaterials' (WPMN) exploratory testing programme "Testing a Representative set of Manufactured Nanomaterials" for the development and collection of data on characterisation, toxicological and ecotoxicological properties, as well as risk assessment and safety evaluation of nanomaterials. The JRC Repository responds to a need for availability of nanomaterial from a single production batch to enhance the comparability of results between different research laboratories and projects. The present report presents the physico-chemical characterisation of the multi-walled carbon nanotubes (MWCNT) from the JRC Repository: NM-400, NM-401, NM-402 and NM-403. NM-400 was selected as principal material for the OECD WPMN testing programme. They are produced by catalytic chemical vapour deposition. Each of these NMs originates from one respective batch of commercially manufactured MWCNT. They are nanostructured, i.e. they consist of more than one graphene layer stacked on each other and rolled together as concentric tubes. The MWCNT NMs may be used as a representative material in the measurement and testing with regard to hazard identification, risk and exposure assessment studies. The results are based on studies by several European laboratories participating to the NANOGENOTOX Joint Action.JRC.I.4-Nanobioscience

Titanium Dioxide, NM-100, NM-101, NM-102, NM-103, NM-104, NM-105: Characterisation and Physico-Chemical Properties

The European Commission's Joint Research Centre (JRC) provides scientific support to European Union policy including nanotechnology. Within this context, the JRC launched, in February 2011, a repository for Representative Test Materials (RTMs), based on preparatory work started in 2008. It supports both EU and international research projects, and especially the OECD Working Party on Manufactured Nanomaterials (WPMN). The WPMN leads an exploratory testing programme "Testing a Representative set of Manufactured Nanomaterials" for the development and collection of data on characterisation, toxicological and ecotoxicological properties, as well as risk assessment and safety evaluation of nanomaterials. The purpose is to understand the applicability of the OECD Test Guidelines for the testing of nanomaterials as well as end-points relevant for such materials. The Repository responds to a need for nanosafety research purposes: availability of nanomaterial from a single production batch to enhance the comparability of results between different research laboratories and projects. The availability of representative nanomaterials to the international scientific community furthermore enhances and enables development of safe materials and products. The present report presents the physico-chemical characterisation of the Titanium dioxide series from the JRC repository: NM-100, NM-101, NM-102, NM-103, NM-104 and NM-105. NM-105 was selected as principal material for the OECD test programme "Testing a representative set of manufactured nanomaterials". NM-100 is included in the series as a bulk comparator. Each of these NMs originates from one batch of commercially manufactured TiO2. The TiO2 NMs may be used as representative material in the measurement and testing with regard to hazard identification, risk and exposure assessment studies. The results for more than 15 endpoints are addressed in the present report, including physico-chemical properties, such as size and size distribution, crystallite size and electron microscopy images. Sample and test item preparation procedures are addressed. The results are based on studies by several European laboratories participating to the NANOGENOTOX Joint Action, as well as by the JRC.JRC.I.4-Nanobioscience

Étude de la mise en suspension de particules lors de l impact de gouttes

L impact de gouttes sur des surfaces est rencontré dans de nombreux procédés industriels et lors de processus naturels. L'étude de ce phénomène est fondamentale afin d évaluer les sources potentielles de contamination dans le cas de scénarios de chutes de liquide sous forme de train de gouttes. Il y a très peu de données dans la littérature sur la mise en suspension dans le cas de l impact de gouttes millimétriques. Le but de nos travaux est d étudier expérimentalement l émission de particules pendant l impact de gouttes sur un film liquide. Des expériences ont été réalisées afin d étudier l influence de la vitesse d impact et du diamètre des gouttes, de l épaisseur du film liquide, de la tension de surface et de la viscosité du liquide sur la mise en suspension de microgouttelettes. Nos résultats, originaux, ont permis de valider l utilisation de relations semi-empiriques déjà existantes, décrivant la transition entre les régimes de dépôt et d éclaboussure, afin de déterminer la présence ou non de particules mises en suspension. Les microgouttelettes émises, de diamètre inférieur à cinquante micromètres, ont été caractérisées en termes de quantité et de distribution granulométrique. Nos résultats montrent l influence combinée des paramètres étudiés sur la mise en suspension. Pour cette raison, il est intéressant d utiliser les nombres adimensionnels, permettant de décrire le rapport entre les forces inertielles, de viscosité et de tension de surface, afin de comprendre physiquement la mise en suspension des particules.A liquid droplet impinging onto surfaces occurs in many industrial and natural processes. The study of this phenomenon is fundamental in order to determine the potential sources of contamination in the case of scenarios of liquid falls such as dripping. There are very few data in the literature in the case of the impact of millimeter-size droplets. The purpose of our work is to study experimentally the particle emission during the impact of droplets onto a liquid film. Experiments were conducted to study the influence of the velocity and the diameter of the droplets, the height of the liquid film, the surface tension and viscosity of the liquid on the airborne particles. Our results, original, have made it possible to examine the relevance of existing relations, describing the transition between deposition and splash regimes, in order to determine the presence or not of airborne particles. The microdroplets produced, with diameters less than fifty micrometers, are characterised in terms of total mass and size distribution. Our results also show the influence of a combination of several factors on the production of airborne particles. For this reason, it is interesting to use dimensionless numbers, to describe the relationship between the inertial, viscosity and surface tension forces, in order to understand physically the emission of airborne particles.PARIS12-Bib. électronique (940280011) / SudocSudocFranceF

Sub-µm air-gap resonant MEMS mass sensors fabrication and electrical characterization for the detection of airborne particles

International audienc

Fabrication, electrical characterization and sub-ng mass resolution of sub-μm air-gap bulk mode MEMS mass sensors for the detection of airborne particles

International audienc

Aerosol release fraction by concrete scarifying operations and its radiological impacts on the dismantling of nuclear facilities

International audienceThe sanitation of concrete structures through dismantling of nuclear buildings is complicated by the radiological threat associated with the airborne release of fine dust. This is the reason why the aerosol release fraction (ARF) associated with mechanical removal of concrete structure containing radioactivity needs to be accurately evaluated to implement efficient radiological survey. We characterize experimentally the ARF resulting from milling operations on a standard concrete slab in a confined experimental chamber using an industrial scarifying machine. Our results reveal a significant production of fine aerosol particles with a mass median aerodynamic diameter close to 4 µm and which mineralogical composition is dominated by calcium and silica compounds. The ARF measured when a vacuum suction device is used to confine the dust production close to the source is on the order of 5×10-4; the maximum ARF estimated when no suction device is used is on the order of 0.5

Etude de la remise en suspension d’aérosol par des opérations d’écroutage de béton

International audienceNous présentons une étude expérimentale dédiée à la mesure de la fraction d’aérosol remise en suspension dans l’air pendant les opérations de déconstruction du béton, pour des applications en sûreté nucléaire. La quantité totale de particules remises en suspension est évaluée à l’aide de préleveurs à haut débit associés à un compteur optique de particules. Un intérêt particulier est accordé aux particules dans les fractions conventionnelles alvéolaire et thoracique par une analyse de leur distribution granulométrique. Il convient de mentionner que le travail a été réalisé en l’absence de radioactivité. Toutefois, les résultats devraient être facilement transposables aux structures en béton des installations nucléaires exposées au flux neutronique, pour lesquelles les scénarios d’activation sont bien définis

Etude de la remise en suspension d’aérosol par des opérations d’écroutage de béton

International audienceNous présentons une étude expérimentale dédiée à la mesure de la fraction d’aérosol remise en suspension dans l’air pendant les opérations de déconstruction du béton, pour des applications en sûreté nucléaire. La quantité totale de particules remises en suspension est évaluée à l’aide de préleveurs à haut débit associés à un compteur optique de particules. Un intérêt particulier est accordé aux particules dans les fractions conventionnelles alvéolaire et thoracique par une analyse de leur distribution granulométrique. Il convient de mentionner que le travail a été réalisé en l’absence de radioactivité. Toutefois, les résultats devraient être facilement transposables aux structures en béton des installations nucléaires exposées au flux neutronique, pour lesquelles les scénarios d’activation sont bien définis

An experimental approach to measure particle deposition in large circular ventilation ducts

International audienceThe topic of this study is related to airborne particle dynamics in indoor environments. Lab-scale experiments have been performed to investigate particle deposition velocity to six different surfaces orientations (with respect to gravity) for fully developed turbulent flow in horizontal large circular ventilation ducts. Monodispersed aerosol particles (1–6 μm) were used in the deposition experiments. A very low particle mass (40 ng) was measured reliably above background level on duct surfaces by a means of a nondestructive stencil technique associated with fluorescence analysis. For 2–6 μm particles (diffusion and impaction regime), deposition rates to floors were much greater than rates to the ceiling and greater than rates to the wall. For 1-μm particles, the effect of surface orientation to particle deposition was not significant. Results were compared to the very few similar and published studies. This work was conducted in the frame of the CleanAirNet project which aimed at producing new knowledge, models, and techniques to help controlling the safety food stuffs, through a better control of aerosol particle (bioaerosols) transport and deposition in the ventilation networks of the food industry