Nanoparticles filtration by leaked fibrous filters

Explosion risks from nanomaterials

International audienceEmerging nanomanufactured products are being incorporated in a variety of consumer products ranging from closer body contact products (i.e. cosmetics, sunscreens, toothpastes, pharmaceuticals, clothing) to more remote body-contact products (electronics, plastics, tires, automotive and aeronautical), hence posing potential health and environmental risks. The new field of nanosafety has emerged and needs to be explored now rather than after problems becomes so ubiquitous and difficult to treat that their trend become irreversible. Such endeavour necessitates a transdisciplinary approach. A commonly forgotten and/or misunderstood risk is that of explosion/detonation of nanopowders, due to their high specific active surface areas. Such risk is emphasized and illustrated with the present development of an appropriate risk analysis. For this particular risk, a review of characterization methods and their limitations with regard to nanopowders is presented and illustrated for a few organic and metallic nanopowders

Structure of spinel at high temperature usingin-situXANES study at the Al and Mg K-edge

Kinetics of iron redox reaction in silicate melts: A high temperature Xanes study on an alkali basalt

In Earth and Materials sciences, iron is the most important transition element. Glass and melt properties are strongly affected by iron content and redox state with the consequence that some properties (i.e. viscosity, heat capacity, crystallization...) depend not only on the amounts of Fe2+ and Fe3+, but also on the coordination state of these ions. In this work we investigate iron redox reactions through XANES experiments at the K-edge of iron. Using a high-temperature heating device, pre-edge of XANES spectra exhibits definite advantages to make in-situ measurements and to determine the evolution of redox state with time, temperature and composition of synthetic silicate melts. In this study, new kinetics measurements are presented for a basalt melt from the 31,000-BC eruption of the Puy de Lemptegy Volcano in France. These measurements have been made between 773 K and at superliquidus temperatures up to 1923 K.

A comparative study of actinide complexation in three ligand systems with increasing complexity

Commissioning of the CMS High Level Trigger

The CMS experiment will collect data from the proton-proton collisionsdelivered by the Large Hadron Collider (LHC) at a centre-of-mass energy up to14 TeV. The CMS trigger system is designed to cope with unprecedentedluminosities and LHC bunch-crossing rates up to 40 MHz. The unique CMS triggerarchitecture only employs two trigger levels. The Level-1 trigger isimplemented using custom electronics, while the High Level Trigger (HLT) isbased on software algorithms running on a large cluster of commercialprocessors, the Event Filter Farm. We present the major functionalities of theCMS High Level Trigger system as of the starting of LHC beams operations inSeptember 2008. The validation of the HLT system in the online environment withMonte Carlo simulated data and its commissioning during cosmic rays data takingcampaigns are discussed in detail. We conclude with the description of the HLToperations with the first circulating LHC beams before the incident occurredthe 19th September 2008.

MPGDs in Compton imaging with liquid-xenon

The interaction of radiation with liquid xenon, inducing both scintillationand ionization signals, is of particular interest for Compton-sequencesreconstruction. We report on the development and recent results of aliquid-xenon time-projection chamber, dedicated to a novel nuclear imagingtechnique named "3 gamma imaging". In a first prototype, the scintillation isdetected by a vacuum photomultiplier tube and the charges are collected with aMICROMEGAS structure; both are fully immersed in liquid xenon. In view of thefinal large-area detector, and with the aim of minimizing dead-zones, we areinvestigating a gaseous photomultiplier for recording the UV scintillationphotons. The prototype concept is presented as well as preliminary results inliquid xenon. We also present soft x-rays test results of a gaseousphotomultiplier prototype made of a double Thick Gaseous Electron Multiplier(THGEM) at normal temperature and pressure conditions.

An accurate equation of state for the one component plasma in the low coupling regime

An accurate equation of state of the one component plasma is obtained in thelow coupling regime $0 \leq \Gamma \leq 1$. The accuracy results from a smoothcombination of the well-known hypernetted chain integral equation, Monte Carlosimulations and asymptotic analytical expressions of the excess internal energy$u$. In particular, special attention has been brought to describe and takeadvantage of finite size effects on Monte Carlo results to get thethermodynamic limit of $u$. This combined approach reproduces very accuratelythe different plasma correlation regimes encountered in this range of values of$\Gamma$. This paper extends to low $\Gamma$'s an earlier Monte Carlosimulation study devoted to strongly coupled systems for $1 \leq \Gamma \leq190$ ({J.-M. Caillol}, {J. Chem. Phys.} \textbf{111}, 6538 (1999)). Analyticalfits of $u(\Gamma)$ in the range $0 \leq \Gamma \leq 1$ are provided with aprecision that we claim to be not smaller than $p= 10^{-5}$. HNC equation andexact asymptotic expressions are shown to give reliable results for $u(\Gamma)$only in narrow $\Gamma$ intervals, i.e. $0 \leq \Gamma \lesssim 0.5$ and $0\leq \Gamma \lesssim 0.3$ respectively.

Constraining future climate change using ice core data

Impact of warm events during cold seasons on the hydrological response of a polar glacier system