Characterisation of toxic gaseous emissions from industrial solid waste landfills

International audienceIn France, Hazardous Industrial Waste, once stabilized, are buried in specific landfills. As for all polluting activities, these facilities must report to the EPER Register their toxic gaseous emissions, expressed in mass per year, as soon as they exceed threshold limit values. Campaigns were conducted on two different hazardous waste landfills in order to establish if these facilities needed to report to EPER register. Global fluxes of gaseous components were measured by means of an FID (hydrocarbons) and a PID (halocarbons, aromatics and some non-organic compounds). Specific concentrations of aromatic (BTEX) and chlorinated hydrocarbons were also measured. Gaseous emissions were generally very low. Emissions were only detected for young and medium-aged layers, between 1 day and 3 months old. Due to these low emissions, and to the small surfaces involved, the two landfills do not fall under the EPER emission Register

Online networks of eating-disorder websites: why censoring pro-ana might be a bad idea

Dr AA Casilli from Telecom ParisTech, F Pailler from the Edgar Morin Centre and Dr P Tubaro from the University of Greenwich demonstrate how the reshaping and censoring of online ana-mia communities is bad news for health care providers and policy makers

Refrigeration System for the ATLAS Experiment

The proposed ATLAS detector for the 27 km circumference LHC collider is of unprecedented size and complexity. The magnet configuration is based on an inner superconducting solenoid and large superconducting air-core toroids (barrel and two end-caps) each made of eight coils symmetrically arranged outside the calorimetry. The total cold mass approaches 600 tons and the stored energy is 1.7 GJ. The cryogenic infrastructure will include a 6 kW @ 4.5 K refrigerator, a precooling unit and distribution systems and permits flexible operation during cool-down, normal running and quench recovery. A dedicated LN2 refrigeration system is proposed for the three liquid argon calorimeters (84 m3 of LAr). Magnets and calorimeters will be individually tested prior to their definitive installation in a large scale cryogenic test area on the surface. The experiment is scheduled to be operational in 2005

Effects of Phenol Addition on Oil Extraction from Moroccan Oil Shale by Supercritical Toluene

In the present work, the effect of phenol on the supercritical extraction of the organic matter from Tarfaya's oil shale with toluene was evaluated. The experimental results showed clearly that phenol had a significant effect on the yield and the composition of the oils obtained. Moreover, it was shown that phenol was a very efficient modifier for oil shale, giving a good yield of recovery and a suitable maturation of the organic matter. The pitches prepared by mixing phenol and toluene contain more aromatics and have a high char yield at 950 °C compared to those obtained by extraction with supercritical toluene alone

Gaia Focused Product Release: Spatial distribution of two diffuse interstellar bands

Diffuse interstellar bands (DIBs) are absorption features seen in optical and infrared spectra of stars that are probably caused by large and complex molecules in the ISM. Here we investigate the Galactic distribution and properties of two DIBs identified in almost six million stellar spectra collected by the Gaia Radial Velocity Spectrometer. These measurements constitute a part of the Gaia Focused Product Release to be made public between the Gaia DR3 and DR4 data releases. In order to isolate the DIB signal from the stellar features in each individual spectrum, we identified a set of 160 000 spectra at high Galactic latitudes which we consider to be the DIB-free reference sample. Matching each target spectrum to its closest reference spectra in stellar parameter space allowed us to remove the stellar spectrum empirically, without reference to stellar models, leaving a set of six million ISM spectra. Identifying the two DIBs at 862.1 nm and 864.8 nm in the stacked spectra, we modelled their shapes and report the depth, central wavelength, width, and equivalent width (EW) for each, along with confidence bounds on these measurements. Our main results are as follows: (1) the strength and spatial distribution of the DIB $\lambda$862.1 are very consistent with what was found in Gaia DR3, but for this work we attained a higher signal-to-noise ratio in the stacked spectra to larger distances, which allowed us to trace DIBs in the outer spiral arm and beyond the Scutum--Centaurus spiral arm; (2) we produced an all-sky map below ${\pm}65^{\circ}$ of Galactic latitude to $\sim$4000 pc of both DIB features and their correlations; (3) we detected the signals of DIB\,$\lambda$862.1 inside the Local Bubble; and (4) there is a reasonable correlation with the dust reddening found from stellar absorption and EWs of both DIBs.Comment: 29 pages, accepted for publication in A&

Comparison of chemical and physical activation processes at obtaining adsorbents from moroccan oil shale

Within the Moroccan natural resources valorisation scheme, new adsorbents have been prepared from oil shale by chemical and physical activation processes. The activation process the authors have developed in this study give effective adsorbent materials. In view of the physico-chemical properties of these materials and application to the treatment of water loaded with a metal (Cr6+ ion) or organic (methylene blue (MB)) pollutant, it is concluded that the chemical activation process of oil shale at low temperature (250 °C) affords the best material. The material’s yield is good in comparison with the physical activation at the same temperature and the process is energy saving differently from that at 450 °C. Moreover, the chemical activation of oil shale with phosphoric acid at 250 °C produces a material with a good yield (about 70%), a high specific surface area (approximately 600 m2 /g) and a highly porous structure, which gives it a high retention of methylene blue and the Cr6+ ion

<i>Gaia</i> Data Release 1. Summary of the astrometric, photometric, and survey properties

Context. At about 1000 days after the launch of Gaia we present the first Gaia data release, Gaia DR1, consisting of astrometry and photometry for over 1 billion sources brighter than magnitude 20.7. Aims. A summary of Gaia DR1 is presented along with illustrations of the scientific quality of the data, followed by a discussion of the limitations due to the preliminary nature of this release. Methods. The raw data collected by Gaia during the first 14 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC) and turned into an astrometric and photometric catalogue. Results. Gaia DR1 consists of three components: a primary astrometric data set which contains the positions, parallaxes, and mean proper motions for about 2 million of the brightest stars in common with the HIPPARCOS and Tycho-2 catalogues – a realisation of the Tycho-Gaia Astrometric Solution (TGAS) – and a secondary astrometric data set containing the positions for an additional 1.1 billion sources. The second component is the photometric data set, consisting of mean G-band magnitudes for all sources. The G-band light curves and the characteristics of ∼3000 Cepheid and RR-Lyrae stars, observed at high cadence around the south ecliptic pole, form the third component. For the primary astrometric data set the typical uncertainty is about 0.3 mas for the positions and parallaxes, and about 1 mas yr−1 for the proper motions. A systematic component of ∼0.3 mas should be added to the parallax uncertainties. For the subset of ∼94 000 HIPPARCOS stars in the primary data set, the proper motions are much more precise at about 0.06 mas yr−1. For the secondary astrometric data set, the typical uncertainty of the positions is ∼10 mas. The median uncertainties on the mean G-band magnitudes range from the mmag level to ∼0.03 mag over the magnitude range 5 to 20.7. Conclusions. Gaia DR1 is an important milestone ahead of the next Gaia data release, which will feature five-parameter astrometry for all sources. Extensive validation shows that Gaia DR1 represents a major advance in the mapping of the heavens and the availability of basic stellar data that underpin observational astrophysics. Nevertheless, the very preliminary nature of this first Gaia data release does lead to a number of important limitations to the data quality which should be carefully considered before drawing conclusions from the data

Eclogite or jadeitite: The two colours involved in the transfer of alpine axeheads in western Europe

During the 5th and 4th millennia BC, the Neolithic extraction of stone around Mont Viso and in the Mont Beigua massif in the north Italian Alps resulted in the production of large polished axeheads in ecologite, omphacitite, jadeitite and amphibolite - raw materials which were not only rare but which also have remarkable mechanical and aesthetic properties. These axeheads circulated around western Europe over great distances and in particular, between the Alps, the Atlantic and the North Sea. Among these Alpine jades, research suggests a tendency for different raw materials to be represented in different geographic areas. Axeheads and other items made from dark-coloured rocks from the family of eclogites and omphacitites tend to predominate in the Paris Basin, in Germany and in Great Britain and Ireland. This paper documents the manufacture, circulation and deposition of different types of Alpine axeheads over time. More specifically, it discusses observed trends in relation to variability in the supply of raw materials and finished objects, the nature of regional traditions and long-distance transfer, and ultimately, the changing significance of axeheads as socially valorized artefacts

Ultracool dwarfs in Gaia DR3

Aims. In this work we use the Gaia DR3 set of ultracool dwarf candidates and complement the Gaia spectrophotometry with additional photometry in order to characterise its global properties. This includes the inference of the distances, their locus in the Gaia colour-absolute magnitude diagram and the (biased through selection) luminosity function in the faint end of the Main Sequence. We study the overall changes in the Gaia RP spectra as a function of spectral type. We study the UCDs in binary systems, attempt to identify low-mass members of nearby young associations, star forming regions and clusters, and analyse their variability properties. Results. We detect 57 young, kinematically homogeneous groups some of which are identified as well known star forming regions, associations and clusters of different ages. We find that the primary members of 880 binary systems with a UCD belong mainly to the thin and thick disk components of the Milky Way. We identify 1109 variable UCDs using the variability tables in the Gaia archive, 728 of which belong to the star forming regions defined by HMAC. We define two groups of variable UCDs with extreme bright or faint outliers. Conclusions. The set of sources identified as UCDs in the Gaia archive contains a wealth of information that will require focused follow-up studies and observations. It will help to advance our understanding of the nature of the faint end of the Main Sequence and the stellar/substellar transition.Comment: Accepted by Astronomy and Astrophysics. 29 pages, 20 figures plus 3 appendice