The ThomX project status

Work supported by the French Agence Nationale de la recherche as part of the program EQUIPEX under reference ANR-10-EQPX-51, the Ile de France region, CNRS-IN2P3 and Université Paris Sud XI - http://accelconf.web.cern.ch/AccelConf/IPAC2014/papers/wepro052.pdfA collaboration of seven research institutes and an industry has been set up for the ThomX project, a compact Compton Backscattering Source (CBS) based in Orsay - France. After a period of study and definition of the machine performance, a full description of all the systems has been provided. The infrastructure work has been started and the main systems are in the call for tender phase. In this paper we will illustrate the definitive machine parameters and components characteristics. We will also update the results of the different technical and experimental activities on optical resonators, RF power supplies and on the electron gun

<scp>ReSurveyEurope</scp>: A database of resurveyed vegetation plots in Europe

AbstractAimsWe introduce ReSurveyEurope — a new data source of resurveyed vegetation plots in Europe, compiled by a collaborative network of vegetation scientists. We describe the scope of this initiative, provide an overview of currently available data, governance, data contribution rules, and accessibility. In addition, we outline further steps, including potential research questions.ResultsReSurveyEurope includes resurveyed vegetation plots from all habitats. Version 1.0 of ReSurveyEurope contains 283,135 observations (i.e., individual surveys of each plot) from 79,190 plots sampled in 449 independent resurvey projects. Of these, 62,139 (78%) are permanent plots, that is, marked in situ, or located with GPS, which allow for high spatial accuracy in resurvey. The remaining 17,051 (22%) plots are from studies in which plots from the initial survey could not be exactly relocated. Four data sets, which together account for 28,470 (36%) plots, provide only presence/absence information on plant species, while the remaining 50,720 (64%) plots contain abundance information (e.g., percentage cover or cover–abundance classes such as variants of the Braun‐Blanquet scale). The oldest plots were sampled in 1911 in the Swiss Alps, while most plots were sampled between 1950 and 2020.ConclusionsReSurveyEurope is a new resource to address a wide range of research questions on fine‐scale changes in European vegetation. The initiative is devoted to an inclusive and transparent governance and data usage approach, based on slightly adapted rules of the well‐established European Vegetation Archive (EVA). ReSurveyEurope data are ready for use, and proposals for analyses of the data set can be submitted at any time to the coordinators. Still, further data contributions are highly welcome.</jats:sec

Des Méthodes analytiques dédiées aux problématiques environnementales

National audienc

Des Méthodes analytiques dédiées aux problématiques environnementales

National audienc

Impact of Ship Motions on Maritime Radio Links

The improvement of maritime radio links often requires an increase of emitted power or receiver sensitivity. Another way is to replace the poor antenna gains of traditional surface ship whips by novel antenna structures with directive properties. However, ship motions, especially when launches are involved, may affect the radio link quality. Therefore, a tool for modelling the impact of ship motions on such antenna structures was developed. It helps the specification of antenna radiating parameters and improves the radio link performance evaluation. This tool includes a deterministic two-ray model for radio-wave propagation over the sea surface. The geometrical 3D engine for ship motions has the advantage to be compatible with any propagation model and antenna structure

Mass Spectrometry and Ion mobility as a Tool to Investigate Reaction Pathways in Organic Chemistry and more

International audienc

Evaluation of ASAP-IM/MS(/MS) technique for the characterization of PEEK

International audienc

Evaluation of atmospheric solid analysis probe ionization coupled to ion mobility mass spectrometry for characterization of poly(ether ether ketone) polymers

International audienceRecently, the interest of the coupling between atmospheric solid analysis probe (ASAP) and ion mobility– mass spectrometry has been revealed in the field of polymers. This method associates a direct ionization technique with a bi-dimensional separation method. Poly(ether ether ketones) (PEEK) belong to the family of the poly(aryl ether ketones) (PAEK) which are high performance aromatic polymers usually used in aerospace, electronics and nuclear industries. PEEK are important commercial thermoplastics with excellent chemical resistance and good mechanical properties. Because of their low solubility, few structural characterization studies of PEEK have been reported. In mass spectrometry, only MALDI-TOF analyses for polymer synthesis monitoring have been described with the use of strong acids such as sulfuric acid. This work demonstrates that ASAP is particularly efficient for analysis of PEEK in a solvent free approach with the production of intact small oligomers (n 2). Five types of PEEK oligomers with different end-groups were evidenced. With MALDI-TOF, the same end-groups with almost the same relative abundance were obtained which support the hypothesis that the oligomers detected in ASAP are intact small oligomers and not fragments or pyrolysis products. This is particularly interesting as generally the ASAP analysis of polymers yields pyrolysis products with the loss of end-group information. The end-groups assignments have been confirmed by tandem mass spectrometry (MS/MS) experiments on the M+ molecular ions, which allowed highlighting some specific neutral or radical losses as well as two diagnostic product ions. Thus, ASAP-IM/MS/MS proves to be a fast and efficient alternative way to characterize low solubility polymers such as PEEK

Regio- and Stereo-Specific Chemical Depolymerization of High Molecular Weight Polybutadiene and Polyisoprene for Their Analysis by High Resolution FTICR Mass Spectrometry. Comparison with Py-GCxGC-MS, ASAP&DIP-APCI MS and IMS-MS

Polybutadiene (PB) and Polyisoprene (PI) the two most common polydienes (PD), are involved in a large number of materials and used in a wide variety of applications. The characterization of these polymers by mass spectrometry (MS) continues to be very challenging due to their high insolubility and the difficulty to ionize them. In this work, cross-metathesis reaction was used to generate end-functionalized acetoxy ionizable oligomers for the structural deciphering of different commercial PB and PI samples. A cross-metathesis reaction was carried out between polymers and the Z-1,4-diacetoxy-2-butene as chain transfer agent in dichloromethane using Hoveyda-Grubbs second-generation catalyst. Well-defined acetoxy telechelic structures were obtained and analysed by Fourier-Transform ion cyclotron resonance (FTICR) high resolution MS. However, after depolymerization, low molar mass polyolefins contained some units with different configurations, suggesting an olefin isomerization reaction due to the decomposition of the catalyst. The addition of an electron-deficient reagent such as 2,6-dichloro-1,4-benzoquinone suppressed this isomerization in the case of both Z- and E- PB and PI. Ion-mobility spectrometry-mass spectrometry (IMS-MS) and energy resolved tandem mass spectrometry (ERMS) analyses confirmed a successful isomerization suppression. For comparing the results obtained by depolymerisation with classical methods for polymer analysis, pyrolysis-comprehensive two-dimensional gas chromatography/mass spectrometry (Py-GC×GC-MS), atmospheric solid analysis probe (ASAP) and DIP-APCI analyses were performed on the same polymers. This strategy can be applied on a variety of synthetic and natural not yet characterized polymers

Détermination du chrome dans le cuir: défis de l'extraction et de la spéciation

International audienc