125 research outputs found

    Removal of branched dibenzothiophenes from hydrocarbon mixtures via charge transfer complexes with a TAPA-functionalized adsorbent

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    A process for producing an adsorbent where a metal oxide is reacted with an alkoxy silane to produce an epoxy-functionalized metal oxide. This product is reacted with an amino-substituted propionic acid and a nitro-substituted fluorenone, and this product is grafted to the epoxy-functionalized metal oxide. This grafted product is the adsorbent, which may be contacted with a hydrocarbon mixture having at least one sulfur containing compound in order to remove this sulfur containing compound. Also disclosed is a process for adding polymerization groups to an adsorbent

    Adsorption of dibenzothiophenes from hydrocarbon and model diesel feeds

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    A process for adsorbing aromatic sulfur compounds, where an adsorbent is contacted with a C.sub.6-C.sub.20 aromatic and/or aliphatic stream which comprises a solution of (i) at least one benzothiophene compound, (ii) a solvent which comprises at least one C.sub.6-C.sub.16 aliphatic compound, and (iii) optionally at least one C.sub.6-C.sub.12 aromatic compound. In this process, the adsorbent is regenerated using an organic regenerant such as, but not limited to, toluene. Also disclosed is another process for adsorbing aromatic sulfur compounds. In this process, an adsorbent is contacted with a mixture comprising a model diesel feed comprising at least one benzothiophene compound. In this process, the adsorbent is regenerated using an organic regenerant such as, but not limited to, toluene

    Energy measurement of fast neutron fields with a Recoil Proton Telescope using active pixel sensors

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    The spectrometer ATHENA (Accurate Telescope for High Energy Neutron metrology Applications), in development at the LNE-IRSN, characterizes energy and fluence of fast neutron fields. The detector is a Recoil Proton Telescope and measures neutron energies in the range of 5 to 20 MeV. The system is intended to become a primary standard for both energy and fluence measurements. The most innovative part of ATHENA is made of three CMOS pixel sensors, thinned down to 50 microns thickness, allowing an accurate tracking of the recoil. The use of CMOS sensors and a thick silicon diode increase the intrinsic efficiency of the detector by a factor of ten compared with conventional designs. In this paper, we demonstrate the ability of the detector to measure neutron energies in the range of 5 to 20 MeV. Experimental investigations, using mono-energetic neutron fields produced by the AMANDE facility, indicate a good reconstruction of neutron energies. The present design is still under development. The accuracy of measuring 5 MeV and 14 MeV neutron energies was 15% and 5%, respectively

    First report of Brenneria goodwinii, Gibbsiella quercinecans and Rahnella victoriana in declining oaks in France

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    Acute Oak Decline, Quercus petraea, Quercus robur Acute Oak Decline (AOD) is mediated by abiotic factors (temperature and precipitation) and triggered by insects (mainly the bark-boring beetle Agrilus biguttatus) and a complex of bacterial species (mainly Bren-neria goodwinii, Gibbsiella quercinecans and Rahnella victoriana) (Denman et al., 2017; Doonan et al., 2020). Given the extent of oak dieback and the prevalence of A. biguttatus in France (Saintonge & Goudet, 2020; Sallé et al., 2022), a preliminary study was done in five French forests to assess the prevalence of AOD symptoms (bleeding cortical lesions on the trunk associated with insect emergence holes and dieback) and to determine the bacteria associated with those symptoms. The mean prevalence of AOD symptoms was estimated at 37% arround 20 trees assessed in each of the five forests. Bark samples and, when possible, exudates were taken from lesions associated with insect emergence holes and/or cracks (Fig. 1). Bacterial isolations were made from 43 bark samples and 11 exudate samples by plating on three agar media (Luria, Gifu Anaerobic and Eosin Methylene Blue) and incubated at 22 • C for one to five days. Bacterial strains were identified by high-resolution melting (Brady et al., 2016) or 16S rRNA sequencing (Denman et al., 2016). The sequenced strains had 100% identity with sequences of reference strains (GenBank Accession Nos. CP014137.1, CP014136.1 and NR_146847.1). The percentage of trees infected with G. quercinecans, B. goodwinii and R. victoriana was 21, 16 and 12, respectively. These AOD-associated bacteria were detected with a higher success rate in exudates (81%) than in bark (25%). Gibbsiella quercinecans and B. good-This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited

    Molecular excitation in the Interstellar Medium: recent advances in collisional, radiative and chemical processes

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    We review the different excitation processes in the interstellar mediumComment: Accepted in Chem. Re

    The water vapour continuum in near-infrared windows – current understanding and prospects for its inclusion in spectroscopic databases

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    Spectroscopic catalogues, such as GEISA and HITRAN, do not yet include information on the water vapour continuum that pervades visible, infrared and microwave spectral regions. This is partly because, in some spectral regions, there are rather few laboratory measurements in conditions close to those in the Earth’s atmosphere; hence understanding of the characteristics of the continuum absorption is still emerging. This is particularly so in the near-infrared and visible, where there has been renewed interest and activity in recent years. In this paper we present a critical review focusing on recent laboratory measurements in two near-infrared window regions (centred on 4700 and 6300 cm−1) and include reference to the window centred on 2600 cm−1 where more measurements have been reported. The rather few available measurements, have used Fourier transform spectroscopy (FTS), cavity ring down spectroscopy, optical-feedback – cavity enhanced laser spectroscopy and, in very narrow regions, calorimetric interferometry. These systems have different advantages and disadvantages. Fourier Transform Spectroscopy can measure the continuum across both these and neighbouring windows; by contrast, the cavity laser techniques are limited to fewer wavenumbers, but have a much higher inherent sensitivity. The available results present a diverse view of the characteristics of continuum absorption, with differences in continuum strength exceeding a factor of 10 in the cores of these windows. In individual windows, the temperature dependence of the water vapour self-continuum differs significantly in the few sets of measurements that allow an analysis. The available data also indicate that the temperature dependence differs significantly between different near-infrared windows. These pioneering measurements provide an impetus for further measurements. Improvements and/or extensions in existing techniques would aid progress to a full characterisation of the continuum – as an example, we report pilot measurements of the water vapour self-continuum using a supercontinuum laser source coupled to an FTS. Such improvements, as well as additional measurements and analyses in other laboratories, would enable the inclusion of the water vapour continuum in future spectroscopic databases, and therefore allow for a more reliable forward modelling of the radiative properties of the atmosphere. It would also allow a more confident assessment of different theoretical descriptions of the underlying cause or causes of continuum absorption
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