Numerical modelling of the Vaugris reservoir on the Rhône with Telemac 3D

Water Qualit

Towards truly simultaneous PIXE and RBS analysis of layered objects in cultural heritage

For a long time, RBS and PIXE techniques have been used in the field of cultural heritage. Although the complementarity of both techniques has long been acknowledged, its full potential has not been yet developed due to the lack of general purpose software tools for analysing the data from both techniques in a coherent way. In this work we provide an example of how the recent addition of PIXE to the set of techniques supported by the DataFurnace code can significantly change this situation. We present a case in which a non homogeneous sample (an oxidized metal from a photographic plate -heliography- made by Niepce in 1827) is analysed using RBS and PIXE in a straightforward and powerful way that can only be performed with a code that treats both techniques simultaneously as a part of one single and coherent analysis. The optimization capabilities of DataFurnace, allowed us to obtain the composition profiles for these samples in a very simple way.Comment: 9 pages, 3 figure

Etude physico-chimique des vernis d'un corpus d'instruments de musique européens du 15e au 18e siècle (approche historique et perspectives de conservation)

Diverses hypothèses, souvent contradictoires, ont été émises sur la composition des vernis anciens d instruments de musique, comme ceux d'Antonio Stradivari, et ce depuis plus d'un siècle. Ni ces hypothèses ni les quelques résultats expérimentaux apportés ne permettent aujourd'hui de bien appréhender les processus de vernissage suivis par les luthiers jusqu'à la fin du 18e siècle en Europe. L objectif de cette thèse est de confronter les informations rassemblées dans les sources historiques à l analyse d un certain nombre de vernis d instruments d époque grâce à une méthodologie analytique spécifique. L'étude des sources écrites et iconographiques montre qu'une compréhension globale et cohérente du sujet n'est pas possible sur la base de ces seuls éléments. Puis, une méthodologie ordonnant et optimisant les méthodes d'analyse physico-chimique est élaborée pour caractériser des vernis anciens d'instruments de musique. Elle privilégie les analyses in situ et non destructives, et lorsqu un micro-prélèvement est possible, l analyse de celui-ci est optimisée. Ainsi les techniques spectroscopiques (EDXRF, fluorimétrie), de micro-spectrométrie vibrationnelle (IRTF/synchrotron, Raman), d'analyses séparatives (GC/MS, Py-GC/MS) et d'imagerie (MEB/EDX, OCT) ont été appliquées à des vernis issus d un corpus de soixante-dix instruments de collections patrimoniales européennes, en premier lieu celle du Musée de la musique de Paris. Les résultats obtenus portent à la fois sur la structure stratigraphique et sur la composition chimique, organique et inorganique, de chacune des strates identifiées dans le vernis. Ces résultats contribuent à apporter des éléments inédits sur l'histoire des techniques de vernissage et permettent d aborder sous un angle nouveau les questions liées à la conservation de ces instruments de musique vernis et de toutes les valeurs qui y sont attachées.Various, and often contradictory, hypotheses have been raised for more than a century concerning the composition of ancient varnishes of musical instruments, in particular those made by Antonio Stradivari. Neither these hypotheses, nor the rare experimental results, allow grasping correctly the varnishing processes used by European instrument-makers until the end of the 18th century. The aim of this PhD work is to confront information collected in historical sources with the analysis of a group of instruments varnishes using a specific analytical methodology. First, the study of written and iconographical documents shows that a general and coherent understanding of this topic is not achievable on the basis of these sole elements. Then, a methodology organizing and optimizing chemical analytical methods is elaborated to characterize ancient varnishes of musical instruments. It prioritizes in situ and non destructive analyses, and, when micro-sampling is possible, its analysis is optimized. Thus, techniques as spectroscopies (EDXRF, fluorimetry), micro-spectrometries (FTIR/synchrotron, Raman), separative analyses (GC/MS, Py-GC/MS) and imaging techniques (SEM/EDX, OCT) have been applied to varnishes of a corpus of seventy instruments from European collections, mainly the one in Musée de la musique, Paris. Results deal both with the stratigraphy and the chemical organic and inorganic composition of each of the identified strata. These results bring novel insights to the history of varnishing techniques and suggest new approaches to the conservation of these varnished musical instruments and of all their values.PARIS-Museum Hist.Naturelle (751052304) / SudocSudocFranceF

In Operando Spectroscopic Ellipsometry Investigation of MOF Thin Films for the Selective Capture of Acetic Acid

International audienceThe emission of polar volatile organic compounds (VOCs) is a major worldwide concern of air quality and equally impacts the preservation of cultural heritage (CH). The challenge is to design highly efficient adsorbents able to selectively capture traces of VOCs such as acetic acid (AA) in the presence of relative humidity (RH) normally found at storage in museums (40-80%). Although the selective capture of VOCs over water is still challenging, Metal-Organic Frameworks (MOFs) possess highly tunable features (Lewis, Bronsted or redox metal sites, functional groups, hydrophobicity…) suitable to selectively capture a large variety of VOCs. In this context, we have explored the adsorption efficiency of a series of MOFs thin films (ZIF-8(Zn), MIL-101(Cr) and UiO-66(Zr)-2CF3) for the selective capture of AA based on a UV/Vis and FT-IR spectroscopic ellip-sometry in operando study (2-6% of relative pressure of AA under 40% of RH), namely conditions close to the realistic envi-ronmental storage conditions of cultural artefacts. For that purpose, optical quality thin films of MOFs were prepared by dip-coating and their AA adsorption capacity and selectivity were evaluated under humid conditions by measuring the variation of the refractive index as a function of the vapor pressures while the chemical nature of the co-adsorbed analytes (water and AA) was identified by FT-IR ellipsometry. While thin films of ZIF-8(Zn) strongly degraded when exposed to AA/water va-pors, films of MIL-101(Cr) and UiO-66(Zr)-2CF3 present a high chemical stability under those conditions. It was shown that MIL-101(Cr) presents a high AA adsorption capacity due to its high pore volume, but exhibits a poor AA adsorption selectivi-ty under humid conditions. In contrast, UiO-66(Zr)-2CF3 was shown to overpass MIL-101(Cr) in terms of AA/ H2O adsorp-tion selectivity and AA adsorption/desorption cycling stability thanks to its high hydrophobic character, suitable pore size for adequate confinement and specific interactions

In Operando Spectroscopic Ellipsometry Investigation of MOF Thin Films for the Selective Capture of Acetic Acid

International audienceThe emission of polar volatile organic compounds (VOCs) is a major worldwide concern of air quality and equally impacts the preservation of cultural heritage (CH). The challenge is to design highly efficient adsorbents able to selectively capture traces of VOCs such as acetic acid (AA) in the presence of relative humidity (RH) normally found at storage in museums (40-80%). Although the selective capture of VOCs over water is still challenging, Metal-Organic Frameworks (MOFs) possess highly tunable features (Lewis, Bronsted or redox metal sites, functional groups, hydrophobicity…) suitable to selectively capture a large variety of VOCs. In this context, we have explored the adsorption efficiency of a series of MOFs thin films (ZIF-8(Zn), MIL-101(Cr) and UiO-66(Zr)-2CF3) for the selective capture of AA based on a UV/Vis and FT-IR spectroscopic ellip-sometry in operando study (2-6% of relative pressure of AA under 40% of RH), namely conditions close to the realistic envi-ronmental storage conditions of cultural artefacts. For that purpose, optical quality thin films of MOFs were prepared by dip-coating and their AA adsorption capacity and selectivity were evaluated under humid conditions by measuring the variation of the refractive index as a function of the vapor pressures while the chemical nature of the co-adsorbed analytes (water and AA) was identified by FT-IR ellipsometry. While thin films of ZIF-8(Zn) strongly degraded when exposed to AA/water va-pors, films of MIL-101(Cr) and UiO-66(Zr)-2CF3 present a high chemical stability under those conditions. It was shown that MIL-101(Cr) presents a high AA adsorption capacity due to its high pore volume, but exhibits a poor AA adsorption selectivi-ty under humid conditions. In contrast, UiO-66(Zr)-2CF3 was shown to overpass MIL-101(Cr) in terms of AA/ H2O adsorp-tion selectivity and AA adsorption/desorption cycling stability thanks to its high hydrophobic character, suitable pore size for adequate confinement and specific interactions

Diversité de l’élevage en Auvergne : un levier de durabilité pour la transition agroécologique

Les Brèves 2016 / PSDR new-DEAL