Hydrogeochemical survey of CO2 geological leakage using noble gases: Application to the Furnas Caldera (Azores, Portugual)

Significant natural CO2 emissions have been measured across the caldera of Furnas (São Miguel Island, Azores) allowing us to consider the area as a CO2 leakage analogue. During two field trips, we have collected twenty springs in purpose to measure CO2 contents (Dissolved Inorganic Carbon and "13C) and noble gas isotopic compositions (He and Ne) and for seventeen water samples, major ions chemistry. The corrected 3He/4He ratios (normalized to air ratio RA) range from 1.46 to 5.17, the carbon contents (DIC) range from 0.57 to 41,41 mmol/l and most of the waters have a "13C about -4 ‰. With field observations and waters chemistry, we have characterized seven different types of water springs through the caldera, resulting from various mixing rates between three sources : soil equilibrated meteoritic water, gas emanations (CO2, He…) from a magmatic intrusion and hydrothemal waters coming from a shallow depth aquifer. Saturation indexes and geothermometers indicate a trachytic aquifer at a temperature of about 145°C. In order to confirm that noble gases are good tracers of CO2 leakage, we are building a first mixing model using noble gases and carbon isotopes and a second one based on major ions chemistry with CHESS hydrochemical modelling software. Preliminary mixing models seem to be consistent thus confirming that noble gases can be used as tracors of CO2 leakage

Halogens in Eclogite Facies Minerals from the Western Gneiss Region, Norway

From MDPI via Jisc Publications RouterHistory: accepted 2021-07-08, pub-electronic 2021-07-14Publication status: PublishedFunder: Natural Environment Research Council; Grant(s): NE/L002469/1Ultra-high-pressure (UHP) eclogites and ultramafites and associated fluid inclusions from the Western Gneiss Region, Norwegian Caledonides, have been analysed for F, Cl, Br and I using electron-probe micro-analysis, time-of-flight secondary ion mass spectrometry and neutron-irradiated noble gas mass spectrometry. Textures of multi-phase and fluid inclusions in the cores of silicate grains indicate formation during growth of the host crystal at UHP. Halogens are predominantly hosted by fluid inclusions with a minor component from mineral inclusions such as biotite, phengite, amphibole and apatite. The reconstructed fluid composition contains between 11.3 and 12.1 wt% Cl, 870 and 8900 ppm Br and 6 and 169 ppm I. F/Cl ratios indicate efficient fractionation of F from Cl by hydrous mineral crystallisation. Heavy halogen ratios are higher than modern seawater by up to two orders of magnitude for Br/Cl and up to three orders of magnitude for I/Cl. No correlation exists between Cl and Br or I, while Br and I show good correlation, suggesting that Cl behaved differently to Br and I during subduction. Evolution to higher Br/Cl ratios is similar to trends defined by eclogitic hydration reactions and seawater evaporation, indicating preferential removal of Cl from the fluid during UHP metamorphism. This study, by analogy, offers a field model for an alternative source (continental crust) and mechanism (metasomatism by partial melts or supercritical fluids) by which halogens may be transferred to and stored in the sub-continental lithospheric mantle during transient subduction of a continental margin

Chasing the ‘Killer’ Phonon Mode for the Rational Design of Low Disorder, High Mobility Molecular Semiconductors

Molecular vibrations play a critical role in the charge transport properties of weakly van der Waals bonded organic semiconductors. To understand which specific phonon modes contribute most strongly to the electron – phonon coupling and ensuing thermal energetic disorder in some of the most widely studied high mobility molecular semiconductors, we have combined state-of-the-art quantum mechanical simulations of the vibrational modes and the ensuing electron phonon coupling constants with experimental measurements of the low-frequency vibrations using inelastic neutron scattering and terahertz time-domain spectroscopy. In this way we have been able to identify the long-axis sliding motion as a ‘killer’ phonon mode, which in some molecules contributes more than 80% to the total thermal disorder. Based on this insight, we propose a way to rationalize mobility trends between different materials and derive important molecular design guidelines for new high mobility molecular semiconductors.Royal Society German Research Foundation European Research Council Engineering and Physical Sciences Research Council ARCHER UK National Supercomputing Service Belgian National Fund for Scientific Research Leverhulme Trust Wiener-Anspach Foundation Belgian Walloon Region GENCI-CINES/IDRI

Unraveling unprecedented charge carrier mobility through structure property relationship of four isomers of didodecyl[1]benzothieno[3,2-b][1]benzothiophene

Since the dawn of organic electronics in the 1970’s, academic and industrial research efforts have led to dramatic improvements of the solubility, stability, and electronic properties of organic semiconductors (OSCs).[1, 2] The common benchmark to characterize the electrical performances of OSCs is their charge carrier mobility μ (cm2 V–1 s–1), defined as the drift velocity of the charge carrier (cm s–1) per unit of applied electric field (V cm–1). Reaching high mobilities in OSCs is highly desirable as it allows faster operation of transistors and energy savings by reduced calculation times.[2, 3] However, OSCs performances (conventional values usually range from 1 to 10 cm2 V–1 s–1, with highest values obtained with single-crystal devices mostly exempt of structural defects) are still not comparable to that of state-of-the-art inorganic semiconductors (e.g. metal oxides with µ = 20-50 cm2 V–1 s–1 and polycrystalline silicon with µ > 100 cm2 V–1 s–1) thereby hampering important potential technological applications such as flexible organic light-emitting diode (OLED) displays and wearable electronics.[3, 4

From synthesis to device fabrication: elucidating the structural and electronic properties of C7-BTBT-C7

We report the polymorph investigation, crystallographic study and fabrication of organic field-effect transistors (OFETs) in solution-processed thin films of a prototypical organic semiconductor, i.e., 2,7-diheptylbenzo[b]benzo[4,5]thieno[2,3-d]thiophene (C7-BTBT-C7). We found that this molecule self-assembles solely into one type of stable crystal form, regardless of the experimental conditions employed when using conventional and non-conventional methods of crystallization. The integration of blends of C7-BTBT-C7 with polystyrene as active materials in OFETs fabricated using a solution shearing technique led to a field-effect mobility of 1.42 ± 0.45 cm2 V−1 s−1 in the saturation regime when a coating speed of 10 mm s−1 was employed. The intrinsic structural properties control the overlap of the frontier orbitals, thereby affecting the device performance. The interplay between the crystal packing, thin film morphology and uniformity and its impact on the device performance are reported.We acknowledge the Paul Scherrer Institut, Villigen, Switzerland, for the provision of synchrotron radiation beam time at the beamline MS-X04SA of the SLS (ID proposal 20201790). P. P., L. F., N. M., N. T., J. C., P. S., M. M. T., Y. G., E. M., and L. M., contributors of the paper, are the members of the UHMob project. This work has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant no. 811284. G. S. is a FNRS Research Associate (Belgian National Fund for Scientific Research). G. S. acknowledges financial support from the Francqui Foundation (Francqui Start-Up Grant). G. S. thanks the FNRS for financial support through the research project COHERENCE2 (no. F.4536.23). M. M. T. and L. F. also acknowledge MCIN through the project GENESIS PID2019 and the “Severo Ochoa” Programme for Centers of Excellence in R&D (FUNFUTURE CEX2019-000917-S), and the Generalitat de Catalunya (2017-SGR-918).With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe

Tracing the migration of mantle CO2 in gas fields and mineral water springs in south-east Australia using noble gas and stable isotopes

Geochemical monitoring of CO2 storage requires understanding of both innate and introduced fluids in the crust as well as the subsurface processes that can change the geochemical fingerprint of CO2 during injection, storage and any subsequent migration. Here, we analyse a natural analogue of CO2 storage, migration and leakage to the atmosphere, using noble gas and stable isotopes to constrain the effect of these processes on the geochemical fingerprint of the CO2. We present the most comprehensive evidence to date for mantle-sourced CO2 in south-east Australia, including well gas and CO2-rich mineral spring samples from the Otway Basin and Central Victorian Highlands (CVH). 3He/4He ratios in well gases and CO2 springs range from 1.21 to 3.07 RA and 1.23 – 3.65 RC/RA, respectively. We present chemical fractionation models to explain the observed range of 3He/4He ratios, He, Ne, Ar, Kr, Xe concentrations and δ13C(CO2) values in the springs and the well gases. The variability of 3He/4He in the well gases is controlled by the gas residence time in the reservoir and associated radiogenic 4He accumulation. 3He/4He in CO2 springs decrease 29 away from the main mantle fluid supply conduit. We identify one main pathway for CO2 supply to the surface in the CVH, located near a major fault zone. Solubility fractionation during phase separation is proposed to explain the range in noble gas concentrations and δ13C(CO2) values measured in the mineral spring samples. This process is also responsible for low 3He concentrations and associated high CO2/3He, which are commonly interpreted as evidence for mixing with crustal CO2. The elevated CO2/3He can be explained solely by solubility fractionation without the need to invoke other CO2 sources. The noble gases in the springs and well gases can be traced back to a single end-member which has suffered varying degrees of radiogenic helium accumulation and late stage degassing. This work shows that combined stable and noble gas isotopes in natural gases provide a robust tool for identifying the migration of injected CO2 to the shallow subsurface

Jurisprudence du Tribunal administratif de l'Organisation internationale du Travail

Ruzié David. Jurisprudence du Tribunal administratif de l'Organisation internationale du Travail. In: Annuaire français de droit international, volume 40, 1994. pp. 523-554

Jurisprudence du Tribunal administratif de l'Organisation internationale du travail

Ruzié David. Jurisprudence du Tribunal administratif de l'Organisation internationale du travail. In: Annuaire français de droit international, volume 47, 2001. pp. 401-419

Jurisprudence du Tribunal administratif de l’Organisation internationale du travail

Ruzié David. Jurisprudence du Tribunal administratif de l’Organisation internationale du travail. In: Annuaire français de droit international, volume 54, 2008. pp. 337-362

Le non-renouvellement des contrats à durée déterminée et l'ingérence des Etats. A propos de l'Affaire Ballo

Ruzié David. Le non-renouvellement des contrats à durée déterminée et l'ingérence des Etats. A propos de l'Affaire Ballo. In: Annuaire français de droit international, volume 18, 1972. pp. 378-391