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61.
Sandra Barbouteau Patrick Rasolofosaon Noalwenn Dubos‐Sallée Virginie Vassil Jean‐François Nauroy 《Geophysical Prospecting》2017,65(1):240-250
An alternative laboratory technique to measure the elastic constants of solid samples, based on the analysis of the cross‐correlation spectra of the vibratory response of randomly excited short solid cylinders, has been recently proposed. The aim of this paper is to check the ability of the technique called passive ultrasonic interferometry to monitor fluid substitution in different rock samples. Velocity variations due to fluid substitution are easily measured if the wave attenuation in the fluid‐saturated rock is not too large (typically in rocks with few cracks or microfractures). The experimental results are in agreement with the predictions of Biot–Gassmann poroelastic theory. The effect of substituting water with a stiffer saturating fluid, such as ethylene glycol, is to increase the overall bulk modulus of the rock, without any substantial effect on shear modulus. Furthermore, the experimental results compare well with those obtained independently with conventional pulse‐transmission technique using ultrasonic transducers. However, the measured pulse‐transmission bulk moduli are slightly larger than the corresponding measured ultrasonic interferometry moduli, with the deviation increasing with increasing fluid viscosity. This can be explained by dispersion due to wave‐induced flow of the viscous fluid since pulse‐transmission experiments involve higher frequencies than ultrasonic interferometry experiments. 相似文献
62.
Virginie Mamadouh 《GeoJournal》1999,48(2):133-144
The linguistic diversity in the European Union is generally viewed as an essential component of the European identity, but the linguistic regime of the EU institutions (with eleven official and working languages) is not undisputed. In addition, the upcoming enlargements will complicate greatly the continuation of the present practices as new Member States bring new official languages. As a result, the debate about possible reforms is likely to be boosted by the necessity to prepare EU institutions for further enlargment. The present regime of institutional multilingualism is criticised from different angles, resulting in three options for the future. In this paper the linguistic regime of EU institutions is discussed in relation to general ideas about the nature of this supranational political system. Supranationalism is treated here as a program to supersede nationalism. Three variants are distinguished: pacified nationalism, neo-nationalism and post-nationalism. The paper examines how these different visions of Europe shed different lights on the issue of multilingualism (in terms of communication, identity and power) and its institutionalisation in the linguistic regime of the core instituions of the European Union. Although the three models are compatible with several arrangements, they support or oppose them for different reasons. Besides, they differ regarding the significance of the linguistic regime of the EU institutions for the whole polity and their ability to steer linguistic practices. 相似文献
63.
Grid-group cultural theory: an introduction 总被引：2，自引：0，他引：2
Virginie Mamadouh 《GeoJournal》1999,47(3):395-409
This article offers an introduction to grid-group cultural theory (also known as grid-group analysis, Cultural Theory or theory
of socio-cultural viability), an approach that has been developed over the past thirty years in the work of the British anthropologists
Mary Douglas and Michael Thompson, the American political scientist Aaron Wildavsky, and many others. This assessment begins
with a presentation of the main claims of the theory, distinguishing two characteristic breads of grid-group cultural theory,
in the one it is conceived as a heuristic device, in the other it is seen as a full explanatory theory. This brief is followed
by a discussion of the typology generated by the theory. This includes a presentation of the two dimensions of sociality it
posits, the cultural map they produce, as well as the four (or five) cultural types derived from them and their designations.
The article proceeds with a discussion of key issues including the incorporation of other typologies (such as the one developed
to analyse myths of nature), the relations between cultures or rationalities and several methodological issues. Finally the
article introduces the contributions to this special issue of the GeoJournal.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
64.
65.
This article offers an analysis of the emerging scalar configuration of the governance of the European Union. It discusses how European integration stands for a move from a collection of territorially homogenous systems of rule towards a new assemblage of territories, authorities and rights. The paper first questions the stretchy territoriality of the seemingly obvious European level. Second it analyses the sectoral differences in the evolution of the width and the depth of integration, measured as the transfer of competencies to the EU level between the Rome Treaty (1958) and the Lisbon Treaty (200y). Third it turns to the day-to-day decision-making to assess the relations between players in EU governance and finally it looks more closely at the administrative wheels of the EU machinery. 相似文献
66.
Georges Durry Alain Hauchecorne Joelle Ovarlez Henri Ovarlez Ivan Pouchet Virginie Zeninari Bertrand Parvitte 《Journal of Atmospheric Chemistry》2002,43(3):175-194
Telecommunication laser diodes emitting near 1.39 m and 1.65 m in combination with direct-differential absorption spectroscopy are efficient tools to monitor in situ stratospheric H2O andCH4 with a good precision error (a few percents), a high temporal resolution (ranging from 10 ms to 1 s), a large dynamic range in the concentration measurements (four orders of magnitude) and a high selectivity in the analyte species. To illustrate the capability of laser probing technique, we report balloonborne H2Oand CH4 simultaneous measurements obtained on October 2001 atmidlatitudes (43° N). The H2O vertical profile achieved with the lasersensor in the lower stratosphere is compared with the H2O data yielded by a balloonborne frost-point hygrometer. The total hydrogen mixing ratio in the lower stratosphere, 2[CH4] + [H2O], appears to beconstant at 7.5 ± 0.1 ppmv. Nevertheless, an unexpected largedehydration of 0.5 ppmv was detected by both the laser sensor and thehygrometer between 16 km and 23 km. We suspect the occurrence of a tropicalair intrusion into mid-latitudes. We support this interpretation using a high-resolution advection model for potential vorticity. 相似文献
67.
Stable SO4 isotopes (δ34S-SO4 and δ18O-SO4), and more occasionally δ15N-NO3 were studied in groundwater from seven hard-rock aquifer catchments. The sites are located in Brittany (France) and all are characterized by intensive agricultural activity. The purpose of the study was to investigate the potential use of these isotopes for highlighting the fate of both SO4 and NO3 in the different aquifer compartments. Nitrate-contaminated groundwater occurs in the regolith; δ34S fingerprints the origin of SO4, such as atmospheric deposition and fertilizers, and δ18O-SO4 provides evidence of the cycling of S within soil. The correlation between the δ18O-SO4 of sulfates and the δ15N-NO3 of nitrates suggests that S and N were both cycled in soil before being leached to groundwater. Autotrophic and heterotrophic denitrification was noted in fissured aquifers and in wetlands, respectively, the two processes being distinguished on the basis of stable SO4 isotopes. During autotrophic denitrification, both δ34S-SO4 and δ18O-SO4 decrease due to the oxidation of pyrite and the incorporation of O from the NO3 molecule in the newly formed SO4. Within wetlands, fractionation occurs of O isotopes on SO4 in favour of lighter isotopes, probably through reductive assimilation processes. Fractionation of S isotopes is negligible as the redox conditions are not sufficiently reductive for dissimilatory reduction. δ34S-SO4 and δ18O-SO4 data fingerprint the presence of a NO3-free brackish groundwater in the deepest parts of the aquifer. Through mixing with present-day denitrified groundwater, this brackish groundwater can contribute to significantly increase the salinity of pumped water from the fissured aquifer. 相似文献