Éditeur(s) : HAL CCSD
Résumé : International audience
A fiber interferometer interfaced to 3 geo-mechanical elements is presented for applications in geophysics. The fiber sensor is based on an extrinsic fiber Fabry-Perot interferometer (EFFPI) which incorporates a modulation scheme to lock the interferometer at quadrature and to enable displacement measurements below a quarter of the interrogating wavelength. It operates over a relatively large frequency dynamic of ~500000 with a precision better than 2 nm. The fiber interferometer is next interfaced to a differential hydrostatic long baseline inclinometer, a 3-axis borehole tiltmeter and a single-axis seismometer, respectively. Results obtained demonstrate that the fiber interferometrically-interrogated instruments exhibit performances equivalent to or even surpassing those of the reference instruments employed for comparison during their deployment to an underground test site since March 2012. Keywords—modulation-based extrinsic fiber Fabry-Perot interferometer; fiber optique hydrostatic inclinometer; fiber optique borehole tiltmeter; fiber optique seismometer
IEEE SENSORS 2015
Busan, South Korea

hal-01265963
https://hal.archives-ouvertes.fr/hal-01265963
https://hal.archives-ouvertes.fr/hal-01265963/document
https://hal.archives-ouvertes.fr/hal-01265963/file/HCS3.pdf
DOI : 10.1109/ICSENS.2015.7370316

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The prognosis of vertebral alveolar echinococcosis (AE) is poor. We report on the unique outcome of a patient with preexisting liver cirrhosis, in whom a diagnosis of vertebral AE was established on vertebral histopathology (D4 corporectomy in 2010 for paraplegia). Therapeutic drug monitoring of albendazole (ABZ) showed that a low dosage was appropriate. The patient recovered and ABZ withdrawal was decided in 2014, with no relapse 18 months later. In this patient, infection was purely or mainly localized in the dorsal spine, and this may have been favored by liver cirrhosis. A longer follow-up is, however, needed to confirm cure.
ISSN: 0300-8126

hal-01509561
https://hal.archives-ouvertes.fr/hal-01509561
PUBMED : 28004258

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
ISSN: 0956-540X

hal-01187132
https://hal.archives-ouvertes.fr/hal-01187132

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Sensitive instruments like strainmeters and tiltmeters are necessary for measuring slowly varying low amplitude Earth deformations. Nonetheless, laser and fibre interferometers are particularly suitable for interrogating such instruments due to their extreme precision and accuracy. In this paper, a practical design of a simple pendulum borehole tiltmeter based on laser fibre interferometric displacement sensors is presented. A prototype instrument has been constructed using welded borosilicate with a pendulum length of 0.85 m resulting in a main resonance frequency of 0.6 Hz. By implementing three coplanar extrinsic fibre Fabry-Perot in-terferometric probes and appropriate signal filtering, our instrument provides tilt measurements that are insensitive to parasitic deformations caused by temperature and pressure variations. This prototype has been installed in an underground facility (Rustrel, France) where results show accurate measurements of Earth strains derived from Earth and ocean tides, local hydro-logic effects, as well as local and remote earthquakes. The large dynamic range and the high sensitivity of this tiltmeter render it an invaluable tool for numerous geophysical applications such as transient fault motion, volcanic strain and reservoir monitoring.
ISSN: 0956-540X

hal-01265967
https://hal.archives-ouvertes.fr/hal-01265967
https://hal.archives-ouvertes.fr/hal-01265967/document
https://hal.archives-ouvertes.fr/hal-01265967/file/HCS1.pdf
DOI : 10.1093/gji/ggv358