Feasibility study of strain and temperature discrimination in a BOTDA system via artificial neural networks

Automatic discrimination between strain and temperature in a Brillouin optical time domain analyzer via artificial neural networks is proposed and discussed in this paper. Using a standard monomode optical fiber as the sensing element, the ability of the proposed solution to detect the known changes that the Brillouin gain spectrum exhibits depending on the applied temperature and/or strain will be studied. Experimental results, where different simultaneous strain and temperature situations have been considered, will show the feasibility of this technique.This work has been supported by the projects TEC2013-47264-C2-1-R and TEC2016-76021-C2-2-R

Improving of psychological status and inflammatory biomarkers during omalizumab for chronic spontaneous urticaria

Background: Depression and anxiety are the most common psychiatric comorbidities in chronic spontaneous urticaria (CSU). Omalizumab is a monoclonal antibody approved for CSU treatment. We evaluated the prevalence of anxiety and depression in CSU patients before and after treatment with omalizumab. Materials & methods: A total of 30 patients were enrolled in the study: 15 patients affected by CSU and treated with omalizumab and the other 15 healthy subjects did not receive any systemic therapy. All patients were evaluated using Hospital Anxiety and Depression Scale, CRP and erythrocyte sedimentation rate, at baseline and after 6 months. Results: The omalizumab group after 6 months of therapy had a decrease of all the scores and biomarkers. Conclusion: Omalizumab allowed an improvement of urticaria and mental comorbidities

Strain and temperature discrimination in a BOTDA system via Artificial Neural Networks

RESUMEN: En este artículo se propone el uso de un enfoque basado en inteligencia artificial, en particular en redes neuronales artificiales, para conseguir una discriminación automática en medidas de strain y temperatura en sistemas sensores distribuidos basados en la dispersión estimulada de Brillouin en fibra óptica, en particular en implementaciones BOTDA.ABSTRACT: We present in this paper the employment of artificial intelligence, in particular artificial neural networks, as a possible solution to achieve automatic discrimination between strain and temperature measurements in distributed sensor systems based on the stimulated Brillouin scattering in optical fibers, in particular in BOTDA implementations.Este trabajo ha sido cofinanciado por los proyectos TEC2013-47264-C2-1-R and TEC2016-76021-C2-2-R (AEI/FEDER, UE) and CIBERBBN via FEDER funds

Discrimination of strain and temperature in Brillouin Optical Time Domain Analyzers via Artificial Neural Networks

Big structures monitoring is a relevant issue due to their size and trouble to find damages. The goal of this thesis is the achievement of a discrimination between temperature and strain effects occurring on a fiber. The use of distributed OFSs is of big help: the work is based on a BOTDA configuration to retrieve the BGSs along the FUT and use ANNs to analyze them. A maximum of around 70% in some cases for strain and temperature and a unique 86.7% of success for strain selection are reache

Surveillance de structures de stockage de déchets radioactifs : détermination de la convergence de tunnels par mesures réparties de déformations dans des câbles à fibres optiques spécifiques

Dans le cadre du projet Cigéo, stockage géologique des déchets radioactifs à vie longue, la surveillance des infrastructures contribuera à confirmer la récupérabilité des déchets, prévue sur des durées pluridécennales. Les structures sont apparentés à des tunnels horizontaux, sous 500 m de couverture. Leur convergence (réduction progressive de leur section) doit être mesurée par des systèmes peu intrusifs, sensibles, compatibles avec un environnement sévère. Une méthode inverse, utilisant un modèle par éléments finis, a été développée pour déterminer la convergence à partir de mesures réparties de déformations acquises par rétrodiffusion Rayleigh et Brillouin dans des câbles à fibre optique. Elle a été validée sur un démonstrateur d’alvéole, au laboratoire en surface et en souterrain. Sur une échelle de 10 mm représentative de l’application, la convergence est déterminée à 1 mm près par les fibres optiques, proche des capteurs de référence. La sensibilité à la mise en œuvre, au chargement, au bruit de mesure, a été étudiée. La tenue des fibres optiques à l’impact couplé des radiations et de la température a été étudiée pour des fibres optique en revêtement primaire: une dose totale de 1 MGy dégrade moins la mesure de déformation à 100 °C qu’à température ambiante. La fibre optique la plus résistance a été placée dans un câble de mesure de déformations, soumis à des radiations gamma et des sollicitations thermiques. Les coefficients de sensibilité thermique et mécanique des rétrodiffusions Brillouin et Rayleigh restent stables après 500 kGy, ainsi que ses caractéristiques mécaniques du câble. L’étude a aussi permis de quantifier les processus de plasticité, jusqu’à 10000 με.In the framework of Cigéo, the future underground repository for long-lived radioactive waste, the monitoring of the structures must be guaranteed for almost a century to ensure its reversibilit. The horizontal repository cells will be loaded by 500 m of rock which will reduce their section over time. This reduction, called convergence, must be monitored by sensors with resistance to harsh environment, low intrusiveness, proper sensitivity. We propose the use of distributed optical fiber strain sensing cables, whose strain measurements are used to calculate convergence via an inverse-analysis finite-element method, using Brillouin and Rayleigh backscatterings. The method is described, assessing the influence of structural parameters and measurements noise on its sensitivity. We validate it in a laboratory test, in controlled conditions and underground, reproducing convergences up to the representative value of 10 mm on a mock-up of the high-level waste repository cell. We compare two fixation methods and loading schemes, using other sensors as reference. Results show how distributed optical fiber sensors can achieve the required 1 mm of resolution, close to standard methods. The fibers have been firstly analysed under the coupled effect of temperature and radiation up to a total γ-rays dose of 1 MGy. Temperatures around 100°C preserve the fiber functioning better than being at room temperature. A specific cable for strain sensing, with a radiation resistant fiber inside, is then developed and tested, reporting that temperature and strain sensitivities and the mechanical behaviour remain stable up to 500 kGy. We evaluate also the role of the protective layers of the tested cable and its plastic behaviour up to 10000 με