Biofouling protection for marine environmental sensors

These days, many marine autonomous environment monitoring networks are set up in the world. These systems take advantage of existing superstructures such as offshore platforms, lightships, piers, breakwaters or are placed on specially designed buoys or underwater oceanographic structures. These systems commonly use various sensors to measure parameters such as dissolved oxygen, turbidity, conductivity, pH or fluorescence. Emphasis has to be put on the long term quality of measurements, yet sensors may face very short-term biofouling effects. Biofouling can disrupt the quality of the measurements, sometimes in less than a week. <br><br> Many techniques to prevent biofouling on instrumentation are listed and studied by researchers and manufacturers. Very few of them are implemented on instruments and of those very few have been tested in situ on oceanographic sensors for deployment of at least one or two months. <br><br> This paper presents a review of techniques used to protect against biofouling of in situ sensors and gives a short list and description of promising techniques

Mineral phase analysis of deep-sea hydrothermal particulates by a Raman spectroscopy expert algorithm : toward autonomous in situ experimentation and exploration

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 10 (2009): Q05T05, doi:10.1029/2008GC002314.This paper demonstrates that a Raman spectroscopy, point-counting technique can be used for phase analysis of minerals commonly found in deep-sea hydrothermal plumes, even for minerals with similar chemical compositions. It also presents our robust autonomous identification algorithm and spectral database, both of which were developed specifically for deep-sea hydrothermal studies. The Raman spectroscopy expert algorithm was developed and tested against multicomponent mixtures of minerals relevant to the deep-sea hydrothermal environment. It is intended for autonomous classification where many spectra must be examined with little or no human involvement to increase analytic precision, accuracy, and data volume or to enable in situ measurements and experimentation.Support for J.A.B. was provided through a RIDGE 2000 Postdoctoral Fellowship (NSF OCE-0550331)

Réflexions sur les moyens de rendre la médecine une science certaine et positive / par Michel Lehaitre,...

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Surface plasmon resonance in chalcogenide glass-based optical system

International audienceThe surface plasmon resonance phenomenon has been studied in a chalcogenide glass-based optical system. IR transmission properties of these materials combined to their high refractive indices lead to advantageous properties for sensing. In this study, numerical simulations have been carried out to investigate the potentialities of sulfide glass from the GeGaSbS system as a coupling prism material. Then, an angular modulation SPR biosensor has been set up in the Kretschmann-Raether arrangement. Experimental data are consistent with numerical calculation and the detection limit of the sensor is 3 × 10−5 RIU. These preliminary results are promising. Further investigations have to be carried out to confirm the great potentialities of those materials for SPR-based biosensor

Capteurs bio-chimiques Groupe I : capteurs chimiques a fibres optiques

Etude recouvrant les subventions 91-B-0270 a 91-B-0279 inclusesAvailable at INIST (FR), Document Supply Service, under shelf-number : AR 15533 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

Chalcogenide waveguide for IR optical range

International audienceDue to remarkable properties of the chalcogenide glasses, especially sulphide glasses, amorphous chalcogenide films should play a motivating role in the development of integrated planar optical circuits and their components. This paper describes the fabrication and properties of optical waveguides of pure and rare earth doped sulphide glass films prepared by two complementary techniques: RF magnetron sputtering and pulsed laser deposition (PLD). The deposition parameters were adjusted to obtain, from sulphide glass targets with a careful control of their purity, layers with appropriate compositional, morphological, structural characteristics and optical properties. These films have been characterized by micro-Raman spectroscopy, atomic force microscopy (AFM), X-ray diffraction technique (XRD) and scanning electron microscopy (SEM) coupled with energy dispersive X-ray measurements (EDX). Their optical properties were measured thanks to m-lines prism coupling and near field methods. Rib waveguides were produced by dry etching under CF4, CHF3 and SF6 atmosphere. The photo-luminescence of rare earth doped GeGaSbS films were clearly observed in the n-IR spectral domain and the study of their decay lifetime will be presented. First tests were carried out to functionalise the films with the aim of using them as sensor