Search results for "Infrarouge"
showing 10 items of 36 documents
The Indian-French Trishna Mission: Earth Observation in the Thermal Infrared with High Spatio-Temporal Resolution
2018
International audience; The monitoring of the water cycle at the Earth surface which tightly interacts with the climate change processes as well as a number of practical applications (agriculture, soil and water quality assessment, irrigation and water resource management, etc...) requires surface temperature measurements at local scale. Such is the goal of the Indian-French high spatio-temporal TRISHNA mission (Thermal infraRed Imaging Satellite for High-resolution Natural resource Assessment). The scientific objectives of the mission and research work conducted to consolidate the mission specifications are presented. Progress in modelling of surface fluxes is then discussed. The main spec…
Contribution to the study and to the optimization of active thermographic process applied to surface crack detection
2017
The aim of this work is the detection of open and subjacent defects in metallic materials using laser-material interaction coupled with infrared thermography. This process is a possible alternative for magnetic particles testing and dye penetrant testing in the field of non-destructive testing. This work is divided into three main parties. At first, we have been interested in the characterization of optical and thermophysical properties of materials we used, in order to have good boundary conditions and also for the needs of temperatures fields measurements for validation. The second part concern the development of a numerical simulation model with two step approach: the first involves mode…
Determination of fatty acids and lipid classes in salmon oil by near infrared spectroscopy
2017
International audience; Near-infrared (NIR) spectroscopy was evaluated as a rapid method for the determination of oleic, palmitic, linoleic and linolenic acids as well as omega-3, omega-6, and to predict polyunsaturated, monounsaturated and saturated fatty acids, together with triacylglycerides, diglycerides, free fatty acids and ergosterol in salmon oil. To do it, Partial Least Squares (PLS) regression models were applied to correlate NIR spectra with aforementioned fatty acids and lipid classes. Results obtained were validated in front of reference procedures based on high performance thin layer and gas chromatography. PLS-NIR has a good predictive capability with relative root mean squar…
Simulation de spectres à haute température : une approche statistique du compromis résolution / précision
2010
International audience; Malgré les progrès continus enregistrés dans le domaine de la spectroscopie moléculaire, théorique et expérimentale, les banques de données spectroscopiques disponibles présentent des lacunes importantes, notamment pour l'interprétation des observations des environnements astrophysiques à haute température. Ce constat s'applique en particulier à la molécule de méthane présente dans les atmosphères de nombreux objets astrophysiques. La modélisation du coefficient d'absorption du méthane dans le proche infrarouge et/ou à haute température continue à défier les théoriciens du fait de la complexité intrinsèque de son spectre rovibrationnel. De fait, les analyses à haute …
Gas chromatography / Infrared spectroscopy
2000
International audience
Study of new tellurite glasses in the TeO2-ZnO-La2O3 (TZL) system for the manufacturing of mid-infrared multimaterial optical fibers and specialty op…
2023
This thesis work was carried out using tellurite glasses from the TeO2-ZnO-La2O3 (TZL) ternary diagram for optical fibers manufacturing. The choice to use this system is motivated by the ambition to improve the transmission of optical signals within oxide glasses for which absorption bands related to OH groups are present in the transparency window. A structural study is first carried out on these glasses by Raman spectroscopy in order to understand the influence of the composition on physicochemical properties (especially on optical and thermal properties) but also to estimate the ability of a vitreous matrix to reorganize when subjected to a thermal solicitation such as the preform-to-fib…
Small-core chalcogenide microstructured fibers for the infrared.
2008
International audience; We report several small-core chalcogenide microstructured fibers fabricated by the "Stack & Draw" technique from Ge(15)Sb(20)S(65) glass with regular profiles. Mode field diameters and losses have been measured at 1.55 microm. For one of the presented fibers, the pitch is 2.5 microm, three times smaller than that already obtained in our previous work, and the corresponding mode field diameter is now as small as 3.5 microm. This fiber, obtained using a two step "Stack & Draw" technique, is single-mode at 1.55 microm from a practical point of view. We also report the first measurement of the attenuation between 1 and 3.5 microm of a chalcogenide microstructured fiber. …
Supercontinuum generation in chalcogenide: application to gas spectroscopy in atmospheric band III
2023
This thesis work aims to contribute to the development of new fiber sources emitting over a wide range of wavelengths in the IR, in particular to detect greenhouse gases in the mid-infrared range. Our spectroscopy results with nitrous oxide N2O and methane CH4 are obtained in band III. To achieve this, the generation of supercontinuum (SC) covering band III was made possible by using chalcogenide optical fibers, purified and free of highly toxic elements according to REACH regulations, in particular arsenic and antimony. The fibrable vitreous composition belonging to the Ge-Se-Te ternary system fits perfectly into the context of sustainable development, it is the one that has been identifie…
Measurement of interaction between aroma compounds and the protein beta-lactoglobulin by spectroscopic methods
1999
International audience
Supercontinuum generation in chalcogenides : application to gas spectroscopy in atmospheric band III
2023
This thesis work aims to contribute to the development of new fiber sources emitting over a wide range of wavelengths in the IR, in particular to detect greenhouse gases in the mid-infrared range. Our spectroscopy results with nitrous oxide N2O and methane CH4 are obtained in band III. To achieve this, the generation of supercontinuum (SC) covering band III was made possible by using chalcogenide optical fibers, purified and free of highly toxic elements according to REACH regulations, in particular arsenic and antimony. The fibrable vitreous composition belonging to the Ge-Se-Te ternary system fits perfectly into the context of sustainable development, it is the one that has been identifie…