On line infrared measurements in food processing

National audienc

Méthodes infrarouges à filtres, à transformée de Fourier et aérométriques pour contrôler les fermentations alcooliques des virus

International audienceAreometry, filter near infrared spectrometry (FIR), and Fourier transform near infrared spectrometry (FTIR), have been compared for following total sugar and ethanol during fermentations. Standard errors of calibration(SEC) and prediction (SEP) have been estimated, respectively, with 4 and 2 fermentations, using as reference sugar and ethanol enzymatic analysis. With the first 4 fermentations, the least rectangles method was applied for a more thorough comparison between FIR, FTIR, and areometry. FIR was more complex and more accurate than density measurement, and less complex, but as accurate as FTIR spectrometry. Small SEP can be achieved with FIR spectrometry : 2,5g/L for total sugars and 0.15% (v/v) for ethanol.L'aérométrie, la spectrométrie infrarouge à filtres (FIR) et à transformée de Fourier (FTIR) ont été comparées pour suivre les concentrations en sucres totaux et en éthanol au cours de fermentations de moûts de raisin. Les erreurs standards de calibration (SEC) et de prédiction (SEP) ont été estimées, respectivement, avec 4 et 2 fermentations, en utilisant une méthode enzymatique de dosage des sucres et de l'alcool comme référence. Pour les quatre premières fermentations une méthode d'ajustement des moindres rectangles était appliquée pour comparer les méthodes FIR FTIR entre elles. FIR était plus complexe et plus précise que la simple mesure de densité, mais moins complexe et aussi précise que la spectrométrie à transformée de Fourier. Une faible erreur standard de prédiction était obtenue avec la spectrométrie FIR : 2.5g/L pour les sucres totaux et 0.15% (V/V) pour l'éthanol

Non destructive fruit control : sugar content by near-infrared reflectance

International audienc

Optical behavior of silver nanoparticles embedded in polymer thin film layers

Conference on Nanostructured Thin Films IX, San Diego, CA, AUG 30-SEP 01, 2016International audienceThe study of metal nanoparticles (NPs) is challenging for the control of the light matter interaction phenomena. In this context, our work is focused on optical characterization and modeling of polymer thin films layers with inclusions of previously chemically synthesized NPs. Through the presence of metallic NPs in polymer thin films, the optical properties are assumed to become tunable. Thin film layers with inclusions of differently shaped and sized silver NPs, such as nanospheres and nanoprisms, are optically characterized to get the scattering, the reflection and the absorption of the layers. One step and two step seed based methods of silver ions reduction are used for the chemical synthesis of nanospheres and nanoprisms. The plasmonic resonance peaks of these colloidal solutions range from 360 to 1300 nm. A poly vinyl pyrrolidone (PVP) polymer matrix is chosen for its light non-absorbing and NP-stabilizing properties. Knowledge on the shape and size of the NPs embedded in the spin coated layers is obtained by transmission electron microscopy (TEM) imaging. The optical properties include spectrophotometry and spectroscopic ellipsometry (SE) measurements to get the reflectance, the transmittance, the absorptance and the optical indices n and k of the heterogeneous layers. A redshift in absorption is measured between deposited nanospheres and other shaped NPs. FDTD simulations allow calculation of far and near field properties. The visualization of the NP interactions and the electric field enhancement, on and around the NPs, are studied to improve the understanding of the far field properties

Optical characterizations of multi-shape nanoparticles in polymer thin film layers

Recent progress in nanoparticle production gave a boost to nanotechnologies. Differently shaped and sized nanoparticles are produced by chemical synthesis in mild conditions. Nanoparticles have the potential to revolution the control of light matter interaction phenomena, thanks to their material, size, shape and environment dependence. In the search for a perfect absorber in the visible wavelength, silver nanospheres, nanoprisms and nanocubes are synthesized and successfully embedded in a thin film layer. Optical characterizations are coupled to FDTD simulations to analyze the optical behavior of the embedded nanoparticles. Each nanoparticle size and shape has a specific optical signature, which are modified by coupling phenomena between the nanoparticles. Optical properties of thin film layers containing nanoparticles are affected by the material, size, shape of the nanoparticles and their spatial distribution in the thin film layer

Design and realisation of organic-mettalic rectenna solar cells

International audienc