216 research outputs found
Development of a Method for the Fast and Complete Assessment of Quality Characteristics in Undried Grass Silages by Means of an NIR-Diode Array Spectrometer
Traditionally, the determination of grass silage is very time consuming and needs a lot of manpower and chemicals. The advantages of conventional laboratory NIRS instruments are well known but their disadvantage lies in their lacking suitability for on-farm use. A new type of spectrometer based on diode arrays may be used for this purpose. However, these new instruments still need to be calibrated for an accurate estimate of the fermentative and nutritive value of wet and unchopped grass silage
EPR and SAXS studies of a TiO2-based gel
The response of a photosensitive TiO2-based gel to UV light is described. Upon irradiation, the gel adsorbs light at 365 nm and becomes dark blue due to the transformation of the Ti4+ centers into Ti3+. This behavior is revealed using electron paramagnetic resonance spectroscopy as a function of the gel chemical composition. The structure of the TiO2 network is studied by small angle x-ray scattering
Etudes in situ de la formation du carbonate de calcium CaCO3 synthétisé en milieu aqueux sous pression de CO2
National audienc
PLA scaffolds production from Thermally Induced Phase Separation: effect of process parameters and development of an environmentally improved route assisted by supercritical carbon dioxide
In this work, a relatively large scale of PLA scaffolds was produced using thermally induced phase separation (TIPS) combined with a supercritical carbon dioxide (SC-CO2) drying step as a green alternative. For the TIPS step, the phase separation of PLA and 1,4-dioxane solvent was controlled by adjusting the process conditions such as the polymer concentration and molecular weight, the 1,4-dioxane solvent power and the cooling conditions. The scaffolds morphology was analyzed by scanning electron microscopy. Their structural and mechanical properties were correlated together with the possibility to tune them by controlling the process conditions. An environmental analysis using the Life Cycle Assessment (LCA) methodology confirmed a reduction of at least 50% of the environmental impact of the whole process using the SC-CO2 drying compared to the traditional freeze-drying technology. This work is the first known attempt to conduct the LCA methodology on TIPS process for the PLA scaffolds production
Differential Dynamic Microscopy to characterize Brownian motion and bacteria motility
We have developed a lab work module where we teach undergraduate students how
to quantify the dynamics of a suspension of microscopic particles, measuring
and analyzing the motion of those particles at the individual level or as a
group. Differential Dynamic Microscopy (DDM) is a relatively recent technique
that precisely does that and constitutes an alternative method to more
classical techniques such as dynamics light scattering (DLS) or video particle
tracking (VPT). DDM consists in imaging a particle dispersion with a standard
light microscope and a camera. The image analysis requires the students to code
and relies on digital Fourier transform to obtain the intermediate scattering
function, an autocorrelation function that characterizes the dynamics of the
dispersion. We first illustrate DDM on the textbook case of colloids where we
measure the diffusion coefficient. Then we show that DDM is a pertinent tool to
characterize biologic systems such as motile bacteria i.e.bacteria that can
self propel, where we not only determine the diffusion coefficient but also the
velocity and the fraction of motile bacteria. Finally, so that our paper can be
used as a tutorial to the DDM technique, we have joined to this article movies
of the colloidal and bacterial suspensions and the DDM algorithm in both Matlab
and Python to analyze the movies
Microencapsulation of Proteins within Polymeric and Inorganic Particles using Supercritical CO2 Media
International audienc
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