Large nonlinear Kerr effect in graphene

Under strong laser illumination, few-layer graphene exhibits both a transmittance increase due to saturable absorption and a nonlinear phase shift. Here, we unambiguously distinguish these two nonlinear optical effects and identify both real and imaginary parts of the complex nonlinear refractive index of graphene. We show that graphene possesses a giant nonlinear refractive index n2=10-7cm2W-1, almost nine orders of magnitude larger than bulk dielectrics. We find that the nonlinear refractive index decreases with increasing excitation flux but slower than the absorption. This suggests that graphene may be a very promising nonlinear medium, paving the way for graphene-based nonlinear photonics.Comment: Optics Letters received 12/02/2011; accepted 03/12/2012; posted 03/21/2012,Doc. ID 15912

Reduction of protein content and electrolyte balance to reduce nitrogen losses through volatilization in broilers

International audienc

Effects of crude protein content and electrolyte balance on nitrogen losses by volatilization in broilers

International audienc

New process for reduction of polluting emissions in livestock buildings

International @ AIR+LRE:AGFInternational audienceIt is of prime importance to reduce the emissions of methane and N2O, whether they emanate from stationary sources such as livestock buildings. There are several methods for eliminating air pollutants, which can be grouped into two main categories. One category comprises separation-and-recovery techniques such as absorption or adsorption, and the other category comprises the so-called destruction techniques such as catalytic combustion or decompositon. These latter techniques are more effective when the pollutants are present in trace amounts, but this requires the use of heterogeneous catalysts. In livestock buildings, the concentration of N2O and CH4 emitted are not constant over a day or seasons too [1]. To achieve the pollutants abatement, a catalyst constituted by a mixture of adsorbent support and active phase is proposed. This catalytic system will be capable of trapping N2O and CH4 and activating oxidation or decomposition processes. This improved process effectiveness is achieved. The aim of this project is to develop a simple, economical technology for catalytic treatment of nitrous oxide (N2O) and methane (CH4) emissions produced inside farm buildings used for intensive livestock breeding

Fermented Apple Pomace as a Feed Additive to Enhance Growth Performance of Growing Pigs and Its Effects on Emissions

Apple pomace is a by-product from the apple processing industry and can be used for the production of many value-added compounds such as enzymes, proteins, and nutraceuticals, among others. An investigation was carried out to study the improvement in the protein content in apple pomace by solid-state fermentation using the fungus Phanerochaete chrysosporium by tray fermentation method. The effect of this protein in terms of how it enriched apple pomace as animal feed for pigs has also been studied. There was a 36% increase in protein content in the experimental diet with 5% w/w fermented apple pomace. The efficiency of conversion of ingested food was increased from 43.5 ± 2.5 to 83.1 ± 4.4 in the control group and the efficiency of conversion of feed increased from 55.4 ± 4.5 to 92.1 ± 3.6 in the experimental group during the animal feed experiment. Similarly, the effect of a protein enriched diet on odor emission and greenhouse gas emission has also been studied. The results demonstrated that the protein enrichment of apple pomace by solid state cultivation of the fungus P. chrysosporium makes it possible to use it as a dietary supplement for pigs

Supplementary document for SuPyMode: An open-source library for design and optimization of fiber optic components - 6729967.pdf

Annexes with code and mathematical demonstrations

Baisse de la teneur en protéines et de la balance électrolytique pour réduire les pertes d'azote chez le poulet de chair

National audienc

Elucidating mechanisms in haem copper oxidases: The high-affinity Q(H) binding site in quinol oxidase as studied by DONUT-HYSCORE spectroscopy and density functional theory

The Cytochrome bo(3) ubiquinol oxidase (QOX) from Escherichia coli (E. coli) contains a redox-active quinone, the so-called "high-affinity'' Q(H) quinone. The location of this cofactor and its binding site has yet to be accurately determined by X-ray crystallographic studies. Based on site-directed mutagenesis studies, a putative quinone binding site in the protein has been proposed. The exact binding partner of this cofactor and also whether it is stabilised as an anionic semiquinone or as a neutral radical species is a matter of some speculation. Both Hyperfine Sub-level Correlation (HYSCORE) and Double Nuclear Coherence Transfer Spectroscopy (DONUT-HYSCORE) spectroscopy as well as density functional theory (DFT) have been applied to investigate the QH binding site in detail to resolve these issues. Use is made of site-directed variants as well as globally N-15/(14) N-exchanged protein. Comparison of computed and experimental C-13 hyperfine tensors provides strong support for the binding of the semiquinone radical in an anionic rather than a neutral protonated form. These results are compared with the corresponding information available on other protein binding sites and/or on model systems and are discussed with regard to the location and potential function of QH in the overall mechanism of function of this family of haem copper oxidases