Narrow band resonant grating of 100% reflection under normal incidence

9 pagesInternational audienceA resonant grating mirror comprising a multilayer submirror and a grating slab waveguide submirror exhibiting constructive mutual reflection is shown experimentally to provide zero transmission. Its reflection line width of less than 1 nm, its polarization selectivity and low overall loss make the device usable as a longitudinal mode filter in a disk laser in the 1000-1100 nm wavelength range

Towards a standardization of biomethane potential tests

8 PáginasProduction of biogas from different organic materials is a most interesting source of renewable energy. The biomethane potential (BMP) of these materials has to be determined to get insight in design parameters for anaerobic digesters. A workshop was held in June 2015 in Leysin Switzerland to agree on common solutions to the conundrum of inconsistent BMP test results. A discussion covers actions and criteria that are considered compulsory ito accept and validate a BMP test result; and recommendations concerning the inoculum substrate test setup and data analysis and reporting ito obtain test results that can be validated and reproduced.The workshop in Leysin, Switzerland, has been financed by the Swiss Federal Office for Energy, and co-sponsored by Bioprocess Control Sweden AB, Lund, Sweden. The authors thank Alexandra Maria Murray for editing the English

Using enzymes to improve the process and the product quality in the recycled paper industry. 2 : industrial applications

International audienc

Rigidez do papelão ondulado: comparação entre resultados experimentais e os obtidos por cálculo analítico Bending stiffness evaluation of cardboard: comparison between experimental and analytically results

Embalagens de papelão ondulado para produtos hortícolas têm como função principal a proteção do produto. O dimensionamento de uma embalagem de papelão requer o conhecimento da rigidez à flexão, que depende dos módulos de elasticidade dos elementos que o constituem. Este trabalho teve por objetivo calcular, a partir da caracterização física do papelão em laboratório, o módulo de elasticidade por diferentes métodos, comparando os resultados com os valores obtidos experimentalmente. Dez corpos de prova de cada um dos papéis selecionados para este estudo foram testados na direção de fabricação e na direção transversal. A resistência à tração dos papéis, capa e miolo, utilizada para calcular a rigidez, foi determinada em máquina universal de ensaios. Para a obtenção da rigidez à flexão, foi realizado o teste de quatro pontos. Foi observada expressiva variação entre os métodos pelos quais se obtêm os módulos de elasticidade que reflete nos valores de rigidez da estrutura. Os valores de rigidez obtidos experimentalmente foram sempre superiores aos valores obtidos por cálculos analíticos. Essa diferença pode ser atribuída a dois fatores conjugados: o processo de fabricação que confere maior rigidez do que os componentes isoladamente, e o outro componente é a adição de camada adesiva que não é levada em consideração nos cálculos analíticos.<br>Cardboard packing for horticultural products has as main function to protect them. The design of a cardboard packing request the knowledge of the bending stiffens which is depending on the modulus of elasticity. The objective of this work was to calculate the cardboard modulus of elasticity from data obtained in laboratory using physical characterization test, with different methods, and comparing the results with the values obtained experimentally. Ten samples of each cardboard selected for this study were tested in the paper fabrication direction and in its transverse direction. The papers liner and medium resistance to the traction, used to calculate the bending stiffness, was determined in a universal machine test. To obtaining of the bending stiffens the four points test was accomplished. Expressive variations among the methods from which the modulus of elasticity is obtained were observed and that influence the bending stiffness of the structure. The stiffness values obtained experimentally were always greater than the values obtained from analytical method. This difference can be attributed to two factors, the production processes that assurance a larger rigidity than the components separately and the addition of the adhesive layer that is not taken in consideration in the analytic calculations

Characterization of aluminium nitride thin film structure using second-harmonic generation

International audienc

Caractérisation structurale et contraintes résiduelles de films d'AIN par diffraction des rayons X

L'état mécanique des couches minces influence considérablement leurs propriétés macroscopiques et notamment leur comportement tribologique. Ainsi, outre les caractéristiques structurales, la détermination des microdéformations et des contraintes résiduelles apparaît comme essentielle. Cette étude porte donc sur la caractérisation par diffraction des rayons X de l'état microstructural et mécanique de couches de nitrure d'aluminium élaborées par deux types de procédé : la nitruration d'aluminium par plasma induit par laser et le dépôt par pulvérisation cathodique. Les résultats montrent l'absence d'orientation préférentielle et de contraintes résiduelles dans les couches d'AIN laser-plasma, alors que les dépôts présentent une direction de croissance privilégiée et de fortes contraintes d'origine thermique.The mechanical state in thin films considerably influences their macroscopic properties, especially their tribological behaviour. It is the reason why microstrains and residual stresses determination is very important. This paper deals with the characterization by X-ray diffraction of the microstructural and mechanical state of aluminum nitride layers elaborated by two kinds of processing : laser induced plasma aluminum nitriding and magnetron sputtering deposition. Results show no preferential orientation and residual stresses in laser-plasma AIN films while deposits offer preferential growth direction and high stresses from thermal ones

Leaky mode mediated high efficiency grating excitation of heavily multimode slab waveguides

International audienc

99% efficiency measured in the -1st order of a resonant grating

International audienceA resonant diffraction grating comprising a mirror, a dielectric layer and a high index corrugation at the layer-air interface is shown to exhibit off-Littrow the record diffraction efficiency of 99% in the -1 st reflected order at 1064 nm wavelength thanks to the excitation of a leaky mode of the layer. Such high figure is obtained by a grating 5 to 10 times shallower than in current attempts to realize high efficiency all-dielectric gratings