Comparison of structural, morphological, linear and nonlinear optical properties of NiO thin films elaborated by Spin-Coating and Spray Pyrolysis

The paper reports on a comparative study of nickel oxide thin films prepared via two different elaboration methods spin-coating and spray pyrolysis. The structure and the surface topography of the NiO thin films have been studied by X-ray diffraction and the atomic force microscope. The optical properties of the deposited films were characterized with the analysis of the experimentally recorded optical transmittance data in the spectral wavelength range of 300–850 nm, via a JENWAY6715 UV–vis spectrophotometer. To complete the comparison, the third order nonlinear optical susceptibility was determined from the third harmonic generation experiment, which in turn were explored by the rotational Maker fringe technique using the beam of Nd:YAG laser at 1064 nm in picoseconds regime. The present work is aimed to exhibit the influence of the elaboration method on the physical properties through analyzing the obtained experimental results

Chemical variability and acaricidal activity of Rosmarinus officinalis L. essential oils

Rosemary leaves are characterized by two main periods of essential oils production and contain high levels of oils (2.11 to 3.13%). Their oils, extracted by hydrodistillation and analyzed by GC-FID and GC-MS, are dominated by oxygenated and hydrocarbons monoterpens and contain high amounts of 1,8-cineole. The chemical composition didn’t vary drastically during the phenologic stages, but a noticeable variability is however found within the ten studied populations. PCA and regression analysis revealed that among factors regulating the biosynthesis of oils during the different growth stages of the plant, the mean monthly temperature and monthly precipitation would be determinant. In hives bioassays, the use of absorbent paper pad impregnated by pure rosemary oil for six days showed certain effectiveness against Varroa mites. So, an application rate of 5ml of rosemary oil caused the highest mites mortalities, but the concentration of 3ml that producing an equivalent toxicity to flumetrin, is recommended. To overcome the phenomenon of resistance to chemicals widely used in apiaries infested by Varroa destructor, the use of pure rosemary oils as biopesticide for controlling acarian pests would be an appreciated tool

Fracture energy of wood and root burl wood of thuya (Tetraclinis articulata (Vahl) Masters)

International audienceThe fracture energy of wood and root burl wood of thuya, coming from the forest of Essaouira (Morocco), was measured using a single edge notched specimen bending (SENB) test method. The variations along the longitudinal and transverse directions were studied using specimens taken from one radial section of thuya wood and on radial section of thuya burl, originating from two different trees. Thuya burl was more resistant than thuya wood to crack propagation in RL system (in the tangential plane). This difference is explained by the presence of dark growths, composed of cells with thicker walls that make the burl wood usually denser than thuya wood. Thuya burl was more resistant to crack propagation in RL system (tangential plane) than in TL system (radial plane), which is consistent with the radial orientation of the dark growths. The observed decrease of fracture energy along the longitudinal direction was explained by the progressive reduction of dark growth concentration

Caractérisation physique du bois de la loupe de Thuya

International audienceCe travail constitue une contribution originale à l'étude de la densité et du retrait au séchage de la loupe de thuya provenant de la forêt de Khémisset (Maroc). La densité est souvent utilisée dans les étapes de prédiction des propriétés mécaniques du bois. Quant aux retraits linéaires, l'existence ou non d'une anisotropie entre les retraits radial, tangentiel et longitudinal préfigurent du comportement mécanique du bois. Les mesures de ces propriétés physiques sont réalisées sur 77 échantillons de 2×2×2cm3 découpés selon les directions radiale, tangentielle et longitudinale. L'analyse des résultats des mesures de densité permet de classer le bois de la loupe de thuya comme un bois dense. La densité de la loupe est plus élevée que celle du bois de thuya. Cette différence s'explique par la présence d'excroissances foncées composées de cellules aux parois plus épaisses que celles du bois de thuya. L'analyse des mesures de retraits montre une faible anisotropie de retraits, expliquée à l'échelle microscopique dans un plan de référence, par une orientation très variable des cellules. Ce résultat présuppose un comportement mécanique proche d'un comportement isotrope du bois de la loupe de thuya

STUDY OF THE FLUORESCENCE OF 9,9'-BIANTHRYL IN POLYVINYLALCOHOL AND IN POLYVINYLCHLORIDE AT 300-K AND 80-K

International audienceno abstrac

EFFECT OF SOLVENT POLARITY ON THE PROPERTIES OF THE EXCITED SINGLET-STATES OF 1,1'-BINAPHTYL - AN UV-VIS EMISSION-SPECTROSCOPY STUDY

no abstrac

Theoretical simulation of UV absorption spectrum of carbazole and some homocyclic analogues

no abstrac

FLUORESCENCE OF 9,9'-BIANTHRYL IN LIQUID SOLUTIONS AND IN POLYMERIC MEDIA OF LOW VISCOSITY AT ROOM-TEMPERATURE

no abstrac