676 research outputs found

    Extremal functions for the anisotropic Sobolev inequalities

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    The existence of multiple nonnegative solutions to the anisotropic critical problem - \sum_{i=1}^{N} \frac{\partial}{\partial x_i} (| \frac{\partial u}{\partial x_i} |^{p_i-2} \frac{\partial u}{\partial x_i}) = |u|^{p^*-2} u {in} \mathbb{R}^N is proved in suitable anisotropic Sobolev spaces. The solutions correspond to extremal functions of a certain best Sobolev constant. The main tool in our study is an adaptation of the well-known concentration-compactness lemma of P.-L. Lions to anisotropic operators. Futhermore, we show that the set of nontrival solutions \calS is included in L∞(RN)L^\infty(\R^N) and is located outside of a ball of radius τ>0\tau >0 in Lp∗(RN)L^{p^*}(\R^N)

    Nehari manifold and existence of positive solutions to a class of quasilinear problema,

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    Abstract In this paper, existence and multiplicity results to the following nonlinear elliptic equatio

    Co-oligomers Based on 2-Methoxy, 5-(2’-ethylhexyloxy) phenylene and Thienylenevinylene for Organic Solar Cells

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    Thanks to their optoelectronic properties and specific applications such as organic solar cells, the research on the lower band gap of organic p-conjugated materials encompassing both polymers and oligomers have been widely studied over the last years. The control of the band gap of these materials is a research issue of ongoing interest. In this study, theoretical study using the DFT method on four oligomers based on 2-methoxy, 5-(2’-ethylhexyloxy) phenylene and thienylenevinylene is reported. The theoretical ground-state geometry and electronic structure of the studied molecules were obtained by the DFT method at the B3LYP level with a 6–31G (d) basis set. Theoretical knowledge of the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) energy levels the gap energy (Eg) and the open-circuit voltage (Voc) of the studied compounds are calculated and discussed. The results of this work suggest these materials as a good candidate for organic solar cells. DOI: http://dx.doi.org/10.17807/orbital.v8i3.80

    Improved Photocatalyzed Degradation of Phenol, as a Model Pollutant, over Metal-Impregnated Nanosized TiOâ‚‚

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    [Abstract] Photocatalyzed degradation of phenol in aqueous solution over surface impregnated TiO₂ (M = Cu, Cr, V) under UV-Vis (366 nm) and UV (254 nm) irradiation is described. Nanosized photocatalyts were prepared from TiO₂-P25 by wet impregnation, and characterized by X-ray diffraction, X-ray fluorescence, transmission electron microscopy, UV-Vis diffuse reflectance spectroscopy, Raman spectroscopy, and adsorption studies. No oxide phases of the metal dopants were found, although their presence in the TiO₂-P25 lattice induces tensile strain in Cu-impregnated TiO₂-P25, whereas compressive strain in Cr- and V-impregnated TiO₂-P25. Experimental evidences support chemical and mechanical stability of the photocatalysts. Type IV N₂ adsorption–desorption isotherms, with a small H3 loop near the maximum relative pressure were observed. Metal surface impregnated photocatalysts are mesoporous with a similar surface roughness, and a narrow pore distribution around ca. 25 Å. They were chemically stable, showing no metal lixiviation. Their photocatalytic activity was followed by UV-Vis spectroscopy and HPLC–UV. A first order kinetic model appropriately fitted the experimental data. The fastest phenol degradation was obtained with M (0.1%)/TiO₂-P25, the reactivity order being Cu > V >> Cr > TiO₂-P25 under 366 nm irradiation, while TiO₂-P25 > Cu > V > Cr, when using 254 nm radiation. TOC removal under 366 nm irradiation for 300 min showed almost quantitative mineralization for all tested materials, while 254 nm irradiation for 60 min led to maximal TOC removal (ca. 30%). Photoproducts and intermediate photoproducts were identified by HPLC–MS, and appropriate reaction pathways are proposed. The energy efficiency of the process was analysed, showing UV lamps are superior to UVA lamps, and that the efficiency of the surface impregnated catalyst varies in the order Cu > V > Cr.This research was partially supported by the Group of Chemical Reactivity & Photoreactivity at University and funded by the Spanish Ministerio de Economía y Competitividad through project CTQ2015-71238-R (MINECO/FEDER), and the regional government Xunta de Galicia (Project Grupo Potencial Crecemento (GPC) ED431B 2017/59), respectivelyXunta de Galicia; ED431B 2017/5

    Co-oligomers Based on 2-Methoxy, 5-(2’-ethylhexyloxy) phenylene and Thienylenevinylene for Organic Solar Cells

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    Thanks to their optoelectronic properties and specific applications such as organic solar cells, the research on the lower band gap of organic p-conjugated materials encompassing both polymers and oligomers have been widely studied over the last years. The control of the band gap of these materials is a research issue of ongoing interest. In this study, theoretical study using the DFT method on four oligomers based on 2-methoxy, 5-(2’-ethylhexyloxy) phenylene and thienylenevinylene is reported. The theoretical ground-state geometry and electronic structure of the studied molecules were obtained by the DFT method at the B3LYP level with a 6–31G (d) basis set. Theoretical knowledge of the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) energy levels the gap energy (Eg) and the open-circuit voltage (Voc) of the studied compounds are calculated and discussed. The results of this work suggest these materials as a good candidate for organic solar cells. DOI: http://dx.doi.org/10.17807/orbital.v8i3.80

    Actinobacillose (Shigellose) équine: à propos des premiers cas observés au Maroc

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    La septicémie néonatale due àActinobacillus equ uli (Actinobacillose, Shigellose) a été diagnostiquée chez deux poulains. Cliniquement, les animaux étaient faibles et refusaient de téter. Histo-pathlogiquement, de multiples micro-abcès ont été observés au niveau des reins, du foie, des glandes surrénales et du poumon. Actinobacillus equuli a été isolé à partir de certains organes.Equine actinobaciIIosis (Shigellosis): report of first cases in MoroccoN eonatal septicemia caused by Actinobacillus equuli (Actinobacillosis, Shigellosis) was diagnosed in two foals. Clinically the animaIs were weak, depressed and refused to nurse. Pathologically, multiple microabceses were observed in kidneys, adrenals, liver and lungs. Actinobacillus equuli was isolated from several organs

    Effects of Noise on Rabbit’s Blood

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    Experiments are described in which domestic rabbits were deliberately subjected to a daily 3-4 hours noise regime (65 dB) for 18, 28, 40 and 50 days, to determine its effects on the blood. Noise exposure to rabbits caused a general increase in its biochemical parameters such as urea, uric acid, creatinine, cholesterol, and triglycerides, while glucose level decreased significantly. Our results indicate a general decrease of total protein, albumin and globulin levels. The results indicated that noise exposure at split dose could be harmful. It found that recovery period were able to alleviate some of those harmful changes
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