CONTRIBUTION AU DESIGN, STABILITÉ, PERFORMANCE ET OPTIMISATION D’UN UAV

Ce travail porte sur la simulation numérique, l’étude de performance, la stabilité et l’optimisation d’un modèle de drone (PIPER CUB J3).Dans ce but plusieurs logiciels de conception et de dessin assisté par ordinateur ont été utilisés : le modèle de l’UAV est conçu sous le logiciel « SolidWorks », les étapes de maillage et résolution des équations de Navier-Stokes décrivant l’écoulement sous « Ansys 16.0 », l’étude de stabilité et performance de vol par « Advanced Anlysis Aircraft 2.5 ».Pour des fins d’optimisation et d’amélioration en termes de finesse et d’endurance, trois types d’ailette ont été étudié

Study of No-Reference Video Quality Metrics for HEVC Compression, Journal of Telecommunications and Information Technology, 2016, nr 1

The paper proposes a No-Reference (NR) quality assessment measurement originally developed for H.264, used for High Efficiency Video Coding (HEVC). In particular, authors present an investigation of NR metrics to objectively estimate the perceptual quality of a set of processed video sequences. The authors take into account typical distortions introduced by the block-based coding approaches like HEVC codec. The underlying processing used for the quality assessment considers the blockiness caused by the boundaries of each coded block and the blurring as a lack of spatial details. The correlation between the NR quality metrics and the well-known and most widely used objective metric, the Video Quality Model (VQM), is performed to validate the quality prediction accuracy based on the provided scores. The Pearson correlation coefficients obtained stand for promising results for different types of videos

Rotavirus Strain Diversity in the Centre Coast of Tunisia from 2000 through 2003

An epidemiological survey investigating rotavirus infection in children was undertaken in the coastal region of Tunisia from January 2000 through September 2003. A total of 309 fecal specimens were screened by enzyme-linked immunosorbent assay and latex agglutination assay for the presence of group A rotavirus antigen. The detection rate was 26.2%. Rotavirus outbreaks showed a temperature-dependant pattern (P= .026) but no significant association with rainfall. Rotavirus strains isolated were analyzed by RNA polyacrylamide gel electrophoresis and were characterized antigenically by monoclonal antibodies to the VP6 subgroup. Eight RNA electropherotypes were identified, with 3 long and 5 short different RNA profiles. Among VP6 typeable strains, all isolates with a long electrophoretic pattern carried the subgroup II specificity, whereas those with a short profile belonged to subgroup I. In total, 48 rotavirus-positive samples were analyzed for G and P typing by reverse-transcription polymerase chain reaction. A total of 8 different G and P combinations were found: G1P[8] (35.7%), G1P[6] (21.4%), G2P[4] (4.8%), G3P[4] (4.8%), G4P[6] (4.8%), G8P[8] (4.8%), G3P[8] (2.3%), and G4P[8] (2.3%). Mixed infections were detected in 19.1% of stool samples. The emergence in Tunisia of unconventional types, such as G8VP7 specificity, highlights the need for a continual survey of the uncommon strains in North Afric

Indium-free multilayer semi-transparent electrodes for polymer solar cells

We have explored the fabrication of indium-free electrodes for use in a PCDTBT:PC70BM organic photovoltaic (OPV) device, and compare different multilayer electrodes as the device anode. Two oxide/metal/oxide structures were investigated that consisted of MoO3/Ag/MoO3 (MAM) and TeO2/Ag/MoO3 (TAM) multilayers. Using scanning electron microscopy measurements, we find that the electrode utilising a TeO2 seed layer encouraged the growth of a more continuous silver layer at low film thickness relative to an MoO3 seed layer, and thus combines enhanced optical transmission (by around 7%) with low sheet resistance (14 Ω/□). This enhanced optical transmittance results in an increased short-circuit current in photovoltaic cells, with TAM-based devices having a power conversion efficiency around 6% higher than those fabricated using a comparable MAM electrode

Organic pollutants in sea-surface microlayer and aerosol in thecoastal environment of Leghorn—(Tyrrhenian Sea)

The levels of dissolved and particle-associated n-alkanes, alkylbenzenes, phthalates, PAHs, anionic surfactants and surfactant fluorescent organic matter ŽSFOM. were measured in sea-surface microlayer ŽSML. and sub-surface water ŽSSL. samples collected in the Leghorn marine environment in September and October 1999. Nine stations, located in the Leghorn harbour and at increasing distances from the Port, were sampled three times on the same day. At all the stations, SML concentrations of the selected organic compounds were significantly higher than SSL values and the enrichment factors ŽEFsSML concentrationrSSL concentration. were greater in the particulate phase than in the dissolved phase. SML concentrations varied greatly among the sampling sites, the highest levels Žn-alkanes 3674 mgrl, phthalates 177 mgrl, total PAHs 226 mgrl. being found in the particulate phase in the Leghorn harbour. To improve the knowledge on pollutant exchanges between sea-surface waters and atmosphere, the validity of spray drop adsorption model ŽSDAM. was verified for SFOM, surface-active agents, such as phthalates, and compounds which can interact with SFOM, such as n-alkanes and PAHs. q2001 Elsevier Science B.V. All rights reserved

Sol-gel processing of highly transparent conducting Cd

Polycrystalline thin films of cadmium stannate (Cd2SnO4) (CTO) were coated on corning glass substrates by sol-gel method. The films were fired at different temperatures and annealed in inert ambient (N2) at 680°C. The structural, optical, and electrical properties of dip-coated cadmium-tin-oxide (CTO) thin films are discussed. CTO layers with a Hall mobility of 30 cm2/Vs and a carrier density of 1.4 × 1021 cm−3 resulting in a resistivity of 5 × 10−4 Ω cm have been deposited. Dip-coating conditions must be carefully monitored to produce consistent films. The high electronic conductivity is due to two effective mechanisms of n-type doping: (i) stoichiometric deviation and (ii) self-doping

Évaluation de la consommation d'oxygène au moyen d'un ergomètre brachial

L'ergomètre brachial permet d'effectuer des tractions en position couchée; de plus la résistance imposée est relative à la masse corporelle du sujet. Le but de l'étude est de valider une épreuve triangulaire discontinue sur l’ergomètre brachial. Dix étudiants en éducation physique, de sexe masculin et âgé en moyenne de 21,9 ans, ont passé un test et un retest. Les relations entre la puissance développée d'une part, et la consommation d'oxygène, la fréquence cardiaque et le débit ventilatoire d'autre part, sont linéaires et positives (r = .914; E<.001; r = .823; p<.001; r = .829; e<.001 respectivement). La mesure de la consommation d'oxygène du test au retest est fiable. La consommation maximale d'oxygène moyenne est de 1,38 ± 0,26 L-min-1, STPD (16,81 ± 2,96 ml-1 kg-1). La fréquence cardiaque maximale moyenne et le débit ventilatoire maximal moyen sont respectivement de 144 + 15 batt.-min'" et 46,0 ± 7,11 L-min'", BTPS. Cette limitation de la capacité de travail pendant les tractions brachiales est probablement reliée â un système d'inhibition centrale et périphérique