Analyse tectono-sédimentaire de la serie continentale Eocène du Djebel El-Kohol, près de Brézina (revers sud de l'atlas saharien) Algerire

L'analyse sédimentologique de 1'Eockne continental du Djebe El -Kohol (Brézina, revers sud de 1'Atlas saharien) a permis de mettre en évidence I'origine des dépots. L'interprétation des milieux de sédimentation et leur environnement t~enct ompte de l'analyse séquentielleverticale.Deux zones sont distinctes:d´une part, une zone proximale correspondants aux paléoreliefs du domaine atlasique émergé i la fin du Crétacé et sans cesser rajeunis par des mouvements compressifs et d'autre part, une zone distale s.1. ou zone d'enfoncement et comblement bien illustrée par une sédimentation diversifiée (évaporites, détritiques fins et grossiers) et oh sont observés des phénomknes de transformation par épigénie Les épandages détritiques d'El Koholproviennent essentiellement de l'érosion de 1'Atlas saharien durant la phase compressive intense d'age éockne largement ressentie dans les domaines tello-rifain et pyrénéo-provencal

Acoustic-roughness receptivity in subsonic boundary-layer flows over aerofoils

The generation of a viscous–inviscid instability through scattering of an acoustic wave by localised and distributed roughness on the upper surface of a NACA 0012 aerofoil is studied with a time-harmonic compressible adjoint linearised Navier–Stokes approach. This extends previous work by the authors dedicated to flat plate geometries. The key advancement lies in the modelling of the inviscid acoustic field external to the aerofoil boundary layer, requiring a numerical solution of the convected Helmholtz equation in a non-uniform inviscid field to determine the unsteady pressure field on the curved aerofoil surface. This externally imposed acoustic pressure field subsequently drives the acoustic boundary layer, which fundamentally determines the amplitudes of acoustic-roughness receptivity. A study of receptivity in the presence of Gaussian-shaped roughness and sinusoidally distributed roughness at Mach number M∞ = 0.4 and Strouhal numbers S ≈ {46, 69, 115} shows the effects of various parameters, most notably angle of attack, angle of incidence of the externally imposed plane acoustic wave and geometry of surface roughness; the latter is varied from viewpoint of its placement on the aerofoil surface and its wavelength. The parametric study suggests that non-parallel effects are quite substantial and that considerable differences arise when using parallel flow theory to estimate the optimal width of Gaussian-shaped roughness elements to provoke the greatest response. Furthermore, receptivity amplitudes for distributed roughness are observed to be generally higher for lower angles of attack, i.e. for less adverse pressure gradients. It is also shown that the boundary layer is more receptive to upstream-travelling acoustic waves

Le comportement d'un système hydrologique en climat méditerranéen par l'analyse corrélatoire et spectrale des débits et des pluies. Cas de trois sous bassins sud-méditerranéens : (oued Sebdou, Moulah et Isser - Tafna - NW Algérie)

Les analyses corrélatoire et spectrale des chroniques de la pluie (entrée) et de débits (sortie) journaliers enregistrés au niveau des trois bassins sud méditerranéens Sebdou, Mouilah et Isser durant un seul cycle hydrologique nous ont permis d’obtenir des informations sur le fonctionnement de ces systèmes hydrologiques. Bien que la structure du signal « pluie » semble présenter les mêmes caractéristiques pour les trois bassins, le signal de sortie « débit » indique que l’oued Sebdou réagit différemment par rapport aux oueds Mouilah et Isser.The aim of this work was to show that correlation and spectral analyses can be used to understand the functioning of hydrological systems. Accordingly, a study was carried out on three southern Mediterranean basins: Sebdou; Mouilah and Isser; located in the north western of Algeria. (Figure 1). Correlation and spectral analyses of daily rainfall and discharge rates for one hydrological cycle were carried out.Simple analysisSimple analysis of rainfall showed that the correlograms (Figure 2) decreased rapidly for the three basins, reaching a value of 0.2 within 1-2 days. This result indicated that rainfall was a quasi-random phenomenon. The variance density spectrum (Figure 3) showed that the rainfall distribution was not monotonous and presented a “Leigh” signal structure.The simple analysis of discharge rates indicated that the Sebdou system was different. The correlogram (Figure 4a) decreased quickly, characterising independent events without memory and with non-significant amounts of water. However, the Mouilah and Isser correlograms (Figure 4 b,c) decreased slowly. They represent important memory effects with regulation of significant amounts of water. The spectral band (Figure 5) confirmed that the Sebdou system did not modify the input information. The regulation time was about 5 d for Sebdou, 21 and 43 d respectively for Mouilah and Isser.Cross analysisThe correlograms (Figure 6) show that the Mouilah and Isser rivers have a great buffering ability. The Sebdou River was characterised by a composite response of the surface flow and an important groundwater flow. The amplitude function (Figure 7) indicated that the Sebdou system had good inertia. The lag time (Figure 8) was 9, 2 and 5 days respectively for the Sebdou, Mouilah and Isser rivers. The amplification and attenuation of the input signal (Figure 10) show that the Sebdou basin is the most karstified system. The non-linearity of the relationship between rainfall and discharge was expressed by the coherence coefficient (Figure 9), which was lower than 1

Optimization of conditions for in vitro pollen germination and pollen tube growth of date palm (Phoenix dactylifera L.)

Pollen germination and pollen tube growth might have a significant effect on fruit and seed production. This study was conducted to investigate the best medium for pollen germination and pollen tube growth of date palm male. Significant differences in percentages of pollen germination and pollen tube growth were observed between mediums. The use agar-based medium containing 5% of sucrose, 0.20 g/l boric acid, 0.42 g/l calcium nitrate, 0.1 g/l potassium nitrate and 0.22 g/l magnesium sulfate gave the best results in terms of germination and/or tube growth. The germination percentage was declined with polyethylene glycol and naphthaleneacetic acid, and inhibited completely with fructose, glucose and date extract. These results could have  implications not only for optimizing pollen management in date palm but also to select the best pollinizer for this specie.Keywords:<i> In vitro</i> pollen germination; Sucrose; Fructose; Glucose;  Naphthaleneacetic acid; basal medium

ESSAI DE LUTTE BIOLOGIQUE CONTRE LA PYRALE DES DATTES Apomyelois ceratoniae ZELLER, 1839 (LEPIDOPTERA : PYRALIDAE) PAR L’UTILISATION DE Phanerotomaflavitestacea FISHER (HYMENOPTERA : BRACONIDAE) ET Bracon hebetor SAY (HYMENOPTERA : BRACONIDAE) DANS LES CO

Notre étude porte sur des tes de lutte biologique à partir du cortège parasitaire autochtone de la pyrale des dattes (Apomyelois =Ectomyelois ceratoniae Zeller, 1839). Nous avons testé deux principaux auxilliares :Phanerotomaflavitestacea Fisher et Bracon hebetor Say.Les résultats obtenus montrent qu’il y a un effet significatif de l’action parasitaire des deux espèces étudiées sur le cycle biologique de la pyrale des dattes. Nous avons mesuré un taux de 58,50 dû au Phanerotoma et  100 % pour Bracon. La technique combinant l’utilisation des deux axillaires semble être une piste permettant de limiter la détérioration de la valeur marchande des dattes

Ascending aorta backward flow parameters estimated from phase-contrast cardiovascular magnetic resonance data: new indices of arterial aging

International audienceOur purpose was to estimate volume and flow rate parameters related to the backward flow in the ascending aorta (AA) using phase-contrast cardiovascular magnetic resonance (PC-CMR) and to evaluate their relationships with age and with well established arterial stiffness indices including wave reflection parameters in an asymptomatic group without overt cardiovascular disease

A brief overview of RF sputtering deposition of boron carbon nitride (BCN) thin films

A great part of interest has been paid for fabricating new materials with novel mechanical, optical, and electrical properties. Boron carbon nitride (BCN) ternary system was applied for variable bandgap semiconductors and systems with extreme hardness. The purpose of this literature review is to provide a brief historical overview of B4C and BN, to review recent research trends in the BCN synthesizes, and to summarize the fabrication of BCN thin films by plasma sputtering technique from B4C and BN targets in different gas atmospheres. Pre-set criteria are used to discuss the processing parameters affecting BCN performance which includes the gasses flow ratio and effect of temperature. Moreover, many characterization studies such as mechanical, etching, optical, photoluminescence, XPS, and corrosion studies of the RF sputtered BCN thin films are also covered. We further mentioned the application of BCN thin films to enhance the electrical properties of metal-insulator-metal (MIM) devices according to a previous report of Prakash et al. (Opt. Lett. 41, 4249, 2016).Qatar University (QU) - No. GCC-2017-007