Numerical Study for a Marine Current Turbine Blade Performance under Varying Angle of Attack

Energy generation from marine currents is a promising technology for sustainable development. The success of using marine current turbines to tap the ocean hydrodynamic energy depends on predicting the hydrodynamic characteristics and performance of such turbines. This paper presents an analysis of the two-dimensional flow using commercial CFD software over a marine current turbine blade. The 2D flow is simulated for HF-SX NACA foil modified from S1210 NACA foil at various angles of attack with Reynolds number of 19×104, which represents the marine current flow. The hydrofoil is designed with considerations for lift and drag coefficients. The flow is simulated by solving the steady-state Navier-Stokes equations coupled with the k-ω shear stress transport (SST) turbulence model. The aim of this work is to study the effect of the angle of attack on the lift and drag coefficients. The computational domain is composed of non-homogenous structured meshing, with sufficient refinement of the domain near the foil blade in order to capture the boundary layer effects. Hence, all calculations are done at constant flow velocity while varying the angle attack for every model tested. The results have shown that the drag and lift coefficient, Cd and Cl coefficient increases with increasing the value of the angle of attack, ratio Cl/Cd curve related on performance at the peak 7o angle of attack

EVALUATION OF SOME MALE TYPES AS POLLINATORS FOR BARHI DATE PALM cv. GROWN IN EGYPT

Four different date palm male types were chosen to evaluate which male could be recommended to use as a pollinator for Barhi date palm cv. grown in Egypt. Three male types namely Ghanamy, Fard and Boyr were grown in the Fruit Trees Experimental Station at Dibba, Fojaira, UAE, and the fourth male was an individual Sewy satellite seedling grown in Egypt. Number of spathe/palm; spathe weight, length, & width ; pollen grains weight / spathe ; average of strand length as well as pollen grains germination % were determined for each male date palm tree from each male type . Moreover, pollen grains from each male type were used as a pollinator to evaluate their effect on fruit set and fruit quality of Barhi date palm cv. This study was carried out during both 2004&2005 seasons. Data showed that both Ghanamy and Fard male type were superior in their morphological characters as compared with Boyr or Sewy satellite seedling male type. Boyr male type showed the lowest values of morphological characters. On the other hand, there were no great differences in pollen grains germination percentage. Moreover, the results clearly indicated that Ghanamy pollen recorded the highest significant fruit set percentage and bunch weight (Kg) in both seasons of study. While, Fard pollen produced the highest fruit weight (g), length, diameter, flesh weight& thickness and flesh %. Boyr and Sewy pollen showed the highest ratio of fruit length / diameter in both seasons. Data also revealed that dates that were picked from bunches pollinated with Fard pollen had the highest total soluble salts (T.S.S) value and the lowest tannins content

New role of antinutritional factors, phytic acid and catechin in the treatment of CCl4 intoxication

Both phytic acid (PA) and catechin (CA) are well known antioxidants of natural origin. They were frequently tried on experimental level as hepatoprotectants, relying only on their antioxidant properties. The present study was conducted mainly to outline the other biochemical pathways underlying the hepatotherapeutic potential of both drugs and to check a possible synergistic action if prescribed concomitantly. As both materials are frequently taken on a daily basis in food and drinks, it will be helpful to pursue their possible utility and/or to check if their value is really of medical importance. For this purpose, CCl4 was used as a hepatotoxin, we evaluated plasma total sialic acid (TSA), serum ascorbic acid (AA) levels, liver tissue thiobarbituric acid reactive species (TBARS) as a marker for lipid peroxidation and total protein (TP) content as a rough marker to measure hepatic synthetic capability in 80 male Wistar rats as experimental models. Animals were classified into 8 groups (10 rats each), the first as control, the second as PA treated (0.3 mg kg -1), orally, the third as CA treated (30 mg kg -1), intraperitoneally, the fourth given both drugs, as a single daily dose for 2 weeks. The same design was repeated 24 hours after CCl4-intoxication (1mL kg -1), intraperitoneally, as a single dose.The results revealed that both PA and CA when used individually, significantly down-regulated TSA in both physiologic (no CCl4 treatment) and pathologic (CCl4-intoxication) states accompanied by significant decrease in lipoperoxidation. The therapeutic action against TSA and the antioxidant power were abolished by co-administration of both drugs. AA was only decreased by PA and the combination in the physiologic state. Both PA and CA showed significant therapeutic effect for protein synthesis against CCl4-intoxication, but the combination abolished this effect. We conclude that both drugs can be considered as a chemotherapeutic against hepatopathies and we for the first time contraindicate the concomitant use of both drugs

Pt, Re and Pt–Re incorporation in sulfated zirconia as catalysts for n-pentane isomerization

Two groups of modified Sulfated Zirconia (SZ) catalysts were prepared by the sol–gel method. The first group was modified by four different concentrations of Pt metal (0.15, 0.30, 0.45 and 0.60 wt%), whereas the second group contained Pt–Re combinations on SZ. All the prepared catalysts were characterized by XRD, TPR, TEM, TGA, IR spectroscopy as well as surface properties using the BET method. The catalytic activity of the catalysts was examined for the hydroisomerization of n-pentane to iso-pentane. The catalytic activity was found to increase with increasing Pt concentration in the monometallic catalysts. The combination of Re ion with Pt on SZ results in significant changes in the characters and activities of the catalysts. The 0.45 wt%Pt + 0.15 wt%Re/SZ catalyst exhibited the highest selective compared to other metal ratios investigated