We have carried out multi color CCD surface photometry on the spiral galaxies NGC 4800 and NGC 2715 using 1.88 m optical telescope of Kottamia Astronomical Observatory. From these observations, the surface brightness, Ellipticity, position angle and color indices profiles are studied. Stellar populations in different regions of the galaxies are analyzed using color indices diagrams. We found that the galaxy NGC 4800 has a diffuse bright nuclear region and the asymmetry of the bar is due to the nonuniform distribution of dust in the galaxy. The color indices of the western inner spiral arm coincide with the corresponding mean color indices of the bar indicates that the stellar population of the bar is the same as that of the western spiral arm. The brightness of NGC 2715 remains constant at limited distance along the major axis. This may be attributed to the presence of a bar whose position angle is close to that of the galactic disk. This galaxy also showed reddening, and this is due to the presence of a huge amount of dust in the bulge to disk transition zone.
The different parameters on mechanical and microstructural properties of aluminium alloy 6061-T6 Friction stir-welded (FSW) joints were investigated in the present study. Different welded specimens were produced by employing variable rotating speeds and welding speeds. Tensile strength of the produced joints was tested at room temperature and the the effecincy was assessed, it was 75% of the base metal at rotational speed 1500 rpm and weld speed 50 mm/min. Hardness of various zones of FSW welds are presented and analyzed by means of brinell hardness number . Besides to thess tests the bending properties investigat
... Show MoreThis paper defines a method for sputtering high strength, extremely conductive silver mirrors on glass substrates at temperatures ranging from 20o to 22o C. The silver coated layer thicknesses in this work ranges from 7.5 to 16.1 nm using sputtering time from 10 to 30 min at power 25 W, 13.7 to 29.2 nm for time 10 to 30 min at 50 W, 15.7 to 26.4 nm for time 10 to 30 min at 75 W and 13.8 to 31.1 nm for time 10 to 30 min at 100 W. The optimum values of pressure and electrode gape for plasma sputtering system are 0.1 mbar and 5 cm respectively. The effect of DC sputtering power, sputtering duration or (sputtering time), and thickness on optical properties was investigated using an ultraviolet-visible spectrophot
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In this study, mixing of zinc oxide (ZnO) nanoparticles with iron oxide(Fe2O3) at (0, 0.1, 0.3, 0.5 and 1)%wt., are deposited on glass substrates by pulsed laser deposition (PLD) technique for study characterization ZnO:Fe2O3 as solar cell electrode. The profound effect of mixed film on the structural and optical of ZnO: Fe2O3 thin films was observed. Meanwhile, the films have polycrystalline Hexagonal structures for ZnO, Rhombohedra and cubic structure for Fe2O3, and as indicated by the X-ray diffraction patterns of the films. The mean crystallite size of ZnO increase with increasing mixed ratio. The direct energy
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Poly ethylene oxide PEO / Poly vinyl alcohol PVA blends were prepared by cast method at different ratios of (25%PEO/75%PVA, 30%PEO/70%PVA, 35%PEO/65%PVA, 40%PEO/60%PVA, and 50%PEO/505PVA). Samples miscibility ,and thermal stability were studied by using differential scanning calorimetry(DSC),and thermo gravimetric analysis (TGA) analysis. The results proved that there was one glass transition temperature (Tg=160°C) at 25%PEO\PVA ratio
)that was attributed to its miscibility. This miscibility associated with (Hydrogen bonds) between (Hydroxyl group) in PVA, and PEO, whereas there were two glass transition temperature for the blends ratio more than 30%PEO,that was due its immisc
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The x-ray fluorescence (XRF) of Znpc molecule with (flow of Ar) and Znpc molecule with (grow in N2) showed two peaks at (8.5and 9.5 Kv) referring to orbital transition ) K?-shell & K?-shell) respectively. The study of x-ray diffraction (XRD) where it was observed good growth of the crystal structure as a needle by the sublimation technique with a ?-phase of (monoclinic structure ) . Using Bragg equation the value of the interdistance of the crystalline plane (d-value) were calculated. We noticed good similarity with like once in the American Standards for Testing Material (ASTM) .Powder Diffraction File (PDF) Program was used to ensure the information obtained from (ASTM) . The output of (PDF) was compared with celn program, where the val
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This paper presents the thermophysical properties of zinc oxide nanofluid that have been measured for experimental investigation. The main contribution of this study is to define the heat transfer characteristics of nanofluids. The measuring of these properties was carried out within a range of temperatures from 25 °C to 45 °C, volume fraction from 1 to 2 %, and the average nanoparticle diameter size is 25 nm, and the base fluid is water. The thermophysical properties, including viscosity and thermal conductivity, were measured by using Brookfield rotational Viscometer and Thermal Properties Analyzer, respectively. The result indicates that the thermophysical properties of zinc oxide nanofluid increasing with nanoparticle volume f
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