A numerical investigation has been performed to study the effect of eccentricity on unsteady state, laminar aiding mixed convection in a horizontal concentric and eccentric cylindrical annulus. The outer cylinder was kept at a constant temperature
while the inner cylinder was heated with constant heat flux. The study involved numerical solution of transient momentum (Navier-Stokes) and energy equation using finite difference method (FDM), where the body fitted coordinate system (BFC) was
used to generate the grid mesh for computational plane. The governing equations were transformed to the vorticity-stream function formula as for momentum equations and to the temperature and stream function for energy equation.
A computer program (Fortran 90) was built to calculate the bulk Nusselt number (Nub) after reaching steady state condition for fluid Prandtl number fixed at 0.7 (air) with radius ratio ( =2.6), Rayleigh number (Ra=200), Reynolds number (Re=50) for both concentric and eccentric cylindrical annulus with different eccentricity ratios (ε=0, 0.25, 0.50, 0.75) and angular positions (φo=0o
, 45o , 90o , 135o , 180o ).
The results show a reasonable representation to the relation between Nusselt number and (ε, φo). Generally, Nub decreased with the increase in (ε and φo). Also, results show that the best thermal performance for the inner cylinder was at the angular
position (φo=0o ) for eccentricity ratio (ε=0.25), while the maximum reduction in the rate of heat transfer for the inner cylinder was at the angular position (φo=180o) for eccentricity ratio (ε=0.75).
Comparison of the result with the previous work shows a good agreement.
larization modulation plays an important role in polarization encoding in quantum key distribution. By using polarization modulation, quantum key distribution systems become more compact and more vulnerable as one laser source is used instead of using multiple laser sources that may cause side-channel attacks. Metasurfaces with their exceptional optical properties have led to the development of versatile ultrathin optical devices. They are made up of planar arrays of resonant or nearly resonant subwavelength pieces and provide complete control over reflected and transmitted electromagnetic waves opening several possibilities for the development of innovative optical components. In this work, the Si nanowire metasurface
... Show MoreFluconazole was used to test the susceptibility of Candida albicans isolated from different clinical samples, and to detect mutations in ERG11 gene, and their relationship to fluconazole resistance. Forty-eight isolates of Candida albicans were tested for susceptibility using the disc diffusion method (M-44). ERG11 genes of six isolates were amplified (four resistant, two susceptible) and sequenced. The sequenced genes were analyzed to detect the mutations. Out of 48 isolates of Candida albicans, 4 (8%) were resistant to fluconazole. Sixteen-point mutations were detected included 13 silent mutations, and three missense mutations. The mutations of A945C (E266D) and G1609A (V488I) were found only in susceptible Candida albicans isolates, whil
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... Show MoreThe study aimed to evaluate Glucagon-Like Peptide-1 levels in Polycystic ovary syndrome (PCOS) infertile female with Diabetes Mellitus (DM) and compare the results with control group, also, to find the correlation for GLP-1 with Luteinizing hormone (LH), Follicle stimulating hormone (FSH) and LH/FSH ratio that may be used in prediction atherosclerosis in these patients. The study included nineteen women with age ranged (30-40) years and BMI ranged between (30-35) Kg/m 2. Subjects were divided into two groups: group (1) consist of (45) females as a healthy control and group (2) consist of (45) infertile females with PCOS and DM as complication. Fasting serum glucose was determined by using commercial kits (Biolabo SA-France); LH, FSH, prolac
... Show MoreY Adnan, H Atiyah, IH Neamah…, International Development Planning Review, 2024