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.
A new method for determination of allopurinol in microgram level depending on its ability to reduce the yellow absorption spectrum of (I-3) at maximum wavelength ( ?max 350nm) . The optimum conditions such as "concentration of reactant materials , time of sitting and order of addition were studied to get a high sensitivity ( ? = 27229 l.mole-1.cm-1) sandal sensitivity : 0.0053 µg cm-2 ,with wide range of calibration curve ( 1 – 9 µg.ml-1 ) good stability (more then24 hr.) and repeatability ( RSD % : 2.1 -2.6 % ) , the Recovery % : ( 98.17 – 100.5 % ) , the Erel % ( 0.50 -1.83 % ) and the interference's of Xanthine , Cystein , Creatinine , Urea and the Glucose in 20 , 40 , 60 fold of analyate were also studied .
Receipt Date:10/11/2021 Acceptance Date:29/12/2021 Publication Date:31/12/2021
This work is licensed under a Creative Commons Attribution 4.0 International License.
The study aimed to clarify the conceptual explanations and the theoretical rooting of the concept of the populist phenomenon. And explore the political and cultural implications and connotations contained in populist political discourse. And to stand on the foundations and meanings on w
... Show MoreThis research is an attempt to explore a social and pragmatic phenomenon of lamentation in elegies of Gray and AL-Khansaa' who represent two different cultures. It illustrates the intended meaning of lamentation in English and Arabic and finds how the two languages express this purpose of poetry by analysing it socio-pragmatically adopting Searle's models (1969),and its modifications. Lamentation is considered as a mournful poem lamenting the death of whole humanity as Gray's elegy and of an individual as AL-Khansaa's elegy. So, Gray portrays a universal picture concerning his lamentation, while AL-Khansaa' portrays an individual and subjective picture regarding her lamentation. As branches of linguistics, sociolinguistics de
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Objective: To evaluate the therapeutic activity of probiotics mixture of Lactobacillus plantarum and Lactobacillus acidophilus towards Cryptosporidium infection in experimentally infected mice. Oocysts of Cryptosporidium were separated from the stool of humans to infect mice. Methods: Forty male albino mice were split equally into four groups, every group contained 10 mice, the group I (early treated group), were treated from the 1st day from infection to the 11th post-infection, group II (late treated group), were treated from the 4th day from infection to the 15th post-infection, and group (III) (untreated group), were mice considered as a positive control group. Results: It was showed that daily application of a mixture of L. plantarum w
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Background: Drawing blood to measure total serum bilirubin is painful & time consuming. Transcutaneous bilirubinometer working by multiwavelength spectral reflectance from the skin surface on forehead or upper sternum is a quick & painless technique. Objectives: to compare the effectiveness of transcutaneous (over the upper sternum and forehead) and serum bilirubin measurement of neonate with jaundice. Subjects and Methods: This is a cross sectional prospective study. It enrolled 175 jaundiced neonates & excluded those exposed to phototherapy. It was conducted at Child Central Teaching Hospi |