The steady state laminar mixed convection and radiation through inclined rectangular duct with an interior circular tube is investigated numerically for a thermally and hydrodynamicaly fully developed flow. The two heat transfer mechanisms of convection and radiation are treated independently and simultaneously. The governing equations which used are continuity, momentum and energy equations. These equations are normalized and solved using the Vorticity-Stream function and the Body Fitted Coordinates (B.F.C) methods. The finite difference approach with the Line Successive Over-Relaxation (LSOR) method is used to obtain all the computational results. The (B.F.C) method is used to generate the grid of the problem. A computer program (Fortran 90) is built to calculate the steady state Nusselt number (Nu) for Aspect Ratio AR (0.55-1) and Geometry Ratio GR (0.1-0.9). The fluid Prandtl number is 0.7, Rayleigh number Ra = 400, Reynolds number Re = 100, Optical Thickness (0 ≤ t ≤ 10), Conduction- Radiation parameter (0 ≤ N ≤ 100) and Inclination angle λ = 45. For the range of parameters considered, results show that radiation enhance heat transfer. It is also indicated in the results that heat transfer from the surface of the circle exceeds that of the rectangular duct. Generally, Nu is increased with increasing GR, t and N but it decreased with AR increase. When the radiation effect added to the heat transfer mechanism, the heat transfer rate increased. This effect increased with increasing in GR and decreasing with AR. The increasing in radiation properties lead to increase the radiation effect. Tecplot 7 program was used to plot the curves which cleared these relations and isotherms and streamlines which illustrate the behavior of air through the channel and its variation with other parameters. A correlation equation is concluded to describe the radiation effect. Comparison of the results with the previous work shows a good agreement.
(2)
(2)
(31)
(27)
BACKGROUND: Vaccine hesitancy and reluctant had an important obstacle in achieving protection and population immunity against coronavirus disease 19 (COVID-19). It is essential to achieve high COVID-19 vaccination acceptance rates among medical students and health care workers to provide recommendations and counseling vaccine hesitant population. AIM: This study aims to identify level of COVID-19 hesitancy, attitude, knowledge, and factors that affect vaccination decision. MATERIALS AND METHODS: A cross-sectional study was done among medical students in Al-Kindy College of Medicine, University of Baghdad, Baghdad, Iraq. Data collection was done through an online Google Forms questionnaire during 2021 from 810 medical students.
... Show More
(13)
(10)
The study tagged ( the intellectual implications of the realistic Fine works of art) is a scientific effort to detect modest intellectual and artistic dimensions of the artwork realistic plastic , through some selected artistic productions of the painted work of art of the Iranian artist Ayman al - Maliki , with the result that the researcher collects materials to serve the scientific research topic which comes in three chapters.
First chapter included the general framework of the research (the promise of the research problem and its significance, objectives and limits and some of the terms contained therein).
Second chapter of this research was specified to the theoretical framework which included some of the topics that are dire
The dye–semiconductor interface between N749 sensitized and zinc semiconductor (ZnSe) has been investigated and studied according to quantum transition theory with focusing on the electron transfer processes from the N749 sensitized (donor) to the ZnSe semiconductor (acceptor). The electron transfer rate constant and the orientation energy were studied and evaluated depended on the polarity of solvents according to refractive index and dielectric constant coefficient of solvents and ZnSe semiconductor. Attention focusing on the influence of orientation energies on the behavior of electron transfer rate constant. Differentdata of rate constant was discussion with orientation energy and effective driving energy for N749-ZnSe system.
... Show More
(4)
The research includes synthesis and identification of novel three amino acids ligands complexes of some heavy metal (II) ions by using the amino acids like glycine, L-alanine and L-valine. New metal mixed ligand complexes with amino acids are prepared the reaction by reacting the three amino acids with the metals(II) chloride by using 50% ethanolic solution and 50% distall water in the molar ratio [1:1:1:1] ( M:Gly:Ala:Val) except for Co(II) and Ni(II) complexes were found after diagnosis the coordination with both Lalanine and L-valine. The prepared complexes identified by using physical properties, flame atomic absorption and conductivity measurements, in addition, mass, FT.IR and UV.vis spectrum as well magnetic moment data. The general
... Show MoreUropathogenic E. coli (UPEC) is problematic and still the leading cause of urinary tract infections worldwide. It is developed resistance against most antibiotics. The investigation, surveillance system, and efficient strategy will facilitate selecting an appropriate treatment that could control the bacterial distribution. The present study aims to investigate the epidemiology and associated risk factors of uropathogenic E. coli and to study their antibiotic resistance patterns. 1585 midstream urine specimens were collected from symptomatic urinary tract infections (UTI) patients (225 males and 1360 females) admitted to Zakho emergency hospital, Zakho, Kurdistan Region, Iraq from January 2016 until the end of December 2
... Show More
(28)
(11)
This paper deals with constructing mixed probability distribution from mixing exponential
(6)
<span>We present the linearization of an ultra-wideband low noise amplifier (UWB-LNA) operating from 2GHz to 11GHz through combining two linearization methods. The used linearization techniques are the combination of post-distortion cancellation and derivative-superposition linearization methods. The linearized UWB-LNA shows an improved linearity (IIP3) of +12dBm, a minimum noise figure (NF<sub>min.</sub>) of 3.6dB, input and output insertion losses (S<sub>11</sub> and S<sub>22</sub>) below -9dB over the entire working bandwidth, midband gain of 6dB at 5.8GHz, and overall circuit power consumption of 24mW supplied from a 1.5V voltage source. Both UWB-LNA and linearized UWB-LNA designs are
... Show More
(1)