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.
(40)
(33)
(6)
(3)
(25)
(18)
A method was developed that offers a rapid, simple and accurate technique for the determination of chlorophenols at trace levels in aqueous samples with very limited volumes of organic solvents. These compounds were acetylated, then preliminarily extracted with n-hexane. The enriched chlorophenols were directly analyzed using gas chromatography with an electron-capture detector. The detection limits were in the range of 0.001–0.005 mg/L, except for 2-chlorophenol, which was always above 0.013 mg/L. Relative standard deviation for the spiked water samples ranged from 2.2 to 6.1%, while relative recoveries were in the range of 67.1 to 101.3%.
(16)
(11)
Objective(s): To describe the demographic attributes, vaccination status of measles patients and the occurrence of
the disease according to time and place in Kirkuk governorate during the year 2010.
Methodology: The epidemiological study (a descriptive study) on measles cases was carried out in Kirkuk province
which is one of the Iraqi governorates from January 20th to July 30th, 2011. Data were collected retrospectively by
review of patients' files that were registered at the department of statistic in health directorate of Kirkuk during the
year 2010. A purposive "non-probability" sample of (152) confirmed measles cases (clinically and laboratory) that
were registered at the department of statistic in health directora
This is a research that deals with one of the topics of Arabic grammar, namely, the plural noun, and it is not hidden from the students the importance of grammatical topics in preserving the tongue from melody, and what it has of fundamental importance in knowing the graphic miracles of the Qur’an, and I called this research:
(plural noun in Arabic a grammatical study)
The name of God the Merciful
Praise be to Allah, Lord of the Worlds, and prayers and peace be upon the prophets and messengers Prophet Muhammad and his family
And his companions who followed his approach to the Day of Judgment. After that, Islam has paid great attention to the aspects of education
The promise of a way to degrade and correct behavior, and to reach the individual to the highest levels through his intellectual upbringing
Mentally, mentally, mentally and intellectually, education at all times and places is the best way to communicate to a human being
The degree of happiness in religion and the other, as it develops all aspects of his personality, and supports the love of goodness for himself
For people, edu
It is very well known in the planning publications that when creating spacing development to a region or sub-region, it can be able to make more than an alternative consisting with the strategic directions overtaken from the actual development of region and the situational and developmental objectives needed. However, the difficulty facing the situational planning is in selecting one of these alternatives to be the best in order to make a balanced situational re-structure, and achieving the economic, social and civil objectives. The developmental situation elements in the regions and governorates, including (Karbala) impose themselves as situational power which implies the process of re-structural arrangement where the situational develo
... Show More
Cyber security is a term utilized for describing a collection of technologies, procedures, and practices that try protecting an online environment of a user or an organization. For medical images among most important and delicate data kinds in computer systems, the medical reasons require that all patient data, including images, be encrypted before being transferred over computer networks by healthcare companies. This paper presents a new direction of the encryption method research by encrypting the image based on the domain of the feature extracted to generate a key for the encryption process. The encryption process is started by applying edges detection. After dividing the bits of the edge image into (3×3) windows, the diffusions
... Show More
(9)
(6)