An experimental and numerical study has been carried out to investigate the forced convection heat transfer by clean or dusty air in a two dimensional annulus enclosure filled with porous media (glass beads) between two vertical concentric cylinders. The outer cylinder is of (82 mm) outside diameters and the inner cylinder of (27 mm) outside diameter. Under steady state condition; the inner cylinder surface is maintained at a high temperature by applying a uniform heat flux and the outer cylinder surface at an ambient temperature. The investigation covered values of input power of (6.3, 4.884, 4.04 and 3.26 W), Reynolds number values of (300, 700, 1000, 1500, and 2000) and dust ratio values (density number N) of (2, 4, 6 and 8). A computer program in MATLAB has been built to carry out the numerical solution by writing the governing equation in finite difference method. The local Nusselt number, the average Nusselt number, the contours of temperature field and velocity field were presented to show the flow and heat transfer characteristics. The results show that when clean air flow, the wall temperature gradually increases along the cylinder length in the direction of flow and decrease as Reynolds number increase while it increases with input power. For dusty air flow results show that the wall
temperature gradually increases along the axial direction and increase with Reynolds number and with input power, and the maximum reduction in heat transfer will be 30 % for N=8 at Re=2000. Comparison was made between the present experimental and numerical results and it gives good agreement. The experimental and numerical Nusselt number follows the same behavior with a mean
deviation of 12%.
The educational service industry is one of the most negatively affected industries by the spread of the COVID-19 pandemic. Government agencies have taken many measures to slow its spread, and then restrict movement and gatherings and stop recreational activities. Furthermore, the repercussions of the curfew had a significant impact due to the interruption in actual attendance for students and employees, and the severity of the Covid-19 crisis and its (economic, social, security, humanitarian and behavioral) effects on all societies and work sectors is no secret to anyone. Iraq, like other countries, was also affected by the negative impact of Covid-19 pandemic in all fields of institutional work, especially public fields, and specifically t
... Show MoreHerbal remedies are used in induction of lactation. In view of that .Borage Officinalis was employed to ensure an abundant milk supply or rectify milk insufficiency .However, this remedy has not been scientifically tested .The animals were treated with the aqueous extract of Borage Officinalis flowers at a daily concentration of 100 mg / kg body weight /ml for each rat through Oro-gastric tube for 14 days. Animals were subdivided into subgroups according to their physiological status. Mammary glands of these animals were processed for histological, histochemical and immunohistochemical studies. Parameters indicated that the aqueous extract of Borage Officinalis flowers induced lactogenesis in the mammmary glands of virgin and pregnant rats
... Show MoreHuman herpes virus-8 (HHV-8) infection has increased recently in Arabic countries. HHV-8 in healthy persons does not necessarily cause life-threatening infection, and however, it causes a more severe infection among immunocompromised patients. The distribution of HHV-8 genotypes varies according to ethnicity and depends on the geographic region prior rapid development of global travel. A cross sectional prospective study included a hundred healthy blood donor samples with a mean age of (36.60±10.381), 81% were positive for molecular detection of HHV-8 DNA. PCR results for HHV-8 were strongly related with risk factors such as the number of sexual relations, previous surgeries, blood transfusion, dental operation, and the number of b
... Show MoreBackground: Little is known about asymmetry of children's dental arches, the purpose of this study was to verify the presence of asymmetry of dental arches among Iraqi children in the mixed dentition stage. Materials and methods: The sample included 52 pairs of dental casts, 27 pairs belong to males and 25 pairs for females. Three linear distances were utilized on each side on the dental arch: Incisal-canine distance, canine-molar distance and incisal-molar distance, which represent the dental arch segmental measurements using the digital sliding calipers, which is accurate up to 0.02 mm. Results: No significant sides' differences with high correlation coefficient were found between the right and left incisal-canine, canine-molar and in
... Show MoreSome research reports that cognitive grammar (CG) theory has good contributions to teaching English as a foreign language. In this research, the researchers seek to apply this theory and its principles when teaching the simple present tense to Iraqi students who face difficulties in differentiating between the multiple usages of this tense. To achieve this objective, the researchers have conducted an experimental study on a group of 60 Iraqi students in the University of Baghdad, College of Education for Women. Langacker’s (2003) theory has been adopted in the analysis of the cognitive relations to understand the common and different connections of these usages of the simple present. The study has concluded that the cognitive grammar t
... Show MoreThe objective of the conventional well testing technique is to evaluate well- reservoir interaction through determining the flow capacity and well potential on a short-term basis by relying on the transient pressure response methodology. The well testing analysis is a major input to the reservoir simulation model to validate the near wellbore characteristics and update the variables that are normally function of time such as skin, permeability and productivity multipliers.
Well test analysis models are normally built on analytical approaches with fundamental physical of homogenous media with line source solution. Many developments in the last decade were made to increase the resolution of transient response derivation to meet the
... Show MoreThis study unveils the ideologies of women empowerment encoded in the Mona Lisa Smile movie (2003). It reveals how the stereotypical image of women born only to be wives and do the duties of upbringing and housework is challenged. Katherine Ann Watson (Julia Roberts), the main character in the movie, wants to make a difference in the next generation of women. She rejects the imposed traditional ideologies. Linguistically, she opposes conventional thinking and seeks to persuade her students that life is about more than getting married. The primary focus of this study is to examine and clarify how the characters’ linguistic choices convey their ideologies concerning the notion of women empowerment. To do this, the researchers apply
... Show MoreRecent phosphorus (P) pollution in the United States, mainly in Maine, has raised some severe concerns over the use of P fertilizer application rates in agriculture. Phosphorus is the second most limiting nutrient after nitrogen and has damaging impacts on crop yield if found to be deficient. Therefore, farmers tend to apply more P than is required to satisfy any P loss after its application at planting. Several important questions were raised in this study to improve P efficiency and reduce its pollution. The objective of this study was to find potential reasons for P pollution in water bodies despite a decrease in potato acreage. Historically, the potato was found to be responsible for P water contamination due to its high P sensitivity a
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