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Natural convection in an annular space provided with metal foam fins attached to the inner cylinder is studied numerically. The metal foam fins made of copper were inserted in different axial sections with three fins in each section. The temperature of the inner cylinder is kept constant while the annular outer surface is adiabatic. The thickness effect of the inner pipe wall was considered. Naiver Stokes equation with Boussinesq approximation is used for the fluid regime while Brinkman-Forchheimer Darcy model is used for metal foam. In addition, the local thermal non-equilibrium condition in the energy equation of the porous media is presumed. The effect of Rayleigh number and number of foam fins in the axial direction, on fluid flow and heat transfer characteristics, were examined. The current model was valid with the available published results and good agreement is noticed. Results showed that as the Rayleigh number increases the dominated of convection mode increases and average Nusselt increases. It was found that at Rayleigh of 106 Nusselt reached its higher value which is 4.6 for the case of adding seven axial metal foams. A comparison between adding foam fins and copper fins was established for a range of Rayleigh numbers between 104 and 106. It showed a good enhancement in Nusselt number and the greatest enhancement percentage was 45.9% at Rayleigh equal 106 for the case of using seven sections of foam fins. |
Objective(s): This study aims at determining the effectiveness of an educational program on knowledge of high school students' knowledge about substance abuse and its health consequences, and to find out the association between students’ knowledge about substance abuse and its health consequences and their demographic data of age, socioeconomic status, and educational level of parents.
Methodology: A quasi-experimental study is conducted for the period of October 28th, 2019 to March 30th, 2020. The study sample included a nonprobability “purposive” sample of (124) male students (62) students for the control group and (62) students for the study group, aged (14-19) years who are selected from Al-Hikma High School for Boys in Kirk
Acidizing is one of the most used stimulation techniques in the petroleum industry. Several reports have been issued on the difficulties encountered during the stimulation operation of the Ahdeb oil field, particularly in the development of the Mishrif reservoir, including the following: (1) high injection pressures make it difficult to inject acid into the reservoir formation, and (2) only a few acid jobs have been effective in Ahdeb oil wells, while the bulk of the others has been unsuccessful. The significant failure rate of oil well stimulation in this deposit necessitates more investigations. Thus, we carried out this experimental study to systematically investigate the influence of acid treatment on the geomechanical properties of Mi4
... Show MoreBackground: Fifteen percent of small for gestational age are small as a result of fetal growth restriction, which could be due to maternal, placental or fetal factors. It is an important clinical problem associated with increase perinatal mortality and morbidity. Leptin is a protein that produced by many tissues including the placenta (syncytiotropholoast). Dysregulation of leptin metabolism may be implicated in preeclampsia and IUGR pathogenesis.
Aim of the study: To study the trend of leptin level alteration in maternal serum and cord blood in pregnancies complicated by fetal growth restriction and its relation with fetal outcome.
Methods: An Analytic, cross- sectional study conducted in Al-Elwyia Maternity Teaching Hospital and
The research seeks to highlight the importance of digital finance in banking by providing financial and banking services and its role in improving the access of financial services to customers at the farthest possible point by using modern technology to finance their needs by granting them cash credits through electronic payment tools to facilitate them and shorten time and effort as well as Low cost, and this cannot be achieved without concerted efforts and the provision of basic infrastructure that includes connecting the Internet to all targeted areas, whether cities or rural areas, as well as distributing the largest possible number of ATMs and sending specialized teams to those areas that develop in customers the culture of digital
... Show MoreThe study aimed to find out the relationship between the dimensions of internal control systems and the availability of an effective governance framework in the Sudanese banks. The study used descriptive and analytical method for collecting and analyzing the study data using SPSS program. The questionnaire was used as an analysis tool. The target sample of Sudanese bank employees, the study found several results, including that the bank avoids methods that lead to the rational use of available resources, and identifies and separation of tasks among employees, in addition to rapid response to reports The study found several recommendations, including the need for a list of banks that are sufficiently flexible and comp
... Show Moreكان المؤتمر الآسيوي الأفريقي الأول الذي عُقد في مدينة باندونغ الاندونيسية عام 1955 هو المؤتمر هو الأول الذي اجتمعت فيه الدول الآسيوية والأفريقية بعد الحرب العالمية الثانية. كان مؤتمر باندونغ بمثابة نقطة الانطلاق نحو تأسيس حركة عدم الانحياز، والتي كانت مصر أحد أبرز أقطابها. شهد المؤتمر تقاربا في الآراء ووجهات النظر بين جمهورية مصر العربية وجمهورية الصين الشعبية، لا سيّما وإن الحكومة المصرية كانت قد تبنت س
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