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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. |
يؤدي عرض معلومات مضللة او محرفة ضمن القوائم المالية والتي تعد أهم مصادر المعلومات الموثوقة التي يُعول عليها لاتخاذ القرارات السليمة الى عدم قدرتها على عكس نتيجة النشاط والمركز المالي لها او اعمال الوحدة الاقتصادية لتلك الفترات الزمنية بصورة صادقة وعادلة نتيجة لنوعية المعلومات المفصح عنها في القوائم المالية لذلك زاد الاهتمام بتطوير الممارسات المحاسبية لتتضمن افصاحات كافية بغرض اعطائهم صورة صادقة وعادلة
... Show MoreThis study sheds light on the syndromes (grammatical pairs) in the section of sympathy, especially the affection and sympathy according to the normative rule governed by the synthetic correlation of the elements of the Arabic sentence and their structural composition, which leads to a verbal presumption governing their association with each other (called).
One of the syndromes of the grammarians is that which is between the emotion and his income, so they follow their functional and structural conditions, and they have also noticed a phenomenon that leads to their incompatibility and prevents their direct contact through the occurrence of a separation between them resulting in their separation, which is called separation. Grammar).
Background: Obesity and diabetes mellitus are the common health problems,and obesity is common cause of the insulin resistance. Aim of studv: Aim of the study is to find any correlation between obesity (insulin resistance) and type I diabetes in children. Patients and methods: This study included (40) children with type I diabetes, in addition to (40) children as control.The age of all studied groups ranged from (8-18) years.This study was attemted from Ibn AlBalady Hospital during from 20 August to 9 Novembar,2008. The subjects wrer divided into (4) groups according to their BMI:- * Obese children,diabetes,n=2O,BMI>30. * Non obese children, diabetes, n=20,BMI<25. Obese children, non diabetes, n=20,BMI>30. * Non obese children,non diabetes
... Show MoreIn this paper, some commonly used hierarchical cluster techniques have been compared. A comparison was made between the agglomerative hierarchical clustering technique and the k-means technique, which includes the k-mean technique, the variant K-means technique, and the bisecting K-means, although the hierarchical cluster technique is considered to be one of the best clustering methods. It has a limited usage due to the time complexity. The results, which are calculated based on the analysis of the characteristics of the cluster algorithms and the nature of the data, showed that the bisecting K-means technique is the best compared to the rest of the other methods used.
Background: Genetic factors play an important role in susceptibility to Guillain Barre' syndrome. Human leukocyte antigen (HLA) as part of immune system has a role in the disease process.Aim of the study: to assess the relationship between HLA-A alleles with Guillain Barre' syndrome (GBS) compared with a healthy control group using PCR-SSOP method.Type of the study: Cross-sectional study.Patients and methods:Patient's group consisted of 30 Iraqi Arab Muslims patients with Guillain Barre' syndrome that consulted the Neurological department in Neurosciences Hospital between January-2013 to January- 2014 were genotyped for HLA-A alleles. A control group consisted of 30 healthy volunteers among the staff of AL-Kindi College of Medicine that
... Show MoreThis research concluded that after what has been presented an analysis of the topics that the process of measuring the level of development and then the development gap is the need to assess the results to set policy and to formulate plans and goals, and to see the development priorities of the place or a particular sector. The purely economic development led to negative effects on the spatial scale and the most important of these effects arise multidimensional social and urban development gaps as well as the economic dimension. So it must exceed the concept of economic framework, to include all dimensions of development spatially and sectorally to provide correct and clear base for planners and development policies and strategies for de
... Show MoreBackground: Neonatal Septicemia (NNS) is generalized microbial symptomatic infection during the first 28 days of life.It>s the most serious complication in Neonatal Intensive Care Units (NICU) that demand urgent diagnosis and accurate treatment.Objective: To reveal the relationship of neonatal septicemia with birth weight (one of the neonatal risk factors).Patients and Methods: Blood sample was obtained from 76 neonates aged 1 hour-28 days who were diagnosed clinically (poor feeding, respiratory distress, fever, hypothermia, gastrointestinal and/or central nervous system symptoms)and bacteriologically to have neonatal septicemia.Results:One of the most important neonatal factor predisposing to infection is low birth weight, signi
... Show MoreThe research aims to review the concepts of banking efficiency and its relationship to performance, productivity and efficiency, as well as analyze the efficiency of the banking in micro-economic view.
In order to achieve the objectives of the research We have been employed graphic, Econometrics and Mathematical methods to derive the different concepts of banking efficiency.
We showed that there are two main methods used to measure the bank efficiency, the first called Stochastic Frontier Analysis , this technique depends on the parametric methods, The other method is called Data Envelopment Analysis is based on mathematical programming methods