Computational study of three-dimensional laminar and turbulent flows around electronic chip (heat source) located on a printed circuit board are presented. Computational field involves the solution of elliptic partial differential equations for conservation of mass, momentum, energy, turbulent energy, and its dissipation rate in finite volume form. The k-ε turbulent model was used with the wall function concept near the walls to treat of turbulence effects. The SIMPLE algorithm was selected in this work. The chip is cooled by an external flow of air. The goals of this investigation are to investigate the heat transfer phenomena of electronic chip located in enclosure and how we arrive to optimum level for cooling of this chip. These parameters, which will help enhance thermal performance of electronic chip and flow patterns, through the understanding of different factors on flow patterns. The results show the relation between the temperature rise, heat transfer parameters (Nu, Ra) with (Ar, Q) for two cases of laminar and turbulent flows.
In research it is an important phonemic change for the speaker to reach Ease and lightness ,wich is the kinetic follow-up , and we tried to collect the scattered matter in the various dialects
In research it is an important phonemic change for the speaker to reach Ease and lightness ,wich is the kinetic follow-up , and we tried to collect the scattered matter in the various dialects.
it is studied with the ancient and modern Showing the occurrence of this term between both sides Then we clarified the phoneme explanation for this phenomenon
ملخص البحث
العولمة ظاهرة اقتصادية سياسية اجتماعية لها انعكاساتها المختلفة على المجتمعات وعلى منظمات الأعمال في مختلف دول العالم، هذه الظاهرة أدت إلى المزيد من النتائج التي زادت منظمات الأعمال في الدول الغنية غناً وزادت منظمات الأعمال في دول العالم الثالث فقر، وقد ترتب على ذلك نتائج ايجابية لدى المجتمعات الغربية والمؤتلفة معها بسبب سيطرة منظمات الأعمال في تلك الدول على الأسواق في البلدان الن
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The research intended to take into consideration the phenomena of employing the temporary employees through the business organization increasingly, which has become one of the most apparent features of the contemporary strategy of the human resources management. It depends on the analytical descrptive Approach to meet the research problem which has been focalized around the dispute praising regarding the phenomena of the temporary employment and its dimensions and challenges which can be faced by the management of human resources as a result .The importance of the research is represented as one of rare research which confronts to the phenomena of the temporary employment in the Iraqi business environment. The most prominent objec
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احتلت قضية غسيل الاموال أهمية كبيرة على الساحة الاقتصادية العالمية خلال الفترة الاخيرة إدراكا من المجتمع الدولي لأثارها السلبية على الاستقرار الاقتصادي و خاصة على الاستثمار المحلي و الدولي و لذلك يتزايد الاهتمام بها و سبل مواجهتها من قبل العديد من الدول و المنظمات الدولية و المراكز المالية الكبرى , حيث تهدد هذه الظاهرة الاقتصاد العالمي و خاصة اقتصاديات العالم النامي و من بينها الاقتصاديات العربية .
ان
... Show MoreThe cost of microalgae harvesting constitutes a heavy burden on the commercialization of biofuel production. The present study addressed this problem through economic and parametric comparison of electrochemical harvesting using a sacrificial electrode (aluminum) and a nonsacrificial electrode (graphite). The harvesting efficiency, power consumption, and operation cost were collected as objective variables as a function of applied current and initial pH of the solution. The results indicated that high harvesting efficiency obtained by using aluminum anode is achieved in short electrolysis time. That harvesting efficiency can be enhanced by increasing the applied current or the electrolysis time for both electrode materials, where 98
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In this paper, we investigate and study quantum theoretical of quark-gluon interaction modeling in QGP matter formatted. In theoretical modeling, we can use a flavor number, strength coupling, critical energy Tc = 190 MeV, system energy (400-650)MeV, fugacity of quark and gluon, and photon energy in range of 1-10 GeV parameter to calculation and investigation spectrum of photon rate. We calculation and study the photon rate produced through bremsstrahlung processes from the stable QGP matter. The photon rate production from cg → dgy systems at bremsstrahlung processes are found to be increased with increased fugacity, decreased strength coupling, decreased the photons energy and temperature of system. The photons rate in cg → dgy is inc
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Abstract
This paper represents a study of the effect of the soil type, the drilling parameters and the drilling tool properties on the dynamic vibrational behavior of the drilling rig and its assessment in the drilling system. So first, an experimental drilling rig was designed and constructed to embrace the numerical work.
The experimental work included implementation of the drill-string in different types of soil with different properties according to the difference in the grains size, at different rotational speeds (RPM), and different weights on bit (WOB) (Thrust force), in a way that allows establishing the charts that correlate the vibration acceleration, the rate of penetration (ROP), and the power
... Show MoreThe researcher seeks to know the extent of applying the concept of design by Iraqi electronic press sites to provide media product with the acceptance of their browsers and ensure their repeated visits to such sites in the framework of the guiding rules for laser browsing. The researcher uses analytical study on a sample of six Iraqi electronic newspaper sites to identify the general features of their design and the methods of distribution of the structural elements of the pages. The researcher also conducts a field study on a sample of the surfers of electronic newspaper sites to see the extent of their evaluation to their design and the degree of their satisfaction.
Simple, sensitive and economical spectrophotometric methods have been developed for the determination of cefixime in pure form. This method is based on the reaction of cefixime as n-electron donor with chloranil to give highly colored complex in ethanol which is absorb maximally at 550 nm. Beer's law is obeyed in the concentration ranges 5-250 µg ml-1 with high apparent molar absorptivities of 1.52×103 L.mole-1. cm-1.