Natural convection in a trapezoidal enclosure with partial heating from below and symmetrical cooling from the sides has been investigated numerically. The heating is simulated by a centrally located heat source on the bottom wall, and four different values of the dimensionless heat source length, 1/5, 2/5, 3/5, 4/5 are considered. The laminar flow field is analyzed numerically by solving the steady, two-dimensional incompressible Navier-Stokes and energy equations. The Cartesian velocity components and pressure on a collocated (non-staggered) grid are used as dependent variables in the momentum equations discretized by finite volume method; body fitted coordinates are used to represent the trapezoidal enclosure, and grid generation technique based on elliptic partial differential equations is employed. SIMPLE algorithm is used to adjust the velocity field to satisfy the conservation of mass. The range of Rayleigh number is (103≤ Ra ≤105) and Prandtl number is 0.7. The results show that the average Nusselt number increases with the increases of the source length.
الحمد لله خالق الأكوان، وبارئ الإنسان، عظيم الشأن والإحسان، والصلاة والسلام على خاتم الأنبياء والمرسلين الصادق الأمين محمد وعلى آله الطيبين الطاهرين وعلى من سار على هديه بإحسان إلى يوم الدين.
أما بعد ...
فالقرآن الكريم هو ذروة الفصاحة والإعجاز والسلامة اللغوية يمثل بقراءاتهِ القرآنية المتعددة: المتواترة والشاذة والآحاد أصلا أصيلا للنحو العربي يحتج به في إقامة
... Show MoreAssyrian merchants established in the second millennium BC Assyrian commercial settlements in Anatolia, and these settlements had a great cultural value
ملامح من فكرة القانون الطبيعي في حضارة العراق القديم
Experience the Islamic financial industry faces many challenges, most notably the lack of proper risk management tools that meet the requirements of legality and economic efficiency advantage from another side, so it requires the search for innovative ways to manage the risk of Islamic banking, Islamic finance industry is manufacture up-to-date, if compared with the financial industry (traditional), which increases the problematic of risk management in the Islamic financial industry nature of treatment which should be compatible with Islamic law, as well as economic efficiency, thereby Progress came the importance of research to highlight the entrance to Islamic financial engineering and the goals sought to be achieved through the use of
... Show MoreAbstraet
Students dropout from the Education has a negative phenomena on individual and society and even on different aspects of life especially on the economic aspect , Thus our research tries studying and analyzing the relation between the size of dropout and human development level in Iraq and as (research sample) the first decade of this century as a studying period, the study includes the dropout in Secondary schools and depending the formal records as a main source to evaluate the size of this problem in Iraq , which shows an increase in the size of dropout in this period in comparison with the last decades of the twentieth century, this produces a negative effect on human developme
... Show MoreAbstract
The study aims to identify the common fears of preschool children and their relationship to the approaches to parental treatment in South Al Batinah Governorate from their mother’s point of view. Total of (466) mothers were selected as the study sample. The researcher used the scale of common fear and the scale of parental treatment approaches. The results of the study have shown that the most common fear among the study sample was (the fear of darkness) in the first level with a rate of 75.03%, and in the second level came the item (my child is afraid to sleep alone) by 72.74%, in the third level came to the item (fear of seeing insects) with a rate of 67.59%, and the last one was (the fear of rain) w
... Show MoreNeed organizations today to move towards strategic thinking which means analyzing situations faced by particular challenges of change in the external environment, which makes it imperative for The Organization That to reconsider their strategies and orientations and operations, a so-called re-engineering to meet those challenges and pressures, to try to achieve improvement root in the installation of the organization and methodscompletion of its work towards achieving high levels of performance and that is reflected to achieve its objectives, and this is what aims to Current search to deal with implications characteristics of strategic thinking in the stages of application re-engineering business of the company General Industries
... Show MoreNa+/K+-ATPase is a prevalent enzyme that maintains the Na+ and K+ gradients across the cell membrane by transporting three Na+ out and two K+ into the cell, the aim of this study is to provide detailed mechanistic insights, potentially with important effects on physiological regulation of active Na and K transport in tissues of Aerobic Thyroid Patient. Thyroid tissues were obtained from a 35 year old patients, the operation was carried out at the Al-Hadi Specialist Hospital in Samarra city, the sample was stored at -20ºC until used. The purification protocol included Salt Precipitation, Ion Exchange Chromatography, Gel Filtration and E
... Show MoreThe extraction of Eucalyptus oil from Iraqi Eucalyptus Camadulensis leaves was studded using water distillation methods. The amount of Eucalyptus oil has been determined in a variety of extraction temperature and agitation speed. The effect of water to Eucalyptus leaves (solvent to solid) ratio and particle size of Eucalyptus leaves has been studied in order to evaluate the amount of Eucalyptus oil. The optimum experimental condition for the Eucalyptus oil extraction was established as follows: 100 C extraction temperature, 200 rpm agitation speed; 0.5 cm leave particle size and 6: 1 ml: g amount of water to eucalyptus leaves Ratio.