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Effect of Using Extra Fins on the Pin Fin Classic Geometry for Enhancement Heat Sink Performance using EGM Method
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In the present study, the effect of new cross-section fin geometries on overall thermal/fluid performance had been investigated. The cross-section included the base original geometry of (triangular, square, circular, and elliptical pin fins) by adding exterior extra fins along the sides of the origin fins. The present extra fins include rectangular extra fin of 2 mm (height) and 4 mm (width) and triangular extra fin of 2 mm (base) 4 mm (height). The use of entropy generation minimization method (EGM) allows the combined effect of thermal resistance and pressure drop to be assessed through the simultaneous interaction with the heat sink. A general dimensionless expression for the entropy generation rate is obtained by considering a control volume around the pin fin including a base plate and applying the conservations equations of mass and energy with the entropy balance. The dimensionless numbers used includes the aspect ratio (ε), Reynolds number (Re), Nusselt number (Nu), and the drag coefficients (CD). Fourteen different cross-section fin geometries are examined for the heat transfer, fluid friction, and the minimum entropy generation rate. The results showed that the Nusselt number increases with increasing the Reynolds number for all employed models. The ellipse models (ET and ER-models) give the highest value in the Nusselt number as compared with the classical pin fins. The fin of the square geometry with four rectangular extra fins (SR-models) gives an agreement in Nusselt number as compared with the previous study.

 

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Publication Date
Sun Jan 01 2017
Journal Name
Al–bahith Al–a'alami
The Motivations of Using Facebook by Old People and their Achieved Need
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This research deals with the motives of the use of Facebook by elderly people and the achieved needs, which leads the researcher to ask an important question: why an old persons use Facebook and are the achieved needs through   which they got?  The research aims to find out the habits and patterns of using Facebook by old men and stands on the main motives of the elderly in their use of Facebook. It also identifies the most prominent needs that have been made for the elderly as a result of their use of Facebook.

The research is a descriptive one in which the researcher uses survey method to achieve the desired goals. The researcher has chosen a group of old men from Diyala province. The total sample number is about

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Publication Date
Sat May 30 2020
Journal Name
Neuroquantology
Desertification Monitoring in the South-West of Iraqi Using Fuzzy Inference System
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In this research, the region in the south-west of Iraq is classified using a fuzzy inference system to estimate its desertification degree. Three land cover indices are used which are the Normalized Difference Vegetation Index, Normalized Multi-Band Drought Index and the top of atmosphere surface temperature to build a fuzzy decision about the desertification degree using eight decision roles. The study covers a temporal period of 38 years, where about every 10 years a sample is elected to verify the desertification status of the region, starting from 1990 to 2018. The results show that the desertification status varied every 10 years, wherein 2000 encountered the highest desertification in the south-west of Iraq.

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Publication Date
Wed May 31 2023
Journal Name
International Journal Of Advanced Technology And Engineering Exploration
Investigation of phase change characteristics for refrigerant R-134a flow in a double pipe heat exchanger with the use of thermal non-equilibrium model
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Almost all thermal systems utilize some type of heat exchanger. In a lot of cases, evaporators are important for systems like organic Rankine cycle systems. Evaporators give a share in a large portion of the capital cost, and their cost is significantly attached to their size or transfer area. Open-cell metal foams with high porosity are taken into consideration to enhance thermal performance without increase the size of heat exchangers. Numerous researchers have tried to find a representation of the temperature distribution closer to reality due to the different properties between the liquid and solid phases. Evaporation heat transfer in an annular pipe of double pipe heat exchanger (DPHEX) filled with cooper foam is investigated numerical

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Publication Date
Tue Aug 01 2023
Journal Name
Baghdad Science Journal
Reducing the Mutual Coupling of Cylindrical Circular Microstrip Antennas (CCMAs) Array Using EBG Structure
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A theoretical study to design a conformal microstrip antennas was introduced in this work. Conformal microstrip antennas define antennas which can be conformed to a certain shape or to any curved surface. It is used in high-speed trains, aircraft, defense and navigation systems, landing gear and various communications systems, as well as in body wearable. Conformal antennas have some advantages such as a wider-angle coverage compared to flat antennas and low radar cross-sectional (RCS) and they are suitable for using in Radome. The main disadvantage of these antennas is the narrow bandwidth. The FDTD method is extremely useful in simulating complicated structures because it allows for direct integration of Maxwell's equations depending o

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Publication Date
Mon Oct 22 2018
Journal Name
Journal Of Economics And Administrative Sciences
Measuring and analyzing the relationship between the fiscal policy indicators and the bank stability index in Iraq for the period 2010-2016 using the ARDL model.
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The importance of this research is to clarify the nature and the relationship between the indicators of financial policy and banking stability in Iraq, as well as to find a composite index reflects the state of banking stability in Iraq in order to provide an appropriate means to help policymakers in making appropriate decisions before the occurrence of financial crises.

     Hence, the problem of research is that the fiscal policy has implications for the macro economy and does not rule out its impact on banking stability. Moreover, the central bank does not possess a single indicator that reflects the stability of the banking system, rather than the scattered indicators that depend o

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Publication Date
Wed Apr 29 2020
Journal Name
Indian Journal Of Forensic Medicine & Toxicology
The Reliability of Orthodontic Treatment, According to the Needs of Patients Using the Dental Aesthetic Index
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Abstract Objectives: Malocclusion was and remains one of the most common problems which affects the psyche and social status of the individual, so the estimation of the malocclusion severity and needs a percentage of orthodontic treatment of Iraqi patients is the aim of this study. Method: A randomly selected 150 pairs of study models (48 male and 102 female) were involved in this study for patients attending an orthodontic clinic at College of Dentistry/ University of Baghdad seeking for treatment. The DAI scores were collected according to WHO guidelines directly from the study model with a digital caliper, score was calculated using the regression equation of 10 occlusal traits. The dental casts were classified into four groups to determ

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Publication Date
Thu Jun 30 2022
Journal Name
Journal Of Economics And Administrative Sciences
Using Genetic Algorithm to Estimate the Parameters of the Gumbel Distribution Function by Simulation
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In this research, the focus was on estimating the parameters on (min- Gumbel distribution), using the maximum likelihood method and the Bayes method. The genetic algorithmmethod was employed in estimating the parameters of the maximum likelihood method as well as  the Bayes method. The comparison was made using the mean error squares (MSE), where the best  estimator  is the one who has the least mean squared error. It was noted that the best estimator was (BLG_GE).

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Publication Date
Wed Aug 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
" Forecasting Future Cash Flows Using the Metrics of Cash Flow and the Accounting Return "
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Providing useful information in estimating the amount and timing and the degree of uncertainty concerning the future cash flows is one of the three main objectives of the financial reporting system, which is done through the main financial statements. The interest on standard-setting bodies in the forecasting of future cash flows, especially Financial Accounting Standards Board (FASB) explain under Accounting Standard (1) of the year 1978 "Objectives of Financial Reporting by Business Enterprises", paragraph (37) thereof that accounting profits better than cash flows when forecasting future cash flows, In contrast, IAS (7) as amended in 1992 aims to compel economic units to prepare statement of c

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Publication Date
Sun Nov 01 2020
Journal Name
Conference
Study the Response Of The Wind Turbine System under Realistic Working Conditions Using Simulink
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Abstract<p>In recent years, there has been a very rapid development in the field of clean energy due to the huge increase in the demand, which prompted the manufacturers and the designers to increase the efficiency and operating life of the energy systems and especially for wind turbine. It can be considered that the control unit is the main key of the wind turbines. Consequently, it’s essential to understanding the working principle of this unit and spotlight on the factors which influence significantly on the performance of wind turbine system. Simulink technique is proposed to find the response of the wind turbine system under different working conditions. In this paper, it was investigated</p> ... Show More
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Publication Date
Wed Feb 01 2023
Journal Name
Baghdad Science Journal
Study the Nuclear Structure of Some Even-Even Ca Isotopes Using the Microscopic Theory
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The root-mean square-radius of proton, neutron, matter and charge radii, energy level, inelastic longitudinal form factors, reduced transition probability from the ground state to first-excited 2+ state of even-even isotopes, quadrupole moments, quadrupole deformation parameter, and the occupation numbers for some calcium isotopes for A=42,44,46,48,50 are computed using fp-model space and FPBM interaction. 40Ca nucleus is regarded as the inert core for all isotopes under this model space with valence nucleons are moving throughout the fp-shell model space involving 1f7/2, 2p3/2, 1f5/2, and 2p1/2 orbits. Model space is used to present calculations using FPBM intera

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