Preferred Language
Articles
/
joe-567
Effect of Using Extra Fins on the Pin Fin Classic Geometry for Enhancement Heat Sink Performance using EGM Method
...Show More Authors

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.

 

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Sun Jul 09 2023
Journal Name
Journal Of Engineering
Influence of Aging Time on Asphalt Pavement Performance
...Show More Authors

Aging of asphalt pavements typically occurs through oxidation of the asphalt and evaporation of the lighter maltenes from the binder. The main objective of this study is to evaluate influence of aging on performance of asphalt paving materials.nAsphalt concrete mixtures, were prepared, and subjected to short term aging (STA) procedure which involved heating the loose mixtures in an oven for two aging period of (4 and 8) hours at a temperature of 135 o C. Then it was subject to Long term aging (LTA) procedure using (2 and 5) days aging periods at 85 o C for Marshall compacted specimens. The effect of aging periods on properties of asphalt concrete at optimum asphalt content such as Marshall Properties, indirect tensile strength at 25 o C,

... Show More
View Publication Preview PDF
Crossref (4)
Crossref
Publication Date
Mon Oct 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
measure the relationship between imported inflation and foreign trade in the Iraqi economy for long 1990-2015 using model nardl
...Show More Authors

The study aims to discuss the relation between imported inflation and international trade of Iraqi economy for the period (1990-2015) by using annual data. To achieve the study aim, statistical and Econometrics methods are used through NARDL model to explain non-linear relation because it’s a model assigned to measure non-linear relations and as we know most economic relations are non-linear, beside explaining positive and negative effects of imported inflation, and to reach the research aim deductive approach was adopted through using descriptive method to describe and determine phenomenon. Beside the inductive approach by g statistical and standard tools to get the standard model explains the

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Dec 01 2013
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The application target cost technique by using reverse engineering: An application study in the general company for vegetable oils industry
...Show More Authors

The Purpose of this study is mainly to improve the competitive position of products economic units using technique target cost and method reverse engineering and through the application of technique and style on one of the public sector companies (general company for vegetable oils) which are important in the detection of prices accepted in the market for items similar products and processing the problem of high cost which attract managerial and technical leadership to the weakness that need to be improved through the introduction of new innovative solutions which make appropriate change to satisfy the needs of consumers in a cheaper way to affect the decisions of private customer to buy , especially of purchase private economic units to

... Show More
View Publication Preview PDF
Publication Date
Sun Mar 20 2016
Journal Name
Al-academy
The Impact of using the strategy of shape (V) on the Achievement of the students of the Department of Artistic Education: كريم حواس علي، نجلاء خضير حسان
...Show More Authors

This research aim at finding out the impact of using the strategy of shape V on the achievement of the students of the Department of Artistic Education in the subject of "Principles of scientific Research ". This strategy is one of the cognitive strategies used in this topic . To verify the aim of the research ,the two researchers have put the following null hypothesis:-There are no significant differences on the level of 0,05 among the average degrees of the students of the experimental group in their answers on the topics of the pre and post cognitive achievement tests of the subject of "principles of scientific Research " . The two researchers have adopted the experimental approach which consists of one group . the population of the r

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Feb 10 2019
Journal Name
Iraqi Journal Of Physics
The effect of thickness on the optical properties of Cu2S thin films
...Show More Authors

In this work, the optical properties of Cu2S with different thickness
(1400, 2400, 4400) Ǻ have been prepared by chemical spray pyrolys
is method onto clean glass substrate heated at 283 oC ±2. The effect
of thickness on the optical properties of Cu2S has been studied. It
was found that the optical properties of the electronic transitions on
fundamental absorption edge were direct allowed and the value of the
optical energy gap of Cu2S (Eg) for direct transition decreased from
(2.4-2.1) eV with increasing of the thickness from (1400 - 4400)Ǻ
respectively. Also it was found that the absorption coefficient is
increased with increasing of thicknesses. The optical constants such<

... Show More
View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Thu Mar 18 2021
Journal Name
Energy & Fuels
Synergistic Effect of Nanoparticles and Polymers on the Rheological Properties of Injection Fluids: Implications for Enhanced Oil Recovery
...Show More Authors

New nanotechnology-based approaches are increasingly being investigated for enhanced oil recovery (EOR), with a particular focus on heavy oil reservoirs. Typically, the addition of a polymer to an injection fluid advances the sweep efficiency and mobility ratio of the fluid and leads to a higher crude oil recovery rate. However, harsh reservoir conditions, including high formation salinity and temperature, can limit the performance of such polymer fluids. Recently, nanofluids, that is, dispersions of nanoparticles (NPs) in a base fluid, have been recommended as EOR fluids; however, such nanofluids are unstable, even under ambient conditions. In this work, a combination of ZrO2 NPs and the polyacrylamide (PAM) polymer (ZrO2 NPs–PAM) was us

... Show More
Scopus (77)
Crossref (75)
Scopus Clarivate Crossref
Publication Date
Tue Oct 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
Solution of Fuzzy Maximal Flow Problems of Vehicles in Province of Diwaniyah Using the Ranking Function for Fuzzy Linear Programming Model
...Show More Authors

Abstract

The traffic jams taking place in the cities of the Republic of Iraq in general and the province of Diwaniyah especially, causes return to the large numbers of the modern vehicles that have been imported in the last ten years and the lack of omission for old vehicles in the province, resulting in the accumulation of a large number of vehicles that exceed the capacity of the city's streets, all these reasons combined led to traffic congestion clear at the time of the beginning of work in the morning, So researchers chose local area network of the main roads of the province of Diwaniyah, which is considered the most important in terms of traffic congestion, it was identified  fuzzy numbers for

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Mar 01 2020
Journal Name
Iraqi Journal Of Physics
Increasing the conversion efficiency of KTP crystal using the pump-power technique
...Show More Authors

In this study, the effect of pumping power on the conversion efficiency of nonlinear crystal (KTP) was investigated using laser pump-power technique. The results showed that the higher the pumping power values, the greater the conversion efficiency (η) and, as the crystal thickness increases within limitations, the energy conversion efficiency increases at delay time of (0.333 ns) and at room temperature. Efficiency of 80% at length of KTP crystal (L = 1.75 X 10-3 m) and Pin = 28MW, and also, compare the experimental results with numerical results by using MATLAB program. 

View Publication Preview PDF
Crossref
Publication Date
Thu Jan 05 2012
Journal Name
مجلة كلية التربية الأساسية/ جامعة بابل / بحوث المؤتمر العلمي الرابع لكلية التربية الأساسية/جامعة بابل 2011 م
THE DYNAMIC EVOLUTION OF THE SHELL NEBULAE BY USING INTERACTING WIND MODEL
...Show More Authors

Preview PDF
Publication Date
Tue Jan 01 2013
Journal Name
Iraqi Journal Of Physics
Describing the Wavefront Aberrations of the Hexagonal Aperture Using Modified Zernike Polynomials
...Show More Authors

n Segmented Optical Telescope (NGST) with hexagonal segment of spherical primary mirror can provide a 3 arc minutes field of view. Extremely Large Telescopes (ELT) in the 100m dimension would have such unprecedented scientific effectiveness that their construction would constitute a milestone comparable to that of the invention of the telescope itself and provide a truly revolutionary insight into the universe. The scientific case and the conceptual feasibility of giant filled aperture telescopes was our interested. Investigating the requirements of these imply for possible technical options in the case of a 100m telescope. For this telescope the considerable interest is the correction of the optical aberrations for the coming wavefront, th

... Show More