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Numerical Study of Fluid Flow and Heat Transfer Characteristics in Solid and Perforated Finned Heat Sinks Utilizing a Piezoelectric Fan
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Numerical study is adapted to combine between piezoelectric fan as a turbulent air flow generator and perforated finned heat sinks. A single piezoelectric fan with different tip amplitudes placed eccentrically at the duct entrance. The problem of solid and perforated finned heat sinks is solved and analyzed numerically by using Ansys 17.2 fluent, and solving three dimensional energy and Navier–Stokes equations that set with RNG based k−ε scalable wall function turbulent model. Finite volume algorithm is used to solve both phases of solid and fluid. Calculations are done for three values of piezoelectric fan amplitudes 25 mm, 30 mm, and 40 mm, respectively. Results of this numerical study are compared with previous both numerical and experimental studies and give a good agreement. Numerical solution is invoked to explain the behavior of air flow and temperature distribution for two types of circular axial and lateral perforations. For each type, all the results are compared with an identical solid finned heat sink. Perforations show a remarkable enhanced in the heat transfer characteristics. The results achieved enhancement in the heat transfer coefficient about 12% in axial perforation and 25% in the lateral perforation at the maximum fan amplitude.

 

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Publication Date
Fri Nov 05 2021
Journal Name
Review Of International Geographical Education Online
Measuring The Efficiency of The Departments of The College of Administration and Economics / University of Baghdad Using the Method of Data Envelopment Analysis (DEA), A Comparative Study
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Publication Date
Fri Jan 01 2021
Journal Name
Review Of International Geographical Education Online
Measuring The Efficiency of The Departments of The College of Administration and Economics / University of Baghdad Using the Method of Data Envelopment Analysis (DEA), A Comparative Study
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The research aims at the possibility of measuring the technical and scale efficiency (SE) of the departments of the College of Administration and Economics at the University of Baghdad for a period lasting 8 years, from the academic year 2013-2014 to 2018-2019 using the method of Applied Data Analysis with an input and output orientation to maintain the distinguished competitive position and try to identify weaknesses in performance and address them. Nevertheless, the research problem lies in diagnosing the most acceptable specializations in the labor market and determining the reasons for students’ reluctance to enter some departments. Furthermore, the (Win4DEAp) program was used to measure technical and scale efficiency (SE) and rely on

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Scopus
Publication Date
Sun Dec 01 2019
Journal Name
Journal Of Economics And Administrative Sciences
Organizational monitoring and reflex of suffacation of work . An opinions study of sample workers in manufacturing of Isphelt dohuk
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The study aims to determine the organizational monitoring mechanism in target organization as well as knowing the suffocation of work. The study depends on a questionnaire as a tool of collecting data on distributed random sample involved (45) person from different   levels in manufacturing isphelt Dohuk. The study depends on some hypothesis, the most significant one is that there is not impact of organizational monitoring of suffocation especially on the target organization.

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Publication Date
Tue Dec 01 2009
Journal Name
Iraqi Journal Of Physics
Crystal Growth of High – Purity Bi2Se3 and Study of Crystal Structure
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The Bi2Se3 compound was synthesis by fusing initial compounds consisting of
extra pure elements in stoichiometric ratio from elements compound, charged inside
quartz ampoule. The crystal growth of Bi2Se3 carried out using Brighaman technique
process from melting f (Bi+Se ) at temperature of 810 ºC for about 48 hrs. Single crystal
of Bi2Se3 has been grown in direction (211) after slow cooling on account of heat
gradient to zone furnaces at cooling rate (1-3) C/hr. The structure study of the compound
was determined by x-ray diffraction technique, which it has bismuthinite structure and
orthorhombic unit cell with lattice parameters of a=10.2678 Å, b=11.2392 Å and
c=5.1737 Å

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Publication Date
Sun Dec 30 2018
Journal Name
Baghdad Science Journal
Synthesis and study of biological activity of some new Imidazole derivatives
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In this work ester derivatives were synthesized by the reaction of imidazole derivatives (C1) with ethylchloroacetate in ethanol and NaOH to give the corresponding (C2) .While compound (C3) acetohydrazide was synthesized by the reaction of ester derivatives (C2) with hydrazine hydrat in ethanol. Compound (C3) from the reaction with different aromatic aldehydes in absolute ethanol gave the Schiff′s bases (C4,C5). The product compounds were characterized by FT-IR, U.V and 1HNMR spectra and the biological activities were studied as antibacterial.

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Publication Date
Sat Feb 01 2020
Journal Name
Energy Reports
Study of photoemission and electronic properties of dye-sensitized solar cells
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We have investigated the photoemission and electronic properties at the PTCDI molecules interface on TiO2 and ZnO semiconductor by means of charge transition. A simple donor acceptor scenario used to calculate the rate for electron transfer of delocalized electronics in a non-degenerately TiO2 and ZnO electrodes to redox localized acceptors in an electrolytic. The dependent of electronic transition rate on the potential at contact of PTCDI with TiO2 and ZnO semiconductors, it has been discussion using TiO2 and ZnO electrodes in aqueous solutions. The charge transfer rate is determining by the overlapping electronic coupling to the TiO2 and ZnO electrodes, the transition energy, potential and polarity media within the theoretical scenario of

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Publication Date
Wed Oct 24 2018
Journal Name
Chalcogenide Letters
STUDY OF GEOMETRICAL AND ELECTRONIC PROPERTIES OF ZnS WURTZOIDS VIA DFT
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Publication Date
Sat Jan 30 2016
Journal Name
Ibn Al-haitham J. For Pure & Appl. Sci.
Study of Some Structural and Optical Properties of AgAlSe2 Thin Films
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The structural properties of ternary chalcopyrite AgAlSe2 compound alloys and thin films that prepared by the thermal evaporation method at room temperature on glass substrate with a deposition rate (5±0.1) nm s-1 for different values of thickness (250,500 and 750±20) nm, have been studied, using X-ray diffraction technology. As well as, the optical properties of the prepared films have been investigated. The structural investigated shows that the alloy has polycrystalline structure of tetragonal type with preferential orientation (112), while the films have amorphous structure. Optical measurement shows that AgAlSe2 films have high absorption in the range of wavelength (350-700 nm). The optical energy gap for allowed direct transition we

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Publication Date
Wed Jun 27 2018
Journal Name
Journal Of The College Of Education For Women
Kinds of unknowns and government linkages -empirical study of the application
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It is no secret that the prophets speech is of great importance, as the second source of Islamic legislation after the Holy Quran, and as such we must reserve and verify the authenticity of the novel and the narrators seizure, and all the conditions laid down by the scholars.

The subject of our research here concerns part of this verification, which is the unknown, the subject of the unknown hadith is considered a matter of great interest by the modernists because it relates to the validity of the novel and the narrators, and the methods of the modernists varied in terms of the reasons for this weakness, the fool never entertained them by the reckless narrative.

I chose the subject of my research the types of Mahjail and

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Publication Date
Fri Apr 30 2021
Journal Name
Al-kindy College Medical Journal
Slump Test versus Straight Leg Raise Test in the Diagnosing of Lumbar Disc Herniation: A Prospective Comparative Study
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Background: The clinical examination is one of the best suitable methods for diagnosis of low backache. Backache is one disease that the signs, clinical examination finding, and the results on imaging modalities not always related. The straight leg raising (SLR) and slump tests, can be used for diagnosis of lumber disc herniation.

Objectives: To compare the result of the slump test and SLR test in the diagnosis of lumber disc herniation.

Subjects and Methods: A prospective comparative study conducts on 280 patients in Al-Kindy teaching and private clinics complaints of backache, aging between 18-70 years old with acute or recurrent backache, sciatica pai

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