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Free Convection in an Inclined Concentric Annular Square Cavities Filled With Porous Medium and Heated By Non-Uniform Temperature
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A numerical study of the two-dimensional steady free convection flow in an inclined annulus between two concentric square cavities filled with a porous medium is presented in this paper for the case when the side outer walls are kept with differentially heated temperature while the horizontal outer walls and the inner walls are insulated. The heated wall is assumed to have spatial sinusoidal temperature variation about a constant mean value. The Darcy model is used and the fluid is assumed to be a standard Boussinesq fluid. For the Cartesian coordinate system, the governing equations which were used in stream function form are discretized by using the finite difference method with successive under – relaxation method (SUR) and are solved by Gauss-Siedel iterative method. The upwind scheme was used for the transport terms in the energy conservation equation. The results are presented to demonstrate the streamlines, the isotherms, and the Nusselt number depending on the Rayleigh number ranging from (Ra =10 to 1000), dimension ratio from (Dr = 0.15 to 0.45), and the inclination angle from (= 0o to 45o). Also the effects of the amplitude (=0 to 1) and the wave number (f =0 to 5) of the heated side wall temperature variation on the free convection are investigated. The results show the effect of previous parameters (Ra, Dr,, , and f) on the flow fields and temperature profiles. It also show that the average Nusselt number is a strong function of the Rayleigh number, inclination angle, dimension ratio, and temperature variation. The peak value of the average Nusselt number based on the hot wall temperature is observed to occur at dimension ratio of (0.15), inclination angle of (40.1°), amplitude and wave  number (1 & 0.75) for Rayleigh number of (1000).

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Publication Date
Mon Feb 20 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Characterization of n-CdO:Mg /p-Si Heterojunction Dependence on Annealing Temperature
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In this research, thin films of CdO: Mg and n-CdO: Mg/ p-Si heterojunction with thickness (500±50) nm have been deposited at R.T (300 K) by thermal evaporation technique. These samples have been annealed at different annealing temperatures (373 and 473) K for one hour. Structural, optical and electrical properties of {CdO: Mg (1%)} films deposited on glass substrate as a function of annealing temperature are studied in detail. The C-V measurement of n-CdO: Mg/ p-Si heterojunction (HJ) at frequency (100 KHz) at different annealing temperatures have shown that these HJ were of abrupt type and the builtin potential (Vbi) increase as the annealing temperature increases. The I-V characteristics of heterojunction prepared under dark case at

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Publication Date
Sat May 01 2021
Journal Name
Key Engineering Materials
The Effect of Temperature Width on Dielectric Constant of Vanadium Dioxide
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A significant influence of temperature width found on the vanadium oxide properties, it plays a major role in highlighting the thermal limits of the three phases (metallic, semiconductor, and dielectric). Two values of the temperature width , and , had taken and studied their effect on both the dielectric constant and its two parts; refractive index, and extinction coefficient, and. It found that: as the temperature width is greater, the more the properties of the three phases for . In addition to increasing the thermal range for phases which can be reached to when , while it's at . Our results have achieved great compatibility with the published results globally. In addition to the effect of both ultraviolet, visible, and infrared

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Publication Date
Tue May 23 2023
Journal Name
Journal Of Engineering
Injection Temperature Effects on the Properties of High Density Polyethylene Crates
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This study was undertaken to provide more insight on the optimum injection temperature used for the production of PE crates, thereby saving time and money, and improving part quality. The work included processing trails of HDPE crates in an injection
molding machine at five temperatures ranged from 220 to 300°C. Both Rheological and mechanical characterization was conducted in order to understand the effect of injection temperature on the properties of crates. Oven aging was also applied for (4 weeks) to evaluate the long-term thermal stability. The results revealed that producing the crates at a temperature range of (260-280 °C) gives the best rheological and mechanical result. The lowest drop in thermal stability has been observed

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Publication Date
Mon Jun 19 2023
Journal Name
Journal Of Engineering
Retrofitting Reinforced Concrete One–Way Damaged Slabs Exposed to High Temperature
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Exposure of reinforced concrete buildings to an accidental fire may result in cracking and loss in the bearing capacity of their major components, columns, beams, and slabs. It is a challenge for structural engineers to develop efficient retrofitting techniques that enable RC slabs to restore their structural integrity, after being exposed to intense fires for a long period of time. Experimental
investigation was carried out on twenty one slab specimens made of self compacting concrete, eighteen of them are retrofitted with CFRP sheets after burning and loading till failure while three of them (which represent control specimens) are retrofitted with CFRP sheet after loading till failure without burning. All slabs had been tested in a

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Publication Date
Fri May 01 2020
Journal Name
Iop Conference Series: Materials Science And Engineering
A review of ultra-high temperature materials for thermal protection system
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Abstract<p>Ultra-High Temperature Materials (UHTMs) are at the base of entire aerospace industry; these high stable materials at temperatures exceeding 1600 °C are used to manage the heat shielding to protect vehicles and probes during the hypersonic flight through reentry trajectory against aerodynamic heating and reducing plasma surface interaction. Those materials are also recognized as Thermal Protection System Materials (TPSMs). The structural materials used during the high-temperature oxidizing environment are mainly limited to SiC, oxide ceramics, and composites. In addition to that, silicon-based ceramic has a maximum-use at 1700 °C approximately; as it is an active oxidation process o</p> ... Show More
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Publication Date
Thu May 18 2023
Journal Name
College Of Islamic Sciences
Similar judgments in the sacred heavenly books (Quran and the Bible): An analytical study
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The research tagged with (similar rulings in the holy heavenly books - the Holy Qur’an and the Bible) highlights that there are a number of rulings in the heavenly books that are similar to each other in terms of content, meaning and significance and did not change from one prophet to another because they relate to the basic interests on which social relations are built. Documenting ties, preserving rights, preventing abuse, etc. These are among the divine purposes in clarifying rulings in order to reach their goals and achieve their goals. Therefore, by combining these rulings, many problems and incidents that are the subject of disagreement and doubt between the two religions can be achieved and addressed. Those who want reform, righ

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Publication Date
Sun Mar 12 2017
Journal Name
Al-academy
Presence and Absence in the Iraqi Theatre Performance: Summer's Rain Play as an Example
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The presence and absence binary is an essential part of and a motivation for the direction vision which depends on the principle that the components of the theatre performance move in contrast with each other; one is directly informative which is the presence relations and the other is structural that is identical to the absence relations. The first is material band visual that evokes the incorporeal mental absent. Hence, the present study(Presence and Absence in the Iraqi Theatre Performance :Summer's Rain Play as an Example) aims at explaining those relations and their transformations between presence and absence in the performance

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Publication Date
Fri Feb 01 2019
Journal Name
Journal Of Economics And Administrative Sciences
A realistic vision of the ration card system in Iraq for the duration (1997-2003) and (2017-2003)
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Abstract:

The researcher shed light on a diet in Iraq before 2003 became in this period. And how the ration card has a variety of vocabulary and cover the need of the population of commodities and have a key role in saving Iraq from a real crisis in the period of economic siege, especially in light of the State's direction to support the agricultural sector, which in that period able to fill half of the market needs of food the basic. As well as providing strategic storage at the Ministry of Commerce enough for six months But after the events of 2003 and the crises that hit the country and the unstable security situation began to rise voices calling for reform of the ration card system as a system that is a burden on the

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Publication Date
Wed Sep 01 2010
Journal Name
Materials &amp; Design
Influence of glass addition and sintering temperature on the structure, mechanical properties and dielectric strength of high-voltage insulators
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Publication Date
Tue Jan 01 2019
Journal Name
Chemical Engineering Journal
Corrigendum to “Hierarchically porous zeolite X composites for manganese ion-exchange and solidification: Equilibrium isotherms, kinetic and thermodynamic studies” [Chem. Eng. J. 308 (2017) 476–491]
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