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Numerical investigation of natural convection in a square enclosure partially filled with horizontal layers of a porous medium
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Abstract<p>Two‐dimensional buoyancy‐induced flow and heat transfer inside a square enclosure partially occupied by copper metallic foam subjected to a symmetric side cooling and constant heat flux bottom heating was tested numerically. Finite Element Method was employed to solve the governing partial differential equations of the flow field and the Local Thermal Equilibrium model was used for the energy equation. The system boundaries were defined as lower heated wall by constant heat flux, cooled lateral walls, and insulated top wall. The three parameters elected to conduct the study are heater length (7 ≤ <italic>ζ</italic> ≤ 20 cm), constant heat flux (150 ≤ <italic>q</italic>″ ≤ 600 W m<sup>−</sup><sup>2</sup>), and porous material thickness (5 ≤ <italic>H</italic> ≤ 20 cm). The porous material used was the copper metal foam of porosity = 0.9 and pore density PPI = 10, and saturated with a fluid of Prandtl number = 0.7. On the basis of the results obtained, it was concluded that at the porous layer thickness = 5 cm, the rate of heat transferred was (74.6%) higher than when the layer height was 20 cm (the cavity is fully filled) and at the same thickness it was found that the heat rate is (51.4%) higher than when using the half filling (<italic>H</italic> = 10 cm). Further, the local and mean Nusselt number is maximum when using the largest heater size and smallest porous layer thickness. Finally, better circulation and convective modes were observed at high values of heat flux.</p>
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Publication Date
Fri Jan 25 2019
Journal Name
Journal Of Al-qadisiyah For Computer Science And Mathematics Vol
Predicate the Ability of Extracorporeal Shock Wave Lithotripsy (ESWL) to treat the Kidney Stones by used Combined Classifier
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Extracorporeal Shock Wave Lithotripsy (ESWL) is the most commonplace remedy for kidney stone. Shock waves from outside the body frame are centered at a kidney stone inflicting the stone to fragment. The success of the (ESWL) treatment is based on some variables such as age, sex, stone quantity stone period and so on. Thus, the prediction the success of remedy by this method is so important for professionals to make a decision to continue using (ESWL) or tousing another remedy technique. In this study, a prediction system for (ESWL) treatment by used three techniques of mixing classifiers, which is Product Rule (PR), Neural Network (NN) and the proposed classifier called Nested Combined Classi

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Publication Date
Sat Jan 03 2026
Journal Name
Journal Of Baghdad College Of Dentistry
The relation between the mesio-distal crown widths of the deciduous second molars and the permanent first molars
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Background: This study aimed to find whether there is a relation between the mesio-distal crown diameters of the deciduous second molars and the permanent first molars in an Iraqi sample from Baghdad city. Material and methods: The sample consisted of 54 Iraqi children aged 8-9 years at the mixed dentition stage. The measurements included the mesio-distal crown width of the deciduous second molars and the permanent first molars on the study casts using digital sliding vernier. Results: The results revealed absence of the side difference of the widths of teeth measured. High significant gender difference was detected for the permanent first molars and the deciduous second molars except mandibular permanent first molar. On the other hand, hig

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Publication Date
Sun Jun 05 2016
Journal Name
Baghdad Science Journal
Synthesis and Characterization of New Heterocyclic Compounds from 2, 5- dimercapto -1, 3, 4-Thiadiazole and Their Resins
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In this research, a new 1, 3, 4-Thiadiazole derivatives have been synthesized by many heterocyclic reactions. Starting from (2, 5 – dimercapto -1, 3, 4-Thiadiazole) a variety of derivatives have been synthesis. Compound (1) was synthesized by the reaction of hydrazine hydrate with carbon disulphide in absolute ethanol. The compound (1) was reacted with 1, 2-dibromoethane in presence of alkali ethanol to give the compound (2). The compound (3) was formed from the reaction of compound (2) with hydrazine hydrate. Schiff base (4) was obtained by reacting of compound (3) with the compound (p-hydroxybenzaldehyde) in absolute ethanol. A variety of phenolic Schiff base (Methylolic, Etheric, and Epoxy) derivatives have been synthesized. Methylol

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Publication Date
Wed Jun 19 2019
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Evaluation the Procedure for Recognition of Income Tax to Reduce Tax Evasion: بحث تطبيقي في الهيئة العامة للضرائب
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  Tax state institution regards as one of the largest state institutions implementing the tax rules issuing be legislative body and achieving the goals of tax (financial, economic, social and political). So, the tax management should pay attention to the procedures enabling it to achieve those rules starting from the procedures of tax restrict and ending by tax allocation where the process of assessment the taxation must relaxing on modern methods. The problem of the study raising from that in spite of there is a low  obliging the taxable person (registered or not) to submit a declaration about his income and the achieved profit to be the base of taxation˒ where the other ways  are secondary ways helping in rejection of t

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Publication Date
Wed Feb 01 2023
Journal Name
Baghdad Science Journal
Synthesis and Structural Determination of 6-O-prop-2-ynyl-1,2:3,4-di-O-Isopropylidene-α-D-Galactose
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In this work, an important sugar alkynyl ether has been synthesized in two subsequent steps starting from commercially available D-galactose (3). This kind of compounds is highly significant in the synthesis of biologically active molecules such as 1,2,3-triazole and isoxazoles. In the first step, galactose (3) was reacted with acetone in the presence of anhydrous copper (II) sulfate to produce 1,2:3,4-di-O-isopropylidene-α-D-galactose (4) in good yield. The latter was reacted with excess of 3-bromoprop-1-yne in DMF in the presence of NaOH pellets to afford the target molecule 5 in a very good yield. The temperature of this step is crucial in determining the reaction yi

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Publication Date
Sun Jul 12 2020
Journal Name
Baghdad Science Journal
Geomagnetic Kp Index and Planetary Magnetosphere Size Relationship: for Mercury and Jupiter During two Types of Geomagnetic Conditions
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     Kp index correlates with the many magnetosphere properties, which are used to measure the level of magnetic activity. In the solar system, the two different planets, Mercury with weak magnetic field and Jupiter with strong magnetic field, are selected for this study to calculate the planet's magnetosphere radius (RMP) which represents the size of magnetosphere compared with solar activity through Kp index,  through two types of geomagnetic conditions; quiet and strong for the period (2016-2018). From the results, we found that there are reversible relations between them during strong geomagnetic storms, while there are direct relations during quiet geomagnetic conditions. Also it is found that the

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Publication Date
Mon Dec 01 2014
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The Dimensions Of Banking Service Quality and Its Rule On Customer's Satisfaction: Applied Study On Al- Rasheed Bank
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The purpose of this research is to recognize the relationship between the dimensions of  banking service quality and customer's satisfaction , through customer's evaluation of the level of service quality offered to them by Al – Rasheed bank. Also to determine the proportional importance of different dimensions of service quality. In addition to examine the relationship between banking service quality in its dimensions  and customer's satisfaction. (150 ) samples were distributed among the bank customers , only (130 ) samples were collected and good for analysis.

The results were analyzed and examined the hypothesis through a group of statistical methods. The most important results is the positive evaluation of the ba

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Publication Date
Sun Jun 12 2011
Journal Name
Baghdad Science Journal
Study the effective of annealing on the structural and sensitivity properties for SnO2 thin films to CO2 Gas
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In this research thin films from SnO2 semiconductor have been prepared by using chemical pyrolysis spray method from solution SnCl2.2H2O at 0.125M concentration on glass at substrate temperature (723K ).Annealing was preformed for prepared thin film at (823K) temperature. The structural and sensing properties of SnO2 thin films for CO2 gas was studied before and after annealing ,as well as we studied the effect temperature annealing on grain size for prepared thin films .

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Publication Date
Sat Oct 01 2011
Journal Name
Iraqi Journal Of Physics
Two dimensional grating and efficiency enhancement of Si photovoltaic cells by surface texturing using UV femtosecond laser pulses
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A fast laser texturing technique has been utilized to produce micro/nano surface textures in Silicon by means of UV femtosecond laser. We have prepared good absorber surface for photovoltaic cells. The textured Silicon surface absorbs the incident light greater than the non-textured surface. The results show a photovoltaic current increase about 21.3% for photovoltaic cell with two-dimensional pattern as compared to the same cell without texturing.

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Publication Date
Sat Nov 10 2018
Journal Name
Oriental Journal Of Chemistry
New Series of Substituted Heterocyclics Derived from α , β – Unsaturated Ketone and Their Cytotoxic Activity Tumor Cell Lines
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The aldol condensation of 2-acetylnaphthalene with 9-anthracene carboxaldehyde afforded α, β-unsaturated keton (1) . New heterocyclic compounds containing: cyclohexenone[2], indazole[3], pyrimidinethion [4], thiazolo fused pyrimidine[5], isoxazoline[6], substituted pyrazoline[7]a-d and pyrimidinone[8] rings system were synthesized from α, β-unsaturated keton[1]. Cyclization of [1] with ethylacetoacetate gave the mentioned heterocycle cyclohexanone [2]. The cyclo condensation of [2] with hydrazine gave the new indazole derivative [3]. furthermore, the reation of [1]with thiourea gives thiopyrmidine derivative [4]. The cyclo condensation of [4] with chloroacetic acid gave the fused rings [5]. Then reacted compound[1] with hydroxy

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