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EXPERIMENTAL INVESTIGATION OF LAMINAR NATURAL CONVECTION HEAT TRANSFER IN A RECTANGULAR ENCLOSURE WITH AND WITHOUT INSIDE PARTITIONS
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Experimental study has been conducted for laminar natural convection heat transfer of air flow through a rectangular enclosure fitted with vertical partition. The partition was oriented parallel to the two vertical isothermal walls with different temperatures, while all the other surfaces of the enclosure were insulated. In this study a test rig has been designed and constructed to allow studying the effect of Rayleigh number, aperture height ratio, partition thickness, the position of aperture according to the side walls and according to the height, the position of the partition according to the hot wall, and partition inclination. The experiments were carried out with air as the working fluid for Rayleigh number range (5*107 – 1.3*108) and aspect ratio of (0.5). 22 different configurations of partition were used in this study these are:
a) Undivided enclosure (no – partition).
b) (21) Cork partitions of different shapes.
Empirical correlations for average Nusselt number are obtained for the different cases tested. The results show that heat transfer is independent on the partition position according to the cold wall and according to the upper or lower walls, while it shows that heat transfer is sensitive to:
1. Rayleigh number (Ra), which increase with increasing Ra.
2. Aperture height ratio (Ap=hp/H), which is found that when Ap= 5/6 (case 2,3), the reduction in heat transfer is 10.3%, while when Ap=1/2 (case 4,5), the reduction is 17.2% compared with the non partitioned enclosure.
3. Aperture position according to the height, which is found that when the aperture at the centre of the partition (case 13), the reduction in heat transfer is 16.7%, while when the aperture displaced to the upper surface (case 14), the reduction is 19% compared with the non partitioned enclosure.
4. Partition thickness (t), which is found that when t = 10 mm (case 4,5) the reduction in heat transfer is 17.2%, while when t = 150 mm (case 16) the reduction is 20.5% compared with the non partitioned enclosure.
5. Partition inclination (), which is found that the rate of heat transfer reduced with increasingas shown:
a. For = 30 toward the cold wall (case 22), the reduction in heat transfer is 18.2%.
b. For = 45 toward the cold wall (case 18), the reduction in heat transfer was 21.9%.
c. For = 60 toward the cold wall (case 20), the reduction in heat transfer is 30.2%.
d. For = 30 toward the hot wall (case 21), the reduction in heat transfer is 31.3%.
e. For = 45 toward the hot wall (case 17), the reduction in heat transfer is 40.7%.

f. For = 60 toward the hot wall (case 19), the reduction in heat transfer is 42.1%.

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Publication Date
Thu Mar 01 2007
Journal Name
Al-khwarizmi Engineering Journal
An experimental comparative study between polypropylene and laminated lower limb prosthetic socket
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Most researchers concentrate their studies on the design, stress and pressure distributions of the prosthetic socket. A little attention is considered for the stiffness of the various materials of the prosthetic sockets. Prosthetic laminated sockets in Iraq are costly to be manufactured while polypropylene socket is relatively cheap in comparing with the laminates.

Experimental study is conducted to compare the stiffness of five prosthetic sockets made of different materials. Compression, three point flexural and tensile tests are implemented by the Testometric machine. The laminate sockets give better results in compression than polypropylene. Polypropylene gives good results in bending compared with the laminate sockets. When t

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Publication Date
Sun Dec 09 2018
Journal Name
Baghdad Science Journal
Enhancement of the Tensile and the Compression Properties for Heat- Cured Acrylic Resin Denture Base Materials
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This work aims to investigate the tensile and compression strengths of heat- cured acrylic resin denture base material by adding styrene-butadiene (S- B) to polymethyl methacrylate (PMMA). The most well- known issue in prosthodontic practice is fracture of a denture base. All samples were a blend of (90%, 80%) PMMA and (10%, 20%) S- B powder melted in Oxolane (Tetra hydro furan). These samples were chopped down into specimens of dimensions 100x10x2.5mm to carry out the requirements of tensile tests. The compression strength test specimens were shaped into a cylinder with dimensions of 12.7mm in diameter and 20mm in length. The experimental results show a significant increase in both tensile and compression strengths when compared to cont

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Publication Date
Fri Jun 30 2017
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Upgrading of Al-Rustamiyah Sewage Treatment Plant Through Experimental and Theoretical Analysis of Membrane Fouling
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Al-Rustamiyah plant is the oldest and biggest sewage treatment plant in Iraq; it locates in the south of Baghdad city. The plant suffers from serious problems associated with overflow and low capacity. The present work aims to upgrade the heart of biological treatment process through suggesting the use of membrane bioreactor; (MBR). In this work, fouling of membrane during sewage treatment has been analyzed experimentally and theoretically by fouling mechanisms. Aeration has been applied in order to control fouling through producing effective diameters of air bubbles close to the membrane walls. Effect of air flow rate on flux decline was investigated. Hermia's models were used to investigate the fouling mechanisms. The results showed th

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Publication Date
Fri Mar 31 2017
Journal Name
Journal Of Engineering
Experimental Measurements of Viscosity and Thermal Conductivity of Single Layer Graphene Based DI-water Nanofluid
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Experimental measurements of viscosity and thermal conductivity of single layer of graphene . based DI-water nanofluid are performed as a function of  concentrations (0.1-1wt%) and temperatures between (5 to 35ºC). The result reveals that the thermal conductivity of GNPs nanofluids was increased with increasing the nanoparticle weight fraction concentration and temperature, while the maximum enhancement was about 22% for concentration of 1 wt.% at
35ºC. These experimental results were compared with some theoretical models and a good agreement between Nan’s model and the experimental results was observed. The viscosity of the graphene nanofluid displays Newtonian and Non-Newtonian behaviors with respect to nanoparticles concen

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Publication Date
Tue Dec 01 2020
Journal Name
Baghdad Science Journal
Optimization of Voltammetric Determination of Dysprosium (III) Using Plackett-Burman and RSM-CCD Experimental Designs
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This study was aimed to develop an optimized Dy determination method using differential pulse voltammetry (DPV). The Plackett-Burman (PB) experimental design was used to select significant factors that affect the electrical current response, which were further optimized using the response surface method-central composite design (RSM-CCD). The type of electrolyte solution and amplitude modulation were found as two most significant factors, among the nine factors tested, which enhance the current response based on PB design. Further optimization using RSM-CCD shows that the optimum values for the tw

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Publication Date
Mon Jan 01 2024
Journal Name
Wiadomości Lekarskie
Evaluation of clinical and demographical finding in patients with oral lichen planus: A retrospective cross sectional study
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Aim: To learn more about Oral Lichen Planus Iraqi patients, including their background information, symptoms, and prognosis. Materials and Methods: From the Oral and Maxillofacial Pathology Department, College of Dentistry, Baghdad University, we retrospectively reviewed the medical records of 68 patients with a histologically confirmed clinical diagnosis of oral lichen planus and subsequently contacted the patients by phone to evaluate their prognosis. Results: Females were more likely than males to experience severe pain; the reticular form of Oral Lichen Planus was the most prevalent at 38.2%, but the erosive type was more prevalent among females. Only 53 of 68 patients responded to phone calls. More than 37% of those respondents reporte

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Publication Date
Tue Dec 24 2024
Journal Name
Malaysian Journal Of Mathematical Sciences
Exploring the Role of Hunting Cooperation, and Fear in a Prey-Predator Model with Two Age Stages
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The aim of this study is to utilize the behavior of a mathematical model consisting of three-species with Lotka Volterra functional response with incorporating of fear and hunting cooperation factors with both juvenile and adult predators. The existence of equilibrium points of the system was discussed the conditions with variables. The behavior of model referred by local stability in nearness of any an equilibrium point and the conditions for the method of approximating the solution has been studied locally. We define a suitable Lyapunov function that covers every element of the nonlinear system and illustrate that it works. The effect of the death factor was observed in some periods, leading to non-stability. To confirm the theore

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Publication Date
Sat Jan 24 2026
Journal Name
Journal Of Stomatology
Association of modifiable and non-modifiable risk factors with periodontal disease in Iraqi individuals: a retrospective study
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Introduction Periodontal diseases are ranked among the most common health problems affecting mankind. These conditions are initiated by bacterial biofilm, which is further modulated by several risk factors. Objectives To investigate the association of different risk factors with periodontal...

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Publication Date
Sat Jun 01 2019
Journal Name
Collegian
Medication adherence and predictive factors in patients with cardiovascular disease: A comparison study between Australia and Iraq
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Publication Date
Wed Jun 11 2008
Journal Name
Journal Of Al-nahrain University
ANALYSIS OF A MOLECULAR DYNAMICS SIMULATION OF THE ACETYLCHOLINESTERASE ENZYME AND ITS COMPLEX WITH (AXILLARIDINE-A) INHIBITOR
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Molecular dynamics (MD) simulations were carried out in order to investigate the binding mode of axillaridine-A at the active site of human acetylcholinesterase (AChE) enzyme. 2.0 nanosecond of MD simulations was made for the protein and the complex to dynamically explore the active site and the behavior of the ligand at the peripheral AChE binding site. These calculations for the enzyme alone showed that the active site of AChE is located at the bottom of a deep and narrow cavity whose surface is lined with rings of aromatic residues and Tyr72 is almost perpendicular to the Trp286 ring and forms a stable - interaction. The size of the active site of the complex decreases with time due to increase the interaction. Axillaridine-A forms

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