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Heat Transfer Characteristics of a Fluid Flow in Multi Tube Heat Exchanger Fitted with Perforated Fins
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The heat transfer and flow resistance characteristics for air flow cross over circular finned tube heat exchanger has been studied numerically and experimentally. The purpose of the study was to improve the heat transfer characteristics of an annular finned-tube heat exchanger for better performance. The study has concentrated on the effect of the number of perforations and perforations shapes on the heat transfer and pressure drop across a staggered finned tube heat exchanger. The Numerical part of present study has been performed using ANSYS Fluent 14.5 using SST Turbulent model, while the experimental study consist from a test rig with different models of heat exchangers and all required measurement devices were building up to cover the experimental work for the range of Reynolds number (7500-17500). The experimental results show that average Nusselt number of the six circular perforations fins model is about 11.08 % higher than that for solid fin model and with triangular perforations model is about 10.12 % higher than that for the solid fin. Triangular perforation finned heat exchanger model gives  a best result than the other models due to excessive increment in the )Nu( in comparison with other models take in consideration pressure drop. The results were validated with previous work and the comparison between the experimental and numerical shows a good agreement with a maximum deviation ±10% between them.

 

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Publication Date
Sun Jun 01 2014
Journal Name
Baghdad Science Journal
Solution of Nonlinear High Order Multi-Point Boundary Value Problems By Semi-Analytic Technique
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In this paper, we present new algorithm for the solution of the nonlinear high order multi-point boundary value problem with suitable multi boundary conditions. The algorithm is based on the semi-analytic technique and the solutions are calculated in the form of a rapid convergent series. It is observed that the method gives more realistic series solution that converges very rapidly in physical problems. Illustrative examples are provided to demonstrate the efficiency and simplicity of the proposed method in solving this type of multi- point boundary value problems.

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Publication Date
Mon Jun 27 2022
Journal Name
. J Pharm Negative Results
Synthesis, Antioxidant, antibacterial and docking structure of new dihydro-pyrimidine derivatives containing multi phenol
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Newly series of 6,6’-((2-(Aryl)dihydropyrimidine-1,3(2H,4H)-diyl)bis(methylene))bis(2-methoxy phenol) (3a-i) were synthesized from cyclization of 6,6’-((propane-1,3-diylbis (azanediyl)) bis(methylene)) bis(2-methoxyphenol) with several aryl aldehyde in the presence of acetic acid. The newly compounds characterized from their IR, NMR and EIMs spectra. The antioxidant capacity of these compounds screened by utilizing DPPH and FRAP assays. Compounds 3g and 3i exhibited significant antioxidant capability in both assays. Docking study for these compounds as a potential inhibitors of gyrase enzyme were carried out. Compound 3g exhibited significant inhibition with binding free energies (DG) higher than novobiocin. compounds 2, 3a, 3b, 3

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Scopus (4)
Scopus
Publication Date
Tue Dec 13 2022
Journal Name
Mathematical Modelling Of Engineering Problems
Dynamic Response and Reliability Analysis of Stochastic Multi-Story Frame Structures under Random Excitation
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In earthquake engineering problems, uncertainty exists not only in the seismic excitations but also in the structure's parameters. This study investigates the influence of structural geometry, elastic modulus, mass density, and section dimension uncertainty on the stochastic earthquake response of a multi-story moment resisting frame subjected to random ground motion. The North-south component of the Ali Gharbi earthquake in 2012, Iraq, is selected as ground excitation. Using the power spectral density function (PSD), the two-dimensional finite element model of the moment resisting frame's base motion is modified to account for random ground motion. The probabilistic study of the moment resisting frame structure using stochastic fin

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Publication Date
Sun Jun 01 2014
Journal Name
Journal Of Economics And Administrative Sciences
Estimation the reliability function of multi state system by using Direct Partial Logic Derivative
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In this research is estimated the function of reliability dynamic of multi state systems  and their compounds and for three types of systems (serial, parallel, 2-out-of-3) and about two states (Failure and repair) depending on calculating the structur function allow to describing the behavior of

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Publication Date
Sun Dec 01 2019
Journal Name
Regenerative Therapy
In vitro periodontal ligament cell expansion by co-culture method and formation of multi-layered periodontal ligament-derived cell sheets
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Objective: Per-implantitis is one of the implant treatment complications. Dentists have failed to restore damaged periodontium by using conventional therapies. Tissue engineering (stem cells, scaffold and growth factors) aims to reconstruct natural tissues. The paper aimed to isolate both periodontal ligament stem cells (PDLSCs) and bone marrow mesenchymal stem cells (BMMSCs) and use them in a co-culture method to create three-layered cell sheets for reconstructing natural periodontal ligament (PDL) tissue. Materials and methods: BMMSCs were isolated from rabbit tibia and femur, and PDLSC culture was established from the lower right incisor. The cells were co-cultured to induce BMMSC differentiation into PDL cells. Cell morphology, stem cel

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Publication Date
Sun Jan 01 2023
Journal Name
Journal Of Pakistan Association Of Dermatologists
The role of epigenetics in immunosuppression in patients with infectious diseases as a fascinating applied observation
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Scopus (2)
Scopus
Publication Date
Sun Jan 01 2023
Journal Name
International Journal Of Research In Social Sciences & Humanities
HRM Management Approaches, With a Focus on Employee Centric Approach: A Case Study In The Rafidain Bank In Iraq
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This research attempts to shed light on a topic that is considered one of the most important topics of HRMs management, which is the Employee centric approach by examining its philosophy and understanding . To achieve the goal, the research relied on the philosophical analytical method, which is one of the approaches used in theoretical studies. The research reached a set of conclusions, the most important of which are the theoretical studies that addressed this entry in the English language and the lack of it in the Arabic language, according to the researcher's knowledge. The research reached a set of recommendations, the most important of which was that this approach needs more research, analysis and study at the practical and th

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Crossref
Publication Date
Mon Mar 01 2021
Journal Name
Iraqi Journal Of Physics
Studying of Plasma- Polymerized Pyrrole at Variable Gas Flow Rates Via Plasma Jet
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     In this manuscript has investigated the synthesis of plasma-polymerized pyrrole (C4H5N) nano-particles prepared by the proposed atmospheric pressure nonequilibrium plasma jet through the parametric studies, particularly gas flow rate (0.5, 1 and 1.5 L/min). The plasma jet which used operates with alternating voltage 7.5kv and frequency 28kHz. The plasma-flow characteristics were investigated based on optical emission spectroscopy (OES). UV-Vis spectroscopy was used to characterize the  oxidization  state for polypyrrole. The major absorption appears around 464.1, 449.7 and 435.3  nm at the three flow rate of argon gas. The chemical composition and structural properties of the

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Publication Date
Sun Jun 07 2015
Journal Name
Baghdad Science Journal
Flow Injection Spectrophotometric Determination of Thymol using 4-Aminoantipyrine and Copper(II) Nitrate
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Flow-injection (FI) spectrophotometric method has been developed for the analysis of thymol in pharmaceutical preparations. The method is based on organic coupling reaction between thymol and 4-amino antipyrine in the presence of alkaline medium to form an intense stable red color complex with copper nitrate that has a maximum absorption at 490 nm. Optimum conditions for determination of the drug was investigated .The calibration graph was linear over the range of 5-500 µg.ml-1 of thymol . The limit of detection (LOD) and limit of quantification (LOQ) were 1.81 ?g mL-1 and 3.60 ?g mL-1 respectively .The proposed method was applied satisfactorily to the determination of thymol in mouth wash preparations. The procedure is characterized by

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Crossref (1)
Crossref
Publication Date
Sat Jan 01 2011
Journal Name
Journal Of Engineering
THE EFFECTS OF BLOOD REHEOLOGICAL ON THE FLOW THROUGH AN AXISYMMETRIC ARTERIAL STENOSIS
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The prediction of the blood flow through an axisymmetric arterial stenosis is one of the most important aspects to be considered during the Atherosclrosis. Since the blood is specified as a non-Newtonian flow, therefore the effect of fluid types and effect of rheological properties of non-Newtonian fluid on the degree of stenosis have been studied. The motion equations are written in vorticity-stream function formulation and solved numerically. A comparison is made between a Newtonian and non-Newtonian fluid for blood flow at different velocities, viscosity and Reynolds number were solved also. It is found that the properties of blood must be at a certain range to preventing atheroscirasis

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