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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
Sun Sep 08 2024
Journal Name
Al Rafidain Journal Of Engineering Sciences
Oscillating Heat Pipe Start-up and Flow Characteristics with Water as Working Fluid
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Thermal management has grown more and more problematic as electronic components continue to get faster and smaller. One of the passive two-phase cooling systems are Oscillating heat pipe (OHP) that have the capacity to transmit a significant quantity of thermal energy across long distances. Oscillating heat pipe is a device that has the potential to satisfy this developing requirement. An investigation into the effects of orientation, filling ratio, and heat load on the initiation and characteristics of oscillatory motion, combining numerical simulations with experimental validation. A copper tube with a 2 mm inner diameter and a 2 mm wall thickness is used to fabricate the OHP. The condenser, evaporator, and adiabatic sections are

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Publication Date
Sun Dec 01 2019
Journal Name
Al-nahrain Journal Of Science
Adsorption of P-Aminodiphenylamine with Iodine Charge Transfer Complex on Surface Arundo Plant
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charge transfer complex formed by interaction between the p- aminodiphenylamine (PADPA) as electron donor with iodine as electron acceptor in ethanol at 250C as evidenced by color change and absorption. The spectrum obtained from complex PADPA – Iodine shows absorptions bands at 586 nm. All the variables which affected on the stability of complex were studies such as temperature, pH, time and concentration of acceptor. The linearity of the method was observed within a concentration rang (10–165) mg.L-1 and with a correlation coefficient (0.9996), while the molar absorbitivity and sandell sensitivity were (4643.32) L.mol-1.cm-1 and (0.0943) μg.cm-2, respectively. The adsorption of complex PADPA–I2 was studied using adsorbent surfaces

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Publication Date
Fri Dec 07 2018
Journal Name
Iraqi Journal Of Pharmaceutical Sciences ( P-issn 1683 - 3597 E-issn 2521 - 3512)
Effects of Aldosterone, Osteoprotegerin and Fibroblast Growth Factor-23 and Some Biochemical Markers in Chronic Kidney Disease Patients (Stage II-IV) among Patients with or without Cardiovascular Events
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Chronic Kidney Disease (CKD) is a public health problem and many studies support the link between kidney dysfunction and cardiovascular events.  Aldosterone has been shown for decades that a plasma aldosterone concentration is elevated in CKD. Whilst, Osteoprotegerin (OPG), after its capacity to protect bone, also osteoprotegerin is elevated in patients with chronic kidney disease (CKD), where it could predict the deterioration of kidney function, cardiovascular, vascular events and all-cause mortality. On the other hand, fibroblast growth factors (FGFs), in patients with CKD, its levels seem to increase progressively as kidney function worsens. The aim of the present study is to assess the correlations between serum osteoprotegerin

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Publication Date
Thu Mar 30 2017
Journal Name
Iraqi Journal Of Pharmaceutical Sciences ( P-issn 1683 - 3597 E-issn 2521 - 3512)
Proceeding Bromometric Phenol Assay without Starch Indicator
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         In this research, we exclude starch indicator preparation,that is  used in official phenol assay method. The liberated iodine, in presence of chloroform, was acting as indicator and titrated with sodium thiosulfate until getting a sharp colorless end point. Similarly, starch was cancelled during both blank and standardization of bromine water solution experiments needed in phenol assay. The results obtained were the same volumes and weights as that achieved using starch with just about 0.03% difference in sample procedure. Finally, this work will enable us to save time, effort, fuel and materials spended in laboratory.

Key word:- Phenol, assay, starch indicator

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Publication Date
Thu Oct 20 2022
Journal Name
Nano Biomedicine And Engineering
DFT-Quantum Chemical and Experimental Studies of a New 2-(Substituted Thio) Furan as a Corrosion Inhibitor in Acidic Media
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The corrosion inhibiting properties of the new furan derivative 5-(furan-2-ylmethylsulfonyl-4-phenyl-2,4- dihydro [1,2,4] triazole-3-thione in acidic solution (1.0 M HCl) were explored utilizing electrochemical, surface morphology (AFM), and quantum chemical calculations approaches. The novel furan derivative 5-(furan-2-ylmethylsulfonyl-4-phenyl-2,4- dihydro [1,2,4] triazole-3-thione shows with an inhibitory efficiency value of 99.4 percent at 150 ppm, carbon steel corrosion in acidic medium is effectively inhibited, according to the results. The influence of temperature on corrosion prevention was studied using adsorption parameters and activation thermodynamics. The novel furan derivative creates a protective layer over the metallic surfa

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Publication Date
Thu Sep 01 2016
Journal Name
Journal Of Saudi Chemical Society
Synthesis and investigation of thermal properties of vanadyl complexes with azo-containing Schiff-base dyes
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Azo-Schiff base compounds (L1 and L2) have been synthesized from the reaction of m-hydroxy benzoic acid with 1,5-dimethyl-3-[2-(5-methyl-1H-indol-3-yl)-ethylimino]-2-phenyl-2,3- dihydro-1H-pyrazol-4-ylamine and with 3-[2-(1H-indol-3-yl)-ethylimino]-1,5-dimethyl-2-phenyl- 2,3-dihydro-1H-pyrazol-4-ylamine. The free ligands and their complexes were characterized based on elemental analysis, determination of metal, molar conductivity, (1H, 13C) NMR, UV–vis, FT-IR, mass spectra and thermal analysis (TGA). The molar conductance data revealed that all the complexes are non-electrolytes. The study of complex formation via molar ratio in DMF solution has been investigated and results were consistent to those found in the solid complexes with a rat

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Publication Date
Sat Dec 31 2022
Journal Name
Mathematical Modelling Of Engineering Problems
Experimental and Numerical Study of Open Channel Flow with T-Section Artificial Bed Roughness
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Experimental and numerical studies have been conducted on the effects of bed roughness elements such as cubic and T-section elements that are regularly half-channel arrayed on one side of the river on turbulent flow characteristics and bed erosion downstream of the roughness elements. The experimental study has been done for two types of bed roughness elements (cubic and T-section shape) to study the effect of these elements on the velocity profile downstream the elements with respect to different water flow discharges and water depths. A comparison between the cubic and T-section artificial bed roughness showed that the velocity profile downstream the T-section increased in smooth side from the river and decrease in the rough side

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Publication Date
Sat Feb 18 2023
Journal Name
Luminescence
Online column preconcentration for speciation and selective determination of Cr(III) in natural water samples using flow injection with chemiluminescence detection
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Abstract<p>A simple, rapid, sensitive and inexpensive approach is described in this work based on a combination of solid‐phase extraction of 8‐hydroxyquinoline (8HQ), for speciation and preconcentration of Cr(III) and Cr(VI) in river water, and the direct determination of these species using a flow injection system with chemiluminescence detection (FI–CL) and a 4‐diethylamino phenyl hydrazine (DEAPH)–hydrogen peroxide system. At different pH, the two forms of chromium [Cr(III) and Cr(VI)] have different exchange capacities for 8HQ, therefore two columns were constructed; the pH of column 1 was adjusted to pH 3 for retaining Cr(III) and column 2 was adjusted to pH 1 for retaining of Cr(VI). The sorbe</p> ... Show More
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Publication Date
Wed Mar 29 2017
Journal Name
Iraqi Journal Of Pharmaceutical Sciences ( P-issn 1683 - 3597 E-issn 2521 - 3512)
The Correlation between Serum Total Adiponectin and Hemoglobin in Type 2 Diabetic Patients without Microalbuminuria
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Low serum total adiponectin is associated with a high incidence of type 2 diabetes or coronary artery disease in the general population. Paradoxically, serum total adiponectin is elevated in patients with chronic kidney disease (CKD), such as overt diabetic nephropathy. The current study aimed to investigate whether or not  anemia to be dependently associated with serum level of total adiponectin in  non-albuminuric male patients with type 2 diabetes . The study included 42 type 2 diabetic male patients. Anemia was defined as hemoglobin (Hb) below 14.0g/dL. All the patients were without microalbuminuria, to exclude diabetic nephropathy. The diabetic patients were divided into 2 groups according to the hemoglobin level in ad

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Publication Date
Thu Apr 01 2010
Journal Name
Journal Of Engineering
NUMERICAL AND EXPERIMENTAL INVESTIGATIONOF STEAM FILM CONDENSATION ON A VERTICAL TUBE
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 Film condensation of steam on a vertical tube is investigated numerically and experimentally,   in the present work. A mathematical model was set based on the basic conservation laws of mass   and energy, Nusselts analysis of film condensation, and empirical equations available in the   literature. Then, a simulation program in FORTRAN language was developed which simulates the   film condensation of steam on a vertical tube. A complete steam tables subprogram was also   developed and incorporated with the main program. The experimental work was carried out using a   steam condensation test bench. The inlet and outlet cooling water temperatures, steam temperature   and pressure, tube surface temperature at center, and co

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