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alkej-631
Free Convective Heat Transfer with Different Sections Lengths Placed at the Exit of a Vertical Circular Tube subjected to a Constant Heat Flux
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A free convective heat transfer from the inside surface of a uniformly heated vertical circular tube has been experimentally investigated under a constant wall heat flux boundary condition for laminar air flow in the ranges of RaL from 6.9108 to 5109. The effect of the different sections (restrictions) lengths placed at the exit of the heated tube on the surface temperature distribution, the local and average heat transfer coefficients were examined. The experimental apparatus consists of aluminum circular tube with 900 mm length and 30 mm inside diameter (L/D=30). The exit sections (restrictions) were included circular tubes having the same inside diameter as the heated tube but with different lengths of 600 mm (L/D=20), 900 mm (L/D=30), 1200 mm (L/D=40), 1500 mm (L/D=50), and 1800 mm (L/D=60). It was found that the surface temperature along the tube axial distance would be higher for restriction with length of 1800 mm (L/D=60) and it would be smaller for the restriction with length of 1200 mm (L/D=40). The results show that the local Nux and average Nusselt number were higher values for the restriction with length of 1200 mm (L/D=40) and smaller values for the restriction with length of 1800 mm (L/D=60). The results were correlated with empirical equations and presented as Logagainst Log for each case investigated and a general empirical equation was proposed for all cases.

 

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Publication Date
Tue Nov 25 2025
Journal Name
Inorganic Chemistry Communications
Synthesis, spectroscopic and single-crystal analysis, and DFT studies of N₂O₂ diamine coordination complexes: solvent-driven geometry switching and NLO properties
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The design of coordination compounds with solvent-responsive optical properties remains a central challenge in molecular photonics. Here, we describe the synthesis and full characterisation of a symmetrical tetradentate diamine ligand, 3,3′-((1,2-phenylenebis(azanediyl))- bis(methanylylidene))bis(pentane-2,4-dione) (H₂L), and its neutral square-planar complexes [M(L)] (M(II) = Co, Ni, Cu). The Cu(II) complex crystallised as [Cu(L)]⋅0.5 (pyrazine), adopting a nearly square-planar geometry (τ₄ = 0.06) in the solid state, as confirmed by single-crystal X-ray diffraction. In DMSO solution, UV–Vis spectra revealed reversible axial coordination of two solvent molecules, driving a transformation to a distorted octahedral geometry. Struc

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Publication Date
Mon Sep 23 2024
Journal Name
Journal Of Inorganic And Organometallic Polymers And Materials
Quaternary Biocomposite of Chitosan-Polyvinyl Alcohol/Food Grade Algae/ Montmorillonite Clay for Cationic Methyl Violet 2B Dye Removal: Optimization and Desirability Functions
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Publication Date
Sat May 01 2021
Journal Name
Journal Of Physics: Conference Series
Metal Complexes of Multidentate N<sub>2</sub>S<sub>2</sub> Heterocyclic Schiff-base Ligands;Formation, Structural Characterisation and Biological Activity
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Abstract<p>The synthesis of ligands with N<sub>2</sub>S<sub>2</sub> donor sets that include imine, an amide, thioether, thiolate moieties and their metal complexes were achieved. The new Schiff-base ligands; N-(2-((2,4-diphenyl-3-azabicyclo[3.3.1]nonan-9-ylidene)amino)ethyl)-2-((2-mercaptoethyl)thio)-acetamide (H<sub>2</sub>L<sup>1</sup>) and N-(2-((2,4-di-p-tolyl-3-azabicyclo[3.3.1]nonan-9-ylidene)amino)ethyl)-2-((2-mercaptoethyl)thio) acetamide (H2L<sup>2</sup>) were obtained from the reaction of amine precursors with 1,4-dithian-2-one in the presence of triethylamine as a base in the CHCl3 medium. Complexes of the general formula K<sub>2<</sub></p> ... Show More
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Publication Date
Thu Jan 01 2009
Journal Name
Ibn Al-haitham Journal For Pure And Applied Science
Complexeation Behavior of CoII, NiII, CuII, ZnII, and CdII Ions Toward Schiff Base Derived From 2, 4-Dihydroxy Benzaldehyde and O-Phenylene Diamin
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The aim of this work covers the synthesis and characterization of the new tertra dentate ligand (H4L) containing (N and O) as donor set atoms kind (N2O2) where: H4L=Bis-1,2 (2,4- dihydroxybenzylediene phylinediamine . The preparation of ligand contains reaction 2, 4 - Dihydroxy benzaldehyde and o-phenylene diamine . Schiff base was reacted with some metal ions in the presence of methanol to give the complexes in the general formula [M (H2L)] where: MII = Co, Ni, Cu, Zn, Cd. All compounds were characterized by spectroscopic methods I.R , U.V.-Vis, metal content and molar conductivity measurements, showed that the complexes are non-electrolyte. The proposed geometry for all of the proposed complexes was a tetrahedral while Ni complex was squa

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Publication Date
Fri Jun 01 2018
Journal Name
Journal Of The College Of Languages (jcl)
ЯВЛЕНИЯ ПОЛИСЕМИИ И ОМОНИМИИ В СПЕЦИАЛИЗИРОВАННОЙ ТЕРМИНОСИСТЕМЕ (на материале геодезической терминологии) Homonymy and Polysemy in Technical Terminology: Terms of Geodesy as an Example
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Aннотация

В статье представлены явления полисемии и омонимии в специализированной терминосистеме, а именно в геодезической терминологии; определены предпосылки и причины возникновения полисемии и омонимии в профессиональном языке в области геодезии и кадастра; установлены различия и взаимосвязь между понятиями омонимия и полисемия; выделены главных типы полисемантических тер

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Publication Date
Thu Nov 01 2012
Journal Name
Iraqi Postgraduate Medical Journal
Lactic Acid 5% Mouthwash is an Effective Therapeutic and Prophylactic Agent in Treatment of Recurrent Aphthous Ulcer (Single blind placebo controlled therapeutic study)
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KE Sharquie, SA Al Mashhadani, AA Noaimi, RK Al-Hayani, SA Shubber, Iraqi Postgraduate Medical Journal, 2012 - Cited by 1

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Publication Date
Wed Aug 28 2019
Journal Name
International Journal Of Drug Delivery Technology
Synthesis, Characterization and Screening their Antibactrial Activity of some New Oxazepine and Diazepine Compounds Containing 1,3,4-Oxadiazole Ring Derived from L-Ascorbic Acid
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The search involve the synthesis of some new 1,3-oxazepine and 1,3-diazepine derivatives were synthesized from Schiff base. The Schiff base (VIII) prepared from reaction of aldehyde (IV) derived from L-ascorbic acid with aromatic amine ([2-(4- nitrophenyl)-5-(4-aminophenyl)-1,3,4-oxadiazole] (VII). Oxazepine compounds (IX-XI) were synthesized from the cyclic condensation of Schiff base (VIII) with (maleic, phthalic and 3-nitrophthalic) anhydride, compounds (IX-XI) that were reacted with p-methoxyaniline to give diazepine derivatives (XII-XIV). The structures of the new synthesized compounds have been confirmed by physical properties and spectroscopy measurements such as FTIR, and some of them by 1 H-NMR, 13 CNMR, Mass, and evaluated

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Publication Date
Wed Nov 01 2017
Journal Name
Iraqi Journal Of Community Medicine
Zinc Sulphate 5% Mouthwash is an Effective Therapeutic and Prophylactic Agent in Treatment of Recurrent Aphthous Ulcer (Single blind placebo controlled therapeutic study).
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KE Sharquie, SA Al-Mashhadani, A A Noaimi, RK Al-Hayani, SA Shubber, Iraqi Journal of Community Medicine, 2017 - Cited by 1

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Publication Date
Fri Jun 10 2022
Journal Name
V. International Scientific Congress Of Pure, Applied And Technological Sciences
Synthesis and characterisation of new Co(II), Zn(II) and Cd(II) complexes derived from oxadiazole ligand and 1,10-phenanthroline as co-ligand
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SYNTHESIS AND CHARACTERISATION OF NEWCo(II), Zn(II) AND Cd(II) COMPLEXES DERIVED FROM OXADIAZOLE LIGAND AND 1,10-PHENANTHROLINE AS Co-LIGAND

Publication Date
Sat Aug 09 2025
Journal Name
Oxidation Communications
SYNTHESIS AND SPECTRAL CHARACTERISATION, MOLECULAR DOCKING, AND ANTIOXIDANT ACTIVITIES OF NOVEL METAL COMPLEXES AND THEIR NANOCOMPLEXES DERIVED FROM AN ISATIN-BASED SCHIFF BASE
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