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Thermal performance of a flat-plate solar collector using aqueous colloidal dispersions of graphene nanoplatelets with different specific surface areas
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The effects of using aqueous nanofluids containing covalently functionalized graphene nanoplatelets with triethanolamine (TEA-GNPs) as novel working fluids on the thermal performance of a flat-plate solar collector (FPSC) have been investigated. Water-based nanofluids with weight concentrations of 0.025%, 0.05%, 0.075%, and 0.1% of TEA-GNPs with specific surface areas of 300, 500, and 750 m2/g were prepared. An experimental setup was designed and built and a simulation program using MATLAB was developed. Experimental tests were performed using inlet fluid temperatures of 30, 40, and 50 °C; flow rates of 0.6, 1.0, and 1.4 kg/min; and heat flux intensities of 600, 800, and 1000 W/m2. The FPSC’s efficiency increased as the flow rate and heat flux intensity increased, and decreased as inlet fluid temperature increased. When using nanofluids in the FPSC, the measured temperatures of absorber plate and tube wall decreased down to 3.35% and 3.51%, respectively, with the increase in weight concentration and specific surface area, while the efficiency increased up to 10.53% for 0.1- wt% TEA-GNPs nanofluid with specific surface area of 750 m2/g, in comparison with water. When using water as heat transfer fluid, very good agreement was obtained between the experimental and predicted values of absorber plate temperature, tube wall temperature, and collector’s efficiency with maximum differences of 3.02%, 3.19%, and 3.26%, respectively. While, when using nanofluids, higher differences were found, up to 4.74%, 4.7%, and 13.47% for TEA-GNPs nanofluid with specific surface area of 750 m2/g, respectively. Accordingly, the MATLAB code was capable of simulating the thermal performance of FPSCs utilizing nanofluids as their heat transfer fluids with acceptable accuracy. Values of performance index were all greater than 1, and increased as weight concentration increased up to 1.104 for 0.1- wt% TEA-GNPs nanofluid with specific surface area of 750 m2/g, implying higher positive effects on efficiency than negative effects on pressure drop. Accordingly, the investigated nanofluids can efficiently be used in FPSCs for enhanced energy efficiency, and the 0.1- wt% water-based TEA-GNPs nanofluid with specific surface area of 750 m2/g was comparatively the superior one.

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Publication Date
Fri Mar 04 2022
Journal Name
Journal Of Water Resources And Geosciences
A Review Study on Gypseous Soils Stabilized with Different Additives in Iraq
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Publication Date
Wed Nov 12 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Antibacterial effects of mineral trioxide aggregate and Biodentine TM after the addition of different concentrations of black seed aqueous solutions
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Background: Mineral Trioxide Aggregate (MTA) and BiodentineTM cements are new materials with numerous exciting clinical applications. Both have appreciable properties which include good physical properties and the ability to stimulate tissue regeneration as well as good antibacterial effects. The aim of this study was to investigate and compare the antibacterial effects of MTA and BiodentineTM, when they were mixed with different concentrations of aqueous solutions of Black Seed extract, against Enterococcus faecalis. Materials and methods: MTA and BiodentineTMwere prepared according to the manufacturer’s instructions. The method of Mawlood was followed to prepare the Black Seed aqueous solution. Agar diffusion method on Brain Heart

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Publication Date
Mon Mar 30 2009
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Purification of Zinc Oxide Using Direct Thermal Process by Petroleum Coke
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The present investigation is concerned for the purification of impure zinc oxide (80-85 wt %) by using petroleum coke
(carbon content is 76 wt %) as reducing agent for the impure zinc oxide to provide pure zinc vapor, which will be
oxidized later by air to the pure zinc oxide.
The operating conditions of the reaction were studied in detail which are, reaction time within the range (10 to 30 min),
reaction temperature (900 to 1100 oC), air flow rate (0.2 to 1 l/min) and weight percentage of the reducing agent
(petroleum coke) in the feed (14 to 30 wt %).
The best operating conditions were (30 min) for the reaction time, (1100 oC) for the reaction temperature, (1 l/min) for
the air flow rate, and (30 wt %) of reducing

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Publication Date
Thu Apr 29 2021
Journal Name
Egyptian Journal Of Chemistry
Fabrication and Study of ZnO thin Films using Thermal Evaporation Technique
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Pure SnSe thin film and doped with S at different percentage (0,3,5,7)% were deposited from alloy by thermal evaporation technique on glass substrate at room temperature with 400±20nm thickness .The influences of S dopant ratio on characterization of SnSe thin film Nano crystalline was investigated by using Atomic force microscopy(AFM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), Hall Effect measurement, UV-Vis absorption spectroscopy to study morphological, structural, electrical and optical properties respectively .The XRD showed that all the films have polycrystalline in nature with orthorhombic structure, with preferred orientation along (111)plane .These films was manufactured of very fine crystalline size in the ra

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Publication Date
Thu Nov 21 2019
Journal Name
Journal Of Engineering
Thermal Buckling of Angle-Ply Laminated Plates Using New Displacement Function
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ABSTRACT

Critical buckling temperature of angle-ply laminated plate is developed using a higher-order displacement field. This displacement field used by Mantari et al based on a constant ‘‘m’’, which is determined to give results closest to the three dimensions elasticity (3-D) theory. Equations of motion based on higher-order theory angle ply plates are derived through Hamilton, s principle, and solved using Navier-type solution to obtain critical buckling temperature for simply supported laminated plates. Changing (α2/ α1) ratios, number of layers, aspect ratios, E1/E2 ratios for thick and thin plates and their effect on thermal

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Publication Date
Thu Mar 01 2018
Journal Name
Journal Of Engineering
Numerical Investigation of the Effect of Inserted Twisted Tape inside Submerged Bundle Tubes on its Thermal Performance
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Twisted tape insertion in smooth plain tube is one of types of passive methods that is used to enhance heat transfer. Swirl fluid flow inside tube and related heat transfer characteristics are very complex. ANSYS FLUENT (V 16.1) and ASPEN industrial program are used in analyzing this technique for enhancement heat transfer. A circular plain tube has length L=8534mm and 17 mm inner diameter with twisted tape has twist ratio of y = (H/D) = (150/17) =8.8 along with a plain tube were considered for this study. Eight Reynolds numbers (Re) of 784, 1000, 2000, 3000, 4000, 5000, 6000 and 7000 are used to analyze the response of thermal performance. Crude oil API 28 exit temperature, film heat transfer coefficient, Nusselt number

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Crossref
Publication Date
Fri Jun 29 2018
Journal Name
Journal Of Engineering
Numerical Investigation of the Effect of Inserted Twisted Tape inside Submerged Bundle Tubes on its Thermal Performance
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Twisted tape insertion in the smooth plain tube is one of the types of passive methods that are used to enhance heat transfer. Swirl fluid flow inside the tube and related heat transfer characteristics are very complex. ANSYS FLUENT (V 16.1) and ASPEN industrial program are used in analyzing this technique for enhancement heat transfer. A circular plain tube has length L=8534mm and 17 mm inner diameter with a twisted tape of twist ratio of y = (H/D) = (150/17) =8.8 along the plain tube were considered for this study. Eight Reynolds numbers (Re) of 784, 1000, 2000, 3000, 4000, 5000, 6000 and 7000 are used to analyze the response of thermal performance. Crude oil API 28 exit temperature, film heat transfer coefficient, Nus

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Crossref
Publication Date
Fri Dec 31 2021
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
EFFECT OF LOCAL HONEY PRODUCTION AREAS ON ITS CONTENT OF SOME HEAVY METALS: EFFECT OF LOCAL HONEY PRODUCTION AREAS ON ITS CONTENT OF SOME HEAVY METALS
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This study was conducted to estimate some heavy metals cadmium, lead, nickel and iron in 15 samples of Iraqi honey with 3 replicates for each sample which were collected from apiaries near potential contamination areas in five Iraqi governorates, including Baghdad, Karbala, Babylon, Diyala and Salah al-Din. The atomic absorption technique was used to estimate the concentrations of heavy metals, the results showed that there were significant differences at (P≤0.05) between the concentrations of these elements in the honey samples, the highest concentrations of cadmium 0.123 mg/kg were recorded in Baghdad, near the petrochemical production complex, lead 4.657 mg/kg and nickel 0.023 mg/kg in Babylon near the power plant, iron was

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Publication Date
Sat Aug 21 2021
Journal Name
Engineering, Technology & Applied Science Research
The Response of a Highly Skewed Steel I-Girder Bridge with Different Cross-Frame Connections
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Braces in straight bridge systems improve the lateral-torsional buckling resistance of the girders by reducing the unbraced length, while in horizontally curved and skew bridges, the braces are primary structural elements for controlling deformations by engaging adjacent girders to act as a system to resist the potentially large forces and torques caused by the curved or skewed geometry of the bridge. The cross-frames are usually designed as torsional braces, which increase the overall strength and stiffness of the individual girders by creating a girder system that translates and rotates as a unit along the bracing lines. However, when they transmit the truck’s live load forces, they can produce fatigue cracks at their connection

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Publication Date
Sat Jan 01 2022
Journal Name
Aip Conference Proceedings
Theoretical calculation of the electronic current at N3 contact with TiO2 solar cell devices
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In this study, a theoretical scenario has been used to calculate the electronic current in sensitizer N3 molecule contact to TiO2 semiconductor for electrons in functional solar cells. It is known to play an important role on the compute the eficiency of solar cell. Some parameters of electronic current such as the transition energy, driving force energy, barrier height coupling overlapping values are determined. Transition energy is a necessary parameter to calculate the electronic current in solar cell with using wide polarity solvents Acetic acid, 2-Methoxyethanol, 1-Butanol, Methyl alcohol, chloroform, N,N-Dimethylacetamide and Ethyl alcohol via the quantum donor-acceptor system. Here, we show the results of transition energy can be var

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