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Stability and thermophysical properties of non-covalently functionalized graphene nanoplatelets nanofluids
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A pioneering idea for increasing the thermal performance of heat transfer fluids was to use ultrafine solid particles suspended in the base fluid. Nanofluids, synthesized by mixing solid nanometer sized particles at low concentrations with the base fluid, were used as a new heat transfer fluid and developed a remarkable effect on the thermophysical properties and heat transfer coefficient. For any nanofluid to be usable in heat transfer applications, the main concern is its long-term stability. The aim of this research is to investigate the effect of using four different surfactants (sodium dodecyl benzene sulfonate (SDBS), sodium dodecyl sulfate (SDS), cetyl trimethylammonium bromide (CTAB), and gum Arabic (GA)), each with three different concentrations, and five ultrasonication times (15, 30, 60, 90, and 120 min) on the stability of water-based graphene nanoplatelets (GNPs) nanofluids. In addition, the viscosity and thermal conductivity of the highest stability samples were measured at different temperatures. For this aim, nineteen different nanofluids with 0.1 wt% concentration of GNPs were prepared via the two-step method. An ultrasonication probe was utilized to disperse the GNPs in distilled water. UV–vis spectrometry, zeta potential, average particle size, and Transmission Electron Microscopy (TEM) were helpful in evaluating the stability and characterizing the prepared nanofluids. TEM and zeta potential results were in agreement with the UV–vis measurements. The highest nanofluid stability was obtained at 60-min ultrasonication time. The prepared water-based pristine GNPs nanofluids were not stable, and the stability was improved with the addition of surfactants. The presence of SDBS, SDS, and CTAB surfactants in the nanofluids resulted in excessive foam. The best water-based GNPs nanofluid was selected in terms of better stability, higher thermal conductivity, and lower viscosity. From all the samples that were prepared in this research, the (1–1) SDBS–GNPs sample with 60-min ultrasonication showed the highest stability (82% relative concentration after 60 days), the second better enhancement in the thermal conductivity of the base fluid (8.36%), and nearly the lowest viscosity (7.4% higher than distilled water).

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Publication Date
Sat May 01 2021
Journal Name
Journal Of Physics: Conference Series
Study The Effect of Annealing on Structural and Optical Properties of Indium Selenide (InSe) Thin Films Prepared by Vacuum Thermal Evaporation Technique
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Abstract<p>In this work, InSe thin films were deposited on glass substrates by thermal evaporation technique with a deposit rate of (2.5∓0.2) nm/sec. The thickness of the films was around (300∓10) nm, and the thin films were annealed at (100, 200 and 300)°C. The structural, morphology, and optical properties of Indium selenide thin films were studied using X-ray diffraction, Scanning Electron Microscope and UV–Visible spectrometry respectively. X-ray diffraction analyses showed that the as deposited thin films have amorphous structures. At annealing temperature of 100°C and 200°C, the films show enhanced crystalline nature, but at 300°C the film shows a polycrystalline structure with Rhombohedral phas</p> ... Show More
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Publication Date
Wed Sep 01 2021
Journal Name
Iraqi Journal Of Physics
The Thermal Properties of Gliding arc Plasma Produced by Laboratory Reverse Vortex Flow System
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A low-cost reverse flow plasma system powered by argon gas pumping was built using homemade materials in this paper. The length of the resulting arc change was directly proportional to the flow rate, while using the thermal camera to examine the thermal intensity distribution and demonstrating that it is concentrated in the centre, away from the walls at various flow rates, the resulting arc's spectra were also measured. The results show that as the gas flow rate increased, so did the ambient temperature. The results show that the medium containing the arc has a maximum temperature of 34.1 ˚C at a flow rate of 14 L/min and a minimum temperature of 22.6 ˚C at a flow rate of 6 L/min.

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Publication Date
Thu Jun 30 2022
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
THE USE OF ULTRAVIOLET RAYS TO PRESERVE FERMENTED GREEN OLIVES AND ITS EFFECTS ON CHEMICAL PROPERTIES OF ITS EXTRACTED OIL : THE USE OF ULTRAVIOLET RAYS TO PRESERVE FERMENTED GREEN OLIVES AND ITS EFFECTS ON CHEMICAL PROPERTIES OF ITS EXTRACTED OIL
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The use of ultraviolet rays is one of the methods of treating surface contamination of many foods especially pickles. however, there are some side effects to its use, especially in high percentage oil food products, it is necessary to determine the appropriate doses and time periods to avoid deterioration of its oil physicochemical characteristics. this study was conducted to see the effect of ultraviolet rays 15W on some chemical properties of olive oil when using it to preserve green olive pickles, treated for 5, 10 and 15 min daily. green olive fruits Iraqi variety (al-ashrasi), in season (2020-2021) were pickled using Spanish style, the best time period to pr

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Publication Date
Sat Oct 01 2011
Journal Name
Iraqi Journal Of Physics
The Role of Annealing Temperature on the Optical Properties of Thermally Deposited CdTe Films
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A polycrystalline CdTe film has been prepared by thermal evaporation technique on glass substrate at substrate temperature 423 K with 1.0 m thicknesses. The film was heated at various annealing temperature under vacuum (Ta =473, 523 and K). Some of physical properties of prepared films such as structural and optical properties were investigated. The patterns of X-ray diffraction analysis showed that the structure of CdTe powder and all films were polycrystalline and consist of a mixture of cubic and hexagonal phases and preferred orientation at (111) direction.
The optical measurements showed that un annealed and annealed CdTe films had direct energy gap (Eg). The Eg increased with increasing Ta. The refractive index and the real p

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Publication Date
Sun Dec 01 2019
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The role of monetary policy in the aggregate indicator of banking stability in Iraq: An applied research in the Central Bank of Iraq for the period (2010 - 2017)
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The research sought to demonstrate the effectiveness of monetary policy in banking stability by measuring the impact of monetary policy in the composite index of banking stability in Iraq for the period 2010/2017, as the stability of the financial system is one of the main objectives that the Central Bank is keen to achieve along with other objectives to ensure the performance Effective for all economic units, this is what prompted the central banks to give more attention in ensuring the safety, durability and stability of their financial systems, and the increasing interest by the Central Bank of Iraq in the subject of financial stability stems from its responsibility in ensuring a sound and stable financial system. Maintain it and mini

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Publication Date
Mon Feb 25 2019
Journal Name
Iraqi Journal Of Physics
Comparison study of CC and CH vibration frequencies and eelectronic properties for mono, Di, Tri, and tetra-rings layer of arm chair (SWCNTs)
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Semi-empirical methods were applied for calculating the vibration frequencies and IR absorption intensities for normal coordinates of the {mono (C56H28), di (C84H28), tri (C112H28) and tetra (C140H28)} -rings layer for (7,7) armchair single wall carbon nanotube at their equilibrium geometries which were all found to have D7d symmetry point group.

Assignment of the modes of vibration (3N-6) was done depending on the pictures of their modes by applying (Gaussian 03) program. Comparison of the vibration frequencies of (mono, di, tri and tetra) rings layer which are active in IR, and inactive in Ramman spectra. For C-H stretching vibrat

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Publication Date
Fri Jan 01 2021
Journal Name
Materials Today: Proceedings
Study the electronic and spectroscopic properties of ALxB7-XN7 Wurtzoids as a function of size and concentration using density functional theory
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Publication Date
Mon Feb 10 2020
Journal Name
Iraqi Journal Of Soil Sciences
Spatial Variability of Some Soil Chemical and Fertility Properties in Hydrosequences through Grain Crops Growing Areas of Najaf and Alqadissiya Provinces
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Kiffil Shinafiya project was selected as it’s been conducted and covering the areas of grain crops agriculture in Najaf and Qadissiya provinces. Lands of this project are considered as a part of the Mesopotamian plain located in between N32⁰ 15′, N31⁰ 30′ and E44⁰ 44’, E44⁰ 20′. Three hydrosequences were disclosed with three transects (T1, T2, T3) in the area of study. The first hydrosequence was perpendicular on the other two sequences. Fifteen pedons were outcropped, five pedons in each transect in addition to eighteen more surface samples to be a total samples of 33 locations. Pedons were morphologically described due to soil survey manual (Soil Survey Staff, 2017). Spatial distribution of soil salinity showed that the

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Publication Date
Fri Jan 01 2021
Journal Name
Materials Today: Proceedings
Study the electronic and spectroscopic properties of ALxB7-XN7 Wurtzoids as a function of size and concentration using density functional theory
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Electronic properties including (bond length, energy gap, HOMO, LUMO and density of state) as well as spectroscopic properties such like infrared, Raman scattering, force constant, reduced mass and longitu- dinal optical mode as a function of frequency are based on size and concentration of the molecular and nanostructures of aluminum nitride ALN, boron nitride BN and AlxB7-XN7 as nanotubes has calculated using Ab –initio approximation method dependent on density functional theory and generalized gradient approximation. The geometrical structure are calculated by using Gauss view 05 as a complementary program. Shows the energy gap of ALN, BN and AlxB7-XN7 as a function of the total number of atoms , start from smallest molecule to reached

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Publication Date
Wed Oct 23 2024
Journal Name
Polymers
Improving the Mechanical, Thermoelectric Insulations, and Wettability Properties of Acrylic Polymers: Effect of Silica or Cement Nanoparticles Loading and Plasma Treatment
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The acrylic polymer composites in this study are made up of various weight ratios of cement or silica nanoparticles (1, 3, 5, and 10 wt%) using the casting method. The effects of doping ratio/type on mechanical, dielectric, thermal, and hydrophobic properties were investigated. Acrylic polymer composites containing 5 wt% cement or silica nanoparticles had the lowest abrasion wear rates and the highest shore-D hardness and impact strength. The increase in the inclusion of cement or silica nanoparticles enhanced surface roughness, water contact angle (WCA), and thermal insulation. Acrylic/cement composites demonstrated higher mechanical, electrical, and thermal insulation properties than acrylic/silica composites because of their lowe

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