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ijs-8530
Numerical Analysis for Streamer Discharge at the Discharge Transition from the Second to the Third Mode in Transformers Oil
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     This study is a numerical analysis of the transition process from the second to the third mode in transformer oil. In this study, it was determined how to change from the second to the third mode, which is thought to be a precursor to the process of electrical breakdown, which results in a significant loss of electrical energy and harm to electrical devices and equipment. The initiation time, length, rate of propagation velocity, and radius of the streamer discharge were determined. The transition from the second to the third mode during the electrical discharge process may lead to the occurrence of an electrical breakdown, which is one of the greatest challenges facing scientists and engineers who deal with the electrical power of transmission and generation devices. The model was designed by AutoCAD software, which included two electrodes: a needle, with a tip radius of (4µm), and a plate, with a gap of (1 mm) between them. The gap between the two electrodes was filled with transformer oil. The equations, which are Poisson's equation and the continuity equations for positive and negative ions and electrons, which are generated by applying an applied voltage (from 27 kV to within 278 kV), had been solved by a simulation process. All the schematics and drawings were extracted by the Comsol Multiphysics program.

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Publication Date
Thu Aug 31 2023
Journal Name
Journal Of Molecular Modeling
Ab initio study of structural, mechanical and electronic properties of 3d transitional metal carbide in cubic rocksalt (rs), zincblende (zb), and cesium chloride (cc) structures by using LDA and GGA Approximation
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This study rigorously investigates three 3d transition metal carbide (TMC) structures via LDA and GGA approximations. It examines cohesive energy (Ecoh), Vickers hardness (Hv), mechanical stability, and electronic properties. Notably, most 3d TMCs exhibit higher cohesive energy than nitrides, and rs-TiC demonstrates a Vickers hardness of 25.66 GPa, outperforming its nitride counterpart. The study employs theoretical calculations to expedite research, revealing mechanical stability in CrC and MnC (GGA) and CrC (LDA in cc structure), while all 3d TMCs in rs and seven in zb structures show stability. Charge transfer and bonding analysis reveal enhanced covalency along the series, influenced by the interplay between p orbitals of carbon and d o

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Publication Date
Sat Oct 01 2011
Journal Name
Iraqi Journal Of Physics
Electrochemical deposition of CuInS2 thin films
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Chalcopyrite thin films were one-step potentiostatically deposited onto stainless steel plates from aqueous solution containing CuSO4, In2(SO4)3 and Na2S2O3.The ratio of (In3+:Cu2+) which involved in the solution and The effect of cathodic potentials on the structural had been studied. X-ray diffraction (XRD) patterns for deposited films showed that the suitable ratio of (In3+:Cu2+) =6:1, and suitable voltage is -0.90 V versus (Ag/AgCl) reference electrode

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Publication Date
Sun Jun 04 2017
Journal Name
Baghdad Science Journal
Electrical Dielectric Authorship of Polyvinyl-Acetate and Toluene Diisocyanate (PVA-TDI) with Manufactured Sulfonated Phenol-formaldehyde (SPF) Viscous Mass Material Composite
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The electrical insulation of the manufacture sulfonated phenol-formaldehyde viscous material (product) has been studied with Polyvinyl-acetate (PVA) and toluene diisocyanate (TDI) blend has been prepared by fixing percentage by weight 3:1 and mixed with different percentages by weight of the product sulfonated phenol formaldehyde viscous mass (SPF). The Fourier transform infrared (FTIR) spectroscopy is done on (SPF) resin powder and prepared film of PVA-TDI-SPF viscous mass. The quality factor (Q), dissipation factor (D), parallel resistance (Rp), series resistance (Rs), parallel capacitance (Cp), series capacitance (Cs) and phase shift (?) are measured. The calculated maximum dielectric constant (??) is 3.49x107 at sample (1) wt.1% SPF vis

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Publication Date
Tue Sep 25 2018
Journal Name
Iraqi Journal Of Science
Delineation of leachate plume migration by electrical resistivity methods Ile Epo dumpsite, Lagos, Southwestern Nigeria
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A 5-traverse 2D resistivity survey and 20 Vertical Electrical Sounding (VES) points were carried out on Ile Epo Dump Site with a view to inferring the extent of migration of leachate plumes in the subsurface for possible contamination of groundwater. The surveys were carried out with Omega model resistivity meter. The Schlumberger configuration was employed for the VES while Wenner configuration was employed for the 2D resistivity survey (Constant Separation Techniques). The obtained VES and CST data were interpreted using WinResist and DIPRO respectively. The integrated results revealed three to four geo-electrically polluted materials as highly saturated fills (15 Ωm, 1.9 – 27.4m), saturated fills (15 - 30 Ωm, 3.6 – 29.9m) and un

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Publication Date
Thu Apr 27 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Detection of Human Remain Using GPR Technique
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    In this work, animal bones with different shapes and sizes were used to study the characteristics of the ground penetrating Radar system wares reflected by these bones. These bones were buried underground in different depths and surrounding media. The resulting data showed that the detection of buried bones with the GPR technology is highly dependent upon the surrounding media that the bones were buried in. Humidity is the main source of signal loss in such application because humidity results in low signal-to-noise ratio which leads to inability to distinguish between the signal reflected by bones from that reflected by the dopes  in the media such as rock .

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Publication Date
Fri Jun 03 2022
Journal Name
Basra Journal Of Science
Morphological and Electrical properties of Polyvinylpyrrolidone/Multi-walled Carbon Nanotubes Nanocomposite with Graphene
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The solution casting method was used to prepare a polyvinylpyrrolidone (PVP)/Multi-walled carbon nanotubes (MWCNTs) nanocomposite with Graphene (Gr). Field Effect Scanning Electron Microscope (FESEM) and Fourier Transformer Infrared (FTIR) were used to characterize the surface morphology and optical properties of samples. FESEM images revealed a uniform distribution of graphene within the PVP-MWCNT nanocomposite. The FTIR spectra confirmed the nanocomposite information is successful with apperaring the presence of primary distinct peaks belonging to vibration groups that describe the prepared samples.. Furthermore, found that the DC electrical conductivity of the prepared nanocomposites increases with increasing MWCNT concentratio

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Publication Date
Mon May 20 2024
Journal Name
Iraqi Journal Of Applied Physics
Effect of Thermal Neutron Radiation Dose on Density of Local and Extended Energy States in Se<inf>55</inf>S<inf>20</inf>Sb<inf>15</inf>Sn<inf>10</inf> Alloy
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Four samples of the Se55S20Sb15Sn10 alloy were prepared using the melting point method. Samples B, C and D were irradiated with (6.04×1010, 12.08×1010 and 18.12×1010 (n.cm-2s -1 ) of thermal neutron beam from a neutron source (241Am-9Be) respectively, while sample A was left not irradiated. The electrical properties were assessed both before and after the radiation. All irradiated and non-irradiated samples show three conduction mechanisms, at low temperatures, electrical conductivity is achieved by electron hopping between local states near the Fermi level. At intermediate temperatures, conduction occurs by the jumping of electrons between local states at band tails. At high temperatures, electrons transfer between extended stat

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Publication Date
Mon Jan 30 2023
Journal Name
Iraqi Journal Of Science
Characteristics of Lead and Sulfur Plasma Parameters by Optical Emission Spectroscopy
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This study uses the optical emission spectroscopy (OES) technique to find the lead(Pb) and sulfur (S) plasma parameters employing a pulse of Nd: YAG laser (Q-switched 1064nm wavelength) and different laser energies of (400,500,600 and 700 mJ). The electron temperature Te (eV) is calculated using the Boltzmann-Plot method, and the electron density ne (cm-3)is determined by the Stark broadened way. Moreover, Debye length λD (cm) and plasma frequency ωp (Hz) are studied as a function of laser energy. An apparent increase was noted in the electron temperature of lead plasma and a decrease in sulfur plasma. The results also showed that each increase in the laser intensity causes an incr

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Publication Date
Wed Dec 30 2009
Journal Name
Iraqi Journal Of Physics
Preparation of Cu thin film by cylindrical magnetron sputtering device
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In the present work, a D.C. magnetron sputtering system was
designed and fabricated. This chamber of this system includes two
coaxial cylinders made from copper .the inner one used as a cathode
while the outer one used as a node. The magnetic coils located on
the outer cylinder (anode) .The profile of magnetic field for various
coil current (from 2Amp to 14Amp) are shown. The effect of
different magnetic field on the Cu thin films thickness at constant
pressure of 7x10-5mbar is investigated. The result shown that, the
electrical behavior of the discharge strongly depends on the values
of the magnetic field and shows an optimum value at which the
power absorbed by the plasma is maximum. Furthermore, the
pl

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Publication Date
Fri Dec 30 2022
Journal Name
Iraqi Journal Of Science
Regeneration of Engine Used Oils by Solvent Extraction
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    The regeneration of used oil is one of the essential processes for economical, industrial and environmental targets. Used oil is rich of hydrocarbons, metals (such as: aluminium, chromium, copper, iron, lead, manganese, nickel, silicon and tin), gasoline, water and antifreeze. Due to the high increasing rate of the number of cars, there is a huge quantity of used oil. In this study, different brands of used oil were involved in extraction and adsorption processes as a regeneration process of these used oils. The optimum conditions were determined such as solvents composition, solvent: oil ratio, KOH concentration and temperature. The solvent mixture of 40% of petroleum ether, 11% of 1-butanol and 4% of 2-propanol has shown the bes

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