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Investigation of Thermal Stress Distribution in Laser Spot Welding Process
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The objective of this paper was to study the laser spot welding process of low carbon steel sheet. The investigations were based on analytical and finite element analyses. The analytical analysis was focused on a consistent set of equations representing interaction of the laser beam with materials. The numerical analysis based on 3-D finite element analysis of heat flow during laser spot welding taken into account the temperature dependence of the physical properties and latent heat of transformations using ANSYS code V.10.0 to simulate the laser welding process. The effect of laser operating parameters on the results of the temperature profile were studied in addition to the effect on thermal stresses  and dimensions of the laser welded workpiece which showed good correlations between analytical and numerical results. It was found that the temperature gradients during laser welding are usually very large and it was viewed that very high temperature at the center of the workpiece, and is decreased very significantly as propagating along the radial direction. Also it found that the thermal residual stresses around the laser spot due to plastic strains were very small and localized within 1.0 mm range. It is concluded that the laser welding process is effective to reduce the welding residual stress. The stresses along the lateral direction of the workpiece changed from compression at the spot under the laser beam and tension away from the spot at the end of welding to tension at the spot under the laser beam and compression away from the spot when it cooled, which are in a good agreement with the published results.

   

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Publication Date
Mon Dec 05 2022
Journal Name
Baghdad Science Journal
Investigation of the Electron Coefficients of (Ar, He, N2, O2) Gases in the Ionosphere
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In this study, the electron coefficients; Mean energy , Mobility and Drift velocity  of different gases  Ar, He, N2 and O2  in the  ionosphere have been calculated using BOLSIG+ program to check the solution results of Boltzmann equation results, and effect of reduced electric field (E/N) on electronic coefficients. The electric field has been specified in the limited range 1-100 Td. The gases were in the ionosphere layer at an altitude frame 50-2000 km. Furthermore, the mean energy and drift velocity steadily increased with increases in the electric field, while mobility was reduced. It turns out that there is a significant and obvious decrease in mobility as a result of inelastic collisions and in addition lit

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Scopus (2)
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Publication Date
Tue Jun 14 2005
Journal Name
Iraqi Journal Of Laser
Microstructural Characterization of Rapidly Solidified Laser Clad Layers Manufactured by Laser Processing of Inconel 617
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The microstructures of rapidly solidified laser clad layers of laser cladding of Inconel 617 with different nickel-aluminum premixed clad powders are discussed. The effect of different cladding speeds on the microstructures of rapidly solidified laser clad layers is discussed too. The detailed microstructural results showed that different growth mechanisms are produced during rapid solidification. These are planar, cellular, cellular/dendritic and dendritic.

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Publication Date
Sun Jun 01 2014
Journal Name
Baghdad Science Journal
Ecological and Geographical distribution of species and genera of Primulaceae in Iraq
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The present research deal with ecological and geographical distribution of species and genera of Primulaceae in Iraq. The results were revealed that species distributed in the north , north-east and west of Iraq. Anagallis arvensis L. is the most prevalent species tolerant to different environmental conditions, while the species of Primula L. characterized as less widespread and limited in one District. In addition, the districts Rawanduz (MRO) and Sulaymaniyah (MSU) have ranked first in distribution of the species on geographical districts with (75%), while the districts southern desert (DSD) and Basra (LBA) in last place with (16.7%). Maps for geographical distribution for all species were illustrated.

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Crossref
Publication Date
Thu Feb 07 2019
Journal Name
Iraqi Journal Of Laser
In Growing Toenail Treatment using Carbon Dioxide Laser
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An ingrowing toenail is a common problem affecting mainly adolescents and young adults, with a male predominance of 3:1. The disorder generally occurs in big toes. It is painful and often chronic and it affects work and social activities. Most patients initially complain of pain and later discharge, infection and difficulty in walking occur. The Objectives: The purpose of the study was to evaluate the efficacy and safety of (10600nm) CO2 laser in the treatment of ingrowing toe nail. Patients, Materials & Methods: This study was done in laser medicine research clinics from July 2013 to the end of December 2013; 10 patients including 7(70%) males and 3 (30%) females with age ranging from 18 years to 70 years with mean age of 44 years o

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Publication Date
Tue Oct 01 2024
Journal Name
Journal Of Physics: Conference Series
An investigation into the implications of partial substitution of selenium with lead on the thermal properties for S<sub>60</sub>Se<sub>40-X</sub>Pb<sub>X</sub> Chalcogenide Compound
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Abstract<p>This study includes the manufacture of four ternary alloys represented S<sub>60</sub>Se<sub>40-X</sub>Pb<sub>X</sub> with weight ratios x = 0, 10, 20, and 30 by the melting point method. The components of each alloy were mixed separately, then placed in quartz ampoules and vacuumed out with a vacuum of roger that 10<sup>−4</sup> Torr. The ampule was heated in two stages to avoid sudden dissipation and precipitation of selenium on the inner mass of the quartz tube. The ampoule was gradually heated and kept at 450°C for approximately 4 hours followed by 950°C for 10 hours.at a rate of 10 degrees Celsius, the temperature of the electric furnace</p> ... Show More
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Scopus Crossref
Publication Date
Thu May 01 2014
Journal Name
Engineering And Technology Journal
Relativistic Self-Focusing of Intense Laser Beam in Magnetized Plasma
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Crossref (1)
Crossref
Publication Date
Fri Jun 18 2004
Journal Name
Iraqi Journal Of Laser
Laser Induced Fluorescence of 1,3 Benzodioxole in a Supersonic Jet
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Fluorescence excitation by Nd:YAG pumped dye laser and single vibrational level fluorescence
spectra of 1,3 benzodioxole in a supersonic jet have been obtained and interpreted. The previous assignment of
the 0 0
0 band was incorrect. In addition, many other bands involving n20 and n19 vibrations of a2 symmetry were
confirmed. As far as a1 totally symmetric vibration is concerned. The n14 was assigned to be located in the fivemembered
ring whereas n13 seem to be located in the benzene ring as a result of the electronic transition in the
benzene ring which affects n13 and not n14 wavenumber.

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Publication Date
Fri Jul 21 2023
Journal Name
Journal Of Engineering
Laboratory Investigation on Roller Compaction Technique in Concrete Construction
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Roller compacted concrete (RCC) is a concrete compacted by roller compaction. The concrete mixture in its unhardened state must support a roller while being compacted. The aim of this research work was to investigate the behavior and properties of roller compacted concrete when constructed in the laboratory using roller compactor manufactured in local market to simulate the field conditions. The roller compaction was conducts in three stages; each stage has different loading and number of passes of the roller. For the first stage, a load of (24) kg and (5) passes in each direction had been employed. For the second stage, a load of (104) kg and (10) passes in each direction were conducted. Finally, at the third stage, a load of (183) kg a

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Crossref (2)
Crossref
Publication Date
Mon Dec 03 2018
Journal Name
Journal Of Engineering
Error Investigation for Free Form Surfaces in Bezier Techniques
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Surface modeling utilizing Bezier technique is one of the more important tool in computer aided geometric design (CAD). The aim of this work is to design and implement multi-patches Bezier free-form surface. The technique has an effective contribution in technology domains and in ships, aircrafts, and cars industry, moreover for its wide utilization in making the molds. This work is includes the synthesis of these patches in a method that is allow the participation of these control point for the merge of the patches, and the confluence of patches at similar degree sides due to degree variation per patch.  The model has been implemented to represent the surface. The interior data of the desired surfaces designed by M

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Crossref
Publication Date
Mon Jun 30 2003
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Factors Affecting the Extraction Process
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