The current study performs an explicit nonlinear finite element simulation to predict temperature distribution and consequent stresses during the friction stir welding (FSW) of AA 7075-T651 alloy. The ABAQUS® finite element software was used to model and analyze the process steps that involve plunging, dwelling, and traverse stages. Techniques such as Arbitrary Lagrangian–Eulerian (ALE) formulation, adaptive meshing, and computational feature of mass scaling were utilized to simulate sequence events during the friction stir welding process. The contact between the welding tool and workpiece was modelled through applying Coulomb’s friction model with a nonlinear friction coefficient value. Also, the model considered the effect of nonlinear material properties as well as heat transfer conditions such as heat losses due to convection and thermal contact conductance between the workpiece and the backing plate interface on the thermal history. To validate the computational model results, an experimental procedure was carried out to measure temperature history on both sides of the specimen as well as the plunging force throughout the whole process time. The results obtained showed that symmetrical temperature distribution throughout the workpiece width was distinguished, implying that the tool rotation has a minor effect on the final temperature distribution. In addition, asymptotic V shape with high gradient temperature value in the weld nugget region after the full plunging was distinguished. Mechanical stresses and related plastic deformations generated, while achieving the FSW samples were evaluated in addition to the tool reaction force and heat generated to protect against tool failure.
The Fauqi field is located about 50Km North-East Amara town in Missan providence in Iraq. Fauqi field has 1,640 MMbbl STOIIP, which lies partly in Iran. Oil is produced from both Mishrif and Asmari zones. Geologically, the Fauqi anticline straddles the Iraqi/Iranian border and is most probably segmented by several faults. There are several reasons leading to drilling horizontal wells rather than vertical wells. The most important parameter is increasing oil recovery, particularly from thin or tight reservoir permeability. The Fauqi oil field is regarded as a giant field with approximately more than 1 billion barrels of proven reserves, but it has recently experienced low production rate problems in many of its existing wells. This study
... Show MoreABSTRACT Background:- White spot lesions are common esthetic problem that compromise the success of orthodontic treatment. This study aimed to assess white spot lesions in patients with fixed orthodontic appliance at different time intervals. Materials & Methods:- Thirty two patients (24 females and 8 males) were included in this study and they underwent clinical examination for white spot lesions using enamel decalcification index at four time intervals: (2-3 weeks after appliance insertion, 2, 4 and 6 months). Results:- The patients were free of white spot lesions at the appliance insertion visit. The mean of white spot lesions was 2.22 which were increased significantly during six months to reach 24.59 at the end of study. There was a si
... Show MoreThe reserve estimation process is continuous during the life of the field due to risk and inaccuracy that are considered an endemic problem thereby must be studied. Furthermore, the truth and properly defined hydrocarbon content can be identified just only at the field depletion. As a result, reserve estimation challenge is a function of time and available data. Reserve estimation can be divided into five types: analogy, volumetric, decline curve analysis, material balance and reservoir simulation, each of them differs from another to the kind of data required. The choice of the suitable and appropriate method relies on reservoir maturity, heterogeneity in the reservoir and data acquisition required. In this research, three types of rese
... Show MoreThe reaction of 1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one with one equivalent of 4-chlorophenol by coupling reaction afforded (E)-4-((5-chloro-2- hydroxyphenyl)diazenyl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one. Then azo ligand was characterize using spectroscopic studies ( FTIR,UV-Vis, 1H and 13CNMR, Mass) also micro-elemental analysiz (C.H.N.O). Transition metal chelation with Co(II), Ni(II), Cu(II), and Zn(II) was investigated, revealing 1:2 metal-to-ligand stoichiometry with octahedral geometry. The biological, and industrial application for the azo ligand and it is complexes were evaluated, demonstrating antimicrobial activity against bacterial and fungal strains, with the Zn(II) complex exhibiting superior inhibition. Additionally,
... Show MoreInnovative various Schiff bases and their Co(II), Ni(II) and Cu(II) and Hg(II) compounds made by the condensation of 4-amino antipyrine with derived aminobenzoic acid (2-aminobenzoic acid, 3-aminobenzoic acid, and 4-aminobenzoic acid ) have been prepared by conventional approaches. These complexes were described by magnetic sensibility analysis, FT-IR spectra, and molar-conductance and elemental analysis. Analytical values appeared which the mixed-ligand complexes presented ratio about 2:1 (ligand: metal) with the chelation 4 or 6. The prepared compounds offered a good effect on the organisms; bacteria Staphylococcus-aurous, Escherichia-coli and fungi C. albicans, A. niger. Also, the biological products signalize which the mixed compl
... Show MoreThis research aims to knowledge of the scope of applying the international specification of which is regarded to occupational health and safety management system (OHSAS 18001) second edition for year 2007 by The AL-Mammon Factory / The General Company For Vegetable Oils Industry in order to diagnosis the gap between specification requirements and reality by using the checklist made based upon the items of the specification, after translating the English copy into Arabic. The results of the research and analysis that occupational health and safety management system in comparison to the specification requirements in all of its main items, which was (%22.26) applied and documented partly, this refer to the existence of great gap (%7
... Show MoreSome auditors may think that the audit process ends with discovering misstatements and informing management about them, while the discovery of misstatements may be classified by some as the first step in the phase of separating these distortions, as the auditor should collect these misstatements, evaluate them and detail them into misstatements involving errors or misstatements involving fraud Then evaluating it to material or immaterial according to what was stated in the international auditing standards and directing management to amend the essential ones. The importance of this research lies in identifying the concept of distortions and their types, identifying the method of evaluating distortions into substantial and non-essent
... Show MoreTo assess the biochemical, mechanical and structural characteristics of retained dentin after applying three novel bromelain‑contained chemomechanical caries removal (CMCR) formulations in comparison to the conventional excavation methods (hand and rotary) and a commercial papain‑contained gel (Brix 3000). Seventy‑two extracted permanent molars with natural occlusal carious lesions (score > 4 following the International Caries Detection and Assessment System (ICDAS‑II)) were randomly allocated into six groups (n = 12) according to the excavation methods: hand excavation, rotary excavation, Brix 3000, bromelain‑contained gel (F1), bromelain‑chloramine‑T (F2), and bromelain chlorhexidine gel (F3). The superficial and deepe
... Show MoreBackground: Bone augmentation techniques are commonly employed in medical fields. This biomaterial system must be readily available, easily applicable by minimally-invasive technique and able to release an osteoinductive growth factor. Such a system will be able to engineer new bone formation locally at the site of injection. Hyaluronic acid has osteogenic potential that can be exploited not only for repairing bone defects but also for providing transplantable bone for the reconstruction of a variety of bone defects. The aims of this study were to evaluate the effects of Hyaluronic acid gel on bone healing by immunohistochemical estimation of transforming growth factor -beta 3 in experimental and control groups. Materials and methods: Thirt
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