Although Friction Stir Welding (FSW) is broadly invested in joining aluminum alloys, welding T-joint configurations display revealing challenges due to the interface’s intricate material flow and stress development. Defect formation, including voids and lack of fusion, as well as sudden response forces and residual stresses, can substantially undermine joint performance. This study presents an innovative three-dimensional finite element model to predict the coupled thermomechanical conditions experienced during the friction stir welding (FSW) of AA 6061-T6 lap T-joint design. The study identifies the geometrical parameters of the FSW tool, including shoulder and pin diameters, as well as pin form (cylindrical and tapered), as critical variables affecting thermal and mechanical outcomes. Three distinct tool geometries (T1, T2, T3) were evaluated to achieve the objectives of the current mission of FSW of the AA6061 lap T-joint. This work employs the Coupled Eulerian–Lagrangian (CEL) finite element modality to anticipate and analyze factors influencing the service life of the friction stir welded T-joint. Temperature, plastic strain, von Mises stress, defect type, and force feedback on the tool generated over the fabrication of the T-joint structure were recorded and studied. Alongside thermocouples, infrared cameras were employed to assess the temperature history to validate numerical results, and macrostructural micrographs were produced to identify the type of voids. The findings indicated that the CEL finite element model overestimates the temperature by a maximum of 7% for the T3 tool shape. The plastic strain was more pronounced on the advancing side than on the retreating side. The von Mises stress exhibited an M-shaped distribution, reaching a maximum value of 70 MPa for the T2 tool. The CEL model demonstrated notable ability in capturing the sort of void produced by three distinct tools.
Laboratory studies were conducted at the biological control unit, college of Agriculture, University of Baghdad to evaluate some biological aspects of the predator Chilocorus bipustulatus (Coleoptera: Coccinellidae), which is considered one of the most important predators on many insect pests, especially the scale insect, Parlatoria blanchardi, (Homoptera: Diaspididae) on date palms. The results showed that biological parameters of the predator were varied according to different degree of temperature. Egg incubation period was significantly different and reached to 7.5 and 5.44 day at 25 and 30°C respectively, Fertility was the same 100% at both temperature degrees. Larval growth periods were 17.41 and 16.12 day as well as the mortality
... Show MoreFree radicals are small extremely reactive species that have unpaired electrons. Free radicals include subgroups of reactive species, which are all a product of regular cellular metabolism. Oxidative stress happens when the free radicals production exceeds the capacity of the antioxidant system in the body’s cells.
The current review clarifies the prospective role of antioxidants in the inhibition and healing of diseases.
Information on oxidative stress, free radicals, reactive oxidant species, and natural and synthetic antioxidants was obta
The research aims to identify the effect of the training program that is based on integrating futuristic thinking skills with classroom interaction patterns on mathematics teachers in order to provide their students with creative solution skills. The research sample consisted of 31teachers (15 teachers for the experimental group and 16 for the control groups). The researcher developed a measure for the academic self-efficacy consisting of (39) items. Its validity, reliability, coefficient of difficulty and discriminatory power were estimated. To analyze the findings, the researcher adopted the Mann-Whitney (U) test and the effect size, and the findings were as follows: There is a statistically significant difference at the significance leve
... Show MoreSelf-criticism is that a person confronts himself with his mistakes in order to reform and develop them for the better, motivate them and inspire hope in them to push them forward and continue to give in this life. The Holy Qur’an teaches us, through the models it cited in its verses, that this is through repentance, a feeling of remorse, and a determination to leave mistakes, and quit disobedience and sins, etc., and all this is done through constructive criticism, and at the same time, one must realize his strengths. , in order to succeed in preserving it and employing it in the right path that pleases God, His Messenger, himself and his society. This has been explained through an introduction, two topics and a conclusion, and God is t
... Show MoreSolid state blue laser source is a solid state laser include generation of IR laser light 1064 nm and companied with other wavelength 810 nm that invented from other active medium (Tm:ZBLAN) and non-linear crystal (CLBO) are used to generate fourth harmonic of the resultant wavelength 1874 nm that is blue laser light of 460nm. Several optical component have been designed by multilayer dielectric structure and anti reflection coating analysis. By using MATLAB soft ware, the simulation done and used the following non linear material (ZrO2, HfO2, MgO, SiO, Ta2O5 CaF2) and other linear material (ZnO, MgF2, GaAs, AlAs, BaF2, LiF, TiO2) as coating material. The result showed that as more quarter wave layers are added to the structure, the refl
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One and two-dimensional hydraulic models simulations are important to specify the hydraulic characteristics of unsteady flow in Al-Gharraf River in order to define the locations that facing problems and suggesting the necessary treatments. The reach in the present study is 58200m long and lies between Kut and Hai Cities. Both numerical models were simulated using HEC-RAS software, 5.0.4, with flow rates ranging from 100 to 350 m3/s. Multi-scenarios of gates openings of Hai Regulator were applied. While the openings of Al-Gharraf Head Regulator were ranged between 60cm to fully opened. The suitable manning roughness for the unsteady state was
... Show MoreIncremental Sheet Metal Forming (ISMF) is a modern sheet metal forming technology which offers the possibility of manufacturing 3D complex parts of thin sheet metals using the CNC milling machine. The surface quality is a very important aspect in any manufacturing process. Therefore, this study focuses on the resultant residual stresses by forming parameters, namely; (tool shape, step over, feed rate, and slope angle) using Taguchi method for the products formed by single point incremental forming process (SPIF). For evaluating the surface quality, practical experiments to produce pyramid like shape have been implemented on aluminum sheets (AA1050) for thickness (0.9) mm. Three types of tool shape used in this work, the spherical tool ga
... Show MoreThe subject of this study is one of the most interactive media networks, which is the Instagram.The study uses a descriptive approach and focuses on how Instagram turns from a media tool to a marketing tool. The study problematic consists of this question: How Instagram turns to a marketing tool, and what are the advantages and the disadvantages for that?This study highlights the definition of Instagram, the creation of it and its improvement, the Instagram in Bahrain, the Instagram uses, the Instagram as a marketing tool, and the advantages and disadvantages of using Instagram for marketing.The study confirms that Instagram is a new media network, and focuses on how it develops on later stages and mentions the increase of the percentage
... Show MoreBackground: Periodontal diseases (PD) are common chronic inflammatory diseases caused by pathogenic microorganisms colonizing the gingival area and inducing local and systemic elevations of pro-inflammatory cytokines resulting in tissue destruction by a destructive inflammatory process. Stress was considered as one of the important risk factors that cause many inflammatory diseases including PD. The purpose of this study wasto determines and compares clinical periodontal parameters (PLI, GI and BOP), stress level and salivary IL-1? level among dental students before, during and after mid-year exam, also to find the correlation among stress, IL-1? and clinical periodontal parameters. Materials and methods: The sample was consisted of 24 dent
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