23 research outputs found
Double-Lepton Polarization Asymmetries and Branching Ratio in B \rar K_{0}^{*}(1430) l^+ l^- transition from Universal Extra Dimension Model
We investigate the B \rar K_{0}^{*}(1430) l^+ l^- transition in the
Applequist-Cheng-Dobrescu model in the presence of a universal extra dimension.
In particular, we calculate double lepton polarization asymmetries and
branching ratio related to this channel and compare the obtained results with
the predictions of the standard model. Our analysis of the considered
observables in terms of radius of the compactified extra-dimension as the
new parameter of the model show a considerable discrepancy between the
predictions of two models in low values.Comment: 12 Pages, 15 Figures and 1 Tabl
Predicting the tensile strength, impact toughness, and hardness of friction stir-welded AA6061-T6 using response surface methodology
In this research, an attempt has been made to develop mathematical models for predicting mechanical properties including ultimate tensile strength, impact toughness, and hardness of the friction stir-welded AA6061-T6 joints at 95 % confidence level. Response surface methodology with central composite design having four parameters and five levels has been used. The four parameters considered were tool pin profile, rotational speed, welding speed, and tool tilt angle. Three confirmation tests were performed to validate the empirical relations. In addition, the influence of the process parameters on ultimate tensile strength, impact toughness, and hardness were investigated. The results indicated that tool pin profile is the most significant parameter in terms of mechanical properties; tool with simple cylindrical pin profile produced weld with high ultimate tensile strength, impact toughness, and hardness. In addition to tool pin profile, rotational speed was more significant compared to welding speed for ultimate tensile strength and impact toughness, whereas welding speed showed dominancy over rotational speed in case of hardness. Optimum conditions of process parameters have been found at which tensile strength of 92 %, impact toughness of 87 %, and hardness of 95 % was achieved in comparison to the base metal. This research will contribute to expand the scientific foundation of friction stir welding of aluminum alloys with emphasis on AA6061-T6. The results will aid the practitioners to develop a clear understanding of the influence of process parameters on mechanical properties and will allow the selection of best combinations of parameters to achieve desired mechanical properties