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In industrial applications, welding of dissimilar metals such as aluminum (Al) and titanium (Ti) is a prerequisite for the development of hybrid components with improved mechanical and corrosion properties. However, dissimilar welding of the Al/Ti system is highly challenging due to differences in the physical and thermal properties of the two materials. In the present investigation, an attempt has been made to fabricate a dissimilar friction stir weld (FSW) of commercially pure Al and Ti and to elucidate the mechanism associated with superior joint formation. The process parameters, such as tool rotation speed, traverse speed and tool offset position have been optimized using Taguchi's optimization technique. A detailed investigation of the weld with optimum process parameters has been carried out to reveal the mechanism of joint formation. The superior mechanical properties (24% higher ultimate tensile strength and 10% higher ductility than that of base Al) of the weld are attributed to the fabrication of a defect-free joint, formation of intercalated particles and an Al/Ti interlocking interface, homogeneous distribution of fine second-phase (Ti and/or intermetallics) particles in the weld nugget, reduction in the evolution of brittle Al3Ti intermetallic compounds (IMCs) and recrystallization and grain refinement of Al in the weld nugget. The potentio-dynamic polarization test indicated that the optimized Al/Ti weld has ~47% higher corrosion resistance than Al; it had a very mild corrosion attack due to the homogeneous dispersion of fine particles. The method and mechanism could have an immense influence on any dissimilar weld and metal matrix composites, improving their mechanical properties and corrosion resistance. [ABSTRACT FROM AUTHOR]

With the introduction of stricter energy-efficiency-ratio regulations, the surface-mounted permanent-magnet motor (SPM) is gaining increasing attention due to its inherent high-power density. This article investigates the feasible SPM structures for refrigerant compressor applications, particularly those used in metal industry factories with high surrounding temperatures so that cost-effective solutions can be achieved. A theoretical model is first established to aid structural parameter optimizations and the management of specific operational objectives and constraints; multiple SPM arrangements are investigates, with ease of manufacturing implementation being one consideration, as shown in Liu et al., 2021. Detailed finite element calculations and experimental measurements are performed to develop feasible SPMs with optimized structural arrangements that meet the desired operational objectives. [ABSTRACT FROM AUTHOR]

Present investigation deals with pin-on-disk type of tribometer used to conduct abrasive wear testing of in situ Al–4.5%Cu–xTiB2 composites for enhanced understanding of the physical wear phenomenon. Characterization studies for comprehending ceramic TiB2 reinforcement distribution and wear surface topology analysis of Al–4.5%Cu–xTiB2 composites were executed through field emission scanning electron microscopy, X-ray diffraction, and high-resolution atomic force microscopy techniques. Experimental design based on full factorial method and Taguchi's orthogonal array has been employed in the study to conduct wear experimental runs and study control parameters that are affecting the wearing phenomenon. Taguchi's loss function method along with the assistance of MINITAB 17 software was used to optimize various control parameters involved in the experiment. ANOVA method was employed further to identify percentage contribution of various control parameter combinations affecting the output parameters. Furthermore, regression model was developed to assist in calculation of output response parameters based upon the existing wear experimental results. Consequently, this in-depth investigation on wear characteristics can immensely help in understanding the true influence of various parameters and their effects on the wear phenomenon of Al–4.5%Cu–xTiB2 composites. [ABSTRACT FROM AUTHOR]

A near-optimal base-station antenna array synthesis suitable for broadcasting applications is presented. The array is required to provide a high-gain radiation pattern with a main lobe slightly tilted from the horizontal plane and null filling inside an angular sector under the main lobe. To satisfy the above requirements, a novel invasive weed optimization (IWO) variant called Taguchi initialized IWO (TI-IWO) is proposed in this paper. In TI-IWO, the Taguchi's optimization method is employed to initialize effectively the positions of the weeds used by the IWO method. In this way, the fitness function starts from lower values and, thus, the TI-IWO method finds better near-optimal solutions than the conventional IWO method. The proposed method has been applied to linear arrays. Due to its easy implementation in practice, a uniform-amplitude excitation distribution is considered to be applied on the array elements. Two cases of isotropic source arrays are studied under specific requirements for maximum possible gain, main lobe tilting, and null filling. Also, the TI-IWO method is applied to optimize realistic cases of collinear wire dipole arrays in front of a mast under the same requirements and an additional one concerning the impedance matching of all the dipoles. [ABSTRACT FROM AUTHOR]