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Magnesium AZ91/AlN-based surface composites have been synthesized using the friction stir processing (FSP) technique. The influence of particle addition during FSP on microstructural and mechanical properties has been investigated. Composite plates of 5, 10, and 15 vol. % AlN were synthesized using two-pass FSP with an axial force of 10 KN, a tool travel speed of 40 mm/min, and a tool rotation speed of 1200 rpm. The AZ91/AlN surface composites were analyzed microscopically with the use of an optical microscope, an x-ray diffractometer, and a scanning electron microscope. The prepared composites were tested for hardness and tensile strength. Micrographs taken in the stir zone revealed a consistent distribution of AlN particles throughout the AZ91 matrix. The AZ91/AlN surface composites were tested for hardness and tensile strength, and the findings showed that the AlN particles improved the mechanical properties without significantly decreasing ductility. The fracture surfaces of the composites were studied, and the mechanisms of fracture were identified. [ABSTRACT FROM AUTHOR]

In the present digital era, the exploitation of medical technologies and massive generation of medical data using different imaging modalities, adequate storage, management, and transmission of biomedical images necessitate image compression techniques. Vector quantization (VQ) is an effective image compression approach, and the widely employed VQ technique is Linde–Buzo–Gray (LBG), which generates local optimum codebooks for image compression. The codebook construction is treated as an optimization issue solved with utilization of metaheuristic optimization techniques. In this view, this paper designs an effective biomedical image compression technique in the cloud computing (CC) environment using Harris Hawks Optimization (HHO)-based LBG techniques. The HHO-LBG algorithm achieves a smooth transition among exploration as well as exploitation. To investigate the better performance of the HHO-LBG technique, an extensive set of simulations was carried out on benchmark biomedical images. The proposed HHO-LBG technique has accomplished promising results in terms of compression performance and reconstructed image quality. [ABSTRACT FROM AUTHOR]

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A356 Aluminium Alloy-Zircon composites were synthesized through the stir casting technique by introducing different volume fractions of zircon particles (3, 6, and 9 %). Stir casting process was carried out at the stirring speed of 600 rpm and stirring time of 10 minutes. The microstructure of the composites showed an even distribution of zircon particles. The composites' hardness improved with an increase in vol.% of zircon constituent part. Wear loss against different sliding distances and load was investigated through a Pinon-Disc wear testing apparatus with an L16 orthogonal array. Taguchi's parameter optimization demonstrated that material loss was influenced to a significant extent by adding Zircon. Wear resistance of the synthesized composite was investigated and verified using Analysis of Variance (ANOVA). Zircon content (39.33%) was found to be the most influencing factor on wear loss, followed by the applied load (36.80%) and sliding distance (21.54%). Zircon improves the properties of the composite through restricting the growth of dendritic arms in A356 alloy. In addition, reinforcement particles enhanced the strengthening of the composites through Orowan mechanism by inhibiting the movement of dislocations. ANOVA technique was successfully used to examine the effect of individual parameters on wear loss of A356 alloy-Zircon composites MMCs. [ABSTRACT FROM AUTHOR]

The present study aims to investigate the microstructure and mechanical properties of the A356 aluminum metal matrix composite reinforced with Y2O3 particles. The composite is synthesized by adding 1 and 2 vol.% of reinforcement via stir casting assisted by ultrasonic treatment (UT). Microstructural contemplates show improvement in the dispersion of nano Y2O3 particles and a decrease in the porosity level due to the ultrasound aided synthesis. The UT refines the size of the Y2O3 particles as well as helps to improve their dispersion. The secondary dendrite arm spacing of 2 vol.% Y2O3 reinforced samples with 5 min UT are found to be significantly reduced to 12 μm as compared to that of the as-cast A356 alloy. The addition of 2 vol.% of nanoY2O3 has significantly improved the hardness of the A356 alloy from 60 HV to 108 HV. A considerable increment in the YS and TS of the A356 alloy is observed with the increase in the amount of Y2O3 and found to further improve with UT. However, minimal reduction in ductility is observed with the addition of Y2O3 as well as ultrasonic treatment. [ABSTRACT FROM AUTHOR]