On investigating the soda-lime shot blasting of AZ31 alloy:Effects on surface roughness,material removal rate,corrosion resistance,and bioactivity

In the present study,a novel method of surface finish improvement is proposed using shot blasting of soda lime(SBSL)beads on the Mg-AZ31 alloy.The effect of the soda blasting process parameters,such as blast pressure,stand-off distance,and blast duration,have been studied in-response of material removal rate(MRR)and surface roughness(SR)and corresponding statistical models have been obtained.The multi-objective optimization has also been performed to obtain parameters for maximum MRR and minimum SR.The corrosion behavior of the treated specimens has been performed to study their in-vitro biodegradability in simulated body fluid(SBF)for 1,3,7,10,15,and 21 days.The wettability study of the SBSL treated samples has been investigated using sessile drop methodology.Further,cell adhesion test has also been performed to study the biocompatibility characteristics of the SBSL treated samples using Huh7 liver cell lines.Based on obtained quantitative data as well as scanning electron microscopy analysis of treated samples,the SBSL treatment of the AZ31 alloy has been found highly useful in producing biocompatibility surfaces along with desirable morphological features.

Numerical analysis of hemodynamic parameters in stenosed arteries under pulsatile flow conditions

This research studies the changes in flow patterns and hemodynamic parameters of diverse shapes and sizes of stenosis.Six different shapes and sizes of stenosis are constructed to investigate the variations in hemodynamics as the morphology changes.Changes in shape(trapezoidal and bell-shaped)and sizes of stenosis change the stresses on the walls and their flow patterns.TAWSS and OSI results specify that trapezoidal stenosis exerts greater stress than bell-shaped stenosis.Also,as the length of the trapezoidal stenosis increases,the TAWSS increases,whereas the trend is the opposite for bell-shaped stenosis.Later,this paper also studies different degrees of stenosis extracted from real images.Changes in velocity flow patterns,wall shear stress(WSS),Time-averaged wall shear stress(TAWSS)and Oscillatory shear index(OSI)have been studied for these images.Results illustrate that the peak velocity rises drastically as the stenosis percentage increases.Negative velocity is seen close to the artery's walls,indicating flow separation.This flow separation region is seen throughout the cycle except in the accelerating flow region.An increase in stenosis also increases WSS and TAWSS drastically.Negative WSS is seen downstream of stenosis,indicating flow recirculation.Such negative WSS in the blood vessels also promotes endothelial dysfunction.OSI values greater than 0.2 are seen near the stenosis region,indicating atherosclerosis growth.Regions of high OSI and low TAWSS are also identified,indicating probable regions of plaque development.

Plasma Spray Deposition of HA-TiO2 on β-phase Ti-35Nb-7Ta-5Zr Alloy for Hip Stem: Characterization of Bio-mechanical Properties, Wettability, and Wear Resistance

In this work,a biomimetic coating of hydroxyapatite(HA)-and titania(TiO2)was deposited on low elastic β-phase Ti-35Nb-7Ta-5Zr(β-TNTZ)alloy by plasma spray deposition technique for orthopedic applications.The effect of TiO2 reinforcement on microstructure,mechanical properties,and bioactivity was investigated.The morphology,coating thickness,elemental composition,and phase composition of the developed coatings were characterized.The biomechanical behavior of the deposited coatings was investigated in terms of surface hardness,elastic modulus,and adhesion strength.It was found from the morphological investigation that the TiO2 reinforcement improves the microstructure and prevents the formation of defects in the coating.The biomimetic HA-TiO2 coated surface possessed pores,size ranging from 200 nm-600 nm that benefits the apatite growth and osseointegration.The EDS spectrum,mapping,and XRD analysis show that the deposited layerβ-TCP,CaO,TTCP,TiO2 phases.The HA-TiO2 coating exhibits a very dense and thick layer of 100μm-125am that exhibits excellent adhesion strength to offer mechanical interlocking to prevent delamination.The alloying of TiO2 improves the hardness from 1.67 GPa to 2.95 GPa that enhances the wear resistance.It was found that HA-TiO2 coating exhibits better hydrophilic and biocompatible surface as compared to HA-coating.