Laser modification techniques have been widely adopted in the field of surface engineering. Among these modified techniques, ultra-high-speed laser cladding is trending most nowadays to fabricate wear-resistant surfaces. The main purpose of this research is to provide a detailed insight of ultra-high-speed laser cladding of hard Ni60 alloy on LA43M magnesium alloy to enhance its surface mechanical properties. Multiple processing parameters were investigated to obtain the optimal result. The synthesized coating was studied microstructurally by field emission scanning electron microscopy (FESEM) equipped with an energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The microhardness and wear resistance of the Ni60 coating were analyzed under Vickers hardness and pin on disc tribometer respectively. The obtained results show that the dense Ni60 coating was fabricated with a thickness of 300 μm. No cracks and porosities were detected in cross-sectional morphology. The Ni60 coating was mainly composed of γ-Ni and hard phases (chromium carbides and borides). The average microhardness of coating was recorded as 948 HV0.3, which is approximately eight times higher than that of the substrate. Meanwhile, the Ni60 coating exhibited better wear resistance than the substrate, which was validated upon the wear loss and wear mechanism. The wear loss recorded for the substrate was 6.5 times higher than that of the coating. The main wear mechanism in the Ni60 coating was adhesive while the substrate showed abrasive characteristics.
Measles is one of the most prevalent and serious infectious disease among children in the third world countries contributing to a high degree of morbidity and mortality unless they are either protected by high maternal antibody titer or by vaccination. Some work is still required regarding the optimum age of measles vaccination in developing countries. The present study was undertaken to find out the age where maternal antibodies declined and indicate the appropriate age for vaccination. A total of 606 blood samples were collected. 449 including 39 cord samples were collected from unvaccinated children between 0-36 months. 157 samples were analyzed for antibody response to live attenuated measles virus vaccine in 10-36 months. Haemagglutination Inhibition test (HI) was used to obtain stable titers. The percentage of maternal antibodies varied in each group. The highest antibodies 100% were observed in cord blood and 0-1 months of age group while lowest 17.39% in nine months. A large increase in active immune response after vaccination was observed. The geometric mean titer (GMT) being significantly different before and after vaccination. At 13-24 months GMT was 5.038% before and 77.25% after vaccination. At 25-36 months GMT was 5.038% before and 87.2% after vaccination. It is concluded from this study that optimal age of measles vaccination in children is nine months.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.