ABSTRACT
To obtain appropriate crucible materials for vacuum induction melting of MCrAlY alloys, four different oxide ceramics, including MgO, Y2O3, Al2O3, and ZrO2, with various microstructures were designed and characterized. The high-temperature wettability and interactions between Ni-20Co-20Cr-10Al-1.5Y alloys and oxide ceramics were studied by sessile drop experiments under vacuum. The results showed that all the systems exhibited non-wetting behavior. The contact angles were stable during the melting process of alloys and the equilibrium contact angles were 140° (MgO), 148° (Y2O3), 154° (Al2O3), and 157° (ZrO2), respectively. The interfacial reaction between the ceramic substrates and alloys occurred at high temperature. Though the ceramics had different microstructures, similar continuous Y2O3 reaction layer with thicknesses of about 25 μm at the alloy-ceramic interface in MgO, Al2O3, and ZrO2 systems formed. The average area percentage of oxides in the alloy matrices were 0.59% (MgO), 0.11% (Al2O3), 0.09% (ZrO2), and 0.02% (Y2O3), respectively. The alloys, after reacting with MgO ceramic, had the highest inclusion content, while those with the lowest content were in the Y2O3 system. Y2O3 ceramic was the most beneficial for vacuum induction melting of high-purity Y-containing Ni-based alloys.
ABSTRACT
OBJECTIVE: To understand the cost-effectiveness of schistosomiasis monitoring in Rugao City, a schistosomiasis transmission interrupted area, so as to provide the evidence for improving schistosomiasis control. METHODS: According to the national and Jiangsu provincial working scheme of schistosomiasis monitoring and consolidation, the data of schistosomiasis monitoring were collected and the cost-effectiveness was analyzed in Rugao City from 2001 to 2010. RESULTS: During 10 years, the financial input for Oncomelania snail survey was 11.694 8 million Yuan, accounting for 92.9% of the total monitoring cost. In 6 years, a few remaining snails with low density and small area were detected, and per 100 m2 snail area spent 76 788 Yuan averagely. Totally 23 694 people were investigated with serological tests and 15 persons were positive, but no person was positive in feces tests, and the accumulative total cost was 410 350 Yuan. The average cost for detection of 1 person was 17.32 Yuan. Totally 454 heads of cattle were investigated but there was no positive, and the accumulative total cost was 18 716 Yuan and the average cost of detection of 1 case was 41.22 Yuan. The health education during the 10 years spent 172 500 Yuan, only accounting for 1.4% of the total monitoring funds. The awareness rate of schistosomiasis control knowledge and the health behavior formation rate increased year by year, and they were increased by 2.48 times and 2.71 times respectively from 2001 to 2010. CONCLUSIONS: In schistosomiasis transmission interrupted areas and areas with Oncomelania snails but without schistosomiasis, the monitoring index and monitoring method need to be studied and adjusted. Health education has a good cost-effectiveness.
