Effect of microwave crystallization on the wear resistance of reinforced glass-ceramics

This study compared the wear resistance of different reinforced glass-ceramics crystalized by conventional or microwave firing. The wear rate of three ceramics [one lithium disilicate ceramic (LD): IPS e.max CAD – Ivoclar Vivadent; and two zirconia reinforced lithium silicates: Suprinity – VITA Zahnfabrik (ZLS1) and Celtra Duo – Dentsply (ZLS2)] crystallized by conventional (c) or microwave (mw) firing protocols were collected according to the contact- [two-body (n = 20/gr)] and contact-free wear tests [three-body (n = 20/gr)]. After wear tests performed on ACTA wear machine, mean surface roughness (Ra) and Scanning Electron Microscopy (SEM) analyzes were performed to evaluate the surface alterations. The wear and roughness data (in μm) were evaluated using two-way ANOVA and Tukey post-hoc test (α = 0.05). Two-body wear test revealed that ZLS1 (1.30 ± 1.79)A showed higher wear rate than LD (0.79 ± 2.15)B and ZLS2 (0.85 ± 0.94)B, regardless the crystallization approach. For three-body test, conventional crystallization (0.62 ± 0.4)A showed higher wear rates than microwave (0.22 ± 0.71)B; while the type of ceramic was not significant. The crystallization protocol (p < 0.001) and ceramic material (p = 0.001) affected the surface roughness in the three-body; whereas the two-body test, only the crystallization protocol (p = 0.046). SEM analysis showed a similar and smother surface morphology for LD and ZLS2 compared to ZLS1. Conventional crystallization showed materials more prone to wear than the microwave, in the presence of food bolus. Therefore, the microwave crystallization can be suggested as an alternative to improve the evaluated glass-ceramics wear resistance

ADVANCES IN THE PROPAGATION OF RAMBUTAN TREE

ABSTRACT The reality of Brazilian fruit farming is demonstrating increasing demand for sustainable information about native and exotic fruit, which can diversify and elevate the efficiency of fruit exploitation. Research on propagation of fruits tree is very important so that it can provide a protocol for suitable multiplication of this fruitful. Due to the great genetic diversity of rambutan plants, it is recommended the use of vegetative propagated plants. This research aimed to evaluate the propagation of rambutan by cuttings, layering and grafting, as well as seed germination and viability without storage. The results of this research indicate that this species can be successfully propagated by layering, grafting and seeds. We also observed that the germination percentage of seeds kept inside the fruits for six days were not influenced by the different substrates used in this experiment

Strategies for mitigation of nitrogen environmental impact from swine production Estratégias para minimização do impacto ambiental do azoto em suinicultura

This work presents strategies that can be implemented in order to minimize the environmental impact of swine slurry on soil, water, and air. This reduction can be achieved through decrease in nitrogen excretion and ammonia emissions. The correct feed formulation according to animal requirements, the increase in diet digestibility and improvement in animal performance can reduce nitrogen excretion. The use of additives either in the diet or in the manure as well as some equipment rearrangements can reduce ammonia emission.<br>Neste trabalho são apresentadas estratégias que podem ser implementadas para minimizar o impacto ambiental dos efluentes da produção suína sobre o solo, a água e a atmosfera. Esta redução pode ser obtida com a excreção de azoto e a sua volatilização. A formulação mais ajustada às necessidades dos animais, o aumento da digestibilidade da dieta e a melhoria do desempenho dos animais podem reduzir a excreção de azoto. O uso de aditivos nas dietas ou nos dejectos e alterações nas instalações pode reduzir a volatilização da amónia