Gaz atomizasyonu ile metal tozu üretiminde toz boyutunun sayısal çözümleme ile belirlenmesi

Gas atomization process is based on the disintegration of molten metal to produce metal powders. The disintegration phenomenon is a very complex one to fully understand, and currently, there are no satisfying CFD (Computational Fluid Dynamics) solutions to verify some proposed models. However, that phenomenon has a great impact on the final product and it identifies the characteristics of metal powders. There are a few studies which used different approaches to estimate the particle size and distribution of gas atomization by using CFD solutions with one of the preexisting two-phase models. In this study, interaction of the liquid metal and atomizing gas has investigated via Volume of Fluids (VOF) method of ANSYS/Fluent. This method with a new approach has used to determine the particle sizes and to reveal the atomizing mechanism and characteristics of the gas atomization process

Few layer graphene synthesis via SiC decomposition at low temperature and low vacuum

Based on the large-scale availability and good electrical properties, the epitaxial graphene (EG) on SiC exhibits a big potential for future electronic devices. However, it is still necessary to work continuously on lowering the formation temperature and vacuum values of EG while improving the quality and increasing the lateral size to fabricate high-performance electronic devices at reduced processing costs. In this study, we investigated the effect of the presence of Mo plate and hydrogen atmosphere as well as the vacuum annealing durations on SiC decomposition. Our studies showed that the graphene layers can be produced at lower annealing temperatures (1200 degrees C) and vacuum values (10(-4) Torr) in the presence of Mo plate and hydrogen. For high quality continuous graphene formation, Mo plate should be in contact with SiC. If there is a gap between Mo and SiC, non-wetting oxide droplets on few layer graphene (FLG) are recorded. Moreover, it is found that the morphology of these islands can be controlled by changing the annealing time and atmosphere conditions, and applying external disturbances such as vibration