Papers by Keyword: SEM/EDS

Abstract: Sidoarjo mudflow (SM) is a new cementitious material originating from a natural disaster of volcano mudflow in Porong, Sidoarjo, East Java, Indonesia. Some investigations mentioned that the material of SM is rich in Si, Fe, Al and Ca content. The content of Si and Al were considered to be able to generate the gel of Si-O-Si and Si-O-Al in the geopolymer binder. However, the feasibility of SM material as an alternative binder in geopolymer still needs to be investigated in this study. The production of SM material was calcined at the temperature of 400°C up to 900°C which the optimum calcination temperature was about 700°C. This material was called as volcano meta ash (VMA). The analysis of XRD showed that the geopolymer binder of VMA, FA_VMA, and FA had the crystalline in quartz, mullite, magnetite, hematite, and rutile. The analysis of FTIR described that the geopolymer binder of VMA and FA_VMA had similar stretching in the gel of Si-O-Si and Si-O-Al to the geopolymer binder of FA. However, the stretching and bending of H-O-H in the geopolymer binder of VMA and FA_VMA were less than the geopolymer binder of FA. Finally, the analysis of SEM showed that the geopolymer binder of VMA has less concavity and more gel compared to the geopolymer of FA_VMA and FA.

Abstract: Riceberry brown rice is regarded as a source of various nutrients; often richer than white rice. Non-thermal plasma has recently been gaining a role for improving properties of cereal grains, especially brown rice. A number of methods of plasma treatment has been proposed including discharges as capacitive coupled plasma (CCP) and inductive coupled plasma (ICP). ICP has two operation modes as capacitive (E-mode) and inductive (H-mode) discharge with rather distinct characters. In this study we have focused on using ICP Ar/O₂ plasma in both E-and H mode for plasma treatment on riceberry brown rice. The input power for plasma generation were set to 50 and 250 W for E-and H-mode, respectively. Plasma in H-mode was having higher plasma density than that in E-mode, as observed in the optical emission spectrum. The surface morphology of riceberry brown rice before and after Ar/O₂ plasma treatment was evaluated using a scanning electron microscope without or with an energy dispersive spectroscopy (SEM and SEM/EDS). It has been found that the bran layer was richer in elemental compositions than the endosperm. The surface of rice sample was found to be etched and more porous after plasma treatment. The Ar/O₂ plasma in H-mode was observed to offer higher effect. The surface contact angle was found to decrease from 120.1^o ± 0.9^o in untreated samples to 79.3^o ± 0.6^o and 99.2^o ± 0.8^o in plasma treated samples on E-and H-mode, respectively.

Abstract: In present study HVOF spraying process had been employed for depositing 93(WC-Cr₃C₂)-7Ni, 75Cr₃C₂-25NiCr, 83WC-17CO and 86WC-10CO-4Cr coatings on ASME SA213 T22. All the coatings were found dense and uniform having thickness between 200-250µm. All the coatings on ASME SA213 T22 used in present studies have provided resistance to corrosion in coal fired boiler environment in superheater zone when exposed for 10 cycles at 900°C. Each cycle consists of 100 hours heating followed by 1 hour cooling at ambient conditions. X-ray diffraction (XRD), Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS) techniques were used to analyse corrosion products. The results showed that among coated specimens 93(WC-Cr₃C₂)-7Ni and 75Cr₃C₂-25NiCr coatings has shown maximum and minimum resistance to corrosion respectively. The better corrosion resistance of 93(WC-Cr3C2)-7Ni coated steel alloys may be attributed to the formation of thin band of oxides of nickel, chromium; and carbides of tungsten.