Abstract: The upgrade recycling process of cast-iron scrap chips toward β-FeSi2 is regarded as an eco-friendly and cost-effective production process. It is useful for reducing the material cost in fabricating β-FeSi2 by utilizing the waste that is obtained from the manufacturing process of cast-iron components. In this research, β-FeSi2 was successfully obtained from cast iron bscrap chips and showed good thermoelectric performance in Seebeck coefficient and electrical conductivity which is around 70% to almost 100% compared to β-FeSi2 that was prepared from pure Fe and other publications. The thermoelectric power factor was achieved 90% performance compared to other literatures and β-FeSi2 prepared from pure Fe.
Abstract: Two-step sintering with controlled oxygen partial pressure by using metallic buffer was applied to obtain dense non-stoichiometric CeO2-x. The samples prepared with single step sintering were cracked. The two-step sintering promoted almost full densification ≈ 98% in relative density without any cracks. Relative density of CeO2-x reached more than 98% of the theoretical density. The value of x in CeO2-x was obtained in the range of 1.68 in Mn/MnO to 1.98 in Co/CoO.
Abstract: Significant amounts of fluorescent light have been discarded every year. Mercury is released into the atmosphere in the recycling process of it, if improperly treated. The adsorption method is used to remove mercury discharged from the recycling step of fluorescent light.We studied the impregnation condition of adsorbent made from sewage sludge. And also adsorption characteristics of mercury were evaluated by impregnated adsorbent.According to our results, the adsorption efficiency of mercury was increased by impregnating adsorbent with chlorine and iodine. The adsorption capacity was described by Langmuir isotherm model.
Abstract: In this work, pastes were prepared from slag and MSWI bottom ash by geopolymer technique. And its physical property was evaluated with mixing ratio of sodium silicate and potassium silicate. The amounts of leaching products, such as silica, alumina and calcium ions were changed for mixing ratio of raw materials. The compressive strength was increased with the increment of leaching amount of silica, alumina and calcium ions.
Abstract: The FRP(fiber reinforced plastics) spacer was fabricated to enhance the heat blocking and mechanical properties of insulating glass for energy-saving eco-friendly home. The fiber volume percent in ABS(acrylonitrile-butadiene-styrene) matrix was chosen as a main controlling factor. The various properties of FRP spaces were evaluated such as 3-point bending strength, thermal conductivity, and water absorption rate. And the aging test was performed at various temperatures for the spacer immersed in water. In conclusion, the optimum fiber volume percent, 25wt% of spacer was found that is enough for handling in construction process and appropriate for blocking the heat loss through the insulating glass window.
Abstract: Recently the wind power was customized to offshore due to more abundant wind than onshore. Transformer is a multi-terminal electrical device that transforms electrical energy and is filled with insulating oil. This study presents the feasibility of diglycerol ester as insulating oil for offshore wind turbine transformers. The sulfated zirconia (SZ) was prepared by the sol-gel method for use on synthesize of diglycerol ester. The diglycerol ester was synthesized with diglycerol and fatty acids over SZ for use on insulating oil of offshore wind turbine transformer. The SZ600 has the highest conversion of fatty acids. The insulation properties of synthesized diglycerol ester over SZ600 shows that the pour point is-50°C and the flash point is 316°C. Therefore, it is suitable for diglycerol ester over SZ600 to be used in offshore wind turbine transformer.
Abstract: Due to changing of wind power from on-shore to off-shore, it is necessary to eco-friendly features but also insulating characteristics. The purpose of this study is to confirm that effect of deposited material and amount of catalyst for synthesis of TMP(tri-methylol propane)-ester as vegetable insulating oil. Potassium fluoride and potassium bromide were deposited via an impregnation method on HAP(hydroxyapatite). The effects of deposited material loading on the characteristics of the catalysts were investigated through XRD, XRF, FE-SEM, BET and TPD. We confirmed that KF/HAP catalyst has higher activity than KBr/HAP. The higher activity of KF(40%)/HAP catalyst showed the best catalytic properties.
Abstract: Magnesium alloys have recently attracted increased attention as structural materials owing to their low specific gravity. However, they must typically be casted, formed, melted, and even heated under a protective shielding gas to prevent them from oxidizing and igniting. So-called “ECO-Mg” alloys have recently been developed by adding CaO to conventional Mg alloys. ECO-Mg alloys exhibit higher oxidation resistance during melting and superior castability, even when beryllium is not added or toxic protective gasses such as SF6 are not used. We laser-welded AZ31 Mg alloys with various CaO contents and examined the mechanical properties of the welds. Increasing the CaO content in the AZ31 increased the burning resistance of the ECO-Mg alloys, thereby suppressing plume generation during laser welding; thus the ECO-Mg alloy welds could be fully penetrated faster than conventional Mg alloy welds. The weld strength also increased with increasing CaO content in the AZ31 because the CaO refined the grains.
Abstract: In this study, nitrogen doped graphene (NG) was prepared by using hydrothermal treatment of graphene oxide (GO) and ethylene diamine (EDA). The surface chemistry of the reduced graphene oxide (rGO) and the NG was investigated by the X-ray photoelectron spectroscopy (XPS). The results revealed that there were four kinds of nitrogen substitution: pyrollic N, pyridinic N, graphitic N and C-NH2. Further, the electrical measurements illustrated that the NG had superior capacitive performance than that of the rGO. Specifically, the maximum specific capacitance of NG was 200.6 F/g due to the double-layer capacitive and pseudocapacitive effect from the nitrogen-doped graphene. In addition, the present studies showed that the EDA was not only choose as nitrogen doping source but also played a key role in reduction.