In this research, a precipitation method was used to synthesize β-Ga2O3 powders with various particle morphologies and sizes under varying precipitation conditions, such as gallium nitrate concentration, pH, and aging temperature, using ammonium hydroxide and ammonium carbonate as precipitants. The obtained powders were characterized in detail by XRD, SEM, FT-IR, and TG-DSC. From the TG-DSC result, GaOOH phase was transformed to β-Ga2O3 at around 742˚C, and weight loss percent was about 14 % when NH4OH was used as a precipitant. Also, β-Ga2O3 formed at 749˚C and weight loss percent was about 15 % when (NH)2CO3 was used as a precipitant. XRD results showed that the obtained Ga2O3 had pure monoclinic phase in both cases. When (NH)2CO3 was used as a precipitant, the particle shape changed and became irregular. The range of particle size was about 500nm-4μm based on various concentrations of gallium nitrate solution with NH4OH. The particle size was increased from 1-2μm to 3-4μm and particle shape was changed from spherical to bar type by increasing aging temperature over 80˚C.

Ink-jet printing technology has been widely attractive due to its facility for direct and fine printing on various substrates. Recent studies have focused on expanding the application of ink-jet printing technology from general consumer use and design companies to the prototype production of precision parts and parts manufacturing. The use of ink-jet printing technology in decorated tableware, tiles, and other ceramic products also has many advantages. The printing process is fast and can be adaptable to various kinds of objects because there is no direct contact point between the printer and the substrates to be printed. For application to ceramic product decoration, inks containing highly dispersed inorganic nano-pigments are required. Here we report the synthesis and characterization of blue CoAl2O4 nanopigment for ink-jet printing. Blue ceramic ink based on the obtained CoAl2O4 pigment was prepared by dissolving CoAl2O4 pigment in a mixed solution of ethylene glycol and ethanol with volume ratios of 7:3 and 8:2, respectively, to obtain the appropriate viscosity for ink-jet printing. The ink solution contained 15 wt% of CoAl2O4 pigment and Cetyltrimethyl ammonium bromide(CTAB) and Sodium dodecyl sulfate(SDS) as dispersive agents. The prepared blue ceramic ink was stably jetted and formed a sphere-shaped droplet from an ink-jet printer.

We investigated phase separation by adding different concentrations of MTBE, to the mixtures of naphtha, ethanol and water. The phase separation temperatures of the Naphtha-Ethanol-Water solutions have dropped when the concentration of MTBE increases more. When adding IPA and IBA to the solutions of Gasoline-Ethanol and Gasoline base-Ethanol individually, IBA shows lower temperatures of phase separation than IPA, and it shows synergistic effect when mixtures of IPA and IBA is applied.

Gasohol, which is combined solution of gasoline and ethanol, is difficult to apply to the field, because it usually brings phase separation by mingling of water. We investigated phase separation by adding different concentrations of "Ethanol", anhydrous and fermentative, to "Gasolines", gasoline, gasoline base and naphtha, Placing ethanol itself open to the air, the concentrations of water are increased in length of time. The phase separation temperatures of the gasolines-ethanol solutions have dropped in the following order : gasoline, gasoline base and naphtha. When adding water to the solutions of gasolines and anhydrous ethanol, the temperatures of phase separation is higher when the concentration of water increases more. Thus, it is obvious that the water is sensitive in phase separation.

원자력연구원에서는 우라늄으로 오염된 콘크리트 폐기물을 원자력시설 중 방사성 폐기물저장고에 임시 보관되고 있다. 그러나 앞으로의 방사성 폐기물은 중･저준위 방사성 폐기물처리시설로 보내야하는 제도로 바뀌게 되므로 계속적인 임시보관은 어려워짐에 방사성 폐기물량을 감소시키는 방향으로 가야한다고 제시되고 있다. 방사성 원소로 오염된 콘크리트의 제염 연구는 지금가지 거의 수행되지 않았고, 단지 물리적인 분리법으로 해체하는 방법들만 제시되었다. 우라늄으로 오염된 콘크리트를 연간 100드럼 제염하기 위한 실용규모로 구축하여 시범적인 운영 결과 자체 처분 농도 이하로 대략 65%정도 처리가 가능하였다. 그러나 실제 정상적으로 연간 100드럼의 콘크리트를 처리하기 위해서는 장치의 문제점이 발견되어 개선이 필요하다. 또한, 미세 입자를 방사성 폐기물로 처리하지 않고 제염하여 처리효율을 높이는 연구를 진행하고 있다.

The aim of this study was to evaluate various methods for producing high-quality fuel pellets using rape stalk (RS), which is an agricultural waste. RS was used as a raw material for pellets production after three treatments [distilled water (DW), sulfuric acid (AC), sodium hydroxide (AK) solutions]. Then, fabricated pellets with two binder additions [ rapeseed flour (RF), coffee waste (CW)] were examined to evaluate their fuel qualities. Results showed that binder additions (RF, CW) improve the durability and higher heating value for RS-based pellets. The addition of CW greatly decreased ash content for fabricated pellets. Also, all immersion treatments improved all fuel qualities compared to non-immersed treatment. Particularly, DW-immersion had favorable influences on the increases of higher heating value and durability. Two immersion treatments (AC, AK solution) positively influenced the improvements of bulk density and ash content for fabricated pellets. However, they were required to rinse the residue existed on the RS, and consequently the use of DW-immersion might be the most beneficial way to improve the qualities of RS-based pellets. All qualities of the pellets were acceptable for the European agropellet standards (A- or B-grade). Hence, RS can be used as a raw material for the production of agropellets while outdoor exposure of RS or mixing RS with CW or wood sawdust might be help to better agropellets qualities.

Over the past few decades, many scientists and environmental activists emphasized the importance of sustainable society and warned the global warming. As one of efforts to achieve the sustainable society and maintain no more of global warming, the RDF (Refuse Derived Fuel) production from domestic solid is taken into account seriously in Daejeon, Korea. Currently, the pay per throw system is active from 1995 and is quite stabilized. Recyclable wastes such as metal scraps, glass, papers, and fibers like clothes should be discarded separately and not be mixed with other types of waste being disposed of eventually. To assess the potential for the conversion of domestic solid waste into a heat source, i.e., RDF, the proximate analysis, the classification into 10 components, and the calculation of heat value based on the result of the elemental analysis were performed. Based on the preceding analysis, the domestic solid waste produced daily in Daejeon, Korea has a potential for conversion into an alternative energy source, RDF in technical aspect. Proper blending of combustibles, however, is necessary to enhance the heating value of RDF being produced and to be more viable in economic aspect.