• Transactions of the Korean hydrogen and new energy society
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• v.29 no.1
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• pp.81-89
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• 2018

Fuel blend technique is one of the most effective way of using biomass to replace the coal. Many studies on combustion characteristics with coal and biomass blends have been conducted. In this study, char reactivity and emission characteristics of coal (Suek) and biomass (EFB) blends has been investigated by TGA and DTF to evaluate the applicability of the pre-treated (torrefaction, ash removal technology) EFB to pulverized coal boiler. In all blending cases, char reactivity improved as the blending ratio increases (10, 20, and 30%), especially torrefied EFB blended at 30%. Also, unburned carbon decreased as the blending ratio increases in all types of EFB. NOx emission showed the increase and decrease characteristics according to the content of fuel-N of raw EFB and torrefied EFB. But the amount of NOx emission at ashless EFB blends is greater than that of Suek despite of lower fuel-N. It indicated that co-firing effect of using the pretreatment biomass fuel is relatively better than those of the untreated biomass fuel about char reactivity and emission characteristics.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.10
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• pp.637-644
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• 2016

The purpose of this study is to understand the characteristics of unburned carbon (UBC) and NOx emissions for pulverized coal when air staging combustion is applied. A two-staged drop tube furnace capable of applying air staging combustion was designed and installed. The combustion of sub-bituminous (Tanito) has been investigated. UBC and the NOx concentration were measured under various temperatures and stoichiometric ratios in unstaged and staged combustion. As a result, UBC decreased and the NOx concentration increased with an increase in stoichiometric ratio and temperature. In particular, the NOx reduction mechanism was activated when the temperature in the fuel rich zone increased. Both UBC and the NOx concentration decreased as the temperature increased in the fuel rich zone. A high NOx reduction effect was obtained, compared to the UBC increase, when the air staging technique was applied.

• Journal of Energy Engineering
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• v.20 no.3
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• pp.191-199
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• 2011

The char burn-out and NOx emissions from sub-bituminous coal were investigated in drop tube furnace under $O_2/N_2$ and $O_2/CO_2$ environments with different $O_2$ concentrations of 12, 21 and 31%. Results show that the char burn-out rate is faster as $O_2$ concentration increases higher and char burn-out rate under $O_2/CO_2$ decreases due to the lower oxygen diffusion into coal surface through the $CO_2$ rich boundary layer. NO concentration increases with increasing $O_2$ concentration, but declines at $O_2$ concentration of 31%. Meanwhile, NO emission indexes decreases monotonically with increasing $O_2$ concentration, which indicates that more NO reduction occurs with higher $O_2$ concentration probably due to greater HCN formation. For all conditions of $O_2$ concentration, the NO concentration under $O_2/N_2$ maintains higher than those of $O_2/CO_2$ due to presence of thermal NO.

• Parasites, Hosts and Diseases
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• v.34 no.1
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• pp.49-58
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• 1996

Characterization of a purified proteinase from T4chomoncs uoginalis was carried out using bacitracin-sepharose affinity chromatography. Trichomonos uqginolis KT-9 isolate was used as a source of eye study Proteinase activity was determined using Bz-Pro- Phe-Arg-Nan as the substrate. Optimum pH for the purified proteinase activity was 7.0 and 6.0, 9.0 with DTT. Optimum temperature was 37℃ and isoelectric point was 7.2 Activity of this proteinase was inhibited by E-64, antipain, leupeptin, Hg2+ and Zn2+ and activated by DTT and cysteine. Activity of the purified proteinase was visualized by gelatin SDS- PAGE. The gelatinolytic activity of the purified proteinase was inhibited by E-64, antipain, leupeptin, and IAA, but not by PMSF and EDTA. On SDS-PAGE, the molecular weight of the purified proteinase was 60,000 daltons. Sera of rabbits infected with T. vaginalis reacted specifically in immunoblots with this proteinase. These results indicate that 60 kDa of purified proteinase was cysteine proteinase with antigenicity.