In this study, the possibility of biodiesel fuel and oxygenated fuel(dimethoxy methane, DMM) was investigated as an alternative fuel for a naturally aspirated direct injection diesel engine. The smoke emission of blending fuel (diesel fuel 90vol-% + DMM 10vol-%) was reduced approximately 70% at 2500rpm, full load in comparison with the diesel fuel. Engine power and brake specific energy consumption showed no significant differences. But, NOx emission of biodiesel fuel and DMM blended fuel increased compared with commercial diesel fuel due to the oxygen component in the fuel. It was needed a NOx reduction counter plan that EGR method was used as a countermeasure for NOx reduction. It was found that simultaneous reduction of smoke and NOx emission was achieved with diesel fuel (95 vol-%) and DMM (5 vol-%) blended fuel and cooled EGR method (15%).

This research aims to analyze the potential possibility of the butyl ether (BE, oxygenates of di-ether group) as a fuel additives for a naturally aspirated direct injection diesel engine fuel. Compared with the diesel fuel, smoke emission decreased approximately 26% by applying the blended fuel(diesel fuel 80 vol-% + BE 20vol-%) at the engine speed of 2,500 rpm and with full engine load. There was none significant difference between the blended fuel and the diesel fuel on the power, torque, and brake specific energy consumption rate of the diesel engine. But, NOx emission from the blended fuel was higher than that of the commercial diesel fuel. As a counter plan, the EGR method was employed to reduce the NOx. We found the possible area where the simultaneous reduction of the smoke and the NOx emission from the diesel engine was achieved by applying the BE blended fuel and the cooled EGR method.

The study was conducted to evaluate the effects of microbial culture supplements on ruminal fermentation and fermentative quality of Italian ryegrass silage (IRGS) both in vitro and in situ. Three species of microbes (Lactobacillus casei (LC), Bacillus subtilis (BS), and Saccharomyces cerevisiae (SC)) were used in this study. They were applied to IRGS at 30 days after silage manufacture. Various items were measured using in vitro and in situ incubation technique after each microbial supplement was inoculated into IRGS at 0.5×104 CFU/g. In the first experiment, in vitro ruminal fermentation characteristics of IRGS were evaluated at 0, 12, 24, 48, and 72 hours after microbes were inoculated into IRGS. In the second experiment, in situ fermentation characteristics were investigated at 0, 1, 3, and 5 days after the inoculation of each microbial supplement. In vitro ruminal NH3-N content was significantly (p<0.05) increased in LC-, BS-, and SC-IRGS at 12 hrs post incubation compared to that in control IRGS. In vitro ruminal total VFA concentration and dry matter digestibility (DMD) of IRGS were not significantly difference among LC-, BS-, and SC-IRGS, although they were numerically increased in LC-IRGS than those of the other IRGS. In addition, this study evaluated the fermentation characteristics and in situ DMD of IRGS with the lapse of incubation time up to 5 days. Throughout the incubation times from 1 day to 5 days, the pH value was significantly (p<0.05) lower in BS-, LC-, and SC-IRGS than that in control IRGS. Lactate was significantly (p<0.05) higher, and significantly (p<0.05) butyrate was lower in LC-IRGS than that in other treatments at 0 day. It was higher (p<0.05) in control IRGS than that of BS-, LC-, and SC-IRGS at 1-5 days. In situ DMD tended to increase in BS-, LC-, and SC-IRGS compared to that in control IRGS. Especially, DMD was higher in SC-IRGS than that in other treatments at 0 day. It tended to be higher in LC-IRGS at all incubation time. Taken together, these results suggest that it might be useful to select a microorganism by considering the feeding time of IRGS to ruminants because organic acids and DMD of IRGS were affected by the incubation time of each microorganism with IRG silage, especially for L. casei decreased the content of acetate and butyrate in IRGS.

Biodiesel as alternative energy source of the traditional petroleum fuels has increased interest, because environmental pollution based exhaust emissions from vehicle became serious. The advantage of biodiesel produced from esterification of vegetable and animal oils can be used without the modification of existing diesel engine, but glycerin is generated by production process. In this study, the usability of non-esterification biodiesel as an alternative fuel was investigated in a indirect injection diesel engine. The non-esterification biodiesel has not generated glycerin in esterification process and reduced the 20 percent of cost because it has not used methanol in the production process. Experiments were conducted by using the 5, 10 and 20 percentage of biodiesel and 4 and 8 percentage of biodiesel with 1 and 2 percentage of WDP in baseline diesel fuel. The smoke emission of biodiesel was reduced in comparison with diesel fuel, but power, torque and brake specific energy consumption was similar to diesel fuel.

한우 송아지의 생후 환경스트레스에 대한 면역반응성 및 신바이오틱제제의 급여효과를 구명하기 위해서 출생 후부터 각 처리구별로 5두씩 배치하여 총10두(2처리×5두)를 대상으로 대조구(신바이오틱제제미투여)와 처리구(신바이오틱제제 투여구)로 배치하여 총 65일간(포유기간) 시험하였다. 송아지 체중은 대조구(21.4±2.51 kg - 57.0±12.83 kg)에 비해 신바이오틱제제 급여 처리구(22.0±2.12 kg - 53.2±4.32 kg) 개체간의 체중의 편차를 줄이는 역할을 하는 것으로 나타났다. Nitric oxide는 신바이오틱제제 처리구(12.52 μM/L-39.72 μM/L)가 대조구(19.68 μM/L-64.80uM/L)보다는 낮았으며, 코티졸 농도는 한우 송아지 신바이오틱제제 처리구에서 7일령, 45일령, 그리고 65일령에서 유의적으로 감소하였고(P<0.05), 혈중 Glutathione는 65일령에서 유의적으로 증가하였다(P<0.05). SOD의 농도는 신바이오틱제제 처리구의 28일령과 65일령에서 유의적으로 감소하였고(P<0.05), H2O2의 농도는 신바이오틱제제 처리구 45일령과 65일령에서 유의적으로 감소하였다(P<0.05). Interlukin-1β 농도는 대조구에서 28일령(43.26±4.40 pg/mL)과 처리구 21일령(24.68±3.20 pg/mL)에 가장 높았으며, 14일령, 28일령, 65일령의 신바이오틱제제 처리구에서는 유의적으로 낮았다. IL-2 농도는 대조구 28일령 (218±16.94 pg/mL)과 신바이오틱제제 처리구 7일령(174.60±11.60 pg/m)에서 각각 가장 높았고, 21일령 이후 처리구에서 유의적으로 감소하였다. IL-6 농도 또한 대조구 28일령(403.20±48.19 pg/mL)과, 신바이오틱제제 처리구 65일령( 238.20±15.63 pg/mL)에서 가장 높았으며, 21일령 이후 신바이오틱제제 처리구에서 유의적으로 낮았다. PGE2 농도는 대조구 45일령(3660±463.25 pg/mL)과 신바이오틱제제 처리구 45일령(1070±141.92 pg/mL)에서 각각 가장 높았으며, 14일령 이후 신바이오틱 제제 처리구에서 유의적으로 낮았다. 앞의 결과를 종합해보면, 신바이오틱제제의 경구투여로 생체내의 싸이토카인의 체내 균형조절 및 면역 염증반응을 억제하는 데 관여하는 것으로 보인다. 그리고 신바이오틱제제의 급여로 분만 직후 한우 송아지의 체내의 변화가 체외의 변화로 이어져 가축의 성장촉진 및 열악한 주변환경 극복 등에 보다 더 확실한 효과를 기대하기 위해서는 신바이오틱제제의 급여기간을 늘릴 필요가 있을 것으로 사료된다.