• 한국자동차공학회논문집
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• 제12권6호
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• pp.16-22
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• 2004

Dimethyl Ether (DME) has been considered as one of the most attractive alternative fuels for a compression ignition engine. The major advantage of DME-fuelled engine is a great potential for soot-free combustion without sacrificing an inherent high thermal efficiency of diesel engine, despite a necessity for modification of the conventional fuel injection system. An experimental study on DME and conventional diesel sprays was conducted by employing a common-rail type fuel injection system with a 5-holes sac type nozzle, including a constant volume vessel pressurized with nitrogen gas. The injection rates of DME and diesel fuel were recorded with the Bosch type injection rate meter. The injection delay of DME was shorter than that of diesel fuel. The measured injection rates of DME and diesel fuel were correlated with spray penetrations. The prediction method of spray penetration was established using the injection rates, which was verified with the Dent's penetration model and found to agree well for DME case.

• 소성∙가공
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• 제21권1호
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• pp.36-41
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• 2012

Gas Assisted Injection Molding is a relatively new low-pressure injection molding technique that provides benefits such as reduced part warpage, excellent surface quality without shrink marks, greater design flexibility, etc. In the gas assisted injection molding process, the injected pressurized nitrogen gas flows through designed gas channels and forms hollow sections within the part. However, due to the characteristics of the gas, the design of the gas channels which are the paths for the injected gas is important in order to avoid defects such as gas blowout, fingering, etc. Therefore, in this study, the gas channel design for gas assisted injection molding of exterior display panels was conducted by examining the results of three CAE analyses. The designed gas channel was verified by conducting tryouts using a 450 ton injection molding machine with 3-stage pressure controlled gas kit. In addition, the hollow shapes which were formed by the gas with the installed gas channels were examined by examining the cross sections of the prototypes that were produced. As a result, it was found that exterior display panels can be produced without any defect by applying the gas assisted injection molding technique.

• 한국분무공학회지
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• 제17권4호
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• pp.178-184
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• 2012

The aim of this study was to compare the spray characteristics of a typical fuel (100% diesel, DME) and diesel-DME blended fuel in a constant volume combustion chamber (CVCC). The typical fuel (100% diesel, DME) and diesel-DME blended fuel spray characteristics were investigated at various ambient pressures (pressurized nitrogen) and fuel injection pressures using a common rail fuel injection system when the fuel mixture ratio was varied. The fuel injection quantity and spray characteristics were measured including spray shape, penetration length, and spray angle. Common types of injectors were used.

• International Journal of Automotive Technology
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• 제2권4호
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• pp.123-133
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• 2001

An important goal in diesel engine research is the development of a means to reduce the emission of oxides of nitrogen ($NO_x$) and soot particulate. A phenomenological model based on the multizone concept is used in the current paper to analyze and compare the effects of exhaust gas recirculation (EGR) and split fuel injection on emission from a compression-ignited, direct-injection engine. The present results show that $NO_x$ can be reduced with a minimum penalty of soot particle emission with cooled EGR. Compared with EGR, split fuel injection has a higher soot penalty at a given level of $NO_x$ reduction.

• 한국연소학회지
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• 제12권2호
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• pp.20-25
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• 2007

The supersonic combustion experiments are carried out using T3 free-piston shock tunnel. Hydrogen Fuel is injected in the cavity parallel with air(or nitrogen) flow. The equivalence ratios in this study are 0.132 and 0.447. Experimental measurements use OH-PLIF near the cavity and pressures in the combustor. For parallel fuel injection case, direct fuel add into cavity leads to increase of cavity pressure. And Flame exists just near the bottom wall for low equivalent ratio. There is no flame in the cavity because of no mixing in it. Compared to the inclined fuel injection, ignition delay length is longer for low equivalence ratio in both case. OH distribution is not a single line but a repeatable fluctuation flame structure by turbulence. Pressure distributions have nothing to do with the fuel injection position.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2007년도 제34회 KOSCO SYMPOSIUM 논문집
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• pp.31-36
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• 2007

The supersonic combustion experiments are carried out using T3 free-piston shock tunnel. Hydrogen Fuel is injected in the cavity parallel with air(or nitrogen fuel) flow. The equivalence ratios in this study are 0.132 and 0.447. Experimental measurements use OH-PLIF near the cavity and pressures in the combustor. For parallel fuel injection case, direct fuel add into cavity leads to increase of cavity pressure. And Flame exists just near the bottom wall for low equivalent ratio. There is no flame in the cavity because of no mixing in it. Compared to the inclined fuel injection, ignition delay length is longer for low equivalence ratio in both case. OH distribution is not a single line but a repeatable fluctuation flame structure by turbulence. Pressure distributions have nothing to do with the fuel injection position.

• 한국자동차공학회논문집
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• 제12권4호
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• pp.31-35
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• 2004

A new combustion strategy called LIFC(Late Injection ＆ Fast Combustion) was developed for simultaneous reduction of particulate matter(PM) and nitrogen oxides(NOx) in exhaust emission of diesel engines, In this study, effects of injection timing and injection pressure under relatively high EGR rate were investigated. The experiments were conducted in a conventional engine over a range of commercial engine speed. The test engine could be operated in LIFC up to 2000rpm / bmep 5 bar condition with significant reduction of NOx and PM. The experimental results showed potential for the mechanism of the simultaneous reduction of NOx and PM from HSDI diesel engines.

• 자원리싸이클링
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• 제1권1호
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• pp.37-43
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• 1992

The submerged injection smelting process was performed to recover Zn and Pb from steel dust throuth vaporization and to investigate the effect of temperature, slag composition, injection time, gas flow rate, etc. on the recoveries of valuable metals. The results show that vaporation rates of zinc and lead increased at higher temperture and higher moral ratio of ferrous to ferric oxides. In the initial stage of submerged injection of nitrogen gas, the molten slags of the dust have high value of molar ratio of $Fe^{2+}$/$Fe^{3+}$ and hence zinc and lead can be effectively recovered.

• 한국축산시설환경학회지
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• 제18권sup호
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• pp.73-80
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• 2012

가축분뇨 중의 질소성분이 불필요하게 대기중으로 휘산되어 환경오염을 일으키거나 가축분뇨의 비료 가치를 저하시키는 것을 줄여주기 위해서는 가축분뇨 처리단계 별 질소손실 기작 및 조건을 올바르게 이해할 필요가 있다. 각 축종별 우리나라의 전형적인 축사시설 및 가축분뇨 처리형태를 기준으로 가축분뇨에 함유된 질소가 토양에 살포되어 작물에 의해 이용될 수 있는 비율을 산정한 결과는 다음과 같다. 1. 슬러리 형태로 수거한 돈분뇨를 퇴비화 한 후 토양에 표면살포했을 경우 시비 후 2년 이 경과한 시점에서 작물이 이용 가능한 질소 성분은 배설된 분뇨에 함유된 총질소 성분의 27% 수준이다. 2. 슬러리 형태로 수거한 돈분뇨를 혐기소화 한 후 토양 표면에 살포한 상태에서 2년 후에 작물이 이용 가능한 질소는 분뇨중 총 질소의 29%이며, 혐기소화 한 소화폐액을 토양주입(Injection)에 의해 살포할 경우 분뇨중 총질소의 54%가 2년 후 작물에 의해 이용 가능하다. 이러한 결과는 토양주입이 가축분뇨 토양살포 시 휘산되는 암모니아를 저감시키는데 매우 효율이 높음을 입증하는 좋은 예라고 볼 수 있다. 3. 깔짚우사에서 수거한 한우 및 젖소 분뇨를 퇴비화한 후 토양 살포를 할 경우 3년이 경과한 시점에 작물이 이용 가능한 질소는 분뇨 중 총질소의 18% 수준이다. 4. 계분을 퇴비화한 후 토양 살포를 할 경우 2년이 경과한 시점에 작물이 이용 가능한 질소는 분뇨 중 총질소의 18% 수준으로 계산되었다.

• Biomolecules & Therapeutics
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• 제3권4호
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• pp.260-265
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• 1995

In an attempt to define the early biochemical determinants that participate in the pathogenesis of glycerol-induced nephrotoxicity, especially focusing on oxygen free radicals, we studied malondialdehyde (MDA) level and the activities of catalase and superoxide dismutase in the renal cortex of rats, and the concentrations of blood urea nitrogen(BUH) and serum creatinine of rats at 24hr after the injection of a 50% solution of glycerol. Sprague-Dawley albino rats weighing 240 to 260 mg were injected intramuscularly with a 50% solution of glycerol(2 mι/kg, 4 mι/kg and 8 mι/kg). The group treated with glycerol showed significantlv higher MDA level and catalase activity, lower SOD activity and higher BUN and serum creatinine concentrations at 24 hr after the injection as compared to those of control group. These results suggest that the excessive oxygen free radicals resulting from the depression of SOD activity is an important determinant in the pathogenesis of glycerol-induced nephrotoxicity.