• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 추계학술대회논문집B
• /
• pp.818-823
• /
• 2001

Because the exhaust emissions from automobiles are increased, our environment is faced with very serious problems related to the air pollution in these days. In particular, the exhaust emissions of diesel engine are recognized main cause which influenced environment strong. Lots of researcher have been attempted to develop various alternative fuel on purpose to reduce these harmful emissions. In this study, the potential possibility of esterfied rice bran oil which is a kind of biodiesel fuel was investigated as an alternative fuel for diesel engine. And, we tried to analysis not only total hydrocarbon but hydrocarbon components from $C_1$ to $C_6$ in exhaust gas using gas chromatography to seek the reason for remarkable reduction of exhaust emission. Individual hydrocarbon$(C_1\simC_6)$ as well as total hydrocarbon of biodiesel fuel is reduced remarkably than that of diesel fuel in this experiment.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 1998년도 특별강연 및 춘계학술발표 개요집
• /
• pp.150-154
• /
• 1998

The purpose of this paper is to investigate optimum welding conditions of STS 304 thin sheet by GTA welding and control 6 $\delta$--fenite which is harmful in mechanical processing, corrosion problem and can be formed brittle a phase in using long term at high temperature. One series of automatic welds was made using argon plus 10, 20, 30 % nitrogen to ensure a fully austenite deposit. Results obtained were summarized as follows: 1) 6 $\sigma$ferrite content in the weld metals is influenced largely by the nitrogen content. 2) Additions of nitrogen to the shielding gas can significantly reduce the amount of retained delta ferrite and result in an increase in hot cracking. 3) Bead width was increased when Ar + $N_2$ shielding gas was used and travel speed was increased. 4) Ar+$N_2$ shielding gas made weld metal ductile and reduce 6 -$\delta$-ferrite.

• 환경위생공학
• /
• 제16권1호
• /
• pp.47-52
• /
• 2001

In this study, we focused on typically problematic sulfide compounds Gas samples were captured at Unjung-ding landfill site in Metropolitan Kwangju with flux chamber and floating chamber, and analyzed for the amount of hydrogen sulfide($H_2S$), dimethyl sulfide $((CH_3)_2S)$ and dimethyl disulfide$((CH_3)_2S_2)$. From the gas pipe, landfill surface and leachate treatment plant, estimated total amount of $H_2S$ emission are 12.6ton/yr, 0.01ton/yr and 1.04ton/yr; estimated total amount of $((CH_3)_2S)$ 30.7ton/yr, 0.08ton/yr and 1.72ton/yr; and estimated total amount of ($((CH_3)_2S_2)$ 2.2tom/yr, 0.02ton/yr and 1.03ton/yr, respectively. Further in-depth study on co-relation between age, packing characteristics, temperature and humidity of landfill site and gas emission characteristics is needed.

• 한국기계기술학회지
• /
• 제13권4호
• /
• pp.101-108
• /
• 2011

On cold start operation of an SI engine, a catalyst shows poor performance before it reaches activation temperature. Therefore, fast warmup of the catalyst is very crucial to reduce harmful emissions. In this study, an appropriate control strategy is investigated to increase exhaust gas temperature through changes of spark timing. Combustion stability is also considered at the same time. Exhaust gas temperature and pressure of combustion chamber are measured to investigate the effects of spark timings on cold start and idle performance. Experiments showed that retarded spark timing promotes the combustion at the end of expansion stroke and increases exhaust gas temperature during cold start.

• 한국가스학회지
• /
• 제3권1호
• /
• pp.8-13
• /
• 1999

산업안전보건법 제49조 2에 의거하여 유해$\cdot$위험설비를 보유한 사업장의 사업주는 당해 설비로부터 위험물질의 누출, 화재, 폭발 등으로 인하여 사업장내의 근로자에게 즉시 피해를 주거나 사업장 인근지역에 피해를 줄 수 있는 중대산업사고를 예방하기 위해 사업장이 공정안전관리를 시행해야 한다. 그러나 국내의 많은 화학관련 기업들은 안전관리에 많은 시간과 인력을 투자하는 경향이 증가하였으나 아직까지는 대기업에 소속된 화학공장에 국한되어 있으며, 특히 IMF시대에 중$\cdot$소기업 형태의 화학공장은 자금압박 등의 어려움으로 생산성 향상에 급급한 나머지 안전에 대한 인적$\cdot$물적 투자를 꺼려하는 경향이 지배적이다. 따라서 중$\cdot$소 화학공장이 갖고 있는 경제적, 현실적 문제점을 보완함과 동시에 능동적으로 공정의 안전성을 확보하는데 도움을 줄 수 있는 공정안전관리 시스템을 구축하였다.

• 한국추진공학회지
• /
• 제24권4호
• /
• pp.41-47
• /
• 2020

본 연구에서는 염소가스 등 유해가스의 발생을 줄이고 질소가스 방출을 증가시키는 친환경 추진제 조성개발을 목표로 한다. 이에 고체 추진제에 일반적으로 사용되는 AP(Ammonium Perchlorate)와 Al(Aluminium)를 대신하여 저탄소 고질소 물질인 GUDN(N-Guanylurea dinitramide)과 BTATz(3,6-bis(1H-1,2,3,4-tetrazol-5-ylamino)-1,2,4,5-tetrazine)를 사용하였다. 제조된 추진제는 기계적 및 연소 특성, 성능 그리고 AGARD 연기등급을 분석하였다. AP/Al 추진제에 비해 GUDN/BTATz추진제는 기계적 성질과 연소 속도가 감소하는 경향을 나타내었다. 또한, 4인치표준모타 제작 후 지상연소 시험 결과 GUDN/BTATz추진제 연소 시 성능은 감소하였으나, 염소가스 등의 유해 가스를 줄여 2차 연기 등급도 개선됨을 확인할 수 있었다.

• 한국의류학회지
• /
• 제35권11호
• /
• pp.1297-1308
• /
• 2011

This research investigates the application of ZnO (zinc oxide) nanoparticles and $TiO_2$ (titanium dioxide) nanoparticles to polypropylene nonwoven fabrics via an electrospinning technique for the development of textile materials that can decompose harmful gases. To fabricate uniform ZnO nanocomposite fibers, two types of ZnO nanoparticles were applied. Colloidal $TiO_2$ nanoparticles were chosen to fabricate $TiO_2$ nano- composite fibers. ZnO/poly(vinyl alcohol) (PVA) and $TiO_2$/PVA nanocomposite fibers were electrospun under a variety of conditions that include various feed rates, electric voltages, and capillary diameters. The morphology of electrospun nanocomposite fibers was examined with a field-emission scanning electron micro- scope and a transmission electron microscope. Decomposition efficiency of gaseous materials (formaldehyde, ammonia, toluene, benzene, nitrogen dioxide, sulfur dioxide) by nanocomposite fiber webs with 3wt% nano-particles (ZnO or $TiO_2$) and 7$g/m^2$ web area density was assessed. This study shows that ZnO nanoparticles in colloid were more suitable for fabricating nanocomposite fibers in which nanoparticles are evenly dispersed than in powder. A heat treatment was applied to water-soluble PVA nanofiber webs in order to stabilize the electrospun nanocomposite fibrous structure against dissolution in water. ZnO/PVA and $TiO_2$/PVA nanofiber webs exhibited a range of degradation efficiency for different types of gases. For nitrogen dioxide, the degradation efficiency was 92.2% for ZnO nanocomposite fiber web and 87% for $TiO_2$ nanocomposite fiber web after 20 hours of UV light irradiation. The results indicate that ZnO/PVA and $TiO_2$/PVA nano- composite fiber webs have possible uses in functional textiles that can decompose harmful gases.

• 한국추진공학회지
• /
• 제18권2호
• /
• pp.86-92
• /
• 2014

나로우주센터에 구축되는 연소기 연소시험설비(CCTF)에는 한국형발사체(KSLV-II)에 적용된 터보펌프식 엔진의 가스발생기 시험시 생성되는 연료과잉가스를 연소시키기 위한 후연소시스템이 포함되어 있다. 후연소시스템은 $O_2$와 $CH_4$ 가스를 공급받아 연료과잉가스를 소모시킨다. 본 연구는 연소기 연소시험설비의 상세설계 자료를 바탕으로 후연소시스템의 가스공급시스템에 대해 AMESim 상용프로그램을 이용하여 해석하였다. 그 결과 상세설계에 적용된 레귤레이터, 공급배관, 오리피스크기 등으로 가스사용량을 예측하고, 상세설계의 타당성을 검증하였다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회B
• /
• pp.2327-2332
• /
• 2007

This study investigates on the inhalation force improvements of hood consisted one of the local ventilation systems attached the new device named as gas-guidance-device for removed a pollution source. The numerical method applying finite element method is calculated the velocity and pressure distributions of a moving fluid at the beginning and the inside of a hood with and without the gas-guidance-device in hood. And, the experimental study is measured the wind velocity using the anemometer at the same condition of numerical study. Also, the optimum shape of gas-guidance-device which is suitable for hood shape derived from the numerical and experimental results. The results of this study is supplied the important data to an industrial field for control of a pollution source in the engineering aspect. Moreover, the introduced technique of hood attached the gas-guidance-device is very useful to remove the harmful materials such as dust and waste happened in the manufacturing factory.

• 한국자동차공학회논문집
• /
• 제15권6호
• /
• pp.159-164
• /
• 2007

The purpose of this study is to reduce harmful emission gases in the range of stable combustion without loss of a thermal efficiency. Therefore, effects of both exhaust gas recirculation(EGR) and synthetic gas addition on engine performance and emission were investigated in a gasoline engine. Synthetic gas(syngas), which is in general prepared from reforming gasoline, was utilized in order to promote stable combustion. The major components of syngas are H2, CO and $N_2$ gases. The percentage of syngas addition was changed from 0 to 30% in energy fraction and EGR rate was varied up to 30%. As a result, $COV_{IMEP}$ as a parameter of combustion stability was decreased and THC/$NO_X$ emissions were reduced with the increase of syngas addition. And $COV_{IMEP}$ was increased with the increase of EGR but $NO_X$ emission was greatly reduced. In addition, under the region where the EGR rate is around 20%, thermal efficiency was improved.