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Cooled EGR이 농도성층화가 존재하는 DME HCCI 엔진 연소에 미치는 영향에 관한 수치해석 연구
Soyol-Erdene,정동원(Dongwon Jeong),권오석(Oseock Kwon),임옥택(Ocktaeck Lim) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
Homogeneous charge compression ignition (HCCI) engines have the potential to provide both diesel-like efficiency and very low emissions of nitrogen oxides (NOx) and particulates. Before this potential can be realized, however, extending HCCI operation to high loads must be resolved by lowering the pressure-rise rate. For lowering the steep pressure rise rate occurred in high load, cooled exhaust-gas recirculation (Cooled EGR) and fuel stratification of pre-mixture in cylinder are recommended as one of the effective ways. Conduct numerical analysis to combination of cooled EGR and fuel stratification for confirming enhanced effect to lowering pressure rise rate, after indentifying each effect on extending HCCI operating ranges. Fuelling width in cylinder is φ=0.15 and CO₂ is used as a simulated cooled EGR. DME which has a characteristic of two-stage ignition is used as a fuel.
Soyol-Erdene, Tseren-Ochir,Huh, Youngsook,Hong, Sungmin,Hur, Soon Do American Chemical Society 2011 Environmental science & technology Vol.45 No.14
<P>Antarctic snow preserves an atmospheric archive that enables the study of global atmospheric changes and anthropogenic disturbances from the past. We report atmospheric deposition rates of platinum group elements (PGEs) in Antarctica during the last ∼50 years based on determinations of Pt, Ir, and Rh in snow samples collected from Queen Maud Land, East Antarctica to evaluate changes in the global atmospheric budget of these noble metals. The 50-year average PGE concentrations in Antarctic snow were 17 fg g<SUP>–1</SUP> (4.7–76 fg g<SUP>–1</SUP>) for Pt, 0.12 fg g<SUP>–1</SUP> (<0.05–0.34 fg g<SUP>–1</SUP>) for Ir, and 0.71 fg g<SUP>–1</SUP> (0.12–8.8 fg g<SUP>–1</SUP>) for Rh. The concentration peaks for Pt, Ir, and Rh were observed at depths corresponding to volcanic eruption periods, indicating that PGEs can be used as a good tracer of volcanic activity in the past. A significant increase in concentrations and crustal enrichment factors for Pt and a slight enhancement in enrichment factors for Rh were observed after the 1980s. This suggests that there has been large-scale atmospheric pollution for Pt and probably for Rh since the 1980s, which may be attributed to the increasing emissions of these metals from anthropogenic sources such as automobile catalysts and metal production processes.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/esthag/2011/esthag.2011.45.issue-14/es2005732/production/images/medium/es-2011-005732_0003.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/es2005732'>ACS Electronic Supporting Info</A></P>
Sources and fluxes of Pt, Ir and REE in the Seoul metropolitan area through wet scavenging processes
Soyol-Erdene, Tseren-Ochir,Han, Yeongcheol,Lee, Borom,Huh, Youngsook Elsevier 2011 Atmospheric environment Vol.45 No.11
<P><B>Abstract</B></P><P>Platinum group elements (PGEs: Pt and Ir) and rare earth elements (REEs) were analyzed in rainwater samples collected in Seoul during the summer of 2008 to identify their sources and quantify their wet-deposition fluxes to the Earth’s surface environment. Major (Na, K, Mg, Ca, NH<SUB>4</SUB><SUP>+</SUP>, SO<SUB>4</SUB><SUP>2−</SUP>, NO<SUB>3</SUB><SUP>−</SUP>, Cl<SUP>−</SUP> and F<SUP>−</SUP>) and minor (Fe, Ba, Y and Hf) elements were also measured to facilitate interpretation. Evaluation of elemental correlations, crustal enrichment factors, Ir/Pt ratios and REE patterns indicated meteoric/volcanic sources for Pt and Ir and additional anthropogenic sources for Pt. REEs were predominantly of crustal origin. The relationship between concentrations and rainfall indicated that below-cloud scavenging (wash-out) was the main scavenging mechanism for most elements. The wet-deposition fluxes in Seoul were higher than those recorded in polar ice cores for Pt and Ir and were comparable to those from other rainwater studies of REEs in East Asia.</P> <P><B>Research highlights</B></P><P>► We identify the sources and quantify the wet-deposition fluxes of Pt, Ir and REE. ► Pt and Ir had meteoric/volcanic sources and additional anthropogenic sources for Pt. ► REEs were predominantly of crustal origin. ► Ir and REE were removed by below-cloud scavenging (wash-out). ► The wet-deposition fluxes in Seoul were higher than in polar ice cores for Pt and Ir.</P>
Evidence of Global-Scale As, Mo, Sb, and Tl Atmospheric Pollution in the Antarctic Snow
Hong, Sungmin,Soyol-Erdene, Tseren-Ochir,Hwang, Hee Jin,Hong, Sang Bum,Hur, Soon Do,Motoyama, Hidaeki American Chemical Society 2012 Environmental science & technology Vol.46 No.21
<P>We report the first comprehensive and reliable time series for As, Mo, Sb, and Tl in the snowpack from Dome Fuji in the central East Antarctic Plateau. Our results show significant enrichment of these elements due to either anthropogenic activities or large volcanic eruptions during the past 50 years. With respect to the values reported from 1960 to 1964, we observed the maximum increases in crustal enrichment factors (EFs) for As (a factor of ∼15), Mo (∼4), Sb (∼4), and Tl (∼2) during the period between the 1970s and 1990s, reflecting the global dispersion of anthropogenic pollutants of these elements, even to the most remote areas on Earth. Such enrichments are likely related to emissions of trace elements from nonferrous metal smelting and fossil fuel combustion processes in South America, especially in Chile. A drastic decrease in the As concentration and its EF values was observed after the year 2000 in response to the introduction of environmental regulations in the 1990s to reduce As emissions from the copper industry, primarily in Chile. The observed decrease suggests that governmental regulations for pollution control are effective in reducing air pollution at both the regional and global level.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/esthag/2012/esthag.2012.46.issue-21/es303086c/production/images/medium/es-2012-03086c_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/es303086c'>ACS Electronic Supporting Info</A></P>