• Journal of Environmental Health Sciences
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• v.33 no.4
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• pp.250-254
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• 2007

The reduction efficiency of air cleaner on particulate contaminants such as dust, airborne bacteria and fungi distributed in the office was relatively higher in case of office with workers than office without workers. This result would be attributed to workers' activities and physical characteristics of particulate contaminants. The air cleaner decreased a concentration of airborne bacteria more than airborne fungi, which implicates that difference of dust adsorption between airborne bacteria and fungi would affect an operation efficiency of air cleaner.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.2
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• pp.133-143
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• 2003

Numerous evidence have been reported that fine particulate matters can play an important role in threatening human health. Recently concerns on fine particle pollution from various engines may require re-examination of particulate emission standards. The particles emitted by most diesel engines are mainly divided into their size ranges such as Dp< 50 nm and 50 nm< Dp< 1,000 nm. In this work, the number concentration and the size distribution of fine particles emitted from an exhaust manifold of a railroad diesel engine were measured under load test conditions using a scanning mobility particle sizer (SMPS). The fine particles observed were within the range of 7 to 304 nm under different load conditions with two different dilution ratios. The fine particles exhibited unique patterns showing bimodal shapes in size distribution.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.3
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• pp.66-74
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• 2004

DPF technology has been considered as one of the most effective methods for reducing diesel particulate emission. PSA Peugeot Citroen introduced the DPF equipped diesel passenger car, Peugeot 607 HDI Sedan, in 2000 for the first time in the world, in which SiC filter, an oxidation catalyst, cerium based fuel born catalyst and post-injection technology were used for PM regeneration. In the present study, the characteristics of the Peugeot 607 DPF system were studied on chassis dynamometer and real road driving conditions. The change of emissions and fuel economy during 80,000km operation were also tested. Additionally, ash contents accumulated in the DPF filter was analyzed and particle size distributions was investigated after running of 80,000km.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.1 no.2
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• pp.154-163
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• 1991

Particulate matter exposure leva1 of welders and grinding workers was evaluated in Banwol and Changwon industry complexes. Full period single sample and full period consecutive samples were collected with personal air samplers attached to workers. Compliance difference with 8-hour time weighted average (TWA) was compared by Korean strategy and the classification system recommended by OHSA for employee exposure to particulates. And difference of compliance was compared according to precision of measurement and analysis (total precision). Compliance rate was depended on the total precision, therefore, quality control of measurement and analysis was important.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.6
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• pp.729-738
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• 2004

Seasonal variation of major inorganic ions in the greater Seoul area was estimated using a photochemical box model and a gas/aerosol equilibrium model with emphasis on semi -volatile nitrate. Pollutant emission was determined by season by comparing the predicted concentration with the measurement one obtained for a year from the late 1996. The results showed that particulate nitrate was the highest in summer but about 40% of total nitrate was present in the gas phase. This was due to volatilization at high temperature since ammonia was sufficient to neutralize all nitrate regardless of season. As relative humidity in summer was higher than the deliquescence point, particulate ion concentration with water was two times higher than that in other season. So called ‘NOx disbenefit’ indicating increase in particulate ion concentration with decrease in NOx emission was evident especially in winter.

• 연구논문집
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• s.28
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• pp.39-47
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• 1998

Industrial electrostatic precipitation is a very complex process, which involves multiple-way interaction between the electric field, the fluid flow, and the particulate motion. This paper describes a strongly coupled calculation procedure for the rigorous computation of particle dynamics during electrostatic precipitation. The turbulent gas flow and the particle motion under electrostatic forces are calculated by using the commercial computational fluid dynamics (CFD) package FLUENT linked to a finite-volume solver for the electric field and ion charge. Particle charge is determined from both local electrical conditions and the cell residence time which the particle has experienced through its path. Particle charge density and the particle velocity are averaged in a control volume to use Lagrangian information of the particle motion in calculating the gas and electric fields. The turbulent particulate transport and the effects of particulate space charge on the electrical current flow are investigated. The calculated results for poly-dispersed particles are compared with those for mono-dispersed particles, and significant differences are demonstrated.

• Journal of ILASS-Korea
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• v.22 no.2
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• pp.87-95
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• 2017

Recently, as the interest in environmental issues have increased around the world, the regulation on vehicle exhaust have been tightened in each country. To satisfy such tightened exhaust regulation, automotive manufactures are forced to equipped Diesel Particulate Filter (DPF) at Diesel vehicles. If DPF is used for a long time, DPF regeneration should be performed. The objective of this study is to research on post injection for DPF regeneration. The result of the study was that it was desired that retarding post injection timing, lower load of engine and smaller the amount of main fuel injection, for DPF regeneration. Oil dilution was tended to increase as load was lower, amount of post injection was increased, and post injection timing was retarded.

• Journal of computational fluids engineering
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• v.12 no.4
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• pp.14-19
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• 2007

We present a direct numerical simulation technique and some preliminary results of the capillary spreading of a droplet containing particles on the solid substrate. We used the level-set method with the continuous surface stress for description of droplet spreading with interfacial tension and employed the discontinuous Galerkin method for the stabilization of the interface advection equation. The distributed Lagrangian-multipliers method has been combined for the implicit treatment of rigid particles. We investigated the droplet spreading by the capillary force and discussed effects of the presence of particles on the spreading behavior. It has been observed that a particulate drop spreads less than the pure liquid drop. The amount of spread of a particulate drop has been found smaller than that of the liquid with effectively the same viscosity as the particulate drop.

• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.29-31
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• 2013

In this study, the characteristics of particulate matters (PM) from diesel and biodiesel fuel combustion was experimentally investigated. The experiment was performed in a single cylinder common-rail compression ignition engine. The fuels were injected at -5 CAD (Crank angle degree) ATDC (After top dead center) with 80 MPa injection pressure. Size distribution of PM was measured by scanning mobility particle sizer (SMPS) and morphology of PM was studied by transmission electron microscopy (TEM). PM from biodiesel shows lower emission level and smaller primary particles.

• Journal of Environmental Science International
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• v.33 no.5
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• pp.297-304
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• 2024

PM (Particulate Matters) was collected from a bag filter dust collector at an aluminum foundries, and its physicochemical properties were investigated using particle size analyzer and scanning electron microscopy with energy dispersive X-ray spectrometer (SEM/EDS). The median volume diameter of the particles passing through the pretreatment dust collector of the cyclone was approximately 10 ㎛. The cyclone pretreatment dust collector was shown to significantly reduce the throughput of large particles with a particle size of 100 ㎛ or more. The chemical composition of the particles showed a high Al content, and trace amounts of Mg, Si, and Zn were detected.