• 한국입자에어로졸학회지
• /
• 제12권1호
• /
• pp.11-20
• /
• 2016

A large amount of wear dust generated during train operation is a major dust source in urban railway tunnels. To check possibility of a louver dust collector for the removal of dust in the railway tunnel, five louver dust collector models were designed and their performance was tested in a wind tunnel. JIS Z 8901 Class 8 dust was used as a test dust. Pressure drop and particle collection efficiency were evaluated with the face velocity ranging from 1 m/s to 4 m/s. At this low velocity range, particle collection efficiency of the louver dust collector was found to be insensitive to air velocity and design parameters. Pressure drop was under 40 Pa, and $PM_{10}$ and $PM_{2.5}$ collection efficiencies were approximately 50% and 30%, respectively.

• 한국가시화정보학회지
• /
• 제19권3호
• /
• pp.39-45
• /
• 2021

An experiment to visualize fine dust captured by FOG droplet is conducted. Coal dust with 23.56 MMD (Mean Median Diameter) and water with 17.02 MMD is used as fine dust and FOG droplet. Long distance microscope and high-speed camera are used to capture the images of micro-scale particles sprinkled by acrylic duct. After measuring and comparing the size of the coal dust and FOG droplet to MMD, process to seize the coal dust with FOG droplet is recorded in 2 conditions: Fixed and Floated coal dust in the floated FOG droplet flow. In both conditions, a coal dust particle is collided and captured by a FOG droplet particle. A FOG droplet particle attached at the surface of the coal dust particle does not break and remains spherical shape due to surface tension. Combined particles are rotated by momentum of the particle and fallen.

• 한국전자통신학회논문지
• /
• 제17권6호
• /
• pp.1237-1242
• /
• 2022

대기오염물질인 미세먼지의 50% 이상을 차지하고 있는 비산먼지는 건설공사가 주요 배출원(29.5%)으로 이에 대한 관리를 위하여 비산먼지 억제를 위한 시설 설치 및 조치에 관한 기준을 법으로 제시하고 있다. 그러나 소규모 건설현장은 관리 대상기준이 아니며 건설현장에서 발생하는 비산먼지를 개량적으로 측정하여 조치하는 항목이 미흡하다. 본 논문에서는 비산먼지를 더욱 쉽게 측정하고 모니터링하기 위하여 먼지의 혼탁도를 측정하는 광학기법을 사용한 방법을 설계하고 구현하였다. 먼저 광학기법을 이용한 비산먼지의 혼탁도를 측정하는 방법을 제시하고 비산먼지측정 시스템을 구현하여 건설현장에서 발생하는 실제 비산먼지의 혼탁도를 측정하였다.

• Journal of Astronomy and Space Sciences
• /
• 제8권1호
• /
• pp.1-10
• /
• 1991

The dust formation processes in novae are investigated with close attention to recent infrared observations. Using mainly the classical nucleation theory, we have calculated the time scales of dust formation and growth in the environments of novas. Those time scales roughly the typical observations. We have classified the dust-forming novae into three classes according to their explosion properties and the thermodynamic properties of dust grains. Oxygen grains form much later than carbon grains because of their thermodynamic properties. The effect of grain formation to the efficiency of stellar winds to drive the material outward is tested with newly obtained Planck mean values of dust grains.

• 천문학회지
• /
• 제20권1호
• /
• pp.1-26
• /
• 1987

By inverting the brightness integral for the dust-scattered continuum, we have determined how the dust grains are distributed inside the Orion nebula. The scattering characteristics of the Orion dust at a given wavelength is kept constant within the nebula, and the geometry of the nebula is assumed to have a hemispherical shape. The resulting radial distance dependence of the distribution of dust number density, $N_d(r)$, shows that the dust grains are depleted at the central region of the Orion nebula and concentrated in the region $5'{\sim}6'$ away from the Trapezium stars. The scattering characteristics of the Orion dust are of moderately forward throwing nature, and the Orion dust has low values of albedo.

• Journal of Astronomy and Space Sciences
• /
• 제25권4호
• /
• pp.329-334
• /
• 2008

We investigate the spectral energy distributions (SEDs) of Massive Young Stellar Objects (MYSOs) using the various infrared observational data including the Infrared Space Observatory (ISO) data. We model the dust envelopes around the stars using a radiative transfer model for spherically symmetric geometry. Comparing the model results with the observed SEDs of the two MYSOs (AFGL 4176 and AFGL 2591), we derive the relevant dust shell parameters including the dust opacity, the dust density distribution, and dust temperature distribution. We find that the spherical model can produce the SEDs roughly similar to the observations. We expect that the results would be helpful for making more realistic non-spherical dust envelope models for MYSOs.

• 천문학회보
• /
• 제41권2호
• /
• pp.51.1-51.1
• /
• 2016

We revisited a recent dust emission observed at a main-belt asteroid P/2010 A2 in terms of dynamical properties of dust particles and large fragments. This is a continued research that we made a presentation at the Korean Astronomical Society 2016 Spring Meeting, but we have strengthened the dynamical analysis of the ejecta to afford the conclusive evidence for the enigmatic phenomenon. We thus constructed a model to reproduce the morphology of the dust cloud based on the dust dynamics, and succeeded in reproducing the observed morphologies in different epochs over several years. For further analysis, we reconstructed the proper motion of large fragments with respect to the dust emission source estimated from our dust model. We found that (i) the dust cloud morphologies and (ii) observed trajectories of fragments are reasonably explained only when we assumed that both were ejected from a position where no object was detected from any observations. This result suggests that the original body was shattered by an impact, leaving only debris into space. In this presentation, we will compare our results with impact laboratory studies and provide an impact interpretation of the P/2010 A2 activity.

• 한국대기환경학회지
• /
• 제20권6호
• /
• pp.739-748
• /
• 2004

A hybrid dust-collector combining a fabric filter with centrifugal force was developed to enhance the performance of the conventional fabric filter systems and its performances were evaluated to compare to that of the existing dust collector. The pressure drop rapidly increased with increasing the elapsed time and the face velocity in two filtration systems. But the increasing ratio of a hybrid dust-collector compare to the existing dust collector was lower. This results were confirmed from the performance such as cleaning interval, residual pressure drop and dust loading rate. The overall collection efficiency of the hybrid dust-collector was more than 99.6% and this showed a improvement of 0.6～2% than that of the existing dust collector. Especially, the fractional collection efficiency at the particle size of around 1${\mu}{\textrm}{m}$ is about 4% higher than that of the existing dust collector.

• 한국산업융합학회 논문집
• /
• 제23권1호
• /
• pp.101-106
• /
• 2020

Along with dust collection efficiency, pressure loss is a very important cyclone operation factor. A severe rise in pressure loss causes the problem of cost. To solve the problem, the method connecting axial-vane type cyclones in parallel is suggested recently. The axial vane type cyclone dust collector applied in this study is a small portable type. Multiple cyclones are installed in a round type. The basic performance test on the axial vane type cyclone dust collector was conducted. As a result, the cut size reduced along with a rise in the wind velocity of the cyclone dust collector inlet. According to the test on dust collection efficiency, the effect of dust collection began to appear in the range of 3㎛ and dust collection efficiency was greatly improved at 5 ㎛. The noise of the cyclone dust collector well met the fan sound power level of KSB 6361.

• 천문학회보
• /
• 제36권2호
• /
• pp.71.1-71.1
• /
• 2011

Significant discrepancies have been found between the dust masses of edge-on spiral galaxies derived from various tracers (optical/near-infrared, far-infrared/sub-millimeter observations, and the variation of dust attenuation with viewing angle). Here we report the first detection of a vertically extended far-ultraviolet (FUV) and near-UV (NUV) emission in an edge-on spiral galaxy NGC 891. The vertically extended emission is interpreted as the dust-scattered light due to a extraplanar dust layer in NGC 891 that contains about the same mass as the standard thin dust disk. This new dust component completely encloses the stellar disk and bulge, and solves the puzzle of dust mass.