• Resources Recycling
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• v.11 no.4
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• pp.11-16
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• 2002

Analysis and separation of constituent materials of old car have been performed by using the industrial shredding line. For this aim, three old cars made by domestic automobile manufacturers, Sonata II, Sephia and Prince were chosen and delivered in pressed form without engine, tires and doors, etc. Shredding line was substantially composed of pre- and main-shredder. cyclone, magnetic separation, eddy current separation and man-power separation. From the separation of shredder products, iron scrap was observed to be the major material of old car accounting for 60.1 ％ of total weight and non-ferrous metals involving Al, Cu and Zn, etc. were about 2％. Light fluff, about 90％ of total fluff product, was comprised with plastic, fiber and sponge, etc. and the fraction of 5 cm undersize in light fluff was 70.5%. In case of heavy fluff, however. rubber and plastic were found to be the major constituent materials of it. Among the constituent materials of fluff, plastic showed the highest calorific value, more than 10,000 cal/gr and leather and rubber showed relatively high chlorine content, 10.3 and 2.55 wt%, respectively.

• Particle and aerosol research
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• v.4 no.2
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• pp.37-50
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• 2008

Concerns on centrifugal classifiers, of which have cut sizes are below few micrometers, have been increased and it is prospected to be used in extensive industries, such as manufacturing the fine minerals, cosmetics, advanced electric materials, and life science. This paper reviews the recent progress of research and development on the centrifugal classifiers. General categorization of classifiers for feeds was assessed and separation mechanism of the classifiers was followed. History of centrifugal classifiers was explored and some points to be improved were briefly indicated. Fundamental theory of the classification by centrifugal classifiers was pearly studied, and advanced and further understandings on factors affecting the separation or grading efficiency are described. Factors determining the classification precision and efficiency of centrifugal classifiers, such as geometry, rotational speed and inclined angle of rotating vanes, feed and air flow rates, and rotor dimensions are reviewed.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.3
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• pp.278-284
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• 2017

Generally, classifiers have been used as machines to crush raw materials and classify suitable particle sizes in all industrial fields, such as food, chemical, and mineral. However, the technique for classifying micron-sized particles between 5 and $20{\mu}m$ is inferior. In particular, numerous experiments and considerable experiences are required to predict the particle size, because the classifier particle size is determined according to the internal flow. However, it is quite difficult to set the driving conditions so that the desired particle size can be classified only by experience and experimentation. Therefore, this study proposes a method of predicting the average particle size by employing multiphase flow analysis and the Taguchi method; this method is subsequently verified.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.02a
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• pp.99-105
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• 2003

지방을 함유하고 있는 붉은자루 동충하초는 일반적으로 분쇄에 널리 사용되고 있는 핀밀이나 해머밀로 분쇄하기에는 어려움이 있다 핀밀이나 해머밀은 분쇄 로터날과 분쇄망사이의 갭사이에서 로터의 회전에 의하여 발생하는 원심력을 이용 충격과 마찰로 분쇄물을 분쇄망의 홀크기에 의존하여 분쇄를 하게된다. 이때 지방이 많은 분쇄물의 경우 로터와 망의 마찰로 인한 열방생으로 인하여 지방이 녹아 분쇄망의 홀을 매우는 눈막힘 현상이 발생하게 되어 분쇄를 더이상 할 수 없게 된다. (중략)

• Journal of the Korean earth science society
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• v.23 no.7
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• pp.565-574
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• 2002

Based on previous investigations of aerial photographs and topographical surveys, this study focuses on the sedimentologic features of the Daebudo area including sedimentation processes, sedimentary facies and hydrologic conditions of the erosional coast. A total of 137 surface sediments and one core (by hand auger) sediment were obtained to interpret the depositional environment of the erosional coast in the macro-tidal coast. Surface sediments are distributed from sandy gravel (sG) to silt (Z). Textural parameters are characterized not only by coarse, poorly sorted, positive skewed and multi-modal distribution in the supra-tidal flat, but also finer, relatively well-sorted, symmetric distribution in the intertidal flat. According to the C/M diagram, sediment transport modes of study area are characterized by the mixed mode of suspension and bedload in the upper-, middle-tidal flat and by uniform suspension in the lower-tidal flat due to tidal effect. Vertical sediment distribution of the core, collected near shoreline, shows coarsening-upward, poorly sorted pattern by the input of detritus resulting from coastal erosion. Considering the sedimentological features of the study area, it appears to be composed of a coastal zone changed by not only artificial reclamation, but also by natural processes such as strong wave action due to typhoons and storms during high water level and long/short-term sea level rising. As a result, tide-dominated erosional coasts show that the shore is affected by local, temporal and hydrological conditions near high tide level and that the intertidal flat is represented by a general tide-dominated sedimentary environment.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.2
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• pp.107-116
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• 1999

To study the characters of surface sediment and to describe the seasonal depositional environment as a result of sedimentation process off Byun-San Peninsula, a total 61 samples of surface sediment (32 samples in summer; 29 samples in winter) were collected and analysed. A digitized depth data from sea chart and echosounding profiles along five trans-sections were helpful for understanding the morphological factors. The types classified by the characters of surface sediment are type I (sand, S), type II (silty sand, zS), and type ill (sandy silt, sZ). Mean grain size varies from 2.11 to 7.81 ${\Phi}$. The positive-skewness shows the typical tide-dominated environment. The sediment type of the northwestern stations is medium sand and the sorting value is 0.5~1.4 ${\Phi}$ of well/moderately sorted. Meanwhile, other stations are composed of muddy sands and sandy muds transported from rivers and offshore. These sediment types toward inshore change gradually from silty sand to sandy silt. According to the C/M diagram, there are three major transport modes of sediment: bed load (Mode A), graded suspension (Mode B), and suspension (Mode C), correlating with north-eastern sandy area, middle part of silty-sand area, and southern sandy-silt area, respectively. The result of Principal Component Analysis shows also similar pattern of sediment types. In result, sediment texture of type III tends to be finer and more poorly-sorted than that of type II and sediment facies are correlateed with sedimentation process.

• Journal of Conservation Science
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• v.27 no.2
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• pp.163-179
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• 2011

This study was to identify the material characteristics and provenance of the crucibles, potteries and roof tiles from the Wonsinheungdong site in Daejeon, Korea. Similar mineral composition of each samples showed by microscopic observation and X-ray diffraction analysis. However, wall thickness and mineral characterization of each ceramic artifacts are quite different. The pottery is characterized by thin wall with 0.5 to 0.7 cm and fine grained clay matrix. While the crucible and roof tile has thick wall with 1.3 to 2.5 cm, poorly sorted texture of many quarz, orthoclase and plagioclase whithin ceramic fabric. And large elonagated voids formed by hydrocarbone of straw during the firing and loose matrix obseved in crucible. All ceramic samples and ground soil of the site show similar mineralogical characteristics geochemical behavior and clay-mineralization degree. This indicates making that the soil is probable to be a raw material of all ceramic from the Wonsinheungdong site. Also, firing temperature of most ceramic artifacts are estimated as 850 of all ceramic from the Wonsinheungdong site. Also, firing temperature of most ceramic artifacts are estimated as 850 to $950^{\circ}C$ but hardest pottery fired high temperature between 1,050 to $1,150^{\circ}C$. The vitreous molten materials interpreted in slag included segregation of copper and tin. But it can not exclude the possibility that the glass molten material because observed reddish and greenish vitreous fine structure under microscopic.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.922-926
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• 2004

1970년대부터 시작된 산업화와 도시화는 국토 전반에 걸쳐서 개발을 촉진시켰으며, 그 결과로 나타나기 시작한 홍수재해와 용수부족은 보다 많은 저수시설을 요구하게 되었다. 즉, 홍수유출을 저감시키기 위해서 유역의 저류기능을 강화시킬 수 있는 댐 건설은 이수적인 측면에서 안정적인 용수공급을 보장해주는 수단으로 겸용되어 왔으며, 특히 다목적댐이 건설되면서 하도의 첨두홍수유출량을 줄이는데 크게 기여해 왔다. 댐에 의해 홍수가 사실상 사라진 댐 하류에서는 유사이송이 줄어들면서 주수로는 좁아지며, 낮아진다. 홍수가 없어진 주변 홍수터에는 식생이 활착하여 그 폭이 점차 커지고 하상은 높아진다. 과거 댐 건설 전까지 불안정했던 작은 독려 사주에도 홍수가 없어지면서 식생이 뿌리를 내리게 되고 이로 인하여 식생에 의한 난류변화와 와류의 형성으로 주변에 유사의 퇴적이 증가하게 된다. 결과적으로 식생이 활착할 수 있는 면적이 확장되면서 사주는 점차 넓어진다. 특히, 홍수터나 사주의 외딴 관목 식생에 의한 주변 하상의 세굴, 미립토사의 퇴적, 하상재료의 분급효과는 생태 서식 측면에서 귀중한 휴식처나 피난처를 제공하게 된다. 따라서 본 연구에서는 하도의 상류에 댐이 건설되고 난 후에 댐하류의 하도에서 발생하고 있는 식생 메카니즘과 이로 인한 조도증가와 유속저하 및 홍수소통능력의 저감현상을 규명하였다.

• Journal of the Korean earth science society
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• v.28 no.7
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• pp.914-924
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• 2007

This study is to compare differences in the depositional environments of natural beaches with those of beaches developed with artificial structures in the East Coast of Korea. Naksan-Osan beaches were selected for the examination of natural beaches and Anmok-Yumjun beaches for that of developed beaches. The study was performed on the foreshores and backshores of the selected beaches, and was based on the field research during the flood period of year 2004 and the dry period of year 2005. In Naksan-Osan beaches, pain size is fuel and sorting is better from northern coast to southern coast. Furthermore, sediment undergoes changes regularly and seasonal variations are small. But in Anmok-Yumjun beaches, grain size is coarser and sorting is worse than in Naksan-Osan beaches, showing irregular tendencies. The characteristic features of the two beaches would be effected by longshore currents which change along the type of coast line and have an effect on sediment. Especially, long shore currents interrupted by artificial structures in Anmok-Yumjun beaches may cause sedimental environment changes. In Anmok-Yumjun beaches, harbor expansions will be continued, and thus more changes are expected to occur in the beaches.

• Economic and Environmental Geology
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• v.39 no.6 s.181
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• pp.719-738
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• 2006

Simrad EM950 multibeam data and surficial sediment grab samples were acquired to correlate backscatter strength with surficial sediment properties in the eastern Yellow Sea which tidal sand ridges are dominantly developed. The study area is divided into the western sand ridge zone characterized by well sorted, fine sandy sediment, and the eastern non-sand ridge zone characterized by poorly sorted, medium sand with some gravels and shell fragments. In spite of minor difference in grain size between two zones, the variations of backscatter strength between two zones are distinct. Multibeam backscatter strength of study area shows good correlation with the grain size of surface sediment as well as the carbonate contents. High occurrence of carbonate shell fragments can increase grain size and bottom roughness. The dominance of higher backscatter strength in the eastern non-sand ridge zone may reflect the effects of coarse grain size and high shell fragments contents.