• 한국대기환경학회지
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• 제19권3호
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• pp.297-306
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• 2003

Works were focused on back pressure characteristics of ceramic fiber filter on DPF (Diesel Particulate Filter) system and experiments were performed to select appropriate filter which can filter particulates. Filters were installed on metal -support tube which has openings for exhaust gas flow. Ceramic fiber filters with high specific surface area and adequate high temperature strength are commercially available for filtration of diesel particulates and in -situ hot regeneration. Thus, ceramic blanket and ceramic board which are used as insulating media were applied to filter and filtration apparatus was installed on exhaust gas line connected to 2.0 L diesel engine. Alternating filter structure to adapt DPF system, collection efficiency test of diesel particulates was measured. In case of ceramic blanket, pressure drop was low, caused by the destruction of soft structures. Also, particulate collection efficiency was decreased depending on loading time. In case of ceramic board, structure design was altered to reduce back pressure on DPF system. Structure design was altered to induce Z-flow by making 10 mm and 5 mm holes on the surface of media. Alteration of 5 mm hole showed that media have low back pressure but particulate collection efficiency was 77%, while 10 mm hole showed that of 90%.

• 한국지구과학회지
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• 제40권4호
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• pp.414-427
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• 2019

In East Asia, the long-range transport of dust storms originating from Mongolia and northern China affects airborne dust loadings over downwind areas in the southern Korean Peninsula. Since 1997, dust loading cases caused by dust storms have been observed using the thresholds of total suspended particles (TSP, ${\geq}250{\mu}g\;m^{-3}\;hr^{-1}$) and particulate matter less than $10{\mu}g$ ($PM_{10}$, ${\geq}190{\mu}g\;m^{-3}\;hr^{-1}$) in the central-southern Korean Peninsula. There were two dust loading cases that exceeded these thresholds in 2016 and three in 2017, which reflects the downward trend of the last twenty-one years in the central-southern Korean Peninsula. Furthermore, five other dust loading cases with mass concentrations lower than the thresholds were observed from 2016 to 2017. In the moderate dust loading cases exceeding the thresholds, a descending motion of cut-off lows below $45^{\circ}N$ and a southward trough at 500 hPa gpm isopleths intensified at the western ridge, and largely extended the surface high-pressure system over southeast China. Airborne dust loadings following pronounced north-westerlies in the forward side of the high-pressure system were transported to the surface of the central-southern Korean Peninsula. However, in slight dust loading cases lower than the thresholds, the restricted descending motion of cut-off lows over $45^{\circ}N$ and the southwestward trough at 500 hPa gpm isopleths intensified the zonal flow over the Korean Peninsula. Surface high- and low-pressure systems moved eastward from the source compared to moderate dust loading cases. Due to the zonal movement of dust storms traversing eastern China, slight dust loading cases were observed with relatively higher ratios of $PM_{2.5}/TSP$ and carbon monoxide (CO) in the central-southern Korean Peninsula.

• Journal of Pharmaceutical Investigation
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• 제26권2호
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• pp.125-135
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• 1996

Solid lipid nanoparticles(SLN) are particulate systems for parenteral drug administration and suitable for controlled release. SLN were prepared by homogenization process. Dispersion at increased temperature (molten lipid) was performed to yield SLN loaded with lipophilic drugs. Tetracaine base, lidocaine base, prednisolone, methyltestosterone and ethinylestradiol were used as model drugs to access the loading capacity and to study the release behavior. To investigate production parameters(lipids, surfactant concentration, homogenizing rpm) in the formation of SLN, particle size was performed by laser diffraction analysis. The mean particle size of SLN with stearic acid or trilaurin was below 1 micron. By decreasing the particle size and increasing the surfactant concentration, the release rate was increased especially in the case of highly lipophilic drug loaded SLN. Methyltestosterone or ethinylestradiol loaded SLN showed a distinctly prolonged release over a few days.

• 한국해양환경ㆍ에너지학회지
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• 제12권2호
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• pp.75-83
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• 2009

2003년부터 2006년 사이의 새만금 방조제 내측 표층 해역에서 입자성 부유물질(suspended particulate matter), 입자성 유기탄소(particulate organic carbon) 그리고 용존 유기탄소(dissolved organic carbon)의 분포 변화를 조사하였다. 하천을 통해 새만금 방조제 내측으로 유입되는 입자성 물질과 유기탄소는 대부분 풍수기인 여름철에 집중 되었고, 이는 2006년 4월 최종 물막이 공사 완료 후 폐쇄 환경이 된 새만금 내측 해역에 많은 양의 유기물 부하가 단기간에 집중될 수 있음을 시사하였다. 한편, 2003년 이후 제4호 방조제 완공으로 막혀진 만경강 하구역에서 새만금 방조제에 이르는 해역에서 입자성 물질과 유기탄소의 표층 농도가 증가하는 것이 관찰되었다. 특히 부영양화(eutrophication)로 인한 식물 플랑크톤의 증가로 입자성유기탄소를 비롯, 생물기원의 유기탄소가 증가하였다. 이러한 표층의 과도한 입자성 유기탄소의 증가는 향후 저층 퇴적 환경으로 침전되었을 경우 용존 산소 고갈에 큰 영향을 미칠 것으로 판단된다.

• Advances in materials Research
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• 제1권3호
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• pp.221-231
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• 2012

In this study, the physical and mechanical properties of bamboo fiber reinforced epoxy composites were studied. Composites were fabricated using short bamboo fiber at four different fiber loading (0 wt%, 15 wt%, 30 wt% and 45 wt%). It has been observed that few properties increases significantly with respect to fiber loading, however properties like void fraction increases from 1.71% to 5.69% with the increase in fiber loading. Hence, in order to reduce the void fraction, improve hardness and other mechanical properties silicon carbide (SiC) filler is added in bamboo fiber reinforced epoxy composites at four different weight percentages (0 wt%, 5 wt%, 10 wt% and 15 wt%) by keeping fiber loading constant (45 wt%). The significant improvement of hardness (from 46 to 57 Hv) at 15 wt%SiC, tensile strength (from 10.48 to 13.44 MPa) at 10 wt% SiC, flexural strength (from 19.93 to 29.53 MPa) at 5 wt%SiC and reduction of void fraction (from 5.69 to 3.91%) at 5 wt%SiC is observed. The results of this study indicate that using particulate filled bamboo fiber reinforced epoxy composites could successfully develop a composite material in terms of high strength and rigidity for light weight applications compared to conventional bamboo composites. Finally, SEM studies were carried out to evaluate fibre/matrix interactions.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.132-132
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• 2006

Filler loading (fiber or particulate) usually increases the melt viscosity of polymers. In contrast, the addition of these fillers and fibrillation of thermotropic liquid crystalline polymer (LCP) jointly decreased the viscosity of polymer melts to lower than those of pure component polymers, filler-loaded or LCP-blended ones; and even decreased the viscosity with increasing filler loading. Termed as rheological hybrid effect, this phenomenon correlated well with the LCP fibrillation in these ternary systems. Research taking fillers of various shapes and sizes showed that the filler addition promoted the LCP fibrillation, depending upon thermodynamic and dynamic factors involved.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.147-152
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• 2002

The mechanism of the aerosol(mist) generation generally consists of spin-off, splash, and evaporation/condensation. Host researchers showed some theoretical model for predicting the particulate size and generation rate without real cutting in turning operation. These models were based on the spin-off mechanism, and verified good for modeling the process. However, in real machining, the cutting tool destroys the flow direction of the cutting fluid and generate the heat by the relative motion of between tool and workpicee, and so the mass loading of the mist is greatly increased as compared with non-cutting. In this paper, we show some experimental data that the mist formation characteristics of cutting is different from that of non-cutting.

• 한국물환경학회지
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• 제27권3호
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• pp.306-313
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• 2011

In this paper, runoff characteristics of South-Han river watershed in terms of refractory organic matters were investigated. The concentrations of DOC, POC, R-DOC, R-POC in runoff and flow rates were determined by monitoring 27 times in dry season and 4 times in rainy season. The concentrations of the dissolved refractory organic matter, R-DOC was the lowest in fall and similar in the other dry seasons. The particulate refractory organic matter, R-POC showed less fluctuation than R-DOC. In summer, mass loading was the highest than other dry seasons. The concentrations of R-DOC, R-POC were showed to be affected by runoff volume. The mass loading grows higher as runoff volume gets higher.

• 공업화학
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• 제32권6호
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• pp.695-699
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• 2021

본 연구에서는, 노후된 엔진을 사용하는 트럭 및 특수차량에서 배출되는 NO_x 및 PM을 동시에 제거하기 위해 SDPF 후처리 시스템 연구를 수행하였다. 우선, SDPF의 SCR 촉매를 선정하기 위해서, V/TiO₂와 Cu-zeolite 촉매의 de-NO_x 성능을 비교하였으며, SCR 촉매특성분석은 BET, XRD 및 NH₃-TPD를 통해 분석하였다. 촉매 활성시험 결과, Cu-zeolite 촉매가 가장 우수한 내열성을 보여주었다. 최적의 SDPF 코팅을 위해서, 목표로 설정된 입자 크기에 맞추어 슬러리를 제조하였다. SCR 코팅량에 따른 SDPF의 코팅안정성과 배압 결과, SDPF 촉매를 로딩량별로 A, B, C 샘플을 제작하여 코팅안정성과 배압 및 de-NOx 성능을 비교한 결과 B 샘플에서에서 가장 우수한 결과를 보였다. 최적 SDPF 후처리시스템에 대해 엔진동력계 시험을 실시하였으며, 시험결과 Eu-5 규제를 만족하였다.

• 한국응용과학기술학회지
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• 제29권4호
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• pp.561-569
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• 2012

본 연구는 강원도 소재 동해항만에서 발생하는 미세먼지 관리를 위한 환경비용편익을 산출하는 것이다. 항구 인근에 부유하는 미세먼지의 농도는 매우 높은 편이며, 지점에 따라 국가 기준인 $100{\mu}g/m^3$ 이상으로 관측되는 곳도 있다. 시험대상 항구는 주로 석회석과 석탄을 취급함으로써 미세입자상 물질이 하역시 다량 발생한다. 연구결과 PM10을 기준으로 년간 12톤의 미세먼지가 하역작업 시 발생하는 것으로 밝혀졌다. 덧붙여서 원료물질을 비롯한 다양한 화물을 운송하는 대형차량 및 중장비는 디젤 검댕이를 발생하고, 도로먼지의 비산을 유발한다. 지방정부는 해마다 20억원 이상의 비용을 투자하여 대기중 미세먼지를 제거하고 있다. 편익대비 비용을 산출한 결과 그 효과는 최소 240%에서 최대 720%까지 얻을 수 있는 것으로 나타났다.