• 한국지반공학회논문집
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• 제29권11호
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• pp.17-27
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• 2013

본 연구의 목적은 쇄석배수층에 설치된 토목섬유의 효율성을 실험을 통해 검증하고자 하였다. 지지력 보강 역할을 수행하는 PET매트는 재하실험을 수행하여 효율성을 검증하였다. 또한, 폐색 방지 역할을 수행하는 PP매트는 하중재하와 강우 침투, 성토재의 특성에 따른 폐색 조건을 찾고 폐색에 의한 통수능 변화량를 파악하였다. PET매트의 재하실험 결과, PET매트가 설치되지 않으면 쇄석이 점토지반에 관입되며 파괴되었으며, PET매트 설치시 연약지반의 보강효과가 큰 것을 알 수 있었다. 또한, PP매트가 없는 경우에는 성토재의 점착력이 작으면 쇄석배수층이 쉽게 폐색되며, 이로 인해 쇄석배수층의 통수능이 약 98%정도 감소되었다.

• 농업과학연구
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• 제40권3호
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• pp.253-260
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• 2013

In this study, laboratory model test carried out to present the suitable range of particle size distribution and clogging behavior of recycled aggregates and crushed stone as horizontal drains in soft ground. The recycled aggregates and crushed stone showed clogging phenomenon because the top fill material and bottom clay inflow into the horizontal drains. The pp mat was the most effective method to minimize clogging phenomenon. The horizontal coefficient of permeability in case of installing the pp mat showed largely 2.1 times more than the case of not installing. When the pp mat is not installing, the thickness of fine grained soil inflow into the horizontal drains showed 6.7~13.3% range in top fill material and 3.3~6.7% range in bottom clay. Overall, the reduction of the discharge capacity by fine grained soil inflow showed small in recycled aggregates and crushed stone. Also, the appropriate criterion range of particle size distribution is presented to make use of a horizontal drains in soft ground on the basis of laboratory test.

• Carbon letters
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• 제15권3호
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• pp.203-209
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• 2014

The adsorption of volatile organic compounds (VOCs) was carried out using an activated carbon fiber (ACF) filter in an automobile. The adsorption capacities of formaldehyde, toluene, and benzene on an ACF filter were far better than those of a polypropylene (PP) mat filter and combined (PP+activated carbon) mat filter by batch adsorption in a gas bag. In a continuous flow of air containing toluene vapor through an ACF packed bed, the breakpoint time was very long, the length of the unused bed was short, and sharp "S" -type breakthrough curve was plotted soon after breakpoint, showing a narrow mass transfer zone of toluene on the ACF. The adsorption amount of toluene on the ACF filter was proportional to the specific surface area of the ACF; however, the development of mesopores 2-5 nm in size on the ACF was very effective with regard to the adsorption of toluene. The ACF air clarifier filter is strongly recommended to remove VOCs in newly produced automobiles.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2009년도 춘계학술발표논문집
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• pp.212-215
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• 2009

요구되는 접착력과 그라프트율을 만족시킬 수 있는 변성폴리프로필렌의 제조 기술 확립을 목표로 변성폴리프로필렌의 최적 합성을 위한 과산화물, 변성폴리프로필렌의 최적 합성을 위한 촉매 및 반응몰비, 변성폴리프로필렌의 최적 합성을 위한 반응온도, 반응시간 확립을 통한 변성 PP 제조기술을 개발하였으며, $90{\Phi}$ extruder에서 상업 생산을 위한 공정 제어 기술 확립과 접착력과 그라프트율 등을 나타내는 변성폴리프로필렌의 최적 합성 조건 확립을 통한 폴리프로필렌 엘라스토머 복합수지용은 물론 강관 코팅용, 시트 및 필름용 등의 변성 폴리프로필렌 제조기술을 개발하였다. 이들 변성 PP를 활용하여 매트릭스 및 필러, 분산 조건 변경 시험, 엘라스토머 폴리프로필렌 컴파운드 최적 분산 조건 확립, 엘라스토머 폴리프로필렌 컴파운드 pilot 생산 및 제품 분석을 통하여 초고강성 범퍼, 룸미러 케이스 소재, 인패널, 도어용으로 사용될 수 있는 자동차 부품용 폴리프로필렌 복합수지 개발을 완료하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.186-191
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• 2004

we can say that the increasing range of the value of GMT Sheet's tensile strength in the direction of fiber orientation is getting wider as the fiber content increases. It shows that the value of GMT Sheet's tensile strength in the direction of fiber orientation 90 is similar with the value of pp's intensity when fiber orientation function is J= 0.7, regardless of the fiber content. Tensile strength of GMT Sheet is affected by the fiber orientation distribution more than by the fiber content.

• Nuclear Engineering and Technology
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• 제50권3호
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• pp.488-493
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• 2018

The Firebrick Resistance-Heated Energy Storage (FIRES) concept developed by the Massachusetts Institute of Technology aims to enhance profitability of the nuclear power industry in the next decades. Studies carried out at Massachusetts Institute of Technology already provide estimates of the potential revenue from FIRES system when it is applied to industrial heat supply, the likely first application. Here, we investigate the possibility of operating a power plant (PP) with a fluoride-salt-cooled high-temperature reactor and a closed Brayton cycle. This variant offers features such as enhanced nuclear safety as well as flexibility in design of the PP but also radically changes the way of operating the PP. This exploratory study provides estimates of the revenue generated by FIRES in addition to the nominal revenue of the stand-alone fluoride-salt-cooled high-temperature reactor, which are useful for defining an initial design. The electricity price data is based on the day-ahead markets of Germany/Austria and the United States (Iowa). The proposed method derives from the equation of revenue introduced in this study and involves simple computations using MatLab to compute the estimates. Results show variable economic potential depending on the host grid but stress a high profitability in both regions.

• Composites Research
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• 제20권1호
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• pp.23-31
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• 2007

Jute fiber Green Composite의 기계적 향상을 위한 계면특성을 향상시키기 위하여 커플링제를 도입하여 첨가량에 따른 특성변화를 실험적으로 규명하였다. Maleic anhydride grafted popolypropylene(MAPP)는 자연섬유와의 계면특성의 향상에서 물리화학적 역할을 하는 것으로 판단된다. MAPP에 의한 용융상태에서의 낮아진 수지의 점도는 흐름성이 향상되어 섬유의 계면과의 접촉 면적을 확대시킨다. 약 80mm의 jute 장섬유 mat에 maleated coupler가 혼합된 PP 복합재의 물성 향상과 열가소성수지의 물리적 변화와의 관계를 고찰하였다. 이 물리적 현상을 유동지수(MI: Melting flow index) 및 점도, contact angle, 복합재료 두께, 계면전단강도, morphology 분석 등의 인자들을 이용하여 기계적 물성 향상에 기여하는 정도를 확인하였다. 특히 유동지수(MI)와 점도, MAPP의 혼합량은, 전당강도(IFSS), 인장 및 굴곡 강도와 인장탄성률의 향상과 매우 관계가 있음을 실험 결과를 통하여 확인하였다.

• 한국해양환경ㆍ에너지학회지
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• 제17권1호
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• pp.42-45
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• 2014

폐 FRP의 처리는 매우 급박하나 뚜렷한 생산성 있는 방법이 많지 않다. 본 연구진은 FRP의 층간 구성에 초점을 맞춰 층으로 분리하였으며, 각 층의 구성 성분에 따라 물성이 다름을 확인한 바 있다. 그 중 유리섬유 다발이 바구니 조직으로 틀을 이루고 있는 로빙층에서 유리섬유("F섬유")를 제작하였다. 그 크기를 폭 1 mm와 3 mm로 달리하고 길이는 3 cm로 잘라 부피비로 0.5%, 0.7%, 1.0%, 1.5%를 포함하도록 섬유강화 콘크리트(fiber reinforced concrete, FRC)를 제작하였다. 압축강도, 인장강도, 휨강도를 비교하기 위해 강화재를 포함하지 않은 것과 합성수지(polypropylene, PP)를 0.1% 포함하는 비교 샘플도 제작하였다. 실험결과 인장강도와 휨강도는 PP를 포함하는 것과 유사하거나 버금가는 강도를 보인 반면, 압축강도는 강화재를 넣지 않은 것과 유사하거나(3 mm 폭), 약 20% 정도 감소하였다(1 mm 폭). 이 결과를 바탕으로 폐 FRP 소재를 건축자재로 쓸 경우에는 압축강도가 큰 영향을 주지 않는 부분에 사용할 것을 권한다.

• Membrane and Water Treatment
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• 제4권2호
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• pp.143-155
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• 2013

Four membranes were used to separate Chlorella sp. from their culture medium in cross-flow microfiltration (MF) experiments: cellulose acetate (CA), cellulose nitrate (CN), polypropylene (PP) and polyvinylidenefluoride (PVDF). It was found that the hydrophilic CA and CN membranes with a pore size of 1.2 ${\mu}m$ exhibited the best performances among all the membranes in terms of permeation flux. The hydrophobicity of each membrane material was determined by measuring the angle between the water (liquid) and membrane (solid). Contact angle measurements showed that deionized (DI) water had almost adsorbed onto the surfaces of the CA and CN membranes, which gave $0.00^{\circ}$ contact angle values. The PP and PVDF membranes were more hydrophobic, giving contact angle values of $95.97^{\circ}$ and $126.63^{\circ}$, respectively. Although the pure water flux increased with increasing pore diameter (0.8 < 1.2 < 3.0 ${\mu}m$) in hydrophilic CA and CN membranes, the best performance in term of filtration rate for filtering a microalgae suspension was attained by membranes with a pore size of 1.2 ${\mu}m$. The fouled membrane pore sizes and pore blocking were inspected using a scanning electron microscope (SEM). MF with large pore diameters was more sensitive to fouling that contributed to intermediate blocking, where the size of the membrane pores is almost equivalent to that of cells.

• 한국자원식물학회지
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• 제25권6호
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• pp.753-761
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• 2012

We performed phylogenetic analyses of a total of 21 acessions covering 5 species in the Korean Trigonotis and one outgroup species using nuclear ribosomal ITS and chloroplast rbcL, matK, ndhF sequences. Outgroup were chosen from the closely related genus Lithospermum zollingeri. Both parsimony and Bayesian Inference methods were used to reconstruct the evolutionary history of the group. The evidence collected indicated that phylogenetic relationships among Korean Trigonotis species are unresolved based on nuclear marker (ITS), as the same as based on separated chloroplast sequences. While the phylogenetic relationships of Korean Trigonotis species almost clearly were resolved in combined chloroplast sequences. Thus, the members of Trigonotis coreana can be distinguished to the members of Trigonotis peduncularis in combined cpDNA sequences and Trigonotis nakaii was treated as a synonymed to Trigonotis radicans var. sericea. In addition, the MP and BI analysis showed Trigonotis icumae as sister of the remained Korean Trigonotis species based on combined molecular markers (BI: PP = 1).