• Membrane and Water Treatment
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• 제9권6호
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• pp.463-471
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• 2018

The present paper deals with the liquid-liquid extraction and flat sheet supported liquid membrane studies of Pd(II) separation from nitric acid medium using a novel synthesized ligand, namely, N,N,N',N'-tetraethyl-2,2-thiodiethanthiodiglycolamide (TETEDGA). The effect of various diluents and stripping reagents on the extraction of Pd(II) was studied. The liquid-liquid extraction studies showed complete extraction of Pd(II) in ~ 5 min. The influence of nitric acid and TETEDGA concentration on the distribution of Pd(II) has been investigated. The increase in nitric acid concentration resulted in increase in extraction of Pd(II). Stoichiometry of the extracted species was found to be $Pd(NO_3)_2{\cdot}TETEDGA$ by slope analysis method. Extraction studies with SSCD solution showed negligible uptake of Pt, Cr, Ni, and Fe, thus showing very high selectivity and extractability of TETEDGA for Pd(II). The flat sheet supported liquid membrane studies showed quantitative transport of Pd(II), ~99%, from the feed ($3M\;HNO_3$) to the strippant (0.02 M thiourea diluted in $0.4M\;HNO_3$) using 0.01 M TETEDGA as a carrier diluted in n-dodecane. Extraction time was ~160 min. Parameters such as feed acidity, TETEDGA concentration in membrane phase, membrane porosity etc. were optimized to achieve maximum transport rate. Permeability coefficient value of $2.66{\times}10^{-3}cm/s$ was observed using TETEDGA (0.01 M) as carrier, at 3 M, $HNO_3$ feed acidity across $0.2{\mu}m$ PTFE as membrane. The membrane was found to be stable over five runs of the operation.

• 공업화학
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• 제10권7호
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• pp.1066-1072
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• 1999

고기능성 건설재료로 활용하기 위하여 불포화폴리에스테르수지를 사용한 폴리머 콘크리트의 물성에 대하여 조사하였다. 탄산칼슘(충전제)의 첨가량(5~20 wt %)과 세골재의 첨가량(10~50 wt %)에 따라 다양한 배합의 공시체를 제작하여 압축 및 휨강도, 흡수시험, 내열수성시험, 내산성시험, 세공분포측정 및 SEM에 의한 미세조직 관찰등을 실시하였다. 그 결과 폴리머 콘크리트의 압축강도와 휨강도는 시멘트 콘크리트보다 4배 정도 향상되었고, 흡수율은 1/100로 감소되었으며, 내산성시험에 의한 중량감소율은 1/27로 현저히 감소되었다. 내열수성시험후에 측정한 폴리머 콘크리트의 압축 및 휨강도는 모두 내열수성시험전에 측정한 강도에 비하여 67%, 47%로 각각 감소되었으며 폴리머결합재의 분해에 의하여 세공량과 세공율은 크게 증가되었다.

• 한국세라믹학회지
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• 제35권9호
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• pp.939-944
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• 1998

실리콘함유 고분자(Polysiloxane)의 세라믹변환과정에서의 부피수축효과를 조절하기 위하여 활성화금속으로 중석을 첨가하여 열분해 및 합성반응을 통해 신 세라믹 복합체를 개발하고 이의 세라믹화 과정이나 물성을 조사하였다. 제조된 시편의 미세조직은 고분자로부터 야기된 $S_{1}$-O-C게열의 Glass기지상과, 분해잔여물(고상,기상)등과 활성화금속과의 반응르로 생성된 고경도의 탄호물로 이루어져 있어 향후 내마모재료로서의 응용을 기대할 수 있을 것이다. 제조된 복합체의 물성은 반응조건에 많이 의존함을 알 수 있었다. 1400~$1500^{\circ}C$에서 열분해 시켜 제조한 복합체의 밀도는 95% 이상의 상대밀도와, 경도 값은 7~8GPa 정도이고 탄성률은 220~230 GPa, 파괴인성응ㄴ 6~6.8$MPam^{1/2}$, 파괴강도는 380~470 MPs정도의 값을 나타내었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.790-799
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• 2010

The Upper Devonian Grossmont Formation in Alberta, Canada reserves an estimated 50 billion cubic meters of bitumen and possess about 1/6 of the total bitumen resources in northern Alberta. However, unlike the overlying Athabasca oil sands, non conventional bitumen resources has not been developed as yet. The carbonate rocks of Grosmont Formation have been subject to various stages of diagenesis, including dolomatization and karstification with a strong effect on the distribution of porosity and permeability, which resulted in highly heterogeneous reservoirs. An extensive fracture logging and mapping was performed on total of six boreholes located in the study area to explore the characteristics of fracture geometry system and the subsurface structures of carbonates reservoir that holds bitumen. Fractal dimension was used as a measure of the statistical homogeneity of the fractured rock masses. The applicability of random Cantor dust, Dc, as a fractal parameter was examined systematically. The statistical homogeneity of fractured carbonates rock masses was investigated in the study area. The structural domains of the rock masses were delineated depthwise according to estimated Dc. The major fracture orientation was dominated by horizontal beddings having dip of $0-20^{\circ}$. Also, fractures having high dip angles existed with relatively low frequency. Three dimensional fracture network modeling for each structural domain has been performed based on fracture orientation and intensity, and some representative conceptual models for carbonates reservoir in the study area has been proposed. The developed subsurface conceptual models will be used to capture the geomechanical characteristics of the carbonates reservoir.

• 펄프종이기술
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• 제38권2호
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• pp.61-71
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• 2006

Environment-friendly shock-absorbing (cushioning) materials were made using a vacuum forming method from waste wood collected from local mountains in Korea. The waste wood was pulped by thermomechanical pulping. The TMP cushions showed superior shock-absorbing properties with lower elastic moduli compared to EPS(Expanded Polystyrene) and pulp mold. Even though the TMP cushions made using at different suction times had many free voids in their inner fiber structures, their apparent densities were a little higher than EPS and much lower than pulp mold. The addition of cationic starch improved elastic modulus of the TMP cushions without increasing the apparent density, which was different from surface sizing with starch. The porosity of the TMP cushions was a little greater than EPS and much less than pulp mold. Finally, the TMP cushions have great potential to endure external impacts occurring during goods distribution.

• Ocean and Polar Research
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• 제32권2호
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• pp.145-156
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• 2010

This study investigated organic carbon fluxes in Ulleung Basin sediments, East Sea based on a chamber experiment and geochemical analyses. At depths greater than 2,000 m, Ulleung Basin sediments have high organic carbon contents (over 2.0%). Apparent sedimentation rates (ASR) calculated from excess $^{210}Pb$ activity distribution, varied from 0.036 to $0.047\;cm\;yr^{-1}$. The mass accumulation rates (MAR) calculated from porosity, grain density (GD), and ASR, ranged from 131 to $184\;g\;m^{-2}\;yr^{-1}$. These results were in agreement with sediment trap results obtained at a water depth of 2100 m. Input fluxes of organic carbon varied from 7.89 to $11.08\;gC\;m^{-2}\;yr^{-1}$ at the basin sediments, with an average of $9.56\;gC\;m^{-2}\;yr^{-1}$. Below a sediment depth of 15cm, burial fluxes of organic carbon ranged from 2.02 to $3.10\;gC\;m^{-2}\;yr^{-1}$. Within the basin sediments, regenerated fluxes of organic carbon estimated with oxygen consumption rate, varied from 6.22 to $6.90\;gC\;m^{-2}\;yr^{-1}$. However, the regenerated fluxes of organic carbon calculated by subtracting burial flux from input flux, varied from 5.87 to $7.98\;gC\;m^{-2}\;yr^{-1}$. Respectively, the proportions of the input flux, regenerated flux, and burial flux to the primary production ($233.6\;gC\;m^{-2}\;yr^{-1}$) in the Ulleung Basin were about 4.1%, 3.0%, and 1.1%. These proportions were extraordinarily higher than the average of world open ocean. Based upon these results, the Ulleung Basin might play an integral role in the deposition and removal of organic carbon.

• 폴리머
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• 제25권6호
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• pp.774-781
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• 2001

폐타이어와 폐석분 재활용을 위하여, 불포화 폴리에스터 수지에 폐석분과 폐타이어 분말의 충전량을 변화시켜 폐타이어-폐석분/폴리에스터 혼성 복합재료를 제조하였다. 매트릭스 내에서 충전제의 계면결합력과 분산력을 향상시키기 위하여 실란 커플링제[${\gamma}$-methacryloxy propyl trimethoxy silane(${\gamma}$-MPS)]를 사용하여 표면처리하고 복합재를 제조한 후 구조와 물성을 확인하였다. 실란 커플링제로 충전제를 표면처리한 경우 초기 열분해온도가 상승하고 중량감소율이 감소하였다. 커플링제로 표면처리된 경우 높은 기계적 물성을 얻었으며, 실란 농도 2 wt%에서 매트릭스 및 WTC의 함량에 관계없이 최대값을 나타내었다. 유기 충전제 증가에 따라 복합재의 기공도는 증가하나 표면처리에 의해 감소시킬 수 있으며 유기 충전제의 함량에 따라 기공 크기분포도 변화한다.

• 대한지리학회지
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• 제45권3호
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• pp.342-359
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• 2010

반구대 암각화는 울산광역시 울주군 언양읍 대곡리 반구동에 위치하며, 1995년 국보 제285호로 지정되었다. 1965년 사연댐 건설 이후 연중 수개월 정도 침수되면서 수분에 의한 풍화작용으로 암각화가 훼손되는 것에 대해 많은 논쟁이 있었다. 본 연구는 반구대 암각화 기반암의 수분등치선도를 작성하여 절리나 박락(剝落) 분포와의 관계를 검토하였다. 반구대 암각화의 함수율은 전체적으로 상부에서 하부로 갈수록 높았다. 이것은 침수된 기간의 길이와 관계된 것이다. 그리고 절리 밀도가 높은 암각화의 상부도 함수율이 높았다. 암석 내 흡수율이 증가하면 투수계수와 공극률이 증가하므로 함수율은 증가한다. 침수로 인해 암석 내에 공극들이 주기적으로 물로 포화되는 반구대 암각화는 수분에 의한 풍화로 훼손이 매우 심각한 상태이다.

• 한국결정성장학회지
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• 제16권5호
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• pp.222-226
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• 2006

Carboxylated styrene-butadiene계 액상 첨가제가 칼라 보도 블록 무기 안료층의 미세구조, 기계적 특성 및 탈색 저항성에 미치는 영향에 대하여 조사하였다. 액상 첨가제를 첨가함에 따라 겉보기 기공률과 흡수율이 감소한 더 치밀한 미세구조와 균일한 안료 분포를 나타내는 무기 안료층을 얻을 수 있었다. 또한 기계적 강도 및 탈색저항성이 현저히 향상됨을 확인하였다.

• Membrane and Water Treatment
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• 제6권5호
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• pp.423-437
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• 2015

Polyvinylidene fluoride/fullerene nanoparticle (PVDF/$C_{60}$) composite microfiltration (MF) membranes were fabricated by a non-solvent induced phase separation (NIPS) using N, N-dimethylacetamide (DMAc) as solvent and deionized water (DI) as coagulation solution. Polyvinylpyrrolidone (PVP) was added to the casting solution to form membrane pores. $C_{60}$ was added in increments of 0.2% from 0.0% to 1.0% to produce six different membrane types: one pristine PVDF membrane type with no $C_{60}$ added as control, and five composite membrane types with varying $C_{60}$ concentrations of 0.2, 0.4, 0.6, 0.8 and 1.0%, respectively. The mechanical strength, morphology, pore size and distribution, hydrophilicity, surface property, permeation performance, and fouling resistance of the six membranes types were characterized using respective analytical methods. The results indicate that membranes containing $C_{60}$ have higher surface porosity and pore density than the pristine membrane. The presence of numerous pores on the membrane caused weaker mechanical strength, but the water flux of the composite membranes increased in spite of their smaller size. Initial flux and surface roughness reached the maximum point among the composite membranes when the $C_{60}$ concentration was 0.6 wt.%.