• 한국의류학회지
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• 제18권4호
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• pp.524-535
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• 1994

The interaction and detergency between oily soil and surfactant solution were studied Samples used were tristearin, tripalmitin and their mixture as a triglyceride, myristic acid as a fatty acid and sodium dodecyl sulfate (SDS) as surfactant. The results were as follows: 1. The mixtures of model oily soils were formed of eutectic point and their melting point were lower than them of individual oily soils. 2. The formation of liquid crystalline (LC) phase was recognized in the triangle phase diagram for SDS~ water~model oily soil system. The areas of LC phase region were in the order of SHS~ water~myristir acid> SDS~ water~mixture of tristearin, tripalmitin and myristic acid (TS/TP/M)>SDS~water~mixture of tristearin and tripalmitin (TS/TP) 3. The LC phase region expanded to wide concentration range of SDS solution and high concentration range of model oily soil with increasing temperature. Particularity, the LC phase region expanded highly at $30~40^{\circ}C$ but when the temperature was elevated above $40^{\circ}C$, expanding tendency decreased. 4. In the system of myristic acid and TS/TP/M contacted with SDS solution, the LC phase was already formed at $28^{\circ}C$ and the region of the LC phase were expanded with increasing temperature. But in the system of TS/TP contacted with SDS solution, the LC phase was not formed in whole experiment temperature. 5. The detergency of myristic acid was very high ann it was recognized that the formation of the LC phase played an important role in the detergency. The detergency of TS/TP was very for low, but when TS/TF was mixed with myristic acid, the detergency of TS/TP increased. It is supposed that the LC phase was formed butween SDS solution and myristic acid promoted to penetration of SDS solution into the inner parts of TS/TP.

• 원예과학기술지
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• 제31권2호
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• pp.239-245
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• 2013

Occupational exposure and risk assessment were conducted to evaluate the safety of operators when insecticide acetamiprid was applied to apple orchard using a speed sprayer. Dermal patches, cotton gloves, socks, and masks were used to monitor the dermal exposure, and personal air pump with solid sorbent was used to measure the potential inhalation exposure. In validation to analytical methods, the limit of detection and limit of quantitation were 0.25 ng and 1 ng, respectively. Good reproducibility (coefficient variation < 4%), linearity (coefficient determination > 0.999), and recovery (85.3-118.2%) were obtained. Trapping efficiency of solid sorbent was 96.4% while breakthrough did not occur. Only hand exposure was measured on the gloves during mixing/loading to give $33-1,132{\mu}g$. Exposure amount of operator 3 among 4 workers was noticeably high. The total volumes of spray liquid for operators were $535-1,235mL{\cdot}h^{-1}$, corresponding to 0.03-0.08% of the applied spray solution. Highest contaminated parts of body were thighs, chest, and lower legs. The inhalation exposure ratio to the total application amount was significantly low. However, wind seemed to affect the inhalation exposure of operator. For risk assessment, margin of safety was calculated by the application of cloth and dermal penetration rate to obtain values of much larger than 1 in all cases. Therefore, health risk of operators during treatment of acetamiprid in apple orchard could be of least possibility.

• 펄프종이기술
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• 제34권2호
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• pp.1-12
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• 2002

Starch dissolved in paper-mill wastes, either as a result of poor retention on the paper web or recycling of surface-treated broke, was a major pollutant Laboratory tests were performed by using different kinds of starch as a surface treatment. It was concluded that the use of cationic starch can positively affect the level of starch dissolved in liquid effluents. When cationically modified starches were used for surface sizing, the starch was tightly bound to the paper fibers, it was not removed during the repulping of broke. The result of mill trial in fine paper manufacture for the application of low-viscosity cationic starches used in size press reduced COD load in the effluents and increased One Pass Retention. It had been found that when cationic starch used as a surface sizing agent, more starch was retained on or near the surface of the sheet than with conventional oxidized starches. Thus surface strengths and quality were improved. In addition it is possible to maintain the desired level of starch penetration into the fiber net and improve porosity, opacity and brightness. In contrast, in most cases, dusting problems are notably eliminated. Cationic surface sized starch improved black and color ink-jet print quality in terms of feathering and optical density of the print image. These improved properties were believed to be due to a combination of fiber bonding and surface orientation more uniform starch concentration on the paper surface was resulted. Moreover cationic charges in the paper surface lend themselves excellently to fix ink jet ink anionic in nature.

• 한국응용과학기술학회지
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• 제31권2호
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• pp.167-175
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• 2014

혼탁매질에서 형광, 산란과 응집의 영향은 파장과 산란된 형광세기로 나타내는데, laser induced fluorescence(LIF) 분광학에 의한 분자특성으로 나타난다. 산란매질에서 광학적 효과는 광학적 파라미터들(${\mu}_s$, ${\mu}_a$, ${\mu}_t$)에 의해 표현되고 응집은 고-액상 분리공정과 Photodynamic therapy에서 중요하게 활용되고 있다. 따라서 입자가 서로 접근될 때 콜로이드 입자들의 상호작용을 LIF와 응집효과로 분석하였다. 우리는 레이저 광원에서 검출기까지 농도의 함수에 의해 in vitro 시료의 산란과 형광 스펙트라를 측정하였다. 산란계수 ${\mu}_s$는 산란체의 입자가 증가함에 크게 나타났다. 그리하여 Phorphyrin A는 Phorphyrin C보다 산란세기는 증가하였으나, 침투깊이 ${\delta}$는 감소하였다.

• 한국산학기술학회논문지
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• 제16권10호
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• pp.6816-6822
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• 2015

본 연구에서는 기존의 글라스울의 흡습에 의한 변형을 해결하고 단열성능향상을 위해 실리카 에어로젤을 이용한 단열재를 개발하였다. 글라스울 단열재에 액상의 혼합 바인더를 이용하여 실리카에어로젤이 함침된 글라스울 복합체를 제조하였다. 액상의 혼합 바인더는 수용성바인더(CMC, carboxymethyl cellulose)와 물에 분산시킨 실리카 에어로젤을 이용하여 준비하였다. 초기 $0.048g/cm^3$의 밀도를 갖는 글라스울 보드를 준비하고 실리카 에어로젤을 함침시켜 $0.065g/cm^3$의 밀도를 갖는 단열보드를 제작할 수 있었다. 이렇게 제조된 실리카 에어로젤 함침 글라스울 보드 복합체는 단일 글라스울 보드의 단열성능보다 7.4% 향상된 0.0315 W/mK의 열전도율(thermal conductivity)을 나타내었다. 제조된 실리카 에어로젤-글라스울 복합체는 불꽃 관통시험에서 362초간 내화 저항성을 나타내어 단일 글라스울 보드에 비하여 2.7배나 높은 내화성능을 보였다. 또한 일반 글라스울 보드는 흡습에 의하여 수직방향으로 처짐현상을 나타내는 단점이 있었으나, 실리카 에어로젤이 함침된 보드에서는 실리카 에어로젤의 발수특성으로 인하여 높은 내수성능을 나타내는 것을 확인하였다.

• 한국도로학회논문집
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• 제7권3호
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• pp.53-62
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• 2005

겨울철 원활한 제설작업은 겨울철 도로운영 및 관리에 중요한 공정이다. 현재 우리나라에서는 염화칼슘을 제설제로 가장 많이 쓰고 있고, 성능은 우수하지만 환경문제와 부식으로 인한 도로주변의 콘크리트 구조물의 내구성을 저하시키는 원인이 되고 있어 심각한 문제가 되고 있다. 한편 유기성 폐기물을 이용하여 환경친화 제설제인 Ca, Mg와 유기산(초산, 프로피온산)의 반응물인 유기산염 (CMO, Calcium magnesium salt of organic acids)으로 구성된 제설제의 경우 자원 재활용으로 인한 생산 단가를 낮출 수 있고 환경문제와 구조물의 내구성저하를 해결할 수 있다는 연구들이 수행된 바 있다. 본 연구에서는 실험실에서 화학조성에 의해 샘플로 제조된 환경친화 제설제인 유기산염(CMO의 일종)과 미국에서 개발한 CMA, 기존 제설제에 대해 제설에 필요한 기초물성에 대한 실험과 성능 실험을 통해 융빙성능을 비교 분석하였고 콘크리트 표면의 중량 손실량 실험을 통하여 구조물의 내구성에 미치는 영향을 검토하였다. 결과 분석을 통해 CMO의 융빙성능은 기존 제설제인 염화칼슘에 비해 60$\sim$90% 정도의 효과를 보였다. 중량손실효과는 미미하여 구조물의 내구성에 영향을 거의 미치지 않음을 알 수 있었다.

• 한국구조물진단유지관리공학회 논문집
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• 제21권1호
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• pp.74-82
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• 2017

본 연구에서는 시멘트 복합체의 균열을 자기치유 할 수 있는 자기치유 캡슐을 제조하기 위한 일환의 기초 연구로써 자기치유 캡슐용 코어재료에 무기계 기반 코어재료를 적용하기 위하여 액상형태의 무기 소재를 기반으로한 코어재료를 제조하였다. 제조된 무기계 기반 코어재료는 캡슐화를 진행하기 전에 무기계 기반 코어재료를 직접 시멘트 복합체에 적용하여 균열부의 균열수복 성능뿐만 아니라 시멘트 복합체의 성능에 미치는 영향을 검토하였다. 평가결과, 무기계 기반 코어재료는 압축 및 부착강도 향상효과가 있는 것을 확인하였으며, 부착, 내흡수, 내투수 및 동결융해 저항 성능을 가진 것으로 판단된다. 본 논문의 결과를 통하여 자기치유 캡슐용 무기계 기반 코어재료를 적용할 경우에 얻을 수 있는 시멘트 복합체의 성능 및 차후 진보화된 자기치유 캡슐기술의 기반 자료로써 활용하고자 한다.

• 한국농공학회지
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• 제39권1호
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• pp.102-111
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• 1997

Experiments both in laboratory and field were performed to compare and analyze the characteristics of alluvial clay. The alluvial clay was sampled in test site in which large-scaled tests for the part of the site are under process to suggest the rational method for alluvial clay and the criterion for ground settlement monitoring system. The followings were observed through the experiments : 1. Natural water content, plastic limit, and liquid limit of alluvial clay composed of highly fine grains were 40~80%, 10~20%, and 30~55%, respectively. The values of these properties were relatively small at the ground surface, while the values showed maximum at G.L.- l0m and gradually decreased below the level. 2. Shear strength of alluvial clay was proportionally increased to the depth. Unconfined and triaxial compressive strengths were 0.2~0.6kgf/$cm^2$ and 0.1~0.3kgf/$cm^2$, respectively. 3. Compression index and secondary compression index showed maximum values at G.L.-l0m and gradually decreased below the level. The value of consolidation coefficient was relatively large at the ground surface, constant with decreasing the depth, and incresed when G.L. was below -20m. 4. Piezocone test appeared that alluvial clay with N value of 2~4 was uniformly distributed with 20~ 30m thickness from the ground surface, sand seam was nonuniformly distributed, and penetration pore pressure was 0.8 ~ 1 times of the hydrostatic pressure. Undrained shear strength and consolidation coefficient were 0.04 ~ 0.76kgf / $cm^2$ and $2.88{\times} 10{^-4}~1.3{\times} 10{^-2} cm^2/s$ respectively.

• Environmental Engineering Research
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• 제24권4호
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• pp.630-637
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• 2019

The present study aimed to investigate the potential of Enterococcus faecalis (E. faecalis) and Bacillus cereus (B. cereus) in improving the properties of bio-concrete. E. faecalis and B. cereus strains were obtained from fresh urine and an acid mire water at cell concentration of 1.16×10¹² and 1.3×10¹² cells mL^-1, respectively. The bacterial strains were inoculated in a liquid medium into the concrete with 1, 3 and 5% as replacement of water cement ratio (w/c). The ability of E. faecalis and B. cereus cells to accumulate the calcite and the decrement of pores size within bio-concrete was confirmed by SEM and EDX analysis. The results revealed that E. faecalis exhibited high efficiency for increasing of compressive and splitting tensile strength than B. cereus (23 vs. 14.2%, and 13 vs. 8.5%, respectively). These findings indicated that E. faecalis is more applicable in the bio-concrete due to its ability to enhance strength development and reduce water penetration.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book II
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• pp.330-342
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• 2003

The formation of emulsions and micelles in water/ceramide PC104/CholE $O_{20}$/C$_{16}$E $O_{20}$ and water/ceramide PC104/CholE $O_{20}$ mixtures was investigated through the phase behavior studies. The phase diagrams showed the existence of micelle and emulsion regions in both systems. The mixed surfactant system (CholE $O_{20}$/C$_{16}$E $O_{20}$) showed the wider micellar and emulsion regions than the single surfactant system (CholE $O_{20}$). From FT-IR measurements, it was found that the polyoxyethylene (POE) groups of surfactants formed the hydrogen bonds with amido carbonyl group in ceramide PC104. This result indicated that the hydrophilic part (EO) of surfactants could stabilize the lamellar structure and emulsion of ceramide PC104. The mixed surfactant system (CholE $O_{20}$/C$_{16}$E $O_{20}$) resulted in the smaller emulsion droplet size due to the effect of curvature at the interface, thus further increasing emulsion stability. With the penetration of $C_{16}$E $O_{20}$into the interfacial layer of surfactants in emulsion, the curvature of the interface might be altered for the formation of smaller emulsion droplets. The mixed surfactant system could incorporate up to 4 wt. % of ceramide PC104 into emulsion more than single surfactant system.ystem.m.