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        검색결과 1,201

        7.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Analyzing and diagnosing the causes of abnormal conditions through control logic processes at the plant site is critically important. When a process is halted, the steps for cause analysis and corrective action vary depending on the operator's experience and the specific characteristics of the process. Since it's often not feasible to keep the process stopped for an extended period, issues are sometimes resolved by forcibly restarting the PLC(Programmable Logic Controller). However, this can lead to the recurrence of the same error, which may negatively impact process operations. In particular, oil sands development is an uncharted area with anticipated environmental challenges. In this regard, an integrated system between control systems in the oil sands production plant was established to implement control logic, develop the HMI(Human-Machine Interface), and verify the user interface. This allowed for a better understanding of the equipment's operability.
        4,000원
        8.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        해양경찰청 경비함정의 선박용 디젤기관은 MTU와 Pielstick사의 고출력 엔진으로 윤활유의 성능이 매우 중요하다. 경비함정 엔 진의 부하변동이 많고 운행시간 등이 증가되면서 열에 의한 산화 및 연료유, 수분 등 혼입으로 동점도 등 윤활유 성질이 변할 수 있다. 본 연구에서는 윤활유의 열화요인 및 영향을 파악하기 위해 경비함정 윤활유를 사용 시간별(100, 200, 300, 400 hr)로 채취하였다. 채취된 윤활유로 열화요인 분석 위해 연료 혼입량 등을 측정하였다. 또한 열화 영향 분석을 위해 동점도 등을 측정하였다. 특히 윤활유의 산화 여부를 분석하기 위해 산화 안정도 등을 확인하였다. 열화의 외부요인인 연료 혼입량의 경우 사용 시간이 늘어나면서 5.1%에서 14.0%로 증가하였으며, 이에 따라 동점도는 낮아지는 결과를 보였다. 윤활유의 사용 시간이 늘어나면서 열 및 수분 혼입에 의한 산화는 확인할 수 없었다.
        4,000원
        9.
        2024.10 구독 인증기관·개인회원 무료
        현재 도로포장 유지보수 과정으로부터 노화된 폐 아스팔트가 발생하며, 순환 아스팔트로서 재활용하기 위해 아스팔트 오일을 첨가제 등과 함께 혼합하여 노화된 아스팔트의 성상 회복 및 유동성을 개선하여 도로포 장 재료로 활용하고 있다. 또한 아스팔트 오일의 사용은 저온영역의 성능 개선에도 영향을 미쳐 개질아스팔트 제작에도 활용하고 있으며, 개질 아스팔트는 SBS(Styrene Butadiene Styrene), SBR(Styrene Butadiene Rubber)등 고무계열의 폴리머와 오일 등을 원 아스팔트에 혼합하여 아스팔트 바인더의 공용성을 향상시키는 기술로서 폴리머는 아스팔트의 고온 영역의 물성, 오일은 저온영역의 물성을 개선하는데 사용된다. 이 중 폴 리머에 관한 연구는 활발히 이루어지고 있는 반면 아스팔트에 사용하는 오일에 관한 연구는 상대적으로 연 구가 부족한 실정이다. 따라서 오일의 사용으로 인한 아스팔트의 물성 변화에 관한 실험적인 검토가 필요 하다고 판단된다.
        15.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The study investigated a method of synthesizing a pitch suitable for making activated carbon using fluid catalytic crackingdecant oil (FCC-DO), a high-purity carbon precursor from oil refining. We kept the reaction time and catalyst amount constant while varying the temperature to investigate its impact on pitch synthesis and the resulting physical and activation properties. Previous research established that materials added during pitch synthesis can affect the properties of both the pitch and resulting activated carbon. This study examined the addition of polyethylene terephthalate (PET) to FCC-DO-based pitch. The results indicated significant changes in properties with PET addition and temperature variation that ensured stable activated carbon quality. At temperatures of 390 °C or higher, the specific surface area of the activated carbon stabilized between 2680 and 2740 m2/ g. Waste PET, a recyclable plastic, was chosen due to its compatibility and thermodynamic suitability for pitch synthesis. Importantly, adding PET didn't generate additional waste or degrade the physical properties of the activated carbon.
        4,000원
        16.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Biodiesel is a traditional energy field that can replace low-quality marine fuels for ships and various studies have been conducted. Since the 2000s, Korea has introduced a mandatory supply system of biodiesel for domestic vehicle diesel, gradually raising the blending ratio from 0.5% to 3.5%, and is expected to raise the mandatory blending ratio to about 8.0% by 2030. Therefore, in this study attempted to blend high-quality samples that meet the biodiesel quality standards manufactured by domestic companies with MGO in ratios ranging from 0 to 60%. We utilized a 1-ton combustion chamber to compare and analyze the exhaust gas emissions characteristics. As a result, in the BD60 condition, which represents the maximum range in this study, the O2 increased by approximately 1.5%p, and CO2 tended to decrease by 1.1%p. NOx decreased by approximately 18.2%p from 34.1 ppm to 27.9 ppm. In the case of SOx, a very low concentration of 0.08 ppm was detected under the BD0 condition, and it was undetectable under all other conditions containing biodiesel. This suggests that MGO itself has excellent low-sulfur oil quality and can implement zero SOx through biodiesel mixing. Furthermore the combustion efficiency decreased by approximately 1.91%, from 72% to 70.2%, and the exhaust gas temperature also decreased by about 4.5%p. However despite the lower calorific value of biodiesel compared to MGO, it demonstrated relatively close thermal output per unit content. This indicates sufficient potential for biodiesel to serve as a viable alternative fuel for ships in the future.
        4,000원
        18.
        2024.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In order to maximize the function and increase the compatibility of silicone hydrogel lens, this study compared and analyzed the properties of Amino modified silicone oil using mini and microemulsion technique, respectively. Optical and physical properties were evaluated by spectral transmittance, refractive index, water content, oxygen transmittance and contact angle measurements to evaluate the performance of the manufactured hydrogel lens. The spectral transmittance results revealed the copolymerization method lens showed 31 % of the visible light area, which did not satisfy the basic optical properties. However, the lens using the mini and microemulsion materials showed more than 90 % of the visible light area, satisfying the optical characteristics. In addition, all physical properties were superior to a basic hydrogel lens. The mini and microemulsion techniques effectively improved the stability and function of the ophthalmic hydrogel lens and are considered a promising ways of manufacturing an ophthalmic hydrogel contact lens with increased compatibility and stability.
        4,000원
        19.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 국내 천연 자생 식물인 쥐오줌풀을 정유 추출하여 향기 성분 분석결과를 기반으로 항산화(DPPH, ABTS), 세포생존율(MTS), 항염(Nitric oxide)실험을 수행하였다. 향기성분 분석결과 쥐오 줌풀의 대표 유효 성분인 ester류의 bornyl acetate가 47.88%로 타지역에 비해 높은 함유량을 나타났으며 patchouli alcohol (18.9%), camphene (11.37%), camphene (11.37%), α-Pinene (5.44%), D-limonene (1.11%)등이 동정되었다. 항산화 활성인 DPPH 라디칼 소거능이 250 μl/ml에서 73.62%, ABTS 라디칼 소거능이 250 μl/ml에서 82.17%을 보였으며, 세포독성이 확인되지 않은 5 μl/ml의 농도에서 NO 생성 저해능은 대조군에 대비 62.02%로 감소함을 나타났다. 이를 통해 기능성 제품으로의 활용 가능성을 과학 적으로 검증하여 쥐오줌풀 정유를 활용한 연구분야에 일부 기여할 수 있을 것이라 기대되는 바이다.
        4,300원
        20.
        2024.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It was found in this study that fluorinated microporous carbon aerogels with enhanced hydrophobicity could be successfully prepared by direct fluorination to separate water-in-oil emulsions at high flux. The fluorinated carbon aerogel (F-CA) surface treated by the fluorination method had a water contact angle of 151.2° and could immediately absorb oil. In addition, the unique network structure of F-CA and its hydrophobicity allow surfactant-stabilized water-in-oil emulsions to be effectively and simply separated under gravity without requiring external forces such as vacuum or pressurization. The network structure of F-CAs consists of randomly connected spherical particles that form fluorinated permeation channels, which induce high flux during emulsion separation. The F-CA spherical particles have nanosized pores and high hydrophobicity, which repel and trap water droplets to increase the separation purity. Therefore, F-CA exhibited excellent performance, such as high filtrate purity (up to 99.9954%) and flux (up to 11,710 L/m2h). Furthermore, F-CA reusability was demonstrated as it did not lose its hydrophobicity and maintained its performance even after repeated use. This type of aerogel has great potential to be utilized throughout various environmental fields, including oil remediation.
        4,200원
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