• 폴리머
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• 제34권5호
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• pp.430-433
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• 2010

리튬이온 전지에 사용되는 가스켓 재료는 내전해액성, 전기절연성, 압축 영구 줄음률, 비오염성, 저온성이 요구된다. 가스켓 고무에 적용되는 충전제의 특성을 살펴보기 위하여 EPDM(ethylene propylene diene monomer), NBR(nitrile butadiene), FKM(fluoro elastomers)에 카본블랙 및 실리카계 충전제의 함량을 조정하여 compoud를 만들었다. 이렇게 배합된 compound를 리튬이온 전지의 작동 환경을 고려하여 전해액에 대한 장기평가 및 압축 영구 줄음률, 저온성에 대한 평가를 실시하였다. 본 실험에서는 카본블랙 및 실리카계 충전제를 사용하여 각 충전제에 따른 고무재료의 물리적 화학적 특성에 대하여 검토하였다.

• 신재생에너지
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• 제18권2호
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• pp.1-8
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• 2022

This study aimed to determine the optimal conditions for fabricating pitch pine (PCP) and Mongolian oak (MOK) pellets using chestnut-shell tea waste (CSW) and castor oil (CSO) as additives. For pellets fabricated using a pilot-scale flat-die pellet mill, all moisture content (MC) was in line with A1 wood pellet standards for residential and small-scale commercial uses designated by the National Institute of Forest Science at the Republic of Korea (NIFOS), regardless of fabricating conditions; the durability of PCP pellets prepared using PCP particles with 10% MC, and CSW addition also satisfied these criteria. The moisture tolerance of PCP pellets improved with combination of 2 wt% CSW and 2-6 wt% CSO. Overall, use of 20 mesh CSW as an additive, PCP with 10% MC, and MOK with 12% MC was found to be optimal. Moreover, using CSO as an additive, high-quality PCP and MOK pellets can be fabricated by adjusting the particles to 12% MC. However, the durability of PCP and MOK pellets prepared using these conditions did not meet the wood pellet standards for residential and small-scale commercial use. Therefore, further research is needed to improve the durability of these pellets.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2003년도 학술대회지
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• pp.152-157
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• 2003

This study represents the newly advanced formulation of hydraulic fluids for extended drain interval and introduces the performance results of used oil samples from various excavators. The used oil samples, in this paper show that there is a sharp change in viscosity drop and moderate additive depletion when viscosity index of hydraulic oil is very high. For the extension of hydraulic fluid life, it is necessary to improve the stability of viscosity and oxidation. New target properties from the used oil analysis were proposed for extended life. Performance of newly developed hydraulic oil based on used oil analysis is compared with previously used one. The properties of new formulation are the viscosity index of 140 and improved thermal stability consists of VHVI base oil. Field test results showed the possibility of extension of fluid life. Additionally, for development of high performance product, new required properties and performances were discussed.

• Tribology and Lubricants
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• 제37권6호
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• pp.203-207
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• 2021

This study presents the development of dielectric constant sensors to measure lubricant properties. The lubricant oil sensor is used to measure oil properties and machine conditions. Various condition monitoring methods are applied to diagnose machine conditions. Machine condition monitoring using oil sensors has advantage over other machine condition monitoring methods. The fault conditions can be noticed at the early stages by the detection of wear particles using oil sensors. Therefore, it provides an early warning in the failure procedure. A variety of oil sensors are applied to check the machine condition. Among all oil sensors, only one sensor can measure the tendency of several properties such as acidity and water content. A dielectric constant sensor is also used to measure various oil properties; therefore, it is very useful. The dielectric constant is the ratio of the capacitance of a capacitor using that material as a dielectric to that of a similar capacitor using vacuum as its dielectric. The dielectric constant has an effect on water content, contaminants, base oil, additive, and so forth. In this study, the dielectric constant sensor is fabricated using MEMS process. In the fabrication process, the shape, gap of the electrode array, and thickness of the insulation material are considered to improve the sensitivity of the sensor.

• Natural Product Sciences
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• 제16권3호
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• pp.175-179
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• 2010

The present study aimed to assess the antifungal properties of the essential oil fraction from Ligusticum chuanxiong (Umbelliferae) and its components against five clinically important Aspergillus species. The essential oil fraction was extracted from the underground parts of the plant by steam distillation, and its main components, namely, Z-ligustilide, butylidene phthalide, and p-cresol were isolated by column chromatography. The antifungal activities of the essential oils were evaluated by the broth dilution method. Both the total essential oil fraction of L. chuanxiong and its components showed significant anti-Aspergillus activity against all five tested strains with MICs between 62.5 and 250 ${\mu}g$/ml, respectively. In a checkerboard microtiter assay, the combination of antibiotics, itraconazole with the essential oil fraction of L. chuanxiong or its main components exhibited synergistic or additive, and in some cases indifferent, effects against the tested Aspergillus species, resulting in FICIs (fractional inhibiting concentration indices) ranging from 0.12 to 2, while the combination of antibiotics, amphothericin B with L. chuanxiong essential oils mostly showed antagonistic effects.

• Journal of Advanced Marine Engineering and Technology
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• 제40권9호
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• pp.762-767
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• 2016

디젤엔진은 다른 엔진과 비교했을 때 열효율이 높고 다양한 연료를 사용할 수 있다는 장점을 가지고 있다. 하지만, 대기오염을 유발하는 배기배출물이 발생한다는 단점도 가지고 있다. 따라서 전 세계적으로 디젤엔진을 사용하는 승용차 및 상용차, 선박 등에 대한 국제규정인 EU Euro 6, IMO MEPC Tier 3 및 US EPA Tier 4 등의 대기환경오염법이 더욱 엄격해져가고 있다. 본 연구에서는 경유를 사용하는 발전용 4행정 디젤엔진을 실험 대상으로 하였으며, 유용성 Ca계 유기금속화합물을 경유에 투입하여 실험 결과를 비교, 분석하였다. Ryu et al. 논문에서는 2행정 디젤엔진에 연료첨가제를 적용했던 연구결과를 발표하였다. 본 논문에서는 4행정 디젤엔진에 연료첨가제를 투입하여 엔진의 성능 및 배기배출물 개선에 대해서 실험을 실시하였다. 본 연구를 통해서 2행정과 4행정 디젤엔진 모두에 연료첨가제를 적용하여 그 결과를 고찰해 볼 수 있었으며 유용성 Ca계 유기금속화합물 연료첨가제가 디젤엔진의 성능(연료소비율, 배기온도) 및 배기배출물(질소 산화물, 일산화탄소)을 개선시킬 수 있음을 확인할 수 있었다.

• Food Science and Biotechnology
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• 제15권6호
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• pp.884-888
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• 2006

In this study, we have attempted to characterize the effects of encapsulated mustard oil with regard to the extension of the shelf life of kimchi. The quantity of mustard oil or encapsulated mustard oil added to the brined cabbage in this study was 0.05%(w/w). Overall, the fermentation processes in the encapsulated mustard oil-added kimchi (EMO) and mustard oil-added kimchi (MO) occurred at a slower rate than in the controls. The periods during which the MO and EMO kimchi samples were edible were prolonged for more than two weeks, according to measurements of pH, total acidity, and microbial changes. The overall acceptability of EMO was superior to MO throughout the entirety of the fermentation period. Sensory evaluation verified that EMO yielded a more favorable product than the MO and control varieties. Encapsulated mustard oil can be employed as a natural food additive to prolong the shelf life of kimchi, via an induced delay of the fermentation process.

• Natural Product Sciences
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• 제14권2호
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• pp.138-142
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• 2008

The composition of essential oils from Chrysanthemum zawadskii var. latilobum and C. indicum were analyzed and compared. The results of gas chromatography-mass spectrometry revealed there were distinctly different compositional patterns between C. zawadskii var. latilobum and C. indicum essential oils. The combinatorial effect of the oil of C. zawadskii var. latilobum and C. indicum, with various antibiotics was assessed against antibiotic-susceptible and -resistant strains of Staphylococcus aureus and Streptococcus pneumoniae. The essential oil fraction significantly inhibited most of the tested antibiotic-susceptible and -resistant strains of S. pneumoniae, with minimum inhibiting concentrations (MICs) ranging from 0.5 to 4.0 mg/ml. The fractional inhibiting concentration indices (FICIs) of the oils when combined with antibiotics against S. aureus and S. pneumoniae ranged from 0.26 to 0.75, and showed synergistic or additive effects.

• Natural Product Sciences
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• 제17권4호
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• pp.296-302
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• 2011

We determined the inhibitory activity of the essential oil fraction obtained by steam distillation from the fresh and dried leaves of Perilla frutescens var. acuta against some pathogenic Salmonella and Vibrio spp. The activities of compounds isolated from the essential oils, apiol and myristicin, were also tested and the results were compared with those of the essential oil fraction. The Perilla essential oil fraction and its main components showed significant inhibition against antibiotic-susceptive and antibiotic-resistant strains of the tested Salmonella and Vibrio strains. Synergistic or additive effects were identified by combing the oils with ampicillin by checkerboard-titer tests. We conclude that essential oils from P. frutescens can be useful in the treatment of Salmonella and Vibrio infections and as safe additives to food materials for the prevention of contamination of food by these bacteria. This is especially important because of the rapid increase in antibiotic-resistant strains, which could cause severe symptoms in humans.

• 한국산학기술학회논문지
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• 제8권2호
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• pp.167-172
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• 2007

자동차의 가혹한 운전조건하에서 사용되는 기어오일의 경우 시져(소부 : seizure)에 잘 견디고 내구성을 증가시키기 위하여 여러 가지 첨가제들을 사용한다. 본 논문에서는 자동차 기어오일에 $MoS_2$를 첨가하고, 펠렉스 마찰 마모시험기를 사용하여 마찰마모 특성을 고찰하였다. 실험결과 $MoS_2$의 함유량이 2.5-5wt.%일 때 마찰 마모특성이 가장 우수하였다.