• Korean Chemical Engineering Research
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• 제52권1호
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• pp.88-91
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• 2014

본 연구에서는 Nannochloropsis oceanica로부터 바이오디젤 원료유로 활용하기 위한 미세조류 오일을 추출하였다. 용매추출법을 이용하여 오일을 추출하였으며, 미세조류의 건식 및 습식 조건에서 오일 추출률(yield) 및 오일 추출 효율(efficiency)을 비교하였다. N. oceanica는 지방산 함량이 317.8 mg/g cell으로 건조중량 대비 30% 이상의 높은 오일함량을 나타내었으며, 미세조류의 건식 조건에서 습식 조건보다 높은 오일 추출률을 나타내었다. 사용된 용매에 대해서 헥산 < 헥산-메탄올 < 클로로포름-메탄올 순으로 오일 추출률이 증가하였다. 그러나 추출된 오일의 지방산 함량을 분석한 결과, 오일 추출률이 증가할수록 지방산 함량은 감소하여 엽록소와 같은 불순물을 포함하고 있는 것으로 나타났다. 따라서 오일 추출률과 지방산 함량을 고려한 오일 추출 효율은 건식 조건에서 헥산-메탄올 이용 추출에서 82.6%의 가장 높은 효율을 나타내었고, 습식 조건에서는 클로로포름-메탄올 이용 추출에서 88.0%로 가장 높은 효율을 나타내었다. 따라서 경제적으로 미세조류의 건조가 가능한 경우에는 헥산-메탄올을 사용하고, 건조 비용이 높은 경우에는 습식 조건에서 클로로포름-메탄올을 사용한 용매추출법이 바람직하다.

• 한국항해항만학회지
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• 제46권3호
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• pp.289-296
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• 2022

본 연구의 목적은 유가와 벌크선 운임의 상관관계 및 영향력을 검증하는 것이다. 탄소배출 감축을 위해 석유의존도를 줄이고 친환경연료 선박의 개발이 추진되고 있지만, 현재의 진행상황으로 볼 때, 상당한 시간이 필요할 것으로 보인다. 반면, COVID 19 팬데믹 및 러시아의 우크라이나 침공에 따른 유가 변동성이 커지고 있다. 해운업에서 연료비용이 큰 비중을 차지하고 있으므로, 유가가 운임에 어떠한 영향을 주는지 점검이 필요하다. 유가 변수로 Brent, Dubai, WTI 그리고 운임변수는 BDI, BCI, BPI로 2008년 10월부터 2022년 2월까지 월별 데이터를 사용하였다. VAR(Vector Autoregressive) 모형을 이용한 상관관계 분석에서 BDI에 대한 충격반응 분석은 WTI가 가장 큰 영향을 미쳤고, 그 다음으로 두바이유, 브렌트유 순으로 차이를 보였다. 예측오차 분산분해 분석결과는 BDI에 대해 WTI, 두바이유, 브렌트유 순으로 설명력의 차이를 보였다. 선종별로 차이는 있으나, 대체로 WTI와 두바이유가 설명력이 높았다.

• Carbon letters
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• 제12권4호
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• pp.249-251
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• 2011

Carbon/epoxy woven composites are prominent wear-resistant materials due to the strength, stiffness, and thermal conductivity of carbon fabric. In this study, the effect of oilabsorption on the wear behaviors of carbon/epoxy woven composites was investigated. Wear tests were performed on dry and fully oil-absorbed carbon/epoxy woven composites. The worn surfaces of the test specimens were examined via scanning electron microscopy to investigate the wear mechanisms of oil-absorbed carbon/epoxy woven composites. It was found that the oil absorption rate was 0.14% when the carbon/epoxy woven composites were fully saturated. In addition, the wear properties of the carbon/epoxy woven composites were found to be affected by oilabsorption. Specifically, the friction coefficients of dry and oil-absorbed carbon/epoxy woven composites were 0.25-0.30 and 0.55-0.6, respectively. The wear loss of the oilabsorbed carbon/epoxy woven composites was $3.52{\times}10^{-2}\;cm^3$, while that of the dry carbon/epoxy woven composites was $3.52{\times}10^{-2}\;cm^3$. SEM results revealed that the higher friction coefficient and wear loss of the oil-absorbed carbon/epoxy woven composites can be attributed to the existence of broken and randomly dispersed fibers due to the weak adhesion forces between the carbon fibers and the epoxy matrix.

• 한국식품영양과학회지
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• 제32권5호
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• pp.655-660
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• 2003

건조새우를 볶는 과정 중에 옥수수기름의 첨가에 따른 향기성분변화를 검토하고자 건조새우와 건조새우 중량에 옥수수 기름을 각각 10%, 25%씩 첨가한 시료를 18$0^{\circ}C$에서 7분간 가열하였다. 마른새우 및 가열한 3개 시료의 향기성분을 연속수증기증류방법으로 추출하였다. 확인된 향기성분은 14개의 aldehyde와 pyrazine과 pyridine이 각 7개 그리고 5개의 alcohol과 3개의 pyrrole 등 총 52개 이었다. 확인된 모든 성분중에서 그 함량과 향기성분의 수가 가장 많은 것은 aldehyde류이었다. 기름을 첨가하여 가열한 시료에서는 지방산 사슬에서 기인된 heptenal, trans-2-heptenal, nonanal, trans-2-decenal, trans, cis-2,4-decadienal, trans, trans-2,4-deca-dienal과 1-octen-3-ol, 2-pentylfuran 등의 지질 분해산물이 관찰되었다. 새우의 독특한 향기성분을 나타내는 함질소 화합물인 pyrazine, pyridine, pyrrole 등은 마른 새우에서는 검출되지 않았으나 가열하여 볶은 새우에서 확인되었으며 옥수수 기름을 10 g 첨가하여 볶은 시료에서 그 함량이 가열한 시료보다 조금 더 증가하였으며 259의 기름을 첨가한 시료에서 가장 많이 나타났다. 이 결과는 첨가된 옥수수 기름에서 기인된 aldehyde류가 시료의 아미노산과 반응하여 바람직한 함질소 향기성분 생성에 기여한 것이라고 할 수 있다.

• 한국조리학회지
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• 제12권3호
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• pp.108-118
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• 2006

This study is on different dry methods for Artemisia sp. which were not affected by the dry matter percent. Essential oil components such as 1,8-cineol and terpineol were highly affected by the dry method. 1,8-cineol and terpineol components were decreased by adaptation of the heated oven-drying method and the freeze-drying method. Borneol components were increased through shady sun-drying, sun-drying and freeze-drying. Heated oven drying method decreased the vitamin C content. Vitamin C content was decreased in oven-drying about 50% during this period, but only 10% decreased in the freezing dry method. Qualities were changed by different drying methods. Therefore, different dry methods of Artemisia sp. were applied to the flavorgen.

• 한국의류산업학회지
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• 제9권5호
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• pp.569-572
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• 2007

The effectiveness of Palmarosa, Neroli and Jasmin blending oil on dry skin of rat induced by kitchen detergent are investigated. The experimental groups were divided the control group, group treated with surfactant, group treated with Palmarosa and Neroli, and group with Palmarosa, Neroli and Jasmin. Observation of epidermis and the alteration of mast cell were performed with photomicroscope. According to the epidermis morphological changes analysis, the A3 group treated with Palmarosa, Neroli and Jasmin blending oil was appeared the most similar with the control group, and the A2 group applied with Palmarosa and Neroli blending oil was sequently displayed similar characteristics. The collagen layer's breakaway resulting from Palmarosa essential oil, the collagen layer's restoration resulting from Neroli essential oil, the collagen layer's retention hyperkeratosis resulting from Jasmin essential oil were observed in the structure of the epidermal layer. In photomicrosope observation of mast cell to examine the inflammatory reactions, the increase in size and number of mast cell were showed in A1 group treated with surfactant compared to the control group. The number of mast cells definitely decreased in groups which were treated with Palmarosa, Neroli and Jasmin blending oil.

• Asian-Australasian Journal of Animal Sciences
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• 제12권2호
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• pp.209-214
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• 1999

Grazing preference, voluntary dry matter intake, stocking rate and digestibility of forage were investigated or sheep grazed in mature oil palm plantations in Malaysia. Dry matter intake (DMI) was estimated using the chromium sesquioxide marker method. The sheep were allowed to graze about 5 hours/day in oil palm plantations of age ranging from 9 to 21 years old. The crude protein, crude fibre and ash contents of selected herbage were 13.1 %; 24.6 %; and 8.3 %, respectively, while the gross energy (GE) and the metabolisable energy (ME) were 16.9 and 6.0 MJ/kg DM, respectively. Broad leaf plants and grasses were normally found in plantation of all ages. Legumes and oil palm seedlings formed the smallest group in the whole mixture. Fern content increased in older plantations. Legumes, oil palm seedlings, fern, broad leaves and grasses were 0.4, 1.3, 11.4, 28.0 and 59.0 %, respectively of total herbage. Grasses showed the highest preference index followed by broad leaf plants, legumes, oil palm seedlings and ferns in that order. The DMI and the metabolisable energy intake (MEI) of sheep at 6, 8, 10, 12 and 14 months of age were 64.8, 65.0, 65.3, 65.6 and 67.4 g/kg $W^{0.75}$ (p<0.05) and 0.39, 0.40, 0.40, 0.40 and 0.41 MJ/kg $W^{0.75}$, respectively. The average stocking rate was 4.3 sheep/ha. It was concluded that the performance of the sheep could be improved by increasing the daily grazing period and also by appropriate concentrate supplementation.

• 한국연초학회지
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• 제23권1호
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• pp.65-70
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• 2001

In order to compare the extraction patterns of main components from the raw material between the extraction methods, the aerial parts (dried stem, leaves, and flowers) of Agastache rugosa were extracted by SDE simultaneous steam distillation & extraction) and SFE (supercritical fluid extraction). Volatile components of essential oil and extract were identified by GC and GC-MSD. The contents of essential oil extracted by SDE were 0.49% in aerial part of Agastache rugosa on dry basis. Major components were methyl chavicol(27.2%), isomenthone(24.6%), hexadecanoic acid(13.0%). menthone (5.5%) among 32 kinds of components confirmed in essential oil. On the other hand, the contents of SFE extracts revealed 3.21% on dry basis, 6 times higher than those of SDE. Major components were isomenthone(15.3%), hexadecanoic acid(13.7%), methyl chavicol(12.6%), benzoic acid(3.8%) among 33 kinds of components identified in extract.

• 한국기계가공학회지
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• 제1권1호
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• pp.48-54
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• 2002

In industrially advanced countries, environmentally conscious machining was eagerly studied because of ecological and economical reasons. As the environmental regulations become stricter, new machining technologies which take environmental aspects into consideration are being developed Industry and research institutions established applications for dry, semi-dry, oil-mist and compressed cold air machining. This paper investigates the performance of new compressed cold air system for environmentally conscious machining and evaluates machinability of dry and new compressed cold air machining. A series of tests are carried out using measuring eqipments under dry and compressed cold air machining.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.1008-1011
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• 2002

In industrially advanced countries, environmentally conscious machining was eagerly studied because of ecological and economical reasons. As the environmental regulations become stricter, new machining technologies which takes environmental aspects into consideration are being developed. Industry and research institutions established applications for dry, semi-dry, oil-mist and compressed cold air machining. This paper investigates the performance of new compressed cold air system for environmentally conscious machining and evaluates machinability of dry and new compressed cold air machining. A series of tests are carried out using measuring equipments under dry and compressed cold air machining.