• Korean Chemical Engineering Research
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• 제50권5호
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• pp.860-865
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• 2012

바이오매스 합성가스는 저열량 가스이지만 유류를 대체하기 위한 목적으로 공업로, 보일러 등에서 혼소방법으로 이용되고 있다. 혼소버너의 기본구조는 오일버너를 중심부로 하고 저열량 가스 연료를 그 주위로 공급하는 형태로 설계되었다. 본 연구에서는 가스의 균일분산 방법과 가스노즐 각도를 변화시키는 방법을 적용하여 세 종류의 버너를 설계하였다. 연소공기량 증가에 따라 CO 발생량이 감소하였으며, 혼소조건에서 화염으로부터 잔염 발생 원인은 오일버너로부터 미립화 불량인 것으로 나타났다. 혼소조건에서는 가스와 오일연료에 대한 과잉공기 요구량이 서로 다르기 때문에 적절하게 연소공기량을 맞추기가 어려웠지만, 과잉산소 4.7~8.2% 범위에서 안정적인 연소조건 유지가 가능하였다. 본 연구를 통하여 합성가스와 유류의 혼소 이용은 합성가스 성분이 오일보다 연소속도가 빠르게 이루어져 오일버너 미립화를 촉진시켜주고, 오일 단독연소조건보다 CO 배출 농도를 낮게 유지할 수 있음을 알 수 있었다.

• Journal of Ecology and Environment
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• 제35권3호
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• pp.195-201
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• 2012

Seasonal variations in the profile and concentrations of essential oil in Zanthoxylum piperitum were investigated by gas chromatography-mass spectrometry. Seasonal changes in the percentages of the main constituents of the essential oil of both leaves and fruits from Z. piperitum varied. Variations in essential oil yield and the amount of monoterpenes and sesquiterpenes in leaves and fruits at different developmental stages were significant. The characteristic content of essential oil in leaves was determined mainly due to the content of monoterpenes, and that in fruits was determined largely due to the sesquiterpenes. Twenty-nine compounds in the oil from Z. piperitum leaves were detected; the major compounds were ${\beta}$-phellandrene (26.90%), citronella (15.32%), ${\beta}$-myrcene (3.24%), ${\alpha}$-pinene (2.79%), trans-caryophyllene (2.66%), and fanesyl acetate (2.30%). The highest yield of oil (43.89%) in Z. piperitum leaves was obtained in May but decreased gradually beginning in June. The yield of essential oil from Z. piperitum leaves during early periods was higher than that during later periods and usually decreased from early maturation stages to subsequent stages. However, in contrast to leaves, the oil yield in Z. piperitum fruit increased in June, and oil yield later in the season was higher than that earlier in the season. These results indicate that the essential oil produced from Z. piperitum leaves at the early developmental stages was stored in leaves, and might be transferred to fruit at the final developmental stages.

• Tribology and Lubricants
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• 제22권4호
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• pp.211-217
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• 2006

Ring and groove wear may not be a problem in most current automotive engines. However, a small change in ring face and groove geometry can significantly affect the lubrication characteristics and ring axial motion. This in turn can cause to change inter-ring pressure, blow-by and oil consumption in an engine. Therefore, by predicting the wear of piston ring face, ring groove and cylinder bore altogether, the changed ring end gap and the changed volume of gas reservoir can be calculated. Then the excessive oil consumption can be predicted. Being based on the calculation of gas flow amount by the theory of piston ring dynamics and gas flow, and the calculation of oil film thickness and friction force by the analysis of piston ring lubrication, the calculation theory of oil amount through top ring gap into combustion chamber will be set. This is estimated as engine oil consumption. Furthermore, the wear theories of ring, groove and cylinder bore are included. Then the each amount of wear is to be obtained. The changed oil consumption caused by the new end gap and the new volume of oil reservoir around second land, can be calculated at some engine running interval. Meanwhile, the wear amount and oil consumption occurred during engine durability cycle are compared with the calculated values. Next, the calculated amount of oil consumption and wear are compared with the guideline of each part's wear and oil consumption. So, the timing of part repair and engine life cycle can be predicted in advance without performing engine durability test. The wear data of rings and grooves are obtained from three engines before and after engine durability test. The calculated wear data of each part are turn out to be at the lower bound of aver-aged test values or a little below.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 춘계학술대회
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• pp.281-284
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• 2011

최근 유사석유제품 판매와 정량주유를 하지 않는 주유소로 인해 많은 운전자들이 피해를 입고 있고, 이러한 현상들이 점점 증가하여 앞으로 그 피해는 더 늘어날 전망이다. 유사석유제품을 사용함으로써 발생하는 피해는 연료계통의 윤활작용 및 자가 청정기능 문제, 부품의 조기 노후화 및 연료계통의 불순물 누적, 정품 휘발유와의 연소속도 차이로 인한 엔진의 부담 가중, 배기가스의 유독성물질 배출, 엔진오일과 확인되지 않은 화학적 반응 등이 발생하게 되는 문제점이 있다. 이러한 피해를 예방하기 위해 OBD-II 프로토콜로 자동차의 주행 내부정보를 받아 유사석유제품과 정량주유를 측정하고자 한다. 본 논문에서는 WinCe 기반의 개발보드를 이용하여 WiFi 통신을 지원하는 OBD-II 스캐너를 통해 주행 내부정보를 받아와서 현재 차량의 유사석유제품판별 시스템과 정량주유 시스템을 구현하였다.

• Tribology and Lubricants
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• 제22권3호
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• pp.131-136
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• 2006

Cylinder bore wear may not be a problem in most current automotive engines. However, a small change in cylinder bore diameter can significantly affect the lubrication characteristics and ring axial motion. This in turn can cause to change inter-ring pressure, blow-by and oil consumption in an engine. Therefore, by predicting the wear of piston ring face, ring groove and cylinder bore altogether, the changed ring end gap and the changed volume of gas reservoir can be calculated. Then the excessive oil consumption can be predicted. Being based on the calculation of gas flow amount by the theory of piston ring dynamics and gas flow, and the calculation of oil film thickness and friction force by the analysis of piston ring lubrication, the calculation theory of oil amount through top ring gap into combustion chamber will be set. This is estimated as engine oil consumption. Furthermore, the wear theories of ring, groove and cylinder bore are included. Then the each amount of wear is to be obtained. The changed oil consumption caused by the new end gap and the new volume of oil reservoir around second land, can be calculated at some engine running interval. Meanwhile, the wear amount and oil consumption occurred during engine durability cycle are compared with the calculated values. Next, the calculated amount of oil consumption and wear are compared with the guideline of each pare0s wear and oil consumption. So, the timing of part repair and engine life cycle can be predicted in advance without performing engine durability test. The wear data of cylinder bore diameter are obtained from three engines before and after engine durability test. The calculated wear data of cylinder bore diameter are turn out to be twice of the lower bound of averaged test values at TDC and the lower bound at BDC.

• 생약학회지
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• 제4권2호
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• pp.71-74
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• 1973

The contents of volatile oil and camphor in the oil of Artemisia messer-schmidtiana $B_{ESSER}$ var. viridis $B_{ESSER}$ f. typica $N_{AKAI}$ and Artemisia asiatica $N_{AKAI}$ which were known to be effective as antibacterial, antifungal and antineoplastic agents by screening experimentation, were determined quantatively by gas chromatography. The volatile oil contents of Artemisia messer-schmidtiana $B_{ESSER}$ var. viridis $B_{ESSER}$ f. typica $N_{AKAI}$ and Artemisia asiatica $N_{AKAI}$ are 0.17% and 0.19%, and the camphor contents are 8.51% and 1.46%, respectively.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권12호
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• pp.546-552
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• 2005

In this paper, a present condition with gas-in-oil diagnosis which used to condition analysis for oil insulated transformer is investigated and reason why hydrogen used to basic diagnosis for the transformer is described. This paper gives an overview of background knowledge that should to consider as moisture detecting of oil immersed paper and how could we approach to life expectancy of oil insulated transformer through detecting furfural compound.

• International Journal of Fluid Machinery and Systems
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• 제8권1호
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• pp.23-35
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• 2015

This paper presents the rotordynamic performance measurement of oil-free turbocharger (TC) supported on gas foil bearings (GFBs) for 2 liter class diesel vehicles and comparison to floating ring bearings (FRBs). Oil-free TC was designed and developed via the rotordynamic analyses using dynamic force coefficients from GFB analyses. The rotordynamics and performance of the oil-free TC was measured up to 85 krpm while being driven by a diesel vehicle engine, and compared to a commercial oil-lubricated TC supported on FRBs. The test results showed that the GFBs increased the rotor speed by ~ 20% at engine speeds of 1,500 rpm and 1,750 rpm, yielding the reduction of turbine input energy by more than 400 W. Incidentally, an external shock test on the oil-free TC casing was conducted at the rotor speed of 60 krpm, and showed a good capability of vibration damping due to the well-known dry friction mechanism of the GFBs.

• 한국식품영양과학회지
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• 제6권1호
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• pp.49-53
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• 1977

시판(市販) 고가(高價)의 기름에 저렴(低廉)한 기름을 혼입(混入)시키는 일이 흔히 일어나므로 이것을 쉽게 검색(檢索)하기 위한 방편(方便)으로 각 식용유(食用油)의 지방산조성(脂肪酸組成)을 gas chromatography 법(法)에 의해서 조성비(組成比)를 조사(調査)하였으며 이들 지방산(脂肪酸)의 조성(組成)을 보면 참기름은 myristic, palmitic, stearic, linoleic acid와 미량(微量)의 linolenic acid로, 미강유(米糠油)와 대두유(大豆油)는 myristic, palmitic, stearic, oleic, linoleic 및 linoleic acid, 들기름은 palmitic, stearic, oleic, linoleic, linolenic acid, 해바라기 기름은 palmitic, stearic, oleic acid 및 linoleic acid로 이루어져 있다. 이상의 결과로 볼 때 참기름에도 linolenic acid가 극미량(極微量) 밖에 존재하지 않으므로 이것이 풍부한 타(他)의 기름이 혼입(混入)되었을 경우 쉽게 검출(檢出)할 수 있을 것이다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1996년도 제24회 춘계학술대회
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• pp.86-93
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• 1996

The lubrication characteristics of high-speed ball bearings has been investigated empirically using 45mm bore split inner ring ball bearings employed in small industrial gas turbine engines with oil-jet lubrication method. For the close structural simulation, experiments carried out with bearing mounting supports of real engines, such as bearing housings and oil nozzle assemblies with squeeze film dampers. Thus the results of tests can be directly applied to the design and the development of gas turbine engines. Testing was done by varying operating speeds, axial load on bearings, and lubricant flowrates. During testing, the temperature of bearing at outer-ring face, the power consumption of the driving motor, and the rotating resistance of the bearing were measured. From this study, the representative factors for lubrication characteristics at high speed was found, and the most important one was not operating speed but axial load up to 1.95 million dmN speed and 303 kgf axial load. Furthermore, the detailed variation of the rotational resistance of the bearing could be visualized by measuring the change of the radial load under the bearing supports. The rotational resistance consists of the frictional resistance and the bearing-cavity oil resistance.