• Journal of Environmental Science International
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• v.15 no.5
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• pp.397-403
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• 2006

Compositional characteristics and origin of polycyclic aromatic hydrocarbons(PAHs), which should be strongly regulated for environmental protection in the crude oils and petroleum products, have been investigated by gas chromatography-mass spectrometry(GC/MS). In the crude oils analyzed, two-rings compound(naphthalene) of PAHs was detected around $72.3\sim93.5%$, but five- or six-rings compound of PAHs was not detected. In the crude oils analyzed, the molecular ratio indices of Phe/Ant(phenanthrene/anthracene)>15, Fla/Pyr(fluoranthene/pyrene)<1, BaA/Chr(benzo (a)anthracene/chrysene)$\leq0.4$ could be effectively applied, and we found that the origin of PAHs was petrogenic sources. Total PAHs concentrations in the crude oils were increased with increasing API gravity and with decreasing sulfur contents of the analyzed crude oils. Five- or six-rings compound of PAHs were not included in ail petroleum products except bunker-C. Furthermore, the molecular ratio indices of Phe/Ant(phenanthrene/anthracene) vs. Fla/Pyr(fluoranthene/pyrene) could be effectively applied as the standard for the PAHs contamination criterion at the other Korean areas.

• Physical Therapy Korea
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• v.9 no.4
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• pp.13-35
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• 2002

Lesch-Nyhan 증후근(LNS)은 hypoxanthine guanine phosphoribosyle transferase(HGPRT) 효소를 암호화 하는 X 염색체가 불완전해서 일어나는 유전적인 추제외로계(또는 기저핵)의 드문 병변이다. 출생시 LNS 유아는 정상적인 운동발달이 관찰되어진다. LNS에게서 현저하게 진단적인 특징으로 보여지는 운동심리적 행동인 self-mutilating 행위는 4살 이후에나 나타난다. LNS 아이들은 오히려 초기에 Rett's 증후근, 뇌성마비, 자폐, 다운증후근과 유사한 운동행위를 보인다. 그래서 LNS 아이들은 앞에 기술한 신경학적 장애로 오진을 받을 수가 있다. 오진으로 인해 초기에 적절한 치료를 받지 못한다면 LNS는 결과적으로 합병증(신장부전)과 self-mutilating 행위로 인하여 치명적일 수가 있다. 그러므로, 이 연구의 목적은 LNS 평가 동안 더 나은 진단을 하도록 하기 위하여 LNS와 관련된 기능부전에 대한 지식을 임상가들에게 제공하고자 함이었다. 연구 대상자는 10살인 2명의 쌍둥이 남아이었으며 실험은 뻗기 과제 수행(reaching task)시 움직임 특성을 보기 위하여 운동형상학적과 비디오 분석을 사용하였다. 기술통계로 분석 결과 움직임 시간과 단위가 증가됨을 보였고 사지의 분절적 움직임이 협응되지 않음을 보였다. ballistic과 jerky 움직임 양상은 dysmetric과 비긴장성 운동 행위에서 우세하였다. LNS은 추체로계 운동 장애 (과근긴장도나 저긴장도) 와 추체외로계의 운동 장애(dystonia와 choreoathetosis)의 혼합된 형태를 보였다. 결론으로 이 연구는 운동발달 장애를 가진 아이들을 치료하고자 할 때 임상가들한테 LNS 아이들의 움직임 장애의 다른 진단적 특징을 알아야 한다는 것을 제시하고자 한다.

• KSBB Journal
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• v.13 no.2
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• pp.209-213
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• 1998

The characteristics of de-emulsification of pertroleum emulsion by Nocardia amarae were investigated. Insoluble medium containing n-hexadecane was more effective than soluble medium in de-emulsification of emulsion containing diesel and bunker C as the organic phase. Emulsion made by the addition of xanthan or bioemulsifier was de-emulsified by N. amarae, and longer culture age was effective. In low viscosity range, organic phase with longer carbon chain was more effective. The contact, angle between bacterial film and water droplet in air increased from 16 degree for 4 day culture age to 26 degree for 15 day. The contact angle between bacterial film and water droplet in kerosene, n-heyxane or n-hexadecane also increased to greater than 100 degree after 3 day culture age. The hydrophobicity of bactgerial film increased according to the culture age.

• Tribology and Lubricants
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• v.28 no.5
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• pp.233-239
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• 2012

The engine of a large ship operates under wet conditions using a fuel such as bunker C oil, which includes sulfur and many impurities. A cylinder liner made of cast iron is very susceptible to damage such as scuffing on the surface. This scuffing can reliably be attributed to the destruction of the oil film and the corrosion wear caused by water and sulfur included in the fuel, along with abrasion impurities and poor lubricants. In this study, a reciprocating friction and wear test was carried out with a cast iron specimen, which was used to simulate an engine cylinder in a corrosive environment. Base-oil and stirred oil containing distilled water, NaCl solution, and dilute sulfuric acid were used as lubricants. The friction surface was analyzed using a microscope and EDAX, and the friction coefficient was measured using a load-cell under each experimental condition. We then attempted to investigate the damage to the cylinder liner using the results.

• Journal of Korea Port Economic Association
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• v.31 no.2
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• pp.55-67
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• 2015

This study analyzes the relationship between shipping profit and market return in the tramp trade from January 2000 to October 2014. First, we carry out the causality test and find a causal relationship between the studied variables. Second, the estimates from the Johansen cointegration test show that shipping profit is cointegrated with market return, which implies that a long-run relationship exists among the variables. The empirical results thus imply that shipping firms need diverse risk management strategies.

• Journal of Sensor Science and Technology
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• v.31 no.4
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• pp.266-270
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• 2022

Owing to the rising volume of seaborne trade, oil spills damage the marine environment for over 250 yearly. Thus, various analysis methods such as the Fourier-transform infrared (FTIR), Raman spectroscope, and gas chromatography are used to monitor oil spills at sea, but these methods are expensive. Recently, to reduce operational costs, an underwater fluorometer was adopted. However, this approach is not ideal for the remote sensing of oil spills because the device gets submerged in the sea. In this study, we have designed and developed a monitoring system that uses ultraviolet fluorescence to detect spilled oil or water from a distance, as well as proposed an analyzing method defining based on water Raman signal and QF535. Each fluorescence spectrum of water, oil (crude oil), and Bunker A was obtained using the system, and was calculated and analyzed from the spectrum individually. Based on the results of the analysis, we could successfully identity water and oil at a long distance.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.107-110
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• 2013

Recently, Korea parliament legislated the Low Carbon Green Growth Act (April, 2012) and approved a bill (May, 2012) to start carbon emission trading system in 2015. It means that for the first time, government would regulate the amounts of carbon emission in private entities, and private entities should attain predefined emission reduction goals by implementing clean development mechanism (CDM) project or buy the Certified Emission Reductions (CERs) from the trading market to avoid penalty. Under these circumstances, it is not easy for them to determine when or how to implement the CDM project because the governmental energy policies about the level of governmental subsidies, periods for free emission allocation, etc. are still under discussion and the future price of the CERs is quite uncertain. Thus, this study presents a real-option based model to assess the financial viability of the CDM project which switches bunker-C oil to liquefied natural gas (LNG). The proposed model is expected to assist private entities in establishing the investment strategy for CDM project under uncertain government energy policies.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.600-604
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• 2003

This study pointed at isolation of bunker-C oil degrading bacteria and then estimation of it's degrading capability in environmental conditions. Degradation ratio of the excellent isolate was appeared to 40.5% and 44.7% when the oil was treated to 1% and 5%, respectively. The isolate was identified to Acinetobater calcoaceticus SEBCM. In pH test, high degrading effect was appeared to about 73% at pH 6 and pH 7, and low degrading ratio was 37% at pH 4. Its growth condition at temperature has not large variation in $15^{\circ}C\;{\sim}30^{\circ}C$, Quantity of nitrogen for it's good growth was ranged of $0.5\;g/L{\sim}2\;g/L$. As these results, we realized that this isolate have good activity when treated to $15\;{\sim}30^{\circ}C$ of temperature and $6{\sim}7$ of pH.

• Journal of Korean Society for Atmospheric Environment
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• v.5 no.1
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• pp.68-78
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• 1989

The heavy metal of suspended particulates with human health has long been studied in environmental interest concerned. This study was intended to identify harmful heavy metals of the ambient air borne dusts which were related with the respirable sizes in the aerodynamics. Two sampling sites were selected comparatively; one was in the Shinchon area, which is the commercial district with heavy traffic and the other site was in the Bulgwang area which is residential area. The supended particulates were sampled by high volume air sample with 6 cascade impactor stages. The heavy metals in terms of As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V and Zn were determined by stomic absorption spectrometry or inductively coupled plasma emission spectrometry. The samples weretaken bimothly for seven consecutive days from May 1987 to March 1988. The annual average concentration of the respirable suspended dust of which diameter is less than 10$\mum$ was 152.59 $\mug/m^3$ of the Shinchon air samples; the respirable dust was equivalent to approximately 85% of the total suspended particulates. The annual average concentration of the respirable suspended dust of the Bulgwang air samples was 112.56 $\mug/m^3$; that was approximately 86% of the total suspended particulates. The concentration of heavy metals was investigated in relation to the particle size. The concentration of Cr, Fe, Mn and V were tended to be much more in the coarse particles than in the fine particles. Cd and Pb in the fine particles were more than in the coarse particles. In the partial correlation coefficients; in the Shinchon area, high correlations among Fe, Se and Mn were determined; it is assumed that those sources would be originated from coal, gasolineand diesel. In Bulgwang area, would be high correlation among Fe, Se, Hg and Mn considered to be originated from coal, Bunker-C and heavy oil as well. From the above results, the hazardous heavy merals in air should be measured and controlled in originally their sources.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.4
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• pp.263-267
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• 2013

In this research, a novel optical measuring methodology for the measurement of oil thickness in seawater is suggested by evaluating the light absorption which is occurred in the process of penetrating through oil layer on seawater. Laser having monochromatic wave is used as a light source and photodiode which can convert the intensity of the light into an electrical signal is applied to measure the intensity of the penetrating light through the oil-water mixtures. In the experiment, bunker C and lubricating oil are used, and three different lasers having different wavelengths are applied and compared for the selection of an optimal light source. As a result, it is observed that in the case of blue laser, the intensity of the light on the optical sensor decreases with an increase in the oil thickness. Through this relation, both the presence of oil and the thickness of oil can be determined.