• Journal of Mechanical Science and Technology
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• 제16권4호
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• pp.549-556
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• 2002

An investigation on the fully developed heat transfer and friction factor characteristics has been made in rectangular ducts with one-side roughened by five different shapes. The effects of rib shape geometries as well as Reynolds numbers are examined. The rib height-to-duct hydraulic diameter, pitch-to-height ratio, and aspect ratio of channel width to height are fixed at e/De=0.0476, P/e=8, and W/H=2.33, respectively. To understand the characteristics of heat transfer enhancements, the friction factors are also measured. The data indicates that the triangular type rib has a substantially higher heat transfer performance than any other ones.

• Journal of Advanced Marine Engineering and Technology
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• 제22권5호
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• pp.693-701
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• 1998

This study presents result of comparison between two other numerical method method of char-acteristics(MOC) and Lax-Wendroff method(LWM) applied at wave action analysis of intake and exhaust pipe in terms of calculated pressure velocity and emitted noise in the time and the fre-quency domain by means of fast Fourier transform analysis. Particularly FCT(Flux Corrected Transport)scheme is appended to LWM to protest unaceptable overshoots occurring near discon-tinuity. The final conclusion of this study is that MOC should be replaced by a second order finite difference approach because of larger contributions due to high frequency components than the results from the method of characteristics. Clear benefits we can get by change are faster calcula-tion higher accuracy conservation of mass and consistent calculation method.

• 수산해양교육연구
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• 제13권2호
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• pp.168-177
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• 2001

The flow pattern and water mass structure in the Chungmu channel were investigated using the field observations during June and July, 2001. The currents in the channel may be regarded as a hydraulic current decided by difference of tide levels between two sides in the channel. The strongest current in the channel occurs around in high water and low water. The coefficient C to be determined the characteristics of velocity in the channel was obtained from an equation, $u=C{\sqrt{2gh}}$ and ranges from 0.37 to 0.65 in the Chungmu Channel at the spring tide and from 0.23 to 0.37 at the neap tide. Eastward tidal transport is usually larger than that of westward transport in Chungmu the Channel. Sea water exchange rates are 39.2% in spring tide and 20.5% in neap tide respectively. The water mass structure in the channel is changed by the speed of the tidal current. The water mass is well mixed at the high water when the current is strong and is stratified at slack water when the current is weak.

• 수산해양교육연구
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• 제28권6호
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• pp.1772-1780
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• 2016

NCS development for the treatment of waste oils from ship was carried out through steps such as analysis on characteristics, development of competency standard, utilizing package, and validation of industry sites. The results were as follows. Firstly, duty competency was classified as levels from 2 to 6. Educational training institutions were followed by 75 graduate schools, 73 universities, 54 colleges, and 37 high schools. Secondly, developed standards were consisted of duty and competency unit. The name of duty was the treatment of waste oils from ship and competency units were consisted of 8 items as classification of waste oils from ship, pickup and transport of waste oils from ship, warehousing of waste oils from ship to marine disposal company, transport of waste oils from ship to land, warehousing of waste oils from to disposal company, determination of disposal method and plant recycling treatment, and incineration treatment. 28 competency unit elements below 8 competency units were developed. Thirdly, utilizing package was developed into 3 areas of life-long career path, training criteria, and guidelines for exam according to national competency standards in order to develop development of labor's career and perform personal management such as hiring and promotion in industry sites.

• 한국환경과학회지
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• 제11권7호
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• pp.669-677
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• 2002

This study was conducted to investigate the characteristics of role of transport on aerosol concentration at Crate Lake, Oregon USA for 1988.3~1999. 5. The IMPROVE program is a cooperative measurement effort governed by a steering committee composed of representatives from USA federal and regional-state organizations. Also IMPROVE sampler is designed to obtain a complete signature of the composition of the airborne particles affecting visibility. According to 10-day backward isentropic trajectory analysis, the frequency of local, marine and Asian trajectory showed 33.1%(335 cases), 47%(478 cases), 5.2%(53 cases) respectively. The monthly variation of nss $SO_4^{2-}$, nss S, $NO_3^-$, K and C showed the double peak pattern, high in April~May and August~september and showed the lowest concentration in Winter. The other constituents concentration except for Cl$^{[-10]}$ , Na, Mg was high in local trajectory than marine trajectory. A ratio nss $SO_4^{2-}$ to $SO_4^{2-}$ was 90.5% in marine trajectory and 98% in local trajectory. It suggest that the aerosol in Crater Lake was effected by salt. The annual mean concentration of nss $SO_4^{2-}$ and nss S decreased but the springtime concentration increased.

• 한국ITS학회:학술대회논문집
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• 한국ITS학회 2004년도 제3회 정기총회 및 추계학술대회
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• pp.370-374
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• 2004

• 수산해양교육연구
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• 제25권2호
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• pp.448-457
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• 2013

The media is an effective means of preventing crime. It can be known to members of the media presiding over the most widely and rapidly. Because of this, the mass media is a good way to prevent such crime. Related to general crime, marine crime will have unique characteristics and about Crimes reported by the media, it is also true. The results of this study are as follows. Firstly, it is required that the more accurate present article must be published and reported. Secondly, for more accurate presentation of measure, there is a need to enhance professional training for reporters. Thirdly, the marine weather report is the most important political purpose of considering marine crime prevention. Forthly, marine crime is likely to be a lack of evidence. Therefore, in order to supplement the lack of evidence maritime security agency should be utilized for a news source.qualification Fifthly, the need for regular inspection of the articles is requested. Sixthly, for judicial control maintenance of the media related laws should be strengthened. Finally, the arbitration institution for media rights should be established under the Korea Ministry of Land Infrastructure and Transport. This is practical action for marine crime prevention.

• Ocean Science Journal
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• 제41권4호
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• pp.291-299
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• 2006

Hydrographic surveys were carried out four times in the western channel of the Korea Strait in March and August 2003 and in June and November 2004. The bottom cold water, which was lower than $10^{\circ}C$, appeared in the channel trough except in March 2003. It flowed southwestward along the shelf of Korean coasts in August 2003 and in November 2004. The width and the maximum speed of the intrusion current were about 20 km and approximately $25\;cm\;s^{-1}$, respectively, off Ulsan, Korea. The volume transport of the bottom cold water was estimated 0.019 Sv ($Sv{\equiv}10^6\;m^3\;s^{-1}$) in August 2003 and 0.026 Sv in November 2004.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2000년도 International Symposium:on the Maritime Management Systems for Safer and Cleaner Seas in the New Millennium
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• pp.86-100
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• 2000

The author of this document is generally in charge of Port State Control affairs at the headquarters of Ministry of Transport, Japan. In this document, the necessity of Port State Control, the brief history of japanese Port State Control and the present system of Port State Control in Japan are introduced. Also, the newest output of Japanese Port State Control which is an annual statistic of 1999 is explained, subsequently the policy and strategy on Port State Control in Japan is introduced.

• 한국해양공학회지
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• 제23권2호
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• pp.47-52
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• 2009

A Lagrangian particle tracking model coupled with the Princeton Ocean Model were used to estimate the average residence time of coastal water in Masan Bay, Korea. Our interest in quantifying the transport time scales in Masan Bay was stimulated by the search for a mechanistic understanding of this spatial variability, which is consistent with the concept of spatially variable transport time scales. Tidal simulation was calibrated through a comparison with the results of semi-diurnal current and water elevation measured at the tidal stations of Masan, Gadeokdo. In the model simulations, particles were released in eight cases, including slack before ebb, peak ebb, slack before flood, and peak flood, during both spring and neap tides. The averaged values obtained from the particle release simulations were used for the average residence times of the coastal water in Masan Bay. The average residence times for the southeastern parts of Somodo and the Samho River, Masan Bay were estimated to be about 20~50days and 70~80days, respectively. The spatial difference for the average residence time was controlled by the tidal currents and distance from the mouth of the bay. Our results might provide useful for understanding the transport and behavior of coastal water in a bay and might be used to estimate the dissimilative capacity for environmental assessment.