• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.26 no.10
• /
• pp.1472-1479
• /
• 2002

Environmental protection on the ocean has been interested and nowadays the International Maritime Organization(IMO) has advanced on the prevention of air pollution from ships. This study presents the emission characteristics of 4 stroke marine diesel engines in E3 cycle (propulsion application) and D2 cycle (generation application). Also the effects of important operating parameters in terms of intake air pressure and temperature, and maximum combustion pressure on the specific emissions are described. Emissions measurement and calculation are processed according to IMO Technical Code. The results show that NOx emission level in E3 cycle is higher than that in D2 cycle due to lower engine speed at low load and the maximum combustion pressure by fuel injection timing control and intake air temperature has strong influence on NOx emission production. And CO, HC emissions are not affected by maximum combustion pressure and intake air pressure and temperature.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2005.11a
• /
• pp.230-231
• /
• 2005

As environmental problems are important, automotive industries are developing various techniques to prevent air pollution. One of these is Positive Crankcase Ventilation (PCV) system. It removes blowby gas which includes about 30% hydrocarbon of total generated quantity. In this system, a PCV valve is attached in a manifold suction tube to control the flow rate of blowby gas which generates differently according to various operating conditions of an automotive engine. As this valve is very important, designers are feeling to design it because of both small size and high velocity. For this reason, we numerically investigated to understand both spool dynamic motion and internal fluid flow characteristics. As the results, spool dynamic characteristics, i.e. displacement, velocity, acting force, increase in direct proportion to the magnitude of differential pressure and indicate periodic oscillating motions. And, the velocity at the orifice region decreases according to the increase of differential pressure because of energy loss which is caused by the sudden decrease of flow area at the orifice region and the increase of flow volume in the front of spool head. Finally, the mass flow rate at the outlet decreases with the increase of spool displacement. We expect that PCV valve designers can easily understand fluid flow inside a PCV valve with our visual information for their help.

• Korean Journal of Ecology and Environment
• /
• v.40 no.4
• /
• pp.489-494
• /
• 2007

Transcriptional modulation of metallothionein (MT) during acute metal exposures (cadmium, copper or zinc) was examined in fry of Hemibarbus mylodon, a threatened fish species in Korean peninsula. Viability of H. mylodon fry was most affected by copper exposure (up to 79% of mortality at 1 ppm for 48 hours) and considerably by cadmium exposure (21 to 54% of mortality). On the other hand, Zn showed the least adverse effect on the viability (0 to 13% of mortality) of this species. Based on the semi-quantitative RT-PCR analysis, the stimulation of MT mRNA in response to metal exposures followed generally in a dose-dependent fashion where cadmium was the most potent inducer for the induction of MT transcripts in fry (up to more than 5-fold) while the lowest response was observed in zinc-exposed group (2-fold at maximum). From the exposure using environmentally realistic doses of cadmium (0 to 0.05 ppm for 24 hours), MT expression at mRNA level was also sensitively modulated toward upregulation up to more than 3-fold as relative to non-exposed control. Results from the present study would be a good basis for understanding the adaptive capacity and stress physiology of this endangered fish species during metal pollution.

• Journal of Life Science
• /
• v.9 no.3
• /
• pp.282-288
• /
• 1999

This study was designed as a part of efforts to investigate the biochemical pollutant markers for diagnosis of marine pollutions by changes in cholinesterase activity of the mussel (Mytilus coruscus) in South Sea of Korea. Acetylcholinesterase (AChE) activities in muscle of cultured mussels in South Sea were remarkably lower (20∼41%, respectively) than those of wild mussel in Pohang(control) of East Sea. Acetylcholine (Ach) activities in muscle of cultured mussels in South Sea were remarkably lower (15∼30%, respectively) than those of wild mussel in Pohang of East Sea. Monoamineoxidase (MAO-B) activities in muscle of cultured mussels in South Sea were significantly 2∼19% higher than those of wild mussel in Pohang of East Sea. It suggests that AChE, ACh and MAO-B activities in muscle of cultured mussels of South Sea may be used as the most effective mean in a biochemical markers for early warning of environmental damages caused by organophosphorus pesticides.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.47 no.4
• /
• pp.428-434
• /
• 2011

To establish a vessel safety management system for improving the safety of vessel's traffic and preventing vessel's traffic accidents, the state of marine traffic in the Busan South Port was investigated and analyzed as preliminary survey of the countermeasures. As a result of the study, there are 1,158 vessels in a day, 48 vessels in an hour, and the maximum traffic is about 118 vessels between 16:00 and 17:00 hours everyday, which requires to establish and operate a traffic control system necessarily for ensuring vessel's traffic safety. Furthermore, passages of tanker, passenger ship, cargo vessel and government vessel showed to sail along main traffic lane to be obtained enough sea depth at the survey area. However, passages of fishing vessel and launch showed to sail freely at all survey area owing to outstanding maneuverability and a shallow draft. Some vessels of launch sailed along main traffic lane, but other vessels crossed to sail it. The passages to cross main traffic lane is higher the risk of collision. Therefore, safety measures are urgently needed for the operation of the Busan South Port management system and the prevention of marine pollution.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.18 no.1
• /
• pp.36-44
• /
• 2015

The spatial and temporal distribution of dissolved trace metals has been studied to identify trends in space and time and to evaluate the pollution status in a semi-closed bay (Gohyun bay), Korea. Surface seawater samples were collected over four seasons at 18 stations in the bay between 2003 and 2004 and once at 7 stations around a large shipyard in May 2004. The concentration of Cd, Co, Cu, Ni, Pb, and Zn in seawater in February and May were highly variable in space, showing the higher value relative to other season. Those metals concentrations were decreased from inner-to outer-stations. In around the shipyard, Cu, Pb and Zn showed the higher variability depending on time. Cu and Zn concentrations at the sites around the shipyard had 2 times higher values compared with the average of inner stations in Gohyun bay. The very high correlations between salinity and either Cu and Zn has been showed. Especially, there was a significant relationship between Cu and Zn. We recognize that the shipyard is major source of Cu and Zn in seawater. Therefore, marine environment management policy such as the prevention and control of heavy metal input from a shipyard is required.

• Journal of Environmental Science International
• /
• v.22 no.7
• /
• pp.787-799
• /
• 2013

The aim of this study was to investigate the accumulation of metallic elements and the control effect of marine pollution caused by ocean dumping in the sediments at a waste disposal area in the Yellow Sea. In July 2009, concentrations of organic matter and metallic elements (Al, Fe, As, Cd, Cr, Co, Hg, Ni, Mn, Pb, and Zn) were measured in surface sediments at the site. The ignition loss (IL) in the surface sediments showed a mean value of 15.4%, about 1.5 times higher than the mean value of the sediments in the coastal areas of Korea. The chemical oxygen demand (COD) at some disposal sites exceeded 20 mg $O_2/g{\cdot}dry$, which signifies the initial concentration of marine sediment pollutants in Japan. The disposal sites contain higher concentrations of Cr, Cu and Zn than the sediments of bays and estuaries that might be contaminated. The magnitude of both metal enrichment factors (EF) and adverse biological effects suggest that pollution with Cr and Ni occurred due to the dumping of waste in the study area. In addition, the geoaccumulation index (Igeo) showed that the surface sediments were moderately contaminated. By the mid-2000s, when the amount of waste dumped at this site was the highest, the concentration of metallic elements was higher than ever recorded. On the other hand, in 2008-09, the need for environmental management was relatively low compare with the peak. As a result, the quality of marine sediment has been enhanced, considering the effect of waste reduction and natural dilution in the disposal area.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.5 no.1
• /
• pp.68-75
• /
• 2002

This study were observed to the conditions of organic pollution applying to tile environmental assessments based on macrobenthos around the raft culture ground which became an issue by organic matter input in Jinhae Bay. Three stations, mussel farm, oyster farm and the control station on which rarely culture activities were fixed and have analyzed to the sediment characteristics and macrobenthic communities. Muddy substrates between 6.0 and 6.60 on mean grain size have prevailed to the bottom layer in all stations. The highest organic matter content of 2.8% was observed to the mussel farm while the lowest one of 1.5% was recorded on the control area. As a total, 79 species from seven phyla were identified. Comparing to shell farms, the control station have composed to more diversified community structure. In the mussel and the oyster farm, opportunistic species, living in high organic contents area, Lumbrineris longifolia, Heteromastus. filiformis in polychaetes and Corophium sinense in amphipod were dominated. As results on environmental assessment, in spite of changing to the species composition and densities seasonally, the mussel farm have recorded only to moderately polluted condition.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.6
• /
• pp.694-700
• /
• 2018

Korea has disposed of medium and low level radioactive waste generated by operating nuclear power plants permanently through the radioactive waste repository located in Gyeongju. However, the maritime transport of radioactive waste is exposed to the risk of marine accidents, and it will be necessary to introduce a system to secure safety from the viewpoint of the function and role of the Korea Coast Guard. Especially, Korea is affected by large-scale marine accidents, such as the Hebei Spirit or Sewol accidents. From this point of view, we analyzed the current status of Korea radioactive waste shipping and examined the response systems of major foreign countries. As a result of examining major cases of accidents, we have operated an Emergency Towing Vessel (ETV) fleet centering on European countries in order to respond urgently to marine casualties that may have social, regional and international effects, such as accidents of similar nuclear material carriers and dangerous cargo ships. It proves a partial effect. Based on this, we propose the introduction of the Korean ETV System. In other words, it is necessary to respond to large-scale marine accidents that could lead to enormous environmental, property, and personal damage, such as marine accidents involving nuclear material ships, large oil tankers, and large passenger ships. For this, it seems necessary to introduce Korea ETV, which can carry out emergency towing, oil pollution control function, large - scale rescue equipment and manpower. This will lead to the enhancement of the Korea Coast Guard response to marine accidents, and will not miss the golden time of the initial response to the national disaster, which will help protect precious people, property and the environment.

• Journal of Ocean Engineering and Technology
• /
• v.27 no.3
• /
• pp.8-14
• /
• 2013

Although there are various factors that threaten the security of ships, one of the most harmful is corrosion. It is not easy to find corroding areas and the status of corrosion, even though corrosion causes serious problems such as submergence and marine pollution as a result of leaking oil and polluted water. To monitor the corrosion of ships, non-destructive inspection, weight loss coupons, electrical resistance, linear polarization resistance, zero resistance ammeter, and electrochemical impedance spectroscopy have been developed. However, these methods require much time to detect corrosion, and most are not appropriate for real time monitoring. Coating, sacrificial anode, and impressed current cathodic protection (ICCP) methods have been developed to control corrosion. The ICCP and sacrificial anode methods are the most popular ways to prevent ship corrosion. However, ICCP is only appropriate for the outside of a ship and cannot be used for complex structures such as ballast tanks because these are composed of many separate chambers. Sacrificial anodes have to be replaced periodically. This paper proposes an integrated corrosion monitoring and control system (ICMCS) that can detect corrosion in real time and is appropriate for complex structures such as ballast tanks. Because the system uses titanium for an anode, exhausted anodes do not need to be replaced.