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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Marine Engineering
Journal Basic Information
Journal DOI :
Korean Society of Marine Engineers
Editor in Chief :
Volume & Issues
Volume 38, Issue 10 - Dec 2014
Volume 38, Issue 9 - Nov 2014
Volume 38, Issue 8 - Oct 2014
Volume 38, Issue 7 - Sep 2014
Volume 38, Issue 6 - Jul 2014
Volume 38, Issue 5 - Jun 2014
Volume 38, Issue 4 - May 2014
Volume 38, Issue 3 - Mar 2014
Volume 38, Issue 2 - Feb 2014
Volume 38, Issue 1 - Jan 2014
Selecting the target year
Optimum seat design for the quadruple offset butterfly valve by analysis of variance with orthogonal array
Lee, Sang-Beom ; Lee, Dong-Myung ;
Journal of the Korean Society of Marine Engineering, volume 38, issue 8, 2014, Pages 961~967
DOI : 10.5916/jkosme.2014.38.8.961
In onshore and offshore plant engineering, a broad use of pipe system have been achieved and accordingly related technologies has been developed especially in the field of flow control valves. The aim of this study is to suggest the quadruple offset butterfly valve for bi-directional applications which show equivalent operating torque characteristics of the triple offset butterfly valve. Seat design parameters for the quadruple offset butterfly valve are determined by the proposed method utilizing both ANOVA (analysis of variance) and the orthogonal array. Through additive model considering the effect of design parameters on seating torque, mean estimation is performed and thus its optimization results are verified by design of experiment results. The insight obtained from the present study is beneficial for valve design engineers to develop reliable and integrated design of the quadruple offset butterfly valve.
Investigation on electrochemical performance of Al anode material for marine growth prevention system
Kim, Seong-Jong ; Jang, Seok-Ki ; Han, Min-Su ; Lee, Seung-Jun ;
Journal of the Korean Society of Marine Engineering, volume 38, issue 8, 2014, Pages 968~973
DOI : 10.5916/jkosme.2014.38.8.968
Aluminum anode of marine growth prevention system for ship is installed in seachest or sea water strainer. The Al anode is connected to a control panel that feeds a current to the anode. The dissolved ions produced by the anode are transferred in sea water, spreads through the sea water pipe system and creates a protective film in the pipelines. Thereby, corrosion in pipeline system significantly is reduced. In application on condition as a steel ship, the big accident can be caused by the corrosion. Accordingly, in this research, we evaluated influence of applied current and flow velocity on electrochemical characteristics of Al anode for marine growth prevention system (MGPS). Based on the results of the erosion-cavitation experiments, cavitation rate increased greatly until 120 min. of the experimental time and decreased a little at the point of 180 min. where pit grew and merging occurred but showed a tendency of steadily increasing consumption rates. Based on the results of the Tafel analysis, compared to static states, corrosion current densities show a rapidly increasing tendency when flow occurred.
Effects of rotation speed and time in potentiostatic experiment in seawater for 5083-H116 Al alloy
Lee, Seung-Jun ; Han, Min-Su ; Jang, Seok-Ki ; Kim, Seong-Jong ;
Journal of the Korean Society of Marine Engineering, volume 38, issue 8, 2014, Pages 974~980
DOI : 10.5916/jkosme.2014.38.8.974
Aluminum acts as sacrificial anode and corrosion protection with Al2O3 formation. If the same current on material for Al ships with steel ships supplies, the more hydrogen would be occurred, that result is bring about over-protection. For this reason, the damage by hydrogen embrittlement leads to the serious accident. In this study, we evaluate electrochemical behavior with rotation speed of 5083-H116 Al alloy material for Al ship in seawater. To examine the electrochemical characteristics with rotation speed and its effects on performance, experiments were conducted at four rotation speed. Results of experiments, the corrosion current density and damage were increased by applying the rotation speed compared to static state.
Characteristics of the plume formed by the buoyant discharges from the river
Kim, Ki-Cheol ; Kim, Sung-Bo ;
Journal of the Korean Society of Marine Engineering, volume 38, issue 8, 2014, Pages 981~994
DOI : 10.5916/jkosme.2014.38.8.981
Density currents formed by buoyancy discharges from rivers are numerically studied using non-dimensional two layer model including Coriolis acceleration, bottom stress, interfacial friction. Some typical numbers such as Froude number, densimetric Froude number and Kelvin number are obtained and some characteristic scales are defined as a result of non-dimensionalization of the governing equations. Besides the Coriolis effect, the configurations of bottom topography, bottom friction coefficient and interfacial friction are found to significantly affect the propagation of the warm water plume. Frontal position can fastly propagate in the case of large density difference between the two layers and small interfacial friction. Left side boundary current is easily formed under the small interfacial friction. With large Kelvin number, both right and left side boundary currents are formed. Wave-like disturbances and eddies are easily formed under the high Froude number.
Design of an extremely miniaturized branch-line coupler
Kang, In Ho ; Li, Xi Qiang ;
Journal of the Korean Society of Marine Engineering, volume 38, issue 8, 2014, Pages 995~999
DOI : 10.5916/jkosme.2014.38.8.995
In this paper, a new size-reduction approach for branch-line coupler is introduced which uses parallel end-shorted coupled lines with lumped capacitors. The characteristic of the new design was analyzed using even-odd mode method, and simulated on HFSS before fabricated on the FR4 epoxy glass cloth copper-clad plat (CCL) PCB substrate at center frequency of 1 GHz. The electrical length of transmission line was reduced to 15 degrees, therefore the size of branch-line coupler was largely reduced approximately maintaining the same characteristic around the stable center frequency. The insertion loss of the branch-line coupler filter was -4.39 dB. The size of the overall hybrid is
. Measurements results were well agreed with the simulated ones.
Digital DC power supply for light accelerator
Kim, Yoon-Sik ;
Journal of the Korean Society of Marine Engineering, volume 38, issue 8, 2014, Pages 1000~1003
DOI : 10.5916/jkosme.2014.38.8.1000
There are 70 vertical and 70 horizontal correctors for Pohang Light Source. Until mid of 2000, power supplies for these correctors were based on 1990's technology, so the global orbit feedback system was not possible with poor 12 bit resolution. A new task force team was assembled to develop new power supplies with BESSY type DAC cards. After the project, two vertical correctors in each lattice were connected with new power supplies, and the global orbit feedback was available within the accuracy of 5 microns. However, this replacement was not enough to satisfy the beam stability requirement of 2 microns for PLS. We have launched another power supply design based on all digital technology. This attempt was completed within a year, and 80 units were assembled in house. Currently, the global orbit feedback system is running successfully with new digital power supplies and the compensation of chamber motion due to the thermal load by using digital displacement transducers attached on each BPMs.
An efficient metaheuristic for multi-level reliability optimization problem in electronic systems of the ship
Jang, Kil-Woong ; Kim, Jae-Hwan ;
Journal of the Korean Society of Marine Engineering, volume 38, issue 8, 2014, Pages 1004~1009
DOI : 10.5916/jkosme.2014.38.8.1004
The redundancy allocation problem has usually considered only the component redundancy at the lowest-level for the enhancement of system reliability. A system can be functionally decomposed into system, module, and component levels. Modular redundancy can be more effective than component redundancy at the lowest-level because in modular systems, duplicating a module composed of several components can be easier, and requires less time and skill. We consider a multi-level redundancy allocation problem in which all cases of redundancy for system, module, and component levels are considered. A tabu search of memory-based mechanisms that balances intensification with diversification via the short-term and long-term memory is proposed for its solution. To the best of our knowledge, this is the first attempt to use a tabu search for this problem. Our tabu search algorithm is compared with the previous genetic algorithm for the problem on the new composed test problems as well as the benchmark problems from the literature. Computational results show that the proposed method outstandingly outperforms the genetic algorithm for almost all test problems.
Ecotoxicological effects of ballast water effluent teated by an electrolytic method on marine environment
Kim, Tae Won ; Kim, Keun-Yong ; Shon, Myung-Baek ; Kim, Young-Soo ; Lee, Ji Hyun ; Moon, Chang Ho ; Son, Min Ho ;
Journal of the Korean Society of Marine Engineering, volume 38, issue 8, 2014, Pages 1010~1020
DOI : 10.5916/jkosme.2014.38.8.1010
Ballast water effluent treated by an electrolytic method contains reactive chlorine species and disinfection by-products (DBPs). In this study, we conducted whole effluent toxicity (WET) testing and ecological risk assessment (ERA) to investigate its ecotoxicological effects on marine environment. WET testing was carried out for three marine pelagic organisms, i.e., diatom Skeletonema costatum, rotifer Brachionus plicatilis and fish Paralichthys olivaceus. The biological toxicity test revealed that S. costatum was the only organism that showed apparent toxicity to the effluent; it showed no observed effect concentration (NOEC), lowest observable effect concentration (LOEC) and effect concentration of 50% (EC50) values of 12.5%, 25.0% and 83.3%, respectively, at brackish water condition. In contrast, it showed insignificant toxicity at seawater condition. B. plicatilis and P. olivaceus also showed no toxicities to the effluent at the both salinity conditions. Meanwhile, chemical analysis revealed that the ballast water effluent contained total residual oxidants (TROs) below
and a total of 20 DBPs including bromate, volatile halogenated organic compounds (VOCs), halogenated acetonitriles (HANs), halogenated acetic acids (HAAs) and chloropicrin. Based on ERA, the 20 DBPs were not considered to have persistency, bioaccumulation and toxicity (PBT) properties. Except monobromoacetic acid, the ratio of predicted environmental concentration (PEC) to predicted no effect concentration (PNEC) of the other 19 DBPs did not exceed 1. Thus, our results of WET testing and ERA indicated that the ballast water effluent treated by electrolysis and subsequently neutralization was considered to have no adverse impacts on marine environment.