• Title/Summary/Keyword: sea state

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Energy Efficiency Evaluation of IT based Ship Energy Saving System-(1) : Ship Handling Simulator Test Results (IT 기반의 선박에너지절감시스템 성능평가 방법-(1) : 육상시험 수행 결과)

  • Yoo, Yun-Ja
    • Journal of Navigation and Port Research
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    • v.39 no.6
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    • pp.465-472
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    • 2015
  • SEEMP (Ship Energy Efficiency Management Plan) guidelines for a ship's GHG reduction include a machinery modification of hull, an installation of energy efficiency enhanced attachment in hardware methods. It is also possible to bring a ship energy efficiency improvement by fuel-efficient operations or in other software methods. Hardware modification or installation on ship can bring financial burdens to a ship company compared to its improvement expectation. On the other hand, Software based energy-saving technology can be applicable on various ship types, and it is also expected high efficiency of ship energy use compared to hardware based technology in perspective of the investment costs and efficiency. In this paper, it is described that the ship handling simulator based evaluation was carried out using representative ship model of bulk, container and VLCC. Simulation environments were separated into 6 conditions according to the sea-state and weather condition, and the operation results were compared with those before and after energy saving system applied The container ship showed the largest FOC save rate after energy saving system applied although the others also showed energy save rate after using the system.

The Effect of Stress on SCC of Heat Exchanger Tube for LNG Vessel (LNG선박용 열교환기 세관의 SCC에 미치는 응력의 영향)

  • Jeong Hae Kyoo;Lim Uh Joh
    • Journal of the Korean Institute of Gas
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    • v.7 no.2 s.19
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    • pp.22-32
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    • 2003
  • Al-brass material is generally used at the state of plastic deformation, for example; bending, extension of bell mouth at shell and tube type heat exchanger. And SCC(stress corrosion cracking) of Al-brass material will be affected by residual stress as plastic deformation. SCC results from synergism between mechanical factor and corrosion environment. Mechanical factor is stress that directly relates with stress intensity factor at the crack tip. This paper was studied on the effect of stress on SCC of Al-brass tube under in $3.5\%$ NaCl. + $0.1\%\;NH_4OH$ solution by constant displacement tester. Increasing of acidified water flow into sea and speeds up corrosion rate of Al-brass which is used as a tube material of vessel heat exchanger by polluted coast seawater. The experimental results are as follow The latent time of SCC occurrence gets longer as the initial stress intensity factor($K_{Ii}$) gets lower The main crack was propagated as the initial stress intensity factor($K_{Ii}$) gets higher, and secondary cracks occurred by electro-chemical factor a(ter stage of released stress. Dezincification phase showed around the crack, and the range of dezincification gets wider as the initial stress intensity factor($K_{Ii}$) gets higher.

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Isolation and Characterization of a Marine Bacterium Producing Thermotolerant Agarase (내열성 한천분해효소를 생산하는 해양세균의 분리 및 특성)

  • Park Ceun-Tae;Lee Dong-Ceun;Kim Nam Young;Lee Eo-Jin;Jung Jong-Ceun;Lee Jae-Hwa;Heo Moon-Soo;Lee Jung-Hyun;Kim Sang-Jin;Lee Sang-Hyeon
    • Journal of Life Science
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    • v.15 no.6 s.73
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    • pp.884-888
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    • 2005
  • An agar-degrading bacterium was isolated from north-eastern sea of Jeju island and cultured in marine agar 2216 media. Biochemical and morphologicl characteristics and 165 rRNA gene revealed that isolated strain was member of Agarivorans genus, and named Agarivorans sp. JA-1. Agarase was produced as growth-related and expressed regardless of agar presence. Optimal pH was 8 at 50 mM Clycine-NaOH buffer, and activity was maximum at $40^{\circ}C$E Enzymatic activity was maintained over $80\%$ at $60^{\circ}C$t and $70\%$ at $80^{\circ}C$ which is thermotolerant. Hence isolated novel Agarivorans sp. JA-1 strain and its beta-agarase could be used for the production of functional oligosaccharide from agar in solution state.

A Study on the Cultural Landscape Characteristics of Village Forest Sites in the Southern Coast - A Case Study of Namhae-Goon and Tongyoung City - (경상남도 남해안 마을숲의 문화경관 특성 연구- 남해군과 통영시를 중심으로 -)

  • Lim, Eui-Je;So, Hyun-Su;Lee, Soo-Dong
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.30 no.3
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    • pp.29-41
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    • 2012
  • This study's objective is to inform people of the value and identity and to understand the cultural landscape characteristics of coastal village forest, which have not been studied in-depth in previous studies. This study was conducted by selecting 10 village forest sites in the southern coast of Gyeongsangnam-do, Korea and the present state of forests were investigated through bibliographical and on-the-spot survey, as well as interviews with local villagers. The following points(characteristics of traditional culture, practical characteristics, scenic characteristics) are the important factors for analyzing cultural landscape characteristics of coastal village forest verified through the study. First, The coastal village forest in the village commons is mental space for the local community affected by folk belief rather than confucian backgrounds. Second, The coastal village forest is a reasonable space contriving economic efficiency and solving the real problems facing the coastal village. Third, The coastal village forest identities should be understood the land use around village and behind mountain from the sea of wide range rather than confined to just a forest consisting of trees. This study's significance is to make the basic data and to enhance the value of the coastal village forest unnoticed. In addition, the subjects of the study should be extended to the east and west coastal village forests and subsequent research should be conducted to notification the characteristics and differences of each coastal village forest.

Possibility of Fishery in Offshore Wind Farms (해상풍력발전단지 내 어업 가능성에 관한 고찰)

  • Jung, Cho-Young;Hwang, Bo-Kyu;Kim, Sung-Cheol
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.25 no.5
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    • pp.535-541
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    • 2019
  • The purpose of this study was to investigate the possibility of fishery in offshore wind farms and evaluate the risk linked to the presence of turbines and submarine cables in these areas. With this objective, we studied an offshore wind farm in the Southwest Sea and the current state of vessels in the surrounding National Fishing Port. The risk assessment criteria for 22 fishing gears and methods were set by referring to the fishing boats; thereafter, the risk was assessed by experts. The fishing gears and methods that could be safely operated (i.e., associated with low risk) in the offshore wind farm were: single-line fishing, jigging, and the anchovy lift net. The risk was normal so that it is possible to operate, but the fishing gears and methods that need attention are: the set long line, drifting long line, troll line, squid rip hook, octopus pot, webfoot octopus pot, coastal fish pot, stow net on stake, winged stow net, stationary gill net, and drift gill net. Moreover, the fishing gears and methods difficult to operate in the of shore wind farm (i.e., associated with high risk) were: the dredge, beam trawl, and purse seine. Finally, those associated with very high risk and that should not be allowed in offshore wind farms were: the stow net, anchovy drag net, otter trawl, Danish seine, and bottom pair trawl.

The social role of record information management for Sewol ferry disaster (세월호 참사에 관한 기록정보관리 분야의 사회적 역할)

  • Kim, Jin Sung
    • The Korean Journal of Archival Studies
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    • no.44
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    • pp.199-215
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    • 2015
  • This study suggest the social role of record information management for Sewol ferry disaster on sea near Jindo-gun at April 16, 2014. Social each part and the discrete member be going to carry out the social role for the disaster so that record information management part may be gather, operate, provide related record informations. Record informations is ways to reflect, to supplement about something and means to effect it. They naturally generated though automatic managed, it need to purposeful activity. From finding to lack, to remedy a problem, Korean society and record information management part shall be reinforcing directions and competency of the solution with various angles. Practical union and assistance of record information management part for Sewol ferry disaster, at first it be a help to recognize officially evidence for the accident. Secondary it producing and using better than current state of the area's record information part. Finally it may be actively comprise and implement our competency and emotion.

A Scheme for listing on FAO GIAHS and Preservation of Juk-Bang-Ryeum in the Southern Coast of Korea (남해안 죽방렴의 세계중요농어업유산 등재 및 보존 방안)

  • Lee, Kyung-Joo;Kwon, Hojong;Jeong, Dae-Yul
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.9 no.4
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    • pp.325-336
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    • 2019
  • There are many bamboo weir (Juk-Bang-Ryeum) with the highest preservation value as a fisheries heritage from Sacheon to Namhae area in the Korea Hanrye National Marine Park. It was designated as a Korea National Cultural Property Sightseeing No. 71, and also as an important fishery asset listed in the Korea National Important Fisheries Heritage No. 3. It is an important cultural heritage that should be preserved for the future as a community asset to the local residents, and should be preserved as it's original form because of unique traditional fishery style in the world as well as natural environment oriented fishing system. The purpose of this study is to review the value of Juk-Bang-Ryeum in the South Sea as well as to preserve the tradition of it. This paper will make a contribution to the registration of it on the list of World Important Agricultural and Fishery Heritage (GIAHS), which is recognized by the United Nations Food and Agriculture Organization (FAO). To make basic data for listing on it, we will analyze the characteristics and structure of Juk-Bang-Ryeum, and also research the value of it from the historical literature review as well state of arts. We also develop a scheme for listing on FAO GIAHS through checking necessary items step by step. Finally, we suggest some idea to preserve it more effectively.

A Study on Paradigm Shift of Ship Inspection System (선박검사제도 패러다임 전환에 관한 고찰)

  • Song, Byung-Hwa;Lee, Chang-Hyun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.28 no.1
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    • pp.30-38
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    • 2022
  • According to the United Nations Convention on the Law of the Sea (Article 94), the flag state must fulfill its overall role to ensure maritime safety and operate the ship inspection system as a related measure. The Korean government (Ministry of Ocean and Fisheries) has implemented policies for reducing marine accidents to promote maritime safety; however, the target goal has not been achieved. The ship inspection system is a measure to prevent marine accidents, and for the effective operation of the system, a sufficient understanding of the origin of the ship inspection system is required. In this study, the trend of the international ship inspection system was identified by analyzing ship inspection system origins and the history of the system's paradigm shift. The recent international ship inspection system paradigm confirms international standardization and the active safety management of ship companies are becoming increasingly prominent. Based on this, the introduction of the 'PDCA cycle-based self-inspection system' is presented to the current domestic ship inspection system. This is a new type of inspection system that establishes the roles of interested parties based on the basic philosophy of the ISO 9000 series to improve the ef ectiveness of maritime safety. Additionally, the necessity for a non-face-to-face ship inspection system has emerged because of the COVID-19 pandemic. Hence, the transition to a 'mobile application-based ship inspection system' is proposed to accommodate the rapid development of information communications technology.

Analysis on the Rigid Connections of the Drilled Shaft with the Cap for Multiple Pile Foundations (현장타설말뚝을 적용한 다주식 기초에서 말뚝과 캡의 강결합에 대한 분석)

  • Cho, Sung-Min
    • Journal of the Korean Geotechnical Society
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    • v.24 no.7
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    • pp.61-73
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    • 2008
  • Piles of a bridge pier are connected with the column through the pile cap (footing). Behavior of the pile foundation can be different according to the connection method between piles and the pile cap. Connection methods between pile heads and the pile cap are divided into two groups : rigid connections and hinge connections. Domestic design code has been specified to use rigid connection method for the highway bridge. In the rigid connection method, maximum bending moment of a pile occurs at the pile head and this helps the pile to prevent the excessive displacement. Rigid methods are also good to improve the seismic performance. However, some specifications prescribe that conservative results through investigations of both the fixed-head condition and the free-head condition should be reflected in the design. This statement may induce an over-estimated design for the bridge which has high-quality structures with casing covered drilled shafts and the PC-house contained pile cap. Because the assumption of free-head conditions (hinge connections) is unreal for the elevated pile cap system with multiple piles of the long span sea-crossing bridges. On the other hand, elastic displacement method to evaluate the pile reactions under the pile cap is not suitable for this type of bridges due to impractical assumptions. So, full modeling techniques which analyze the superstructure and the substructure simultaneously should be performed. Loads and stress state of the large diameter drilled shaft and the pile cap for Incheon Bridge which will be the longest bridge of Korea were investigated through the full modeling for rigid connection conditions.

The Effect of Phases of Starting Materials on the Grain Size at High Pressure: the Comparison of Grain Size in the Samples Using Glass and Nano Powder as Starting Materials (고압환경에서의 결정 크기에 원시료의 상이 미치는 영향: 비정질 시료와 나노파우더를 이용한 시료의 결정 크기 비교)

  • Eun Jeong Kim;Alessio Zandona;Takehiko Hiraga;Sanae Koizumi;Nobuyoshi Miyajima;Tomoo Katsura;Byung-Dal So
    • Korean Journal of Mineralogy and Petrology
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    • v.36 no.3
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    • pp.213-220
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    • 2023
  • In this study, we report the effect of starting materials on the grain size in a multi-component system at high pressure experiments. We used two different starting materials, glass and nano powders, to synthesize bridgmanite in the reduced conditions in the presence of calcium-ferrite-phase MgAl2O4 to compared the grain size of synthesized samples. After synthesizing the sample at 40 GPa, 2000 K for 20 hrs, the sample from glass showed the grain size of 50-200 nm whereas the one from nano powders has ~500 nm of grains. This difference may come from 1) the temperature of 2000 K which is low enough for glass starting materials to make more crystal nucleis than to grow crystal size or 2) the possible difference in the redox state of starting materials. It is suggested that the using of nano powders is better to synthesize bigger grains in high pressure experiments with multi-component systems rather than using glass starting materials.