• Journal of Advanced Research in Ocean Engineering
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• v.2 no.1
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• pp.28-39
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• 2016

This paper provides theoretical and experimental results to verify the crashworthiness of FH32 high-strength steel for arctic marine structures against ice impact. Assuming that side-shell structures of the Korean arctic research vessel, ARAON, with ice-notation PL10, collide with sheet ice, one-third-scale test specimens with a single transverse frame are manufactured. Impact-bending tests were conducted using a rigid steel striker that mimics sheet ice. Drop height was calculated by considering the speed at which sheet ice is rammed. Prior to impact-bending tests, tensile coupon tests were conducted at various temperatures. The impact-bending tests were carried out using test specimens fully fixed to the inside bottom frame of a cold chamber. The drop-weight velocity and test specimen deformation speed were measured using a high-speed camera and digital image correlation analysis (DICA). Numerical simulations were carried out under the same conditions as the impact-bending tests. The simulation results were in agreement with the test results, and strain rate was a key factor for the accuracy of numerical simulations.

• Proceedings of the KSRS Conference
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• v.2
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• pp.1019-1022
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• 2006

Satellite sea ice data from 1978 to the present reveal that the perennial ice (or ice that survives the summer) has been rapidly declining at almost 10% per decade. Warming due to increases in greenhouse gases in the atmosphere is now also being reflected in winter with drastic reductions in the maximum extent observed in 2005 and 2006. The retreat of the perennial ice also exposes more open water and has revealed an asymmetric distribution of chlorophyll a pigment concentration in the Arctic basin. Phytoplankton blooms are most dominant at high latitudes, partly on account of sea ice, but in the Arctic basin, it appears that pigment concentrations in the Eastern (Laptev Sea) Region are on the average three times higher than those in the Western (Beaufort Sea) Region. Such asymmetry suggests that despite favorable conditions provided by the melt of sea ice, there are other factors that affects the productivity of the region. The asymmetry is likely associated with much wider shelf areas in the East than in the West, with sea ice processes that inhibits the availability of nutrients near the surface in deep water regions, and river run-off that affects nutrient availability. The primary productivity in the pan-Arctic region have been estimated using the pigment concentrations and PAR derived from SeaWiFS data and the results show large seasonal as well as interannual variability during the 1998 to 2005 period. The data points towards increasing productivity for later years but with only 9 years of data it is too early to tell the overall effect of the sea ice retreat.

• ALGAE
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• v.31 no.1
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• pp.61-72
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• 2016

Arctic microalgae thrive and support primary production in extremely cold environment. Three Arctic green microalgal strains collected from freshwater near Dasan Station in Ny-Alesund, Svalbard, Arctic, were analyzed to evaluate the optimal growth conditions and contents of fatty acids. The optimal growth temperature for KNF0022, KNF0024, and KNF0032 was between 4 and 8℃. Among the three microalgal strains, KNF0032 showed the maximal cell number of 1.6 × 107 cells mL^-1 at 4℃. The contents of fatty acids in microalgae biomass of KNF0022, KNF0024, and KNF0032 cultured for 75 days were 37.34, 73.25, and 144.35 mg g^-1 dry cell weight, respectively. The common fatty acid methyl esters (FAMEs) analyzed from Arctic green microalgae consisted of palmitic acid methyl ester (C16:0), 5,8,11-heptadecatrienoic acid methyl ester (C17:3), oleic acid methyl ester (C18:1), linoleic acid methyl ester (C18:2), and α-linolenic acid methyl ester (C18:3). KNF0022 had high levels of heptadecanoic acid methyl ester (26.58%) and heptadecatrienoic acid methyl ester (22.17% of the total FAMEs). In KNF0024 and KNF0032, more than 72.09% of the total FAMEs consisted of mono- and polyunsaturated fatty acids. Oleic acid methyl ester from KNF0032 was detected at a high level of 20.13% of the FAMEs. Arctic freshwater microalgae are able to increase the levels of polyunsaturated fatty acids under a wide range of growth temperatures and can also be used to produce valuable industrial materials.

• Journal of Ocean Engineering and Technology
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• v.32 no.3
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• pp.184-191
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• 2018

Recently, as sea ice in the Arctic has been decreasing due to global warming, it has become easier to develop oil and gas resources buried in the Arctic region. As a result, Russia, the United States, and other Arctic coastal states are increasingly interested in the development of oil and gas resources, and the demand for offshore structures to support Arctic sea resources development is expected to significantly increase. Since offshore structures operating in Arctic regions need to secure safety against various drifting ice conditions, the concept of an ice-strengthened design is introduced here, with a priority on calculation of ice load. Although research on the estimation of ice load has been carried out all over the world, most ice-load studies have been limited to estimating the ice load of the icebreaker in a non-oblique state. Meanwhile, in the case of Arctic offshore structures, although it is also necessary to estimate the ice load according to oblique angles, the overall research on this topic is insufficient. In this paper, we suggest algorithms for calculating the ice load of managed ice (pack ice, 100% concentration) in an oblique state, and discuss validity. The effect of oblique angle according to estimated ice load with various oblique angles was also analyzed, along with the impact of ship speed and ice thickness on ice load.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.1
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• pp.43-48
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• 2017

In recent years, the demand for ships and offshore platforms that can navigate and operate through the Arctic Ocean has been rapidly increasing due to global warming and large reservoirs of oil and natural gas in the area. Winterization design is one of the key issues to consider in the robust structural safety design and building of ships that operate in the Arctic and Sub-Arctic regions. However, international regulations for winterization design in Arctic condition regulated that only those ships and offshore platforms with a Polar Class designation and/or an alternative standard. In order to cope with the rising demand for operating in the Arctic region, existing and new Arctic vessels with a Polar Class designation are lacking to cover for adequate winterization design with HSE philosophy. Existing ships and offshore platform was not designed based on reliable data based on numerical and experiment studies. There are only designed as a performance and functional purposes. It is very important to obtain of reliable data and provide of design guidance of the anti-icing structures by taking the effects of low temperature into consideration. Therefore, the main objective of this paper reconsiders anti-icing design of aluminum helideck using the heating cable. To evaluate of reliable data and recommend of anti-icing design method, various types of analysis and methods can be applied in general. In the present study, finite element method carried out the thermal analysis with cold chamber testing for performance and capacity of heating cables.

• Ocean Systems Engineering
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• v.11 no.4
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• pp.313-330
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• 2021

In this study, the dynamic interaction between an Arctic Spar and drifting level ice is examined in time domain using the newly developed ice-hull-mooring coupled dynamics program. The in-house program, CHARM3D, which is the hull-riser-mooring coupled dynamic simulator is extended by coupling with the open-source discrete element method (DEM) simulator, LIGGGHTS. In the LIGGGHTS module, the parallel-bonding method is implemented to model the level ice using an assembly of multiple bonded spherical particles. As a case study, a spread-moored Artic Spar platform, whose hull surface near waterline is the inverted conical shape, is chosen. To determine the breaking-related DEM parameter (the critical bonding strength), the four-point numerical bending test is used. A series of numerical simulations is systematically performed under the various ice conditions including ice drift velocity, flexural strength, and thickness. Then, the effects of these parameters on the ice force, platform motions, and mooring tensions are discussed. The simulations reveal various features of dynamic interactions between the drifting ice and moored platform for various ice conditions including the novel synchronous resonance at low ice speed. The newly developed simulator is promising and can repeatedly be used for the future design and analysis including ice-floater-mooring coupled dynamics.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.10
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• pp.1044-1048
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• 2015

Recently, the viability of the Northern Sea Route has been receiving a remarkable amount of attention. Owing to global warming, glaciers in the Arctic Ocean have been melting rapidly, which has opened up navigation routes for ships with commercial as well as research purposes. At present, vessels can be economically operated along the Northern Sea Route four months of the year. However, studies have shown that the economical operating time may increase to six months by 2020 and year-round by 2030. Even though the conditions of the Northern Sea Route are extreme, the main reason for its use is that the route is shorter than the existing route using the Suez Canal, which provides an economic benefit. In addition, 25% of the world's oil reserves and 30% of its natural gas are stored in the coastal areas of the East Siberian Arctic region. Many factors are leading to the expectation of commercial navigation using the Northern Sea Route in the near future. To satisfy future demand, the International Maritime Organization established the Polar Code in order to ensure navigation safety in polar waters; this is expected to enter into force on January 1, 2017. According to the code, a ship needs to reduce its speed and analyze the ice for safe operation before entering into it. It is necessary to enter an ice field at a right angle to break the ice safely and efficiently. This study examined the operation along the course for safe navigation of the passage under several conditions. The results will provide guidelines for traffic officers who will operate ships in the Arctic Ocean.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.3
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• pp.376-384
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• 2018

Selection of suitable ice class for ships operation is an important but not simple task. The increased exploitation of the Polar waters, both seasonal periods and geographical areas, as well as the introduction of new international design standards such as Polar Code, reduces the relevancy of using existing experience as basis for the selection, and new methods and knowledge have to be developed. This paper will analyse what can be the limiting ice thickness for ships navigating in the Russian Arctic and designed according to the Finnish-Swedish ice class rules. The permanent deformations of ice-strengthened shell structures for various ice classes is determined using MT Uikku as the typical size of a vessel navigating in ice. The ice load in various conditions is determined using the ARCDEV data from the winter 1998 as the basic database. By comparing the measured load in various ice conditions with the serviceability limit state of the structures, the limiting ice thickness for various ice classes is determined. The database for maximum loads includes 3-weeks ice load measurements during April 1998 on the Kara Sea mainly by icebreaker assistance. Gumbel 1 distribution is fitted on the measured 20 min maximum values and the data is divided into various classes using ship speed, ice thickness and ice concentration as the main parameters. Results encouragingly show that present designs are safer than assumed in the Polar Code suggesting that assisted operation in Arctic conditions is feasible in rougher conditions than indicated in the Polar Code.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.1
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• pp.40-46
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• 2015

Arctic Ocean has rapidly melted due to global warming, by this, commercial ship has been operating through the area. Reason to develop the Northern Sea Route(NSR) even in extreme conditions, the distance than the existing route is shortened, which bring economic benefits. For these reason, the International Maritime Organization(IMO) established safety standards of the Arctic navigation(Polar Code) in order to ensure safe operation in the Northern Sea Route. In this study, it has been described ice types and safety standards of Artic vessel what officer needs to know for safe navigation on the Arctic Ocean. And It was verified by simulation the theoretical knowledge for the safe operation of the Arctic vessel. As a result, it was found that ship needs to reduce speed and analyze ice for safe operation before enter into the ice, it is necessary to enter at right angle to break ice safety and efficiently. Also according to the result of the simulation of navigation entering in ice channel(Lead), it was difficult to change course, it is believed that require emergency training for passing Vessel. In the future, It shall be analyzed precisely under various conditions of scenario.

• Journal of Korea Port Economic Association
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• v.35 no.4
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• pp.1-16
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• 2019

The purpose of this study is to Analyze the problems that container shipping companies exist through the commercialization of container shipping for Non-Arctic countries and the opportunity factors for the transport of the Arctic shipping to improve cooperation cross-border relation Arctic policy and the use of transport. In order to design a hierarchy analysis method study model, four high and 17 low factors were extracted by designing a hierarchy analysis method study model based on results by prior study and in-depth interview. The first of the higher factors is the internal strength of assessing the value of the Arctic, the will and capabilities of the shipping companies in creating new markets with the vision and goals of the shipping companies. Second, the internal constraints associated with the shipping companies advance to the NSR mean the negative factors for the entry into the NSR and the internal weaknesses that cause the shipping companies capacity limitations. Third, the economic benefits from the use of NSR are external factor for shipping companies in cooperation with the future economic value of the Arctic and with respect to Arctic sea and Arctic advance and development from Arctic coastal countries. Finally, external pre-emptive tasks means to respond to use NSR by external restrictions on transport to prepare the possibility of severe weather conditions, the customs policy change of coastal countries.