• Journal of the Society of Naval Architects of Korea
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• v.57 no.3
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• pp.124-132
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• 2020

The purpose of this paper is to establish the basic procedure and method for selection of preferred anti-fouling paint considering economic analysis according to ship's speed loss based on ISO 19030 that has been published in 2016 to prescribe practical methods for measuring changes in ship specific hull and propeller performance. In this study, six (6) anti-fouling paint products have been assumed for alternatives with each target maximum average speed loss and carried out comparison of the alternatives and sensitivity analysis in assumed conditions for selection of the preferred alternative.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.199-209
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• 2018

Polyethersulfone (PES)/sulfonated $TiO_2$ ($STiO_2$) nanoparticles (NPs) UF blended membranes were fabricated with different loadings of $STiO_2$. The modified membranes exhibited significant improvement in surface roughness, porosity, and pore size when compared to the PES membrane. The $P-STiO_2$ 1 and $P-TiO_2$ 1 blended membranes exhibited higher water flux, approximately 102.4% and 62.6%, respectively, compared to PES. SPP-$STiO_2$ and $P-STiO_2$ showed lower Rir fouling resistance than the $P-TiO_2$ blended membrane. Overall, the $STiO_2$-blended membranes provide high hydrophilicity permeability, anti-fouling performance, and improved BSA rejection attributed to the hydrogen bonding force and more electrostatic repulsion properties of $STiO_2$.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.1921-1927
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• 2014

A new method for optimizing the magnetic field gradient in the exciting coil of electronic anti-fouling (EAF) system is presented based on changing exciting coil size. In the proposed method, two optimization expressions are deduced based on biot-savart law. The optimization expressions, which can describe the distribution of the magnetic field gradient in the coil, are the function of coil radius and coil length. These optimization expressions can be used to obtain an accurate coil size if the magnetic field gradient on a certain point on the coil's axis of symmetry is needed to be the maximum value. Comparing with the experimental results and the computation results using Finite Element Method simulation to the magnetic field gradient on the coil's axis of symmetry, the computation results obtained by the optimization expression in this article can fit the experimental results and the Finite Element Method results very well. This new method can optimize the EAF system's anti-fouling performance based on improving the magnetic field gradient distribution in the exciting coil.

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.168-168
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• 2017

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.609-616
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• 2019

When the fouling of a vessel occurs, its resistance at sea increases and there is a corresponding increase in fuel consumption. The maintenance cost of the vessel also increases because it is time-consuming to remove the fouling. To solve this problem and minimize environmental contamination of sea-water, there have been recent developments in anti-fouling paints as self-polishing copolymers that not include toxic elements such as tin. When these conventional techniques are applied to vessels, polishing is promoted during the operation whereby friction or vibration with seawater occurs. This leads to enhanced anti-fouling performance. However, when fouling is intensified such as during an anchorage, there is no flow of seawater and polishing is suppressed. This leads to a deterioration of the performance of anti-fouling. To solve these problems, we developed a system that induces vibration in a vessel during anchorage. As such, the deterioration of polishing due to insuf icient flow of seawater is inhibited. The reliability of the ultrasonic antifouling system was evaluated by calculating its repeatability. The removal efficiency of fouling of the proposed system was qualitatively evaluated using test specimens. The test revealed that the value of the coefficient of variation for the reproducibility of the frequency and amplitude was 0.2 % and 4.0 % on average. The degree of fouling of the specimens was the highest at 73.3 g in the No.5 sepcimen. Moreover, efficiency of fouling removal was 93.2 % on average compared to the specimens without the proposed system.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.469-477
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• 2021

In this study, the mechanical property of anti-fouling coating using CNF was evaluated to prevent the durability and stability of structure exposed the marine environment. Anti-fouling coating using CNF was prepared by CNF, AKD and waste glass powder, and contact angle test, drying time, viscosity analysis and microstructure were performed. When coating on one number of times, It was showed to relatively high hydrophobic performance in steel. And It was confirmed that the contact angle increased as the content of AKD increased in cement mortar. When coating on three number of times, the surface was confirmed super-hydrophobic at maximum of 151.6°. When mixing waste glass powder, the surface was showed to relatively high hydrophobic. It is pseudo plastic fluid when CNF and distilled water were prepared in a ratio of 1:1, And Anti fouling coating is judged to be suitable for use as coating on marine structure.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.5
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• pp.400-409
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• 2016

In recent, shipping companies have made an enormous effort to improve the operation of vessel in various approaches, due to recession of shipping market and increasing competition among shipping companies. One of important parameters for improving the efficiency of vessel is the resistance performance that consist of friction and residual resistance. Especially, it is recognized that the friction resistance tends to be affected by conditions of vessel’s surface and occupies approximately 70~90% of the total resistance for slow speed ships. In general, the surface of vessel is covered with various type of paint to reduce fouling and corrosion. As time goes by, however, it is so hull roughness would be increased by fouling over the wetted surface that anti-fouling paints, such as CDP(Controlled Depletion Paint), Tin-Free SPC(Self Polishing Co-polymer) or Foul Release, are applied evenly on the hull surface. Nevertheless, these anti-fouling paints could not prevent fouling absolutely. A fundamental study on evaluating ship resistance performance variation due to hull roughness has been performed using a commercial software, Star-CCM+, which solves the continuity and Navier-Stokes equations for incompressible and viscous flow. The results of present simulation for plate are compared with some experimental data available and the effect of surface roughness to ship resistance performance is discussed.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.1
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• pp.71-81
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• 2017

In this study, a series of full-scale extrapolation procedures based on the Granville's similarity scaling method, which was employed by Schultz (2007), is modified and then applied to compare the resistance performance between two different anti-fouling coatings. As an analysis example, the low frictional AF coating based on a novel skin-friction reducing polymer named FDR-SPC (Frictional Drag Reduction Self-Polishing Copolymer), which had been invented by the present author, is employed. The low frictional coating, which gives 25.4% skin frictional reduction in lab test, is estimated to give 18.2% total resistance reduction for a 176k DWT bulk carrier.

• Membrane and Water Treatment
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• v.6 no.3
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• pp.205-224
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• 2015

A novel hydrophilic poly (vinylidene fluoride)/poly (p-phenylene terephthalamide) (PVDF/PPTA) blend membrane was prepared by in situ polycondensation of p-phenylene diamine (PPD) and terephthaloyl chloride (TPC) in PVDF solution with subsequent nonsolvent induced phase separation (NIPS) process. For comparison, conventional solution blend membrane was prepared directly by adding PVDF powder into PPTA polycondensation solution. Blend membranes were characterized by means of viscometry, X-ray photoelectron spectroscopy (XPS), Field Emission Scanning Electron Microscopy (FESEM). The effects of different blending methods on membrane performance including water contact angle (WCA), mechanical strength, anti-fouling and anti-compression properties were investigated and compared. Stronger interactions between PVDF and PPTA in in situ blend membranes were verified by viscosity and XPS analysis. The incorporation of PPTA accelerated the demixing rate and caused the formation of a more porous structure in blend membranes. In situ blend membranes exhibited better hydrophilicity and higher tensile strength. The optimal values of WCA and tensile strength were $65^{\circ}$ and 34.1 MPa, which were reduced by 26.1% and increased by 26.3% compared with pure PVDF membrane. Additionally, antifouling properties of in situ blend membranes were greatly improved than pure PVDF membrane with an increasing of flux recovery ratio by 25%. Excellent anti-compression properties were obtained in in situ blend membranes with a stable pore morphology. The correlations among membrane formation mechanism, structure and performance were also discussed.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.83-83
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• 2014

선박건조에 사용되는 도료 중 SPC(self-polishing copolymer) A/F(anti-fouling) 도료의 주된 기능은 해양생물의 부착 등 해양생물에 의한 오염을 방지하는 방오성능으로 인식되어 왔으나, 최근 방오성능 뿐 아니라 선박의 운항 시 선체저항을 줄임으로써 발생되는 연료절감효과와 선박의 미관을 위한 변색지연 등 SPC A/F 도료의 다른 기능에 많은 관심을 가지게 되었다. 이러한 관심과 사용자의 요구에 따라 도료사에서는 항력의 감소를 가져 올 수 있는 Silyl acrylate copolymer로 디자인 된 Silyl acrylate SPC A/F 도료를 개발하였으나 SPC A/F 도료의 방오제(biocides) 종류에 따른 방오성능 차이를 비교 평가 할 수 있는 객관적 자료가 부족하여, 본 연구를 통해 SPC A/F 도료의 종류 별 방오성능을 평가하고자 한다.