• 한국산업융합학회 논문집
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• 제23권2_2호
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• pp.181-189
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• 2020

As production, distribution, consumption and processing increase with the development of industrial societies, the importance of resource depletion and environmental problems is increasing day by day. This has led to increased research and interest in remanufacturing that can satisfy both environmental and economic aspects. Currently, the remanufacturing industry is progressed in Korea with automobile parts with as the central figure, and it needs to be expanded into various areas. In this study, the failure type analysis and FMEA were performed on the hydraulic pumps used in construction and industrial sites for the development of the standard remanufacturing process plan, and the actual disassembly and reassembly process was carried out. Remanufacturing products were manufactured through the analysis contents and drawing process, performance tests were conducted in accordance with RS B1501 criteria to evaluate performance, and all of these products passed the test criteria.

• 수산경영론집
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• 제53권3호
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• pp.85-101
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• 2022

This study analyzed the performance of the national fishing port development project, which lacked ex-post impact evaluation despite a lot of investment in terms of fishery income opportunities. Using micro data from the Census of Agriculture, Forestry, and Fisheries, the sales amount of fishery products and the proportion of fishery-related businesses were used as performance indicators. The fishery households in the fishing port area (treatment group) and those not in the area (control group) were classified through data pre-processing, and factors unrelated to the fishing ports were controlled using the propensity score matching difference-in-difference method. The analysis target is six fishing ports with large investment in from 2010 to 2014. As a result of the analysis, it was confirmed that the sales of fishery products increased significantly in four of the six fishing ports, and the proportion of fishery-related businesses increased in two fishing ports. The analysis method of this study can be fully utilized in the evaluation of the Fishing Community New Deal 300 Project, which is in need of performance analysis.

• 한국축산식품학회지
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• 제39권5호
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• pp.844-861
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• 2019

Over the last few years, marine environment was found to be a source of surplus natural products and microorganisms with new bioactive secondary metabolites of interest which can divulge nutritional and biological impact on the host. This study aims to assess the possible, inherent and functional probiotic properties of a novel probiotic strain Enterococcus durans F3 (E. durans F3) isolated from the gut of fresh water fish Catla catla. Parameters for evaluating and describing the probiotics described in FAD/WHO guidelines were followed. E. durans F3 demonstrated affirmative results including simulated bile, acid and gastric juice tolerance with exhibited significant bactericidal effect against pathogens Staphylococcus aureus, Salmonella Typhi, Escherichia coli and Pseudomonas aeruginosa. This can be due to the enterocin produced by E. durans F3 strain, which was resolute by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) gel with amplification of the anticipated fragment of a structural gene; enterocin A, followed by antibiotic susceptibility assessment. Effective antioxidant potentiality against ${\alpha}$-diphenyl-${\alpha}$-picrylhydrazyl free radicals including lipase, bile salt hydrolase activity with auto-aggregation and cell surface hydrophobicity was similarly observed. Results are proving the potentiality of E. durans F3, which can also be used as probiotic starter culture in dairy industries for manufacturing new products that imparts health benefits to the host. Finding the potent and novel probiotic strains will also satisfy the current developing market demand for probiotics.

• Corrosion Science and Technology
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• 제14권2호
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• pp.54-58
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• 2015

A heavy oil of low quality has been mainly used in the diesel engine of the merchant ship as the oil price has been significantly jumped for several years. Thus, a combustion chamber of the engine has been often exposed to severely corrosive environment more and more because temperature of the exhaust gas of the combustion chamber has been getting higher and higher with increasing of using the heavy oil of low quality. As a result, wear and corrosion of the engine parts such as exhaust valve, piston crown and cylinder head surrounded with combustion chamber are more serious compared to the other parts of the engine. Therefore, an optimum repair welding for these engine parts is very important to prolong their lifetime in a economical point of view. In this study, 1.25Cr-0.5Mo filler metal was welded with SMAW method in the forged steel which would be generally used with piston crown material. And the corrosion properties of weld metal, heat affected and base metal zones were investigated using electrochemical methods such as measurement of corrosion potential, anodic polarization curves, cyclic voltammogram and impedance etc. in 35% $H_2SO_4$ solution. The weld metal and base metal zones exhibited the highest and lowest values of hardness respectively. And, the corrosion resistance of the heat affected and weld metal zones was also increased than that of the base metal zone. Furthermore, it appeared that the corrosive products with red color and local corrosion like as a pitting corrosion were more frequently observed on the surface of the base metal zone compared to the heat affected and weld metal zones. Consequently, it is suggested that the mechanical and corrosion characteristics of the piston crown can be predominantly improved by repair welding method using the 1.25Cr-0.5Mo electrode.

• 한국수산과학회지
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• 제48권4호
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• pp.454-458
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• 2015

This study compared the effects of dietary supplementation of citrus by-product (CBP) and CBP fermented with Bacillus subtilis (F-CBP) on growth performance, feed utilization, intestinal histology and innate immunity of red seabream Pagrus major with three commercial immune-boosting products. The six experimental diets were supplemented with L-ascorbyl-2-polyphosphate (LAPP; the control diet), CBP or F-CBP at a concentration of 100 mg vitamin C equivalent/kg diet or one of three commercial immune boosters. The Experimental diets were fed to triplicate groups of 17 fish (initial body weight, 116 g) for 8 weeks. The water temperature during the feeding trial was maintained at $13-15^{\circ}C$. Growth and feed utilization did not differ significantly among the six dietary treatments, nor did the phagocytic activity, superoxide dismutase or total immunoglobulin concentrations. However, myeloperoxidase activity was significantly higher in the CBP groups. For the intestinal histology, the intestine diameter, villi and enterocyte heights and number of goblet cells did not differ significantly among groups. Therefore, CBP or F-CBP can be used as a valuable eco-friendly byproduct in diets for fishes including red seabream to maintain their normal growth and health.

• Corrosion Science and Technology
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• 제19권2호
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• pp.100-107
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• 2020

The demand for powder-coated steel used in the marine industry is increasing owing to their superior corrosion resistance. However, the powder coatings used in commercial products can deteriorate easily by the penetration of brine. In an attempt to suppress brine penetration into the powder coating and significantly increase the corrosion resistance, three types of oxide particles were added to the coating. Electrochemical impedance spectroscopy tests in 3.5% NaCl solution were performed to evaluate the corrosion behaviors of the powder coating with oxide particles. The results showed that the addition of SiO₂ particles to a powder coating severely decreased the corrosion resistance due to the easy detachment of agglomerated SiO₂ particles with a coarse size from the coating layer. In contrast, the TiO₂ and SnO₂-added coatings showed better corrosion resistance, and the TiO₂-added coating performed best in the test conducted at room temperature. However, conflicting results were obtained from tests conducted at a higher temperature, which may be attributed to the effective suppression of brine penetration by the fine SnO₂ particles uniformly distributed in the coating.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 춘계학술대회
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• pp.673-676
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• 2017

국내 해양 시추용 시스템(드릴십, 시추 리그)의 건조시 머드 시스템은 전면 수입에 의존하며, 소수 외국 대기업의 독과점 현상이 심화되고 있다. 또한, 현재까지 국내 기술개발은 대부분 단품 위주의 제품개발을 시도하였으나, 패키지 단위의 제품 개발방법으로 접근하여 개별 장비를 패키지 단위의 사업화를 위해서는 모니터링제어시스템에 대한 개발이 필요하다. 따라서, 본 연구과제를 통해 기 개발된 국산화 머드 시스템의 단일 장비들을 통합 운영할 수 있는 제어모니터링 시스템을 개발 한다.

• 한국표면공학회지
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• 제51권4호
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• pp.224-230
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• 2018

In this study, Mg films were prepared on hot dip aluminized steel (HDA) by using a sputtering method as a high corrosion resistance coating. The corrosion resistance of the Mg films was improved by controlling the morphology and the crystal structure of films by adjusting the Ar gas pressure during the coating process. Anodic polarization measurement results confirm that the corrosion resistance of the Mg films was affected by surface morphology and crystal structure. The corrosion resistance of the Mg coated HDA specimen increased with decreasing crystal size of the Mg coating and it was also improved by forming a film with denser morphology. The crystal structure oriented at Mg(101) plane showed the best corrosion resistance among crystal planes of the Mg metals, which is attributed to its relatively low surface energy. Neutral salt spray test confirmed that corrosion resistance of HDA can be greatly improved by Mg coating, which is superior to that of HDG (hot dip galvanized steel). The reason for the improvement of the corrosion resistance of Mg films on hot dip aluminized steel was due to the barrier effect by the Mg corrosion products formed by the corrosion of the Mg coating layer.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제7권6호
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• pp.221-228
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• 2018

최근 ICT 기반 고부가가치 조선해양 산업 요구의 증가로 조선해양 분야의 소프트웨어 비중과 중요성에 대한 기대가 높아지고 있다. 본 논문에서는 재사용 소프트웨어 컴포넌트 개발을 통해 조선해양 분야 소프트웨어 경쟁력을 향상시키는 것을 목적으로 수행한, 설문조사 기반의 조선해양 소프트웨어 개발 환경 분석 결과를 제시한다. 설문조사는 서로 다른 업체에 종사하는 34명의 조선해양 소프트웨어 개발자들을 대상으로 수행 하였으며, 설문 항목은 소프트웨어 개발 업체의 규모나 개발 제품의 기술 분류와 같이 조사 대상 SW 개발 업체 정보를 파악하기 위한 항목과 소프트웨어 개발이 수행되는 플랫폼, 언어, 배포 형태, 컴포넌트 개발 방해 요인, 개발 프로세스 및 품질관리 도구 사용 여부 등의 소프트웨어 개발과 직접적인 관련이 있는 항목들로 구성하였다. 설문조사 분석 결과에 따르면 개발자들이 개발환경을 선택할 때 가장 큰 영향을 미치는 요소는 이용 가능한 도구의 다양성과 기술지원 여부였으며, 성능, 제품의 가격, 보안이 그 다음 고려사항이었다. 또한 소프트웨어 경쟁력 향상을 위한 한 가지 방법인 재사용 컴포넌트의 개발을 가로막고 있는 주요한 원인은 다양한 플랫폼 지원과 신뢰성 보장의 어려움, 개발 비용과 인력 부족으로 조사되었다. 마지막으로, 개발 프로세스와 품질관리 도구를 전면적으로 사용하여 체계적으로 소프트웨어를 개발하고 있는 개발자의 비율은 전체 조사대상 개발자의 15% 정도에 불과한 것으로 조사되었다. 이러한 사실로부터 현재 조선해양 업체들의 고품질 소프트웨어 개발 능력을 향상시키기 위해서는 해당 업체들에 대한 기술적 제도적 지원이 필요한 상황임을 알 수 있었다.

• 해양환경안전학회지
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• 제25권2호
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• pp.237-243
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• 2019

PE(PolyEthylene) 재료를 활용한 해상부유 구조물은 바다, 강 또는 호수의 인근이나 수역 내에 일정한 공간 부를 형성하는 부유식 구조물로, 현재는 그 용도가 소형선박 계류장뿐만 아니라 양식장, 수상 펜션, 해상부교 등에 다양하게 활용되고 있다. 이 제품군의 특징은 유연성이 뛰어나고 재활용할 수 있으며, 내약품성, 내후/내식성이 우수하다. 기존의 PE 제품군을 활용한 부유식 플랫폼은 한 개의 브래킷에 한 개의 부력관을 체결하는 단순한 구조를 구성하였고, 이로 인하여 사용자가 용도 변경 및 사용환경이 변경될 때는 적용하는데 제한이 있었다. 이에 본 연구에서는 한 개의 브래킷에 다양한 크기를 갖는 부력 관을 체결할 수 있는 구조를 개발하고, 제품의 구조 안전성을 유한요소법을 활용하여 검증하였다. 구조해석 결과, 브래킷 하단에 지름 500 mm 부력관 모델에서 충돌 하중에 대해 최대값을 나타내었으나, 허용기준을 만족하였다. 본 연구 결과를 기반으로 하여, 향후 다양한 형태의 부유체 플랫폼에 대한 구조 안전성 평가에 관한 연구가 가능하며, 관련 평가 기준에 대한 정립이 필요하다.