• 한국항행학회논문지
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• 제12권4호
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• pp.304-310
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• 2008

삼면이 바다인 우리 해양은 각종 폐기물로 인하여 환경오염 피해가 심각한 상태이다. 따라서 폐기물 중 상당부분을 차지하고 있는 그물을 적극적인 태도로 관리한다면 환경오염은 상당히 줄어들 것이며, 이로 인하여 해양 생태계에도 큰 도움이 될 것으로 본다. 본 연구는 선박에서 투망하는 그물 및 회수된 그물을 파악하기 위한 그물관리 시스템을 개발하고자 한다. 그물관리 관리 시스템은 해양에 투기되는 그물을 관리하기 위하여 선박 입항과 출항 내역을 관리하고, 해양에 무단으로 투기된 폐그물의 발생을 억제 시켜서 폐그물로 인한 환경오염 및 해양 선박 침몰사고를 방지하는데 그 목적을 둔다.

• 한국안전학회지
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• 제11권4호
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• pp.90-96
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• 1996

This paper examines the De-inking characteristics of mechanical methods using the newly developed De-inking machine along with experiments to enhance the manufacture of recycled kraft pulp with the addition of newspaper. This study concluded that : First, the De-Inking ratio was affected by shear stress and friction resistance operating In the stainless steel net. Second, the brightness improvement ratio was raised by 6.2% under the following conditions : 120rpm rotor speed, 2.18% concentration, using two treatment cycles. Third, it was shown that the tearing strength was improved by about 10 to 20% , and the tensile strength remained the same when recycled kraft pulp was added with 20% wasted paper. In sum, by these experiments we have proven that the performance of the newly developed De-inking machine can be improved.

• 수산해양교육연구
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• 제11권1호
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• pp.24-42
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• 1999

I have studied historical transition process of fisheries industries, fisheries Institute in abreast of developing fisheries industries of west coast of Korea since 1910 year with regard to the Gogunsan Is. The results were summarized as follows. In 1910 year, fishery industry has been carried out shifting fishing gear e.g set-net in shallow waters, small stow net, small seine net adapting to the tophorgrapical feature, shape of coast, oceanic condition, however, the fishing gear and fishing method were undeveloped, so that, Japanese fishermen had been exploited fisheries resources penetrating the fishing ground. Most important species were lot of captured croaker, cod, spanish mackeral, sea abream, herring in coastal sea. nowaday, squid, anchovy, shrimp, crab, pompret were much captured. The species were captured in 18 century were not captured. It is rarely than that period. Fishereis aquatic culture had been not farmed till 1960 year, but sea laver, shrimp, crab, had been breeded 1970 year also, the fresh water fish e.g. eel, cat-fish had been breeded activately. The fisheries processing industry were composed of salt. icing, dry, method. the salted fish industry had been prevailed at Gangyng, Kwangchon, Kunsan, Julpo comparatively. The fisheries institute had been established at Kunsan at first, but institute established in other region had been abolished in a short time. This phenomenon was related with development of fisheries resources. The western coast fisheries industries had been wasted of decreasing of fisheries resources, variation of environment. Accordingly, the study of preserving the marine resources. educated man power who engaged in fisheries field have to accomplish. Sea was dying with reason of loss of mud in west coast factory waste, waste of life the increase of accident of sea polluted, each illegal fishing industry physical and chemical reason etc. in this respect, Kusan maritime college, fisheries developing agency, institute have to take important role for developing fishing industry.

• Nuclear Engineering and Technology
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• 제40권1호
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• pp.49-68
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• 2008

The purpose of this paper is to extensively review the condition monitoring (CM) techniques using empirical models in an effort to reduce or eliminate unexpected downtimes in general industry, and to illustrate the feasibility of applying them to the nuclear industry. CM provides on-time warnings of system states to enable the optimal scheduling of maintenance and, ultimately, plant uptime is maximized. Currently, most maintenance processes tend to be either reactive, or part of scheduled, or preventive maintenance. Such maintenance is being increasingly reported as a poor practice for two reasons: first, the component does not necessarily require maintenance, thus the maintenance cost is wasted, and secondly, failure catalysts are introduced into properly working components, which is worse. This paper first summarizes the technical aspects of CM including state estimation and state monitoring. The mathematical background of CM is mature enough even for commercial use in the nuclear industry. Considering the current computational capabilities of CM, its application is not limited by technical difficulties, but by a lack of desire on the part of industry to implement it. For practical applications in the nuclear industry, it may be more important to clarify and quantify the negative impact of unexpected outcomes or failures in CM than it is to investigate its advantages. In other words, while issues regarding accuracy have been targeted to date, the concerns regarding robustness should now be concentrated on. Standardizing the anticipated failures and the possibly harsh operating conditions, and then evaluating the impact of the proposed CM under those conditions may be necessary. In order to make the CM techniques practical for the nuclear industry in the future, it is recommended that a prototype CM system be applied to a secondary system in which most of the components are non-safety grade. Recently, many activities to enhance the safety and efficiency of the secondary system have been encouraged. With the application of CM to nuclear power plants, it is expected to increase profit while addressing safety and economic issues.

• Nuclear Engineering and Technology
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• 제51권1호
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• pp.176-189
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• 2019

This paper presents a feasibility study for producing the medical isotope $^{99m}Tc$ using the hazardous and currently wasted radioisotope $^{99}Tc$. This can be achieved with the nuclear resonance fluorescence (NRF) phenomenon, which has recently been made applicable due to high-intensity laser Compton scattering (LCS) photons. In this work, 21 NRF energy states of $^{99}Tc$ have been identified as potential contributors to the photo-production of $^{99m}Tc$ and their NRF cross-sections are evaluated by using the single particle estimate model and the ENSDF data library. The evaluated cross sections are scaled using known measurement data for improved accuracy. The maximum LCS photon energy is adjusted in a way to cover all the significant excited states that may contribute to $^{99m}Tc$ generation. An energy recovery LINAC system is considered as the LCS photon source and the LCS gamma spectrum is optimized by adjusting the electron energy to maximize $^{99m}Tc$ photo-production. The NRF reaction rate for $^{99m}Tc$ is first optimized without considering the photon attenuations such as photo-atomic interactions and self-shielding due to the NRF resonance itself. The change in energy spectrum and intensity due to the photo-atomic reactions has been quantified using the MCNP6 code and then the NRF self-shielding effect was considered to obtain the spectrums that include all the attenuation factors. Simulations show that when a $^{99}Tc$ target is irradiated at an intensity of the order $10^{17}{\gamma}/s$ for 30 h, 2.01 Ci of $^{99m}Tc$ can be produced.

• 해양환경안전학회지
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• 제27권1호
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• pp.81-87
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• 2021

제주해역은 많은 상선 및 어선들이 항해를 하고, 자망, 트롤 등 다양한 어구를 활용하여 어로활동을 하고 있다. 그 동안 해양폐기물 수집은 주로 제주도 해안 및 연안해역에서 시행되고 있으나, 연근해 해역에서 발생되는 해양폐기물 발생에 대한 수집 및 연구가 미미하였다. 이에 본 연구는 제주대학교 실습선을 이용하여 제주도 북서해역에 침전한 해양폐기물을 수거하고 각 폐기물별로 관련 선박의 항적을 분석하였다. 또한 일정 구역 및 선박 체류시간별로 얼마나 많은 해양폐기물을 투기하고 있는지 분석하기 위해 선박자동식별장치 항적데이터를 활용하여 대상해역에 선박이 체류한 시간을 추출하여, 어선업종별로 1 ㎢ 단위구역에서 시간당 해양폐기물 발생양을 분석하였다. 분석 결과 연근해 해역은 어선기인 폐어구가 대다수였으며, 그중 자망 및 통발 어구가 많은 비율을 차지하고 있었다. 본 연구에서 단위구역에서 시간당 해양폐기물 발생량은 자망어업이 평균 0.94 kg, 통발어업이 3.49 kg, 저인망어업이 0.10 kg, 연승어업이 0.11 kg, 기타어업이 0.02 kg으로 산출되었다. 이 결과를 활용하여 향후 연근해 수중환경 정화시 해양폐기물 발생이 높은 해역위주로 해양폐기물 수거가 가능할 것이다.