• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 춘계학술대회 논문집
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• pp.59-62
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• 2009

When happen the electrical facilities accident the one's diagnosis system of fault cause was constructed by FMEA method Cable accident cause is given by accident cause that can happen in each one's diagnosis and accident probability value. From the verification of system, the one's diagnosis system agreed well with result that analyzed actual state. Thus, the system is judged to be used effectively examine for accident cause of electrical facilities.

• Nuclear Engineering and Technology
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• 제42권4호
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• pp.365-376
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• 2010

This paper summarizes the results of a Writing Group on the Extension of CFD codes to two-phase flow safety problems, which was created by the Group for Analysis and Management of Accidents of the Nuclear Energy Agency' Committee on the Safety of Nuclear Installations (NEA-CSNI). Two-phase CFD used for safety investigations may predict small scale flow processes, which are not seen by system thermalhydraulic codes. However, the two-phase CFD models are not as mature as those in the single phase CFD and potential users need some guidance for proper application. In this paper, a classification of various modelling approaches is proposed. Then, a general multi-step methodology for using two-phase-CFD is explained, including a preliminary identification of flow processes, a model selection, and a verification and validation process. A list of 26 nuclear reactor safety issues that could benefit from investigations at the CFD scale is identified. Then, a few issues are analyzed in more detail, and a preliminary state-of-the-art is proposed and the remaining gaps in the existing approaches are identified. Finally, guidelines for users are proposed.

• 대한의용생체공학회:의공학회지
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• 제39권6호
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• pp.256-267
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• 2018

The number of items and the market size of the senior-friendly medical devices are rapidly increasing, and it is necessary to come up with a safety management plan for senior-friendly medical devices. We searched and analyzed the definition and policy of senior-friendly medical device, and classified medical device items of the Ministry of Food and Drug Safety, calculated market sizes and manufacturing export import results by classification, and investigated the current state of senior-friendly industry and the fields of its culture. In order to prepare a safety management plan, we reduce the number of items that need to be managed intensively by extracting 69 items for administration, that are substantially harmful to the elderly. As specific safety management plans of items for administration, we propose plans for introductions of readability-enhanced labeling, QR codes for cautions and manuals, universal design mandatory, UDI code system with considering a balanced viewpoint of the industry development.

• Wind and Structures
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• 제20권2호
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• pp.143-168
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• 2015

A numerical model for analyzing air-train-track interaction is proposed to investigate the dynamic behavior of a high-speed train running on a track in crosswinds. The model is composed of a train-track interaction model and a train-air interaction model. The train-track interaction model is built on the basis of the vehicle-track coupled dynamics theory. The train-air interaction model is developed based on the train aerodynamics, in which the Arbitrary Lagrangian-Eulerian (ALE) method is employed to deal with the dynamic boundary between the train and the air. Based on the air-train-track model, characteristics of flow structure around a high-speed train are described and the dynamic behavior of the high-speed train running on track in crosswinds is investigated. Results show that the dynamic indices of the head car are larger than those of other cars in crosswinds. From the viewpoint of dynamic safety evaluation, the running safety of the train in crosswinds is basically controlled by the head car. Compared with the generally used assessment indices of running safety such as the derailment coefficient and the wheel-load reduction ratio, the overturning coefficient will overestimate the running safety of a train on a track under crosswind condition. It is suggested to use the wheel-load reduction ratio and the lateral wheel-rail force as the dominant safety assessment indices when high-speed trains run in crosswinds.

• 한국안전학회지
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• 제33권1호
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• pp.22-27
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• 2018

Many electronic devices are powered by various rechargeable batteries such as lithium-ion recently, and occasionally the batteries undergo thermal runaway and cause fire, explosion, and other hazards. If a battery fire should occur in an electronic device of vehicle and aircraft cabin, it is important to quickly extinguish the fire and cool the batteries to minimize safety risks. Attempts to minimize these risks have been carried out by many researchers but the results have been still unsatisfied. Because most rechargeable batteries are operated on the ion state during charge and discharge of electricity and the combustion of ion state has big difference with normal combustion. Here we focused on the effect of ions including an electron during combustion process. The effects of an ionized fuel on the flame stability and the combustion products were experimentally investigated in the propane jet diffusion flames. The burner used in this experiment consisted of 7.5 mm diameter tube for fuel and the propane was ionized with th ionizer (SUNJE, SPN-11). The results show that toe overall flame stability and shape such as flame length has no significant difference even in the higher ion concentration. However the fuel ionization affects to the pollutant emissions such as NOx and soot. NOx and CO emissions measured in post flame region decreased by fuel ionization, especially high fuel velocity, i.e. high ion density. TGA analysis and morphology of soot by TEM indicates that the fuel ionization makes soot to be matured.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2008년도 정기학술발표대회 논문집
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• pp.794-799
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• 2008

건설 가설재 성능검정제도의 전환기에 들어서 주요 가설재들의 성능검정을 평가하고 선진국의 관련 체계와 비교하여, 안전인증제를 통해 새로운 건설공사용 가설재들의 인증제도를 제안하고자 한다. 현재의 성능검정제도는 1992년에 시작되어 2003년에 재 개정되면서, 3년마다 재 검정을 받도록 하고 있다. 그러나 제조능력을 향상시키지 못하고 업체 간 가격경쟁의 심화로 인해 대부분 같은 형태, 기능의 제품만을 양산하고 있는 실정이다. 기존 성능검정제도에서 안전인증제로의 전환은 보다 체계적인 심사방법 및 품질관리 시스템을 포함하고 있으며, 건설 환경 변화에 대응할 수 있는 다양한 요구사항에 맞춘 규격을 제시할 수 있도록 하고 있다. 안전인증제를 통한 건설공사의 가설재는 의무인증대상과 임의인증대상으로 나누어지며, 종전보다 제품의 품질과 관리 시스템을 향상시켜줄 수 있을 것으로 기대된다.

• Nuclear Engineering and Technology
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• 제42권4호
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• pp.339-364
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• 2010

Following a joint OECD/NEA-IAEA-sponsored meeting to define the current role and future perspectives of the application of Computational Fluid Dynamics (CFD) to nuclear reactor safety problems, three Writing Groups were created, under the auspices of the NEA working group WGAMA, to produce state-of-the-art reports on different aspects of the subject. The work of the second group, WG2, was to document the existing assessment databases for CFD simulation in the context of Nuclear Reactor Safety (NRS) analysis, to gain a measure of the degree of quality and trust in CFD as a numerical analysis tool, and to take initiatives to extend the existing databases. The group worked over the period of 2003-2007 and produced a final state-of-the-art report. The present paper summarises the material gathered during the study, illustrating the points with a few highlights. A total of 22 safety issues were identified for which the application of CFD was considered to potentially bring real benefits in terms of better understanding and increased safety. A list of the existing databases was drawn up and synthesised, both from the nuclear area and from other parallel, non-nuclear, industrial activities. The gaps in the technology base were also identified and discussed. In order to initiate new ways of bringing experimentalists and numerical analysts together, an international workshop -- CFD4NRS (the first in a series) -- was organised, a new blind benchmark activity was set up based on turbulent mixing in T-junctions, and a Wiki-type web portal was created to offer online access to the material put together by the group giving the reader the opportunity to update and extend the contents to keep the information source topical and dynamic.

• Corrosion Science and Technology
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• 제21권6호
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• pp.466-475
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• 2022

Surface oxides and intergranular (IG) oxidation phenomena in Alloy 600 depending on hydrogen concentration were characterized to obtain clear insight into the primary water stress corrosion cracking (PWSCC) behavior upon exposure to pressurized water reactor primary water. When hydrogen concentration was between 5 and 30 cm³ H₂/kg H₂O, NiFe₂O₄ and NiO type oxides were found on the surface. NiO type oxides were found inside the oxidized grain boundary when hydrogen concentration was 5 cm³ H₂/kg H₂O. However, only NiFe₂O₄ spinel on the surface and Ni enrichment were observed when hydrogen concentration was 30 cm³ H₂/kg H₂O. These results indicate that the oxidation/reduction reaction of Ni in Alloy 600 depending on hydrogen concentration can considerably affect surface oxidation behavior. It appears that the formation of NiO type oxides in a Ni oxidation state and Ni enrichment in a Ni reduction (or metallic) state are common in primary water. It is believed that the above different oxidation/reduction reactions of Ni in Alloy 600 depending on hydrogen concentration can also significantly affect the resistance to PWSCC of Alloy 600.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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• pp.28-35
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• 2005

It is now well recognized that the ultimate limit state approach is a much better basis for design and strength assessment of ships and offshore structures since it is difficult to determine the realistic margin of safety using the traditional allowable working stress approach on the basis of linear elastic method solutions together with buckling strengthchecks adjusted by a simple plasticity correction. This paper outlines ALPS theory for ultimate limit state assessment of ship structures. ALPS is a computer software which stands for nonlinear Analysis of Large Plated Structures. Application examples of ALPS program to ultimate limit state assessment of plates, stiffened panels and ship hull girders are presented. A benchmark study is made by a comparison with the ALPS solutions with other methods including class rule formulae, nonlinear finite element methods and experimental results. Future trends on ultimate limit state assessment of ship structures are addresse[1]

• 한국항해학회지
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• 제18권1호
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• pp.63-84
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• 1994

Bareboat Charter Register or Dual Registration under a Demise Charter scheme, does not in fact sanc-tion the alternative use of flags of different states, but rather it authorises the use of the flag of the coun-try where the ship is temporarily flagged only. Bareboat Charter Register is not intended to miselead third party states or persons dealing with the ship in respect of its nationality. Bareboat Charter Register gives a shipwner a more flexible and attractive package, for example mortga-ging facilities might be more attractive in one state because of its stronger laws relating to recovery of liens, whereas the manning requirements might be attractive in another state. By using Bareboat Charter Register, a shipwner/manager can avail himself of both advantage instead of settling for a compro-mise. Ships on a Bareboat charter Register would be subject to the safety, manning and anti-pollution require-ments of the second flag state and would carry that state's right to fly a flag of the original state be withd-rawn and the effect is to suspend the registration during the period of demise charter except in so far as relates to Title transactions.