• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.164-169
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• 2018

A detailed fatigue evaluation procedure was developed to mitigate the excessive conservativeness of the conventional environmental fatigue evaluation method for the pressurizer spray line elbow of domestic new nuclear power plants. The pressurizer spray line is made of austenitic stainless steel, which is relatively sensitive to the environmentally assisted fatigue, and has a low degree of design margin in terms of environmentally assisted fatigue due to the thermal stratification phenomenon on the pipe cross section as a whole or locally. In this study, to meet the environmental fatigue design requirements of the pressurizer spray line elbow, the new environmental fatigue evaluation has been performed, which used the ASME Code NB-3200-based detailed fatigue analysis and the environmental fatigue correction factor instead of the existing NB-3600 evaluation method. As a result, the design requirements for environmentally assisted fatigue were met in all parts of the pressurizer spray line elbow including the fatigue weakened zones by thermal stratification.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.33-38
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• 2009

Energy loss from windows accounts for large scores of heating and cooling loads also in energy saving apartments that is reduced over 30% of total energy consumption. Movable reflective insulations, insulation shutters, blinds, insulated shades are used to reduce energy loads from windows. In this study, energy saving performance of insulated shades was simulated by control methods. According to installation of insulated shades, heating loads were decreased about $10.5{\sim}11.3%$, and cooling loads are decreased about $11.0{\sim}15.5%$ on an energy saving apartment. The heating peak load was reduced about 9.5% by insulated shades, but the cooling peak load is hardly ever decreased. Because in the condition of cooling peak load, latent cooling loads accounts for large score of cooling loads. Difference of the energy loads by a schedule control method and an outdoor detection control was no more than 5% for a base model. In the case of insulated shades with automatic control system, simple time schedule control system would be more efficient than outdoor detection control system that should use several sensors.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.4
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• pp.276-283
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• 2012

Objectives: This study was conducted to survey the viewpoints on the material safety data sheets(MSDS) training for safety and health managers(SHMs) and workers. Subjects and Methods: A surveillance was made using a self-reported questionnaire for 78 SHMs and 122 workers to survey their viewpoints on the MSDS training. Survey results were analyzed using the SPSS program(Version 12.0 SPSS Inc., USA). Results: The result of the study shows that there are contrasts with the cognition of SHMs' and workers' on the education of MSDS and the program preference for education efficiency of MSDS. Workers were significantly more interested in the MSDS education than the SHMs did. Workers preferred the education program which is easily to be understood, to voluntarily participate on MSDS education, but SHMs did the quiz program. Also we found that the SHMs wanted to learn the education program via the expert(37.3%) rather than education resources(33.3%) which were served by government or relevant agency. In contrast, workers wanted the audio-visual education program, which is mainly consisted of accident cases (33.3%), rather than periodical education program(22.1%). Conclusions: This study showed that effectiveness of MSDS education was associated with the program served by company, and the education program for the voluntary participation of the workers should be made practical and attractive.

• Tribology and Lubricants
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• v.10 no.1
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• pp.14-26
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• 1994

The minimum oil film thickness(MOFT) in the connecting-rod bearing of a 1.5 liter, L-4, gasoline engine is measured up to 5500 rpm and calculated to study the dynamically loaded engine bearing. Short bearing approximation and Mobility method are used for theoretical analysis of oil film characteristics. And cylinder pressure, crank-pin surface temperature and bearing temperature are measured as the input data of theoretical analysis. The MOFT are measured by the total capacitance method(TCM). To improve the reliability of the test results, a reasonable determination method of bearing clearance is introduced and used, and the effects of cavitation and aeration on the test results are neglected. The crankshaft is grounded by means of a slip ring. A scissor type linkage system was developed to measure the MOFT and bearing temperature. The effects of engine speed, load and oil viscosity on the measured and calculated minimum oil film thicknesses are investigated at 1500 to 5500 rpm. From the comparison between the measured and calculated MOFT, it is found that a qualitative similarity exists between them, but in all cases, the measured MOFT are smaller than those calculated.

• International Journal of Fluid Machinery and Systems
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• v.3 no.1
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• pp.58-66
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• 2010

A steam control valve is used to control the flow from the steam generator to the steam turbine in thermal and nuclear power plants. During startup and shutdown of the plant, the steam control valve is operated under a partial flow conditions. In such conditions, the valve opening is small and the pressure deference across the valve is large. As a result, the flow downstream of the valve is composed of separated unsteady transonic jets. Such flow patterns often cause undesirable large unsteady fluid force on the valve head and downstream pipe system. In the present study, various flow patterns are investigated in order to understand the characteristics of the unsteady flow around the valve. Experiments are carried out with simplified two-dimensional valve models. Two-dimensional unsteady flow simulations are conducted in order to understand the experimental results in detail. Scale effects on the flow characteristics are also examined. Results show three types of oscillating flow pattern and three types of static flow patterns.

• Nuclear Engineering and Technology
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• v.49 no.3
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• pp.632-637
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• 2017

Even though the potential for an accident in nuclear power plants is very low, multiple emergency plans are necessary because the impact of such an accident to the public is enormous. One of these emergency plans involves a robotic system for investigating accidents under conditions of high radiation and contaminated air. To develop a robot suitable for operation in a nuclear power plant, we focused on eliminating the three major obstacles that challenge robots in such conditions: the disconnection of radio communication, falling on uneven floors, and loss of localization. To solve the radio problem, a Wi-Fi extender was used in radio shadow areas. To reinforce the walking, we developed two- and four-leg convertible walking, a floor adaptive foot, a roly-poly defensive falling design, and automatic standing recovery after falling methods were developed. To allow the robot to determine its location in the containment building, a bar code landmark reading method was chosen. When a severe accident occurs, this robot will be useful for accident condition monitoring. We also anticipate the robot can serve as a workman aid in a high radiation area during normal operations.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.29-32
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• 2019

The development of Information and Communication Technology facilitates exchange of information and communication between system in ships or between ships and land facilities, thereby improving the efficiency of their work. However, these changes in the working environment of companies and ships increased the likelihood of cyber security incidents occurance like unauthorized access to company and ship systems or infection of malicious code, which results in significant safety, environmental and business damage to company and ships. Therefore, a cyber-risk-based approach was required to identify and respond to an increasing cyber threats. In this paper, the analysis of maritime cyber security status and guidelines for establishment of maritime cyber security system are provided.

• New & Renewable Energy
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• v.19 no.2
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• pp.13-22
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• 2023

With the increased interest in renewable energy, various hydrogen production technologies have been developed. Hydrogen production can be classified into green, blue, gray, and pink hydrogen depending on the production method; each method has different technical performance, costs, and CO₂ emission characteristics. Hence, selecting the technology priorities that meet the company strategy is essential to develop technologically and economically feasible projects and achieve the national carbon neutrality targets. In addition, in early development technologies, analyzing the technology investment priorities based on the company's strategy and establishing investment decisions such as budget and human resources allocation is important. This study proposes a method of selecting priorities for various hydrogen production technologies as a specific implementation plan to achieve the national carbon neutrality goal. In particular, we analyze key performance indicators for technology, economic feasibility, and environmental performance by various candidate technologies and suggest ways to score them. As a result of the analysis using the aforementioned method, the priority of steam methane reforming (SMR) technology combined with carbon capture & storage (CCS) was established to be high in terms of achieving the national carbon neutrality goal.

• Journal of the Korean Institute of Rural Architecture
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• v.24 no.4
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• pp.97-106
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• 2022

During the Japanese colonial period, Japan exploited the entire Korean Peninsula and targeted not only cities but also rural areas. The exploitation of rural area was accelerated with the support of Oriental colonization Company and The countryside was a living scene of direct exploitation. However, most of the research was concentrated in representative port cities such as Kunsan, which transports logistics such as rice and grains. There was insufficient research on how Japanese entered the country, how Korean were plundered, and the rural villages that were the target of exploitation. The contents of hi-exploitation were also historical and historical humanities such as colonial land ownership and farm management, and the spatial structure of the existing traditional villages were insufficiently investigated. Hwaho-ri, Shin Taein-eup, Jeollabuk-do, centered on Yongseo Village, there are many traces of farm houses, hospitals, employee residences, schools, churches, and Oriental colonization Company This study aims to study what changes traditional rural villages have brought by the Japanese colonial rule, centering on Hwaho-ri Village.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.5
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• pp.83-92
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• 2015

Recently, Co-working that is a new trend of working and Co-working Space that create Co-working are increasing rapidly around the centers to support start-up such as one-person creative companies. However, the business centers located outside Seoul are not enough to recognize knowledge and skill for operating Co-working Space. Therefore, this study selects the big research issue which is "The recognition and case of co-working & application to co-working space" and the small research issue that is "Co-working Space operation activities" for qualitative research by using in-depth interview to managers of one-person creative company business centers. As a result, on the perspective of the big research issues, they understood Co-working concept, but the Co-working case was made by manager's effort without voluntary participation of the users. Co-working Space is important to recognize as a space for interaction and exchange information but was used only as a sharing space. And on the perspective of the small research issues, 'Space & Interior', 'Alliance and Partnership' and 'Community and Communication' show low awareness and activities. So, we suggest improvement plans through the case of best practices. This study is valuable, it could be a help to adapt and improve to Co-working Space in one-person creative company business center for creation of performance by Co-working.