• Journal of Energy Engineering
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• v.23 no.4
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• pp.123-129
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• 2014

ESCO industry should guarantee the energy saving performance with M&V such as developed countries. The application of the ESCO M&V is a necessary condition on energy saving performance. This study recommends a goal, direction, and order of application and suggests selection of M&V between option A, option B, option C, option D by energy conservation technology in Korea, with reference to the examples from IPMVP and applied in US and Japan. In the future, it is needed to study on the guideline for plan report and result report of M&V based on a goal, direction, and selection of M&V option.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.218-220
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• 2008

Urban air quality, including carbon-dioxide emissions, and national energy security are related issues affecting the rail industry and transportation sector as a whole. They are related by the fact that (in the United States) 97-98% of the energy for the transport sector is based on oil, and more than 60% is imported. A fuelcell locomotive combines the environmental advantages of a catenary-electric locomotive with the higher overall energy efficiency and lower infrastructure costs of a diesel-electric. Catenaryelectric locomotives, when viewed as only one component of a distributed machine that includes an electricity-generating plant and transmission lines, are the least energy-efficient locomotive type. The natural fuel for a fuelcell is hydrogen, which can be produced from many renewable energies and nuclear energy, and thus a hydrogen-fuelcell locomotive will not depend on imported oil for its energy supply. This paper proposes a base models of Hybrid fuel cell/IPT railway vehicle power system, the necessary of this research.

• Computers and Concrete
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• v.21 no.5
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• pp.583-592
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• 2018

Today, buildings are exposed to the effects such as explosion and impact loads. Usually, explosion and impact loads that act on the buildings such as nuclear power plants, airports, defense industry and military facilities, can occur occasionally on the normal buildings because of some reasons like drop weight impacts, natural gas system explosions, and terrorist attacks. Therefore, it has become important to examine the behavior of reinforced concrete (RC) structures under impact loading. Development of computational mechanics has facilitated the modeling of such load conditions. In this study, three kinds of RC walls that have different geometric forms (square, ellipse, and circle) and used in guardhouses with same usage area were modeled with Abaqus finite element software. The three configurations were subjected to the same impact energy to determine the geometric form that gives the best behavior under the impact loading. As a result of the analyses, the transverse impact forces and failure modes of RC walls under impact loading were obtained. Circular formed (CF) reinforced concrete wall which has same impact resistance in each direction had more advantages. Nonetheless, in the case of the impact loading occurring in the major axis direction of the ellipse (EF-1), the elliptical formed reinforced concrete wall has higher impact resistance.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.4
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• pp.160-167
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• 2012

This paper is concerned with a particular fracture mechanics parameter ${\Delta}K_{th}$, known as the 'threshold stress intensity range', or 'fatigue threshold'. This threshold ${\Delta}K_{th}$ constitutes, as it were, a hinge between the notion of crack initiation and the notion of crack growth. It has often been thought that, like the endurance limit, it could be an intrinsic criterion of the material. The study was conducted on a SA-508 pressure vessel steel used in the nuclear power industry. This material exhibits a typical threshold effect in the range of the crack growth rates which were determined; that is, below approximately $da/dN=10^{-6}mm/cycle$, the slope of the da./dN versus ${\Delta}K$ curve is almost vertical. The value of ${\Delta}K_{th}$ was determined at a growth rate of $10^{-7}$ mm/cycle according to the ASTM Standard for threshold testing. The fatigue threshold values are in the range 21 $kg/mm^{3/2}$ to 12 $kg/mm^{3/2}$ depending on the stress ratio effect.

• Journal of Energy Engineering
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• v.23 no.2
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• pp.199-206
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• 2014

ESCO industry should guarantee the energy saving performance in response to changes of regulations ESCO. In this point, the application of the M&V is important task on energy saving performance. Therefore, we need to examine the contents of practice for the M&V in developed countries. Between energy user and ESCO, it is important to provide and measure the energy saving performance by guarantee of energy savings performance contracts. After 2013 ESCO business began focusing on guaranteed savings contracts. For this reason, we need to take M&V cases recommended from IPMVP and applied in United States and Japan. Therefore, we should be ready about M&V application for the real conditions of ESCO.

• Journal of the Korean Society of Safety
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• v.29 no.1
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• pp.80-85
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• 2014

A survey of risk perception in South Korea was conducted in 2007 to evaluate relative riskiness of typical industrial and technological risks. This article summarizes the characteristics of risk perception using psychometric analyses. The survey with a sample size of 1,194 reviews the perceived level of 25 risk items in the areas of transportation, chemicals, environment, industry, nuclear power generation, and newly-introduced risks. Six categories of risk identified by a factor analysis show that the level of perceived risk does not correspond to the statistical level. Psychometric analyses including voluntariness, severity, effect manifestation, exposure pattern, controllability, familiarity, benefit and necessity demonstrate that voluntary, familiar and immediate risks are perceived as less risky than involuntary, unfamiliar and delayed ones. Risk communication is critical in reducing the discrepance between objective and subjective level of risk. However, the amount of risk information does not always justify a successful risk communication. A safety policy, risk communication strategy in particular, should take into account diverse dimensions of risk reviewed by psychometric analyses in the study. Social policy toward safety can be improved by integrating policy, human, and social factors as well as technological advances.

• Journal of the Earthquake Engineering Society of Korea
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• v.25 no.4
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• pp.179-189
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• 2021

Conditional spectra (CS) are applied to the seismic fragility assessment of a nuclear power plant (NPP) containment building for comparison with a relevant conventional uniform hazard response spectrum (UHRS). Three different control frequencies are considered in developing conditional spectra. The contribution of diverse magnitudes and epicentral distances is identified from deaggregation for the UHRS at a control frequency and incorporated into the conditional spectra. A total of 30 ground motion records are selected and scaled to simulate the probability distribution of each conditional spectra, respectively. A set of lumped mass stick models for the containment building are built considering nonlinear bending and shear deformation and uncertainty in modeling parameters using the Latin hypercube sampling technique. Incremental dynamic analysis is conducted for different seismic input models in order to estimate seismic fragility functions. The seismic fragility functions and high confidence of low probability of failure (HCLPF) are calculated for different seismic input models and analyzed comparatively.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.70-75
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• 2002

The penetration potential of TIG welding in one single run is limited, though the process itself generates high quality welds with good weld cosmetics. This is one of the main reasons, which has contributed to its development in high duty applications such as those encountered in aeronautical, aerospace, nuclear & power plant applications. For these applications, stainless steels, titanium k nickel based alloys are most often used. As these materials remain very sensible to weld heat input k atmospheric pollution, stringent processing conditions are imposed. For example welding of titanium alloys requires argon shielding of weld zone and for 5 mm thick plates multi-pass runs & filler additions are required. This multi-run operation not only raises the welding cost, but also increases defect risks. In recent years, extensive interest has been raised by the possibility to increase weld penetrations through flux applications & the process is designated ATIG-activated TIG, or FBTIG-flux bounded TIG. The improved welding performance of such flux assisted TIG is related to arc constriction and surface tension effects on weld pool. The research work by authors has lead to the formulation of welding fluxes for stainless steels k titanium alloys with TIG Process. These fluxes are now commercialized & some applications in industry have already been carried out. FBTIG for aluminum has been proposed with silica application for AC mode TIG welding. The paper highlights the fundamentals of flux role in TIG welding and illustrates some industrial applications.

• Corrosion Science and Technology
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• v.12 no.3
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• pp.125-131
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• 2013

The most common pipe wall thinning degradation mechanisms that can occur in the steam and feedwater systems are FAC (Flow Acceleration Corrosion), cavitation, flashing, and LDIE (Liquid Droplet Impingement Erosion). Among those degradation mechanisms, FAC has been investigated by many laboratories and industries. Cavitation and flashing are also protected on the piping design phase. LDIE has mainly investigated in aviation industry and turbine blade manufactures. On the other hand, LDIE has been little studied in NPP (Nuclear Power Plant) industry. This paper presents the development of prediction system for pipe wall thinning caused by LDIE in terms of erosion rate based on air-water ratio and material. Experiment is conducted in 3 cases of air-water ratio 0.79, 1.00, and 1.72 using the three types of the materials of A106B, SS400, and A6061. The main control parameter is the air-water ratio which is defined as the volumetric ratio of water to air (0.79, 1.00, 1.72). The experiments were performed for 15 days, and the surface morphology and hardness of the materials were examined for every 5 days. Since the spraying velocity (v) of liquid droplets and their contact area ($A_c$) on specimens are changed according to the air-water ratio, we analyzed the behavior of LDIE for the materials. Finally, the prediction equations(i.e. erosion rate) for LDIE of the materials were determined in the range of the air-water ratio from 0 to 2%.

• Economic and Environmental Geology
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• v.55 no.3
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• pp.273-280
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• 2022

The purpose of this study is to explore the social perception on geoscience using a big data analysis and to propose a way to enhance people's perception on geoscience. For this, 5,044 media articles including geoscience produced by 54 media companies from January 1, 2010 to April 14, 2022. were analyzed. Big data analyses were applied. The results of analyses are as follows: Media articles consist of key words of research institute, some countries of America, China and Japan, City of Pohang, CEO of KIGAM. And geology, industry, development of mineral resources, environment, energy, nuclear power, and groundwater are highlighted as key words. Also, it is confirmed that topics related to geoscience such as expert, environment and research institute are not individually isolated, but interconnected and linked to topics in the center of future, industry, and global. Based on this result, ways to enhance people's perception on geoscience were discussed.