• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.555-567
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• 2013

A finite element formulation for a Rayleigh-damped Bernoulli-Euler beam subjected to support motions, which accompanies quasi-static rigid-body motion, is presented by using the quasi-static decomposition method. Moving support beam elements, one of whose nodes is coincident with the moving support, are developed to represent the effect of a moving support. Statically determinate beams subjected to support motions can be modeled successfully by using moving support elements. Examples of cantilever and simply-supported beams subjected to support motions are illustrated, and the numerical results are compared with the analytical solutions. The comparison shows good agreement.

• Journal of the Society of Disaster Information
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• v.12 no.1
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• pp.1-9
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• 2016

Local wall thinning elbow due to the water flow is one of the main degradation phenomenon in carbon steel pipe of plant system. The API579 code of FFS (fitness for service) used in the chemical plant gives a guideline to protect local wall thin problem in a straight pipe, but it does not include an elbow. In this study, the locally wall thinned elbow, which is considered an extrados or intrados wall thinned elbow, was carried out considering in-plane or out-plane bending using FEM (finite element method) analysis, and some of results were also compared with the experimental data. The results could give the structure integrity assessment to protect the local wall thinned elbow.

• Journal of fish pathology
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• v.24 no.3
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• pp.213-223
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• 2011

Among wild marbled sole, Pleuronectes yokohamae caught in west coastal area, Chungnam, tumor-bearing fish were found. Parasites and pathogenic bacteria were not detected and CPE was not observed. Using the light microscope, the epidermal layer of wild P. yokohamae was significantly thickened compared to the normal skin. The lesion was formed papillary folds. Hypertropical epithelial cells revealed karyolysis, marked nucleolus and cloud swelled cytoplasm. In the epidermal layer of the lesion, X-cell that is characterized by oval and small pale nucleus and prominent nucleolus was observed. Dermal layer had newly formed vessels. The size of mucous cell in the papilloma lesion was significantly increased compared to the normal. In this study, no pathogens were found, so future works for finding cause of the papilloma in the P. yokohamae are needed.

• Journal of fish pathology
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• v.24 no.3
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• pp.205-211
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• 2011

All of the crucian carp, Carassius auratus and 50% of common carp. Cyprinus carpio examined in this study were infected with the leeches, Limnotrachelobdella sinensis. Especially, the infection of C. carpio with L. sinensis was the first report in Korea. The gill of C. auratus showed increased hydrophic degeneration of epithelial cell in the filament, blood congestion, hyperplasia of epithelial cell in the filament and lamellae. In the SEM observation, gill filament was transformed to the cylinder form by the lamellae fusion. The lamellae surface showed degeneration, fragmentation of microridges. The extracellular cartilaginous matrix of the filaments was exposed by the collapse of epidermal layer. In the 18S rRNA analysis of L. sinensis, the relationships among these groups are not clear and not concord with their morphological classification.

• Fire Science and Engineering
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• v.29 no.4
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• pp.26-32
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• 2015

Carbon dioxide principally extinguishes fires by smothering, but an acceptable amount of extinguishing agent is needed. To assure the performance of carbon dioxide systems in Korea, computer programs certified by NEMA are being applied in system design. But the design errors can occur because the geometry of a model test facility is not the same as that of the actual fire area. Since the discharge rate tends to vary considerably with the flow pattern in a pipe, an on-site discharge test is necessary to ensure the performance of the system, especially with low pressure carbon dioxide. Technical standards for carbon dioxide systems do not give detailed guidelines for discharge tests at present. Based on comparative analysis of standards and practical tests, this paper suggests a methodology for on-site discharge tests.

• Journal of radiological science and technology
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• v.41 no.4
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• pp.339-344
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• 2018

Humans received an exposure dose of 2.4 mSv of natural radiation per year, of which the contribution of spacecraft accounts for about 75%. The crew of the aircraft has increased radiation exposure doses based on cosmic radiation safety management regulations There is no reference to air passengers. Therefore, in this study, we measured the radiation exposure dose received in the sky at high altitude during flight, and tried to compare the radiation exposure dose received by ordinary people during flight. We selected 20 sample specimens, including major tourist spots and the capital by continent with direct flights from Incheon International Airport. Using the CARI-6/6M model and the NAIRAS model, which are cosmic radiation prediction models provided at the National Radio Research Institute, we measured the cosmic radiation exposure dose by the selected flight and departure/arrival place. In the case of exposure dose, Beijing was the lowest at $2.87{\mu}Sv$ (NAIRAS) and $2.05{\mu}Sv$ (CARI - 6/6M), New York had the highest at $146.45{\mu}Sv$ (NAIRAS) and $79.42{\mu}Sv$ (CARI - 6/6M). We found that the route using Arctic routes at the same time and distance will receive more exposure dose than other paths. While the dose of cosmic radiation to be received during flight does not have a decisive influence on the human body, because of the greater risk of stochastic effects in the case of frequent flights and in children with high radiation sensitivity Institutional regulation should be prepared for this.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.4
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• pp.352-358
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• 2011

The presence of ISKNV-like viruses in various freshwater ornamental fish species imported from Asia was confirmed by polymerase chain reaction(PCR) amplification of the ATPase(adenosine triphosphatase) gene. Interestingly, molecular analyses of the Open Reading Frame 25(ORF25) region of these isolates based on the ISKNV(Infectious spleen and kidney necrosis virus) genome revealed the presence of various repetitive sequences. ORF25 repeat sequence length had no effect on cumulative mortality of rock bream Oplegnathus fasciatus challenged with tissue homogenates of infected pearl gourami, Trichogaster leeri; silver gourami, Trichogaster microlepis; blue gourami, or Trichogaster trichopterus. All isolates induce cumulative mortalities after 12 days of infection, confirming that ORF25 polymorphism did not affect the pathogenicity of ornamental fish megalocytiviruses that cross infect rock bream, a seawater fish. Also, no statistically significant differences in spleen index or viral copy number in infected tissues was detected between isolates with varying ORF25 repeat sequence lengths. However, further studies are necessary to fully characterize the functional characteristics of these polymorphisms in megalocytivirus disease in ornamental fishes.

• Fire Science and Engineering
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• v.18 no.4
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• pp.64-71
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• 2004

This paper describes the result of the pump room fire analysis of the nuclear power plant using CFAST fire modeling code developed by NIST. The sensitivity studies are performed over the input parameters of CFAST: the constrained or unconstrained fire, Lower Oxygen Limit (LOL), Radiative Fraction (RF), and the opening ratio of the fire doors. According to the results, a pump room fire is the ventilation-controlled fire, so it is adequate that the value of LOL is 10% which is also the default value. It is anlayzed that the Radiative Fraction does not affect the temperature of the upper gas layer. It is appeared that the integrity of the cable located at the upper layer is maintained except for the safety pump at the fire area and the Conditional Core Damage Probability (CCDP) is 9.25E-07. It seems that CCDP result is more realistic and less uncertain than that of Fire Hazard Analysis (FHA).

• Journal of the Korea Concrete Institute
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• v.17 no.5 s.89
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• pp.735-742
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• 2005

The purpose of this study was to evaluate the salt water resistance of concrete depending on various types of cement. In this regard, 5 types of concrete were selected and their strength, void ratio and chloride ion diffusion characteristics were tested, and mutual correlation were analyzed. From the test results, the compressive strength and void ratio of concrete which using Type V cement was as good as Type I cement at long-term ages but the chloride diffusion coefficient of Type V cement was larger than Type I cement. And the concrete replacing some portion of the Type I cement with fly ash was superior in the cases of compressive strength, void ratio and the resistance of chloride ion permeation compared to the Type I cement with the lapse of ages. On the other hand, the compressive strength, the void ratio and the chloride diffusion coefficient of the concrete all indicated high levels of the correlation coefficient and the coefficient of determination regardless of the type of cement.

• Journal of Environmental Science International
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• v.25 no.8
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• pp.1107-1114
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• 2016

This research, sponsored by the Korean Ministry of Environment in 2014, was the first epidemiological study in Korea that investigated the health impact assessment of radon exposure. Its purpose was to construct a model that calculated the annual mean cumulative radon exposure concentrations, so that reliable conclusions could be drawn from environment-control group research. Radon causes chronic lung cancer. Therefore, the long-term measurement of radon exposure concentration, over one year, is needed in order to develop a health impact assessment for radon. Hence, based on the seasonal correction model suggested by Pinel et al.(1995), a predictive model of annual mean radon concentration was developed using the year-long seasonal measurement data from the National Institute of Environmental Research, the Korea Institute of Nuclear Safety, the Hanyang University Outdoor Radon Concentration Observatory, and the results from a 3-month (one season) survey, which is the official test method for radon measurement designated by the Korean Ministry of Environment. In addition, a model for evaluating the effective annual dose for radon was developed, using dosimetric methods. The model took into account the predictive model for annual mean radon concentrations and the activity characteristics of the residents.