• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.5
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• pp.487-494
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• 2011

The safety valve used in LNG/LNG-FPSO ships plays an important role in maintaining a fixed level of pressure by emitting LNG gas out of the pipes in the LNG piping system. The discharge coefficient is regarded as the most important factor in the valve performance. To satisfy the ship's classification, the discharge coefficient of the safety valve must usually be over 0.8. Despite the importance of understanding the flow phenomena inside the safety valve, the valve design is usually based on experience and experiments. We carried out a computational fluid dynamics (CFD) investigation using the ANSYS-CFX software. We observed the flow phenomena inside the valve and measured the discharge coefficients according to changes in the valve lift, which is the distance between the exit of the nozzle and the lower part of the disc plate. We verified our CFD results for the discharge coefficients using available experimental data.

• Nuclear Engineering and Technology
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• v.9 no.4
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• pp.223-236
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• 1977

An integral computer code has been developed for a mechanical and thermal design and performance analysis of an oxide fuel rod in a pressurized water reactor. The code designated as FROD 1.0 takes into account the phenomena of radial power depression within the pellet, cracking, densification and swelling of the pellet, fission gas release, clad creep, pellet-clad contact, heat transfer to coolant and buildup of corrosion layers on the clad surface. The FROD 1.0 code yields two-dimensional temperature distributions, dimensional changes, stresses, and internal pressure of a fuel rod as a function of irradiation time within a reasonable computation time. The code may also be used for the analyses of oxide fuel rods in other thermal reactors. As an application of FROD 1.0 the behavior of fuel rod loaded in the first core of Go-ri Nuclear Power Plant Unit 1 is predicted for the two power histories corresponding to steady state operation and Codition II of the ANS Classification. The results are compared with the design criteria described in the Final Safety Analysis Report and a discrepancy between these two values is discussed herein.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.500-502
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• 2013

The metallic underground pipes like as metropolitan water supply pipes and gas pipes have a screening effects for power induction phenomenon. Generally, urban area has more metallic underground facilities than rural areas because of its buildings or population density. So we can expect high screening effects for the power induction in urban areas, and we call it the city screening factor. We had carried out the measuring test in urban and rural area respectively 30 sites to prove the actual effects of city screening factor and we derived the numerical value of city screening effects. But we faced with a difficult question that how we can classify the real urban areas or rural areas correctly. In this paper, we introduce the classification method using density of building in test area to apply the city screening factor reasonably.

• Analytical Science and Technology
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• v.9 no.4
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• pp.392-398
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• 1996

Eleven organic chemical substances, tetrachloroethylene, ethyl benzene, p-xylene, o-xylene, isopropyl benzene, n-propyl benzene. 1,2,4-trimethyl benzene, 1,3,5-trimethyl benzene, p-isopropyl toluene. see-butyl benzene, and naphthalene, which have hazardously influenced to human, were extracted from untreated wastewater collected at 26 companies of 8 types industry in the basin of Kwangju stream. Their structures were elucidated by Gas Chromatography/Mass Spectrometry(GC/MS) and in comparison with each standard reagents.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.76-82
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• 1998

Increase of greenhouse gas due to $CO_2$ and CH$_4$ gases would cause the global warming in the atmosphere. According to the global circulation model, it is pointed out in the Okhotsk Sea that the large increase of atmospheric temperature might be occurredin this region by global warming due to the doubling of greenhouse effectgases. Therefore, it is very important to monitor the sea ice extents in the Okhotsk Sea. To improve the sea ice extents and concentration with more highly accuracy, the field experiments have begun to comparewith Airborne Microwave Radiometer (AMR) and video images installed on the aircraft (Beach-200). The sea ice concentration is generally proportional to the brightness temperature and accurate retrieval of sea ice concentration from the brightness temperature is important because of the sensitivity of multi-channel data with the amount of open water in the sea ice pack. During the field experiments of airborned AMR the multi-frequency data suggest that the sea ice concentration is slightly dependending on the sea ice types since the brightness temperature is different between the thin and small piece of sea ice floes, and a large ice flow with different surface signatures. On the basis of classification of two sea ice types, it is cleary distinguished between the thin ice and the large ice floe in the scatter plot of 36.5 and 89.0GHz, but it does not become to make clear of the scatter plot of 18.7 and 36.5GHz Two algorithms that have been used for deriving sea ice concentrations from airbomed multi-channel data are compared. One is the NASA Team Algorithm and the other is the Bootstrap Algorithm. Intrercomparison on both algorithms with the airborned data and sea ice concentration derived from video images bas shown that the Bootstrap Algorithm is more consistent with the binary maps of video images.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.1
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• pp.84-89
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• 2003

The purpose of this study was to evaluate and improve the pre-treatment facility for foodwaste and sewage sludge mixture treatment. The process of foodwaste pre-treatment consists of storage, classification with crushing, and thickening. The effluent of sewage treatment facility was used as the diluting and washing water. The panicle size of foodwaste after pre-treatment was almost under 2mm, the mixture of foodwastes and sewage sludge showed an advantage to the anaerobic digestion. The amount of gas production increased from 0.8ton/day ($CH_4$ : 0.5ton/day) to 3.5ton/day ($CH_4$ : 2.3ton/day) after the anaerobic digestion of the foodwastes and sewage sludge mixture. The amount of sludge cake increased from 11.2ton/day to 21.2ton/day. Therefore, the proper operation of the foodwaste pre-treatment facility was contributed to the efficient anaerobic digestion of foodwaste and sewage sludge mixture treatment.

• Environmental Analysis Health and Toxicology
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• v.13 no.1_2
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• pp.43-53
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• 1998

Ambient air levels of polycyclic aromatic hydrocarbons(PAHs) are of concern because of their potential for adverse health effects including transformation of some of these substances to mutagens and carcinogens by mammalian microsomal enzyme system. Airbone particulate samples were collected by a conventional high-volume sampler and by an Anderson cascade impactor on 2 to 3 days in each month over a period of 1 year at a representative site of the heavy traffic area of Seoul from beptember 1994 to August 1995. Ten individual PAHs in sizable air particulates of each stage of two months were separated and analyzed by gas chromatography/mass spectrometry. As a results of analysis, the gross concentrations of PAHs in the fine and coarse particles were higher in the winter month than in the spring, followed in descending order by in the fall and summer. In a study of dependency of 10 PAHs compounds on size distribution of particles at heavy traffic area found that about 85% of the total PAHs content was associated with particles less than 2.0um (fine particles) in diameter of winter sampling period. while 79% were associated with this size fraction during summer period. In according to the mean concentrations of the 10 PAHs in 7 size classification from < 0.38 to> 10.1, the 'size was the smaller, PAHs concentration was the higher. Thus it was found that PAHs concentration was greatly affected by air particle size. Annual mean benzo(a)pyrene equivalents was 5.88ng/m$^3$ and obtained by applying, toxic equivalency factor developed by Nisbet and Lagoy.

• Journal of Korean Academy of Nursing
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• v.25 no.3
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• pp.457-471
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• 1995

This research was done to promote improvement of practical application of nursing diagnoses and to improve the quality of nursing. The subjects of this research were 156 second year students of C junior nursing college who were giving adult patient care. The nursing diagnoses of 312 reports were analyzed using NANDA. In these case reports only nursing diagnoses were considered, of which there were a total of 982. In the data analysis the 9H of the nursing students' nursing diagnoses matched with 105 NANDA nursing diagnoses, Of these, the most frequent diagnoses were pain(165, 17.48%), anxiety(101, 10.70%), alteration in nutrition(83, 8.79%) , sleep disturbance (67, 7.10%), in activity intolerance (67, 7.10%), ineffective breathing pattern(51,5.40%). The etiology for the students' nursing diagnoses were compared with NANDA's nursing diagnoses by frequency. The most frequent etiology for the nursing diagnoses of pain was a biological etiology(50, 31%), for anxiety, situation crisis(58, 57.43%), for alteration in nutrition, indigesion(23, 27.71%), for sleep disturbance, external etiology(25, 37.32%), for activity intolerance, immobile position(22, 32.84%), for ineffective breathing pattern, pain(35, 68.63%), and for ,impaired physical mobility, pain(31, 65.96%). The most frequent etiology for constipation was inadquate digestion of water and cellulose (16, 34.78%), for fluid volume felicity, loss of body fluid (21, 52.50%), for impaired skin integrity, external etilogy(16, 43.24%), for impaired physical mobility, pain(22, 62.86%) , for knowledge deficits, cognition disturbance(9, 27.27％), for ineffective air way clearance, secretion obstruction(14, 48.27%) , for impaired gas exchange, loss of transport ability of blood oxygen(9, 37.50%) , and for powerlessness, therapy environment (5, 22.73%). The number of nursing diagnoses by pattern was exchange(16), moving(6), feeling(4), choosing(4), relating(3), communication(1), perceiving(1), knowing(1), valuing(1).

• Journal of Navigation and Port Research
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• v.33 no.3
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• pp.175-180
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• 2009

In this study, the basic data were collected for improving the amenity of indoor environment of a super yacht and the performance of indoor environment was analyzed by utilizing measured data during summer period. Through the results of examination, the following conclusions are drawn. 1) It is estimated that, in case of closing the door of Saloon connected with outside, there is little inflow of exhaust gas, but when the door is open, the indoor-air might be polluted so fast. Therefore, it is necessary to make a counter plan about the method of ventilation and amount of ventilation to keep the indoor aerial environment agreeable. 2) It is urgent to conceive countermeasure against engine noise because the noise level of all rooms exceeds 60dB, which is regulation of noise for protecting crew established in ship's classification, during the sailing. 3) State cabin and Guest cabin are super cooled by operating air conditioner exceeding agreeableness extent and it is needed to prevent them.

• Journal of the Korean Wood Science and Technology
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• v.48 no.5
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• pp.591-607
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• 2020

This study was aimed to investigate the changes of chemical composition of the volatile organic compounds (VOCs) emitted from red pine needles in the process of needle abscission or senescence. The VOCs in intact, senescent, and litter red pine needle samples were analyzed by headspace-solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC/MS). And then, multivariate statistical interpretation of the processed data sets was conducted to investigate similarities and dissimilarities of the needle samples. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were used to investigate the dataset structure and discrimination between samples, respectively. From the data preview, the levels of major components of VOCs from needles were not significantly different between needle samples. By PCA investigation, the data reduction according to classification based on the chlorophyll a / chlorophyll b (Ca/Cb) ratio were found to be ideal for differentiating intact, senescent, and litter needles. The following OPLS-DA taking Ca/Cb ratio as y-variables showed that needle samples were well grouped on score plot and had the significant discriminant compounds, respectively. Several compounds had significantly correlated with Ca/Cb ratio in a bivariate correlation analysis. Notably, the litter needles had a higher content of oxidized compounds than the intact needles. In summary, we found that chemical compositions of VOCs between intact, senescent, and litter needles are different each other and several compounds reflect characteristic of needle.