• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.4146-4158
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• 2023

This paper proposes a combined plastic and creep constitutive model of A533B1 pressure vessel steel to simulate progressive deformation of nuclear pressure vessels under severe accident conditions. To develop the model, recent tensile test data covering a wide range of temperatures (from RT to 1,100 ℃) and strain rates (from 0.001%/s to 1.0%/s) was used. Comparison with experimental data confirms that the proposed combined plastic and creep model can well reflect effects of temperature and strain rate on tensile behaviour up to failure. In the companion paper (Part II), the proposed model will be used to simulate OECD lower head failure (OLHF) test data.

• Tribology and Lubricants
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• v.36 no.3
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• pp.117-123
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• 2020

In this study, the effect of the pre-mild wear mode test condition on the subsequent severe wear behavior of carbon steel has been investigated when the wear mode is varied according to the sliding speed change during sliding contact. Two sliding speeds of 0.3 m/s and 3 m/s for the mild wear mode test have been chosen and a sliding speed of 1 m/s for the severe wear mode test. A mild wear mode test at two different sliding speeds has been carried out during the severe wear mode test and total sliding distance of the mild wear mode test has been changed at this time. As a result, it could be found that the wear rate of carbon steel under the severe wear mode test after performing a pre-mild wear mode test is significantly reduced, compared with that before performing. However, its wear rate was slightly higher than that under the mild wear mode test. Oxides produced during the pre-mild wear mode test have been found to play a significant role in reducing the wear rate under the subsequent severe wear mode test. In particular, it was found that the effect of a pre-mild wear mode test performed at the sliding speed of 3 m/s has more rapid and the reduction in the wear rate was greater than thst at the sliding speed of 0.3 m/s.

• Tribology and Lubricants
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• v.13 no.1
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• pp.21-27
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• 1997

The friction and wear behavior of undulated surfaces made of tin base babbit are examined experimentally at the low sliding speed with severe loading condition. Steel is used as counterface disk material under pin-on-disk type sliding condition. Undulated surfaces can improve the friction and wear properties under dry friction condition since undulated surfaces trap wear particles in their cavities and prohibit wear particles from agglomerating. However, under boundary lubrication condition, friction and wear properties of undulated surfaces are inferior to those of flat surfaces. It is shown that land width and the ratio of wear volume to cavity volume are the most important factors in friction behavior of undulated surfaces under dry friction condition, and there exists optimum land width minimizing friction and wear of undulated surfaces.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.135-139
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• 2002

Most of all the mechanical devices are becoming more high-speed and high-power as well as their used condition being more polluted. So, it is necessary for these devices to equip cooling system to overcome that kind of severe using condition. In this study, corrosion test was carried out in distilled and tap water for the investigation on the corrosion characteristics of Al-alloy that is using as material for radiator.

• Journal of Chest Surgery
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• v.26 no.2
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• pp.160-162
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• 1993

Pulmonary lymphangiomyomatosis is rare but extremely interesting condition caused by progressive widespread smooth muscle proliferation in the perilymphatic regions throughout the lungs. The patient was a 25-year-old female. She had angiofibromas in the face, and angiomyolipoma in the left kidney which was removed 5 years earlier. Three years ago she started having severe dyspnea with bilateral pneumothoraces. Treatment was initiated with bilateral closed thoracotomies followed by open thoracotomy through median sternotomy and lung biopsy, which revealed the diagnosis of pulmonary lymphangiomyomatosis. Recurrence of pneumothorax was treated by repeated chemical pleurodesis with tetracycline. She has been in good condition during medroxyprogesterone administration for 3 years.

• Korean Journal of Veterinary Research
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• v.42 no.3
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• pp.429-436
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• 2002

Hydrocepbalus may be an acquired or a congenital condition. We have studied the macroscopic and microscopic changes in the hydrocephalus of an inbred Sprague-Dawley rat at postnatal week 8. The animal suspected with the hydrocephalus showed clinical syndromes such as depression, severe ataxia, eye abnormalities, dome-shaped head, and persistent fontanelle. With the postmortem examination, the suspected animal was clearly revealed as a severe internal hydrocephalus. In this animal, severe ventriculomegaly was limited to the third and lateral ventricles, and cortical thining was most apparent in the parieto-occipital region. With the routine histological examination, brain tissue showed aqueductal obstruction, thinning of the cerebral cortex, severe ependymal damage, subependymal edema, damage of choroid plexus of fourth ventricle, enlarged cortical vessels, and expanded ventricles. Aqueductal obstruction was observed with the appearance of simple stenosis at the level of rostral colliculus. Subsequently, the other structures of brain such as septal nucleus, caudate nucleus, and hippocampus etc. were abnormally reconstructed by hydrocephalus. This study suggests that the hydrocephalus can be taken place by primary aqueductal obstruction and this type of hydrocephalus is classified as uncommunicating type. Though the mechanism of aqueductal obstruction is not clear, the morphological studies of this case may be helpful for the further study of hydrocephalus.

• Journal of Ocean Engineering and Technology
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• v.21 no.2 s.75
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• pp.35-41
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• 2007

In general, coastal damage is mostly occurred by the action of complex factors, like severe water waves. If the maximum storm surge height combines with high tide, severe water waves will overflow coastal structures. Consequently, it can be the cause of lost lives and severe property damage. In this study, using the numerical model, the storm surge was simulated to examine its fluctuation characteristics at the coast in front of Noksan industrial complex, Korea. Moreover, the shallow water wave is estimated by applying wind field, design water level considering storm surge height for typhoon Maemi to SWAN model. Under the condition of shallow water wave, obtained by the SWAN model, the wave overtopping rate for the dike in front of Noksan industrial complex is calculated a hydraulic model test. Finally, based on the calculated wave-overtopping rate, the inundation regime for Noksan industrial complex was predicted. And, numerically predicted inundation regimes and depths are compared with results in a field survey, and the results agree fairly well. Therefore, the inundation modelthis study is a useful tool for predicting inundation regime, due to the coastal flood of severe water wave.

• Nuclear Engineering and Technology
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• v.46 no.3
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• pp.373-380
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• 2014

Safety-related parameters are very important for confirming the status of a nuclear power plant. In particular, the reactor vessel water level has a direct impact on the safety fortress by confirming reactor core cooling. In this study, the reactor vessel water level under the condition of a severe accident, where the water level could not be measured, was predicted using a fuzzy neural network (FNN). The prediction model was developed using training data, and validated using independent test data. The data was generated from simulations of the optimized power reactor 1000 (OPR1000) using MAAP4 code. The informative data for training the FNN model was selected using the subtractive clustering method. The prediction performance of the reactor vessel water level was quite satisfactory, but a few large errors were occasionally observed. To check the effect of instrument errors, the prediction model was verified using data containing artificially added errors. The developed FNN model was sufficiently accurate to be used to predict the reactor vessel water level in severe accident situations where the integrity of the reactor vessel water level sensor is compromised. Furthermore, if the developed FNN model can be optimized using a variety of data, it should be possible to predict the reactor vessel water level precisely.

• Tuberculosis and Respiratory Diseases
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• v.60 no.2
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• pp.235-238
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• 2006

Exogenous lipoid pneumonia (ELP) is an uncommon condition resulting from aspiration or inhalation of vegetable, animal or mineral oil. It results in foreign body type inflammatory reaction of the lung and can show various clinical presentations from asymptomatic incidental finding to severe pneumonia leading to acute respiratory failure. Although many cases have been reported, severe ELP requiring steroid or whole lung lavage for treatment is rare. We report a case of 51-year old man with esophageal cancer who developed severe ELP following ingestion of large dose shark oil (Squalene) and successfully treated with prednisolone.

• The Korean Journal of Quaternary Research
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• v.9 no.1
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• pp.43-60
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• 1995

The Kanweoldo Deposit in the Cheonsoo Bay western coast of Korean Peninsula is considered to be influenced by severe freezing condition under cold humid environment of the last glacial age. The evidence of severe freezing in the some upper part of the fine-grained Kanweoldo Deposit is characteristically irregular wavy la-mellar structure with the interval of 2∼8mm. In particular lamina show very compacted fabrics composed of rounded or spheroidal discrete aggregates covered by silt caps. Such laminar structure and associated micro-fabrics might owe to soil freezing such as ice segregation in lens form cryophoresis pressure from growing ice and disturbance by frost-creep. Furthermore pedogenesis of cold-humid type such as gleyzation or peseudo-gleyzation also might af-fect the kanweoldo Deposit in the priod of severe cold-humid cli-mate of the Wrm. The Kanweoldo sediment and organic remnant(16,708 B.P. with error limit of 250 years) affected by severe cryogenic activities sug-gest that the paleoclimate of Late Wrm in Korea might be so cold and humid as to engender the cryogenic structure in subaerial silty and sandy silt deposits.