• Journal of Ocean Engineering and Technology
• /
• v.13 no.2 s.32
• /
• pp.90-98
• /
• 1999

Boiler high-temperature pipelines such as main steam pipe, header and steam drum in fossil power plants are degraded by creep damage due to severe operationg conditions like high temperature and high pressure for an extended period time. Such material degradation lead to various component faliures causing serious accidents at the plant. Conventional measurement techniques such as replica method, electric resistance method, and hardness test method have such disadvantages as complex preparation and measurement procedures, too many control parameters, and therefore, low practicality and they were applied only to component surfaces with good accessibility. In this study, both artificial creep degradation test using life prediction formula and frequency analysis by ultrasonic tests for their preparing creep degraded specimens have been carried out for the purpose of nondestructive evaluation for creep damage which can occur in high-temperature pipelline of fossil power plant. As a result of ultrasonic tests for crept specimens, we confirmed that the high frequency side spectra decrease and central frequency components shift to low frequency bans, and bandwiths decrease as increasing creep damage in backwall echoes.

• Journal of the Ergonomics Society of Korea
• /
• v.25 no.3
• /
• pp.85-96
• /
• 2006

Main control room(MCR) man-machine interface(MMI) design of advanced nuclear power plants(NPPs) such as APR(advanced power reactor)-1400 can be validated through performance-based tests to determine whether it acceptably supports safe operation of the plant. In this work, plant performance, personnel task, situation awareness, workload, teamwork, and anthropometric/physiological factor are considered as factors for the human performance evaluation. For development of measures in each of the factors, techniques generally used in various industries and empirically proven to be useful are adopted as main measures and some helpful techniques are developed in order to complement the main measures. Also the development of the measures is addressed based on the theoretical background. Finally we discuss the way in which the measures can be effectively integrated and then HUPESS(HUman Performance Evaluation Support System) which is in development based on the integrated way is briefly introduced.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2009.05b
• /
• pp.93-96
• /
• 2009

This study is to examine a change of quality and a material performance of fiber reinforced cement composite for mass production. It is necessary to make Strain-hardening cementitious composite(SHCC) by batcher plant for ready-mixed concrete and use the performance of SHCC which made based on laboratory level. This study makes a comparative performance of press and mechanics that is the property of Strain-hardening by direct tension. In case of making by batcher plant. This experiment has demonstrated that even if it takes long after being mixed small and compared with the one which made based on laboratory, it has a tendency to be dissatisfied with fiver's dispersion and lower its performance of Strain-hardening. The reason why the material performance of SHCC for mass production went down is through SHCC that mixed sometimes matrix's viscosity and fiber's dispersion.

• Journal of the Korean Society of Combustion
• /
• v.18 no.3
• /
• pp.44-53
• /
• 2013

In this study, the economic evaluation for imported coals was conducted for power plant based on thermo-dynamical performance analysis. The number of coal types considered was 1,755 imported by five power generation companies in Korea during the 2010-2012. The higher heating value (HHV) of the coals ranged 4,000-6,500 kcal/kg, mostly sub-bituminous. The 1D thermo-dynamical performance modeling was performed for a 500 MWe standard power plant using PROATES code. It was founded that the low rank coals had negative effects on the plant efficiency mainly due to the increased heat loss by moisture, hydrogen and flue gas. Based on the performance analysis, the economic performance of the coals was evaluated. The apparent price of low-rank coals tended to be significantly lower than design coal; for example, the unit price of coal with a HHV of 4,000 kcal/kg was 57% of the reference coal having 6,080 kcal/kg. Considering the negative effects leading to a decrease in the thermal performance, heating value compensation, and increased parasite load, the corrected unit cost for the coal with 4,000 kcal/kg was 90.7% of the reference coal. Overall, the cost saving by imported coals was not high as expected.

• Journal of the Korean Society of Safety
• /
• v.22 no.6
• /
• pp.35-40
• /
• 2007

As a way of improving the safety of the chemical facilities, the risk based-inspection(RBI) was executed for the facilities of the applied petrochemical plant using KS-RBI Ver. 3.0 program developed based on the API-581 based resource document(BRD). From an evaluation result of KS-RBI program, we could find the evaluation of the process safety management(PSM) for the applied plant, risk of the applied process, risk of static facilities and pipes, and the demage mechanism of the facilities. Also, we could suggest a proper inspection plan(frequency and method of inspection) using the calculated risk and the status of the facilities. Therefore, the applied plant could be achieved a reduced inspection cost by an extension of inspection frequency, improved productivity, improved reliability of the facilities, and a computerized history management.

• Animal cells and systems
• /
• v.14 no.3
• /
• pp.225-236
• /
• 2010

We compared the composition of phospholipid fatty acids (PLFA) to assess the microbial community structure in the soil and rhizosphere community of non-transgenic watermelons and transgenic watermelons in Miryang farmlands in Korea during the spring and summer of 2005. The PLFA data were seasonally examined for the number of PLFA to determine whether there is any difference in the microbial community in soils from two types of watermelons, non-transgenic and transgenic. We identified 78 PLFAs from the rhizosphere samples of the two types of watermelons. We found eight different PLFAs for the type of plants and sixteen PLFAs for the interaction of plant type and season. The PLFA data were analyzed by analysis of variance separated by plant type (P<0.0085), season (P<0.0154), and the plant type${\times}$season interaction (P<0.1595). Non-parametric multidimensional scaling (NMS showed a small apparent difference but multi-response permutation procedures (MRPP) confirmed that there was no difference in microbial community structure for soils of both plant types. Conclusively, there was no significant adverse effect of transgenic watermelon on bacterial and fungal relative abundance as measured by PLFA. We could reject our hypothesis that there might be an adverse effect from transgenic watermelon with our statistical results. Therefore, we can suggest the use of this PLFA methodology to examine the adverse effects of transgenic plants on the soil microbial community.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.89.2-90
• /
• 2003

Potato late blight, caused by Phytophthora infestans, is one of the important diseases in potato cultivation areas. Though the incidence of late blight was depend on the inoculums and climatic condition In each fields, the foliar blight was reached to 100％ under the severe disease pressure condition in 2003. Outbreak of foliar blight was concentrated from May and July and evaluation of ten fungicides to control of late blight was made at Daekwallryoung area in potato fields. Based on the company recommendation, those fungicides were applied by a sprayer at the recommended rates on a weekly application schedule. Effect of ten fungicides on foliar blight was based on area under disease progress curve (AUDPC). Across all fungicides was reduced by 77％ in AUDPC and dimethomorph was reduced by 92％ in AUDPC during the same period, respectively. Those fungicide were inhibited the mycelial growth of isolate with different rate in chemical amended medium and several fungicides were completely limited the growth of isolate.

• Korean Journal of Agricultural Science
• /
• v.49 no.3
• /
• pp.655-666
• /
• 2022

We assessed the persistence of eight major cruciferous crops-leaf mustard, oilseed rape, cabbage, broccoli, cauliflower, Chinese cabbage, turnip, and radish-growing in the field. In the first part of our experiment, we tested the viability of seeds that had been buried at two different soil depths for up to 16 months. We then broadcast seeds over the soil surface and left them undisturbed to investigate the survivorship of the resultant plants over two years. Seed viability was significantly affected by plant taxa and burial depth, but not substantially affected by the duration of burial. Although seeds of leaf mustard had the greatest viability among all crops examined here, the viability rates were significantly lower at 2 cm depth than at 15 cm. Seeds of leaf mustard, oilseed rape, broccoli, turnip, and Chinese cabbage remained viable throughout the 16-month period. A study of plant demography revealed that only leaf mustard and oilseed rape succeeded in producing seeds and overwintering in the undisturbed field. However, neither of those species competed well with other plants long-term and their overall growth and survival rates declined during the evaluation period. In addition, insect herbivory severely decreased the growth of all of these crops. Our results suggest that populations of leaf mustard and oilseed rape do not tend to persist in the field for more than a few years without disturbance and external seed inputs.

• Journal of Power System Engineering
• /
• v.5 no.1
• /
• pp.11-20
• /
• 2001

Super-critical type steam power plant, which operates with steam pressure above the super-critical point, has a good reputation recently and is adopted as a new standard of the Korean Electric Power Corporation. The reason for the good reputation lies in it's superior power efficiency. However, the field data of the new power plant for the verification of it's performance are still insufficient, and more empirical data are needed to acquire technologies on the effective operation of it. In this study, the authors analyzed the field test data on power efficiencies got in a super-critical type steam power plant, and evaluated the excellency of the new plant by comparing the efficiency data with the one got in a conventional sub-critical type steam power plant.

• Journal of Veterinary Clinics
• /
• v.20 no.3
• /
• pp.364-368
• /
• 2003

Cytogenetic and hematological analysis was performed in peripheral blood from the cattle associated with abnormal delivery around nuclear power plant area. The frequency of micronuclei (MN) in peripheral blood lymphocytes from cattle was used as a biomarker of radiobiological effects resulting from exposure to environmental radiation. An estimated dose of radiation was calculated by best fitting linear-quadratic model based on the radiation-induced MN data over the range from 0 Gy to 4 Gy from the bovine lymphocytes with in vitro irradiation. MN rates in live malformed calf, dams of malformed calves and other cattle living in the same barn from the regions around nuclear power plant, and cattle in control area were 9/1000, 10.8/1000, 13.3/1000 and 10.0/1000, respectively. There were no significant differences in MN frequencies and hematological values between the cattle associated with abnormal delivery around nuclear power plant area and those of control area. This study indicates that the congenital abnormalities near nuclear power plant seemed to be caused by other aetiology.