• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.217-223
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• 1998

This study was performed to figure out water consumption of the twisted sweet pepper in a greenhouse. Obtained results are as follows; 1. The ambient temperature was nearly same as the normal year, while the average air temperature and the relative humidity in the green house were little bit higher than those of the outside condition. The transparency of the greenhouse roof was approximately 50%. The total amount of rainfall during the irrigation period was 1,040㎜ which is 350㎜ higher than 1997 during the same period. 2. In case of pot cultivation, as the saturation ratio was increased, the aeaf area and plant height and yield were also increased. The yield from the field cultivation was higher than the average yield from the pot cultivations which are treated by three levels of saturation ratio. 3. The variation of daily consumptive use of the twisted sweet pepper was very large in it's range. In case of the pot cultivation, as the saturation was increased, the daily and the total consumptive use were increased. 4. The daily consumptive use was strongly correlated with the ambient temperature, while it was weakly correlated with the relative humidity and solar radiation. 5. There were close correlation between plant environment; leaf area, plant height and yield, and consumptive use. As the saturation ratio was increased, the correlation between those plant factors and consumptive use was getting stronger.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.10
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• pp.1177-1186
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• 2009

High temperature steam pipes of thermal power plant are subject to a severe thermal range and usually operates well into the creep range. Cyclic operation of the plant subjects the piping system to mechanical and thermal fatigue damages. Also, poor or malfunctional supports can impose massive loads or stress onto the piping system. In order to prevent the serious damage and failure of the critical piping system, various inspection methods such as visual inspection, computational analysis and on-line piping displacement monitoring were developed. 3-dimensional piping displacement monitoring system was developed with using the aluminum alloy rod and rotary encoder sensors, this system was installed and operated on the high temperature steam piping of "Y" thermal power plant successfully. It is expected that this study will contribute to the safety of piping system, which could minimize stress and extend the actual life of critical piping.

• Korean Journal of Materials Research
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• v.14 no.10
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• pp.743-748
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• 2004

Modified Ni/YSZ cermets for high temperature electrolysis were synthesized by the direct ball milling of Ni and YSZ powder. The ball milling was carried out in dry process and in ethanol with varying milling time. While the dry-milling decreased the average size from 65 to $80{\mu}m$, the wet-milling decreased the average size down to $10{\mu}m$. In addition, very fine particles less than $0.1{\mu}m$ were observed in the wet-milling condition. The subsequent process of cold-pressing and sintering at $900^{\circ}C$ for 2 h did not affect the particle size of dry-milled powder. The electrical conductivity of the dry-milled Ni/YSZ cermet showed the value of $5{\times}10^{2}\;S/cm$ and this value was increased to $1.4{\times}10^{4}\;S/cm$ after the sintering at $900^{\circ}C$ for 2 h.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.3
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• pp.130-136
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• 2014

The present study is performed to set up the framework of cooling tower performance predictions. The performance of mechanical forced draft cooling tower is directly related to the state of a nuclear power plant system, such as the condenser and evaporator. The main parameters related to the state of systems are as follows : wet bulb temperature, dry bulb temperature and absolute humidity. The performance evaluation of cooling tower must be considered at the power plant design. In this study, the toolkit developed by the American Cooling Tower Industry association (CTI) has been used for the framework construction. In order to validate the framework, it is being applied to the cooling tower constructed for the U.S. Nuclear Power Plant. The test results have shown good agreements with the cold water temperature on the cooling tower performance curves provided by manufacturers.

• Research in Plant Disease
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• v.29 no.4
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• pp.399-404
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• 2023

Agricultural activities and the number of farms in the subarctic regions have been increasing annually after the coronavirus disease 2019 pandemic to achieve food self-sufficiency. Potatoes are vulnerable to soft rot bacteria at all stages of production, storage, and transportation. A novel bacterium, Pseudomonas sp. N3-W, isolated from Alaska tundra soil, grows at 5-25℃ and produces extracellular protease(s). N3-W caused necrotic spots (hypersensitivity) in hot pepper leaves and soft rot disease (pathogenicity) in potato tubers. The psychrotolerant N3-W caused significant soft rot symptoms on potatoes at a broad temperature range (5℃, 15℃, and 25℃). In contrast, mesophilic Pectobacterium carotovorum KACC 16999 induced severe rotting symptoms in potatoes at their optimal growth temperature of 15℃ and 25℃. However, it barely produced symptoms at 5℃, which is the appropriate storage and transportation temperature for potatoes. The results of pathogenicity testing imply that psychrotolerant soft rot pathogens from polar regions may cause severe soft rot not only during the crop growing season but also during storage and transportation. Our study indicates the possibility of new plant pathogen emergence and transmission due to the expansion of crop cultivation areas caused by permafrost thawing in response to recent polar warming.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.305-310
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• 2023

Bandiburichodang (BDC) is a new variety of Zea mays L. Total polyphenol content (TPC) assay and quantitative analysis of ferulic acid (FA) were performed to determine the steaming, roasting conditions of BDC kernels that lead to the highest content. TPC levels increased after roasting under all conditions. TPC levels in samples steamed at 115 ℃ for 25 min were 3.157 mg/g before roasted, and increased to 3.825 and 4.739 mg/g after roasting at 160 and 200 ℃, respectively. Whether BDC kernels were roasted was relevant with TPC content. BDC kernels were extracted to perform quantitative analysis of FA. Roasting temperature affected FA content: the higher the temperature, the lower the content. BDC kernels that were steamed at 115 ℃ for 25 min had 0.178 mg/g of FA content before roasting, and levels decreased to 0.132 and 0.115 mg/g after roasting. Under different roasting conditions, FA content decreased 15 to 50%. We hypothesize that this phenomenon is due to a breakdown of phenolic compounds or cell wall disruption.

• Nuclear Engineering and Technology
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• v.53 no.2
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• pp.532-548
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• 2021

Nuclear power plants contain several monitoring systems that can identify the in-vessel phenomena of a severe accident (SA). Though a lot of analysis and research is carried out on SA, right from the development of the nuclear industry, not all the possible circumstances are taken into consideration. Therefore, to improve the efficacy of the safety of nuclear power plants, additional analytical studies are needed that can directly monitor severe accident phenomena. This paper presents an interacting multiple model (IMM) based fault detection and diagnosis (FDD) approach for the identification of in-vessel phenomena to provide the accident propagation information using reactor vessel (RV) out-wall temperature distribution during severe accidents in a nuclear power plant. The estimation of wall temperature is treated as a state estimation problem where the time-varying wall temperature is estimated using IMM employing three multiple models for temperature evolution. From the estimated RV out-wall temperature and rate of temperature, the in-vessel phenomena are identified such as core meltdown, corium relocation, reactor vessel damage, reflooding, etc. We tested the proposed method with five different types of SA scenarios and the results show that the proposed method has estimated the outer wall temperature with good accuracy.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2005.04a
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• pp.88.1-88.1
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• 2005

• Nuclear Engineering and Technology
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• v.39 no.2
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• pp.95-102
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• 2007

The conceptual design of the MIT modular pebble bed reactor is described. This reactor plant is a 250 Mwth, 120 Mwe indirect cycle plant that is designed to be deployed in the near term using demonstrated helium system components. The primary system is a conventional pebble bed reactor with a dynamic central column with an outlet temperature of 900 C providing helium to an intermediate helium to helium heat exchanger (IHX). The outlet of the IHX is input to a three shaft horizontal Brayton Cycle power conversion system. The design constraint used in sizing the plant is based on a factory modularity principle which allows the plant to be assembled 'Lego' style instead of constructed piece by piece. This principle employs space frames which contain the power conversion system that permits the Lego-like modules to be shipped by truck or train to sites. This paper also describes the research that has been conducted at MIT since 1998 on fuel modeling, silver leakage from coated fuel particles, dynamic simulation, MCNP reactor physics modeling and air ingress analysis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.614-622
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• 2010

The goal of this paper is to develope the control program based on model which can be applied to 1000MW class coal fired thermal power plant. 1000MW class power plant has the higher efficiency and lower cost because the steam conditions of the ultra super-critical process are higher than them of the previous power plants in temperature and pressure. The program includes the state variable controls which have the desired characteristics for the higher temperature and pressure. The program had been developed successfully using advanced process control. The simulation results using the new control program showed the better performance and safer control than them of the previous control program and we could verify the application possibility of the new program for the actual power plant through the load test, comparison, analysis and tuning.