• Journal of Hydrogen and New Energy
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• v.35 no.3
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• pp.324-335
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• 2024

The container package type sealed water electrolysis production system installs mechanical balance of plant and electrical balance of plant as an integrated unit to enable independent operation within the package module. The auxiliary equipment required to operate the water electrolysis system must be integrated to reduce the installation area and shorten the installation time. At this time, as leak risk factors are placed in a dense space, when a hydrogen gas leak accident occurs, it can have a mutual influence on other adjacent facilities, so it contains various risk factors. In this study, when a gas leak occurs in a container packaged water electrolysis system, possible sources of leakage in the system according to the KS C IEC 60079-10-1:2015 and KGS GC101 standards were identified, and the leak rate and leak characteristics were calculated. did. The hazardous area and its range were calculated according to ventilation and dilution characteristics. In order to optimize ventilation characteristics, design of experiment was used to analyze the influence to evaluate the adequacy of ventilation, and overseas ventilation standards were analyzed and compared. In addition, the optimal ventilation structure and characteristics of the container packaged water electrolysis system were presented according to the results of the experimental design method.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.1
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• pp.7-17
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• 2016

The present study experimentally considers dynamic performance of large floating wave-offshore hybrid power generation platform in extreme conditions. In order to evaluate the motion performance of the large floating hybrid power generation platform, 1/50 scaled model was manufactured. A mooring line was also manufactured, and free-decay and static pull-out tests were carried out to check the mooring model. A mooring line table was introduced to satisfy the water depth, and environmental conditions were checked. Motion responses in regular waves were measured and complicated environmental conditions including wave, wind, and current were applied to see the dynamic performance in extreme/survival conditions. Maximum motion and acceleration were judged following the design criteria, and maximum offset and mooring tension were also checked based on the rule. The characteristics of hybrid power generation platform are discussed based on these data.

• Journal of Energy Engineering
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• v.6 no.2
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• pp.176-187
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• 1997

As a way to evaluate the performance of IGCC (Integrated Gasification Combined Cycle) processes, heating values of coal gas as well as plant efficiency were compared for different rank coals and coal feeding methods by employing the static process simulation technique. Performance of the process was compared with coal rank that was varied by three assorted bituminous coals and also by three subbituminous coals, in addition to the two types of feeding techniques, i.e., dry-feeding and slurry-feeding, that are utilized in entrained-bed coal gasifiers. For the verification of the simulation technique, simulated results were compared first with the actual pilot plant data published from Shell and Texaco. The simulation technique was, then, applied to other coals. Result from tests varying coal rank exhibits the trend of improving both heating content of the product gas and plant efficiency with increasing carbon content in coal. The effect of coal rank is more sensitive in slurry-feeding cases compared to the dry-feeding cases. In particular, considering notably lower values in gas heating value and plant efficiency calculated in the slurry-feeding case that uses a subbituminous coal, limited utilization of the slurry-feeding method for subbituminous coals can be expected. From the plant efficiency point of view, dry-feeding method resulted in higher simulated efficiency values by maximum 3% for subbituminous coals and ca. l% for bituminous coals.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.6
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• pp.816-824
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• 2006

This study was conducted to evaluate the shoot height at which the yield and nutritive value of wormwood (Artemisia montana) is optimized in order to provide information on its potential to support animal production (Experiment 1). A second objective was to determine how the essential oil (EO) concentration in wormwood hay and silage differ (Experiment 2). In Experiment 1, Artemisia montana was harvested at five different shoot heights (20, 40, 60, 80 and 100 cm) from triplicate $1.8{\times}1.8m$ plots. Dry matter (DM) yield was measured at each harvest date and the harvested wormwood was botanically separated into leaf, stalk and whole plant fractions and analyzed for chemical composition and in vitro dry matter digestibility (DMD). Values for total digestible nutrients (TDN), digestible energy (DE) and metabolizable energy (ME) were subsequently calculated using prediction equations. Dry matter yields of stalk and whole plant increased linearly (p<0.001) and leaf yield increased quadratically (p<0.01) with shoot height, whereas the leaf/stalk ratio decreased linearly (p<0.001). As shoot height increased, there was a linear increase (p<0.001) in leaf DM, ether extract (EE) and neutral detergent fiber (NDF) contents and a quadratic increase (p<0.05) in leaf acid detergent fiber (ADF) and nitrogen free extract (NFE) contents, and stalk and whole plant DM (p<0.001), organic matter (OM, p<0.01 and p<0.05), NDF (p<0.001 and 0.05) and NFE (p<0.05) contents. However, there were decreases in leaf crude protein content (CP, quadratic, p<0.001) and stalk and whole plant EE content (linear, p<0.001), CP (quadratic, p<0.05) and ash (quadratic, p<0.05) contents. Digestibility of DM and TDN, and DE and ME value in leaves were not affected by increasing shoot height, but these measures linearly decreased (p<0.001) in stalk and whole plant. In Experiment 2, the hay had higher DM and CP concentrations, but lower EE concentration than the silage. Essential oil (EO) content in wormwood silage (0.49 g/100 g DM) was higher (p<0.05) than that in wormwood hay (0.32 g/100 g DM). Wormwood hay contained 25 essentail oils (EO) including camphor (10.4 g/100 g), 1-borneol (11.6 g/100 g) and caryophyllene oxide (27.7 g/100 g), and wormwood silage had 26 EO constituents including 3-cyclohexen-1-ol (8.1 g/100 g), trans-caryophyllene (8.6 g/100 g) and ${\gamma}$-selinene (16.8 g/100 g). It is concluded that the most ideal shoot height for harvesting wormwood is 60 cm based on the optimization of DM yield and nutritive value. Wormwood silage had a greater quantity and array of EO than wormwood hay.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.845-848
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• 2013

Due to intense climate changes and extreme weather conditions a noticeable decrease has been observed in the growth of certain plants. The indoor plant factories would have certain benefits including increase in crop yield, reduction in distribution cost, and maintains the healthy freshness level of the agricultural product. Recently, an artificial light source with optimum wavelength is spot lighted to fulfill the need of light for the indoor plant factories. The energy efficient light emitting diodes (LED) provide the essential light energy for the proper growth of indoor cultivated plants. This work focuses to utilize ubiquitous sensors network(USN) in providing suitable environment for the proper growth of agricultural product inside the indoor plant factory. The proposed system makes use of sensors and actuators, communicating each other through WPAN, ZigBee network. The proposed system obscured the traditional indoor plant factories with easy installation and wireless connectivity of the sensors and actuators along with eliminating the web of wires reducing the initial installation and maintenance cost.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.662-669
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• 2017

This study evaluated the ecotoxicological properties of livestock waste water treated by a LID (Low Impact Development) system, using a mixture of bio-reeds and bio-ceramics as suitable bed media for a subsequent treatment process of a livestock wastewater treatment plant. The relationship between the pollutant reduction rate and the ecotoxicity was analyzed with the effluents from the inlet pilot plant, with vegetated swale and wetlands and the batch type of an infiltration trench. Each pilot plant consisted of a bio process using bio-reeds and bio-ceramics as bed media, as well as a general process using general reeds and a bed as a control group. The results indicated that, after applying the HRT 24 hour LID method, the ecotoxicity was considerably lowered and the batch type pilot plant was shown to be effective for toxicity reduction. The LID method is expected to be effective for water quality management, considering ecotoxicity by not only as a nonpoint source pollution abatement facility but also, as a subsequent treatment process linked with a livestock manure purification facility. It is necessary to take the LID technic optimization study further to apply it as a subsequent process for livestock wastewater treatment.

• Journal of Radiation Industry
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• v.6 no.2
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• pp.189-197
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• 2012

This study was carried out to develop the improved useful mutants for yield or composition of stevia plants using the gamma ray or chemical mutagens treatments. The seeds of stevia 'Suwon No. 11' were irradiated up to 400 Gy of gamma ray. Chemical mutagens were treated on the seeds of the 'Suwon No. 11' using 0.07% colchicine, 10 mM sodium azide, or 10 mM NMU for various durations. The germination rate, and shoot and root growth of seedling were estimated at 30 days after gamma ray irradiation or chemical mutagen treatment, and the plant height, the number of branches, and leaf length and width were examined at 3 months after mutagenesis treatments. In the case of gamma ray treatments, the germination rate and early-stage growth were decreased as the increase of radiation dose, and the 50% lethal dose was found to be 200 Gy. the plant height was decreased as the increase of radiation dose, while the number of branches per plant and leaf length were increased. Leaf shape was modified to the relatively longer one compared to the control, which was identified more apparently at the treatments of higher than 150 Gy. In the treatment of chemical mutagens, the rate of germination and survival were decreased as the increase of incubation time. The 50% lethal dose for germination rate were identified as the conditions of the 15 hours incubation in 0.07% colchicine, the 4 hrs in 10 mM sodium azide, and the 2 hrs in 10 mM NMU, in the three chemical mutagens treatments. Chemical mutagens had no influence on shoot growth, while root growth was increased, especially as the incubation time was extended. The highest root growth occurred in the NMU treatment at 6 hrs incubation time. The plant height was decreased as the increase of incubation time in the chemical mutagens treatments. Among the chemical mutagens, NMU was the most effective to induce the mutants with long-shaped or the least lobed leaves.

• Nuclear Engineering and Technology
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• v.49 no.7
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• pp.1547-1554
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• 2017

VESTA (Verification of Ex-vessel corium STAbilization) and VESTA-S (-small) test facilities were constructed at the Korea Atomic Energy Research Institute in 2010 to perform various corium melt experiments. Since then, several tests have been performed for the verification of an ex-vessel core catcher design for the EU-APR1400. Ablation tests of an impinging $ZrO_2$ melt jet on a sacrificial material were performed to investigate the ablation characteristics. $ZrO_2$ melt in an amount of 65-70 kg was discharged onto a sacrificial material through a well-designed nozzle, after which the ablation depths were measured. Interaction tests between the metallic melt and sacrificial material were performed to investigate the interaction kinetics of the sacrificial material. Two types of melt were used: one is a metallic corium melt with Fe 46%, U 31%, Zr 16%, and Cr 7% (maximum possible content of U and Zr for C-40), and the other is a stainless steel (SUS304) melt. Metallic melt in an amount of 1.5-2.0 kg was delivered onto the sacrificial material, and the ablation depths were measured. Penetration tube failure tests were performed for an APR1400 equipped with 61 in-core instrumentation penetration nozzles and extended tubes at the reactor lower vessel. $ZrO_2$ melt was generated in a melting crucible and delivered down into an interaction crucible where the test specimen is installed. To evaluate the tube ejection mechanism, temperature distributions of the reactor bottom head and in-core instrumentation penetration were measured by a series of thermocouples embedded along the specimen. In addition, lower vessel failure tests for the Fukushima Daiichi nuclear power plant are being performed. As a first step, the configuration of the molten core in the plant was investigated by a melting and solidification experiment. Approximately 5 kg of a mixture, whose composition in terms of weight is $UO_2$ 60%, Zr 10%, $ZrO_2$ 15%, SUS304 14%, and $B_4C$ 1%, was melted in a cold crucible using an induction heating technique.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.2
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• pp.51-60
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• 2003

Rice, which occupies about 60% of the farmland in Korea, is a staple crop in Asia. It not only absorbs $CO_2$ from the atmosphere, but also emits carbon in a form of CH$_4$. It has a potential role in the global budget of greenhouse gases because of its relative contributions of carbon absorption and emission associated with changing hydrologic cycle. To better understand its current and future role, seasonal variations of energy and $CO_2$ exchange in this critical ecosystem need to be quantified. The purpose of this study was to measure, document and understand the exchange of energy and $CO_2$ in a typical rice paddy in Korea throughout the whole growing season. Since late April of 2002, we have conducted measurements of energy and $CO_2$ exchange in a rural rice paddy at Hari site, one of the Korea regional network of tower flux measurement (KoFlux). After the quality control and gap-filling, the observed fluxes were analyzed in the context of micrometeorology and biophysics. $CO_2$ and energy exchanges varied significantly with land cover changes (e.g., plant growth stages), in addition to changes in weather and climate conditions. This study, reporting first direct measurement of energy and $CO_2$ exchange over a rice paddy in Korea, would serve as a useful database as one of the reference sites in AsiaFlux and FLUXNET.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.11
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• pp.1757-1763
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• 2010

Flywheel energy storage system (FESS) is defined as a high speed rotating flywheel system that can save surplus electric power. The FESS is proposed as an efficient energy storage system because it can accumulate a large amount of energy when it is operated at a high rotating speed and no mechanical problems are encountered. The FESS consists of a shaft, flywheel, motor/generator, bearings, and case. It is difficult to simulate rotor dynamics using common structure simulation programs because these programs are based on the 3D model and complex input rotating conditions. Therefore, in this paper, a program for the FESS based on the 2D FEM was developed. The 2D FEM can model easier than 3D, and it can present the multi-layer rotor with different material each other. Stiffness changing of the shaft caused by shrink fitting of the hub can be inputted to get clear solving results. The results obtained using the program were compared with those obtained using the common programs to determine any errors.