• Journal of the Korean Institute of Gas
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• v.25 no.4
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• pp.27-35
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• 2021

Recently, as a solution to the sharp drop in "power reserve ratio", it is being converted to a microgrid that enables bi-directional transmission and distribution. A microgrid is composed of a small-scale distributed power supply and a load. As a representative technology of distributed power generation, there is a Micro Combined Heat and Power system applied to homes and buildings. In this study, a safety standard was developed by dividing the power generation system, cooling system, lubrication system, and exhaust system to derive safety standards for a small gas engine power generation system with a gas consumption less than 232.6kW (200,000 kcal/h). In the case of the power generation system, a filter was installed and the system was stopped by detecting gas leakage and abnormalities in engine speed or output and the cooling system is stipulated to stop the system in case of insufficient cooling water or overheating. The lubrication system monitors the pressure and temperature of the lubricating oil and stops the system when an abnormality occurs, and the exhaust gas emission concentration regulation value was specified in accordance with domestic and foreign standards. Through the results of this study, it is judged that the safety of the gas engine power generation system can be improved and it can contribute to the commercialization of products.

• Journal of Animal Science and Technology
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• v.63 no.5
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• pp.1126-1141
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• 2021

Recent evidence has shown that methionine (Met) supplementation can improve milk protein synthesis under hyperthermia (which reduces milk production). To explore the mechanism by which milk protein synthesis is affected by Met supplementation under hyperthermia, mammary alveolar (MAC-T) cells were incubated at a hyperthermic temperature of 42℃ for 6 h in media with different concentrations of Met. While the control group (CON) contained a normal amino acid concentration profile (60 ㎍/mL of Met), the three treatment groups were supplemented with Met at concentrations of 10 ㎍/mL (MET70, 70 ㎍/mL of Met), 20 ㎍/mL (MET80, 80 ㎍/mL of Met), and 30 ㎍/mL (MET90,90 ㎍/mL of Met). Our results show that additional Met supplementation increases the mRNA and protein levels of BCL2 (B-cell lymphoma-2, an anti-apoptosis agent), and decreases the mRNA and protein levels of BAX (Bcl-2-associated X protein, a pro-apoptosis agent), especially at an additional supplementary concentration of 20 ㎍/mL (group Met80). Supplementation with higher concentrations of Met decreased the mRNA levels of Caspase-3 and Caspase-9, and increased protein levels of heat shock protein (HSP70). The total protein levels of the mechanistic target of rapamycin (mTOR) and the mTOR signalling pathway-related proteins, AKT, ribosomal protein S6 kinase B1 (RPS6KB1), and ribosomal protein S6 (RPS6), increased with increasing Met supplementation, and peaked at 80 ㎍/mL Met (group Met80). In addition, we also found that additional Met supplementation upregulated the gene expression of αS1-casein (CSN1S1), β-casein (CSN2), and the amino acid transporter genes SLC38A2, SLC38A3 which are known to be mTOR targets. Additional Met supplementation, however, had no effect on the gene expression of κ-casein (CSN3) and solute carrier family 34 member 2 (SLC34A2). Our results suggest that additional Met supplementation with 20 ㎍/mL may promote the synthesis of milk proteins in bovine mammary epithelial cells under hyperthermia by inhibiting apoptosis, activating the AKT-mTOR-RPS6KB1 signalling pathway, and regulating the entry of amino acids into these cells.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.56-66
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• 2021

In this study, a waste heat recovery system was devised and the performances of components incorporated to recover the heat generated during the processing of aerobic liquid-composting in a livestock manure treatment facility were analyzed. In addition, the availability of recovered heat was confirmed. The heat generated by liquid fermentation in the livestock manure treatment facility was also checked. Experimental temperatures were set at 35, 40, and 45 ℃ based on considerations of the uniformity of aerobic liquid-composting fermentation tank temperature and its operating range (34.5 ~ 43.9 ℃). Recovered heat energies from the combined heat exchanger, which consisted of PE and STS pipes, were 53.5, 65.6, 74.4 MJ/h, The heat pump of capacity 5 RT was heated at 95.6, 96.1, 98.9 MJ/h and the heating COPs of the pump were 4.53, 4.62, and 4.65, respectively. The maximum hot water production capacity of the heat exchanger assuming a fermentation tank temperature of 45 ℃ confirmed an energy supply of 56 360 kcal/day. The heating capacity of the FCU linked to the heat storage tank was 20.8 MJ/h, and the energy utilization efficiency was 96.1%. When livestock manure was dried using the FCU, it was confirmed that the initial function rate was reduced by 50.5 to 45.8 % after drying.

• Journal of the Korean Institute of Gas
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• v.22 no.6
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• pp.76-89
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• 2018

The distribution of the combined heat and power system is active as a solution to the instability of energy supply and environmental pollution caused by continuous industrial development. In Korea, the safety standards for combined heat and power system using a gas engine are insufficient therefore the study on this is needed. In this study, the safety performance and structural/material assessment items of domestic and international standards applied to the combined heat and power system were analyzed to carry out a standardization study on safety performance applicable to 20 kW gas engine combined heat and power system. In addition, the safety performance assessment (plan) of the gas engine combined heat and power system was derived by performing risk analysis and risk assessment using HAZOP. Assessment items include engine ignition systems related to safety performance, piping tight performance, watering and temperature rise performance, combustion performance, electrical efficiency, thermal efficiency, overall efficiency and humidity performance. Gas and water pipes, gas control and shut-off valves, durability, heat resistance, and cold resistance of metal or non-metallic materials related to the structure and materials of the gas engine combined heat and power systems.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.2
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• pp.101-108
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• 2019

This study is analysis of the utilization as a concrete fine aggregate on CGS, a by-product of Integrated coal gasification combined cycle(IGCC). That is, in KS F 2527 "Concrete aggregate," properties of 1~12times to CGS were evaluated, focusing on quality items corresponding to natural aggregate sand(NS) and melted slag aggregate sand(MS). As a result, the distribution of grain shape, safety and expansion were all satisfied with KS standards by physical properties, but the quality was unstable at 7~12times of water absorption ratio and absolute dry density. The particle size distribution was unstable due to asymmetry distribution of coarse particles, and particles were too thick for 7~12times. The passing ratio of 0.08mm sieve was also out of the KS standard at part factor of 7~12times, but chloride content, clay contents, coal and lignite were all satisfactory. Meanwhile, chemical composition was satisfactory except for $SO_3$ in 1~6times, and content and amount of harmful substances were all within the specified value except for F in 7~12times. As a result of SEM analysis, the surface quality and porosity were 7~12times more than 1~6times, and it was the quality was degraded. Therefore, it is necessary to reduce the quality deviation by using separate measures in order to utilize it as concrete aggregate in the future, and if it is premixed with fine quality aggregate, it will contribute positively to solve aggregate supply shortage and utilize circulation resources.

• Journal of agriculture & life science
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• v.52 no.6
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• pp.139-153
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• 2018

This study analyzes the economic effect of rehabilitation and upgrading of reservoirs as a prevented method against natural disasters under recent abnormal weather conditions and dam-break. For the analysis, we divide the purpose of rehabilitation and upgrading of reservoirs into the stable supply of rural water under uncertain weather conditions and the prevention of collapse due to the aging of the reservoir. We measure the economic effect of rehabilitation and upgrading of reservoirs by estimating the resident's willingness-to-pay for the project through Contingent Valuation Method(CVM). The result shows that distributions of willingness-to-pay to prevent natural disasters and dam-break are similar to each other. About 66% of the residents in sample regions are willing to pay for the project. The resident's willingness-to-pay to protect natural disasters and dam-break are 32,250 to 46,147 won and 28,427 to 47,308 won respectively on average for all sample regions. The comparison of willingness-to-pay by type of regions shows that paddy field areas are the highest followed by facility cultivation areas and urban areas. In addition, total expected value of the projects calculated based on the resident's willingness-to-pay for paddy field areas and facility cultivation areas are much larger than actual project costs. This implies that rural residents are fully aware of the importance of the project to prevent natural disasters and dam-break and are willing to pay for additional costs if needed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.496-499
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• 2014

Xe Gas is moved to Target from GPM. It is Used to feasible nuclear reaction from proton of 30MeV Cyclotron being investigated by the Xe-124 Gas target System. This system is divided into four parts. Hardware was constructed by solidworks and Helium Supply is to cool the Havor Foil. Water has the job of cooling down the temperature when Xe Gas is being investigated in the target. Temperature and pressure gauges are attached to be checked easily. GPM(Gas Process Manifold) has the part that prepares to transport Xe Gas. There are Storage Vessel that stores Xe Gas, the cold trap that filters humidity and impurity and lastly storage vessel that temporarily stores Xe Gas. HCS(Helium Circulation System) using the Helium to cleaning and cooling. these parts are used to SIEMENS PLC and Pcvue Program. Because It is more comfortable and easy maintenance.

• The Southeast Asian review
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• v.28 no.1
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• pp.219-261
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• 2018

The conflicts among nations surrounding international rivers are intensifying as worldwide water shortage is getting worse. The Mekong River is a representative trans-boundary river in Southeast Asia shared by six countries, China, Myanmar, Thailand, Laos, Cambodia, and Vietnam. As the economy grows, hydroelectric power has become a major power supply source to meet the increasing power demand of the these countries. However, the construction of dams on the Mekong River is controversial because hydroelectric power in the river upstream has a negative impact not only on the whole river ecosystem but also on residents' life around downstream, in particular. In order to understand the controversy arising from international rivers, it is necessary to take into account different positions of countries sharing it. However, studies on the position of a specific country to Mekong hydropower have been conducted mainly focusing on China and Laos. Therefore, this study tried to study the position of Cambodian government which is located downstream of the Mekong River and is likely to bear costs rather than to gain benefits from hydroelectric power generation. What is the attitude of the Cambodian government to the hydroelectric development of the upper Mekong and what is the reason for that? The study confirmed the Cambodian government's support for dam construction on the Mekong River. It also figured out influential factors on the formation of such a position as follows: 1) economic asymmetry with China, 2) power dependency and geographical asymmetry in Laos, and 3) importance of hydroelectric power in Cambodia.

• Korean Journal of Environmental Biology
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• v.39 no.2
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• pp.225-235
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• 2021

To attain the long-term benefits of forest restoration in North Korea, it is important to present the economic value of reforestation. This study as aimed to evaluate the economic value based on cost-benefit analysis from the ecosystem services perspective. The benefits of reforestation were classified into ecosystem services such as carbon sequestration, water supply, soil erosion control, and disaster risk reduction, and were converted into economic values to calculate comprehensive benefits. In the forest restoration scenario, an "independent forest restoration scenario (IFS)" and a "cooperation-based forest restoration scenario (CFS)" were composed in consideration of recent afforestation performance and forest policy, and the difference in the quantity of afforestation was derived as a scenario despite the same restoration period. In the IFS, it is estimated that over the next two decades, 800 thousand ha of the forest will be restored at a cost of KRW 3,829 billion, resulting in a benefit of KRW 6.87 trillion. The present benefit net value is KRW 3,39 trillion. In the CFS, it is estimated that the benefits of KRW 18,890 billion will be generated by restoring 2.2 million ha of the forest at a cost of KRW 10,053 billion. The present benefit net value is KRW 8,359 billion. In both scenarios, BCR had an economic feasibility value greater than 1, but there was a big difference in the expected benefits. In conclusion, forest restoration can have higher benefits than cost, and its value could be enhanced through forest cooperation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.685-693
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• 2021

This study examined the fire risk of the region in Goyang City using the spatial information data of buildings. The economic damage by industry was assessed according to the probability of fire risk. The study area was confined to Goyang-si, Gyeonggi-do, and the same fire risk reduction rate was applied to each region for the convenience of analysis. The possibility of fire was derived based on the buildings' density and usage in the area by National GIS building-integrated information standard data. The calculation of economic damage by industry in Goyang City due to the fire risk was calculated by combining the Goyang-si industry-related model produced by matching with 30 industrial categories in Input-Output Statistics of Korea Bank and 20 industrial categories in the Goyang-si business survey and the possibility of fire. The basic scenario of production impossibility during six months and business loss due to fire was established and analyzed based on the supply model. The analysis showed that Ilsan-dong-gu, Ilsan-seo-gu, and Deokyang-gu suffered the most economic damage. The "electricity, gas, steam, and water business" showed the greatest loss by industry.