• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.122.2-122.2
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• 2011

Sulfur hexafluoride ($SF_6$), one of the most potent greenhouse gases, is known as a hydrate former and has been studied at the high pressure up to 1.3 GPa with gas mixtures and with aqueous surfactant. Since we regard $SF_6$ as a potential promoter molecule that can stabilize hydrate structure more effectively compare to the other promoters, further investigation is required to verify the stabilizing ability of $SF_6$ in the hydrate structure. However, the insoluble nature of $SF_6$ in water or gases hinders fine scale analyses. This work discusses the data obtained by using molecular dynamics simulations of structure II (sII) clathrate hydrates containing $SF_6$ and $H_2$. The simulations were performed using the TIP4P/Ice model for water molecule and a previously reported $SF_6$ molecular model (optimized at the pure $SF_6$ single phase system (Olivet and Vega, 2007)), and a $H_2$ molecular model (adapted from the THF+$H_2$ hydrate system (Alavi et al., 2006)). The simulations are performed to observe the stability of $SF_6$ and $H_2$ in the sII clathrate hydrate system with varying temperature and pressure conditions and occupancies of $SF_6$ and $H_2$, which cannot be easily tuned experimentally. We observe that stability of H2 enclathrated in the hydrate structure more affected by the occupancy of $SF_6$ molecules and temperature than pressure, which ranges from 1 to 100 bar.

• Journal of Information Technology Services
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• v.19 no.3
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• pp.139-149
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• 2020

There are now many different commercial weather sensors suitable for smart farms, and various smart farm devices are being developed and distributed by companies participating in the government-led smart farm expansion project. However, most do not comply with standard specifications and are therefore limited to use in smart farms. This paper proposed the connecting structure of operating non-standard node devices in smart farms following standard specifications supporting smart greenhouse. This connecting structure was proposed as both a virtual node module method and a virtual node wrapper method. In addition, the SoftFarm2.0 system was experimentally operated to analyze the performance of the implementation of the two methods. SoftFarm2.0 system complies with the standard specifications and supports non-standard smart farm devices. According to the analysis results, both methods do not significantly affect performance in the operation of the smart farm. Therefore, it would be good to select and implement the method suitable for each non-standard smart farm device considering environmental constraints such as power, space, distance of communication between the gateway and the node of the smart farm, and software openness. This will greatly contribute to the spread of smart farms by maximizing deployment cost savings.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.1
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• pp.49-57
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• 2019

Biomass, a carbon-neutral fuel, has great advantages because it can replace fossil fuels to reduce greenhouse gas emissions. However, due to its low density, high water content, and hydrophilicity, biomass has disadvantages for transportation and storage. To improve these properties, a pretreatment process of biomass is required. One of the various pre-treatment technologies, torrefacion, makes biomass similar to coal through low-temperature pyrolysis. In this study, torrefacion treatment was carried out at 200, 230, 250, 280, and $300^{\circ}C$ for wood pellet, empty fruit bunch (EFB) and kenaf, and the feasibility of replacing coal with fuel was examined. Hygroscopicity tests were conducted to analyze the hydrophobicity of biomass, and its chemical structure changes were investigated using Infrared spectrum analysis. It was confirmed that the hygroscopicity was decreased gradually as the torrefacion temperature increased according to the hygroscopicity tests. The hydrophilicity was reduced according to the pyrolysis of hemicellulose, cellulose, and lignin of biomass.

• Journal of Ocean Engineering and Technology
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• v.37 no.5
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• pp.205-214
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• 2023

As the regulations on greenhouse gas emissions at sea become strict, efforts are being made to minimize environmental pollutants emitted from fossil fuels used by ships. Considering the large sizes of ships in conjunction with securing stable supplies of environment-friendly energy, interest in nuclear energy to power ships has been increasing. In this study, the neutron irradiation that occurs during the nuclear reactor operation and its effect on the structural responses of the stiffened-plate structures are investigated. This is done by changing the material properties of DH36 steel according to the research findings on the neutron-irradiated steels and then performing the structural response analyses of the structures using analytical and finite-element numerical solutions. Results reveal the influence of neutron irradiation on the structural responses of the structures. It is shown that both the strength and stiffness of the structures are affected by the neutron-irradiation phenomenon as their maximum flexural stress and deflection are increased with the increase in the amount of neutron irradiation. This implies that strength and stiffness need to be considered in the design of ships equipped with marine nuclear reactors.

• Elastomers and Composites
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• v.59 no.1
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• pp.8-16
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• 2024

As regulations on greenhouse gas emission have strengthened globally, the demand for improved fuel efficiency in automobiles continues to rise. In response, the tire industry is actively conducting research to improve fuel efficiency by enhancing tire performance. In this study, silica-filled epoxidized natural rubber (ENR)/butadiene rubber (BR) blend compounds were manufactured according to ENR types and silica contents, and their physical properties and vulcanizate structure were evaluated. ENR-50, which has a higher epoxide content than ENR-25, exhibited stronger filler-rubber interaction, resulting in superior abrasion resistance. In addition, because of its high glass transition temperature (T_g), the wet grip performance of ENR-50 improved, even though the rolling resistance increased. Increasing the amount of silica had little effect on the abrasion resistance due to the increase in filler-rubber interaction and decrease in toughness. In addition, ENR-50 exhibited better wet grip performance; however, the rolling resistance increased. The results indicated that truck bus radial (TBR) tire tread compounds can be designed by applying ENR-50 to improve wear resistance and wet grip performance. In addition, by applying ENR-25 and reducing the silica contents improve fuel efficiency.

• Journal of Environmental Health Sciences
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• v.34 no.5
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• pp.343-350
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• 2008

Quantifying greenhouse gas (GHG) emissions in the waste sector is important to evaluating measures for reduction of GHG emissions. To forecast GHG emissions and identify potential emission reduction for GHG emissions, scenarios applied with environmental policy such as waste reduction and structural change of waste treatment were developed. Scenario I estimated GHG emissions under the business as usual (BAU) baseline. Scenario II estimated GHG emissions with the application of the waste reduction policy while scenario III was based on the policy of structural change of waste treatment. Scenario IV was based on both the policies of waste reduction and structural change of waste treatment. As for the different scenarios, GHG emissions were highest under scenarios III, followed by scenarios IV, I, and II. In particular, GHG emissions increased under scenario III due to the increased GHG emissions from the enhanced waste incineration due to the structural change of waste treatment. This result indicated that the waste reduction is the primary policy for GHG reduction from waste. GHG emission from landfill was higher compared to those from incineration. However, the contribution of GHG emission from incineration increased under scenario III and IV. This indicated that more attention should be paid to the waste treatment for incineration to reduce GHG emissions.

• Journal of the Korea Institute of Building Construction
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• v.15 no.1
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• pp.99-105
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• 2015

The building structure has an decisive influence on the environment as it takes over one third part in the energy consumption and greenhouse gas emissions of whole world. Accordingly, every country makes the reduction of greenhouse gas emission compulsory pursuant to Kyoto Protocol of 1997, and Korea government makes an announcement for the improvement of building energy performance in 2014. In this study, the key technology of Energy Saving Environmental-Friendly Building is sorted into 3rd categories, and the analysis of patent trend for patent documents published in Korea, USA, Japan and Europe is carried out. The purpose of this study is to solve the problem of current technology that it cannot show the detailed situation of technique and development strategy of R&D, and to provide a systematic approach for R&D strategy and an exact technology development direction.

• Journal of Environmental Policy
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• v.12 no.2
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• pp.59-86
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• 2013

We analyzed the correlation among the GHG (Greenhouse Gas) emission, energy consumption and economic growth for the 6 specific regions in Korea by using Panel approaches with the test of the EKC hypothesis. We also analyzed the effects of environmental regulation on GHG and economic growth. The results show that by testing of the EKC (Environmental Kuznets Curve) hypothesis model,the effects of the environmental regulation and the structure of industries on GHC emission have a significant result on the regional analysis for SOx. For the NOx and TSP, only TK region passed the turning point of the EKC among the 6 specific regions. And, for the Co, the Central, Honam and the PUKN region passed the turning point of the EKC. This is because GHG emissions by the environment regulation had a weak path effect and also regional industry structures had a weak relation with regional GHG emissions.

• Archives of design research
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• v.13 no.2
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• pp.25-32
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• 2000

The body proportion of a passenger car has been changed by the demand of consumer and the market. Now the interior space proportion on a passenger car become to have the importance as the passenger space and this proportion has been changed as the new models have been developed. It didn't seems to had a unified direction or strategy in the dimensions of the domestic passenger cars on the early models, but they had a specific changes in dimensions on the later models. The proportion of the wheelbase and greenhouse can be calculated into as about 58% and 57% on the compact and sub-compact passenger cars while it is about 56% on mid-size sedan type passenger cars for thier 3-box structure body concept. The overrall proportion of the interior space is bigger on the compact and the sub-compact passenger cars than the mid-size passenger cars as the calculation shows. It can be concluded that the interior space proportion on the compact passenger cars would become larger, which is closed to 60%. And this trend would be appear on the mid-size passenger cars.

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.602-608
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• 2013

Gas hydrate studies are attracting attention of many researchers as an innovative, economic and environmentally friendly technology when it is applied to $CO_2$ capture, transport, and storage. In this study, we investigated whether $CO_2$ hydrate shows the self-preservation effect or not, that is the key property for developing a novel $CO_2$ transport/storage method. Especially the degree of self-preservation effect for $CO_2$ hydrate was studied according to the particle size of $CO_2$ hydrate samples. We prepared three kinds of $CO_2$ hydrate samples varying their particle diameter as millimeter, micron and nano size and measured their change of weight at $-15{\sim}-30^{\circ}C$ under atmospheric pressure during 3 weeks. According to our experimental result, the lower temperature, larger particle size, and compact structure for higher density are the better conditions for obtaining self-preservation effect.