• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.40 no.6
• /
• pp.613-622
• /
• 2020

The South Korean government plans for a 37 % reduction in CO2 emissions against business as usual by 2030. Subsequently, the Ministry of Land, Infrastructure and Transport declared a 26.9 % reduction target in greenhouse gas emissions from buildings by 2020 and established the Green Standard for Energy and Environmental Design (G-SEED) to help improve the environmental performance of buildings. Construction companies often work with consulting firms to prepare for G-SEED certification. In the process, owing to inefficient data sharing and work connections, it is difficult to achieve economic efficiency and obtain certification. The objective of this study was to develop an economic model to assist contractors in achieving the required G-SEED scores for materials and resources. To do this, we automated the process for material comparison and selection on the basis of an analysis of actual consulting data, and developed a model that selects material alternatives that can meet the required scores at a minimum cost. Information on materials is input by applying a genetic algorithm to the optimization of alternatives. When the model was applied to actual data, the construction cost could be lowered by 79.3 % compared with existing methods. The economical material selection model is expected to not only reduce construction costs for owners desiring G-SEED certification but also shorten the project design time.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.28 no.3
• /
• pp.95-120
• /
• 2023

Methane (CH₄) is a key greenhouse gas in the atmosphere with 85 times greater greenhouse potent relative to carbon dioxide (CO₂). The atmospheric concentration of CH₄ is rapidly increasing due to the intensive usage of CH₄ and the thawing of the cryosphere. Additionally, with the current warming of ocean water, the dissociation of gas hydrates, an ice-like compound and the largest reservoir of CH₄ on Earth, is expected to occur, resulting in the release of CH₄ from the seafloor into the overlying water and atmosphere. Moreover, bottom water hypoxia is another concern that potentially introduces greenhouse gases into the atmosphere. With ongoing global warming and eutrophication, the size and duration of bottom water hypoxia are rapidly increasing. These low-oxygen conditions would relocate the redox zone shallower in sediment or in the water column, causing the release of CH₄ into the atmosphere and thereby intensifying global warming. However, there exists a gap in the understanding of CH₄ dynamics including its generation in relation to bottom water hypoxia. Therefore, this review article aims to understand the relationship between CH₄ and bottom water hypoxia and to draw attention to CH₄ investigation in Korea.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.9 no.4
• /
• pp.177-186
• /
• 2005

The latest concrete structure has showed that the deterioration of durability has been increased by the damage from salt, carbonization, freezing & thawing and the others. Therefore, the measures for the concrete which has deteriorated durability have been taken. Among them, it has been often used that surface treatment which cuts off the deterioration factors of durability by protecting the surface of concrete. However, troubles such as fracture and rupture in the repair layer have been reported as time goes by due to the difference between the organic repair material like epoxy and concrete properties. Researchers have been developing the repair material which can cut off the deterioration factors of durability such as $CO_2$ gas, chloride ion and water by making the formation of concrete elaborate through the reaction with calcium ion when the surface improving agent is coated on the concrete. The main ingredient of that is inorganic substance which is the same as the concrete property. This study was evaluated the surface improving agent for permeability, watertightness, air-permeability, chemical resistance and elution resistance. As a result, it has been reported that the surface improving agent improves watertightness and air-permeability by penetration more than 10mm within concrete. Therefore, it is concluded that the surface improving agent developed in this research prevents deterioration of concrete durability when it is coated on the concrete structure.

• Journal of Astronomy and Space Sciences
• /
• v.22 no.2
• /
• pp.125-138
• /
• 2005

S152 is a small bright emission nebula located in the Perseus arm. Its optical diameter corresponds to 1.5 pc for an adopted distance 3.5 kpc. However, S152 is a part of a giant molecular cloud complex, which consists of several dense cores, containing active star-forming sites, and well aligned arm-like features. We analyzed the FCRAO $^{12}CO(J=\;1{\to}0)$ Outer Galaxy Survey data in this region to study the kinematical structure of this region, which resembles a big "scorpion". We found that there exist three different velocity components, about -54.5, -50.4, -48.8 km $s^{-1}$, depending on the position of the "scorpion". There also exist velocity gradients of 0.21 km $s^{-1}pc^{-1}$ and 0.16 km $s^{-1}pc^{-1}$ through the whole extent of the "scorpion". Interestingly, these two velocity gradients show an opposite direction with each other. It is likely that the velocity structure of this region may result from the mergence of different gas clouds, and the interaction with the SNR 109.1-1.0 occurred later, mostly at the region around the "head of the scorpion" only.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.10
• /
• pp.1081-1089
• /
• 2005

In order to examine the application feasibility of Orimulsion fuel in a commercial boiler using heavy fuel oil, a numerical and experimental research efforts have been made especially to figure out the fundamental combustion characteristics of this fuel in a small-scale boiler. One of the notable combustion features of Orimulsion fuel is the delayed appearance of flame location with the flame shape of rather broad distribution, which is found experimentally and confirmed by numerical calculation. This kind of flame characteristics is considered due to the high moisture content included inherently in the process of Orimulsion manufacture together with micro-explosion by the existence of fine water droplets. In order to investigate the effect on the combustion characteristics of Orimulsion, a series of parametric investigation have been made in terms of important design and operational variables such as injected amount of fuel, types of atomization fluid, and phonemenological radiation model employed in the calculation, etc. The delayed feature of peak flame can be alleviated by the adjustment of the flow rate of injected fuel and the generating features of CO, $SO_2$ and NO gases are also evaluated in the boiler. When the steam injection as atomizing fluid is used, the combustion process is stabilized with the reduced region of high flame temperature. In general, the calculation results are physically acceptable and consistent but some refinements of phenomenological models are necessary for the better resolution of pollutant formation. From the results of this small-scale Orimulsion boiler, it is believed that a number of useful information are obtained with the working computer program for the near future application of Orimulsion fuel to a conventional boiler.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.25 no.2
• /
• pp.56-61
• /
• 2015

The effects of the growth temperature on the properties of a-plane GaN epi-layer on r-plane sapphire by HVPE were studied, when the constant V/III ratio and the flow rate of HCl for the Ga source channel was fixed at 10 and 700 sccm, respectively. Additionally the effects of V/III ratios for source gasses were studied when growth temperature and the flow rate of HCl for the Ga source channel was fixed at $1000^{\circ}C$ and 700 sccm, respectively. As the growth temperature was increased, the values of Full Width Half Maximum (FWHM) for Rocking curve (RC) of a-plane GaN (11-20) epi-layer were decreased and thickness of a-plane GaN epi-layer were increased. As V/III ratios were increased at $1000^{\circ}C$, the values of FWHM for RC of a-plane GaN (11-20) were declined and thickness of a-plane GaN epi-layer were increased. The a-plane GaN (11-20) epi-layer grown at $1000^{\circ}C$ and V/III ratio = 10 showed the lowest value FWHM for RC of a-plane GaN (11-20) for 734 arcsec and the smallest dependence of Azimuth angle for FWHM of (11-20) RCs.

• KSBB Journal
• /
• v.21 no.1 s.96
• /
• pp.34-41
• /
• 2006

The aim of this study is the development of biological removal process of methyl ethyl ketone (MEK) in odor gas, which is generated from the waste food recycling process. To develop the removal process of odor gas, MEK, the selection of proper biofilter support was carried out. When the biofilter equipment was passed by synthetic odor gas composed of 250 ppm of MEK, the maximum removal was achieved to $586.6g-MEK/m^3\;hr$ for polypropylene fibril as support. Under the same experimental conditions, the maximum removal in polyurethane support was obtained to $359.7 g-MEK/m^3\;hr$. Finally, the maximum removal in volcanic stone support was $56.2g-MEK/m^3\;hr$.

• Journal of the Korea Concrete Institute
• /
• v.17 no.4 s.88
• /
• pp.489-498
• /
• 2005

Recently, the deterioration of concrete structures have been increased by the damage from salt, carbonization, freezing & thawing and the others. Therefore, the measures for the deterioration of concretes have been taken. Among them, it has been often used that surface treatment which cut off the deterioration factors of durability by protecting the surface of concrete. The water proof and repair materials for concrete mainly use organic materials such as epoxy, these materials excel in intial bonding force and resistance to chemical agents. But they cause difference in the modulus of elasticity and the rate of shrinkage and expansion of concrete, and thus result in such problems as scaling and spatting in the progress of time. Therefore in this study it develop the performance Improving agent of concrete surface that can block a deterioration cause such as $CO_2$ gas, chloride ion and water from the outside and enhance waterproofing ability by reinforcing the concrete surface when applying it to concrete structures.

• Horticultural Science & Technology
• /
• v.18 no.1
• /
• pp.18-21
• /
• 2000

This study was carried out to investigate the MA response of fresh lemongrass (Cymbopogon citratus) depending upon film sources and storage temperatures. The fresh weight loss was significantly lower at 5 and $0^{\circ}C$ than those of higher temperatures. And ceramic $80{\mu}m$ film (CE 80) was more effective in preventing weight loss than CE40. The contents of $CO_2$ and ethylene were much higher in CE 80 wrapping than those in CE 40 ones. Rapid accumulation of $CO_2$ was observed at high storage temperature. However, the ethylene content during whole storage period was higher at $0^{\circ}C$ than those at $5^{\circ}C$, but the level of ethylene was remained below 1ppm and did not adversely affected to lemongrass quality. The treatment of CE 80 at $5^{\circ}C$ was most effective on keeping visual quality and chlorophyll content. The storage durations were up to 48 days at $5^{\circ}C$ and 35 days at $0^{\circ}C$, respectively. Results indicated that CE 80 at $5^{\circ}C$ is an optimal condition for MA storage of lemongrass.

• Journal of Climate Change Research
• /
• v.6 no.3
• /
• pp.233-241
• /
• 2015

In 2014, the United Nations Framework Convention on Climate Change (UNFCCC) agreed to submit the Intended Nationality Determined Contributions (INDCs) at the conference of parties held in Lima, Peru. Then, the South Korean government submitted the INDCs including GHGs reduction target and reduction potential on July, 2015. The goal of this study is to predict GHGs emission and to analyze reduction potential in agricultural sector of Korea. Activity data to estimate GHGs emission was forecast by Korea Agricultural Simulation Model (KASMO) of Korea Rural Economic Institute and estimate methodology was taken by the IPCC and guideline for MRV (Measurement, Reporting and Verification) of national greenhouse gases statistics of Korea. The predicted GHGs emission of agricultural sectors from 2021 to 2030 tended to decrease due to decline in crop production and its gap was less after 2025. Increasing livestock numbers such as sheep, horses, swine, and ducks did not show signigicant impact the total GHGs emission. On a analysis of the reduction potential, GHGs emission was expected to reduce $253Gg\;CO_{2-eq}$. by 2030 with increase of mid-season water drainage area up to 95% of total rice cultivation area. The GHGs reduction potential with intermittent drainage technology applied to 10% of the tatal paddy field area, mid-drainage and no organic matter would be $92Gg\;CO_{2-eq}$. by 2030.