• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.626-631
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• 2019

The policy-making and technological development for the supply expansion of eco-friendly automobiles has been continuing, but the internal combustion engines still accounts for about 95%. Also, in order to meet the stricter emission regulations of internal combustion engines based on fossil fuels, the proportion of after-treatments for vehicles and (ocean going) vessels is gradually increasing. This study is a basic study for the post-Euro-VI exhaust response of CNG buses, and it is to investigate the basic characteristics according to Pd substitution transition metal effect, catalyst volume effect and space velocity. A catalysts was prepared and tested using a model gas reactor. The NGOC catalyst with 3Pd exhibited the highest catalytic activity with 22% at $300^{\circ}C$, 48% at $350^{\circ}C$ and about 75% at $500^{\circ}C$. 3Co NGOC containing 3wt% of transition metal was excellent in oxidation ability, and it was small in size of 2nm, and the degree of catalyst dispersion was improved and de-NO/CO conversion was high. The volume of the NGOC-LNT-SCR catalyst system was optimal in the combination of 1.5+0.5+0.5 with a total score of 165, considering $de-CH_4/NOx$ performance and catalyst cost. For SV $14,000h^{-1}$, the $CH_4$ reduction performance was the highest at about 20%, while the SV $56,000h^{-1}$ was the lowest at about 5%. If the space velocity is small, the flow velocity decreases and the time remaining in the catalyst volume become long, so that the harmful gas was reduced.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1002-1007
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• 2012

The considerable portion of energy demand has been satisfied by the combustion of fossil fuel and the consequent $CO_2$ emission was considered as a main cause of global warming. As a technology option for $CO_2$ emission mitigation, absorption process has been used in $CO_2$ capture from large scale emission sources. To set up optimal operating parameters in $CO_2$ absorption and solvent regeneration units are important for the better performance of the whole $CO_2$ absorption plant. Optimal operating parameters are usually selected through a lot of actual operation data. However theoretical approach are also useful because the arbitrary change of process parameters often limited for the stability of process operation. In this paper, a theoretical approach based on vapor-liquid equilibrium was proposed to estimate optimal operating conditions of $CO_2$ absorption process. Two $CO_2$ absorption processes using 12 wt% aqueous $NH_3$ solution and 20 wt% aqueous MEA solution were investigated in this theoretical estimation of optimal operating conditions. The results showed that $CO_2$ loading of rich absorbent should be kept below 0.4 in case of 12 wt% aqueous $NH_3$ solution for $CO_2$ absorption but there was no limitation of $CO_2$ loading in case of 20 wt% aqueous MEA solution for $CO_2$ absorption. The optimal regeneration temperature was determined by theoretical approach based on $CO_2$ loadings of rich and lean absorbent, which determined to satisfy the amount of absorbed $CO_2$. The amount of heating medium at optimal regeneration temperature is also determined to meet the difference of $CO_2$ loading between rich and lean absorbent. It could be confirmed that the theoretical approach, which accurately estimate the optimal regeneration conditions of lab scale $CO_2$ absorption using 12 wt% aqueous $NH_3$ solution could estimate those of 20 wt% aqueous MEA solution and could be used for the design and operation of $CO_2$ absorption process using chemical absorbent.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.2
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• pp.197-206
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• 2023

Recently, the international community, including the International Maritime Organization (IMO), has strengthened regulations on air pollution emissions of ships, and eco-friendly ships are actively being developed to reduce exhaust gas emissions. Among them, rotor sail (RS), a wind-assisted ship propulsion system, is attracting attention again. RS is a cylindrical device installed on the ship deck, that generates hydrodynamic lift using a magnus effect. This is a next generation eco-friendly auxiliary propulsion technology, and Enercon company, which developed RS-applied ships, announced that fuel savings of more than 30% are possible. In this study, optimal installation conditions such as RS spacing and arrangement type were selected when multiple RSs were installed on ships. AR=5.1, SR=1.0, and D_e/D was fixed at 2.0 according to the RS arrangement, and the wind direction was considered only for the unidirectional +y-axis. Regarding arrangement conditions, five conditions were set at 3D intervals in the +x-axis direction from 3D to 15D and five conditions in the +y-axis direction from 5D to 25D. C_L, C_D and aerodynamic efficiency (C_L/C_D) were compared according to the square(□) and diamond(◇) shape arrangements. Consequently, the effect of RS on the longitudinal distance was not significantly different. However, in the case of RS flow characteristics according to the transverse distance, the interaction effect of RS was the greatest when the two RSs almost matched the wind direction. In the case of the RS flow characteristics according to the arrangement, notably, when the wind blew in the forward (0°) direction, the diamond (◇) arrangement was least affected by the backward flow between RSs.

• Journal of Navigation and Port Research
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• v.39 no.6
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• pp.439-450
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• 2015

This study objects to find characteristics in chemical tanker markets and to determine optimal chemical tanker size using a total shipping cost in main trading route of asia chemical tankers .Precedent studies of determination of the optimal ship size and case studies about chemical tankers was carried out and tried to introduce a cost model which is applicable to chemical tanker. This study is dependant on numerical analysis and involves scenario analysis to minimize sensitivity of results. This analysis shows as follows. First, 12,000DWT tanker is an optimal size on the 'Far East-Middle East' services, 9,000DWT tanker is a most competitive on the 'Far East-South East Asia' services and 3,000DWT tanker is a most economic size on the 'Inner Far East' services at average market situation. Second, the bigger size of chemical tanker, the more competitive advantage the tanker will obtain when bunker fuel prices rise. Small size ship gets more competitive during bunker prices down. Third, market fluctuation of time charter rate for chemical tanker is less than 20% against its average time charter hire which means less volatile. And tanker's competitiveness per each size is remained mostly same when time charterer rates rise at same proportion. Fourth, bigger size chemical tankers have cost advantages when tanker's quantity of each part cargo increase. And small-sized tanks are more competitive when part cargo scales decrease. For the last, ship's port stay strongly influences on the determination of the optical tanker size. When vessel has shorter port stay, bigger-sized tanker will be more competitive and even can be competitive if applies in short voyage as well.

• Journal of the Korean Applied Science and Technology
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• v.36 no.1
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• pp.324-332
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• 2019

Most countries including Korea and Indonesia have strong policy for implementing biofuels like biodiesel. Shortage of the oil feedstock is the main barrier for increasing the supply of biodiesel fuel. In this study, in order to improve the stability of feedstock supply and lower the biodiesel production cost, the feasibility of biodiesel production using two types of Indonesian tropical crop oils, pressed at different harvesting times, were investigated. R. Trisperma oils, a high productive non-edible feedstocks, were investigated to produce biodiesel by esterification and transesterification because of it's high impurity and free fatty acid contents. the kindly provided oils from Indonesia were required to perform the filtering and water removal process to increase the efficiency of the esterificaton and transesterification reactions. The esterification used heterogeneous acid catalyst, Amberlyst-15. Before the reaction, the acid value of two types oil were 41, 17 mg KOH/g respectively. After the pre-esterification reaction, the acid value of oils were 3.7, 1.8 mg KOH/g respectively, the conversions were about 90%. Free fatty acid content was reduced to below 2%. Afterwards, the transesterification was performed using KOH as the base catalyst for transesterification. The prepared biodiesel showed about 93% of FAME content, and the total glycerol content was 0.43%. It did not meet the quality specification(FAME 96.5% and Total glycerol 0.24%) since the tested oils were identified to have a uncommon fatty acid, generally not found in vegetable oils, ${\alpha}$-eleostearic acid with much contents of 10.7~33.4%. So, it is required to perform the further research on reaction optimization and product purification to meet the fuel quality standards. So if the biodiesel production technology using un-utilized non-edible feedstock oils is successfully developed, stable supply of the feedstock for biodiesel production may be possible in the future.

• Resources Recycling
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• v.31 no.5
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• pp.67-76
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• 2022

The furniture industry has a high possibility to create value-added and a high potential to create new occupations due to the characteristics of the industry, which mainly consists of small and medium-sized enterprises (SMEs). However, the used furniture, which has sufficient reuse value, is also crushed and used as solid refuse fuel (SRF) recently. Besides, the number of waste treatment companies continues to decrease, and it occurs congestion of wood waste. As a way to solve the issue, a business model development of remanufacturing used furniture can be suggested as an alternative due to its high circular economic efficiency. Remanufacturing business including furniture industry creates positive effects in various aspects such as economic, environmental and job creation. In other words, remanufacturing is an effective recycling way to reduce input resources and energy in the production process. The results of economic analysis show that the expected annual revenue from the single worker furniture remanufacturing site was 104 million won which is 3.11 times more than the average income of a single-worker household in Korea and its B/C ratio was estimated about 30 which means high business feasibility. Revenue through furniture remanufacturing also showed 320 times higher than that of SRF production from the perspective of weight. In addition, it is shown that the GHGs reduction from the furniture remanufacturing is 2.2 ton CO₂-eq. per year, which is similar to the amount of GHGs absorption effect of 937 pine trees or 622 Korean oak trees annually. Thus the results of this study demonstrate that it is important to adopt an appropriate recycling method considering the economic and environmental effects at the end-of-life stage.

• Journal of Plant Biotechnology
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• v.37 no.3
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• pp.305-312
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• 2010

During a last decade, the introduced traits in commercialized GM crops have been diversified from a simple trait such as herbicide resistance gene or insectresistance gene which are related to the crop production into more complicated traits such as modification of fatty acid or essential amino acid composition, modified coloring pattern of flower. In addition, it was investigated that several other GM crops bearing more refined traits expected to lead next generation are also awaiting for risk assessment (RA) or under field test for the preparation of RA in the near future. These GM crops include abiotic stress resistance including drought or cold, increased biomass, production of bioethanol or diesel, production of pharmaceuticals or functional materials for industrial. In particular, in 2008 and 2009, it was reported that the highest number of GM crops for molecular farming are under developed in laboratory or green house level in all the world. Likewise, in Korea, 171 events from 49 plant species are under developed to introduce several important traits. At present, about 10 events are under field test to select elite lines for RA application. For the first time, herbicide resistance turfgrass developed by Korean research team has been submitted for RA and currently under requested for additional data. Moreover, GM rice resistant to leaf roll (folder) disease is expected as a next event to be submitted for RA application.

• Journal of the Korean Wood Science and Technology
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• v.41 no.4
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• pp.358-373
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• 2013

In this study, both mild acid and alkali treatments with 1.0 wt% and 2.0 wt% of $H_2SO_4$ and NaOH solution were applied to evaluate the effects on chemical compositions of wood biomass. Yellow poplar (Liriodendron tulipifera L.) and larch (Larix kaempferi C.) were chosen due to major species planted in Korea. Chemical treatments of biomass were carried out by being soaked in either acid or alkali solution with 1:20 ratio for 72 hours at ambient temperature. Afterward, lignin, 5 major reduced sugars, ash contents and elemental composition were determined. To statistically understand the relationship between samples and chemical treatments, the Tukey test, simple linear regression model and ANOVA analysis were introduced using a statistical software R. As results from both wet chemistry and statistical analysis, yellow poplar was more affected on the lignin and xylose contents by acid treatments under these experimental conditions. Meanwhile, larch was more affected on the composition of galactose and lignin by alkali treatments. A series of results in this study would show that equivalent chemical treatment makes a change the chemical composition of each species.

• The Journal of Engineering Geology
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• v.28 no.2
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• pp.207-215
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• 2018

Almost all countries of the world have recently made great efforts to reduce green-house gases to alleviate the global warming threatening human survival, because a huge amount of carbon dioxide as one of the main green-house gases has been emitted from the combustion processes of fossil fuels such as coal and oil. $CO_2$ capture and storage (CCS) technology is a representative method to diminish the green-house gases, and actively investigated by many countries. This study focuses on the design and construction of a high pressure $CO_2$ injection facility to store it to underground, which is the first $CO_2$ injection in Korea following the steps of the $CO_2$ capture from large $CO_2$ emission sources and transportation to the sea. Injection tests of $CO_2$ on the platform on the sea were carried out in Yeongil Bay of Pohang city in the early 2017. Thus, we were able to perceive the necessary operating conditions of the injection facility, injection characteristic, and knowhow of the injection facility. The results obtained from the injection test shall be utilized for facility upgrades and scale-ups.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.865-875
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• 2018

Selection of optimum reaction conditions during deoxygenation process of palm oil is essential factor to obtain the maximum yield of bio-jet fuel. In this context, the deoxygenation of palm oil was carried out in a fixed bed reactor with an internal diameter of 1 inch loaded with a 1 wt.% $Pt/Al_2O_3$ catalyst. The composition of the organic liquid product(OLP), which can be utilized as a transportation fuel through the upgrading process, was analyzed by a gas chromatography method. The palm oil/hydrogen ratio and hydrogen pressure in the feed affected the decarboxylation(DCB) and hydrodeoxygenation(HDO) reactions, resulting in a change in the composition of the OLP. As the reaction temperature increased, the continuous cracking reaction of the deoxygenation product was promoted and the product composition in the $C_5{\sim}C_{14}$ region was increased. Thus, the results can help to understand the characteristics of deoxidation reaction of palm oil as well as the subsequent process, hydro-upgrading, to obtain the maximum yield of bio-jet fuel.