• Clean Technology
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• v.22 no.3
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• pp.196-202
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• 2016

In this study, ceria- based catalysts were prepared for dimethyl carbonate (DMC) synthesis and reaction conditions were evaluated for finding the optimal reaction route. In order to find optimal catalysts for DMC synthesis, calcination temperature and Cu(II) impregnation amount were evaluated. The oxidative carbonylation using methanol, carbon monoxide and oxygen and the direct synthesis using methanol and carbon dioxide were introduced for producing DMC. Following the law of Le Chatelier, the dehydration reaction was applied for enhancing the reactivity (methanol conversion) as removing water during the reaction. 2-cyanopyridine, as a chemical dehydration agent, was used. In the case of the oxidative carbonylation, methanol conversion rate increased from 15.1% to 38.7% and the DMC selectivity increased from 0% to 98.8%. In the case of the direct synthesis, methanol conversion rate increased from 1.0% to 77.8% and the DMC selectivity increased from 41.2% to 100.0%.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.2
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• pp.225-233
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• 2008

Accoring to the worldwide interest to control CO$_2$ which contributes to global warming 50%, new techniques to reduce CO$_2$ are under development. Therefore, this study investigated that CO$_2$ absorption/regeneration of Sodium-based dry sorbent and the effect of SO$_2$ concentration in the fixed bed reactor. The dry sorbents were prepared in the condition of different PVA contents and calcination temperatures. As the results of this study, BET surface area showed 832.79 m$^2$/g and SEM result showed possibility as dry sorbent due to having of much micropore distribution. Also, the fixed bed reactor showed decreased CO$_2$ absorption capacity with SO$_2$ injection, because of the generation of $Na_2SO_3$ and $Na_2SO_4$.

• Food Science and Preservation
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• v.19 no.1
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• pp.26-30
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• 2012

The effect of browning inhibitors on quality properties of fresh-cut strawberries was investigated. Half-cut strawberries were treated with dipping solutions alone and with combinations of 1% ascorbic acid, 1% citric acid, 1% sodium chloride, and 1% magnesium chloride, were packaged with low density polyethylene bags, and were kept for 24 hours at $4^{\circ}C$. The levels of oxygen and carbon dioxide in the packages of the samples treated with the combined solutions were the highest and the lowest, respectively. The loss of L value and flesh firmness of fresh-cut strawberries was retarded by the combined solutions than by the dipping solutions alone. The soluble solids and pH were not affected by the browning inhibitor. These results suggest that mixture of ascorbic acid, citric acid, sodium chloride, magnesium chloride may prevent browning and softening of fresh-cut strawberries.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.6
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• pp.788-793
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• 2012

This study was focused on the estimations of air pollutants, such as PM(Particulate matters), SOx(Sulfur Oxides), $CO_2$(Carbon diOxides) and NOx(Nitrogen Oxides), from a diesel propulsion engine installed on a naval vessel. Legislative and regulatory actions for exhaust emissions from ships are being strengthened in international communities and national governments to protect human health and the environment. In this context, various technologies have been developed from all of the nations of the world to meet strict standards. These regulations are based on commercial ship applications and according to size, but are not suitable for military naval vessels, which have much different engine operating conditions and hull architectures. Additionally, there is no international emission control system for military ships. Emission factors have been updated for commercial ship types from work at various research institutes; however, it is difficult to develop emission factors for military vessels because of their characteristics. In this paper, exhaust emissions from diesel engines installed on naval vessels under steady navigation condition were estimated with emission inventory methodology applied to ocean going vessels using fuel-based methods and fuel sulfur content analysis.

• Food Science and Preservation
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• v.8 no.3
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• pp.258-263
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• 2001

This experiment was conducted to measure the physiological qualities and the chemical compositions of garlic bulb (Allium sativum L) stored in air and controlled atmosphere at 0$\^{C}$ for 4months. There were no significant differences in physiological qualities such as soluble solid, dry weight and firmness by O$_2$ and CO$_2$ concentrations during 4 months of storage. The surface color of garlic cloves changed toward more dark direction in Hunter color surface with storage. CA storage inhibited the sprout growth by 50% and had no significant difference in root growth. Garlic stored in CA showed lower level of pungency, especially CA of low oxygen concentration (1%) showed the lowest level of pyruvate. Garlic stored in high CO$_2$ concentration(20%) showed the lowest level of fructan concentrations and the highest free sugar concentrations.

• Korean Journal of Plant Tissue Culture
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• v.26 no.4
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• pp.241-244
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• 1999

The effect of Milliwrap and Uniwrap attached to the lid on the growth and acclimation of lily growing in vitro was investigated. Milliwrap treatment increased the plant height 1.6 and 1.2 times higher than control in 'Dame Blanche' and '94-36', respectively, plant height of 'Dame Blanche' was 6.1㎝ and '94-36' line was 13.4 ㎝. Two treatments slightly inhibited the fresh weight in 'Dame Blanche', whereas Milliwrap and Uniwrap enhenced the fresh weight more than 30% in '94-36'. Leaf width (1.0 ㎝) of Milliwrap treatment was most wide, which was 2.5 times higher than that of control. In the fresh weight of bulblets, the fresh weight per bulblet of treatment was higher than control in '94-36', but the number of bulblets per scale were few in the treatment to control. In the air composition of culture vessel, ethylene content (0.03 ppm) was low in the Milliwrap treatment compared with the control. CO₂ content of control was higher than treatments as 0.11% and it was about 3 times to air condition of out side. The acclimation ratio of Milliwrap treatment was higher as 85.1% and control was similar with Uniwrap treatment.

• Polymer(Korea)
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• v.37 no.2
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• pp.249-253
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• 2013

From poly(lactic acid) (PLA) and poly(propylene carbonate) (PPC) synthesized using $CO_2$, a PLA/PPC/PLA layered film is prepared by coextrusion and then stretched to uniaxial orientation. The mechanical, optical, and barrier properties and shrinkage of the prepared film were investigated in detail. The maximum shrinkage of PLA/PPC/PLA film reached to 60% at $75^{\circ}C$. With increasing PPC content, the ratio of shrinkage of the film was increased and its shrinkagerate was increased. The ratio of shrinkage of the film decreased with increasing stretching temperature. The prepared film has oxygen and vapor transmission barrier properties. In this study, the PLA/PPC/PLA film is expected to be commercialized as a environmentally friendly shrinkable film.

• Journal of the Korean Institute of Gas
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• v.21 no.3
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• pp.39-45
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• 2017

The LNG storage tank as core facility of LNG industry is mainly composed of the inner tank of nikel 9% steel and the outer tank of prestressed concrete. To respond proactively increased risk of structure performance deterioration due to fatigue of the inner tank and durability reduction of the outer tank, life evaluation program for LNG storage tank is needed. In this study, life evaluation program for LNG storage tank was developed to assess fatigue of the inner tank and durability(carbonation and chloride attack) of the outer tank. By defining the main three scenarios in the inner tank, the fatigue life analysis is conducted from structural analysis and Miner's damage rule. Carbonation progress of the outer tank is predicted according to thickness of cover concrete by using carbon dioxide contents and data of penetration depth. To consider a variety of input conditions and a reliability in results of chloride attack, the evaluation of choride attack for the outer tank is constructed through Life-365 program of open source.

• Korean Journal of Food Science and Technology
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• v.18 no.3
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• pp.210-214
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• 1986

The culture conditions and cell composition of a hydrogen bacterica, Alcaligenes eutrophus ATCC 17697. were investigated. Optimum pH and temperature for cell growth under autotrophic condition ($H_2$ as energy source, $CO_2$, as crabon source) were around 7.0 and $30^{\circ}C$, respectively. Effect of oxygen partial pressure in the range of 0.059 atm and 0.27 atm on cell growth was also studied. Maximum specific growth rate $({\mu}max=0.31hr^{-1})$ was observed at 0.11 atm of oxygen partial pressure $(H_2:O_2:CO_2=7:1:1)$. The contents of crude protein, nucleic acid and ash in cells were 69.2%, 17.6%, and 3.62%, respectively.

• Journal of Applied Biological Chemistry
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• v.64 no.4
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• pp.351-356
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• 2021

Changing environmental conditions can affect plant growth by influencing water and nutrient transport and photosynthesis. Plant physiological responses under changing environmental conditions can be non-destructively monitored using electrodes as plant induced electrical signal (PIES). Objective of the study was to monitor PIES in response to increased CO₂ and decreased photosynthetic photon flux density (PPFD). The PIES increased during day time when transpiration and photosynthesis occurs and monitored CO₂ concentration was negatively correlated to the PIES. Enhanced CO₂ concentration slightly reduced PIES, but the effect of increased CO₂ was limited by light intensity. The effect of reduced PPFD was not appeared immediately because water and nutrient transport was not promptly affected by the light. The study was conducted to evaluate short-term effect of increasing CO₂ and decreasing PPFD, hence proline content and chlorophyll fluorescence was not significantly affected by the conditions.